• 설비공학논문집
• /
• 제18권5호
• /
• pp.410-417
• /
• 2006

The present study predicted the effect of the flow rate of coolant on the absorption performance of a vertical falling film type absorber Heat and mass transfer peformances were numerically investigated. The exit temperatures of solution and coolant were decreased as the flow rate of the coolant was increased at the film Reynolds number of 100. The absorption mass flux was increased and then decreased as the distance from the inlet of the absorber was increased. The distance showing the maximum absorption mass flux was ranged from 0.3 to 0.5m. The heat flux and the absorption mass flux were increased and then slowly decreased as the flow rate of the coolant was increased. The maximum values were obtained at the flow rate of coolant of 2.0L/min.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제13권3호
• /
• pp.158-166
• /
• 2005

The present study investigated experimentally and numerically the enhancement of absorption performance due to the waviness of falling film in the vertical absorber tube. The momentum, energy and mass diffusion equations were utilized to find out temperature and concentration profiles at both the interfaces of liquid solution and refrigerant vapor and the wall. Flow visualization was performed to find out the wetting characteristics of the falling film. The maximum heat transfer coefficient was obtained for the wavy flow using spring as an insert device through both numerical and experimental studies. Based on the numerical and experimental results, the maximum absorption rate was found for the wavy-flow using spring as the insert device. The differences between experimental and analytical results ranged from $5.0\;to\;25\%\;when\;Re_j>100$.

• 설비공학논문집
• /
• 제17권9호
• /
• pp.830-838
• /
• 2005

The present study investigated the optimization of the absorption performance of the vertical absorber tube with falling film by considering heat and mass transfer simultaneously. Effects of film Reynolds number, geometric parameters by insert device (spring) and flow pattern on heat and mass transfer performances have been also investigated. Especially, effects of coolant flow rate and the flow pattern by geometric parameters has been observed for the total heat and mass transfer rates through both numerical and experimental studies. Based on both predicted values, the optimal coolant flow rate was predicted as 1.98 L/min. The maximum absorption rate of the spring inserted tube was increased by the maximum of $20.0\%$ than those for uniform film of bare tube. Average Sherwood numbers and Nusselt numbers were increased as Reynolds numbers increased under the dynamic and geometric conditions showing the maximum absorption performance.

• 한국환경보건학회지
• /
• 제22권3호
• /
• pp.49-55
• /
• 1996

Water parsley(Oenanthe javanica(Blume) DC) was raised with varying population density(S) in the laboratory aquarium unit to determine the growth equation. The population density was measure after 7 days. The resultant growth curve was well fit to the equation 1/S = A+B (1/S0) with a high correlation coefficient ($R^2$ = 0.999). The maximum specific absorption rate was $9.011 \times 10^{-5}$ kg $NO_x-N/kg$ water parsley$\cdot$day and $1.31 \times 10^{-5}$ kg $PO_4-P/kg$ water parsley$\cdot$day when the average population density was $2.62 kg/m^2$. The relationship between population density and nutrient absorption rate, the absorption rate of $NO_x-N$ was 5.04~5.24 mg/l$\cdot$day when the population density was $7.51~10.0 $mg/m^2\cdot day$ and the absorption rate of $PO_4-P$ was 0.56~0.78 mg/l$\cdot$day when the population density was 5.02~10.0 $kg/m^2\cdot day$. Taking into account the nutrient absorption rate and growth rate, the population density between $7.0 kg/m^2\cdot day$ and $8.0 kg/m^2 \cdot day$ was selected. The removal rate of nutrient was investigated after 7 days culture. Removal rate of $NO_x-N$ was 95.6~99.95% with initial concentration of 35 mg $NO_x-N/l$, and the removal rate of $PO_4-P$ was also high, indicating 80.24~98.9% with initial concentration of 5.95 mg $PO_x-P/l$.

• Journal of the Korean Wood Science and Technology
• /
• 제12권2호
• /
• pp.10-19
• /
• 1984

The $3{\times}3{\times}30$ ($cm^3$) sized lumbers of Populus alba-grandulosa L. were treated with four fire-retardant solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate and aluminium chloride for 1, 15, 30, and 60 minutes and 1, 3, and 7 days. Thereafter they were air-dried and burned at high temperature about $1,800^{\circ}C$ and for short time of five minutes. This study estimated the relationship between absorbed chemical amounts and rate of weight loss or residual bending strength of these burned lumbers. The results were as follows: 1) In absorption amount of fire-retardant chemicals, diammonium phosphate showed the largest, aluminium chloride the smallest, but monoammonium phosphate and ammonium sulfate showed similar level. 2) The absorption amount of chemicals was decreased with the increase of specific gravity in the same species except aluminium chloride. 3) The rate of weight loss was decreased as the absorption amount of chemicals increased, especially monoammonium phosphate was most effective. 4) The MOR value of the residual bending strength was increased as the absorption amount of chemicals increased and especially monoammonium phosphate showed the most efficient effect. 5) Aluminium chloride showed more striking increase of MOR value of residual bending strength with the increase of absorption amount than any other chemical, therefore its MOR value was similar to the maximum MOR value of the most effective monoammonium phosphate. 6) The correlation between weight loss and MOR value of the residual bending strength was negative and aluminium chloride showed the most striking negative relation, but the others showed similar trends. 7) The correlation between work to proportional limit and absorption amount of chemicals was positive and the degree of increase in work to proportional limit was most in aluminium chloride, and the next, in monoammonium phosphate and diammonium phosphate in turn. 8) The correlation between work to maximum load and absorption amount of chemicals showed positive and diammonium phosphate revealed the best result and aluminium chloride showed better results than other two chemicals.

