PURPOSES : Recently, the generation of industrial by-products has been increased owing to the increase in electrical power consumption. This experimental study investigated a special mortar development using outstanding benefits of porous structures in heavy oil fly ash (HOFA) and bottom ash (BA) to reduce heat transfer and weight of tunnel repair mortar. METHODS : Based on the concept of materials usable for this objective being porous and light, the physical and chemical properties of heavy oil fly ash and bottom ash were analyzed to determine the application possibility for tunnel repair mortar. In addition to satisfying this primary requirement, the research aimed at determining the relationships between the characteristics of porous structures and effectiveness of reducing weight and thermal conductivity. This study was undertaken on the use of bottom ash as fine aggregate and heavy oil ash as filler in mortar mix proportion. Four different levels of bottom ash (25%, 50%, 75%, 100%, and 5%), and 10%, 15%, and 20% of heavy oil fly ash were investigated to determine the proper replacement amount within the designed specification. According to the analytic results on the effectiveness of both by-products and chemical additives, the repair mortar with optimum mixture proportion was investigated using various tests including thermal conductivity and porosity. RESULTS : The use of porous by-products increased the demand for mixing water in obtaining the required flowability, but the compressive strength did not decrease significantly in proportion by adding an amount of bottom ash. Based on the results, bottom ash can be replaced with aggregate as much as 50%, but adding an amount of heavy oil ash is suggested as below 10% in formulation. CONCLUSIONS : The optimized repair mortar, which was produced by conclusive formulation, was evaluated as a high-performance material to repair tunnels with the effectiveness of porous and remarkable physical properties.

Chinese cabbage or pakchoi (Brassica Rapa subsp. Chinensis) is one of the most popular vegetables in Korea. It is grown and consumed throughout the year because it has many benefits. This study reports on the growth performance of pakchoi grown in the hydroponic system using a Food Juke Box (FJB) under different light compositions. The chlorophyll content (CC), root fresh weight (RFW), and shoot fresh weight (SFW) were measured. Further, various vegetation indices (VIs), such as modified chlorophyll absorption in reflectance index (MCARI1), normalized difference vegetation index (NDVI), optimized soil-adjusted vegetation index (OSAVI), and structure insensitive pigment index (SIPI), were employed to predict SFW. The study results indicated a significant increase in the CC of pakchoi with different light treatments compared with the control. The CC was highest under treatment with 70% white light, 20% blue light, and 10% red light (T1) than under treatment with 50% white light, 30% blue light, and 20% red light (T2). All used VIs showed significant differences with different light combination treatments. There was no significant change in RFW and SFW between the control and T1. However, a significant reduction in RFW and SFW was observed in T2 compared with the control. A comparison between T1 and T2 demonstrated that RFW and SFW were increased by 23% and 25%, respectively, compared with those in T2. The correlation result showed that SFW had a significant positive correlation with RFW (0.76***). Further, a significant negative correlation was observed with OSAVI (−0.25*), MCARI1 (−0.54***), and CC (−0.19*). In conclusion, our findings implied that different light combinations in pakchoi affected the photosynthetic pigments although they did not improve SFW. This research will pave the way for pakchoi production in hydroponics using smart farming FJB. This will further promote plant development, especially for domestic consumption, and help fulfill the growing demand for leafy vegetables.

일상적인 화학제품들의 사용량이 증가함에 따라 사용되었던 염료 폐기물 처리 또한 중요한 환경 적인 문제로 대두되었다. 이러한 염료폐기물은 광촉매를 이용하여 분해시킬 수 있는데, 졸-겔 기술을 활용 하면 매우 비용 효율적으로 광촉매를 합성할 수 있다. 졸-겔 기술은 나노스케일의 막 형성에도 상당히 유 용하며 간단하게 다층구조를 형성할 수도 있다. 본 연구에서는 다양한 염료 분해에 효과가 있는 산화아연 (ZnO) 이용하여 다중 회전도포 방법으로 다층구조(3층, 5층)를 가진 ZnO 막을 형성하였다. 성능비교를 위해 단일 회전도포 방법에 의한 단층구조를 가진 ZnO 막을 대조군으로 준비하였다. X선 회절분석기 및 에너지 분산 X선 분광계를 이용하여 ZnO의 구조 및 원소분석을 수행하였고, 주사전자현미경을 통해 나노 선같은 표면형상을 관찰할 수 있었다. 추가적으로 UV-Vis 분광광도계를 활용하여 자외선의 흡수도를 측정 하였다. 5층구조를 가진 ZnO 막이 단층 구조를 가진 ZnO 막에 비해 모의 메틸렌 블루를 49% 더 많이 분해하였다. 결론적으로, 다층구조를 가진 ZnO 는 메틸렌블루 염료를 더욱 효과적으로 분해하는 광촉매로 써 유용하다는 알 수 있었다.

