• Title/Summary/Keyword: defects

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USAGE OF NASOLABIAL SKIN FLAPS FOR THE RECONSTRUCTION OF VARIOUS INTRAORAL DEFECTS (다양한 구강내 결손부 재건을 위한 비순피판의 활용)

  • Kim, Kyoung-Won;Lee, Eun-Young
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.29 no.1
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    • pp.71-78
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    • 2007
  • The nasolabial flap has been used for reconstruction of moderate size intraoral defects. The nasolabial fold area provides an ample supply of tissue with a good color and texture match. The nasolabial flap classified advancement flap, inferiorly-based flap, superiorly-based flap. The flap is based inferiorly, so that it can easily be rotated to the intraoral defects. The nasolabial flap is chosen for the repair of various intraoral defects because of its simple elevation, proximity to the defect and its rich subcutaneous blood supply of a island flap. The subjects were 6 patients with nasolabial flap, who had reconstruction of moderate size intraoral defects. We have found the inferiorly-based nasolabial flap with a subcutaneous pedicle useful in the primary repair of surgical defects of the buccal mucosa, edentulous mandibular ridge, maxillary alveolus area and soft palate in these patients. There was no complication except one case. Intraoral hair growth was a minor problem of this patient. We thought that the inferiorly-based nasolabial flap is a useful technique for reconstruction of various intraoral defects.

Evaluation of Surface and Sub-surface defects in Railway Wheel Using Induced Current Focused Potential Drops (집중유도 교류 전위차법을 이용한 철도차량 차륜의 표면과 내부 결함 평가)

  • Lee, Dong-Hyung;Kwon, Seok-Jin
    • Journal of the Korean Society for Railway
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    • v.10 no.1 s.38
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    • pp.1-6
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    • 2007
  • Railway wheels in service are regularly checked by ultrasonic testing, acoustic emission and eddy current testing method and so on. However, ultrasonic testing is sometimes inadequate for sensitively detecting the cracks in railway wheel which is mainly because of the fact of crack closure. Recently, many researchers have actively fried to improve precision for defect detection of railway wheel. The development of a nondestructive measurement tool for wheel defects and its use for the maintenance of railway wheels would be useful to prevent wheel failure. The induced current focusing potential drop(ICFPD) technique is a new non-destructive tasting technique that can detect defects in railway wheels by applying on electro-magnetic field and potential drops variation. In the present paper, the ICFPD technique is applied to the detection of surface and internal defects for railway wheels. To defect the defects for railway wheels, the sensor for ICFPD is optimized and the tests are carried out with respect to 4 surface defects and 6 internal defects each other. The results show that the surface crack depth of 0.5 mm and internal crack depth of 0.7 mm in wheel tread could be detected by using this method. The ICFPB method is useful to detect the defect that initiated in the tread of railway wheels

Hole Defects on Two-Dimensional Materials Formed by Electron Beam Irradiation: Toward Nanopore Devices

  • Park, Hyo Ju;Ryu, Gyeong Hee;Lee, Zonghoon
    • Applied Microscopy
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    • v.45 no.3
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    • pp.107-114
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    • 2015
  • Two-dimensional (2D) materials containing hole defects are a promising substitute for conventional nanopore membranes like silicon nitride. Hole defects on 2D materials, as atomically thin nanopores, have been used in nanopore devices, such as DNA sensor, gas sensor and purifier at lab-scale. For practical applications of 2D materials to nanopore devices, researches on characteristics of hole defects on graphene, hexagonal boron nitride and molybdenum disulfide have been conducted precisely using transmission electron microscope. Here, we summarized formation, features, structural preference and stability of hole defects on 2D materials with atomic-resolution transmission electron microscope images and theoretical calculations, emphasizing the future challenges in controlling the edge structures and stabilization of hole defects. Exploring the properties at the local structure of hole defects through in situ experiments is also the important issue for the fabrication of realistic 2D nanopore devices.

