• Title/Summary/Keyword: Strength evaluation

Search Result 4,809, Processing Time 0.045 seconds

Comparative Analysis of Double Bundle and Single Bundle ACL Reconstruction with Tibialis Anterior Allograft (동종건을 이용한 단일다발 및 이중다발 전방십자인대 재건술의 비교 분석)

  • Kim, Deok-Weon;Lee, Kang;Kim, Young-Woo;Yang, Sang-Jin;Seo, Jeong-Gook;Kim, Jin-Goo
    • Journal of the Korean Arthroscopy Society
    • /
    • v.12 no.3
    • /
    • pp.198-204
    • /
    • 2008
  • Purpose: The purpose of this study is to analyze the merits and demerits of double bundle reconstruction and achieve improvements hereafter, by comparing the results of double bundle and single bundle reconstruction using tibialis anterior allograft. Materials and Methods: Twenty seven patients were divided to undergo either double bundle(n=14) or single bundle(n=13) reconstruction with tibialis anterior allograft tendon. The evaluation methods were AP laxity with KT-2000 arthrometer, isokinetic knee strength measurements, pivot-shift test, IKDC subjective score, Lysholm knee score, Tegner activity score, radiographic evaluations with postoperative MRI, and second look arthroscopy. Results: Lysholm knee score and Tegner activity score were significantly better in double bundle reconstruction. In pivot-shift test, single bundle reconstruction was evaluated as grade 0 in 10 of the knees, grade 1 in 1, and grade 2 in 2. Double bundle reconstruction was evaluated as grade 0 in 13, and grade 2 in 1. In second look arthroscopy, single bundle was evaluated as excellent in 6 of the knees, fair in 7, anteromedial bundle of double bundle reconstruction was excellent in 13 and fair in 1, and posterolateral bundle was excellent in 4, fair in 9, and poor in 1. There were no significant differences in other evaluations. Conclusion: Favorable outcome may be expected with double bundle reconstruction of ACL. However there are still need for improvement in terms of reconstruction technique and rehabilitation protocol to reduce PL bundle injury.

  • PDF

Evaluation of TOF MR Angiography and Imaging for the Half Scan Factor of Cerebral Artery (유속신호증강효과의 자기공명혈관조영술을 이용한 뇌혈관검사에서 Half Scan Factor 적용한 영상 평가)

  • Choi, Young Jae;Kweon, Dae Cheol
    • Journal of the Korean Magnetics Society
    • /
    • v.26 no.3
    • /
    • pp.92-98
    • /
    • 2016
  • To aim of this study was to assess the full scan and half scan of imaging with half scan factor. Patients without a cerebral vascular disease (n = 30) and were subject to the full scan half scan, and set a region of interest in the cerebral artery from the three regions (C1, C2, C3) in the range of 7 to 8 mm. MIP (maximum intensity projection) to reconstruct the images in signal strength SNR (signal to noise ration), PSNR (peak signal noise to ratio), RMSE (root mean square error), MAE (mean absolute error) and calculated by paired t-test for use by statistics were analyzed. Scan time was half scan (4 minutes 53 seconds), the full scan (6 minutes 04 seconds). The mean measurement range (7.21 mm) of all the ROI in the brain blood vessel, was the SNR of the first C1 is completely scanned (58.66 dB), half-scan (62.10 dB), a positive correlation ($r^2=0.503$), for the second C2 SNR is completely scanned (70.30 dB), half-scan (74.67 dB) the amount of correlation ($r^2=0.575$), third C3 of a complete scan SNR (70.33 dB), half scan SNR (74.64 dB) in the amount of correlation between the It was analyzed with ($r^2=0.523$). Comparative full scan with half of SNR ($4.75{\pm}0.26dB$), PSNR ($21.87{\pm}0.28dB$), RMSE ($48.88{\pm}1.61$), was calculated as MAE ($25.56{\pm}2.2$). SNR is also applied to examine the half-scans are not many differences in the quality of the two scan methods were not statistically significant in the scan (p-value > .05) image takes less time than a full scan was used.

