Browsing by Subject "Efficiency"

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Adiabatic Packed Column Supercritical Fluid Chromatography
(2015-12) Helmueller, Shawn
A well-known problem in supercritical fluid chromatography is the drastic decrease in chromatographic performance at temperatures above 40 C and outlet pressures below 120 bar. This phenomenon has been attributed to isenthalpic expansion and cooling of the mobile phase and poor heat transport under these temperatures and pressures. If the temperature of the fluid does not match the temperature of the column surroundings, a radial temperature gradient forms due to heat transfer between the column and the thermal environment surrounding the column. This radial temperature gradient causes a radial fluid density profile inside the column and radial distributions in important solute parameters such as diffusion coefficients and retention factors. This ultimately results in solute band broadening and a decrease in band resolution. For this reason, method development and method transfer can be complex and the pressure-temperature region near the critical point of the mobile phase is routinely avoided. A novel dual-zone still-air column heater has been developed that can be set to match the adiabatic temperature profile of the fluid inside the column as predicted by the equation of state for the fluid. As a result, the efficiency loss associated with the formation of radial temperature gradients can be largely avoided in packed analytical scale columns. For example at 60 C with 5% methanol modifier and a flow rate of 3mL/min, a 250mm x 4.6mm x 5μm Kinetex (Coreshell) C18 column began to lose efficiency (>25% decrease in the number of theoretical plates) at outlet pressures below 140 bar in a forced air (non-adiabatic) thermal environment. The minimum outlet pressure was decreased to 120 bar in a traditional isothermal still air (near-adiabatic) column heater and to 100 bar in the new near-ideal adiabatic still-air heater before observing excess efficiency loss. Decreasing the minimum outlet pressure from 140 bar to 120 bar and 100 bar resulted in a corresponding increase in the retention factor for n-octadecylbenzene from k=3.6 to k=5.5 and k=16.9 respectively. Simulations for the relative effect of axial gradients in the retention factor on the apparent plate height suggest that in a perfectly adiabatic environment, negligible efficiency loss should be observed. As a result, efficient separations can be carried out at higher temperatures and lower outlet pressures compared to traditional column thermostatting techniques by operating the SFC column adiabatically.
Circuit Design and Modeling Techniques of On-chip Power Delivery Modules
(2015-01) Paul, Ayan
Designing an efficient power delivery network is one of the most important aspects of modern low-power microprocessor designs. Power delivery network consists of off-chip converters, wires/bumps to route power and ground signals from off-chip converters to inside the chip, on-chip converters, and on-chip power grid. Parasitic resistance and inductance of routing wires and package cause IR noise and resonant supply noise in the supply line, whereas parasitic capacitance of the power and ground lines results in a significant increase in the charging and discharging time of the supply lines during transients of dynamic voltage and frequency scaling (DVFS). DVFS, which scales supply voltage depending on the performance requirement of the processor, thereby saving dynamic power dissipation, has become an integral part of today's microprocessor. However, because of large IR noise to route off-chip power and ground signals and large off-chip component count, per-core DVFS in a many-core processor cannot be supported with off-chip converters. We present design techniques to tackle non-idealities of the power delivery networks. At the same time, we propose on-chip power delivery solutions. We present a circuit technique based on staggering activation of cores in order to mitigate first-droop noise from the supply network. From our 65nm bulk CMOS test-chip, we measure a 12.7% improvement in resonant supply noise of a 2-core processor using our proposed noise reduction technique. In order to reduce IR noise of the power delivery network, we propose a switched capacitor step-up converter. The converter built in 32nm SOI CMOS process shows a 45% improvement in IR noise of the supply line. For faster charging of the supply line, we build a step-down converter in 32nm SOI CMOS process, and measured 5x reduction in the charging time of the supply network. Using a 32nm SOI CMOS process, we build an on-chip switched capacitor DC/DC converter, capable of supporting two outputs with the help of time division demultiplexing. Finally, we propose two power delivery system using two industry-standard state-of-the-art power delivery units (fully integrated voltage regulators and low dropout regulators), and compare the power consumption of the entire system using random and minimum power scheduling techniques.
Essays on the economics of food production and consumption in Vietnam.
