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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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At least 1,423 records · Page 79
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

The Benefits of Global High Resolution for Climate Simulation: Process Understanding and the Enabling of Stakeholder Decisions at the Regional Scale

Many think that the time scales of the Paris Climate Agreement indicate urgent action is required on climate policies over the next few decades, in order to avoid the worst risks posed by climate change. On these relatively short time scales the combined effect of climate variability and change are both key drivers of extreme events, with decadal time scales also important for infrastructure planning. Hence, in order to assess climate risk on such time scales, we require climate models to be able to represent key aspects of both internally driven climate variability and the response to changing forcings. In this paper we argue that we now have the modeling capability to address these requirements—specifically with global models having horizontal resolutions considerably enhanced from those typically used in previous Intergovernmental Panel on Climate Change (IPCC) and Coupled Model Intercomparison Project (CMIP) exercises. The improved representation of weather and climate processes in such models underpins our enhanced confidence in predictions and projections, as well as providing improved forcing to regional models, which are better able to represent local-scale extremes (such as convective precipitation). We choose the global water cycle as an illustrative example because it is governed by a chain of processes for which there is growing evidence of the benefits of higher resolution. At the same time it comprises key processes involved in many of the expected future climate extremes (e.g., flooding, drought, tropical and midlatitude storms).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Effects of machine learning errors on human decision-making: manipulations of model accuracy, error types, and error importance

Abstract This study addressed the cognitive impacts of providing correct and incorrect machine learning (ML) outputs in support of an object detection task. The study consisted of five experiments that manipulated the accuracy and importance of mock ML outputs. In each of the experiments, participants were given the T and L task with T-shaped targets and L-shaped distractors. They were tasked with categorizing each image as target present or target absent. In Experiment 1, they performed this task without the aid of ML outputs. In Experiments 2–5, they were shown images with bounding boxes, representing the output of an ML model. The outputs could be correct (hits and correct rejections), or they could be erroneous (false alarms and misses). Experiment 2 manipulated the overall accuracy of these mock ML outputs. Experiment 3 manipulated the proportion of different types of errors. Experiments 4 and 5 manipulated the importance of specific types of stimuli or model errors, as well as the framing of the task in terms of human or model performance. These experiments showed that model misses were consistently harder for participants to detect than model false alarms. In general, as the model’s performance increased, human performance increased as well, but in many cases the participants were more likely to overlook model errors when the model had high accuracy overall. Warning participants to be on the lookout for specific types of model errors had very little impact on their performance. Overall, our results emphasize the importance of considering human cognition when determining what level of model performance and types of model errors are acceptable for a given task.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Evaluation of watershed-derived mass loads to prioritize TMDL decision-making

A total maximum daily load (TMDL) for oxygen demanding substances is being implemented in the San Joaquin River (SJR) in California (USA) due to frequently occurring low dissolved oxygen conditions. The SJR is a eutrophic river, heavily impacted by agriculture. A mass balance was developed to identify the sources of oxygen-demanding substances and nutrients to the river with the objective of providing a scientific basis for management actions needed to meet TMDL requirements. Data were collected for flow and water quality and mass loads calculated for sites within the main stem of the SJR, river inputs (tributaries), and diversions in the study area. Using a quadrant analysis, tributary flows and loads are ranked to identify targets for water quality improvement efforts. Additionally, all mass loads were summed (inputs minus diversions) and compared with observed loads at the downstream limit of the study area. The mass balance analysis identifies major contributors of mass loads and mass balance closure is assessed for each constituent. These analysis methods inform the TMDL process which includes a load allocation, and is useful for determining locations for implementation of improvement projects needed to improve the health of the river.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Decision Paper for the Disposition of FS-65 Shipping Containers, Support Equipment, and Mixed Oxide (MOX) Material Contents (Rev. 1.1)

A description of the containers, contents, and disposition alternatives follow. Table 1 provides a rough order of magnitude cost and schedule duration estimate for the 2 disposition alternatives. Cost and schedule data are rounded to two significant figures and the durations are based on 1735 working hours per year. The sub-task durations and personnel are not totaled for the tasks because many of the sub-tasks will be conducted in parallel. Once an Alternative is selected a detailed resource loaded schedule will be developed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

Decision Paper for the Disposition of FS-65 Shipping Containers, Support Equipment, and Mixed Oxide (MOX) Material Contents (Rev. 1.2)

