• 한국안전학회지
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• 제12권3호
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• pp.90-96
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• 1997

This paper was concerned with temperature aspect in the smoldering time of the accumulated each saw-dust sample of larch, oregon, aromatic trees which was formed with heaped cone-shape. The smoldering time and temperature of each sample was measured under the wind velocity of 0.10~0.15 m/s and circumstance relative humidity of 60%. As a result, the very lowest heat beginning temperature was detected in aromatic. The effective smoldering phenomena in the sample were detected when the larch saw-dust of [-20+40mesh] and the aromatic saw-dust of [-40+50mesh, -50+60mesh]. Finally the larger a particle size of saw-dust was the better a smoldering time was short. Also, it showed more increasing temperature above $70^{\circ}C$in the smoldering reaction.

• 한국안전학회지
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• 제20권2호
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• pp.98-104
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• 2005

Saw dust concrete f3r finding out insulation characteristic was tested using test plate $30cm{\times}30cm{\times}5cm$. basically, molds f3r the test of compressive, tensile, normal without sawdust, $0.05\%,\;0.1\%,\;0.2\%,\; 0.4\%,\;0.6\%,\;0.8\%,\;1.0\%,\;1.2\%,\;1.4\%,\;1.6\%,\;1.5\%,\;2.0\%$, mixing proportion. heat conductivity of the saw dust concrete mixed with the above proportion was taken in this study. Thermal conduction of normal concrete depends on mixing proportion strength aggregate character, water content. all these items are specified here in fables. $1.8\%\~2.0\%$ saw-dust mising concrete shows as the faction as normal insulation material has its function. and the higher saw-dust mixing rate becomes, the thermal conduction becomes the less Then, the conclusions are that saw-dust using concrete has better insulation function than normal concrete.

• 한국세라믹학회지
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• 제20권2호
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• pp.135-146
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• 1983

This study is to investigate the properties of domestic fly ash for utilization as data in regard to fly ash which is by-product of domestic coal powder plants and the possibility of utilization as insulation material of domestic fly ash. Composition refractoriness size distribution density contents of hollow particles and crystalline phase were examined as the properties of domestic fly ash. As to the fired test pieces of fly ash by itself that varied contents of hollow particles with four kinds and of the fly ash-clay-saw dust system linear shrinkage bulk density app. porosity compressive strength thermal conductivity and structures were investigated for the possibility of utilization as an insulation material. The results are as follows : 1. The properties of the fly ash I) The constituent particle of the fly ash is spherical and it contains not a few hollow particles (floats by water 0.30-0.50 floats by $ZnCl_2$ aq.(SpG=1.71) 6.97-16.72%). ii) The chemical compositions of fly ash are $SiO_243.9-54.1%$ , $Al_2O_321.0-30.7%$ Ig loss is 7.4-24.1% and the principal of Ig loss is unburned carbon. iii) Fly ash was not suitable to use for mortar and concrete mixture because Ig. loss value is higher than 5% 2. Utilization as insulation material I) The test pieces of original fly ash floats by water floats by ZnCl2 aq(SpG=1.71) p, p t by ZnCl2 aq.(SpG=1.71) that were fired at 110$0^{\circ}C$ represented 0.11-0.18 kcal/mh$^{\circ}$ C as thermal conductivity value. ii) The test pieces which (76.5-85.5) wt% fly ash-(8.5, 9.5) wt% clay-(5.0-15.0) wt% saw dust system(68.0-72.0) wt% fly ash -(17.0-18.0)wt% clay-(10.0-15.0) wt% saw dust system and 59.5 wt% fly ash-25.5 wt% clay-15.0wt% saw dust system were fired at 110$0^{\circ}C$ the thermal conductivity was less than 0.1Kcal/mh$^{\circ}$ C. iii) In view of thermal conductivity and economic aspect insulation materials which added saw dust as blowing agent and clay as inorganic binder are better than that of fly ash as it is or separated hollow fly ash particles. iv) When the saw dust contents increased in the (59.5-90.0) wt% saw dust system and when amount of clay de-creased and firing temperature decreased under the condition of equal addition of saw dust app. porosity increased but bulk density compressive strength and thermal conductivity decreased.

