• Title/Summary/Keyword: Strength evaluation method

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The study of nondestructive evaluation method of paper records materials by NIR spectroscopy (근적외선 분광분석을 이용한 종이기록물의 비파괴 특성평가 연구)

  • Han, Yoon-Hee;Shin, Yong-Min;Park, Soung-Be;Nam, Sung-Un;Kim, Hyo-Jin
    • Analytical Science and Technology
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    • v.23 no.3
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    • pp.304-311
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    • 2010
  • Near Infrared Spectroscopy (NIRs) has been applied for rapid and nondestructive paper measurement by replacing the current destructive method to the property of paper. Current standard methods for the property of paper were pH, moisture, breaking length, and folding endurance, which data were compared with spectrum of FT-NIR spectrometer. Various paper products such as copy, envelope, white, newspaper, as well as old paper produced around 1960~1980 were used as the sample. The correlation ($R^2$) and standard error of prediction (SEP) results for breaking length, folding endurance, moisture and pH are $R^2$=0.914, SEP=0.508, $R^2$=0.926, SEP=0.281, $R^2$=0.941, SEP=0.931, pH $R^2$=0.949, SEP= -0.0631, respectively. This result show that NIRs can be applied to practical application for nondestructive analysis of paper records materials.

LONG TERM EVALUATION OF VOLUME CHANGE IN FREE VASCULARIZED FIBULAR FLAP MANDIBLE RECONSTRUCTION (하악골 결손의 재건을 위한 혈행화된 비골 이식술에서의 장기간의 체적변화)

  • Kim, Yoon-Tae;Jeon, Seung-Ho;Yeom, Hak-Ryol;Ahn, Kang-Min;Myoung, Hoon;Hwang, Soon-Jung;Seo, Byoung-Moo;Choi, Jin-Young;Choung, Pill-Hoon;Kim, Myung-Jin;Lee, Jong-Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.32 no.2
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    • pp.138-141
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    • 2006
  • Introduction : In recent years, vascularized, i.e., living bone grafts, have been widely applied in the field of oral and maxillofacial surgery, as a method of treatment of congenital or acquired non-unions, and a large defects in mandible. The vascularized fibular graft has been especially used for this purpose because of its shape and mechanical strength. The postoperative hypertrophy of grafted fibula is of particular interest to us. Material and methods : This study was undertaken to determine the volume change(indirect methods) and radiographic appearance of a free vascularized fibular graft as it responds to the mechanical and physiologic features of its new environment. In order to elucidate the long term effect on fibular mass after mandibular reconstruction, change in various method of volume change was utilized as indirect measure of change in long-term. Results : The younger the patient, the more prominent and rapid the hypertrophy of the graft. the hypertrophy of the graft never exceeded the diameter of the recipient bone, except for callus enlargement after stress fracture of the grafted bone. Conclusion : Etiologic explanations for this phenomenon have not been clarified in the previeous literature. some of the factors implicated include a periosteal reaction or new bone formation, as seen at the onset of bone union after a fracture in a child, a reaction to the mechanical loading on the graft and a reaction to the circulatory changes resulting from the grafting procedure.

Beneficial effects of ton-bag and wire-steel pallet on postharvest handling of onion and the cost evaluation (톤백 및 와이어철제파렛트 이용에 따른 양파의 수확후관리 효율성 증대와 경제성 평가)

  • Kwon, Young-Deuk
    • Food Science and Preservation
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    • v.24 no.7
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    • pp.915-922
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    • 2017
  • This study aimed in onion production by evaluating cost and labor efficiencies of onion storage methods using either a ton-bag or a wire-steel pallet. New methods using ton-bag and wire-steel pallets were developed and applied to postharvest tasks, such as harvest packaging, transportation, and storage. The storage parameters evaluated for their effect on the logistics of onion production were: working duration, working hours, and cost expenditure. The longitudinal tensile strength of the ton-bag developed in this study was 16% higher than that of the conventional ton-bag. The wire-steel pallet developed in this study had 10% more storage capacity in a low-temperature storage room, and its truck loading capacity was more than doubled compared to that of the conventional steel pallet. There was no difference in the wasting rate during bulk storage between the newly developed wire-steel pallet and the conventional steel pallet, for 500 kg of onions. However, the bulk storage of 1,000 kg of onions using the wire-steel pallet was not found to be suitable, because the wasting rate of onions stored using the wire-pallet was 3.7% higher than that of onions stored using a conventional steel pallet. The time and the total investing costs for the bulk method decreased by 50.1% and 46.1%, respectively, compared to those for conventional harvest. In the bulk storage using the wire-steel pallet, the total storage cost decreased by 28.8%. Thus, it is estimated that we could have saved 18.3 billion won if the wire-steel pallet method about 30% of the total onion production (1,298,749 M/T) in 2016.

