• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.106-112
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• 2016

This study investigated electrical properties and far-infrared ray emission according to the carbonizing temperature and phenol-formaldehyde (PF) resin impregnation ratio of ceramics manufactured using sawdust and rice husk. The far-infrared ray emission values and emission energy values decreased as the carbonizing temperature increased. The far-infrared ray emission values of the ceramics manufactured using a carbonizing process at $600^{\circ}C$ and a board with a PF resin impregnation ratio of 60 percent was 0.930; the emission energy presented the highest value of $4.32{\times}10w/m^2$. The electric resistance decreased as the carbonizing temperature increased. For the increase in the carbonizing temperature above $1200^{\circ}C$, ceramics was very close to a conductor due to the small resistance. The power consumption increased by the decrease of electric resistance and increase of the electric current in the case of a higher resin impregnation ratio.

• Carbon letters
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• v.7 no.3
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• pp.171-179
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• 2006

A carbonaceous sorbent was prepared from rice husk via sulphuric acid treatment. After preparation and washing, the wet carbon with moisture content 85% was used in its wet status in this study due to its higher reactivity towards Cr(VI) than the dry carbon. The interaction of Cr(VI) and the carbon was studied and two processes were investigated in terms of kinetics and equilibrium namely Cr(VI) removal and chromium sorption. Cr(VI) removal and chromium sorption were studied at various initial pH (1.6-7), for initial Cr(VI) concentration (100 mg/l). At equilibrium, maximum Cr(VI) removal occurred at low initial pH (1.6-2) where, Cr(III) was the only available chromium species in solution. Cr(VI) removal, at such low pH, was related to the reduction to Cr(III). Maximum chromium sorption (60.5 mg/g) occurred at initial pH 2.8 and a rise in the final pH was recorded for all initial pH studied. For the kinetic experiments, approximate equilibrium was reached in 60-100 hr. Cr(VI) removal data, at initial pH 1.6-2.4, fit well pseudo first order model but did not fit pseudo second order model. At initial pH 2.6-7, Cr(VI) removal data did not fit, anymore, pseudo first order model, but fit well pseudo second order model instead. The change in the order of Cr(VI) removal process takes place in the pH range 2.4-2.6 under the experimental conditions. Other two models were tested for the kinetics of chromium sorption with the data fitting well pseudo second order model in the whole range of pH. An increase in cation exchange capacity, sorbent acidity and base neutralization capacity was recorded for the carbon sorbent after the interaction with acidified Cr(VI) indicating the oxidation processes on the carbon surface accompanying Cr(VI) reduction.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.336-336
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• 2011

본 연구에서는 강우시 경사지 밭에서 발생하는 토양유실량을 저감하기 위하여 지표피복재의 유무와 강우강도를 달리하여 실외인공강우 실험을 통하여 평가하였다. 인공강우 실험은 경사도 28%와 각 시험포는 $5\times30m$의 크기로 strawmat+PAM+sawdust, control(bare), strawmat+PAM, strawmat+PAM+rice husks를 4개 조성하고, 각 시험포는 하단부에 강우유출수를 채취할 수 있는 설비(flume)를 설치하였다. 대조구 실험을 위하여 각 시험포에서 발생하는 직접유출량과 유사량을 비교 분석하였다. 시험포의 토양은 양질사토로 일반 고랭지 밭의 흙과 동일한 성질을 가지고 있는 토양을 사용하였고, 지표 피복처리는 straw mat, saw dust, rice husk 그리고 PAM 등 4개의 재료를 사용하였다. 인공강우 실험은 1차 10월 18일, 2차 10월 24일, 3차 10월 30일, 4차 11월 7일로 총 21일간 각각 약 1주일의 간격을 두고 실시하였으며 인공강우 시험기의 강우강도는 각 31.1 ~ 44.4 mm/hr로 모의하였다. 연구결과 시험포에서 발생한 유출량은 지표피복을 하지 않은 대조구 시험포보다 지표를 피복한 시험포에서 약 15.7 ~ 19%의 감소한 것으로 나타났다. 유사량은 대조구 시험포보다 약 93.1 ~ 99.3% 감소한 것으로 나타났으며, 유출량과 유사량은 straw mat+PAM+sawdust와 straw mat+PAM+rice husk를 적용한 시험포에서 저감효과가 큰 것으로 나타났다. 이와 같이 지표피복처리는 강우가 발생하였을 때 강우타격력의 감소와 유출수의 유속감소 그리고 침투능을 증가하는 역할을 하여 경사지, 농경지 및 공사현장에서 토양 유실을 저감하며, 하천이나 강으로 유입되는 탁수량의 저감에 큰 효과가 있을 것으로 판단된다.

