• 원예과학기술지
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• 제31권1호
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• pp.103-109
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• 2013

Estimating the high tuber solids needs a simulation system on potato growth, and its development should be obtained by using agricultural elements which analyze the relationship between crop growth and agricultural factors. An accurate simulation to predict solids level against climatic change employs a calculation of in vivo energy consumption and bias for growth and induction shape in a slight environmental adaptation. So, to calculate in vivo energy consumption, this study took a concept of estimate of the amount of basal metabolism in each tuber. In the validation experiments, the results of measuring solid accumulation of potatoes harvested at dates suggested by simulation agreed with the actual measured values in each regional field during the growth period of years from 2006 till 2010. The mean values of tuber solids level and inter-annual level variation in validation experiments were predicted well by the simulation model. And also, the results of validation experiments represent that concentration of tuber solids were due mainly to the duration of sunshine, above 190 hours per a month, and the cumulative amount of radiation, above 2,200 $MJ{\cdot}m^{-2}$, of the effective growth period.

• 물과 미래
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• 제25권2호
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• pp.67-78
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• 1992

Several field surveys were conducted to investigate changes of water quality with time in a tidal river. Results indicated that nitrification process were dependent on the change of salinity and suspended solids concenttration. Therefore laboratory batch experiments were conducted, using suspended solids and sediment taken from a tidal river, to study the effect of salinity on nitrification and to estimate kinetic parameters of it in the tidal river. suspended solids and sediment were sampled at a point in the middle stream. Sediments were collect from the aerobic layer of mud. The change of nitrogen concentration with time was clearly explained with Monod groth model and kinetic parameters were obtained by curve fitting method. Changes in NH4-N, NO2-N, and NO3-N concentrations in the river ROKKAU with time were simulated well using Lagrangian reference frame and parameter values obtained in the laboratory tests. T도 mechanism of nitrification by suspended solids and sediment in a tidal river is shown to depend on tidal effects.

• Journal of the Korean Wood Science and Technology
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• 제35권5호
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• pp.67-75
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• 2007

As a part of abating the formaldehyde emission of urea-formaldehyde (UF) resin adhesive by lowering formaldehyde to urea (F/U) mole ratio, this study was conducted to investigate properties of UF resin adhesive with different F/U mole ratios. UF resin adhesives were synthesized at different F/U mole ratios of 1.6, 1.4, 1.2, and 1.0. Properties of UF resin adhesives measured were non-volatile solids content, pH level, viscosity, water tolerance, specific gravity, gel time and free formaldehyde content. In addition, a linear relationship between non-volatile solids content and sucrose concentration measured by a refractometer was established for a faster determination of the non-volatile solids content of UF resin. As F/U mole ratio was lowered, non-volatile solids content, pH, specific gravity, water tolerance, and gel time increased while free formaldehyde content and viscosity were decreased. These results suggested that the amount of free formaldehyde strongly affected the reactivity of UF resin. Lowering F/U mole ratio of UF resin as a way of abating formaldehyde emission consequently requires improving its reactivity.

• 미생물학회지
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• 제24권4호
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• pp.385-388
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• 1986

고상 발효의 기초적인 애커니즘을 규명하기 위하여 고행화된 배지속에 8앙 효모을 증식시켰마. 이때 실험 배지는 Maxon ] Johnson배지 이었으며, 고형화 물질로는 갈근에서 얻은 전분을 푸깨비로 6-12%를 첨가하였다. 전분이 6-8% 첨가 될때 보 다도 10←12% 첨가될 때 효모의 증식이 8-24시간에서 훨씬 빨랐으며, 단백잘의 분바양도 전분을 10% 첨가 하었을때 10-24시 간에서 가장 높았다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.435-440
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• 2001

Piezoelectric solids such as PZT and PLZT have been widely used as sensors and actuators for various smart systems. One of the problems arising in actuator applications is that a larger actuation force needs to be produced from a small system. This naturally leads to local electric field or stress concentration and thereby resulting in a nonlinear behavior inside the system, Hence, it becomes more important to predict the nonlinear behavior of piezoelectric solids. In this paper we investigate the mechanism of nonlinear behavior in those materials and suggest a constitutive and finite element model. The calculation results obtained from the model seem to be qualitatively consistent with experiments.