Vascularized bone grafts for post-traumatic defects in the upper extremity

  • Petrella, Giovanna;Tosi, Daniele;Pantaleoni, Filippo;Adani, Roberto
    • Archives of Plastic Surgery
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    • v.48 no.1
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    • pp.84-90
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    • 2021
  • Vascularized bone grafts (VBGs) are widely employed to reconstruct upper extremity bone defects. Conventional bone grafting is generally used to treat defects smaller than 5-6 cm, when tissue vascularization is adequate and there is no infection risk. Vascularized fibular grafts (VFGs) are mainly used in the humerus, radius or ulna in cases of persistent non-union where traditional bone grafting has failed or for bone defects larger than 6 cm. Furthermore, VFGs are considered to be the standard treatment for large bone defects located in the radius, ulna and humerus and enable the reconstruction of soft-tissue loss, as VFGs can be harvested as osteocutaneous flaps. VBGs enable one-stage surgical reconstruction and are highly infection-resistant because of their autonomous vascularization. A vascularized medial femoral condyle (VFMC) free flap can be used to treat small defects and non-unions in the upper extremity. Relative contraindications to these procedures are diabetes, immunosuppression, chronic infections, alcohol, tobacco, drug abuse and obesity. The aim of our study was to illustrate the use of VFGs to treat large post-traumatic bone defects and osteomyelitis located in the upper extremity. Moreover, the use of VFMC autografts is presented.

Reconstruction of Multiple Digital Defects by Temporary Syndactylization Using a Lateral Arm Free Flap

  • Sae Hwi Ki;Jin Myung Yoon;Tae Jun Park;M. Seung Suk Choi;Min Ki Hong
    • Archives of Plastic Surgery
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    • v.49 no.6
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    • pp.745-749
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    • 2022
  • Background Soft tissue defects of the multiple finger present challenges to reconstruction surgeons. Here, we introduce the use of a lateral arm free flap and syndactylization for the coverage of multiple finger soft tissue defects. Methods This retrospective study was conducted based on reviews of the medical records of 13 patients with multiple soft tissue defects of fingers (n = 33) that underwent temporary syndactylization with a microvascular lateral arm flap for temporary syndactylization from January 2010 to December 2020. Surgical and functional outcomes, times of flap division, complications, and demographic data were analyzed. Results Middle fingers were most frequently affected, followed by ring and index fingers. Mean patient age was 43.58 years. The 13 patients had suffered 10 traumas, 2 thermal burns, and 1 scar contracture. Release of temporary syndactyly was performed 3 to 9 weeks after syndactylization. All flaps survived, but partial necrosis occurred in one patient, who required a local transposition flap after syndactylization release. The mean follow-up was 15.8 months. Conclusion Coverage of multiple finger defects by temporary syndactylization using a free lateral arm flap with subsequent division offers an alternative treatment option.

Influence of oil pipe corrosion defects on the sealing performance of annular BOP

  • Dong, Liangliang;Tang, Yuan;Wang, Liuyang
    • Structural Engineering and Mechanics
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    • v.84 no.3
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    • pp.337-344
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    • 2022
  • Due to corrosion defects on the surface of the oil pipe, the sealing performance of the annular blowout preventer (BOP) decreases, and the leakage of toxic and harmful gases such as H2S and SO2 will threaten the safety of operators on the well. Therefore, this paper establishes the FE model for evaluating the sealing performance of BOP-oil pipe corrosion defects, which is based on the rubber large deformation theory and rubber core sealing mechanism, and designs the experiment of BOP sealing performance to verify the accuracy of the FE model. The sealing performance of BOP sealing oil pipe with corrosion defects is studied. The research results show that the sealing performance of BOP is more sensitive to the axial size of corrosion defects. With the increase of oil pipe outer diameter, the critical size of defects increases continuously. The sensitivity of radial and depth dimensions is low, When for 88.9 mm outer diameter oil pipe, the axial critical size of corrosion defect is 20 mm, the radial critical size is 16 mm and the critical depth is 2 mm. Fit the formula between the outer diameter of oil pipe and the piston increment. According to the formula, the operator can calculate the piston stroke increment required by the BOP to complete the sealing when the oil pipe is corroded.