• The Journal of the Korea Contents Association
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• v.15 no.3
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• pp.427-437
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• 2015

Concrete, as a construction material, needs suitable reinforcement for tensile region due to weak tensile strength. Many researches on cement reduction have been attempted for $CO_2$ emissions during cement clinker production. In this paper engineering properties of concrete enhanced with polypropylene fiber (PPF) and rice husk ash (RHA) are evaluated. Fiber volume ratios of 0.125~0.375 and RHA replacement ratio of 0~20% are considered for concrete mixture. Lots of test including compressive, split, flexural and the related crack width, impact energy, and pull out test are performed and the results are evaluated considering the fiber ratios, fiber length and RHA replacement. Fiber and RHA ratios have dominant effects on tensile and compressive characteristics respectively, and the concrete with 0.125% of PPF and 10% of RHA shows the most effective enhancement for engineering properties. Appropriate addition of RHA and PPF are very effective both for engineering property enhancement and clean technology.

• Carbon letters
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• v.15 no.1
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• pp.57-66
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• 2014

Three activated carbons (ACs) were prepared using NaOH (N) as an activating agent. Hydrofluoric acid pre-leached rice husk was used as a precursor. After leaching, the precursor was washed with distilled water, dried, crushed, and then sieved; a size fraction of 0.3-0.5 mm was selected for carbonization in the absence of air at $600^{\circ}C$. The carbonization product (LC) was mixed with NaOH at ratios of 1:2, 1:3, and 1:4 (wt of LC: wt of NaOH) and the produced ACs after activation at $800^{\circ}C$ were designated NLC21, NLC31, and NLC41, respectively. Surface and textural properties were determined using nitrogen adsorption at $-196^{\circ}C$, scanning electron microscopy images, thermogravimetric analysis, and Fourier transform infrared spectra. These ACs were used as adsorbents for lead(II) from aqueous solutions. The effects of the textural properties and the chemistry of the carbon surfaces were investigated and the impact of the operation conditions on the capacity for lead(II) sorption was also considered. Modification of NLC41 with $H_2O_2$ and $HNO_3$ gave two other adsorbents, $H_{NLC41}$ and $N_{NLC41}$ respectively. These two new samples exhibited the highest removal capacities for lead(II), i.e.117.5 and 128.2 mg/g, respectively. The adsorption data fitted the Langmuir isotherm and the kinetic adsorption followed pseudo-second order kinetics. The thermodynamic parameters have been determined and they indicated a spontaneous endothermic process.

• Advances in environmental research
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• v.1 no.1
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• pp.83-96
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• 2012

The water sludge is generated from the treatment of water with alum. Disposing of sludge again to the streams raises the concentrations of aluminum oxides in water, which has been linked to Alzheimer's disease. The use of water treatment plant (WTP) sludge in manufacturing of constructional elements achieves both the economical and environmental benefits. Due to the similar mineralogical composition of clay and WTP sludge, this study investigated the complete substitution of brick clay by sludge incorporated with some of the agricultural and industrial wastes, such as rice husk ash (RHA) and silica fume (SF). Three different series of sludge to SF to RHA proportions by weight were tried, which were (25: 50: 25%), (50: 25: 25%), and (25: 25: 50%), respectively. Each brick series was fired at 900, 1000, 1100, and $1200^{\circ}C$. The physical and mechanical properties of the produced bricks were then determined and evaluated according to Egyptian Standard Specifications (E.S.S.) and compared to control clay-brick. From the obtained results, it was concluded that by operating at the temperature commonly practiced in the brick kiln, a mixture consists of 50% of sludge, 25% of SF, and 25% of RHA was the optimum materials proportions to produce brick from water sludge incorporated with SF and RHA. The produced bricks properties were obviously superior to the 100% clay control-brick and to those available in the Egyptian market.

