• The KSFM Journal of Fluid Machinery
• /
• v.3 no.4 s.9
• /
• pp.7-14
• /
• 2000

This paper provides integrity evaluation and root cause analysis for defects observed at volute tongue, or cutwater, of the operating centrifugal pump in power plant. The cause of the cracks are analyzed and reviewed from the viewpoint of the operation and maintenance of the pumps, and the sample obtained from the cracked volute tongue of the pump are examined. At first, in-situ hardness test and microstructure examination were performed to understand the cause of cracking at volute tongue. The evaluation of structural integrity and the possibility of the crack propagation is also evaluated. Cracks were typical intergranular cracking and propagated along with prior austenite grain boundary. At easing volute tongue, the hardness was higher than ASTM requirement and a large amount of intergranular Cr carbide was precipitated. These were due to high C content in material. P content was also higher than ASTM requirement. Therefore, Cr carbide precipitation and P segregation at grain boundary, caused by higher C and P content in material, resulted in intergranular cracking of casing volute tongue. This procedure for integrity evaluation and root cause analysis is used to guide, and support the pump designer and manufacturer's material selection and process design to avoid a costly, unplanned outage of plant.

• Explosives and Blasting
• /
• v.21 no.1
• /
• pp.69-76
• /
• 2003

Test blasting has been performed with V-cut to investigate the characteristics. Blasting vibrations were measured at two directions, the proceed direction and side direction. Propagation characteristics were determined by regression analysis; square root scaled distance and cube root scaled distance with maximum charge per delay of the blast. Testing result, The cross point was 62m in the allowable vibration velocity of 3mm/sec and 46m In 5mm/sec. Also, vibration level with measuring point was highest and decayed fastest, adapting to cube root scaled distance, for the proceed direction on ground.

• Korean Journal of Medicinal Crop Science
• /
• v.19 no.1
• /
• pp.9-15
• /
• 2011

This study was conducted to establish the optimal condition for conservation of genetic resources and micropropagation of Lilium cernum. Induction of bulbet of L. cernum was highly effective (9.2 bulb/explant) on 1/2 SH (Schenk and Hildebrandt) medium supplemented with 1.0 mg/L TDZ (Thidiazuron) and 0.1 mg/L NAA (Naphthaleneacetic acid). The treatment of 0.1 mg/L NAA increased root development (6.4 root/explant) under the in vitro condition. In addition, treatments of AC (Activated Charcoal) and ventilation were enhanced to develop number of shoots and to elongate length of leaf, bulb and root. Futhermore, the process of short-term soil acclimatization was promoted to strengthen the plantlets induced under the in vitro condition.

• Korean Journal of Medicinal Crop Science
• /
• v.23 no.4
• /
• pp.271-276
• /
• 2015

This study was conducted to investigate the effect of shading degree and rooting media on the growth of Caragana sinica and Sedum middendorffianum after cutting. In C. sinica, the highest rooting rate was obtained in cuttings planted in horticultural soil (Sunshine Mix #1) and peat moss mixture (peat moss : perlite = 1 : 1, v/v) under one layer of 35% shading and in cuttings planted in kanumatsuchi soil mixture (kanumatsuchi soil : decomposition of granite = 1 : 1, v/v) under non-shading. Whereas, regardless of shading degree, most cuttings of S. middendorffianum rooted in both horticultural soil and peat moss mixture. Cuttings of C. sinica showed the highest root length, 10.4cm in kanumatsuchi soil mixture under one layer of 35% shading but the highest fresh and dry weight of roots in kanumatsuchi soil mixture under non-shading. In S. middendorffianum, the highest root length, fresh and dry weight of root were obtained in cuttings planted in horticultural soil under non-shading. With these results, we recommended that cuttings of C. sinica should be propagated in kanumatsuchi soil mixture under non-shading and cuttings of S. middendorffianum in horticultural soil under non-shading.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2006.04a
• /
• pp.502-503
• /
• 2006

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2004.10a
• /
• pp.176-176
• /
• 2004

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.171-171
• /
• 2017

Propagation by crown division in Platycodon grandiflorum is too slow for producing many plants in a short time although the plants are uniform. This study was performed to enhance the mass propagation for Platycodon grandiflorum containing yellow green petals via various medium compositions and the growth regulators. The nodes containing yellow green petals were used as materials to execute the study with a variety of MS medium concentrations. The 1/4MS medium showed the best development of adventitious root, while the 1/2MS medium exhibited the potential growth. The higher the concentration of sucrose showed the better development and growth of both shoots and adventitious roots. Many adventitious roots were developed at the controlled culture medium at pH 4.8 with a tendency of suppression with higher levels of pH. Also, the cultivated node and leaf explants with the treatments of simple and combined applications with auxin and cytokinin at the 1/4MS culture medium with adding 5% of sucrose were used to identify the influences of growth regulators. The regeneration of plantlets at the 234single application showed a good result with the addition of BA $1mg{\cdot}L^{-1}$ and the development and growth of adventitious roots appeared to be good at the addition of NAA $1mg{\cdot}L^{-1}$. For the combined applications, the regeneration of plantlets and the development of adventitious roots were prosperous at the combined applications with BA $0.1mg{\cdot}L^{-1}$ and IAA $0.5mg{\cdot}L^{-1}$. The addition of IAA for the leaf explants induced a number of plantlets that showed the potential regeneration, and the highest results was obtained from the combined applications of both BA $1mg{\cdot}L^{-1}$ and IAA $2.5mg{\cdot}L^{-1}$. In addition, the development of adventitious roots showed the satisfactory results at the combined application of both BA $1mg{\cdot}L^{-1}$ and IAA $0.5mg{\cdot}L^{-1}$.

