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Polymers of Intrinsic Microporosity (PIMs) are a new class of microporous material combining excellent solution processability with great structural diversity. The microporosity of PIMs derives from the inefficient packing of rigid and contorted polymeric chains. PIM membranes show great potential in gas separations (e.g., CO2/CH4, CO2/N2, O2/N2, H2/N2). However, they suffer from a well-defined tradeoff relationship between gas permeability and selectivity. Novel PIMs were designed and synthesised to investigate structure-property relationships and to provide a guideline for designing a new membrane material, which can provide a good balance of gas permeability and selectivity. In the first part of this thesis, two fluorinated benzotriptycene polybenzodioxin polymers were prepared. These benzotriptycene-based PIMs exhibit ultra-high permeability with remarkable selectivity for carbon capture (CO2/N2) and natural gas purification (CO2/CH4), and defined the new upper bounds for these gas pairs together with four other benzotriptycene PIMs. In particular, the fluorinated polymers showed a better performance for CO2/CH4 and He/CH4 than alkyl substituted benzotriptycene based PIMs due to their higher solubility selectivity resulting from the low CH4 sorption in the fluorinated polymers. In the second part, a fluorinated and non-fluorinated benzomethanoanthracene PIMs (PIM OCF and PIM-OCP) were designed and synthesized in which fluorine atoms illustrated a minor effect on polymer microstructure confirmed by molecular simulation. The improved CO2/CH4 solubility selectivity exclusively derives from the inclusion of the fluorocarbon unit. The perfluoroalkyl chain substituent was also observed to reduce the CH4 sorption and improve the solubility selectivities of CO2/CH4, He/CH4 and H2/CH4, although the reduced size selectivity of perfluoroalkyl chain substituted polybenzodioxin polymer and low surface area of the perfluoroalkyl chain substituted Tröger’s base polymer limit their potential applications. In the last chapter, dibenzeno-6,13-methanopentacene (DBMP), a bridged bicyclic structure with a bulkier structure than that of triptycene, was utilized for PIM synthesis. The membrane of the homopolymer (PIM-DBMP) proved too fragile for membrane fabrication. Therefore, the potential of DBMP for gas separations was investigated using a series of copolymers composed of DBMP and 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane (TTSBI). The gas permeability of the copolymers demonstrated that the introduction of DBMP improves the gas permeability and selectivity simultaneously, overcoming the challenging tradeoff relationship. PIM-DBMP was further modified via amidoxime functionalisation, which was anticipated to improve the membrane’s mechanical properties. As expected, a robust membrane of amidoxime-PIM-DBMP was achieved which showed promising gas separation performance.

For much of the twentieth century, teacher use of codeswitching (CS) was seen as a contentious issue within ELT, because of the assumption that English is best taught and learned without the use of students' first language (L1). In recent decades, however, studies focusing on the context of EFL classrooms where teachers and students share the same L1(s) call for a re-examination of the role of the L1 in classroom instruction. However, in China, 'English-only', the exclusive use of English as the medium of instruction, has been viewed as an 'unwritten rule' by many ELT institutions, which is inconsistent with the CS practices of many teachers in their teaching. This thesis explores teachers' CS practices and their perceptions of CS use in university EFL classrooms in China. The study employed (1) semi-structured interviews to investigate teachers' views towards L1 use, (2) audio-recorded classroom observations to examine the practice of CS by the teachers in the classroom, and (3) follow-up stimulated-recall interviews to elicit teachers' rationales for their CS practices. The findings indicate that teachers' perceptions of CS use, and their classroom practices in specific circumstances, are more complex than has previously been acknowledged. The findings show that the majority of teachers, while recognizing the importance of English use in the EFL classroom, identify a range of valuable functions for L1 use in their teaching. From a pragmatic perspective (Verschueren, 1999), the study identifies a number of individual, environmental and classroom-specific factors that may affect teacher CS use in the EFL classroom. The study offers empirical evidence for EFL teachers regarding L1 use in their teaching, affirms the value of L1 use, and sheds light on how and why the L1 may be used in EFL classrooms.

The thesis is arranged as three topics. The first topic is a joint work with my supervisor Paula Hill. We compare diverse measures of default risk (including both academic models and credit ratings) before examining its relationship with stock returns. The second topic is a joint work with my supervisors Neslihan Ozkan and Paula Hill and we examine the relationship between firm default risk and executive compensation. The third topic is a sole authored work in which I provide more evidence that correlated overpayments of CEOs and directors are symptomatic of agency problems related to cronyism. Cronyism is a term used to describe a phenomenon in which directors do not protect the interests of shareholders and choose to collude with the CEO for private benefits (Brick et al., 2006). In the first essay, we find considerable variation in the mean probability of default across our academic models. The correlations between the measures of default risk are significant at a 1 % level and yet tend to be less than 50%. The rating-based measures of default risk (i.e. S&P's and Moody's ratings) are highly correlated with each other (0.962) but have a maximum correlation of 0.498 with the academic models. Moreover, we show that different assumptions can lead to divergent assessments of default risk even where default risk measures appear similar theoretically, such as those based on the theories of Black and Scholes (1973) and Merton (1974). Nonetheless, we find that the relationship between stock returns and diverse measures of default risk tends to be consistent. Default risk is a significant determinant of stock returns with a "hump backed" relationship, as predicted by Garlappi and Yan (20 11). This relationship holds even after controlling for very high default risk firms, which contrasts with the findings of Avramov et al. (2009) that the relationship between stock returns and default risk is driven by firms with low credit quality. Given the reasonable consistency in the observed relationship between stock returns and diverse measures of default risk, we find little evidence that differences in the conclusions of The thesis is arranged as three topics. The first topic is a joint work with my supervisor Paula Hill. We compare diverse measures of default risk (including both academic models and credit ratings) before examining its relationship with stock returns. The second topic is a joint work with my supervisors Neslihan Ozkan and Paula Hill and we examine the relationship between firm default risk and executive compensation. The third topic is a sole authored work in which I provide more evidence that correlated overpayments of CEOs and directors are symptomatic of agency problems related to cronyism. Cronyism is a term used to describe a phenomenon in which directors do not protect the interests of shareholders and choose to collude with the CEO for private benefits (Brick et aI., 2006). In the first essay, we find considerable variation in the mean probability of default across our academic models. The correlations between the measures of default risk are significant at a 1 % level and yet tend to be less than 50%. The rating-based measures of default risk (i.e. S&P's and Moody's ratings) are highly correlated with each other (0.962) but have a maximum correlation of 0.498 with the academic models. Moreover, we show that different assumptions can lead to divergent assessments of default risk even where default risk measures appear similar theoretically, such as those based on the theories of Black and Scholes (1973) and Merton (1974). Nonetheless, we find that the relationship between stock returns and diverse measures of default risk tends to be consistent. Default risk is a significant determinant of stock returns with a "hump backed" relationship, as predicted by Garlappi and Yan (20 11). This relationship holds even after controlling for very high default risk firms, which contrasts with the findings of A vramov et al. (2009) that the relationshi p between stock returns and default risk is driven by firms with low credit quality. Given the reasonable consistency in the observed relationship between stock returns and diverse measures of default risk, we find little evidence that differences in the conclusions of performance. However, these effects of excess compensation on CEO turnover are mitigated by total institutional ownership. In addition, as institutional ownership increases, the positive effect of director compensation on CEO cash compensation is also significantly reduced. FUlther, in firms with high levels of institutional ownership the negative impact of excess compensation on firm performance is weakened. The fact that external monitoring by institutional investors mitigates the effects of excess compensation means the excess compensation of directors and CEOs is at least partly due to agency problems.

