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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Rb2TlCl5O by Materials Project

Rb2TlOCl5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Rb is bonded in a 7-coordinate geometry to seven Cl atoms. There are a spread of Rb–Cl bond distances ranging from 3.30–3.72 Å. Tl is bonded in a 6-coordinate geometry to one O and five Cl atoms. The Tl–O bond length is 2.31 Å. There are a spread of Tl–Cl bond distances ranging from 2.54–2.86 Å. O is bonded in a distorted single-bond geometry to one Tl and one Cl atom. The O–Cl bond length is 2.39 Å. There are four inequivalent Cl sites. In the first Cl site, Cl is bonded to four equivalent Rb and one Tl atom to form a mixture of distorted edge, corner, and face-sharing ClRb4Tl square pyramids. In the second Cl site, Cl is bonded to four equivalent Rb and one Tl atom to form a mixture of distorted edge, corner, and face-sharing ClRb4Tl square pyramids. In the third Cl site, Cl is bonded in a 4-coordinate geometry to two equivalent Rb, one Tl, and one O atom. In the fourth Cl site, Cl is bonded in a 1-coordinate geometry to two equivalent Rb and one Tl atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KTlBr3 by Materials Project

KTlBr3 is High-temperature superconductor-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional and consists of eight kalium molecules and one TlBr3 framework. In the TlBr3 framework, there are two inequivalent Tl sites. In the first Tl site, Tl is bonded to six equivalent Br atoms to form corner-sharing TlBr6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–Br bond lengths are 3.07 Å. In the second Tl site, Tl is bonded to six equivalent Br atoms to form corner-sharing TlBr6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–Br bond lengths are 2.80 Å. Br is bonded in a linear geometry to two Tl atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsTlF3 by Materials Project

CsTlF3 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cs is bonded to twelve equivalent F atoms to form CsF12 cuboctahedra that share corners with twelve equivalent CsF12 cuboctahedra, faces with six equivalent CsF12 cuboctahedra, and faces with eight TlF6 octahedra. All Cs–F bond lengths are 3.46 Å. There are two inequivalent Tl sites. In the first Tl site, Tl is bonded to six equivalent F atoms to form TlF6 octahedra that share corners with six equivalent TlF6 octahedra and faces with eight equivalent CsF12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–F bond lengths are 2.67 Å. In the second Tl site, Tl is bonded to six equivalent F atoms to form TlF6 octahedra that share corners with six equivalent TlF6 octahedra and faces with eight equivalent CsF12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–F bond lengths are 2.21 Å. F is bonded in a 6-coordinate geometry to four equivalent Cs and two Tl atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs4Tl2O by Materials Project

Cs4Tl2O crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in an L-shaped geometry to two equivalent Tl and two O atoms. Both Cs–Tl bond lengths are 4.61 Å. There are one shorter (2.81 Å) and one longer (2.93 Å) Cs–O bond lengths. In the second Cs site, Cs is bonded in a single-bond geometry to five equivalent Tl and one O atom. There are a spread of Cs–Tl bond distances ranging from 4.24–4.35 Å. The Cs–O bond length is 2.86 Å. Tl is bonded in a 11-coordinate geometry to seven Cs and four equivalent Tl atoms. There are two shorter (3.27 Å) and two longer (3.29 Å) Tl–Tl bond lengths. There are two inequivalent O sites. In the first O site, O is bonded to six Cs atoms to form face-sharing OCs6 octahedra. In the second O site, O is bonded to six equivalent Cs atoms to form face-sharing OCs6 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KTlF3 by Materials Project

KTlF3 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional and consists of eight potassium molecules and one TlF3 framework. In the TlF3 framework, there are two inequivalent Tl sites. In the first Tl site, Tl is bonded to six equivalent F atoms to form corner-sharing TlF6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–F bond lengths are 2.59 Å. In the second Tl site, Tl is bonded to six equivalent F atoms to form corner-sharing TlF6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–F bond lengths are 2.20 Å. F is bonded in a linear geometry to two Tl atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlPO6 by Materials Project

