Ignition of metals with ClF sub 3 and ClF sub 5 for use as spacecraft chemical heaters
Chemical heat source combined with metals ignition properties considered for spacecraft heating during Mars nighttime landing
Rhein, R. A.↗
SEARCH · Engineering Papers
Results for “ClF”
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AmeriFlux FLUXNET-1F US-CLF Cole Farm
This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-CLF Cole Farm. This is the FLUXNET version of the carbon flux data for the site US-CLF Cole Farm produced by applying the standard ONEFlux (1F) software. Site Description - The Cole Farm catchment (0.65km2) is located ~ 4 km southwest of the Shale Hills site, draining orthogonally to a syncline axis of the Wills Creek Formation, a calcareous shale containing interbedded siltstone, sandstone, shaly limestone, and dolomite. Even though the farm adopted no-till practices in the 1970s, the axial channel of Cole Farm flows over a thick (>2.5 m) package of sediment in the valley floor. Soils range in texture from silty clay at the ridge top to sandy loam in the valley floor. Data was collected and funded by the Critical Zone Observatory Network.
Davis, Kenneth J. [Department of Meteorology, Eart↗
Materials Data on ClF by Materials Project
ClF is alpha carbon monoxide-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four chlorine fluoride molecules. Cl is bonded in a single-bond geometry to one F atom. The Cl–F bond length is 1.69 Å. F is bonded in a single-bond geometry to one Cl atom.
36 MATERIALS SCIENCE↗
Materials Data on K2Cu(ClF)2 by Materials Project
K2Cu(ClF)2 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to five equivalent Cl1- and four equivalent F1- atoms. There are four shorter (3.21 Å) and one longer (3.29 Å) K–Cl bond lengths. All K–F bond lengths are 2.92 Å. Cu2+ is bonded to two equivalent Cl1- and four equivalent F1- atoms to form corner-sharing CuCl2F4 octahedra. The corner-sharing octahedral tilt angles are 0°. Both Cu–Cl bond lengths are 2.33 Å. There are two shorter (1.92 Å) and two longer (2.56 Å) Cu–F bond lengths. Cl1- is bonded in a 6-coordinate geometry to five equivalent K1+ and one Cu2+ atom. F1- is bonded in a 1-coordinate geometry to four equivalent K1+ and two equivalent Cu2+ atoms.
36 MATERIALS SCIENCE↗
Materials Data on Ba3Sr(ClF)4 by Materials Project
Ba3Sr(ClF)4 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are one shorter (3.27 Å) and four longer (3.30 Å) Ba–Cl bond lengths. All Ba–F bond lengths are 2.68 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are one shorter (3.22 Å) and four longer (3.31 Å) Ba–Cl bond lengths. All Ba–F bond lengths are 2.68 Å. In the third Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are one shorter (3.24 Å) and four longer (3.29 Å) Ba–Cl bond lengths. All Ba–F bond lengths are 2.68 Å. Sr2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are one shorter (3.13 Å) and four longer (3.28 Å) Sr–Cl bond lengths. All Sr–F bond lengths are 2.57 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four equivalent Ba2+ and one Sr2+ atom. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Ba2+ atoms. In the third Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Ba2+, four equivalent Sr2+, and four equivalent F1- atoms. All Cl–F bond lengths are 3.25 Å. In the fourth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Ba2+ atoms. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to four Ba2+ atoms to form a mixture of edge and corner-sharing FBa4 tetrahedra. In the second F1- site, F1- is bonded to two equivalent Ba2+, two equivalent Sr2+, and two equivalent Cl1- atoms to form a mixture of edge, face, and corner-sharing FBa2Sr2Cl2 tetrahedra.
