Journal articles: 'Defect dimensions'

1

Kumaresh, Sakthi. "Defect Prevention Based on 5 Dimensions of Defect Origin." International Journal of Software Engineering & Applications 3, no. 4 (July 31, 2012): 87–98. http://dx.doi.org/10.5121/ijsea.2012.3407.

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KUMAR, V. SUNIL, BISWANATH LAYEK, AJIT M. SRIVASTAVA, SOMA SANYAL, and VIVEK K. TIWARI. "SKYRMION FORMATION IN 1+1 DIMENSIONS WITH CHEMICAL POTENTIAL." International Journal of Modern Physics A 21, no. 06 (March 10, 2006): 1199–219. http://dx.doi.org/10.1142/s0217751x06029508.

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Formation of topological objects during phase transitions has been discussed extensively in literature. In all these discussions, defects and antidefects form with equal probabilities. In contrast, many physical situations, such as formation of baryons in relativistic heavy-ion collisions at present energies, flux tube formation in superconductors in the presence of external magnetic field, and formation of superfluid vortices in a rotating vessel, require a mechanism which can bias (say) defects over antidefects. Such a bias can crucially affect defect–antidefect correlations, apart from its effects on defect density. In this paper we initiate an investigation for the basic mechanism of biased formation of defects. For Skyrmions in 1+1 dimensions, we show that incorporation of a chemical potential term in the effective potential leads to a domain structure where order parameter is spatially varying. We show that this leads to biased formation of Skyrmions.

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Li, Bao Long, Li Jun Zhou, and Jian Gao Guo. "Influence of Defects on Elastic Buckling Properties of Single-Layered Graphene Sheets." Key Engineering Materials 636 (December 2014): 11–14. http://dx.doi.org/10.4028/www.scientific.net/kem.636.11.

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Molecular structural mechanics based finite element method has been applied to study the effects of two types of Stone-Wales (SW) defects and vacancy defect on elastic buckling properties of single-layered graphene sheets (SLGSs). The defect effect factors of critical buckling stresses are calculated for the defective SLGSs with different chirality and geometrical dimensions. It is proved that defect effect factors are size-dependent and chirality-dependent. The results show that the vacancy defects will always weaken the SLGSs’ stability, and two types of SW defects have different effects on zigzag and armchair SLGSs. What’s more, the positions of defects also have remarkable influence on the critical buckling stress of SLGSs.

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Ye, Bo, Jun Dong, Gefei Qiu, Siqi Li, Fang Zeng, Tanghua Yang, Biao Bai, and Zhangzhou He. "Eddy Current Inversion Models for Estimating Dimensions of Defects in Multilayered Structures." Mathematical Problems in Engineering 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/649608.

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In eddy current nondestructive evaluation, one of the principal challenges is to determine the dimensions of defects in multilayered structures from the measured signals. It is a typical inverse problem which is generally considered to be nonlinear and ill-posed. In the paper, two effective approaches have been proposed to estimate the defect dimensions. The first one is a partial least squares (PLS) regression method. The second one is a kernel partial least squares (KPLS) regression method. The experimental research is carried out. In experiments, the eddy current signals responding to magnetic field changes are detected by a giant magnetoresistive (GMR) sensor and preprocessed for noise elimination using a wavelet packet analysis (WPA) method. Then, the proposed two approaches are used to construct the inversion models of defect dimension estimation. Finally, the estimation results are analyzed. The performance comparison between the proposed two approaches and the artificial neural network (ANN) method is presented. The comparison results demonstrate the feasibility and validity of the proposed two methods. Between them, the KPLS regression method gives a better prediction performance than the PLS regression method at present.

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Jin, Xian Yu, Nan Guo Jin, and Xiang Lin Gu. "Damage Analysis of Waterproof Layer in Composite Tunnel Lining Based on Theory of Plate with Large Deflection." Key Engineering Materials 400-402 (October 2008): 245–50. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.245.

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: In order to analyze the cause of water leakage in highway tunnels, the damage property of waterproof board in composite tunnel lining with concrete matrix defects under hydraulic pressure was studied using Galerkin method for plates with large deflection. The deflection, stress and strain of waterproof boards were calculated in the conditions of rectangular and elliptic boundary due to concrete matrix defects. First strength theory was used to determine the critical load of the board and the critical depth of the defect. Investigation results showed that the maximum principal stress generates in the middle of longer side in the rectangular boundary condition and in the center in the elliptic boundary condition, the failure of the waterproof board under certain hydraulic pressure is related with the dimensions of concrete matrix defects and the dimension of the concrete matrix defect needs to be controlled in the design and construction of waterproof layer for tunnels.

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Zheng, Gangfeng, Bolin Wu, Ze Li, Songfeng Liu, Hao Dong, and Haotian Zhang. "Research on 3D Defect Reconstruction in Plate with Phased Array Ultrasonic Test (PAUT)." Journal of Physics: Conference Series 2171, no. 1 (January 1, 2022): 012017. http://dx.doi.org/10.1088/1742-6596/2171/1/012017.

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Abstract In order to clarify the distribution and shape information of the defects inside the workpiece, it has become a new industrial testing requirement to display the defects more intuitively in three dimensions(3D). In this paper, by introducing 3D volume rendering method, the expansion of PAUT from 2D to 3D is realized. The method is used to reconstruct specific “gu-shaped [[CHECK_DOUBLEQUOT_ENT]] (“Gu” is the Pinyin in Chinese characters, and at the same time, “Gu” is the shape of the defect in the plate discussed in the paper.) defects, and the results of reconstruction are compared with actual defects. By using ultrasonic phased array focusing to detect defect C-scan images of different depths, the collected C-scan images were preprocessed and reconstructed according to the defect contour by volume rendering. The results show that the defect morphology with different depths can be well obtained by focused detection, and the reconstruction effect is good, which is consistent with the actual defect.

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Kim, Sang-Kon. "Computational Study of Extreme Ultraviolet Vote-Taking Lithography for Defect Repair." Journal of Nanoscience and Nanotechnology 20, no. 8 (August 1, 2020): 4994–97. http://dx.doi.org/10.1166/jnn.2020.17822.

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Extreme ultraviolet (EUV) lithography is a prospective technology for the fabrication of integrated chips with critical dimensions (CDs) under 10-nm. However, since chips with similar CDs have similar defect sizes, one of the most critical problems in extreme ultraviolet lithography (EUVL) is mask defect and repair. Defects cause local areas of undesired absorption, reflectivity, or phase change, which ultimately lead to imperfections in the printed image. For example, phase defects may cause substantial changes in image anomalies with different focuses. In this paper, the results of EUV vote-taking lithography are calculated and compared with other repair methods using the scattering matrix (S-matrix) method. Vote-taking lithography with the assumed perfect defect-free masks (N = 4) can maximize 90% and 91% repair improvements at pit defect and dump defect, respectively.