TlPO6 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Tl is bonded to six O atoms to form TlO6 octahedra that share corners with four equivalent PO4 tetrahedra. There are a spread of Tl–O bond distances ranging from 2.25–2.36 Å. P is bonded to four O atoms to form PO4 tetrahedra that share corners with four equivalent TlO6 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. There are six inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Tl and one P atom. In the second O site, O is bonded in a single-bond geometry to one Tl atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Tl and one P atom. In the fourth O site, O is bonded in a single-bond geometry to one Tl atom. In the fifth O site, O is bonded in a bent 120 degrees geometry to one Tl and one P atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Tl and one P atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsTlBr3 by Materials Project

CsTlBr3 is (Cubic) Perovskite-like structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cs is bonded to twelve equivalent Br atoms to form CsBr12 cuboctahedra that share corners with twelve equivalent CsBr12 cuboctahedra, faces with six equivalent CsBr12 cuboctahedra, and faces with eight TlBr6 octahedra. All Cs–Br bond lengths are 4.20 Å. There are two inequivalent Tl sites. In the first Tl site, Tl is bonded to six equivalent Br atoms to form TlBr6 octahedra that share corners with six equivalent TlBr6 octahedra and faces with eight equivalent CsBr12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–Br bond lengths are 3.12 Å. In the second Tl site, Tl is bonded to six equivalent Br atoms to form TlBr6 octahedra that share corners with six equivalent TlBr6 octahedra and faces with eight equivalent CsBr12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Tl–Br bond lengths are 2.81 Å. Br is bonded in a distorted linear geometry to four equivalent Cs and two Tl atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlAsO6 by Materials Project

TlAsO6 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Tl is bonded to six O atoms to form TlO6 octahedra that share corners with four equivalent AsO4 tetrahedra. There are a spread of Tl–O bond distances ranging from 2.25–2.37 Å. As is bonded to four O atoms to form AsO4 tetrahedra that share corners with four equivalent TlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of As–O bond distances ranging from 1.70–1.75 Å. There are six inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Tl and one As atom. In the second O site, O is bonded in a single-bond geometry to one Tl atom. In the third O site, O is bonded in a bent 120 degrees geometry to one Tl and one As atom. In the fourth O site, O is bonded in a single-bond geometry to one Tl atom. In the fifth O site, O is bonded in a distorted bent 120 degrees geometry to one Tl and one As atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Tl and one As atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2TlHCl5 by Materials Project

Cs2TlHCl5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Cs is bonded in a 10-coordinate geometry to ten Cl atoms. There are a spread of Cs–Cl bond distances ranging from 3.60–3.94 Å. Tl is bonded in an octahedral geometry to one H and five Cl atoms. The Tl–H bond length is 1.81 Å. There are a spread of Tl–Cl bond distances ranging from 2.48–2.66 Å. H is bonded in a single-bond geometry to one Tl atom. There are four inequivalent Cl sites. In the first Cl site, Cl is bonded in a 5-coordinate geometry to four equivalent Cs and one Tl atom. In the second Cl site, Cl is bonded to four equivalent Cs and one Tl atom to form a mixture of distorted corner, edge, and face-sharing ClCs4Tl square pyramids. In the third Cl site, Cl is bonded in a distorted single-bond geometry to four equivalent Cs and one Tl atom. In the fourth Cl site, Cl is bonded to four equivalent Cs and one Tl atom to form a mixture of distorted corner, edge, and face-sharing ClCs4Tl square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2024

An innovative heterogeneous transfer learning framework to enhance the scalability of deep reinforcement learning controllers in buildings with integrated energy systems

