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        검색결과 459

        22.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The characteristics of pollutant emission for non-premixed flames with LCG 8000 and LCG 6000 represented as low calorific gases were investigated by numerical simulation. Commercial software (ANSYS 16.2 - FLUENT) is used to predict 2-D pollutant emission with GRI 3.0 detailed reaction mechanism. In addition, the addition of hydrogen to LCG 6000 was also considered. As result, the flame length and temperature of LHVGs were decreased with decreasing calorific value at the same condition. In addition, NO concentration was decreased as temperature decreased. However, CO concentration for LCG 8000 predicted to be slightly higher than that for methane due to the high propane concentration. In the case of LCG 6000 with added hydrogen, the flame length was the shortest and NO concentration was the highest due to the highest flame temperature, but CO concentration decreased rapidly due to the addition of the carbon-free fuel.
        4,000원
        23.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2021년 우리나라 성범죄 발생은 6,321건, 범죄률 13.5%로 교정시설에서는 성범죄 예방을 위해 다양한 프로그램을 운영하고 있지만, 여전히 성범죄의 재범률은 증가하 고 있다. 그래서 본 연구에서는 변증법적 행동 치료이론을 기반으로 성범죄자의 재범 예방 프로그램을 개발하고자 한다. 프로그램의 개발은 선행연구와 요구조사를 바탕으 로 하였다. 프로그램은 변증법적 행동치료(DBT)의 4가지 핵심기술인 마음 챙김, 정서 조절훈련, 고통 감내, 대인 관계 증진 기술로 구성하였다. 연구설계는 비동등성 대조 군 사전-사후 설계(Nonequivalent control group pretest-posttest design)로 혼 합연구 방법(Mixed Methods Design)으로 프로그램의 효과를 검증하였다. 연구대상 자는 G*Power 3.1 program의 표본 크기에 맞게 G시 교정시설에 수감 된 남성 성범 죄자 중에서 총 28명 선정하고, 무작위 할당 표집으로 실험집단 14명과 대조집단 14 명으로 배정하였다. 하지만 이감과 중도 연구 참여 거부로 인한 탈락자를 뺀 실험집단 13명과 대조 집단 12명의 자료를 최종분석하였다. 양적 분석은 SPSS 27.0 프로그램 독립표본 검증(Independent t-test)으로 동질성을 확보를 확인하고, 집단 간 변화를 이원 혼합설계 반복측정 변량분석(Repeated measures ANOVA)으로 살펴보았다. 질적 자료는 Braun과 Clark(2006)가 제시한 주제 분석방법으로 분석하였다. 연구 결 과는 다음과 같다. 첫째, 변증법적 행동치료 프로그램에 참여한 실험집단이 대조집단 보다 대인 간의 공감 반응과 성인 애착에서 통계적으로 유의미하였으며, 변화의 효과 는 추후검사에서도 통계적으로 유의미하게 유지되었다. 둘째, 프로그램 참여 경험을 분석한 결과 36개의 하위 주제, 몇10개의 상위 주제가 나타났다. 이를 분석영역인 충 동성, 공격성, 자기통제력에 재배열하였다. 충동성에서는 이성에의 의지 폭력 행동의 자발적 제어, 예측 능력의 강화, 분노의 원인 탐색 주제가 돌출되었다. 공격성에서는 파괴 본능을 건강한 에너지로 전환, 타인에 대한 적대적 감정 없애기, 낮은 자리에 서 기라는 주제가 출연했다. 자기통제력에서는 유혹을 이길 수 있는 힘의 배양, 현재의 만족보다는 미래의 성공, 규범적인 행동 목표설정이 나타났다. 연구자들은 연구 결과에 근거하여 논의하였고, 교정기관 내에서 성범죄자들의 사회 재적응을 지지할 수 있는 실천적 접근을 제안함으로써 재범을 예방하고자 하였다. 본 연구는 기존의 교정시설 에서 시도하지 않은 변증법적 행동 치료이론을 접목한 프로그램의 개발하였기에 성범 죄자 프로그램에 새로운 패러다임을 시도하였다는 점에서 선행연구들과 차이가 있다.
