A thermal stress test of the depth-graded Pt/C reflectors used in the ASTRO-H Hard X-ray Telescope (HXT)

2012 ◽  
Author(s):  
Yoshitomo Maeda ◽  
Kou Ichihara ◽  
Yu Shionome ◽  
Takuro Sato ◽  
Takayuki Hayashi ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Stress Test ◽  
X Ray

scholarly journals Operando SAXS Study of a Pt/C Fuel Cell Catalyst with an X-ray Laboratory Source

2021 ◽  
Author(s):  
Johanna Schröder ◽  
Jonathan Quinson ◽  
Jacob J. K. Kirkensgaard ◽  
Matthias Arenz
Keyword(s):  
Fuel Cell ◽  
Background Subtraction ◽  
Stress Test ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Support ◽  
Grazing Incidence ◽  
Saxs Data ◽  
X Ray ◽  
Fuel Cell Catalysts

Small angle X-ray scattering (SAXS) is a powerful technique to investigate the degradation of catalyst materials. Ideally such investigations are performed <i>operando</i>, i.e., during a catalytic reaction. An example of <i>operando </i>measurements is to observe the degradation of fuel cell catalysts during an accelerated stress test (AST). Fuel cell catalysts consist of Pt or Pt alloy nanoparticles (NPs) supported on a high surface area carbon. A key challenge of operando SAXS measurements is a proper background subtraction of the carbon support to extract the information of the size distribution of the Pt NPs as a function of the AST treatment. Typically, such operando studies require the use of synchrotron facilities. The background measurement can then be performed by anomalous SAXS (aSAXS) or in a grazing incidence con-figuration. In this work we present a proof-of-concept study demonstrating the use of a laboratory X-ray diffractometer for <i>operando </i>SAXS. Data acquisition of <i>operando </i>SAXS with a laboratory X-ray diffractometer is desirable due to the general challenging and limited accessibility of synchrotron facilities. They become even more crucial under the ongoing and foreseen restrictions related to the COVID-19 pandemic. Although, it is not the aim to completely replace synchrotron-based studies, it is shown that the background subtraction can be achieved by a simple experimental consideration in the setup that can ultimately facilitate <i>operando </i>SAXS measurements at a synchrotron facility. <br>

scholarly journals Effect of LiNO3 on Expansion of Alkali–Silica Reaction in Rock Prisms and Concrete Microbars Prepared by Sandstone

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1150 ◽  
Author(s):  
Jinxin Liu ◽  
Lanqing Yu ◽  
Min Deng
Keyword(s):  
Electron Microscope ◽  
Critical Concentration ◽  
Stress Test ◽  
Molar Ratio ◽  
Alkali Silica Reaction ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Long Period ◽  
Scanning Electron

The aim of this research is to investigate the effect of LiNO3 on the alkali–silica reaction (ASR) expansion of reactive sandstone and the mechanism through which this occurs. This paper presents the results from tests carried out on rock prisms and concrete microbars prepared by sandstone and LiNO3. The findings show that LiNO3 does not decrease the expansion of these samples unless the molar ratio of [Li]/[Na + K] exceeds 1.66, and the expansion is greatly increased when its concentration is below this critical concentration. The expansion stress test proves that Li2SiO3 is obviously expansive. X-ray diffraction (XRD) and scanning electron microscope (SEM) results indicate that LiNO3 reacts with the microcrystalline quartz inside sandstone, inhibiting the formation of ASR gel, and the formation of Li2SiO3 causes larger expansion. A high concentration of LiNO3 might inhibit the ASR reaction in the early stages, and the formation of Li2SiO3 causes expansion and cracks in concrete after a long period of time.

The Influences of Different Temperature Histories on the Assessment of Cracking Resistance Based on the Concrete Thermal Stress Test

2014 ◽  
Vol 496-500 ◽  
pp. 2426-2430
Author(s):  
Xue Feng Song ◽  
Ying Fei Wang ◽  
Chao Li
Keyword(s):  
Thermal Stress ◽  
Temperature Control ◽  
Stress Test ◽  
Adiabatic Heating ◽  
Control Mode ◽  
Stress Tests ◽  
Cracking Resistance ◽  
Data Matching ◽  
Empirical Tests ◽  
Heating Mode

This paper studied the influences of different temperature histories on the assessment of cracking resistance based on the thermal stress tests, and also initially considered and discussed the effects of several empirical tests on thermal stress tests, including approximate adiabatic heating mode, temperature control mode, archived data matching mode, followed by some proposals regarding the standardizing research of thermal stress test of concrete.

