PURPOSES : In this study, a fracture-based finite element (FE) model is proposed to evaluate the fracture behavior of fiber-reinforced asphalt (FRA) concrete under various interface conditions. METHODS: A fracture-based FE model was developed to simulate a double-edge notched tension (DENT) test. A cohesive zone model (CZM) and linear viscoelastic model were implemented to model the fracture behavior and viscous behavior of the FRA concrete, respectively. Three models were developed to characterize the behavior of interfacial bonding between the fiber reinforcement and surrounding materials. In the first model, the fracture property of the asphalt concrete was modified to study the effect of fiber reinforcement. In the second model, spring elements were used to simulated the fiber reinforcement. In the third method, bar and spring elements, based on a nonlinear bond-slip model, were used to simulate the fiber reinforcement and interfacial bonding conditions. The performance of the FRA in resisting crack development under various interfacial conditions was evaluated. RESULTS : The elastic modulus of the fibers was not sensitive to the behavior of the FRA in the DENT test before crack initiation. After crack development, the fracture resistance of the FRA was found to have enhanced considerably as the elastic modulus of the fibers increased from 450 MPa to 900 MPa. When the adhesion between the fibers and asphalt concrete was sufficiently high, the fiber reinforcement was effective. It means that the interfacial bonding conditions affect the fracture resistance of the FRA significantly. CONCLUSIONS: The bar/spring element models were more effective in representing the local behavior of the fibers and interfacial bonding than the fracture energy approach. The reinforcement effect is more significant after crack initiation, as the fibers can be pulled out sufficiently. Both the elastic modulus of the fiber reinforcement and the interfacial bonding were significant in controlling crack development in the FRA.

PURPOSES: A tack coat has been utilized to increase the bond performance between the surface layer and base course (intermediate course) at various road pavement sites. This is similarly true in other nations. Based on this connection, the objective of the present study is to evaluate the properties of hot mix asphalt (HMA) mixtures with an RSC-4 or BD-Coat and determine the application rate of the tack coat. METHODS: The HMA specimens were manufactured using superpave gyratory compaction. The HMA mixtures were composed of a 5-cm thick surface layer and a 10-cm thick base course. An impact hammer resonance test (IHRT) and a static load shear test were conducted to evaluate the performance of the HMA mixtures with a tack coat. From these tests, the dynamic moduli related to the high-frequency resistance and interlayer shear strength (ISS) of HMA could be obtained. RESULTS: The results of the dynamic moduli of HMA are discussed based on the resonance frequency (RF). To check the accuracy of the IHRT, we conducted a coherence analysis. A direct shear test using the application of a static load test was carried out to evaluate the interlayer shear strength (ISS) of HMA. CONCLUSIONS: The maximum ISS was demonstrated at an RSC-4 application rate of 462 gsm, and the maximum dynamic modulus was demonstrated at an RSC-4 application rate of 306 gsm. By averaging the results of the ISS, the maximum ISS values were obtained when a BD-Coat application rate of 602 gsm was applied.

The purpose of this study is to identify the flow resistance of the bottom pair trawl nets. The bottom pair trawl nets being used in fishing vessel (100G/T, 550ps) was selected as a full-scale net, and 1/10, 1/25 and 1/50 of the model nets were made. Converted into the full-scale net by Tauti’s modeling rule and Kim’s modeling rule, when resistance coefficient k of each net was calculated by substituting into above equation for flow resistance R and wall area of nets S values of each net v. Because resistant coefficient k decreases exponentially according as flow velocity v increases to make k cv-m, c and m values of each net were compared. As a result, as the model was smaller, c and m values was smaller in the two rule into standard of 1/10 model value, decrease degree of 1/25 model was almost same in the two rule, decrease degree of 1/50 model was very big in Tauti’s modeling rule. Therefore, in the result of experiment, because average of c and m values for similarly 1/10 and 1/25 model were given c=4.9 (kgf․s2/m4) and m=0.45, R (kgf) of bottom pair trawl net could show R =4.9Sv1.55 using these values. As in the order of cod-end, wing and bag part for 1/25 and 1/50 model net were removed in turn, measured flow resistance of each, converted into the full-scale, total resistance of the net and the resistance of each part net were calculated. The resistance ratio of each part for total net was not same in 1/25 and 1/50 model each other, but average of two nets was perfectly same area ratio of each part as the wing, bag and cod-end part was 43%, 45% and 12%. However, the resistance of each part divided area of the part, calculated the resistance of per unit area, wing and bag part were not big difference each other, while the resistance of cod-end part was very large.

