• Proceedings of the Korean Geotechical Society Conference
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• 1998.05a
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• pp.3-34
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• 1998

The stability condition of rock slopes is greatly affected by the geometry and strength parameters of discontinuities in the rock masses. Rock slopes Involving movement of rock blocks on discontinuities are failed by one or combination of the three basic failure modes-plane, wedge, and toppling. In rock mechanics, practically all the parameters such as the joint set characteristics, the rock strength properties, and the loading conditions are always subject to a degree of uncertainty. Therefore, a reasonable assessment of the rock slope stability has to include the excavation of the multi-failure modes, the consideration of uncertainties of discontinuity characteristics, and the decision on stabilization measures with favorable cost conditions. This study was performed to provide a new numerical model of the deterministic analysis, reliability analysis, and reliability-based optimization for rock slope stability. The sensitivity analysis was carried out to verify proposed method and developed program; the parameters needed for sensitivity analysis are design variables, the variability of discontinuity properties (orientation and strength of discontinuities), the loading conditions, and rock slope geometry properties. The design variables to be optimized by the reliability-based optimization include the cutting angle, the support pressure, and the slope direction. The variability in orientations and friction angle of discontinuities, which can not be considered in the deterministic analysis, has a greatly influenced on the rock slope stability. The stability of rock slopes considering three basic failure modes is more influenced by the selection of slope direction than any other design variables. When either plane or wedge failure is dominant, the support system is more useful than the excavation as a stabilization method. However, the excavation method is more suitable when toppling failure is dominant. The case study shows that the developed reliability-based optimization model can reasonably assess the stability of rock slopes and reduce the construction cost.

• Journal of Veterinary Clinics
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• v.28 no.3
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• pp.328-331
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• 2011

Two dogs presented to the Dueckso Animal Hospital with a history of intermittent lameness of the left forelimb. On physical examination, a visible antebrachial deformity that resulted in gross external rotation of approximately $90^{\circ}$ was observed in two dogs. Medial-lateral radiographic views revealed distal ulnar subluxation, cranial bowing of the radius, radial and ulnar shortening, and external rotation of the paw. A distal ulnar ostectomy and distal radial closing wedge osteotomy were performed in two dogs. A proximal ulnar osteotomy was performed, adjacent to the elbow joint in case 1. Then, the osteotomized site was supported with an intramedullary pin. A T-plate and cortical screws were applied to the proximal and distal radial segments after derotating the distal segment internally. Postoperative radiographic view verified the correction of the angular deformity in two dogs. The follow-up was completed by physical examination 6 and 10 months after surgery respectively. There was no evidence of lameness of the left forelimb in two dogs. Gross observation of the limb revealed an apparent appropriate correction of the rotational and angular deformity in two dogs.

• Computers and Concrete
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• v.24 no.5
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• pp.459-468
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• 2019

The stability and safety of concrete plug structure of diversion tunnel is crucial for the impoundment of upstream reservoir in hydropower projects. The ongoing Wudongde hydropower plant in China plans to adopt straight column plugs and curved column plugs to replace the traditional expanded wedge-shaped plugs. The performance of the proposed new plug structures under high water head is then a critical issue and attracts the attentions of engineers. This paper firstly studied the joint bearing mechanism of plug and surrounding rock mass and found that the quality and mechanical properties of the interfaces among plug concrete, shotcrete, and surrounding rock mass play a key role in the performance of plug structures. By performing geophysical and mechanical experiments, the contact state and the mechanical parameters of the interfaces were analyzed in detail and provide numerical analysis with rational input parameters. The safety evaluation is carried out through numerical calculation of plug stability under both construction and operation period. The results indicate that the allowable water head acting on columnar plugs is 3.1 to 7.4 times of the designed water head. So the stability of the new plug structure meets the design code requirement. Based on above findings, it is concluded that for the studied project, it is feasible to adopt columnar plugs to replace the traditional expanded wedge-shaped plugs. It is hoped that this study can provide reference for other projects with similar engineering background and problems.

