• Tuberculosis and Respiratory Diseases
• /
• v.70 no.4
• /
• pp.323-329
• /
• 2011

Background: Although patients with tuberculous-destroyed lung (TDL) account for a significant proportion of those with chronic airflow obstruction, it is difficult to distinguish patients with airway obstruction due to TDL from patients with pure chronic obstructive pulmonary disease (COPD) on initial presentation with dyspnea. We investigated clinical features differing between (i) patients with TDL and airway obstruction and (ii) those with COPD admitted to the intensive care unit (ICU) due to dyspnea. Methods: We reviewed the medical records of patients with TDL who had a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) of <70% on a pulmonary function test (PFT; best value closest to admission) and patients with COPD without a history of pulmonary tuberculosis (TB) who were admitted to the ICU. Ultimately, 16 patients with TDL and 16 with COPD were compared, excluding patients with co-morbidities. Results: The mean ages of the patients with TDL and COPD were 63.7 and 71.2 years, respectively. Mean FVC% (50.4% vs. 71.9%; p<0.01) and mean FEV1% (39.1% vs. 58.4%; p<0.01) were significantly lower in the TDL group than in the COPD group. More frequent consolidation with TB (68.8% vs. 31.3%; p=0.03) and more tracheostomies (50.0% vs. 0.0%; p=0.02) were observed in the TDL than in the COPD group. Conclusion: Upon ICU admission, patients with TDL had TB pneumonia more frequently, more diminished PFT results, and more tracheostomies than patients with COPD.

• The Journal of Korean Society for School & Community Health Education
• /
• v.15 no.1
• /
• pp.105-119
• /
• 2014

Objectives: This study investigates the factors influencing values on life-respect among middle school students. Methods: The participants in this study were 126 students from S middle school and Y middle school, both located in Gyeongnam province. The experimental group consisted of 40 students from S middle school, Control group-Iconsisted of 39 students from S middle school, and Control group-II consisted of 47 students from Y middle school. The experimental group was provided with 12 incidences of the life-respect education program from April 1st to June 29th. One period took 45 minutes and proceeded according to a structure of introduction, development, and consolidation. The experimental group received a life-respect education program, Control group-I received health teaching, but Control group-II didn't receive any special education except what was regularly part of their curriculum. The content of the life-respect education program included the following topics: value of life-respect, respect for human life and ethics, life-respect campaign, having a healthy mind, suicide prevention, dealing with crisis, prevention of school violence, abortion and life-respect, social weak minority consideration, death, brain death, euthanasia, life cycle and task, and forest activities. Questionnaires were administered as pre and post-tests which consisted of questions regarding death anxiety, suicide risk, and values on life-respect. The pre and post-tests were analyzed with t-tests, paired t-tests, ANOVAs, and factor analyses using SPSS 18.0. Results: 1. There was a statistically significant increase in the experimental group(p<.0001) and control group-I(p<0.05) in value and attitude about life-respect. On the other hand, it was shown that there was no difference between pre and post-test in control group-II. 2. The result of examining the differences between pre and post-tests after education on values and attitudes toward life-respect using ANCOVA showed, there was a statistically significant difference (p<0.001) among the three groups. Conclusion: the life-respect education program which was conducted over 12 meeting with middle school students had an positive effect, which can be used as basic data for fostering values on life-respect. These findings indicate that the life-respect education program this study used is effective for fostering value of life-respect and decreasing suicide risk.

• Korean Journal of Mineralogy and Petrology
• /
• v.35 no.1
• /
• pp.51-64
• /
• 2022

For effective preservation of the rocks, which bearing plant fossils at Gumkwangdong Formation, Pohang, the properties of rock and treatment of chemicals were examined in an artificial weathering test. The rocks are diatomaceous siliceous mudstone, which contain a small amount of smectite and has developed laminated layers. The rocks react with water, the d₀₀₁ spacing of smectite was increased. On the one hand, the physical properties of the rock samples, such as surface hardness, improved after the application of ethyl silicate-based stone strengthener. On the other hand, the spacing of interlayer of swelling clay minerals decreased and spacing of laminae layer increased. When the ethyl silicate-based stone strengthener was applied after pretreatment with a swelling inhibitor, interlayer and spacing of laminae changes were similar to those when only the stone strengthener was treated. The effect of the swelling inhibitor was almost negligible. When the rocks that have been conserved with chemicals react with water, spacing of laminae has widened much, whereas when the rocks was in contact with moisture only, there was little change. In addition, if it is placed in the outdoor after conservation treatment, although it occurs slightly slower than the untreated rock, the separation of the lamination layer and the pulverization of the rock occur within a very short time. Consolidation is required to improve the physical properties of fossil rock, but when exposed to rain and undergoing freeze-thaw process, the effect is lost very quickly. Therefore, regardless of the chemical treatment, it is a priority to prevent direct rainfall contact with the rock.