Deep Reinforcement Learning (DRL)-based control shows enhanced performance in the management of integrated energy systems when compared with Rule-Based Controllers (RBCs), but it still lacks scalability and generalisation due to the necessity of using tailored models for the training process. Transfer Learning (TL) is a potential solution to address this limitation. However, existing TL applications in building control have been mostly tested among buildings with similar features, not addressing the need to scale up advanced control in real-world scenarios with diverse energy systems. This paper assesses the performance of an online heterogeneous TL strategy, comparing it with RBC and offline and online DRL controllers in a simulation setup using EnergyPlus and Python. The study tests the transfer in both transductive and inductive settings of a DRL policy designed to manage a chiller coupled with a Thermal Energy Storage (TES). The control policy is pre-trained on a source building and transferred to various target buildings characterised by an integrated energy system including photovoltaic and battery energy storage systems, different building envelope features, occupancy schedule and boundary conditions (e.g., weather and price signal). The TL approach incorporates model slicing, imitation learning and fine-tuning to handle diverse state spaces and reward functions between source and target buildings. Results show that the proposed methodology leads to a reduction of 10% in electricity cost and between 10% and 40% in the mean value of the daily average temperature violation rate compared to RBC and online DRL controllers. Moreover, online TL maximises self-sufficiency and self-consumption by 9% and 11% with respect to RBC. Conversely, online TL achieves worse performance compared to offline DRL in either transductive or inductive settings. However, offline Deep Reinforcement Learning (DRL) agents should be trained at least for 15 episodes to reach the same level of performance as the online TL. Therefore, the proposed online TL methodology is effective, completely model-free and it can be directly implemented in real buildings with satisfying performance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Applying Transfer Learning for Street-Scale Nuisance Flood Forecasting in Coastal-Urban Cities

An important challenge with Machine Learning (ML) is its transferability; that is, whether a ML model trained on one set of data can be applied to a second set of data without requiring a full re-training of the model. Transfer Learning (TL) addresses this challenge by transferring knowledge learned in the source domain (the data it was trained on) to the target domain (a second set of data that is statistically different but related, which the model was not trained on). This study investigates the use of TL for street-scale nuisance flood forecasting by exploring whether a ML model trained on data collected for one set of streets can effectively forecast flooding for another set of streets in the same city using TL. The envisioned use case is a city deploying a new flood depth monitoring sensor on a street and using TL to apply a ML model, trained on sensor data from an existing flood depth sensor network, to this new street. Eventually, the new flood depth sensor will have a sufficient dataset for training its own ML model, but TL can be used to fill the gap in time while this new dataset is being generated. This method is explored using a Long Short-Term Memory (LSTM) model trained on data for the flood-prone streets of Norfolk City, Virginia. The data used for training includes environmental time series (rainfall, tide), topographic features (Digital Elevation Model (DEM), Topographic Wetness Index (TWI), Depth To Water (DTW)), and street-scale flood depth time series obtained from a high-fidelity physics-based model, acting as a synthetic street-scale stream depth sensor dataset since actual stream depth sensor data is generally unavailable for most cities. A set of 180 flood-prone streets was used to train a base model, while another set of 180 flood-prone streets was used to re-train that model using different TL strategies. The results show that full-weight re-training proved most effective and minimal re-training of only the output layer was insufficient. The advantage of TL was most pronounced when target data was limited, meaning data collected at the new water depth sensor location included generally less than 18 flood events. As target data increased beyond 18 flood events, the benefit of TL diminished relative to training a ML model directly on the local flood events. These findings can assist cities as they implement street-scale flood sensing systems to create accurate forecasts for new sensing locations that do not yet have sufficient data records to train a local ML model.

Roy, Binata [Univ. of Virginia, Charlottesville, V↗
NASA NTRS1981

Laboratory study of efficient add-on treatments for interior noise control in light aircraft

Experimental and theoretical studies of the transmission loss (TL) of 1.15 x 1.46 m flat stiffened-skin aluminum panels are described. Panel configurations included panels with no treatment and eight combinations of treatments consisting of a fiberglass-septum layer, a foam-foil damping material, and a plywood double wall trim panel. Measured TL of the untreated panel and the panel with a damping layer showed characteristics of the double mass law: at low frequencies the TL followed a mass law trend associated with the average mass of both skin and stiffness, while at higher frequencies the TL followed a mass law trend associated with skin mass only. A comparison of TL for panels treated with a damping layer, a fiberglass layer, or a trim panel showed that the effects of damping are frequency dependent with some performing better below 500 Hz and others performing better above 500 Hz. Treatment combinations showed that two treatments with the same mass could have TL values different by about 10 dB, while other combinations having weights different by a factor of two could have TL values within a few dB over most of the frequency range. The highest TL values (50 dB at 1000 Hz) were obtained with a treatment consisting of a fiberglass layer, a trim panel, and damping layers on both the stiffened panel and the trim panel.