(2008-12) Vu, Linh Hoang
This study aims to provide an in-depth understanding of the economics of food production and consumption in Vietnam. Specifically, the study is comprised of five essays, covering several aspects of agriculture and food consumption in Vietnam. The first essay studies agricultural productivity growth in Vietnam, using province-level data. It concludes that total factor productivity (TFP) growth in agriculture contributed greatly to Vietnam's agricultural success after it adopted reform policies. However, TFP growth has slowed in recent years, despite significant output growth. The second essay examines the productive efficiency of rice farming households in Vietnam, using two methods, Data Envelopment Analysis (DEA) with bootstrap and Stochastic Frontier Analysis (SFA). It points out that there is variation in efficiency estimates across regions in Vietnam. Moreover, technical efficiency is significantly influenced by primary education and regional factors. The third essay estimates household food demand parameters in Vietnam, based on a recent household survey conducted in 2006. The results indicate that that food consumption patterns in urban and rural areas, and across regions and income groups, are quite different. This implies that targeted food policies should be formulated based on the specific food demand patterns of those groups. Socio-economic factors such as household size and composition, as well as the age of the household's head and education, have sizeable and statistically significant effects on food consumption. The fourth essay focuses undernutrition and food security in Vietnam. The income elasticity of calorie consumption is estimated using both parametric and non-parametric regressions. The finding of positive and significant calorie-expenditure elasticity implies that income growth can alleviate undernutrition Finally, the fifth essay examines the impacts of rising food prices on poverty and welfare in Vietnam. Increases in food prices raise the real incomes of those selling food, but make net food purchasers worse off. Overall, the net impacts on an average Vietnamese household's welfare are positive. However, the benefits and costs are not evenly spread across the population, so some households are made better off while the others are worse off.
Impact of technical assistance and microcredit among rural households in El Salvador
(2013-02) Diaz Malpica, Jose Ygnacio
There is an increased interest in knowing whether the provision of nonfinancial, technical services along with microcredit has a positive impact on the performance of borrowers. The combination of these services may help poor households improve their economic performance. Yet, evidence proving this proposition is scarce and results are mixed. This lack of formal evaluation is often a consequence of these services being part of integrated approaches, making the assessment of their impact difficult to disentangle from the sole impact of microcredit. This dissertation provides evidence of joint productivity impact from microcredit and technical assistance received during 1997-1999 by rural household clients of a major microcredit institution in El Salvador. We find that the use of credit has positive effects on farm productivity. It is estimated that for every 1,000 colones of additional credit received there is a 9 percent increase in the value of farm output. These results are at the high end of the range of productivity impact reported in previous studies. When technical assistance is introduced along with credit there is also a positive impact in household productivity. In addition, we find that the pattern of consumption of these two services matters. Households with repeated loans experience smaller changes in productivity than households that borrow for the first time. It is unclear why these patterns of consumption impact productivity in different ways. However, we find that credit and technical assistance contribute to productivity through different paths: increased technical efficiency, technology adoption, and economies of scale. The role of credit and technical assistance in contributing to these productivity elements is assessed through the analysis of the households' production possibility frontier. Technical efficiency improved during these years, mainly from the effect of technical assistance. In addition, we conclude that adoption of new technologies was promoted by both credit and technical assistance. There is also evidence that these households experience increasing returns to scale. Technical assistance may have contributed to the generation of these economies of scale by increasing farmers' skills. Credit may have helped farmers to expand their input use and take advantage of the economies of scale.
Improving the efficiency of a ceria reduction-oxidation cycle through the choice of operating conditions and ceria morphology
(2014-05) De Smith, Robert Michael
Pathways for improving the efficiency of ceria-based thermochemical cycling for solar-driven fuel production are investigated. First, the operating conditions of an isothermal CO₂ splitting cycle are optimized to improve process efficiency. The optimum conditions are a sweep gas flow rate of 150 mL min-1 g-1, a CO₂ flow rate of 50 mL min-1 g-1, a reduction time of 100 s, and an oxidation time of 155 s. A quasi-equilibrium model is developed to predict the rates of ceria reduction and oxidation. Finally, a new ceria morphology, wood templated ceria, is used to improve the heterogeneous oxidation reaction rates by maintaining a high surface area when exposed to the extreme temperatures required for ceria reduction. Wood templated ceria performs well at reduction temperatures up to 1400 °C, reaching peak CO production rates of 9 mL min-1 g-1, but rates decrease due to sintering when it is reduced at 1500 °C.