• Geomechanics and Engineering
• /
• v.25 no.3
• /
• pp.207-219
• /
• 2021

Several additives are used to enhance the geotechnical properties (e.g., shear wave velocity, shear modulus) of soils to provide sustainable, economical and eco-friendly solutions in geotechnical and geo-environmental engineering. In this study, piezoelectric ring actuators are used to measure the shear wave velocity of unreinforced, fiber, cemented, and fiber reinforced cemented Toyoura sand. One dimensional oedometer tests are performed on medium dense specimens of Toyoura sand-cement-fiber-silica flour mixtures with different percentages of silica flour (0-42%), fiber and cement (e.g., 0-3%) additives. The experimental results indicate that behavior of the mixtures is significantly affected by the concentration of silica flour, fiber and cement additives. Results show that with the addition of 1-3% of PVA fibers, the shear wave velocity increases by only 1-3%. However, the addition of 1-4% of cement increases the shear wave velocity by 8-35%. 10.5-21% increase of silica flour reduces the shear wave velocity by 2-5% but adding 28-42% silica flour significantly reduces the shear wave velocity by 12-31%. In addition, the combined effect of cement and fibers was also found and with only 2% cement and 1% fiber, the shear wave velocity increase was found to be approximately 24% and with only 3% cement and 3% fibers this increased to 35%. The results from this study for the normalized shear modulus and normalized mean effective stress agree well with previous findings on pure Toyoura sand, Toyoura silty sand, fiber reinforced, fiber reinforced cemented Toyoura sand. Any variations are likely due to the difference in stress history (i.e., isotropic versus anisotropic consolidation) and the measurement method. In addition, these small discrepancies could be attributed to several other factors. The potential factors include the difference in specimen sizes, test devices, methods of analysis for the measurement of arrival time, the use of an appropriate Ko to convert the vertical stresses into mean effective stress, and sample preparation techniques. Lastly, it was investigated that there is a robust inverse relationship between α factor and 𝞫₀ exponent. It was found that less compressible soils exhibit higher 𝜶 factors and lower 𝞫₀ exponents.

• Journal of the Korean Geotechnical Society
• /
• v.26 no.6
• /
• pp.5-19
• /
• 2010

The purpose of this study is to figure out the effect of pressurized grouting on the pullout resistance and the group effect of the compression ground anchor by performing pilot-scale chamber tests and field tests. The laboratory tests are carried out for 3-types of soils which are abundant in the Korean peninsular. Experimental results showed that the enlargement of anchor diameters estimated from the cavity expansion theory matches reasonable well with that obtained from experiments. Moreover, the required injection time as a function of the coefficient of permeability of each soil type was proposed. A series of in-situ anchor pullout tests were also performed to experimentally figure out the effect of pressurized grouting on the pullout resistance. Experimental results also showed that the effect of the pressurized grouting is more prominent in a softer ground with smaller SPT-N value in all of the following three aspects: increase in anchor diameter; pullout resistance; and surface roughness. The pressurized grouting effect in comparison with gravitational grouting was found to be almost nil if the SPT-N value is more than 50. Based on experimental results, a new equation to estimate the pullout resistance as a function of the SPT-N value was proposed. And based on in-situ group anchor pullout tests results, a new group effect equation was proposed which might be applicable to decomposed residual soils which are abundant in the Korean peninsular.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.3
• /
• pp.25-40
• /
• 2007

Excessive earth pressure is one of the major mechanical factors in the deformation and damage of Cut-and-Cover Tunnel lining in shallow tunnels and portals of mountain tunnels (Kim, 2000). Excessive earth pressure may be attributed to insufficient compaction and consolidation of backfill material due to self-weight, precipitation and vibration caused by traffic (Komiya et al., 2000; Taylor et al., 1984; Yoo, 1997). Even though there were a lot of tests performed to determine the earth pressure acting on the tunnel lining, unfortunately there were almost no case histories of studies performed to determine remedial measures that reduce differential settlement and excessive earth pressure. In this study the installation of geotextile mat was selected to reduce the differential settlement and excessive earth pressure acting on the cut-and-cover tunnel lining. In order to determine settlement and earth pressure reduction effect (reinforcement effect) of geotextile mat reinforcement, laboratory tunnel model tests were performed. This study was limited to the modeling of rigid circular cut-and-cover tunnel constructed at a depth of $1.0D\sim1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. Model tests with varying soil cover, mat reinforcement scheme and slope roughness were performed to determine the most effective mat reinforcement scheme. Slope roughness was adjusted by attaching sandpaper #100, #400 and acetate on the cut slope surface. Mat reinforcement effect of each mat reinforcement scheme were presented by the comparison of earth pressure obtained from the unreinforced and mat reinforced model tests. Soil settlement reduction was analyzed and presented using the Picture Analysis Method (Park, 2003).

