• Journal of Life Science
• /
• v.9 no.2
• /
• pp.76-81
• /
• 1999

216 microorganisms which able to degrade wasted lubricant were isolated in the region of contaminated with wated lubricant such automobile repair shops, garages and gas stations in Taejon. Most activated strain among them is selected and used in this research. The microorganism in identified as Acinetobacter lwoffii 16C-1, which shows active growth and hydrocargon utilization withnormal alkane such as tetradecane, hexadecane and octadecane, and do not grow aromatic hydrocargons, cycloalkane, and branched alkane. In addition, A. lwoffii 16C-1 has resistance to heavy metals such as Ba, Li, Cr, and Mn more than 6.4mg/ml, and showed negligible tolerance against antibiotics. Effects of environmental conditions including concentration of wasted lubricnt, pH, NaCl concentration, nitrogen source and phosphate on microorganism growth and emulsification were studied. 2% of wasted lubricant, pH 7.0, 0-1% of NaCl, 0.2% of peptone, and 0.01% of K2HPO4 is turn out to be optimum condition. By the analysis of remaining oils, almost of hydrocarbons added to the media are removed by A. lwoffii 16C-1 at 30$^{\circ}C$ after 2 days of culture, which showed excellent oil degradation characteristics.

• Steel and Composite Structures
• /
• v.17 no.3
• /
• pp.271-285
• /
• 2014

This paper aims to examine the behavior of slender reinforced concrete columns confined with external glass fiber reinforced polymers (GFRP) sheets under eccentric loads. The experimental work conducted in this paper is an extension to previous work by the author concerning the behavior of eccentrically loaded short columns strengthened with GFRP wrapping. In this study, nine reinforced concrete columns divided into three groups were casted and tested. Three eccentricity ratios corresponding to e/t = 0, 0.10, and 0.50 in one direction of the column were tested in each group. The first group was the control one without confinement with slenderness ratio equal 20. The second group was the same as the first group but fully wrapped with one layer of GFRP laminates. The third group was also fully wrapped with one layer of GFRP laminates but having slenderness ratio equal 15. The experimental results of another two groups from the previous work were used in this study to investigate the difference between short and slender columns. The first was control one with slenderness ratio equal 10 and the second was fully wrapped and having the same slenderness ratio. All specimens were loaded until failure. The ultimate load, axial deformation, strain in steel bars, and failure mechanisms of each specimen were generated and analyzed. The results show that GFRP laminates confining system is less effective with slender columns compared with short one, but this solution is still applied and it can be efficiently utilized especially for slender columns with low eccentric ratio.

• Advances in Computational Design
• /
• v.5 no.4
• /
• pp.397-416
• /
• 2020

Functionally graded material (FGM) illustrates a novel class of composites that consists of a graded pattern of material composition. FGM is engineered to have a continuously varying spatial composition profile. Current work focused on buckling analysis of beam made of stepwise linear and quadratic graded material in axial direction subjected to axial span-load with piecewise function and rested on shear layer based on classical beam theory. The various boundary and natural conditions including simply supported (S-S), pinned - clamped (P-C), axial hinge - pinned (AH-P), axial hinge - clamped (AH-C), pinned - shear hinge (P-SHH), pinned - shear force released (P-SHR), axial hinge - shear force released (AH-SHR) and axial hinge - shear hinge (AH-SHH) are considered. To the best of the author's knowledge, buckling behavior of this kind of Euler-Bernoulli beams has not been studied yet. The equilibrium differential equation is derived by minimizing total potential energy via variational calculus and solved analytically. The boundary conditions, natural conditions and deformation continuity at concentrated load insertion point are expressed in matrix form and nontrivial solution is employed to calculate first buckling loads and corresponding mode shapes. By increasing truncation order, the relative error reduction and convergence of solution are observed. Fast convergence and good compatibility with various conditions are advantages of the proposed method. A MATLAB code is provided in appendix to employ the numerical procedure based on proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.5
• /
• pp.94-102
• /
• 2003

