• Analytical Science and Technology
• /
• v.8 no.4
• /
• pp.427-434
• /
• 1995

Inductively coupled plasma mass spectrometry combined with the isotope dilution method is used for the determination of lithium. The isotope dilution method is based on the addition of a known amount of enriched isotope (spike) to a sample. The analyte concentration is obtained by measuring the altered isotope ratio. The spike solution is calibrated through so called reverse isotope dilution with a primary standard. The spike calibration is an important step to minimize error in the determined concentration. It has been found essential to add spike to a sample and the primary standard so that the two isotope ratios should be as dose as possible. Since lithium is neither corrosive nor toxic, lithium is used as a chemical tracer in the nuclear power plants to measure feedwater flow rate. 99.9% $^7Li$ was injected into a feedwater line of an experimental system and sample were taken downstream to be spiked with 95% $^6Li$ for the isotope dilution measurements. Effects of uncertainties in the spike enrichment and isotope ratio measurement error at various spike-to-sample ratios are presented together with the flow rate measurement results in comparison with a vortex flow meter.

• Journal of the Korean Home Economics Association
• /
• v.17 no.4
• /
• pp.35-42
• /
• 1979

The effects of salt concentration on the qualities of cooked egg preparations were evaluated. Diluted egg samples which contained different amounts of slat were prepared by diluting whole egg fluid with rice washing, anchovy stock , or distilled water. After heating them rapidly, hardness, gel strength, and amount of syneresis were determined along with the performance of sensory test. the pH of the diluted eggs also measured before heating. Results obtained from these experiments are summarized in the following. 1. The pH of whole egg, egg yolk, and egg white was 7.32, 6.31, and 8.41 , respectively. 2. The pH whole eggs after addition of diluting solutions and salt showed a little differences over the whole salt concentration as follows. distilled water dilution > anchovy stock dilution > rice washing dilution 3. The hardness and gel strength of cooked samples were increased with the increase of salt concentration in the range of low salt concentrations of all diluting solution. These physical properties marked maximal values at salt concentration of 3% and then decreased as salt concentration increased. 4. Amount of syneresis decreased as salt concentration increased regardless of all diluting solutions used. 5. In sensory test, 1% salt concentration were scored good by the panel members regardless of diluting solutions which showed no significant difference among three diluting solutions.

• 한국기계연구소 소보
• /
• s.19
• /
• pp.31-42
• /
• 1989

To investigate design factors of dilution ventilation system, numerical analysis of air contamination flow and concentration distribution have been made, by using the low Reynolds number turbulent model. And flow visualization and measurement of particle concentration for that model also have been made. By comparing of these results we have secured the essential data for the adequate counterplan of dilution ventilation system. The results of this study are as follows: 1) Inlet should be located near the wall for the prevention of the formation of the recircula¬tion zone. 2) In case of natural exhaust, air contamination flow is driven to the far outlet from the inlet. 3) It is favorable for dilution to make turbuence as much as possible.

• Korean System Dynamics Review
• /
• v.6 no.1
• /
• pp.5-15
• /
• 2005

This paper investigates psychological differences between constructors and interpreters of causal maps. This paper argues that dissipation effects and dilution effects applies to those who are to interpret causal maps not to those who construct them. Dissipation effects are psychological tendency that people perceive causal effect as weak as the number of causal links increases. Dilution effects occur when people undervalue the strength of causal relation as the number of causal variables increases. Experimental results show that concentration effects opposite to the dissipation effects and dilution effects explain more correctly the perception of constructors of causal maps. This paper points out that this asymmetric psychological tendencies between constructors and interpreters of causal maps is the psychological source of the communication problems between systems thinkers and their clients.

• Microbiology and Biotechnology Letters
• /
• v.17 no.6
• /
• pp.629-633
• /
• 1989

In the continuous reactor, the hydrogen production rate and residual glucose concentration were increased with increase of input glucose concentration, dilution rate, and recycle rate. The maximum production rate was 91 mL/Lㆍh at dilution rate 0.4/h, input glucose concentration 5.4g/L, and recycle rate 70/h in this experimental range.

