• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.6
• /
• pp.1324-1329
• /
• 2001

The depression of the external situation like the departure of WTO system and the plan of EEZ proclaim is forcing fishery into improving their fishing condition. By this international and domestic circumstance, development of the sea water cooling apparatus for fish hold storage is demanded sincerely. This study represents the thermal characteristics of the fish hold storage during transportation. The numerical analysis in this study is the finite volume method with the SIMPLE computational algorithm to study the seawater flow behavior in the fish hold storage. The computation were carried out with the variations of the circulating flow velocity and depth of fish hold storage. As the result of the three dimensional simulations, the mean temperature doesn't almost change by the circulating flow rate. find the mean temperature is suddenly changed by the ratio of depth of fish hold storage.

• Tribology and Lubricants
• /
• v.20 no.2
• /
• pp.91-96
• /
• 2004

Wear behavior of self-mated stainless steels in NaCl solution has been investigated. The experiment was done in the corrosive liquid of which NaCl concentration of $0\~3\%$ and temperature of $15\~90^{\circ}C$. Two kinds of wear type were observed: one is 'severe wear' type which shows gradually increasing wear volume with increasing sliding distances, the other is 'mild wear' type which shows change of wear rate from high value to low at transition distance. The specific wear rate in severe wear type was not sensitive to the liquid temperature and concentration of NaCl but stable at value of $1\times10^{-3}\;mm^3$ approximately.

• Solar Energy
• /
• v.10 no.1
• /
• pp.38-46
• /
• 1990

For the optimal design and the efficient operation of the double pipe type latent heat storage equipment, the effect of the parameters of the system were analysed. The statistical analysis showed that the theoretical and the experimental results of the volume change rate and the temperature variations were well agreed. Therefore, this theoretical model is reasonable to analyze two dimensional moving boundary problems. In the analysis of the effects of the parameters, the heat extraction fraction and the water outlet temperature of the system as function of the time were analysed depending on the initial temperature of PCM, water inlet temperature, water mass flow rate and the dimension of the inner tube.

• Journal of Mechanical Science and Technology
• /
• v.17 no.7
• /
• pp.1083-1094
• /
• 2003

This study represents an assessment of the phase-Doppler technique to the measurements of dense droplet laden jet. High-pressure injection fuel sprays have been investigated to evaluate the use of the Phase-Doppler anemometry (PDA) technique. The critical issue is the stability of the phase-Doppler anemometry technique for dense droplet laden jet such as Diesel fuel spray in order to insure the results from the drop size and velocity measurements are repeatable, consistent, and physically realistic because the validation rate of experimental data is very low due to the thick optical density. The effect of shift frequency is minor, however, the photomultiplier tube (PMT) voltage setting is very sensitive to the data acquisition and noise in dense droplet laden jet. The optimum PMT voltage and shift frequency should be chosen so that the data such as volume flux and drop diameter do not change rapidly.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.39 no.6
• /
• pp.274-282
• /
• 2013

Objectives: The posterior maxillary region often provides a limited bone volume for dental implants. Maxillary sinus elevation via inserting a bone graft through a window opened in the lateral sinus wall has become the most common surgical procedure for increasing the alveolar bone height in place of dental implants in the posterior maxillary region. The purpose of this article is to assess the change of bone volume and the clinical effects of dental implant placement in sites with maxillary sinus floor elevation and autogenous bone graft through the lateral window approach. Materials and Methods: In this article, the analysis data were collected from 64 dental implants that were placed in 24 patients with 29 lacks of the bone volume posterior maxillary region from June 2004 to April 2011, at the Department of Oral and Maxillofacial Surgery, Inha University Hospital. Panoramic views were taken before the surgery, after the surgery, 6 months after the surgery, and at the time of the final follow-up. The influence of the factors on the grafted bone material resorption rate was evaluated according to the patient characteristics (age and gender), graft material, implant installation stage, implant size, implant placement region, local infection, surgical complication, and residual alveolar bone height. Results: The bone graft resorption rate of male patients at the final follow-up was significantly higher than the rate of female patients. The single autogenous bone-grafted site was significantly more resorbed than the autogenous bone combined with the Bio-Oss grafted site. The implant installation stage and residual alveolar height showed a significant correlation with the resorption rate of maxillary sinus bone graft material. The success rate and survival rate of the implant were 92.2% and 100%, respectively. Conclusion: Maxillary sinus elevation procedure with autogenous bone graft or autogenous bone in combination with Bio-Oss is a predictable treatment method for implant rehabilitation.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.26 no.2
• /
• pp.59-68
• /
• 1984

