• The Journal of Engineering Geology
• /
• v.28 no.4
• /
• pp.645-660
• /
• 2018

In the southeastern part of the Korean Peninsula, huge fault valleys, including the Yangsan and Ulsan faults, are recognized. These NNE-SSW trending lineaments are called as a whole Yangsan Fault System. However, this fault system is relatively poorly studied except the Yangsan and Ulsan faults. This study deduced the paleostress history based on the mutual cross-cutting relationships between geologic structures developed in the granite body near the Ilgwang fault, which is compared with previous studies. In the study area, four lineaments parallel to the Ilgwang fault are recognized, and three of them show evidences of faulting. In each lineament, both slip-senses of left-lateral and right-lateral are recognized. It indicates that these faults consistently underwent multiple deformations of inversion along the faults. The inferred paleostress directions based on the mutual cross-cutting relationships of the geological structures are as follows: 1) Tensile fractures developed in the late Cretaceous under the ENE-WSW direction of compressive stress, 2) NW-SE trending maximum horizontal principal stress generated conjugate strike-slip faults, and 3) selective reactivations of some structures were derived under the compression by the NE-SW trending principal stress.

• Clinics in Shoulder and Elbow
• /
• v.26 no.4
• /
• pp.357-365
• /
• 2023

Background: The purpose of this study was to evaluate the effect of concomitant open distal clavicle excision (DCE) on postoperative clinical outcomes and incidence of acromial and scapular stress fractures (ASFs) in patients with symptomatic acromioclavicular joint osteoarthritis (ACJ OA) undergoing reverse total shoulder arthroplasty (RTSA). Methods: A single-surgeon retrospective cohort study was conducted including patients who underwent primary elective RTSA with or without DCE from 2015 to 2019 with a minimum 6-month follow-up period. Shoulder active range of motion (AROM) and visual analog scale (VAS) pain were recorded preoperatively and postoperatively. ASFs and other adverse events were identified using postoperative notes and/or radiographs. Characteristics and outcomes were compared between the RTSA and RTSA-DCE groups. Results: Forty-six RTSA patients (mean age, 67.9±8.7 years; 60.9% male; mean follow-up, 24.9±16.6 months) and 70 RTSA-DCE patients (mean age, 70.2±8.9 years; 20.0% male; mean follow-up, 22.7±12.9 months) were included. There were no significant intergroup differences in rates of ASF (RTSA, 0.0% vs. RTSA-DCE, 1.4%; P=1.00), stress reactions (RTSA, 8.7% vs. RTSA-DCE, 11.4%; P=0.76), reoperation, revision, or infection (all P>0.05), or in pre-to-postoperative reduction in VAS pain (P=0.17) at latest follow-up. However, the RTSA-DCE group had greater pre-to-postoperative improvement in flexion AROM (RTSA, 43.7°±38.5° vs. RTSA-DCE, 59.5°±33.4°; P=0.03) and internal rotation (IR) AROM (P=0.02) at latest follow-up. Conclusions: Concomitant DCE in RTSA improves shoulder flexion and IR AROM, alleviates shoulder pain, and does not increase the risk of ASFs. Level of evidence: III.

• The Journal of the Petrological Society of Korea
• /
• v.19 no.2
• /
• pp.123-139
• /
• 2010

The properties of fracture system in Precambrian Jangbong schist and Mesozoic granites from Seokmo-do, Ganghwa-gun were investigated and analyzed. Most of the fractures measured at outcrops are nearly vertical or steeply dipping. Orientations of fracture sets in terms of frequency order are as follows: Set $1:N2^{\circ}E/77^{\circ}SE$, Set $2:N17^{\circ}E/84^{\circ}NW$, Set $3:N26^{\circ}E/64^{\circ}SE$, Set $4:N86^{\circ}W/82^{\circ}SW$, Set $5:N80^{\circ}W/77^{\circ}NE$, Set $6:N60^{\circ}W/85^{\circ}SW$, Set $7:N73^{\circ}E/87^{\circ}NW$, Set $8:N82^{\circ}W/53^{\circ}NE$, Set $9:N23^{\circ}W/86^{\circ}SW$, Set 10: $N39^{\circ}W/61^{\circ}NE$. Especially, the rose diagram of fracture strikes(N:240) indicates that there are two dorminant directions of N-S~NNE and WNW. These distribution pattern of fractures from Seokmo-do correponds with those of major lineaments from South Korea suggested in previous study. Meanwhile, the scaling properties on the length distribution of fracture populations have been investigated. First, fracture sets from Precambrian Jangbong schist and Mesozoic granites(north and south rock body) has been classified into five groups(group I~V) based on strike and frequency. Then, the distribution chart generalized the individual length-cumulative frequency diagram for above five groups were made. From the related chart, five subpopulations(group I~V) that closely follow a power-law length distribution show a wide range in exponents(-0.79~-1.53). These relative differences in exponent among five groups emphasizes the importance of orientation effect. From the related chart, the diagram of group III occupies an upper region among five groups. Finally, the distribution chart showing the chracteristics of the length frequency distribution for each rock body were made. From the related chart, the diagram of each rock body shows an order of porphyritic biotite granite < hornblende granodiorite < medium-grained biotite granite(south rock body) < medium-grained biotite granite(north rock body) < Precambrian Jangbong schist. From the related chart, the diagram of more older rock body in the formation age tends to occupy an upper region. Especially, the diagram of Precambrian Jangbong schist occupies an upper region compared with the diagrams of Mesozoic granites. These distributional chracteristics suggests that coexistence of new fracture initiation and growing of existing fractures corresponding with stress field acted since the formation of rock body.