Mixson, J. S.↗
NASA NTRS1986

Thermoluminescence of Antarctic meteorites: A rapid screening technique for terrestrial age estimation, pairing studies and identification of specimens with unusual prefall histories

Thermoluminescence (TL) is a promising technique for rapid screening of the large numbers of Antarctic meteorites, permitting identification of interesting specimens that can then be studied in detail by other, more definite techniques. Specifically, TL permits determination of rough terrestrial age, identification of potential paired groups and location of specimens with unusual pre-fall histories. Meteorites with long terrestrial ages are particularly valuable for studying transport and weathering mechanisms. Pairing studies are possible because TL variations among meteorites are large compared to variations within individual objects, especially for natural TL. Available TL data for several L3 fragments, three of which were paired by other techniques, are presented as an example of the use of TL parameters in pairing studies. Additional TL measurements, specifically a blind test, are recommended to satisfactorily establish the reliability of this pairing property. The TL measurements also identify fragments with unusual pre-fall histories, such an near-Sun orbits.

Sutton, S. R.↗
NASA NTRS1991

Thermoluminescence survey of 12 meteorites collected by the European 1988 Antarctic meteorite expedition to Allan Hills and the importance of acid washing for thermoluminescence sensitivity measurements

Natural and induced thermoluminescence (TL) data are reported for 12 meteorites recovered from the Allan Hills region of Antarctica by the European field party during the 1988/1989 field season. The samples include one with extremely high natural TL, ALH88035, suggestive of exposure to unusually high radiation doses (i.e., low degrees of shielding), and one, ALH88034, whose low natural TL suggests reheating within the last 100,000 years. The remainder have natural TL values suggestive of terrestrial ages similar to those of other meteorites from Allan Hills. ALH88015 (L6) has induced TL data suggestive of intense shock. TL sensitivities of these meteorites are generally lower than observed falls of their petrologic types, as is also observed for Antarctic meteorites in general. Acid-washing experiments indicate that this is solely the result of terrestrial weathering rather than a nonterrestrial Antarctic-non-Antarctic difference. However, other TL parameters, such as natural TL and induced peak temperature-width, are unchanged by acid washing and are sensitive indicators of a meteorite's metamorphic and recent radiation history.

Benoit, P. H.↗
NASA NTRS1999

The Natural Thermoluminescence Survey of Antarctic Meteorites: Ordinary Chondrites at the Grosvenor Mountains, Macalpine Hills, Pecora Escarpment and Queen Alexandra Range, and New Data for the Elephant Moraine, Ice Fields

The natural TL (Thermoluminescence) survey of Antarctic meteorites was started in 1987 at the request of the Antarctic Meteorite Working Group in order to provide an initial description of radiation and thermal histories. It was intended to be a complement to the mineralogical and petrographic surveys performed at the Johnson Space Center and the Smithsonian Institution. All ANSMET (Antarctic Search for Meteorites) samples recovered since then, besides those that were heated throughout by atmospheric passage, have been measured. To date this amounts to about 1200 samples. As the data for each ice field reaches a significant level, we have been conducting a thorough examination of the data for that field with a view to identifying pairing, providing an estimate of terrestrial age and residence time on the ice surface, looking for differences in natural TL between ice fields, looking for variations in natural TL level with location on the ice, looking for meteorites with natural TL levels outside the normal range. Pairing is a necessary first step in ensuring the most productive use of the collection, while geographical variations could perhaps provide clues to concentration mechanisms. Samples with natural TL values outside the normal range are usually inferred to have had either small perihelia or recent changes in orbital elements. In addition, induced TL data have enabled us to look for evidence for secular variation in the nature of the flux of meteorites to Earth, and look for petrologically unusual meteorites, such as particularly primitive ordinary chondrites, heavily shocked meteorites, or otherwise anomalous meteorites. To date we have published studies of the TL properties of 167 ordinary chondrites from Allan Hills, 107 from Elephant Moraine and 302 from Lewis Cliff and we have discussed the TL properties of fifteen H chondrites collected at the Allan Hills by Euromet after a storm during the 1988 season. We now have additional databases for a reasonable number of ordinary chondrites from Grosvenor Mountains (39 meteorites), MacAlpine Hills (70 meteorites), Pecora Escarpment (60 meteorites), and Queen Alexandra Range (173 meteorites) and we have data for a further 101 samples from Elephant Moraine. The results are summarized. We also have fairly minimal databases (10-15 meteorites) for Dominion Range, Graves Nunataks, Reckling Peak and Wisconsin Range that will not be discussed here.