Experimental Evaluation of Bi-directionally Unbonded Prestressed Concrete Panel Impact-Resistance Behavior under Impact Loading (충돌하중을 받는 이방향 비부착 프리스트레스트 콘크리트 패널부재의 충돌저항성능에 대한 실험적 거동 평가)

  • Yi, Na-Hyun;Lee, Sang-Won;Lee, Seung-Jae;Kim, Jang-Ho Jay
    • Journal of the Korea Concrete Institute
    • /
    • v.25 no.5
    • /
    • pp.485-496
    • /
    • 2013
  • In recent years, frequent terror or military attacks by explosion or impact accidents have occurred. Examplary case of these attacks were World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. These attacks of the civil infrastructure have induced numerous casualties and property damage, which raised public concerns and anxiety of potential terrorist attacks. However, a existing design procedure for civil infrastructures do not consider a protective design for extreme loading scenario. Also, the extreme loading researches of prestressed concrete (PSC) member, which widely used for nuclear containment vessel, gas tank, bridges, and tunnel, are insufficient due to experimental limitations of loading characteristics. To protect concrete structures against extreme loading such as explosion and impact with high strain rate, understanding of the effect, characteristic, and propagation mechanism of extreme loadings on structures is needed. Therefore, in this paper, to evaluate the impact resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, impact tests were carried out on $1400mm{\times}1000mm{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PS), prestressed concrete with rebar (PSR, general PSC) specimens. According to test site conditions, impact tests were performed with 14 kN impactor with drop height of 10 m, 5 m, 4 m for preliminary tests and 3.5 m for main tests. Also, in this study, the procedure, layout, and measurement system of impact tests were established. The impact resistance capacity was measured using crack patterns, damage rates, measuring value such as displacement, acceleration, and residual structural strength. The results can be used as basic research references for related research areas, which include protective design and impact numerical simulation under impact loading.

Freeze-thaw Resistance Estimation of Concrete using Surface Roughness and Image Analysis (콘크리트의 동결융해 저항성 추정을 위한 표면 거칠기 및 이미지 분석의 적용성)

  • Lee, Binna;Lee, Jong Suk
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.22 no.3
    • /
    • pp.1-7
    • /
    • 2018
  • As part of a research dedicated to the field evaluation of the durability of concrete subjected to freezing-thawing, this study analyzes the relationship between the surface roughness and the relative dynamic elastic modulus through image analysis. Four mix compositions with water-to-binder ratios (W/B) of 40%, 50%, 60% and 70% and without AE agent were considered to provoke early freezing. The basic physical properties of the mixes including the relative dynamic elastic modulus and the compressive strength were first evaluated experimentally according to W/B. Then, tests were performed to measure the surface roughness followed by photographs and SEM image analysis. The measured surface roughness tended to increase with larger number of freezing-thawing cycles regardless of W/B. The relative dynamic elastic modulus appeared to increase gradually with the number of cycles for the relatively denser mixes with W/B of 40% and 50%. Besides, the surface roughness increased only at rupture for the mixes with W/B of 60% and 70%. Moreover, the analysis of the photographs of the surface of the mixes with W/B of 40% and 50% revealed that the degradation progressed gradually from the surface with the freezing-thawing cycles. However, for the mixes with W/B of 60% and 70%, apparent change of the surface remained very insignificant until rupture at which damage like cracking could be observed. Consequently, the analysis of surface photograph or the measurement of the surface roughness presented some limitation in assessing the degree of freezing-thawing-induced degradation in case of relatively porous specimens. On the other hand, the photograph and surface roughness appeared to be sufficient for assessing such degradation for the mixes with W/B of 40% and 50%. Accordingly, the image of the surface and the surface roughness are potentially applicable on site for the assessment of freezing-thawing damages in relatively dense mixes.

