• Korean Journal of Organic Agriculture
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• v.17 no.3
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• pp.371-380
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• 2009

This study was conducted to assess effects of supplying different types of nitrogen sources as fertilizers on productivity and feed values of barley and rye as winter forage crops, and ultimately done to get good quality of organic forages with higher fertilization of soil. For barley, N+P+K plots were significantly (P<0.05) higher in annual dry matter (DM) and total digestible nutrients (TDN) yields than other plots. However, cattle manure plots had significantly (P<0.05) higher annual DM and TDN than P+K and non-fertilizer plots. Plots of 50%-cattle manure and mixed sowing with hairy vetch or forage pea were higher than only 50%-cattle manure plot, particularly, these were significantly higher than non-fertilizer, and their crude protein (CP) yields were much higher than other plots. Crude protein contents were significantly higher in N+P+K and 50%-cattle manure slurry plots than non-fertilizer and P+K plots, and plots of mixed sowing with hairy vetch or forage pea in application of 50%-cattle manure had higher CP content than other plots. ADF content was lowest in 50%-cattle manure+forage pea plots, but highest in 100%-cattle manure plots. NDF content was lowest in legumes-mixed sowing, but highest in 100%-cattle manure plots. TDN content was the highest in forage pea plots, and plots of 50%-cattle manure and legumes-mixed sowing had high RFV, but cattle manure plots rich in ADF and NDF content had the lowest TDN and RFV. For rye, plots of 50%-cattle manure+hairy vetch mixed sowing, and N+P+K application had significantly higher annual DM, CP and TDN than other plots except for cattle manure. DM productive efficiency to nitrogen fertilization was markedly higher for cattle manure plots than for chemical fertilizer. This tendency was more conspicuous in plots of 50% cattle manure+legumes-mixed sowing. CP content was higher for N+P+K plot than for all plots, and plots of 50%-cattle manure + legumes-mixed sowing were significantly higher than other plots. On the contrary, forage pea-mixed sowing plot had the lowest ADF and NDF, but TDN and RFV were significantly (P<0.05) higher than other plots. Grass crop cultivation together with legumes by applying livestock manure to soil may lead to higher palatability of livestock, and better quality of forage. Furthermore, cattle manure application increased production yield per ha and CP contents. Thus, when applying forage crops produced by cattle manure application and mixed sowing to organic livestock production, it was conceived that forages produced might become a substitute for foreign organic grain as protein sources.

• Journal of the Korean Geotechnical Society
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• v.34 no.7
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• pp.29-38
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• 2018

Three-dimensional continuum modeling of dynamic soil-pile-structure interaction embedded in a liquefiable sand was carried out. Finn model which can model liquefaction behavior using effective stress method was adopted to simulate development of pore water pressure according to shear deformation of soil directly in real time. Finn model was incorporated into Non-linear elastic, Mohr-Coulomb plastic model. Calibration of proposed modeling method was performed by comparing the results with those of the centrifuge tests performed by Wilson (1998). Excess pore pressure ratio, pile bending moment, pile head displacement-time history according to depth calculated by numerical analysis agreed reasonably well with the test results. Validation of the proposed modeling method was later performed using another test case, and good agreement between the computed and measured values was observed.

• Resources Recycling
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• v.16 no.5
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• pp.36-40
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• 2007

Platinum plays an important role in many applications because of its extraordinary physical and chemical properties. All these applications require the use of platinum in the finely divided state. Therefore the preparation of platinum nanoparticles by reducing platinum-surfactant salt with reducing agent in the solution was investigated in this study. The net interaction between C14TABr and $H_2[PtCl_6]$ in aqueous solution results in the formation of $[C14TA]_2[PtCl_6]$. The concentration of C14TABr and the concentration of $H_2[PtCl_6]$ has to be above cmc and 0.32 mM, respectively in order to obtain complex-micelle aggregation for mono dispersed Pt particles. Pt particle size increases with increasing $H_2[PtCl_6]$ and C14TABr concentration. And the shape of Pt particles was well controlled with increasing surfactant concentration.

• Membrane Journal
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• v.8 no.4
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• pp.228-234
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• 1998

Among various water contaminents, organic compounds like phenol are difficult to be removed or destroyed by conventional methods under the unusual discharge conditions. The separation of phenol from aqueous solution has been carried out by several methods recently: absorption by an activated carbon, solvent extraction and liquid membrane technology. The liquid membrane based on water-oil emulsification has been tested as an alternative technology of the conventional technology. In this work, tri-n-butyl phosphate(TBP) and liquid polymers were examined as a liquid membrane in the supported liquid membrane(SLM). The feed concentration of phenol was varied and various types of liquid membranes were used to examine their effects on separation of phenol. It was found that TBP, polypropylene glycol 4000(PPG 4000) and polybutytene glycol 500(PBG 500) were proper carriers because mass transfer rates through them were much higher than or similar to that through methyl isobutyl ketone(MIBK) which was used as a conventional solvent in a solvent extraction process.