Improving the Safety and Efficiency of Roadway Maintenance Phase I: Developing a Robotic Roadway Message Painter Prototype
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-05) Rosandich, Ryan G.
A large-scale prototype for a robotic roadway message painter was developed, built, and tested. The system is a gantry-style robot capable of painting a four-by-eight-foot area and is based on off-the-shelf linear motion components, readily available motion control hardware, and commercial operator interface software. The system is mounted on a modified trailer that can be manually rolled around for positioning or towed behind a vehicle. The system is equipped with a standard automatic paint head and airless paint pump. Software was developed for the system that enables it to paint a variety of characters and symbols on the roadway. An operator interface was also developed that allows an operator to easily select the painting operation to be conducted and to monitor and control the actual painting process. The software resides in a laptop computer that communicates with the robotic painting system in real-time using a dedicated Ethernet connection. The system was used to determine the feasibility of painting with or without stencils and to determine many design parameters for the eventual development of a commercially viable system for painting symbols and messages on roadways. It is expected that the system will eventually enable states, counties, and municipalities to improve the safety, productivity, and flexibility of their pavement marking operations.
Improving the Safety and Efficiency of Roadway Maintenance Phase II: Developing a Vision Guidance System for the Robotic Roadway Message Painter
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2013-02) Rosandich, Ryan G.
Repainting existing roadway markings (turn arrows, STOP messages, railroad crossings, etc.) is an important task for transportation maintenance organizations. MnDOT estimates that over 75% of symbol and message painting is the repainting of existing markings. It would be extremely valuable for an automated painting system to have a vision guidance capability whereby an existing mark could be repainted accurately with little operator input. In this project a vision system was developed that is capable of identifying existing painted pavement markings and determining their dimensions, location, and orientation. Techniques were also developed whereby this information could be used to determine the location of the marking in the workspace of a painting robot to enable it to accurately repaint the marking. The vehicle-mounted robotic painter is still being built and tested, so final test results will not be available until the vision system can be completely integrated with the painter, and the two can be tested together. The accuracy of the projection produced using the techniques developed in this project would suggest that the final system will be capable of repainting pavement markings almost exactly where they appear on the roadway. Expected benefits of the deployment of a vision-guided robotic painting device include improved operator safety, improved productivity, and improved flexibility in roadway marking and repainting operations. Eventual users of a device using this technology could be city, county, state, and federal government agencies and private companies or contractors.
Modeling, Analysis, and Experimental Investigation of a Variable Displacement Linkage Pump
(2015-07) Wilhelm, Shawn
Hydraulic power systems offer a robust, compact, and flexible method of power transmission and are used widely in both industrial and mobile applications. While 2% of the energy consumed in the US passes through hydraulic systems, less than half of it does any useful work largely due to the use of inefficient flow control valves. Variable displacement pumps offer a method of delivering the required flow to an actuator without suffering the losses associated with a flow control valve. However, current variable displacement pumps exhibit poor efficiency at low displacement because their primary sources of energy loss are largely independent of displacement. Here, a novel adjustable linkage is proposed as the driving mechanism of a variable displacement pump. The linkage is constructed such that the pumping piston returns to the same top-dead-center position at all displacement, and can also achieve zero displacement. As a result of these features, the pump displacement is infinitely variable, and the unswept volume is remains constant at all displacements. By using pinned joints rather than sliding joints, the majority of the energy losses scale with output power resulting in a pump that is efficient over a wide range of operating conditions. In this thesis, a complete model of a variable displacement linkage pump is developed. A method of constructing the adjustable sixbar mechanism and the possible embodiments is presented. A new solution rectification technique is developed providing a robust method of generating valid linkages that is generally applicable to other mechanisms. The kinematics of the mechanism are then presented to describe the motion of the links and output piston. A kinetostatic model of the mechanism provides a means of determining the internal mechanical energy losses. A non-linear model of the bearing friction augments the model, but requires numerical methods to solve, and increases computational complexity. A dynamic model of the pumping cylinders and pump manifold provide a means of determining the fluid behavior of the pump including output flowrates and pressures. These models are coupled to create a