We introduce the Transformable Reflective Telescope (TRT) kit that applies an aluminum profile as a base plate for precise, stable, and lightweight optical system. It has been utilized for optical surface measurements, developing alignment and baffle systems, observing celestial objects, and various educational purposes through Research & Education projects. We upgraded the TRT kit using the aluminum profile and truss and isogrid structures for a high-end optical test device that can be used for prototyping of precision telescopes or satellite optical systems. Thanks to the substantial aluminum profile and lightweight design, mechanical deformation by self-weight is reduced to maximum 67.5 μm, which is an acceptable misalignment error compared to its tolerance limits. From the analysis results of non-linear vibration simulations, we have verified that the kit survives in harsh vibration environments. The primary mirror and secondary mirror modules are precisely aligned within 50 μm positioning error using the high accuracy surface finished aluminum profile and optomechanical parts. The cross laser module helps to align the secondary mirror to fine-tune the optical system. The TRT kit with the precision aluminum mirror guarantees high quality optical performance of 5.53 μm Full Width at Half Maximum (FWHM) at the field center.

In this study, a mixed resin containing Bis-GMA was developed to produce a light-emitting sign using quantum dots. As a result of measuring the viscosity, color coordinates change, and luminance of the mixed resin, the following conclusions were obtained. The viscosity of the mixed resin decreased as the content of the diluent increased, and viscosity values ​​ranged from 3,627 to 1,349cps showed as a result. The viscosity of the mixed resin decreased as the temperature increased, and the viscosity showed a value of 5,156 to 1,132cps. For the optical properties of InP/GaP/ZnSe/ZnS quantum dots, the absolute quantum efficiency was 91% at 522nm and 90% at 618nm when the gallium was 0.01%. The luminance of the light-emitting sign using the resin mixed with quantum dots was showed 142.6cd/m2 in white and 104.2cd/m2 in the red region.

본 연구는 고온과 연속광 조건 하의 복합 스트레스 환경에서 실내 관엽식물이 어떤 엽록소 형광 반응을 나타내는지에 대해 조사 및 분석했다. 대부분의 실내 관엽식물은 이와 같은 스트레스 조건에서 광도가 높아질수록 Fo, Fj 단계에서 형광 밀도가 증가하고 Fi, Fm 단계에서 형광 밀도가 감소한 것으로 나타나 광계II의 반응중심에 있는 전자수용체 퀴논의 상당량이 환원상태에 놓여있음을 암시했다. 뿐만 아니라 최대 양자효율과 최대 양자수율을 나타내는 Fv/Fm와 ΦPo는 광도가 높아질수록 낮게 나타났고 반대로 에너지 소산을 나타내는 DIo/RC 값은 광도가 높아지는 것에 비례하여 높게 나타났다. 이를 미루어보아 고광도 수준에서는 대부분의 광자가 제대로 활용되지 못했음을 알 수 있었다. 특히나 아이비와 테이블야자 는 고온 및 연속광 조건에서 현저한 스트레스를 받는 것으로 분석되었는데 이와 같은 스트레스 조건의 실내에서 재배할 경우 60 μmol m-2 s-1의 저광도 수준에서 재배하는 것이 바람직한 것으로 보인다. 반대로 무늬스킨답서스와 관음죽은 스트레스를 비교적 적게 받는 것으로 나타나 고온과 연속광 조건하에서도 광도의 세기와는 무관하게 양호한 생육이 가능할 것으로 판단된다.

