Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 105-108).

A research report submitted by Safura Khan in partial fulfilment of the requirements for the degree Master of Science in Science Education, Faculty of Science. University of the Witwatersrand, School of Physics, September 2008. / This study investigated understanding of measurements by students in scientific activities that are experimentally based. The study focused on grade 12 high school learners in an urban South African School. The majority of these students were second language English speakers. Data were obtained through a written questionnaire given to students, to explore learners’ ideas about data collection, data processing and data comparison, in particular the need to repeat measurements and the implication of the scatter associated with numerical and graphical data. An alphanumeric coding scheme adapted from Lubben et al. (2000), was used as an analysis tool. This included categorising responses into point or set paradigms. The findings of this limited study maybe summed up as follows: There is some consistency in reasoning across the experimental phases of data collection and data processing but it was noted that there is little use of set reasoning. It seems that students had specific difficulties in understanding the role and value of statistical tools in assessing confidence in measurement. By and large the learners in this study did not appreciate the need for error analysis. The overall study suggests that though the correct procedures are followed students have little or no understanding of the factors taken into account during data analysis. The findings show that very few students are true set reasoners; 75% of the students chose to take an average because that is the way it was always done. Students’ views may have been influenced by either exposure to ‘cook book’ laboratory sessions or by the context of the questionnaire which asks for three repeats. The study also shows that students had specific difficulty in understanding the role and value of statistical tools in assessing confidence in measurement (Mc Dermott & Redish, 1999). In conclusion though analysis shows a large percentage of students appear to be point reasoners, they may appear at first sight to be set reasoners. The term average was used by students yet a recurring value was chosen. There is therefore a need to perform experiments in a meaningful context and move away from ‘cook book’ laboratories to appropriate non-traditional laboratory activities, so as to enhance higher order thinking.

The aim of this work is to investigate some algebraic and combinatorial aspects of group factorizations. The main contribution of this dissertation is a set of new results regarding factorization of groups, with emphasis on the nonabelian case. We introduce a novel technique for factorization of groups, the so-called free mappings, a powerful tool for factorization of a wide class of abelian and non-abelian groups. By applying a certain group action on the blocks of a factorization, a number of combinatorial and computational problems were noted and studied. In particular, we analyze the case of the group Aut(Zn) acting on blocks of factorization of Zn. We present new theoretical facts that reveal the numerical structure of the stabilizer of a set in Zn, under the action of Aut(Zn). New algorithms for finding the stabilizer of a set and checking whether two sets belong to the same orbit are proposed. / by Vladimir Bozovic. / Thesis (Ph.D.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, FL : 2008 Mode of access: World Wide Web.

The purpose of this research is to develop a new approach to estimate the effective leakage area using the inverse modeling process as an alternative to the blower door test. An actual office building, which is the head quarter of Energy Efficiency Hub, was used as an example case in this study. The main principle of the inverse modeling process is comparing the real monitor boiler gas consumption with the result calculated from the EnergyPlus model with a dynamic infiltration rate input to find the best estimation of the parameter of effective leakage area (ELA). This thesis considers only the feasibility of replacing the blower door test with the calibration approach, so rather than attempting an automated calibration process based on inverse modeling we deal with generating a first estimate and consider the role of model uncertainties that would make the proposed method less feasible. There are five steps of the whole process. First, we need to customize our own actual weather data (AMY) needed by the energy model (EnergyPlus model), which can help increase our quality of the result. Second, create the building energy model in EnergyPlus. Third, create a multi-zone model using CONTAM with different ELA estimation of each facade to calculate the dynamic infiltration rate of each ELA estimate. Fourth, input the dynamic infiltration rate got from the CONTAM model to EnergyPlus model and output the boiler energy consumption. Fifth, compare the boiler gas consumption from the model and the real monitor data and find the best match between the two and the corresponding ELA, which gives the best estimate from the whole inverse modeling process. From the simulation result comparison, the best estimation of the total building ELA from the inverse modeling process is the 23437cm2 at 4pa, while the result from the blower door test is 10483cm2 at 4pa. Because of the insufficient information of the building and also the uncertainty of the input parameters, the study has not led to a definite statement whether the proposed calibration of the ELA with consumption data can replace a blower door test to get an equally valid or even better ELA estimate, but it looks feasible. As this this case study is done in a deterministic context, the full feasibility test should be conducted under uncertainty. A first step towards this will talk be discussed in chapter 4.