36 MATERIALS SCIENCE↗
Materials Data on Sr3Ca(ClF)4 by Materials Project
Sr3Ca(ClF)4 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are four shorter (3.13 Å) and one longer (3.19 Å) Sr–Cl bond lengths. All Sr–F bond lengths are 2.51 Å. In the second Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are one shorter (3.09 Å) and four longer (3.12 Å) Sr–Cl bond lengths. All Sr–F bond lengths are 2.53 Å. In the third Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are four shorter (3.11 Å) and one longer (3.13 Å) Sr–Cl bond lengths. All Sr–F bond lengths are 2.51 Å. Ca2+ is bonded in a 9-coordinate geometry to five Cl1- and four equivalent F1- atoms. There are one shorter (3.05 Å) and four longer (3.10 Å) Ca–Cl bond lengths. All Ca–F bond lengths are 2.41 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four equivalent Sr2+ and one Ca2+ atom. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Sr2+ atoms. In the third Cl1- site, Cl1- is bonded in a 5-coordinate geometry to one Sr2+, four equivalent Ca2+, and four equivalent F1- atoms. All Cl–F bond lengths are 3.12 Å. In the fourth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Sr2+ atoms. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to four Sr2+ atoms to form a mixture of edge and corner-sharing FSr4 tetrahedra. In the second F1- site, F1- is bonded to two equivalent Sr2+, two equivalent Ca2+, and two equivalent Cl1- atoms to form a mixture of edge, face, and corner-sharing FSr2Ca2Cl2 tetrahedra.
36 MATERIALS SCIENCE↗
AmeriFlux US-CLF Cole Farm
This is the AmeriFlux version of the carbon flux data for the site US-CLF Cole Farm. Site Description - The Cole Farm catchment (0.65km2) is located ~ 4 km southwest of the Shale Hills site, draining orthogonally to a syncline axis of the Wills Creek Formation, a calcareous shale containing interbedded siltstone, sandstone, shaly limestone, and dolomite. Even though the farm adopted no-till practices in the 1970s, the axial channel of Cole Farm flows over a thick (>2.5 m) package of sediment in the valley floor. Soils range in texture from silty clay at the ridge top to sandy loam in the valley floor. Data was collected and funded by the Critical Zone Observatory Network.
Davis, Kenneth J.↗
Materials Data on C(ClF)2 by Materials Project
CCl2F2 is gamma plutonium structured and crystallizes in the orthorhombic Fdd2 space group. The structure is zero-dimensional and consists of eight dichlorodifluoromethane molecules. C4+ is bonded in a tetrahedral geometry to two equivalent Cl1- and two equivalent F1- atoms. Both C–Cl bond lengths are 1.76 Å. Both C–F bond lengths are 1.36 Å. Cl1- is bonded in a single-bond geometry to one C4+ atom. F1- is bonded in a single-bond geometry to one C4+ atom.
36 MATERIALS SCIENCE↗
Materials Data on SiC(ClF)3 by Materials Project
CCl3SiF3 is Ammonia-derived structured and crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of four fluoroform molecules and four trichlorosilane molecules.
36 MATERIALS SCIENCE↗
Galaxy Populations in Groups and Clusters: Evidence for a Characteristic Stellar Mass Scale at M * ~ 10 9.5 M ⊙
We use the DR9 of the DESI legacy imaging survey and SDSS galaxy groups to measure the conditional luminosity function (CLF) for groups with halo mass Mh ≥ 10 12 M ⊙ and redshift 0.01 ≤ z ≤ 0.08, down to a limiting r-band magnitude of M r = –10 to –12. For given halo masses we measure the CLF for the total populations and for the red and blue populations classified using the (g – z) color. We find a clear faint-end upturn in the CLF of red satellites, with a slope α ≈ –1.8, which is almost independent of halo mass. This faint-end upturn is not seen for the blue and total populations. Our stellar population synthesis modeling shows that (g – z) provides a clean red/blue division and that red group galaxies defined by (g – z) are all dominated by old stellar populations. The fraction of old galaxies as a function of galaxy luminosity shows a minimum at M r ~ –18, corresponding to M * ~ 10 9.5 M ⊙ . This scale is independent of halo mass and is comparable to the characteristic luminosity at which galaxies show a dichotomy in surface brightness and size, suggesting that the dichotomy in the old fraction and in galaxy structure may have a common origin. The rising of the old fraction at the faint end for Milky Way (MW)–sized halos is in good agreement with the quenched fraction measured for the MW/M31 system and from the ELVES survey. We discuss the implications of our results for the formation and evolution of low-mass galaxies and for the stellar mass functions of low-mass galaxies to be observed at high redshift.
