Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Lighting”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Chiral light-front perturbation theory and the flavor dependence of the light-quark nucleon sea

The light-quark flavor dependence of the proton sea has been of great interest for many years because of its close connection with nonperturbative effects. One hypothesis is that this dependence arises from the pion cloud of the proton. Here, we apply light-cone perturbation theory and experimental constraints to a chiral Lagrangian to compute the relevant Fock-space components of the nucleon wave function with well-defined uncertainties. Existing experimental information regarding the light-flavor sea is studied and predictions for future experimental results are provided. Future experiments have the ability to rule out this hypothesis and have profound implications for understanding the nucleon-nucleon force.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Penning plasma based simultaneous light emission source of visible and VUV lights

In this paper, a laboratory-based penning plasma discharge source is reported which has been developed in two anode configurations and is able to produce visible and VUV lights simultaneously. The developed source has simultaneous diagnostics facility using Langmuir probe and optical emission spectroscopy. The two anode configurations, namely, double ring and rectangular configurations, have been studied and compared for optimum use of the geometry for efficient light emissions and recording. The plasma is produced using helium gas and admixture of three noble gases including helium, neon, and argon. The source is capable to produce eight spectral lines for pure helium in the VUV range from 20 to 60 nm and total 24 spectral lines covering the wavelength range 20–106 nm for the admixture of gases. The large range of VUV lines is generated from gaseous admixture rather from the sputtered materials. The recorded spectrum shows that the plasma light radiations in both visible and VUV range are larger in double ring configuration than that of the rectangular configurations at the same discharge operating conditions. To clearly understand the difference, the imaging of the discharge using ICCD camera and particle-in-cell simulation using VORPAL have also been carried out. The effect of ion diffusion, metastable collision with the anode wall and the nonlinear effects are correlated to explain the results.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Disordered spontaneously buckled optical gratings for improved lighting applications

Technologies for directing daylight deeper within a building space are highly sought after for energy efficiency applications in order to offset artificial lighting costs and to improve workplace productivity via the use of natural light. Vertical window coatings that can perform this task by redistributing sunlight deeper into a space are especially attractive as they are significantly more straightforward to incorporate into a wide variety of architectures as well as to retrofit into existing facades as compared to roof-based skylights or bulky horizontal daylight shelf type options. The potential energy savings are even greater when one takes into account the fact that such technologies would mitigate harsh glare, allowing window shades to be open for longer portions of the day. However, low-cost and readily scalable techniques are essential for widespread adoption of these window coating technologies. Here, we describe a potentially low-cost method to create a window coating that could enhance daylight penetration, requiring only a thin film of polymeric material deposited on an elastomeric substrate. The resulting structure is a disordered, spontaneously buckled optical grating that spreads incident light without noticeable chromatic dispersion due to its stochastic patterning. The described method has the potential to improve energy efficiency and while maintaining acceptable optical clarity.

De Vetter, Brent M.↗
DOE OSTI2016

Tuning the light in senior care: Evaluating a trial LED lighting system at the ACC Care Center in Sacramento, CA

This report summarizes the results from a trial installation of light-emitting diode (LED) lighting systems in several spaces within the ACC Care Center in Sacramento, CA. The Sacramento Municipal Utility District (SMUD) coordinated the project and invited the U.S. Department of Energy (DOE) to document the performance of the LED lighting systems as part of a GATEWAY evaluation. DOE tasked the Pacific Northwest National Laboratory (PNNL) to conduct the investigation. SMUD and ACC staff coordinated and completed the design and installation of the LED systems, while PNNL and SMUD staff evaluated the photometric performance of the systems. ACC staff also track behavioral and health measures of the residents; some of those results are reported here, although PNNL staff were not directly involved in collecting or interpreting those data. The trial installation took place in a double resident room and a single resident room, and the corridor that connects those (and other) rooms to the central nurse station. Other spaces in the trial included the nurse station, a common room called the family room located near the nurse station, and the ACC administrator’s private office.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

A Case Study of Luminaire-Level Lighting Control: Lighting the Northwest Energy Efficiency Alliance (NEEA) Office in Portland, OR

What happens when advanced lighting and control systems are installed in the real world? Are the advantages and energy savings realized? By observing the design, installation, commissioning, and ongoing use of connected lighting systems in real-world settings, it is possible to identify the strengths, challenges, and points of human-technology interaction that may be new or unfamiliar to those responsible for implementing or maintaining the lighting system. Ultimately, understanding and experiencing each stakeholder’s interaction with the technology can allow the research team to synthesize feedback for manufacturers, improve industry understanding of the technology, and increase adoption. The Northwest Energy Efficiency Alliance (NEEA) office in Portland, OR, is a single-floor installation that puts tunable-white, interoperability, and luminaire-level advanced control capabilities to the test. Compared to simpler, “out-of-the-box” systems that minimize field-adjustable settings, the system utilized in this space allowed for granular field adjustments which required the system specifier, client, and programming agent to make additional decisions regarding system operation while the system was being programmed. This report communicates the observational findings from the installation, programming, and ongoing operation of an advanced office LLLC system.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Green Light Emitting Diodes for the Ultimate Solid-state Lighting

