10 research outputs found
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Hot Gas Cleanup Test Facility for Gasification and Pressurized Combustion
Efficiencies in advanced power generation systems such as integrated gasification combined cycle, pressurized fluidized bed combustion and integrated gasification fuel cells can be maximized by feeding hot fuel gas or flue gas to the power block. However, advanced gas turbines have strict particulate requirements to minimize wear on the blades due to the close tolerances used to maximize the efficiency of the turbomachinery. Molten Carbonate Fuel Cells also have strict particulate requirements to prevent blinding of the electrodes. Therefore, one of the main barriers to developing these advanced power generation systems is the removal of particulates in a hot gas stream. Although the development of several high temperature/pressure PCD systems has been ongoing for the past several years, long term operation under realistic conditions for advanced power generation has been limited. The demonstration of reliable operation is critical to the commercialization of PCD technology for advanced power generation. The conceptual design of the Hot Gas Cleanup Test Facility Project was expanded to include additional modules to better address the scope of the Cooperative Agreement with the DOE/METC. The expanded test facility, referred to as the Power Systems Development Facility, will provide a flexible test location in which the development of advanced power system components, the evaluation of advanced turbine and fuel cell configurations, and the integration and control issues of these systems. The facility is intended to provide direct support for upcoming DOE demonstrations of power generation technologies utilizing hot stream cleanup and will provide a resource for rigorous testing and performance assessment of hot stream cleanup devices now being developed with the support of DOE/METC
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Turbine and hot gas cleanup at Wilsonville
Southern Company Services, Inc. (SCS) has entered into an agreement with the Department of Energy, Morgantown Energy Technology Center (DOE/METC) to design, construct and operate the Hot Gas Cleanup Test Facility for Gasification and Pressurized Combustion. The purpose is to identify and evaluate potential hot particulate cleanup systems on a scale large enough so that these systems can be related to potential commercial system. This entails first developing the criteria for engineering-scale testing of hot particulate control devices which will lead to the design, construction and operation of a flexible test facility capable of operating under gasification and PFBC conditions. This will allow the testing of particulate control devices (PCDs) under realistic conditions in terms of gas composition, temperature, pressure, particulate loading and operating duration. The conceptual design of the Hot Gas Cleanup Test Facility Project was expanded to include additional modules to better address the scope of the Cooperative Agreement with the DOE/METC. The expanded test facility, referred to as the Power Systems Development Facility (PSDF), will provide a flexible test location in which the development of advanced power system components, the evaluation of advanced turbine and fuel cell configurations, and the integration and control issues of these systems. The facility is intended to provide direct support for upcoming DOE demonstrations of power generation technologies utilizing hot stream cleanup and will provide a resource for rigorous testing and performance assessment of hot stream cleanup devices now being developed with the support of DOE/METC
The Atacama Cosmology Telescope: a measurement of the cosmic microwave background power spectra at 98 and 150 GHz
We present the temperature and polarization angular power spectra of the CMB measured by the Atacama Cosmology Telescope (ACT) from 5400 deg2 of the 2013â2016 survey, which covers >15000 deg2 at 98 and 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related to this, show numerous checks for systematic error done before unblinding. Using the likelihood for the cosmological analysis we constrain secondary sources of anisotropy and foreground emission, and derive a "CMB-only" spectrum that extends to â=4000. At large angular scales, foreground emission at 150 GHz is ~1% of TT and EE within our selected regions and consistent with that found by Planck. Using the same likelihood, we obtain the cosmological parameters for ÎCDM for the ACT data alone with a prior on the optical depth of Ï=0.065±0.015. ÎCDM is a good fit. The best-fit model has a reduced Ï2 of 1.07 (PTE=0.07) with H0=67.9±1.5 km/s/Mpc. We show that the lensing BB signal is consistent with ÎCDM and limit the celestial EB polarization angle to ÏP =â0.07o±0.09o. We directly cross correlate ACT with Planck and observe generally good agreement but with some discrepancies in TE. All data on which this analysis is based will be publicly released
The Atacama Cosmology Telescope: DR4 maps and cosmological parameters
