• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.932-941
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• 1993

High moisture content of barley seeds, which were carried to the laboratory within 10 minutes after harvest, were stored in air tight bottle at constant temperature, and the individual moisture contents the grains were measured at predecided tim intervals. The theory of predicting the moisture movement between two kinds of different moisture content grains was tried to apply to the prediction of the moisture distribution and tried to apply to the prediction of the moisture distribution and the comparison of the predicted values with the observed dta showed the good suitability of the theory. The shape of the moisture distribution predicted form the theory were similar to the observed ones for the temperature range of 10 to $50^{\circ}C$. This study will be useful in designing the mix-storage facility or dryer.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3733-3737
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• 2013

Polyacrylonitrile (PAN)-based ultrafine fibers and carbon fibers were produced by wet-spinning, and the crystal sizes and thermal and mechanical properties of the fibers were investigated. Scanning electron microscopy revealed that the superfine fibrils in the surfaces of the PAN/polyvinyl acetate (PVA) blend fibers increased slightly with increasing PAN content before removal of the PVA. Differential scanning calorimetry indicated that the PAN and PVA in the blend fibers do not mix and, therefore, each maintains their inherent thermal characteristics. The crystal sizes of the blend fibers prepared by removing PVA with water increased at 5 wt % water. The extent of the reaction of the PAN carbon fibers, as calculated from the FT-IR spectra, is maximized at the stepwise temperature of $230^{\circ}C$, and the density increased significantly above this temperature. The carbon fibers had relatively good mechanical properties, as shown by their tensile strength and modulus values of 2396 MPa and 213 GPa, respectively.

• 콘크리트학회논문집
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• 제12권1호
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• pp.113-125
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• 2000

The purpose of this study was to examine the durability characteristics of controlled low strength material(flowable fill) with high volume fly ash content. Flowable fill refer to self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. The two primary advantages of flowable fill over traditional methods are its ease of placement and the elimination of settlement. Therefore, in difficult compaction areas or areas where settlement is a concern, flowable fill should be considered. The fly ash used in this study met the requirements of KS L 5405 and ASTM C 618 for Class F material. The mix proportions used for flowable fill are selected to obtain low-strength materials in the 10 to 15kgf/$\textrm{cm}^2$ range. The optimized flowable fill was consisted of 60kg f/$\textrm{m}^3$ cement content, 280kgf/$\textrm{m}^3$ fly ash content, 1400kgf/$\textrm{m}^3$ sand content, and 320kgf/$\textrm{m}^3$ water content. Subsequently, durability tests including permeability, warm water immersion, repeated wetting & drying, freezing & thawing for high volume fly ash-flowable fill are conducted. The results indicated that flowable fill has acceptable durability characteristics.

• Advances in concrete construction
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• 제6권1호
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• pp.87-102
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• 2018

Utilization of waste tires may be considered as one of the solution to the problems faced by the local authorities in disposing them. Reclaimed rubber (RR) is being used in concrete for replacing conventional aggregates. This research work is focused on the strength prediction of reclaimed rubber concrete using a Genetic Algorithm (GA) for M40 grade of concrete and comparing it with experimental results. 1000 sets were taken and 100 iterations were run during training of GA models. A base study has been carried out in this research work partially replacing cement with three types of fillers such as Plaster of Paris (POP), Fly Ash (FA) and Silica Fume (SF). A total of 243 cubes were cast and tested for compression using a Universal Testing Machine. It was found that SF produced maximum strength in concrete and was used in the main study with reclaimed rubber. Tests were conducted on 81 cube samples with a combination of optimum SF percent and various proportions of RR replacing coarse aggregates in concrete mix. Compressive strength tests of concrete at 7, 14 and 28 days reveal that the maximum strength is obtained at 12 percent replacement of cement and 9 percent replacement of coarse aggregates respectively. Moreover the GA results were found to be in line with the experimental results obtained.

• 대한안전경영과학회지
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• 제16권3호
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• pp.327-333
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• 2014

Changes in the business environment in which intense and sustained growth and survival must meet a variety of customer needs (Q, C, D) and business side of the enterprise for profit structure reformation is absolutely necessary for innovation activities. So far, management of innovation in method BPR, PI, OVA, 6 Sigma, Strategic Purchasing, PPM, SCM etc. are being introduced. However, they have a limit of partial optimization and improvement-oriented techniques. So this paper studied the TPI(Total Profit Innovation) application in order to derive empirical methodology to maximize profitability for the domestic S foundry factory. To this end, long-term gains through structural analysis and intensity analysis to ensure continued growth and profitability strategy are devised through management Innovation analysis. And improvement projects was presented to solve main issues of five categories(Inventory, Sales Mix, Cost, Quality Cost, Skill and Work-load) We will expect the office productivity improvement and financial performance improvement and then continually accumulate and review the results.