complete understanding of the variable displacement linkage pump. The model is designed to be predictive and computationally inexpensive for use in multi-objective optimizations. As such, no experimentally determined performance coefficients are required. No model of this level of completeness exist for linkage driven pumps, variable displacement or otherwise. Two prototype pumps are presented and used to validate the models. A single cylinder pump is used to validate the mechanical energy loss model but was limited to low pressure operation due to large torque variations. Close agreement is demonstrated between the model and experiment. The model predicts a pump efficiency greater than 90% at displacements as low as 15% if roller bearings are used in the pin joints. To validate this prediction, a multi-cylinder prototype which uses roller bearings in the joints is designed. The kinematic and mechanical energy loss models are coupled to a basic pumping model for use in a multi-objective genetic algorithm to optimize the mechanism. The resulting pump demonstrates close agreement between the model and experimentally measured shaft torque and mechanical energy loss at various pressures, displacements, and input shaft speeds. However, out-of-plane deflection of the mechanism reduced the piston displacement and altered the trajectory reducing pump output. The true temporal piston position is measured and used as an input to the dynamic fluid model. The predicted and experimentally measured cylinder pressures demonstrate the effectiveness of the model at predicting the dynamic behavior of the fluid end of the pump. It is shown that the models can accurately capture the physics of the pump without using tuning parameters or experimentally determined coefficients over a wide range of operating conditions. It is recommended that single shear linkage arrangements are avoided in future designs to increase the mechanism stiffness and improve performance. The variable displacement linkage pump offers the opportunity for high efficiency flow control at a wide range of operating conditions due to the nature of the energy loss mechanisms scaling with the output power. The flexibility of the driving sixbar mechanism allows for the optimization of the architecture for particular applications and the presented model provides a means of predicting performance.
Non-Linear Characterization and Control of Interior Permanent Magnet Synchronous Machines
(2022-06) Chandrasekaran, Visweshwar
The dissertation will present a systematic process for advanced characterization and control of a popular class of synchronous machines called Interior Permanent Magnet Synchronous Machines (IPMSM). The IPMSM machine exhibits several non-linear properties such as flux saturation and cross-coupling to name a few. Knowledge of the non-linear properties of the machine requires access to advanced design tools such as Finite Element Analysis (FEA) which may not be easily accessible within industries that do not design or manufacture these motors. The performance and efficiency of these motors are reliant on precise knowledge of advanced parameters. This body of work develops into two focus areas - experimental characterization of the IPM machine and Maximum Torque Per Amp (MTPA) based control of the machine using the experimental data. Firstly, the dissertation proposes an experimental method for extraction of Direct (D) and Quadrature (Q) axis flux linkages of the IPMSM considering both saturation and cross-magnetization effects over the entire range of the machine’s rated current. A key constraint placed is a standstill estimation of the machine in its targeted application. A novel method for generating the current pulse pattern is proposed which enables the automatic creation of 2D Flux Linkage maps of the motor using any standard controller. Analytical expressions are developed to determine the constraints for pulse pattern considering the power converter-based current control and minimizing rotor movement during the test. The flux maps obtained experimentally are seen to match the FEA-generated equivalent within an acceptable tolerance of error. The second focus area consists of developing MTPA control schemes that address practical issues such as complex offline/online calculations/excitation methods seen in classic literature. Initial research focused on developing an offline numerically efficient MTPA trajectory generation that uses FEA data to create a torque profile related to the optimal solution of net space vector current and corresponding current angle. Further research removed the dependency of the offline MTPA trajectory generation scheme on the FEA dataset by developing a method that utilizes simple motor datasheet parameters to get an initial non-efficient trajectory. This trajectory is fine-tuned during motor operation (online) via a novel discrete extremum-seeking state controller. While the offline method is shown to execute with minimal computational demand in a 32-bit MCU controller, the online method is shown to have comparable real-time performance while achieving equivalent MTPA tracking accuracy without introducing electrical or mechanical instability. Both methods have been implemented in a classic Field Oriented Control (FOC) scheme for the IPM motor using a standard 2-level Voltage Source Inverter (2L-VSI) prototype supplied from a 650V DC power supply. The methods have been experimentally verified on a 3 HP dynamometer with custom-built data acquisition instrumentation as well as software. Experimental results show good correspondence to simulations thus proving the effectiveness of the proposed methods.