This paper presents active management of feeder automation systems using active database. DAS(Distribution Automation System) has been managed for feeder automation in passive manner. Therefore, feeder automation system has to be managed by operator when feeder overloadings is detected. It may be possible for propagating the feeder overloadings area by operator's mistake. To overcome this defect, the author proposed the feeder automation technique with active manner to obtain feasible feeder reconfiguration. Active database can manage feeder automation system by data driven monitoring of events and by corresponding actions without operator's intervening. To manage feeder automation system with active manner, production rule, active rule manager are designed. And active database system architecture for feeder automation system is proposed. Test results on the KEPCO's 108 bus distribution system show that the performance is efficient and robust.

• The Journal of Korean Medicine
• /
• v.17 no.2 s.32
• /
• pp.251-263
• /
• 1996

In order to investigate experimentally that effect of Moschus, Bovis Calculus, Ursi Fel aqua-axupuncture on acutely damaged liver of rats induced by radix aconiti. The author admininisterated aqua-acupuncture according to method of manufacture stimulation to corresponding points, Kan-su$(BL_8)$ and Ki-mun($LR_{14}$), and carried out hematological, serological examination and electromicroscopical obseration. WBC level was decreased significantly in the experimental groups at 24 and 48 hours as compared with the control group. ${\gamma}-GTP$ level was decreased significantly in the experimental groups at 24 and 48 hours as compared with the control group. GPT level was decreased significantly in the experimental groups at 24 and 96 hours as compared with the control group, but GOT level did not reeveal any statistical difference. At 24-hours group, the cell organelles of the hepatic cells are destructed. The cisternae of the smooth endoplasmic reticulum are particulary dilated in the 24-hours control group compared with experimental group. At 48-hours group, the destructed cell organelles are recovered in the experimental group compared with control group. At 96-hours group, the cell organelles of hepatic cells are showing feture of normal group. According to the above findings, it is considered that Moschus, Bovis Calculus, Ursi Fel aqua-acupuncture has effects of recovery of acutely damaged liver.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1991.10a
• /
• pp.357-365
• /
• 1991

Military material-supply problem is one of the most important logistic problems under conscription system. Formally, two approaches were followed lowed to this problem. (1) Needs for material per soldier is estimated by past experience. The total demand for the material is estimated by multiplication of this coefficient and the number of soldiers given in the governmental programme. (2) The total demand for the material is estimated by the forcast based on the past statistics. The material supply system based on these estimates, however, relies too much on past statistics ;lack of flexibility is feared to adapt itself to changes in conscription programme, life-time of materials and so on. In this paper, the author has followed new approach : The conscription system itself is a linear input-output system, in which sequences of enlistment and dischargement are regarded as input and output. And the sequencial demands for the material are related by another linear transformation to the former sequences. In this regard z-transformation is applied to construct to transfer functions associated with this system. With these transfer functions, methods are established to determine the material demand corresponding to conscription programme and life-time distribution. Numerical methods by computers are also prepared.

• Journal of Pharmacopuncture
• /
• v.1 no.1
• /
• pp.22-34
• /
• 1997

In order to investigate experimentally that effect of Moschus, Bovis Calculus, Ursi Fel aqua-acupuncture on acutely damaged liver of rats induced by radix aconiti, the author gave Moschus, Bovis Calculus, Ursi Fel aqua-acupuncture according to method of manufacture stimulation to corresponding points, Kan-su (B18) and Ki-mun (Liv14), and carried out hematological, serological examination and electromicroscopical observation. The following results were obstained : 1. At 6 hours, cell organelles induced by radix aconiti toxicity prominently destructed in control and aqua-acupuncture treatment groups. 2. At 12 hours, cell organelles, destruction was some similarities between control group and aqua-acupuncture treatment group. 3. At 24 hours, rough endoplasmic reticulum and Golgi complex comparatively developed in aqua-acupuncture group treatment as compared with control group. 4. At 48 hours, cell organelles, destruction was recovered in aqua-acupuncture treatment group as compared with the control group and it was similiar normal findings. According to the above findings, it is considered that Moschus, Bovis Calculus, Ursi Fel aqua-acupuncture has effects of recovery of acutely damaged liver.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.1
• /
• pp.158-161
• /
• 2004

