998 research outputs found
Institutional Barriers to Technology Diffusion in Rural Africa
This paper analyzes the connection between informal insurance institutions in rural Africa and the adoption of new technologies. We model two linked games -- a community risk-sharing game and an old-age insurance game -- and analyze the multiple equilibria that arise. We provide a numerical example that indicates that informal insurance institutions may put a downward pressure on the adoption of new technologies.Research and Development/Tech Change/Emerging Technologies,
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Classroom exercise: Intro to Mechanical and Industrial Engineering
This classroom exercise was developed for Introduction to Mechanical and Industrial Engineering; Engineering Sustainability: Energy and the Environment. This is a freshman class with a class size of about 200. It is intended to get students to think critically about energy in the economy; to recognize the power of technological change; and to inspire them to work toward solving climate change
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Syllabus: Introduction to Mechanical and Industrial Engineering
Student teams will explore engineering analysis and design under the theme of Engineering Sustainability: Energy and the Environment, incorporating economics, environmental impacts, and social concerns. ENGIN 113 is intended to introduce students to the fields of Mechanical Engineering and Industrial Engineering, and to provide students with important skills that they will need to be successful in college and the professional world. The specific course objectives are to: Develop effective teamwork skills, including peer- and self-evaluation. Practice critical thinking and engineering problem solving. Take a systems approach to design, incorporating economics, environment, and social concerns Develop information literacy. Communicate technical material clearly to a broad audience. Demonstrate competency in computer applications, including Creo and Excel. Complete two projects incorporating some key skills from Mechanical Engineering and Industrial Engineering
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A just energy transition requires research at the intersection of policy and technology
The current energy system, in the US and around the world, is rife with inequities. The coming energy transition to a low carbon world has the potential to right some of these; but, without intention, it is more likely to perpetuate the current inequities. Enabling a just energy transition will require multiple categories of action, including fair policies and regulations; data and metrics; and knowledge generation. I focus on this last point, and particularly research at intersection of energy technology and social equity
The electrical properties of pure and doped nanocyrstalline cerium oxide
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997.Includes bibliographical references (p. 41-42).by Erin Baker Lavik.M.S
Social Information Processing and Emotion Regulation: Relationships with Attachment and Social Competance in At-Risk Preschoolers
A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Erin R. Baker on July 12, 2011
Enhancing Osseointegration of Orthopaedic Implants with Titania Nanotube Surfaces
Introduction: As joint arthroplasty surgical procedures increase annually, the development of new strategies, including novel materials and surface modifications, to attain solid bone-implant fixation are needed to increase implant terms of service. In this study, we evaluate two morphologies of titania nanotubes in both in vitro and in vivo experiments to quantify osseointegrative potential and material-level biocompatibility.
Materials and Methods: Samples were prepared via an electrochemical etching process. Two different titania nanotube (TiNT) morphologies were produced, Aligned and Trabecular. For the in vitro experiment, Sprague Dawley (SD) rat marrow-derived bone marrow cells (BMC) were seeded on samples. Alkaline phosphatase (ALP) activity, osteocalcin (OC) expression, expression of relevant genes as well as cell attachment and morphology were assessed. In the first in vivo experiment, Kirschner wires were implanted unilaterally into SD rat femora with a TiNT-etched or unmodified (Control) implant. General health assessments and weekly body weights were recorded. At a 12-week endpoint, hematologic, systemic metal ion, and histologic analyses were performed. For the second in vivo experiment, Kirschner wires were implanted bilaterally into SD rat femora, with a TiNT-etched implant in one femora and unmodified (Control) implant as an internal control. At 4- and 12-week endpoints, femora were assessed via biomechanics, undecalcified histology, micro-computed tomography (ÎĽCT), and backscattered electron imaging (BEI) to characterize de novo bone formation.
