• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.789-795
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• 1999

In this study, carbon fiber reinforced cement composites(CFRCs) reinforced with short noncircular type carbon fibers were fabricated and properties(drying shrinkage, resistance to freezing and thawing, and fracture toughness) were compared with those of the CFRCs reinforced with circular type carbon fibers. It was found that these properties greatly depended on the shape and length of carbon fibers. The drying shrinkage of CFRCs reinforced with C-type carbon fiber was superior to other CFRCs. This effect was increased with a high aspect ratio of fiber. The resistance to freezing and thawing was increased with the fiber length and fiber volume percent, but there was on remarkable effect to fiber shape. Fracture toughness and resistance to crack propagation of CFRCs reinforced with C-CFs were improved compared with other CFRCs. It was believed that the more absorption of fracture energy into the larger interface caused an increase in fracture toughness and resistance to crack propagation.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.301-306
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• 1990

The Physical and chemical properties or dry acorn starch(DS), detannined acorn starch (DTS) and defatted and detannined acorn starch(Drn) were investigated. Ail acorn starch sample, observed by a scanning electron microscope, showed a hemispherical shape ud its size was about $5{\sim}10{\mu}m$ in diameter. It had a little change on the pasting temperature of DS, DTS and DFTS but peak viscosity of DTS was somewhat higher than that of n. Flow behavior of gelatinized starch pastes showed a pseudoplastic behavior and flow behavior index was lower than unit. The consistency coefficient showed concentraion and temperature dependency. The activation energies of DS, DTS and DFTS were $2.09{\sim}3.58Kcal/g\;{\cdot}\;mol and time dependent characteristic of acorn starch samples showed thixotrpic behavior.

• KSBB Journal
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• v.10 no.1
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• pp.46-54
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• 1995

The physiological characteristics of carrot hairy roots and suspension cells were examined based on their nutritional requirements. Inorganic nutrient (phosphorous and ammonium) requirements of carrot hairy roots were similar to those of suspension cells. Optimal sucrose concentration for the growth of hairy roods (7%) was different from that of suspension cells (3%). Since suspension cells were move easily affected by the environmental condition, e.g., osmotic stress, than hairy roofs which made the suitable growth condition for cells, it can be understood that optimal sucrose concentration for the growth of hairy roots was higher than that for the growth of the suspension cells. To investigate the roles of sucrose on the growth of hairy roots, the effects of sucrose on the fresh weight and dry weight was analysed by the addition of mannitol as an osmolicum. Sucrose acts also as an energy source for hairy roots rather than as an osmotic regulator, since the increase of dry weight was higher than that of fresh weight at the given sucrose concentration.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.51-56
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• 2016

The most widely used glue in a corrugator is starch, which is a natural polymer. This material needs thermal energy to achieve a binding force, so a heating section is installed in a corrugator. However, this heating section can cause quality problems in linerboards and corrugating medium and increase the production cost because of the high cost of fossil resources. Therefore, a new adhesive that provides the binding force at lower temperatures than the conventional one must be developed. In this study, SB-latex was selected as a co-adhesive and added to the starch solution. The addition of the SB-latex was determined based on the viscosity of the new adhesive. The adhesive strength and the drying energy reduction of a corrugated board were measured to evaluate the functionalities of the new adhesive. The addition of SB-latex was determined to be under 20% of the oven-dried starch based on the viscosity of the new adhesive. The adhesive strength was improved and the drying energy was reduced by applying the new adhesive.

• Resources Recycling
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• v.22 no.1
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• pp.20-28
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• 2013

Recently, as the registration of vehicles increases, the utilization of the waste tires is emerging as environmental issues. Crumb rubber reproduced by scrap tires has been reused up to 25% in the construction field. The purpose of this paper is to investigate the mechanical properties of sulfur-rubber concrete (SRC) and to suggest the optimum mix design in terms of the compressive strength. Specimens were prepared with various mixing parameters: amount of sulfur, rubber, and micro-fillers. Two casting processes were also mentioned; dry process and wet process. The results mainly showed that the compressive strength of SRC decreased with an increment of rubber content. However, adding micro-filler and adjusting sulfur contents could improve the compressive strength of SRC. Optimum values of sulfur and rubber content were selected by workability and compressive strength of SRC. SRC can be applied to road constructions where high strength of concrete is not concerned, to wall panels that require low unit weight, to construction of median in highways to resist high impact load, and in sound barriers to absorb sound waves.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.2
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• pp.58-66
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• 2012

Brewers grain is a byproduct of beer brewing and consists primarily of grain husks, pericarp, and fragments of endosperm. Although this material is consumed by animals and used as fertilizer, a large amount of brewers grain is simply discarded. Therefore, new methods for utilizing this fibrous resource should be pursued. In this study, we examined the potential utilization of brewers grain as an additive in the paperboard industry by determining the chemical composition of brewers grain and the physical properties of brewers grain powders after grinding with two types of grinders. We found that brewers grain had a lower holocellulose content and higher lignin content and intermediate ash content when compared to other biomass materials, and did not contain any contaminants that would interfere with the papermaking process. Particles had a higher fiber length, less fiber width, and narrower shape factor distribution when ground by a blender type grinder than by a pin crusher type grinder. The blender type grinder was concluded to make regular brewers grain particles appropriate for papermaking.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.20-23
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• 2012