• 설비공학논문집
• /
• 제6권3호
• /
• pp.175-181
• /
• 1994

This paper deals with the correlation of absorption rate in absorber and evaporation rate in evaporator. The evaporator consists of a copper tube of 10mm dia, and 600mm long and chilled water flowing through the tube is fed by the chilled water circulator. The flowrate of LiBr-water solution in the absorber plays a significant role in determining the magnitude of the heat transfer rate from chilled water to refrigerant There exists a flowrate of solution which has a maximum value of heat transfer. It is interesting to note that the absorption rate of absorber increases with increasing the heat transfer rate of the evaporator. Also, absorption rate increases with evaportation rate, and the ratio(the former/the other) depends on the inlet temperature of LiBr-water solution in the absorber. The heating capacity in the absorber is higher than the refrigerating capacity in the evaporator.

• The Journal of the Acoustical Society of Korea
• /
• 제25권1E호
• /
• pp.14-19
• /
• 2006

Ultrasonic absorption and velocity spectra in bovine serum albumin (BSA) aqueous solutions have been measured at $20^{\circ}C$ over the frequency range 0.2-3 MHz in the pH range 1.5-13.2. The high-Q ultrasonic resonator and pulse-echo overlap methods were used. At acid pH's, excess absorption over that of pH 7 was explained by double relaxation. The pH dependences of the relaxation frequency and maximum absorption per wavelength, showed that the relaxation at about 200 kHz was related to the expansion of molecules and that about 3 MHz resulted from the proton transfer reaction of carboxyl group. At alkaline pH's, the excess absorption was explained by double relaxation. The relaxation at about 300 kHz was associated with a helix-coil transition, and that about 3 MHz was attributed to the proton transfer reaction of phenolic group. The rate constants and volume changes associated with these processes were estimated.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 추계 학술논문 발표대회
• /
• pp.58-59
• /
• 2019

Data on basic properties are needed due to the increased interest of insulation materials, but In Korea, there are fewer data related to the basic properties of insulation. so the absorption rate was measured every seven days by selecting some of the insulation among insulation materials to provide basic data on absorption rates among basic properties. Measured over 43 days, both absorption and weight showed the highest PF levels, other insulation is judged to have almost reached the maximum absorption rate. PF is still an increasing trend and requires constant observation.

• 대한방사선기술학회지:방사선기술과학
• /
• 제8권2호
• /
• pp.77-81
• /
• 1985

In this experiments the operation of the Geiger-Mueller tube is investigated by measuring the relationship between the count rate and the applied voltages, The length and slope of the plateau are characteristic of the tube. In our experiments, the average plateau length of the tube is extend for about 100 [V] and the slope 0.017 [%/V]. For normal counting purposes the working voltage is usually selected at value about 50 volts larger than the threshold of the plateau. To investigate the absorption of beta particles by matter. We performed an absorption experiments by using the Al absorber and Sr-90 ($0.125{\mu}Ci$) beta source. The maximum range of the beta radiation can be determined by visual extrapolation of the curve after subtraction of the constant background-rate and the maximum beta energy 2.09 [MeV] can be calculated from the range using an experimental relation.

• Archives of Pharmacal Research
• /
• 제11권3호
• /
• pp.185-196
• /
• 1988

The inflence of hydrophilic vehicles on percutaneous absorption rate of griseofulvin was studied using intact skin of full thickness of hairless rat. The in vitro absorption rates were used as the characteristics for deciding the optimum formula of ointment vehicles. The optimum formula of vehicle compositions for maximum absorption rate was obtained from the polynomial regression equation and the two graphical techniques, contour graph and partial derivative graph. It was composed of sodium lauryl sulfate (1.65 W /W%), white petrolatum (16.5 W /W%), propylene glycol (12.0 W /W%), and stearyl alcohol (19.6W /W%). The experimental value obtained from the optimum formula and the prediction value were 33.99 and 33.87 ${\mu}g/\sqrt{min}$, respectively. From these results, it was believed that optimum formula for semisolid dosage forms could be obtained from the application of the optimization technique used in this study.