The Purpose of this study was to investigate the effect of the change in misture content on some physical properties of grains, and some relations amont the properties. Materials included ere rough rice, brown rice, barley and wheat with the range of moisture content of 6~26 percent, 7~25 percent, 10~24 percent and 6~22 percent, respectively. Kernel dimension, sphericity, kernel weight, and volume were included as the physical properties of the grains. The results obtained are summarized as follows; 1. The ratio of grain length to the thickness was in the range of 3.59~4.16 for rough rice(Indica type), 2.98~3.27 for rough rice(Japonica type), 3.25 for brown rice (I.T.), 2.14~2.38 for brown rice(J.T.), 2.92~3.13 for barley and 2.10~2.21 for wheat, respectively. 2. The sphericity was found to be 42 percent for rough rice(I.T.), 48 percent for rough rice(J.T.), 52 percent for brown rice(I.T.), 62 percent for brown rice(J.T.), 45 percent for barley and 61 percent for wheat, respectively. 3. The kernel weight of grains was linealy increased with the increase of moisture content. At a specified moisture centent of 14 percent, the kernel weight was shown to be in the range of 4.72${\times}10^{-5}$~3.58${\times}10^{-5}$kg for wheat, 3.60${\times}10^{-5}$~3.12${\times}10^{-5}$kg for barley, 2.80${\times}10^{-5}$~2.35${\times}10^{-5}$kg for rough rice, and 2.24${\times}10^{-5}$~1.82${\times}10^{-5}$kg for brown rice, respectively. 4. The kernel volume was linearly increased with increase of moisture content. The rate of increase was significantly low for rough rice in comparison with the remaining grains. The kernel volume, at a specified moisture content of 14 percent, was in the range of 3.51${\times}10^{-8}$~2.76${\times}10^{-8}m^3$ for wheat, 2.84${\times}10^{-8}$~2.43${\times}10^{-8}m^3$ for barley, 2.93${\times}10^{-8}$~1.97${\times}10^{-8}m^3$ for rough rice, and 1.61${\times}10^{-8}$~1.29${\times}10^{-8}m^3$ for brown rice, respectively. 5. The kernel volume of grains was found to be related to the length, width, thickness and kernel weight as a exponential function. The kernel volume was shown to have correlation coefficient to the length factor rough rice and barley which were of low sphericity, while the width factor was predominant for brown rice and wheat which was of high sphericity.

• Transactions of Materials Processing
• /
• v.22 no.8
• /
• pp.450-455
• /
• 2013

In the current study, a new dynamic recrystallization model for predicting high temperature flow stress is developed based on a physical model and the mean field theory. In the model, the grain aggregate is assumed as a representative volume element to describe dynamic recrystallization. The flow stress and microstructure during dynamic recrystallization were calculated using three sub-models for work hardening, for nucleation and for growth. In the case of work hardening, a single parameter dislocation density model was used to calculate change of dislocation density and stress in the grains. For modeling nucleation, the nucleation criterion developed was based on the grain boundary bulge mechanism and a constant nucleation rate was assumed. Conventional rate theory was used for describing growth. The flow stress behavior of pure copper was investigated using the model and compared with experimental findings. Simulated results by cellular automata were used for validating the model.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.12 no.2
• /
• pp.53-66
• /
• 1999