본 연구는 유기성폐기물을 처리하고 그것을 이용하여 고체연료 또는 퇴비를 생산하는 종합시스템에 관한 것이다. 유기성폐기물은 90% 전후의 높은 함수율을 나타내고 있기 때문에 처리에 중점을 두어야 할 부분이 수분 처리 방법이다. 따라서 기존의 처리방법으로는 고액분리하여 처리 후 하천에 방류하는 시스템에 의해 처리되고 있다. 하지만 본 연구에서는 기술개발의 차별화 및 선행기술의 회피 전략을 위해, 유기성폐기물의 수분을 건조시키는 방법으로 미생물이 유기성폐기물의 유기물을 분해하여 발생 되는 $80^{\circ}C$ 이상의 열에너지에 의해 수분을 제거하는 발열반응을 적용하여 수분을 제거하는 무방류시스 템이다. 뿐만 아니라 고체연료의 발열량을 높이기 위해서 무연탄, 코크스, 기름 등의 열량보조제를 첨 가하는 대신에 유기성폐기물을 첨가 한 후 적당한 발열반응 및 건조시켜 고체연료를 제조하는 방법으 로 4,000kcal/kg 이상의 높은 발열량을 얻을 수 있으며 불완전연소 등에 의한 2차 오염을 방지할 수 있는 기술이다. 따라서 친환경 미생물 발열반응에 의해 유기성폐기물을 저렴한 비용으로 액상 및 고상 을 동시에 처리 할 수 있으며, 고체연료를 제조할 수 있는 새로운 신기술이다.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.561-569
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• 2016

Concrete is cheap, easy to deal with, and the quality is satisfactory. Also, it is one of the easiest materials to get because chemical composition of cement is similar to chemical composition of surface. On the other hand, it is so vulnerable to transform because of weak binding capacity and low binding energy that it produces cracks. Cracks decline durability, usability, safety of structures and damage exterior. In order to decline drying shrinkage crack, this study used shrinkage reducing typed Superplasticizer, which is combination of and water-reducing agent for convenience, different with existing study using AE agent, water-reducing agent, shrinkage reducing agent,. Considering SRS field application possibility, this study planned to mix concrete and mortar generally used in ready-mixed concrete company and did basic experiment depending on a change of SRS content ratio and admixture. Based on the experiment result. It is judged that SRS admixture 2% is proper ratio when Given the intensity and length change. Also mass combination will conduct follow-up studies.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.2
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• pp.33-40
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• 2013

Powdered additive or organic filler is used to improve paperboard thickness and to reduce drying energy consumption in the Korean paperboard industry. In a previous study, we identified alternative non-lignocellulosic resources to wood powder, specifically brewers grain and oil palm frond powders, and verified that these materials had the same functionality as wood powder. The main drawback of the use of such additives, including both lignocellulosic and non-lignocellulosic resources, is the deterioration in paperboard strengths. Therefore, we carried out a basic study on the surface modification of brewers grain and oil palm frond powders to improve the strengths of paperboard. Surface modification was performed using various types of cationic and oxidized starches. The streaming current and zeta-potential of the two non-lignocellulosic powders were measured and CLSM images were taken to assess the surface modification.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.114-114
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• 2018

탄소 재료는 뛰어난 물성에서 다양한 재료로의 응용이 기대되고 있다. 특히, 이종 원소 함유 카본 재료는 전기적 특성과 촉매성의 발현 등 새로운 기능을 카본 재료에 부여할 수 있어서 연료 전지, 에너지 저장, 태양 전지 등에의 응용이 기대되고 있다. 최근, 용액 중의 저온 플라즈마인 솔루션 플라즈마(solution plasma process)를 이용하여 벤젠 용액 등에서 탄소 재료 합성에 성공하였다. 그러나 기존의 연구에서는 솔루션 플라즈마 프로세스를 이용하여 합성한 이종원소 카본은 전도성이 낮아 이종원소의 함유량을 낮추는 고온의 열처리가 필요했다. 따라서 본 연구에서는 우수한 물리적 전기적 특성을 갖는 그래핀(graphene)과 같은 이종 원소 카본 나노시트(heteroatom carbon nanosheets)의 합성 및 메커니즘(mechanism)에 대해 검토하였다. 다양한 이종원소를 포함한 유기용매 안에 바이폴라 펄스 전원에 의한 전압을 두 텅스텐 전극 간에 인가하고, 솔루션 플라즈마를 생성하여 이종원소 카본 재료를 합성했다. 플라즈마 생성은 텅스텐 봉을 전극으로 사용하고 전압을 2.0 kV, 펄스 주파수를 200 kHz, 펄스 폭을 $1.0{\mu}s$, 전극 간 거리를 1.5 mm에서 일정하게 유지하며 200 mL 유기용매 중에서 방전시키는 것으로 재료를 합성했다. 플라즈마 방전 후, 필터을 이용하여 흡인 여과한 뒤 $200^{\circ}C$에서 1 시간 동안 건조 시켰다. 건조 후의 이종원소 카본의 물리적 특성을 원소 분석, X선 회절 법(XRD), 저항률 측정, 투과형 전자 현미경(TEM) 및 라만 분광법, 전자 현미경(SEM), X-선광전자분광기(XPS)등을 이용하여 카본의 형상 및 특성을 분석하였다. 그 결과 다양한 이종원소를 포함한 유기용매 중 2-pyrrolidone을 사용했을 때, 이종 원소 카본 나노시트를 합성하는데 성공하였다. 또한, 이 연구방법을 통해서 솔루션 플라즈마 프로세스를 통한 카본 나노시트 합성의 메커니즘을 규명하였다.