The structure of human Nocturnin reveals a conserved ribonuclease domain that represses target transcript translation and abundance in cells
Abstract not provided
T. Abshire, Elizabeth↗
SEARCH · Engineering Papers
Results for “key activities”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Instantiation of the Damara Tern Platform for Advanced Materials and Manufacturing Technologies (AMMT) Program Collaborative Data Management
This work package focused on deploying an instance of the Damara Tern platform to support AMMT collaborative research activities. The objectives were to provide selected AMMT collaborators with access to a shared environment for capturing operations, trackables, and associated metadata, and to implement data entry functionalities that reflect site-specific procedures. Key activities included creating configurable, schema-driven entry forms and validating the data collection process. The report details the deployment process, the platform infrastructure, and the implemented data entry workflows, providing a reference for end users and establishing a foundation for future production-scale deployments.
36 MATERIALS SCIENCE↗
Molecular doping for control of gate bias stress in organic thin film transistors
The key active devices of future organic electronic circuits are organic thin film transistors (OTFTs). Reliability of OTFTs remains one of the most challenging obstacles to be overcome for broad commercial applications. In particular, bias stress was identified as the key instability under operation for numerous OTFT devices and interfaces. Despite a multitude of experimental observations, a comprehensive mechanism describing this behavior is still missing. Furthermore, controlled methods to overcome these instabilities are so far lacking. Here, we present the approach to control and significantly alleviate the bias stress effect by using molecular doping at low concentrations. For pentacene and silicon oxide as gate oxide, we are able to reduce the time constant of degradation by three orders of magnitude. The effect of molecular doping on the bias stress behavior is explained in terms of the shift of Fermi Level and, thus, exponentially reduced proton generation at the pentacene/oxide interface.
36 MATERIALS SCIENCE↗
Support for Advanced Fuel Fabrication MC&A Approaches
This report summarizes the key activities of the Material Protection, Accounting, and Control Technologies (MPACT) program’s safeguards training work package for FY25. The work focused on two main areas: domestic safeguards training and the development of new technologies for nuclear material accounting and control (NMAC). A key development during this FY was the delivery of NMAC statistics for US Nuclear Regulatory Commission requirements refresher course. The course objective was to assist industry in meeting the MC&A program requirements for fuel cycle facilities; this training focused on front-end bulk fuel cycle processes. At the same time, a report was prepared on the research output of an effort that focused on the benefits of commercial fuel debundling for NMAC and waste management. The MPACT team evaluated various technologies and proposed a fuel debundling detector that integrates gamma spectroscopy and neutron detection as the most practical solution. The scope of activities under this work package for FY26 focuses on developing a fundamental nuclear material control plan, also known as MC&A plan, for tristructural isotropic (TRISO) fuel fabrication facilities. This plan will address the various NMAC requirements for facilities that handle Category II.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Assessing potential targets of calcium action in light-modulated gravitropism
Light, through the mediation of the pigment phytochrome, modulates the gravitropic response of the shoots and roots of many plants. The transduction of both light and gravity stimuli appears to involve Ca(2+)-regulated steps, one or more of which may represent points of intersection between the two transduction chains. To be confident that Ca2+ plays a critical role in stimulus-response coupling for gravitropism, it will be important to identify specific targets of Ca2+ action whose function can be clearly linked to the regulation of growth. Calcium typically exerts its influence on cell metabolism through binding to and activating key regulatory proteins. The three best characterized of these proteins in plants are the calmodulins, calcium-dependent protein kinases, and annexins. In this review we summarize what is known about the structure and function of these proteins and speculate on how their activation by Ca2+ could influence the differential growth response of gravitropism.
