• Journal of Environmental Science International
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• v.22 no.2
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• pp.251-257
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• 2013

Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. It makes high quality discharge data, they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and exprerimental research data from measurement are not enough. ADCP(Acoustic Doppler Current Profiler) have been introduced and utilized for flow measurements since the end of 1980's. ADCP flow method is a formal method for flow measurement can easily applyd to relatively large rivers gradually recognized. This equipment can measure the non-contact three-dimensional velocity and water depth data very quickly and efficiently. Also, spatial and temporal resolution of the data is more accurate than any other flow measurement methods which measure flow rate by velocity - area measurement method. In this paper, the velocity is measured using various flow meter and verified the effectiveness by applying from the ADCP in Geum-river. Various flow meters which are med for discharge measurements are VALEPORT002, FLOW TRACKER, PRICE AA and ADCP. The average of five times flow measurement result by ADCP was $10.412m^3/s$, with a standard deviation of 0.68. The repeat test by ADCP and comparison between ADCP and other flow devices to verify the most import factor, flow measurement accuracy. In the result, repeat test of the ADCP showed similar values, flow values were similar to other velocity device results and the average error is 7.7%.

• Journal of Korean Neurosurgical Society
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• v.40 no.6
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• pp.434-440
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• 2006

Objective : The purpose of this study is to examine the influence of cranioplasty on dynamics of cerebral blood flow[CBF] and cerebrovascular reserve capacity[CVRC], and to investigate the usefulness of single photon emission computed tomography [SPECT] as a prognostic factor for neurological improvement after cranioplasty. Methods : Between March 2003 and December 2005, a prospective study was performed on 24 patients who had undergone total 25 cranioplasty operations. Cerebral blood flow velocities in the middle cerebral artery[MCA] and internal carotid artery[ICA] were obtained by transcranial Doppler ultrasonography[TCD]. The CVRC was assessed by SPECT in the natural state and after stimulation with 1g of acetazolamide. Neurological improvement after cranioplasty was compared between patients who showed hyperactivity to acetazolamide-activated SPECT [Group 1, n=7] and hypoactivity to acetazolamide-activated SPECT [Group 2, n=17]. These measurements were obtained two weeks prior to and two weeks after cranioplasty. Results : The blood flow velocities at the opposite site to the cranioplasty as well as at the cranioplasty site were significantly increased [P<0.05]. Compared with Group 2, there was significant increase in CBF and neurological improvement after cranioplasty in Group 1. Conclusion : Among patients with surgical bony defects, the patients who had normal reactivity of the CVRC showed a significant increase in CBF and neurological improvement after cranioplasty. The authors suggest that CVRC measurement prior to surgery may be an important prognostic factor for neurological improvement after cranioplasty.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.442-448
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• 2009

To evaluate the combustion mechanism of each droplet cluster downstream of the premixed spray flame, the simultaneous time-series measurements were conducted by using optical measurement system consisting of laser tomography, multi-color integrated Cassegrain receiving optics (MICRO) and phase Doppler anemometer (PDA). Furthermore, the group combustion number of droplet cluster was estimated experimentally, and the combustion mechanism of droplet cluster was examined applying the theoretical analysis. The group combustion number, $G_c$, was experimentally estimated about all droplet cluster verified by planar images, and it was classified into the internal group combustion mode and the external group combustion mode according to the theoretical analysis. It is found that there are cases in which the group combustion number estimated experimentally for droplet cluster agree or disagree with the classification by theoretical analysis. The reason of disagreement is considered due to that the group combustion number was only estimated by the geometrical arrangement of droplets in cluster, and that the actual phenomenon is three-dimensional but the measurement system is two-dimensional.

