• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.3
• /
• pp.300-310
• /
• 1999

A constant-volume combustion chamber is developed to measure the burnt gas temperature over the wide ranges of equivalence ratio from 1.5 to 2.7 and pressure from 0.1 to 2.7 and pressure from 0.1 to 6 MPa by two-color method. The combustion temperature is also calculated by the conventional two-region model. The premixed fuel rich propane-oxygen-inert gas mixtures under high pressures are simultaneously ignited by eight spark plugs located on the circumference of combustion chamber with 45 degree intervals. The eight converging flames compress the end gases to high pressures. The transmissiv-ity in the chamber center during the final stage of combustion at the highest pressure is measured by in situ laser extinction method. Comparisons are made with the combustion temperatures between two-color method and two-region model. It is found that the burnt gas temperature mea-sured by two-color method is higher than that calculated by two-region model because of being the negative temperature gradient on the calculation and the temperature distribution of light path-length on the measurement and the burnt gas temperature for the turbulent combustion is higher than that of the laminar combustion under the same conditions because the heat loss for turbulent combustion is lower due to the shorter combustion period.

• Clinical and Experimental Pediatrics
• /
• v.50 no.6
• /
• pp.588-591
• /
• 2007

Left ventricular thrombus is mainly caused by anterior myocardial infarction or severe cardiac wall dysfunction of the apex, and is rarely caused by a complication of acute myocarditis. A 12-year-old female who developed symptoms of motor dysphasia and incomplete hemiparesis of the right side was admitted to the hospital. The brain MRI taken on the day of her admission showed acute cerebral infarction in the left basal ganglia and the frontoparietal lobe. The echocardiogram showed a movable thrombus, which was $19{\times}28mm$ sized and located in the apex of the left ventricle. So in order to prevent further thromboembolic event we performed open cardiac surgery via the atrium and removed the thrombus of the left ventricle. After the removal of the thrombus her symptoms improved and she was discharged from the hospital. Thrombus formation in acute viral myocarditis are considered to be related with endocardial injury and blood flow stasis. Treatment with anticoagulants in left ventricular thrombosis may not be effective and may even cause a major thromboembolism. When the thrombus is laminar and fixed, one should consider anticoagulant therapy. But if the thrombus is pedunculated and movable, which means that there are higher possibilities of major embolism or there may be already one, one should consider surgical removal. We report a 12-year-old girl who required surgical removal of a left ventricular thrombus caused by acute viral myocarditis.

• Journal of Korea Water Resources Association
• /
• v.44 no.10
• /
• pp.797-807
• /
• 2011

Phenomenon of vegetation recruitment on the sand bar is drastically rising in the streams and rivers in Korea. In the 1960s prior to industrialization and urbanization, most of the streams were consisted of sands and gravels, what we call, 'White River'. Owing to dam construction, stream maintenance, etc. carried out since the '70s, the characteristic of flow duration and sediment transport have been disturbed resulting in the abundance of vegetation in the waterfront, that is, 'Green River' is under progress. This study purposed to identify the correlation among water level, water temperature, rainfall, soil moisture and soil texture out of the factors which give an effect on the vegetation recruitment on the sand bar of unregulated stream. To this purpose, this study selected the downstream of Naeseong Stream, one of sand rivers in Korea, as the river section for test and conducted the monitoring and analysis for 289 days. In addition, this study analyzed the aerial photos taken from 1970 to 2009 in order to identify the aged change in vegetation from the past to the present. The range of the tested river section was 361 m in transverse length and about 2 km in longitudinal length. According to the survey analysis, the tested river section in Naeseong Stream was a gaining river showing the higher underground-water level by 20~30 m compared to Stream water level. The difference in the underground water temperature was less than $5^{\circ}C$ by day and season and the Stream temperature did not fall to $10^{\circ}C$ and less from May when the vegetation germination begins in earnest. The impact factor on soil moisture was the underground water level in the lower layer and the rainfall in the upper layer and it was found that all the upper and lower layer were influenced by soil particle size. The soil from surface to 1 m-underground out of 6 soil moisture-measured points was sand with the $D_{50}$ size of 0.07~1.37 mm and it's assumed that the capillary height possible in the particle size would reach around 14~43 cm. On the other hand, according to the result of space analysis on the tested river section of unregulated stream for 40 years, it was found that the artificial disturbance and drought promoted the vegetation recruitment and the flooding resulted in the frequency extinction of vegetation communities. Even though the small and large scales of recruitment and extinction in vegetation have been repeated since 1970, the present vegetation area increased clearly compared to the past. It's found that the vegetation area is gradually increasing over time.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.4
• /
• pp.1312-1326
• /
• 2019

