• Title/Summary/Keyword: k Out of n

Search Result 5,849, Processing Time 0.039 seconds

Optimization of Operational Conditions of Existing BNR Process with Various C/N Ratio using Simulation Method (시뮬레이션 기법을 이용한 기존 BNR공정의 C/N비 변화에 따른 운전조건 최적화)

  • Rho, Hae-Yeon;Gil, Kyung-Ik
    • Journal of Korean Society on Water Environment
    • /
    • v.23 no.3
    • /
    • pp.367-370
    • /
    • 2007
  • Numerous sets of simulation were conducted in order to find out the optimum operational conditions of the existing BNR process using GPS-X program. The model of ASM3 and modified Bio-P module were applied for simulations. From the result of this study, effluent quality was closely related with the step feeding rate and influent C/N ratio. The effluent TN concentration seemed to be significantly affected by step feeding rate at the low C/N condition. But at the high C/N condition, the effluent concentration of TP rather than that of TN was affected by the control of step feeding rate.

On-off Dewatering Control for Lipase-catalyzed Synthesis of n-Butyl Oleate in n-Hexane by Tubular Type Pervaporation System

  • Kwon, Seok-Joon;Rhee, Joon-Shick
    • Journal of Microbiology and Biotechnology
    • /
    • v.8 no.2
    • /
    • pp.165-170
    • /
    • 1998
  • Lipase-catalyzed esterification of n-butyl oleate was carried out in n-hexane as a model reaction. The optimal activity of Candida rugosa lipase was shown in a water activity ($a_w$) range of 0.52 to 0.65 at $30^{\circ}C$. The water produced from the esterification was removed by a tubular type pervaporation system. The rate of ester formed from the enzymatic esterification was allowed to be the same as the rate of water removal by maintaining an optimal $a_w$ of the reaction system using an on-off dewatering control device. The reaction rate and yield with a$a_w$ control were increased two folds higher than the respective values for the uncontrolled reaction.

  • PDF

Processing Characteristics of Nylon 6 by Controlling the Melt Viscosity (용융 점도 조절에 의한 나일론6의 가공특성 연구)

  • Kim Hyogap;Kim Jun Kyung;Lim Soonho;Lee Kunwong;Park Min;Kang Ho-Jong
    • Polymer(Korea)
    • /
    • v.29 no.6
    • /
    • pp.565-570
    • /
    • 2005
  • Melt processing characteristics of nylon 6 (N6) has been investigated by controlling the melt viscosity in melt impregnation process. Calcium stearate (CaST) was introduced as a lubricant for N6 and the melt viscosity of N6 decreased with adding only 1 wt$\%$ of CaST. In addition, reactive blending with polycaprolactone (PCL) was carried out by lowering the melt viscosity in N6. It was found that the melt viscosity of N6 could be controlled and further melt viscosity drop could be obtained by applying phenyl phosphite (PP) and diphenyl phosphite (DPP) to enhance the transesterification between N6 and PCL. Our approaches show that the melt viscosity of N6 could be reduced without loss of thermal stability which is the critical problem in high temperature melt impregnation process of N6.

Diagnostic Imaging Features of Abdominal Foreign Body in Dogs; Retained Surgical Gauze (개에서 복강내 잔존한 거즈 이물의 진단영상)

  • Choi, Ji-Hye;Kim, Gye-Dong;Keh, Seo-Yeun;Jang, Jae-Yong;Choi, Hee-Yeon;Yoon, Jung-Hee
    • Journal of Veterinary Clinics
    • /
    • v.28 no.1
    • /
    • pp.94-100
    • /
    • 2011
  • This study was performed to describe the radiographic and ultrasonographic features of retained surgical gauze known as gossypiboma in 9 dogs. Female dogs (n = 8) were at higher risk and seven out of the eight cases had a history of ovariohysterectomy. Seven dogs were symptomatic and the most common clinical signs were vomiting, anorexia, and inertia. A palpable abdominal mass was detected in six dogs. Radiographic signs included a localized abdominal mass with soft tissue density (n = 7) or a mass containing speckled gas (n = 1). Ultrasonography showed a hypoechoic mass with a hyperechoic center (n = 4), or a homogeneous hypoechoic mass (n = 3). The remaining dogs (n = 2) showed an intestinal wall surrounding a hyperechoic center. Regardless of the characteristics of a mass, an acoustic shadowing was accompanied from the center of a mass in all dogs. Ultrasonography also revealed complications such as adhesion between a mass and adjacent organs, and peritonitis and intestinal obstruction around a mass. The gossypiboma can be considered when a hypoechoic mass accompanying a hyperechoic center with acoustic shadowing is observed on ultrasound examination.

