• The Korean Journal of Malacology
• /
• v.21 no.1
• /
• pp.41-46
• /
• 2005

A series of radiotracer studies were conducted to evaluate the influence of water temperature and/or body size on the clearance rates and uptake rates of Cd, Se and Zn in the Asiatic clam, Corbicula fluminea, Asian clam Potamocorbula amurensis and Balthic clam, Macoma balthica. Uptake rates of Cd, Se and Zn were estimated simultaneously with clearance rate of clams under 3 different water temperature conditions (5, 13 and $21^{\circ}C$). The weight specific clearance and metal uptake rates of P. amurensiswere increased with temperature, however, no consistent temperature effect was observed for the other clams. The variation of uptake rates of Cd, Se and Zn along with temperature or body size in each clam species was well associated with clearance rates. The inter-species as well as the intra-species difference of metal uptake rates could be well explained by the variation of clearance rates of clam individuals.

• The Korean Journal of Nuclear Medicine
• /
• v.3 no.2
• /
• pp.49-54
• /
• 1969

The present study has been undertaken to analyze scan manifestations in obstructive jaundice. Scan changes were cprrelated with the duration of jaundice. In addition, clearance rates of trace dose of colloidal radiogold were assessed in each case. The materials were consisted of 19 cases with surgically and/or histopathlogically verified obstructive jaundice from various causes including common duct stone, empyema of the gall bladder and carcinoma of the pancreas head etc. Blood clearance rates of colloidal $^{198}Au$ were determined after the injection of 8 uCi by simple geometrical drawing of recorded strip charts. Scan was performed following additional injection of the same radiogold. In 16 out of 19 cases, the scan revealed rather typical "arborifrom" mottlings around the porta hepatis. The intensity and appearance of such mottlings on the scan was related with the duration of jaundice and level of serum bilirubin and alkaline phosphatase. The blood clearance rates remained to be within normal range in 74 percent of the patients. In the remaining 26 percent, clearance rates ranged between 4.1 and 6 minutes. It is concluded that the association of "arboriform" mottlings and normal or mildly delayed clearance rates in the patients with jaundice is characteristic of obstructive changes in the biliary system.

• Korean Journal of Environmental Biology
• /
• v.30 no.4
• /
• pp.349-354
• /
• 2012

To evaluate the biological response of sea squirt Halocynthia roretzi with different body size to heavy metals and its suitability for ecotoxicity assays, the effects of Cr, Cu and Zn on its clearance and oxygen consumption rates were investigated. Clearance and oxygen consumption rates of H. roretzi with various body sizes were calculated at different metal concentrations. Both clearance and oxygen consumption rate were negatively correlated with body sizes. Clearance rate of H. roretzi decreased gradually with increasing concentration of heavy metal, the decreasing rate was in an order of Cr>Cu>Zn. The oxygen consumption rate first increased at low metal concentration (below $100{\mu}g\;L^{-1}$) and then decreased rapidly with increasing metal concentrations. The decreasing rate was in an order of Cu>Cr=Zn. There was a trend that the clearance rate and oxygen consumption rate decreased drastically under a concentration of $400{\mu}g\;L^{-1}$, and then decreased smoothly when the metal ion concentration increased continually. So the oxygen consumption and clearance rate at a concentration of $400{\mu}g\;L^{-1}$ Cu could be thought as a suitable biological tool for exotoxicology analysis.

• International Journal of Fluid Machinery and Systems
• /
• v.6 no.3
• /
• pp.113-120
• /
• 2013

While performing numerical simulations, it is general industrial practice to neglect the clearance gap between the impeller and the inlet duct. In the present work, the effect of clearance gap on the performance of an industrial sized centrifugal blower is simulated for two volutes of width ratios and various flow coefficients. The results show that the clearance has a positive effect at low mass flow rates. This is observed in the pressure rise (1.3%) as well as in efficiency (0.7%). At higher mass flow rates, it has a negative effect with a drop in efficiency of 1% and pressure drop of about 1.4%. The effect of clearance gap on volute with higher width ratio is smaller when compared with the volute with smaller width ratio.

