• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.285-290
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• 2000

This paper was undertaken to do morphological analysis of wear debris for slipper-pad of hydrauric rotary acuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials. varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used showed that the four shape parameters of wear debris depend on a kind of the lubricating condition. It was capable of presuming wear volume for slipper-pad of hydrauric rotary acuator on driving time.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.186-193
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• 2001

In the high pressure state, the leakage flow rate of hydraulics is one of serious problems and the great reason to decrease the volume efficiency. In this paper, I tried to clarify tribology characteristics for the slipper hydrostatic bearing in swash plate type axial piston pumps and motors by means of experiment . I measured the leakage flow rate between swash plate and piston shoe with change the supply pressure and oil temperature at a swash plate angle of 0。 . And I also investigated the slipper pocket pressure and calculated oil film thickness for theoretical method. So. 1 have analyzed the tribology characteristics of hydrostatic bearing for leakage flow rate and oil film thickness with oil temperature and supply pressure.

• Journal of Ocean Engineering and Technology
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• v.23 no.5
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• pp.39-44
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• 2009

The hydrostatic slipper bearing is generally used in high pressure axial piston pumps to support the load generated from two surfaces which are sliding relatively at low speed. The object of the bearing is to remove the possibility of direct contact by maintenance of an adequate oil film thickness between two metal surfaces. Because the bearing performance is influenced by the bearing deformation, it is highly dependent on the injection pressure, the bearing surface profile and so on. In this study, the deformation characteristics of a hydrostatic slipper bearing is investigated according to the injection pressure by the finite element analysis. In the analysis, the special boundary condition to take the fluid-structure interaction (FSI) into account is used on the interactive surface. The results, such as bearing deformation, stress and lifting force, obtained from the fully coupled analysis are compared with those from the single step sequential method.

• Journal of Drive and Control
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• v.18 no.4
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• pp.84-90
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• 2021

Viscosity of hydraulic oils decreases due to loss reduction and efficiency increase of fluid power systems. However, low viscosity is not always appropriate due to the induction of large leakage and small lubricity. Therefore, a detailed study on the optimum viscosity of hydraulic oils is necessary. In this study, based on the thermohydrodynamic lubrication theory, numerical simulation was conducted using the slipper model of swashplate-type axial piston pumps and motors. The viscosity grades' (VG) effects of oils on power losses are mainly discussed numerically in fluid film lubrication, including changes in temperature and viscosity. The simulation results reveal that the flow rate increases and the friction torque decreases as VG decreases. The film temperature and power loss were minimised for a specific oil with a VG. The minimum conditions regarding the temperature and loss were different and closed. Under various operating conditions, the film temperature and power loss were minimised, suggesting that an optimum hydraulic oil with a specific VG could be selected for given operating conditions of pressure and speed. Otherwise, a preferable operating condition must be established to determine a specific VG oil.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.53-53
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• 2019

Cypripediums, popularly called lady's slippers or moccasin flowers, are the showiest and most sought after hardy terrestrial orchids, collected and grown by orchid and alpine plant enthusiasts alike. In Korea, 4 species of cypripedium are reported as Cypripedium japonicum, C. macranthos, C. guttatum, and C. calceolus. We had already reported the feasibilities of C. macranthos and C. guttatum with in vitro germination methods from immature seeds. The seeds of white lady's slipper orchid (Cypripedium macranthos Sw. alba) were collected 65 days after pollination in 2018. The green pods were sterilized with flame and sowed immediately on the POM(Phytomax orchid maintenance media(R), Sigma) supplemented with BAP 0, 0.5, 1.0 mg/L and NAA 0, 1, 2mg/L. The germination of seed was observed 90 days after sowing, and the plantlets were subcultured to the same media according to the size of the protocorm with 1~2, 2~3, 3~4, 5~6, 7~8mm. The time of the subculture to the new media seems to be critical factors of forming rhizoids which is the hairy root of the cypripediums. As a results, the protorms of the white lady's slipper orchid was successfully germinated in the POM media supplemented BAP 0.5 and NAA 1.0 mg/L. The roots and rhizoids were formed in 5~6mm protocorms subculture over 95% survival ratio. We also tried to subculture to liquid medium without activated charcoal, however the browning or malformation of the roots was observed in the root. The formation of shoots from the protocorm was effectively enhanced in the POM media with non-additives of plant growth regulators. These results indicate the possibility of high and stable production and practical industrialization of endangered white lady's slipper orchids.

