A Life Cycle Assessment and Economic Analysis of Wind Turbines Using Monte Carlo Simulation

The United States depends heavily on nonrenewable fossil fuels to generate electricity. Using renewable energy sources, such as wind, could reduce air emissions and fossil fuel dependency. Previous studies have examined the life cycle costs and environmental impacts of using wind to generate electricity, but results have varied due to inconsistent modeling assumptions. This research uses Monte Carlo simulation to conduct an economic payback analysis and life cycle assessment of 11 modern, utility-scale wind turbines. Hourly meteorological data was used to evaluate 239 U.S. locations. For each location, the wind turbine with the shortest median payback period was assumed to be the economically preferred turbine model. This simulation demonstrates that variance in the model output is primarily caused by differences in location-specific climate data (wind speed, air density), Depending on the location, the median economic payback periods ranged from 2 to 132 years, 41% of the locations had median payback periods less than 10 years, and 63% less than 15 years, Considering a typical turbine lifespan of 15-30 years, wind turbines are not economically viable at all locations, At locations with favorable wind resources, wind turbines are likely to be superior to electricity production using natural gas or coal, For the preferred wind turbine, the median life cycle energy intensities at all 239 locations ranged from 0,05-0,54 (KWh energy inputs/KWh outputs), compared to 2,3 for natural gas and 2,6-3,5 for coal-fired electricity generation, The median CO2 (eq) intensity values range from 13-156 g-CO2 (eq)/kWh for the preferred wind turbine, compared to 585 g-CO2 (eq)/kWh for natural gas and 757-1042 g-CO2 (eq)/kWh for coal-fired power plants, SOx and NOx intensity values range from 0.04-0.50 g-SOx/kWh and 0.05-0.66 g-NOx/kWh for the preferred wind turbine

Roadmap to Reconciliation II: Ruminations on the Need for Integrity in Intellectual Interfaith Engagement

This article builds on the framework for a law school-based academic center for Jewish-Muslim engagement laid out in our previous work, Roadmap to Reconciliation. In this follow-up essay, we outline standards, or ground-rules, for the individuals and institutions engaged in academic interfaith discussions of the kind that would occur in our proposed Center. Chief among these considerations is the need to respect the integrity of each respective faith tradition involved in such conversations. We argue for an interfaith dialogic modeled on the insights of Rabbi Joseph B. Soloveitchik, and discuss how his reflections on the potentials and risks of interfaith engagement can be helpful in setting standards for our proposed Center for Jewish-Muslim Engagement. By offering examples of integrity-rooted interfaith approaches to practical issues in the field of Jewish-Muslim engagement, and by providing a fresh look at new frontiers for intellectual collaboration between Jewish and Muslim scholarship, we further extol the virtues and the need for a path-breaking and principled research initiative in this field

Roadmap to Reconciliation: An Institutional and Conceptual Framework for Jewish-Muslim Engagement

This paper calls for the establishment of a comprehensive academic and theological center to be created and located at a prestigious secular university in the United States. As the first of its kind in North America, it should be affiliated with both American Muslim and Jewish institutions. Modeled on similar Jewish-Christian centers, its mission will be to foster both a neutral ground for dialogue and the development of a theology of Jewish-Muslim coexistence

Digital video technology - today and tomorrow: 11th office information technology conference

Digital video is probably computing`s fastest moving technology today. Just three years ago, the zenith of digital video technology on the PC was the successful marriage of digital text and graphics with analog audio and video by means of expensive analog laser disc players and video overlay boards. The state of the art involves two different approaches to fully digital video on computers: hardware-assisted and software-only solutions

Fits & Starts: The Difficult Path for Working Single Parents

With dramatic shifts in the economy in recent years, it has become increasingly difficult for families to move into or stay in the middle class without access to higher education and skills training. Government-sponsored work supports help by providing direct assistance to working families to meet basic needs, such as child care, food, and housing. Yet, many supports do not reach low-wage working families in Massachusetts because of low eligibility thresholds, inadequate funding, limited availability, limited awareness, and numerous barriers to accessing such supports. Even for low-wage workers who do receive key work supports, such as subsidized child care and housing, reductions and elimination of these supports at low wages can impede vulnerable families’ progress toward the middle class. This report highlights the difficult choices Massachusetts low-wage workers must make between moving up the wage ladder and losing critical work supports before they are economically stable. It identifies specific points along the income ladder at which workers are faced with difficult trade-offs between higher earnings and career advancement on the one hand and the resulting loss of important supports on the other. Those receiving work supports find that their net monthly resources—their after-tax income from earnings plus the value of work supports, minus the cost of all basic needs—do not rise in step with wage increases for full-time workers earning between $11 and$29 per hour. Instead, these workers discover that at higher wage levels they can be left with fewer resources at the end of the month than they had at lower wages. This report also highlights opportunities for state programs to adjust eligibility criteria and for service providers to offer new kinds of guidance in order to more effectively support those who are trying to work their way into the middle class. Most importantly, this report calls for greater investments in work supports for low-wage earners seeking to combine work with education or skills development. Such education and training can provide crucial leverage to help families leap over some of the pitfalls on the path toward middle-class membership. In fact, wages are closely linked to educational attainment, with post-secondary education contributing to significantly higher earnings than those attained by high school graduates and non-completers. In 2005, having an associate’s degree added $8,154 to a Massachusetts high school graduate’s annual median income, while earning a bachelor’s degree added$18,346. In view of the critical role of education and training in facilitating workers’ access to family-supportive wages, we recommend transforming the current work support system to sustain work, school, and family