Scenedesmus spp. were cultured for 51 days in newly developed medium, KEP I (Kim and Ecopeace: initials of corresponding author and environmental company) made with Bacterio-Mineral-Water (3%, v/v) that had been bio-reacted with swine urine medium to 10% (v/v) Bold's Basal medium, and investigated for cancer chemopreventive potential by measuring the induction of quinone reductase (QR), glutathione S-transferase (GST), and reduced glutathione (GSH), and inhibition of cytochrome P450 (CYP) 1A1 activity. The activitives of QR and GST of Scenedesmus spp. cultured in KEP I medium were increased by 3.0-fold and 1.5-fold, respectively. However, Scenedesmus spp. cultured in control medium (CT) increased the activitives of QR and GST by 1.8-fold and 1.3-fold, respectively. Scenedesmus spp. in KEP I medium strongly inhibited CYP 1Al activity. These results show that Scenedesmus spp. in KEP I medium has cancer chemopreventive potential and may be a candidate for further development as a chemopreventive agent.

• Sleep Medicine and Psychophysiology
• /
• v.2 no.2
• /
• pp.133-137
• /
• 1995

The author reviews current knowledge about what REM sleep is and where and how it is generated. REM sleep is the state in which our most vivid dreams occur. REM sleep is identified by the simultaneous presence of a desynchronized cortical EEG, an absence of activity in the antigravity muscles(atonia), and periodic bursts of rapid eye movements. Another characteristic phenomena of REM sleep are the highly synchronized hippocampal EEG of theta frequency and the ponto-geniculo-occipital(PGO) spike. All these phenomena can be explained in terms of changes in neuronal activity. Transection studies have determined that the pons is sufficient for generating REM sleep. Lesion studies have identified a small region in the lateral pontine tegmentum corresponding to lateral portions of the nucleus reticularis pontis oralis(RPO) and the region immediately ventral to the locus coeruleus, which is required for REM sleep. Unit recording studies have found a population of cells within this region that is selectively active in REM sleep. Cholinergic neurons of the giant cell field of pontine tegmentum(ETG), which is 'REM a sleep-on cells', has shown to be critically involved in the generation of REM sleep. Noradrenergic neurons of the locus coeruleus and serotonergic neurons of the dorsal raphe, which are called 'REM sleep-off cells', appear to act in a reciprocal manner to the cholinergic neurons. It is proposed that the periodic cessations of discharge of 'REM sleep-off cells' during REM sleep might be significant for the prevention of the desensitization of receptors of these neurons.

• Structural Engineering and Mechanics
• /
• v.57 no.2
• /
• pp.239-263
• /
• 2016

The paper studies the natural oscillation of the three-layered solid sphere with a middle layer made of Functionally Graded Material (FGM). It is assumed that the materials of the core and outer layer of the sphere are homogeneous and isotropic elastic. The three-dimensional exact equations and relations of linear elastodynamics are employed for the investigations. The discrete-analytical method proposed by the first author in his earlier works is applied for solution of the corresponding eigenvalue problem. It is assumed that the modulus of elasticity, Poisson's ratio and density of the middle-layer material vary continuously through the inward radial direction according to power law distribution. Numerical results on the natural frequencies related to the torsional and spheroidal oscillation modes are presented and discussed. In particular, it is established that the increase of the modulus of elasticity (mass density) in the inward radial direction causes an increase (a decrease) in the values of the natural frequencies.