In mesoscale manufacturing desired dimensional and surface characteristics are defined, but edge conditions are not specified in design. The final edge conditions that exist in mesoscale objects are created not only by the manufacturing process but, because of their size, also by part handling procedures. In these parts, the concern is not only with burrs, which can be formed by some mesoscale manufacturing processes, but also with the shape and size of the edge. These properties are critically important as the edge can constitute a large percentage of the smallest features of mesoscale objects. Undefined edge geometry can result in measurement, assembly, and operational difficulties. Due to the potential problems caused by edge conditions, it is desirable to have the ability to measure and characterize the edge conditions of parts. This thesis considers mesoscale measurement tools to provide an edge measurement tool recommendation based on edge size and properties. A set of analysis techniques is developed to determine the size and shape of the measured edge, locate any local inconsistencies such as burrs or dents, and track trends in calculated parameters as a function of edge position. Additionally, a standard method for communicating design requirements is suggested in order to differentiate between acceptable and unacceptable edges.

Thesis (MScIng)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Wool has been an important product in Utah since the pioneers arrived. The Mormon pioneers had with them 358 head of sheep upon entering the Salt Lake Valley. At that time there were also 12 head of sheep near Ogden, Utah belonging to Miles Goodyear, a trading post operator. These early people were very dependent upon wool for their clothing and numerous other products.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2005. / In the inverse finite element method (iFEM), given a finite element model of a structure and imperfect displacement measurements, the external loads acting on the structure can be assessed. The basic idea behind iFEM is the optimization of a quadratic cost function of the difference between the measured and estimated values, with a high cost corresponding to a high precision of the measurements. In the present research it is firstly shown how the iFEM theory was broadened to accommodate for strain measurements through the construction of cost matrices to express the cost associated with the estimation of the response. The main focus of the research falls however on the influence that the measurement set-up has on the quality of the iFEM estimates. Only a limited number of measurements may be available, therefore it is essential to plan the measurement set-up carefully to obtain the highest quality of estimates. The number of measurements and the precision required to obtain a realistic result from an iFEM analysis is also a factor which plays a role and varies for different types of measurements. A numerical method for systematic sensitivity study of the measurements set-up without involving the actual measurement data, is presented. Two examples consisting of structures with both displacement measurements and strain measurements being taken, are presented. It illustrates how the sensitivity study method can be used to plan a more effective measurement set-up.

We report the design and fabrication of a micro-mechanical oscillator for use in extremely small force detection experiments such as transverse force measurements of a moving vortex and Nuclear Magnetic Resonance Force Microscopy (NMRFM). We study the basic physics of the double torsional mechanical oscillator, and pursue double torsional oscillators with small spring constants, high resonance frequencies, and high quality factors. Using a series of semiconductor manufacturing techniques, especially using the electron-beam lithography technique, we successfully micro-fabricate double torsional mechanical oscillators from silicon-on-insulator wafers. We conduct characterization experiments to extract important parameters of a mechanical oscillator, including the resonance frequencies, spring constants, and quality factors. We focus on the four typical resonance modes of these oscillators, and then compare the force detection sensitivity of each mode. Eventually we apply these force sensitive oscillators to gold micro-mass measurements, and achieve very small mass detection. In the future we are going to continue to micro-fabricate thinner oscillators to reduce the spring constants, and improve the quality factors by designing more suitable geometric shapes and by pursuing annealing studies. Thus, we might be able to achieve single nuclear spin measurements using NMRFM. / text