• 상하수도학회지
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• 제18권6호
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• pp.715-723
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• 2004

The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS occurs under quiescent conditions in the primary clarifier, where suspended solids are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. The relative solid and liquid fractions of a slurry are most commonly described by the solids concentration, expressed as mg/L or percent solids. The purpose of the present investigation is to estimate a suitability on the design capacities of residuals treatment facilities by the quantity of dewatered sludge generated from water treatment plants.

• 해양환경안전학회지
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• 제14권3호
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• pp.183-187
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• 2008

연안개발에 의하여 해양으로 유입되는 부유토사는 해양생태계에 많은 영향을 미칠 것으로 판단된다. 따라서 본 연구에서는 참전복, Haliotis discus hannai 치패를 이용하여 부유토사 농도 변화에 따른 폐사율 및 글리코겐 함량 변화에 대해 알아보았다. $0{\sim}2,000\;mg/L$의 부유토사 농도구에서 96시간 동안 노출을 행한 결과 전복의 폐사는 일어나지 않았으나 연체부의 글리코겐 함량에 있어서는 1,500 mg/L 이상의 농도구에서 유의하게 감소하였다. 본 연구결과로부터 부유토사가 전복의 폐사에는 직접적인 영향을 미치지는 않으나 부유토사에 의하여 건강상 장해를 일으킬 수 있을 것으로 판단되며 장기적으로 발생할 수 있는 부유토사의 영향을 고려하여 양식장으로의 토사유입을 방지 할 수 있는 대비책을 마련해야 할 것이다.

• 한국환경과학회지
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• 제1권2호
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• pp.125-136
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• 1992

Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor (ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content fined. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at 35$^{\circ}C$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed In the ASBRS in spite of withdrawal and replenishment of 30% or 40% of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about 70% of the working volume of the reactor Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested flu형e in the ASBR was 2.9 times higher than that of the flu형e in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of 52% was observed at the ASBRS compared with the control reactor in spite of similar quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated.

• 한국식품과학회지
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• 제20권2호
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• pp.205-212
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• 1988

마늘의 영하온도에서 저장시 나타나는 내한성(耐寒性)의 원인규명을 위하여 인편의 성분조성이 빙점 강하에 미치는 영향에 대하여 시험하였다. 생체(生體)마늘의 성분조성의 특징은 가용성고형분이 $40^{\circ}$ Brix(건물기준액 90%)로 일반과채류의 $10^{\circ}$ Brix에 비(比)하여 월등히 높았으며 그 구성은 총 90%중 당류가 70% 단백질이 20%였다 그리고 불용성 고형분 10%의 조성은 회분 3% 조섬유 3%였고 그외 지방, 탄수화물 및 단백질을 합(合)하여 4%정도로 되어 있었다. 마늘 성분중 당류는 fructosan이 주종(主種)이었으며 이들은 $1{\sim}29$ 중합도(Polymerization degree)의 것이 혼재되어 있으며 특히 $4{\sim}5$중합도의 것이 전체 50%이상으로 가장 많았다. 마늘의 내한성 지표인 빙점은 수용성고형분 농도가 높을수록 낮았고 동일농도일 경우에는 저중합도(低重合度)의 fructosan일수록 낮았다.

• Food Science and Biotechnology
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• 제15권2호
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• pp.196-201
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• 2006

Freeze concentration of milk was carried out thorough the controlled recrystallization of ice in a multi-stage freeze concentrator. Artificial temperature control was used to induce ice recrystallization via a heat and cold shock process. In each stage of freeze concentration, the recrystallization time was fixed at 1, 2, 4, and 8 hr to compare the solute concentrate, yield, Brix, ice crystal size, and freezing point at each experimental condition. Higher concentrations of milk solids were seen with increased durations of recrystallization time, and a maximum total solids in the final product of 32.7% was obtained with a ripening time of 8 hr in a second stage process. Milk solid yield decreased according to the solute concentration and recrystallization time. The results of Brix and ice crystal size showed a positive correlation with recrystallizaiton time. These results suggest the possibility of freeze concentration being of practical use in the dairy industry.