• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.787-793
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• 2002

In this study, a bar impact test of low velocity was carried out to gain an insight into the damage mechanism and sequence induced in alumina plates(AD 85 and AD 90) under impact conditions. An experimental setup utilizing an instrumented long bar impact was devised, that can measure directly the impact force applied to the specimen and supply a compressive contact pressure to the specimen. During the bar impact testing, the influences of the contact pressure applied along the impact direction to the specimen on the fracture behavior were investigated. The measured impact force profiles explained well the damage behavior induced in alumina plates. The higher contact pressure to the specimen led to the less damage due to the suppression of radial cracks due to the increase in the apparent flexural stiffness of plate. It had produced the change of damage pattern developed in the specimen; from the radial cracks to the local contact stress dominant damage. It would contribute to the improvement of the ballistic property in ceramic plates. The observed results showed the following sequence in damage developed: The development of cone crack at impact region, the formation of radial cracks from the rear surface of plate depending on the plate thickness, the occurrence of crushing within the cone envelope and the fragmentation.

• Advances in materials Research
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• v.5 no.4
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• pp.299-318
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• 2016

Analytical investigations were performed of a longitudinal crack representing a cylindrical surface in circular shafts loaded in torsion with taking into account the non-linear material behavior. Both functionally graded and multilayered shafts were analyzed. It was assumed that the material is functionally graded in radial direction. The mechanical behavior of shafts was modeled by using non-linear constitutive relations between the shear stresses and shear strains. The fracture was studied in terms of the strain energy release rate. Within the framework of small strain approach, the strain energy release rate was derived in a function of the torsion moments in the cross-sections ahead and behind the crack front. The analytical approach developed was applied to study the fracture in a clamped circular shaft. In order to verify the solution derived, the strain energy release rate was determined also by considering the shaft complimentary strain energy. The effects were evaluated of material properties, crack location and material non-linearity on the fracture behavior. The results obtained can be applied for optimization of the shafts structure with respect to the fracture performance. It was shown that the approach developed in the present paper is very useful for studying the longitudinal fracture in circular shafts in torsion with considering the material non-linearity.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.117-117
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• 2008

• The Journal of Advanced Prosthodontics
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• v.9 no.1
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• pp.22-30
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• 2017

PURPOSE. The aim of this study was to investigate the effect of reinforcing materials on the fracture resistances of glass fiber mesh- and Cr-Co metal mesh-reinforced maxillary complete dentures under fatigue loading. MATERIALS AND METHODS. Glass fiber mesh- and Cr-Co mesh-reinforced maxillary complete dentures were fabricated using silicone molds and acrylic resin. A control group was prepared with no reinforcement (n = 15 per group). After fatigue loading was applied using a chewing simulator, fracture resistance was measured by a universal testing machine. The fracture patterns were analyzed and the fractured surfaces were observed by scanning electron microscopy. RESULTS. After cyclic loading, none of the dentures showed cracks or fractures. During fracture resistance testing, all unreinforced dentures experienced complete fracture. The mesh-reinforced dentures primarily showed posterior framework fracture. Deformation of the all-metal framework caused the metal mesh-reinforced denture to exhibit the highest fracture resistance, followed by the glass fiber mesh-reinforced denture (P<.05) and the control group (P<.05). The glass fiber mesh-reinforced denture primarily maintained its original shape with unbroken fibers. River line pattern of the control group, dimples and interdendritic fractures of the metal mesh group, and radial fracture lines of the glass fiber group were observed on the fractured surfaces. CONCLUSION. The glass fiber mesh-reinforced denture exhibits a fracture resistance higher than that of the unreinforced denture, but lower than that of the metal mesh-reinforced denture because of the deformation of the metal mesh. The glass fiber mesh-reinforced denture maintains its shape even after fracture, indicating the possibility of easier repair.

• Clinics in Shoulder and Elbow
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• v.5 no.1
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• pp.37-41
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• 2002

Purpose : To evaluate the effect of radial head resection on longevity in nonconstrained total elbow arthroplasty, Materials and Methods : The results of 20 cases of radial head replaced Pritchard ERS and 18 cases of radial head excised Kudo elbow was followed for 6 to 16 years, 10.6 years in average. The rate of loosening, osteolysis, radial head subluxation, joint dislocation and valgus deformity were compared between the two groups. Results'There was no exaggerated cubitus valgus in Pritchard ERS group. However there developed one case of delayed subluxation of radial head occurred in 6 years postoperatively, one case of loosening, and one case of sponta- neous fracture of humeral shaft due to osteolysis. In Kudo elbow group,5 cases (27.8%) showed exaggerated valgus deformity with instability. There were one case of loosening and one case of delayed dislocation occurred in a year postoperatively. Conclusion : The most clear feature of Kudo elbow was exaggerated cubitus valgus. However, the ostolysis was developed in both groups and there was no difference in rate of the other complications between the two groups.