Group 14 Metallocene Catalysts for Carbonyl Hydroboration and Cyanosilylation

A series of six Group 14 metallocene compounds (M = Ge, Sn, Pb) were studied as catalysts for carbonyl hydroboration and cyanosilylation reactions at room temperature. Both bis(pentamethylcyclopentadienyl) and tetramethyldisiloxa[3]metallocenophane compounds were compared. The tin and lead metallocenophanes exhibited the highest reactivity in hydroboration and cyanosilylation reactions. Hammett analysis of aldehyde hydroboration provided a ρ value of 0.73, suggesting a buildup of negative charge during the turnover-limiting step, consistent with the transition state for hydride transfer to the carbonyl center. NMR studies of Lewis acidity indicate that the Ge, Sn, and Pb tetramethyldisiloxa[3]metallocenophane compounds are weak Lewis acids

Linear stability of planar premixed flames: reactive Navier-Stokes equations with finite activation energy and arbitrary Lewis number

A numerical shooting method for performing linear stability analyses of travelling waves is described and applied to the problem of freely propagating planar premixed flames. Previous linear stability analyses of premixed flames either employ high activation temperature asymptotics or have been performed numerically with finite activation temperature, but either for unit Lewis numbers (which ignores thermal-diffusive effects) or in the limit of small heat release (which ignores hydrodynamic effects). In this paper the full reactive Navier-Stokes equations are used with arbitrary values of the parameters (activation temperature, Lewis number, heat of reaction, Prandtl number), for which both thermal-diffusive and hydrodynamic effects on the instability, and their interactions, are taken into account. Comparisons are made with previous asymptotic and numerical results. For Lewis numbers very close to or above unity, for which hydrodynamic effects caused by thermal expansion are the dominant destablizing mechanism, it is shown that slowly varying flame analyses give qualitatively good but quantitatively poor predictions, and also that the stability is insensitive to the activation temperature. However, for Lewis numbers sufficiently below unity for which thermal-diffusive effects play a major role, the stability of the flame becomes very sensitive to the activation temperature. Indeed, unphysically high activation temperatures are required for the high activation temperature analysis to give quantitatively good predictions at such low Lewis numbers. It is also shown that state-insensitive viscosity has a small destabilizing effect on the cellular instability at low Lewis numbers

A Brain-Machine Interface for Control of Medically-Induced Coma

Medically-induced coma is a drug-induced state of profound brain inactivation and unconsciousness used to treat refractory intracranial hypertension and to manage treatment-resistant epilepsy. The state of coma is achieved by continually monitoring the patient's brain activity with an electroencephalogram (EEG) and manually titrating the anesthetic infusion rate to maintain a specified level of burst suppression, an EEG marker of profound brain inactivation in which bursts of electrical activity alternate with periods of quiescence or suppression. The medical coma is often required for several days. A more rational approach would be to implement a brain-machine interface (BMI) that monitors the EEG and adjusts the anesthetic infusion rate in real time to maintain the specified target level of burst suppression. We used a stochastic control framework to develop a BMI to control medically-induced coma in a rodent model. The BMI controlled an EEG-guided closed-loop infusion of the anesthetic propofol to maintain precisely specified dynamic target levels of burst suppression. We used as the control signal the burst suppression probability (BSP), the brain's instantaneous probability of being in the suppressed state. We characterized the EEG response to propofol using a two-dimensional linear compartment model and estimated the model parameters specific to each animal prior to initiating control. We derived a recursive Bayesian binary filter algorithm to compute the BSP from the EEG and controllers using a linear-quadratic-regulator and a model-predictive control strategy. Both controllers used the estimated BSP as feedback. The BMI accurately controlled burst suppression in individual rodents across dynamic target trajectories, and enabled prompt transitions between target levels while avoiding both undershoot and overshoot. The median performance error for the BMI was 3.6%, the median bias was -1.4% and the overall posterior probability of reliable control was 1 (95% Bayesian credibility interval of [0.87, 1.0]). A BMI can maintain reliable and accurate real-time control of medically-induced coma in a rodent model suggesting this strategy could be applied in patient care.National Institutes of Health (U.S.) (Director's Transformative Award R01 GM104948)National Institutes of Health (U.S.) (Pioneer Award DP1-OD003646)National Institutes of Health (U.S.) (NIH K08-GM094394)Massachusetts General Hospital. Dept. of Anesthesia and Critical Car