Living in an era of test-based accountability systems, how do we hold accountability tests accountable? Many accountability decisions made today are based on the assumption that test scores successfully reflect the effect of instruction. However, only instructionally sensitive assessments, not the instructionally insensitive ones, reflect the impact of instruction. The purpose of this study is to explore the relationship between students' instructional experiences and their test scores on standardized achievement test items. The Mantel-Haenszel statistics, logistic regression and judgmental item-detection approaches were used to identify instructionally sensitive items in the Kansas Mathematics Interim Assessment for seventh graders. The two empirical methods performed very similarly. Many instructionally sensitive items were identified by the empirical methods. No strong agreement between the empirical and judgmental approaches was found. The implications of this study to educators and policymakers, the limitations of this study, and the directions for further studies are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

Studying contemporary Chinese art is not purely an aesthetic choice, but rather a response to the context of the times. From the initial development in the 1870s to the capital intervention in the 1990s, Chinese contemporary art began to internationalize and globalize. The artists who matured during this period now form the backbone of Chinese contemporary art. Having experienced the turmoil of Chinese society, they explore politics and ideology through their artwork with great depth and nuance. Song Dong, himself an artist of this generation, has been exploring ideas related to everyday reality, memory, and social issues through his artwork. This thesis examines three of Song Dong's works, namely Touching my father (1997-2011), Father and Son in the Ancestral Temple (1998), and Waste Not (2005), all of which revolve around the theme of family. In addition to considering the artist himself and his familial relationships, this study contextualizes Song Dong's works within the social and political landscape of contemporary China. Through this analysis, the thesis aims to explore the theme of family in greater depth. It also involves an exploration of censorship in Chinese contemporary art and how artists such as Song Dong use subtle artistic language to express their personal opinions.

This thesis consists of three chapters. It studies, as a broad theme, the effectiveness of several institutional changes on individual decision-making based on experimental evidence. Chapter 1 is self-contained, with results purely based on a laboratory experiment. Chapter 2 and Chapter 3 are based on one field experiment in education. Chapter 2 describes the experimental settings and presents the overall results of the experiment, whereas Chapter 3 extends the analysis and focuses on treatment effects on women and men respectively. Chapter 1 shows how reward or punishment opportunities change contributions in a public goods game with 'privileged' members, where 'privilege' indicates that one's per-unit contribution to the public good produces a higher monetary return than is the case for others in the group. The main finding is that reward opportunities strongly increase group contributions in such groups while punishment opportunities do not. Reward also mitigates contribution decay over successive periods and improves social welfare. Chapter 2 mainly studies how rank incentives (i.e., relative performance information) in a milestone-based online assignment system affect students' academic performance. I find that rank incentives increase the likelihood of a student putting more effort in the online assignment. Rank incentives also have positive effects on low-performing students' exam marks while they have negative effects on high-performing students' exam marks. The positive effects seem driven by increased self-perceived stress, increased effort, and decreased procrastination. The negative effects seem driven by increased self-perceived happiness and re-allocation of effort. Chapter 3 studies how rank incentives and milestone information (i.e., information with reference to achievement milestones corresponding to different amounts of points earned) affect men's and women's academic performance differently. Women with access to the rank incentives experience a 0.19 SDs mark decrease in the first midterm, compared to women without this access. In the absence of relative performance information, men with access to the milestone information experience a 0.26 SDs mark increase in the final exam, compared to men without the access. The negative effects on women seem driven by their increased stress level, whereas men's improved exam performance seem driven by increased effort.

One of the most uncertain aspects of the climate system are aerosol particles and their interaction with clouds. Aerosol aging in the aqueous phase often involves reactive oxygen species such as hydroxyl radicals (OH), hydrogen peroxide (H2O2), superoxide (O2•-), and organic peroxides. In clouds, chemistry driven by hydroxyl radicals is a well-known contributor to production of secondary organic aerosols. OH in cloud and fog droplets originate from various sources, and models currently assume the main source of hydroxyl radicals in clouds is uptake from the gas phase. Work done previously in the group suggested a new, potentially substantial source of OH in cloud droplets when exposed to near UV light. In this study, we are able to produce similar behavior to field sample observations from mixtures of Fe(II) and peracetic acid (PAA) in the presence of light. We investigate this reaction to see if we can explain the ‘OH burst’ which occurs within moments of sample preparation. This is a previously unrecognized reaction and we observe a concentration-saturation effect to the amount of OH produced in the burst. We observe the OH burst from the reaction of Fe(II) and PAA in 320 nm light and in dark conditions. The reaction in the presence of near UV light immediately produces almost double the OH as the reaction in the dark demonstrating a clear light dependence. This is a possible photo-Fenton like reaction cycling Fe(II) amplifying the OH production. At higher concentrations of Fe(II) and PAA molar yield of OH decreases in both the light and dark conditions, producing less OH per �M of reactant compared to lower concentrations of either Fe(II) or PAA. Inhibition from iron-organic complexes or saturation effects are possibly limiting OH yield at high concentrations of initial reactants.

