본 연구는 계란 생산성, 계란품질 및 악취저감에 관한 Bacillus subtillus, Streptomyces galilaeus 및 Sphingobacteriaceae로 구성된 복합생균제(PM, probiotic mixture)의 효과를 조사하였다. 산란계 Hy-Line Brown 240수를 4처리구로 구분하여 6주 동안 사육하였다. 처리구는 복합생균제를 함유하지 않은 대조구(CON, control), 일반생균제(CP3, commercial probiotics 0.3%), 복합생균제 3(PM3, 복합생균제 0.3%), 복합생균제 5(PM5, 복합생균제 0.5%)로 구분하였다. 산란율, 계란 호우유니트, 난각두께, 난각강도, 난황색 및 농후난백 높이는 PM3, PM5가 CON 및 CP3에 비해서 높았다. 계분으로부터 암모니아, E. coli, 총호기성균, Coliform, Salmonella 균수는 CON>CP3>PM3>PM5 순서로 증가하였다. 본 결과는 B. subtillus, S. galilaeus 및 Sphingobacteriaceae로 구성된 복합생균제 0.3%가 산란율, 계란품질 개선 및 분에서 암모니아 발생을 낮추어 양계장 악취저감 효과를 갖는다는 점을 보여 준다.

PURPOSES : It is well known that low temperature cracking is one of the most serious distresses on asphalt pavement, especially for northern U.S. (including Alaska), Canada and the northern part of south Korea. The risk of thermal cracking can be numerically measured by estimating thermal stress of a given asphalt mixture. This thermal stress can be computed by low temperature creep testing. Currently, in-direct tensile (IDT) mixture creep test mentioned in AASHTO specification is used for measuring low temperature creep properties of a given asphalt mixture. However, IDT requires the use of expensive testing equipment for performing the sophisticated analysis process, however, very few laboratories utilize this equipment. In this paper, a new and simple performance test (SPT) method: bending beam rheometer (BBR) mixture creep testing equipment is introduced, and the estimated experimental results were compared with those of conventional IDT tests. METHODS: Three different asphalt mixtures containing reclaimed asphalt pavement (RAP) and roofing shingles were prepared in the Korea Expressway Corporation (KEC) research laboratory. Using the BBR and IDT, the low temperature creep stiffness data were measured and subsequently computed. Using a simple power-law function, the creep stiffness data were converted into relaxation modulus, and subsequently compared. Finally, thermal stress results were computed from relaxation modulus master curve using Gaussian quadrature approach with condierations of 24 Gauss number. RESULTS: In the case of the conventional asphalt mixture, similar trends were observed when the relaxation modulus and thermal stress results were compared. In the case of RAP and Shingle added mixtures, relatively different computation results were obtained. It can be estimated that different experimental surroundings and specimen sizes affected the results. CONCLUSIONS: It can be said that the BBR mixture creep test can be a more viable approach for measuring low temperature properties of asphalt mixture compared to expensive and complex IDT testing methods. However, more extensive research and analysis are required to further verify the feasibility of the BBR mixture creep test.

At a two phase flow, according to gas and liquid phase flow rates, various flow regimes are developed such as bubbly, slug/plug, churn, annular, droplet flow and so on. At a two phase flow in small scaled channels, among various flow regimes, the intermittent flows such as bubbly, slug/plug flow are developed in the broad regions of two phase flow pattern map. In particular, the flow regimes are influenced by surface wettability. In a case of slug flow in hydrophobic small scaled channels, gas and liquid phases are perfectively separated by interfaces and contact line. The pressure drop of the two-phase flow is largely generated at moving contact line. Therefore, to well design two-phase flow system with small scales, it is important to estimate the pressure drop at moving contact line. In this study, on the basis of previous research, the pressure drop at moving contact line is experimentally measured for a various fluids (0-40% water-ethanol mixtures). And, the previous correlation to estimate pressure drop at moving contact line is verified by experimental data. In an addition, we discuss interfacial broken phenomena of slug flow in a minichannel. (D=1.555mm).