• Environmental Engineering Research
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• 제22권3호
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• pp.320-328
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• 2017

This paper describes the non-isothermal pyrolysis of wood pellet and saw dust, and their blends with bituminous coal. The blends showed the distinct, two peaks in thermogravimetric curves, and the first peak came from the biomass pyrolysis and the second one came from the coal pyrolysis. The interaction in the blend was evaluated in terms of the maximum rate of weight loss, characteristic temperatures, char yields, and the calculated and experimental thermogravimetric curves. The activation energies and frequency factors for the blends were obtained with the multi-stage, Coats and Redfern method. The respective activation energies of 73 and 67 kJ/mol and the frequency factors of 725,100 and $65,262min^{-1}$ were obtained for the present wood pellet and saw dust samples. The thermogravimetric study shows that there is no significant interaction between the present biomass and coal in the blends, and the pyrolysis behavior can be described with the additive rule.

• 한국균학회지
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• 제3권2호
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• pp.25-29
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• 1975

우리나라 담자균류 12균주 중 톱밥의 lignin을 잘 분해하는 균주 Pleurotus ostreatus 1주를 선발할 수 있었다. 이 균주는 톱밥에 20%의 미강을 첨가하고 보통배지에 첨가되는 무기염을 첨가하면 $30^{\circ}C$에서 30일이면 lignin의 49%를 분해할 수 있었고 다시 무기 N을 단백질로 전환시킬 수도 있으며 여기서 단백질 증가율은 26%였다.

• 한국안전학회지
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• 제20권3호
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• pp.126-133
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• 2005

Behavior of saw-dust concrete has not studied because many people have thought that saw-dust concrete cannot be applicable for structural member, up to now. This study is to findout how much the concrete can be structurally applicated. 5mm grid sieve was used to select satisfactory sawdust for better concrete quality. Test molds size of ${\phi}10{\times}20cm$ long were made of normal without sawdust, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8% 2.0%, for making concrete strengh of 180kg, 210kg, 240kg, 270kg which they are normally used in practice presently. A various strengths tests such as compressive splitting tensile, flexible strength behavior of structural member named beam using size of $20{\times}30{\times}120cm$ have been done for the structural aspects. Tensile strength shows that it can be more affected than higher strength of it.

• 유기물자원화
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• 제8권4호
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• pp.100-110
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• 2000

음식찌꺼기의 사료화를 위한 발효처리시 수분조절제로 이용되는 재료 (톱밥, 버섯폐재, 밀기울, 야자박 등)와 발효방법 (호기성파 혐기성)및 발효기간이 음식찌꺼기 사료의 사료가치에 미치는 영향을 구명하기 위한 일련의 시험을 실시하였다. 본 연구의 시험설계는 농가 지도자료로 활용 될 수 있도록 하였다. 참나무 톱밥과 소나무 톱밥의 NDF(중성세제 불용성 섬유)함량은 각각 건물기준 93.5%와 95.4%로써 사료로 이용하기는 어려운 재료라고 할 수 있다. 톱밥을 수분조절제로 50% 혼합하여 $30^{\circ}C$에서 2일간 호기성발효를 했을때 NDF 함량은 발효 전 재료에 비하여 12% 증가했고 in vitro DDM (인공반추위 건물소화율)은 48% 감소했다. 참나무 톱밥은 소나무 톱밥에 비하여 양호하였으며, 버드나무 톱밥(80%)과 밀기울(20%)을 혼합하여 팽이버섯재배의 배지로 이용된 후의 폐재는 톱밥류에 비하여 사료가치가 우수한 것으로 나타났다. 발효된 사료의 NDF함량과 건물소화율은 이용된 수분조절제의 NDF함량에 주로 관계된다는 것을 알 수 있었다. 버섯폐재를 밀기울로 대체 했을때 밀기울의 대체율이 증가함에 따라 발효된 사료의 NDF함량은 직선적으로 감소했고 소화율은 직선적으로 증가했다. NDF함량이 높은 수분조절제를 이용한 호기성발효는 발효기간이 길어질수록 NDF함량은 증가되었고 건물소화율은 감소되었다. 그러나 밀기울 만을 이용하거나 밀기울이 함유된 수분조절제는 발효기간이 연장됨에 따라 조단백질 함량이 증가되었다. 혐기성발효는 호기성 발효에 비해 전 처리구에서 NDF함량은 감소되었고 건물소화율은 향상되었다. 버섯폐재와 밀기울을 수분조절제로 이용하여 실온에서 30일간 혐기적으로 발효한 사료를 유기산 조성과 pH가를 기준으로 발효상태를 판정할 때 우수한 것으로 나타났다.