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Ellis, John, N. E. Mavromatos, and D. V. Nanopoulos. "M-Theory from Worldsheet Defects in Liouville String." Modern Physics Letters A 12, no. 36 (November 30, 1997): 2813–27. http://dx.doi.org/10.1142/s0217732397002946.

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We have argued previously that black holes may be represented in a D-brane approach by monopole and vortex defects in a sine–Gordon field theory model of Liouville dynamics on the worldsheet. Supersymmetrizing this sine–Gordon system, we find critical behavior in 11 dimensions, due to defect condensation which we interpret as the worldsheet analog of D-brane condensation around an extra space–time dimension in M-theory. This supersymmetric description of Liouville dynamics has a natural embedding within a 12-dimensional framework suggestive of F-theory.

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Phanitwong, Wiriyakorn, and Sutasn Thipprakmas. "Finite element analysis of piping defect formation in the sheet-extrusion process." International Journal of Modeling, Simulation, and Scientific Computing 06, no. 01 (March 2015): 1550010. http://dx.doi.org/10.1142/s1793962315500105.

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The pressing process, as compared to the machining process, makes good utilization of work piece material and shortens the production time, and as such it is increasingly used for production of complex shaped parts. A particular type of pressing is sheet-extrusion which controls the flow of material into special punch and die sets to produce an extruded shape. However, some particularly complex shaped parts cannot be made by sheet-extrusion due to the formation of piping defects. In this study, the finite element method (FEM) was used to investigate the formation of piping defects. In addition, the relationship between the characteristic dimensions of the extruded shape and the piping defect was also examined. Laboratory pressing experiments were performed to validate the accuracy of the FEM simulation results. Based on the stress distribution and velocity profiles within the extruded work piece, the relationship between the extruded shape and the piping defect was clearly identified. Furthermore, the FEM simulation results showed good agreement with the experimental results with regards to the dimensions of the extruded shape and the piping defect.

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Jo, Soo-Ho, and Byeng D. Youn. "A Phononic Crystal with Differently Configured Double Defects for Broadband Elastic Wave Energy Localization and Harvesting." Crystals 11, no. 6 (June 5, 2021): 643. http://dx.doi.org/10.3390/cryst11060643.

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Several previous studies have been dedicated to incorporating double defect modes of a phononic crystal (PnC) into piezoelectric energy harvesting (PEH) systems to broaden the bandwidth. However, these prior studies are limited to examining an identical configuration of the double defects. Therefore, this paper aims to propose a new design concept for PnCs that examines differently configured double defects for broadband elastic wave energy localization and harvesting. For example, a square-pillar-type unit cell is considered and a defect is considered to be a structure where one piezoelectric patch is bonded to a host square lattice in the absence of a pillar. When the double defects introduced in a PnC are sufficiently distant from each other to implement decoupling behaviors, each defect oscillates like a single independent defect. Here, by differentiating the geometric dimensions of two piezoelectric patches, the defects’ dissimilar equivalent inertia and stiffness contribute to individually manipulating defect bands that correspond to each defect. Hence, with adequately designed piezoelectric patches that consider both the piezoelectric effects on shift patterns of defect bands and the characteristics for the output electric power obtained from a single-defect case, we can successfully localize and harvest the elastic wave energy transferred in broadband frequencies.

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Xu, Ke, Peng Zhou, and Chao Lin Yang. "Application of Fractal Dimension Feature to Recognition of Surface Defects on Hot-Rolled Strips." Applied Mechanics and Materials 152-154 (January 2012): 526–30. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.526.

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Because steel strips are covered with scales and water during hot-rolling, it is difficult to recognize the defects from images of hot-rolled strips through conventional methods. Principles and characteristics of fractal dimensions were studied, and computation of the fractal dimensions of the defect images with Peleg Covered Carpet is presented. Fractal dimensions of piecewise linearly transformed and smoothed images were used as features for classification of defects. These features were inputted to train the AdaBoost classifier. Experiments with samples of pimples, shells and scales from a real surface inspection system of hot-rolled strips showed that it is effective to recognized scales from other defects, and the total classification rate of this method is higher than 90%.

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Xu, Da-Chuan, Huai-Shu Hou, Cai-Xia Liu, and Chao-Fei Jiao. "Defect type identification of thin-walled stainless steel seamless pipe based on eddy current testing." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 12 (December 1, 2021): 697–703. http://dx.doi.org/10.1784/insi.2021.63.12.697.

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Aimed at eddy current detection of defects in thin-walled stainless steel seamless pipes, an effective detection method for identifying defect types is proposed. First, the empirical mode decomposition (EMD) method is used to process the collected eddy current signals and obtain the principal intrinsic mode function (IMF) components of different defects. The Hilbert-Huang transform (HHT) is used to extract the frequency-domain features of the principal IMF components, which are combined with the time-domain features to form an effective defect feature vector. Then, principal component analysis (PCA) is used to reduce the dimensions of the defect feature vector and the redundant information is removed to obtain the principal component vector of the defect. Finally, two radial basis function (RBF) neural networks are used to identify and classify the defect types and three error evaluation indicators are selected to evaluate the performance of the classification network models.

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Nagata, Shoichiro, Takemi Sakamoto, and Masato Enokizono. "Quantitative Defect Detection inside Metal Casting Specimens by Means of MFES." Materials Science Forum 792 (August 2014): 104–9. http://dx.doi.org/10.4028/www.scientific.net/msf.792.104.

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An NDE measurement for internal defects of metal casting products is presented. The internal defects are often made in the manufacturing process of metal casting. From the view point of non-destructive evaluation (NDE), it is very difficult to make artificial defects that simulate actual internal defects. Therefore, we prepared a lot of metal casting samples that may include defects, and investigated the relation between the defect dimensions and the spectrogram that were generated by Multi-Frequency Excitation and Spectrogram Method (MFES).

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Zhao, Chenxi, Zhou Li, Tianjiao Fan, Chong Xiao, and Yi Xie. "Defects Engineering with Multiple Dimensions in Thermoelectric Materials." Research 2020 (May 22, 2020): 1–23. http://dx.doi.org/10.34133/2020/9652749.

