• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.186-196
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• 2017

In order to resolve the trimming difficulty in rotor CFD calculations, a high-efficiency and improved "delta trim method" is established to compute the blade control settings that are necessary to identify the blade motion. In this method, a simplified model which combines the blade element theory and different inflow models is employed to calculate the control settings according to the target aerodynamic forces, then it is coupled into a CFD solver with unsteady Navier-Stokes equations by the delta methodology, which makes the control settings and aerodynamics calculated and updated in the meantime at every trim cycle. Different from the previous work, the current research combines the inflow model based on prescribed wake theory. Using the method established, the control settings and aerodynamic characteristics of Helishape 7A, AH-1G and Caradonna-Tung rotors are calculated. The influence of different inflow models on trimming calculations is analyzed and the computational efficiency of the current "delta trim method" is compared with that of the "CFD-based trim method". Furthermore, for the sake of improving the calculation efficiency, a novel acceleration factor method is introduced to accelerate the trimming process. From the numerical cases, it is demonstrated that the current "delta trim method" has higher computational efficiency than "CFD-based trim method" in both hover and forward flight, and up to 70% of the amount of calculation can be saved by current "delta trim method" which turns out to be satisfactory for engineering applications. In addition, the proposed acceleration factor shows a good ability to accelerate the trim procedure, and the prescribed wake inflow model is always of better stability than other simple inflow models whether the acceleration factor is utilized in trimming calculations.

• Journal of Biomedical Engineering Research
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• v.34 no.3
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• pp.156-162
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• 2013

Moments of inertia of limb segments are essential to calculate parameters related to the segmental rotation. To analyze the human motion accurately and specifically, moments of inertia obtained from the individual are required. In this study, a simple method to determine a subject-specific moment of segmental inertia using a dynamometer is introduced. In order to evaluate the method, one male participated to test for his forearm plus hand on a commercial dynamometer. Three passive speeds, i.e. 240, 270, and $300^{\circ}/s$, were chosen to confirm whether the moment of inertia values at each speed approach to a fixed value. The same procedure was repeated on the day after to evaluate whether the method is reproducible. As the results, there were no significant differences among the speeds and between the days. The value of the moment of the forearm inertia was 0.216 $kg{\cdot}m^2$ that is apparently higher compared to values by previous models. Nonetheless, it seems to be acceptable based on our body mass index analysis using reported subject height and mass in each previous study. According to our results, the developed method could be useful to determine the segmental moment of inertia of an individual, showing no significant differences among the speeds and between the days. Thus, we believe that our results are reliable according to two appropriate evaluation procedures. This finding would be helpful to calculate segmental rotation related parameters of an individual.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.21-27
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• 2018

FRN (Full range Naphtha) is distilled from crude oil in a Naphtha Splitter Unit and is separated into the Light Straight Naphtha, Heavy Naphtha, and kerosene according to the boiling point in sequence. This separation is conducted using a series of binary-like columns. In this separation method, the energy consumed in the reboiler is used to separate the heaviest components and most of this energy is discarded as vapor condensation in the overhead cooler. In this study, the first two columns of the separation process are replaced with the Petlyuk column. A structural design was exercised by a stage to stage computation with an ideal tray efficiency in the equilibrium condition. Compared to the performance of a conventional system of 3-column model, the design outcome indicates that the procedure is simple and efficient because the composition of the liquid component in the column tray was designed to be similar to the equilibrium distillation curve. An analysis of the performance of the new process indicated an energy saving of 12.3% under same total number of trays and with a saving of the initial investment cost.

• Journal of Korean Neurosurgical Society
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• v.29 no.5
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• pp.609-614
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• 2000

