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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

169 Tm(n,2n) 168 Tm and 169 Tm(n,3n) 167 Tm cross-section measurements from 15 to 21 MeV

The 169 Tm(n,2n) 168 Tm and 169 Tm(n,3n) 167 Tm cross sections have been measured in the neutron energy range between 15 and 21 MeV using the 3 H(d,n) 4 He neutron source reaction. The 169 Tm(n,3n) 167 Tm data are intended to provide an accurate database for interpreting so-called reaction-in-flight neutron yields, which provide a sensitive tool for studying properties of the deuterium-tritium plasma created in inertial confinement fusion laser shots at the National Ignition Facility at Lawrence Livermore National Laboratory. The data are compared to previous data and evaluations for the reaction studied and are found to be in good agreement with the ENDF/B-VIII.0 evaluation, although small adjustments are necessary for the 169 Tm(n,3n) 167 Tm reaction. Here, for the first time in any (n,2n) cross-section measurements to date, a comprehensive data set ranging from threshold to 21 MeV has been obtained by the same group.

150 ≤ A ≤ 189↗
NASA NTRS1987

Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies. LANDSAT TM investigation proposal TM-019

Processing and interpretation of Thematic Mapper (TM) data, extensive field work, and processing of SPOT data were continued. Results of these analyses led to the testing and rejecting of several of the geologic/tectonic hypotheses concerning the continuation of the Garlock Fault Zone (GFZ). It was determined that the Death Valley Fault Zone (DVFZ) is the major through-going feature, extending at least 60 km SW of the Avawatz Mountains. Two 5 km wide fault zones were identified and characterized in the Soda and Bristol Mountains, forming a continuous zone of NW trending faulting. Geophysical measurements indicate a buried connection between the Avawatz and the Soda Mountains Fault Zone. Future work will involve continued field work and mapping at key locations, further analyses of TM data, and conclusion of the project.

Abrams, Michael↗
NASA NTRS1991

Investigation of loss processes of Tm and Tm,Ho in YAG

The loss of excitation from various manifolds of Tm and Tm,Ho in YAG as a function of temperature and concentration is studied. Two probable loss mechanisms - a Tm up-conversion and a Ho up-conversion - are identified. A 785-nm CW diode laser with 400-nW peak power was focused to a small spot on the sample. The emission from the sample observed at 90 deg was monitored through a monochromator with slits open to 3 mm. Intensity of emission was measured by varying the power of the excitation source using a set of neutral density filters. Power is reported as the percentage of the peak power, and the intensity curves were normalized below 20 percent of transmission. The fact that there is emission above the pump energy indicates an up-conversion from excited manifolds. Nonlinear changes in the intensity of the emission from the Tm 3F4 manifold with the pump power reveals a loss of excitation from this manifold. The linear dependence of the 5I7 manifold emission with pump power at low Tm and high Ho concentrations and the gain of energy in the 5I6 manifold of Ho indicate that the 5I7 manifold loss is due to the coupling of Tm and Ho ions.

Armagan, G.↗
NASA NTRS1991

Modeling Cr-to-Tm and Cr-to-Tm-to-Ho energy transfer in YAG crystals

A systematic analysis of energy transfer processes in crystals of YAG doped with varying concentrations of Cr and Tm is described. Both spectral measurements and measurements of the temporal response to pulsed excitation are used to give independent determinations of the microscopic interaction parameter for Cr to Tm transfer. The different factors in influencing the temperature dependence of the Cr to Tm transfer are discussed. The dependence of the Tm cross-relaxation rate on Tm concentration is determined.

Swetits, John J.↗
NASA NTRS2004

Results of a Telephone Survey of Television Station Managers Concerning the NASA SCI Files(TM) and NASA CONNECT(TM)

A telephone survey of television station managers concerning 2 instructional television programs, the NASA SCI Files(TM) and NASA CONNECT(TM), offered by the NASA Langley Center for Distance Learning (CDL) was conducted. Using a 4-point scale, with 4 being very satisfied, survey participants reported that they were either very satisfied (77.1 percent) or satisfied (19.9 percent) with the overall (educational and technical) quality of the NASA SCI Files(TM). Using a 4-point scale, with 4 being very satisfied, survey participants reported that they were either very satisfied (77.9 percent) or satisfied (19.1 percent) with the overall (educational and technical) quality of NASA CONNECT(TM) .