Photovoltaic (PV) modules are environmentally energy conversion devices to generate electricity via photovoltaic effect of semiconductor from solar energy. One of key elements in PV modules is “backsheet,” a multilayered barrier film. A desirable backsheet should exhibit barrier properties. A representative backsheet materials is composed of polyvinyl fluoride (PVF) and poly(ethylene terephthalate) (PET). In this study, we utilize PET films with high crystallinity, instead of PVF. Since it is well known that PET is suffering from hydrolysis, it is needed to understand PET decomposition behavior. To evaluate their hydrolysis behavior, accelerated PET decomposition test protocols are used. Electro chemical PV module performances are investigated to prove the efficacy of hydrolyticall durable PET films selected via the screening process.

Perfluorinated sulfonic acid ionomers (PFSAs) have been used as cationic membrane materials for polymer electrolyte fuel cells, redox flow batteries. PFSAs exhibit high ionic conductivity and chemical toughness. Unfortunately, it is difficult to tune fundamental characteristics of commercially available PFSA membranes. On the other hand, protonated PFSA emulsion in water-alcohol mixture is useful in making modified PFSA membranes. The formation of the PFSA membranes, however, requires additional steps such as NaCl treatment, water treatment, and drying. These processes act as rate-determining steps for PFSA membrane fabrication. In this study, a simple salt conversion process is achieved in the PFSA emulsion. The process contributes to enhanced morphological transition and fast proton transport through the resulting membranes.

최근 전기전자산업이 급격하게 발전함에 따라 첨단소재로서 희소금속 및 유가금속의 용도가 다양해지고 수요가 급증하고 있다. 일반적으로 습식제련공정에서의 모액은 황산용액 상태이며, 모액중의 유가금속(Cu, Zn) 및 희소금속(In, Se, Re 등)은 보통 수 ppm에서 수 % 단위로 용해되어 있다. 종래에 방법들은 비용이 많이 들고 폐기물이 다량 발생하여 경제적이지 못한 반면 막분리 공정을 이용하면 친환경적이면서 효율적으로 회수할 수 있다는 장점이 있다. 본 연구에서는 내산성이 우수한 폴리아미드/실록산 블렌딩 나노여과막을 제조하고, 제조된 막의 구조적 특성 및 투과분리 특성에 대하여 살펴보았다. 그리고 제조된 분리막을 15 wt%의 황산용액에 대하여 내산성능평가를 진행하였다.

Compared to steel of the same weight in steel concrete structures, fiber reinforced polymer (FRP) is known to have greater strength and better resistance to corrosion. As such, it is being proposed as an effective structural material. Despite its many advantages, FRP has not been rapidly adopted in civil structures. This is because it is more expensive, prone to brittle fracture, and has weak fire resistance. To examine changes in the mechanical properties of FRP and the effectiveness of fire resistant coating, this study conducted tensile tests on coated and uncoated specimens over varying temperature. Glass fiber has excellent fire resistance since it does not melt or burn at high temperatures. However, epoxy is unable to withstand exposure to temperatures exceeding the transition temperature, thus leading to unsatisfactory structural performance and fire resistance. This study investigated the behavioral changes in FRP by exposing the specimens to temperatures ranging from room temperature (approx. 25℃) to 300℃, so as to improve the fire resistance of epoxy.

