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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Identifying Periodic Variable Stars and Eclipsing Binary Systems with Long-term Las Cumbres Observatory Photometric Monitoring of ZTF J0139+5245

We present the results of our search for variable stars using the long-term Las Cumbres Observatory (LCO) monitoring of white dwarf ZTF J0139+5245 with the two 1.0 m telescope nodes located at McDonald Observatory using the Sinistro imaging instrument. In this search, we find 38 variable sources, of which 27 are newly discovered or newly classified (71%) based on comparisons with previously published catalogs, thereby increasing the number of detections in the field of view under consideration by a factor of ≈2.5. We find that the improved photometric precision per exposure due to longer exposure time for LCO images combined with the greater time sampling of LCO photometry enables us to increase the total number of detections in this field of view. Each LCO image covers a field of view of 26' × 26' and observes a region close to the Galactic plane (b = -9.°4) abundant in stars with an average stellar density of ≈8 arcmin{sup -2}. We perform aperture photometry and Fourier analysis on over 2000 stars across 1560 LCO images spanning 537 days to find 28 candidate BY Draconis variables, three candidate eclipsing binaries of type EA, and seven candidate eclipsing binaries of type EW. In assigning preliminary classifications to our detections, we demonstrate the applicability of the Gaia color–magnitude diagram as a powerful classification tool for variable-star studies.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

2020 Mitigation and Monitoring Report for the Arroyo Las Positas Management Project

This report describes maintenance, monitoring, and mitigation conducted in 2020 as part of the Arroyo Las Positas Management Project (the project) at Lawrence Livermore National Laboratory’s (LLNL’s) Livermore Site. The purpose of this project is to enhance habitat value for the California red-legged frog (Rana draytonii) within the LLNL reach of Arroyo Las Positas and protect LLNL facilities from flooding. The project description, in addition to the monitoring and mitigation requirements for this project are described in the October 2015 Revised Mitigation and Monitoring Plan for the Arroyo Las Positas Management Project (MMP) and the Formal Consultation on the Proposed Arroyo Maintenance Project on Arroyo Las Positas at Lawrence Livermore National Laboratory (biological opinion; Service File Numbers 1-1-97-F-173 and 1-1-98-I-1562).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Interseismic Strain Accumulation between the Colorado Plateau and the Eastern California Shear Zone: Implications for the Seismic Hazard near Las Vegas, Nevada

ABSTRACT Crustal deformation in the central Basin and Range between the Colorado plateau and the Eastern California Shear Zone is active but slow, making it a challenge to assess how strain is distributed and crustal motion transferred. However, knowledge of strain rates is very important, particularly for addressing the seismic hazard for both the Las Vegas urban area and the site of the proposed Yucca Mountain nuclear waste repository, in southern Nevada. Global Positioning System (GPS) data provide important constraints, particularly now that the GPS network in the area has substantially expanded in recent years. However, because deformation is slow, it is important to mitigate any transient tectonic and nontectonic signals to obtain the most accurate long-term interseismic motion and robust estimation of strain rates. We use data from all GPS stations in the region including both long-running continuous and semicontinuous stations. We model and remove postseismic displacements at these stations using source parameters for 41 events, dating back to the 1700 Cascadia megathrust earthquake, which contribute significantly to the deformation field within the central Basin and Range. We also remove correlated noise from the time series with the common-mode component imaging technique. We find that removal of both the postseismic transients and common-mode noise substantially reduces the uncertainties and spatial variation in the velocities. We find east–west extension across the Las Vegas Valley of 0.5–0.6 mm/yr. The interseismic strain rate field, calculated with the final velocities, reveals higher strain rates through southern Nevada than in previous studies, with rates within Las Vegas Valley of 8.5±2.4×10−9 yr−1. Our results also confirm shear along the Pahranagat shear zone, but the estimated amplitude is strongly affected by postseismic relaxation.