Review, Tutorial↗
Alternate Retrieval A-105 Application Assessment Report
This report summarizes the historical development of the Confined Sluicing End Effector (CSEE) technology as well scarification technology. We also summarize the systems integration and deployment of that technology in the Gunite and Associated Tanks (GAAT) at the Oak Ridge Reservation where the retrieval system successfully removed the remaining sludge and heel in the eight tanks for tank closure and disposition. We also summarize the lessons learned from the deployment at Oak Ridge. Simulant development and testing have been key activities for any waste retrieval effort as many of the physical properties of the waste are unknown; therefore, this report discusses a bounding series of simulants that helps to reduce uncertainty for operations. These simulants have been developed for potential Hanford waste retrieval deployment. The potential key attributes for retrieval, based upon information provided by Washington River Protection Services (WRPS), of single-shell tank A-105 are discussed along with the potential application of CSEE technology to the challenges presented by the unique nature of A-105. These unique features include a major tear in the bottom of the tank, which necessitates technologies other than past practice sluicing to be deployed to prevent further intrusion of waste into the vadose zone. In addition, significant in-tank hardware makes A-105 particular challenging. However, there appear to be a number of parameters that should be investigated through additional testing or review of prior testing that may demonstrate the applicability of the CSEE technology to A-105. Testing of the Waste Retrieval End Effector (WREE), which was based on the original CSEE design, to demonstrate the ability to remove sludge and hardpan from Tank 241-C-106 will be reviewed to determine relevance to the Tank A-105 retrieval. There may be new requirements for the deployment system that accesses the tank with the CSEE because the tank bottom may not be flat, requiring the ability to maneuver the CSEE to maintain the appropriate stand-off distance from the CSEE and the tank bottom. Finally, we provide a set of recommendations, a set of task descriptions, and a range of estimated costs for a demonstration of the technology by the end of FY17. These tasks are summarized as: Complete system-level functional requirements; Procure or access the capacity to perform; Generate simulant development and simulant testing; Develop CSEE functionality; Develop demonstration plan; Perform demonstration; Analyze and document testing results; Perform project management and engineering.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Data Quality Objectives for Direct LAW Feed Acceptance and Qualification - 17122
The Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste (LAW) Facility has been designed to operate under two scenarios. In the primary operating scenario, the Pretreatment Facility configuration, waste is first processed through the WTP Pretreatment Facility. Then the low-activity liquid is transferred to the WTP LAW Facility for vitrification. Alternately, under a direct feed operating scenario, known as Direct Feed LAW (DFLAW), the supernatant portion of the tank waste, referred to as the LAW feed, is treated in a Low-Activity Waste Pretreatment System (LAWPS) prior to transfer of treated feed to LAW Facility. The DFLAW scenario is a strategy to begin treating Hanford tank wastes as soon as 2022. A program has been established as part of One System to integrate and align the waste feed acceptance and qualification requirements for processing in the LAWPS and the LAW facility. One key activity of the program is the development of integrated data quality objectives (DQO) using U.S. Environmental Protection Agency guidance for the DQO process. [1] The integrated approach focused on one sampling event that will provide sufficient and necessary data to meet both LAWPS and LAW Facility criteria. Existing data and historical information were taken into account to develop sampling and data collection requirements necessary to meet waste acceptance criteria and processing requirements for both LAWPS and LAW Facility. Using a conceptual model for the sampling and decision process, the seven steps of the DQO process were completed. This paper discusses the details of the integrated DQO process. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
A Conserved Surface Loop in Type I Dehydroquinate Dehydratases Positions an Active Site Arginine and Functions in Substrate Binding
Dehydroquinate dehydratase (DHQD) catalyzes the third step in the biosynthetic shikimate pathway. We present three crystal structures of the Salmonella enterica type I DHQD that address the functionality of a surface loop that is observed to close over the active site following substrate binding. Two wild-type structures with differing loop conformations and kinetic and structural studies of a mutant provide evidence of both direct and indirect mechanisms of involvement of the loop in substrate binding. In addition to allowing amino acid side chains to establish a direct interaction with the substrate, closure of the loop necessitates a conformational change of a key active site arginine, which in turn positions the substrate productively. The absence of DHQD in humans and its essentiality in many pathogenic bacteria make the enzyme a target for the development of nontoxic antimicrobials. The structures and ligand binding insights presented here may inform the design of novel type I DHQD inhibiting molecules.
59 BASIC BIOLOGICAL SCIENCES↗
Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation
WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m –2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Microgravity crystallization of perdeuterated tryptophan synthase for neutron diffraction
Abstract Biologically active vitamin B 6 -derivative pyridoxal 5′-phosphate (PLP) is an essential cofactor in amino acid metabolic pathways. PLP-dependent enzymes catalyze a multitude of chemical reactions but, how reaction diversity of PLP-dependent enzymes is achieved is still not well understood. Such comprehension requires atomic-level structural studies of PLP-dependent enzymes. Neutron diffraction affords the ability to directly observe hydrogen positions and therefore assign protonation states to the PLP cofactor and key active site residues. The low fluxes of neutron beamlines require large crystals (≥0.5 mm 3 ). Tryptophan synthase (TS), a Fold Type II PLP-dependent enzyme, crystallizes in unit gravity with inclusions and high mosaicity, resulting in poor diffraction. Microgravity offers the opportunity to grow large, well-ordered crystals by reducing gravity-driven convection currents that impede crystal growth. We developed the Toledo Crystallization Box (TCB), a membrane-barrier capillary-dialysis device, to grow neutron diffraction-quality crystals of perdeuterated TS in microgravity. Here, we present the design of the TCB and its implementation on Center for Advancement of Science in Space (CASIS) supported International Space Station (ISS) Missions Protein Crystal Growth (PCG)-8 and PCG-15. The TCB demonstrated the ability to improve X-ray diffraction and mosaicity on PCG-8. In comparison to ground control crystals of the same size, microgravity-grown crystals from PCG-15 produced higher quality neutron diffraction data. Neutron diffraction data to a resolution of 2.1 Å has been collected using microgravity-grown perdeuterated TS crystals from PCG-15.
