• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.11-18
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• 2012

This paper deals with the numerical determination of the stress intensity factors of cracked aluminum plates under the mixed mode of $K_I$ and $K_{II}$ in glass-epoxy fiber reinforced composites. For the stress intensity factors, two different models are reviewed such as VCCT and two-step extension method. The p-convergent partial layerwise model is adopted to determine the fracture parameters in terms of energy release rates and stress intensity factors. The p-convergent approach is based on the concept of subparametric element. In assumed displacement field, strain-displacement relations and 3-D constitutive equations of a layer are obtained by combination of 2-D and 1-D higher-order shape functions. In the elements, Lobatto shape functions and Gauss-Lobatto technique are employed to interpolate displacement fields and to implement numerical quadrature. Using the models and techniques considered, effects of composite laminate configuration according to inclined angles and adhesive properties on the performance of bonded composite patch are investigated. In addition to these, the out-of-plane bending effect has been investigated across the thickness of patch repaired laminate plates due to the change of neutral axis. The present model provides accuracy and simplicity in terms of stress intensity factors, stress distribution, number of degrees of freedom, and energy release rates as compared with previous works in literatures.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.679-685
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• 2010

Many animal models of osteoarthritis (OA) have been developed, aimed at understanding the long-term progression of OA and difficulty of identifying patients in the initial stage of the disease. In canines, coxofemoral luxation and hip dysplasia are common orthopedic ailments related to OA in the hip joint. Transecting the ligament of the head of the femur (LHF) aids in diagnosis of coxofemoral joint OA. Presently, mobility of this joint was increased by transected LHF in 10 mature, 2-3-year-old (average $2.57{\pm}0.20$ years), healthy male beagles. The animals were normally gaited 1-week post-operatively. During the experimental period, examinations including X-ray, complete blood count and serum chemistry were unremarkable. Proteomic examination revealed protein alterations in synovial fluid, with significant increases in Vitamin D-binding protein precursor (ANOVA, p < 0.004) and Kinogen-1 (ANOVA, p < 0.039). Both proteins correlated with arthritis.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.589-596
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• 2018

Purpose : We compared intraocular pressure (IOP) values measured by two types of tonometers in condition of normotensive and glaucomatous rat model. We tried to determine which of tonometer can more easily and accurately measure the IOP of animal model. Methods : Glaucomatous eyes were induced by intracameral injections of hyaluronic acid in right eyes of six-week-old male Spargue-Dawley (SD) rats. Normotensive contralateral eyes were left eyes of the SD rats. IOP was measured using a rebound tonometer (Tonolab) and a immersive tonometer ($Tonopen^{(R)}$ XL) about 3:00 pm. Results : The mean IOP values of normotensive control eyes were $10.80{\pm}1.03mmHg$ by Tonopen, and $15.10{\pm}0.73mmHg$ by Tonolab. They were statistically insignificant (p = .1). The mean IOP values of glaucomatous experimental eyes were $30.20{\pm}2.67mmHg$ by Tonopen, and $37.90{\pm}2.73mmHg$ by Tonolab. They were statistically insignificant (p = .95). High IOP values of glaucomatous eyes by two types of tonometers had strong positive correlation each other (r = .904, p < .01). Conclusion : This is the first study to compare IOP values using two types of tonometers between normotensive and glaucomatous model made by intracameral injection of hyaluronic acid. Tonopen should be used carefully when the IOP is within normal range, and both Tonopen and Tonolab can be used reliably when the IOP is high.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.843-850
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• 1994

Polyphosphazene-bound Wittig reagents such as $[NP(OC_6H_5)_{1.7}(OC_6H_4P(Ph)_2$=$CHCH_2CH_2CH_3)_{0.3}]_n$ were synthesized by treating $[NP(OC_6H_5)_{1.7}(OC_6H_4Br)_{0.3}]_n$ with n-butyllithium, diphenylchlorophosphine, and n-butyl iodide. Polymeric reactions were carried out according to the reaction conditions with cyclic primers such as [$N_3P_3(OC_6H_5)_5(OC_6H_4P(Ph)_2$)]. The desired alkene and polymer-bound phosphine oxide were prepared successfully by the reaction of polyphosphazene-bound Wittig reagents with benzophenone.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.450-459
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• 2014