• 한국세라믹학회지
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• 제45권12호
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• pp.815-820
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• 2008

The microstructure and mechanical properties of $TiB_2/Si$ nanocomposites based on the Ti-Si-B system, consolidated by spark plasma sintering of mechanically alloyed activated nanopowders, have been characterized. Mechanical Alloying was carried out in a planetary ball mill for 180 min with 350 rev $min^{-1}$. The powders were pressed in vacuum at a pressure of 60 MPa, generating a maximum temperature in the graphite mould of $1400^{\circ}C$. Analysis of the synthesized nanocomposites by SEM, XRD and TEM showed them to consist of $TiB_2$ second phase, sub-micron in size, with no third phase. Composites consolidated from powders mechanically alloyed from an initial elemental powder mix of 0.3 mol Si, 0.7 mol Ti, and 2.0 mol B achieved the best relative density (97%) and bending strength (774 MPa); the highest Vickers hardness of 14.7 GPa was achieved for the 0.1-0.9-2.0 mol starting composition.

• 한국응용과학기술학회지
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• 제14권2호
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• pp.93-102
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• 1997

Isothiazoline derivatives is widely used to food, medical drug and industrial goods, cosmetics etcs, and it makes to restrain and to sterilize a breeding of microbe as a preservative and a sterilizing agent. It differs with the raw material of paraoxybenzoic acid derivatives or imidazolydinyl urea to be in use at present, on the efficacy and effect, and has various characteristics. This synthesis makes 3,3'-dithiodipropionic chloride to add a thionyl chloride in 3,3'-dithiodipropionic acid, and 3,3'-dithiodipropionic methyl amide makes to synthesize in a reflux reaction the mono methyl amine to 3,3'-dithiodipropionic chloride. And last synthesis becomes to make chlorination-cyclization molecule doing a reflux reaction in the temperature of $90{\sim}100^{\circ}C$ to mix excessively thionyl chloride and ethylene dichloride to 3,3'-dithiodipropionic methyl amide. The last synthesis material has got in the mixture of 5-chloro-2-methyl-4-isothiazoline-3-one and 2-methyl-4-isothiazoline-3-one, and it is so-called isothiazoline derivatives. The purification of isothiazoline derivatives makes to fuse in ethyl acetate, and makes to decolorize and to deodorize in recrystallization. This experiment has been in synthesis and purification of isothiazoline derivatives, and has tried to measure on the antisepsis and sterilization function of microbe according to pH or content change.

• 열처리공학회지
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• 제24권4호
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• pp.209-216
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• 2011

Surface coatings were prepared on SKD11 core mold steel by plasma electrolytic oxidation (PEO). The coatings were investigated about the formation condition of core mold steel. SKD11 were coated by PEO in a mix solution of Sodium Aluminate $NaAlO_2$ (10 g/l), Sodium Silicate powder $Na_2SiO_3$ (0.5 g/l), Sodium tungstate dihydrate $Na_2WO_42H_2O$ (0.5 g/l) at less than $30^{\circ}C$. The electrical condition were voltage : 500~600 V; Pulse : 600~1800 Hz; current density 15~20 $A/dm^2$ various time : 3 min~40 min. The coatings surface morphology, cross-section, friction coefficient, hardness were investigated. The PEO coatings on SKD11 core mold steel showed the extended service life.

• 한국통신학회논문지
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• 제34권10C호
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• pp.975-982
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• 2009

본 논문에서는 저연산, 저지연성을 보장하는 다중 비디오 스트림 흔합 알고리즘을 제안한다. 제안된 알고리즘은 슬라이스기반 H.264/AVC 비디오 스트림들을 화소 도메인에서 혼합하지 않고 압축 도메인에서 신택스 비트스트림 변경에 의해 혼합한다. 혼합을 위한 신택스 비트스트림 변환은 혼합화면을 구성할 비디오 스트림들의 위치에 따라 변경한다. 실험결과 4개 이상의 비디오 스트림들을 고속으로 혼합할 수 있었다. 또한 표준 H.264/AVC를 지원하는 플레이어에서 화질열화 없이 재생할 수 있었다.

• Advances in nano research
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• 제4권3호
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• pp.181-195
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• 2016

Addition of nano-$SiO_2$ (NS) to geopolymer composites has been studied through measurement of compressive strengths, FTIR and XRD analysis. Alumino-silicate materials are coarse aggregate included waste concrete and demolished walls with its cementing binder, cement kiln dust (CKD) used and can possess a pronouncing activation for the geopolymer reaction resulting from the high alkali contents within. Materials prepared at water/binder ratios in a range of 0.30: 0.40 under curing of $40^{\circ}C$ and 100% Relative Humidity (R.H.), while the used activator is sodium hydroxide in the ratio of 2 wt. %. First, CKD is added in the ratio from 10 up to 50 wt., %, and the demolished walls was varied depending on the used CKD content, while using constant ratio of waste concrete (40 wt., %). Second step, depending on the optimum CKD ratio resulted from the first one (40 wt. %), so the control geopolymer mix composed of cement kiln dust, demolished walls and waste concrete in the ratio (40:20:40, wt %). Nano-silica partially replaced waste concrete by 1 up to 8%. Results indicated that, compressive strengths of geopolymer mixes incorporating nano-silica were obviously higher than those control one, especially at early ages and specially with 3%NS.