• Title/Summary/Keyword: Drying Method

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A Study on the Development of Non-PC High-Early-Strength Concrete Without Steam Curing (증기양생이 불필요한 PC부재용 조강형 콘크리트 개발에 관한 연구)

  • Jun, Woo-Chul;Lee, Ji-Hwan;Park, Hee-Gon;Lee, Jae-Sam;Kim, Kyung-Min;Cho, In-Sung
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.2
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    • pp.156-162
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    • 2014
  • This study aims to develop a rapidly hardening type of concrete to achieve the removal of form intensity (more than 10MPa) using the method of curing at room temperature in order to solve some economic environmental problems by omitting the steam curing process involved in producing PC (Precast Concrete). Therefore, this study evaluated a rapidly hardening cement containing a high amunt of C3S, which is very responsive in expressing early intensity, and a rapidly hardening type of concrete which uses some hardening accelerator to increase thehydration reaction of $C_3S$. The results of the experiment on concrete using some hardening accelerator are asfollows. In the slump flow experiment for identifying the liquidity and the air test, the desired values were met. The compression strength showed rapid expression response by 12 hours, and met the desired value within 6~9 hours. Its drying shrinkage value and Autogenous shrinkage value were measured as below ($-754.5{\times}10^{-6}$),and satisfied the requirements. In addition, in the Semi-Adiabatic Temperature Test, it was found that the concrete rose to its peak temperature within 24 hours and then its temperature dropped.

CuO Nanograss as a Substrate for Surface Enhanced Raman Spectroscopy

  • Lee, Jun-Young;Park, Jiyun;Kim, Jeong-Hyun;Yeo, Jong-Souk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.249-249
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    • 2013
  • Surface-enhanced Raman spectroscopy (SERS) is a sensitive approach to detect and to identify a variety of molecules. To enhance the Raman signal, optimization of the gap between nanostructures is quite important. One-dimensional materials such as nanowires, nanotubes, and nanograsses have great potential to be used in SERS due to their unique sizes and shape dependent characteristics. In this study we investigate a simple way to fabricate SERS substrates based on randomly grown copper oxide (CuO) nanowires. CuO nanograss is fabricated on pre-cleaned Cu foils. Cu oxidized in an ammonium ambient solution of 2.5 M NaOH and 0.1 M $(NH_4)_2S_2O_8$ at $4^{\circ}C$ for 10, 30, and 60 minutes. Then, Cu(OH)2 nanostructures are formed and dried at $180^{\circ}C$ for 2 h. With the drying process, the Cu(OH)2 nanostructure is transformed to CuO nanograss by dehydration reaction. CuO nanograss are grown randomly on Cu foil with the average length of 10 ${\mu}m$ and the average diameter of a 100 nm. CuO nanograsses are covered by Ag with various thicknesses from 10 to 30 nm using a thermal evaporator. Then, we immerse uncoated and Ag coated CuO nanowire samples of various oxidation times in a 0.001M methanol-based 4-mercaptopyridine (4-Mpy) in order to evaluate SERS enhancement. Raman shift and SERS enhancement are measured using a Raman spectrometer (Horiba, LabRAM ARAMIS Spectrometer) with the laser wavelength of 532 nm. Raman scattering is believed to be enhanced by the interaction between CuO nanograss and Ag island film. The gaps between Ag covered CuO nanograsses are diverse from <10 nm at the bottom to ~200 nm at the top of nanograsses. SERS signal are improved where the gaps are minimized to near 10s of nanometers. There are many spots that provide sufficiently narrow gap between the structures on randomly grown CuO nanograss surface. Then we may find optimal enhancement of Raman signal using the mapping data of average results. Fabrication of CuO nanograss based on a solution method is relatively simple and fast so this result can potentially provide a path toward cost effective fabrication of SERS substrate for sensing applications.