Crushed pinewood and oakwood were studied as an adsorbent for Pb(II) removal from aqueous solution. Batch adsorption experiments were carried out to describe the effects of contact time, initial Pb(II) concentration, pH, competing cations, and adsorbent dosage on the Pb(II) adsorption process. Kinetic studies revealed that the Pb(II) adsorption process for pinewood and oakwood followed both pseudo first and pseudo second order model. The Fruendlich model best described equilibrium adsorption data with correlation coefficients ($R^2$) of 0.956 and 0.950 for pinewood and oakwood. The maximum adsorption capacity of Pb(II) onto pinewood and oakwood was found to be 16.853 and 27.989 mg/g, respectively. The Pb(II) adsorption onto both pinewood and oakwood was increased as pH increased in the pH range 3-9. The presence of cations such as $Na^+$, $Ca^{2+}$, and $Al^{3+}$ decreased Pb(II) adsorption. The Pb(II) removal was greater in seawater than deionized water, resulting from the presence of $CO{_3}^{2-}$ and $OH^-$ ions in seawater. This study showed that pinewood and oakwood have a potential application in the remediation of Pb(II) contaminated water.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.249-253
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• 2003

강서구를 제외한 부산 전지역에서 1998년도에 조사된 지하수 수질 중 6개 성분(pH, TS, KMnO$_4$, Cl, SO$_4$, NO$_3$-N)에 대한 일반통계분석 결과 pH 성분을 제외하고는 5개 성분의 중앙값이 평균보다 적은 값을 보이는 양성왜도를 보임으로써, 수질오염정도를 분석하기 위해 지시크리깅이라는 비모수적인 지구통계분석기법을 적용하였다. 6개 수질성분에 대해 음용수 기준치를 적용하여 음용가능은 “1”의 값이, 음용불가능은 “0”의 값이 주어졌다. 이렇게 변환된 자료를 이용하여 각 성분별로 실험적인 베리오그램 분석을 실시한 결과 pH, TS, SO$_4$ 성분은 선형모델이 선정되었으며, KMnO$_4$, Cl, NO$_3$-N 성분은 구상형모델이 선정되었다. 본 연구에서는 지시크리깅을 이용하여 6개 성분의 분포도를 작성하고 부산지역의 오염정도를 분석하였다. 지시크리깅기법은 연구지역 전체의 정량적인 분포를 나타내지는 못하지만, 오염의 유.무와 오염의 크기를 정확하게 파악할 수 있으며 또한, 이상치(outlier)가 크게 영향을 미칠 수 있는 통계학적인 오류를 보완할 수 있다.

• The Korean Journal of Rehabilitation Nursing
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• v.13 no.2
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• pp.132-139
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• 2010

Purpose: The purpose of this study was to identify the types of family function and mental health in low-income middle aged women using the circumplex model. Method: A descriptive research design was used. A sample of 116 low income middle aged women participated in the study. The Family Adaptability and Cohesion Evaluation Scale III was used to measure the types of family function. Mental health was measured by the SCL. Results: The types of family function identified were balance family (59.4%), extreme family (25.9%), and mid-range family (14.7%). Significant differences were found in mental health by the family cohesion (F=3.44, p=.019) and family adaptability (F=3.31, p=.023). The mental health status of extreme family was better than mid-range family and balanced family, but such result was not statistically significant (F=0.25, p=.783). Conclusion: The Circumplex model's main hypothesis was not empirically supported that extreme family has more problematic than mid-range family and balance family. These findings emphasize the need for the development of a family system model for Korean family.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.421-421
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• 2019