Following the adoption of a socialist market economy throughout the late 1970s and 1980s, the Chinese city has accommodated radical changes in its urban landscapes, especially the dramatic transformation of large industrial sites. Along with the rapid urban transformation and the neglect of historic cores, Chinese cities are witnessing the rapid disappearance of industrial heritage. This negative reality of conservation practice raises a fundamental question about the reasons for such cultural myopia. To reveal the main factors that dominate the results of brownfield regeneration projects in urban China, this thesis reviewed theories on the production of space and the literature on the Chinese context. A single case study approach was adopted, collecting data from semi-structured interviews, document reviews and popular media. Through an investigation in the major industrial inland city of Chongqing, the thesis examined how the idea of industrial heritage reuse has travelled as a global concept with its Chinese precedents to Chongqing, and why the idea has been diluted in the regional context. The case study of the Chongqing Steel Factory regeneration project revealed that the negative outcome of industrial heritage conservation was associated with Chongqing’s contextual constraints, covering aspects of capital accumulation, entrepreneurial urban governance and the post-reform sociocultural environment. It was argued that the heritage value was dramatically sacrificed to short-term profitability in property development, when relatively weak economic conditions, entrepreneurial governance with a focus on investment return, a lack of strong heritage legislation and regulation, and limited local cultural support work together. These findings build on existing theories concerning the production of space and the urban policy mobility, and relate the concepts of idea learning and mutation, capital accumulation, power relations and social efforts for spatial justice to industrial heritage studies in the Chinese context. This thesis contributes knowledge to three distinct areas: firstly, to research on brownfield transformation; secondly, to industrial heritage studies; and thirdly, to Chinese urban studies. The Chongqing experience seeks to inspire researchers, practitioners and policy makers in the positive transformation of other industrial cities in China, which still retain numerous industrial sites with great potential to be reclaimed. This thesis thus supports better industrial heritage outcomes.

The main aim of this dissertation is to study the prediction of financial returns or squared financial returns. As is known, financial returns data have the distribution with fatter tails than the normal and often show significant correlation and the phenomenon of volatility clustering. To capture these features is the most challenging thing in modeling financial returns data. The most popular nonlinear time series models for financial returns data now are ARCH (Autoregressive Conditional Heteroscedasticity) and GARCH (Generalized Autoregressive Conditional Heteroscedasticity) models. Early this century, a Model-free prediction approach was also derived to understand this complex type of data. One application of the model-free approach, NoVaS (Normalizing and Variance-Stabilizing) transformation has been proved to outperform ARCH and GARCH models under stationary financial data. In Chapter 1, we extend the realm of application of NoVaS to non-stationary data and compare the performance with GARCH in the one-step point prediction and prediction intervals of squared financial returns. In addition, we show the applicability of NoVaS transformation for estimating realized volatility. A new approach to the multi-step ahead prediction of squared financial returns is defined and analyzed in Chapter 2. Our work on linear time series model such as Autoregression are shown in the last two chapters. Chapter 3 describes in detail the situations that a simplified autoregressive models should be considered and the theoretical support was also given there for further study. In the last Chapter, we construct the prediction intervals of regression with model selections in the bootstrap world, which give better performance than the standard bootstrap methods. All the work here are mainly focusing on financial returns time series.

A rapidly intensifying wintertime cyclone impacted the Hawaiian Islands from 11 to 15 December 2008. A detailed case study of the evolution of this meteorology “bomb” is conducted using the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR) data. The focus is on the dynamic forcing and large-scale settings between the deepening and decaying stages. Model sensitivity simulations are conducted using the Advanced Weather Research and Forecasting (WRF-ARW) model to diagnose the roles played by latent heat release on the evolution of the storm. Feedbacks of latent heat release contribute to the rapid cyclogenesis. Latent heat release enhances vertical motion in the eastern flank of the surface cyclone, which 1) increases the potential vorticity (PV) advection aloft; 2) causes surface pressure falls underneath with stronger cyclonic flow; 3) strengthens the low-level frontogenesis as cold and warm air are brought into juxtaposition and 4) brings moisture from the tropics into the warm sector with increased southerly winds. With a westward tilted vertical structure, the feedback of latent heat release further increases the upper-level forcing as the enhanced low-level horizontal temperature advection deepens the upper-level trough and intensifies the upper-level ridge. During the decaying stage, latent heat release slows down the cyclolysis with similar processes, but the impact and feedbacks of latent heat release are less significant as compared to the deepening stage due to 1) decreasing moisture and low-level instability as the cyclone moves northwestward, and 2) less significant westward tilted structure. The enhanced rising motion associated with PV advection aloft is in the northeast quadrant of the upper-level low, thus the feedback of latent heat release weakens the upper-level low. Furthermore, without a westward tilt of the trough axis, the enhanced horizontal temperature advection neither deepens the upper-level trough and intensifies upper-level ridge nor increases the upper-level forcing.

In this work, a thermoelectric energy harvester system aimed at harvesting energy for locally powering sensor nodes in nuclear power plant coolant loops has been designed, fabricated and tested. Different mathematical modeling methods have been validated by comparing with experimental results. The model developed by this work has the best accuracy in low temperature range and can be adapted and used with any heat sink, heat pipe, or thermoelectric system, and have proven to provide results closely matching experimental data. Using the models, an optimization of the thermoelectric energy harvesting system has been performed which is applicable to any energy harvester of this variety. With experimental validation, the system is capable of generating sufficient energy to power all the sensors and electronical circuits designed for this application. The effect of gamma radiation on this thermoelectric harvester has also been proved to be small enough through radiation experiment.

The marine Erebus Basin surrounds the volcanic Ross Island in McMurdo Sound, Antarctica. This basin has evolved under the influence of flexure driven by loading by the three volcanoes that make up Ross Island. Seismic reflection data west of Ross Island are used to document the seismic stratigraphic framework of the flexural basin. Five seismic units are mapped within the sedimentary infill of the basin. Seismic facies are documented within each unit, ranging from chaotic facies interpreted as volcanic mass flows and ice-proximal glacial deposits, to laminated units interpreted as alternating pelagic, hemipelagic and glaciomarine deposits. The volcanogenic units form part of the aprons around the volcano slopes and the glaciomarine units fill the axial basin.Two seismic sequences are defined based on patterns of surface depth and unit thickness. Seismic Sequence 1 is bounded by the Rj and Rk seismic surfaces, showing thickening and deepening toward Mount Bird volcano. Seismic Sequence 2 includes units from the Rk seismic surface up to the seafloor, and thickens and deepens toward Mount Erebus volcano. Seismic mapping thus shows evidence of two discrete sub-basins formed by Mt. Bird loading since 3.8-4.6 Ma and Mt. Erebus loading since ~1.31 Ma. Both units also show thickening in a zone northwest of Ross Island where accommodation space was formed by Terror Rift faulting, indicating that Terror Rift was still active when the Ross Island volcano loading occurred.The Bird-Erebus flexural basin has an overall wedge-shaped fill that thickens toward the volcanoes of Ross Island, typical of the geometry of other basins formed by volcano loads in ocean basins. The Erebus Basin is underfilled, with only ~325 m of infill, compared with >2000 m of fill typically found in moats around ocean island volcanic chains. Like stratal sequences of other flexural basins, the Bird-Erebus flexural basin fill shows onlap geometries in cross-moat profiles. However, unlike stratal sequences of other flexural basins, no offlap pattern is observed in either cross-moat or along moat profiles. Gravity flows related to mass wasting of Ross Island volcanoes are a significant component of the Bird-Erebus basin fill but, unlike other basins formed by volcano loads, is not the dominant fill. Instead, seismic facies mapping and AND-1B core show that a significant component of glaciomarine deposits occurs in the flexural basin. Glacial erosion removed some of the flexural basin fill, particularly along the regional Rk seismic surface.A 3D thin elastic plate model was used to simulate flexural basin evolution induced by Ross Island volcano loading, and to evaluate regional lithospheric strength. Using the dip angle of seismically mapped reflector surfaces as the constraint, the best fit lithospheric strength is represented by effective elastic thickness of 4-5 km. This weak lithosphere in the Ross Island region can be explained by faulting, thin crust, and high heat flow in this rift tectonic setting.

