• 한국물환경학회지
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• 제25권1호
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• pp.159-166
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• 2009

This study has been attempted to generate electricity, while simultaneously treating artificial organic wastewater using both batch and continuous microbial fuel cells (MFCs). In the batch MFC, current-voltage curve showed an onset potential of -0.69 V vs. Ag/AgCl. The potential range between this potential and 0 potential displayed an available voltage for an automatic production of electric energy and glucose, which was oxidized and treated at the same time. The 486 mg/L glucose solution showed the maximum power of $30mW/m^2$ and the maximum current density of $75mA/m^2$ shown in the power curve. As a result, discharging of the cell containing COD 423 mg/L at the constant current density of $60mA/m^2$ showed a continuous electricity generation for about 22 hours that dropped rapidly due to dissipating of organic material. Total electric energy production was 18.0 Wh. While discharging, the pH change was low and dropped from pH 6.53 to 6.20 then increased to 6.47, then stabilized at this charge. The COD treatment efficiency was found to be 72%. In the continuous MFC, COD removal tends to increase as the hydraulic retention time is increased. At one day of hydraulic retention time as the maximum value reaches the COD removal efficiency, power production rate and power production rate per COD removal that were obtained were 68.8%, $14mW/m^2$, and $20.8mW/m^2/g$ CODrm, respectively. In the continuous MFC, the power production rate per COD removal increases as the hydraulic retention time is increased and decreases as the organic loading rate is increased. At the values lower than an organic loading rate of $1kgCOD/m^3/d$, the values higher than about $18.1mW/m^2/g$ CODrm could be obtained.

• Asian-Australasian Journal of Animal Sciences
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• 제15권9호
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• pp.1273-1277
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• 2002

The effect of urea treatment on chemical composition of neem seed kernel cake (NSKC) was investigated by soaking the cake in 2.1% urea solution (1.2 l $kg^{-1}$ NSKC) for five days. The effect on utilisation of nutrients by replacing groundnut cake (GNC) (30%) with urea-treated neem seed kernel cake (UTNSKC) (33%) in a concentrate mixture fed to meet 70% of the protein requirements of lambs (8 males and 8 females), was monitored in a digestibility study. Following urea treatment of NSKC only 9.5% of urea was hydrolysed and the crude protein content of the cake was increased by 6.65%. The tannin content in depulped neem seeds was 37% catechin equivalent. Whereas feeding UTNSKC had no effect on intake of dry matter (72.5 vs 66.3 g/kg $BW^{0.75}day^{-1}$) and digestibility of crude fibre (41.3 vs 43.4%), the cake depressed (p<0.01) the percent digestibility of dry matter (63.7 vs 70.2), crude protein (63.2 vs 70.2), nitrogen free extract (73.8 vs 80.5) and gross energy (64.3 vs 69.1). Digestibility of ether extract (75.8 vs 70.9%) was higher (p<0.05) in animals offered UTNSKC. The nutritive value of the composite ration consumed by lambs offered UTNSKC was lower (p<0.01) in terms of total digestible nutrients (64.7 vs 70.2%) and digestible energy (2.8 vs 3.0 Kcal/g DM). Intake of digestible energy (199.8 vs 194.1 Kcal/kg $BW^{0.75}day^{-1}$) and retention of nitrogen (7.53 vs 8.23 g $day^{-1}$) and calcium (2.12 vs 1.84 g $day^{-1}$) were comparable on the 2 rations. Animals fed UTNSKC retained less (p<0.01) phosphorus (0.37 vs 1.05 g $day^{-1}$). The results indicate that urea treatment increased the protein level of NSKC whereas feeding the treated cake as a replacement of GNC, lowered the digestibility of nutrients and retention of phosphorus.

• 한국의학물리학회지:의학물리
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• 제9권4호
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• pp.259-266
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• 1998

