• Ocean Systems Engineering
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• v.5 no.2
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• pp.109-123
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• 2015

In the present study, the coupled dynamic response of a Submerged Floating Tunnel (SFT) and mooring lines under regular waves is solved by using two independent numerical simulation methods, OrcaFlex and CHARM3D, in time domain. Variations of Buoyancy to Weight Ratio (BWR), wave steepness/period, and water/submergence depth are considered as design and environmental parameters in the study. Two different mooring-line configurations, vertical and inclined, are studied to find an optimum design in terms of limiting tunnel motions and minimizing mooring-line tension. The numerical results are successfully validated by direct comparison against published experimental data. The results show that tunnel motions and tether tensions grow with wave height and period and decrease with submergence depth. The inclined mooring system is more effective in restricting tunnel motions compared to the vertical mooring system. Overall, the present study demonstrates the feasibility of this type of structure as an alternative to traditional bridges or under-seabed tunnels.

• Ocean Systems Engineering
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• v.7 no.4
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• pp.413-433
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• 2017

The dynamic and structural responses of a 1000-m long circular submerged floating tunnel (SFT) with both ends fixed under survival irregular-wave excitations are investigated. The floater-mooring nonlinear and elastic coupled dynamics are modeled by a time-domain numerical simulation program, OrcaFlex. Two configurations of mooring lines i.e., vertical mooring (VM) and inclined mooring (IM), and four different buoyancy-weight ratios (BWRs) are selected to compare their global performances. The result of modal analysis is included to investigate the role of the respective natural frequencies and elastic modes. The effects of various submergence depths are also checked. The envelopes of the maximum/minimum horizontal and vertical responses, accelerations, mooring tensions, and shear forces/bending moments of the entire SFT along the longitudinal direction are obtained. In addition, at the mid-section, the time series and the corresponding spectra of those parameters are also presented and analyzed. The pros and cons of the two mooring shapes and high or low BWR values are systematically analyzed and discussed. It is demonstrated that the time-domain numerical simulation of the real system including nonlinear hydro-elastic dynamics coupled with nonlinear mooring dynamics is a good method to determine various design parameters.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.957-961
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• 2002

The hypolipidemic effect of exe-polymer produced in submerged mycelial culture of Hericium erinaceus (HE), Auricularia auricula-judue (AA), Flammulina veluripes (FV), Phellinus pini (PP), and Grifola frondosa (GF) was investigated in dietary-induced hyperlipidemic rats. The animals were administered with exe-polymers at the level of 100 mg/kg body weight daily for four weeks. Hypolipidemic effect was achieved in all the experimental groups, however, HE exo-polymer proved to be the most potent one, which significantly reduced the plasma triglyceride ($28.9\%$), total cholesterol ($29.7\%$), low-density lipoprotein (LDL) cholesterol ($39.6\%$), phospholipid ($16.0\%$), and liver total cholesterol ($28.9\%$) level, when compared to the saline administered (control) group. The results of the present investigation strongly demonstrate the potential of HE exe-polymer in combating hyperlipidemia in the experimental animals.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.872-877
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• 2002

The hypolipidemic effect of the exe-biopolymer (EXBP) and endo-biopolymer (ENBP) produced from a submerged mycelial culture of Ganoderma lucidum was investigated in dietary-induced hyperlipidemic rats. Hypolipidemic effects were achieved in both the EXBP- and ENBP-treated groups, however, the former proved to be more potent than the latter. The administration of the EXBP (100 mg/kg body weight) substantially reduced the plasma total cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, phospholipid levels, and atherogenic index by 31.0, 39.0, 35.4, 28.1, and 53.5%, respectively, when compared to the control group. The EXBP also lowered the liver total cholesterol, triglyceride, and phospholipid levels by 22.4, 23.1, and 12.9%, respectively. Furthermore, the high-density lipoprotein (HDL) cholesterol and ratio of HDL cholesterol to total cholesterol were significantly increased by as much as 24.2% and 47.6%, respectively.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.454-455
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• 2006

This paper describes the safety assessment algorithm applied for the underground electrical utilities submerged due to flooding. In implementing the algorithm, several factors pertaining to utility safety were introduced into the process flow, and safety weight was given to each factor. It is considered that this algorithm can ensure the safety of electrical utilities installed underground when they are submerged.