79 ASTRONOMY AND ASTROPHYSICS↗
Low cost monocrystalline silicon sheet fabrication for solar cells by advanced ingot technology
The continuous liquid feed (CLF) Czochralski furnace and the enhanced I.D. slicing technology for the low-cost production of monocrystalline silicon sheets for solar cells are discussed. The incorporation of the CLF system is shown to improve ingot production rate significantly. As demonstrated in actual runs, higher than average solidification rates (75 to 100 mm/hr for 150 mm 1-0-0 crystals) can be achieved, when the system approaches steady-state conditions. The design characteristics of the CLF furnace are detailed, noting that it is capable of precise control of dopant impurity incorporation in the axial direction of the crystal. The crystal add-on cost is computed to be $11.88/sq m, considering a projected 1986 25-slice per cm conversion factor with an 86% crystal growth yield.
Fiegl, G. F.↗
Data-driven modeling and control of dynamical systems using Koopman and Perron-Frobenius operators
This dissertation studies the data-driven modeling and control problem of nonlinear systems by exploiting the linear operator theoretic framework involving Koopman and Perro-Frobenius operator. A systematic linear-operator based controller design procedure has been established, which can be used to solve a variety of nonlinear control problems, including feedback stabilization using control Lyapunov functions, optimal quadratic regulation using Koopman eigenfunctions and convex optimization formulation of optimal control problem using P-F and Koopman operator approximation. As the core of data-driven modeling, we first propose a new algorithm for the finite-dimensional approximation of the linear transfer Koopman and Perron-Frobenius operator from time-series data. We argue that the existing approach for the finite-dimensional approximation of these transfer operators such as Dynamic Mode Decomposition (DMD) and Extended Dynamic Mode Decomposition (EDMD) do not capture two important properties of these operators, namely positivity and Markov property. The algorithm we propose preserves these two properties. We call the proposed algorithm as naturally structured DMD (NSDMD) since it retains the inherent properties of these operators. Naturally structured DMD algorithm leads to a better approximation of the steady-state dynamics of the system regarding computing Koopman and Perron- Frobenius operator eigenfunctions and eigenvalues. However, preserving positivity property is critical for capturing the real transient dynamics of the system. This positivity property of the transfer operators and it's finite-dimensional approximation play an important role for controller and estimator design of nonlinear systems. To solve the feedback stabilization problem for nonlinear control systems, we tried to take advantage of the Koopman operator framework. The Koopman operator approach provides a linear representation for a nonlinear dynamical system and a bilinear representation for a nonlinear control system. The problem of feedback stabilization of a nonlinear control system is then transformed to the stabilization of a bilinear control system. We propose a control Lyapunov function (CLF)-based approach for the design of stabilizing feedback controllers for the bilinear system. The search for finding a CLF for the bilinear control system is formulated as a convex optimization problem. This leads to a schematic procedure for designing CLF-based stabilizing feedback controllers for the bilinear system and hence the original nonlinear system. Another advantage of the proposed controller design approach outlined in this dissertation is that it does not require explicit knowledge of system dynamics. In particular, the bilinear representation of a nonlinear control system in the Koopman eigenfunction space can be obtained from time-series data. Next, we study the optimal quadratic regulation problem for nonlinear systems. The linear operator theoretic framework involving the Koopman operator is used to lift the dynamics of nonlinear control system to an infinite-dimensional bilinear system. The optimal quadratic regulation problem for nonlinear system is formulated in terms of the finite-dimensional approximation of the bilinear system. A convex optimization-based approach is proposed for solving the quadratic regulator problem for bilinear system. We applied a variety of examples and compared the simulation results between our framework and conventional LQR control using linearized model. For more general optimal control problems, we provide a density-function based convex formulation for the optimal control problem of the nonlinear system. The convex formulation relies on the duality result in the stability theory of a dynamical system involving density function and Perron-Frobenius operator. The optimal control problem is formulated as an infinite-dimensional convex optimization program. The finite-dimensional approximation of the optimization problem relies on the recent advances made in the data-driven computation of the Koopman operator, which is dual to the Perron-Frobenius operator. Simulation results are presented to demonstrate the application of the developed framework.
