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In this study, static and fatigue tests were conducted using coach-peel, cross-tension and tensile–shear specimens with Al-5052 plates for evaluation of the fatigue strength of the SPR joints. For the coach-peel, cross-tension and tensile–shear geometries, the ratios of the fatigue endurance limit to static strength were 11%, 14% and 34%, respectively, assuming fatigue cycles of 10 6 for an infinite lifetime. The equivalent stress intensity factor range can properly predict the current experimental fatigue lifetime. Fatigue crack initiation occurred due to fretting damage between the upper and lower sheets and between the rivet and these sheets. [ABSTRACT FROM AUTHOR]

An efficient method for constructing multiple candidate finite element (FE) models which are consistent with the measured dynamic properties of a civil structure is presented. A parameterised sensitivity-based FE model updating method was developed to permit a feasible FE model set for the target structure to be produced. In this method, an aggregated multi-objective function, which is defined by the weighted sum of the error functions, is parameterised by its relative weighting factors. By introducing multiple parameter sets for the weighting factors, a number of optimal updated FE models are produced that permit both the natural frequency errors and mode shape errors to be simultaneously minimised. The effectiveness of the proposed method is illustrated by an example using an existing cable-stayed bridge. The findings show that error-minimised, well-distributed FE models can be obtained in terms of modal frequency errors and mode shape errors. The high quality of the candidate model sets is also verified by observations showing that the distributions of the structural parameters are consistent through each updated FE models, and the characteristic features of the target structure such as non-symmetric mode shapes are relatively well captured. [ABSTRACT FROM AUTHOR]

Two new aryl-tetralin lignan glycosides, linderanosides A and B ( 1 and 2, resp.), and a new dihydrobenzofuran neolignan glycoside, linderanoside C ( 3), together with five known lignan derivatives ( 4- 8) were isolated from the trunk of Lindera glauca. The structures of these new compounds were determined through spectroscopic analyses, including extensive 2D-NMR data and acid hydrolysis. The absolute configurations of the compounds were clarified by circular dichroism (CD) spectroscopic studies. Compounds 1- 8 were evaluated for their cytotoxicity against A549 (non-small cell lung adenocarcinoma), SK-OV-3 (ovarian cancer cells), A498 (human kidney epithelial cells), and HCT-15 (colon cancer cells) human tumor cell lines using sulforhodamine B assays in vitro. [ABSTRACT FROM AUTHOR]

Shear tests with velocities between 0.5 m/s and 2.5 m/s were conducted to investigate the deformation characteristics of 0.76 mm lead-free Sn-3Ag-0.5Cu solder ball joints after thermal aging at 373 K up to 1000 h. A scanning electron microscope equipped with energy dispersive spectroscopy was then used to examine the fracture surfaces and microstructures of the solder joints. The results showed that the main failure mode of the solder joints was the brittle interfacial fracture mode with cleavage failure in the intermetallic compound (IMC). The maximum shear strength and the fracture toughness ( K) of the solder joint decreased substantially after aging for the initial aging time, after which they decreased gradually with further aging or an increase in the strain rate. The evolution of the IMC layer when it was thicker and had coarser nodules due to thermal aging was the primary cause of the reduction in the shear strength and fracture toughness in this study. [ABSTRACT FROM AUTHOR]

High-resolution and three-dimensional X-ray imaging is becoming more and more popular. An X-ray microtomographic system with a CMOS image sensor has been developed. We have developed a novel area X-ray detector with a cost-effective CMOS image sensor. The sensing area of the detector is 55 x 55 [mm.sup.2] and the light from the phosphor screen is collected to the CMOS image sensor by a carefully designed optical system. Six lenses are assembled to reduce the radiation damage effect and increase the resolution and sensitivity. A microfocus X-ray tube that can reach up to 5 [micro]m of focal spot size and microprecision motor system that can move in x-y-z directions for both alignment and magnification and rotate the object have been adopted. A conventional three-dimensional cone-beam Feldkamp reconstruction algorithm was used and a human cancellous bone has been imaged with this system. Currently, the resolution of this system is about 40 [micro]m but the application in microtomography seems very promising using this CMOS X-ray detector. Index Terms--CMOS, cone-beam CT, micro-CT, microtomography, X-ray detector.