Evaluation of Performance Based Design Method of Concrete Structures for Various Climate Changes (다양한 기후변화에 따른 콘크리트 구조물의 성능중심형 설계 평가)

  • Kim, Tae-Kyun;Shim, Hyun-Bo;Ahn, Tae-Song;Kim, Jang-Ho Jay
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.1 no.1
    • /
    • pp.8-16
    • /
    • 2013
  • Currently, global warming has advanced by the usage of fossil fuels such as coal and petroleum. and the atmosphere temperature in the world of 100 years(1906~2005) has been risen $0.74^{\circ}C{\pm}0.18^{\circ}C$, IPCC announced that the global warming effect of last decade was nearly doubled compared to the changes($0.07^{\circ}C{\pm}0.02^{\circ}C$/10year) in the past 100 years. Moreover, due to the global warming, heat wave, heavy snow, heavy rain, super typhoon, were caused and are increasing to happen in the world continuously causing damages and destruction of social infrastructures, where concrete structures are suffering deterioration by long-term extreme climate changes. to solve these problems, the new construction technology and codes are necessary. In this study, to solve these problems, experiments on a variety of cases considering the temperature and humidity, the main factors of climate factors, were performed, and the cases are decided by temperature and humidity. The specimens were tested in compressive strength test and split tensile test by the curing age(3,7,28 days) morever, performance based design(PBD) method was applied by using the satisfaction curve developed from the experiment date. PBD is the design method that gathers the current experimental analysis and past experimental analysis and develops the material properties required for the structure, and carries out the design of concrete mix, and it is recently studied actively worldwide. Also, it is the ultimate goal of PBD to design and perform on structures have sufficient performance during usage and to provide the problem solving for various situations, Also, it can achieve maximum effect in terms of functionality and economy.

A Study on Results of Rehabilitation Therapy of Patients with Head Injury (두부손상 환자의 재활치료 결과에 관한 연구)

  • Kim, Su-Min;Lim, Hye-Hyeon
    • Journal of Korean Physical Therapy Science
    • /
    • v.1 no.1
    • /
    • pp.135-144
    • /
    • 1994
  • The authors studied therapeutic effects and related clinical data retrospectively on a series of 48 consecutive patients with head injury who were referred to physical therapy and occupational therapy, Kosin University Medical Center during 1 year, from March, 1993. through March, 1994. The conclusions were as follows : 1. Average age of the subject patients was 50.6 years, their age remped from 14 to 72 years, and the incidence between male and femele was 1:1.1. 2. In respect to the educational level high school graduates showed the highest incidence 18 (39.1 %) of 46 cases, and in respect to economy level, middle class revealed the highest incidence, 31(64.6 %) in 48 cases. 3. The HBP was the most common cause of spontaneity injury, disclosing 19 cases in 35 patients(54.3%), whereas the main cause of traumatic injury was a traffic accident, 7 cases ( 53.8 %) in 13 patients. 4. As for the region of injury in the cases of spontaneity ICH was 14 persons (40%). In the cases of trauma, hematoma was seen in 6 cases(42.2 %) in 48 total cases ICH was seen in 17 cases (35.4 %) to be the most common region. 5. Among 35 persons, spontaneity CBR was the highest region of injury, 13 cases(37.1 %) ; the side of paralysis in extremities the right side showed higher incidence, 18 cas (1.4 %) as compared to the left, 16 cases(45.7%). In the case of traumatic injury, CBR was the highest region of injury, 4(30.8% )in 13 cases and as for the paralysis side, right side showed higher incidence 7 cases(53.8%) as compared to the left side 5 cases(38.5%). 6. In respect to recurrence, HBP was seen in 5 cases to be the most common cause, and as for the region of injury, CBR was the highest. 7. A period of rehabilitation therapy in the cases of physical therapy the highest term was 1-2 month, 14 persons(29.2%). As for occupational therapy within 2 week-term was the highest, 24 persons(50%). 8. Physical strenth grade M.T in the cases of the upper extrimities before therapy, the low mark(grade 0) was 30 cases(62.5%), compared to the high mark(above grade 3)seen in 1 case(2.1%), And after therapy, the lowest mark(grade 0)was seen in 5 cases(10.4%) where as the high mark(above grade 3)was seen in 29 cases(60.4%). In the case of the lower extremities before therapy, the mark(below grade 1)was 37 cases(77.1 %), while the high mark(above grade 3)was seen n 4 cases(8.4%). And after therapy the low mark(below grade 1)was seen in 5 cases (10.4 %) and the high mark (above grade 3)was seen in 29 cases(60.4 %). 9. Before therapy conigtive function-level evaluation utilized R.L.A.L, the low mark(below level 3)was seen in 9 cases(18.8%), while the high mark(above level 7)was seen in 18 cases(37.5%). And after therapy the low mark (below level 3)was 4 cases(8.3%) and high mark(above level 7)was seen in 38 cases(79%). 10. After rehabilitation therapy, patients who were able to walk independently were 29 persons(60.4%), among which 16 cases(55.2%) depended on cane. The ratio between the cases who were able to walk and unable to walk was 1.5:1.

