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        검색결과 81

        21.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The objective of this study is to evaluate the application of soil stabilization method for soft shoulder construction in the iRoad Project of Sri Lanka. METHODS: Firstly, the quantitative analysis of soil strength improvement due to soil stabilization was done for soil samples collected from iRoad construction sites. Two types of soils were selected from iRoad Project sites and prepared for soil stabilization testing by the Road Development Authority. Secondly, the appropriate stabilizer was selected at given soil type based on test results. Two different stabilizers, ST-1 and ST-2, produced in Korea were used for estimating soil strength improvements. Finally, the optimum stabilizer content was determined for improving shoulder performance. The uniaxial compressive strength (UCS) test was conducted to evaluate the strength of stabilized soil samples in accordance with ASTM D 1633. The use of bottom ash as a stabilizer produced from power plant in Sri Lanka was also reviewed in this task. RESULTS: It is found from the UCS testing that a 3% use of soil stabilizer can improve the strength up to 2~5 times in stabilized soft shoulder soils with respect to unstabilized soils. It is also observed from UCS testing that the ST-1 shows high strength improvement in 3% of stabilizer content but the strength improvement rate with increase of stabilizer content is relatively low compared with ST-2. The ST-2 shows a low UCS value at 3% of content but the UCS values increase significantly with increase of stabilizer content. When using the ST-2 as stabilizing agent, the 5% is recommended as minimum content based on UCS testing results. Based on the testing results for bottom ash replacement, the stabilized sample with bottom ash shows the low strength value. CONCLUSIONS: This paper is intended to check the feasibility for use the soil stabilization technique for shoulder construction in Sri Lanka. The use of soil stabilizer enables to improve the durability and strength in soft shoulder materials. When applying the bottom ash as a soil stabilizer, various testings should be conducted to satisfy the specification criteria.
        4,000원
        22.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : We propose a parameter-setting-free harmony-search (PSF-HS) algorithm to determine the individual sound power levels of noise sources in the cases of industrial or road noise environment. METHODS: In terms of using methods, we use PSF-HS algorithm because the optimization parameters cannot be fixed through finding the global minimum. RESULTS: We found that the main advantage of the PSF-HS heuristic algorithm is its ability to find the best global solution of individual sound power levels through a nonlinear complex function, even though the parameters of the original harmony-search (HS) algorithm are not fixed. In an industrial and road environment, high noise exposure is harmful, and can cause nonauditory effects that endanger worker and passenger safety. This study proposes the PSF-HS algorithm for determining the PWL of an individual machine (or vehicle), which is a useful technique for industrial (or road) engineers to identify the dominant noise source in the workplace (or road field testing case). CONCLUSIONS : This study focuses on providing an efficient method to determine sound power levels (PWLs) and the dominant noise source while multiple machines (or vehicles) are operating, for comparison with the results of previous research. This paper can extend the state-of-the-art in a heuristic search algorithm to determine the individual PWLs of machines as well as loud machines (or vehicles), based on the parameter-setting-free harmony-search (PSF-HS) algorithm. This algorithm can be applied into determining the dominant noise sources of several vehicles in the cases of road cross sections and congested housing complex.
        4,000원
        23.
        2018.05 구독 인증기관·개인회원 무료
        Chloride-based deicing material is excellent to dissolve ice and snow in economical but they accelerate deterioration of concrete or corrosion steel reinforced concrete. Chlorine ions contained in the chloride-based deicing material currently used act as catalysts for accelerating corrosion when the air-void level is above a concentration level, even if the airvoid retain the proper alkali level. Environment-friendly CMA based deicing material has been difficult to use due to high unit prices in the past, but recently prices have stabilized. As an environment-friendly deicing material agent citric acid, which is a typical organic acid in citrus fruits, plays a role of controlling pH and preventing oxidation. This is effective against reducing steel corrosion and concrete deterioration. In the long term, environment-friendly deicing material is economical considering the damages of structures due to existing chloride-based deicing material. Although environmnet-friendly deicing material has these various advantages, they are inferior in performance to existing chloride-based deicing material. This study suggests proper utilization methods through analyzing the effects of existing chloride-based and environmentfriendly deicing material. Experimental results show that some environment-friendly products a similar level of ice-melting effects of existing chloride, but the effect of chloride-based deicing material is relatively good. This suggests that the performance of ice-melting is inferior only with the use of the environment-friendly deicing material. Therefore, it is necessary to improve deicing methods using with environment-friendly deicing material such as sand and other friction material. Further, it is considered that if the frozen area is predicted in advance and spraying is possible, the environment-friendly deicing material can be used more effectively.
