76 research outputs found
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Formulation Efforts for Direct Vitrification of INEEL Blend Calcine Waste Simulate: Fiscal Year 2000
This report documents the results of glass formulation efforts for Idaho National Engineering and Environmental Laboratory (INEEL) high level waste (HWL) calcine. Two waste compositions were used during testing. Testing started by using the Run 78 calcine composition and switched to simulated Blend calcine composition when it became available. The goal of the glass formulation efforts was to develop a frit composition that will accept higher waste loading that satisfies the glass processing and product acceptance constraints. 1. Melting temperature of 1125 ? 25?C 2. Viscosity between 2 and 10 Pa?s at the melting temperature 3. Liquidus temperature at least 100?C below the melting temperature 4. Normalized release of B, Li and Na each below 1 g/m2 (per ASTM C 1285-97) Glass formulation efforts tested several frit compositions with variable waste loadings of Run 78 calcine waste simulant. Frit 107 was selected as the primary candidate for processing since it met all process and performance criteria up to 45 mass% waste loading. When the simulated Blend calcine waste composition became available Frits 107 and 108 compositions were retested and again Frit 107 remained the primary candidate. However, both frits suffered a decrease in waste loading when switching from the Run 78 calcine to simulated Blend calcine waste composition. This was due to increase concentrations of both F and Al2O3 along with a decrease in CaO and Na2O in the simulate Blend calcine waste all of which have strong impacts on the glass properties that limit waste loading of this type of waste
Independent Review Support for Phoenix Mars Mission Robotic Arm Brush Motor Failure
The Phoenix Project requested the NASA Engineering and Safety Center (NESC) perform an independent peer review of the Robotic Arm (RA) Direct Current (DC) motor brush anomalies that originated during the Mars Exploration Rover (MER) Project and recurred during the Phoenix Project. The request was to evaluate the Phoenix Project investigation efforts and provide an independent risk assessment. This includes a recommendation for additional work and assessment of the flight worthiness of the RA DC motors. Based on the investigation and findings contained within this report, the IRT concurs with the risk assessment Failure Cause / Corrective Action (FC/CA) by the project, "Failure Effect Rating "3"; Major Degradation or Total Loss of Function, Failure Cause/Corrective Action Rating Currently "4"; Unknown Cause, Uncertainty in Corrective Action.
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CURRENT PROGRESS AND FUTURE PLANS FOR THE DOE OFFICE OF ENVIRONMENTAL MANAGEMENT INTERNATIONAL PROGRAM
The U.S. Department of Energy's (DOE) Office of Environmental Management (EM) has collaborated with various international institutes for many years on radioactive waste management challenges of mutual concern. Currently, DOE-EM is performing collaborative work with researchers at the Khlopin Radium Institute and the SIA Radon Institute in Russia and the Ukraine's International Radioecology Laboratory to explore issues related to high-level waste and to investigate experience and technologies that could support DOE-EM site cleanup needs. Specific initiatives include: (1) Application of the Cold Crucible Induction Heated Melter to DOE Wastes--SIA Radon and Savannah River National Laboratory; (2) Improved Solubility and Retention of Troublesome Components in SRS and Hanford Waste Glasses--Khlopin Radium Institute, Pacific Northwest National Laboratory and Savannah River National Laboratory; and (3) Long-term Impacts from Radiation/Contamination within the Chernobyl Exclusion Zone--International Radioecology Laboratory and Savannah River National Laboratory. This paper provides an overview of the status of the current International Program task activities. The paper will also provide insight into the future direction for the program. Specific ties to the current DOE-EM technology development multi-year planning effort will be highlighted as well as opportunities for future international collaborations
MicroRNA expression signature in human abdominal aortic aneurysms