• Journal of Drive and Control
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• v.9 no.4
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• pp.71-78
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• 2012

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.37-37
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• 2018

We use two different methods for laboratory propagation from seed of lady's slipper orchid(Cypripedium macranthos Sw.); immature seed which also called green capsule or fully mature seed about 120~130 days from pollination. In green capsule culture, the seed pods should be collected within precisely right time. The right time of seed collection could be diverse under the wether conditions or nutritional factors of the plants. In fully matured seed culture, the more complicated procedures are needed to break the dormancy of the seed; thermal or chemical treatment. The seedlings in this study were easily germinated from immature seeds in Harvais medium; 53 days after pollination(DAP) in Cypripedium pubescens, DAP 65 in C. parviflorum and C. macranthos. The germinated seedlings were transplanted to hormone free media immediately to avoid abnormal growth of seedlings. When the seedlings have roots with a minimum length of around 2-3cm and have visible dormant buds, the seedlings were removed from the flask and stored in refrigerator for vernalization. To examine the correlation of seedlings and maternal plants, the 125 seedlings of C. macranthos were transplanted in the soil bed at a distance of 20-100 cm from mother plants on April 20. The survival rate of seedlings were 92% in 20 cm distance from the ripe plants, and 56 % in 100 cm distance. The seedlings which were transplanted near mother plants showed vigorous growth in plant height, leaf width, and especially dormant buds. Considering the existence of mycorrhiza which is a symbiotic association between a fungus and the roots of a orchid vascular, the various fungus from mother plants could affect the growth of the seedlings. These results indicate the possibility of high and stable production and practical industrialization of endangered lady's slipper orchids.

• Journal of Environmental Health Sciences
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• v.13 no.1
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• pp.17-33
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• 1987

As a result of technical advances and industrialization, the characteristics of domestic and industrial wastes are becoming more complex. Accordingly, improved treatment and disposal systems are being continuously sought to take account of complex characteristics and to comply with economic restrictions. In this study, an application of pyrolysis to the treatment of industrial wastes, including waste scrap rubber, waste raw material used in making the slipper bottom and waste PVC pipe, and the effectiveness of pyrolysis in resource recovery from these wastes were investigated. Batches of wastes were pyrolysed by external heating to a temperature of 400-800$\circ$C in a 32 mm diameter x 0.9 m long silica tube to produce combustible gases, oils and chars. Before the start of pyrolysis runs, the entire system was purged with nitrogen gas to exclude the air. The temperature inside the retort was controlled by the thermocouple in the gas stream, and referred to as the pyrolysis temperature. Under these conditions three products were separately collected and further analyzed. The results were summarized as follows. 1. More gases and less chars were produced with higher pyrolyzing temperature and with higher rates of heating, but the yields of oils tended downwards at temperatures above 700$\circ$C. Accordingly, operating conditions of pyrolysis should be varied with desired material. 2. Calorific values and sulfur contents of produced oils were sufficient and suitable for fuel use. Chars from waste rubber had high heating values with low sulfur contents, but calorific values of chars from waste PVC and waste slipper were as low as 3, 065-4, 273 kcal/kg and 942-2, 545 kcal/kg, respectively. Therefore, char from these wastes are inappropriate for fuel. 3. Soluble contents of Pb, Cd, Cu and Zn in chars from waste rubber and waste slipper were below the Specific Hazardous Waste Treatment Standards. However soluble contents of Pb and Cd in chars from waste PVC were one or two times and five or seven times exceedingly the Specific Hazardous Waste Treatment Standards, respectively. 4. Post high heating is desirable for treatment method of waste PVC which generates toxic hydrogen chloride. 5. The proportions of hydrogen, methane and ethane in produced gases were in the range of 3.99-35.61% V/V, 18.22-32.50% V/V and 5.17-5.87% V/V, respectively. 6. Pyrolysis is a useful disposal method in case of waste slipper, which was hardly combustible, and thus investigations of this kind of materials are required for effective management of industrial waste. 7. Based upon the possible market development for products, overall pyroly economics to take account of treatment values of noncombustible or hazardous materials should be evaluated.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.45-45
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• 2018