        24.
        2018.05 구독 인증기관·개인회원 무료
        Subsurface cavities in the asphalt pavement which can cause road depression and cave-in accidents influence on the safety of pedestrians and vehicle drivers in the urban area. The existence of subsurface cavity can increase the tensile strain at the bottom of asphalt layer which is an indicator of fatigue cracking potential, and leads to the weakening of the pavement structural capacity. In this study, the finite element (FE) analysis was conducted to examine the relationship between the critical pavement responses and influencing factors, such as cavity depth and size, asphalt layer thickness, and asphalt concrete modulus. The surface deflections and tensile strains calculated from the ABAQUS FE program were compared to those from ILLIPAVE. It is found from this comparison that there are a good relationship between two analysis results. A three dimensional finite element model which is essential to simulate the hexahedral cavity were used to generate the synthetic database of critical pavement responses. To validate the developed model, the deflection data obtained from field Falling Weight Deflectometer (FWD) testing in four different locations were compared to FE deflections. It is found that the center deflections obtained from the FWD testing and FE analysis are similar to each other with an error values of 2.7, 4.4, 5.5, and 11.9 % respectively. The FE model developed in this study seems to be acceptable in simulating actual field cavity condition. On the basis of the data in the database, various analyses were conducted to estimate the effect of influencing factors on the critical pavement responses. It was found that the tensile strain at the bottom of asphalt layer is affected by all the factors but the most affected by the cavity depth and asphalt concrete modulus. Further studies are recommended to properly account for the effect of cavity’s geometry to pavement response.
        25.
        2018.05 구독 인증기관·개인회원 무료
        ▪ About Heat island? In the city, there are many concrete and asphalt structures easily heated by solar heat. Also, while the fuel of factories, homes and cars in the city is burned, it generates heat at the same time. Due to these, there is the phenomenon called the heat island effect that the temperature of the city is 2 to 5 ℃ as high as of the suburb. As for widely known isolation-heat technology, there are reflection-paint coating(structure and pavement), heat-reduction pavement(water retention). Applying reflection paint to a building and pavement can reduce the surface temperature of the building up to 30 ℃, and 15 ℃ over the pavement. In summer, heat-reduction pavement(water retention) has the effect of reducing the pavement surface temperature to 10~20 ℃ ▪ Solution We can consider ways about applying heat-reduction pavement(water retention) to main section of expressway, spraying water using dirt wagon and applying reflection paint to office and tollgate.
        26.
        2018.05 구독 인증기관·개인회원 무료
        The bond property is mightily important in asphalt construction site as overlay, post-cutting overlay and new establishment of asphalt pavement. If the bonding between the lower and upper pavements isn't approriately applied, the slipping phenomenon can happen due to the tensile stress and shear stress. It can resultantly take the forms of the rutting, failure and other damages. Moreover, the greater damage phenomenon from the intense reflection cracking can be generated when the appropriate methods regarding the cracks or failures on the lower pavement aren't conducted and the bonding with its pavements isn't properly applied. In this regard, the researched content on the existing research is shown below. The types of asphalt emulsion applied to the pavement construction site are classified as Tack-Coat and Prime-Coat in South Korea. The application purpose of Tack-Coat is to bond the pavements comprised of the rigid material. And the application objective of Prime-Coat is to attach the layers consisting the disturbed materials. The best performance related to the optimum application rates depends on the type or property of the emulsified asphalt materials. To solve these phenomenons, the various researches have been globally done. The test methods to obtain the optimum application rates of the asphalt emulsion vary in different organizations or countries. The objective of this research is to develop the tester for Tack-Coat bonding property in accordance with the standards and circumstances of the pavement construction in South Korea. In the nation, the application rate of Tack-Coat is presented as 0.3 l/m2 ~ 0.6 l/m2 in the construction specification and pavement design guideline published in the Ministry of Land, Infrastructure and Transport (MOLIT), but there aren't the specific suggestions. And, it depends on the superintendents or the ordering bodies in the construction sites. In that regard, the objectives of this paper are listed below. First, Suggestion of the test methods regarding the Interlayer Shear Strength in accordance with the domestic construction conditions and standards. Second, Development of the tester for conducting various tests using a tester. Last, Development of the predictive model for the optimum application rates of the emulsified asphalt.
        27.