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Screening of Antioxidant Activity in Dansam(Salvia miltiorrhiza) and Additional Effect on the Shelf-Life and the Characteristics of Yakgwa (단삼추출물의 항산화능 검색 및 약과에의 첨가효과)

  • 김윤화;한영실;백재은;송태희
    • Korean journal of food and cookery science
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    • v.19 no.4
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    • pp.463-469
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    • 2003
  • This study was carried out to investigate the antioxidant activities of Dansam (S. miltiorrhiza). The Dansam (S. miltiorrhiza) was extracted with ethanol and methanol, and the extracts were fractionated with hexane, chloroform, ethyl acetate and butanol and water, in that order. The antioxidant activities of Dansam (S. miltiorrhiza) were determined by measuring the radical scavenging effects, using the 1, l-diphenyl-2-picryl-hydrazyl (DPPH) method. The electron donating ability was shown to be about 50% (IC50) at concentration of L-ascorbic acid, Dansam that reflected eliminatory effect by 50% were 9.48$\mu\textrm{g}$/$m\ell$, 8.28$\mu\textrm{g}$/$m\ell$, and l2.59$\mu\textrm{g}$/$m\ell$ respectively. According to the results of the above anti oxidation experiments, those for the group with the added Dansam showed a decreased oxidation, but the antioxidation increased with time. With a storage temperature of 60 C for 5 days, the acid value for the relative antioxidant activities were higher than in the Control group. The peroxide values for the relative antioxidant activities were also higher than in the Control group. The TBA values for the relative antioxidant activities were higher than in the Control group.

Quality Characteristics of Loaf Bread Added with Takju Powder (탁주 분말을 첨가한 식빵의 품질 특성)

  • Jeong, Jin-Woong;Park, Kee-Jai
    • Korean Journal of Food Science and Technology
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    • v.38 no.1
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    • pp.52-58
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    • 2006
  • Characteristics of dough added with up to 4.0% takju powder and resultant bread were studied. Doughs added with takju power spray-dried after fermentation with starter (SDWS) and takju power spray-dried after fermentation without starter (SDOS) showed higher pH decreases than those added with takju power freeze-dried after fermentation with starter (FDWS) and takju power freeze-dried after fermentation without starter (FDOS) even after 1st fermentation. After 1st fermentation, volume of dough added with 1-4% SDWS was high, with 1% SDWS showing highest value of 23.6 mL. Volume of bread added with SDOS showed highest value. At 1-2% SDWS and SDOS addition, doughs showed highest specific volume values, which decreased at higher than 3% addition, while specific volume increased with increasing FDWS and FDOW contents. L values of SDOS- and FDOS-added doughs decreased gradually with increasing SDOS and FDOS contents compared to SDWS and FDWS addition. In loaf bread added with takju powder less than 2%, loaf bread added with spray-dried takju powder had higher appearance, color, texture, taste, and overall acceptability values compared to those added with freeze-dried takju. Although not significantly, loaf bread added with 1% SDWS showed slightly higher values in appearance, color, yeastiness, texture, taste, and overall acceptability, and showed higher flour odor acceptability than non-added loaf bread. These results indicate addition of takju powder improves flavor of bread.

Study of Dried Korean Native Plants Using for Floral Clusters (건조 자생식물 종별 꽃다발 이용 가능성 검토)

  • Sohn, Kwanhwa;Kwon, Hye Jin
    • FLOWER RESEARCH JOURNAL
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    • v.16 no.4
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    • pp.266-274
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    • 2008
  • Korean native plants were investigated for their suitability to be used for floral clusters after drying. Floral clusters which were made in semi-sphere with a hand-tied method and can be fit in $22{\times}22{\times}37cm$ paper boxes were made with 37 species. Among 37 species, the 14 species which were easy to dry, to make floral clusters, and have not been used in other countries, were Echinochloa crus-galli var. frumentacea, Imperata cylindrica var. koenigii, Muhlenbergia huegelii, Phleum pratense, Setaria glauca, and Setaria viridis in Gramineae, Artemisia capillaris, Artemisia montana, and Chrysanthemum indicum in Compositae, Agastache rugosa, Elsholtzia ciliata, Elsholtzia splendens in Labiatae, Carex neurocarpa in Cyperaceae, and Vitex rotundifolia in Verbenaceae were used with leaves, flowers, and fruits. The suitable plants for a floral cluster in $22{\times}22{\times}37cm$ paper box, a wreath in $22{\times}22{\times}6cm$ paper box, and a flower arrangement in $22{\times}22{\times}22cm$ paper box, which were made to a set, were 10 species, that is Phragmites communis, Setaria glauca, Setaria viridis, Artemisia capillaris, Artemisia montana, Chrysanthemum indicum, Elsholtzia ciliata, Elsholtzia splendens, Mosla punctulata, and Vitex rotundifolia.