Transcriptome analysis was conducted for the identification of genes associated with insecticide resistance in Frankliniella occidentalis. Resistant strain (FO_RDAHC) exhibited 39.2- ~ 533-fold resistance to acrinathrin, spinosad, emmamectin benzoate and thiamethoxam compared with a susceptible FO_RDA strain. Average 7.6 million reads (± 5,068,895 reads) were obtained from the pyrosequencing and were assembled into the draft CDS database. Gene annotation was conducted by BLAST (UniProt), Pfam, FUNCAT and COG analysis. In the deferentially expressed gene (DEG) analysis, 838 genes were up-regulated and 815 genes were down-regulated over 2-fold ratio in FO_RDAHC strain. Highly up-regulated genes included genes encoding several cuticle-related proteins, cytochrome P450s, esterases and transporter genes. An autotransporter protein gene exhibited the highest up-regulation (596 fold) whereas a GMC oxido-reductase revealed the highest down-regulation (12 fold). Further study would be necessary to validate the actual transcript levels of DEGs and to investigate their functional roles in insecticide resistance.

Dow AgroSciences has a long history of proactive insecticide resistance management efforts. In our experience, the key to managing resistance is to reduce selection pressure on any one mode-of-action by convincing farmers to rotate among effective insecticide products with different modes of action and to use only the number of insecticide applications required for effective Integrated Pest Management (IPM). To accomplish this, farmers may need to use non-chemical control methods and to rotate to insecticide products that are effective but may not provide the highest levels of control. Integrating rotation of effective insecticides with other IPM techniques can provide high quality and quantity of the harvested crop. We will share our experience managing spinosyn resistance with a series of best management practices for western flower thrips (Frankliniella occidentalis Pergande) and our resistance management recommendations for ISOCLASTTM (sulfoxaflor), our new insecticide for control of sap-feeding insect pests. Dow AgroSciences is an active member of the IRAC (Insecticide Resistance Action Committee) and strongly supports the placement of IRAC mode-of-action group numbers on insecticide product labels. This simple approach greatly facilitates effective product rotation. Resistance management is critical to maintaining the effectiveness of the current arsenal of conventional insecticides and transgenic insect-resistant crops for as long as possible. Responsibility for resistance management is shared between manufacturers, formulator-distributors, retailers, influencers (universities, government), and farmers. It is up to all of us to make sure all stakeholders, and especially farmers, fully understand the benefits associated with insecticide resistance management (IRM) programs and the consequences associated with the resistance development in insect pest populations. ™ Trademark of The Dow Chemical Company ('DOW') or an affiliated company of Dow.

Tetranychus urticae was collected from greenhouse roses to monitor the development of acaricide resistance. Dose-mortality lines were estimated on 16 regional populations with 13 acaricides. For each acaricide, LC50s of the populations were plotted to check normality. LC50s of eight acaricides showed normal distribution and five others did not. An index of Ln (recommended dose/LC50 for each acaricide) checked the development of resistance to populations. The index is based upon recommended dose to control a pest stage and empirical LC50 got from serial dilution range for each pesticide. We tried to categorize acaricides by index due levels of effectiveness to mites: tebufenpyrad, fenpyroximate, bifenthrin, and fenbutatin oxide as non-effective acaricides with less than index 1.0, chlorpyrifor+bifenthrin and milbemectin as alert level placed between 1.0 and 2.0, acequincyl as caution between 2.0 and 3.0, and abamectin, cyflumetofen, bifenazate, chlorfenapyr+fulacrypyrim and propargite as effective over 3.0. We also tested the similarity of acaricide actions for choosing effective acaricides against resistant mites and of populations for resistance management. We could make several acaricides groups: group1 including abamectin, cyflumetofen, and bifenazate group 2 propargite and chlorpyrifos+bifenthrin group 3 chlorfenapyr and acequinocy and group 4 mibemectin, fenyroximate, and bifenthrin, by which we can suggest not to use acaricide within the same group to avoid the resistance development. Populations grouping would imply similar practices of acaricide use, so we can manage pesticide usage, effectively. Group A includes Gimhae 2, 3, 4, 5, Jincheon2, and Taean, and Group B includes Goyang, Gangjin1, Paju, Gangin2 and Namwon.