Basicity of Urea: Near-Infrared Spectroscopic and Theoretical Studies on the Hydrogen Bonding Ability of TMU and DMDPU

  • 이호진;최영상;박정희;윤창주
    • Bulletin of the Korean Chemical Society
    • /
    • v.19 no.1
    • /
    • pp.110-114
    • /
    • 1998
  • The hydrogen-bonding interactions between thioacetamide (TA) and urea derivatives such as tetramethylurea (TMU) and dimethyldiphenylurea (DMDPU) have been studied using near-infrared absorption spectroscopy. Thermodynamic parameters for the interactions between TA and urea derivatives were determined by analyzing the $v^{as}_{N-H}$+Amide Ⅱ combination band of TA at 1970 nm. The ΔH° values, indicating the intrinsic strength of hydrogen bonding, are - 23.0 kJ/mole and - 19.8 kJ/mol for TMU and DMDPU, respectively. This is well explained by the inductive effects of substituents. Ab initio molecular orbital calculations for the proton affinity of TMU, N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA) in gas phase have been carried out at HF/3-21G ad HF/6-31G(d) levels, showing that the proton affinity of TMU is larger than that of DMA, which agrees well the experimental results.

Antibody reaction of human anti-Toxoplasma gondii positive and negative sera with Neospora caninum antigens (톡소포자충 양성 및 음성인 사람 혈청에 대한 네오포자충 (Neospora caninum))

  • Ho-Woo NAM;Seung-Won KANG;Won-Young CHOI
    • Parasites, Hosts and Diseases
    • /
    • v.36 no.4
    • /
    • pp.269-275
    • /
    • 1998
  • Anti-Neospora caninum antibody was detected in anti-Toxoplasma gondii positive and negative human sera by ELISA, western blot and immunofluorescence assay (IFA). Twelve cases out of 172 (6.7%) Toxoplasma-positive sera cross-reacted with both T. gondii and N. caninum antigens, and one out of 110 Toxoplasma-negative sera reacted with N. caninum antigen by ELISA. By western blot, all 12 sera reacted with T. gondii antigens with various banding patterns but specifically at 30 kDa (SAG 1), and 22 kDa (SAG2) bands. With N. caninum antigen, the number of reactive bands was reduced, however a 43 kDa band reacted in three cases in Toxoplasma-positive sera in addition to one in Toxoplasma-negative control sera. All sera of the Toxoplasma-positive group labeled surface membrane of T. gondii, but reacted differently with N. caninum. Fluorescence was detected in surface membrane, subcellular organelles, or both in N. caninum. And one case in the Toxoplasma-negative group also reacted with N. caninum strongly in subcellular organelles. This suggested that the antibody against N. caninum may be present in human sera although the positive rate was very low in this study. The possibility of human infection with N. caninum remains to be evaluated further.

  • PDF

RINGS WITH THE SYMMETRIC PROPERTY FOR IDEMPOTENT-PRODUCTS

  • Han, Juncheol;Sim, Hyo-Seob
    • East Asian mathematical journal
    • /
    • v.34 no.5
    • /
    • pp.615-621
    • /
    • 2018
  • Let R be a ring with the unity 1, and let e be an idempotent of R. In this paper, we discuss some symmetric property for the set $\{(a_1,a_2,{\cdots},a_n){\in}R^n:a_1a_2{\cdots}a_n=e\}$. We here investigate some properties of those rings with such a symmetric property for an arbitrary idempotent e; some of our results turn out to generalize some known results observed already when n = 2 and e = 0, 1 by several authors. We also focus especially on the case when n = 3 and e = 1. As consequences of our observation, we also give some equivalent conditions to the commutativity for some classes of rings, in terms of the symmetric property.