The Bremsstrahlung spectrum from a 6-MV linear accelerator (LINAC) was obtained and used as an input X-ray source in the simulation to estimate several important physical quantities of the detector in a therapeutic X-ray portal imaging system, such as quantum and energy absorption efficiencies, Swank factor, and detective quantum efficiency (DQE). In addition, we have obtained a spatial distribution of energy deposit within the detector, resulting in a spatial-frequency-dependent DQE. From the simulation results, it is found that the use of metal plate largely enhances the energy absorption, leading to a large output signal. However, considering the noise properties, the presence of a metal plate degrades the DQE at nonzero spatial frequencies because the detector absorption noise is dominated by the quantum absorption. We have verified our simulation results by comparison with experimental measurements and results from other works.

The Scientific Committee (SC, chaired by Prof. Ho-Kyung Kim) collected 54 papers under the theme of "Risk Intelligence of Infrastructures". SC organized three keynote sessions, and 11 general sessions from 9 am to 7:30 pm in KST. The session chairs monitored the Zoom Webinar platform and moderated online/on-site Q&A at the end of each session. [Extracted from the article]

Static tensile and fatigue tests were conducted using tensile-shear specimens to evaluate the fatigue strength of clinched lap joints of a cold rolled mild steel sheet. The maximum tensile force (= holding force) of the specimen produced at the optimal punching force was 70 kN. The fatigue endurance limit (= 760 N) approached 43% of the maximum tensile load (= 1750 N) at a load ratio of 0.1, suggesting that the fatigue limit is approximately half of the value of the maximum tensile force. The FEM analysis showed that at the fatigue endurance limit, the maximum von Mises stress of 373 MPa is very close to the ultimate tensile strength of the cold rolled mild steel sheet (= 382 MPa). [ABSTRACT FROM AUTHOR]

Purpose: X-ray digital subtraction angiography (DSA) is widely used for vascular imaging. However, the need to subtract a mask image can result in motion artifacts and compromised image quality. The current interest in energy-resolving photon-counting (EPC) detectors offers the promise of eliminating motion artifacts and other advanced applications using a single exposure. The authors describe a method of assessing the iodine signal-to-noise ratio (SNR) that may be achieved with energy-resolved angiography (ERA) to enable a direct comparison with other approaches including DSA and dual-energy angiography for the same patient exposure. Methods: A linearized noise-propagation approach, combined with linear expressions of dual-energy and energy-resolved imaging, is used to describe the iodine SNR. The results were validated by a Monte Carlo calculation for all three approaches and compared visually for dual-energy and DSA imaging using a simple angiographic phantom with a CsI-based flat-panel detector. Results: The linearized SNR calculations show excellent agreement with Monte Carlo results. While dual-energy methods require an increased tube heat load of 2× to 4× compared to DSA, and photon-counting detectors are not yet ready for angiographic imaging, the available iodine SNR for both methods as tested is within 10% of that of conventional DSA for the same patient exposure over a wide range of patient thicknesses and iodine concentrations. Conclusions: While the energy-based methods are not necessarily optimized and further improvements are likely, the linearized noise-propagation analysis provides the theoretical framework of a level playing field for optimization studies and comparison with conventional DSA. It is concluded that both dual-energy and photon-counting approaches have the potential to provide similar angiographic image quality to DSA. [ABSTRACT FROM AUTHOR]

Abstract: The influences of stress and temperature on creep deformation behavior and the creep crack growth rates of the super α2 Ti3Al alloy were investigated with respect to its safe application at high temperatures. In a temperature range of 1033–1093K at low applied stress levels, the stress exponent was equal to 1.5. At an intermediate stress range (10−3 < σ/E <3×10−3), a stress exponent of 3.3 was observed. As the applied stress was increased, the stress exponent changed from 3.3 to 4.4. The high temperature crack growth rate of the Ti3Al alloy can be correlated with stress intensity factor K rather than C∗ at 1033K due to environmental embrittlement. [Copyright &y& Elsevier]