        8,700원
        24.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to analyze the significance of binder aging in a hot-mix asphalt (HMA) mixture in an insulated camber for a long duration for repair works, where the absolute viscosity level and service life reduction (SLR) are assessed based on the haul time, as well as to suggest a methodology for reducing the aging level. METHODS : Because the HMA mixture is stored in an insulated box carriage at high temperature for repair works, if the binder in the mix is severely oxidized, then the repaired pavement will not exhibit a long service life. Therefore, the 13-mm dense-graded HMA mix with PG64-22 was aged in an oven at 160 °C for 1, 2, 4 and 8 h to evaluate its aging level. Gel-permeation chromatography was performed on the mixture particle without binder recovery to measure the large-molecular size ratio, from which the estimated absolute viscosity (EAV) was computed using a best-fit regression model. The SLR values of aged and repaired mixes were estimated to determine the amount of deterioration in the mixes caused by severe aging. Hydrated lime (HL) was introduced into the mix at a ratio of 1.5 wt% of the total mix. The aging level and SLR were compared with those of the repaired mix without HL. RESULTS : The binder EAV of the HMA mix increases significantly with the mixture aging duration. In particular, the binder EAV level of a 4-h aged mix is similar to the asphalt viscosity level of a pavement with approximately 7 years of service life. The service life expressed based on the aging level is interpreted as the reduced service life of the aged mix, which is already oxidized before it is used. Meanwhile, the binder of an 8-h aged mix without HL aged significantly and its SLR is approximately 11 years. However, its aging level and SLR reduced significantly when HL. is incorporated. CONCLUSIONS : The binder aging level of the repaired mix increases significantly with its storage duration in a hot chamber for carriage. However, since the aging level decreases significantly by the incorporation of HL, the use of HL is highly recommended when preparing new mix for repair works to be performed in a hot-chamber for a long duration.
        4,000원
        27.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the quality characteristics and antioxidant properties of fruit and vegetable jellies mixed with Boswellia. Jellies were prepared with 0, 2, 4, 6, and 8% Boswellia, sugar and konjac. As a result, the pH of Boswellia jellies decreased to 5.19, 5.05, 4.94, and 4.84, respectively (p<0.001). Their L-value, a-value, b-value, and hardness increased significantly with increasing levels of added Boswellia (p<0.001), while individual phenolic compounds increased significantly with increasing levels of added Boswellia. Free sugars and organic acid contents had the highest bw10. The total phenolic compounds had the highest BW5 (112.9 mg TAE/g), BW10 (99.41 mg TAE/ g), and while the ABTS activities showed higher values than the control group. Overall, Boswellia can be used to produce high-quality jelly, which is expected to help develop excellent functional jelly products.
        4,000원
        28.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study was to reduce greenhouse gases and prevent potholes on roads by evaluating the performances of hot and warm mixed asphalt mixtures. METHODS : Quality tests were conducted using an appropriate aggregate ratio of the asphalt mixture. The tests for comparing the warm mixed asphalt mixture are the indirect tensile strength and toughness, Marshall stability and flow, tensile strength ratio, and dynamic immersion test. A performance evaluation was conducted using a mixture that satisfied the quality test results. A performance evaluation test was also conducted using the dynamic modulus and Hamburg wheel tracking test. To analyze the performance based on the amine content, the performance was compared with that of a hot mixed asphalt mixture. RESULTS : All tests for the mixture results satisfied the standard values. The optimal amine content was analyzed through the high and low frequencies of the dynamic modulus test results and stripping inflection point with the final rut depth of the Hamburg wheel tracking test. The dynamic modulus test results demonstrated better crack resistance and plastic deformation when a high amine content ratio was used. The Hamburg wheel-tracking test showed water resistance and plastic deformation resistance. The test results of the Hamburg wheel tracking indicated better deformation resistance and water resistance when a high amine content ratio was used. CONCLUSIONS : The plastic deformation and crack resistance increased with an increase in amine content. Analysis of the comprehensive test revealed that the optimal amine content was between that of additives B(50%) and C(65%). Tests with a granular amine content are planned to confirm the specific components. Also planned are a simplified viscoelastic continuum damage test and a semicircular bending test to evaluate the performance better.
        4,000원
        29.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Preventive pavement maintenance is an economical and efficient method of infrastructure management. This study aims to improve the performance of cold thin-layer asphalt pavement, which is mainly used in earthwork pavement, and for bridge overlays and structures. METHODS : A cold asphalt mixture of modified emulsified asphalt and RAP was prepared for cold recycled thin-layer asphalt pavement. The performance of the mixture as a function of fiber reinforcement to improve flexural strength and crack resistance was evaluated. RESULTS : The use of RAP aggregate in cold asphalt mixture was found to increase the cohesive strength of the mixture and improve the wet abrasion resistance due to the effect of the residual binder. As a result of the loaded wheel test and flexural tension test with the addition of fiber reinforcement, it was found that the crack resistance of 0.4 % glass fiber was the best, and especially, the flexibility at low temperature was excellent. CONCLUSIONS : The cold recycled thin-layer asphalt pavement mixture has improved cohesive strength, flexural strength, and crack resistance compared to existing cold asphalt pavement materials, so it will contribute to economical and effective maintenance in preventive maintenance of bridge overlays and structural pavements.