Planning for a Sustainable Future: Inver Grove Heights Efficient City Fleet
(2018) Hillstrom, Ally
The objective of this paper is to identify actions the City of Inver Grove Heights can take to increase the fuel efficiency of their vehicle fleet, reduce fleet management costs, and reduce fleet emissions. This paper begins with an overview of the City of Inver Grove Heights existing fleet management conditions including fleet composition, expenses, emissions, and replacement process. The next section of this report reviews fleet management frameworks currently followed by government agencies. Next, fleet management case studies are presented of two local government organizations in Minnesota based on defined criteria. Each case study showcases how local government organizations have implemented fleet management practices included in the previous fleet management framework section to also achieve similar fleet management goals as defined by the City of Inver Grove Heights. Additional information regarding the organizations' fleet management policies and policy outcomes are included. Drawing from transferrable lessons learned from a literature review of government fleet management frameworks and case studies collected through interviews, best management practices and policy options are presented for the City of Inver Grove Heights updated fleet management process and are evaluated based on a cost-benefit analysis. This paper concludes with final recommendations for the City of Inver Grove Heights to increase the fuel efficiency, reduce fleet management costs, and reduce vehicle emissions based on this multi-method analysis. The Cost Benefit Analysis presented in this paper suggests that the greatest impact on all three goals could be achieved by reducing inefficient driving behavior (Fig. 16.1 through 16.4). It is recommended the City continues to collect more comprehensive vehicle use data to identify the cause of inefficient driving behaviors and to identify strategies to potentially reduce inefficient driving behavior, such as through employee education.
The state of subsistence agriculture in Ethiopia: sources of output growth and agricultural inefficiency.
(2009-06) Bachewe, Fantu
Agriculture dominates the Ethiopian economy, accounting for about 50 percent of its GDP and 82 percent of its employment. However, the sector has always performed poorly; about one-half of the rural residents in Ethiopia live below the national poverty line, and the rural population is endowed with few and poorly provided social amenities. Sectoral-level data shows that the farmers in Ethiopia use little modern inputs and output per hectare is low. With rural population increasing at a fast pace, land holdings have been increasingly fragmented. Although fertilizer is the most widely used modern input, application rates are abysmally low, even by Sub-Sahara Africa standards. Use of improved seeds and pesticides is almost nonexistent. Among a group of other comparable countries (Sub-Saharan Africa, developing, the poorest five, and Ethiopia's neighboring countries) the Ethiopian agriculture performed the poorest. If Ethiopian farmers were to achieve the average yield levels reported in these comparable countries it would at least be self-sufficient in cereals production; other scenarios show output could grow substantially. Descriptive and comparative analysis conducted on the agroecologic zones included in 5 out of 6 Ethiopian Rural Household Surveys (ERHS) conducted between 1994 and 2004 shows that crop yields increased marginally while the area under cultivation expanded more rapidly. Moreover different zones tended to specialize in one or two crops. Household data indicates that subsistence farmers suffer from shortage of credit, have little exposure to modern production know-how, and most importantly suffer from shortage of rainfall that frequently turns to drought. In a country with ample water resources and where a large majority the population is engaged in rain-fed agriculture, which has become increasingly risky due to persistent drought, will be key to improving the lives of most Ethiopians. In addition to a descriptive and comparative analysis, this study used panel data from ERHS to statistically analyze the sources of output growth and technical efficiency in subsistence agriculture in Ethiopia. Assessing the sources of increased production, and examining the extent and sources of measured production inefficiencies can reveal options for ameliorating the bleak conditions confronting Ethiopian agriculture. A stochastic frontier analysis (SFA) was used to assess the variation in technical efficiency in addition to accounting for the sources of growth in agricultural output. There are indications that most of the increase in output in such subsistence agriculture was attained by increased use of traditional inputs, notably the amount of rainfall, the area and quality of cultivated land, and the numbers of oxen and hoes. By contrast, the rate of fertilizer application contributed the least for increase in output. However, participation in a nationally conceived extension program contributed significantly to output gains. Each agro-ecological zone included in the study gained from Hicks-neutral technological improvements during the study period. The average level of farming efficiency for the surveyed farmers across all the years was 0.4, indicating that most of the farmers were less than one-half as efficient as those producing on the frontier. Farm households' level of farming efficiency is improved by reducing labor bottlenecks and increased education. Households that have diversified risk from plots that are located sufficiently apart appear more efficient.