Pinelli, Thomas E.↗
DOE OSTI2020

Measuring aerosol collection efficiency for the Bladewerx “New Speclon TM 5” and the older “Speclon TM 5” filter

Bladewerx TM LLC (Rio Rancho, NM) manufactures instrumentation, neutron shielding and activation foils for the radiation protection industry. Specializing in portable alpha/beta air monitors and sample counters, Bladewerx is the source of Speclon TM PTFE filter media that they recommend for high-resolution alpha spectroscopy. Los Alamos National Laboratory (LANL) utilizes Speclon TM filter material in CAM (Continuous Air Monitor) samplers for workplace air monitoring. The LANL Aerosol Engineering Facility received air filter material from Bladewerx, referred to as “New Speclon 5” in this document, in order to distinguish from filter material that was previously received (referred to as “Speclon 5” in this document). In this document, the aerosol collection efficiency and airflow resistance (pressure drop) were measured for the New Speclon 5 filter material.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2024

The Significance of the 'Insignificant': Non-covalent Interactions in CO 2 Reduction Reactions with 3C-TM (TM=Sc-Zn) Single-Atom Catalysts

With energy shortages and excessive CO 2 emissions driving climate change, converting CO 2 into high-value-added products offers a promising solution for carbon recycling. We investigate CO 2 reduction reactions (CO2RR) catalyzed by 10 single-atom catalysts (SACs), incorporating weak non-covalent interactions, specifically lone pair-π and H-π interactions. The SACs, consisting of transition metals coordinated by three carbon atoms in a defective graphene substrate (3C-TM, TM=Sc-Zn), leverage these interactions to influence the energy fluctuations of intermediates and the limiting potentials of CO 2 RR, without altering the overall reaction pathway. Further, our findings show that SACs based on early transition metals (Sc, Ti, V, Cr) can serve as catalysts for C 1 products, including HCOOH, HCHO, CH 3 OH, and CH 4 , while those based on Fe and Co are suitable for CO formation. Driving force analysis helps bridge theoretical results with experimental observations and propose a modified approach for assessing hydrogen evolution reactions (HER) competition. SACs based on Ni and Cu exhibit moderate HER tolerance, while early transition metals excel in selective CO 2 reduction. We also identify a linear scaling relationship between the free energies of *COOH and *CO. This study offers valuable insights for future experimental studies and large-scale computational screenings.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1976

An assembler for the MOS Technology 6502 microprocessor as implemented in jolt (TM) and KIM-1 (TM)

Design of low-cost, microcomputer-based navigation receivers, and the assembler are described. The development of computer software for microprocessors is materially aided by the assembler program using mnemonic variable names. The flexibility of the environment provided by the IBM's Virtual Machine Facility and the Conversational Monitor System, make possible the convenient assembler access. The implementation of the assembler for the microprocessor chip serves a part of the present need and forms a model for support of other microprocessors.

Lilley, R. W.↗
NASA NTRS1993

VPU(tm) demonstration mission vicinity processor unit(tm) overview

Evolving Technologies Corporation is designing a new type of computer called a Vicinity Processor Unit (VPU). The VPU is designed to monitor and control payloads using an operating system, control process and software environment that specifically takes into account the time delay associated with remotely controlling and monitoring a group of payloads in real time. This is a fundamentally different way of computing which has vast scientific implications for the design and implementation of data processing systems for future space flight missions. As a demonstration mission, the VPU is expected to be flown aboard the Space Shuttle (Payload Identification No. G-700) as a part of NASA's Small Self-Contained Payloads (SSCP) Program. We believe this mission can greatly facilitate the development and validation of technology which may prove to be mission critical for many future space flight missions.