• Journal of the Korean Geotechnical Society
• /
• v.23 no.7
• /
• pp.17-25
• /
• 2007

Various geotechnical problems due to insufficient bearing capacity or excessive settlement are likely to occur when constructing roads or large complexes on soft ground. Accurate predictions of the magnitude of settlement and the consolidation time provide numerous options of ground improvement methods and, thus, enable to save time and expense of the whole project. Asaoka's method is probably the most frequently used one for settlement prediction and the empirical formulae such as Hyperbolic method and Hoshino's method are also often used. To find an elaborate method of predicting the embankment settlement, two recurrent type neural network models, such as Jordan model and Elman-Jordan model, are adopted. The data sets of settlement measured at several domestic sites are analyzed to obtain the most suitable model structures. It was shown from the comparison between predicted and measured settlements that Jordan model provides better predictions than Elman-Jordan model does and that the predictions using CPT results are more accurate than those using SPT results. It is believed that RNN using cone penetration test results can be a highly efficient tool in predicting settlements if enough field data can be obtained.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.6
• /
• pp.27-40
• /
• 2006

Damage of cut-and-cover tunnel lining can be attributed to physical and mechanical factors. Physical factors include material property, reinforcement corrosion, etc. while mechanical factors include underground water pressure, vehicle loads, etc. This study is limited to the modeling of rigid circular cut and cover tunnel constructed at a depth of $1.0{\sim}1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. In this study, only damages due to mechanical factors in the form of additional loads were considered. Among the different types of additional, excessive earth pressure acting on the cut-and-cover tunnel lining is considered as one of the major factors that induce deformation and damage of tunnels after the construction is completed. Excessive earth pressure may be attributed to insufficient compaction, consolidation due to self-weight of backfill soil, precipitation and vibration caused by traffic. Laboratory tunnel model tests were performed in order to determine the earth pressure acting on the tunnel lining and to investigate the applicability of existing earth pressure formulas. Based on the difference in the monitored and computed earth pressure, a factor of safety was recommended. Soil deformation mechanism around the tunnel was also presented using the picture analysis method.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.6
• /
• pp.541-554
• /
• 2023

The utilization of underground spaces in relation to tunnels and energy/waste storage is on the rise. To ensure the stability of underground spaces, it is crucial to reinforce rock fractures and discontinuities. Discontinuities, such as joints, can weaken the strength of the rock and lead to groundwater inflow into underground spaces. In order to enhance the strength and stability of the area around these discontinuities, rock grouting techniques are employed. However, during rock grouting, it is impossible to visually confirm whether the grouting material is being smoothly injected as intended. Without proper injection, the expected increases in strength, durability, and degree of consolidation may not be achieved. Therefore, it is necessary to predict in advance whether the grouting material is being injected as designed. In this study, we aimed to assess the injection performance based on injection variables such as the water/cement mixture ratio, injection pressure, and injection flow using UDEC (Universal Distinct Element Code) numerical program. Additionally, numerical results were validated by the lab experiment. The results of this study are expected to help optimize variables such as injection material properties, injection time, and pump pressure in the grouting design in the field.

• Tuberculosis and Respiratory Diseases
• /
• v.51 no.4
• /
• pp.354-363
• /
• 2001

Background : Although lung involvement has been reported in 5 to 46% of dermatomyositis/polymyositis(DM/PM) patients, reports of the condition in Korea are rare. This study evaluated the clinical features of lung involvement in DM/PM patients. Methods : The medical records, laboratory results and radiologic findings of 79 DM/pM patients, who attended the Seoul National University Hospital (SNUH) between 1989 and 1999, were reviewed retrospectively. Results : A total 79 patients of whom 24 patients(33%) showed lung involvement, were enrolled in this study. More patients with lung involvement were female(F:M=11:1), and older compared with those without lung involvement. Patients with lung involvement presented with dyspnea(79%), coughing(67%), an elevated ESR, and CK/LD. Anti-Jo 1 antibody test was positive in 30%, which is significantly higher in patients with lung involvement. A simple chest X-ray of the patients with lung involvement exhibited reticular opacity(50%), reticulonodular opacity(30%), patchy opacity(29%), nodular opacity(13%) and linear opacity(4%). HRCT(n=24) showed ground glass opacity(75%), linear or septal thickening(50%), patchy consolidation(42%), honey-combing(33%) and nodular opacity(17%). The pulmonary function test showed a restrictive ventilatory pattern(77%) and a lower diffusing capacity(62%). The patients were followed up during a mean duration of $30{\pm}28$ months. They were treated with steroid only(50%) or a combination of steroids and cytotoxic agents(46%). Muscle symptoms were improved in 89% with treatment, but an improvement in the respiratory symptoms or in the pulmonary function test was rare. Patients with lung involvement had a higher mortality rate(21%) than those without lung involvement(10%) during the follow-up periods. Conclusion : DM/PM patients with lung involvement were mostly female, older and had a higher positive rate Anti-Jo 1 antibodies, but there was no significant difference in prognosis.