Huang, Bowen↗
Elevated Forest Canopy Loss After Wildfires in Moist and Cool Forests in the Pacific Northwest
Wildfire frequency, intensity, and rate of spread are increasing across the Western U.S, resulting in more severe ecosystem impacts. Significant tree mortality can occur years after fire events, but this has received little attention compared to the immediate tree loss during a fire. We overlapped forest cover loss data with burn severity maps in the U.S. Pacific Northwest and quantified the total and delayed forest canopy loss after fires. We found that wildfires resulted in total canopy loss fraction (CLF) of 84%, 53%, and 22% within 3 years in areas burned at high, moderate, and low severity, respectively. The delayed canopy loss accounted for approximately 1/3, 1/2, and 2/3 of the total canopy loss for high, moderate, and low severity burns. Delayed canopy loss was greater in moist and cool areas than in dry and warm areas, likely because tree species in wetter environments were less adapted to survive when fires did occur. Across all forests, delayed CLF doubled as temperature increased from the climatological mean to a hot anomaly and tripled as vapor pressure deficit increased from a wet anomaly to a dry anomaly. Fire impacts on forest ecosystems are likely to intensify under future climate scenarios as wildfires expand into areas that historically experienced infrequent fires. The impacts can also be exacerbated by more frequent compound extreme events, such as droughts, heatwaves, and fires. These findings highlight the urgent need for targeted forest management strategies, particularly in mesic forests, to mitigate future fire impacts.
54 ENVIRONMENTAL SCIENCES↗
Spectroscopy of Chlorosyl Fluoride, FClO
FClO has been proposed as an intermediate in reactions involving ClF, Cl2O, and ClF3O, and it has been suggested as a molecule of atmospheric interest. It has been prepared in situ by the hydrolysis of ClF3. The pure rotational spectrum of FClO has been studied by conventional millimeter wave techniques and by microwave Fourier transform spectroscopy. Selected transitions were searched for using predictions based on an analysis of the nu(sub 1) band. FClO is an asymmetric prolate top, kappa = -0.8950 for F(35)ClO, with a rather small dipole component of 0.093 (4) D along the a-axis and a larger one of 1.93 (5) D along the b-axis. Transitions with 0 <= J <= 54 and 0 <= K(sub a) <= 18 were observed. Cl hyperfine splitting was generally observable throughout the spectrum with F-19 spin-rotation splitting observable as well in the microwave region. Structural parameters, harmonic force constants, and nuclear magnetic shielding parameters were derived and will be compared with data of related molecules, such as ClF3, ClF, FClO2, and FClO3. High resolution infrared spectra were taken in the regions of the FCl stretching mode and bending mode around 600 and 310/cm, respectively. A preliminary analysis indicates that the FCl stretch, near 596.86/cm for F(35)ClO, is in resonance with the dark overtone of delta near 617/cm. A brief progress report will be given.
Mueller, Holger S. P.↗
The oxygen stable isotope composition of CRM 125-A UO 2 standard reference material
While there is a clear need for standardized reference materials for analytical calibrations and for inter-laboratory comparisons, there are not currently any for the oxygen stable isotopic composition of uranium oxides. In this paper we summarize the results from four laboratories by seven different methods of oxygen stable isotope analyses using fluorination techniques of CRM 125-A UO 2 Standard Reference Material. We synthesize these data and methods to arrive at a consensus oxygen stable isotope composition for CRM 125-A $δ$ 18 O = -9.63‰ (±0.29‰) VSMOW. We discuss methodological differences between analytical approaches, including furnace vs laser heating, fluorination using BrF 5 or ClF 3 , as well as calibration strategies. We highlight the potential effects of calibration scale compression from single-point calibrations using reference material with $δ$ 18 O values having a large relative difference from the sample being analyzed. We demonstrate how calibration scale compression can yield differences in calibrated $δ$ 18 O values up to ~2‰ for samples with ~20‰ difference from a single reference material, if the calibration slope of different analytical systems differs by 0.1. In conclusion, we suggest the use of liquid water calibration standards sealed in silver capillary tubes for multi-point calibrations of fluorination analysis systems.
