An improved analyzer for measuring in-situ gas pressure in sealed quartz tube, and absolute and differential temperatures in heat treatments up to high temperatures

2021 ◽  
Vol 16 (07) ◽  
pp. P07054
Author(s):  
A.G. Cunha ◽  
M.B. Cevolani ◽  
C.W. Cremasco ◽  
M.A. Schettino ◽  
T.E.P. Bueno ◽  
...  
2000 ◽  
Vol 13 (11) ◽  
pp. 1549-1552 ◽  
Author(s):  
A G Cunha ◽  
A Sin ◽  
X Granados ◽  
A Calleja ◽  
M T D Orlando ◽  
...  

Author(s):  
Z. L. Wang ◽  
J. Bentley

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.


2021 ◽  
Vol 546 ◽  
pp. 149019
Author(s):  
Bao Jin ◽  
Jun Zhao ◽  
Guangyan Chen ◽  
Yongyong He ◽  
Yiyao Huang ◽  
...  

2014 ◽  
Vol 783-786 ◽  
pp. 2097-2102 ◽  
Author(s):  
Svea Mayer ◽  
Emanuel Schwaighofer ◽  
Martin Schloffer ◽  
Helmut Clemens

Urgent needs concerning energy efficiency and environmental politics require novel approaches to materials design. One recent example is thereby the implementation of light-weight intermetallic titanium aluminides as structural materials for the application in turbine blades of aero-engines as well as in turbocharger turbine wheels for the next generation of automotive engines. Each production process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and / or subsequent heat-treatments. To develop sound and sustainable processing routes, knowledge on solidification processes and phase transformation sequences in advanced TiAl alloys is fundamental. Therefore, in-situ diffraction techniques employing synchrotron radiation and neutrons were used for establishing phase fraction diagrams, investigating advanced heat-treatments as well as for optimizing thermo-mechanical processing. Summarizing all results a consistent picture regarding microstructure formation and its impact on mechanical properties in advanced multi-phase TiAl alloys can be given.


2016 ◽  
Vol 8 (21) ◽  
pp. 13637-13645 ◽  
Author(s):  
Michael Desanker ◽  
Blake Johnson ◽  
Afif M. Seyam ◽  
Yip-Wah Chung ◽  
Hassan S. Bazzi ◽  
...  

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2535
Author(s):  
Jose Lucas Peñalver-Soto ◽  
Alberto Garre ◽  
Arantxa Aznar ◽  
Pablo S. Fernández ◽  
Jose A. Egea

In food processes, optimizing processing parameters is crucial to ensure food safety, maximize food quality, and minimize the formation of potentially toxigenic compounds. This research focuses on the simultaneous impacts that severe heat treatments applied to food may have on the formation of harmful chemicals and on microbiological safety. The case studies analysed consider the appearance/synthesis of acrylamide after a sterilization heat treatment for two different foods: pureed potato and prune juice, using Geobacillus stearothermophilus as an indicator. It presents two contradictory situations: on the one hand, the application of a high-temperature treatment to a low acid food with G. stearothermophilus spores causes their inactivation, reaching food safety and stability from a microbiological point of view. On the other hand, high temperatures favour the appearance of acrylamide. In this way, the two objectives (microbiological safety and acrylamide production) are opposed. In this work, we analyse the effects of high-temperature thermal treatments (isothermal conditions between 120 and 135 °C) in food from two perspectives: microbiological safety/stability and acrylamide production. After analysing both objectives simultaneously, it is concluded that, contrary to what is expected, heat treatments at higher temperatures result in lower acrylamide production for the same level of microbial inactivation. This is due to the different dynamics and sensitivities of the processes at high temperatures. These results, as well as the presented methodology, can be a basis of analysis for decision makers to design heat treatments that ensure food safety while minimizing the amount of acrylamide (or other harmful substances) produced.


1996 ◽  
Vol 440 ◽  
Author(s):  
T. Wagner

AbstractThe growth and microstructural evolution of Nb thin films on the basal plane of α-Al2O3 were studied at different growth temperatures. The influence of island orientation, density, and misfit strain energy on the growth behavior of Nb films on (0001)α-Al2O3 at high temperatures has been investigated. The films were grown by MBE at 900°C and 1100°C. At these temperatures the Nb grows in the Volmer-Weber growth mode on the basal plane. In-situ reflection high energy electron diffraction (RHEED), Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) investigations revealed that in the initial growth stage, Nb nuclei with different epitaxial orientations were formed. This leads to different orientations of thicker Nb films at different growth temperatures. At a growth temperature of 900°C the Nb{111} planes are parallel to the sapphire basal plane whereas at 1100°C Nb grows with the {110) planes parallel to the basal plane of sapphire. The formation of two different epitaxial orientations of thick Nb films can only be explained by considering both the change in the total density of Nb islands with temperature and the influence of island size on their total energy.


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