Abdulezer, Loren↗
DOE OSTI2020

Materials Data on Tm by Materials Project

Tm is alpha Samarium structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are four inequivalent Tm sites. In the first Tm site, Tm is bonded to twelve Tm atoms to form a mixture of edge, corner, and face-sharing TmTm12 cuboctahedra. There are six shorter (3.47 Å) and six longer (3.51 Å) Tm–Tm bond lengths. In the second Tm site, Tm is bonded to twelve Tm atoms to form a mixture of edge, corner, and face-sharing TmTm12 cuboctahedra. There are three shorter (3.45 Å) and six longer (3.51 Å) Tm–Tm bond lengths. In the third Tm site, Tm is bonded to twelve Tm atoms to form a mixture of edge, corner, and face-sharing TmTm12 cuboctahedra. All Tm–Tm bond lengths are 3.51 Å. In the fourth Tm site, Tm is bonded to twelve Tm atoms to form a mixture of edge, corner, and face-sharing TmTm12 cuboctahedra. There are a spread of Tm–Tm bond distances ranging from 3.45–3.51 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2025

In-Situ FTIR Detection of Transition Metal (TM)-Ion Dissolution From Cathodes in Li-Ion Batteries

Transition metal (TM) ions, commonly Ni and Mn, play a crucial role in Li-ion battery cathodes as the reaction centers for rapid redox reactions. A major challenge with TM-based cathodes is capacity degradation, particularly at higher operating voltages. This degradation is closely linked to the dissolution of TMs from the cathode materials and their subsequent deposition on the anode. This process not only modifies the surface structure of the cathode but, more significantly, alters the SEI composition on the anode [1-2]. The dissolution of TMs cations into a liquid electrolyte from cathode materials, such as Mn-ion dissolution from Mn-rich cathode (LMR), is detrimental to the cycling performance of Li-ion batteries [3-4]. Much attention has been paid to this issue but there remains a lack of characterization techniques which can detect the TM-ion dissolution from the cathode during electrochemical measurements. In our study, we use in-situ ATR-FTIR as an effective technique to probe the TM-ion dissolution from the cathode. We have first demonstrated the detrimental effects of TM ions on the electrochemical performance of Li-ion batteries by adding a small amount of TM salt (50 mM Mn(PF6)) to the electrolyte of a Li-ion coin cell with LFP and graphite electrode. We observed a rapid capacity fade after the first delithiation cycle. To investigate TM ion dissolution, we established a baseline IR spectrum for various TM solvation states (such as Mn and Ni) by measuring concentration-dependent IR spectra. This baseline spectrum helps us detect TM ion dissolution during battery cycling. In this work, we discuss in detail the effect of TM ions on the electrochemical performance of Li-ion batteries and the detection of TM ions during battery cycling using in-situ FTIR spectroscopy. We will compare TM dissolution between coated and uncoated cathodes to examine the effect of cathode coatings to mitigate degradation due to TM dissolution and cross-over from cathode to anode. References: (1) Zhan, C.; Wu, T.; Lu, J.; Amine, K. Dissolution, migration, anddeposition of transition metal ions in Li-ion batteries exemplified byMn-based cathodes - a critical review. Energy Environ. Sci. 2018, 11,243-257. (2) Jung, R.; Linsenmann, F.; Thomas, R.; Wandt, J.; Solchenbach,S.; Maglia, F.; Stinner, C.; Tromp, M.; Gasteiger, H. A. Nickel,Manganese, and Cobalt Dissolution from Ni-Rich NMC and TheirEffects on NMC622-Graphite Cells. J. Electrochem. Soc. 2019, 166,A378-A389. (3) Zhao, L.; Chenard, E.; Capraz, O. O.; Sottos, N. R.; White, S.R. Direct Detection of Manganese Ions in Organic Electrolyte by UV-Vis Spectroscopy. J. Electrochem. Soc. 2018, 165, A345-A348 (4) Zhang, Y.; Hu, A.; Xia, D.; Hwang, S.; Sainio, S.; Nordlund, D.;Michel, F. M.; Moore, R. B.; Li, L.; Lin, F. Operando characterization and regulation of metal dissolution and redeposition dynamics nearbattery electrode surface. Nat. Nanotechnol. 2023, 18, 790.

25 ENERGY STORAGE↗
DOE OSTI2020

Materials Data on Tm by Materials Project

Tm is alpha La structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded to twelve Tm atoms to form a mixture of edge, face, and corner-sharing TmTm12 cuboctahedra. There are six shorter (3.48 Å) and six longer (3.50 Å) Tm–Tm bond lengths. In the second Tm site, Tm is bonded to twelve Tm atoms to form a mixture of edge, face, and corner-sharing TmTm12 cuboctahedra. All Tm–Tm bond lengths are 3.50 Å.

