• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.3
• /
• pp.259-269
• /
• 2014

The objectives of this study to determine seasonal changes in species composition and abundance of fish and decapod assemblage, and the relationships between environmental factors and their abundance in an eelgrass bed of Jindong Bay. A total of 26 fish species and 29 decapod species were collected by a small beam trawl from an eelgrass bed in Jindong Bay in 2002. The dominant fish species were Hexagrammos otakii, Pholis neulosa and P. fangi and these accounted for 48.4 % in the total number of individuals. Dominant decapod taxa were Palaemon macrodactylus, Charybdis japonica, Pagurus minutus and C. bimaculata. These were primarily small species or early juveniles of larger species. Species composition and abundance varied greatly showing a peak in the number of individuals in April and May, and peak biomass in fish in July and decapods in August. Catch rate was low in winter months both in fish and in decapod. Seasonal changes in the abundance of fishes and decapods corresponded with eelgrass biomass and abundance of food organisms indirectly.

• Clean Technology
• /
• v.12 no.4
• /
• pp.224-231
• /
• 2006

Collection efficiencies and pressure drops for the removal of small particles from dilute liquid suspensions by granular bed filter were calculated using network model. The network model is composed of a number of nodes connected with cylindrical bond and particles are deposited on the bond surface. The collection efficiency of each cylindrical bond was predicted using unit cell model corresponding to the pore volume of cylindrical pore both at the initial and transient states. Deposited particles on the collector surface may act as additional collector and reduce the pore size of the collector. As a result, the collection efficiency was improved and pressure drop increased with deposition. Even though the stochastic nature of network requires a large number of simulation work, the model proposed in this study can be used in investigating collection efficiency and pressure drop.

• Water for future
• /
• v.28 no.4
• /
• pp.147-154
• /
• 1995

Scour characteristics of noncohesive bed materials at the downstream of free-falling jet were analyzed through hydraulic experiments. It was assumed that the downstream had no special energy dissipators. Flow characteristics of free falling jet from rectangular section were studied, and scour characteristics with and without mounds, which were generated at the downstream of the scour hole, were comparatively analyzed for various bed materials, discharges and tailwater depths. Not only the equilibrium scour depth but also the height of mound could be expressed as a function of densimetric Froude number. Densimetric Froude number had closer relationship with the equilibrium dimensionless scour depth than other dimensionless parameters. It was suggested that the mound effects should be considered at the design stage of bed protection works.

• Journal of Fisheries and Marine Sciences Education
• /
• v.18 no.3
• /
• pp.236-243
• /
• 2006

A series of surveys are performed to evaluate the abundance, composition and distribution of marine debris on the sea bed around the Busan port. In order to set up a master plan for the marine environmental pollution the relevant maritime authority must understand how many and w㏊t kinds of marine litters are distributed on the sea bed. At first we planed to survey areas divided regularly according to the coast line but there were many sea going vessels and fishing boats. So we selected and surveyed the around area where there were no sea going vessels or fishing boats.The obtained results are as follows: 1. The mean values of litters in number and weight are 5.8 pieces/㏊. and 3.5㎏/㏊. respectively. 2. The highest density in terms of number are vinyl and plastic item, and in weight are fishing gear and ship articles. 3. The nearer to the shore we surveyed the more we collected in terms of the density of marine litters in number and in weight per hectare. 4. Eel pot, oiled waste, rope, others, other pot and net of fishing gear litters in number were 59.9, 22.7, 7.9, 4.5, 3.1 and 1.9% respectively. 5. There is no relationship between the amount of fish caught and the amount of marine debris.

• 유체기계공업학회:학술대회논문집
• /
• 2005.12a
• /
• pp.244-249
• /
• 2005

Flow distribution and pressure drop analysis for an inlet plenum of a Pebble Bed Modular Reactor (PBMR) have been performed using Computational Fluid Dynamics. Three-dimensional Navier-Stokes equations have been solved in conjunction with $k-{\epsilon}$ model as a turbulence closure. Non-uniformity in flow distribution is assessed for the reference case and parametric studies have been performed for rising channels diameter, Reynolds number and angle between the inlet ports. Also, two different shapes of the inlet plenum namely, rectangular shape and oval shape, have been analysed. The relative flow mal-distribution parameter shows that the flow distribution in the rising channels for the reference case is strongly non-uniform. As the rising channels diameter decreases, the uniformity in the flow distribution as well as the pressure drop inside the inlet plenum increases. Reynolds number is found to have no effect on the flow distribution in the rising channels for both the shapes of the inlet plenum. The increase in angle between the inlet ports makes the flow distribution in the rising channels more uniform.

• Korean Journal of Hydrosciences
• /
• v.1
• /
• pp.49-60
• /
• 1990

Manning's roughness factor to flow in sand-bed channels may be divided into the grain roughness factor nd the form roughness factor. The grain roughness factor may be dedermined by using Keulegan's formula. By using available experimental data, it was found there is a unique relationship between the form roughness and the hydraulic radius to sediment particle size ratio for a given value of the Froude number. The form roughness and the bed form may be determined by using this unique relationship. The technique for engineering applications of the results appears to be quite simple.