This study has been carried out to investigate the effects of Dojuksan on the renal functions and internal secretion system, as water balance, urine volume, urinary excretion of sodium and potassium, free water clearance, urinary excretion of creatinine, plasma levels of artrial natriuretic peptide (ANP), plasma levels of aldosterone and plasma renin activity, comparing experimental group which Dojuksan water extract were administrated with control group. Sprague-Dawley rats, about 200-250 g, were used for this experiment. The results of this study were as follows: 1. Water balance decreased significantly after the administration of Dojuksan water extract. 2. Urine volume increased significantly after the administration of $100{\mu}l$ Dojuksan water extract per 100g rat. 3. Urinary excretion of sodium increased significantly but urinary excretion of potassium did not change after the administration of Dojuksan water extract. 4. Free water clearance decreased significantly after the administration of Dojuksan water extract 5. Urinary excretion of creatinine increased significantly after the administration of Dojuksan water extract 6. Plasma renin activity did not change after the administration of Dojuksan water extract 7. Plasma levels of artrial natriuretic peptide (ANP) did not change after the administration of Dojuksan water extract 8. Plasma levels of aldosterone decreased significantly after the administration of 200 ${\mu}Dojuksan water extract per l00g rat The results suggest that Dojuksan increase the urinary excretion of sodium. and thus reduce the water balance, which resulted from suppression of sodium reabsorption into renal tubule by increasing glomerular filtration rate and decreasing aldosterone.

• Computers and Concrete
• /
• v.33 no.5
• /
• pp.559-572
• /
• 2024

Problems of under-sized dams (small dams with large basin area) could get worse under the global warming condition. This study evaluates the possible change of these problems with the Namgang Dam, an under-sized dam in Korea. For this purpose, first, this study simulates the dam inflow data using a rainfall-runoff model, which are then used as input for the reservoir operation. As a result, daily dam storage, dam release, and dam water supply are derived and compared for both past observed period (1973~2022) and future simulated period (2006~2099) based on the global warming scenarios. Summarizing the results are as follows. First, the inflow rate in the future is expected to be increased significantly. The maximum inflow could be twice of that observed in the past. As a result, it is also expected that the frequency of the water level reaching the high level is increasing. Also, the amount and frequency of dam release are to be increased in the future period. More seriously, this increase is expected to be concentrated on rather extreme cases with large dam release volume. Simply, the condition for flood protection in the downstream of the Namgang Dam is becoming worse and worse. Ironically, the severity of water shortage problem is also expected to become much worse. As the most extreme case, the frequency of no water supply was zero in the observed period, but in the future period, it becomes once every five years. Both the maximum consecutive shortage days and the total shortage volume are expected to become more than twice in the future period. To prevent or mitigate this coming problem of an under-sized dam, the only countermeasure at this moment seems to be its redevelopment. Simply a bigger dam with larger dam reservoir can handle this adverse effect more easily.

• Journal of radiological science and technology
• /
• v.42 no.6
• /
• pp.435-440
• /
• 2019

This is to study the accuracy of the actual size according to the TOD(table object distance; TOD) change when measuring blood vessels using angiography equipment, and to help the optimal selection of the device used accordingly. Balls similar to the size of common vessels were calibrated with TOD using 30 mm, 20 mm, 10 mm, 5 mm and acrylic phantoms, catheter calibration from 0 cm to 10 cm, 20 cm and 30 cm, respectively. It was measured whether there was a change in the measured value according to the change. The equipment used was GE Innova 3131 IQ equipment, and the image reconstruction method was GE AW4.7 post processing program. Two radiotechnologists were scanned three times by catheter calibration method and 3DRA(3dimension rotational angiography; 3DRA) volume rendering method. The independent sample T-test showed 0.981 (p> 0.05) to verify the significance between the two observers. As a result, in case of catheter calibration, the error rate at TOD 0 mm and 10 mm is within ± 10%, but when the TOD is changed to 20 mm and 50 mm respectively, the tolerance is ± 10% except for 30 mm ball exceeded. On the other hand, 3DRA was included within the tolerance range of ± 10% overall even when the TOD was changed from 0 mm to 50 mm. In the catheter calibration method, the larger the TOD, the larger the error range, and the 3DRA method was able to measure vascular vessels accurately close to the actual measurement without any consideration of the TOD.