Fault location is very important for distribution systems, and quickly identifying the fault and restoring the system can help reduce the outage time and make the system more reliable. In this thesis, a method for locating faults on distribution systems is introduced to quickly identify the faulted feeder sections by using the overcurrent information from the switches in the system. Fuzzy logic is utilized. The proposed method can quickly and accurately locate faulted sections with different fault locations, fault types and fault resistances. The method is applicable to cases with single-faults or multi-faults, and is applicable to networks with multi-sources. The case study has demonstrated the effectiveness of the proposed method.

With the advancement of signal processing and other enabling technologies, new products and services have appeared in large numbers over the past decade, and are changing people's daily lives quickly and profoundly. They could not have occurred without the rapid development in areas like digital communications, information theory, detection and estimation, where resource allocation plays a crucial role.In this work, we study resource allocation for two classes of problems. The first class is rate allocation in digital systems. The functionality of modern digital systems can be broadly divided into two parts: communications and source coding. For communications, we systematically study the allocation problem from a game theory perspective for the multiuser downlink broadcast channel, and apply the solutions to the special case where spatial block diagonalization is combined with time-sharing to multiplex a subset of the users. For source coding, we consider the achievable sum-rate/distortion tradeoff for the Gaussian central estimation officer problem with a scalar source having arbitrary memory. We formulate the variational problem of minimizing the sum rate subject to a distortion constraint, and the conventional Lagrange method is extended to solve the problem. A sufficient condition is also found that can be used to verify if the necessary solution results in the minimal sum rate.The second class of problems is target localization. We analyze the performance of a reduced-dimension separable space-time adaptive processing algorithm for radar systems under the large array assumption. The study shows that in the asymptotic sense the simplified scheme performs as well as the fully adaptive algorithm with a significant saving in computational complexity. For target localization in wireless systems, we propose a two-stage approach in order to handle non-line-of-sight transmission based on mild assumptions regarding the propagation environments. For the first stage of positioning, we analyze the cases of scattering and reflection respectively, and propose methods to estimate the position and velocity of the moving target. Once the estimation is done, the results can be used as the initial values of extended Kalman filters in the second stage to track the subsequent movements of the target.

Nanostructured enzymatic biofuel cells with high power density output and prolonged lifetime were developed by the incorporation of carbon nanotubes into redox polymer-enzyme films. The performance of the enzymatic biofuel cells was optimized by dispersing carbon nanotubes with different surfactants, modifying the method of nanotube incorporation, and varying the nanotube type and loading. The first part of this work focused on fabricating high surface area of single walled carbon nanotubes (SWNTs) for construction of redox polymer-enzyme based electrodes. It was demonstrated that the deposition of SWNTs(6,5) films onto glassy carbon electrodes from suspensions of the non-ionic surfactant Triton X-100 resulted in the highest response to glucose, producing current densities of ~1.7–2.1 mA/cm2. In contrast the formation of SWNTs networks from anionic surfactant suspensions (i.e. sodium cholate and NaDDBS) showed a decrease in the glucose response. To demonstrate that these SWNTs networks could be applied to anodic films that contained enzymes other than glucose oxidase, we constructed redox polymer-enzyme films both with and without SWNTs but with the enzyme fructose dehydrogenase (FDH). We demonstrated that the electrochemical and enzymatic properties of FDH/redox polymer electrodes were highly dependent on both the pH of the enzyme solution and the redox polymer solution. The maximum current density of Fc-C6-LPEI/FDH electrodes was 245 µA/cm2. Modification of GCEs with SWNTs (6, 5) films prior to coating of the Fc-C6-LPEI/FDH films resulted in an increase in the fructose response to ~ 1 mA/cm2. Fabrication of enzymatic biofuel cells based on these films produced a power density of 29 µW/cm2 in response to fructose. The role of SWNTs conductivity was investigated by comparing the performance of electrodes coated with SWNTs networks made from dispersions of conductive SWNTs(7,6) and semiconducting SWNTs(6,5). It was demonstrated that network of SWNTs(7,6) showed higher glucose response than networks of SWNTs(6,5) when coated with a mixture of the ferrocene redox polymer (FcMe2-C3-LPEI) and the enzyme (GOx). Optimizing the composition of SWNTs(7, 6) networks resulted in a maximum current density response to glucose of 11.2 mA/cm2. Furthermore, a novel method (mixing/ two layer method) was developed by incorporating carbon nanotubes into redox polymer-enzyme hydrogel films that were deposited onto the SWNTs networks. This mixing/two layer method resulted in a further increase in the response to glucose to 16.2 mA/cm2 at 37 oC. In addition, the stability of FcMe2-C3-LPEI / GOx electrodes increased with the incorporation of SWNTs. Applying the optimized SWNTs method to cathodes that were coated with a chloro-ferrocene redox polymer (Cl-Fc-LPEI) and the enzyme laccase generated biofuel cells that produced a maximum power density of 802 µW/cm2 at 355 mV and at 37 oC. Finally, we evaluated the potential of high surface area vertically aligned multiwalled carbon nanotubes (MWCNTs) forests as an electrode platform. Coating of these MWCNTs platforms with a mixture of ferrocene redox polymer (FcMe2-C3-LPEI) and the enzyme glucose oxidase produced electrodes that were responsive to glucose despite the fact that a majority of the MWCNTs (>99%) were electrochemically inaccessible.