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Going through decades of development, great progress in both theory and experiment has been achieved in thermoelectric materials. With the growing enhancement in thermoelectric performance, it is also companied with the complexation of defects induced in the materials. 0D point defects, 1D linear defects, 2D planar defects, and 3D bulk defects have all been induced in thermoelectric materials for the optimization of thermoelectric performance. Considering the distinct characteristics of each type of defects, in-depth understanding of their roles in the thermoelectric transport process is of vital importance. In this paper, we classify and summarize the defect-related physical effects on both band structure and transport behavior of carriers and phonons when inducing different types of defects. Recent achievements in experimental characterization and theoretical simulation of defects are also summarized for accurately determining the type of defects serving for the design of thermoelectric materials. Finally, based on the current theoretical and experimental achievements, strategies engaged with multiple dimensional defects are reviewed for thermoelectric performance optimization.

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15

Ignatovich, S. R. "Distribution of defect dimensions in loading solids." Strength of Materials 22, no. 9 (September 1990): 1295–301. http://dx.doi.org/10.1007/bf00770970.

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CHACALTANA, OSCAR, JACQUES DISTLER, and YUJI TACHIKAWA. "NILPOTENT ORBITS AND CODIMENSION-2 DEFECTS OF 6d${\mathcal N} = (2, 0)$ THEORIES." International Journal of Modern Physics A 28, no. 03n04 (February 10, 2013): 1340006. http://dx.doi.org/10.1142/s0217751x1340006x.

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We study the local properties of a class of codimension-2 defects of the 6d [Formula: see text] theories of type J = A, D, E labeled by nilpotent orbits of a Lie algebra [Formula: see text], where [Formula: see text] is determined by J and the outer-automorphism twist around the defect. This class is a natural generalization of the defects of the six-dimensional (6d) theory of type SU (N) labeled by a Young diagram with N boxes. For any of these defects, we determine its contribution to the dimension of the Higgs branch, to the Coulomb branch operators and their scaling dimensions, to the four-dimensional (4d) central charges a and c and to the flavor central charge k.

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Xu, Chunguang, Joseph L. Rose, and Xiang Zhao. "Detection Principle of Shape and Orientation of Corrosive Defects Using Lamb Waves." Journal of Robotics and Mechatronics 21, no. 5 (October 20, 2009): 568–73. http://dx.doi.org/10.20965/jrm.2009.p0568.

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The shape and orientation of corrosive defects are critical in the evaluation of the reliability and durability of plate-like structures. And Lamb wave is considered as an effective tool for inspections of this kind corrosive plates. In this paper, the shape and orientation of plane defects are detected and presented using a circular transducer array with Lamb wave tomography approach. Here, considering a special shape defect with two-dimensions elliptical contour in the plate, the various ratios for both defect shape and orientation, individually representing different classifications of defects, is identified and investigated using Lamb wave tomography approach. And the validity of this approach has been proved through simulation experiments.

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Salzmann, Gian M., Philipp Niemeyer, Alfred Hochrein, Martin J. Stoddart, and Peter Angele. "Articular Cartilage Repair of the Knee in Children and Adolescents." Orthopaedic Journal of Sports Medicine 6, no. 3 (March 1, 2018): 232596711876019. http://dx.doi.org/10.1177/2325967118760190.

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Articular cartilage predominantly serves a biomechanical function, which begins in utero and further develops during growth and locomotion. With regard to its 2-tissue structure (chondrocytes and matrix), the regenerative potential of hyaline cartilage defects is limited. Children and adolescents are increasingly suffering from articular cartilage and osteochondral deficiencies. Traumatic incidents often result in damage to the joint surfaces, while repetitive microtrauma may cause osteochondritis dissecans. When compared with their adult counterparts, children and adolescents have a greater capacity to regenerate articular cartilage defects. Even so, articular cartilage injuries in this age group may predispose them to premature osteoarthritis. Consequently, surgery is indicated in young patients when conservative measures fail. The operative techniques for articular cartilage injuries traditionally performed in adults may be performed in children, although an individualized approach must be tailored according to patient and defect characteristics. Clear guidelines for defect dimension–associated techniques have not been reported. Knee joint dimensions must be considered and correlated with respect to the cartilage defect size. Particular attention must be given to the subchondral bone, which is frequently affected in children and adolescents. Articular cartilage repair techniques appear to be safe in this cohort of patients, and no differences in complication rates have been reported when compared with adult patients. Particularly, autologous chondrocyte implantation has good biological potential, especially for large-diameter joint surface defects.

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Widyawati, Fauzi, and Lino Marano. "IDENTIFIKASI CACAT LASAN FCAW PADA FONDASI MESIN KAPAL MENGGUNAKAN METODE ULTRASONIC TESTING." Jurnal TAMBORA 5, no. 2 (July 21, 2021): 53–58. http://dx.doi.org/10.36761/jt.v5i2.1124.

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Ultrasonic testing is one of the non-destructive inspection methods for welding results. The ultrasonic testing method has several advantages, namely it can be used to analyze the position of the defect in the object, both the depth of the defect and the dimensions of the defect, and it is an environmentally friendly method. Physical defects that are in solid objects of course cannot be known from direct vision so it is necessary to carry out an inspection of an object to see whether or not there are defects that occur in solid objects. Ultrasonic testing of the results of FCAW welding on the foundation of the ship's engine. FCAW welding is applied to the foundation with two types of welding positions, namely the overhead position coded P1 and the horizontal position coded P2. The test was carried out using a wave frequency of 4 MHz and using a 0° probe for analysis of defects in the area around the weld metal and a 70° probe for analysis of the weld metal. The tests were carried out using the ASME section V and ASTM E164 standards as the standard for determining defects. The test results at the P1 welding position found two types of defects, namely incomplete fusion defects with five welding points with the longest defect length of 40mm and porosity defects with two points with the longest defect length of 30mm. While the results of ultrasonic testing at the P2 welding position found two types of defects, namely slag inclusion defects with a defect length of 35mm and incomplete penetration defects with a defect length of 20 mm. The conclusion of ultrasonic testing is that the difference in welding positions is that the welding position greatly affects the quality of the welding results. The defects resulting from the welding position also vary.

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Hassine, N., S. Chatti, M. Ben Slama, and L. Kolsi. "Sensitivity of Melt Pool Dimensions and Keyhole to Laser Beam Diameter." Annals of Dunarea de Jos University of Galati Fascicle XII Welding Equipment and Technology 32 (December 31, 2021): 30–36. http://dx.doi.org/10.35219/awet.2021.04.

