• KSBB Journal
• /
• v.4 no.1
• /
• pp.21-30
• /
• 1989

Lauryl alcohol was used as extracting solvent of ethanol, and its toxicity on the free cells or immobilized cells was tested. To increase ethanol productivity, extractive fermentation method combined with ethanol fermentation and ethanol recovery was applied to the immobilized batch and continuous fermenter. As the concentration of LaOH was increased, the lag phase became longer, but specific growth rate did not change greatly. And a cell entrapment technique could protect the yeast cells against both substrate inhibition and solvent toxicity. When the glucose concentration was 400 g/l and the LaOH/fermentation medium ratio was 4, total ethanol productivity increased with the enhancement of LaOH volume, and maximum productivity was 2.75 g/l.hr in the immobilized batch fermentation.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.5
• /
• pp.341-345
• /
• 2009

Continuous dry anaerobic digestion of organic solid wastes (30% TS, Total Solids) comprised of food waste and paper was performed under mesophilic condition. During the operation, hydraulic retention time (HRT) was decreased as follows: 150 d, 100 d, 60 d, and 40 d, which corresponded to the solid loading rate of 2.0, 3.0, 5.0, and 7.5 kg TS/$m^3$/d, respectively. Volumetric biogas production rate ($m^3$/$m^3$/d) increased as HRT decreased, and the highest biogas production rate of 3.49${\pm}$0.31 $m^3$/$m^3$/d was achieved at 40 d of HRT. At this HRT, high volatile solids (VS) reduction of 76% was maintained, and methane production yield of 0.25 $m^3$/kg $TS_{added}$ was achieved, indicating 67.4% conversion of organic solid waste to bioenergy. The highest biogas production yield of 0.52 $m^3$/kg $TS_{added}$ was achieved at 100 d of HRT, but it did not change much with respect to HRT. For the ease feed pumping, some amount of digester sludge was recycled and mixed with fresh feed to decrease the solid content. Recirculation volume of 5Q was found to be the optimal in this experimental condition. Specific methanogenic activity (SMA) of microorganisms at mesophilic-dry condition was 2.66, 1.94, and 1.20 mL $CH_4$/g VS/d using acetate, butyrate, and propionate as a substrate, respectively.

• Journal of Korea Water Resources Association
• /
• v.51 no.8
• /
• pp.655-664
• /
• 2018

The riverbed material survey is to investigate the particle size distribution, specific gravity, porosity, etc. as basic data necessary for river channel plan such as calculation of sediment transport and change of river bed. In principle, the survey spots are 1 km interval in the longitudinal direction of the river and 3 points or more in the 1 cross section. Therefore, depending on longitudinal length of the river to be investigated, the number of surveyed sites is very large, and the time and cost for the investigation are correspondingly required. This study is to compare the particle size analysis method with the volumetric method and the image analysis method in work efficiency and cost and to examine the applicability of the image analysis method. It was confirmed that the diameter of the equivalent circle converted by the image analysis method can be applied to the analysis of bed material particle size. In the gravel stream with a particle size of less than 10 cm and a large shape factor, the analytical result of the bed material by the image analysis method is accurate. However, when the shape factor decreases as the particle size increases, the error increases. In addition, analysis results of the work efficiency and cost of the volume method and the image analysis method showed a reduction of about 80%.

• Journal of Radiation Protection and Research
• /
• v.23 no.4
• /
• pp.237-242
• /
• 1998

The goal of this work was to optimize the liquid scintillation counting techniques for the determination of C-14 in environmental samples such as biological and air samples. Carbon-14 activities in most environmental samples were measured with direct $CO_2$ absorption method. The highest figure of merit was found through the variation of Carbosorb $E^{TM}$ and Permatluor $V^{TM}$ ratio, in the measurement windows. The best condition was 1:1 volume ratio. Average 2.35 g of $CO_2$ was reproducibly absorbed in the 20 ml mixture within 40 min. The counting efficiency determined by repeated analysis of NIST oxalic acid standard and the background count rate were measured to be $58.8{\pm}1.4%$ and $1.88{\pm}0.06\;cpm$, respectively in case of saturated solution. The correction curves of counting efficiency for partially saturated solutions and for saturated solutions with quenching were prepared, respectively. The overall uncertainty of the sample specific activity for near background levels was estimated to be about 7 % for 4 hours counting at 95 % confidence level. The long-term stability of samples has been checked for all the counting techniques over a two week periods, and no apparent change in counting efficiency and background level was found at that time.