Physicochemical quality characteristics of hot water extracts of processed ginseng based on different heat treatments (열처리 방법에 따른 가공 인삼 열수추출물의 이화학적 품질 특성)

  • Kang, Yoon-Han;Zhou, Rui;Kim, Hyo Jin;Kim, Ji Eun;Shin, Il Shik
    • Food Science and Preservation
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    • v.25 no.1
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    • pp.155-163
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    • 2018
  • The present study was carried out to investigate the physicochemical properties of hot water extracts of red ginseng powder prepared by two-stage hot air drying method using steamed ginseng and steaming liquid for 2.5 h under high-temperature and high-pressure autoclave condition. The total polyphenols, total flavonoids, total sugar, acid polysaccharides and crude saponin in hot water extracts from red ginseng powder were analyzed and determined, and the flavor components of ginseng were measured using color difference meter and an electronic tongue. The total polyphenol, total flavonoid, total polysaccharide, and acid polysaccharide of the red ginseng hot water extract obtained by autoclaving (ARG) were 9.06 mg GAE/g, 3.38 mg NE/g, 35.22 g/100 g, and 10.90 g/100 g, respectively. The final contents of the total polyphenols, total flavonoids, crude saponin were higher than those determined using other red ginseng methods; the time required for steamed red ginseng production reduced. The total ginsenoside content of ginseng including Rb1 was 10.69 mg/g, which is the lowest ARG. The processing conditions affected the conversion to ginsenosides unique to red ginseng. Red ginseng and steaming liquid obtained from the autoclave are expected to be in need for non-food materials and products as well as foods by improving the flavor components through conversion of red ginseng components into low molecular weight.

Granulation of Fine Zeolite Powder by Adding Polyvinyl Alcohol (Polyvinyl Alcohol첨가(添加)에 의한 Zeolite미분(微粉)의 입상화(粒狀化))

  • Choi, Jyung;Choi, Choong Ryeol;Lee, Dong Hoon
    • Korean Journal of Soil Science and Fertilizer
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    • v.28 no.2
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    • pp.123-129
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    • 1995
  • For the propose of increasing the value added, zeolite powder was granulated by adding Polyvinyl Alcohol (PVA) as cementing material. The optimal concentration of PVA for granulation and the physical properties of the prepared granule were investigated. Four percent PVA stock solution was made by adding distilled water at $90^{\circ}C$ water bath and incorporated with zeolite. The contents of water stable granule above 2.0mm in diameter was 98.0% in the case of 0.3% PVA addition and almost 100% in the case of 0.6% PVA addition. Increasing PVA concentration of granules increased the hardness and decreased the infiltration rate and the maximum water holding capacity of granules, However, the drying method hardly affected the physical properties of granules. With the increase in the mixing ratios of kaolinite or bentonite to zeolite, the hardness of granules increased but high water contents of granules resulted in rapid decrease in the hardness of granules. However, when smectite or perlite was mixed with zeolite, the increase in mixing ratios to zeolite resulted in the decrease in hardness, the increase in the infilteration rate and maximum water holding capacity of granules.

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Comparison of Kernel Sample Preparation Methods at Different Grain Filling Periods for Determining Pericarp Thickness in Super Sweet and Waxy Corn Hybrids (시료 준비 방법에 따른 등숙 시기별 초당 및 찰옥수수 교잡종의 과피 두께 비교)