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The laser powder bed fusion process has witnessed a huge interest in recent years since it has the potential to produce challenging shapes in a broad range of applications. The process parameters have a considerable effect on melt pool size and on the development of defect porosity. This paper predicts numerically the effect of a large range of laser beam diameters on melt pool dimensions and on the occurrence of porosity defects such as keyhole. A series of single beads of Inconel IN625 was made using various combinations of beam diameters, scan speeds, and laser powers. The use of a large diameter was more suitable rather than a small diameter as it ensures a large and shallow heat affected zone, thus decreasing the development of the keyhole defect. Our numerical results correlate satisfactorily with experimental finding from literature.

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Nowak, Paweł, Roman Szewczyk, and Anna Ostaszewska-Liżewska. "Inverse Transformation in Eddy Current Tomography with Continuous Optimization of Reference Defect Parameters." Materials 14, no. 17 (August 24, 2021): 4778. http://dx.doi.org/10.3390/ma14174778.

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This paper presents a methodology of inverse tomography transformation in eddy current tomography with the use of continuous optimization of reference defect parameters. Ferromagnetic steel samples with rectangular air inclusion defects of known dimensions were prepared and measured using an eddy current tomography setup. FEM-based (Finite Element Method based) forward tomography transformation was developed and utilized in inverse tomography transformation. The presented method of inverse tomography transformation is based on the continuous optimization of parameters that can describe the sample, such as the diameter and dimensions of the reference defect. The obtained results of inverse tomography transformation were in high accordance with the real parameters of the samples. Additionally, the presented method had acceptable repeatability. The obtained values of the sample parameters fit within the range of expanded uncertainty when compared to the real parameters of the sample.

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Zbrowski, Andrzej, and Wojciech Jóźwik. "Influence of the Gap between Measuring Head and Tested Object on the Results of an Eddy Current Test Method." Solid State Phenomena 223 (November 2014): 246–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.223.246.

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The article presents the influence of the distance between a measuring head and a tested object on the results of eddy current defectoscopy test. The tests were conducted on the two inner rings of a tapered roller bearing where the test defects were performed. A one-millimetre hole corresponded to the surface defect. Internal blind holes in the shape of a rectangle corresponded to a subsurface defect. The research was performed with the use of a SSEC III PC defectoscope connected to a mobile PC. The measuring device is part of the system for the automatic quality control of bearing rings. The test was conducted for a slit having following dimensions: 0.1, 0.2, 0.3, 0.4, and 0.5 mm. The obtained characteristics are the composition of the pulse caused by the detected defect and the sine wave caused by the axial runout of the tested bearing ring. The correlation between the slit size and the value of the signal of the defect and the sine wave caused by axial runout of the tested ring was observed. The concept of “a coefficient of defect detection” was introduced. The described coefficient is a quotient of the value of the defect signal and the peak-to-peak value of the sine wave caused by axial runout of the tested bearing ring. The increase in the dimensions of the slit from 0.1 to 0.5 mm causes a 35 - 50% decrease in the coefficient of defect detection, depending on the test defect. A handle was designed to ensure a constant pressure of measuring head on the tested surface was proposed.

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Laptev, Roman S., Andrey M. Lider, Yuriy S. Bordulev, Viktor N. Kudiiarov, Georgy V. Garanin, Wei Wang, and Pavel V. Kuznetsov. "Investigation of Defects in Hydrogen-Saturated Titanium by Means of Positron Annihilation Techniques." Defect and Diffusion Forum 365 (July 2015): 232–36. http://dx.doi.org/10.4028/www.scientific.net/ddf.365.232.

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This paper presents the results of a defect structure investigation in commercially pure titanium alloy after hydrogen charging in a gaseous atmosphere at the temperature of 873 K up to the concentration of 5.1 at. %. Structure of samples was studied by positron lifetime, Doppler broadening and X-ray diffraction spectrometry. Several processes, corresponding to the different ranges of hydrogen concentrations were revealed. It was shown that hydrogen, penetrating in the material, expands its crystal lattice, initiates formation of vacancy-like defects of different dimensions and reacts with the last ones, forming the defect-hydrogen complexes.

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Scruby, C. B., K. A. Stacey, and G. R. Baldwin. "Defect characterisation in three dimensions by acoustic emission." Journal of Physics D: Applied Physics 19, no. 9 (September 14, 1986): 1597–612. http://dx.doi.org/10.1088/0022-3727/19/9/006.

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Shayan, Ramin, Aoife Margaret Hurley, Derek Neoh, Dr Stephen Flood, and Michael Weymouth. "Reconstructing ‘dual-defect’ pressure sores in spinal patients." Australasian Journal of Plastic Surgery 2, no. 2 (September 28, 2019): 21–27. http://dx.doi.org/10.34239/ajops.v2n2.107.

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Background: Recurrent pressure sores and unstable scars over the bony prominences of the greater trochanter and ischium are a troublesome sequela of spinal injury. A reliable reconstruction is needed for patients with ‘dual-defect’ pressure sores in these locations. We modified the pedicled anterolateral thigh (ALT) flap to fit the reconstructive requirements of ‘dual-defect’ pressure sores.Methods: Eleven consecutive patients with concurrent pressure sores (> grade III) or unstable scar in one of the ‘dual-defect’ areas and an active pressure sore in the other were identified from the Victorian state tertiary referral centre for spinal injuries. We describe the technique and clinical experience of pedicled ALT flaps for reconstruction of ‘dual-defect’ pressure sores in this patient cohort. Preoperative status and minor and major postoperative complications were recorded. Results: Eleven consecutive pedicled myocutaneous ALT flaps were performed for reconstruction of ‘dual-defect’ pressure sores. Several key variations in the anatomical landmarks and the intra-operative flap raise technique that are integral to the use of the ALT flap for this application are described herein. The average dimensions of the cutaneous pressure sore defects were 6 x 4.9 cm (greater trochanter) and 8.2 x 6.7 cm (ischial). The average dimensions of the cutaneous paddle of the flaps raised were 27.3 x 8.4 cm. Two postoperative complications necessitated return to theatre but no incidences of flap loss were recorded. Conclusions: The modified pedicled myocutaneous ALT provides a robust reconstructive solution for resurfacing ‘dual-defect’ pressure sores in spinal patients. Further recommendations for future technical adaptations are made.

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Touil, D. R., A. Daas, B. Helifa, A. C. Lahrech, and L. Ibn Khaldoun. "Simple Giant Magnetoresistance Probe Based Eddy Current System of Defect Characterization for Non-Destructive Testing." Advanced Electromagnetics 11, no. 2 (May 11, 2022): 43–48. http://dx.doi.org/10.7716/aem.v11i2.1910.