• Nutritional Sciences
• /
• v.9 no.2
• /
• pp.124-130
• /
• 2006

To examine the effects of alcohol consumption on body fluid restoration and fat mobilization following exercise induced dehydration, nine healthy collegiate men ($24{\pm}2yrs,\;177{\pm}5cm,\;72{\pm}8kg,\;10.5{\pm}2.3%$ body fat) underwent three experiments. In each experiment, subjects ran on a treadmill to reduce individual body mass to $2.2{\pm}0.1%$ and consumed one of three beverages containing 0, 4, or 8% alcohol over 60 min followed by 4 hr of resting recovery. They consumed approximately 150% of weight loss $(2053{\pm}204,\;2091{\pm}149,\;and\;1943{\pm}295mL)$ and content of alcohol was $9.9{\pm}1.0(0%),\;71.9{\pm}5.1(4%)$, and $132.2{\pm}20.1g$ (8% trial). Body weight, urine volume and samples, blood samples, and thirst sensation were measured five times; at baseline, immediately after exercise, and 0, 1st, and 4th hr of recovery. Blood alcohol concentration after ingestion was $0.0{\pm}0.0(0%),\;0.1{\pm}0.02(4%)$, and $0.2{\pm}0.03%$ (8% trial). No differences in blood sodium and potassium concentrations, and urine specific gravity were noticed over time periods and trials. Thirst sensation tended to be elevated in all trials immediately after exercises and urine output was elevated during the recovery. The magnitude of changes in these variables was proportional to the alcohol concentrations, but not statistically significant. While serum osmolality was not different among trials and time periods in 0 and 4% trials, it was higher during recovery than the baseline in the 8% trial (P<0.01). Triglycerides did not change throughout the time period and among trials. Free fatty acids were elevated after exercise in all trials and 4th hr of recovery in 0% (P<0.05). Subjects' net body fluid balance at 4th hr of recovery was negatively maintained and proportional to alcohol concentrations. Only 8% trials showed a significant reduction at 1st and 4th hr of recovery compared to 0 hr. The results suggested that diuretic effect of alcohol after moderate level of dehydration appeared dose dependent, but beverage containing alcohol up to 4% did not induce impaired rehydration than alcohol free drinks. Alcohol effects on fat mobilization during recovery appeared to be minimal and the mechanism is unclear.

• Journal of IKEEE
• /
• v.24 no.3
• /
• pp.754-765
• /
• 2020

Currently, Intelligent femoral prostheses that support the corresponding mode in walking and specific movements are being studied. Certain controls such as upstairs, sitting, and standing require a technique to classify control commands based on the user's intention because the mode must be changed before the operation. Therefore, in this paper, we propose a technique that can classify various control commands based on the user's intention in the intelligent thigh prosthesis system. If it is determined that the EMG signal needs to be compensated, the proposed technique compensates the EMG signal using the correlation between the strength and frequency components of the normal EMG signal and the muscle volume estimated by the pressure sensor. Through the experiment, it was confirmed that the user's intention was accurately detected even in the situation where muscle fatigue was accumulated. Improved intention detection techniques allow five control modes to be distinguished based on the number of muscle contractions within a given period of time. The results of the experiment confirmed that 97.5% accuracy was achieved through muscle tone compensation even if the strength of the muscle signal was different from normal due to muscle fatigue after exercise.