Light-emitting diodes (LEDs), in particular InGaN-based LED devices, have achieved remarkable success in solid-state lighting, contributing to 25% of energy savings already. However, more than two thirds of the electricity is still lost as heat in current white LEDs today. Furthermore, expected population growth and increasing demand for lighting necessitate a more efficient approach, which can only be realized by solving the issue of the green gap (i.e., the inefficiency of the state-of-the-art green LEDs). This green gap is a fundamentally limiting issue in conventional hexagonal nitride LEDs, leading to 19% wall-plug efficiency (WPE) at 100 A/cm 2 , while the department of energy goal is 30% (in 2025) and 55% (in 2035).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1973

Light shift and light broadening in the Rb-87 maser.

A description of measurements of light-shift and light-broadening parameters for an Rb-87 maser operating between the field independent levels is reported. A parallel study of the spectral profile of the D1 pumping line is described. Comparison between the experimental results and theoretical calculations, taking into account the spatial inhomogeneity of the pumping light in the absorption cell, is presented.

Busca, G.↗
NASA NTRS2003

Vertical Profiles of Light Scattering, Light Absorption, and Single Scattering Albedo during the Dry, Biomass Burning Season in Southern Africa and Comparisons of In Situ and Remote Sensing Measurements of Aerosol Optical Depths

Airborne in situ measurements of vertical profiles of aerosol light scattering, light absorption, and single scattering albedo (omega (sub 0)) are presented for a number of locations in southern Africa during the dry, biomass burning season. Features of the profiles include haze layers, clean air slots, and marked decreases in light scattering in passing from the boundary layer into the free troposphere. Frequency distributions of omega (sub 0) reflect the strong influence of smoke from biomass burning. For example, during a period when heavy smoke was advected into the region from the north, the mean value of omega (sub 0) in the boundary layer was 0.81 +/- 0.02 compared to 0.89 +/- 0.03 prior to this intrusion. Comparisons of layer aerosol optical depths derived from the in situ measurements with those measured by a Sun photometer aboard the aircraft show excellent agreement.

Magi, Brian I.↗
NASA NTRS2011

Long-Term Changes in Light Scattering in Chesapeake Bay Inferred from Secchi Depth, Light Attenuation, and Remote Sensing Measurements

The relationship between the Secchi depth (Z(sub SD)) and the diffuse attenuation coefficient for photosynthetically active radiation (K(sub d)(PAR)), and in particular the product of the two, Z(sub SD) X K(sub d)(PAR), is governed primarily by the ratio of light scattering to absorption. We analyzed measurements of Z(sub SD) and K(sub d)(PAR) at main stem stations in Chesapeake Bay and found that the Z(sub SD) X K(sub d)(PAR) product has declined at rates varying from 0.020 to 0.033 /yr over the 17 to 25 years of measurement, implying that there has been a long -term increase in the scattering-to-absorption ratio. Remote sensing reflectance at the green wavelength most relevant to Z(sub SD) and K(sub d)(PAR) in these waters, R(sub rs)(555), did not exhibit an increasing trend over the 10 years of available measurements. To reconcile the observations we constructed a bio-optical model to calculate Z(sub SD), K(sub d)(PAR), Z(sub SD) X K(sub d)(PAR), and R(sub rs)(555) as a function of light attenuating substances and their mass-specific absorption and scattering coefficients. When simulations were based exclusively on changes in concentrations of light attenuating substances, a declining trend in Z(sub SD) E K(sub d) entailed an increasing trend in R(sub rs)(555), contrary to observations. To simulate both decreasing Z(sub SD) X K(sub d)(PAR) and stationary R(sub rs)(555), it was necessary to allow for a declining trend in the ratio of backscattering to total scattering. Within our simulations, this was accomplished by increasing the relative proportion of organic detritus with high mass-specific scattering and low backscattering ratio. An alternative explanation not explicitly modeled is an increasing tendency for the particulate matter to occur in large aggregates. Data to discriminate between these alternatives are not available.

Gallegos, Charles L.↗
DOE OSTI2013

Semiconductor light-emitting devices having concave microstructures providing improved light extraction efficiency and method for producing same

A conventional semiconductor LED is modified to include a microlens layer over its light-emitting surface. The LED may have an active layer including at least one quantum well layer of InGaN and GaN. The microlens layer includes a plurality of concave microstructures that cause light rays emanating from the LED to diffuse outwardly, leading to an increase in the light extraction efficiency of the LED. The concave microstructures may be arranged in a substantially uniform array, such as a close-packed hexagonal array. The microlens layer is preferably constructed of curable material, such as polydimethylsiloxane (PDMS), and is formed by soft-lithography imprinting by contacting fluid material of the microlens layer with a template bearing a monolayer of homogeneous microsphere crystals, to cause concave impressions, and then curing the material to fix the concave microstructures in the microlens layer and provide relatively uniform surface roughness.