        4,000원
        30.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Various kinds of friction materials were manufactured by adding 10%, 20%, and 30% of reduced iron, respectively, which has been obtained during the reduction process of blast furnace sludge extracted from the blast furnace, and its iron oxide, instead of existing barium sulfate(BaSO4) among the components of automobile brake friction materials. Fundamental physical property test and friction performance test, etc., using a brake dynamometer were carried out against these friction materials. Furthermore, when the expensive filling material, BaSO4 was substituted by reduced iron and added to the friction material, the added content of reduced iron for an excellent friction characteristic considering the heat emission temperature, wear, etc., was 10%. In the fundamental physical property test, as the added content of blast furnace sludge or reduced iron increased, and as the content increased, the shear strength and bonding strength of friction materials decreased, but both of them indicated sufficient strengths to be applied to a friction material. Even in the frictional performance test using a brake dynamometer, as the added content of blast furnace sludge or reduced iron increased, the friction coefficient reacted insensibly to brake deceleration, and its stability was improved.
        4,000원
        31.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study compared the performance evaluation of a hot mix asphalt (HMA) and asphalt mixture of a warm-antistrip agent. METHODS : A mix design applying Korean standards was conducted to evaluate the performance evaluation. Thereafter, the quality standard evaluation of the asphalt mixture produced was conducted, and if all quality standards were satisfied, a performance evaluation was conducted. Types of performance evaluation included the Hamburg wheel tracking test and dynamic modulus test. RESULTS : As a result of the Hamburg wheel tracking test, the asphalt mixture with a warm-antistrip agent obtained a lower sedimentation value at 10000 times and 20000 times. This result is considered to have higher plastic deformation resistance of the asphalt mixture with a Warm-antistrip agent than HMA. The U.S. Department of Transportation stipulates that plastic deformation resistance is excellent if the asphalt mixture does not exceed 20,000 times the precipitate of 20 mm. Therefore, we confirmed that the plastic deformation resistance of the asphalt mixture with a warm-antistrip agent was excellent. Additionally, the master curve was analyzed by synthesizing the results of the dynamic modulus test. When analyzing the low load cycle at the bottom left of the master curve, the dynamic modulus value of the master curve was higher in the asphalt mixture with a warm-antistrip agent than in the HMA. In addition, when analyzing the high load cycle part, the dynamic modulus of the HMA was measured to be higher than that of the asphalt mixture with a warm-antistrip agent. Accordingly, the resistance to fatigue cracking of the asphalt mixture with a warm-antistrip agent was considered superior to that of the HMA. CONCLUSIONS : As a result, we confirmed that the asphalt mixture with a warm-antistrip agent that satisfies the Korean quality standards had better plastic deformation and fatigue resistance for all performance evaluation tests conducted in this study than the HMA. However, since the Hamburg wheel tracking test did not significantly differ in the amount of sedimentation in the performance evaluation tests and the mixture using one additive was compared with HMA, studies on the effects of various additives containing warm-antistrip agents are required.
        4,000원
        34.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed the quality characteristics and antioxidant activity of a mixture of apple and carrot juices with different amounts of beet. The pH of the mixed juice sample group increased as the beet amount increased, and the acidity and soluble solid content tended to decrease. As for the L value, the control group was the highest, the beet addition rate decreased, and the a value and b value showed a decreasing trend. As for dietary fiber, B0.1 was found to have the highest dietary fiber content at 0.20 mg/L. As for the mineral, Zn, Fe, and Ca had the highest control group, Mn, Mg, and K had the highest B0.5, and Na and P had the highest B0.1 and B0.3 juices, respectively. Compared to the control group, free sugars increased sucrose as the beet juice added increased. DPPH radical scavenging and total phenol content significantly increased DPPH scavenging as the beet added increased. Therefore, it was found that B0.3 was the most suitable when manufacturing apple and carrot mixed juice with different amounts of beet added, and it is considered as a manufacturing optimization method to improve the marketability and functionality of the product.
        4,000원
        35.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 비건 인증(Vegan) 화장품 원료 7종 혼합추출물의 항산화능 및 미백효과를 확인 하였다. 라디컬 소거능으로서 DPPH, ABTS, FRAP 실험, 항산화 물질 측정으로서 폴리페놀과 플라보노이 드 함량 측정을 실시하였다. DPPH 실험에서는 105.74 mg ascorbic acid / g의 항산화능을 나타내었으며, ABTS 실험에서는 85.31 mg ascorbic acid / g의 항산화능을 나타내었다. FRAP에서는 7종 혼합추출물의 1 mg이 ascorbic acid 198.01±5.50 μg의 환원력을 보였다. 폴리페놀 함량은 30.19±0.75 mg/g으로 나타 났으며, 플라보노이드 함량은 9.12±0.36 mg/g으로 나타났다. 한편 세포실험에서는 세포 독성과 미백활성 을 알아보았다. 세포독성의 경우 20% 이하의 세포 독성을 보였으며, 100 μg/mL 농도에서 34.70±2.97% 의 멜라닌 생성 억제능을 보여 7종 혼합추출물의 기능성 화장품 원료로서의 가능성을 확인하였다.