Abstract: Coke drums are vertical pressure vessels used in the delayed coking process in petroleum refineries. They are normally constructed of carbon or low carbon alloy steels internally clad with stainless steel to protect the coke drums from corrosion during operations. Significant temperature variation during the delayed coking process causes damage in coke drums in the form of bulging and cracking. Hundred thousands of dollars are spent to repair the units and the loss from the disruption of the production could be even much higher. There are studies on the fatigue life estimation for coke drums, but these are based on uniaxial strain-fatigue life curves at various constant temperatures, which do not consider cyclic temperature conditions. There are relatively few investigations involving experiments to simulate and predict the damage and fatigue life of coke drums. To more accurately analyze the fatigue damage mechanism of coke drums, a systemic-experimental investigation on fatigue behaviours of coke drum materials has been carried out in this study. A thermal-mechanical fatigue (TMF) testing system has been successfully designed and developed to perform the complex TMF tests. The developed system can successfully simulate cyclic thermal-mechanical loading conditions experienced by coke drums. In addition, an alternative strain control and measurement technique is developed for strain-controlled fatigue tests at elevated temperature. The fatigue lives of the candidate materials are first investigated under isothermal condition. More complex TMF tests are then performed on these candidate materials. Two coke drum base materials (C-½Mo and 2¼Cr-1Mo) are investigated and compared under isothermal and thermal-mechanical cyclic loadings. Based on the current experimental study and, in combination with the API survey data, it is concluded that C-½Mo is a better base material than 2¼Cr-Mo from the standpoints of fatigue resistance. Since the coke drums are constructed by welding a number of shell plates, the fatigue behaviours of weld and heat affected zone (HAZ) material are also studied. A modified four-point correlation (FPC) method has been developed to predict the fatigue lives of weld and HAZ material based on their tensile properties. Finally, based on the TMF data of the coke drum materials obtained through this study, along with a new statistical fatigue life prediction method developed in our group, the fatigue lives of coke drums can be more reasonably predicted. This study leads to better understanding of damage mechanisms occurring in coke drums. The comprehensive coke drum material data obtained through this study are valuable for designers and operators of coke drums. More important, a number of useful guidelines including optimal selection of materials, more accurate analysis method and reliable life prediction method for coke drums are summarized. Application of these guidelines will be beneficial for designing and manufacturing of more robust new coke drums, as well as for extending service lives of the existing coke drums from the operational and maintenance point of view.

International trade has been cited as a source of widening wage inequality in industrial nations. In this paper, I investigate how the structure of the wage premium has been impacted within the United States due to rising trade with China. Using the U.S. Census data, since China joined WTO, I find the presence of the skill premium and over time the skill premium is higher. A counterfactual exercise indicates rising U.S. exports to China increase the wages of workers, especially for high-skilled laborers, and the effect is more pronounced in 2010. At the same time, increasing imports from China increase wages of high-skilled workers in the U.S., but push wages down for low-skilled workers. I also find strong evidence that less trade costs dramatically increase individual's wage rates; and the more education he/she has, the more wage growth he/she can benefit from decreasing trade costs. Rising trade balances actually promote wages for unskilled workers and decrease wages for skilled workers and its impacts on wages are falling and become relatively modest in the year 2010. In the end, I conclude that overall speaking, rising trade with China and less trade costs widen wage inequality in U.S.

Second language learning has received much widespread attention from researchers, educators and parents. As with first language acquisition, word learning in a second language is a building block for further language development. Whereas many studies on bilingualism indicate that an infant’s capacity for vocabulary acquisition seems to extend to two languages from birth (Byers-Heinlein, 2010; Genesee & Nicoladis, 2007; Ng & Wigglesworth, 2007; Reynolds, 1991) and much applied research has been dedicated to teaching second language vocabulary to children and adults, very few studies have directly compared the differences between children’s and adult’s second language word learning. The effect of age on second language learning is highly controversial. This dissertation aims to address the question of whether early or late is better for learning words in a second language by examining the interaction between age and exposure approach. The current studies are designed to explore different exposure approaches for teaching words in a second language to monolingual learners of different ages. I approach this question by focusing on second language word learning through three studies, each examining one exposure approach for English-speaking monolinguals learning words in a second language (i.e., Mandarin) by: 1) providing translation equivalents; 2) mere exposure to natural second language input with a single event context; 3) mere exposure to natural second language input with multiple event contexts. These three approaches were examined with three different groups of monolingual English-speaking learners: 28-30 months olds, 5-6 year olds and young adults. This dissertation was also interested in whether the effectiveness of these approaches may depend on the native language experience or other cognitive capacities of the learners. Results found that adults responded more accurately and quickly than children, with no difference across exposure approaches. Both groups of children, in contrast, performed differently with different exposure approaches. They were able to successfully fast-map words to the referents only in the Mandarin-only approach with a single event context. Furthermore, adults’ foreign language aptitude and working memory were significant correlated with their performance in these laboratory studies of second language word learning.

Recent studies revealed differential usage of Alternative Polyadenylation (APA) in Arabidopsis thaliana wild-type and the oxt6 mutant in which the Oxidative Stress Tolerance 6 gene (OXT6) encoding cleavage and polyadenylation specificity factor 30 (CPSF30) is interrupted. In this thesis I confirmed the differential patterns of APA for the gene LHCB4.1, encoding light harvesting complex II subunit, in wild-type versus the oxt6 mutant under either normal conditions or light/temperature stresses by using reverse transcription followed by real time PCR. It suggests the regulatory roles of AtCPSF30 and environmental stresses in the expression level and APA selection of other genes. In addition, leaves of oxt6 plants subjected to dark treatment etiolated faster than that of wild-type under dark treatment. Under dark treatment, LHCB4 protein abundance and its associated complexes were significantly lower in the oxt6 plants than in wild-type as determined by using blue native polyacrylamide gel electrophoresis and western blots. These results suggest that oxt6 mutant affects photosystem productivity and may explain why oxt6 plants have reduced stature.