42 ENGINEERING↗
DOE OSTI2016

Organic light emitting diode with light extracting layer

A light extraction substrate includes a glass substrate having a first surface and a second surface. A light extraction layer is formed on at least one of the surfaces. The light extraction layer is a coating, such as a silicon-containing coating, incorporating nanoparticles.

36 MATERIALS SCIENCE↗
DOE OSTI2019

System for outputting a spectrum of light of a scene having optical detectors to receive light of different spectral transmittance from respective filters

Technologies pertaining to a compressive sensing snapshot spectrometer are described herein. Light is focused through an array of filters onto an array of optical detectors by way of an optical objective. Each detector in the array receives light from a single respective filter in the filters. Each filter in the filters has a spectral transmittance function that overlaps a spectral transmittance function of at least one other filter. A compressive sensing algorithm is executed over outputs of the detectors based upon the known spectral transmittance functions of the filters. Based upon the execution of the compressive sensing algorithm, intensity values of the light are identified for a number of spectral bins that is greater than a number of detectors in the array.

Shields, Eric A.↗
DOE OSTI2022

Autonomous light management system for a window and method of controlling light transmission

An autonomous light management system for a window includes an electrochromic film stack comprising an electrochromic layer on a first transparent electrode, an ion storage layer on a second transparent electrode, and an electrolyte sandwiched between the ion storage and electrochromic layers. The electrochromic film stack exhibits a transmissive state or an absorptive state depending on charging or discharging of the electrochromic layer. The light management system further comprises an array of power units disposed on a front surface of the electrochromic film stack, where each power unit comprises at least one solar microcell. Collectively, the solar microcells cover an area no greater than about 6% of a total area of the front surface. The array of power units is configured to control the charging and discharging of the electrochromic layer, thereby manipulating light transmission through the electrochromic film stack.

Yoder, Mikayla A.↗
DOE OSTI2025

Measurement of light-by-light scattering and the Breit-Wheeler process, and search for axion-like particles in ultraperipheral PbPb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

Measurements of light-by-light scattering (LbL, γγ → γγ) and the Breit-Wheeler process (BW, γγ → e + e − ) are reported in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV. The data sample, corresponding to an integrated luminosity of 1.7 nb −1 , was collected by the CMS experiment at the CERN LHC in 2018. Events with an exclusively produced γγ or e + e − pair with invariant masses m γγ,ee > 5 GeV, along with other fiducial criteria, are selected. The measured BW fiducial production cross section, σ fid (γγ → e + e − ) = 263.5 ± 1.8(stat) ± 17.8(syst) μb, as well as the differential distributions for various kinematic observables, are in agreement with leading-order quantum electrodynamics predictions complemented with final-state photon radiation. The measured differential BW cross sections allow discrimination between different theoretical descriptions of the photon flux of the lead ion. In the LbL final state, 26 exclusive diphoton candidate events are observed compared with 12.0 ± 2.9 expected for the background. Combined with previous results, the observed significance of the LbL signal with respect to the background-only hypothesis is above five standard deviations. The measured fiducial LbL scattering cross section, σ fid (γγ → γγ) = 107 ± 24(stat) ± 13(syst) nb, is in agreement with next- to-leading-order predictions. Limits on the production of axion-like particles coupled to photons are set over the mass range 5–100 GeV, including the most stringent limits to date in the range of 5–10 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Spatial heterogeneity analysis of the effects of urbanization on airport CO2 emissions in China - A geographically weighted approach using nighttime light data

Regional disparities in carbon dioxide (CO2) emissions from airports at the city level are of increasing importance for low-carbon development of the civil aviation sector. However, CO2 emissions from airport operations have rarely been estimated and discussed. We investigate the main driving forces of airport CO2 emissions by using Ordinary Least Square (OLS) and Geographically Weighted Regression (GWR) models, separately, to investigate whether urbanization drives airport CO2 emissions and to investigate spatial heterogeneity at the city level. Nighttime light (NTL) data from satellite observations are adopted as a proxy for urbanization. We obtained energy consumption data by end-use purpose for 70 airports in China and calculated the CO2 emissions from on-ground airport operations. The median CO2 emissions of the 70 sample airports are estimated to be 15.9 million tonnes for 2015. Results from the GWR model indicate that airport CO2 emissions are affected by five main factors: urbanization, foreign direct investment, the share of tertiary industry in gross domestic output, passenger turnover of civil aviation and passenger turnover of railways. The elasticity of urbanization shows an increasing trend from the east of China to the west. The spatial heterogeneity of the CO2 emissions of the five airport clusters that are located in five urban agglomerations is discussed. In order to achieve effective reductions of CO2 emissions from airports, policy-makers should consider the spatial heterogeneity of the major driving factors of carbon emissions in different regions to avoid carbon lock-in.

Airport CO2 emissions↗