59 BASIC BIOLOGICAL SCIENCES↗
Integrated Disposal Facility FY 2012 Glass Testing Summary Report
PNNL is conducting work to provide the technical basis for estimating radionuclide release from the engineered portion of the disposal facility for Hanford immobilized low-activity waste (ILAW). Before the ILAW can be disposed, DOE must conduct a performance assessment (PA) for the Integrated Disposal Facility (IDF) that describes the long-term impacts of the disposal facility on public health and environmental resources. As part of the ILAW glass testing program, PNNL is implementing a strategy, consisting of experimentation and modeling, to provide the technical basis for estimating radionuclide release from the glass waste form in support of future IDF PAs. Key activities in FY12 include upgrading the STOMP/eSTOMP codes to do near-field modeling, geochemical modeling of PCT tests to determine the reaction network to be used in the STOMP codes, conducting PUF tests on selected glasses to simulate and accelerate glass weathering, developing a Monte Carlo simulation tool to predict the characteristics of the weathered glass reaction layer as a function of glass composition, and characterizing glasses and soil samples exhumed from an 8-year lysimeter test. The purpose of this report is to summarize the progress made in fiscal year (FY) 2012 and the first quarter of FY 2013 toward implementing the strategy with the goal of developing an understanding of the long-term corrosion behavior of LAW glasses.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Analysis of Transient Pressure and Rate Data in a Complex of Enhanced Oil Recovery Fields in Northern Michigan
The Midwest Regional Carbon Sequestration Partnership (MRCSP) was founded in 2003 as part of the U.S. Department of Energy’s (DOE’s) Regional Carbon Sequestration Partnership initiative. Since its founding, MRCSP has made significant strides toward making CCUS a viable option for states in the region. The public/private consortium, funded through the DOE Regional Carbon Sequestration Initiative, brings together nearly 40 industry partners and 10 states. Battelle, as the project lead, oversees research, development and operations and coordinates activities among the partners. The incremental, phased approach has built a valuable knowledge base for the industry and paved the way for commercial-scale adoption of CCUS technologies. From 2008 to 2020, MRCSP Phase III focused on the development of large-scale injection projects. This report is part of a series of reports prepared under the Midwestern Regional Carbon Sequestration Partnership (MRCSP) Phase III (Development Phase). These reports summarize and detail the findings of the work conducted under the Phase III project. A key activity of the MRCSP monitoring program was to continuously monitor the CO 2 injection and bottom-hole reservoir pressure in the injection wells and selected monitoring wells in the study reefs from 2013 through 2019. During the monitoring period, which varied from reef to reef, the reefs were undergoing one or more phases of development, such as CO 2 injection without hydrocarbon production, CO 2 injection with production Enhanced Oil Recovery (EOR), production without CO 2 injection, and idle (no injection or production) in pressure depleted condition. A multi-year record of reservoir pressure and injection rate data are available for one or more wells for each reef for analysis. This report discusses the methodology and results of various types of analyses performed with this data, with the primary objective of characterizing the in-situ permeability of the formation of interest.