Results: In vitro experiments demonstrated BMC attachment and differentiation into osteoblasts as well as greater ALP activity, OC expression, total cell counts, and gene expression (of Col1a1, IGF-1, and osteonectin) on TiNT surfaces versus Controls. Cells on TiNT-etched substrates were smaller in diameter and more eccentric than Controls. In the first in vivo experiment, there were significant differences in body weight between groups at Weeks 9 and 11. There were no significant differences in red or white blood cell function between TiNT groups and Control. Aluminum levels in the lungs were significantly greater in the Trabecular TiNT group compared to Control. Histologic analysis showed significantly fewer granulocytes and neutrophils in the distal region of Trabecular TiNT-implanted femora as well as significantly fewer foreign body giant/multinucleated cells and neutrophils in the midshaft region of Aligned TiNT-implanted femora versus Controls. In the second in vivo experiment, at 12 weeks, µCT analysis showed TiNT implants generated greater bone formation than Controls. Histologic analysis demonstrated 1.5 times greater bone-implant contact in TiNT groups than Controls at 12 weeks. TiNT groups exhibited 1.3 to 3.7 times greater strength of fixation than Controls during pull-out testing.
Discussion and Conclusions: In vitro data confirmed BMC attachment and differentiation into osteoblasts as well as osteoblastic phenotypic behavior. A clinically-relevant in vivo model of femoral intramedullary fixation, showed increased bone formation and quality in femora implanted with TiNT-etched implants versus Controls. A second in vivo study showed that TiNT surfaces do not generate systemic effects and may beneficially modulate the periprosthetic inflammatory environment
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The Sustainability Of Decarbonizing The Grid: A Multi-Model Decision Analysis Applied To Mexico
Mexico recognizes its vulnerability to the effects of climate change, including sea level rise, increasing average temperatures, more frequent extreme weather events and changes to the hydrological cycle. Because of these concerns Mexico has a vested interest in developing sustainable strategies for mitigating climate change as it develops its electricity grid. In this study, we use a set of sustainability criteria to evaluate a number of model-derived pathways for the electricity grid aimed at meeting Mexico\u27s climate goals. We use a multi-step approach, combining pathways from multiple large scale global models with a detailed electricity model to leverage geographic information into our multi-criteria sustainability analysis. We summarize the overall ranking of each expansion plan with the use of the weighted sum method. We find that the expansion plans with more than 20% of energy coming from carbon capture and storage (CCS) technologies tend to be less sustainable. While CCS technologies have low GHG emissions, they have high air pollution and water-use and require the development of extensive pipeline networks. In particular, these CCS characteristics pose concerns from an environmental justice perspective as high air pollution and water-use can significantly effect local communities: the plan with the most CCS has an extra 14 kg/GWh of weighted air pollution emissions and 199,000 liters/GWh of weighted water use compared to the plan with the most renewables. This analysis provides novel insights on tradeoffs that decisions makers must consider when looking at different sustainable development options to reach long term climate goals
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A perspective on equity implications of net zero energy systems
We present examples of energy inequity, in both the current system and in potential net zero systems, and lay out some research needs in order to center equity in the study of net zero energy systems.
•Our current energy systems are inequitable across several dimensions.
•We must recognize and address barriers to a just and equitable net zero energy system.
•We highlight inequities in energy burden and energy insecurity; health consequences of the energy system; and decision making power.
•There is a need to define, quantify, and explicitly model equity outcomes in net zero systems.
•There is a need to better understand the equity impact of existing policies and programs.
•Energy systems researchers must include voices from marginalized communities
Finding common ground when experts disagree: robust portfolio decision analysis
We address the problem of decision making under “deep uncertainty,” introducing an approach we call Robust Portfolio Decision Analysis. We introduce the idea of Belief Dominance as a prescriptive operationalization of a concept that has appeared in the literature under a number of names. We use this concept to derive a set of non-dominated portfolios; and then identify robust individual alternatives from the non-dominated portfolios. The Belief Dominance concept allows us to synthesize multiple conflicting sources of information by uncovering the range of alternatives that are intelligent responses to the range of beliefs. This goes beyond solutions that are optimal for any specific set of beliefs to uncover defensible solutions that may not otherwise be revealed. We illustrate our approach using a problem in the climate change and energy policy context: choosing among clean energy technology R&D portfolios. We demonstrate how the Belief Dominance concept can uncover portfolios that would otherwise remain hidden and identify robust individual investments
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