Background: Abdominal aortic aneurysm (AAA) is a dilatation of the aorta affecting most frequently elderly men. Histologically AAAs are characterized by inflammation, vascular smooth muscle cell apoptosis, and extracellular matrix degradation. The mechanisms of AAA formation, progression, and rupture are currently poorly understood. A previous mRNA expression study revealed a large number of differentially expressed genes between AAA and non-aneurysmal control aortas. MicroRNAs (miRNAs), small non-coding RNAs that are post-transcriptional regulators of gene expression, could provide a mechanism for the differential expression of genes in AAA. Methods: To determine differences in miRNA levels between AAA (n = 5) and control (n = 5) infrarenal aortic tissues, a microarray study was carried out. Results were adjusted using Benjamini-Hochberg correction (adjusted p\u3c 0.05). Real-time quantitative RT-PCR (qRT-PCR) assays with an independent set of 36 AAA and seven control tissues were used for validation. Potential gene targets were retrieved from miRNA target prediction databases Pictar, TargetScan, and MiRTarget2. Networks from the target gene set were generated and examined using the network analysis programs, CytoScape® and Ingenuity Pathway Core Analysis®. Results: A microarray study identified eight miRNAs with significantly different expression levels between AAA and controls (adjusted p \u3c 0.05). Real-time qRT-PCR assays validated the findings for five of the eight miRNAs. A total of 222 predicted miRNA target genes known to be differentially expressed in AAA based on a prior mRNA microarray study were identified. Bioinformatic analyses revealed that several target genes are involved in apoptosis and activation of T cells. Conclusions: Our genome-wide approach revealed several differentially expressed miRNAs in human AAA tissue suggesting that miRNAs play a role in AAA pathogenesis. Keywords: Apoptosis, Microarray analysis, Vascular biology, miRNA-mRNA analysis, Network analysi
Why Reform Fails : The ‘Politics of Policies’ in Costa Rican Telecommunications Liberalization
As the \u27Washington Consensus\u27 reforms are losing momentum in Latin America, the Inter-
American Development Bank (IDB) is calling for shifting the focus from the content of policy
choices to the political process of their implementation. As this paper studies the paradigmatic
case of telecommunications reform in Costa Rica it underscores the importance
of these \u27politics of policies\u27. The analysis finds, however, that the failure of repeated liberalization
initiatives was not only due to policy-makers\u27 errors in steering the project
through \u27the messy world of politics\u27 (IDB); instead, as liberalization remained unpopular,
policy content indeed mattered, and only the interaction of both explains the outcome.
Particular attention is drawn to the political feed-back effects, as the failed reform, precisely
because it had been backed by bi-partisan support, became a catalyst for the disintegration
of the country\u27s long-standing two-party system.In dem Maße, in dem die mit dem „Washington Consensus“ verbundenen Reformen in Lateinamerika
ins Stocken geraten sind, plädiert die Inter-American Development Bank (IDB)
für eine stärkere Berücksichtigung nicht nur der Politikinhalte (policies), sondern auch des
politischen Prozesses von deren Umsetzung (politics). Die vorliegende Untersuchung zum
paradigmatischen Fall der Reform des Telekommunikationssektors in Costa Rica unterstreicht
die Bedeutung dieser „politics of policies“. Sie zeigt allerdings auch, dass Ursache
für das Scheiten wiederholter Liberalisierungsinitiativen nicht nur Fehler der Politiker sind,
das Vorhaben durch „die unordentliche Welt der politics“ (IDB) zu steuern. Die breite gesellschaftliche
Opposition gegen den Liberalisierungskurs bleibt. Nur die Interaktion von beiden,
politics und policies, erklärt Verlauf und Ergebnis der Reform. Besonderes Augenmerk
widmet die Studie den politischen Rückwirkungen der gescheiterten Reform: Sie wurde,
just weil sie von beiden etablierten Parteien unterstützt wurde, zum Katalysator für den Zerfall
des seit Jahrzehnten etablierten Zweiparteiensystems des Landes
Formulation and Characterization of Waste Glasses with Varying Processing Temperature
This report documents the preliminary results of glass formulation and characterization accomplished within the finished scope of the EM-31 technology development tasks for WP-4 and WP-5, including WP-4.1.2: Glass Formulation for Next Generation Melter, WP-5.1.2.3: Systematic Glass Studies, and WP-5.1.2.4: Glass Formulation for Specific Wastes. This report also presents the suggested studies for eventual restart of these tasks. The initial glass formulation efforts for the cold crucible induction melter (CCIM), operating at {approx}1200 C, with selected HLW (AZ-101) and LAW (AN-105) successfully developed glasses with significant increase of waste loading compared to that is likely to be achieved based on expected reference WTP