• Tribology and Lubricants
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• v.39 no.4
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• pp.139-147
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• 2023

Cavitation phenomena observed during the operation of a submerged plain journal bearing (PJB) can affect bearing performance parameters such as dynamic coefficients, whirl frequency ratio, and critical mass. This study presents numerical solutions of the Reynolds equation for steadily and dynamically loaded submerged PJBs with half-Sommerfeld (HS), Reynolds, and Jakobsson-Floberg-Olsson (JFO) cavitation models when the supply pressure is larger or equal to the cavitation pressure. The loads at various eccentricity ratios are identical; however, the attitude angle is approximately 6% smaller when the eccentricity ratio is between 0.2 and 0.7 and the JFO model is used, compared to that when the Reynolds model is used. Dynamic coefficients obtained with the HS and Reynolds model show good agreement with each other, except for k_xz, which is sensitive to changes in the force normal to the rotor weight, and is attributed to the difference in the attitude angle obtained with each cavitation model. Stiffness coefficients are determined using the pressure distribution in the film, and therefore, when the JFO model is used, the direct stiffness coefficients are affected and show opposite signs for most eccentricity ratios. The mass-conservative JFO model can predict at least a 30% smaller critical mass compared to that using the HS and Reynolds models. Thus, the instability analysis results can change based on the cavitation model used in a submerged PJB. The results of this research indicate that the JFO model should be used when designing a rotor system supported by submerged PJBs.

• Journal of Mushroom
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• v.19 no.1
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• pp.1-8
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• 2021

The choice of the culture medium is an important factor for the mass production of mycelia in submerged cultures. The influence of liquid medium on the mycelial dry weight of Paecilomyces tenuipes was investigated in this study. The regression equation is expressed as Y=-1292.94187+17.78612X1+18.92425X2+2.11464X3-0.019375X1X2-0.006276X1X3+0.008177X2X3-0.070169X12-0.292175X22-0.008818X32, where Y represents the value of the mycelial dry weight (g/L), X1 is the particle size of wood sawdust in liquid medium (mesh), X2 is the concentration of the wood sawdust in liquid medium, and X3 is incubation time (h). The medium was optimized using a response surface methodology, and the optimal medium contained 30 g of wood sawdust (140 mesh), 20 g of glucose, and 10 g/L of peptone. Under these conditions, the mycelial dry weight reached 38.1 g/L (actual value). The culture medium containing wood sawdust is simple and easy to use, highly efficient, and eco-friendly, and its effectiveness in large preparations of P. tenuipes mycelia with low material costs has been demonstrated.

• Journal of Korean Society of Steel Construction
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• v.29 no.6
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• pp.401-410
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• 2017

This study deals with dynamic instability of a tendon moored submerged floating tunnel (SFT) due to tendon slack. In general, environmental loadings such as wave and current govern SFT design. Especially, the wave force, whose amplitude and direction continuously change, directly induces the dynamic behavior of the SFT. The motion of the floating tube, induced by the wave force, leads dynamic response of the attached tendons and the dynamic change of internal forces of the tendons significantly affects to the fatigue design as well as the structural strength design. When the severe motion of the SFT occurs due to significant waves, tendons might lose their tension and slack so that the floating tube can be transiently instable. In this study, the characteristics of dynamic instability of the SFT due to tendon slack are investigated performing hydrodynamic analysis. In addition, the effects of draft, buoyancy-weight ratio, and tendon inclination on tendon slack and dynamic instability behavior are analytically investigated.

• KSBB Journal
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• v.14 no.2
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• pp.167-173
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• 1999

A new synthetic medium was developed for the submerged mycelial cultures of Phellinus linteus. The medium for maximum mycelial growth of Phellinus linteus (3 days incubation, 28$^{\circ}C$, pH 5) consisted of (per 1 L): glucose, 90 g peptone, 10 g soluble starch, 10 g yeast extract, 3 g KH2PO4, 1 g MgSO4.7H2O, 1 g and CaCl2, 0.1 g. The concentrations of glucose, peptone, yeast extract, KH2PO4, MgSO4.7H2O, and CaCl2 were examined in the ranges of 10~90 g/L, 0~10 g/L, 0~15 g/L, 0~2 g/L, 0~1 g/L, and 0~0.5 g/L, respectively. The dry weight of mycelium in 3 days increased to 16.79 mg/mL using the new synthetic medium. The optimum temperature for mycelial growth of Phellinus linteus was 28$^{\circ}C$. The concentrations of KH2OP4, CaCl2, and yeast extract, which gave the maximum mycelial growth of Phellinus linteus, existed in the concentration ranges examined in this study. But, in the cases of other compositions (MgSO4.7H2O, peptone, and glucose), the mycelial growth of Phellinus linteus increased with the concentration in the ranges.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.784-788
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• 2000

Hypolipidemic effect of exo-polymers(EPs) form submerged mycelial culture of Cordyceps militaris was investigated in male Sprague-Dawley rats. For a dose-dependent study, EPs were administered at the level of 50-100 mg/kg body weight (BW) and the data was compared with the saline administered control group. A significant reduction of both the plasma total cholesterol (TC) and triglyceride (TG) was registered under the influence of EPs. It reduced the lowe density lipoprotein (LDL) cholesterol level as much as 40.5%. Levels of high density lipoprotein (HDL) choloesterol did not vary significantly within the different experimental groups, but the HDL: TC ratio showed consistently a high value with the increasing dose. The effects of cultural conditions (pH and temperature) in mycelial growth and EPs production were studied. Both the biomass and EPs were produced in a wide range of pH and temperature.