ZnO thin-films are grown on a p-Si(111) substrate by RF sputtering. The effects of growth temperature and O2 mixture ratio on the ZnO films are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and roomtemperature photoluminescence (PL) measurements. All the grown ZnO thin films show a strong preferred orientation along the c-axis, with an intense ultraviolet emission centered at 377 nm. However, when O2 is mixed with the sputtering gas, the half width at half maximum (FWHM) of the XRD peak increases and the deep-level defect-related emission PL band becomes pronounced. In addition, an n-ZnO/p-Si heterojunction diode is fabricated by photolithographic processes and characterized using its current-voltage (I-V) characteristic curve and photoresponsivity. The fabricated n-ZnO/p-Si heterojunction diode exhibits typical rectifying I-V characteristics, with turn-on voltage of about 1.1 V and ideality factor of 1.7. The ratio of current density at ± 3 V of the reverse and forward bias voltage is about 5.8 × 103, which demonstrates the switching performance of the fabricated diode. The photoresponse of the diode under illumination of chopped with 40 Hz white light source shows fast response time and recovery time of 0.5 msec and 0.4 msec, respectively.

본 연구의 목적은 arbutine과 유용성감초추출물 혼합물의 미백 효과를 조사하는 것이다. B16 melanoma 세포에서 알부틴 및 유용성 감초 추출물의 tyrosinase 활성과 멜라닌 생성 억제 효과를 시험관내에서 평가하여 미백 효과를 측정 하였다. B16 흑색 종 세포를 이용한 MTT 분석은 혼합물 (알부틴과 유용성감초추출물)이 세포독성이 없음을 확인하였다. 유용성 감초 추출물과 알부틴은 모두 mushroom tyrosinase 활성이 농도 의존적 효과를 보였다. 혼합물은 다양한 농도 (유용성감초추출물 : 알부틴 = 1 : 1, 1 : 1.5, 1 : 2, 1 : 2.5, 1 : 5)에서 B16 melanoma 세포에서 40-51 %의 tyrosinase 활성을 유의하게 억제하였다. 또한, 시험한 모든 혼합물은 B16 melanoma cell의 멜라닌 함량을 50 % 이상 감소시켰다. 이러한 결과는 알부틴과 유용성감초추출물 혼합사용 시 미백 활성에 효과적임을 시사하는 바이다.

본 연구의 목적은 온탕침지와 pH교정석회유황합제 처리에 의한 상추 유기종자의 곰팡이와 세균의 소독효과 및 발아율에 미치는 영향을 검정하고자 하였다. 상추종자에 Alternaria sp.가 53.3% 감염되어 있었고 Aspergillus sp.와 Cladosporium sp.은 각각 14.5%와 5.4% 감염되어 있었다. 세균은 형태적으로 Pseudomonas sp., 한 종만 분리되었으며 16.5%가 감염되어 있었다. 상추종자 소독에 효과적인 온탕침지조건을 탐색하고자 온탕의 온도조건(45℃, 50℃, 55℃, 60℃)에 따른 소독효과를 조사하였다. 온탕침지 온도와 처리시간이 증가함에 따라 곰팡이와 세균에 대한 살균효과는 증가하였으나 종자의 발아율은 급격히 감소하였다. 온탕침지 단독처리는 50℃ 온탕에서 20분간 처리할 경우 상추종자의 살균효과와 발아율이 각각 91.1%로 가장 우수하였다. 상추종자 소독을 위한 온탕침지와 pH교정석회유황합제 교호처리는 50℃의 온탕침지 조건에서는 10분간 처리하는 것이 상추종자의 살균효과와 발아율이 각각 100%와 97.6%로 가장 높았다. 본 연구결과는 종자 표면뿐만 아니라 종자내의 곰팡이나 세균을 살균할 수 있는 기술개발에 기여할 수 있을 것으로 생각한다.