Comparative Study on Applicable Consolidants for Archival Objects of Copper Alloy (동합금 행정박물에 적용 가능한 표면강화처리제 비교 연구)

  • Park, Chang-Su;Cho, Hyun-Kyung;Cho, Nam-Chul;Kang, Dai-Ill
    • Journal of Conservation Science
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    • v.28 no.1
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    • pp.53-62
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    • 2012
  • The archival objects are tangible evidence related to the public service. They are unique and offer information representing the specific events, time or person. The archival objects as modern cultural heritage do not have the guideline to classify, manage and conserve them. Especially, it is difficult to apply general conservation process for burial artifacts, because there are few study example of conservation for metal archival objects and they have complex administrative value. We tried to find suitable material and application method for consolidation of copper alloy archival object. We choose three kinds of wax and acrylic resin for burial artifacts and had done comparative analysis of their characterizations following kinds and coating methods. As a result of evaluation by several surface analysis such as optical microscope, measuring film thickness, adhesive strength, contact angle and yellowing test, acrylic resin can use to archival objects of copper alloy, effectively but the method of heating after dip-coating with Wax B used before can get best effect of consolidation.

Horizontal Behavior Characteristics of Umbrella-Type Micropile Applied in Sandy Soil Subjected to Seismic Motion (사질토 지반에 설치된 우산형 마이크로파일의 지진 시 수평거동 특성)

  • Kim, Soo-Bong;Son, Su Won;Kim, Jin Man
    • Journal of the Korean GEO-environmental Society
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    • v.21 no.7
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    • pp.5-16
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    • 2020
  • Currently, the seismic design standards have been strengthened due to the occurrence of the Gyeongju and Pohang earthquake, and seismic performance evaluation of existing facilities is being conducted. It aims to secure a seismic performance effect during earthquakes by improving the micro-pile method, which can be constructed in limited confined places while minimizing damage to existing facilities. The improvement method is to construct all the piles in the square-tray-type plate on the top of the pile by constructing the slope pile in the form of an umbrella around the vertical pile, the main pillar. In this paper, the numerical analysis was performed to analyze the horizontal displacement behavior of an umbrella-type micropile for various real-measurement seismic waves in sandy soil. As a result of numerical analysis, the softer the ground, the better the effect of horizontal resistance of umbrella-type micropile. The horizontal displacement reduction effect was pronounced when the embedded depth was 15 m or more at the same ground strength, and it was found to be effective in earthquakes if it was settled on the ground with an N value of 30 or more. The embedded depth and horizontal displacement suppression effect of the micropile was proportional. Generally, the weaker the ground, the greater the displacement suppression effect. Umbrella-type micropile had a composite resistance effect in which the vertical pile resists the moment and inclined pile resists the axial force.

Study on the Testing Method for Setting Time of Set Accelerating Agent Using Shotcrete by Gilmour Needles (길모어침에 의한 숏크리트용 급결제의 품질시험방법에 대한 고찰)

  • Kim, Chun Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.195-200
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    • 2011
  • KS F 2782 (for shotcrete accelerators) standard cross-section of tunnel construction or repair is a reinforcement used in the field of shotcrete accelerators as a criterion in assessing shotcrete performance. Thus, KS F 2782 by standard accelerator will determine the nature of the product of concrete accelerators that will be used to record variations in the product roles, through determination of the quality of the experimental method to identify only the quality of the many variables that exist. This evaluation standard has so far distinguished accelerator products in indoor experiments that do not meet quality standards but were mostly for an on-site accelerator mixed with the shotcrete after being quite satisfied with the level of quality in a certain number of products. This observation is derived from the results of an indoor experiment considered to verify whether the site is suitable for indoor experiments, and whether its actual location in the city is relevant to the accelerator quality, to find a way to test if it fits. This study centers on the material conditions of the shotcrete accelerator and a variety of experimental results, and used the Gilmore needle to compare the compressive strength and KS F 2782 specification of the accelerator as a means to ensure product quality conformity analysis and for further research experiments. In conclusion, a portion of KS F 2782 standard that fixes the problems that can be resolved from the ground up as a whole is not a review for the domestic reality. As an indoor experiment to ensure uniformity in the field when applied in a sufficient correlation, complement must be in place.

An Experimental Study on the Performance of RC Beam according to the Rapid Freezing and Thawing Test Method in the Air (기중 급속 동결 융해 시험 방법에 따른 철근콘크리트 보의 성능 실험 연구)

  • Kim, Sang-Woo;Lee, Dong-Ju;Kim, Kyeong-Min;Kim, Jin-Sup
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.4
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    • pp.46-55
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    • 2021
  • Concrete structures can cause various problems as the number of common years increases when exposed to external extreme climate conditions. Among these problems, freezing and thawing occur due to the action of extreme climate factors such as heavy rain and heavy snow, which have become the most problematic in recent years. In this study, we present a rapid freezing and thawing test method of concrete in the air, referring to KS F 2456, as Seoul exhibits very dry weather during the period of freezing and thawing. Concrete test specimens and RC beams were fabricated to perform rapid freezing and thawing of 0, 100, 200, and 300 cycles, and the performance evaluation confirmed the degradation of each subject in material and member units. The design strength of 24 MPa, which performs rapid freezing and thawing in the air up to 300 cycles, decreases by 5.24 MPa (21%), and as rapid freezing and thawing in the air increases the stress burden on reinforced concrete bending members, reducing the energy absorption (dissipation) ability of structures due to earthquakes.