        2018.05 구독 인증기관·개인회원 무료
        In Sri Lanka, the shoulder in asphalt pavements has been constructed using the materials transported from borrow pit in the iRoad Project due to the low quality of in-situ soils. After excavating 150~200mm thick and 500mm wide shoulder area, the borrow pit materials are placed and compacted according to specifications. The excavated in-situ soils are dumped in designated location. It is estimated that this process of shoulder construction is not economical due to high material transportation cost and can also induce the environmental issues by disposal of in-situ soils. It can also cause distresses such as surface rutting and edge drop-off in soft shoulder section due to bearing capacity failure and off-tracking of vehicle. The heavy rainfall in Sri Lanka can induce severe erosion problem when using the soft shoulder. To improve the strength and durability of pavement shoulders in the iRoad Project, the soil stabilization will be a good alternative to solve the above mentioned problems. The use of in-situ soils with addition of soil stabilizer enables to reduce the construction cost of shoulder section and mitigate the environment issues. The objective of this task is to review the application of soil stabilization method for soft shoulder construction in the iRoad Project. Firstly, the quantitative analysis of soil strength improvement due to soil stabilization was done for soil samples collected from iRoad construction sites. Two types of soils were selected from iRoad Project sites and prepared for soil stabilization testing by the Road Development Authority. Secondly, the appropriate stabilizer was selected at given soil type based on test results. Three different stabilizers, ST-1, ST-2, and ST-3, produced in Korea were used for estimating soil strength improvements. Finally, the optimum stabilizer content was determined for improving shoulder performance. The uniaxial compressive strength (UCS) test was conducted to evaluate the strength of stabilized soil samples in accordance with ASTM D 1633. The use of bottom ash as a stabilizer produced from power plant in Sri Lanka was also reviewed in this task.
        28.
        2018.04 구독 인증기관·개인회원 무료
        The honey bee soluble acetylcholinesterase 1 (AmAChE1) is overexpressed under the overwintering and brood rearing-suppressed conditions. To investigate the role of AmAChE1 in regulating acetylcholine (ACh) titer, ACh concentrations in both the head (central nervous system) and abdomen (peripheral nervous system) were analyzed. ACh titer was significantly lower in both tissues of worker bees under the overwintering and brood rearing-suppressed conditions compared to control bees. Interestingly, the expression levels of choline acetyltransferase (AmChAT) and molecular marker genes of immune systems were significantly reduced in honey bee head under the same conditions. Taken together, ACh titer appears to be reduced via a cooperative interaction of the AmAChE1 overexpression and AmChAT underexpression and to be linked to reduced inmmune responses under the overwintering and brood rearing-suppressed conditions. The roles of AmAChE1 (with little catalytic activity) and AmChAT in the ACh homeostasis and signaling was discussed in the contexts of immune response and longevity regulation in honey bees.
        30.
        2017.10 구독 인증기관·개인회원 무료
        Among two different acetylcholinesterase (AmAChE1 and AmAChE2) of the western honey bee, the soluble AmAChE1might be related with a stress response as judged from its over-expression in honey bee workers when brood rearingwas suppressed. In this study, to ensure the nature of AmAChE1 responding to stress factors, the expression patternsof AmAChE1 were investigated following various treatments, including varroa mite infestation, bacterial challenge, broodrearing suppression, thermal stresses, chemical treatments, ultraviolet B irradiation, starvation, water restriction and crowdingstress. In addition, transcription profiles of four heat shock protein genes known as general stress markers and vitellogeningene, which is induced in several stress conditions, were tested as positive references. In every tested condition, onlybrood rearing suppression and heat shock were related with the expression of AmAChE1.
        31.
        2017.04 구독 인증기관·개인회원 무료
        The frequency and time of the outbreak of insect diseases were investigated among the insect-rearing farms by regional groups. The purpose of this study was to predict the insect diseases and reduce the spread of diseases. From February to October 2016, 87 of diseased insects were collected in seven regions. It turned out that the pathogens for fungal diseases were identified as Metarhizium anisopliae. But in case of bacterial diseases, the pathogenicity of the bacteria isolated from the diseased insects were not confirmed. Bacterial diseases occurred mainly in June and August in Gyeonggi-do and Gangwon-do, while in Chungcheong-do, bacterial and viral disease raged. In Jeolla-do, both fungal and bacterial diseases occurred in June. Generally, bacterial diseases occurred mainly from June to October, while the frugal diseases occurred from January to March. It was concluded that the entomopathogenic fungi, Metarhizium anisopliae, tended to cause diseases during late-winter and early spring and bacteria, uncertain, was prone to cause diseases during summer. Therefore, it necessary to adequately control depending on the type of the entomopathogen.