A description of the containers, contents, and disposition alternatives follow. Table 1 provides a rough order of magnitude cost and schedule duration estimate for the 2 disposition alternatives. Cost and schedule data are rounded to two significant figures and the durations are based on 1735 working hours per year. The sub-task durations and personnel are not totaled for the tasks because many of the sub-tasks will be conducted in parallel. Once an Alternative is selected a detailed resource loaded schedule will be developed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

User's manual for the BROOM decision support system

The Building Restoration Operations Optimization Model (BROOM) software system, developed by Sandia National Laboratories, is a comprehensive system designed to improve the efficiency and quality of sample collection, data management, and interpretation. Currently, BROOM is capable of supporting sampling efforts at facilities contaminated with chemical and/or biological agents. BROOM provides advanced visualization, analysis, and sampling optimization functions, which speed up the sampling process and lower the associated sampling costs. BROOM enables the user to develop a defensible sampling plan based on statistical analysis of sample results. BROOM consists of two applications: one that runs on a hand-held PDA and one that runs on a Windows desktop/laptop. This document covers the installation and basic operation of both components and provides examples of the application of these tools during and following an actual field exercise.

Knowlton, Robert G.↗
DOE OSTI2012

Corrective Action Decision Document for Corrective Action Unit 366: Area 11 Plutonium Valley Dispersion Sites Nevada National Security Site, Nevada

The purpose of this CADD is to identify and provide the rationale for the recommendation of corrective action alternatives (CAA) for the six CASs within CAU 366. Corrective action investigation (CAI) activities were performed from October 12, 2011, to May 14, 2012, as set forth in the Corrective Action Investigation Plan for Corrective Action Unit 366: Area 11 Plutonium Valley Dispersion Sites.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Dose Assessment of LANL-Derived Residual Radionuclides in soils within Tract A-14 (Rendija Canyon) for Land Transfer Decisions

Rendija Canyon is located immediately north of the Los Alamos town site. The watershed has a drainage area of 9.5 mi 2 . The canyon head is on the flanks of the Sierra de los Valles just west of the town site at an elevation of 9826 ft. The canyon contains an ephemeral stream channel that extends approximately 9 mi east to the confluence with Guaje Canyon. The minimum elevation of the watershed is approximately 6300 ft (LANL 1997). Rendija Canyon primarily crosses US Forest Service (USFS) land except for approximately 1.6 mi of the middle portion of the canyon that crosses General Services Administration (GSA) land. Parcels of private land and Los Alamos County land, such as the Guaje Pines Cemetery, are located in Rendija Canyon along the north side of Los Alamos. One named tributary, Cabra Canyon, enters the Rendija Canyon channel from the north in the central portion of the watershed. Cabra Canyon trends northwest to southeast, is approximately 2 mi long, and has a watershed area of 1.2 mi 2 on USFS and GSA land. Three unnamed tributaries to Rendija Canyon are located west of Cabra Canyon and drain south-southeast into the main Rendija Canyon channel. These tributaries are approximately 1.5, 2.0, and 1.2 mi long (LANL 2001). Tributaries of Rendija Canyon and contain ephemeral streams. There are no effluent discharges (outfalls) in the Canyon. The watershed drains portions of Los Alamos town site, GSA land, and USFS land.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

100-N Area Decision Unit Target Analyte List Development for Soil

This report documents the process used to identify source area target analytes in support of the 100-N Area remedial investigation/feasibility study (RI/FS) addendum to the Integrated 100 Area Remedial Investigation/Feasibility Study Work Plan (DOE/RL-2008-46, Rev. 0).

100-N↗
DOE OSTI2013

Integration of Water Resource Models with Fayetteville Shale Decision Support and Information System

Significant issues can arise with the timing, location, and volume of surface water withdrawals associated with hydraulic fracturing of gas shale reservoirs as impacted watersheds may be sensitive, especially in drought years, during low flow periods, or during periods of the year when activities such as irrigation place additional demands on the surface supply of water. Significant energy production and associated water withdrawals may have a cumulative impact to watersheds over the short-term. Hence, hydraulic fracturing based on water withdrawal could potentially create shifts in the timing and magnitude of low or high flow events or change the magnitude of river flow at daily, monthly, seasonal, or yearly time scales. These changes in flow regimes can result in dramatically altered river systems. Currently little is known about the impact of fracturing on stream flow behavior. Within this context the objective of this study is to assess the impact of the hydraulic fracturing on the water balance of the Fayetteville Shale play area and examine the potential impacts of hydraulic fracturing on river flow regime at subbasin scale.

04 OIL SHALES AND TAR SANDS↗