A New Acoustic Energy-Based Method to Estimate Pre-Loads on Cored Rocks

2018 ◽  
pp. 281-325
Author(s):  
Murat Karakus ◽  
Ashton Ingerson ◽  
William Thurlow ◽  
Michael Genockey ◽  
Jesse Jones
Keyword(s):  
Intersection Point ◽  
Acoustic Energy ◽  
Stress Axis ◽  
Irreversible Damage ◽  
Micro Cracks ◽  
Stress Curve ◽  
Sudden Release ◽  
The University ◽  
Straight Lines ◽  
Ae Signals

The Acoustic Emission (AE) due to the sudden release of energy from the micro-fracturing within the rock under loading has been used to estimate pre-load. Once the pre-load is exceeded an irreversible damage occurs at which AE signals significantly increase. This phenomenon known as Kaiser Effect (KE) can be recognised as an inflexion point in the cumulative AE hits versus stress curve. In order to determine the value of pre-load (sm) accurately, the curve may be approximated by two straight lines. The intersection point projected onto the stress axis indicates the pre-load. However, in some cases locating the point of inflexion is not easy. To overcome this problem we have developed a new method, The University of Adelaide Method (UoA), which use cumulative acoustic energy. Unlike existing methods, the UoA method emphasises the energy of each AE, the square term of the amplitude of each AE. As the axial pre-load is exceeded, the micro cracks become larger than the existing fractures and therefore energy released with new and larger cracks retain higher acoustic energy.

Experienced Rings around the Intersection Point in the Hering Illusion

1974 ◽  
Vol 38 (2) ◽  
pp. 639-646 ◽  
Author(s):  
Kristian Holt-Hansen
Keyword(s):  
Intersection Point ◽  
Parallel Lines ◽  
Straight Lines

When the stimulus was the Hering illusion, Ss experienced—besides oscillation of the parallel lines—different kinds of rings around the intersection point of the rays. These rings were most frequently a number of circles and less frequently ellipses. The colours of the rings contrasted with the colours of the Hering illusion. The fact that straight lines may condition the experience of rings (circles or ellipses) is juxtaposed with the results of another experiment, in which I demonstrated that a circle as stimulus conditioned the experience of straight lines as radii in the circle.

scholarly journals Finding the curved pathway of the large intestine for robot-aided colonoscopy

2021 ◽  
Vol 7 (2) ◽  
pp. 215-218
Author(s):  
Giuliano A. Giacoppo ◽  
Rebecca Mammel ◽  
Peter P. Pott
Keyword(s):  
Large Intestine ◽  
Color Space ◽  
Intersection Point ◽  
Binary Image ◽  
Measuring System ◽  
Nitinol Wire ◽  
The Wire ◽  
Straight Lines ◽  
Rgb Image ◽  
Wire Basket

Abstract To assist the insertion of a robot-aided endoscope during colonoscopy, a measuring system is required so that the endoscope tip can align automatically and thus find the curved pathway of the large intestine. To achieve this, a selfexpanding nitinol wire basket is used to sense the contour of the intestine. As the wire basket touches the wall, it is deflected towards the center of the intestine. The relative position of the wire basket within the camera image is captured, which describes the desired direction to follow the organ. To identify the wire basket in the image, the original RGB image stream is converted into the HSV (hue, saturation, value) color space. Thus, a binary image can be created, in which only the neongreen color portion of the wire basket is visible as a cross. The Hough Transformation is used to search for straight lines in the binary image. Once two lines are found, the intersection point can be calculated and thus its position in the image. The evaluation of the execution time of the algorithm on a live stream was 45 ± 31 ms on average. The algorithm robustly recognizes the wire basket even if it was not visible to the human eye in the original RGB image due to deficient lighting.

scholarly journals A Crack Characterization Method for Reinforced Concrete Beams Using an Acoustic Emission Technique

2020 ◽  
Vol 10 (21) ◽  
pp. 7918 ◽  
Author(s):  
Md Arafat Habib ◽  
Cheol Hong Kim ◽  
Jong-Myon Kim
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Crack Detection ◽  
Concrete Beams ◽  
Time History ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
K Nearest Neighbor ◽  
Micro Cracks ◽  
Ae Signals