• Journal of the Korean Orthopaedic Association
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• v.56 no.2
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• pp.157-163
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• 2021

Purpose: Xanthomatosis of the Achilles tendons is rare. In some patients, however, the lesions in the Achilles tendon need to be removed, which may be painful and disfiguring. While studies of successful surgical outcomes for the total resection and reconstruction of the Achilles tendon have been reported, reconstruction surgery has a technical challenge, and extended surgical exposures are required. This study analyzed five cases of bilateral xanthoma of the Achilles tendon, which was treated surgically using a wedge-shaped tendon-sparing approach to eliminate the need for tendon reconstruction. Materials and Methods: From July 2010 to May 2018, five patients with xanthomatosis in both Achilles tendons underwent wedge-shaped tendon preserving surgery. The average age was 49 years (range, 40-55 years), and the follow-up period was 21.4 months (range, 12-31 months). The patients consisted of three males and two females. Complications related to surgery were recorded. The outcome measures included the range of motion of the ankle joint, American Orthopaedic Foot and ankle Society (AOFAS) ankle/hindfoot score, and visual analogue scale (VAS) for overall satisfaction at the last follow-up. The availability of a single-limb heel raise and returning time to work were also measured. Results: Wound dehiscence that did not require secondary surgery was noted in one patient. At the last follow-up, the range of motion of the ankle joint was normal in all patients. The mean AOFAS ankle/hindfoot score was 91 (range, 85-96) and the VAS for the overall satisfaction ranged from 8 to 10. The average time between surgery and return to work was 27.6 days (range, 17-58 days) and all patients could perform a single-limb heel raise test. Conclusion: The tendon-sparing technique, which can preserve the anatomical functioning of the Achilles tendon, could be an excellent surgical approach because it has very promising functional and cosmetic surgical outcomes in patients with Achilles tendon xanthomatosis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.5
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• pp.383-390
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• 2020

Wedge locks have been widely used for spaceborne electronics for mounting or removal of a printed circuit board (PCB) during integration, test and maintenance process. However, it can basically provide a mechanical constraint on the edge of the board. Thus, securing a fatigue life of solder joint for electronic package by limiting board deflection becomes difficult as the board size increases. Previously, additional stiffeners have been applied to reduce the board deflection, but the mass and volume increases of electronics are unavoidable. To overcome the aforementioned limitation, we proposed an application of multi-layered PCB sheet with viscoelastic adhesive tapes to implement high-damping capability on the board. Thus, it is more advantageous in securing the fatigue life of package under launch environment compared with the previous approach. The basic characteristics of the PCB with the multi-layered sheet was investigated through free-vibration tests at various temperatures. The effectiveness of the proposed design was validated through launch vibration test at qualification level and fatigue life prediction of electronic package based on the test results.

• Journal of Korean Orthopaedic Sports Medicine
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• v.11 no.1
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• pp.30-36
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• 2012

Purpose: We compared the clinical and radiological results of meniscectomy with HTO or without HTO for degenerative medial meniscus posterior horn with varus deformity. Materials and Methods: Forty-two patients who had medial meniscus degenerative root tear with varus deformity more than 3 degrees were included for this study. Among them, 30 patients were performed meniscectomy combined with open wedge HTO and 12 patients were performed only meniscectomy without HTO. The mean follow-up period was 52.5 months. The clinical results were evaluated based on symptom improvement, patients' subjective satisfaction for surgery and HSS score. We also compared the osteoarthritic progression between the group on preoperative and at the final follow up radiographs. Results: Symptom improvement was achieved in 83.3% (25 cases) with HTO group and 66.7% (8 cases) without HTO group at final follow up with a significant difference. Patients' satisfaction was achieved in 83.3% (25 cases) with HTO group and 58.3% (7 cases) without HTO group which has a significant difference. The HSS score was improved in both group (90.8: with HTO group, 89.0: without HTO group) at the final follow up without significant difference. WOMAC score was improved in both groups at the final follow up without significant difference. There were no significant differences in the osteoarthritic progression between two groups. Conclusion: The good clinical result for treatment of patient who have medial meniscus degenerative root tear with varus deformity, proximal high tibial osteotomy is considered absolutely necessary. However, the progression of degenerative arthritis, its effect on long term follow up will be needed.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.522-527
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• 2004