36 MATERIALS SCIENCE↗
NASA NTRS1989

Development of flashlamp-pumped Q-switched Ho:Tm:Cr:YAG lasers for mid-infrared LIDAR application

A flashlamp-pumped 2.1 micron Ho:Tm:Cr:YAG laser was studied for both normal mode and Q-switched operations under a wide variety of experimental conditions in order to optimize performance. Laser output energy, slope efficiency, threshold and pulselength were determined as a function of operating temperature, output mirror reflectivity, input electrical energy and Q-switch opening time. The measured normal-mode laser thresholds of a Ho(3+) (0.45 atomic percent):Tm(3+) (2.5 atomic percent):Cr(3+) (0.8 atomic percent):YAG crystal ranged form 26 to 50 J between 120 and 200 K with slope efficiencies up to 0.36 percent with a 60 percent reflective output mirror. Under Q-switched operation the slope efficiency was 90 percent of the normal-mode result. Development of solid state lasers with Ho(3+), Tm(3+) and/or Er(3+) doped crystals has been pursued by NASA for eye-dafe mid-infrared LIDAR (light detection and ranging) application. As a part of the project, the authors have been working on evaluating Ho(3+):Tm(3+):Cr(3+):YAG crystals for normal-mode and Q-switched 2.1 micron laser operations in order to determine an optimum Tm(3+) concentration under flashlamp pumping conditions. Lasing properties of the Ho(3+) in the mid-infrared region have been studied by many research groups since the early 1960's. However, the technology of those lasers is still premature for lidar application. In order to overcome the inefficiency related to narrow absorption bands of the Ho(3+), Tm(3+) and Er(3+), the erbium has been replaced by chromium. The improvement in flashlamp-pumped Ho(3+) laser efficiency has been demonstrated recently by several research groups by utilizing the broad absorption spectrum of Cr(3+) which covers the flashlamp's emission spectrum. Efficient energy transfer to the Tm(3+) and then the Ho(3+) occurs subsequently. It is known that high Tm(3+) concentration and low Ho(3+) concentration are preferred to achieve a quantum efficiency approaching two and to avoid large reabsorption losses. However, determination of the optimum Tm(3+) concentration required to ensure efficient energy transfer from Cr(3+) to Tm(3+) and from Tm(3+) to Ho(3+) has not been made in the Ho:Tm:CR:YAG crystal. The results obtained so far are given.

Choi, Young S.↗
DOE OSTI2020

Materials Data on Tm(TiGa2)2 by Materials Project

Tm(TiGa2)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm is bonded in a distorted square co-planar geometry to twelve Ga atoms. There are four shorter (2.88 Å) and eight longer (3.31 Å) Tm–Ga bond lengths. Ti is bonded in a 10-coordinate geometry to two equivalent Ti and eight Ga atoms. Both Ti–Ti bond lengths are 2.72 Å. All Ti–Ga bond lengths are 2.79 Å. There are seven inequivalent Ga sites. In the first Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms. There are two shorter (2.67 Å) and two longer (2.89 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms. The Ga–Ga bond length is 2.67 Å. In the third Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms. The Ga–Ga bond length is 2.67 Å. In the fourth Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms. There are two shorter (2.67 Å) and two longer (2.89 Å) Ga–Ga bond lengths. In the fifth Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms. The Ga–Ga bond length is 2.67 Å. In the sixth Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms. Both Ga–Ga bond lengths are 2.89 Å. In the seventh Ga site, Ga is bonded in a 11-coordinate geometry to three equivalent Tm, four equivalent Ti, and four Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(GeRh2)2 by Materials Project

