• Journal of Soil and Groundwater Environment
• /
• v.6 no.2
• /
• pp.69-81
• /
• 2001

The constitutive relation among capillary pressure, saturation and relative permeability should be predetermined in order to simulate immiscible water-gas flow in porous media. The relation between saturation and relative permeability becomes more important when the capillary force can be disregarded and viscous friction force governs the flow. In this study, a 2-dimensional finite difference numerical model was developed, in which the variation of viscosity with pressure and that of relative permeability with water saturation can be treated. Seven cases of parallel plate tests were performed in order to obtain the characteristic equation of relative permeability which would be used in. the developed numerical model. It was not possible, however, to match the curves of relative permeability from the plate tests with the existing emperical models. Consequently a logistic equation was proposed as a new emperical model. As this model was composed of the parameter involving aperture size, any aperture size of fracture can be applied to the model. For the purpose of verification, the characteristic equation of relative permeability was applied to the developed numerical model and the computed results were compared with those of plate test. As a result of application of numerical model, in order to check the field applicability, to single fracture surrounding an underground storage cavern, the simultaneous flow of water and propane gas was able to be simulated properly by the model.

• Child Health Nursing Research
• /
• v.8 no.2
• /
• pp.174-182
• /
• 2002

The purpose of this study was to investigate the experiences of accident and visiting emergency center, and the experiences of education about emergency care for parents. The subjects of this study were 117 mothers whose children are attending 9 different nursery schools or kindergartens. The instrument used in this study was developed by researchers and validated by nursing professor, first aid doctor and the president of nursery school, and consisted of 'most important thing in child rearing' ,'experiences of accident and visiting emergency center', 'type of trauma' and 'need for parent education program' the result of this study were as followed ; 1.There were 70.09％ of the experience of visiting emergency center among the subjects. The cause of visiting emergency center were high fever and convulsion(42.86％), and trauma by accident(28.04％) 2. The most common type of the indoor accident were fall down and slipping(76.92％), the common type of trauma were contusion (76.92％), abrasion(47.01％), laceration(29.06％), dislocation or fracture(12.82％), burn(10.26％), piercing(8.55％). 3.47.01％ of subjects had the experience of education about emergency care for parents. They were educated by child rearing journals (32.72％), small books which were published by hospitals or community health center (25.45％), mass media(21.8％), parent seminar (12.72％), nursery school or kindergarten (5.45％). In conclusion, the need of emergency care for children was strongly found. Therefore, on the basis of above results, the parent education program which fits their cognitive level and their health care needs So, it must be directed on the further study of parents' knowledge about emergency care for children. To enhance the effectiveness of program and accomplish the children's health promotion, advanced instructional media and demonstration must be included.

• The Journal of Engineering Geology
• /
• v.13 no.1
• /
• pp.129-137
• /
• 2003

We interpreted the seismic signal characteristics from crosswell seismic tomography in the underground cavity like abandoned mines. The first arrival time delay and amplitude attenuation showed clearly at the low velocity zone of cavity and fracture. Also ray density decreased by detour of raypath. As a result of the amplitude spectrum analysis of fresh rock and low velocity zone, there were no noticeable differences of the amplitude up to about 1000Hz frequency, but indicated that the one passed around cavity decreased about 7dB at 2000Hz, and 20dB at 3000Hz. It was possible to compare the signal characteristics between two media by extracting the signal data from the fresh rock zone and the underground cavity through the seismic crosswell tomography.

• Journal of Korean Neurosurgical Society
• /
• v.29 no.8
• /
• pp.1050-1054
• /
• 2000

Objective : The incidence of head injury has been increasing in the rural area. The author investigated the clinical features and difficulties in care of the acute head-injured patients in this area. Method and Material : The authors performed a retrospective review of radiological data and clinical records in patients with mild to moderate head injury. Cause, type of craniocerebral injury, delayed intracranial lesions, complications, its relation to alcohol abuse, and outcome were analyzed. Results : In total of 68 cases, 20(29.4%) victims were associated with acute alcohol intoxication. Motor vehicle accident was the leading cause of head injury and the most common craniocerebral lesion was basilar skull fracture. Eight(11.8%) patients showed delayed radiological and clinical deterioration and 40(58.8%) were followed-up regularly after discharge. The subdural hygroma was commonly noted in the elderly and alcoholics. Causes of thirty events that resulted in an atypical and difficult neurosurgical practice were as follows : delayed admission, premature discharge against doctor's request, refusal of radiological studies and admission, misunderstanding of disease entity, and unreasonable desire of transfer to tertiary hospitals. Inaccurate initial diagnoses were made by emergency doctors in twenty patients. During the course of treatment, there were a few complications such as alcohol withdrawal, acute otitis media, cerebrospinal fistula, facial weakness, and posttraumatic seizure. Outcome was good in 60(88.2%) patients. Conclusion : Most of minor head trauma patients in this series have shown good results, but we have to consider some possible complications and delayed intracranial lesions in these patients that should be managed with special cautions with various kinds of treatment difficulties.

• Geomechanics and Engineering
• /
• v.9 no.6
• /
• pp.793-813
• /
• 2015

Characterization of discontinuous media is an endeavor that poses great challenge to engineers in practice. Since the inherent defects in cracked domains can substantially influence material resistance and govern its behavior, a lot of work is dedicated to efficiently model such effects. In order to overcome difficulties of material instability problems, one needs to comprehensively represent the geometry of cracks along with their impact on the mechanical properties of the intact material. In the present study, stress-strain results from laboratory experiments on Inada granite was used to derive crack tensor as a tool for the evaluation of fractured domain stability. It was found that the formulations proposed earlier could satisfactorily be employed to attain crack tensor via the invariants of which judgment on cracks population and induced anisotropy is possible. The earlier criteria based on crack tensor analyses were reviewed and compared to the results of the current study. It is concluded that the geometrical parameters calculated using mechanical properties could confidently be used to judge the anisotropy as well as strength of the cracked domain.