        32.
        2017.04 구독 인증기관·개인회원 무료
        There are two different types of acetylcholinesterase (AChE1 and AChE2) in the western honeybee as in most of insects. It is suggested that soluble AmAChE1 might be related with a stress response as judged from its elevated expression level in honey bee workers when brood rearing was suppressed. In this study, to ensure the nature of AmAChE1 responding to stress factors, the expression patterns of AmAChE1 following heat shock, brood rearing suppression and chemical treatments (Imidacloprid and fluvalinate) were investigated. Also, several heat shock protein (hsp) genes (hsp10, hsp60, hsp70 and hsp90) known as general stress markers were tested as positive references. Heat shock induced expression of every tested hsp along with AmAChE1. In brood rearing-suppressed worker bees, 7 days old bees showed much higher expression level of AmAChE1 and hsp90 compared to control honey bees. However, treatment of imidacloprid and fluvalinate did not induce any apparent overexpression of these genes. These results confirm that both HSP and AmAChE1 genes generally respond to temperature and brood rearing suppression and further suggest that AmAChE1 can serve as a potential biomarker along with hsps for the detection of stress in honey bee colonies.
        33.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This paper presents a comparison study between dynamic and static analyses of falling weight deflectometer (FWD) testing, which is a test used for evaluating layered material stiffness. METHODS: In this study, a forward model, based on nonlinear subgrade models, was developed via finite element analysis using ABAQUS. The subgrade material coefficients from granular and fine-grained soils were used to represent strong and weak subgrade stiffnesses, respectively. Furthermore, the nonlinearity in the analysis of multi-load FWD deflection measured from intact PCC slab was investigated using the deflection data obtained in this study. This pavement has a 14-inch-thick PCC slab over finegrained soil. RESULTS: From case studies related to the nonlinearity of FWD analysis measured from intact PCC slab, a nonlinear subgrade modelbased comparison study between the static and dynamic analyses of nondestructive FWD tests was shown to be effectively performed; this was achieved by investigating the primary difference in pavement responses between the static and dynamic analyses as based on the nonlinearity of soil model as well as the multi-load FWD deflection. CONCLUSIONS : In conclusion, a comparison between dynamic and static FEM analyses was conducted, as based on the FEM analysis performed on various pavement structures, in order to investigate the significance of the differences in pavement responses between the static and dynamic analyses.
        4,000원
        34.
        2016.04 구독 인증기관·개인회원 무료
        Acetylcholinesterase 1 (AmAChE1) has low catalytic activity and is abundantly expressed in both neuronal and non-neuronal tissues. In previous experiments, we observed that AmAChE1 is rarely expressed in summer while highly expressed in winter. Through additional experiments, the expression of AmAChE1 was suggested to be associated with brood rearing status. Under the assumption that abnormal suppression of brood rearing activity may result in stressful condition in honey bee social community, it was further suggested that AmAChE1 is likely involved in stress management particularly during winter. We hypothesized that the increased docility usually observed in overwintering bees is likely an outcome of stress management in colony, which is mediated by AmAChE1 expression. To verify this, worker bees expressing abundant AmAChE1 were collected in early winter and injected with Amace1 dsRNA to knockdown Amace1. Then, the behavioral activity of the bees was investigated using the EthoVison video tracking system. Honey bees injected with Amace1 dsRNA showed significantly increased motility, which was strongly correlated with the suppressed expression level of AmAChE1 in the abdomen. No apparent reduced expression of AmAChE1 in the head was observed perhaps due to the limited efficacy of RNA interference in the blood-brain-barrier. Our finding suggests that behavioral activity can be regulated, at least, by AmAChE1 expression level in non-neuronal tissue (i.e., fatbody) perhaps via metabolic alteration.
        35.
        2016.04 구독 인증기관·개인회원 무료
        Human body and head lice are obligatory human ectoparasites. Although both body and head lice belong to a single species, Pediculus humanus, only body lice are known to be a vector of several bacterial diseases. The higher vector competence of body lice is assumed to be due to their weaker immune response than that of head lice. To test this hypothesis, immune reactions were compared between body and head lice following infections by two model bacteria, Staphylococcus aureus and Escherichia coli, and a human pathogen, Bartonella quintana. Following dermal or oral challenge, the number of these bacteria increased both in hemocoel and alimentary tract of body lice but not in head lice and the viability of the B. quintana was significantly higher in body louse feces, the major route of infection to human. In addition, body lice showed the lower basal/induced transcription level of major immune genes, cytotoxic reactive oxygen species and phagocytosis activity compared with head lice. These findings suggest that a reduced immune response may be responsible, in part, for the increased proliferation and excretion of viable bacteria which are associated with the high level of human infectivity seen in body versus head lice.
