• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1121-1121
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• 2006

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.130-133
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• 2006

This study was conducted to select Codonopsis lanceolata seed's new pelleting particulate materials and adhesives. Different adhesives (Polyvinyl alcohol (PVA), Carboxymethyl cellulose (CMC), Polyvinyl pyrrolidone (PVP), Xanthan gum (XG), Arabic gum (AG)) and particulate materials (Illite, Diatomite, Pyrophyllite + Illite + Diatomite (PID), Pyrophyllite + Illite + Talc (PIT), Bentonite + Talc (BT)) were tested for seed pelleting. PID for Codonopsis lanceolata seed pelleting appeared to be the best particulate material. Among the pelleting adhesives, PVP was the best adhesive for seed pelleting, and the optimum concentration for germination of pelleting seed was 1 %. Germination rate of the pelleted seeds treated with PID particulate material and PVP adhesive was higher (86.8%) than those of raw seeds (85.5%). $T_{50}$ and MDG of pelleted Codonopsis lanceolata seed required five and eight days at soil moisture content of 50%, respectively.

• Korean Journal of Materials Research
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• v.19 no.10
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• pp.538-543
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• 2009

Active clays, Diatomite, bentonite and zeolite were used as porous materials for fabricating hygroscopic gypsum boards. Pohang active clay and Cheolwon diatomite showed excellent characteristics of moisture adsorption and desorption. These characteristics were caused by higher surface area and pore volume of porous materials. Moisture adsorption content of gypsum board with 10% active clay(P1) was 62.0 g/m$^2$, and moisture desorption content was 50.2 g/m$^2$. Moisture adsorption content of gypsum board with 10% diatomite(P) was 59.5 g/m$^2$, and moisture desorption content was 49.0 g/m$^2$. Moisture adsorption contents of gypsum boards with porous materials were higher than that moisture desorption contents of gypsum board without porous materials. Correlation coefficient between surface area and moisture adsorption content of gypsum boards was 0.98. Also, correlation coefficient between surface area and moisture desorption content of gypsum boards was 0.97. Moisture adsorption and desorption contents were influenced by surface area and pore volume of the gypsum boards, and surface area had a larger effect on moisture adsorption and desorption.

• Computers and Concrete
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• v.9 no.6
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• pp.427-437
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• 2012

This article presents the effect of replacement fly ash (FA) with diatomite (DE) on the properties of geopolymer mortars. DE was used to partially replace FA at the levels of 0, 60, 80 and 100% by weight of binder. Sodium silicate ($Na_2SiO_3$) and sodium hydroxide (NaOH) solutions were used as the liquid portion in the mixture in order to activate the geopolymerization. The NaOH concentrations of 15M, $Na_2SiO_3$/NaOH ratios of 1.5 by weight, and the alkaline liquid/binder (LB) ratios by weight of 0.40, 0.50, 0.60 and 0.70 were used. The curing at temperature of $75^{\circ}C$ for 24 h was used to accelerate the geopolymerization. The flows of all fresh geopolymer mortars were tested. The compressive strengths and the stress-strain characteristics of the mortar at the age of 7 days, and the unit weights were also tested. The results revealed that the use of DE to replace part of FA as source material in making geopolymer mortars resulted in the increased in the workability, and strain capacity of mortar specimens and in the reductions in the unit weights and compressive strengths. The strain capacity of the mortar increased from 0.0028 to 0.0150 with the increase in the DE replacement levels from 0 to 100%. The mixes with 15M NaOH, $Na_2SiO_3$/NaOH of 1.5, LB ratio of 0.50, and using $75^{\circ}C$ curing temperature showed 7 days compressive strengths 22.0-81.0 MPa which are in the range of normal to high strength mortars.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.705-708
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• 2008

Diatomite, bentonite and zeolite were used as porous materials for fabricating hygroscopic panels. Moisture adsorption and desorption of porous materials were investigated and hydrothermal method was applied to fabricate panels. Cheolwon diatomite and Pohang zeolite showed excellent characteristics of moisture adsorption and desorption. These characteristics were caused by higher surface area and pore volume of porous materials. Moisture adsorption contents were influenced by surface area and pore volume of panels, and surface area more effected on moisture adsorption. Moisture adsorption content of panel with 10% Pohang zeolite was 180g/m$^2$and that of 10% Cheolwon diatomite was 170g/m$^2$. Moisture desorption content of panel with 10% Pohang zeolite was 105g/m$^2$. Moisture adsorption contents of panel with porous materials were higher than that of panel without porous materials.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.81-95
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• 1994