• Composites Research
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• v.35 no.6
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• pp.456-462
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• 2022

Since natural fibers are highly flammable, it is not easy to make them flame retardant. In this study, a liquid flame retardant based on phytic acid, APTES, and Thiourea, which are flame retardant candidates derived from nature, was prepared and its performance was verified through flame retardant treatment and flame retardancy evaluation of bamboo fibers. When a liquid flame retardant is used, it is possible to treat a large amount of natural fibers with flame retardant treatment. Nine types of flame-retardant treated bamboo fibers were prepared according to the Taguchi design of experiment method. Thereafter, vertical burning test and microcalorimeter test were performed for flame retardancy evaluation, and the surface of natural fibers before and after flame-retardant treatment was compared using scanning electron microscope. The results show that phytic acid has a significant effect on improving the flame retardancy of natural fibers. Through microstructure analysis, it was assumed that the phytic acid helps flame retardant to uniformly adhere to the surface of natural fibers. If such research results are utilized, it is possible to make a large amount of natural fibers high flammability in an eco-friendly way, which is expected to be advantageous for the application of prototypes.

• Journal of Welding and Joining
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• v.13 no.2
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• pp.132-138
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• 1995

Rene80 superalloy was liquid phase diffusion bonded by using boron(B) as an insert material, where B has high diffusivity and higher melting point as an insert material. Bonding procedure and bonding mechanism of Rene80/B/Rene80 joint were investigated. As results, liquid metal was produced by solid state reaction between base metal and insert material on bonding zone. The liquid metal was produced preferentially at the grain boundary. Except for production of liquid metal, other bonding procedure was nearly same as TLP(Transient Liquid Phase) bonding. Bonding time, however, was reduced compared to prior result of TLP bonding. By bonding S.4ks at l453K, Ren80/B/Rene80 joint was isothermally solidified and homogenized where thickness of insert material was 7.5.mu.m.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.193-198
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• 2000

분무건조장치는 Solution, Slurry, Emulsion, Colloidal Suspension 등의 액상원료를 미립화하여 표면적을 증가시켜 수열면적을 크게 하여 열풍과 직접 접촉함으로써 순간적으로 건조를 행하여 액상원료로부터 바로 분립상의 제품을 얻는 건조법이다. 분유를 비롯하여 Instant 식품류, 합성세제, 염료, 안료, Ceramic, 공해 폐액의 처리에 이르기까지 폭넓게 이용되고 있다. 분무건조기는 통기, 회전, 기류 건조기 등 다른 건조기에 비하여 고도의 설계 및 제작 기술을 요하며, 설계에 있어서 일부 이론적인 취급이 행해지고 있는 것은 사실이나 아직은 경험에 의존하고 있는 현실이다. 국내에서 제작되고 있는 분무건조기의 열효율은 25-33%로 선진국의 35-48%에 비해 매우 낮다. 국내에서 사용되고 있는 분무건조기의 92%는 덴마크, 일본 등에서 수입된 것이다.(중략)

• Journal of Powder Materials
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• v.18 no.4
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• pp.332-339
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• 2011

Cemented tungsten carbide has been used in cutting tools and die materials, and is an important industrial material. When the particle size is reduced to ultrafine, the hardness and other mechanical properties are improved remarkably. Ultrafine cemented carbide with high toughness and hardness is now widely used. The objective of this study is synthesis of nanostructured WC-Co powders by liquid phase method of tungstate. The precursor powders were obtained by freezen-drying of aqueous solution of soluble salts, such as ammonium metatungstate, cobalt nitrate. the final compositions were WC-10Co. In the case of liquid phase method, it can be observed synthesis of WC-10Co. The properties of powder produced at various temperature, were estimated from the SEM, BET and C/S analyser.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.213-217
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• 1995

Infrared Spectra of aqueous solution of BUDDA(Butyldithiodiacetic acid), BMDDA(Benzmethyldithiodiacetic acid), and CHDDA(Cyclohexyldithiodiacetic acid) are reported at various pH values. On the basis of the antisymmetric stretching bands of the ionized and un-ionized carboxyl group, the structures of the free-ligand are inferred. An approach to the study of these structures are compared with the results of potentiometric titration curve and IR Spectra studies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1082-1091
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• 1989

본 논문에서는 응고계면을 기준으로 하여 액상역, 고상역 및 로울등을 각각 계산 가능한 영역으로 좌표변환하는 경계공정법을 사용하여 로울두께 방향의 온도분 포와 고상역과 액상역의 속도 분포를 고려한 2차원 응고해석을 하여 모델재료를 이용 한 실험결과와 비교 검토하여 이론해석의 타당성을 검정한다. 그리고 열전도율이 연 강보다 적어 박판제조가 어려운 재료인 스테인리스강을 용탕으로부터 직접 생산하기 위한 압연조건을 정량적으로 제시하며, 압연로울의 냉각특성을 밝힌다.