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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 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Volatility basis-set approach simulation of organic aerosol formation in East Asia: implications for anthropogenic-biogenic interaction and controllable amounts

Organic aerosol (OA) simulations using the volatility basis-set approach were made for East Asia and its outflow region. Model simulations were evaluated through comparisons with OA measured by aerosol mass spectrometers in and around Tokyo (at Komaba and Kisai in summer 2003 and 2004) and over the outflow region in East Asia (at Fukue and Hedo in spring 2009). The simulations with aging processes of organic vapors reasonably well reproduced mass concentrations, temporal variations, and formation efficiency of observed OA at all sites. As OA mass was severely underestimated in the simulations without the aging processes, the oxidations of organic vapors are essential for reasonable OA simulations over East Asia. By considering the aging processes, simulated OA concentrations considerably increased from 0.24 to 1.28 µg m-3 in the boundary layer over the whole of East Asia. OA formed from the interaction of anthropogenic and biogenic sources was also enhanced by the aging processes. The fraction of controllable OA was estimated to be 87 % of total OA over the whole of East Asia, showing that most of the OA in our simulations formed anthropogenically (controllable). A large portion of biogenic secondary OA (78 % of biogenic secondary OA) formed through the influence of anthropogenic sources. The high fraction of controllable OA in our simulations is likely because anthropogenic emissions are dominant over East Asia and OA formation is enhanced by anthropogenic sources and their aging processes. Both the amounts (from 0.18 to 1.12 µg m-3) and the fraction (from 75 % to 87 %) of controllable OA were increased by aging processes of organic vapors over East Asia.

Matsui, H.↗
DOE OSTI2023

Simulating organic aerosol in Delhi with WRF-Chem using the volatility-basis-set approach: exploring model uncertainty with a Gaussian process emulator

The nature and origin of organic aerosol in the atmosphere remain unclear. The gas–particle partitioning of semi-volatile organic compounds (SVOCs) that constitute primary organic aerosols (POAs) and the multigenerational chemical aging of SVOCs are particularly poorly understood. The volatility basis set (VBS) approach, implemented in air quality models such as WRF-Chem (Weather Research and Forecasting model with Chemistry), can be a useful tool to describe emissions of POA and its chemical evolution. However, the evaluation of model uncertainty and the optimal model parameterization may be expensive to probe using only WRF-Chem simulations. Gaussian process emulators, trained on simulations from relatively few WRF-Chem simulations, are capable of reproducing model results and estimating the sources of model uncertainty within a defined range of model parameters. In this study, a WRF-Chem VBS parameterization is proposed; we then generate a perturbed parameter ensemble of 111 model runs, perturbing 10 parameters of the WRF-Chem model relating to organic aerosol emissions and the VBS oxidation reactions. This allowed us to cover the model's uncertainty space and to compare outputs from each run to aerosol mass spectrometer observations of organic aerosol concentrations and O:C ratios measured in New Delhi, India. The simulations spanned the organic aerosol concentrations measured with the aerosol mass spectrometer (AMS). However, they also highlighted potential structural errors in the model that may be related to unsuitable diurnal cycles in the emissions and/or failure to adequately represent the dynamics of the planetary boundary layer. While the structural errors prevented us from clearly identifying an optimized VBS approach in WRF-Chem, we were able to apply the emulator in the following two periods: the full period (1–29 May) and a subperiod period of 14:00–16:00 h LT (local time) on 1–29 May. The combination of emulator analysis and model evaluation metrics allowed us to identify plausible parameter combinations for the analyzed periods. We demonstrate that the methodology presented in this study can be used to determine the model uncertainty and to identify the appropriate parameter combination for the VBS approach and hence to provide valuable information to improve our understanding of OA production.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

TROPOS pyranometer network (PyrNet) observational data set collected during the S2VSR field campaign

During the Small-Scale Variability of Solar Radiation field campaign (S2VSR), a unique sensor network consisting of 60 autonomous pyranometer stations was deployed for a 12-week period at the ARM Southern Great Plains observatory. Stations have been distributed across a 4x4 to 6x6 km2 domain surrounding the Central Facility. Each station has recorded global radiation together with air temperature and relative humidity with a sampling frequency of 1-Hz. The network has provided a data set with an unprecedented level of detail of the small-scale variability of global solar radiation at the surface, resolving fluctuations down to the second- and decameter-scale.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Expression of a set of glial cell-specific markers in the Drosophila embryonic central nervous system

The types of glia in the central nervous system (CNS) of the Drosophila embryo include longitudinal glia (LG), cell body glia (CBG), and peripheral glia (PG). Transcription factors, such as glial cell missing and reverse polarity, are well-established general glial cell markers. Only a few glial cell-specific markers have been identified in the Drosophila embryonic CNS, thus far. In the present study, we employed the glial cell-specific markers for LG (vir-1/CG5453 and CG31235), CBG (fabp/CG6783 and CG11902), and PG (CG2310 and moody/CG4322), and comprehensively analyzed their expression patterns, during the embryonic CNS development. Our study validated the specificity of a set of glial markers, and further revealed their spatio-temporal expression patterns, which will aid in the understanding of the developmental lineage, and investigating their role in the development and homeostasis of the Drosophila CNS in vivo.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Climate and hydraulic traits interact to set threshold for liana viability

This collection contains the datasets required to reproduce the analysis and figures for the publication titled "Climate and hydraulic traits interact to set thresholds for liana viability" by Willson et al. The CSV titled "extended_met_analysis_data_8_Feb.csv" contains the processed dataset from our extended meta-analysis of tropical tree and liana hydraulic traits. The CSV titled "filtered_TRY_analysis_16-03-21.csv" contains the processed dataset from our TRY analysis of functional traits of tropical trees and lianas. The zip file titled "TRY.zip" contains the raw data files downloaded from the TRY database, from which we derived our processed TRY dataset.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Wet Chemical Compositional and Near IR Spectra Data Sets for Biomass

Near-infrared (NIR) calibration models are created by applying multivariate calibration methods to the combination of wet chemistry data and NIR spectra of a given set of biomass samples. Wet chemical compositional data and NIR spectra exist for the following types of biomass samples: corn stover, switchgrass, mixed hardwoods, mixed softwoods, sorghum, and miscanthus. These samples may be feedstock samples, washed and dried solids from one or more pretreatment processes, liquors derived from one or more pretreatment processes, or whole pretreated slurries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