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The purpose of this paper is to present a new giant magnetoresistance (GMR) sensor, in eddy current testing technique for surface defect detection, in conducting materials, we show that the GMR based eddy currents probe is more sensitive than the inductive probe. A flat coil mounted on ferrite pot used to produce an alternate magnetic field, which gives rise to eddy currents in the material under test. Aluminum plates use with defects have nominal depths, widths, and lengths. The defects scanned with the sensing axis perpendicular to the defect length. Two parameters extracted from the GMR output voltage signal obtained, and a simple correlation between the defect’s dimensions and the GMR output voltage proposed.

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Киреев and Andrey Kireev. "Experimental Research of Flaw Detection Technique at Manual Ultrasonic Testing of Railway Rolling Stock Elements." NDT World 18, no. 4 (December 16, 2015): 72–75. http://dx.doi.org/10.12737/15939.

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Introduction. The work aim was to carry out experimental studies of dual-frequency method reliability for defect type determination at manual ultrasonic testing of railway rolling stock elements. Method. The method of discontinuity type determination includes: measuring amplitude characteristics of echo signals from the detected defect on the frequency of 2.5 and 5.0 MHz; calculation a defect form-factor; comparing the form-factor with the certain limit values, one of which corresponds to a planar defect and the other corresponds to a volume defect. The defect is considered planar/volume, if its form-factor differs from the appropriate limit value by no more than 30%. The method gives an opportunity to determine types for both point and extensive defects. For the experiment a sample was manufactured, in which various artificial reflectors of different types and dimensions were made. The type of each reflector was determined with dual-frequency method. The relative error and reliability of type determination were calculated. Results. Experimental studies have shown that reliability of defect type determination with dual-frequency method is quite high. The average accuracy of point defect determination has been 97,389%; extensive defect determination has been 93,588%.

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Markov, Oleg E., Natalia A. Rudenko, Igor A. Grachov, Aleksandar Ristovski, and Vladimir Radojičić. "Improvement of Plate’s Shape for Ingots Upsetting." Applied Mechanics and Materials 806 (November 2015): 141–50. http://dx.doi.org/10.4028/www.scientific.net/amm.806.141.

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A stress-strain state and a resize of an axial defect during upsetting have been investigated in the article. Theoretical research based on a FEM has been conducted. The upsetting of cylindrical steel workpieces which had the axial defect equal to 10 % of the workpiece diameter has been simulated. Upsetting has been carried out by flat, concave-conical and convex plates (solid or with hole). The result of the studies showed that the main influence on the workpiece shape had a ratio of dimensions. The maximal closure of the axial defect provides upsetting by concave-conical solid plates. Upsetting by flat plates does not provide the closure of axial defects. Convex plates provide the uniform stress-strain state along the workpiece cross section. The hole in the plates increases the non-uniformity of strain distribution and also does not provide the axial defects closure.

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Lei, Linjian, Shengli Sun, Yue Zhang, Huikai Liu, and Hui Xie. "Segmented Embedded Rapid Defect Detection Method for Bearing Surface Defects." Machines 9, no. 2 (February 14, 2021): 40. http://dx.doi.org/10.3390/machines9020040.

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The rapid development of machine vision has prompted the continuous emergence of new detection systems and algorithms in surface defect detection. However, most of the existing methods establish their systems with few comparisons and verifications, and the methods described still have various problems. Thus, an original defect detection method: Segmented Embedded Rapid Defect Detection Method for Surface Defects (SERDD) is proposed in this paper. This method realizes the two-way fusion of image processing and defect detection, which can efficiently and accurately detect surface defects such as depression, scratches, notches, oil, shallow characters, abnormal dimensions, etc. Besides, the character recognition method based on Spatial Pyramid Character Proportion Matching (SPCPM) is used to identify the engraved characters on the bearing dust cover. Moreover, the problem of characters being cut in coordinate transformation is solved through Image Self-Stitching-and-Cropping (ISSC). This paper adopts adequate real image data to verify and compare the methods and proves the effectiveness and advancement through detection accuracy, missing alarm rate, and false alarm rate. This method can provide machine vision technical support for bearing surface defect detection in its real sense.

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Ismagilov, I. R., R. I. Kalimullin, and A. N. Borisov. "Increasing the laser-acoustic method efficiency for testing metal products by using 3D visualization." E3S Web of Conferences 124 (2019): 03010. http://dx.doi.org/10.1051/e3sconf/201912403010.

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The article proposes a solution to the problem of increasing the efficiency of the laser-acoustic method of non-destructive testing. An approach to increasing the probability of detecting surface defects of microscopic dimensions in metals is considered. Due to the increased accuracy of determining defect parameters, the detail of 3D visualization of testing results was improved.

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Madi, Marwa, Osama Zakaria, and Shohei Kasugai. "Coated vs Uncoated Implants: Bone Defect Configurations After Progressive Peri-implantitis in Dogs." Journal of Oral Implantology 40, no. 6 (December 1, 2014): 661–69. http://dx.doi.org/10.1563/aaid-joi-d-12-00089.

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In this study, hydroxyapatite coated vs uncoated implants were used to evaluate the type and dimensions of bone defects after progressive peri-implantitis in dogs. Thirty-two dental implants with 4 different surfaces—machined (M), sandblasted acid-etched (SA), 1-μm thin sputter hydroxyapatite (HA)-coated (S), and plasma-sprayed HA-coated (P)—were inserted into the mandibles of 4 beagle dogs after extracting all mandibular premolars. Experimental peri-implantitis was induced after 3 months using ligature to allow for plaque accumulation. After 4 months, ligatures were removed and plaque accumulation continued for 5 months (progression period). The open flap surgery demonstrated 3 patterns of peri-implantitis bone defect: (1) Class I defect: represented as circumferential intra-alveolar bone loss; (2) Class II defect: circumferential intra-alveolar defect with supra-alveolar bone loss exposing the implant surface; and (3) Class III defect: represented as circumferential intra-alveolar defect with supra-alveolar bone loss and buccal dehiscence. Class I was the most frequent (62.5%) defect pattern around implant types M, SA, and S; while implant type-P showed a recurring majority of Class II (62.5%). Comparison among the 4 implant groups revealed a significant defect width (DW) in implant type-P relative to other types (P < 0.01). However, no statistically significant differences were noted for defect depth (DD) (P > 0.05). We concluded that the shape and size of peri-implantitis bone defects were influenced by the type and thickness of the HA coat together with the quantity of the available peri-implant bone. Plasma-sprayed HA-coated implants showed larger peri-implant defects than did thin sputter HA-coated implants.