인간이 의도적으로 다른 생물들(병원균, 잡초, 곤충 등)의 개체수를 조절하고자 항생제, 제초제, 살충제 등의 약제를 사용하는 것은 필연적으로 이들 개체군 내에서 약제 내성의 진화가 일어나도록 한다. 진화생물학의 관점에서 약제 내성의 진화는 크게 “Evolutionary Rescue”라고 하는 최근 새롭게 대두되는 연구 분야의 결과를 적용하여 분석할 수 있다. 이는 환경의 급격한 변화 (즉, 인간에 의한 약제 투여/살포)에 따른 개체군 크기의 감소가 새로운 적응 (내성) 돌연변이의 출현에 의해 저지되어 개체군의 절멸을 저지하는 과정을 연구한다. 내성의 진화가 얼마나 빠른 속도로 일어나는가는, 조절하고자 하는 개체군의 인구학적 구조 (population structure and demography), 약제의 강도와 잔류농도 (drug dose and decay), 약제의 존재 유무에 따른 내성 돌연변이의 상대적 및 절대적 적응도 (relative and absolute fitness under the presence and absence of drugs), 아집단 간 개체의 이주율 (migration rate), 숙주의 저항/면역성 (host immunity), 저항성 획득의 분자생물학적 기작, 약제의 조합 (combination, mosaic, etc.) 등의 요인에 의해 결정된다. 본 발표에서는 이러한 요인들의 작용을 anti-malarial 내성 진화 모델의 구체적인 예를 통해 고찰할 것이다. 특히, 초기 내성 부여 돌연변이의 절대적 적응도 (absolute fitness)에 따라 내성 저지를 위한 두 가지의 극단적인 정책이 입안될 수 있다는 결론을 얻는다.

PURPOSES: The scaling of a concrete surface caused by the combined effects of frost and de-icing salts is one of the main reasons for the need to repair transportation infrastructures in cold-climate regions. This study describes the results of attempts to determine the scaling resistance of concrete incorporating mineral admixtures such as fly ash, GGBFS, and silica fume, and subjected to the actions of frost and salt. METHODS : Conventionally, to evaluate the fundamental properties of concrete, flexural and compressive strength measurements are regularly performed. Based on the ASTM C 672 standard, concrete is subjected to 2%, 4%, and 8% CaCl2 salt solutions along with repeated sets of 50 freeze/thaw cycles,and the scaling resistance was evaluated based on the mass of the scale and a visual examination. RESULTS : It was observed that silica fume is very effective in enhancing the scaling resistance of concrete. Meanwhile, concrete incorporating GGBFS exhibited poor resistance to scaling, especially in the first ten freeze/thaw cycles. However, fly ash concrete generally exhibited the maximum amount of damage as a result of the frost-salt attack, regardless of the concentrations of the solutions. CONCLUSIONS: It can be concluded that the scaling resistance of concrete is highly dependent on the type of the mineral admixture used in the concrete. Therefore, to provide a durable concrete pavement for use in cold-climate regions, the selection of a suitable binder is essential.