Geochemistry & Geophysics↗
DOE OSTI2020

Materials Data on LaS by Materials Project

LaS crystallizes in the orthorhombic Cmce space group. The structure is two-dimensional and consists of two LaS sheets oriented in the (0, 0, 1) direction. La2+ is bonded to five equivalent S2- atoms to form a mixture of edge and corner-sharing LaS5 square pyramids. There are four shorter (2.91 Å) and one longer (2.93 Å) La–S bond lengths. S2- is bonded to five equivalent La2+ atoms to form a mixture of edge and corner-sharing SLa5 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2023

El valor de los metadatos para las estaciones de recuperación de recursos del agua

Spanish: Los metadatos hacen referencia a información descriptiva (como ubicación del sensor, unidad de medida, rango de medida, fecha de calibración, fecha de limpieza, si ocurrió algún evento como episodio de lluvia/fallo operativo/vertido tóxico . . .) que es esencial para convertir los grandes volúmenes de datos que se recogen actualmente en las instalaciones de tratamiento de agua y que están sin procesar en información y recursos útiles. Con el avance de la digitalización en el sector del agua, es fundamental evitar los cementerios de datos y, por otro lado, utilizar los datos almacenados para resolver problemas actuales y futuros. Este artículo se centra en el papel crucial que tienen los metadatos para responder a desafíos futuros y posiblemente impredecibles. El objetivo de este documento es presentar el ‘reto de los metadatos’ y destacar la necesidad de tener en cuenta los metadatos cuando se recoge información como parte de las buenas prácticas de digitalización. English: Metadata refers to descriptive information (such as sensor location, measurement unit, measurement range, calibration date, cleaning date, if any event occurred such as rain event/operating failure/toxic spill, . . .) essential to convert large volumes of raw data that are currently collected at water treatment facilities into useful information and resources. With the advance of digitalization in the water sector, it is fundamental to avoid data graveyards and, on the other hand, using collected data to address current and future problems. This paper focuses on the crucial role that metadata has in responding to future and possibly unpredictable challenges. The aim of this document is to present the ‘metadata challenge’ and to highlight the need to consider metadata when collecting information as part of good digitalization practices.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Monitoring changes in human activity during the COVID-19 shutdown in Las Vegas using infrasound microbarometers

While studies of urban acoustics are typically restricted to the audio range, anthropogenic activity also generates infrasound (<20 Hz, roughly at the lower end of the range of human hearing). Shutdowns related to the COVID-19 pandemic unintentionally created ideal conditions for the study of urban infrasound and low frequency audio (20–500 Hz), as closures reduced human-generated ambient noise, while natural signals remained relatively unaffected. An array of infrasound sensors deployed in Las Vegas, NV, provides data for a case study in monitoring human activity during the pandemic through urban acoustics. The array records a sharp decline in acoustic power following the temporary shutdown of businesses deemed nonessential by the state of Nevada. This decline varies spatially across the array, with stations close to McCarran International Airport generally recording the greatest declines in acoustic power. Further, declines in acoustic power fluctuate with the time of day. As only signals associated with anthropogenic activity are expected to decline, this gives a rough indication of periodicities in urban acoustics throughout Las Vegas. This study's results reflect the city's response to the pandemic and suggest spatiotemporal trends in acoustics outside of shutdowns.

58 GEOSCIENCES↗
DOE OSTI2022

Modeling Urban Acoustic Noise in the Las Vegas, NV Region

Ambient infrasound noise in quiet, rural environments has been extensively studied and well-characterized through noise models for several decades. More recently, creating noise models for high-noise rural environments has also become an area of active research. However, far less work has been done to create generalized low-frequency noise models for urban areas. The high ambient noise levels expected in cities and other highly populated areas means that these environments are regarded as poor locations for acoustic sensors, and historically, sensor deployment in urban areas were avoided for this reason. However, there are several advantages to placing sensors in urban environments, including convenience of deployment and maintenance, and increasingly, necessity, as more previously rural areas become populated. This study seeks to characterize trends in low-frequency urban noise by creating a background noise model for Las Vegas, NV, using the Las Vegas Infrasound Array (LVIA): a network of eleven infrasound sensors deployed throughout the city. Data included in this study spans from 2019 to 2021 and provides a largely uninterrupted record of noise levels in the city from 0.1–500 Hz, with only minor discontinuities on individual stations. We organize raw data from the LVIA sensors into hourly power spectral density (PSD) averages for each station and select from these PSDs to create frequency distributions for time periods of interest . These frequency distributions are converted into probability density functions (PDFs), which are then used to evaluate variations in frequency and amplitude over daily to seasonal timescale s. In addition to PDFs, the median, 5 th percentile, and 95 th percentile amplitude values are calculated across the entire frequency range. This methodology follows a well-established process for noise model creation.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2021

Las Vegas Block Group Buildings Data

These data include a comprehensive summary of all residential and commercial buildings in the Las Vegas Assessors office dataset as it was on Feb 28th 2021. Building level data has been summarized to the US Census 2020 Block Group geographies.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2020