01 COAL, LIGNITE, AND PEAT↗
Dynamic Copper Site Redispersion through Atom Trapping in Zeolite Defects
Single-site copper-based catalysts have shown remarkable activity and selectivity for a variety of reactions. However, deactivation by sintering in high-temperature reducing environments remains a challenge and often limits their use due to irreversible structural changes to the catalyst. Here, we report zeolite-based copper catalysts in which copper oxide agglomerates formed after reaction can be repeatedly redispersed back to single sites using an oxidative treatment in air at 550 °C. Under different environments, single-site copper in Cu–Zn–Y/deAlBeta undergoes dynamic changes in structure and oxidation state that can be tuned to promote the formation of key active sites while minimizing deactivation through Cu sintering. For example, single-site Cu 2+ reduces to Cu 1+ after catalyst pretreatment (270 °C, 101 kPa H 2 ) and further to Cu0 nanoparticles under reaction conditions (270–350 °C, 7 kPa EtOH, 94 kPa H 2 ) or accelerated aging (400–450 °C, 101 kPa H 2 ). After regeneration at 550 °C in air, agglomerated CuO was dispersed back to single sites in the presence and absence of Zn and Y, which was verified by imaging, in situ spectroscopy, and catalytic rate measurements. Ab initio molecular dynamics simulations show that solvation of CuO monomers by water facilitates their transport through the zeolite pore, and condensation of the CuO monomer with a fully protonated silanol nest entraps copper and reforms the single-site structure. Importantly, the capability of silanol nests to trap and stabilize copper single sites under oxidizing conditions could extend the use of single-site copper catalysts to a wider variety of reactions and allows for a simple regeneration strategy for copper single-site catalysts.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
LONG-TERM STEWARDSHIP AT DOE HANFORD SITE - 12575
The U.S. Department of Energy's (DOE) Hanford Site is located in southeast Washington and consists of 1,518 square kilometers (586 square miles) of land. Established in 1943 as part of the Manhattan Project, Hanford workers produced plutonium for our nation's nuclear defense program until the mid 1980's. Since then, the site has been in cleanup mode that is being accomplished in phases. As we achieve remedial objectives and complete active cleanup, DOE will manage Hanford land under the Long-Term Stewardship (LTS) Program until completion of cleanup and the site becomes ready for transfer to the post cleanup landlord - currently planned for DOE's Office of Legacy Management (LM). We define Hanford's LTS Program in the ''Hanford Long-Term Stewardship Program Plan,'' (DOE/RL-201 0-35)[1], which describes the scope including the relationship between the cleanup projects and the LTS Program. DOE designed the LTS Program to manage and provide surveillance and maintenance (S&M) of institutional controls and associated monitoring of closed waste sites to ensure the protection of human health and the environment. DOE's Richland Operations Office (DOE-RL) and Hanford cleanup and operations contractors collaboratively developed this program over several years. The program's scope also includes 15 key activities that are identified in the DOE Program Plan (DOE/RL-2010-35). The LTS Program will transition 14 land segments through 2016. The combined land mass is approximately 570 square kilometers (220 square miles), with over 1,300 active and inactive waste sites and 3,363 wells. Land segments vary from buffer zone property with no known contamination to cocooned reactor buildings, demolished support facilities, and remediated cribs and trenches. DOE-RL will transition land management responsibilities from cleanup contractors to the Mission Support Contract (MSC), who will then administer the LTS Program for DOE-RL. This process requires an environment of cooperation between the contractors and DOE-RL. Information Management (IM) is a key part of the LTS program. The IM Program identifies, locates, stores, protects and makes accessible Hanford LTS records and data to support the transfer of property ultimately to LM. As such, DOE-RL manages the Hanford LTS Program in a manner consistent with LM's goals, policies, and procedures.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Collaborative Research Programme in Decommissioning, Immobilisation and Storage Solutions for Nuclear Waste Inventories (DISTINCTIVE) - 16466
The UK government remains committed to nuclear power as an important part of the energy generation capacity over the next 30-50 years and possibly beyond, with aspirations for both new-build power stations and lifetime extension of the existing fleet. A central component of public acceptance for any new-build programme is the need to demonstrate our ability to safely manage and dispose of high- and intermediate-level wastes from legacy nuclear operations. Clear milestones associated with the needs of waste management and decommissioning have been provided by the UK government, and most rely on further research and technical developments being delivered over the next 10-20 years. The DISTINCTIVE (Decommissioning, Immobilisation and Storage Solutions for Nuclear Waste Inventories) consortium is carrying out research that addresses the broad area of nuclear waste and decommissioning, bringing together key industry partners and leading academic researchers from 10 of the UK's leading research intensive universities. The research being carried out is multi-disciplinary and covers both fundamental and applied topics, with research projects clustered in four major themes: AGR, Magnox