• Resources Recycling
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• v.24 no.6
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• pp.61-68
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• 2015

In this study, the strength properties of NHL based mortar with blending basalt fiber were investigated. In the first step, it was evaluated that physical properties of NHL based mortar according to mixing method of four types of basalt fiber and then mixing method of one type was selected. As a result of assessment, it showed that the physical properties with mixing method of dry blending were better than that of wet blending and mixing method that basalt fiber pre-mixed with NHL for 5 min in a blender was selected and water and aggregate were finally added. Secondly, the investigation of blending fiber length on the compressive and flexural strength for basalt fiber reinforced NHL based mortars was carried out. The compressive strength was decreased with adding fiber, and the flexural strength was increased more than plain mortar. In the case of adding 6 mm fiber, the compressive and flexural strength were improved more than that of others.

• Journal of the Korean Magnetics Society
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• v.5 no.6
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• pp.928-936
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• 1995

In this research, the processing control of NiCuZn Ferrite has been developed. The mixing and the size reduction of raw materials have been proceeded. In order to produce NiCuZn Ferrite, highly concentrated slurry with fixed ratio and wet ball milling were used. First, the dispersion behavior of raw mixture at the region of pH4~pH11 has been studied. Using wet ball milling operation, the best conditions of mixing and size reduction have been determined. Further more, the most suitable conditions, such as, dispersant kind, dispersant amount, milling time, and slurry concentration have been studied. The poly acrylic ammonium salt (PAN) was chosen as a suitable dispersant to have effective dispersion in basic region. The slurry of raw mixture without dispersant, showed high viscosity and poor grindability. As 0.7 wt% of PAN was added, the concentrated slurry (up to 55 vol%) was possible, and showed well grindability. After 18 h ball milling of 30 vol% of mixture slurry with 0.7 wt% of PAN, the average particle size and specific surface area of raw mixture were $0.54\mu\textrm{m}$ and $12.92m^{2}/cc$, respectively. The ball milled raw mixture, calcined at $700^{\circ}C$ for 3h, was totally changed into NiCuZn Ferrite with spinel phase.

• Korean Journal of Materials Research
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• v.14 no.9
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• pp.659-663
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• 2004

Magnetite was prepared by wet method and oil-based magnetic fluid also was prepared by its magnetite. Ahead of making magnetite, we investigated the variation of physical properties for changing $Fe^{3+}/Fe^{2+}$. Through the variation of the process mixing time, pH, magnetite content, we made magnetic fluid of magnetite. We examined the magnetic and frequency property by a toroidal mold. In result $Fe^{3+}/Fe^{2+}=1.2$, over the minute mixing time property of magnetite, Ms was 61.98 emu/g. Moreover, the B-H loop result indicated that the magnetic fluid followed paramagnetic behavior.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.3
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• pp.45-51
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• 1986

The simple and precise model for the estimation of rain acidity from the ambient air quality was developed using the theory of wet scrubber and the chemical equilibria of $SO_2, CO_2, and H_2O$ system. From the measured mixing height, and from the developed relationship between NTU (=number of transfer units) and the concentration of $SO_2$(aq) in rain drops, the HTU (= height equivalent to one transfer unit, i.e. mass transfer resistance) was estimated, and validated with the field-measured data. In Seoul, Korea where the effect of $SO_2$ on rainfall acidity is as high as 84% and the average mixing height is 1 km, the average HTU of $SO_2$ system was found to be 191.5m. The important parameters affecting HTU were identified as rainfall intensity and initial ambient concentration of $SO_2$, and their effects on the value of overall volumetric mass transfer coefficient were quantified.

• Fibers and Polymers
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• v.5 no.3
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• pp.187-197
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• 2004

The compressive and flexural properties of hemp fiber reinforced concretes (FRC) were examined in this paper. Natural hemp fiber was mixed using dry and wet mixing methods to fabricate the FRC. Mechanical properties of the FRC were investigated. The main factors affecting compressive and flexural properties of the FRC materials were evaluated with an orthogonal test design. Fiber content by weight has the largest effect. The method for casting hemp FRC has been optimised. Under the optimum conditions, compressive strength increased by 4 %, flexural strength increased by 9 %, flexural toughness increased by 144 %, and flexural toughness index increased by 214 %.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.35-46
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• 1993

This paper was concerned with the risk assessment about oxidizing substances as dangerous goods by burning test method. The sample. which was formed with the heaped cone-shape. was composed of solid oxidant and sawdust. The burning time of each sample was measured under the following various conditions circumstance temperature. mixing ratio of oxidizing substance and sawdust. particle size of sawdust and kinds of sawdust. As a results. the effective combustibility was gained when the sawdust content was 20∼30 wt.% in the sample and the lauan with -30+50 mesh was used. But. although the circumstance temperature increased. burning efficiency of the samples wet$.$e not affect by it. Finally. the average burning times were obtained by considering the weighting factors related on the mixing ratio and the circumstance temperature. And then. it were compared with the combustion risk level and the effects of cation and anion of oxidizing substances as dangerous goods.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.3
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• pp.145-149
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• 1991

A one dimensiional cumulus cloud model has been developed for the investigation of temporal and altitudinal variation of trace gases and the wet deposition rates of sulfate for different simulation conditions. The results show that the dynamic field, liquid mixing ratios and the solubility of trace gases affect the distribution of trace gases and the droplet pH. Temporal variation of the predicted surface precipitation and sulfate deposition rates agree well with the field data.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.685-688
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• 2001

We prepared D,L-phenylalanine imprinted membrane by a wet phase method. Template was imprinted in the step of copolymerization or implanted by mixing template and DMSO solution containing copolymer. The adsorption selectivity of each membrane was investigated.

• Journal of Environmental Science International
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• v.1 no.2
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• pp.15-23
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• 1992

Development of cumulus is studied by numerically integrating the equation of motion equations of conservation for water vapor mixing ratio, and the thermodynamic energy equuation. We use the terrain-following coordinate system called z'-coordinate system, in which we can easily treat any calculation domain with terrain configuration such as mountains. The model domain of calculation is restricted vertically to 4.Skin and horizontally to 100 km, has a bell-type mountain in the centeral part. Four cases are considered, one in a neutral environment, second in a slightly stable environment, third in a environment decreasing water content with low value of initial water vapor mixing ratio, the fourth in a case with higher vapor gradient. The more the atmosphere is unstable, the more cumulus develops easily and the more water vapors is abundant, the more cumulus develops easily too. More detailed cloud microphysics parameterizations and wet deposition must be conridered to use in air pollutants prediction model.

• Journal of Powder Materials
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• v.27 no.6
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• pp.468-476
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• 2020

The bone cement used for vertebroplasty must be sufficiently injectable. The introduction of granules reduces the amount of liquid required for liquefaction, implying that higher fluidity is achieved with the same amount of liquid. By employing β-tricalcium phosphate granules with an average diameter of 50 ㎛, changes in injectability are observed based on the paste preparation route and granular fraction. To obtain acceptable injectability, phase separation must be suppressed during injection, and sufficient capillary pressure to combine powder and liquid must work evenly throughout the paste. To achieve this, the granules should be evenly distributed. Reduced injection rates are observed for dry mixing and excessive granular content, owing to phase separation. All these correspond to conditions under which the clustered granules weakened the capillary pressure. The injected ratio of the paste formed by wet mixing displayed an inverted U-type shift with the granular fraction. The mixture of granules and powder resulted in an increase in the solid volume fraction, and a decrease in the liquid limit. This resulted in the enhancement of the liquidity, owing to the added liquid. It is inferred that the addition of granules improves the injectability, provided that the capillary pressure in the paste is maintained.