scholarly journals In Situ Diagnostics of Damage Accumulation in Ni-Based Superalloys Using High-Temperature Computed Tomography

2018 ◽  
Vol 49 (9) ◽  
pp. 4274-4289 ◽  
Author(s):  
K. Kageyama ◽  
F. Adziman ◽  
E. Alabort ◽  
T. Sui ◽  
A. M. Korsunsky ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Temperature ◽  
Damage Accumulation ◽  
In Situ Diagnostics

scholarly journals Effect of High-Temperature Pavement Paving on Fatigue Durability of Bearing-Supported Steel Decks

2020 ◽  
Vol 10 (20) ◽  
pp. 7196
Author(s):  
Qiudong Wang ◽  
Bohai Ji ◽  
Zhongqiu Fu ◽  
Hao Wang
Keyword(s):  
High Temperature ◽  
Fatigue Damage ◽  
Temperature Stress ◽  
Damage Accumulation ◽  
Considerable Effect ◽  
In Situ Monitoring ◽  
Fatigue Durability ◽  
Residual Temperature ◽  
Fatigue Damage Accumulation

Orthotropic steel deck (OSD) is a better choice for urban bridges and the replacement of damaged concrete slabs. Gussasphalt concrete (GAC) is usually adopted as the asphalt surfacing; however, the paving temperature of GAC is high, which will affect the fatigue durability of fatigable welds in OSD. In this study, such influence of high-temperature pavement paving was comprehensively investigated based on in-situ monitoring and numerical analysis. The temperature of OSD and displacement of bearings were investigated based on the monitored data and numerical results. After that, the deformation and residual temperature stress of OSD during the paving process were analyzed. On this basis, the effect of residual temperature stress on fatigue damage accumulation of OSD was investigated and discussed. Results show that the uplift and expanded deformation of OSD arise during the paving process, leading to the displacement of bearings. Residual displacement of bearings, as well as the residual temperature stress at fatigable details of OSD, is observed. The residual temperature stress has considerable effect on fatigue damage accumulation at rib-deck weld. A fatigue damage amplification factor of 1.1 is recommended for taking into consideration of the adverse effect of high-temperature pavement paving.

Adaptive Process Control and In-Situ Diagnostics for High Temperature PEM MEA Manufacturing

2010 ◽  
Author(s):  
Justin Gullotta ◽  
Lakshmi Krishnan ◽  
Dylan Share ◽  
Daniel Walczyk ◽  
Raymond Puffer
Keyword(s):  
High Temperature ◽  
Real Time ◽  
Complex Impedance ◽  
Impedance Measurement ◽  
Proton Exchange ◽  
Unit Process ◽  
Adaptive Process ◽  
In Situ Diagnostics ◽  
High Temperature Pem

The most critical step in high temperature proton exchange membrane (PEM) MEA manufacturing is sealing of the membrane between the two electrodes. This sealing process is typically conducted using a precision hydraulic thermal press. In order to achieve cost-effective high-volume MEA manufacturing, it is important to reduce the variability in MEA performance due to variations in incoming material properties and dimensions, and to reduce the unit process cycle time. This paper explains the application of real time adaptive process controls (APC) combined with effective in-situ diagnostics during the MEA sealing process to achieve greater uniformity and performance of high temperature PEM MEAs. The in-situ impedance measurement is carried out in a precision thermal press using a milliohmmeter by reading the complex impedance of the MEA at 1 kHz as the components of the MEA are sealed. This signal is then used to adjust the pressing process parameters in real time to achieve more uniform MEA performance. An experiment was carried out in an attempt to identify the impedance parameter which correlated most closely with the MEA’s future performance. Using these impedance parameters during pressing, we are able to reliably produce MEAs using the real time APC technique that perform consistently in a single cell test fixture with more than a 50% reduction in pressing time.

Electrochemistry and Dynamic Ionography of Self-Propagating High-Temperature Synthesis (SHS)

2007 ◽  
Vol 555 ◽  
pp. 73-81
Author(s):  
Maxim V. Kuznetsov ◽  
Yuri G. Morozov ◽  
Ivan P. Parkin
Keyword(s):  
High Temperature ◽  
Chemical Reactions ◽  
Alkaline Earth ◽  
Complex Oxides ◽  
Temperature Synthesis ◽  
Group Vi ◽  
Electrochemical Processes ◽  
High Temperature Synthesis ◽  
In Situ Diagnostics

The results of a new potentiometric technique for in situ diagnostics of self-propagating high-temperature synthesis (SHS) of different complex oxides are presented. This technique is based on electrochemical processes. The characteristic peaks attributed to the electric responses from cation streams of alkali, alkaline-earth and some elements of group VI are discovered and the respective routes of the corresponding chemical reactions found.

The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

1990 ◽  
Vol 48 (4) ◽  
pp. 664-665
Author(s):  
N. Rozhanski ◽  
A. Barg
Keyword(s):  
High Temperature ◽  
Crystallization Temperature ◽  
Diffusion Barriers ◽  
Sio2 Layer ◽  
Si Substrate ◽  
Cross Sectional ◽  
Plan View ◽  
Temperature Range ◽  
Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

Concepts for In Situ Diagnostics in Analog Microelectronic Circuits

2007 ◽  
Author(s):  
Ted Kolasa ◽  
Alfredo Mendoza
Keyword(s):  
Analog Circuits ◽  
System Architecture ◽  
Analog Circuit ◽  
Fault Localization ◽  
Diagnostic System ◽  
Diagnostic Capability ◽  
Common Signal ◽  
Diagnostic Capabilities ◽  
In Situ Diagnostics

Abstract Comprehensive in situ (designed-in) diagnostic capabilities have been incorporated into digital microelectronic systems for years, yet similar capabilities are not commonly incorporated into the design of analog microelectronics. And as feature sizes shrink and back end interconnect metallization becomes more complex, the need for effective diagnostics for analog circuits becomes ever more critical. This paper presents concepts for incorporating in situ diagnostic capability into analog circuit designs. Aspects of analog diagnostic system architecture are discussed as well as nodal measurement scenarios for common signal types. As microelectronic feature sizes continue to shrink, diagnostic capabilities such as those presented here will become essential to the process of fault localization in analog circuits.

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