• Journal of ILASS-Korea
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• v.6 no.1
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• pp.18-24
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• 2001

Liquid fossil fuel contaminated by water can cause trouble in the combustion processes and affect the endurance of a combustion system. Using an optical sensor to monitor the water content instantaneously in a fuel pipeline is an effective means of controlling the fuel quality in a combustion system. In two component liquid flows of oil and water, the flow pattern and characteristics of water droplets are changed with various flow conditions. Additionally, the light scattering of the optical sensor measuring the water content is also dependent on the flow patterns and droplet characteristics. Therefore, it is important to investigate the detailed behavior of water droplets in the pipeline of the fuel transportation system. In this study, the flow patterns and characteristics of water droplets in the turbulent pipe flow of two component liquids of gasoline and water were investigated using optical measurements. The dispersion of water droplets in the gasoline flow was visualized, and the size and velocity distributions of water droplets were simultaneously measured by the phase Doppler technique. The Reynolds number of the gasoline pipe flow varied in the range of $4{\times}10^{4}\;to\;1{\times}10^{3}$, and the water content varied in the range of 50 ppm to 300 ppm. The water droplets were spherical and dispersed homogeneously in all variables of this experiment. The velocity of water droplets was not dependent on the droplet size and the mean velocity of droplets was equal to that of the gasoline flow. The mean diameter of water droplets decreased and the number density increased with the Reynolds number of the gasoline flow.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.9-14
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• 2007

To illusσ'ate the variation of current around artificial upwelling structure which is located in the South sea of Korea, current measurements using ADCP (Acoustic Doppler Current Profiler) during neap and spring tides were carried out on 27th July(summer)， 14th October and 30th November(Autumn), 2006. Current after the set up of artificial upwelling structure were shown different in the upper and lower layer, the boundary between the upper and lower layer was at $27{\sim}30m$ depth in summer. And the boundary layer was formed structure of three layer in Autumn. Upwelling and downwelling flow were occurred around the seamount， and these vertical flows were connected from surface to bottom The distribution of vertical shear and relative vorticity support the vertical flow around the seamount. The strength of vertical shear was higher and the direction of relative vorticity was anticlockwise (+) around the upwelling area.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.473-485
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• 1997

Detailed experimental study has been made of air blast kerosene spray flames with and without swirl in combustion air flow. Phase-Doppler detect technique is used to measure Sauter mean diameter, axial component mean and rms velocity, size-velocity correlation, and number density. These measurements are obtained for both nonreacting and reacting cases under several stable flame conditions. The results show that the introduction of swirl to the combustion air modifies the spatial distribution of droplet size, velocity, and number density, and thus alters the flame structure. However, due to the weak swirl intensity, the overall structure of swirling flames are essentially same as that of nonswirling flames. Physical model of structure of air blast atomized spray flames is projected to show that spray flames are composed of three distinct regions: the two-phase mixture region, the main reaction and the intermittent combustion region. Near the atomizer, two phase mixture of droplet and air is formed in the core region. This dense spray region is characterized by high droplet number density and the strong convective effect. There follows the main combustion region where the main flame penetrates within the spray boundary. Main reaction region of these flames are governed by internal group combustion mode. Finally there exists the intermittent combustion region where local group burning or isolated droplet burning occurs.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.289-295
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• 2013

Objective : Cerebral vasospasm is a common and potentially devastating complication of aneurysmal subarachnoid hemorrhage (aSAH). Inflammatory processes seem to play a major role in the pathogenesis of vasospasm. C-reactive protein (CRP) constitutes a highly sensitive inflammatory marker. Elevation of serum CRP levels has been demonstrated in patients with aSAH. The purpose of the current study was to evaluate the possible relationship between CRP levels in the serum and transcranial Doppler (TCD) and the development of vasospasm in patients with aSAH. Methods : A total of 61 adult patients in whom aSAH was diagnosed were included in the study from November 2008 to May 2011. The patients' demographics, Hunt and Hess grade, Fisher grade, CT scans, digital subtraction angiography studies, and daily neurological examinations were recorded. Serial serum CRP measurements were obtained on days 1, 3, 5, 7, 9, 11 and 13 and TCD was measured on days 3, 5, 7, 9, 11 and 13. All patients underwent either surgical or endovascular treatment within 24 hours of their hemorrhagic attacks. Results : Serum CRP levels peaked on the 3rd postoperative day. There were significant differences between the vasospasm group and the non-vasospasm group on the 1st, 3rd and 5th day. There were significant differences between the vasospasm group and the non-vasospasm group on the 3rd day in the mean middle cerebral artery velocities on TCD. Conclusion : Patients with high levels of CRP on the 1st postoperative day and high velocity of mean TCD on the 3rd postoperative day may require closer observation to monitor for the development of vasospasm.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.577-583
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• 2014