This study aims at characterizing crack types for reinforced concrete beams through the use of acoustic emission burst (AEB) features. The study includes developing a solid crack assessment indicator (CAI) accompanied by a crack detection method using the k-nearest neighbor (k-NN) algorithm that can successfully distinguish among the normal condition, micro-cracks, and macro-cracks (fractures) of concrete beam test specimens. Reinforced concrete (RC) beams undergo a three-point bending test, from which acoustic emission (AE) signals are recorded for further processing. From the recorded AE signals, crucial AEB features like the rise time, decay time, peak amplitude, AE energy, AE counts, etc. are extracted. The Boruta-Mahalanobis system (BMS) is utilized to fuse these features to provide us with a comprehensive and reliable CAI. The noise from the CAI is removed using the cumulative sum (CUMSUM) algorithm, and the final CAI plot is used to classify the three different conditions: normal, micro-cracks, and fractures using k-NN. The proposed method not only for the first time uses the entire time history to create a reliable CAI, but it can meticulously distinguish between micro-cracks and fractures, which previous works failed to deal with in a precise manner. Results obtained from the experiments display that the CAI built upon AEB features and BMS can detect cracks occurring in early stages, along with the gradually increasing damage in the beams. It also soundly outperforms the existing method by achieving an accuracy (classification) of 99.61%, which is 17.61% higher than the previously conducted research.

Microstructure and Creep Behavior of a Directional Solidification Nickel-based Superalloy

2015 ◽  
Vol 34 (4) ◽  
Author(s):  
Ning Tian ◽  
Sugui Tian ◽  
Huichen Yu ◽  
Ying Li ◽  
Xianlin Meng
Keyword(s):  
Directional Solidification ◽  
Creep Behavior ◽  
Creep Property ◽  
Creep Damage ◽  
Stress Axis ◽  
Nickel Based Superalloy ◽  
Microstructure Observation ◽  
Micro Cracks ◽  
Initiation And Propagation ◽  
Property Measurement

AbstractBy means of creep property measurement and microstructure observation, an investigation has been made into microstructure and creep behavior of a directional solidification Ni-based superalloy at high temperatures. Results show that after full heat treatment, small cuboidal γ′ precipitates distribute in the dendrite regions, while coarser ones distribute in the inter-dendrite regions. In the primary stage of creep, the γ′ phase in alloy is transformed into the rafted structure along the direction vertical to stress axis, and then the creep of alloy enters the steady state stage. And dislocations slipping in the g matrix and climbing over the rafted γ′ phase are thought to be the deformation mechanism of the alloy during steady creep stage. At the latter stage of creep, the alternate slipping of dislocations may shear and twist the rafted γ′/γ phases, which promotes the initiation and propagation of the micro-cracks along the boundaries near the coarser rafted γ′ phase. And the bigger probability of the creep damage occurs in the grain boundaries along 45° angles relative to the stress axis due to them bearing relatively bigger shearing stress.

Deformation and Damage Features of a 4.5% Re Nickel-Based Single Crystal Superalloy during Creep at Medium Temperature

2014 ◽  
Vol 788 ◽  
pp. 459-465 ◽  
Author(s):  
De Long Shu ◽  
Su Gui Tian ◽  
Jing Wu ◽  
Zhong Ge Guo
Keyword(s):  
Single Crystal ◽  
Single Crystal Superalloy ◽  
Stress Axis ◽  
Fracture Mechanisms ◽  
Medium Temperature ◽  
Creep Properties ◽  
Microstructure Observation ◽  
Micro Cracks ◽  
Deformation And Fracture ◽  
Main Deformation

The deformation and damage behaviors of a 4.5% Re nickel-based single crystal superalloy during creep at medium temperature were conducted by means of creep properties measurement and microstructure observation in the present investigation. The results show that the creep life of the superalloy was measured to be 226h at 820MPa/820oC, displaying a better creep resistance. After the alloy crept up to fracture, the γ′ phase in the region near fracture was contorted and coarsened, which is attributed to the severe plastic deformation. In the latter stage of creep, the main/secondary slipping systems were alternately activated to twist the γ′ and γ phases, which promoted the initiation of the cracks along the interfaces of γ′ /γ phases. And the micro-cracks may be propagated both along the direction vertical to the stress axis and along the direction of slipping traces, which is thought to be the main deformation and fracture mechanisms of the alloy in the latter stage of the creep.