Biofuels have been widely recognized as a potential renewable energy source, and the United States’ government has been interested in producing ethanol from lignocellulosic biomass such as switchgrass. To evaluate whether lignocellulosic biomass based biofuels production is economically feasible, this paper estimated the capital investment outlays, operation costs, and net present value for investment in alternative switchgrass feedstock supply chain configurations in East Tennessee a 25 million gallon per year ethanol biorefinery. Two scenarios are analyzed in the study. The conventional hay harvest scenario includes the production, harvest, storage and transportation of biomass feedstocks from the fields to the biorefinery. The preprocessing scenario added preprocessing facilities into the biomass supply chain. According to various harvest, storage, preprocessing, and harvest equipment options, analysis and comparisons were made among different systems. The capital budgeting model developed in this study generated the optimal feedstock supply chain configurations to determine the largest net present value of cash flow from investment. Results of this study shown that with the Biomass Crop Assistance Program (BCAP) incentives, a round bale system using feedstock stored without tarp on pallets using custom hired equipment had the largest positive net present value. By comparison, if all the harvest equipment is purchased rather than custom hired, the stretch wrap baler preprocessing systems, using switchgrass harvested by a chopper with rotary cutter-header, was found to have a cost advantage over conventional hay harvest logistic systems (large round bale and large square bale systems) and pellet preprocessing systems. Assuming most likely values for switchgrass price and production costs, none of the feed stock supply chain configurations evaluated in this study produced a positive net present value when BCAP subsidies were assumed to not be available. However, without the BCAP incentives and based on combination of optimistic assumption, the round bale system using feedstock stored without tarp on pallets using custom hired equipment still has the largest positive net present value. Without the BCAP incentives, no feedstock supply chain configuration using purchased rather than custom hired equipment generated a positive net present value.

We investigate the (S-1,S) inventory policy under stuttering Poisson demand and exponentially-distributed lead times when demand in excess of on-hand inventory is routed to an emergency order fulfillment system. This system contains a regional stocking location (RSL), which serves two types of facilities: a set of field service locations (FSL) and an emergency stocking location (ESL). The field service locations support technical service representatives who make visits to customer sites to repair equipment. We derive both exact and approximate expressions for the mean and variance of the number of units in emergency resupply. We also estimate the probability of zero units in emergency resupply. Simulation results confirm the quality of these approximations. Later, we use a distribution with an atom at zero and a zero-truncated negative binomial distribution to approximate the shape of this distribution. The quantiles are shown to be well approximated in simulations with various settings. In particular, the approximation is excellent in the upper tail which is the portion of the distribution used to determine the target inventory level for the emergency stocking location. Finally, we develop an optimization algorithm for setting stock levels in such a system with both field service locations and an emergency stocking location. The problem is an integer programming problem with a potential non-convex objective and we explore a heuristic algorithm for solving the optimization problem. For empirical studies, we compare the results of our heuristics with PSWARM, a general purpose algorithm for such problems.

Data analysis is a process of inspecting and obtaining useful information from the data, with the goal of knowledge and scientific discovery. It brings together several disciplines in mathematics and computer science, including statistics, machine learning, database, data mining, and pattern recognition, to name just a few. A typical challenge with the current era of information technology is the availability of large volumes of data, together with ``the curse of dimensionality''. From the computational point of view, such a challenge urges efficient algorithms that can scale with the size and the dimension of the data. Numerical linear algebra lays a solid foundation for this task via its rich theory and elegant techniques. There are a large amount of examples which show that numerical linear algebra consists of a crucial ingredient in the process of data analysis. In this thesis, we elaborate on the above viewpoint via four problems, all of which have significant real-world applications. We propose efficient algorithms based on matrix techniques for solving each problem, with guaranteed low computational costs and high quality results. In the first scenario, a set of so called Lanczos vectors are used as an alternative to the principal eigenvectors/singular vectors in some processes of reducing the dimension of the data. The Lanczos vectors can be computed inexpensively, and they can be used to preserve the latent information of the data, resulting in a quality as good as by using eigenvectors/singular vectors. In the second scenario, we consider the construction of a nearest-neighbors graph. Under the framework of divide and conquer and via the use of the Lanczos procedure, two algorithms are designed with sub-quadratic (and close to linear) costs, way more efficient than existing practical algorithms when the data at hand are of very high dimension. In the third scenario, a matrix blocking algorithm for reordering and finding dense diagonal blocks of a sparse matrix is adapted, to identify dense subgraphs of a sparse graph, with broad applications in community detection for social, biological and information networks. Finally, in the fourth scenario, we visit the classical problem of sampling a very high dimensional Gaussian distribution in statistical data analysis. A technique of computing a function of a matrix times a vector is developed, to remedy traditional techniques (such as via the Cholesky factorization of the covariance matrix) that are limited to mega-dimensions in practice. The new technique has a potential for sampling Guassian distributions in tera/peta-dimensions, which is typically required for large-scale simulations and uncertainty quantifications./

Abstract: Coke drums are vertical pressure vessels used in the delayed coking process in petroleum refineries. Significant temperature variation during the delayed coking process causes the useful life of coke drums to be shortened. In order to better understand the failure mechanisms, a experimental study of elastic/plastic mechanical properties and deformation behaviors of typical coke drum materials was performed. A new biaxial thermal-mechanical material testing system has been successfully developed. Basic characterization of mechanical properties of coke drum materials is achieved through uniaxial monotonic and cyclic loading tests. In addition, strain-rate dependence and creep of coke drum materials were further experimentally investigated. Complex thermal-mechanical cyclic tests were conducted. The experimental findings help us to understand the damage mechanisms of coke drums such as bulging. In addition, experimental data serve as benchmark data to verify the predictions of the temperature dependent elastoplastic constitutive model.

The multilayer optical structure of thin film polycrystalline II-VI solar cells such as CdTe is of interest because it provides insights into the quantum efficiency as well as the optical losses that limit the short-circuit current. The optical structure may also correlate with preparation conditions, and such correlations may assist in process optimization. A powerful probe of optical structure is real time spectroscopic ellipsometry (SE) that can be performed during the deposition of each layer of the solar cell. In the CdCl2 post-deposition treatment process used for thin film polycrystalline II-VI solar cells, the optical properties of each layer of the cell change during the process due to annealing as well as to the elevated temperature. In this case, ex-situ SE before and after treatment becomes a reasonable option to determine the optical structure of CdCl2-treated CdTe thin film solar cells.CdTe solar cells pose considerable challenges for analysis by ex-situ SE. First, the relatively large thickness of the as-deposited CdTe layer leads to considerable surface roughness, and the CdCl2 post-deposition treatment generates significant additional oxidation and surface inhomogeneity. Thus, ex-situ SE measurements in reflection from the free CdTe surface before and after treatment can be very difficult. Second, SE from the glass side of the cell is adversely affected by the top glass surface which generates a reflection that is incoherent with respect to the reflected beams from the thin film interfaces and consequently depolarization if collected along with these other beams. In this research, the first problem is solved through the use of a succession of Br2+methanol treatments that smoothens the CdTe free surface, and the second problem is solved through the use of a 60° prism optically-contacted to the top glass surface that eliminates the top surface reflection. In addition, the succession of a Br2+methanol treatment not only smoothens the CdTe surface but also enables CdTe etching in a layer-by-layer fashion. In this way, it has been possible to track the optical properties of the CdTe component layer as a function of depth from the surface toward the CdS/CdTe interface in order to gain a better understanding of the film structure.In this study, ex-situ spectroscopic ellipsometry was applied first to investigate the optical properties of the TEC-15 glass substrate, and then to extract the optical properties of thin film CdTe and CdS both as-deposited and CdCl2-treated. After obtaining all the optical properties of the solar cell component layer materials, a comprehensive ex-situ SE analysis has been applied to extract the optical structure of a single thin film of CdCl2-treated CdTe, and finally to obtain the optical structure of the CdCl2 post-deposition treated CdTe solar cell.Based on the fundamental studies in this thesis, various aspects of the solar cell structure after the complicated CdCl2 treatment have been determined. In future work the role of the key parameters of CdCl2 post-deposition treatment process will be explored including: the temperature and treatment time. As a result, a correlation will be established between solar cell performance and film structure. Finally, an understanding of how solar cell structure can be optimized to achieve the highest solar cell performance may be possible through improved control of the CdCl2 post-treatment process.