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Ussia, Gian Paolo, Tarek S. Momenah, Phillip Ursell, Mike M. Brook, Philip Moore, Francesco De Luca, and Norman H. Silverman. "Evaluation of the morphology of the oval fossa for placement of devices." Cardiology in the Young 10, no. 5 (September 2000): 502–9. http://dx.doi.org/10.1017/s1047951100008192.

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AbstractObjectivesFirst, to examine the morphology of heart specimens with defects of the oval fossa so as to define the factors that facilitate appropriate selection of the size of devices used for inteventional closure. Second, to examine the relationship between morphology and transthoracic and transesophageal echocardiography.BackgroundThe success of transcatheter closure is influenced by the variable morphology of deficiencies with the oval fossa, and of the relationship of the fossa itself to adjacent structures. More appropriate selection could reduce the incidence of failures.MethodsFrom over 100 specimens in the cardiac registry at the University of California, San Francisco, we judged 16 hearts with atrial septal defects within the oval fossa, either in isolation or associated with other cardiac malformation, to be suitable for this study. We measured the dimensions of the defect and the surrounding rims of the fossa. All values were normalized to the diameter of the aortic root.ResultsA fenestrated defect was present in 9 specimens (56%). The shape defect itself was oval in all specimens, with a ratio of major to minor axes of 1.70 ± 0.63– The major axis took one of three main directions with respect to the vertical plane: in 11 specimens (69%) it was at horizontal; in 3 (19%) it was at oblique at an angle of 45 degrees; and in 2 (12%) it was vertical. Discordance was noted in some hearts between the major axis of the defect and that of the oval fossa. Structures closest to the rim of the fossa were the aortic mound, the coronary sinus, and the hinge point of the aortic leaflet of the mitral valve.ConclusionsExtrapolating from these specimens permitted identification of the major and minor axes of the atrial septal defect by transthoracic and transesophageal echocardiography. Our study has identified landmarks and dimensions that may be employed to improve effectiveness of selection of patients for transcatheter closure of defects within the oval fossa.

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Ye, Jing, Guisuo Xia, Fang Liu, Ping Fu, and Qiangqiang Cheng. "Weld defect inspection based on machine vision and weak magnetic technology." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 9 (September 1, 2021): 547–53. http://dx.doi.org/10.1784/insi.2021.63.9.547.

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This study proposes a weld defect inspection method based on a combination of machine vision and weak magnetic technology to inspect the quality of weld formation comprehensively. In accordance with the principle of laser triangulation, surface information about the weldment is obtained, the weld area is extracted using mutation characteristics of the weld edge and an algorithm for identifying defects with abnormal average height in the weld surface is proposed. Subsequently, a welding seam inspection process is developed and implemented, which is composed of a camera, a structured light sensor, a magnetic sensor and a motion control system. Inspection results from an austenitic stainless steel weldment show that the method combining machine vision and magnetism can identify defect locations accurately. Comprehensive analysis of the test results can effectively classify surface and internal defects, estimate the equivalent sizes of defects and evaluate the quality of weld formation in multiple dimensions.

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Qi, Jiang. "Experimental Study of Interference Factors and Finite Element Simulation on Oil-Gas Pipeline Magnetic Flux Leakage Density." Advanced Materials Research 26-28 (October 2007): 1255–60. http://dx.doi.org/10.4028/www.scientific.net/amr.26-28.1255.

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Some methods of enhancing oil-gas pipeline magnetic flux leakage (MFL) detection technique are introduced in the paper. Some man-made defects or imperfections on the pipe surface are detected via the axial magnetization inspection vehicle along the pipeline. The magnetic dipole model of corrosion defect is stated and the important interference factors on magnetic flux leakage are analyzed. Finite element method is used to analyze and simulate normal defects on pipe surface, which can attribute to get natural defect MFL signal. The influence of benign pipeline artifacts (valves, welds, tees, flanges, etc.), pipe material and pipe wall, vehicle velocity, defect dimensions and interaction among defects, and so on are studied in detail. The magnetic flux leakage contour images or indication extraction maps are given and presented. These interference factors are compensated and solved. These approaches and results applied in the paper are contributed to the feature extraction and indication of pipeline abnormality. The results suggest that these approaches and conclusions are significantly effective for the pipeline magnetic flux leakage inspection.

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Linckelmann, Markus. "The dominant dimension of cohomological Mackey functors." Journal of Algebra and Its Applications 17, no. 12 (December 2018): 1850228. http://dx.doi.org/10.1142/s0219498818502286.

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We show that a separable equivalence between symmetric algebras preserves the dominant dimensions of certain endomorphism algebras of modules. We apply this to show that the dominant dimension of the category [Formula: see text] of cohomological Mackey functors of a [Formula: see text]-block [Formula: see text] of a finite group with a nontrivial defect group is [Formula: see text].

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36

Fragoulis, Socrates, Constantinos Contrafouris, Apostolos Thanopoulos, Konstantinos Kyriakoulis, and Sotiria Apostolopoulou. "Reversible right heart failure after redo operation of a post-traumatic Gerbode defect." Perfusion 35, no. 2 (July 21, 2019): 166–68. http://dx.doi.org/10.1177/0267659119859122.

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Introduction: Gerbode defect is a rare entity and represents a small percent of all congenital defects. If left untreated, right heart failure may occur. Case report: We describe a redo case of a 47-year-old patient complaining about the signs and symptoms of decompensating right heart failure after a surgically treated post-traumatic Gerbode defect 8 years prior. Discussion: Although it is described as a congenital defect, in clinical practice, results mostly as an iatrogenic complication after heart valve surgery, endocarditis, nodal ablation, or post-traumatic defect. Surgical correction is the treatment of choice independently of the provided cause. Dimensions, the position of the defect, are very important factors for the interventional approach. At 12 months post-operatively, the patient remained completely asymptomatic. He has an active life and presents all the echocardiographic metrics within normal values. Conclusion: We strongly recommend that in cardiac areas where high wall tension is applied, durable materials such as Dacron should be used. We also believe that a well-documented discussion with the patient, about his medical condition and his therapeutic alternatives, is imperative.

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Gherghetta, Tony, and Mikhail Shaposhnikov. "Localizing Gravity on a Stringlike Defect in Six Dimensions." Physical Review Letters 85, no. 2 (July 10, 2000): 240–43. http://dx.doi.org/10.1103/physrevlett.85.240.

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Somer, Frank L., G. S. Canright, and Theodore Kaplan. "Defect-unbinding transitions and inherent structures in two dimensions." Physical Review E 58, no. 5 (November 1, 1998): 5748–56. http://dx.doi.org/10.1103/physreve.58.5748.