• Environmental Engineering Research
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• v.23 no.3
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• pp.250-257
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• 2018

We developed new composites by combining the solid waste from Low-Density Polyethylene in the form of plastic bag (PB) and biomass from rice husk (RH),in the form of $(RH)_x(PB)_{1-x}$ (x = (1, 0.9, 0.7, 0.5)), as alternative fuels for electrical energy sources, and for providing the best solution to reduce environmental pollution. Elemental compositions were obtained by using proximate analysis, ultimate analysis, and X-ray fluorescence spectroscopy, and the thermal characteristics were obtained from thermogravimetric analysis. The compositions of carbon and hydrogen from the ultimate analysis show significant increases of 20-30% with increasing PB in the composite. The activation energy for RH is 101.22 kJ/mol; for x = 0.9 and 0.7, this increases by 4 and 6 magnitude, respectively, and for x = 0.5, shows remarkable increase to 165.30 kJ/mol. The range of temperature of about $480-660^{\circ}C$ is required for combustion of the composites $(RH)_x(PB)_{1-x}$ (x = (1, 0.9, 0.7, 0.5)) to perform the complete combustion process and produce high energy. In addition, the calorific value was determined by using bomb calorimetry, and shows value for RH of 13.44 MJ/kg, which increases about 30-40% with increasing PB content, indicating that PB has a strong effect of increasing the energy realized to generate electricity.

• Advances in concrete construction
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• v.3 no.3
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• pp.203-221
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• 2015

This paper presents the results of a study undertaken to investigate the enhancement of concrete strength using Silpozz and Rice Husk Ash (RHA). The total percentage of supplementary cementitious material (SCM) substituted in this study was 20%. Six different concrete mixes were prepared such as without replacement of cement with silpozz and RHA (0% silpozz and 0% RHA) is treated as conventional concrete, whereas in other five concrete mixes cement was replaced by 20% of silpozz and RHA as (0% silpozz and 20% RHA), (5% silpozz and 15% RHA), (10% silpozz and 10% RHA), (15% silpozz and 5% RHA) and (20% silpozz and 0% RHA) with decreasing water-binder (w/b) ratio i.e. 0.375, 0.325 and 0.275 and increasing super plasticiser dose. New generation polycarboxylate base water reducing admixture i.e., Cera Hyperplast XR-W40 was used in this study. The results of this research indicate that as w/b decreases, super plasticiser dose need to be increased so as to increase the workability of concrete. The effects of replacing cement by silpozz and RHA on the compressive strength, split tensile strength and flexural strength were evaluated. The concrete mixture with different combination of silpozz and RHA gives higher strength as compared to control specimen for all w/b ratios and also observed that the early age strength of concrete is more as compared to the later age strength. It is also observed that the strength enhancement of concrete mixture prepared with the combination of cement, silpozz and RHA is higher as compared to the concrete mixture prepared with cement and silpozz or cement and RHA.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.93-102
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• 2019

The materials of artificial soils in the production process of container seedlings have a great influence on plant growth. Peat moss, vermiculite, and perlite have been used as major components of artificial soils for many years; however, they could decrease carbon fixation carried out by the soil and cause environmental problems such as a change in the water quality. Thus, environmental friendly materials to replace them must be developed. The purpose of this study was to verify the optimum additive materials of artificial soils and their mixed ratios for the growth and seedling quality index (SQI) of Quercus serrata. Rice husk, mushroom sawdust, and pine bark were each used as an additive material and mixed into the growth medium at 10% and 20% of the total volume. There was no significant difference in the height growth of Q. serrata. The 20% mushroom sawdust decreased the root collar diameter by 23.4% compared to the control. The total dry weight was highest with the 10% rice husk and was significantly lower by 10.3% for the 20% mushroom sawdust compared to the control. Additionally, the SQI for all the treatments showed no tendency to increase compared with the control. Thus, this study showed the possibility of recycling biomaterials from agriculture and forest for seedling production. This method could reduce environmental problems and help eco-friendly nurseries to achieve a carbon negative impact by the recycling of by-products.

• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.155-160
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• 2019

The Korean Hanhyup broiler has commercialized native meat-type chicken. This study aimed to determine the effects of two types of litter material-sawdust and rice husk, and gender on the Korean Hanhyup broiler. Chicks (n=416) were randomly assigned in a $2{\times}2$ factorial design by type of litter material and gender. The behavior of chicken's was monitored continuously for 12 hours during the $1^{st}$ through $8^{th}$ week of age. The time spent on standing, sitting, and walking and the frequency of drinking, feeding, preening, dust bathing, flapping, and aggressive pecking, and pecking of chicken's behavior were recorded. The behavior of chickens during the starter (1 to 4 weeks) and finisher period (5 to 8 weeks) was compared to observe the changes upon maturity. Our results indicate that litter material type and gender have no effect on the behavior of chickens. However, aggressive pecking and pecking caused increment in the rice husk as compared to sawdust (P<0.05). Sawdust as litter material for bedding was found to be better than rice husk with respect to Korean Hanhyup broiler behavior.