40 research outputs found
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PERSPECTIVES ON A DOE CONSEQUENCE INPUTS FOR ACCIDENT ANALYSIS APPLICATIONS
Department of Energy (DOE) accident analysis for establishing the required control sets for nuclear facility safety applies a series of simplifying, reasonably conservative assumptions regarding inputs and methodologies for quantifying dose consequences. Most of the analytical practices are conservative, have a technical basis, and are based on regulatory precedent. However, others are judgmental and based on older understanding of phenomenology. The latter type of practices can be found in modeling hypothetical releases into the atmosphere and the subsequent exposure. Often the judgments applied are not based on current technical understanding but on work that has been superseded. The objective of this paper is to review the technical basis for the major inputs and assumptions in the quantification of consequence estimates supporting DOE accident analysis, and to identify those that could be reassessed in light of current understanding of atmospheric dispersion and radiological exposure. Inputs and assumptions of interest include: Meteorological data basis; Breathing rate; and Inhalation dose conversion factor. A simple dose calculation is provided to show the relative difference achieved by improving the technical bases
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SIMPLE TRANSIENT CALCULATIONS OF CELL FLAMMABLE GAS CONCENTRATIONS
The Saltstone Facility at Savannah River Site (SRS) mixes low-level radiological liquid waste with grout for permanent disposal as cement in vault cells. The grout mixture is poured into each cell in approximately 17 batches (8 to 10 hours duration). The grout mixture contains ten flammable gases of concern that are released from the mixture into the cell. Prior to operations, simple parametric transient calculations were performed to develop batch parameters (including schedule of batch pours) to support operational efficiency while ensuring that a flammable gas mixture does not develop in the cell vapor space. The analysis demonstrated that a nonflammable vapor space environment can be achieved, with workable operational constraints, without crediting the ventilation flow as a safety system control. Isopar L was identified as the primary flammable gas of concern. The transient calculations balanced inflows of the flammable gases into the vapor space with credited outflows of diurnal breathing through vent holes and displacement from new grout pours and gases generated. Other important features of the analyses included identifying conditions that inhibited a well-mixed vapor space, the expected frequency and duration of such conditions, and the estimated level of stratification that could develop
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
Recruitment and retention of women in a large randomized control trial to reduce repeat preterm births: the Philadelphia Collaborative Preterm Prevention Project
<p>Abstract</p> <p>Background</p> <p>Recruitment and retention of patients for randomized control trial (RCT) studies can provide formidable challenges, particularly with minority and underserved populations. Data are reported for the Philadelphia Collaborative Preterm Prevention Project (PCPPP), a large RCT targeting risk factors for repeat preterm births among women who previously delivered premature (< 35 weeks gestation) infants.</p> <p>Methods</p> <p>Design of the PCPPP incorporated strategies to maximize recruitment and retention. These included an advanced database system tracking follow-up status and assessment completion rates; cultural sensitivity training for staff; communication to the community and eligible women of the benefits of participation; financial incentives; assistance with transportation and supervised childcare services; and reminder calls for convenient, flexibly scheduled appointments. Analyses reported here: 1) compare recruitment projections to actual enrollment 2) explore recruitment bias; 3) validate the randomization process 4) document the extent to which contact was maintained and complete assessments achieved 5) determine if follow-up was conditioned upon socio-economic status, race/ethnicity, or other factors.</p> <p>Results</p> <p>Of eligible women approached, 1,126 (77.7%) agreed to participate fully. Of the 324 not agreeing, 118 (36.4%) completed a short survey. Consenting women were disproportionately from minority and low SES backgrounds: 71.5% consenting were African American, versus 38.8% not consenting. Consenting women were also more likely to report homelessness during their lifetime (14.6% vs. 0.87%) and to be unmarried at the time of delivery (81.6% versus 47.9%). First one-month postpartum assessment was completed for 83.5% (n = 472) of the intervention group (n = 565) and 76% (426) of the control group. Higher assessment completion rates were observed for the intervention group throughout the follow-up. Second, third, fourth and fifth postpartum assessments were 67.6% vs. 57.5%, 60.0% vs. 48.9%, 54.2% vs. 46.3% and 47.3% vs. 40.8%, for the intervention and control group women, respectively. There were no differences in follow-up rates according to race/ethnicity, SES or other factors. Greater retention of the intervention group may reflect the highly-valued nature of the medical and behavior services constituting the intervention arms of the Project.</p> <p>Conclusion</p> <p>Findings challenge beliefs that low income and minority women are averse to enrolling and continuing in clinical trials or community studies.</p
This work was supported by The Department of the Interior Alaska Climate Adaptation Science Center, which is managed by the USGS National Climate Adaptation Science Center.