Background: The current nursing shortage is a growing public concern and threatens the quality of patient care in American hospitals. Unrealistic workloads are one of the top reasons for hospital nurses' leaving the profession. Although nursing workload is extensively discussed in the literature, little is known about the influence of these workloads on physiological strain to female hospital Registered Nurses (RNs). The first objective of the study was to describe the physiological responses to workload of female hospital RNs. Three physiologic parameters'energy expenditure (EE), heart rate (HR) and work pace (WP), were measured to identify physiological response patterns over a 12-hour shift; and then response patterns of the 1st eight hours were compared to the last four hours to determine if there was a change in the physiological response to work in the later part of the shift. The second objective of the study was to examine the association between the physiological parameters and perceived workload. Fatigue and recovery factors were examined in terms of their contributions to the physiological responses to work.Methods: Demographic and fatigue data were collected from a convenience sample of 145 healthy hospital female RNs. The nurses completed a work diary, and wore a physical activity monitor for one 12-hour day shift to continuously record their HR and WP. These measures were used to calculate EE. Correlations, t tests, one-way ANOVA, repeated-measure MANCOVA, and multiple regression analyses were performed to describe the physiological response patterns to workload and the association of these physiological responses with perceived workload, fatigue, and recovery. Findings: The average energy expenditure for the 12-hour shift was 551.4 ± 323 kcal, indicating a light intensity level. The average HR over a 12-hour shift was 96.9 ± 15.8 bpm. More than one third of nurses experienced mean HRs above 100 bpm during 12-hour day shift, indicating a poor fitness between workload and functional capacity. No differences of EE intensity and HR between 8am-; 3pm and 3- 7pm were found, whereas WP intensity during 8am - 3pm was higher than that during 3 - 7pm (p = .007). Nearly 84%, 53% and 45% of the subjects experienced moderate to high level of acute fatigue, insufficient inter-shift recovery, and chronic fatigue, respectively. Perceived workload was found to be significantly predictive of WP intensity but not for EE intensity and HR. Medical-surgical unit nurses experience significantly higher perceived workload and physiological strain than those working on step-down floors.Conclusions: There is a relationship between physiological state at work and perceived workload among hospital RNs and nurses may be modifying their WP intensity to protect themselves from excessive work strain. Insufficient recovery and high levels of chronic fatigue may be the result of chronic physiological work stress. The strain of workload has implications for the nurses' health and ultimately the safety of hospital patients. Findings indicate a need for collaboration of hospital nursing administration and staff nurses to address the issues such as staffing plan, work scheduling, and individual factors related to sufficient recovery.

Fluid mixing is a challenging problem in laminar flow systems. Even in microfluidic systems, diffusion is often negligible compared to advection in the flow. The idea of chaotic advection can be applied in these systems to enhance mixing efficiency. Topological chaos can also lead to efficient and rapid mixing. In this dissertation, an approach to enhance fluid mixing in laminar flows without internal rods is demonstrated by using the idea of topological chaos. Periodic motion of three stirrers in a two-dimensional flow can lead to chaotic transport of the surrounding fluid. For certain stirrer motions, the generation of chaos is guaranteed solely by the topology of that motion and continuity of the fluid. This approach is in contrast to standard techniques. Appropriate stirrer motions are determined using the Thurston-Nielsen classification theorem, which also predicts a lower bound on the complexity of the dynamics in the flow. Work in this area has focused largely on using physical rods as stirrers, but the theorem also applies when the ``stirrers'' are passive fluid particles. In this thesis, topological chaos is theoretically and numerically investigated in lid-driven cavities and rectangular channels without internal rods. When a two-dimensional incompressible Newtonian flow is in the Stokes flow regime, the stream function satisfies the two-dimensional biharmonic equation. When the flow occurs in a lid-driven cavity with solid side walls, this equation can be solved using a method that is similar to the traditional Fourier expansion but uses an asymptotic approximation for the sum of high order terms. When the flow occurs between two infinite plates with spatially periodic boundary conditions, an exact solution in a rectangle with finite width, which represents the flow in this infinitely-wide cavity, can be obtained by using the principle of superposition. A fully developed, three-dimensional flow in a rectangular channel can be decomposed into an unperturbed Poiseuille flow in the axial direction and a lid-driven cavity secondary flow in the cross section. This model can be applied to numerically simulate either pressure-driven flow in a rectangular channel with surface grooves or electro-osmotic flow in a rectangular channel with variations in surface potential. In this dissertation, the occurrence of topological chaos in unsteady two-dimensional flows as well as steady three-dimensional flows without internal rods is demonstrated. For appropriate choices of boundary velocity on the top and/or bottom walls, there exist three periodic points in the flows that produce a chaos-generating motion. In steady flow through a three-dimensional rectangular channel, the axial direction plays the role of time and the periodic points lie on streamtubes that "braid" the surrounding fluid as it moves through the duct. When appropriate motion is applied on the boundary of the wide cavity or channel, topological chaos can also be generated in the flow. The stretching rate of non-trivial material lines in all these flows agrees with the prediction of the lower bound of topological entropy provided by the Thurston-Nielsen theorem. Ghost rod structures are found and analyzed in the lid-driven cavity and rectangular channel flows with solid side walls. The results suggest that the no-slip boundary condition on the stationary internal surfaces is one of the reasons for poor mixing in steady laminar three-dimensional flows considered previously with solid braided internal rods.