PURPOSES : The use of reclaimed aggregate has been recently increasing with the increase in the amount of waste asphalt concrete. The application of these materials can reduce the properties of the asphalt pavement when compared with the case when recycled aggregate is not used. The objective of this study is to evaluate the performance of the asphalt mixtures with various mix ratios of reclaimed aggregate. METHODS : To measure the performance, the following tests using the mixtures prepared in accordance with the Korea Standards were conducted: Hamburg wheel-tracking test, third-scale model mobile loading simulator test, and dynamic modulus test. RESULTS : The test results of the Hamburg wheel-tracking test indicate that the water resistance was similar in each mixture and the plastic deformation resistance was good in the high-ratio reclaimed aggregate mixture. In the case of the third-scale model mobile loading simulator test, the plastic deformation demonstrated a high resistance in the high-ratio reclaimed aggregate mixture. The results were similar to those of the Hamburg wheel-tracking test; however, the cracking resistance was poor with a high recycled aggregate incorporation ratio. The dynamic modulus test results demonstrated excellent resistance to plastic deformation at a relatively high ratio of reclaimed aggregate admixture. The crack resistance was weakened when a high ratio of reclaimed aggregate mixture was used. CONCLUSIONS: As the reclaimed aggregate content increased, the plastic deformation resistance increased and the crack resistance decreased.

PURPOSES : In Korea, asphalt overlay has been used as a typical alternative rehabilitation method for deteriorated pavements. However, asphalt overlay has problems due to poor bonding of the asphalt overlay and the old concrete. Recently, concrete overlays, which have advantages such as long-term durability and high structural capacity to carry heavy traffic, have been considered for rehabilitation construction. However, concrete overlays have limitations such as difficulty in opening to traffic and pavement noise. Recently, an appropriate fine-size exposed aggregate concrete pavement technique was reported to solve these problems. Therefore, this study aims to suggest an optimum mixture design of fine-size exposed aggregate concrete overlay (EACO) that can ensure low noise and early strength. METHODS : The optimum mixture design of fine-size EACO is determined to ensure adequate structural performance for early traffic opening and good functional performances such as low noise. Therefore, the optimum mixture proportion is determined based on the optimum design of aggregate content to produce a low-noise pavement texture by controlling the exposed aggregate number (EAN) and mean texture depth (MTD). RESULTS : The water-cement ratio and unit cement ratio were used to determine the mixture designs to achieve workability and adequate strength for early traffic opening. The texture was determined by selecting the maximum size of coarse aggregate smaller than 10 mm with an S/a ratio of less than 30% for low noise. With these mixture proportions, the EAN and MTD were 50±5 / 25cm2 and 1.0±0.2 mm. Respectively, which meet the criteria for EACO. CONCLUSIONS: In this study, an optimum mixture design of EACO for early traffic opening and low noise is suggested by using earlyhigh strength cement, and the pavement texture is implemented considering EAN and MTD. In addition, a pavement surface texture criterion is suggested for the quality control of EACO.

소나무재선충병의 예방을 위하여 실시하는 예방나무주사는 소나무재선충 피해를 예방할 수 있는 매우 효과적인 방제방법이지만 매개충에 대해서는 효과가 밝혀진 바 없다. 본 연구는 살선충제와 살충제가 혼합된 약제를 소나무재선 충병 방제를 위해 나무주사를 실시하면 매개충에 대한 구제와 소나무재선충에 대한 예방효과가 동시에 가능한 방제방법을 개발하기 위하여 실시하였다. Abamectin+Sulfoxaflor DC을 비롯한 3개 약종을 각 2,000배로 희석한 후 솔수염하늘소에 2㎕를 경구투여하여 소화중독에 의한 살충효과를 평가하였다. 살충제 경구 투여 후 신경흥분에 의한 경련반응을 조사한 조사한 결과 Emamectin benzoate+Acetamiprid DC의 경우 경련비율이 가장 높게 나타났으며, 반수치사시간(LT50)도 암컷은 122.18시간, 수컷은 139.55시간으로 나타나 소화중독 효과가 우수한 것으로 나타났다. 따라서 합제를 이용하여 소나무재선충병 매개충 방제와 소나무재선충의 예방효과를 위한 나무주사시에는 Emamectin benzoate+Acetamiprid DC가 매개충에 대한 살충효과가 가장 우수한 것으로 나타났다.