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KHARRAT, M., M. N. ICHCHOU, O. BAREILLE, and W. ZHOU. "PIPELINE INSPECTION USING A TORSIONAL GUIDED-WAVES INSPECTION SYSTEM. PART 2: DEFECT SIZING BY THE WAVE FINITE ELEMENT METHOD." International Journal of Applied Mechanics 06, no. 04 (July 9, 2014): 1450035. http://dx.doi.org/10.1142/s1758825114500355.

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This paper represents the second part of the work that considers the identification and sizing of machined defects in a pipeline. This study deals with the torsional-mode reflection from defects and structural singularities in an industrial pipeline in order to perform the defect sizing. The wave finite element method (WFEM) is used to construct a numerical database of reflection coefficients from rectangular defects by varying thickness, axial and circumferential extents. Calculation is made depending on the frequency. The approximation of defects' sizes is carried out by sweeping the numerical database to find the suitable combination of dimensions for a given defect. The axial and circumferential extents are evaluated by fixed intervals for each possible thickness. Reflections from structural singularities (elbows, concrete blocks, clamps and welds) are also treated by comparing reflection coefficients obtained by the WFEM to those evaluated experimentally. Results show a good agreement for most of the structural singularities but not for the others.

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SHANG, C. H., Y. J. WANG, H. L. LUO, H. D. LI, and B. X. LIU. "TOPOLOGICAL AND SCALING PROPERTIES OF LINE DEFECTS IN Ni-Mo AMORPHOUS FILMS." Modern Physics Letters B 06, no. 30 (December 30, 1992): 1919–26. http://dx.doi.org/10.1142/s0217984992001629.

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Odd loops of line defects were firstly found in the heavily irradiated amorphous films. A developed defect usually comprises two types of enclosed curves with different charges. Topologically, these defects are one-dimensional self-avoiding manifolds with variable connectivity. It is revealed that an attractive self-avoiding reaction and point-like defects dominate the evolution behavior of line defects. Scaling analyses show that both types of line defects are of statistical self-similarity with fractal dimensions between 1 and 2. Moreover, A self-consistent theory via self-avoiding tethered manifolds is proposed to account for the static and dynamic properties of the observed defects.

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41

Zarazovskii, M., M. Borodii, and V. Kozlov. "Risk-Informed Approach to Structure Integrity Prediction and Optimization of In-Service Inspection of Heat Exchange Equipment with High Defect Statistics." Nuclear and Radiation Safety, no. 4(72) (December 18, 2016): 32–38. http://dx.doi.org/10.32918/nrs.2016.4(72).05.

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A physically and statistically based approach to steam generator heat exchange tube integrity assessment is proposed in the paper. The method is based on stochastic laws of crack dimensions distribution taking into account their growth, limit load model of cracked tube and SG plugging statistics. Based on the history of plugging tubes of specific SG, three statistical parameters have to be found: initial number of defects, initial defect size and defect growth rate. The developed method was used to predict HET failure for all Ukrainian SGs and to justify pressure reduction of hydrostatic test (HT) for primary side of NPPs with VVER. It is shown that pressure reduction does not practically increase the fracture probability during operation.

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Lee, Wen-Tzong, Jose Cosme, and Kevin Russell. "On the evaluation of a general model for optimum revolute cylindrical cylindrical cylindrical path generation." Transactions of the Canadian Society for Mechanical Engineering 42, no. 2 (June 1, 2018): 156–63. http://dx.doi.org/10.1139/tcsme-2017-0073.

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A general optimization model for the dimensional synthesis of defect free revolute cylindrical cylindrical cylindrical (RCCC) joint path generators is formulated, implemented and evaluated in this work. With this optimization model, RCCC dimensions required to approximate precision points are calculated. The model includes constraints to eliminate order, branch and circuit defects, which are common in dyad-based dimensional synthesis. Therefore, the originality of this work is the development of a general optimization model for RCCC path generation that simultaneously considers order, branch, and circuit defect elimination. This work demonstrates both the benefits and drawbacks realized when implementing the optimization model on a personal computer using the commercial mathematical analysis software package Matlab.

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ELLIS, JOHN, N. E. MAVROMATOS, and D. V. NANOPOULOS. "WORLD SHEET FORMULATION OF M THEORY." International Journal of Modern Physics A 13, no. 29 (November 20, 1998): 5093–112. http://dx.doi.org/10.1142/s0217751x98002377.

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We first review the interpretation of world sheet defects as D branes described by a critical theory in 11 dimensions, that we interpret as M theory. We then show that D-brane recoil induces dynamically an anti-de Sitter (AdS) space–time background, with criticality restored by a twelfth timelike dimension described by a Liouville field. Local physics in the bulk of this AdS11 may be described by an Osp (1|32, R) ⊗ Osp (1|32, R) topological gauge theory (TGT), with nonlocal boundary states in doubleton representations. We draw analogies with structures previously exhibited in two-dimensional black hole models. Wilson loops of "matter" in the TGT may be described by an effective string action, and defect condensation may yield string tension and cause a space–time metric to appear.

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Taylor, Seth T., John Mardinly, and Michael A. O'Keefe. "HRTEM Image Simulations for the Study of Ultrathin Gate Oxides." Microscopy and Microanalysis 8, no. 5 (October 2002): 412–21. http://dx.doi.org/10.1017/s1431927602020123.

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We have performed high resolution transmission electron microscope (HRTEM) image simulations to qualitatively assess the visibility of various structural defects in ultrathin gate oxides of MOSFET devices, and to quantitatively examine the accuracy of HRTEM in performing gate oxide metrology. Structural models contained crystalline defects embedded in an amorphous 16-Å-thick gate oxide. Simulated images were calculated for structures viewed in cross section. Defect visibility was assessed as a function of specimen thickness and defect morphology, composition, size, and orientation. Defect morphologies included asperities lying on the substrate surface, as well as “bridging” defects connecting the substrate to the gate electrode. Measurements of gate oxide thickness extracted from simulated images were compared to actual dimensions in the model structure to assess TEM accuracy for metrology. The effects of specimen tilt, specimen thickness, objective lens defocus, and coefficient of spherical aberration (Cs) on measurement accuracy were explored for nominal 10-Å gate oxide thickness. Results from this work suggest that accurate metrology of ultrathin gate oxides (i.e., limited to several percent error) is feasible on a consistent basis only by using a Cs-corrected microscope. However, fundamental limitations remain for characterizing defects in gate oxides using HRTEM, even with the new generation of Cs-corrected microscopes.