This thesis investigates efficient VLSI architectural design aspects of a digital signal processing (DSP) transceiver in high speed multi-pair wireline communication systems, such as 10 Gigabit Ethernet over copper (10GBASE-T), with the goal to reduce the hardware complexity and power consumption of various DSP components while maintaining the speed and performance requirements. The covered topics mainly include efficient far-end crosstalk (FEXT) cancellers, novel multi-input multi-output (MIMO) equalizers combined with Tomlinson-Harashima Precoding (THP), low complexity echo and near-end crosstalk (NEXT) cancellers. A novel feedforward delayed FEXT canceller in a THP based system is developed to remove FEXT as noise. Unlike conventional techniques on FEXT cancellation, the proposed FEXT canceller can mitigate the non-causal part of FEXT; thus it can achieve better cancellation performance. In addition, a modified design is developed by eliminating the feedback loops in the FEXT cancellers such that the resulting feedforward FEXT canceller is suitable for high speed applications. FEXT has been found to contain information about the symbols transmitted from remote transmitters and thus MIMO equalization technique is proposed to jointly process ISI and FEXT such that the useful information in FEXT can be utilized. It is shown that the proposed architecture overcomes the limitation of the traditional equalization schemes and can achieve a better system performance and lower hardware complexity. A computationally efficient approach for calculating the optimal tap coefficients of MIMO equalizers and cancellers is also proposed to speedup the computation. Furthermore, a practical equalization scheme which combines the MIMO equalization technique and TH precoding technique is proposed for the real application of high speed Ethernet systems. Different from existing work on MIMO equalization, the proposed scheme exactly complies with the current 10GBASE-T standard and can be easily pipelined for high speed implementation. Hardware complexity reduction schemes by utilizing the increased decision point SNR (DP-SNR) are also considered. Gigabit and multi-gigabit transceivers require very long adaptive filters for echo and NEXT cancellation. Implementation of these filters not only occupies large silicon area but also consumes significant power. This thesis considers the problems of designing cost-efficient echo and NEXT cancellers mainly from two different aspects: one is to reduce the number of taps used in these noise cancellers; the other is to reduce the word-length used to represent data in a VLSI system. First, the sparse characteristics of the echo and NEXT channel impulse responses is exploited to reduce computational cost of adaptive echo and NEXT cancellers. Second, a novel word-length reduction scheme is proposed by replacing the original input to the echo and NEXT cancellers with a finite-level signal, which is then recoded to have shorter word-length. To further reduce the complexity of these cancellers, an improved design is proposed by exploiting the property of the compensation signal. Compared with the traditional design, the proposed echo and NEXT cancellers have exact input and do not suffer from the quantization problem, and thus they are more suitable for VLSI implementation. The design issues of adaptive noise cancellers by using the proposed word-length reduction method are also considered and modified designs of the adaptive cancellers are developed to further reduce the overall hardware cost of echo and NEXT cancellers with acceptable cancellation performance. Finally, the design approach for stable pole-zero modeling of long finite impulse response (FIR) filters is proposed.

The recent manufacturing environment is characterized as having diverse products due to mass customization, short production lead-time, and unstable customer demand. Today, the need for flexibility, quick responsiveness, and robustness to system uncertainties in production scheduling decisions has increased significantly. In traditional job shops, tooling is usually assumed as a fixed resource. However, when tooling resource is shared among different machines, a greater product variety, routing flexibility with a smaller tool inventory can be realized. Such a strategy is usually enabled by an automatic tool changing mechanism and tool delivery system to reduce the time for tooling setup, hence allows parts to be processed in small batches. In this research, a dynamic scheduling problem under flexible tooling resource constraints is studied. An integrated approach is proposed to allow two levels of hierarchical, dynamic decision making for job scheduling and tool flow control in Automated Manufacturing Systems. It decomposes the overall problem into a series of static sub-problems for each scheduling window, handles random disruptions by updating job ready time, completion time, and machine status on a rolling horizon basis, and considers the machine availability explicitly in generating schedules. Two types of manufacturing system models are used in simulation studies to test the effectiveness of the proposed dynamic scheduling approach. First, hypothetical models are generated using some generic shop flow structures (e.g. flexible flow shops, job shops, and single-stage systems) and configurations. They are tested to provide the empirical evidence about how well the proposed approach performs for the general automated manufacturing systems where parts have alternative routings. Second, a model based on a real industrial flexible manufacturing system was used to test the effectiveness of the proposed approach when machine types, part routing, tooling, and other production parameters closely mimic to the real flexible manufacturing operations. The study results show that the proposed scheduling approach significantly outperforms other dispatching heuristics, including Cost Over Time (COVERT), Apparent Tardiness Cost (ATC), and Bottleneck Dynamics (BD), on due-date related performance measures under both types of manufacturing systems models. It is also found that the performance difference between the proposed scheduling approach and other heuristics tend to become more significant when the number of machines is increased. The more operation steps a system has, the better the proposed method performs, relative to the other heuristics. This research also investigates in what conditions (e.g. the number of machines, the number of operation steps, and shop load conditions) the proposed approach works the best, and how the performance of this proposed approach changes when these conditions change. When tooling resource is shared, parts can be routed to machines that do not have all the required tools. This may result in higher routing flexibility. However, research work to date in sharing of tooling resources often places more emphasis on the real-time control and manipulation of tools, and pays less attention to the loading of machines and initial tool allocation at the planning stage. In this research, a machine-loading model with shared tools is proposed to maximize routing flexibility while maintaining minimum resident tools. The performance of the proposed loading heuristic is compared to that of a random loading method using hypothetically generated single stage system models. The study result indicates that better system performances can be obtained by taking into account the resident tooling ratio in assigning part types and allocating tools to machines at the initial planning stage.

This thesis addresses problems in robustness analysis and design of linear multivariable feedback systems with several sources of modelling uncertainty. The problem of maintaining stability and performance robustness in the presence of plant uncertainty is of fundamental importance and has received considerable attention. A useful tool for such problems is furnished by structured singular value analysis. However, because the structured singular value is a complicated function of the system data and can only be calculated via a numerical optimization procedure, it is often difficult to obtain insights useful in design. The objective of this work is to develop such important insights. We first present a general analysis approach for robustness problems that may be studied using the structured singular value analysis. The first step of this approach is to identify certain important parameters which characterize how several sources of uncertainty may interact to cause robustness difficulties. The second step involves deriving bounds upon the structured singular value that explicitly display its dependence upon the plant, compensator, design specification and uncertainty description. Once these tasks are accomplished, we utilize the bounds and insights to study a class of typical multivariable design problems that are inherently difficult. We specifically investigate potential design difficulties that often arise due to the plant ill-conditioning. A robustness indicator is developed to quantify the degree of such difficulty, which is shown to depend upon the size of the plant condition number as well as its directionality properties. We further propose a loop-shaping design strategy that is useful in resolving this difficulty.