본 연구의 목적은 HSPF 모델을 이용하여 비점오염물질이 수질에 미치는 영향을 평가하는 것이다. 합천댐 유역을 연구대상지역으로 선정하였으며, 입력자료는 유역도, 하천도, 토지이용도, 수치표고모델 및 기상자료 등을 이용하였다. HSPF 모형은 2000년부터 2016년까지의 실측값을 이용하여 보정 및 검증이 이루어졌다. 수문 보정을 위한 매개변수는 사용자 설명서와 참고문헌에 근거하여 선정하였으며, 시행착오법에 의해 수행되었다. 모델의 적용성 평가는 $R^2$, RMSE, RMAE, NSE를 사용하였고 $R^2$가 0.78에서 0.83, RMSE는 2.55에서 2.76mm/day, RMAE는 0.46에서 0.48mm/day, NSE는 0.81에서 0.82까지의 범위로 나타났으며, 연간 유출량이 ${\pm}4%$ 오차 이내로 산정되었다. 수질 모형을 구동하기 위한 수질 자료는 환경부에서 제시한 지침에 따라 생활계, 축산계, 산업계, 토지이용량에 따른 발생 부하량과 배출부하량을 산정하였다. 수질 모형 또한 수문과 같은 기간의 자료를 이용하여 보정 및 검정이 이루어졌다. 보정 결과 연평균 BOD의 차이가 0.22mg/L이고 오차범위는 13%였으며, T-N과 T-P는 0.66mg/L, 0.027mg/L의 차이를 가지며 오차범위는 각각 16%, 13%로 나타났다. 수질항목 중에서도 비점오염 관리의 효과를 평가하기 위해 비점오염물질 중 가장 큰 비중을 차지하는 축산계에 감소 시나리오를 적용하였다. 축산계의 배출부하량 감소율이 20%일때의 BOD, T-N, T-P는 각각 3%, 1%, 3% 감소하였으며 40% 감소율을 적용하였을때는 5%, 3%, 4% 감소하였다. 이러한 수질 해석을 결과를 토대로 효과적인 오염물질 방법을 적용하여 수질 개선과 합천댐 유역의 목표수질을 달성 할 수 있을 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.246-252
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• 2015

In steel factory, hot roller cleaning process produces a lot of iron oxide particles called as mill scale. Major components of these particles are wustite (FeO), magnetite ($Fe_3O_4$), and hematite ($Fe_2O_3$). In this study, we tried to produce pure magnetite from the mill scale because of the largest phosphate adsorption capacity of the magnetite. The mill scale was treated with acid (HCl+$H_2O_2$), base (NaOH), and acid-base ($H_2SO_4$+NaOH). Batch adsorption tests showed the acid and/or base treatment could increase the phosphate adsorption capacity of the iron oxides from 0.28 to over 3.11 mgP/g. Magnetite, which could be obtained by acid and base treatment of the mill scale, showed the best adsorption capacity. From the kinetic analysis, both Freundlich and Langmuir isotherm well described the phosphate adsorption behavior of the magnetite. In Langmuir model, maximum phosphate adsorption capacity was found to be 5.1 mgP/g at $20^{\circ}C$.

• Journal of Technologic Dentistry
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• v.41 no.4
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• pp.287-293
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• 2019

Purpose: To evaluate the accuracy of the 3D printed die models and to investigate its clinical applicability. Methods: Stone die models were fabricated from conventional impressions(stone die model; SDM, n=7). 3D virtual models obtained from the digital impressions were manufactured as a 3D printed die models using a 3D printer(3D printed die models;3DM, n=7). Reference model, stone die models and 3D printed die models were scanned with a reference scanner. All dies model dataset were superimposed with the reference model file by the "Best fit alignment" method using 3D analysis software. Statistical analysis was performed using the independent t-test and 2-way ANOVA (α=.05). Results: The RMS value of the 3D printed die model was significantly larger than the RMS value of the stone die model (P<.001). As a result of 2-way ANOVA, significant differences were found between the model group (P<.001) and the part (P<.001), and their interaction effects (P<.001). Conclusion: The 3D printed die model showed lower accuracy than the stone die model. Therefore, it is necessary to further improve the performance of 3D printer in order to apply the 3D printed model in prosthodontics.