PURPOSES: The objective of this study is to evaluate the physical properties of recycled asphalt mixtures reinforced with glass fiber. METHODS: Firstly, mixing design was conducted on recycled asphalt mixture for use of 50% recycled aggregate. Various laboratory tests were performed on four types of recycled asphalt mixtures with different glass fiber content to evaluate the physical properties. The laboratory tests include indirect tensile strength test, dynamic modulus test, Hamburg wheel tracking test and tensile-strength ratio to evaluate cracks, rutting and moisture resistance of mixtures. RESULTS: The indirect tensile strength of fiber reinforced glass increased about 139.4%. As a result of comparing the master curves obtained by the dynamic modulus test, the elasticity was low in the low temperature region and high in the high temperature region when the glass fiber was reinforced. The glass fiber contents of PEGS 0.3%, Micro PPGF 0.1% and Macro PPGF 0.3% showed the highest moisture resistance and rutting resistance. CONCLUSIONS : The test results show that use of glass fiber reinforcement can increase the resistance to cracking, rutting, and moisture damage of asphalt mixtures. It is also necessary to validate the long-term performance of recycled asphalt mixtures with glass fiber using full scale pavement testing and field trial construction.

코팅, 발수 및 접착특성이 우수한 불소함유 아크릴계 공중합체를 설계, 제조하였다. 공중합체용 모노머로 methyl methacrylate(MMA), 2,2,2-trifluoroethyl acrylate(FMA) 그리고 2-hydroxyethyl methacrylate(HEMA)를 사용하여 괴상 중합 및 유화 중합으로 반응하여 > 95 %이상 고수율로 공중합체를 제조하였다. 1H-NMR로 화학구조를 확인하였고 DSC와 DMA로 물성분석을 한 결과, FMA의 함량이 5 %에서 10 %로 증가함에 따라 유리전이온도는 3 ℃ 감소하였으며 HEMA의 경우에는 감소폭이 2 ~ 8 ℃로 나타났다. Instron 및 TGA를 이용한 분석에서는 FMA 혹은 HEMA 함량이 10 % 증가함에 따라 괴상 및 유화 중합체 모두에서 인장강도는 29 MPa에서 22 MPa로 감소하였고 Td는 200 ℃에서 180 ℃로 감소하는 경향을 나타내었다. 접촉각은 친수성인 HEMA의 함량이 증가함에 따라 상대적으로 감소하였다.

In 1924, natural roack asphalt, which is called Asbuton, was found in South East Sulawesi, Buton Island, Indonesia. Since 2006, Asbuton has been widely applied on national road, provincial road and district roads not only for low volume traffic roads but also for the medium and heavy traffic roads. The use of Asbuton in Indonesian road infrastructure development is increasing because the deposits are estimated to be 677 million tons while current annual production is only approximately 20,000 tons. Asbuton mainly consist of asphalt and mineral like a Trinidad Lake Asphalt. The asphalt content of Asbuton is about 35% or less. Many researchers agreed that pure asphalt binder should be separated from its minerals of Asbuton in order for the conventional asphalt binder to be used widely and economically. Asbuton could replace the conventional asphalt binder. In this study, fundamental and reheological properties of pure asphalt binder extrcted from Asbuton are evauluated to find a possiblity to repalce it as the conventional asphalt binder. The first, pure asphalt binder extrcted from Asbuton through extraction process. Second, penetration test, softening point test, ductility test, and flash point test are conducted to measure physical properties of pure asphalt binder extrcted from Asbuton. Third, dynami shear rheometer (DSR) test, rolling thin film ovens(RTFO) test, pressure aging vessel(PAV) test, and bending beam rheometer(BBR) test are conducted to determine perfoemance grade as a reheological properties. Based on the limited laboratory test results, pure asphalt binder extrcted from would be possibly used as modified additive to improve physical properties and the performance grade at high tempertaure.