The Ulnocarpal Stress Test in the Diagnosis of Ulnar-Sided Wrist Pain

1997 ◽  
Vol 22 (6) ◽  
pp. 719-723 ◽  
Author(s):  
R. NAKAMURA ◽  
E. HORII ◽  
T. IMAEDA ◽  
E. NAKAO ◽  
H. KATO ◽  
...  
Keyword(s):  
Bone Scan ◽  
Stress Test ◽  
Final Diagnosis ◽  
Wrist Pain ◽  
Wrist Arthroscopy ◽  
Resonance Imaging ◽  
Provocative Test ◽  
X Ray ◽  
Ligament Tear ◽  
Free Body

Forty-five patients with persistent ulnar-sided wrist pain and a positive ulnocarpal stress test were investigated by X-ray, arthrography, 99mTechnetium bone scanning, magnetic resonance imaging and wrist arthroscopy. Ulnar wrist pathology was positively identified in nine of 45 patients by X-ray, 18 of 37 by arthrography, 19 of 27 by bone scan, four of 33 by MRI, and in all 45 patients by arthroscopy. The final diagnosis was ulnocarpal abutment syndrome in 28 patients, traumatic triangular fibro-cartilage (TFC) tear in six, lunotriquetral (LT) ligament tear in five, TFC and LT ligament tear in one, wrist arthritis in four and cartilaginous free body in one. The ulnocarpal stress test is a useful provocative test, and a positive test suggests the presence of ulnar-sided wrist pathology. The test is sufficiently sensitive to warrant further investigation by arthroscopy.

The Effect of the Different Constraint Degree on the Temperature Stress and Strain of Concrete

2015 ◽  
Vol 727-728 ◽  
pp. 305-308
Author(s):  
Xue Feng Song ◽  
Zhi Hong Fan ◽  
Chao Li ◽  
Bao Lan Zhang
Keyword(s):  
Thermal Stress ◽  
Temperature Stress ◽  
Stress Test ◽  
Stress And Strain ◽  
Stress Tests

This paperstudied the development of stress and strain influences by different constraintdegree based on the concrete thermal stress tests. furthermore, suggested thevalue range of the constraint degree in the thermal stress test.

Thermal stress test for PLED

2010 ◽  
Author(s):  
B. K. Yap ◽  
S. P. Koh ◽  
S. K. Tiong ◽  
C. N. Ong
Keyword(s):  
Thermal Stress ◽  
Stress Test

Temperature profiles obtained in thermoelastic stress test for different frequencies

2017 ◽  
Vol 8 (1) ◽  
pp. 51-62
Author(s):  
António José Ramos Silva ◽  
P.M.G. Moreira ◽  
Mario A.P. Vaz ◽  
Joaquim Gabriel
Keyword(s):  
Thermal Stress ◽  
Temperature Variation ◽  
Cyclic Load ◽  
Mechanical Load ◽  
Fatigue Cracks ◽  
Stress Test ◽  
Stress Profile ◽  
Stress Tests ◽  
Content Type ◽  
Load Frequency

Purpose Maintenance is one of the most critical and expensive operations during the life cycle of metallic structures, in particular in the aeronautic industry. However, early detection of fatigue cracks is one of the most demanding operations in global maintenance procedures. In this context, non-destructive testing using image techniques may represent one of the best solutions in such situations, especially thermal stress analyses (TSA) using infrared thermography. The purpose of this paper is to access and characterize the main stress profile calculated through temperature variation, for different load frequencies. Design/methodology/approach In this paper, a cyclic load is applied to an aluminum sample component while infrared thermal image is being acquired. According to the literature and experiments, a cyclic load applied to a material results in cyclic temperature variation. Findings Frequency has been shown to be an important parameter in TSA evaluations, increasing the measured stress profile amplitude. The loading stimulation frequency and the maximum stress recorded show a good correlation (R2 higher than 0.995). It was verified that further tests and modeling should be performed to fully comprehend the influence of load frequency and to create a standard to conduct thermal stress tests. Originality/value This work revealed that the current infrared technology is capable of reaching far more detailed thermal and spatial resolution than the one used in the development of TSA models. Thus, for the first time the influence of mechanical load frequency in the thermal profiles of TSA is visible and consequentially the measured mechanical stress.

Design and Application of MMM System for Welding Residual Stress Test

2012 ◽  
Vol 566 ◽  
pp. 534-537
Author(s):  
Hai Yan Xing ◽  
Ping Qin ◽  
Yan Min Lou
Keyword(s):  
Residual Stress ◽  
Stress Concentration ◽  
Stress Test ◽  
Object Oriented Programming ◽  
Welding Residual Stress ◽  
Testing System ◽  
Magnetic Memory ◽  
X Ray ◽  
Analysis And Evaluation ◽  
Examination Result

In order to apply metal magnetic memory (MMM) technology to welding residual stress testing, the MMM hardware and software system is designed. The software subsystem is based on object-oriented programming and the hardware subsystem is portable. The MMM system can test the welded joint residual stress distribution, residual stress concentration zones and defects at workshop. Moreover, the MMM testing system can output data to a computer not only for automatic evaluation but also for further analysis and evaluation with expert intervention. According to the trend of the MMM characteristic, the welding residual stress concentration and defects can be detected and evaluated. The field X-ray examination result is consistent with the result of the MMM testing system, which has proved the accuracy and engineering practicality of the MMM testing system.

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