Purpose: The purpose of this study was to evaluate the usefulness of single photon emission computed tomography (SPECT) of bone using Tc-99m MDP in the diagnosis of osteoporotic vertebral fractures. Materials and Methods: Thirty two patients with osteoporotic vertebral fracture were included in this study (mean age: $67{\pm}8$, male: 5, female: 27). Seventy nine vertebral fractures were detected (38 thoracic/thoracolumbar lesions and 41 lumbar lesions), which were classified by type of deformity (wedge, biconcave or compression). The patterns and locations of increased uptakes were examined and analyzed. Results: Forty seven wedge fractures, 20 biconcave fractures and 12 compression fractures were found. Diffuse and asymmetric uptakes were common in fractured bodies. More than one uptake were examined in 69 posterior elements of fractured vertebrae (87.3%) including 40 of 47 wedge fractures (85.1%), 17 of 20 biconcave fractures (85.0%) and 12 of 12 compression fractures (100%). Wedge fractures were predominant fracture in thoracic/thoracolumbar spine whereas incidence of biconcave or compression type war similar to that of wedge fracture in lumbar spine (p=0.04). Spinous process uptake was more frequently seen in lumbar lesions than thoracic/thoracolumbar lesions (p=0.009). Facet joint uptake in biconcave fracture was more common in lumbar spine (92.3%) than thoracic/thoracolumbar spine (57.1%). Spinous process uptake in biconcave fracture was also more frequently detected in lumbar spine (p=0.043). Conclusion: Bone SPECT was useful in the evaluation of osteoporotic vertebral fracture, especially posterior elements of vertebrae.

• Journal of the Korean Institute of Gas
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• v.15 no.6
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• pp.34-37
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• 2011

This paper presents sealing contact stress and deformation behaviors of an elastomeric contact seal for a pipe connection. In this study, a pipe connection is used by a joint nut and an elastomeric contact seal with a sealing interference of 0.2~0.5mm. A sealing interference in which compresses an elastomeric contact seal is generated by fastening a joint nut between two pipes. The FEM computed results show that the contact normal stress of contact model 1 with an inclined sealing surface is 1.5~1.75 times high in compared with that of contact model 2 with a parallel sealing surface. This indicates that the sealing contact surface recommends a wedge contact mode between two pipe connections for a high sealing compression stress.

• Journal of Veterinary Clinics
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• v.37 no.3
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• pp.163-167
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• 2020

A 13-month-old, 3.3 kg castrated male Shih-tzu presented with right hindlimb lameness. The physical examination revealed atrophy of the right thigh muscles, hyperextension of the stifle joint and external torsion of the tibia. On the radiographic examination, patella alta and genu recurvatum were observed. A biapical deformity of the tibia and external torsion of the distal tibia were detected by computed tomography (CT). A three-dimensional (3D) printed bone model was designed and constructed for the preoperative plan prior to surgery. Rectus femoris muscle transposition, femoral shortening ostectomy and open wedge osteotomy of the distal tibia were performed using hybrid external skele/t0al fixation (hybrid-ESF). A dynamic stifle flexion apparatus was used to prevent recurrence of a quadriceps contracture (QC). Intense physiotherapy was administered postoperatively. The dog began to use the affected limb one week after surgery. Functional improvement in the affected limb was observed, and full weight-bearing was possible at 3 months after surgery. Union of the osteotomy lines was observed at 3 months, and the stifle joint was fully movable at 7 months after surgery. Regarding the treatments for QC, these methods may be excellent candidates, as they do not lead to severe damage to the limb or amputation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5419-5424
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• 2014

A weld scallop is a small quadrant or half circle type hole installed in the weld line cross area for easy welding operation. Many types of T-bars with a scallop can be welded in a block assembly stage in shipbuilding. The difficulties arise from the fact that scallops are to be filled by build-up welding after welding of the cross line is complete. In this study, a non-scallop block joint welding method was developed using special type CBM (ceramic backing material). The wedge shaped CBM was devised to insert a CBM into just the V groove of weld line cross area without weld scallop. A saw-toothed shape was adopted for easy cutting of the unnecessary part in the CBM fitting process. The applicability of the developed method was verified through welding experiments based on the yard welding conditions.