청보리 신품종 '녹양'은 총체생산성이 높고 생육후기 녹체성이 우수하며, 도복에 강하고 보리호위축병에 저항성인 품종이다. 이 품종은 2001년 '낙영'을 모본, 육성계통인 'SB77368-B-145'를 부본으로 교배하여 선발된 'SB01T2017-B-B-1-2' 계통을 2007년~2012년까지 관찰시험, 생산력검정시험과 지역적응시험을 거쳐 2012년에 육성되었다. '녹양'은 반포복 초형으로 파성이 III 정도이며, 잎은 담녹색이면서 넓고, 줄기 굵기는 중간 정도이며, 이삭은 길고 까락은 일반망이다. '녹양'은 잎과 줄기의 후기녹체성이 '영양'에 비해 오래 지속되었다. '녹양'의 초장은 104 cm로 대비품종인 '영양'에 비해 장간형이고, 평균 출수기와 성숙기는 각각 5월 6일과 6월 4일로 '영양'보다 늦었다. '녹양'은 '영양'보다 추위와 도복에 강하였고, 보리호위축병에 대하여 익산(III형), 나주(I형), 진주(IV) 등 모든 지역에서 저항성을 보였다. '녹양'의 평균 건물수량은 전작에서 12.8톤/ha, 답리작에서 11.5톤/ha으로 영양'에 비하여 각각 7%, 2% 증수하였다. '녹양'과 '영양' 모두 황숙기에 곡실의 탈립 정도가 매우 낮았고, 조사료 품질은 조단백질 함량 7.2%, ADF 25.9%, TDN 68.5%로 '영양'과 대등하였고, 젖산함량도 3.36%로 3.04%인 '영양'과 비슷하였으며, 사일리지 등급은 2등급으로 양호하였다.

청보리 신품종 ‘녹양’은 총체생산성이 높고 생육후기 녹체성이 우수하며, 도복에 강하고 보리호위축병에 저항성 인 품종이다. 이 품종은 2001년 ‘낙영’을 모본, 육성계통인 ‘SB77368-B-145’를 부본으로 교배하여 선발된 ‘SB01T2017- B-B-1-2’ 계통을 2007년～2012년까지 관찰시험, 생산력검정 시험과 지역적응시험을 거쳐 2012년에 육성되었다. ‘녹양’ 은 반포복 초형으로 파성이 Ⅲ 정도이며, 잎은 담녹색이면 서 넓고, 줄기 굵기는 중간 정도이며, 이삭은 길고 까락은 일반망이다. ‘녹양’은 잎과 줄기의 후기녹체성이 ‘영양’에 비해 오래 지속되었다. ‘녹양’의 초장은 104 cm로 대비품종 인 ‘영양’에 비해 장간형이고, 평균 출수기와 성숙기는 각 각 5월 6일과 6월 4일로 ‘영양’보다 늦었다. ‘녹양’은 ‘영 양’보다 추위와 도복에 강하였고, 보리호위축병에 대하여 익산(Ⅲ형), 나주(Ⅰ형), 진주(Ⅳ) 등 모든 지역에서 저항성 을 보였다. ‘녹양’의 평균 건물수량은 전작에서 12.8톤/ha, 답리작에서 11.5톤/ha으로 영양’에 비하여 각각 7%, 2% 증수하였다. ‘녹양’과 ‘영양’ 모두 황숙기에 곡실의 탈립 정 도가 매우 낮았고, 조사료 품질은 조단백질 함량 7.2%, ADF 25.9%, TDN 68.5%로 ‘영양’과 대등하였고, 젖산함량 도 3.36%로 3.04%인 ‘영양’과 비슷하였으며, 사일리지 등 급은 2등급으로 양호하였다.

In this paper, a finite element dynamic simulation study was performed to gain an insight about the blast wall test details for the offshore structures. The simulation was verified using qualitative and quantitative comparisons for different materials. Based on in-depth examination of blast simulation recordings, dynamic behaviors occurred in the blast wall against the explosion are determined. Subsequent simulation results present that the blast wall made of high energy absorbing high manganese steel performs much better in the shock absorption. In this paper, the existing finite element shock analysis using the LS-DYNA program is further extended to study the blast wave response of the corrugated blast wall made of the high manganese steel considering strain rate effects. The numerical results for various parameters are verified by comparing different material models with dynamic effects occurred in the blast wall from the explosive simulation.