We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from the Atacama Cosmology Telescope, using data taken from 2013–2016 at 98 and 150 GHz. The maps cover more than 17,000 deg2, the deepest 600 deg2 with noise levels below 10μK-arcmin. We use the power spectrum derived from almost 6,000 deg2 of these maps to constrain cosmology. The ACT data enable a measurement of the angular scale of features in both the divergence-like polarization and the temperature anisotropy, tracing both the velocity and density at last-scattering. From these one can derive the distance to the last-scattering surface and thus infer the local expansion rate, H0. By combining ACT data with large-scale information from WMAP we measure H0=67.6± 1.1 km/s/Mpc, at 68% confidence, in excellent agreement with the independently-measured Planck satellite estimate (from ACT alone we find H0=67.9± 1.5 km/s/Mpc). The ΛCDM model provides a good fit to the ACT data, and we find no evidence for deviations: both the spatial curvature, and the departure from the standard lensing signal in the spectrum, are zero to within 1σ; the number of relativistic species, the primordial Helium fraction, and the running of the spectral index are consistent with ΛCDM predictions to within 1.5–2.2σ. We compare ACT, WMAP, and Planck at the parameter level and find good consistency; we investigate how the constraints on the correlated spectral index and baryon density parameters readjust when adding CMB large-scale information that ACT does not measure. The DR4 products presented here will be publicly released on the NASA Legacy Archive for Microwave Background Data Analysis.</p
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The atacama cosmology telescope: A measurement of the cosmic microwave background power spectra at 98 and 150 GHz
We present the temperature and polarization angular power spectra of the CMB measured by the Atacama Cosmology Telescope (ACT) from 5400 deg2 of the 2013â2016 survey, which covers >15000 deg2 at 98 and 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related to this, show numerous checks for systematic error done before unblinding. Using the likelihood for the cosmological analysis we constrain secondary sources of anisotropy and foreground emission, and derive a âCMB-onlyâ spectrum that extends to ` = 4000. At large angular scales, foreground emission at 150 GHz is âŒ1% of TT and EE within our selected regions and consistent with that found by Planck. Using the same likelihood, we obtain the cosmological parameters for ÎCDM for the ACT data alone with a prior on the optical depth of Ï = 0.065 ± 0.015. ÎCDM is a good fit. The best-fit model has a reduced Ï2 of 1.07 (PTE = 0.07) with H0 = 67.9 ± 1.5 km/s/Mpc. We show that the lensing BB signal is consistent with ÎCDM and limit the celestial EB polarization angle to ÏP = â0.07⊠±0.09âŠ. We directly cross correlate ACT with Planck and observe generally good agreement but with some discrepancies in TE. All data on which this analysis is based will be publicly released
Recommended from our members
The Atacama Cosmology Telescope: DR4 maps and cosmological parameters
We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from the Atacama Cosmology Telescope, using data taken from 2013â2016 at 98 and 150 GHz. The maps cover more than 17,000 deg , the deepest 600 deg with noise levels below 10”K-arcmin. We use the power spectrum derived from almost 6,000 deg of these maps to constrain cosmology. The ACT data enable a measurement of the angular scale of features in both the divergence-like polarization and the temperature anisotropy, tracing both the velocity and density at last-scattering. From these one can derive the distance to the last-scattering surface and thus infer the local expansion rate, H . By combining ACT data with large-scale information from WMAP we measure H = 67.6±1.1 km/s/Mpc, at 68% confidence, in excellent agreement with the independently-measured Planck satellite estimate (from ACT alone we find H = 67.9 ± 1.5 km/s/Mpc). The ÎCDM model provides a good fit to the ACT data, and we find no evidence for deviations: both the spatial curvature, and the departure from the standard lensing signal in the spectrum, are zero to within 1Ï; the number of relativistic species, the primordial Helium fraction, and the running of the spectral index are consistent with ÎCDM predictions to within 1.5â2.2Ï. We compare ACT, WMAP, and Planck at the parameter level and find good consistency; we investigate how the constraints on the correlated spectral index and baryon density parameters readjust when adding CMB large-scale information that ACT does not measure. The DR4 products presented here will be publicly released on the NASA Legacy Archive for Microwave Background Data Analysis. 2 2 2 0 0
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The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters
Abstract
We present cosmological constraints from a gravitational lensing mass map covering 9400 deg2 reconstructed from measurements of the cosmic microwave background (CMB) made by the Atacama Cosmology Telescope (ACT) from 2017 to 2021. In combination with measurements of baryon acoustic oscillations and big bang nucleosynthesis, we obtain the clustering amplitude Ï