PURPOSES : The purpose of this study is to establish a scientific and rational structure pavement maintenance technique and management standard through field investigation and analysis method development for measuring damage to structure pavement such that fundamental quality improvement can be promoted and the life of pavement prolonged. METHODS : In this study, the crack, plastic deformation, IRI, and SPI values measured using the existing RoadScanner of a corresponding section, as well as the relative dielectric constant values of a lower deck measured using a ground penetrating radar are reduced. The results of a small impact load test are verified by comparing the modulus of elasticity measured. RESULTS : In the Hongjecheon Overpass, when comparing the suspicion points of deterioration between the center of the lane and the 25 measurement data points of the wheel pass section based on the elastic modulus of the light falling weight deflectometer (LFWD), it is discovered that the lane comprises four centers (16%) and 18 wheelpaths (72%). The percentage of suspected deterioration points in the center is higher than that in the wheelpath. In addition, in the case of the Seoho Bridge, by comparing the suspicious points of deterioration for 11 measurement data points in the middle of the lane and the wheelpath section based on the elastic modulus of the LFWD, it is discovered that five points (45%) in both the middle of the lane and the wheel pass are similar. CONCLUSIONS : In this study, a comparative analysis of the LFWD elastic modulus and SPI factors (crack rate, plastic deformation, and IRI) of the Hongjecheon Overpass and Seoho Bridge is conducted to confirm the factors of pavement breakage. Among them, it is confirmed that it affects the pavement condition the most; however, to consider the LFWD elastic modulus as an evaluation criterion for future structure pavement, the data points must be verified via additional experiments to ensure high reliability.

This study was conducted to investigate growth characteristics of paprika seedlings according to various qualities of LED light (red : blue = 10 : 0, red : blue = 8 : 2, red : blue = 2 : 8, white). Plant height and stem were significantly longer or thicker as red light ratio increased. Leaf area of paprika seedlings with red light was larger or no significant differences in a mixed light of red and blue. Dry weight of seedling was in the same with the result of leaf area. Seedlings with White light was significantly less than others in all characteristics. As red light ratio was increased, relative growth rate increased. As blue light ratio was increased, the net assimilation amount increased. Considering plant height, leaf area and production ability of dry matter per unit leaf area, the using mixed red and blue lights was suitable, especially at a mixed red : blue = 8 : 2.

Uniform scions and rootstocks should be produced to ensure grafting success. Light quality is an important environmental factor that regulates seedling growth. The effects of warm- and cool-white light emitting diode (LED) ratios on seedling growth were investigated. Scions and rootstocks of cucumber, tomato, and watermelon were grown in a closed transplant production system using LED as the sole lighting source. The LED treatments were W1C0 (only warm-white), W1C1 (warm-white: cool-white = 1:1), W3C1 (warm-white: cool-white = 3:1), and W5C2 (warm-white: cool-white = 5:2). The seedlings grown in W1C1 had the shortest hypocotyls, and the seedlings grown in W1C0 had the longest hypocotyls among the three tested vegetables. The hypocotyls of watermelon scions, watermelon rootstocks, and tomato rootstocks were shortest in W1C1, followed by those in W3C1, W5C2, and W1C0, but there was no significant difference between W3C1 and W5C2, which remained the same as the ratio of cool-white LEDs increased. In addition, tomato scions had the first and second longest hypocotyls in W1C0 and W3C1, respectively, and the shortest hypocotyls in W5C2 and W1C1, along with W5C2 and W1C1, although the difference was not significant. The stem diameter was highest in W1C0 except for tomato seedlings and rootstocks of watermelon. The shoot fresh weight of scions and rootstocks of cucumber and watermelon and the root fresh weight of cucumber scions were lowest in W1C1. These results indicated that different ratios of LED lighting sources had a strong effect on the hypocotyl elongation of seedlings.