• The Journal of the Petrological Society of Korea
• /
• v.15 no.4 s.46
• /
• pp.180-193
• /
• 2006

The Gilan area in the central-northern part of Uiseong Block of Cretaceous Gyeongsang Basin is composed of Precambrian metamorphic rocks, Triassic Cheongsong granite, Early Cretaceous Hayans Group, and Late Cretaceous-Paleocene igneous rocks. In this area, the faults of various directions are developed: Oksan fault of $NS{\sim}NNW$ trend, Gilan fault of NW trend, Hwanghaksan fault of WNW trend, and Imbongsan fault of EW trend. Several fracture sets with various geometric indicators, which determine their relative timing (sequence and coexistence relationships) and shear sense, we well observed in the Cheongsong granite, the basement of Gyeongsang Basin. The aim of this study is to determine the development sequence of extension fractures and the movement sense of shear fractures in the Gitan area on the basis of detailed analysis of their geometric indicators (connection, termination, intersection patterns, and cross-cutting relations). This study suggests that the fracture system of the Gilan area was formed at least through seven different fracturing events, named as Pre-Dn to Dn +5 phases. The orientations of fracture sets show (W) NW, NNW, NNE, EW, NE in descending order of frequency. The orientation and frequency patterns are concordant with those of faults around and in the Gilan area on a geological map scale. The development sequence and movement sense of fracture sets are summarized as follows. (1) Pre-Dn phase: extension fracturing event of $NS{\sim}NNW$ and/or $WNW{\sim}ENE$ trend. The joint sets of $NS{\sim}NNW$ trend and of $WNW{\sim}ENE$ trend underwent the reactivation histories of sinistral ${\rightarrow}$dextral${\rightarrow}$sinistral shearing and of (dextral${\rightarrow}$) sinistral shearing with the change of stress field afterward, respectively. (2) Dn phase: that of NW trend. The joint set experienced the reactivations of sinistral${\rightarrow}$dextral shearing. (3) Dn + 1 phase: that of $NNE{\sim}NE$ trend. The joint set was reactivated as a sinistral shear fracture afterward. (4) Dn +2 phase: that of $ENE{\sim}EW$ trend. (5) Dn +3 phase: that of $WNW{\sim}NW$ trend. (6) Dn+4 phase: that of NNW trend. The joint set underwent a dextral shearing after this. (7) The last Dn +5 phase: that of NNE trend.

• The Journal of the Korea Contents Association
• /
• v.9 no.4
• /
• pp.347-354
• /
• 2009

The stone pagodas include small internal spaces such as holes of Buddha's bones generally and the space's positions and sizes can make an influence on the maintenance of the stone pagoda. Also, inclined angles of the stone pagodas are an important factor to be considered to preserve them. In this paper, the Junghyesaji thirteen-storied stone pagoda subjected to its weight was analyzed through the finite element method to investigate the weakest location of the pagoda and study how size variation of internal spaces and slope variation influenced the weakest location. And criterions were proposed to examine the safety of the stone pagoda along the size variation of the internal spaces and the slope variation in view of the deflections and the stresses to examine fractures of the pagoda.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.31 no.4
• /
• pp.378-386
• /
• 2015

Overdenture has the advantage of improving the stability and retention of the denture but the abutment may be easily affected by caries or periodontal disease and the thin denture can be easily broken. The magnetic attachment overdenture has a high vertical retention but a low horizontal retention, thus, exerting a less disruptive force to the abutment or implant and shows less abrasion or damage compared to other mechanical retainers. Denture fractures in overdenture is caused by the thin denture base as the attachment is inserted, but it may also be caused by the difference in detrusion between soft tissue and hard tissue, and between an implant and a natural tooth. To compensate this shortcoming, a magnetic attachment with a silicone ball inserted in the magnet was developed as we report a successful case using this specific type of magnetic attachment overdenture.