Since 2011, a total length of national highway in Korea is 13,797km and 97.6% of total length of national highway system is paved. Particularly, most of national highway has been paved as asphalt concrete pavement. Currently, many maintenance techniques, such as overlay and surface treatments, are applied on existing pavements depending on the failure levels of pavements. One of maintenance techniques is a hot in-place recycling (HIR) that shows features of cost effective and better performance because of the use of 100% recycling of reclaimed asphalt of existing pavement. HIR is widely used in Europe countries and the U.S. It is recommended to rehabilitate the old and distressed asphalt pavement because it is suitable from the environmental perspective and convenient to use when a road is paved. Since 2002, HIR as a maintenance method has been used to rehabilitate the distressed asphalt pavement in National highway in Korea. Recently, a new HIR system, which consists of three pre-heaters, two recycler and one paver, is introduced in maintenance project in National highway. In this paper, HIR mixtures collected from a new HIR system in the field are tested to evaluate their performance in the laboratory test. First, the reclaimed asphalt (RAP) materials and HIR mixtures are collected in the field project site. Second, the quality evaluation of RAP materials, HIR mixtures and rejuvenator are conducted in the laboratory. Test results of RAP materials and HIR mixtures are satisfied with national specification. Rejuvenator used in the project site is classified as RA-5. Based on the limited teste results, it would be concluded that a new HIR system could be produced a satisfied HIR mixtures in the maintenance projects of National highway.

The objective of this study was to determine the effects of moisture content and screw speed on the physical properties of high moisture meat analogue. Extrusion conditions were moisture content (65, 70%), screw speed (150, 200 rpm), a fixed barrel temperature (160℃), and feeder rate (100 g/min). Specific mechanical energy (SME) input decreased as moisture content increased from 65 to 70%. The high moisture meat analogue at 65% moisture content and 150 rpm had higher water absorption capacity, elasticity, cohesiveness, chewiness and cutting strength than those of high moisture meat analogue at 70% moisture content and 150 rpm. However, the high moisture meat analogue at 70% moisture content and screw speed 200 rpm had a lower integrity index, elasticity, cohesiveness, chewiness and cutting strength than those of high moisture meat analogue at 65% moisture content and 200 rpm. In conclusion, the tested physical properties of high moisture meat analogue were more affected by moisture content than screw speed.

It is a well known that concrete is strong for compression and weak for tension. For reinforcing the weakness and improving the performance about concrete, various methods are used. Fiber reinforced concrete that is one of them has been investigated in this study. The function of fiber in concrete is to improve the stress strain relation and toughness, crack control. It’s applied from normal strength concrete to ultra-high performance concrete. But it is essential to disperse fiber uniformly and to prevent aggregation of fiber in concrete, in order that fiber reinforced concrete show the sufficient performance. The various properties of fiber affect the essential properties, for instance, length and diameter of fiber, source, etc. So, this study evaluated the ultra-high performance concrete with mixed in composite fiber.

고등 복합재료 구조물 제작에 적용되는 고온경화용 에폭시 수지 시스템 경화물의 물리적 특성을 연구하였다. 고온경화용 에폭시 수지 경화물의 표면 몰폴로지는 저온경화용 수지 시편의 표면과는 달리 균일한 몰폴로지를 보여주었다. 이 수지 경화물의 열중량분석 결과 300 oC까지는 무게감소가 거의 없는, 즉 열적으로 매우 안정한 것으로 나타났는데, 이는 높은 가교화밀도에 기인한 것이다. 300-500 oC 영역에 서 급격한 무게감도는 매트릭스 수지의 본격적인 열분해에 기인한 것이다. 시편의 인장 및 압축 특성, 열 변형온도, 밀도, 부피수축 등의 특성을 측정하고 평가하였다.

Polyurethane 중합에 있어서 isocyanate 경화제인 H12MDI와 IPDI의 혼합비율에 따른 물성변화를 조사하여, H12MDI 를 사용한 polyurethane resin은 단단하여 가공성 시험에서 밴딩 시 crack 발생이 심하게 일어났으며 IPDI는 비대칭적인 구조로 인하여 polyurethane resin의 구조가 얽혀 유연성을 가지므로 crack이 발생하지 않은 것으로 보인다. IPDI의 가교 도가 높아 혼합비율이 증가할수록 가공성, 내마모성, 내용제성에서도 향상됨을 알 수 있었다. 반면에, H12MDI의 혼합비 율이 높은 polyurethane resin은 코팅피막이 단단하여 내오염성에서는 우수한 결과를 얻었지만, 오히려 내용제성, 내마모성에서는 취약함을 나타냈으며 적외선 분광 스펙트럼 분석 결과와 실제 점도 경시변화를 관찰한 결과 H12MDI의 혼합비율이 증가할수록 보관 안정성은 높았으며, IPDI의 혼합비율이 높을수록 보관 안정성은 낮았다.

We present a new method for solving an inverse problem of flux emergence which transports subsurface magnetic flux from an inaccessible interior to the surface where magnetic structures may be observed to form, such as solar active regions. To make a quantitative evaluation of magnetic structures having various characteristics, we derive physical properties of subsurface magnetic field that characterize those structures formed through flux emergence. The derivation is performed by inversion from an evolutionary relation between two observables obtained at the surface, emerged magnetic flux and injected magnetic helicity, the former of which provides scale information while the latter represents the configuration of magnetic field.