Objective : A retrograde clinical study was undertaken to determine the effect of opening lamina terminalis on the development of hydrocephalus after aneurysmal subarachnoid hemorrhage(SAH). We compared the incidence ratios of the development of hydrocephalus with and without opening lamina terminalis during operation after aneurysmal SAH. Patients and Methods : From Oct. 1996 to Sep. 1998, we performed 138 aneurysm surgery for 122 patients. In 98 cases, the lamina terminalis was opened to make direct cerebrospinal fluid flow from the third ventricle to subarachnoid space for prevention of delayed hydrocephalus. We compared the incidence of hydrocephalus after opening lamina terminalis to those without opened lamina terminalis. Results : In 95 cases, the hydrocephalus was noticed in 2 cases(2.2%). It is significantly lower in the group with opening lamina terminalis than the group without opening lamina terminalis(about 10%). Conclusion : It is simple and easy procedure to open the lamina terminalis during aneurysm surgery. With this maneuver, we could reduce the incidence of hydrocephalus after aneurysmal spontaneous SAH. Thus, it is considered that the opening lamina terminalis is one of the effective methods for preventing the development of hydrocephalus after aneurysmal spontaneous SAH.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1319-1324
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• 2012

Tomatoes were harvested at different ripening stages. To determine the ripening stages, We analyzed the relation between the compound concentrations of tomato measured with HPLC and the tomato RGB images. Among the compound concentrations, tomato quality is mostly affected by the Lycopene. The $Q^2$ error of the predicted Lycopene concentration and the corresponding independent component of tomato RGB image, determined from the PLS procedure, was 0.92. and we show the effectiveness of the independent component by comparing the error between the pixel area of RGB image applied by independent component and the simple black white tomato image. This regression made it possible to construct concentration images of the tomatoes, which showed non-uniform ripening. The method can be applied in an unsupervised real time sorting machine of unripe and discolored tomato using the compound concentrations.

• Smart Structures and Systems
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• v.4 no.5
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• pp.605-628
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• 2008

In bridge structures, damage may induce an additional deflection which may naturally contain essential information about the damage. However, inverse mapping from the damage-induced deflection to the actual damage location and severity is generally complex, particularly for statically indeterminate systems. In this paper, a new load concept, called the positive-bending-inspection-load (PBIL) is proposed to construct a simple inverse mapping from the damage-induced deflection to the actual damage location. A PBIL for an inspection region is defined as a load or a system of loads which guarantees the bending moment to be positive in the inspection region. From the theoretical investigations, it was proven that the damage-induced chord-wise deflection (DI-CD) has the maximum value with the abrupt change in its slope at the damage location under a PBIL. Hence, a novel damage localization method is proposed based on the DI-CD under a PBIL. The procedure may be summarized as: (1) identification of the modal flexibility matrices from acceleration measurements, (2) design for a PBIL for an inspection region of interest in a structure, (3) calculation of the chord-wise deflections for the PBIL using the modal flexibility matrices, and (4) damage localization by finding the location with the maximum DI-CD with the abrupt change in its slope within the inspection region. Procedures from (2)-(4) can be repeated for several inspection regions to cover the whole structure complementarily. Numerical verification studies were carried out on a simply supported beam and a three-span continuous beam model. Experimental verification study was also carried out on a two-span continuous beam structure with a steel box-girder. It was found that the proposed method can identify the damage existence and damage location for small damage cases with narrow cuts at the bottom flange.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.53-58
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• 1988

KOH examination is a simple, rapid and diagnostic procedure to confirm dermatophytic infections. It is important to select a proper examination site of the lesion. To determinate the proper examination site of the lesion, mycologic studies were done with multiple specimens collected from the center, margin and out of margin of the ring-shaped dermatophytotic skin lesion on the 58 patients. The results were as follows. Positive rate of KOH wet smear was 94.8% at the center and 100% at the margin of the lesions, 22.4% at the 1cm and 5.2% at the 2cm out of the lesions. The more hyphae were found in the lesion, the more hyphae were found out of the lesion. Culture was done on the Sabouraud's glucose agar from the highest KOH positive area and the positive culture was 48 strains(82.8%) of 58 patients. These findings suggested that the ring-shaped active margin was the best site to examine mycologic studies.