코발트-60 근접조사선원을 대체할 Ir-l92 선원주변의 2차원적 선량분포를 얻기 위하여, 조사선량률과, 조직감쇠계수를 구하였다. 조직감쇠계수는 선원에서 20 cm 지점까지 실험식을 구하였다. ？보기 방사능은 조사선량상수를 사용하여 결정하였으며, 2.5mm 직경에 두께 2.5 mm 의 선원은 조직선량을 정하기 위해 선원을 4401 개로 분할하여 선원 자체의 흡수효과와 ？슐벽의 차폐 효과와 조직감쇠계수를 적용하였다. 조직감쇠계수는 4차식을 사용하여 1% 오차범위내에서 실험값을 얻을 수 있었으며, Meisberger 상수는 선원에서 많이 떨어질수록 오차가 커서, 10 cm 위치서 7%, 20 cm 에서 33%의 오차를 발견할 수 있었으나, 겉보기방사능과 선원모양 및 크기가 달라 다른 결과를 가져올 수 있다고 본다. 발표된 Ir-192 선원의 에너지스펙트럼을 이용한 선량률상수는 절삭에너지 10 keV인 경우 4.69 R$cm^2$/mCi-hr을 얻었으며 Air Kerma는 0.973 을 구하였다. 이 실험에서 고안 선원의 분할선원에 의한 선원자체흡수와 ？슐벽에 의한 감쇠는 실선원의 54.6%가 겉보기방사능으로 나타남을 알 수 있었으며, 선량계획에 이용하기 위해 단위 ？보기 방사능에 대한 2차원적 선량표를 준비함으로써 기하학적선량과 선량 비등방성을 쉽게 이용할 수 있도록 하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권9호
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• pp.1278-1284
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• 2000

An experiment was performed to evaluate different methods for preserving shrimp by-products and to determine their chemical composition. In the first experiment three ratios of shrimp by-product (SBP) to molasses (6:1, 4:1 and 3:1, wet weight), and to cassava root meal (3:1, 2:1 and 1:1, wet weight of shrimp by-product and air-dry weight of cassava root meal) were investigated. The pH of the SBP ensiled with molasses at a ratio of 3:1, and with cassava root meal at a ratio of 1:1, decreased during the first week to below 4.5 and remained low up to day 56 of ensiling, whereas the pH of the mixtures with higher ratios of SBP remained above 7.0, and the material deteriorated rapidly. The dry matter decreased initially in all treatments but then increased slightly from day 28 in the treatment where shrimp by-product was ensiled with cassava root meal at a ratio of 1:1. The crude protein (CP) and ammonia-N $(NH_3-N)$ contents of the preserved shrimp by-product material ensiled with molasses at a ratio of 3:1 increased significantly one week after ensiling. The CP content then remained constant, while the $NH_3-N$ concentration continued to increase up to 56 days after ensiling. When SBP was ensiled with cassava root meal at a ratio of 1:1 the CP content of the silage increased significantly up to 21 days after ensiling and then decreased back to the original level after 56 days, whereas $NH_3-N$ increased markedly up to 14 days and then remained fairly constant up to 56 days. However, the $NH_3-N$ content was significantly higher when SBP was ensiled with cassava root meal than with molasses. A balance experiment was carried out, arranged as a double Latin-square and including 6 F1 (Large White ${\times}$ Mong Cai) castrates fed randomly one of three diets based on cassava root meal, rice bran, and fish meal (FM) or shrimp by-product ensiled with molasses (SBEMO) or with cassava root meal (SBECA) as the main protein source. Apparent organic matter and CP digestibilities were significantly (p<0.001) higher for the fish meal diet than for the two shrimp by-product diets, although CP digestibility in SBEMO and SBECA was similar (p>0.05). N-retention was significantly higher for the fish meal diet than for the SBEMO diet, which in turn was significantly higher than for the SBECA diet (p<0.01). It can be concluded that shrimp by-product can be preserved by ensiling with molasses at a ratio of 3:1 or with cassava root meal at a ratio of 1:1. Nutrient digestibility and N-retention of diets based on these shrimp by-product silages were lower than for similar diets based on fish meal, probably due to their high chitin content and inferior amino acid balance.

• Biomolecules & Therapeutics
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• 제6권3호
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• pp.289-295
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• 1998