        37.
        2014.10 구독 인증기관·개인회원 무료
        Recently, the expression of acetylcholinesterase1 (AChE1) in honeybee worker has been found to be seasonally fluctuated. Seasonal investigation on the AChE1 expression profiles revealed that it is abundantly expressed in January but its expression was completely abolished in February in both head and abdomen. In an attempt to predict the physiological function of seasonally expressed AChE1, proteomic analysis of honeybee worker was conducted using the samples collected in January and February. Total protein samples separately extracted from the head and abdomen of honeybee forager were compared by 2-D electrophoresis (2-DE). More than 2-fold differences in expression patterns between the two different samples were observed in 50 and 85 protein spots in the head and abdomen, respectively. Among them, 20 protein spots showing >17-fold differences in expression between the two different samples of the head were identified by mass spectrometry. Most of the proteins were identified to be the major royal jelly protein (MRJP) families (e.g., MRJP, MRJP2 and MRJP3), which are known to be expressed in nurse bees during brooding season, and their expression was significantly higher in January than in February. This result was unexpected because brooding usually began in the study site apiary during February and the worker bees used for analysis were assumed to be foragers (old workers). Thus, current findings suggest, though speculative, that the workers collected in January may function as nurses despite their old ages in January or that MRJPs may have other not-yet-characterized functions, which is apart from the conventionally known roles. Finally, possible association of MRJPs with AChE1 was discussed.
        38.
        2014.10 구독 인증기관·개인회원 무료
        An easy and rapid resistance detection protocol for the Western flower thrips Frankliniella occidentalis was established based on the residual contact vial bioassay (RCV), in which insecticide resistance levels can be estimated at 8 h-post treatment of diagnostic doses. The RDA strain was used as a reference susceptible strain, which has been reared under laboratory conditions over 10 years without exposure to any insecticides. Seven insecticides were tested for the determination of diagnostic dose. Among them, five insecticides (chlorfenapyr, acrinathrin, spinosad, emmamectin benzoate and thiamethoxam, ranged as 0.03 ~ 0.42 μg-1cm2) were applicable to the RCV. However, two insecticides (omethoate and imidacloprid) were not able to be used for the RCV because the treated inner surface of glass vials by these insecticides were too viscous, causing non-specific mortality. The RCV detection kit was employed for the estimation of resistance levels for the five insecticides in five local populations. Almost field-collected populations revealed high levels of resistance to the four insecticides (acrinathrin, spinosad, emmamectin benzoate and thiamethoxam) by showing less than 50% mortality. The baseline resistance detection by RCV method will facilitate the selection of proper insecticides for farmers to manage insecticide resistant-populations of F. occidentalis.
        39.
        2014.07 구독 인증기관 무료, 개인회원 유료
        The wine industry is an emerging market in Malaysia. This study focuses on identifying the factors influencing wine consumption among working professionals. 309 out of 350 questionnaires distributed in the Klang Valley, Malaysia were useful. The findings show that three factors (self-expression, health and emotion) are statistically significant in determining wine consumption behaviour among working professionals. Although marketers like to believe that their efforts drive the demand of particular wines, it was concluded that labelling and branding of wine was not correlated with wine consumption behaviour. Practical implications for wine producers and marketers are discussed.
        4,200원
        40.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyacetylene (PA) films with vertically aligned fibril morphology were synthesized in homeotropic nematic liquid crystal (N-LC) solvent by using a magnetic field of 5 Tesla as an external perturbation. Scanning electron microscope (SEM) photographs indicated that the lengths of fibrils from the substrate were 5-35μm, depending on polymerization time. Carbonization was carried out using iodine-doped PA film and a morphology-retaining carbonization method. From the SEM results, we confirmed that the vertical morphology of the PA remains unchanged even after carbonization at 800℃. The weight loss of the films due to carbonization at 800℃ is about 20% of the weight of the film before iodine doping. It is expected that vertically aligned carbon might be a precursor for preparing vertical graphite materials, which materials could be useful for electrochemical energy storage and cell electrodes.
        3,000원
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