• Plant Biotechnology Reports
• /
• v.2 no.2
• /
• pp.163-169
• /
• 2008

Roots of Ophiorrhiza prostrata D. Don serve as a rich source of camptothecin (CPT), an anticancer drug. Because of the large-scale collection of its roots, the plant has become a threatened species. The present study accomplishes the induction of adventitious roots as a means for the production of CPT as well as for the large-scale propagation of this anticancer drug plant using leaf and internode explants. The biomass yield and CPT content of adventitious roots induced from different explants were compared to roots developed on ex vitro rooted stem cuttings. Adventitious roots were produced on half-strength Murashige and Skoog (MS) medium supplemented with $10.74{\mu}M$ ${\alpha}-naphthaleneacetic$ acid and $2.32{\mu}M$ kinetin at mean fresh weights of 0.753, 0.739 and 0.748 g roots from leaf, internode and shoot, respectively. CPT yield from in vitro derived roots after 50, 80 and 120 days of incubation (0.028, 0.06 and 0.1% dry weight, respectively) was not significantly different from those harvested at the same age from ex vitro rooted (0.03, 0.06 and 0.13%, respectively) stem cuttings. CPT from subcultured roots derived from solid (0.08%) medium was lower than from suspension culture medium (0.12%). Subsequent cultures of the adventitious roots showed a stable production of CPT (0.16%). The yield of CPT from 360-day-old plant-derived roots was 0.19%. Elicitation using methyl jasmonate and acetyl salicylic acid exhibited no enhancement in CPT yield. In vitro propagation through direct shoot regeneration was achieved from the adventitious roots upon transfer to MS medium with $8.87{\mu}M$ $N^6-benzyladenine$ (BA) and $2.46{\mu}M$ indole-3-butyric acid (IBA) with a mean of 21.2 shoots per culture in 50 days. The shoots upon subculture on medium having the same level of BA and IBA underwent rapid proliferation. The shoots transferred to field conditions after in vitro rooting exhibited 95% survival. Adventitious root induction, from leaf and internode explants, enables the feasible production of CPT as well as the large-scale rapid propagation of this species which can safeguard it from extinction.

• Journal of Plant Biotechnology
• /
• v.29 no.1
• /
• pp.37-40
• /
• 2002

Sweet potato is a crop vegetatively propagated by vine cuttings, an ineffective method for maintaining pathogene-free stock plants. As an alternative method, single-node cultures of virus-free plantlets derived from apical meristem in sweet potato (cv. Yulmi) was examined. Effective pH range, sugar concentration and nodal order were investigated to establish an in vitro mass propagation system with high quality virus-free stock plantlets to farmhouse. Although the plantlets grew at wide range of pH, the most effective pH of the medium was 4.8 in single-node cultures. High sugar concentration of 60∼80 g/L resulted in increased growth response in shoot length, root length, number of node, leaf area and fresh and dry weight of shoot and root, whereas reducing sugar contents below 6% was showed reduced growth response. The first node including meristem tip was the best for the rapid growth of plantlets and the other nodes also showed a very similar growth response. Uniform plantlet can be obtained massively at the same time by culture of single node except for the first node including meristem tip. In conclusion, the most effective pH range and sugar concentration of medium for the growth of plantlets via single-node cultures was 4.8, 60∼80 g/L respectively. The first node was the best for the rapid propagation of plantlets in nodal order.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.6
• /
• pp.1031-1040
• /
• 2023

Propagation characteristics in line-of-sight(LOS) paths in 3, 6, 10, and 17 GHz frequency bands were measured and analyzed in two different indoor corridors: second floors of Buildings D2 and E2. The measurement was designed to measure when the receiving antenna moved at 0.5 m intervals from 3 m to 30 m, while the transmission antenna was fixed. The analysis of the two indoor corridors was compared by applying basic transmission loss, root mean square (RMS) delay spread, and K-factor. For basic transmission loss, the loss coefficient of the floating intercept path loss model was higher in the indoor corridor of Building E2 than in that of Building D2. Similarly, the RMS delay spread in the time domain was greater in the indoor corridor of Building E2. However, the indoor corridor of Building D2 exhibited higher K-factor in the 3, 6, and 17 GHz bands with lower wave propagation in the 10 GHz band. Despite the 2 indoor corridors being identical, the propagation characteristics varied due to different internal structures and materials. The results provide measurement data for ITU-R Recommendations regarding various indoor environments.