• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2002년도 학술발표회 발표논문집
• /
• pp.149-152
• /
• 2002

This study is performed to evaluate the properties of ECO-permeable polymer concrete with blast furnace slag powder and stone dust. The unit weight is in the range of $1,821kg/m^3{\sim}1,955kg/m^3$, the unit weights of those concrete are decreased $15%{\sim}20.8%$ than that of the normal cement concrete. The highest strength is achieved by ECO-permeable polymer concrete filled blast furnace slag powder 50% and stone dust 50%, it is increased 36% by compressive strength, 119% by tensile strength and 217% by bending strength than that of the normal cement concrete, respectively. The coefficient of permeability is in the range of $5.6{\times}10^{-2}cm/s{\sim}8.1{\times}10^{-2}cm/s$, and it is largely dependent upon the mix design.

• 한국토양비료학회지
• /
• 제46권6호
• /
• pp.556-562
• /
• 2013

The blueberry eco-friendly farming requires the soil condition of pH 4.2 ~ 5.2 and high in organic matters for stable growth. Most of soil types of blueberry-growing land in Korea, however, belongs to alkaline soils with low organic matter content. As a result, the eco-friendly blueberry growers use peat moss and sulfur powder heavily to improve the soil condition, but the guideline on the effective use of organic materials was not established yet. Therefore, this sturdy was performed to investigate the effect of increasing soil acidity and organic matters by using organic materials. Among 5 organic materials, the pH of soil was lowest in degradable sulfur + bentonite (pH 4.1) and followed by Peat moss+Chaff+Pine Needlesmixtures(pH 4.5), OrganicAcid +vinegar (pH 4.7), Sulfur powder (pH 4.8), Temperature response Elutioner (pH 5.2). The soil organic matter content were increased in the following order: Peat moss+Chaff+Pine Needlesmixtures (8.4%) > degradable sulfur + bentonite (7.8%) > Organic Acid + vinegar (7.2%) > Sulfur powder ${\fallingdotseq}$ Temperature response Elutioner (6.3%). Although different in the degree, all organic materials treated was recognized a good material for improving soil pH and organic matter content. The plant height and stem diameter of blueberry were no clear difference among 5 organic materials. Another study was carried out to investigate amending soils with organic matter by soil mulching with pine needles for soil surface management in blueberry organic cultivation. The effect of increasing the soil pH by pine needle mulching in blueberry eco-friendly farming was recognized in four test fields. Pine needle mulching for soil surface management in blueberry appeared several advantages, such as improving of soil pH and organic matter content. Therefore, pineneedle mulching in blueberry organic farming is considered as the most efficient means of mulching cultivation for amending soil pH, weed suppression and moisture conservation among mulching materials.

• 한국세라믹학회지
• /
• 제55권2호
• /
• pp.153-159
• /
• 2018

Porous ceramic plates were prepared from Onggi clay and bamboo charcoal powder at 1100 and $1200^{\circ}C$ and their porous properties and water absorption, and the cooling effect of porous plates, were investigated to produce eco-friendly porous ceramics for a self-cooling system that relies on the evaporation of absorbed water. Porous properties were dependent on the particle size of charcoal powder pore forming additive and the firing temperature; properties were also found to be dependent on the total pore volume, average pore size and porosity, which had values of $0.103-0.243cm^3/g$, 0.81 - 2.56 mm and 20.9 - 38.2%, respectively, at $1100^{\circ}C$ and $0.04-0.18cm^3/g$, 0.33 - 2.03 mm and 10.8 - 30.9%, respectively, at $1200^{\circ}C$. Cooling temperature difference of flowing air parallel to surface of porous ceramic plates fired with two kinds of charcoal powder at $1100^{\circ}C$ was $3.5-3.6^{\circ}C$ at $26^{\circ}C$ and 60% of relative humidity in a closed box. Cooling temperature difference was dependent on the number of porous plates and the distance between porous plates. A simple and eco-friendly cooling system using porous ceramic plates fired from Onggi clay and charcoal powder was proposed.

• 한국자원식물학회지
• /
• 제19권6호
• /
• pp.721-726
• /
• 2006

Mosquitoes are carriers of malaria and encephalitis. This study performed for eco-friendly control of mosquitos by using genus Acorus. Several solvents were used for the extraction of genus Acorus; water, ethanol, and methanol. Grinded leaves and roots were also included. Acorus extracts killed mosquito larvae and the ethanol extract showed the best result. Autoclaved Acorus water needed long time to kill mosquito larvae. $LT_{50}$ of 1 % Acorus calamus decoction was 13.6 hrs and 1 % autoclaved Acorus water was 53.6 hrs. $LT_{50}$ of 0.05% Acorus calamus rhizome powder was 28.5 hrs. $LT_{50}$ of 0.5% Acorus calamus leaf powder was 10.8 hrs. $LT_{50}$ of 0.1 % Acorus calamus decoction was 63.4 hrs and 0.1 % Acorus calamus ethanol extracts was 48.6 hrs and 0.1% Acorus calamus methanol extracts was 53.9 hrs. $LT_{50}$ of 0.4% Acorus gramineus decoction was 45.5 hrs, 0.4% ethanol extracts was 10.9 hrs, 0.4% methanol extracts was 10.2 hrs. $LT_{50}$ of ethanol extracts was shorter than other extracts. Acorus calamus rhizome powder could be used for the eco-friendly control of the mosquito larvae.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.957-958
• /
• 2006

