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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Impact of non-integer planetary revolutions on the distribution of evaporated optical coatings

Planetary substrate rotation for optical-coating deposition is evaluated based on initial and final positions for a given layer with different numbers of revolutions and various deposition-source locations. The influence of partial revolutions of the rotation system is analyzed relative to the total number of planetary revolutions in that layer to determine the relative impact on film thickness and uniformity. Furthermore, guidance is provided on the necessary planetary revolutions that should take place in each layer versus the expected error level in the layer thickness for the modeled system.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Precipitation mediates sap flux sensitivity to evaporate demand in the neotropics, Oecologia: Dataset

Using measurements in 34 tree species at seven sites across a precipitation gradient in the neotropics, we determined how the maximum sap flux velocity (vmax) and the VPD threshold at which vmax is reached (VPDmax) vary with precipitation regime (long-term annual precipitation, MAP; seasonal drought intensity, PDRY) and two functional traits related to foliar and wood economics spectra (leaf mass per area, LMA; wood specific gravity, WSG). This study demonstrates that long-term precipitation plays an important role in the sapflux response of humid tropical forests to VPD.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Predicting Ga and Cu Profiles in Co-Evaporated Cu(In,Ga)Se 2 Using Modified Diffusion Equations and a Spreadsheet

Cu(In,Ga)Se 2 (CIGS) photovoltaic absorbers frequently develop Ga gradients during growth. These gradients vary as a function of growth recipe, and are important to device performance. Prediction of Ga profiles using classic diffusion equations is not possible because In and Ga atoms occupy the same lattice sites and thus diffuse interdependently, and there is not yet a detailed experimental knowledge of the chemical potential as a function of composition that describes this interaction. Here, we show how diffusion equations can be modified to account for site sharing between In and Ga atoms. The analysis has been implemented in an Excel spreadsheet, and outputs predicted Cu, In, and Ga profiles for entered deposition recipes. A single set of diffusion coefficients and activation energies are chosen, such that simulated elemental profiles track with published data and those from this study. Extent and limits of agreement between elemental profiles predicted from the growth recipes and the spreadsheet tool are demonstrated.

14 SOLAR ENERGY↗
DOE OSTI2016

Land-total and Ocean-total Precipitation and Evaporation from a Community Atmosphere Model version 5 Perturbed Parameter Ensemble

This document presents the large scale water budget statistics of a perturbed input-parameter ensemble of atmospheric model runs. The model is Version 5.1.02 of the Community Atmosphere Model (CAM). These runs are the “C-Ensemble” described by Qian et al., “Parametric Sensitivity Analysis of Precipitation at Global and Local Scales in the Community Atmosphere Model CAM5” (Journal of Advances in Modeling the Earth System, 2015). As noted by Qian et al., the simulations are “AMIP type” with temperature and sea ice boundary conditions chosen to match surface observations for the five year period 2000-2004. There are 1100 ensemble members in addition to one run with default inputparameter values.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Cooling Tower (Evaporative Cooling System) Measurement and Verification Protocol

This measurement and verification (M and V) protocol provides procedures for energy service companies (ESCOs) and water efficiency service companies (WESCOs) to determine water savings resulting from water conservation measures (WCMs) in energy performance contracts associated with cooling tower efficiency projects. The water savings are determined by comparing the baseline water use to the water use after the WCM has been implemented. This protocol outlines the basic structure of the M and V plan, and details the procedures to use to determine water savings.

13 HYDRO ENERGY↗
DOE OSTI2017

Cooling Tower (Evaporative Cooling System) Measurement and Verification Protocol

This measurement and verification (M and V) protocol provides procedures for energy service companies (ESCOs) and water efficiency service companies (WESCOs) to determine water savings resulting from water conservation measures (WCMs) in energy performance contracts associated with cooling tower efficiency projects. The water savings are determined by comparing the baseline water use to the water use after the WCM has been implemented. This protocol outlines the basic structure of the M and V plan, and details the procedures to use to determine water savings.