Benoit, Paul H.↗
NASA NTRS2000

The Natural Thermoluminescence Survey of Antarctic Meteorites: Ordinary Chondrites at the Grosvenor Mountains, MacAlpine Hills, Pecora Escarpment and Queen Alexandra Range, and New Data New Data for the Elephant Moraine, Ice Fields

The natural TL survey of Antarctic meteorites was started in 1987 at the request of the Antarctic Meteorite Working Group in order to provide an initial description of radiation and thermal histories. It was intended to be a complement to the mineralogical and petrographic surveys performed at the Johnson Space Center and the Smithsonian Institution. All ANSMET samples recovered since then, besides those that were heated throughout by atmospheric passage, have been measured. To date this amounts to about 1200 samples. As the data for each ice field reaches a significant level, we have been conducting a thorough examination of the data for that field with a view to (1) identifying pairing, (2) providing an estimate of terrestrial age and residence time on the ice surface, (3) looking for differences in natural TL between ice fields, (4) looking for variations in natural TL level with location on the ice, (5) looking for meteorites with natural TL levels outside the normal range. Pairing is a necessary first step in ensuring the @ost productive use of the collection, while geographical variations could perhaps provide clues to concentration mechanisms. Samples with natural TL values outside the normal range are usually inferred to have had either small perihelia or recent changes in orbital elements. In addition, induced TL data have enabled us to (5) look for evidence for secular variation in the nature of the flux of meteorites to Earth, and (6) look for petrologically unusual meteorites, such as particularly primitive ordinary chondrites, heavily shocked meteorites, or otherwise anomalous meteorites. To date we have published studies of the TL properties of 167 ordinary chondrites from Allan Hills, 107 from Elephant Moraine and 302 from Lewis Cliff and we have discussed the TL properties of fifteen H chondrites collected at the Allan Hills by Euromet after a storm during the 1988 season. We now have additional databases for a reasonable number of ordinary chondrites from Grosvenor Mountains (39 meteorites), MacAlpine Hills (70 meteorites), Pecora Escarpment (60 meteorites), and Queen Alexandra Range (173 meteorites) and we have data for a further 101 samples from Elephant Moraine. The results are summarized in Table 1. We also have fairly minimal databases (10-15 meteorites) for Dominion Range, Graves Nunataks, Reckling Peak and Wisconsin Range that will not be discussed here.

Benoit, Paul H.↗
DOE OSTI2020

Materials Data on DyTlPd by Materials Project

DyPdTl crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Dy is bonded in a 11-coordinate geometry to five Pd and six equivalent Tl atoms. There are four shorter (3.06 Å) and one longer (3.16 Å) Dy–Pd bond lengths. There are two shorter (3.22 Å) and four longer (3.37 Å) Dy–Tl bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent Dy and six equivalent Tl atoms. All Pd–Tl bond lengths are 2.84 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent Dy and three equivalent Tl atoms. All Pd–Tl bond lengths are 2.92 Å. Tl is bonded in a 10-coordinate geometry to six equivalent Dy and four Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YTlPd by Materials Project

YPdTl crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Y is bonded in a 11-coordinate geometry to five Pd and six equivalent Tl atoms. There are four shorter (3.07 Å) and one longer (3.17 Å) Y–Pd bond lengths. There are two shorter (3.23 Å) and four longer (3.38 Å) Y–Tl bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent Y and three equivalent Tl atoms. All Pd–Tl bond lengths are 2.92 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent Y and six equivalent Tl atoms. All Pd–Tl bond lengths are 2.84 Å. Tl is bonded in a 10-coordinate geometry to six equivalent Y and four Pd atoms.

36 MATERIALS SCIENCE↗