Study on Influences of Air Spring Failures on Ride Quality of High-Speed Railway Trains

2013 ◽  
Vol 420 ◽  
pp. 9-15 ◽  
Author(s):  
Dao Gong ◽  
Wen Jing Sun ◽  
Jin Song Zhou
Keyword(s):  
High Speed ◽  
Ride Quality ◽  
Railway Vehicle ◽  
Air Spring ◽  
High Speed Railway ◽  
Damping Characteristics ◽  
Secondary Support ◽  
Sudden Release ◽  
Straight Lines

A refined non-linear air spring model of railway vehicle model is established in this paper and the influences of different air spring failures on ride quality are studied. Results show that the orifice failure makes the air spring loses damping characteristics and deteriorates the vehicle ride quality; The failure of levelling valve has little influence on the ride quality when vehicle running on straight lines; The fracture of air spring diaphragm results in a sudden release of air, and car body secondary support disappears rapidly, excessive wheel unloading will happen and which can easily lead to derailment. In addition, the longer the leakage process, the less the influence on vehicle safety.

Dual Problems with Conics

2020 ◽  
Vol 8 (1) ◽  
pp. 15-24
Author(s):  
A. Girsh
Keyword(s):  
Euclidean Plane ◽  
Complex Geometry ◽  
Intersection Point ◽  
Dual Problems ◽  
Geometric Problems ◽  
Straight Line ◽  
Solution Methods ◽  
Method Of Solution ◽  
Straight Lines ◽  
Geometric Picture

The problem for construction of straight lines, which are tangent to conics, is among the dual problems for constructing the common elements of two conics. For example, the problem for construction of a chordal straight line (a common chord for two conics) ~ the problem for construction of an intersection point for two conics’ common tangents. In this paper a new property of polar lines has been presented, constructive connection between polar lines and chordal straight lines has been indicated, and a new way for construction of two conics’ common chords has been given, taking into account the computer graphics possibilities. The construction of imaginary tangent lines to conic, traced from conic’s interior point, as well as the construction of common imaginary tangent lines to two conics, of which one lies inside another partially or thoroughly is considered. As you know, dual problems with two conics can be solved by converting them into two circles, followed by a reverse transition from the circles to the original conics. This method of solution provided some clarity in understanding the solution result. The procedure for transition from two conics to two circles then became itself the subject of research. As and when the methods for solving geometric problems is improved, the problems themselves are become more complex. When assuming the participation of imaginary images in complex geometry, it is necessary to abstract more and more. In this case, the perception of the obtained result’s geometric picture is exposed to difficulties. In this regard, the solution methods’ correctness and imaginary images’ visualization are becoming relevant. The paper’s main results have been illustrated by the example of the same pair of conics: a parabola and a circle. Other pairs of affine different conics (ellipse and hyperbola) have been considered in the paper as well in order to demonstrate the general properties of conics, appearing in investigated operations. Has been used a model of complex figures, incorporating two superimposed planes: the Euclidean plane for real figures, and the pseudo-Euclidean plane for imaginary algebraic figures and their imaginary complements.

scholarly journals Role of Prior Cyclic Loading in the Initiation of Stress-Corrosion Cracks on Pipeline Steels Exposed to Near-Neutral pH Environment

2000 ◽  
Author(s):  
Sheng-Hui Wang ◽  
Weixing Chen ◽  
Tom Jack ◽  
Fraser King ◽  
Raymond R. Fessler ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Stress Corrosion ◽  
Steel Surface ◽  
Open Circuit ◽  
Stress Axis ◽  
Uniform Corrosion ◽  
Localized Deformation ◽  
Pipeline Steels ◽  
Neutral Ph ◽  
Micro Cracks