난대림에서 생육하고 있는 상록활엽수를 자원화하기 위해서 참식나무의 조직적, 물리적, 역학적 특성 을 분석하였다. 조직적 특성은 방사조직의 크기, 너비, 수와 도관의 크기를 관찰하였다. 참식나무의 전 수축률은 접선방향 11.00%, 방사방향 4.64%를 나타내었고 기건수축률은 접선방향 8.00%, 방사방향 2.88%를 나타내었다. 평균연륜폭은 2.93mm, 기건밀도는 0.52g/cm3, 기본밀도는 0.39g/cm3이었다. 휨 강도는 76.97Mpa, 압축강도는 10.97Mpa, 전단강도는 10.13Mpa이었다. 참식나무의 평균연륜폭과 강도 와의 관계는 1% 수준에서 유의성이 인정되는 부의 상관관계가 나타났다. 참식나무는 평균연륜폭의 높은 증가에 반해 강도 감소율은 비교적 낮은 감소를 나타내어 생장률 증가에 따른 강도 감소가 낮아 대경재 의 이용이 경제적이라고 판단된다. 남부지역의 참식나무는 온대에서 난대로 기후가 변화하는 난대 지역 의 산림자원으로 본 목재재질특성 분석결과 유용한 산림자원으로 활용할 수 있을 것으로 생각된다.

SiAlON-based ceramics are some of the most typical oxynitride ceramic materials, which can be used as cutting tools for heat-resistant super-alloys (HRSA). SiAlON can be fabricated by using gas-pressure reactive sintering from the raw materials, nitrides and oxides such as Si3N4, AlN, Al2O3, and Yb2O3. In this study, we fabricate Ybm/3Si12-(m+n)Alm+nOnN16-n (m=0.3, n=1.9, 2.3, 2.7) ceramics by using gas-pressure sintering at different sintering temperatures. Then, the densification behavior, phase formation, microstructure, and hardness of the sintered specimens are characterized. We obtain a fully densified specimen with β- SiAlON after gas-pressure sintering at 1820℃ for 90 min. under 10 atm N2 pressure. These SiAlON ceramic materials exhibited hardness values of ~92.9 HRA. The potential of these SiAlON ceramics for cutting tool application is also discussed.

The relationship of in vitro starch digestibility and gel strength was investigated at various concentrations (10-30%) of rice cultivars with different amylose contents (27.9, 17.9, and 5.2%). As the rice flour concentration increased, predicted glycemic index decreased, but gel strength increased regardless of amylose contents. Gel strength correlated strongly with amylose content, whereas in vitro starch digestibility was more highly affected by rice flour concentration than by amylose contents. Moreover, the impact of degree of gelatinization on in vitro starch digestibility of high amylose rice was also examined in terms of structural features and rheological properties. The digestion rate of fully gelatinized flour was 1.7 times higher than that of native flour, while the disrupted structure with a different gelatinization degree during starch digestion was visually demonstrated through the X-ray diffraction and molecular distribution analysis. The rice flour changed from an A-type to a V-type pattern and showed difference in crystalline melting. The low molecular weight distribution increased with increasing degree of gelatinization during starch digestion. The apparent viscosity also increased with degree of gelatinization. These results demonstrated that the starch digestibility of rice was more affected by concentration than by amylose content, as well as by the degree of gelatinization due to structural difference.

The objective of this study was to determine the effect of moisture content(45, 50, 55%), barrel temperature(140, 150°C), screw speed(150, 250 rpm) and two die configurations on the physical properties of extruded soy protein isolate(SPI). Water holding capacity(WHC), texture, integrity index and nitrogen solubility index(NSI) of extruded SPI were analyzed. The texture of extruded SPI was affected by the die configuration. The physical properties of extruded SPI was significantly influenced by barrel temperature, moisture content and die configuration. The increase in water injection rate and barrel temperature led to increase WHC and NSI. The higher water injection rate led to increase integrity index and texture(elasticity, cohesiveness, chewiness, cutting strength). The extruded SPI at 8 cm die configuration had higher integrity index than those of the 5 cm die configuration. Integrity index and NSI were negatively correlated. Thus, the die configuration can be useful to control quality of extruded SPI.