This study was performed in a diatomite factory where silicosis had been found at October, 1993. The major objectives were to evaluate worker exposure to diatomaceous earth and to present engineering control methods for workplace management. Total and respirable dust of diatomaceous earth were measured. Size distribution of dust was analyzed by applying the multiple diffraction method. Also crystalline silica in respirable dust samples was analyzed qualitatively by X-ray diffraction. The suitable Local Exhaust Ventilation systems for that factory were recommended. The results were as follows. The airborne total and respirable dust concentrations by exposure groups showed approximate normal distribution. The means of total dust exposures at flour maufacturing, fire brick grinding and packaging, ceramic raws packaging processes exceeded Korean and ACGIH standards, $10mg/m^3$. The means of total and respirable dust concentrations to high exposure groups were 6.8 and 3.9 times higher than those of low expousre groups, respectively. The size distribution of diatomaceous earth dust was lognormal with a median diameter of $7.07{\mu}m$(range, $0.10-60.0{\mu}m$) and with a geometric standard deviation of 1.43. The crystalline silica in respirable dust samples was identified to quartz and cristobalite and/or tridymite. Above results suggest that engineering controls and periodic environmental and medical surveillances will be important for preventing silicosis in the diatomite factory.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.22-29
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• 2015

In this study, we tested to develop and apply structural insulation performance improvement concrete to field, which had compressive strength in 24 MPa and thermal conductivity twice as much as normal concrete. After experiment about slump and air contents, combination product of Plain and calcined diatomite powder showed reduction of slump and air contents and combination product with micro foam cell admixture, we cannot find result of slump and air contents reduction. Unit weight of combination product with insulation performance improvement materials decreased more than that of Plain. In the test of compressive strength, compressive strength of insulation performance improvement concrete decreased more than that of Plain but was content with 24 MPa. thermal conductivity of insulation performance improvement concrete tended to decrease. Freezing and thawing resistance of insulation performance improvement concrete was similar to that of Plain. In carbonation resistance test, combination product with calcined diatomite powder showed the result which was similar to that of Plain. In carbonation resistance test, combination product with micro foam cell admixture showed a increase compared to that of Plain and length variation of combination product generally increased.

• Journal of Life Science
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• v.17 no.12
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• pp.1605-1609
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• 2007

The created microbial pesticide was used to examine its effects using the inside-pot test method. The selected microbial pesticide KBC3017 particle pesticide manufactured by using Monacrosporium thaumasium was used in the farm-house outdoor test to find the optimum consistency and its effects. The more amount used, the better effect it showed. However, the optimum consistency was 2% and the KBC3017 particle pesticide for which the diatomite and raw jade powder were used as an increaser, when used 2% level of the total amount of soil, showed 71% effect on nematode prevention. The root and the stem of crops were better compared to those without any pesticide used.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.203-208
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• 2002

미생물 생산은 다양한 산업에 이용되는 핵심산업이다. 그러나 미생물을 장기간 보존하거나 생산 후 현장처리에 상황에 있어 미생물의 활성이 환경 및 각종조건에 따라 장기간 유지되지 못하는 경향이 있다. 따라서, 본 실험에서는 Pseudomonas putida SSEoX의 생산 후 시중에서 판매되는 perlite, diatomite, bentonite, zeolite, dolomite, vermicullite 등의 담체를 이용하여 미생물의 생리활성유지를 위한 실험을 자연현상에서 나타날 수 있는 다양한 온도에서 담체의 종류별로 수행하였다. 그 결과 bentonite를 이용한 담체의 경우 5, 20, 3$0^{\circ}C$에서 40일간 미생물의 밀도가 거의 감소하지 않은 결과로 나타났고 zeolite의 경우 20일 이내의 저온에서 생존율이 높은 것으로 나타났으나 온도의 상승으로 생존율이 현저히 떨어졌다. 또한 Dololite의 경우 초기 20일 내에서는 20t에서 생존율이 매우 높았으나 40일 후 생존율이 현저히 감소하였다. 또한 bentonite의 경우 전체적으로 생존율이 거의 감소되지 않았으며 그중 5$^{\circ}C$와 2$0^{\circ}C$에서 생존율이 가장 높았고 3$0^{\circ}C$에서 30일 후까지는 비교적 적은 감소를 보였으며 40일 이후 비교적 큰 감소율이 있었다. 따라서, 본 실험결과 비교적 낮은 온도에서 bentonite와 vermiculite를 혼합한 담체를 이용한 미생물보존이 가장 우수만 생존유지법이었다.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1653-1659
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• 2015

Epothilone, which is produced by the myxobacterium Sorangium cellulosum, contributes significant value in medicinal development. However, under submerged culture conditions, S. cellulosum will accumulate to form bacterial clumps, which hinder nutrient and metabolite transportation. Therefore, the production of epothilone by liquid fermentation is limited. In this study, diatomite-based porous ceramics were made from diatomite, paraffin, and poremaking agent (saw dust). Appropriate methods to modify the porous ceramics were also identified. After optimizing the preparation and modification conditions, we determined the optimal prescription to prepare high-performance porous ceramics. The structure of porous ceramics can provide a solid surface area where S. cellulosum can grow and metabolize to prevent the formation of bacterial clumps. S. cellulosum cells that do not form clumps will change their erratic metabolic behavior under submerged culture conditions. As a result, the unstable production of epothilone by this strain can be changed in the fermentation process, and the purpose of increasing epothilone production can be achieved. After 8 days of fermentation under optimized conditions, the epothilone yield reached 90.2 mg/l, which was increased four times compared with the fermentation without porous ceramics.