• Nuclear Engineering and Technology
• /
• v.25 no.4
• /
• pp.539-547
• /
• 1993

A stochastic approach using continuous time Markov process is presented to model the one-dimensional nuclide transport in fractured rock media as a further extension for previous works［1-3］. Nuclide transport of decay chain of arbitrary length in the single planar fractured rock media in the vicinity of the radioactive waste repository is modeled using a continuous time Markov process. While most of analytical solutions for nuclide transport of decay chain deal with the limited length of decay chain, do not consider the case of having rock matrix diffusion, and have very complicated solution form, the present model offers rather a simplified solution in the form of expectance and its variance resulted from a stochastic modeling. As another deterministic way, even numerical models of decay chain transport, in most cases, show very complicated procedure to get the solution and large discrepancy for the exact solution as opposed to the stochastic model developed in this study. To demonstrate the use of the present model and to verify the model by comparing with the deterministic model, a specific illustration was made for the transport of a chain of three member in single fractured rock medium with constant groundwater flow rate in the fracture, which ignores the rock matrix diffusion and shows good capability to model the fractured media around the repository.

• Economic and Environmental Geology
• /
• v.55 no.1
• /
• pp.111-125
• /
• 2022

Since landslide can cause huge damages to many facilities, close characterization of slopes is needed for appropriate reinforcements for the unstable ones in order to prevent the damages. Geophysical surveys, which can characterize a large area at a relatively low cost without disturbing slopes, have been widely employed for the assessment of slope stability in other countries. However, only conventional direct investigation methods are mainly used in Korea. In this paper, we analyzed various cases, which evaluated slope stabilities by characterizing slopes using geophysical exploration. First, we introduced changes in geophysical properties due to unstable media of slope like fracture location, fracture connectivity and distribution of groundwater level, and subsequently discussed the applicability of geophysical methods to the detection of the changes; the methods include electrical resistivity survey, seismic survey, self-potential survey, induced polarization survey and ground penetrating radar. Based on this description, we analyzed how geophysical surveys were performed on various slopes.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.4
• /
• pp.393-403
• /
• 2011

The purpose of this study was to analyze and compare survival rates of resorbable blast media(RBM) surface and acid-etched surface implants being usually used in clinics. RBM surface implants (USII, Osstem, Busan, Korea) or acid-etched surface implants ($Osseotite^{(R)}$, Biomet $3i^{[TM]}$, FL, USA) were placed in edentulous area of 140 patients between January of 2005 and March of 2007. The number of implants was 304, and 152 out of them were RBM surface implants while another 152 were acid-etched surface implants. According to the evaluation items, the survey was performed before and after the implants installations. The 3-year survival rates of both kind of implants were calculated. 1. Total of 152 RBM surface implants were placed. Among them, one implant was failed, which was implanted in the posterior mandible with D2 bone quality. The failure was resulted from fracture of the fixture. Others showed good results and survival rate of RBM surface implant was 99.34%. 2. Total of 152 acid-etched surface implants were placed. Seven implants of them were failed, thus, survival rate was 95.39%. The causes of the failures were considered as infection, overheat and the lack of initial stability. In this research, both implants showed good 3-year survival rate, although RMB surface implant represented a better result.

• Nuclear Engineering and Technology
• /
• v.25 no.4
• /
• pp.529-538
• /
• 1993

A stochastic way using continuous time Markov process is presented to model the one-dimensional nuclide transport in fractured rock matrix as an extended study for previous work ［1］. A nuclide migration model by the continuous time Markov process for single planar fractured rock matrix, which is considered as a transient system where a process by which the nuclide is diffused into the rock matrix from the fracture may be no more time homogeneous, is compared with a conventional deterministic analytical solution. The primary desired quantities from a stochastic model are the expected values and variance of the state variables as a function of time. The time-dependent probability distributions of nuclides are presented for each discretized compartment of the medium given intensities of transition. Since this model is discrete in medium space, parameters which affect nuclide transport could be easily incorporated for such heterogeneous media as the fractured rock matrix and the layered porous media. Even though the model developed in this study was shown to be sensitive to the number of discretized compartment showing numerical dispersion as the number of compartments are decreased, with small compensating of dispersion coefficient, the model agrees well to analytical solution.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.2
• /
• pp.183-192
• /
• 2008

Modern dental reconstructions do not only aim at restoring the patient's mastication, but rather at improving general well-being and quality of life, especially in terms of esthetics. The media, the internet, advertising, and many other facts of society contribute to an increased cosmetic awareness. A 35-year-old male patient presented with as follows: 1) the porcelain fracture of ceramo-metal restoration on #11 and #23, 2) the inclination of incisal plane to horizontal reference plane, 3) the dental midline deviation to facial midline, and 4) the lack of symmetry on upper anterior dentition. The patient requested an aesthetic improvement using fixed prosthodontics including implant-supported restorations. In the upper anterior region, one of the goals of the conventional as well as implant prosthesis is to achieve restorations with the dental attractiveness and beauty in the respect of dental, dentofacial, and facial compositions. This case report presents geometrically improvement of dental esthetics using conventional and implant prosthesis with soft and hard tissue augmentation.