• Korean journal of food and cookery science
• /
• v.20 no.2
• /
• pp.180-186
• /
• 2004

Evidence shows there are flavonoid and polyphenol compounds in Ulmus cortex which has excellent antioxidant, anticancer and antimicrobial properties. This study summarizes our findings on effects of Ulmus cortex extracts(UDE) on quality characteristics of bread and the changes of microbial counts during storage. Dough yield and specific loaf volume of bread decreased significantly because the amount of UDE increased. Lightness of bread surface, redness of crumb and yellowness of crust were significantly increased. Texture evaluation showed that hardness was the highest in the bread prepared with 30% UDE. Sensory evaluation showed that odor, taste, texture, and overall acceptability were the best in bread which was made with 10% UDE. At the beginning of the period of storage, there were not significant differences of microbial cell count as increasing UDE, but significant decreasing was observed after passing 6 days. A negative correlation was generally observed between the sensory and mechanical properties. The results of total microbial count show that adding UDE in processing bread extend bread's storage time.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2005.06a
• /
• pp.476-484
• /
• 2005

This paper is to evaluate rather correctly $C^{14}$ ingestion dose that inhabitants around PWR plants can receive, and draw how to apply TF(Transfer Factor) to evaluate dose by the ingestion of animal products. For this, in this paper, dose assessment and analysis about existing materials related to TF were carried out, and the methodology to present TF was based on dose assessment and analysis result. The ingestion dose calculated using TFs presented by CSA and KEPRI was high or equal compared with SAM(Specific Activity Model) which is the most conservative, on the other hand, TFs given by NEC did not consider the effect according to volume change of animal at all, Therefore, it is judged that models used in the existing codes to asses the $C^{14}$ concentration into animal products must be improved to apply fundamentally hybrid model using transfer factors, that transfer factor on each animal products have to be developed through experiment for applying to our county.

• Applied Chemistry for Engineering
• /
• v.25 no.4
• /
• pp.401-408
• /
• 2014

In membrane bio-reactor (MBR), the aeration control is one of the important independent variables to decrease fouling and to save energy with shear stress change on the membrane surface. The paper was carried out for numerical simulation of 3-dimensional fluid flow phenomena of the cylindrical bioreactor with submerged flat membranes equipped in the center and supplied the air from the bottom by using the COMSOL program. The viscosity and temperature of solution were assumed to be constant, and the specific air demand based on permeate volume ($SAD_p$) defined as scouring air per permeate rates was used as a variable. The calculated CFD velocities were compared with those of the velocity meter measurement and video image analysis, respectively. The results were good agreement each other within 11% error. For fluid flow in the reactor the liquid velocity increased rapidly between the air diffuser and membrane module, but the velocity decreased during flowing of the membrane module. Also, the velocity increased as it was near from the reactor wall to the central axis. The calculated shear stress on the membrane surface showed the highest value at the center part of the module bottom side and increased as aeration rate increased. Especially, the wall shear stress increased dramatically as the aeration rate increased from 0.15 to 0.25 L/min.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.8
• /
• pp.1278-1284
• /
• 2003

This study was carried out to investigate the optimum conditions for making “sponge cake” with addition of ingredient, laver powder, and the quality characteristics of a new sponge cake. The moisture contents of sponge cake with 2, 4, 6% laver powder did not change but with 8 and 10%, the moisture contents increased to 28.89% and 30.69%, respectively. While specific gravity increased to 0.674 (control 0.493) when 10% laver powder was added, but volume was decreased. Most abundant mineral was Ca, followed by Na, Fe, Mn, Cu and Zn. The crust color degree of sponge cake with laver powder showed low marks on L, a, b. The crumb color degree showed low marks on L, b while “a” degree redness indicated highest marks with 4% laver powder. When it was seen under the microscope, the air cell numbers were decreased but the cell size became bigger. More free amino acid was contained when the laver powder was added. L-glutamic acid, L-alanine, L-aspartic acid and L-leucine were the major free amino acids. Hardness, springiness, cohesiveness, gumminess, chewiness and resilience degree of sponge cake with addition of laver power were higher than those of control. The sensory evaluation indicated that addition of 2% laver powder enhanced most mouth feeling, appearance, hardness, moistness, flavor and overall acceptability.