formulations. Three glasses formulated for AZ-101HLW and one glass for AN-105 LAW were selected for the initial CCIM demonstration melter tests. Melter tests were not performed within the finished scope of the WP-4.1.2 task. Glass formulations for CCIM were expanded to cover additional HLWs that have high potential to successfully demonstrate the unique advantages of the CCIM technologies based on projected composition of Hanford wastes. However, only the preliminary scoping tests were completed with selected wastes within the finished scope. Advanced glass formulations for the reference WTP melter, operating at {approx}1200 C, were initiated with selected specific wastes to determine the estimated maximum waste loading. The incomplete results from these initial formulation efforts are summarized. For systematic glass studies, a test matrix of 32 high-aluminum glasses was completed based on a new method developed in this study
Glass Formulation Development for INEEL Sodium-Bearing Waste
Studies were performed to develop and test a glass formulation for immobilization of sodium-bearing waste (SBW). SBW is a high soda, acid high activity waste stored at the INEEL in 10 underground tanks. It was determined in previous studies that SBW?s sulfur content dictates the its loading in borosilicate glasses to be melted by currently assumed processes. If the sulfur content (which is ~4.5 mass% SO3 on a non-volatile oxide basis in SBW) of the melter feed is too high then a molten alkali sulfate containing salt phase accumulates on the melt surface. The avoidance of salt accumulation during the melter process and the maximization of sulfur incorporation into the glass melt were the main focus of this development work. A glass was developed for 20 mass% SBW (on a non-volatile oxide basis), which contained 0.91 mass% SO3, that met all the processing and product quality constraint determined for SBW vitrification at a planned INEEL treatment plant?SBW-22-20. This report summarizes the formulation efforts and presents the data developed on a series of glasses with simulated SBW. Summar
Bolivia and the paradoxes of democratic consolidation
In Bolivia from the 1990s on, two presidents were ousted by popular protests, and protests were rampant. The protests expressed a growing discontent not only with successive administrations and their policies but with politics itself. The polity failed to built trust in democracy, ignored or repressed protests, and thus contributed to a process of democratic "deconsolidation." The main factors were corruption and the reluctance of the traditional political parties to discuss the neoliberal economic model. As a result, the current administration of Evo Morales faces two challenges: to change economic policies and to repair the support for democracy
Reduced fire severity offers near-term buffer to climate-driven declines in conifer resilience across the western United States
Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, the relative importance of and interactions between these drivers of forest change remain unresolved, particularly over upcoming decades. Here, we assess how the interactive impacts of changing climate and wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset of postfire conifer regeneration from 10,230 field plots. Our findings highlight declining regeneration capacity across the West over the past four decades for the eight dominant conifer species studied. Postfire regeneration is sensitive to high-severity fire, which limits seed availability, and postfire climate, which influences seedling establishment. In the near-term, projected differences in recruitment probability between low- and high-severity fire scenarios were larger than projected climate change impacts for most species, suggesting that reductions in fire severity, and resultant impacts on seed availability, could partially offset expected climate-driven declines in postfire regeneration. Across 40 to 42% of the study area, we project postfire conifer regeneration to be likely following low-severity but not high-severity fire under future climate scenarios (2031 to 2050). However, increasingly warm, dry climate conditions are projected to eventually outweigh the influence of fire severity and seed availability. The percent of the study area considered unlikely to experience conifer regeneration, regardless of fire severity, increased from 5% in 1981 to 2000 to 26 to 31% by mid-century, highlighting a limited time window over which management actions that reduce fire severity may effectively support postfire conifer regeneration. © 2023 the Author(s)
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