Fe doped skutterudite $CoSb_3$ with a nominal composition of $Fe_xCo_{1-x}Sb_{12}(0{\leq}x{\leq}2.5)$ have been synthesized by mechanical alloying (MA) of elemental powders, followed by vacuum hot pressing. Phase transformations during mechanical alloying and vacuum hot pressing were systematically investigated using XRD. Single phase skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. However, second phase of $FeSb_2$ was found to exist in case of $x\geq2$, suggesting the solubility limit of Fe with Co in this system. Thermoelectric properties as functions of temperature and Fe contents were evaluated for the hot pressed specimens. Fe doping up to x=1.5 with Co in $Fe_xCo_{4-x}Sb_{12}$ appeared to increase thermoelectric figure of merit (ZT) and the maximum ZT was found to be 0.78 at 525K in this study.

• 한국세라믹학회지
• /
• 제42권10호
• /
• pp.678-684
• /
• 2005

Sick house syndrome comes from VOCs that is harmful to health. To reduce VOCs, the cause of sick house syndrome, several materials have been developed and use. One of this materials, VOCs absorption paint was developed. VOCs absorption paint contains ceramic binder and zeolite powder. In the present study, eco-ceramics paint has been successfully fabricated by high-speed mixer using ceramic binder and filler powders. The eco-ceramics paint thus obtained have a deodorization rate with about 95.7$ \%$ and the bacteria decreasing rate is about 99.6$\%$. Moreover, the eco-ceramics paint showed excellent VOCs interception properties due to effect of ceramics layer and zeolite which exist in surface of paint.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
• /
• pp.688-689
• /
• 2006

Ni-doped $CoSb_3$ was prepared by the encapsulated induction melting and hot pressing, and its doping effects on the thermoelectric properties were investigated. Single phase $\delta-CoSb_3$ was successfully obtained by the subsequent heat treatment at 773K for 24 hours. Nickel atoms acted as electron donors by substituting cobalt atoms. Thermoelectric properties were remarkably improved by the appropriate doping.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.1254-1255
• /
• 2006

For precise property control of sintered products, it is important to understand accurately the packing density of the powder. We developed a packing simulation program that could make a packed bed of spherical particles having particle size distribution. In addition, the influence of the particle shape of the actual powder on the packing density was quantitatively analyzed. The predicted packing densities corresponded well to the actual data.

• 대한금속재료학회지
• /
• 제49권11호
• /
• pp.853-859
• /
• 2011

Compressive deformation behavior of Al-10Si-5Fe-1Zr (wt%) alloy preform fabricated by SPS(spark plasma sintering) of gas atomized powder was investigated in the temperature range from 380 to $480^{\circ}C$ and at strain rates from $1.0{\times}10^{-3}$ to $1.0{\times}10^{0}s^{-1}$. Stress-strain curves showed a peak stress (${\sigma}_p$) during initial stage of deformation, followed by a steady state flow at all temperatures and strain rates tested. The (${\sigma}_p$) decreased with both increase in temperature and decrease in strain rate. Nearly full densification was found to occur in the compressively deformed specimens irrespective of test condition. TEM observation revealed a restricted grain growth during steady state flow.

• 한국재료학회지
• /
• 제23권10호
• /
• pp.592-598
• /
• 2013

Graphene oxide powders prepared by two different drying processes, freeze drying and spray drying, were studied to compare the effect of the drying method on the physical properties of graphene oxide powder. The graphene oxide dispersion was prepared from graphite by chemical delamination with the aid of sulfuric acid and permanganic acid, and the dispersion was further washed and re-dispersed in a mixed solvent of water and isopropyl alcohol. A freeze drying method can feasibly minimize damage to the sample, but it requires a long process time. In contrast, spray drying is able to remove a solvent in a relatively short time, though this process requires exposure to a high temperature for a rapid evaporation of the solvent. The powders prepared by freeze drying and spray drying were characterized and compared by Raman spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and by an elemental analysis. The graphene oxide powders showed similar chemical compositions; however, the morphologies of the powders differed in that the graphene oxide prepared by spray drying had a winkled morphology and a higher apparent density compared to the powder prepared by freeze drying. The graphene oxide powders were reduced at $900^{\circ}C$ in an atmosphere of $N_2$. The effect of the drying process on the properties of the reduced graphene oxide was examined by SEM, TEM and Raman spectroscopy.