목적: 항균제 polyhexamethylene Biguanide(PHMB), epigallocatechin gallate(EGCG) 및 PHMB/EGCG 혼합물의 각막상피세포(primary human corneal epithelial cells, HCEpiCs)에 대한 급성독성을 평가하고자 하였다. 방법: 각막상피세포를 0.00001~0.005% PHMB, 0.001~5% EGCG 및 0.00005% PHMB/0.05% EGCG 혼합물이 각각 포함된 배양액에서 30분, 60분, 120분 및 240분 동안 배양하였다. 배양한 각막상피세포를 고정한 다음 Draq 5로 염색하고 공초점현미경과 ImageXpress UltraTM를 이용하여 세포형태를 관찰하여 세포 생존율과 세포자살(apoptosis)을 비교하였다. 결과: 배양된 각막상피세포는 0.00005% 이하의 PHMB 농도 및 0.05% 이하의 EGCG 농도에서는 세포 독성이 나타나지 않았다. 0.00005% PHMB/0.05% EGCG 혼합물이 포함된 배양액에서 급성 세포독성은 관찰되지 않았으나 240분 배양시킨 경우에는 손상된 각막상피세포 수가 증가하고 생존 세포의 수는 감소하였다. 결론: 항균 시너지 효과를 갖는다고 보고된 0.00005% PHMB/0.05% EGCG 혼합물의 경우 각막상피세포에 대한 급성독성은 없었으나 만성효과에 대해서는 추가적인 연구가 필요할 것으로 생각된다.

PURPOSES: Using recyclable materials in asphalt pavement industry is one of the essential tasks not only for saving construction budgets but also for mitigating environmental pollutions. Over the past decades, several efforts have been made by road maintenance agencies to incorporate various recyclable materials into virgin asphalt paving mixtures. As a result, reclaimed asphalt pavement (RAP), which consists of old pavement material was selected as one of most widely used recyclable materials. In this paper, the effects of using different amounts of single-recycled RAP (SRRAP) and double-recycled RAP (DRRAP) on the low-temperature characteristics of asphalt mixtures were investigated. METHODS: To evaluate the low-temperature characteristics of SRRAP and DRRAP mixtures, two experiments, the bending beam mixture creep test and semicircular bending fracture test were performed. The experimental parameters: creep stiffness, m-value, thermal stress, critical cracking temperature, fracture energy, and fracture toughness were computed then compared. RESULTS : RAP mixtures (SRRAP or DRRAP) showed lower mechanical performance compared with conventional asphalt mixtures. The differences became distinct with increased RAP addition. However, the performance differences between SRRAP and DRRAP mixtures were not significant in all cases, which indicate the possible application of re-recycling technology (DRRAP) in the asphalt pavement industry. CONCLUSIONS : The addition of RAP to virgin asphalt can mitigate low-temperature performance despite the improvement in fracture performance observed in some cases. Therefore, using RAP (SRRAP or DRRAP) mixtures on inter or sublayer construction, but not on the surface layer, is recommended. Moreover, the possibility of applying double-recycling technology in asphalt pavement industry can be introduced in this study because not significant performance differences were found between SRRAP and DRRAP mixtures especially at low temperature.

