High temperature studies of Urania in a thermal gradient

1969 ◽  
Vol 30 (1-2) ◽  
pp. 50-56 ◽  
Author(s):  
B.E. Fryxell ◽  
E.A. Aitken
Keyword(s):  
High Temperature ◽  
Thermal Gradient

Unsaturation Characterization of Polyolefins by NMR and Thermal Gradient NMR (TGNMR) with a High Temperature Cryoprobe

2012 ◽  
Vol 312 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Zhe Zhou ◽  
Rongjuan Cong ◽  
Yiyong He ◽  
Manjiri Paradkar ◽  
Mehmet Demirors ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Gradient

Metamorphism of the MacLean Lake and Central Metavolcanic belts, La Ronge domain, Trans-Hudson Orogen: pressure-temperature variations and tectonic implications

1998 ◽  
Vol 35 (8) ◽  
pp. 905-922 ◽  
Author(s):  
Haiming Yang ◽  
Kurt Kyser ◽  
Kevin Ansdell
Keyword(s):  
High Temperature ◽  
Thermal Gradient ◽  
Amphibolite Facies ◽  
Tectonic Zone ◽  
Thrust Sheet ◽  
Temperature Variations ◽  
High Thermal Gradient ◽  
Tectonic Implications ◽  
Peak Metamorphism ◽  
Peak Pressures

Metamorphic assemblages differ between the metasedimentary MacLean Lake belt and the adjacent Central Metavolcanic belt in the La Ronge domain, Trans-Hudson Orogen. The former consists of meta-arkoses, psammitic gneisses, metaconglomerates, and calc-silicate gneisses of upper amphibolite facies (600-740°C, 440-660 MPa) with local migmatization, whereas the latter is comprised mainly of metavolcanic and plutonic rocks, with minor metasedimentary schists of greenschist to lower amphibolite facies (480-630°C, 520-560 MPa). Petrographic evidence indicates that peak metamorphic conditions were reached towards the end of D1 deformation during which the Central Metavolcanic belt was thrust onto the MacLean Lake belt along the McLennan Lake tectonic zone, which separates the two belts. Peak metamorphic assemblages did not undergo retrograde alteration during D2 deformation, indicating that high temperature was maintained during D2 deformation. Differences in pressure (P) and temperature (T) between the northeastern and southwestern parts of the Central Metavolcanic belt may have resulted from tilting along strike after peak metamorphism. Peak temperatures increase gradually from the Central Metavolcanic belt to MacLean Lake belt across the McLennan Lake tectonic zone. Peak pressures in the two belts are similar, implying that the Central Metavolcanic belt thrust sheet was probably thin. The P-T data for the MacLean Lake belt indicate a relatively high thermal gradient (40-50°C/km), similar to that in the metasedimentary Kisseynew domain in the orogen.

Synchrotron XRD Measurements Mapping Internal Strains of Thermal Barrier Coatings During Thermal Gradient Mechanical Fatigue Loading

2014 ◽  
Author(s):  
Kevin Knipe ◽  
Albert C. Manero ◽  
Stephen Sofronsky ◽  
John Okasinski ◽  
Jonathan Almer ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Barrier Coatings ◽  
Mechanical Loading ◽  
Bond Coat ◽  
Thermal Gradient ◽  
Room Temperature ◽  
Material Behavior ◽  
Thermal Barrier ◽  
X Rays ◽  
Barrier Coatings

An understanding of the high temperature mechanics experienced in Thermal Barrier Coatings (TBC) during cycling conditions would be highly beneficial to extending the lifespan of the coatings. This study will present results obtained using synchrotron x-rays to measure depth resolved strains in the various layers of TBCs under thermal mechanical loading and a superposed thermal gradient. Tubular specimens, coated with Yttria Stabilized Zirconia (YSZ) and an aluminum containing nickel alloy as a bond coat both through Electron Beam - Physical Vapor Deposition (EBPVD), were subjected to external heating and controlled internal cooling generating a thermal gradient across the specimen’s wall. Temperatures at the external surface were in excess of 1000 °C. Throughout high temperature testing, 2-D high-resolution XRD strain measurements are taken at various locations through the entire depth of the coating layers. Across the YSZ a strain gradient was observed showing higher compressive strain at the interface to the bond coat than towards the surface. This behavior can be attributed to the specific microstructure of the EB-PVD-coating, which reveals higher porosity at the outer surface than at the interface to the bond coat, resulting in a lower in plane modulus near the surface. This location at the interface displays the most significant variation due to applied load at room temperature with this effect diminishing at elevated uniform temperatures. During thermal cycling with a thermal gradient and mechanical loading, the bond coat strain moves from a highly tensile state at room temperature to an initially compressive state at high temperature before relaxing to zero during the high temperature hold. The results of these experiments give insight into previously unseen material behavior at high temperature which can be used to develop an increased understanding of various failure modes and their causes.

A New Technique for Characterizing Comonomer Distribution in Polyolefins: High-Temperature Thermal Gradient Interaction Chromatography (HT-TGIC)

2011 ◽  
Vol 44 (8) ◽  
pp. 3062-3072 ◽  
Author(s):  
Rongjuan Cong ◽  
Willem deGroot ◽  
Al Parrott ◽  
Wallace Yau ◽  
Lonnie Hazlitt ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Gradient ◽  
New Technique ◽  
A New Technique

scholarly journals Nucleation Control in Physical Vapor Transport Growth of AlN Single Crystals on Polycrystal Tungsten Substrates

2019 ◽  
Vol 26 (2) ◽  
pp. 139-142
Author(s):  
Honglei WU ◽  
Zuoyan QIN ◽  
Xueyong TIAN ◽  
Zhenhua SUN ◽  
Baikui LI ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Temperature Field ◽  
High Temperature ◽  
Single Crystals ◽  
Thermal Gradient ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Heating Process ◽  
X Ray ◽  
Tungsten Substrate

The improved resistively-heated furnace with two heaters established a vertical thermal gradient to control nucleation during AlN single crystals Physical Vapor Transport (PVT) growth on polycrystal tungsten substrates. During the high temperature (> 1850 °C) heating process, the reverse temperature field (i.e., the temperature difference between the sublimation zone and the crystalline zone ΔT < 0) was obtained to reduce the number of nuclei on the tungsten substrate. During growth, the proper positive values of ΔT T were chosen to content the supersaturation values (0.25 < S < 0.3). The reverse temperature condition during high temperature (> 1850 °C) cooling was fulfilled to avoid recrystallization on grown AlN crystal. AlN single crystals made through the method were characterized by X-ray diffractions (XRD) and Raman spectroscopy.

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