Efficient Generation of Computer-generated Hologram Patterns Using Spatially Redundant Data on a 3D Object and the Novel Look-up Table Method

  • Kim, Seung-Cheol;Kim, Eun-Soo
    • Journal of Information Display
    • /
    • v.10 no.1
    • /
    • pp.6-15
    • /
    • 2009
  • In this paper, a new approach is proposed for the efficient generation of computer-generated holograms (CGHs) using the spatially redundant data on a 3D object and the novel look-up table (N-LUT) method. First, the pre-calculated N-point principle fringe patterns (PFPs) were calculated using the 1-point PFP of the N-LUT. Second, spatially redundant data on a 3D object were extracted and re-grouped into the N-point redundancy map using the run-length encoding (RLE) method. Then CGH patterns were generated using the spatial redundancy map and the N-LUT method. Finally, the generated hologram patterns were reconstructed. In this approach, the object points that were involved in the calculation of the CGH patterns were dramatically reduced, due to which the computational speed was increased. Some experiments with a test 3D object were carried out and the results were compared with those of conventional methods.

A Study on the Characteristics of Groundwaters in Gyeongsan City (경산시 지하수의 수질특성에 관한 연구)

  • Song, Sung-Sook;Park, Byoung-Yoon;Lee, Bu-Yong
    • Journal of Environmental Science International
    • /
    • v.16 no.6
    • /
    • pp.677-682
    • /
    • 2007
  • This study was performed to provide the basic information on characteristics of groundwater pollution in Gyeongsan city. Forty two groundwater samples were collected, and pH, DO, COD, $NH_3-N,\;NO_3^--N$, T-N, $PO_4^{3-}-P$, Cl, Ca, Mg, hardness, evaporate residues and others were investigated. And, ANOVA analyses were carried out to reveal the differences in water pollution indicator values of by industry, commerce/residence and agriculture areas. The results were as follows. 1. The mean values of pH, DO, COD, $NH_3-N,\;NO_3^--N$, T-N, $PO_4^{3-}-P$, Cl, evaporate residues, Ca and hardness were 6.9, $7.9mg/\ell,\;0.4mg/\ell,\;2.44mg/\ell,\;2.73mg/\ell,\;6.06mg/\ell,\;0.82mg/\ell,\;32.72mg/\ell,\;381.67mg/\ell,\;41.53mg/\ell,\;177.17mg/\ell$, respectively. 2. As groundwater became deeper, the values of Cl, Ca, Mg, Na, hardness and evaporate residues remarkably increased, but those of COD, $NH_3^--N,\;NO_3^--N,\;NO_2^-N$, T-N decreased. 3. The values of COD, Cl, Ca, Mg, Na, hardness and evaporate residues were very high in industrial area, and those of $NH_3-N,\;NO_2^--N$, T-N were very high in commercial/residential area, and those of $NO_3^--N$ were a little high in agricultural area. 4. The correlations between depth and each value of Mg, Na, Fe, hardness and evaporate residues were highly positive, and those between DO and each value of Mg, Cu, Fe, hardness and evaporate residues were highly negative. 5. According to ANOVA analyses, the differences in three area groups (industry, commerce/residence and agriculture) on the values of $NH_3-N$, T-N, evaporate residues, hardness, Ca, Mg, K and Fe were significant at 1% level.

The D/H ratio of N2H+ in the inner envelope of YSOs

  • Baek, Giseon;Lee, Jeong-Eun
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.42 no.2
    • /
    • pp.89.3-89.3
    • /
    • 2017
  • Recent interferometric observations toward embedded protostellar systems show a clear offset between the emission peaks of N2D+ and N2H+. However, the chemical model that con-siders solely freeze-out and desorption from the dust grains could not reproduce the ob-servations. This difference between two spe-cies in the depletion zone might be caused by the reduction of the deuterated molecules, due to the reactions on grain surfaces. We present that the abundance offset between N2H+ and N2D+ can be explained if the chemi-cal model includes the surface chemistry, especially for the deuterated.

  • PDF