Tm(Rh2Ge)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Tm is bonded in a 2-coordinate geometry to eleven Rh and two equivalent Ge atoms. There are a spread of Tm–Rh bond distances ranging from 2.79–3.21 Å. Both Tm–Ge bond lengths are 3.04 Å. There are four inequivalent Rh sites. In the first Rh site, Rh is bonded in a 12-coordinate geometry to three equivalent Tm and four Ge atoms. There are a spread of Rh–Ge bond distances ranging from 2.45–2.64 Å. In the second Rh site, Rh is bonded in a 5-coordinate geometry to three equivalent Tm, three equivalent Rh, and three Ge atoms. There are one shorter (3.00 Å) and two longer (3.01 Å) Rh–Rh bond lengths. There are one shorter (2.49 Å) and two longer (2.55 Å) Rh–Ge bond lengths. In the third Rh site, Rh is bonded in a 1-coordinate geometry to two equivalent Tm, three equivalent Rh, and four Ge atoms. There are two shorter (2.86 Å) and one longer (2.92 Å) Rh–Rh bond lengths. There are a spread of Rh–Ge bond distances ranging from 2.40–2.66 Å. In the fourth Rh site, Rh is bonded in a 4-coordinate geometry to three equivalent Tm, six Rh, and four Ge atoms. There are a spread of Rh–Ge bond distances ranging from 2.48–2.70 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to two equivalent Tm and seven Rh atoms. In the second Ge site, Ge is bonded in a 8-coordinate geometry to eight Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(MnAl)6 by Materials Project

Tm(MnAl)6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Tm is bonded in a 8-coordinate geometry to twelve Mn and eight Al atoms. There are four shorter (3.19 Å) and eight longer (3.30 Å) Tm–Mn bond lengths. There are a spread of Tm–Al bond distances ranging from 2.88–3.02 Å. There are two inequivalent Mn sites. In the first Mn site, Mn is bonded in a 12-coordinate geometry to two equivalent Tm, four Mn, and six Al atoms. There are two shorter (2.46 Å) and two longer (2.51 Å) Mn–Mn bond lengths. There are a spread of Mn–Al bond distances ranging from 2.52–2.62 Å. In the second Mn site, Mn is bonded to two equivalent Tm, four equivalent Mn, and six Al atoms to form a mixture of distorted corner, edge, and face-sharing MnTm2Mn4Al6 cuboctahedra. There are a spread of Mn–Al bond distances ranging from 2.61–2.64 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Tm, six Mn, and three Al atoms. There are one shorter (2.69 Å) and two longer (2.80 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Tm, six Mn, and three Al atoms. There are one shorter (2.80 Å) and two longer (3.01 Å) Al–Al bond lengths. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tm, six Mn, and four Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(AlCr)6 by Materials Project

Tm(CrAl)6 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Tm is bonded in a 8-coordinate geometry to twelve Cr and eight Al atoms. There are four shorter (3.29 Å) and eight longer (3.34 Å) Tm–Cr bond lengths. There are a spread of Tm–Al bond distances ranging from 2.93–3.03 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded to two equivalent Tm, four Cr, and six Al atoms to form a mixture of distorted corner, edge, and face-sharing CrTm2Al6Cr4 cuboctahedra. There are two shorter (2.51 Å) and two longer (2.53 Å) Cr–Cr bond lengths. There are a spread of Cr–Al bond distances ranging from 2.59–2.67 Å. In the second Cr site, Cr is bonded to two equivalent Tm, four equivalent Cr, and six Al atoms to form a mixture of distorted corner, edge, and face-sharing CrTm2Al6Cr4 cuboctahedra. There are a spread of Cr–Al bond distances ranging from 2.65–2.69 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Tm, six Cr, and three Al atoms. There are one shorter (2.68 Å) and two longer (2.85 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 8-coordinate geometry to one Tm, six Cr, and two equivalent Al atoms. Both Al–Al bond lengths are 3.05 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tm, six Cr, and four Al atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1985

Preliminary Study of Information Extraction of LANDSAT TM Data for a Suburban/regional Test Site

A substantial amount of spectral information is available from TM (as compared to MSS) data for a 14.25 square km area between Beltsville and Laurel, Maryland. Large buildings and street patterns were resolved in the TM imagery. While there was added information content in TM data for discriminating surburban/regional land cover, characteristics of MSS can improve land cover discrimination over TM when conventional classification procedures are used on digital data. The improved qualitization of TM is likely valuable in situations where there are spectral similarities between classes. The spatial resolution in TM decreased land cover discrimination as a result of increased within class variability. For many general digital evaluations, inclusion of four bands representing the four spectral regions can provide much useful land cover discrimination. Inclusion of TM 6 indicates an improvement in spectral class discrimination. Of primary spectral importance is the discrimination between water, vegetative surfaces, and impervious surfaces due to differences in thermal properties. Results from the principle component transformed data clearly indicates additional information content in TM over MSS.

Toll, D. L.↗