PURPOSES: The object of this study is to select appropriate inorganic materials, and find the best mixing formula to secure fast curing time and enough initial strength, and then to evaluate the durability of the asphalt mixtures according to the degree of addition of the compound manufactured by the determined blending ratio. METHODS : The breaking time and reactivity between seven kinds of inorganic minerals, and the selected recycled aggregate and emulsified asphalt were compared to determine the best initial curing strength for the mixtures. Then, three inorganic materials were chosen as the materials that provide good breaking time and reactivity, and the best mixing formula for the three materials was determined. The chemical composition of the compound manufactured using the mixing formula was analyzed by energy dispersive x-ray system method. Finally, indirect tensile strength (ITS) test was performed (for two days) at room temperature to determine the proper amount of additives that will provide the best initial strength. RESULTS: From the results of the reactivity test, the best mixing formula (A:C:G = 60:30:10) for the three selected inorganic materials with short braking time and high reactivity was determined. The four types of cold reclaimed asphalt mixtures for ITS testing were manufactured by adding the inorganic material compounds at 0%, 3%, 5%, and 7%, and the ITS values were measured after two curing days. The ITS values at 5% and 7% were 0.308 MPa and 0.415 MPa, respectively. The results of quality control tests (Marshall stability, porosity, flow value, etc.) at 5% and 7% satisfied the specification criterion for the cold recycled asphalt mixtures. CONCLUSIONS : The selected inorganic materials (A, C, and G) and the best mixing formula (A:C:G = 60:30:10) accelerated the reaction with emulsified asphalt and shortened the curing time. Depending on the inorganic material used, the breaking time and reactivity can be directly related or unrelated. This is because of the chemical compositions of recycled aggregates, infiltrated foreign matter, and chemical reactions between the inorganic materials and other materials. Therefore, it is important to select the proper materials and the best mixing formula when evaluating the characteristics of the practically used materials such as recycled aggregates, inorganic materials, and emulsified asphalt.

PURPOSES : The purpose of this study is to examine the manufacturing method for emulsified asphalt and its bond performance by analyzing the properties of the emulsifier used to produce cold recycled asphalt mixtures. METHODS: In this study, four types of slow-setting cationic emulsifiers, a microsurfacing emulsifier, and six types of nonionic emulsifiers were used to manufacture emulsified asphalt. Because each emulsifier requires its own unique effective dose to provide the best performance, the optimum asphalt content for each effective dose was determined. Then, the optimum asphalt content for the emulsified asphalt mixture was determined by the tests to check its basic physical properties. By using the determined optimum content, asphalt mixtures were manufactured and dynamic immersion and tensile strength tests were conducted on the mixtures to analyze the influence of the emulsifier on the physical properties of the mixtures. RESULTS : The dynamic immersion test results showed a coating ratio of 54-85%, which is considerably higher than that of using ordinary straight asphalt. The tensile strength test yielded noncompliant values less than 0.4 N/mm, which is the standard requirement for dry indirect tensile strength. The correlation analysis between the dynamic immersion and tensile strength ratio tests showed very high correlation of 0.78. The correlation between the emulsifier content and water resistance performance was low, between -0.55 and -0.24. CONCLUSIONS : While the storage stability improves with increasing emulsifier, the effectiveness proportional to the increase is weaker as the emulsifier increases. The performance testing of asphalt residues before and after manufacturing the emulsified asphalt showed no significant change. It is proved that the emulsified asphalt maintains high coating resistance according to the dynamic immersion test results. In addition, according to the results of tensile strength ratio, cold recycled asphalt mixtures manufactured by the materials normally and commercially used are not compliant with the national standard specification; thus, additional effective materials will be needed for quality compliance. In conclusion, it is evident that the dynamic immersion and tensile strength ratio tests have good correlation, but the quantity of emulsifiers used is not related to the level of moisture resistance.

The effect of water vapor addition on the ignition delay of iso-octane/air mixture was numerically investigated with detailed chemical reaction mechanism. The Chemkin-III was utilized to evaluate the delay time of autoignition for isobaric conditions. By dilution effect and thermal effect, water vapor addition increases the ignition delay time. However, the chemical effect by adding water vapor makes the ignition delay shortened. The ignition delay by the chemical effect is reduced by two ways. Dissociation of water vapor increases the quantities of OH and H. One way is that OH directly makes the rate of iso-octane oxidation reaction 2 increase. The other is that HO2 is produced more by three-body reaction, H+O2+M →HO 2+M, which makes the rate of iso-octane oxidation reaction 3 increase. All trends of three effects are similar according to water vapor addition.