In the present study, numerical analysis algorithm for the hull form optimization was taken into account using optimization algorithm. In this algorithm the sequential quadratic programming method was applied as an optimizer and the potential-based panel method was adopted to get the wave resistance coefficient as the objective function. The hull form was modified using the B-spline surface modeling technique during the whole optimization process. The developed numerical analysis algorithm was applied to the 300K VLCC and the optimized ship were compared with the original ship.

In this paper a study on prediction of the wave resistance performance of a very large crude oil carrier(300K VLCC) was taken into account according to the changes in L/B/T. The wave resistance of the ship was calculated using the potential based panel method in which exact nonlinear free surface boundary conditions and the trim and sinkage were considered. The panel cutting method were implemented to generate the hull surface panel and the free surface panel were generated using the variable free surface method. The numerical analysis was carried out according to the 12 different ships. The wave resistance coefficients and the wave patterns of the 12 different ships were compared with each other. As a result the wave resistance of a ship was found to be significantly affected in L/B than T.

Salmonellosis is a significant public health concern and a major cause of bacterial foodborne poisoning in Korea. Approximately 95% of salmonellosis cases in humans are related to the intake of contaminated food products, which mostly originate from livestock such as poultry, pigs, and cattle. To successfully develop strategies to reduce the spread of Salmonella, it is important to investigate the prevalence of Salmonella spp. isolated from food animals and meat. In Korea, the prevalence of Salmonella spp. in cattle was 1.2 2.0%, whereas in pigs it was 1.5 21%. Of all livestock and meat products analyzed, the Salmonella isolation rate was the highest in chickens (18.8 30.3%) and their meat. Antibiotic resistance is an important social issue. The frequent use of antibiotics in the livestock industry has led to increased antibiotic resistance in Salmonella isolates that are extracted from livestock, which raises serious public health concerns. To prevent the spread of antibiotic resistance, it is essential to collect data related to antibiotic-resistant Salmonella strains isolated from food animals and meat. Antibiotic resistance tests revealed that Salmonella isolated from cattle, pigs, and poultry were highly resistant to tetracycline and streptomycin. Recent studies show that the overuse of antibiotics in food animals can also affect antibiotic resistance in humans. Therefore, it is important to establish an appropriate management strategy to successfully prevent misuse of antibiotics within the Korean livestock industry.

본 연구는 임파워링 리더십과 혁신행동의 관계에서 다차원 저항의 매개효과를 실증적으로 규명하는 것에 목적이 있다. 연구에 활용된 자료는 서울과 경기도 지역 사기업 종사자를 대상으로 하였으며 분석에는 396명으로부터 응답된 자료가 활용되었다. 연구의 결과는 첫째, 임파워링 리더십은 건설적 저항과 혁신행동에 긍정적인 영향력이 있으며, 역기능적 저항에 부정적인 영향을 미치는 것으로 확인되었다. 둘째, 다차원 저항(건설적 저항, 역기능적 저항)과 혁신행동의 관계에서 건설적 저항만이 혁신행동에 긍정적인 영향을 미치는 것으로 규명되었다. 셋째, 다차원 저항의 매개효과에서는 건설적 저항만이 임파워링 리더십과 혁신행동의 관계를 부분 매개하는 것으로 구명되었다. 연구의 학문적 시사점으로는 첫째, 임파워링 리더십과 다차원 저항유형의 관계를 규명하여 리더십 연구영역에 부하 저항을 활용할 수 있는 근거를 제시하고 있다. 둘째, 임파워링 리더십과 혁신행동의 관계를 규명함으로써 연구결과를 다양한 선제적 행동으로 확대할 수 있는 논리를 제공하고 있다. 셋째, 기존의 단일차원 저항연구를 다차원 저항으로 확대하여 저항의 긍정적 효과제시하고 있으며, 아울러 건설적 저항의 매개 메커니즘을 규명함으로써 이 분야의 연구 확대에 의미있는 정보를 제공해 주고 있다. 실무적 측면에서도 임파워링 리더 육성과 건설적 저항을 흡수할 있는 제도적 장치의 필요성을 제안하고 있다.