  • PDF

Assessment of Liquefaction Potential Using Correlation between Shear Wave Velocity and Normalized LPI on Urban Areas of Seoul and Gyeongju (정규화LPI와 전단파 속도의 상관관계를 활용한 서울과 경주 지역 액상화 위험도 평가)

  • Song, Young Woo;Chung, Choong Ki;Park, Ka Hyun;Kim, Min Gi
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.38 no.2
    • /
    • pp.357-367
    • /
    • 2018
  • Recent earthquakes in Gyeongju and Pohang have raised interest in liquefaction in South Korea. Liquefaction, which is a phenomenon that excessive pore pressure is generated and the shear strength of soil is decreased by repeated loads such as earthquakes, causes severe problems such as ground subsidence and overturning of structures. Therefore, it is necessary to identify and prepare for the possibility of liquefaction in advance. In general, the possibility of liquefaction is quantitatively assessed using the Liquefaction Potential Index (LPI), but it takes a lot of time and effort for performing site response analysis which is essential for the liquefaction evaluation. In this study, a simple method to evaluate the liquefaction potential without executing the site response analysis in a downtown area with a lot of borehole data was proposed. In this simple method, the correlation between the average shear wave velocity of the target location ground and the LPI divided by thickness of liquefiable layer was established. And the applicable correlation equation for various rock outcrop accelerations were derived. Using the 104 boreholes information in Seoul, the correlation equation between LPI and the shear wave velocity (ground water level: 0m, 1m, 2m, 3m) is obtained and the possibility of liquefaction occurrence in Seoul and Gyeongju is evaluated. The applicability of the proposed simple method was verified by comparing the LPI values calculated from the correlation equation and the LPI values derived using the existing site response analysis. Finally, the distribution map of LPI calculated from the correlation was drawn using Kriging, a geostatistical technique.

Estimation of Genetic Parameter for Linear Type Traits in Holstein Dairy Cattle in Korea (Holstein종 젖소의 선형심사형질에 대한 유전모수추정)

  • Lee, Ki-Hwan;Sang, Byung-Chan;Nam, Myoung-Soo;Do, Chang-Hee;Choi, Jae-Gwan;Cho, Kawng-Hyun
    • Journal of Animal Science and Technology
    • /
    • v.51 no.5
    • /
    • pp.345-352
    • /
    • 2009
  • This study utilized 332,625 records of linear type scores consisting for 15 primary traits, 22,175 final score and 84,612 pedigree information of 22,175 Holstein cows from 1993 to 2007 in Korea to estimate genetic parameters for 16 type traits. Genetic and error (co)variances between two traits selected from 16 traits were estimated using bi-trait pairwise analyses with DFREML package. The estimated heritabilities for stature (ST), strength (STR), body depth (BD), dairy form (DF), rump angle (RA), thurl width (TW), rear legs side view (RLSV), foot angle (FA), fore udder attachment (FUA), rear udder height (RUH), rear udder width (RUW), udder cleft (UC), udder depth (UD), front teat placement (FTP), front teat length (FTL) and final score (FS) were 0.31, 0.21, 0.25, 0.10, 0.29, 0.19, 0.09, 0.06, 0.12, 0.13, 0.12, 0.08, 0.26, 0.20, 0.28 and 0.15, respectively. ST had the highest positive genetic correlation with BD (0.90), while RLSV had the highest negative genetic correlation with FA (-0.56). RA had negative genetic correlation with most udder traits (-0.17~-0.02). Especially, RUW had the higher positive genetic correlation with STR (0.60), BD (0.62), and TW (0.49), however, UD had the higher negative genetic correlation with STR (-0.40) and BD (-0.40). FTL had negative genetic correlation with FUA, RUH, RUW, UC and UD. FS had positive genetic correlation with UC, UD and FTP (0.12, 0.18 and 0.20). However, additional research is needed on the use of these parameters in the genetic evaluation because estimated genetic and error variance-covariance matrices were not positive definite.