53 pages : color illustrations, color maps ; 28 cmThis report is designed as a living document to inform the community, decision makers, and academics and to serve as a learning and teaching tool. The nine key messages summarized on pages 6 and 7 are intended for use as a quick reference. Unique for this type of report, these key messages highlight actions by Juneau's civil society, including local nonprofit organizations.We thank the City and Borough of Juneau (CBJ) for its support in bringing this vital information on climate change
to the Juneau community and to others. Thanks especially to all the co-authors and other contributors. The
inclusion of such a diverse array of material, including local knowledge, was made possible by the many elders,
scientists, and local experts who contributed their time and expertise. The report is online at acrc.alaska.edu/
juneau-climate-report. It is an honor to be the lead editor and project manager for this critical effort. We have a
chance to save our world from the most extreme effects of climate change. Let us take it.
Gunalchéesh, sincerely,
James E. Powell (Jim), PhD, Alaska Coastal Rainforest Center, UASWelcome / Thomas F. Thornton -- Juneau's climate report: History and background / Bruce Botelho -- Using this report -- Acknowledgements / James E. Powell -- A regional Indigenous perspective on adaptation: The Central Council of Tlingit & Haida Indian Tribes of Alaska's Climate Change Adaptation Plan / Raymond Paddock -- Nine key messages -- What we're experiencing: Atmospheric, marine, terrestrial, and ecological effects. Climate. Setting and seasons / Tom Ainsworth -- More precipitation / Rick Thoman -- Higher temperatures / Rich Thoman -- Less snowfall / Eran Hood -- Ocean. Surface uplift and sea level rise / Eran Hood -- Extensive effects of a warming ocean / Heidi Pearson -- Increasing ocean acidification / Robert Foy -- Land. More landslides / Sonia Nagorski & Aaron Jacobs -- Mendenhall Glacier continues to retreat / Jason Amundson -- Tongass Forest impacts and carbon / Dave D'Amore -- Animals. Terrestrial vertebrates in A¿¿ak'w & T'aak¿łu Aani¿¿ / Richard Carstensen -- Three animals as indicators of change / Richard Carstensen -- Insects / Bob Armstrong -- What we're doing: Community response. Upgrading ifrastructure and mitigation / Katie Koester -- Upgrading utilities and other energy consumers / Alec Mesdag -- Growing demand for hydropower / Duff Mitchell -- Leading a shift in transportation / Duff Mitchell -- Maintaining mental health through community and recreation / Linda Kruger & Kevin Maier -- Food security / Darren Snyder & Jim Powell -- Large cruise ship air emissions / Jim Powell -- Tourists' views on climate change mitigation / Jim Powell -- Lowering greenhouse gas emissions / Jim Powell & Peggy Wilcox -- Residents taking action / Andy Romanoff & Jim Powell -- Summary and Recommendations -- References -- Graphics and data sources -- Appendix: Juneau nonprofit climate change organization
Where and With Whom Does a Brief Social-Belonging Intervention Promote Progress in College?
A promising way to mitigate inequality is by addressing students’ worries about belonging. But where and with whom is this social-belonging intervention effective? Here we report a team-science randomized controlled experiment with 26,911 students at 22 diverse institutions. Results showed that the social-belonging intervention, administered online before college (in under 30 minutes), increased the rate at which students completed the first year as full-time students, especially among students in groups that had historically progressed at lower rates. The college context also mattered: The intervention was effective only when students’ groups were afforded opportunities to belong. This study develops methods for understanding how student identities and contexts interact with interventions. It also shows that a low-cost, scalable intervention generalizes its effects to 749 4-year institutions in the United States