• 한국산업보건학회지
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• 제20권4호
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• pp.274-281
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• 2010

The objectives of this study are (a) to investigate the distribution patterns and exposure concentrations of biological agents in sawmill industries and (b) to compare sampling methods of biological agents. The representative processes of 5 sawmills were selected to measure total airborne bacteria, fungi, endotoxin as well as dust. Airborne bacteria and fungi were measured with one stage impactor, six stage impactor and gelatin filteration methods. Endotoxin was collected with polycarbonate filters and analysed by kinetic chromogenic Limulus Amebocyte Lysate method. Geometric mean levels of airborne bacteria, fungi, endotoxin and dust were 1,864 CFU/$m^3$, 2,252 CFU/$m^3$, 31.5 EU/$m^3$ and 2.4 mg/$m^3$. The ratios of indoor/outdoor concentrations were 3.7 for bacteria, 4.1 for fungi, 3.3 for endotoxin and 9.7 for dust. The respiratory fractions of bacteria were 68.0, 50.9, 49.2 and 45.1% in band-saw, table-saw, rip-saw process and outdoor air. The respiratory fractions of fungi were 78.7, 90.8, 87.5 and 84.8% in band-saw, table-saw, rip-saw process and outdoor air, respectively. There was no significant differences in bacterial concentrations among single stage, six stage impaction and filteration methods. But, fungal concentrations measured with filtration methods were significantly higher than those with impaction methods. Geometric mean levels of airborne bacteria and fungi were higher than the OSHA guideline values of 1,000 CFU/$m^3$. The respiratory fractions of fungi were above 75%. The concentrations of biological agents were significantly different among culture-based sampling methods. In the exposure assessments of biological agents, further studies are needed for the comparisons of diverse sampling methods and the investigations of environmental factors.

• 한국기계가공학회지
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• 제17권6호
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• pp.83-90
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• 2018

This paper introduces a innovative diamond wire saw cutting technology and its experimental verification that can be utilized for cutting heavy structures. While conventional diamond wire saw cutting technologies such as water cooled cutting method and dry cutting method cause severe environmental problems due to generating massive concrete sludge or dust scattering, the proposed method can eliminate those problems considerably. Through extensive experiments using heavy structure test bed and real bridge pier structure, comprehensive analysis and comparative evaluation about various cutting methods were performed. As a result, the innovative diamond wire saw cutting method could achieve a similar cutting and cooling performance to the water cooled cutting method without generating concrete sludge and it showed an improved cutting and cooling performance to the dry cutting method without dust scattering. Consequently it is confirmed that the suggested cutting technology can be a promising environment-friendly alternative in the field of heavy structure dismantling.

• 한국토양비료학회지
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• 제49권6호
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• pp.760-767
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• 2016

Food waste (FW) has been recognized as a critical problem in Korea and many research was conducted to efficiently utilize or treat FW. Main purpose of this research was to evaluate a feasibility for producing fermented organic fertilizer with vegetable waste (VW). Three different organic materials (saw dust, coco peat, and waste mushroom media) were mixed with VW at the rate of 30, 40, 50% respectively. Total days of composting experiment were 35 days and each sub samples were collected at every 5 days from starting of composting. Result showed that inner temperature of composting was increased to $60{\pm}4^{\circ}C$ within 5~10 days depending on varied organic materials and mixing ratio. Among different treatment, the highest increase of inner temperature was observed when 30% of saw dust was mixed with VW. After finishing composting experiment, maturity of each compost was evaluated with solvita and germination test. Maturity index (MI) of each treatment was ranged between 5~7 indicating that manufactured fertilizer was curing or finished stage. Calculated germination index (GI) was at the range of 57.83~101.16 depending on organic materials and mixing ratio. Both MI and GI showed that manufactured fertilizer was met for fertilizer criteria while control (VW only) was not adequate for composting. Overall, VW can be utilized for making organic fertilizer mixing with saw dust, coco peat and more research should be conducted to make high quality of organic fertilizer with vegetable waste.