Purpose: The purpose of this study was to investigate the effect of Carboxylated SWNT (Carbon nanotube, single-walled) on the physical properties of contact lenses. Methods: One of the samples that were used in the experiment contained HEMA, MMA, NVP, and EGDMA as the basic combination, and was referred to as the reference sample. The samples consisting of 0.09% carboxylated SWNT added to the reference sample were referred to as the Ref.Cn samples. The physical characteristics of contact lens were evaluated by measuring water content, refractive index and tensile strength. Results: The water content of the prepared contact lens was measured as 38.54 ~ 39.94%, and the refractive index was measured as 1.4328 ~ 1.4330. The tensile strength of contact lenses with carboxylated SWNT were measured at 0.3177 to 0.3333 kfg. Conclusions: Carboxylated SWNT showed no significant change in water content and refractive index but showed a significant increase in tensile strength.

목 적 : 본 연구는 석시닐-키토산(succinyl-chitosan)을 합성하고 p(HEMA) 하이드로겔과의 상호 침투 고분자 구조 결합을 통해 제조한 콘택트렌즈의 물리적 성질 및 단백질 흡착특성에 대하여 알아보고자 한다. 방 법 : 키토산과 succinic anhydride를 교반하여 석시닐-키토산을 합성 한 다음 HEMA, EGDMA, NVP, AIBN을 공중합하여 건조시킨 콘택트렌즈와 상호침투가교방법으로 콘택트렌즈를 제조하였다. 제조된 콘택트 렌즈의 물리적 특성을 평가하기 위해 함수율, 접촉각, 광투과율, 표면의 거칠기를 측정하였으며, 인공눈물을 제조 한 다음 로리 단백질 정량법을 이용하여 단백질의 흡착특성을 평가하였다. 결 과 : 석시닐-키토산이 가교 되어 있는 콘택트렌즈의 경우 석시닐-키토산이 가교되어 있지 않은 대조 군에 비해 단백질 흡착량의 감소를 나타냈으며, 가교한 석시닐-키토산의 분자량이 클수록 단백질 흡착량이 감소하는 것을 알 수 있었다. 또한 석시닐-키토산의 분자량이 클수록 함수율은 증가하고 접촉각은 감소하여 습윤성의 증가를 확인할 수 있었다. 결 론 : 석시닐-키토산을 p(HEMA) 하이드로겔과 상호 침투 가교 하는 방법을 통해 기존의 콘택트렌즈가 가지는 물성을 해치지 않으면서 습윤성이 뛰어나고 단백질의 흡착을 줄일 수 있는 콘택트렌즈 제조가 가능 할 것으로 사료된다.

Surface morphology and optical properties such as transmittance and haze effect of glass etched by physical and chemical etching processes were investigated. The physical etching process was carried out by pen type sandblasting process with 15~20 μm dia. of Al2O3 media; the chemical etching process was conducted using HF-based mixed etchant. Sandblasting was performed in terms of variables such as the distance of 8 cm between the gun nozzle and the glass substrate, the fixed air pressure of 0.5bar, and the constant speed control of the specimen stage. The chemical etching process was conducted with mixed etching solution prepared by combination of BHF (Buffered Hydrofluoric Acid), HCl, and distilled water. The morphology of the glass surface after sandblasting process displayed sharp collision vestiges with nonuniform shapes that could initiate fractures. The haze values of the sandblasted glass were quantitatively acceptable. However, based on visual observation, the desirable Anti-Glare effect was not achieved. On the other hand, irregularly shaped and sharp vestiges transformed into enlarged and smooth micro-spherical craters with the subsequent chemical etching process. The curvature of the spherical crater increased distinctly by 60 minutes and decreased gradually with increasing etching time. Further, the spherical craters with reduced curvature were uniformly distributed over the etched glass surface. The haze value increased sharply up to 55 % and the transmittance decreased by 90 % at 60 minutes of etching time. The ideal haze value range of 3~7 % and transmittance value range of above 90 % were achieved in the period of 240 to 720 minutes of etching time for the selected concentration of the chemical etchant.

Recycled cenosphere, which is a hollow shaped particle from fly ash, has become attractive as a building material due to its light weight and excellent heat insulation and soundproof properties. In this paper, we investigated the effect of cenosphere size on the physical and optical properties. High brightness of cenosphere as raw material is required for a wide range of ceramics applications, particularly in fields of building materials and industrial ceramic tiles. Cenospheres were sorted by particle size; the microstructure was analyzed according to the cenosphere size distribution. Cenospheres were generally composed of quartz, mullite, and amorphous phase. Colour measurement corresponding to chemical composition revealed that the contents of iron oxide and carbon in the cenospheres were the major factors determining the brightness of the cenospheres.