• KSBB Journal
• /
• v.7 no.4
• /
• pp.258-264
• /
• 1992

The rheological characteristics of the ethanol fermentation broth were pseudoplastic when the yeast concentration was above 150g/L. From the viewpoint of rheological properties, the cell concentration below 150g/L was recommended for ethanol fermentation. Since the cell floc was formed at the cell concentration of 100 g/L, yeast cells were not much plugged in the pores of the membrane. The cell concentration above 100g/L was desirable when considering the permeability of the membrane. Since ethanol productivity was the highest when the cell concentration was 130 g/L in cell recycled ethanol fermentation. The optimal dilution rate was determined at 1.3 h-1 at constant cell mass of 130g/L. At this dilution rate, the ethanol productivity and glucose conversion ratio ware 80 g/L$\cdot$h and 0.94, respectively.

• Microbiology and Biotechnology Letters
• /
• v.23 no.6
• /
• pp.717-722
• /
• 1995

Using a flocculating Saccharomyes cerevisiae CA-1, an air-lift reactor equipped with a modified settler was used for ethanol fermentation. The effects of conditions such as aeration rate, initial glucose concentration, and dilution rate were studied using the air-lift reactor. In batch fermentation, optimum aeration rate was 0.5 vvm. In continuous fermentation, aeration rate and initial pH were fixed 0.5 vvm and 4.5, substrate concentration and dillution rate were changed 10-15% and 0.1-1.3. The maximum ethanol productivity was shown to be 20.4 g/l$\cdot $h in 10% glucose and 0.7 h$^{-1}$ dilution rate., and optimum operation condition considering the ethanol productivity and glucose utilization ratio was 0.5 h$^{-1}$ dilution rate in 10% glucose concentration.

• KSBB Journal
• /
• v.8 no.3
• /
• pp.243-255
• /
• 1993

In this study, it was observed that hydrogen Productivity varied with stirrer speed, bead radius, input glucose concentration and dilution rate in a continuous stirred tank reactor in which immobilized R. rubrum KS-301 was used as a hydrogen-producing bacterium The mass transfer resistance due to cell immobilization was also studied. In order to estimate an effectiveness factor, Des of glucose was first obtained, which was subsequently represented by the correlation equation between Dos and Xb, As a result external mass transfer resistance could be neglected for stirrer speeds greater than 400rpn With bead radius increasing, the hydrogen productivity and internal effectiveness factor decreased. With input 91ucose concentration increasing, the hydrogen productivity and interval and external effectiveness factor increased. Although an Internal effectiveness factor was not affected, hydrogen productivity Increased with dilution rate increasing. An overall effectiveness factor remained nearly constant for the dilution rates investigate4 but increased with input 91ucose concentration increasing.

• KSBB Journal
• /
• v.4 no.2
• /
• pp.185-190
• /
• 1989

Semicontinuous alcohol fermentation of Jerusalem Artichoke by K. fragilis CBS 1555 was performed to investigate the effect of the effective dilution rate and influent sugar concentration to the ethanol concentration and alcohol productivity at steady state. When the time interval for the replacement of fresh influent with fermentation broth was less than or equal to 1 hr, the effective dilution rate was found out to be equal to the specific growth rate. Wash out was not occurred until the effective dilution rate, 0.425 hr-1, and the maximum alcohol productivity was around 5.5 g/1·hr. In this case, the effective dilution rate was 0.25 hr-1 and the influent sugar concentration was distributed from 85 g/l to 135 g/1.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.6
• /
• pp.410-418
• /
• 2001

The effects of several variables on the refolding of hen egg white lysozyme have been studied, Lysozyme was denatured in both urea, and guanidine hydrochloride(GuHCl), and batch refolded by dilution (100 to 1000 fold) into 0.1 M Tris-HCI, pH 8.2 mM EDTA 3 mM reduced glutathione and 0.3 mM oxidised glutathions. Refolding was found to be sensitive to temperature, with the highest refolding yield obtained at 50$\^{C}$. The apparent activation energy for lysozyme re-folding wasf ound to be 56kJ/mol, Refolding by dilution results in low concentrations of both de-naturant and reducing agent species. It was found that the residual concentrations obtained dur-ing dilution(100-fold dilution:[GuHCI]=0.06 mM, [DTT]=0.15 mM) were significant and could inhibit lysozyme refolding. This study has also shown that the initial protein concentration (1-10mg/mL) that is refolded is an important parameter. In the presence of residual GuHCl and DTT higher refolding yields were obtained when starting from higher initial lysozyme concentra-tions. This trend was reversed when residual denaturant components were removed from the re-folding buffer.