PURPOSE The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. METHODS We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a ra...

The finite element alternating method is an attractive and efficient method for calculating the stress intensity factor of cracks emanating from fastener holes such as the problem of multiple site damage (MSD) at the fuselage skin of aging aircraft. While the alternating method has been used to solve various engineering problems in assessing the structural integrity of aging aircraft, this meth...

OBJECTIVE The objective of our study is to analyse (with the help of scanning electron microscopes) the quality of the dental root surface and the appearance of dental cracks after performing apical preparations using two different types of ultrasonic tips. STUDY DESIGN We used 32 single-rooted teeth that underwent a root canal and apical resection. Afterwards, the teeth were divided into 4 g...

In the coal mining process, the destabilization of loaded coal mass is a prerequisite for coal and rock dynamic disaster, and surface cracks of the coal and rock mass are important indicators, reflecting the current state of the coal body. The detection of surface cracks in the coal body plays an important role in coal mine safety monitoring. In this paper, a method for detecting the surface cr...

This paper presents a method for predicting initial trajectories of propagation of two separate fatigue cracks, which are developed under two perpendicular cyclic loads with phase difference between them. Calculation of trajectories of these two initial cracks is the first step in prediction of trajectories and rate of propagation of long cracks. This problem is important for analysis of durabi...

Development of macro and micro cracks on plastered walls and floors have been studied at different sites under site investigation whereby building inspections, construction history, engineering properties of soil and building surroundings assessment were conducted. We did revision of structural calculations and laboratory experiment to find out the source of cracks. Micro and macro cracks have ...

In the bridge inspection, the information of cracks is important to maintain a bridge. Therefore, automatic crack detection is highly desirable for efficiency and objectivity of crack assessment. However, in general, it is very difficult to detect cracks automatically from noisy concrete surfaces. In this paper, we propose a machine vision system for automatic inspection of bridges. The propose...

A defect sensing method based on electrical impedance spectroscopy is proposed to image cracks and reinforcing bars in concrete structures. The method utilizes the frequency-dependent behavior of thin insulating cracks: low-frequency electrical currents are blocked by insulating cracks, whereas high-frequency currents can pass through thin cracks to probe the conducting bars. From various frequ...

To improve the selectivity of closed cracks for objects other than cracks in ultrasonic imaging, we propose an extension of a novel imaging method, namely, subharmonic phased array for crack evaluation (SPACE) as well as another approach using the subtraction of responses at different external loads. By applying external static or dynamic loads to closed cracks, the contact state in the cracks ...