  • Han, Seong-Jin;Oh, Tae-Yeung;Kang, Min-jeong;Kang, Jong-won;Wang, Seung-hyun;Park, Tai-choon;Kang, Geon;Chung, Jong-Wook;So, Yoon-Sup
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.64 no.2
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    • pp.102-108
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    • 2019
  • Pericarp thickness of vegetable corns such as sweet and waxy corn is one of the crucial traits, contributing to their edible quality. This study was carried out to compare the pericarp thickness of super sweet and waxy corn hybrids measured with kernel samples prepared using different methods at different grain filling periods. The samples comprised excised pericarp from dried, frozen (at $-4^{\circ}C$), and fresh kernels. Analysis of variance performed separately on super sweet and waxy corn hybrids indicated a significant three-way interaction among cultivars, kernel sample preparation methods, and days after pollination (DAP). Dried samples of super sweet corn hybrids presented reasonably stable pericarp thickness measurements during grain filling, while all the sample preparation methods fluctuated less as grains of waxy corn hybrids matured. Waxy corn is best consumed at around 24 days after pollination. Pericarp thickness of waxy kernel samples regardless of preparation methods investigated was the same at 24 DAP with a few exceptions. Overall, the common method of drying kernel samples before pericarp excision can provide reliable data for estimating the tenderness of vegetable corn hybrids.

Effect of the Application of Hand Washing Education Program for the Children with Intellectual Disability on Hand Washing Frequency and Methods during COVID-19 Pandemic (코로나-19 확산 속에서 손 씻기 교육 프로그램 적용이 지적장애 아동들의 손 씻기 빈도와 방법에 미치는 영향)

  • Son, Sung-Min;Kwag, Sung-Won
    • Journal of the Korean Applied Science and Technology
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    • v.37 no.6
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    • pp.1659-1668
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    • 2020
  • The purpose of this study is to analyze the effect of the application of hand washing education program for the children with intellectual disability on hand washing frequency and methods during COVID-19 Pandemic. Subjects were 14 children with intellectual disability and they participated in the program using visual video materials. Hand washing education program was consisted of introduction, theory education, and practice and it performed 2 times a week, total 16 sessions during 8 weeks. Hand washing theory education was consisted about the importance and application of hand washing, proper hand washing steps and methods, use of hand washing tools, use of hand sanitizers including characteristics, and prevention of skin damage from hand washing. Hand washing assessment was used by hand washing frequence and methods observation report. Hand washing frequency was measured by the hand washing frequency during the daily routine and it was analyzed by the items divided into day and month units. Hand washing methods was measured by the items divided into use of hand washing tools, time, areas, drying methods after hand washing. As the results, after hand washing education program, the hand washing frequence was increased and hand washing methods were improved. Hand washing is much important as a active method to prevent the infection during the COVID-19 Pandemic. Thus, based on this findings, the application of hand washing education program should be considered to increase the hand washing frequency and improve the hand washing methods of the children with intellectual disability.

ITZ Analysis of Cement Matrix According to the Type of Lightweight Aggregate Using EIS (EIS를 활용한 경량골재 종류별 시멘트 경화체의 계면특성 분석)

  • Kim, Ho-Jin;Jung, Yoong-Hoon;Bae, Je-Hyun;Park, Sun-Gyu
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.4
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    • pp.498-505
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    • 2020
  • Aggregate occupies about 70-85% of the concrete volume and is an important factor in reducing the drying shrinkage of concrete. However, when constructing high-rise buildings, it acts as a problem due to the high load of natural aggregates. If the load becomes large during the construction of a high-rise building, creep may occur and the ground may be eroded. Material costs increase and there are financial problems. In order to reduce the load on concrete, we are working to reduce the weight of aggregates. However, artificial lightweight aggregates affect the interface between the aggregate and the paste due to its higher absorption rate and lower adhesion strength than natural aggregates, affecting the overall strength of concrete. Therefore, in this study, in order to grasp the interface between natural aggregate and lightweight aggregate by type, we adopted a method of measuring electrical resistance using an EIS measuring device, which is a non-destructive test, and lightweight bone. The change in the state of the interface was tested on the outside of the material through a blast furnace slag coating. As a result of the experiment, it was confirmed that the electric resistance was about 90% lower than that in the air-dried state through the electrolyte immersion, and the electric resistance differs depending on the type of aggregate and the presence or absence of coating. As a result of the experiment, the difference in compressive strength depending on the type of aggregate and the presence or absence of coating was shown, and the difference in impedance value and phase angle for each type of lightweight aggregate was shown.