07 ISOTOPE AND RADIATION SOURCES↗
Measuring the Conditional Luminosity and Stellar Mass Functions of Galaxies by Combining the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys Data Release 9, Survey Validation 3, and Year 1 Data
In this investigation, we leverage the combination of the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys Data Release 9, Survey Validation 3, and Year 1 data sets to estimate the conditional luminosity functions and conditional stellar mass functions (CLFs and CSMFs) of galaxies across various halo mass bins and redshift ranges. To support our analysis, we utilize a realistic DESI mock galaxy redshift survey (MGRS) generated from a high-resolution Jiutian simulation. An extended halo-based group finder is applied to both MGRS catalogs and DESI observation. By comparing the r- and z-band luminosity functions (LFs) and stellar mass functions (SMFs) derived using both photometric and spectroscopic data, we quantified the impact of photometric redshift (photo-z) errors on the galaxy LFs and SMFs, especially in the low-redshift bin at the low-luminosity/mass end. By conducting prior evaluations of the group finder using MGRS, we successfully obtain a set of CLF and CSMF measurements from observational data. We find that at low redshift, the faint-end slopes of CLFs and CSMFs below ~10 9 h –2 L ⊙ (or h –2 M ⊙ ) evince a compelling concordance with the subhalo mass functions. After correcting the cosmic variance effect of our local Universe following Chen et al., the faint-end slopes of the LFs/SMFs turn out to also be in good agreement with the slope of the halo mass function.
79 ASTRONOMY AND ASTROPHYSICS↗
The Solar System Beyond Neptune
The aim of this research is to study the objects in the Kuiper Belt, in order to understand the nature of its origin and the evolutionary processes which have affected the Kuiper Belt. Particular science objectives include: 1) the determination of the sky-plane surface density of Kuiper Belt Objects (KBOs); 2) the determination of the slope of the cumulative luminosity function (CLF); 3) the determination of the KBO size distribution; 4) the isolation of bright KBOs from which physical measurements can be secured using existing 10-meter diameter class telescopes; 5) physical measurements of bright KBOs designed to assess their composition. Major results obtained under the grant include: 1) The determination of the surface density of KBOs (objects per square degree of sky) as a function of apparent red magnitude in the range 21 less than MR less than 24.8. 2) The discovery of a new dynamical class in the Kuiper Belt, exemplified by 1996 TL66. 3) Physical observations of two bright KBOs were secured using the Keck 10-meter telescope and an infrared imager/spectrometer; 4) In support of public interest in the Kuiper Belt, we wrote a popular article for Scientific American magazine and we developed a "Kuiper Belt Home Page" on the world-wide web.
Jewitt, David↗
X-ray thermal diffuse scattering as a texture-robust temperature diagnostic for dynamically compressed solids
We present a model of x-ray thermal diffuse scattering (TDS) from a cubic polycrystal with an arbitrary crystallographic texture, based on the classic approach of Warren [B. E. Warren, Acta Crystallogr. 6, 803 (1953)]. We compare the predictions of our model with femtosecond x-ray diffraction patterns gathered from ambient and dynamically compressed rolled copper foils obtained at the High Energy Density instrument of the European X-Ray Free-Electron Laser facility and find that the texture-aware TDS model yields more accurate results than does the conventional powder model owed to Warren. Nevertheless, we further show: with sufficient angular detector coverage, the TDS signal is largely unchanged by sample orientation and in all cases strongly resembles the signal from a perfectly random powder; shot-to-shot fluctuations in the TDS signal resulting from grain-sampling statistics are at the percent level, in stark contrast to the fluctuations in the Bragg-peak intensities (which are over an order of magnitude greater); and TDS is largely unchanged even following texture evolution caused by compression-induced plastic deformation. We conclude that TDS is robust against texture variation, making it a flexible temperature diagnostic applicable just as well to off-the-shelf commercial foils as to ideal powders.
Crystal lattices↗