Is Environmental Justice Good for White Folks?

This paper examines spatial variations in exposure to toxic air pollution from industrial facilities in urban areas of the United States, using geographic microdata from the U.S. Environmental Protection Agency’s Risk-Screening Environmental Indicators project. We find that average exposure in an urban area is positively correlated with the extent of racial and ethnic disparity in the distribution of the exposure burden. This correlation could arise from causal linkages in either or both directions: the ability to displace pollution onto minorities may lower the effective cost of pollution for industrial firms; and higher average pollution burdens may induce whites to invest more political capital in efforts to influence firms’ siting decisions. Furthermore, we find that in urban areas with higher minority pollution-exposure discrepancies, average exposures tend to be higher for all population subgroups, including whites. In other words, improvements in environmental justice in the United States could benefit not only minorities but also whites.environmental justice; air pollution; industrial toxics; Risk-Screening Environmental Indicators.

Green Recovery: A Program to Create Good Jobs & Start Building a Low-Carbon Economy

September 2008As the nation debates its energy future, this report shows that the U.S. can create two million jobs by investing in a rapid green economic recovery program, which will strengthen the economy, increase energy independence, and fight global warming.Green Recovery – A Program to Create Good Jobs and Start Building a Low-Carbon Economy was prepared by PERI under commission by the Center for American Progress and released by a coalition of labor and environmental groups. Focusing on a short-term clean energy and jobs program, Green Recovery reports that a short-term green stimulus package would create two million jobs nationwide over two years. >> Read more about Green Recovery and download the full report

The Influence of GI and GII on the Compression After Impact Strength of Carbon Fiber/Epoxy Laminates and Sandwich Structure

This study measured the compression after impact strength of IM7 carbon fiber laminates made from epoxy resins with various mode I and mode II toughness values to observe the effects of these toughness values on the resistance to damage formation and subsequent residual compression strength-carrying capabilities. Both monolithic laminates and sandwich structure were evaluated. A total of seven different epoxy resin systems were used ranging in approximate GI values of 245-665 J/sq m and approximate GII values of 840-2275 J/sq m. The results for resistance to impact damage formation showed that there was a direct correlation between GII and the planar size of damage, as measured by thermography. Subsequent residual compression strength testing suggested that GI had no influence on the measured values and most of the difference in compression strength was directly related to the size of damage. Thus, delamination growth assumed as an opening type of failure mechanism does not appear to be responsible for loss of compression strength in the specimens examined in this study

Three Essays on Racial Disparities in Infant Health and Air Pollution Exposure

This three-essay dissertation examines racial disparities in infant health outcomes and exposure to air pollution in Texas. It also asks whether the EPA\u27s Risk-Screening Environmental Indicators Geographic Microdata (RSEI-GM) might be used to assess the effects of little-studied toxic air pollutants on infant health outcomes. Chapter 1 contributes to the ``weathering\u27\u27 literature, which has shown that disparities in infant health outcomes between non-Hispanic black and non-Hispanic white women tend to widen with age. In this study, we ask whether the same patterns are observed in Texas and among Hispanic women, since other studies have focused on black and white women from other regions. We find that black and Hispanic women in Texas do ``weather\u27\u27 earlier than white mothers with respect to rates of low birthweight and preterm birth. This differential weathering appears to be mediated by racial disparities in the distribution and response to socioeconomic risk factors, though a large gap between black and white mothers across all ages remains unexplained. Chapter 2 extends the statistical environmental justice literature by examining the distribution of toxic air pollution across infants in Texas. We find that, within Texas cities, being black or Hispanic is a significant predictor of how much pollution one is exposed to at birth. We further find that, among mothers who move between births, white mothers tend to move to significantly cleaner areas than black or Hispanic mothers. In Chapter 3, we use geocoded birth records matched to square-kilometer pollution concentration estimates from the RSEI-GM to ask whether the pollution-outcome relationships that emerge through regression analysis are similar to the effects found in previous research. If so, the RSEI-GM might be used to study the health effects of nearly 600 chemicals tracked in that dataset. We conclude, based on instability of results across various specifications and lack of correspondence to previous results, that the merged birth record-RSEI data are not appropriate for statistical epidemiology research

Optimization of NTP System Truss to Reduce Radiation Shield Mass

The benefits of nuclear thermal propulsion are numerous and relevant to the current NASA mission goals involving but not limited to the crewed missions to mars and the moon. They do however also present new and unique challenges to the design and logistics of launching/operating spacecraft. One of these challenges, relevant to this discussion, is the significant mass of the shielding which is required to ensure an acceptable radiation environment for the spacecraft and crew. Efforts to reduce shielding mass are difficult to accomplish from material and geometric design points of the shield itself, however by increasing the distance between the nuclear engines and the main body of the spacecraft the required mass of the shielding is lessened considerably. The mass can be reduced significantly per unit length, though any additional mass added by the structure to create this distance serves to offset those savings, thus the design of a lightweight structure is ideal. The challenges of designing the truss are bounded by several limiting factors including; the loading conditions, the capabilities of the launch vehicle, and achieving the ideal truss length when factoring for the overall mass reduced. Determining the overall set of mass values for a truss of varying length is difficult since to maintain an optimally designed truss the geometry of the truss or its members must change. Thus the relation between truss mass and length for these loading scenarios is not linear, and instead has relation determined by the truss design. In order to establish a mass versus length trend for various truss designs to compare with the mass saved from the shield versus length, optimization software was used to find optimal geometric properties that still met the design requirements at established lengths. By solving for optimal designs at various lengths, mass trends could be determined. The initial design findings show a clear benefit to extending the engines as far from the main structure of the spacecraft as the launch vehicle's payload volume would allow when comparing mass savings verse the additional structure

Shielding Development for Nuclear Thermal Propulsion

Radiation shielding analysis and development for the Nuclear Cryogenic Propulsion Stage (NCPS) effort is currently in progress and preliminary results have enabled consideration for critical interfaces in the reactor and propulsion stage systems. Early analyses have highlighted a number of engineering constraints, challenges, and possible mitigating solutions. Performance constraints include permissible crew dose rates (shared with expected cosmic ray dose), radiation heating flux into cryogenic propellant, and material radiation damage in critical components. Design strategies in staging can serve to reduce radiation scatter and enhance the effectiveness of inherent shielding within the spacecraft while minimizing the required mass of shielding in the reactor system. Within the reactor system, shield design is further constrained by the need for active cooling with minimal radiation streaming through flow channels. Material selection and thermal design must maximize the reliability of the shield to survive the extreme environment through a long duration mission with multiple engine restarts. A discussion of these challenges and relevant design strategies are provided for the mitigation of radiation in nuclear thermal propulsion

Utilizing Structured Light Scanning Technology for the Development of Structural Dynamic Analysis Models of Liquid Engine Hardware

No abstract availabl

Low-Temperature Behaviour of Charge Transfer Excitons in Narrow-Bandgap Polymer-Based Bulk Heterojunctions

Photoluminescence studies of the charge transfer exciton emission from a narrow-bandgap polymer-based bulk heterojunction are reported. The quantum yield of this emission is as high as 0.03%. Low temperature measurements reveal that while the dynamics of the singlet exciton is slower at low temperature, the dynamics of the charge transfer exciton emission is temperature independent. This behavior rules out any diffusion process of the charge transfer excitons and energy transfer from these interfacial states toward lower lying states. Photoluminescence measurements performed on the device under bias show a reduction (but not the total suppression) of the charge transfer exciton recombination. Finally, based on the low temperature results the role of the charge transfer excitons and the possible pathways to populate them are identified