We had already reported the successful germination for green pods of purple lady's slipper orchid (Cypripedium macranthos Sw.). The green pod methods is to take immature seeds in green capsules, sterilize the capsule, and take out the sterile seeds. This method, however, needs very critical time of harvest. The critical time of seed harvest changes depending upon the species, condition of the specimen, and climatic influence, and the right time lies between 5 and 12 weeks after fertilization. In this study, the mature seeds were collected after 120-130 days with hand-polination of lady's slipper orchids. Mature seeds are usually dormant and it has to be overcome, either with hormone or storing the seeds near freezing for two or three months to break dormancy. The seeds were first surface sterilized with 70% ethanol and then transferred 1% NaOCl for 10-15 minutes, followed by rinses 3 times with sterilized distilled water. The cypripedium seeds consists of an embryo within a seed coat known as a testa. The testa is water repellent and the seed has a large air space between the embryo and testa so the seed tends to float on water. We had resolved the problems with vacuum pump to soak water into the testa before sterilization. The seeds were placed on liquid or agar solidified germination media. Cultures were incubated at $24{\pm}1^{\circ}C$ in dark. The seeds were germinated in 6-8 weeks in liquid suspension culture (germination percentage over 18%); however, the seeds on agar solidified media took more than 5 months to germinate and the germination percentage less than 5%. The most effective media for liquid culture was 1/4 strength Murashige and Skoog (MS) medium with 50 ml/l coconut water ($4brix^{\circ}$) at pH 5.8.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.23-23
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• 2019

Cypripedium is an orchid genus of over 50 species widely distributed in the northern temperate zone, with a few taxa extending central America and the Himalayas and the southwesternmost tip of China in Asia. Of the known species approximately two thirds are found in China. In Korea, 4 species were reported to find with rare popularity ; C. macranthos, C. guttatum, C. japonicum, and C. calceolus. The seed has a firm brown fusiform testa with an opening at one end where the micropyle of the ovule was situated. Cypripedium has small, fusiform, wind-dispersed seeds that weigh about $1{\sim}2{\mu}g$ and range from 0.1 to 2 mm long and 0.07 to 0.4 mm across. The germination of Cypripedium was previously thought to be hard to cultivate in one's garden and impossible to propagate artificially, nowadays lab-propagated seedlings are readily available in EU or United States. We had already reported the successful micropropagation of lady's slipper orchids with green pod sowing methods. The collected Cypripedium species and hybrids were planted in Korea National Arboretum (KNA) on Oct. 2018. The 11 species including C. candidum and the 31 hybrids such as C. Ingrid were introduced from Germany with CITES certification. The lady's slipper orchids bloomed on May to June, and the flowers were pollinated in the same species or hybrids to get seeds for in vitro germination on 2~3 days after fully flowering. The green pods were collected after 49~70 days after pollination. The 6 species of Cypripedium seeds were easily germinated on the POM within 70 days after sowing, and the 12 hybrids PLBs were observed with small roots. We had established the scheme of lady's slipper orchids germination in 3 months with green pods, and get the possibility of seedling in 10 months of sowing in vitro.