Striking A Balance Between Psychometric Integrity and Efficiency for Assessing Reinforcement Learning and Working Memory in Psychosis-Spectrum Disorders
(2021-06) Pratt, Danielle
Cognitive deficits are well-established in psychosis-spectrum disorders and are highly related to functional outcomes for those individuals. Therefore, it is imperative to measure cognition in reliable and replicable ways, particularly when assessing for change over time. Notably, despite revolutionizing our measurement of specific cognitive abilities, parameters from computational models are rarely psychometrically assessed. Cognitive tests often include vast numbers of trials in order to increase psychometric properties, however long tests cause undue stress on the participant, limit the amount of data that can be collected in a study, and may even result in a less accurate measurement of the domain of interest. Thus, balancing psychometrics with efficiency can lead to better assessments of cognition in psychosis. The goal of this dissertation is to establish the psychometric properties and replicability of reinforcement learning and working memory tasks and determine the extent to which they could be made more efficient without sacrificing the psychometric integrity. The results provide support that these tests of reinforcement learning are appropriate for use in studies with only one time point but may not currently be appropriate for retest studies due to the inherent learning that occurs during the first time performing the task. The working memory tasks are ready for use in intervention studies, with the computational parameters of working memory appearing slightly less reliable than observed measures, but potentially more sensitive to detecting group differences. Lastly, these reinforcement learning and working memory tasks can be made 25%-50% more efficient without sacrificing reliability and optimized by focusing on items yielding the most information. Altogether, this dissertation provides guidance for using reinforcement learning and working memory tests in studies of cognition in psychosis in the most appropriate, efficient, and effective ways.
Study of Active Valve Timing on Efficient Hydraulic Piston Motor Operations
(2016-08) Tian, Hao
Valve timing is critical to the performance of hydraulic piston motors and pumps. With non-optimal valve timing, the pressure differential across the valve during a valve opening or closing can be significant, causing transitional throttling loss and reducing the energy efficiency. The goal of this thesis is to provide a fundamental understanding of the role of valve timing and propose a viable active valve solution for better efficiency of hydraulic pumps and motors. Previously, researchers have proposed a variety of valve timing models based on analytical modeling, numerical simulation, and optimization. However, many critical questions, such as the relationship between the valve timing and throttling energy loss, the meaning of the valve timing optimality, and the influence of the fluid compressibility with entrained gas, have not been fully answered. Prior work on valves with active timing have focused on reducing the valve transition time, leakage, and dead volume. The cylindrical rotary valve architecture has been found to be a promising solution, provided that the leakage issue is solved. In this research, a new two-phase analytical valve timing solution, a complete active motor-valve numerical model, a prototype cylindrical rotary valve, and a novel fluid compressibility experiment have been developed. Results have shown that the analytical valve timing solution is capable of capturing the trade-offs between throttling energy loss and output piston work. A full model of a motor was used to optimize valve timing for a specific operating condition. The numerical model was validated experimentally, where a prototype active rotary valve was integrated into a commercial pump. A rectified bulk modulus model was derived from a novel mass transfer experiment to determine the compressibility of oil with entrained gas based on an optical bubble size measurement. The contributions of the thesis are: (1) the validated analytical and numerical models that allow finding the optimal valve timing as a function of the operating conditions, (2) a new active valve architecture that enables variable valve timing motor/pump, and (3) a rectified fluid compressibility model based on a lumped interfacial mass transport equation that predicts the effective fluid bulk modulus dynamically.