X-52 and X-80 pipeline steels have been used to study the effect of cyclic loading prior to corrosion exposure upon the initiation of stress-corrosion cracks in a near-neutral pH environment. To simulate realistic loading conditions, a cyclic loading scheme was constructed based on pressure fluctuation data collected on operating pipeline systems. It has been observed that cyclic loading either prior to corrosion exposure under static stress or during corrosion exposure enhances pitting corrosion and micro-cracking on the steel surface. These pits are seen to be aligned along scratches on the steel surface and to have coalesced to form micro-cracks at some locations. Some micro-cracks appeared not to have developed from pits, but were instead observed in a direction approximately 45 degree to stress axis. They are believed to have developed at locations where localized deformation such as persistent slip bands has occurred due to cyclic loading. In contrast to cyclic loading, no pits or micro-cracks were seen on the specimen that was subjected to static loading only. The pits and micro-cracks were only observed when the specimens were immersed under a cathodic potential of −790 mV SCE. At the open circuit potential only uniform corrosion occurred on the specimens whether they were cyclically or statically stressed.

Potential application of the Hogarth curves in the modern garment

2020 ◽  
Vol 32 (4) ◽  
pp. 511-522
Author(s):  
Xuyun Zhu ◽  
Wenjing Wen ◽  
Yun Luo ◽  
Yonglong Zhang ◽  
Di Sun
Keyword(s):  
Potential Application ◽  
Golden Ratio ◽  
Intersection Point ◽  
Design System ◽  
Plant Design ◽  
Pattern Design ◽  
Content Type ◽  
Potential Applications ◽  
Novel Method ◽  
Straight Lines

Purpose The purpose of this paper is to develop a novel method for establishing the mathematical link between the restored Hogarth curve and the golden ratio, and to advance the potential application of the Hogarth curves in standardization of the garment pattern design by using this method. Design/methodology/approach The Hogarth curve was fully restored by using the plant design system (PDS) software package and divided the restored curve into two fragments based on the intersection point between the curve and the straight line joining the curve endpoints. The ratios between two fragments of curves and straight lines were calculated and compared with the golden ratio, respectively, which was set as a normalized value. The potential application of the restored Hogarth curves in the normalization of the garment pattern design was therefore studied by using the standard mannequins. Findings The ratio in the most beautiful curve, i.e., the fourth Hogarth curve, was found to be infinitely approaching to the golden ratio. Furthermore, the incorporation of the Hogarth curves into the garment pattern design demonstrated that the fourth Hogarth curve was the most aesthetic line. Originality/value This work offered a novel method for bridging the gaps between arts and maths, i.e., the mathematical relation between the Hogarth curves and the golden ratio. Such a method will provide the protocol to promote the potential applications of the Hogarth curves in the garment pattern design and the human body decoration.

scholarly journals The Scanning Electron Microscope As A Precision Instrument

1996 ◽  
Vol 4 (6) ◽  
pp. 30-34
Author(s):  
Douglas Hansen
Keyword(s):  
Diffraction Gratings ◽  
Stray Field ◽  
X Ray Diffraction ◽  
Precision Instrument ◽  
X Ray ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
The University ◽  
Straight Lines ◽  
Scanning Electron

I began using scanning electron microscopes to solve problems encountered in the fabrication of x-ray diffraction gratings. Since these diffraction gratings consist of very regular lines and spaces, and produce high contrast images from the SEM. my microscopy work often points out problems with the microscope.One time, for example, I went to the university SEM lab I often use, and was advised that the microscope was down that day due to major field problems. This lab often had problems with stray fields for reasons no one could explain. Usually I was the only one to complain about stray field distortions since they are most obvious when imaging straight lines at high magnification, but on this occasion, the problem was serious and obvious to all.The microscope had just been serviced and as the lens coils had been replaced, they were expected to be the cause. The service technician was called in and determined that neither the coils nor the microscope electronics were the problem.

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