Comparison of Liquefaction Assessment Results with regard to Geotechnical Information DB Construction Method for Geostatistical Analyses (지반 보간을 위한 지반정보DB 구축 방법에 따른 액상화 평가 결과 비교)

  • Kang, Byeong-Ju;Hwang, Bum-Sik;Bang, Tea-Wan;Cho, Wan-Jei
    • Journal of the Korean Geotechnical Society
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    • v.38 no.4
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    • pp.59-70
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    • 2022
  • There is a growing interest in evaluating earthquake damage and determining disaster prevention measures due to the magnitude 5.8 earthquake in Pohang, Korea. Since the liquefaction phenomena occurred extensively in the residential area as a result of the earthquake, there was a demand for research on liquefaction phenomenon evaluation and liquefaction disaster prediction. Liquefaction is defined as a phenomenon where the strength of the ground is completely lost due to a sudden increase in excess pore water pressure caused due to large dynamic stress, such as an earthquake, acting on loose sand particles in a short period of time. The liquefaction potential index, which can identify the occurrence of liquefaction and predict the risk of liquefaction in a targeted area, can be used to create a liquefaction hazard map. However, since liquefaction assessment using existing field testing is predicated on a single borehole liquefaction assessment, there has been a representative issue for the whole targeted area. Spatial interpolation and geographic information systems can help to solve this issue to some extent. Therefore, in order to solve the representative problem of geotechnical information, this research uses the kriging method, one of the geostatistical spatial interpolation techniques, and constructs a geotechnical information database for liquefaction and spatial interpolation. Additionally, the liquefaction hazard map was created for each return period using the constructed geotechnical information database. Cross validation was used to confirm the accuracy of this liquefaction hazard map.

Evaluation of Biomechanical Properties of Fractured Adjacent Soft Tissue Due to Fracture Site Spacing During Closed Reduction After Forearm Fracture: Finite Element Analysis (전완 골절 후 도수 정복 시 골절 부위 간격에 따른 골절 인접 연부 조직의 생체역학적 특성 평가: 유한요소해석)

  • Park, Jun-Sung;Lee, Sang Hyun;Song, Chanhee;Ro, Jung Hoon;Lee, Chiseung
    • Journal of Biomedical Engineering Research
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    • v.43 no.5
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    • pp.308-318
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    • 2022
  • The purpose of this study is to evaluate the biomechanical properties of fractured adjacent soft tissue during closed reduction after forearm fracture using the finite element method. To accomplish this, a finite element (FE) model of the forearm including soft tissue was constructed, and the material properties reported in previous studies were implemented. Based on this, nine finite element models with different fracture types and fracture positions, which are the main parameters, were subjected to finite element analysis under the same load and boundary conditions. The load condition simulated the traction of increasing the fracture site spacing from 0.4 mm to 1.6 mm at intervals of 0.4 mm at the distal end of the radioulnar bone. Through the finite element analysis, the fracture type, fracture location, and displacement were compared and analyzed for the fracture site spacing of the fractured portion and the maximum equivalent stress of the soft tissues adjacent to the fracture(interosseous membrane, muscle, fat, and skin). The results of this study are as follows. The effect of the major parameters on the fracture site spacing of the fractured part is negligible. Also, from the displacement of 1.2 mm, the maximum equivalent stress of the interosseous membrane and muscle adjacent to the fractured bone exceeds the ultimate tensile strength of the material. In addition, it was confirmed that the maximum equivalent stresses of soft tissues(fat, skin) were different in size but similar in trend. As a result, this study was able to numerically confirm the damage to the adjacent soft tissue due to the fracture site spacing during closed reduction of forearm fracture.

A Study on Evaluation of Rock Brittleness Index using Punch Penetration Test (압입시험을 이용한 암석의 취성도 평가에 관한 연구)

  • Hoyoung Jeong
    • Tunnel and Underground Space
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    • v.33 no.1
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    • pp.29-41
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    • 2023
  • The brittleness of rocks plays an important role in determining the fragmentation and failure behavior of rock. However, there is still no standard method to evaluate the brittleness of rock, and previous studies have suggested the several definitions for estimation of brittleness of rock. Even in the process of mechanical rock excavation and drilling, the brittleness of rock is considered as an important property for evaluating the excavation efficiency of mechanical excavators or boreability of rock. The previous studies have been carried out to investigate the correlation between different brittleness of rock and cutting efficiency and boreability of rock. This study introduced a method for calculating the brittleness of rock from punch penetration test, and analyzed the correlation between the brittleness of rock calculated by the uniaxial compressive and Brazilian tensile strengths and that from punch penetration test. From the results of correlation analysis, the relationship between various brittleness was confirmed, and it was found that PSI and BI3 showed a good correlation with the strength-based brittleness index. In addition, the results indicated that B3 and B4 are suitable to represent the brittleness of rock in the field of mechanical rock excavation.