User inequity implications of road network vulnerability
(Journal of Transport and Land Use, 2010) Jenelius, Erik
An important purpose of the road transport system is to allow people to commute in efficient and reliable ways. For various undesired reasons, however, link capacities are sometimes reduced or links are closed completely. To assess and reduce the risk of such events, a key issue is to identify road links that are particularly important, i.e. roads where disruptions would have particularly severe consequences. This paper presents a method for incorporating user equity considerations into a road link importance measure. As a complement to measuring the total increase in vehicle travel time, we also measure the disparity in the distribution among individual users. These two components are combined to form an equity-weighted importance measure. We study the properties of this measure both analytically and in a full-scale case study of the Swedish road network. A main result is that increasing the weight put on the equity aspect transfers importance from the main roads to smaller local roads. The use of the measure in transport policy and planning is discussed.
Utilizing principal-agent theory and data envelopment analysis to examine efficiency of resource utilization in undergraduate education for public and private non-profit four-year research universities.
(2012-08) Blalark, Frank J.
Utilizing a principal-agent model as a heuristic framework and data envelopment analysis as an analytical framework, this study examined relative efficiencies and resource utilization of U.S. Carnegie 15 (very high research activity) and 16 (high research activity) public and private non-profit four-year research universities in the year 2007/08 measured against baccalaureate degree production and graduation rate efficiency. The empirical findings reveal that, on average, overall technical inefficiency for all sets of research universities is primarily attributed to managerial decisions rather than failure to operate at most productive scale size. The results for public Carnegie 15 research universities (PCRU-15s), on average, show that resource utilization is better when measured against baccalaureate degree production than against graduation rate efficiency as indicated by LPTIE scores for all PCRU-15s corresponding with baccalaureate degree production (LPTIE % = 14.22) and graduation rate efficiency (LPTIE % = 22.65). The results for public Carnegie 16 research universities (PCRU-16s), on average, show that resource utilization is better when measured against graduation rate efficiency than against baccalaureate degree production as indicated by LPTIE scores for PCRU-16s corresponding with baccalaureate degree production (LPTIE % = 44.54) and graduation rate efficiency (LPTIE % = 40.58). Comparing the magnitude of LPTIE scores for private non-profit Carnegie 15 research universities (PNCRU-15s) corresponding with baccalaureate degree production (LPTIE %= 8.65) and graduation rate efficiency (LPTIE %= 10.69), results indicate that managerial decisions for PNCRU-15s, on average, are such that resource utilization is better when measured against baccalaureate degree production than against graduation rate efficiency. Consistent with private non-profit Carnegie 15 research universities, the magnitude of LPTIE scores for private non-profit Carnegie 16 research universities (PNCRU-16s) corresponding with baccalaureate degree production (LPTIE %= 8.53) and graduation rate efficiency (LPTIE %= 13.53), results indicate that managerial decisions for PNCRU-16s, on average, are such that resource utilization is better when measured against baccalaureate degree production than against graduation rate efficiency.
What Theories Are Made Of: How Industry and Culture Shaped Maxwell's Theories of Electromagnetism
(2021-03) Lazaroff-Puck, Cameron
James Clerk Maxwell's theories of electromagnetism are uniquely Victorian products. Maxwell and his physics have traditionally been viewed as aloof and disinterested, dating to the mid-to-late-19th century, but not party to the cultural, industrial, political, economic, and environmental turmoil of the era. This dissertation examines often ignored corners of Maxwell's electromagnetic theories and those of his successors to demonstrate that they were shaped by the technologies of their time. These technologies, steam engine governors, capacitors, and undersea telegraph cables are each, in their own way, responsible for the varying forms taken by Maxwellian electromagnetic theory. Each of these technologies also has its own history. These histories connect these technologies and thus Maxwellian theory to the newly emerging concept of efficiency, as well as the colonialism, economics, religion, and ecology of the British Empire. Governors, capacitors, and submarine telegraph cables serve as a historiographical bridge, allowing for the exploration of how empire-wide forces shaped the minutiae of Maxwellian electromagnetic theory.

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