967 resultados para Relativity (Physics)


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Distance education has developed in the past 25 years or so as a way of supplying education to people who would not have access to local college education facilities. This includes students who live in remote regions, students who lack mobility, and students with full-time jobs. More recently this has been renamed to "online learning". Deakin University in Australia has been teaching freshman engineering physics simultaneously to on-campus and online students since the late1990's. The course is part of an online Bachelor of Engineering major that is accredited by the Institution of Engineers Australia.* In this way Deakin answers the call to provide engineering education "anywhere, anytime."**The course has developed and improved with the available educational technology. Starting with printed study guides, a textbook, CD-ROMS, and snail-mail, and telephone/email correspondence with students, the course has seen the rise of websites, online course notes, discussion boards, streamed video lectures, web-conferencing classes and lab sessions, and online submission of student work. Most recently the on-campus version of the course has shifted from a traditional lecture/tutorial/lab format to a flipped-classroom format. The use of lectures has been reduced while the use of tutorials and practical exercises has increased. Primary learning is now accomplished by watching videos prepared by the lecturer and studying the textbook.Offering this course for several years by distance education made this process considerably easier. Most of the educational "infrastructure" was already in place, and the course's delivery to a non-classroom cohort was already established. Thus many elements of the new structure did not have to be produced from scratch. Improvements to the course website and all the course material has benefited all students, both online and on-campus.The new course structure was delivered for the first time in 2014, has run for two semesters, and will continue in 2015. Student learning and performance is being measured by assignment and exam marks for both on-campus and off-campus students. Students are also surveyed to gauge how well they received the new innovations, especially the video presentations on the lab experiments. It was found that student performance in the new structure was no worse than that in the older structure (average on-campus grades increased 10%), and students in general welcomed the changes. Similar transitions are being implemented in other courses in Deakin's engineering degree program.This presentation will show how physics is taught to online students, outline the changes made to support flipping the on-campus classroom, and how that process benefited the off-campus cohort.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As part of Deakin’s Course Enhancement Program, The Faculty of Science, Engineering and Built Environment, the School of Engineering and Deakin Learning Futures, combined their resources to produce a series of video presentations to enhance the efficiency of physics practicals in the first-year engineering course. Along the way it was decided the unit also needed a complete overhaul in terms of content layout and delivery. And this was all to be done in a short time frame of a few months before start of Trimester 1, 2014. The end result includes eight professionally developed videos embedded into HTML pages of instruction and information within the CloudDeakin environment, a completely new navigation structure, and templated content pages with links to various resources. The production journey was not without it’s challenges and constraints, but the unit has been delivered, and the student feedback is in.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The main objective for physics based modeling of the power converter components is to design the whole converter with respect to physical and operational constraints. Therefore, all the elements and components of the energy conversion system are modeled numerically and combined together to achieve the whole system behavioral model. Previously proposed high frequency (HF) models of power converters are based on circuit models that are only related to the parasitic inner parameters of the power devices and the connections between the components. This dissertation aims to obtain appropriate physics-based models for power conversion systems, which not only can represent the steady state behavior of the components, but also can predict their high frequency characteristics. The developed physics-based model would represent the physical device with a high level of accuracy in predicting its operating condition. The proposed physics-based model enables us to accurately develop components such as; effective EMI filters, switching algorithms and circuit topologies [7]. One of the applications of the developed modeling technique is design of new sets of topologies for high-frequency, high efficiency converters for variable speed drives. The main advantage of the modeling method, presented in this dissertation, is the practical design of an inverter for high power applications with the ability to overcome the blocking voltage limitations of available power semiconductor devices. Another advantage is selection of the best matching topology with inherent reduction of switching losses which can be utilized to improve the overall efficiency. The physics-based modeling approach, in this dissertation, makes it possible to design any power electronic conversion system to meet electromagnetic standards and design constraints. This includes physical characteristics such as; decreasing the size and weight of the package, optimized interactions with the neighboring components and higher power density. In addition, the electromagnetic behaviors and signatures can be evaluated including the study of conducted and radiated EMI interactions in addition to the design of attenuation measures and enclosures.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mechanical conditioning has been shown to promote tissue formation in a wide variety of tissue engineering efforts. However the underlying mechanisms by which external mechanical stimuli regulate cells and tissues are not known. This is particularly relevant in the area of heart valve tissue engineering (HVTE) owing to the intense hemodynamic environments that surround native valves. Some studies suggest that oscillatory shear stress (OSS) caused by steady flow and scaffold flexure play a critical role in engineered tissue formation derived from bone marrow derived stem cells (BMSCs). In addition, scaffold flexure may enhance nutrient (e.g. oxygen, glucose) transport. In this study, we computationally quantified the i) magnitude of fluid-induced shear stresses; ii) the extent of temporal fluid oscillations in the flow field using the oscillatory shear index (OSI) parameter, and iii) glucose and oxygen mass transport profiles. Noting that sample cyclic flexure induces a high degree of oscillatory shear stress (OSS), we incorporated moving boundary computational fluid dynamic simulations of samples housed within a bioreactor to consider the effects of: 1) no flow, no flexure (control group), 2) steady flow-alone, 3) cyclic flexure-alone and 4) combined steady flow and cyclic flexure environments. We also coupled a diffusion and convention mass transport equation to the simulated system. We found that the coexistence of both OSS and appreciable shear stress magnitudes, described by the newly introduced parameter OSI-:τ: explained the high levels of engineered collagen previously observed from combining cyclic flexure and steady flow states. On the other hand, each of these metrics on its own showed no association. This finding suggests that cyclic flexure and steady flow synergistically promote engineered heart valve tissue production via OSS, so long as the oscillations are accompanied by a critical magnitude of shear stress. In addition, our simulations showed that mass transport of glucose and oxygen is enhanced by sample movement at low sample porosities, but did not play a role in highly porous scaffolds. Preliminary in-house in vitro experiments showed that cell proliferation and phenotype is enhanced in OSI-:τ: environments.^