• Archives of Reconstructive Microsurgery
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• v.12 no.2
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• pp.119-124
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• 2003

Introduction : The purpose is a retrospective evaluation of the clinical results of the radial forearm flap transfer for foot reconstruction. Materials and methods : We evaluated 21 cases with medical records including etiology, wound dimension, presence of infection, associated fracture, ischemic time of free flap, complication of donor and recipient site. The final results were evaluated with our clinical score (walking, shoe-in, cosmetic). Results : Defects were located on the heel (12 cases), dorsum of foot (4 cases) and sole (5 cases). Mean wound dimension was $7.56{\times}6.0cm$, and mean ischemic time of free flap was 94.5minute. There were superficial skin necrosis (1 case), recurrent ulceration (2 cases) in recipient site, and no complication in donor site but complaint about cosmetic problem (3 cases). The clinical score showed excellent in 14 cases, good in 4 cases, fair in 1 case and poor in 2 cases. Conclusion : We consider the radial forearm flap could provid the stable and durable restoration of normal foot contour without debulking in the foot reconstruction and achieved normal ambulation and cosmetic satisfaction.

• Journal of Acupuncture Research
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• v.35 no.1
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• pp.1-3
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• 2018

This case report demonstrates the beneficial effects of cupping therapy (CT) in a 35-year-old man who is diagnosed with a fracture of the radial shaft due to a motorcycle accident. One year after the treatment started, pseudoarthrosis developed in the radius and an autogenous iliac bone graft was performed. However, extension dysfunction in the wrist became evident. After another 6 months of physical therapy and rehabilitation, no improvements were observed. Therefore, CT and adjunctive electrostimulation were performed, after 30 days of treatment, marked recovery of muscle function and full wrist extension were observed, as determined by electromyography and a grade 5/5 on the Medical Research Council power of wrist extension scale. The results in this case study suggest that CT in conjunction with adjunctive electrostimulation, may accelerate functional recovery from postoperative radial palsy, and provide a useful alternative treatment in this situation.

• Clinics in Shoulder and Elbow
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• v.26 no.3
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• pp.312-322
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• 2023

Background: Silicone radial head prostheses (SRHP) are considered obsolete due to reports of frequent failure and destructive silicone-induced synovitis. Considering the good outcomes of modern non-radial silicone joint implants, the extent of scientific evidence for this negative view is unclear. The aim of this research was to systematically analyze the clinical evidence on complications and outcomes of SRHP and how SRHP compare to both non-SRHP and silicone prostheses of other joints. Methods: A systematic literature review was conducted through the Cochrane, PubMed, and Embase databases. Results: Eight cohort studies were included, consisting of 142 patients and follow-up periods ranging from 23 months to 8 years. Average patient satisfaction was 86%, range of 71%-100%, and 58 complications were seen, but no cases of synovitis. These outcomes were in line with non-SRHP. Four case series with 11 cases of synovitis were found, all due to implant fractures years to decades after implantation. Six systematic reviews of currently used non-radial silicone joint implants showed excellent outcomes with low complication rates. Conclusions: Since SRHP have satisfactory clinical results and an acceptable complication rate when selecting a patient group in suitable condition for surgical indications, it is considered that SRHP can still be chosen as a potential surgical treatment method in current clinical practice.

• Journal of Computational Design and Engineering
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• v.3 no.1
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• pp.63-70
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• 2016

Deep drawing is a forming process in which a blank of sheet metal is radially drawn into a forming die by the mechanical action of a punch and converted to required shape. Deep drawing involves complex material flow conditions and force distributions. Radial drawing stresses and tangential compressive stresses are induced in flange region due to the material retention property. These compressive stresses result in wrinkling phenomenon in flange region. Normally blank holder is applied for restricting wrinkles. Tensile stresses in radial direction initiate thinning in the wall region of cup. The thinning results into cracking or fracture. The finite element method is widely applied worldwide to simulate the deep drawing process. For real-life simulations of deep drawing process an accurate numerical model, as well as an accurate description of material behavior and contact conditions, is necessary. The finite element method is a powerful tool to predict material thinning deformations before prototypes are made. The proposed innovative methodology combines two techniques for prediction and optimization of thinning in automotive sealing cover. Taguchi design of experiments and analysis of variance has been applied to analyze the influencing process parameters on Thinning. Mathematical relations have been developed to correlate input process parameters and Thinning. Optimization problem has been formulated for thinning and Genetic Algorithm has been applied for optimization. Experimental validation of results proves the applicability of newly proposed approach. The optimized component when manufactured is observed to be safe, no thinning or fracture is observed.

• Korean Journal of Veterinary Research
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• v.51 no.4
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• pp.297-301
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• 2011

The racehorses that under arthroscopic surgery due to be injured his limbs were studied during exercise or training at Busan Race Park from 2005 to 2010. Rate of arthroscopic surgical treatments was 1.4% (63/4,642). Affected bones were radius, radial carpal bone, third carpal bone, proximal phalanx, third metacarpal bone, femur, tibia, proximal sesamoid bone and intermediate carpal bone. The lesions were fracture, chip fracture, slap fracture, osteochonrosis, and osteochondrotitis dissencans. Number of patients under arthroscopic surgery were 63. Success horses of returned to racetrack or tried to return to racetrack were 58, and 5 horses were in training or resting at the time of publication. Success horses of returned to their previous use in the patients were 49 horses (84.4%) and no returned to the racetrack were 9 horses (15.6%) in 58 horses.