        4,000원
        36.
        2022.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        코로나19는 우리나라 고등교육이 지향하던 미래교육에로의 변화를 앞당겨 경험하게 만들었다. 이론 교 과목 수업은 대부분 온라인으로 운영되었고 실험·실습·실기 교과목은 수강인원을 최소화하여 대면수업을 실시했으며 이론과 실습이 혼재된 교과목 수업은 두 가지 방법을 병행하는 방식으로 진행되었다. 대변혁 의 과정에서 대학교육 정책 수립 및 교육과정 운영자들의 관심이 혼합수업 만족도 제고 방안 모색에 집중 되고 있다. 수도권 S대학에서 교육 정책 및 운영 등 대학교육의 수업 질 관리 차원에서 교육혁신을 주도했던 관련 자들의 포괄적 업무수행이 연구의 기반이 되었다. 코로나19 이후 확대된 대학 자율권을 바탕으로 새로운 정책의 입안과 실행 그리고 평가 과정을 통해서 유의미한 성과가 확인되었고, 그 성과는 통계적으로 검증 되었다. 수도권 S대학에서는 학생 디지털학습역량과 학생-교수 간 상호작용이 수업만족도와 관련이 있다 는 것을 확인한 후 이러한 변수를 통제한 상태에서 수업만족도에 영향을 주는 새로운 변인을 탐색하였다. 본 연구는 수도권 S대학의 각 교과목 유형별로 학생들의 디지털 학습역량과 학생-교수 간 상호작용을 통제한 상황에서 대학의 두 가지 운영방안이 혼합수업 만족도에 영향을 미치는가를 검증하였다. 첫 번째 방안은 각 학생이 수강하지 않는 교과목에 관한 강의동영상을 활용하여 스스로 학습할 수 있도록 하는 것이었고, 두 번째 방안은 기 실시된 대면수업을 정리·요약한 수업요약 동영상을 제작하여 수강생들에게 제공하는 것이었다. 연구결과 이론, 이론+실습, 실험·실습·실기 등 모든 범주의 교과목 유형에서 두 방안 은 수업만족도에 대하여 유의미한 관련성이 있음이 확인되었다. 다만 세 가지 수업형태별 범주에 따라서 새로운 수업 운영방안의 수업만족도에 대한 상대적 중요도가 일치하진 않았다. 고등교육에서 혼합교육 시대의 수업만족도를 제고할 수 있는 또 다른 변인을 찾는 후속 연구가 지속되 어야 한다.
        6,000원
        37.
        2021.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 겉보리를 고체 기질로 사용하여 액체발효(LSF)와 고 체발효(SSF)를 수행하였으며, 또한 겉보리의 발아(germination) 에 따른 SSF 및 A. oryzae NIBRFGC000501965와 A. pullulans KCCM60122의 혼합발효를 통해 효소 및 β-glucan 생산에 대한 고체발효 연구를 수행하였다. 이러한 연구결과들은 기존의 고체발 효법에서 효소 및 β-glucan 생산에 있어 효율적인 발효공정의 기 초자료로 유용한 정보를 제공할 것으로 판단된다.
        4,000원
        38.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to identify a gradation control method that minimizes the volatility of recycled aggregates to maintain the quality of reclaimed asphalt mixtures. METHODS : In this study, two types (0~13 and 0~10 mm) of recycled aggregate stockpiles with an extraction viscosity of 40,000 poise and a 19 mm hot asphalt mixture with virgin aggregates are used. The test methods are evaluated for plastic deformation resistance using the Hamburg wheel-tracking test and for low-temperature crack resistance using the dynamic modulus test. In the field, the performance is evaluated via an accelerated pavement test. RESULTS : The Hamburg wheel-tracking test shows good water resistance as well as less than 5 mm of deformation. The result of a dynamic modulus test at -5 °C shows a 92.9% low-temperature crack resistance as compared with that of the 19 mm dense grade hot-mix asphalt mixture. The result of the accelerated pavement test confirms that the performances of the 19 mm dense grade hot-mix asphalt mixture and reclaimed asphalt mixture are equal owing a 1.2 cm plastic deformation. CONCLUSIONS : By evaluating the plastic deformation resistance and crack resistance of the reclaimed asphalt mixture based on a stockpile gradation controlled at 0~10 mm via an indoor test, it is discovered that the plastic deformation resistance increases partially, whereas the crack resistance remains almost unchanged. The accelerated pavement test confirms that a performance equivalent to that of a 19 mm dense grade hot-mix asphalt mixture is achieved.
        4,000원
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