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The low-frequency electromagnetic compatibility (EMC) is an increasingly important aspect in the design of practical systems to ensure the functional safety and reliability of complex products. The opportunities for using numerical techniques to predict and analyze system’s EMC are therefore of considerable interest in many industries. As the first phase of study, a proper model, including all the details of the component, was required. Therefore, the advances in EMC modeling were studied with classifying analytical and numerical models. The selected model was finite element (FE) modeling, coupled with the distributed network method, to generate the model of the converter’s components and obtain the frequency behavioral model of the converter. The method has the ability to reveal the behavior of parasitic elements and higher resonances, which have critical impacts in studying EMI problems. For the EMC and signature studies of the machine drives, the equivalent source modeling was studied. Considering the details of the multi-machine environment, including actual models, some innovation in equivalent source modeling was performed to decrease the simulation time dramatically. Several models were designed in this study and the voltage current cube model and wire model have the best result. The GA-based PSO method is used as the optimization process. Superposition and suppression of the fields in coupling the components were also studied and verified. The simulation time of the equivalent model is 80-100 times lower than the detailed model. All tests were verified experimentally. As the application of EMC and signature study, the fault diagnosis and condition monitoring of an induction motor drive was developed using radiated fields. In addition to experimental tests, the 3DFE analysis was coupled with circuit-based software to implement the incipient fault cases. The identification was implemented using ANN for seventy various faulty cases. The simulation results were verified experimentally. Finally, the identification of the types of power components were implemented. The results show that it is possible to identify the type of components, as well as the faulty components, by comparing the amplitudes of their stray field harmonics. The identification using the stray fields is nondestructive and can be used for the setups that cannot go offline and be dismantled

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Expertise in physics has been traditionally studied in cognitive science, where physics expertise is understood through the difference between novice and expert problem solving skills. The cognitive perspective of physics experts only create a partial model of physics expertise and does not take into account the development of physics experts in the natural context of research. This dissertation takes a social and cultural perspective of learning through apprenticeship to model the development of physics expertise of physics graduate students in a research group. I use a qualitative methodological approach of an ethnographic case study to observe and video record the common practices of graduate students in their biophysics weekly research group meetings. I recorded notes on observations and conduct interviews with all participants of the biophysics research group for a period of eight months. I apply the theoretical framework of Communities of Practice to distinguish the cultural norms of the group that cultivate physics expert practices. Results indicate that physics expertise is specific to a topic or subfield and it is established through effectively publishing research in the larger biophysics research community. The participant biophysics research group follows a learning trajectory for its students to contribute to research and learn to communicate their research in the larger biophysics community. In this learning trajectory students develop expert member competencies to learn to communicate their research and to learn the standards and trends of research in the larger research community. Findings from this dissertation expand the model of physics expertise beyond the cognitive realm and add the social and cultural nature of physics expertise development. This research also addresses ways to increase physics graduate student success towards their PhD. and decrease the 48% attrition rate of physics graduate students. Cultivating effective research experiences that give graduate students agency and autonomy beyond their research groups gives students the motivation to finish graduate school and establish their physics expertise.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Walking is the most basic form of transportation. A good understanding of pedestrian’s dynamics is essential in meeting the mobility and accessibility needs of people by providing a safe and quick walking flow. Advances in the dynamics of pedestrians in crowds are of great theoretical and practical interest, as they lead to new insights regarding the planning of pedestrian facilities, crowd management, or evacuation analysis. As a physicist, I would like to put forward some additional theoretical and practical contributions that could be interesting to explore, regarding the perspective of physics on about human crowd dynamics (panic as a specific form of behavior excluded).