• Environmental Analysis Health and Toxicology
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• v.19 no.2
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• pp.141-151
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• 2004

We exposed juvenile puffer fish, Takifugu obscurus(30 days after hatching) to various aqueous pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), 2 organotin compound.; (tributyltin ［TBT］ and triphenyltin［TPhT］) and 5 polycyclic aromatic hydrocarbon (PAH) compounds (chrysene, fluoranthene, naphthalene, phenanthrene and pyrene) to estimate median lethal concentrations (LC50s) of each pollutant after the 96-hour acute exposure. Among the inorganic metals, Hg (52 $\mu\textrm{g}$/L; 96-h LC50) was most toxic to test animals and followed by Ag (164 $\mu\textrm{g}$/L), Cu (440 $\mu\textrm{g}$/L) and Cd (1180 $\mu\textrm{g}$/L). Aqueous TBT was more toxic between the two organotins; the 96-h LC50 for TBT (5.1 $\mu\textrm{g}$/L) was 3 times lower than that of TPhT (17.3 $\mu\textrm{g}$/L). The acute toxicity of PAH compounds was highest for chrysene (1.5 $\mu\textrm{g}$/L; 96-h LC50) and decreased in the order of pyrene (65 $\mu\textrm{g}$/L) > fluoranthene (158 $\mu\textrm{g}$/L) > phenanthrene (432 $\mu\textrm{g}$/L) > naphthalene (8690 $\mu\textrm{g}$/L). The toxicity of PAH compounds wat closely related to their physico-chemical characteristics such as $K_{ow}$ and water solubility, and well explained by simple QSAR relationship. The sensitivity of puffer fish to various inorganic and organic pollutants was generally comparable to various fish species widely used as standard test species in previous studies and further evaluation should be conducted to develop adequate testing procedure for T. obscurus when used in various toxicity tests.

• The Korean Journal of Pharmacology
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• v.1 no.1 s.1
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• pp.47-52
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• 1965

There are several methods used for screening and evaluating anti -inflammatory agents. Among these, 'Granuloma pouch' technic introduced by Hans Selye is considered as a simple and reliable method. The procedure of 'Granuloma pouch' technic is as follows: Rats were used as experimental animals. An air pocket was produced in the subcutaneous tissue of the mid-dorsal portion between the shoulders by the injection of 25ml of the air which was immediately followed by injection of 1 ml of 1% croton oil as irritant. Inflammatory exudate accumulated in the pouch during the succeeding 14 days. After sacrificing the rats on the last day of the experiment, the amount of the exudate in the pouch and the weight of the granuloma tissue was measured. The author observed and compared the anti-inflammatory activities of the several steroid compounds when they are given by different methods. 1. In the control rats, the amount of inflammatory fluid and the weight of the granuloma tissue after 14 days were 9ml and 3gm respectively. 2. Injection of hydrocortisone 1.5mg subcutanenusly, 24 hours prior to pouch formation into the area where the pouch is to be formed, successfully prevented the inflammatory processes. 3. Injection of hydrocortisone 1.5mg in the air pocket formed 24 hours prior to croton oil injection was ineffective. 4. Injection of hydrocortisone into the pouch at a distance of 5mm apart from the pouch formation did not prevent the development of inflammation. 5. Anti-inflammatory activities of hydrocortisone administered systematically(injected intramuscularly into the area which is not related to the area of pouch formation) for 10 days were proportional to the doses of hydrocortisone administered. 6. DOCA, testosterone, and progesterone did not show the anti-inflammatory activity.

• Journal of Korean Neurosurgical Society
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• v.40 no.3
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• pp.180-185
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• 2006

Objective : Middle cerebral artery occlusion[MCAO] has widely been used to produce ischemic brain lesions. The lesions induced by MCAO tend to be variable in size because of the variance in the collateral blood supply found in the mouse brain. To establish a less invasive and reproducible focal ischemia model in mice, we modified the technique used for rat photo thrombosis model. Methods : Male C57BL/6 mice were subjected to focal cerebral ischemia by photothrombosis of cortical microvessels. Cerebral infarction was produced by intraperitoneal injection of Rose Bengal, a photosensitive dye and by focal illumination through the skull. Motor impairment was assessed by the accelerating rotarod and staircase tests. The brain was perfusion-fixed for histological determination of infarct volume four weeks after stroke. Results : The lesion was located in the frontal and parietal cortex and the underlying white matter was partly affected. A relatively constant infarct volume was achieved one month after photothrombosis. The presence of the photothrombotic lesion was associated with severe impairment of the motor performance measured by the rotarod and staircase tests. Conclusion : Photothrombotic infarction in mice is highly reproducible in size and location. This procedure can provide a simple method to produce cerebral infarction in a unilateral motor cortex lesion. In addition, it can provide a suitable model for study of potential neuroprotective and therapeutic agents in human stroke.