Bullets flying with a light from the back are called “tracers”. Tracers are ignited by the combustion gas of the propellant and emit bright light that allows the shooter to visually trace the flight path. Therefore, tracers mark the firing point for allies to assist shooters to hit target quickly and accurately. Conventional tracers are constructed with a mixture of an oxidizing agent, raw metal, and organic fuel. Upon ignition, the inside of the gun can be easily contaminated by the by-products, which can lead to firearm failure during long-term shooting. Moreover, there is a fire risk such as forest fires due to residual flames at impact site. Therefore, it is necessary to develop non-combustion type luminous material; however, this material must still use the heat generated from the propellant, so-called “thermoluminescence (TL)”. This study aims to compare the TL emission of Dy3+, La3+ and Ho3+ doped MgB4O7 phosphors prepared by solid state reaction. The crystal structures of samples were determined by X-ray diffraction and matched with the standard pattern of MgB4O7. Luminescence of various doses (200 ~ 15,000 Gy) of gamma irradiated Dy3+, La3+ and Ho3+ (at different concentrations of 5, 10, 15 and 20 %) doped MgB4O7 were recorded using a luminance/color meter. The intensity of TL yellowish (CIE x = 0.401 ~ 0.486, y = 0.410 ~ 0.488) emission became stronger as the temperature increased and the total gamma-ray dose increased.

A 1.8 μm thick polycrystalline diamond (PCD) thin film layer is prepared on a Si(100) substrate using hot-filament chemical vapor deposition. Thereafter, its thermal conductivity is measured using the conventional laser flash analysis (LFA) method, a LaserPIT-M2 instrument, and the newly proposed light source thermal analysis (LSTA) method. The LSTA method measures the thermal conductivity of the prepared PCD thin film layer using an ultraviolet (UV) lamp with a wavelength of 395 nm as the heat source and a thermocouple installed at a specific distance. In addition, the microstructure and quality of the prepared PCD thin films are evaluated using an optical microscope, a field emission scanning electron microscope, and a micro-Raman spectroscope. The LFA, LaserPIT-M2, and LSTA determine the thermal conductivities of the PCD thin films, which are 1.7, 1430, and 213.43 W/(m·K), respectively, indicating that the LFA method and LaserPIT-M2 are prone to errors. Considering the grain size of PCD, we conclude that the LSTA method is the most reliable one for determining the thermal conductivity of the fabricated PCD thin film layers. Therefore, the proposed LSTA method presents significant potential for the accurate and reliable measurement of the thermal conductivity of PCD thin films.

To build a highly active photocatalytic system with high efficiency and low cast of TiO2, we report a facile hydrothermal technique to synthesize Ag2Se-nanoparticle-modified TiO2 composites. The physical characteristics of these samples are analyzed by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy and BET analysis. The XRD and TEM results show us that TiO2 is coupled with small sized Ag2Se nanoplate, which has an average grain size of about 30 nm in diameter. The agglomeration of Ag2Se nanoparticles is improved by the hydrothermal process, with dispersion improvement of the Ag2Se@TiO2 nanocomposite. Texbrite BA-L is selected as a simulated dye to study the photodegradation behavior of as-prepared samples under visible light radiation. A significant enhancement of about two times the photodegradation rate is observed for the Ag2Se@TiO2 nanocomposite compared with the control sample P25 and as-prepared TiO2. Long-term stability of Ag2Se@TiO2 is observed via ten iterations of recycling experiments under visible light irradiation.

The purpose of this study is to analyze the effect of temperature and humidity on the measured Particulate Matter (PM) concentrations recorded by PMS5003T, a low-cost light scattering type measuring tool. A regression analysis was performed on the ratio of PM concentrations measured by the light scattering method and the beta-ray absorption method according to temperature and humidity in an outdoor environment. As the temperature decreased, the PM concentration ratio increased, and this tendency intensified below 0oC. As the humidity increased, the PM concentration ratio increased, but the effect was less than the temperature effect. The coefficients of determination for temperature and humidity were R2 = 0.325 and 0.003, respectively, and the effects of temperature and humidity on the measured values w ere formulated and compensated for. As a result of the compensation, R2, relative precision, accuracy and RMSE improved from 0.927 to 0.958, from 91.183% to 96.651%, from 31.383% to 74.058%, and from 13.517 μg/m³ to 6.690 μg/m³, respectively. Finally, results from this study indicate that the reliability of the low-cost light scattering type PM sensor can be improved by applying the temperature and humidity compensation method.