Axially-compressed behavior of CFRP strengthening steel short columns having defects

  • Omid Yousefi;Amin Shabani Ammari
    • Structural Engineering and Mechanics
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    • v.91 no.1
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    • pp.49-61
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    • 2024
  • In recent decades, the majority of studies have concentrated on the utilization of Steel Square Hollow Section (SHS) columns, with minimal attention given to reinforcing columns exhibiting inherent defects. This study addresses this gap by introducing initial vertical and horizontal defects at three distinct locations (top, middle, and bottom) and employing Carbon-FRP for reinforcement. The research investigates the dimensional and positional impacts of these defects on the axial behavior of SHS columns. A total of 29 samples, comprising 17 with defects, 11 strengthened, and 1 defect-free control, underwent examination. The study employed ABAQUS modeling and conducted experimental testing. Results revealed that defects located at different positions significantly diminished the load-bearing capacity and initial performance of the steel columns. Axial loading induced local buckling and lateral rupture, particularly at the defect side, in short columns. Notably, horizontal (across the column's width) and vertical (along the column's height) defects in the middle led to the most substantial reduction in strength and load-bearing capacity. The axial compressive failure increased with the length-to-width ratio of the defect. Moreover, the application of four carbon fiber layers to strengthen the steel columns resulted in increased Energy Dissipation and a delayed onset of local buckling in the face of axial ruptures.

Congenital malformations in the vertebral column: associations and possible embryologic origins

  • Anneli M. Du Plessis;Quenton Wessels;Albert Van Schoor;Natalie Keough
    • Anatomy and Cell Biology
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    • v.55 no.4
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    • pp.399-405
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    • 2022
  • Cases of associations between random spinal congenital defects have previously been reported, yet several questions remain unanswered. Firstly, why are associations between what seems to be random combinations of vertebral malformations observed? Secondly, is there a common event or pattern that connects the associated defects? Therefore, this study aimed to identify congenital defects in the vertebral column and also to determine whether any associations, if present, between vertebral malformations exist. This article consequently discusses the possible embryological disruptions that may lead to the formation of various defects in the vertebral column. A random skeletal sample (n=187) was selected from the Pretoria Bone Collection housed in the Department of Anatomy, University of Pretoria (Ethics 678/2018). The sample was evaluated to determine the frequencies of spinal congenital defects in each set of remains. Identifiable congenital malformations were observed in 48.1% (n=90/187) of the sample. The results demonstrated a high probability of association between the different defects observed in the vertebral column. Findings are of value as they provide a reasonable explanation to why seemingly random cases of associations have been reported by several authors. This study is clinically relevant as severe spinal defects have been shown to have high morbidity in patients and mortality in infants.

Defects Diagnosis of Ball Bearings by Neural Network (신경회로망을 이용한 볼 베어링의 결함진단)

  • 양보석;최성필;최원호;김진욱
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.5
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    • pp.36-45
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    • 1994
  • This paper describes how to identify standard numbers and to diagnose defects of the ball bearings. The first stage of the networks is a procedures for identifying standard numbers of the bearings, and the next stage carries out the diagnosis of defects on the outer race and the inner race of bearings. The identification and the diagnosis of bearings were carried out by simulations and experiments.

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A Numeric Modelling Technique for the Shape Development of Fatigue Crack (피로 균열 형상 진전의 수치 모델링 기법에 관한 연구)

  • Han, Moon-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.2 s.95
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    • pp.225-233
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    • 1999
  • This paper describes a versatile finite element technique which has been used to investigate of wide range of structural defects of practical importance. The procedure automatically remeshes the three-dimensional finite element model during the stages of crack growth. Problems analyzed to date include the surface cracks in leak-before-break situations, the development of quarter-elliptical corner defects, planar semi-elliptical surface defects and the fatigue growth of defects.

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