• The Korean Journal of Malacology
• /
• v.17 no.2
• /
• pp.95-104
• /
• 2001

To determine optimal conditions for measurement of the clearance rate in feeding experiment of an intertidal bivalve Glauconome chinensis, effects of starvation, extent of mixing at subsampling, and initial prey concentration were assessed. Experiments were conducted separately for each condition with different treatments. Two-way ANOVAs showed that there were significant differences in clearance rates among different starvation periods (p<0.001), extents of mixing (p = 0.005), and prey concentrations (p < 0.001). Starvation for 1 or 2 days gave rise to 2 to 3-fold increase in the clearance rate. After starvation for 5 days, the clearance rate decreased seriously, implying loss of physiological status. It is suggested that animals should be fed during acclimation. The differences of the clearance rates between gentle and vigorous mixings were significant, but the differences were smaller than that among different incubation times. It was found that vigorous mixing is not necessary. The effect of initial prey concentration was great. However, optimal prey concentration could not be determined at any fixed value. Experiments with multiple concentrations of algal prey are recommended. Optimal incubation time for measurement of the clearance rate of G. chinensis was determined to be 2-4 hours.

• Korean Journal of Environmental Biology
• /
• v.22 no.3
• /
• pp.438-445
• /
• 2004

A radiotracer study was conducted to evaluate the influence of body size and temperature on the uptake rates of Cd, Se and Zn in the California mussel, Mytilus californianus. Uptake rates of Cd, Se and Zn were determined simultaneously with clearance of the mussels with 3 different size classes (0.07, 0.24 and 0.73 g flesh dry weight $individual^{-1})$ and at 4 different temperatures (3, 8, 13 and $21^\circ{C})$. The weight-specific uptake rates of 3 elements significantly decreased with body size, but increased with temperature. Simultaneously measured clearance rates of mussels were closely associated with metal uptake rates. The significant association of clearance rates and metal uptake rates of mussels emphasizes the importance of functional role of water pumping activity in the metal uptake process in filter-feeding organisms.

• Journal of Ecology and Environment
• /
• v.37 no.4
• /
• pp.225-229
• /
• 2014

Feeding behavior of Temora turbinata was investigated through laboratory experiments with special emphasis on its food preference and consequent clearance rate on diatom and microbial components given as common natural food assemblage of coastal area (Uchiumi, Uwa Sea, Japan). Among available prey items, T. turbinata showed the highest clearance rate for Thalassiosira spp. ($0.23{\pm}0.08L\;Temora^{-1}day^{-1}$) followed by Chaetoceros spp. ($0.11{\pm}0.03L\;Temora^{-1}day^{-1}$), but clearance rates for other diatom, Nitzschia spp. was lower (0.03 to $0.07L\;Temora^{-1}day^{-1}$). Bacterial abundances showed no response against 24-h feeding of T. turbinata. Feeding of T. turbinata on heterotrophic nanoflagellates (HNF) was apparent when clearance rates of T. turbinata on diatoms were relatively low, but T. turbinata did not consume HNF as well as ciliates with Thalassiosira spp. of which clearance rate was highest. The results suggest that HNF and ciliates are possible supplementary prey item for T. turbinata, but their contribution as food sources can be limited by the presence of other prey items such as preferable diatom species.

• 유체기계공업학회:학술대회논문집
• /
• 1998.12a
• /
• pp.240-247
• /
• 1998

Leakage vortices formed near blade tip causes an increase of total pressure loss near casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated with varying tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the less distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and aprroximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.

• Journal of Power System Engineering
• /
• v.20 no.6
• /
• pp.34-39
• /
• 2016

This paper is the numerical study on the correlation of leakage by the variation of inlet pressure and clearance in hydrostatic bearing. The main goal of this study is to apply to the design of hydro system the results that the pocket pressure and the leakage rate according to the inlet pressure and the clearance between piston and cylinder tube. Because the hydrostatic bearing in hydraulic cylinder has the narrow rectangular channel between piston and cylinder tube, so to verify the numerical scheme, it has been compared with the experimental results of Brackbill and Kandlikar. The pressure data of numerical results inside narrow rectangular channel correlate was showed a good agreement with experimental results, thereby the numerical scheme was applied to the real model that is a hydraulic cylinder with the hydrostatic bearing. In conclusion, the pressure differences between inlet and pocket were shown within 3%. Leakage rates were showed rapidly increased pattern between about 4.5 and 6.7 times because the section area to calculate the leakage rates were proportioned to a square of diameter. The correlation equation was calculated among the inlet pressure, the clearance and the leakage rate by using the linear regression.

• The KSFM Journal of Fluid Machinery
• /
• v.2 no.1 s.2
• /
• pp.73-80
• /
• 1999

Leakage vortices formed new blade tip causes an increase of total pressure loss near the casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of the tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated by varying the tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the loss distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and approximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.