Materials Data on LaS by Materials Project

LaS is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. La2+ is bonded to six equivalent S2- atoms to form a mixture of edge and corner-sharing LaS6 octahedra. The corner-sharing octahedral tilt angles are 0°. All La–S bond lengths are 2.94 Å. S2- is bonded to six equivalent La2+ atoms to form a mixture of edge and corner-sharing SLa6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaS by Materials Project

LaS is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. La2+ is bonded in a body-centered cubic geometry to eight equivalent S2- atoms. All La–S bond lengths are 3.10 Å. S2- is bonded in a body-centered cubic geometry to eight equivalent La2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Passive and active peer effects in the spatial diffusion of residential solar panels: A case study of the Las Vegas Valley

This research analyzes the role of peer influences on the adoption of residential rooftop solar photovoltaic panels (PV) within the context of the Diffusion of Innovation Theory. PV literature indicates that adopters are influenced by word of mouth (WOM) information exchange with peers, i.e., active peer effects, while other studies suggest that living near households with visible rooftop PV installations influences adoption, i.e., passive peer effects. We bridge the gap in this literature by conducting a mixed methods analysis. We develop and administer a survey to Las Vegas Valley (LVV) residents to identify current and potential PV adopters' perceptions of peer-effects and consumer intention variables. We conduct a spatial analysis of Google's Project Sunroof data to identify LVV neighborhoods in the later stages of the PV diffusion process, i.e., those with the highest PV adoption rates. Key results show that current PV adopters living in early diffusion areas report significantly higher active and passive peer effects compared to adopters in later diffusion areas. Potential adopters in later diffusion areas report higher passive peer effects than those in early diffusion areas. Overall, because LVV has a low PV adoption rate (<3%), short term strategies aimed at increasing PV adoption should emphasize WOM active peer effects. Here, we caution against long-term green marketing strategies focusing solely on peer-effects as the PV market matures.

14 SOLAR ENERGY↗
DOE OSTI2025

Effectiveness of street trees in reducing air temperature and outdoor heat exposure in Las Vegas

Urban greening and especially tree planting strategies are being widely planned and implemented to mitigate urban overheating and thermal stress in many urban areas. However, the effectiveness of these strategies depends on multiple factors, including urban morphology, environmental conditions, and tree characteristics. This study investigates the effects of street tree planting strategies on air temperature and outdoor heat exposure in Las Vegas by combining an urbanized mesoscale climate model coupled to a multi-layer street tree model (Weather Research and Forecasting-BEP-Tree; Δ x = 900 m) with a microscale pedestrian heat exposure model (Temperatures of Urban Facets for Pedestrian; Δ x = 1 m). A series of simulations are conducted for July and August 2022. Large city-wide increases of a drought tolerant tree species cool air temperature mainly during the nighttime (up to 1.5 °C), with daytime effects being limited due to leaves shedding sensible instead of latent heat as stomata close in response to high vapor pressure deficits. Increased evaporative cooling is achieved with a different tree species (double at night, and reaching 0.4 °C during the day), but water requirements increase threefold. Despite their relatively small effect on air temperature during the day, trees provide significant shade by intercepting solar radiation, reducing mean radiant temperature (up to 16 °C) and enhancing outdoor thermal comfort, a major benefit of street trees in hot arid climates. The nighttime cooling of trees and the daytime reduction of radiant loading show potential to reduce the heat-related health impacts. Our results highlight the need to evaluate the effects of street trees on a case-by-case basis.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Building Parameters in Las Vegas

Csv files for 132 NUDAPT-defined building parameters for census tracts in Las Vegas, Nevada along with a reference shapefile

Sweet, Levi↗
DOE OSTI2023

Understanding Building Energy Use in Las Vegas: Basic Building Stock Characterization

This report is part of a publication series that focuses on approximately 100 different local geographies, or "clusters." Each report provides commercial and multifamily building characteristic and energy data for a local geography, with the intention of helping policymakers at the city, county and state levels better understand building energy use. Specifically, this report breaks down the building stock in the counties shown in Figure 1 by building type, size, energy consumption, and emissions.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Understanding Building Energy Use in the El Paso-Las Cruces Area: Basic Building Stock Characterization

This report is part of a publication series that focuses on approximately 100 different local geographies, or "clusters." Each report provides commercial and multifamily building characteristic and energy data for a local geography, with the intention of helping policymakers at the city, county and state levels better understand building energy use. Specifically, this report breaks down the building stock in the counties shown in Figure 1 by building type, size, energy consumption, and emissions.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