A ship-to-ship (STS) lightering operation takes place in order to transfer cargo (e.g. crude oil or petroleum products) between an ocean-going ship and a service ship alongside it. Instrumental measurements to accurately determine the relative speeds and distances during the approach between the vessels would benefit the operational safety and efficiency. A velocity information GPS (VI-GPS) system, which uses the instantaneous velocity measures from carrier-phase Doppler measurement, has been applied in a field observation onboard a service ship (Aframax tanker) approaching a ship-to-be-lightered (VLCC) in open waters. This article proposes to apply VI-GPS as the input sensor to a guidance and decision-support system aiming to provide accurate velocity information to the officer in charge of an STS operation. A method for precise velocity measurement using VI-GPS was described and the measurement results were compared each other with the results of Voyage Data Recorder (VDR) and VI-GPS that showed the concept of a guidance and decision-support system applying VI-GPS with the field test results during STS operations. Also, it turned out that VI-GPS has sufficient accuracy to serve as an input sensor from the field test results.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.832-837
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• 1999

lntrarenal resistive index (RI) was determined in normal, sedated and diuretic kidneys. The mean RI values of normal dogs were $0.64{\pm}0.03$ without statistically significant difference between left and right kidney. Interrenal RI difference (${\Delta}RI$) was $0.03{\pm}0.01$. No significant relationship was found between mean intrarenal RI versus body weight. The mean intrarenal RI values after administration of acepromazine, xylazine, thiopental, and ketamine were $0.66{\pm}0.03$, $0.64{\pm}0.03$, $0.56{\pm}0.05$, and $0.50{\pm}0.05$, respectively. After administration of acepromazine or xylazine, a significant change of the RI was not found. But, a significant decrease of the RI following thiopental or ketamine administration could be observed as compared with the normal RI. The mean intrarenal RI values were $0.63{\pm}0.06$ and $0.62{\pm}0.04$ at 10 minutes and 30 minutes after injection of furosemide, respectively. No significant change of intrarenal RI was found after administration of furosemide. But, mannitol significantly decreased mean intrarenal RI to $0.57{\pm}0.02$ and $0.58{\pm}0.03$ at 30 minutes and 60 minutes, respectively. Based on the obtained results, values of 0.72 and 0.05 may be proposed as the reasonable upper limits of RI and ${\Delta}RI$ of normal average. Acepromazine or xylazine are recommended as anesthetics for renal diseases because they have less effect on the RI. Further study using mannitol injection to increase ${\Delta}RI$ may be suggested in unilateral urinary tract obstruction since mannitol more effectively changed mean RI than furosemide.

• Imaging Science in Dentistry
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• v.48 no.3
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• pp.153-160
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• 2018

Purpose: This study aimed to assess the reliability of ultrasonography (US) in comparison with cone-beam computed tomography (CBCT) as a tool for monitoring the healing of jaw lesions. Materials and Methods: Twenty-one radiolucent lesions in jaws referred to the Oral Surgery Department at our institution were selected for this study. All lesions underwent CBCT and US examinations. The anteroposterior, superoinferior, and mesiodistal dimensions of the lesions were measured on CBCT and US images before surgery and at 6 months after surgery. The dimensions were compared between the US and CBCT images. Blood-flow velocity around the lesions was measured by color Doppler before surgery and at 1 week and 6 months after surgery to assess the capability of US to show changes in blood-flow velocity around the lesion. Results: Before surgery, there were no significant differences between US and CBCT in the mesiodistal and anteroposterior dimensions, although a significant difference was found in the superoinferior dimension (P<.05). However, at 6 months after surgery, significant differences were found between US and CBCT in all dimensions, and it is likely that the US measurements more accurately reflected the extent of healing. The average blood-flow velocity increased at 1 week after surgery (5.84 cm/s) compared with the velocity before surgery (4 cm/s) (P<.05). Then, at 6 months after surgery, the blood-flow velocity significantly decreased (3.53 cm/s) compared to the velocity measured at 1 week after surgery (P<.05). Conclusion: US with color Doppler was confirmed to be a more efficient tool than CBCT for monitoring bone healing.