• International Journal of Highway Engineering
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• v.12 no.4
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• pp.87-92
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• 2010

This study evaluates the laboratory properties of asphalt binder and mixture modified with R-EPDM(Recycling Ethylene Propylene Dien Monometer), which consists of R-EPDM as a main ingredient that is an industrial by-product made by manufacturing waste EPDM below 50 mesh as an additive. Superpave system was used to determine the PG(Performane Grade) and evaluate the property of R-EPDM modified binder. OACs(Optimum Asphalt Contents) of R-EPDM modified asphalt mixtures were determined by Superpave mix design using gyratory compactor and wheel tracking test and moisture susceptibility test were carried out with R-EPDM modified asphalt mixtures at OACs. The results from these tests, rutting-resistance and freezing and thawing resistance by moisture susceptibility of R-EPDM modified asphalt mixtures were superior to one of general asphalt mixtures(AP-5).

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.6
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• pp.79-88
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• 1998

This study was conducted to measure the moisture content of soil using RF impedance in the range of 1 to 30MHz. Considering the water potential flow in the soils, two types of sensor such as parallel cylinder and perpendicular plate type were fabricated and tested. The capacitance and resistance of sonsors for soil samples having moisture content range of 2 to 27% were measured by Q-meter (HP4342). The higher soil moisture content was and the larger soil bulk density was, the more the capacitance of sensors increased. To eliminate the effect of bulk density on measuring soil moisture content using RF impedance, two kinds of model having the density independent functions such as the ratio of capacitance change to conductance change and weight of water and dry soils respectively were developed and estimated by regression analysis.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.111-120
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• 2009

This paper presents a fundamental findings of the functional and structural performance of the porous asphalt concrete coated with MMA resin. To evaluate the structural performance, cantabro, wheel tracking, moisture sensitivity and indirect tensile fatigue tests are performed. The tests results show that the cantabro loss is reduced three times and fatigue resistance is significantly increased after the specimens are coated with MMA resin. However there are little changes in the rutting and moisture damage resistances before and after the coating. Air voids, permeability and BPT(British Pendulum Test) tests are conducted to study the functional performance. It is observed form the tests that the air voids and permeability are slightly decreased after the coating. However, the changes in the air voids and permeability are negligible. The skid resistance of the coated specimens is lower than reference specimens. However, the skid resistance is maintained beyond the level of the reference specimens when silica sands are chipped on top of the coated surface.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.917-935
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• 2020

In this study, an automated sensor to measure forest fire surface fuel moistures was developed to predict changes in the moisture content and risk of forest fire surface fuel, which was indicators of forest fire occurrence and spread risk. This measurement sensor was a method of automatically calculating the moisture content of forest fire surface fuel by electric resistance. The proxy of forest fire surface fuel used in this sensor is pine (50 cm long, 1.5 cm in diameter), and the relationship between moisture content and electrical resistance, R(R:Electrical resistance)=2E(E:Exponent of 10)+13X(X:Moisture content)-9.705(R²=0.947) was developed. In addition, using this, the software and case of the automated measurement sensor for forest fire surface fuel moisture were designed to produce a prototype, and the suitability (R²=0.824) was confirmed by performing field monitoring verification in the forest. The results of this study would contribute to develop technologies that can predict the occurrence, spread and intensity of forest fires, and are expected to be used as basic data for advanced forest fire risk forecasting technologies.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.43-47
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• 2004

We have been using Moisture Barrier Bags for dry packing of semiconductor packages to prevent moisture from absorbing during shipping. Moisture barrier bag material is required to be waterproof, vapor proof and offer superior ESD (Electro-static discharge) and EMI shielding. Also, the bag should be formed easily to the shape of products for vacuum packing while providing excellent puncture resistance and offer very low gas ＆ moisture permeation. There are some problems like pinholes and punctured bags after sealing and before the surface mount process. This failure may easily result in package pop corn crack during board mounting. The bags should be developed to meet the requirements of excellent electrical and physical properties by means of optimization of their raw material composition and their thickness. This study investigates the performance of moisture barrier bags by characterization of their mechanical endurance, tensile strength and through thermal analysis. By this study, we arrived at a robust material composition (polyester/Aluminate) for better packing.

• The Korean Journal of Ecology
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• v.6 no.3
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• pp.227-235
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• 1983

This research was made over drought resistance and optimum soil moisture needed with Plantago asiatica L. as the material by means of making out the process of its growth under different soil moisture contents. The soil used for the experiment was a mixture of vermiculite and c-layer soil, and the process of growth was compared with each other controlling its soil mositure as: 7%, 15%, 30%, 45%, and 60%. In 7% range of soil moisture which was of low content, the increase of growth was neither significantly indicated nor any permanent seeding done. In view of this phenomenon, Plantago asiatica L. appeared to be highly drought-resistant. It was found rising at 30% range and reaching the optimum state at 45% range and falling down at 60% range range. In viw of this fluctuation indicated above, the optimum soil moisture content needed for the growth of Plantago asiatica L. is thought to be between 30% and 60%. It is thought the number of seed per capsule is not affected by the soil moisture content. It is expected an ecotypic variation by the soil moisture content will bring forth upon Plantago asiatica L.

• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.121-130
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• 2004

This study was carried out to develop a miller to produce white embryo rice with functional nutrients by improving the conventional vertical miller. The effects of rice moisture content and the shaft revolution speed of the miller on germ(embryo) adherence rate, whiteness, broken rice rate, and cracked rice rate were investigated. Also, the effect of the mesh size of emery stones on the germ adherence rate was investigated. The vertical prototype miller was improved with the increasement of about 42% in producing white embryo rice at proper conditions(shaft revolution speed of 900 rpm, emery stones of mesh ＃50, processing capacity of 2.3t/h, zero outlet resistance, rice moisture content of 16.2%). The results were as follows: 1. The germ adherence rate of white rice was significantly influenced by the moisture content of brown rice. The germ adherence rate of white rice decreased rapidly with the increase of the moisture content of brown rice. When brown rice with moisture content of 13.2%, 14.5%, 15.2%, 15.4% was milled by the prototype with emery stones of mesh ＃35 and shaft speed of 900(1,100) rpm, rpm adherence rate of milled rice was 76.2%(70%), 69.2%(66%), 45.9(38%), 13.0(9%), respectively. 2. The whiteness of white rice milled by the prototype with emery stones of mesh ＃35 and shaft speed of 1,100(900)rpm increased from 27(23) to about 40, respectively, as the moisture content of brown rice increased from 13.2% to 17.2%. 3. The rate of broken rice of white rice milled at 900rpm decreased by 0.6∼1.0% compared with that at 1,100rpm when the moisture content of brown rice was less than 15.2%. 4. The germ adherence rate was increased by 10.3% and 11.0%, respectively when brown rice with moisture content of 16.2% and 15.5% was milled by the prototype miller with shaft speed of 900rpm and emery stones of mesh ＃50 instead of mesh ＃35. 5. Considering the germ adherence rate, broken rice rate, and whiteness of milled rice, the proper milling conditions of the prototype miller for producing embryo rice were the moisture content of about 15%, the processing capacity of 2.3t/h and minimum outlet resistance of 0Nㆍm with shaft speed of 900rpm and emery stones of mesh ＃50.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.1
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• pp.53-59
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• 1986

The effects of soil moisture on seasonal changes of photosynthesis, transpiration and stomatal resistance were studied in sorghum (Pioneer 931) and sorghum - sudangrass hybird (Pioneer 988) at Suweon in 1985. Soil moisture was maintained with approximately 100, 80, 60 and 40% of field moisture capacity in large concrete pot (12m length $\times$ 1m width $\times$ 1m depth). 1. Photosynthesis and transpiration showed a sharp seasonal changes and reacted similarly to water stress and environmental factors, and were the highest in the middle of August, and were the lowest in the beginning of October. Sorghum - sudan hybird had better photosynthesis, transpiration and stomatal control than those of sorghum in hot summer season. 2. The rate of photosynthesis of 60 and 80% field moisture capacity was higher than that of 100 and 40% throughout growing season, but the effect of soil moisture on photosynthesis varied seasonally by climate factors. Optimum soil moisture was 60% in early summer and fall, and was 60 - 80% in hot summer season. 3. Drought and over-moisture affected physiological metabolism of plant, and so the dry matter yield of 40 and 100% field moisture capacity decreased by 70% compared with that of 60% field moisture capacity.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.819-826
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• 2017

The effects of thermocycling procedure and material shade on the mechanical properties and wear resistance of resin-based dental restorative materials are investigated. The modulus of elasticity, hardness, plasticity index and wear resistance are determined for the conventional composite, the nanohybrid composite and the nanofilled dental composites. Disc-shape samples are prepared from each material to investigate the effects of thermocycling procedure on the mechanical properties and wear resistance of different types of dental restorative materials. In this respect, a group of samples is thermocycled and the other group is stored in ambient conditions. Then nano-indentation and nano-scratch tests are performed on the samples to measure their mechanical properties and wear resistance. Results show that the A1E shade of the dental nanocomposite possesses higher modulus of elasticity and hardness values compared to the two other shades. According to the experimental results, the mean values for the modulus of elasticity and hardness of the A1E shade of the nanocomposite are 13.71 GPa and 1.08 GPa, respectively. The modulus of elasticity and hardness of the conventional dental composite increase around 30 percent in the oral environment due to the moisture and temperature changes. The wear resistance of the dental composites is also significantly affected by moisture and temperature changes in the oral conditions. It is observed that thermocycling has no significant effect on the hardness, plasticity index and wear resistance of the nanohybrid composite and the nanocomposite dental materials.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.112-119
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• 2015

The pulp mold attract the increasing concern as recyclable, biodegradable, and eco-friendly packaging materials. In order to broaden the applicability of the pulp mold as substitutes of the expanded styrofoam, the properties of various raw materials for the pulp mold were evaluated and the way for improving water resistance properties of the pulp mold were also tested by applying some additives. The higher value in the fines contents and in the water retention value were shown for the TMP (thermomechanical pulp), which resulted in the bulkier pulp mold with the higher moisture absorption property. In case of water resistance properties, the pulp mold made of white ledger stock showed the higher value in water contact angle and very slow water absorption rate. The addition of oil palm EFB fiber showed the improvement in the water resistance of the pulp mold made of UBKP. The effects of various additives on the improvement in the water resistance properties of the pulp mold were tested by using AKD, PVAm, epoxy resin. The application of AKD leaded to the higher increase in the water resistance. The results in this study showed the effects of AKD for the pulp mold could be improved and optimized by the application with fixing agent and by the ageing treatment after production.