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Wang, C. M., W. Jiang, W. J. Weber, and L. E. Thomas. "Defect clustering in GaN irradiated with O+ ions." Journal of Materials Research 17, no. 11 (November 2002): 2945–52. http://dx.doi.org/10.1557/jmr.2002.0427.

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Transmission electron microscopy (TEM) was used to study microstructures formed in GaN irradiated with 600-keV O+ ions at room temperature. Three types of defect clusters were identified in the irradiated GaN: (i) basal-plane stacking faults with dimensions ranging from 5 to 30 nm, (ii) pyramidal dislocation loops, and (iii) local regions of highly disordered material. High-resolution TEM imaging clearly revealed that one type of the basal-plane stacking faults corresponded to insertion of one extra Ga–N basal plane in the otherwise perfect GaN lattice. The interpretation of these results indicated that interstitials of both Ga and N preferentially condensed on the basal plane to form a new layer of Ga–N under these irradiation conditions. The formation of these extended defects and their interactions with the point defects produced during irradiation contributed to a dramatic increase in the dynamic recovery of point defects in GaN at room temperature.

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46

Hu, Jue, Hai Zhang, Stefano Sfarra, Claudia Sergi, Stefano Perilli, Clemente Ibarra-Castanedo, Guiyun Tian, and Xavier Maldague. "Enhanced Infrared Sparse Pattern Extraction and Usage for Impact Evaluation of Basalt-Carbon Hybrid Composites by Pulsed Thermography." Sensors 20, no. 24 (December 14, 2020): 7159. http://dx.doi.org/10.3390/s20247159.

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Nowadays, infrared thermography, as a widely used non-destructive testing method, is increasingly studied for impact evaluation of composite structures. Sparse pattern extraction is attracting increasing attention as an advanced post-processing method. In this paper, an enhanced sparse pattern extraction framework is presented for thermographic sequence processing and defect detection. This framework adapts cropping operator and typical component extraction as a preprocessing step to reduce the dimensions of raw data and applies sparse pattern extraction algorithms to enhance the contrast on the defect area. Different cases are studied involving several defects in four basalt-carbon hybrid fiber-reinforced polymer composite laminates. Finally, comparative analysis with intensity distribution is carried out to verify the effectiveness of contrast enhancement using this framework.

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Arzano, Michele, and Tomasz Trześniewski. "Space-Time Defects and Group Momentum Space." Advances in High Energy Physics 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/4731050.

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We study massive and massless conical defects in Minkowski and de Sitter spaces in various space-time dimensions. The energy momentum of a defect, considered as an (extended) relativistic object, is completely characterized by the holonomy of the connection associated with its space-time metric. The possible holonomies are given by Lorentz group elements, which are rotations and null rotations for massive and massless defects, respectively. In particular, if we fix the direction of propagation of a massless defect in n+1-dimensional Minkowski space, then its space of holonomies is a maximal Abelian subgroup of the AN(n-1) group, which corresponds to the well known momentum space associated with the n-dimensional κ-Minkowski noncommutative space-time and κ-deformed Poincaré algebra. We also conjecture that massless defects in n-dimensional de Sitter space can be analogously characterized by holonomies belonging to the same subgroup. This shows how group-valued momenta related to four-dimensional deformations of relativistic symmetries can arise in the description of motion of space-time defects.

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De Waele, Wim, R. M. Denys, and Patrick de Baets. "Prediction of the Tolerable Defect Size for Strain Based Design." Materials Science Forum 475-479 (January 2005): 2731–34. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.2731.

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By using data of Curved Wide Plate (CWP) tests, a simple procedure to derive tolerable girth weld defect sizes is presented. The procedure involves prediction of the maximum tolerable defect size as a function of the applied remote plastic strain and the actual pipe and weld metal properties. Application of the methodology requires a reliable non-destructive testing technique that can detect the critical defect dimensions.

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Grys, Slawomir. "Determining the dimension of subsurface defects by active infrared thermography – experimental research." Journal of Sensors and Sensor Systems 7, no. 1 (March 20, 2018): 153–60. http://dx.doi.org/10.5194/jsss-7-153-2018.

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Abstract. This paper presents research into a method of processing thermal images aimed at detecting and characterizing material defects, or non-uniformities, of the internal structure of materials. Active thermography was chosen as the NDT method. Hidden defects were revealed by analysing the temperature field of the tested material's front surface which was externally excited with heating lamps. Background removal and image segmentation were applied to the last thermogram in the sequence recorded at the end of the heating phase. The paper focuses on the quality of determining lateral dimensions of subsurface flaws in a polymethylmethacrylate slab with bottom holes drilled to imitate flaws. The following accuracy-affecting factors were taken into account: defect depth, emissivity of the inspected surface as an input, user-set parameter for the IR camera, type of filtering used to eliminate the effect of non-uniformity when heating the object surface with an external source, and global and local thresholding as a segmentation method used for defect detection and sizing.

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B., Madhangi V., and Ramany C. "Cesarean scar defect and its association with clinical symptoms, uterine position and the number of cesarean sections." International Journal of Reproduction, Contraception, Obstetrics and Gynecology 9, no. 10 (September 25, 2020): 4091. http://dx.doi.org/10.18203/2320-1770.ijrcog20204293.

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Background: Caesarean scar defect (CSD), also called isthmocele or niche is a long-term complication, which can be asymptomatic or can give rise to chronic pelvic pain, dyspareunia and postmenstrual spotting. The objective of this study was to assess the association of CSD with clinical symptoms, position of the uterus and the number of caesarean sections.Methods: This was a prospective observational study done at a tertiary care teaching hospital from January 2019 to December 2019. The study included women with history of previous one or more caesarean sections with demonstrable CSD on transvaginal ultrasound. Various scar dimensions noted were width and depth of the scar. A deficiency ratio was calculated as a ratio of residual myometrium at the scar to the adjacent myometrium.Univariate analysis was done to assess the relationship of clinical symptoms with the defect parameters and number of previous caesarean sections. Multiple logistic regression analysis was done to find out the association between symptoms and number of previous caesarean sections with the scar defect dimensions.Results: The width, depth and deficiency ratio of the CSD were significantly higher in study subjects with a greater number of caesarean sections. Retroflexed uteri had larger CSD. There was no association of clinical features with the defect dimensions and the position of the uterus.Conclusions: CSD dimensions and deficiency ratio correlate with the number of previous caesarean sections and the position of the uterus. There was no association of clinical symptoms with the defect parameters.

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Journal articles on the topic 'Defect dimensions'

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