13 HYDRO ENERGY↗
DOE OSTI2019

Scoping Studies to Determine Impact of a Low-Alkali Phase Separated Frit on the Behavior of the Frit Slurry and Slurry Mix Evaporator Rheology

The frits used in the vitrification process at the Defense Waste Processing Facility (DWPF) are alkali borosilicate glasses, which are composed mainly of B 2 O 3 , alkali (Li 2 O and Na 2 O) and SiO 2 . As the total alkali concentration in a borosilicate glass is reduced, liquid-liquid immiscibility is exhibited by the glassforming melt, which is analogous to the behavior of oil and water. Upon cooling, the resulting glass matrix is said to be phase separated. The immiscible region is controlled by both composition and temperature. Viscosity of the melt is also a factor as it impacts the reaction rate (kinetics) of phase separation. The reaction rate (kinetics) leading to phase separation is slow for higher viscosity melts, and if such a melt is cooled rapidly (e.g., quenched in water), the resulting glass could be homogeneous, or the scale of the phase separated microstructure could be of no practical significance. Phase separated alkali borosilicate glasses tend to form a more durable silica-rich phase and a less durable alkali borate-rich phase. The overall durability of the phase separated glass depends on the morphology (physical arrangements) of each of these phases. For example, droplets of the alkali borate-rich phase may form within a silicate rich matrix, which would be a more durable glass than a glass with an interconnected alkali borate-rich phase.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

The use of soil moisture and Standardized Evaporative Stress Ratio (SESR) anomalies for increased lead time of the development flash drought and heat waves

Drought and rapid intensification of drought (i.e., flash drought) can have significant impacts on the natural environment and the economy, particularly when coupled with a period(s) of extreme heat (Otkin et al., 2018). The development and/or intensification of drought falls squarely in the sub-seasonal to seasonal (S2S) time frame, which dictates that drought development, intensification, and propagation could be an output of a subseasonal or seasonal forecast. Current S2S forecasts have poor skill for forecasting the development of extreme drought and heat waves.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Np-237 LoD Measurement by TIMS-Multi-Ion Counting Total Evaporation [Poster]

Requests for ultra-low-level 237 Np analyses highlight the importance of a robust chemical purification and measurement technique for Np. In FY2022, LANL is quantifying the instrumental 237 Np LoD. Need to incorporate a chemical purification procedure for TIMS-MICTE sample preparation. What is the recovery of the chemical purification procedure? What is the ultimate detection limit that can be achieved while incorporating a chemical purification procedure? We have adapted and refined the Pu TIMS-MICTE method for Np analyses. We have determined expected uncertainties for 237 Np TIMS-MICTE measurements. We have increased sensitivity through technique improvements. We have improved method reliability for Np analyses and increased throughput. Apply knowledge gained from progress made in FY2022 to further develop Np sample purification and analyses by TIMSMICTE.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Investigation of Methane Generation Rates from Simulated and Radioactive Waste at Evaporator Conditions

Savannah River National Laboratory researchers have performed 9 experiments with simulated waste and 13 experiments with radioactive waste to determine methane generation rates (MGR) applicable to Savannah River Site waste at temperatures greater than or equal to 100 °C. Data from these experiments was used to generate temperature-dependent expressions to conservatively account for methane generation at elevated temperatures. Measured MGRs and the derived expressions are reported in units of standard cubic feet per hour per gallon of solution, where standard conditions are 25 °C and 1 atm.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Organic Evaporation, Oxidation, and Hydrolysis Testing in Support of Hanford Sample-and-Send

The Hanford site has approximately 56 million gallons of radioactive mixed waste stored in 156 unretrieved underground storage tanks. The Hanford Waste Treatment and Immobilization Plant (WTP) is being built to treat and immobilize the tank waste. The baseline method for immobilization of Low Activity Waste (LAW) through the WTP is vitrification, but additional immobilization capacity is needed to supplement the initial LAW melters. An alternative cementitious waste form is being investigated for that future immobilization method. However, one impediment to a cementitious waste form is the presence of Land Disposal Restricted (LDR) organic chemicals in tank waste, which are regulated on a concentration-based standard in the final waste form. Hence, if the quantity of organics in LAW is high enough, they must be destroyed or removed to make a waste form compatible with disposal in a mixed low level waste landfill. This work evaluates potential avenues for treatment of LDR organics to eliminate the impediment and permit possible use of a cementitious waste form.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