The purpose of this study is to examine whether the 12-week Nordic walking can improve the physical function and arthritis pain of elderly women with osteoarthritis This study were divided into randomly assigned Nordic Walking Exercise Group (n=9) and Control Group (n=7) for 16 Elderly women diagnosed with Osteoarthritis (age: 73±3.79 year, height: 154.3±4.09 cm). The exercise group used Nordic sticks to carry out 30 minutes of Nordic walking exercise three times a week for 12 weeks, and the kinetic intensity was set at 40-60% of HRR. The control group maintained daily life for the same period. Body composition (weight, percentage body fat, skeletal muscle mass), muscular strength, Flexibility (muscular strength of upper and lower limbs, flexibility of upper and lower limbs), balance ability (static balance, dynamic balance) and pain level were measured as subordinate variables. These indicators were measured twice before and after the exercise program. The study shows that percentage body fat and skeletal muscle mass in the body composition function over 12 weeks of Nordic walking exercise have significant effects after the exercise than before (p=004)(p=.003), and it also shows significant interaction effects between the groups and timings(p=.018)(p=.005). In muscular strength, Flexibility factors, there were significant effects between the groups and timings in the upper limb muscular strength and the lower limb flexibility (p=.009)(p=.036), and a significant difference between the exercise group and the control group(p=.006) in the lower limb muscular strength. In addition, in the upper limb flexibility, there was a more significant difference after the exercise than before(p=.020). There were improvement effects after the exercise than before in the balance ability and the static balance(p=.016), but no difference in the dynamic balance(p>.05). In pain, there was a significant improvement after the exercise than before(p=.022), and a significant difference between the exercise group and the control group(p=.013). In conclusion, the 12-week Nordic walking exercise has positive effects on the body composition functions of the elderly women with Osteoarthritis, and has a positive effect on the improvement of upper limb muscular strength and lower limb flexibility in the health fitness factors. These effects are believed to have contributed effectively to the improvement of the level of pain by contributing to the improvement of physical and motor functions of the elderly women with Osteoarthritis. Therefore, it is considered that Nordic walking exercise, which enhances stability and balance of the patients with Osteoarthritis by using poles, is an effective exercise method for the improvement of the body and motor functions by lowering the pain of the joints and reducing the muscular strength and percentage body fat.

• Journal of the Korean Arthroscopy Society
• /
• v.15 no.1
• /
• pp.7-12
• /
• 2011

Purpose: We purposed to evaluate clinical results after undergoing arthrocopic surgery of lateral discoid meniscus in children. Materials and Methods: Retrospective evaluation was executed for the 21 cases which showed abnormal findings of knee joint due to lateral discoid meniscus, from Janunary 1 1999 to December 30 2007. Average observation period was 38.4 months (14months~60 months), and average age was 9.5 years old (7~12 years old). The major clinical findings for knee joint extension limitations were the most common with 11 cases, and there were 8 cases of knee joint pain, 6 cases of snapping, and 10 cases of gait abnormality. The forms of lateral discoid meniscus were 14 cases of complete type, 5 cases of incomplete type, and 2 cases of Wrisberg type. All patient had arthroscopic partial menisectomy and some patient who had meniscus tear had arthroscopic meniscus repair. The clinical results were evaluated using Ikeuchi grading system, and the change of knee joint was observed through routine radiography. Results: The peripheral hypermobility of lateral disciform meniscus was observed in 7 cases. The peripheral tear was observed in 4 cases, where partial menisectomy was along with suture at the same time. The final clinical results were 5 cases of Excellent, 12 cases of Good, 4 cases of Fair. Radiologically, there were 5 cases of subchondral sclerosis and narrowness of hardness at the lateral knee joint, and osteochondritis occurred at the joint facet of external femur in 1 case. In clinical result, meanwhile, there were 20 cases of normal or almost normal and only 1 case of abnormal in IKDC score. Conclusion: Knee joint arthroscopic partial menisectomy for treatment of lateral discoid meniscus is useful, and when accompanied by peripheral disruption, suture is thought to be necessary.