Effect of Cryoprotectants on Quality Properties of Chicken Breast Surimi (냉동변성방지제의 종류가 닭가슴살 수리미의 품질 특성에 미치는 영향)

  • Jin, S.K.;Kim, I.S.;Kim, S.J.;Jeong, K.J.;Lee, J.R.;Choi, Y.J.
    • Journal of Animal Science and Technology
    • /
    • v.49 no.6
    • /
    • pp.847-856
    • /
    • 2007
  • This study was conducted to determine the effect of cryoprotectants(sugar, sorbitol, polyphosphate) on quality properties of chicken breast surimi manufactured by pH adjustment(pH 11.0) during frozen storage. Final surimi was divided into experimental units to which the following treatments were randomly assigned: C(Alaska pollack surimi, two times washing, 4% sugar+5% sorbitol+0.3% polyphosphate additive); T1(chicken breast surimi, 0.3% polyphosphate additive); T2(chicken breast surimi, 5% sorbitol +0.3% polyphosphate additive); T3(chicken breast surimi, 4% sugar+5% sorbitol+0.3% polyphosphate additive). All amino acid contents of control were higher than those of all treatments, while T2 was higher in amino acid contents among the treatments. Shear force of all treatments were higher than that of control, but the breaking force, deformation and gel strength were lower. The TBARS(thiobarbituric acid reactive substances) and VBN(volatile basic nitrogen) values of all treatments were lower than those of control, The TBARS values of all treatments were increased with increased storage period. In sensory evaluation, the score of appearance, meat color and overall acceptability of control were higher than those of all treatments, but aroma, juiciness and tenderness were lower than those for all treatments.

Evaluation of Construction Operation and Design Properties of CLSM for Corrugated Pipe in Underground (파형강관을 이용한 지하매설물용 뒤채움재 설계 및 시공성 평가)

  • Lee Kwan-Ho;Park Jae-Heon
    • International Journal of Highway Engineering
    • /
    • v.8 no.2 s.28
    • /
    • pp.63-74
    • /
    • 2006
  • During the construction of circular underground pipe, the non-proper compaction along the pipe and the decrease of compaction efficiency have been the main problems to induce the failure of underground pipe or facility. The use of CLSM (controlled low strength materials) should be one of the possible applications to overcome those problems. In this research, the full-scaled field test and the numeric analysis using PENTAGON-3D FEM program were carried out for three different cases on the change of backfill materials, including the common sand, the soil from construction site, and the CLSM. From the full-scaled test in field, the use of in-situ CLSM as backfill materials reduced the vertical and lateral deformation of the pipe, as well as the deformation of the ground surface. The main reason for reducing the deformation would be the characteristics of the CLSM, especially self-leveling and self-hardening properties. The measured earth pressure at the surround of the corrugated pipe using the CLSM backfills was the smaller than the other cases, and the absolute value was almost zero. Judging from the full-scaled field test and FEM analysis, the use of CLSM as backfill materials should be one of the best choices reducing the failure of the underground pipes.

  • PDF