8 = 0.819 ± 0.015 at 1.8% precision,
S
8
âĄ
Ï
8
(
Ω
m
/
0.3
)
0.5
=
0.840
±
0.028
, and the Hubble constant H
0 = (68.3 ± 1.1) km sâ1 Mpcâ1 at 1.6% precision. A joint constraint with Planck CMB lensing yields Ï
8 = 0.812 ± 0.013,
S
8
âĄ
Ï
8
(
Ω
m
/
0.3
)
0.5
=
0.831
±
0.023
, and H
0 = (68.1 ± 1.0) km sâ1 Mpcâ1. These measurements agree with ÎCDM extrapolations from the CMB anisotropies measured by Planck. We revisit constraints from the KiDS, DES, and HSC galaxy surveys with a uniform set of assumptions and find that S
8 from all three are lower than that from ACT+Planck lensing by levels ranging from 1.7Ï to 2.1Ï. This motivates further measurements and comparison, not just between the CMB anisotropies and galaxy lensing but also between CMB lensing probing z ⌠0.5â5 on mostly linear scales and galaxy lensing at z ⌠0.5 on smaller scales. We combine with CMB anisotropies to constrain extensions of ÎCDM, limiting neutrino masses to âm
Μ
< 0.13 eV (95% c.l.), for example. We describe the mass map and related data products that will enable a wide array of cross-correlation science. Our results provide independent confirmation that the universe is spatially flat, conforms with general relativity, and is described remarkably well by the ÎCDM model, while paving a promising path for neutrino physics with lensing from upcoming ground-based CMB surveys.</jats:p
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The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and Its Implications for Structure Growth
Abstract
We present new measurements of cosmic microwave background (CMB) lensing over 9400 deg2 of the sky. These lensing measurements are derived from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB data set, which consists of five seasons of ACT CMB temperature and polarization observations. We determine the amplitude of the CMB lensing power spectrum at 2.3% precision (43Ï significance) using a novel pipeline that minimizes sensitivity to foregrounds and to noise properties. To ensure that our results are robust, we analyze an extensive set of null tests, consistency tests, and systematic error estimates and employ a blinded analysis framework. Our CMB lensing power spectrum measurement provides constraints on the amplitude of cosmic structure that do not depend on Planck or galaxy survey data, thus giving independent information about large-scale structure growth and potential tensions in structure measurements. The baseline spectrum is well fit by a lensing amplitude of A
lens = 1.013 ± 0.023 relative to the Planck 2018 CMB power spectra best-fit ÎCDM model and A
lens = 1.005 ± 0.023 relative to the ACT DR4 + WMAP best-fit model. From our lensing power spectrum measurement, we derive constraints on the parameter combination
S
8
CMBL
âĄ
Ï
8
Ω
m
/
0.3
0.25
of
S
8
CMBL
=
0.818
±
0.022
from ACT DR6 CMB lensing alone and
S
8
CMBL
=
0.813
±
0.018
when combining ACT DR6 and Planck NPIPE CMB lensing power spectra. These results are in excellent agreement with ÎCDM model constraints from Planck or ACT DR4 + WMAP CMB power spectrum measurements. Our lensing measurements from redshifts z ⌠0.5â5 are thus fully consistent with ÎCDM structure growth predictions based on CMB anisotropies probing primarily z ⌠1100. We find no evidence for a suppression of the amplitude of cosmic structure at low redshifts.</jats:p
The Atacama Cosmology Telescope: DR4 maps and cosmological parameters
We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from the Atacama Cosmology Telescope, using data taken from 2013â2016 at 98 and 150 GHz. The maps cover more than 17,000 deg2, the deepest 600 deg2 with noise levels below 10”K-arcmin. We use the power spectrum derived from almost 6,000 deg2 of these maps to constrain cosmology. The ACT data enable a measurement of the angular scale of features in both the divergence-like polarization and the temperature anisotropy, tracing both the velocity and density at last-scattering. From these one can derive the distance to the last-scattering surface and thus infer the local expansion rate, H0. By combining ACT data with large-scale information from WMAP we measure H0 = 67.6±1.1 km/s/Mpc, at 68% confidence, in excellent agreement with the independently-measured Planck satellite estimate (from ACT alone we find H0 = 67.9 ± 1.5 km/s/Mpc). The ÎCDM model provides a good fit to the ACT data, and we find no evidence for deviations: both the spatial curvature, and the departure from the standard lensing signal in the spectrum, are zero to within 1Ï; the number of relativistic species, the primordial Helium fraction, and the running of the spectral index are consistent with ÎCDM predictions to within 1.5â2.2Ï. We compare ACT, WMAP, and Planck at the parameter level and find good consistency; we investigate how the constraints on the correlated spectral index and baryon density parameters readjust when adding CMB large-scale information that ACT does not measure. The DR4 products presented here will be publicly released on the NASA Legacy Archive for Microwave Background Data Analysis