The bioequivalence of two nilvadipine products was evaluated in 16 normal male volunteers (age 22-32 yr, body weight 57-80 kg) following sidle oral dose. Test product was Overca $l_{R}$ tablet (Choong-Wae Pharm. Corp., Korea) and reference product was Nivadi $l_{R}$ tablet (Hyundai Pharm. Corp., Korea). Both products contain 4 mg of nilvadipine. One tablet of the test or the reference product was administered to the volunteers, respectively, by randomized two period cross-over study (2$\times$2 Latin square method). The determination of nilvadipine was accomplished using a validated capillary column GC with electron-capture detection. As a result of the assay validation, the quantiflcation of nilvadipine in human plasma by this technique was possible down to 0.5 ng/ml using 1 ml of plasma. Absolute overall recovery from five replicate analyses of nilvadipine-spiked sample were 88.4$\pm$ 10.24% (mean$\pm$ 5.D.) for human plasma of 10 ng/ml. The coefficients of variation (C.V.) were less than 20% and the actual concentration of nilvadipine measured by GC ranged from 80 to 99% in all plasma. Average drug concentrations at each sampling time and pharmacokinetic parameters calculated were not significantly different between two products (p>0.05); the area under the curve from time zero to 8 hr (AUCo-$_{8 hr}$) (22.8$\pm$5.90 vs 22.2$\pm$6.10 ng . hr/ml), maximum plasma concentration ( $C_{max}$) (10.0$\pm$2.85 vs 9.3$\pm$3.28 ng/ml) and time to reach maximum plasma concentration ( $T_{max}$) (1.2$\pm$0.31 vs 1.3 $\pm$0.47 hr). The differences of mean AU $Co_{8hr}$ $C_{max}$, and $T_{max}$ between the two products (2.25, 7.65, and 10.30%, respectively) were less than 20%. The power (1-$\beta$) and treaeent difference (7) for AU $Co_{8hr}$, and $C_{max}$ were more than 0.8 and less than 0.2, respectively. Although the power for Tmax was under 0.8, Tm\ulcorner of the two products was not significantly different from each other (p>0. 05). These results suggest that the bioavailability of Overeat tablet is not significantly different from that of Nivadil tablet. Therefore, two products are bioequivalent based on the current results.sults.lts.lts.lts.

• Bulletin of the Korean Chemical Society
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• 제17권9호
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• pp.794-798
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• 1996

Solid solutions of the nonstoichiometric Dy1-xSrxCoO3-y system with the compositions of x=0.00, 0.25, 0.50, 0.75, and 1.00 have been synthesized by the solid state reaction at 1000 ℃ under atmospheric air pressure. The crystallographic structures of the solid solutions are analyzed by the powder X-ray diffraction patterns at room temperature. The analyses assign the compositions of x=0.00 and 0.25 to the orthorhombic system with space group of Pbnm/D2h16, the compositions of x=0.50 and 0.75 to the tetragonal system like a typical SrCoO2.86, and the composition of x=l.00 or SrCoO2.50 to the brownmillerite type system with space group of I**a. The reduced lattice volumes increase with x value due to the larger radius of Sr2+ ion than that of Dy3+ ion. The mole ratio of Co4+ ion to total Co ion with mixed valence state between Co3+ and Co4+ ions at B sites or τ value has been determined by an iodometric titration. All the samples except for the DyCoO3 compound show the mixed valnce state and thus the composition of x=0.50 has the maximum τ value in the system. The oxygen vacancies increasing with x value are randomly distributed over the crystal lattice except for the composition of x=l.00 which have the ordering of the oxygen vacancies. The nonstoichiometric chemical formulas of the Dy1-xSrxCo3+1-τCo4+τO3-(x-τ)/2 system are formulated from the x, τ, and y values. The electrical conductivity in the temperature range of 100 to 900 K increases with τ value linearly because of positive holes of the Co4+ ions in π* band as a conducting carrier. The activation energy of the x=0.50 as Ea=0.17 eV is minimum among other compouds. Broad and high order transition due to the overlap between σ* and π* bands broadened by the thermal activation is observed near 1000 K and shows a low temperature-semiconducting behavior. Magnetic properties following the Currie-Weiss law show the low to high spin transition in the cobaltate perovskite. Especially, the composition of x=0.75 presents weak ferromagnetic behavior due to the Co3+-O2--Co4+ indirect superexchange interaction.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권4호
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• pp.202-208
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• 2001

In Recent results suggested that doping $Ta_2O_5$ with a small amount of $TiO_2$ using standard ceramic processing techniques can increase the dielectric constant of $Ta_2O_5$ significantly. In this paper, this concept is studied using RTCVD (Rapid Thermal Chemical Vapor Deposition). Ti-doped $Ta_2O_5$ films are deposited using $TaC_{12}H_{30}O_5N$, $C_8H_{24}N_4Ti$, and $O_2$ on both Si and $NH_3$-nitrided Si substrates. An $NH_3$-based interface layer at the Si surface is used to prevent interfacial oxidation during the CVD process and post deposition annealing is performed in $H_2/O_2$ ambient to improve film quality and reduce leakage current. A sputtered TiN layer is used as a diffusion barrier between the Al gate electrode and the $TaTi_xO_y$ dielectric. XPS analyses confirm the formation of a ($Ta_2O_5)_{1-x}(TiO_2)_x$ composite oxide. A high quality $TaTi_xO_y$ gate stack with EOT (Equivalent Oxide Thickness) of $7{\AA}$ and leakage current $Jg=O.5A/textrm{cm}^2$ @ Vg=-1.0V has been achieved. We have also succeeded in forming a $TaTi_x/O_y$ composite oxide by rapid thermal oxidation of the as-deposited CVD TaTi films. The electrical properties and Jg-EOT characteristics of these composite oxides are remarkably similar to that of RTCVD $Ta_2O_5, suggesting that the dielectric constant of $Ta_2O_5$ is not affected by the addition of $TiO_2$.

• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.74-81
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• 2010

The effects of different levels of natural clay enterosorbent on the growth, nutrient availability, and genital organs of post-weaning female pigs fed with an addition of zearalenone (ZEA) were investigated in the study. A total of thirty-five post-weaning gilts ($L{\times}Y{\times}D$) with an average body weight of 12.36${\pm}$1.46 kg were used in the test. The gilts were raised individually in metabolism cages and fed a corn-soybean meal-whey basal diet with an addition of 0 or 1 mg/kg of ZEA for 24 d with four levels of natural clay enterosorbent added in the feed. The treatments were: i) control; ii) control+2.5 g/kg clay; iii) control+1 mg/kg ZEA; iv) control+1 mg/kg ZEA+1.25 g/kg clay; v) control+1 mg/kg ZEA+2.5 g/kg clay; vi) control+1 mg/kg ZEA+5.0 g/kg clay; vii) control+1 mg/kg ZEA +10 g/kg clay. Pigs fed diets contaminated with additional purified ZEA had significantly reduced apparent digestibility of crude protein (CP), gross energy (GE) and apparent metabolic rate of GE (ME/GE, p<0.05) without changes of net protein utilization (NPU, p>0.05). Final body weight, average daily gain (ADG), average daily feed intake (ADFI), vulva length, vulva width, vulva area, relative weights of genital organ and proliferative changes of the ovary tissues in gilts fed ZEA-contaminated diet were increased (p<0.05) compared to the gilts fed the control diet. Addition of natural clay enterosorbent in the ZEA-contaminated diet showed a positive protection effect on ZEA feeding, and the protection was increased linearly or quadratically as clay content increased. However, in pigs fed a diet with clay alone at 2.5 g/kg level there was no significant impact (p>0.05) on all the parameters as compared to the control. It is suggested that feeding ZEA at about 1.0 mg/kg for 24 days might result in a deleterious effect in pigs, and addition of 5 or 10 g clay enterosorbent per kg diet can effectively neutralize the detrimental effects of the ZEA feeding.

• 한국식품영양과학회지
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• 제40권2호
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• pp.214-222
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• 2011

천년초에 존재하는 점질다당의 새로운 이용방안을 모색하기 위해 천년초로부터 다당을 분리하여 항전이 활성을 평가하고 구조 분석을 행하였다. B16BL6 종양세포를 이용한 폐암 전이모델에서 천년초 조다당 CNC-0는 농도 의존적으로 높은 항전이 활성을 나타냈다. 천년초 조다당 CNC-0는 DEAE-Sepharose FF 및 Sephadex G-75를 이용한 연속적 chromatography를 행하여 CNC-Ia으로 정제하고 이들의 구조적 특성을 검토하였다. CNC-Ia는 분자량 약 700 kDa의 다당체로 구성당 조성을 확인한 결과, arabinose, galactose 및 xylose를 높은 비율로 함유하고 있었으며 rhamnose와 fucose를 미량 함유하고 있었다. 본 당쇄의 결합양식을 규명하기 위해 methylation analysis를 행한 결과 CNC-Ia은 terminal Araf, 5-linked Araf, 4-linked Galp, terminal Xylp와를 포함한 총 18종의 결합으로 구성되어 있었으며 full branched Araf, 3,4,6-branched Galp 및 full branched Galp 와 같은 3종의 CNC-Ia 고유의 특징적 결합을 포함하고 있었다. 또한 CNC-Ia의 미세구조를 규명하기 위해 exo-${\alpha}$-Larabinofuranosidase와 endo-${\beta}$-1,4-D-galactanase를 이용한 연속 가수분해 및 해석도 행하였다. 이상의 결과로부터 천년초 유래 다당 CNC-Ia는 ${\beta}$-($1{\rightarrow}4$)-galactan 주쇄에 arabinose oligo당이 측쇄로 분지된 Type I arabinogalactan으로 판단되었으며 주쇄 및 측쇄 모두 고도로 분지된 특징이 있음을 알 수 있었다.

• Steel and Composite Structures
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• 제34권5호
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.