and exotic spent fuels; PuO{sub 2} and fuel residues; legacy ponds and silo wastes; and structural integrity. The consortium builds upon and consolidates the work of previous Research Councils' UK Energy Programme-funded projects in the same field although, importantly, this new project draws in researchers from a larger group of universities and increases the multi-disciplinary nature of the group. All participating research groups have a strong track-record of supporting the nuclear industry through basic and applied research as well as consultancy activities. Key aims of the consortium are to extend and develop a relevant academic skill base in the UK associated with the needs of the nuclear waste management industry, to train the next generation of UK researchers, equipping them with skills and experiences relevant to nuclear waste management and decommissioning issues, and to carry out cutting-edge research that has the potential to provide new and innovative pathways to better management of both legacy and future nuclear wastes. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Powders and pellets – Extrusion engineering for a Cu/BEA syngas-to-hydrocarbons catalyst
Converting high-performing powder catalysts from the laboratory reactor scale into effective extruded catalysts at the industrial scale remains a hurdle for advancing sustainable catalytic processes, such as the conversion of biogenic syngas into high octane gasoline. Recently, a process-intensified syngas-to-hydrocarbons (STH) reaction in a single reactor under relatively mild conditions (220–250 ºC, 0.75–2.0 MPa) was reported, enabled by the development of a dimethyl ether (DME) homologation catalyst, Cu-modified H-BEA (Cu/BEA) zeolite. In this study, we explore approaches for synthesizing engineered Cu/BEA catalysts for use in the STH reaction to retain the high performance observed with the powder catalyst. We demonstrate that changes to the order of manufacturing steps (i.e., Cu deposition, alumina binder addition, and extrusion) result in observable changes to key active sites (Brønsted acid sites and zeolitic Cu + species), and ultimately, catalyst performance. When the Cu precursor was added directly to BEA before extrusion, both types of active sites were stabilized, preserving the activity of the powder catalyst. However, when the Cu precursor was added after extrusion, the resulting Cu species were mobile, destabilizing Brønsted acid sites and leading to near-zero activity.
09 BIOMASS FUELS↗
Propane Dehydrogenation on Single-Site [PtZn4] Intermetallic Catalysts
Propane dehydrogenation (PDH) is a commercial propylene production technology that has received much attention, but high reaction temperature results in decrease of propylene selectivity and catalyst stability. This paper describes a single-site [PtZn 4 ] catalyst by assembling atomically ordered intermetallic alloy (IMA) as a selective and ultrastable PDH catalyst. The catalyst enables more than 95% propylene selectivity from 520 to 620 oC. No obvious deactivation is observed within 160-hours test, superior to PtSn/Al 2 O 3 and state-of-the-art Pt-based catalysts. Additionally, based on in situ X-ray absorption fine-structure, X-ray photoelectron spectroscopy measurements and density functional theory calculations, we reveal that the surface [PtZn 4 ] ensembles in PtZn IMAs serve as the key active site structures, wherein the geometry-isolated and electron-rich Pt1 site in [PtZn 4 ] ensembles readily promotes the first and second C–H cleavage of propane, but inhibits further dehydrogenation of surface-bounded propylene. This significantly improves the selectivity and stability by prohibiting coke side reactions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
On the origins of the linear no-threshold (LNT) dogma by means of untruths, artful dodges and blind faith
This paper is an historical assessment of how prominent radiation geneticists in the United States during the 1940s and 1950s successfully worked to build acceptance for the linear no-threshold (LNT) dose–response model in risk assessment, significantly impacting environmental, occupational and medical exposure standards and practices to the present time. Detailed documentation indicates that actions taken in support of this policy revolution were ideologically driven and deliberately and deceptively misleading; that scientific records were artfully misrepresented; and that people and organizations in positions of public trust failed to perform the duties expected of them. Key activities are described and the roles of specific individuals are documented. These actions culminated in a 1956 report by a Genetics Panel of the U.S. National Academy of Sciences (NAS) on Biological Effects of Atomic Radiation (BEAR). In this report the Genetics Panel recommended that a linear dose response model be adopted for the purpose of risk assessment, a recommendation that was rapidly and widely promulgated. The paper argues that current international cancer risk assessment policies are based on fraudulent actions of the U.S. NAS BEAR I Committee, Genetics Panel and on the uncritical, unquestioning and blind-faith acceptance by regulatory agencies and the scientific community. - Highlights: • The 1956 recommendation of the US NAS to use the LNT for risk assessment was adopted worldwide. • This recommendation is based on a falsification of the research record and represents scientific misconduct. • The record misrepresented the magnitude of panelist disagreement of genetic risk from radiation. • These actions enhanced public acceptance of their risk assessment policy recommendations.
54 ENVIRONMENTAL SCIENCES↗