• Journal of Ocean Engineering and Technology
• /
• v.25 no.2
• /
• pp.134-144
• /
• 2011

In this paper, the global study trends for material behaviors are investigated regarding the static and dynamic hardenings and final fractures of marine structural steels. In particular, after reviewing all of the papers published at the 4th and 5th ICCGS (International Conference on Collision and Grounding of Ship), the used hardening and fracture properties are summarized, explicitly presenting the material properties. Although some studies have attempted to employ new plasticity and fracture models, it is obvious that most still employed an ideal hardening rule such as perfect plastic or linear hardening and a simple shear fracture criterion with an assumed value of failure strain. HSE (2001) presented pioneering study results regarding the temperature dependency of material strain hardening at various levels of temperature, but did not show strain rate hardening at intermediate or high strain rate ranges. Nemat-Nasser and Guo (2003) carried out fully coupled tests for DH-36 steel: strain hardening, strain rate hardening, and temperature hardening and softening at multiple steps of strain rates and temperatures. The main goal of this paper is to provide the theoretical background for strain and strain rate hardening. In addition, it presents the procedure and methodology needed to derive the material constants for the static hardening constitutive equations of Ludwik, Hollomon, Swift, and Ramberg-Osgood and for the dynamic hardening constitutive equations of power from Cowper-Symonds and Johnson-Cook.

• Journal of Korean Foot and Ankle Society
• /
• v.16 no.2
• /
• pp.123-127
• /
• 2012

Purpose: The purpose of this study was to evaluate the clinical and radiographic results of the parallel-shaped modified Scarf osteotomy which is performed the Scarf osteotomy parallel to the shaft of the 1st metatarsal bone for hallux valgus deformities. Materials and Methods: We retrospectively reviewed 43 patients who had been treated by the parallel-shaped modified Scarf osteotomy for hallux valgus deformities between January 2006 and March 2011. We evaluated the results after this Scarf osteotomy with respect American Orthopaedic Foot & Ankle Society (AOFAS) scores, radiologic results by comparing intermetatarsal angle between 1stand 2nd metatarsal bones and hallux valgus angle. Results: We checked out the pre-operational and post-operational radiologic evaluation of intermetatarsal angle and hallux valgus angle between 1st and 2nd metatarsal bones. The mean AOFAS scores improved from 63.5 to 88.5. At final follow up, The hallux valgus angle improved from $31.4^{\circ}$ (16-52) to $9.0^{\circ}$ (3-13) and the intermetatarsal angle improved from $18.6^{\circ}$ (12-30) to $9.3^{\circ}$ (6-12) postoperatively. There was no case of major complications included recurrence of valgus deformity, correction or fixation failure and stress fractures. Conclusion: Our results suggest the our parallel-shaped modified Scarf osteotomy produces improved AOFAS scores, and effective correction of hallux valgus deformities. Our Scarf technique of osteotomy which is performed in parallel to the metatarsal bone minimizes the need for skill while more reliable and obtaining good correction and avoids associated complications.

• The Journal of Engineering Geology
• /
• v.14 no.2
• /
• pp.189-197
• /
• 2004

For a long time, groundwater has been used for a substitution for surface water but recently many problems have risen due to shortage of water resources and decrepitude of waterwells. Pneumatic fracturing technique is likely to be an efficient way to solve the problem of tile wells, in which pressure under the ground is applied to increase the amount of ground water. When applied pressure is given artificially to unstabilize the rock stress or to remove substances between fractures the groundwater can inflow. As the air pressure applied on the base rocks is stronger, permeability is getting higher, thus producing much groundwater than ever before. The result of this study show 15% increase of pumping rate in the P-5 well. After pneumatic fracturing pumping rate changed from 26m3/day to 30m3/day, drawdown rate increase from 51.12m to 56.58m, and specific yield also increased from 0.51m3/day to 0.53m3/day.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.3
• /
• pp.222-225
• /
• 2006

The treatment objective of mandibular fracture is a return to normal function. According to Champy, a rigid fixation of mandibular angle fracture is performed by using 4 or 6 holes titanium miniplates on the external oblique ridge of mandible. However, the limitations of metal plate such as hypersensitivity, interference with the cranio-facial growth of growing child, secondary bone resorption around the plate, foreign body reaction, declination of primary callus formation, and bone atrophy due to the lack of normal stress reaction of the bone have been reported. Recently, biodegradable miniplate has been introduced and used as an alternative to the metal plate despite its lower strength than that of the titanium plate and the side effect caused by the resorption in the body. In this study, 61 patients diagnosed as mandibular angle fracture and treated from Jan. 1998 to Dec. 2004 in our department have been reviewed. Metal plate fixation was used in 50 patients and biodegradable plate fixation in 11 patients on the external oblique ridge around the fractured mandibular angle according to the principle of monocortical osteosynthesis by Champy. We compared the incidence of side effects and the degree of bony union at the mandibular inferior border in two different fixation methods. In conclusion, we have found that one miniplate regardless of matter could provide enough strength to grasp bony fragments of the tension site and compress the inferior border of mandible without any complications.