• KSBB Journal
• /
• v.16 no.2
• /
• pp.146-152
• /
• 2001

To avoid the intrinsic problem of aggregation associated with the traditional solution-phase refolding process, we propose a solid-phase refolding method integrated with expanded bed adsorption chromatography. The model protein used was a fusion protein of recombinant human growth hormone and a glutathione S transferase fragment. It was demonstrated that the EBA-mediated refolding technique could simultaneously remove cellular debris and directly renature the fusion protein inclusion bodies in the cell homogenate with much higher yields and less agregation. To demonstrate the applicability of the method, we successfully tested the three representative types of starting materials, i. e., rhGH monomer, washed inclusion bodies, and the E. coli homogenate. This direct and simplified refolding process could also reduce the number of renaturation steps required and allow refolding at a higher concentration, at approximately 2 mg fusion protein per ml of resin. To the best of our knowledge, it is the first approach that has combined the solid-phase refolding method with expanded bed chromatography.

• Korea Journal of Hospital Management
• /
• v.11 no.3
• /
• pp.73-93
• /
• 2006

This study aims at providing necessary informations for management decision-making to the hospital manager, such as ratios of fixed and variable cost to total operating expense, and variable cost ratio to operating revenues, and determinant factors affecting cost behavior. A study model and related hypotheses were established, data were collected from 41 private university hospitals for the 6years from 1998 to 2003, and regression analyses were performed to test the hypotheses. The results of the analyses and conclusions are as follows; First, labor cost and administration cost within the same number of beds have not only fixed quality of the cost, but variable quality of that. Also, the ratio of the variable costs to operating revenue of the metropolitan was estimated 76.9% and that of other area hospitals was 80.1%. Second, the major factors affecting the increase rate of the operating expense were the increase rates of the number of inpatients, the number of employee, and the number of hospital operating bed. This result implies that maintaining a optimal hospital bed size and efficient operation of the beds are important strategic factors of hospital management.

• Journal of Biosystems Engineering
• /
• v.37 no.3
• /
• pp.155-165
• /
• 2012

This study was performed to offer the data for design of the seedling bed transfer equipment to make the automation of working process in a plant factory. The seedling bed transfer equipment pushing the seedling bed with bearing wheels on the rail for interconnecting each working process by a pneumatic cylinder was made and examined. The examined transfer force to push the seedling bed with a weight of 178.9 N by the pneumatic cylinder with length of 60 cm and section area of 5 $cm^2$ was measured by experiments. The examined transfer forces was compared with theoretical ones calculated by the theoretical formula derived from dynamic system analysis according to the number of the seedling bed and pushing speed of the pneumatic cylinder head at no load. The transfer function of the equipment with the input variable as the pushing speed $V_{h0}$(m/s) and the output variable as the transfer force f(t)(N) was represented as $F(s)=(V_{h0}/k)(s+B/M)/(s(s^2+Bs/M+1/(kM))$ where M(kg), k(m/N) and B(Ns/m) are the mass of the bed, the compression coefficient of the pneumatic cylinder and the dynamic friction coefficient between the seedling bed and the rail, respectively. The examined transfer force curves and the theoretical ones were represented similar wave forms as to use the theoretical formular to design the device for the seedling bed transfer. The condition of no vibration of the transfer force curve was $kB^2>4M$. The condition of transferring the bed by the repeatable impact and vibration force according to difference of transfer distance of the pneumatic cylinder head from that of the bed was as $Ce^{-\frac{3{\pi}D}{2\omega}}<-1$, where ${\omega}=\sqrt{\frac{1}{kM}-\frac{B^2}{4M^2}}$, $C=\{\frac{\frac{B}{2M}-\frac{1}{kB}}{\omega}\}$, $D=\frac{B}{2M}$. The examined mean peak transfer force represented 4 times of the stead state transfer force. Therefore it seemed that the transfer force of the pneumatic cylinder required for design of the push device was 4Bv where v is the pushing speed.

• Korean Journal of Agricultural Science
• /
• v.5 no.2
• /
• pp.49-55
• /
• 1978

In order to get healthy seedling of rice suitable for rice transplanter, the growing characteristics of the seedling grown under different growing days and sowing densities were invesigated and the results obtained were summarized as follows; In the 20 days old seedling, the difference of growing state of seed ling and its characteristics between the two types of nursery bed was not found, but for the 30 days old seedling, both of the crop growth rate and the relative growth rate on the band-type nursery bed appeared higher than those on the mat-type nursery bed. And also, "the dry weight, the content of cardohydrate and the ratio of dry weight to plant height of the seedling grown on the band-type nursery bed were much higher than those on the mat-type nursery bed, however the amount of difference of seedling characteristics between two types of nursery bed was decreased for 40 days old seedling and leaf number was not increased. The amount of the seedling growth was increased with less density of sowing and for the difference between the higher and the less density, the difference getting bigger with the longer nursery days. The maximum density of sowing was approximately 200cc per nursery case on the band-type nursery bed and 250cc per nursery case on the mat-type nursery bed. It was seemed that the growing uniformity of the seedling grown on the mat-type nursery bed was better than that on the band- type nursery bed, As the coefficient of variation of the plant height and the leaf numbers of the seedling grown on the band- type nursery bed was higher than that on the mat-type nursery bed.