• Journal of Environmental Science International
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• v.11 no.3
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• pp.263-269
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• 2002

This study was conducted to know the removal characteristics of ammonia nitrogen by commercially available cation exchange resins. Eight acidic cation exchange resins were investigated in batch reactors. Among them, the most effective resin for ammonia removal in solution was PK228, which was a strong acidic resin of $Na^{+}$ type. PK228 was compared with activated carbon and natural zeolite. The effects of cation exchange capacity, ammonia concentration, resin amount, temperature and pH on ammonia removal by PK228 were investigated in batch reactor, and the effect of effluent velocity in continuous column reactor. Strong acidic resins of porous type were more effective than week acidic resins or gel type resins for ammonia removal in solution. PK228 was more effective than activated carbon and natural zeolite for ammonia removal in batch reactor. With increasing initial ammonia concentration, the amount of ammonia removed by PK228 increased, but the proportion of removed ammonia to initial ammonia concentration decreased. The effect or temperature on ammonia removal by PK228 was very slight. The ammonia removal to acidic solution was more effective than that at basic solution. With decreasing effluent velocity of solution through column, breakthrough point extended, and ammonia removal capacity increased.d.

• Journal of the Korea Furniture Society
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• v.18 no.4
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• pp.275-281
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• 2007

This study was carried out to know bending process property of bentwood by treatment methods such as microwave and ammonia solution treatment. Bentwood processing was operated on bending-jig form with 60mm and 100mm radius of curvature (ROC). The species was used to Korean red pine (Pinus densiflora). No significant difference was shown in bentwood processing method on ROC. In treatment method, ammonia solution treatment for bentwood was better in dimensional stability and working ability than that of microwave treatment. However, bentwood stress was reduced with ammonia solution treatment. Color of bentwood surface appearance has a dark tendency in ammonia solution treatment. But it seems to beautiful effect of apparent annual ring is rising esthetically by ammonia solution treatment. To utilize wood as a exterior material for living amenity, it has to be closely examined from various angles including surface property, degree of swelling and shrinkage, drying state, retaining strength, durability, safety, and insect damage.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.3
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• pp.287-292
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• 2004

An experimental investigation was carried out to study the performance of a bubble pump for the diffusion absorption refrigerating system. Ammonia was used as the refrigerant and the helium was charged in order to balance the pressure between the low and high pressure side. As experimental variables, the concentration of ammonia charged into system, heat input, and the pressure of helium were selected. Experimental results show that the generation rate of ammonia vapor and the circulation rate of diluted ammonia solution were increased as the heat input increases, but the ratio of the solution to vapor flow rate was decreased. The generation rate of refrigerant vapor and the circulation rate of diluted ammonia solution increased as the system pressure decreased. Finally under the condition of 25 bars, the concentration of rich ammonia solution was not affected by the generation rate of ammonia vapor and the circulation of diluted ammonia solution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.1034-1041
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• 2001

A numerical model which simulates the flow boiling process of the ammonia/water solution within a plate type generator for ammonia/water absorption refrigerators was developed. The ammonia/water solution flows downward under gravity and the ammonia/water vapor generated by flow boiling flows upward. The heating medium flows counter to the ammonia/water solution. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phases were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the heating medium inlet temperature, the mass flow rate of the heating medium and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

• Bulletin of the Korean Chemical Society
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• v.2 no.3
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• pp.90-96
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• 1981

The significant structure theory of liquids has been successfully applied to the sodium ammonia solution. In applying the theory to sodium ammonia solution, we assumed there were four species in solution, i.e., sodium cation, solvated electron, triple ion, and free electron and equilibria existed between them. Based on these assumptions, we set up the model explaining the anomalous properties of sodium ammonia solution. The partition function for sodium ammonia solution is composed of the partition functions for the above four species and also for the Debye-Huckel excess free energy term. Agreements between calculated and experimental values of the thermodynamic quantities, such as molar volume, vapor pressure, partial molar enthalpy and entropy, and chemical potential as well as viscosity are quite satisfactory.

• Journal of the Korean Wood Science and Technology
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• v.18 no.2
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• pp.25-35
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• 1990

To investigate the effects of swelling treatment by ammonia on characteristics of carboxymethy1cellulose(CMC) and CMC solution, the domestic kraft pulp pretreated with 5%, 10%, 15% and 20% $NH_4OH$ solution, was carboxymethylated by the standard method, and then the CMC prepared was tested. The physical properties of CMC and CMC solution, such as degree of substitution, transparency. viscosity, weight increase and solubility, were measured, and the comparison with commercial domestic CMC used as a food additive was done. The results obtained were as follows; 1. In CMC manufactured by standard solvent method, hardwood bleached kraft pulp(LBKP) was more substituted than safwood bleached kraft pulp(NBKP), and viscosity of NBKP was higher than that of LBKP. 2. When ammonia swelling treatment was done, degree of substitution gradually decreased with increasing concentration of $NH_4OH$, and degree of substitution of LBKP decreased with a larger range than that of NBKP. 3. When ammonia swelling treatment was done. transparency of CMC solution from LBKP was hardly effected, but in case of NBKP gradually increased with increasing concentration of $NH_4OH$. 4. When ammonia swelling treatment was done, viscosity of CMC solution was higher than that of CMC solution without ammonia swelling treatment. Especially, CMC of high viscosity could be manufactured in 5%, 10% concentration levels of $NH_4OH$. 5. In CMC manufactured from domestic NBKP, CMC at the range of 0.40 to 0.50 in DS was dispersed easily and quickly dissolved, and CMC at more than 0.50 in DS was dispersed slowly in water solution. 6. In comparison with commercial domestic CMC used as a food additive, CMC manufactured from domestic NBKP was higher in DS, and was lower in viscosity and transparency.

• Journal of the Korean Vacuum Society
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• v.8 no.4B
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• pp.524-529
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• 1999

We deposited diamond phase carbon thin films on Si substrate by the electrolysis of methanol solution. A little amount of ammonia solution was added to increase the current density of the electrolyte. We analyzed films by XRD and SEM. The chemical change of electrolyte during the electrolysis process was characterized by FTIR. We obtained better quality diamond phase carbon films at a lower applying boltage(300V) and temperature ($40^{\circ}C$) by adding ammonia solution to methanol electrolyte. Diamond (111), (220), (311) peaks were shown distinctively in XRD graph. Addition of ammonia solution resulted in lowering the applying bias voltage to 300V and the substrate temperature to $40^{\circ}C$ still maintaining a high current density at 80mA/$\textrm{cm}^2$, which prohibited a great loss of solution from vaporization. Possible change of chemical reaction due to the addition of ammonia solution was also discussed.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.1 s.53
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• pp.107-114
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• 2005

The uncertainty of measurement in quantitative analysis of ammonia by continuous-flow analysis method was evaluated following internationally accepted guidelines. The sources of uncertainty associated with the analysis of ammonia were the weighing of sample, the preparation of extracting solution, the addition of extracting solution into the sample, the reproducibility of analysis and the determination of water content in tobacco, etc. In calculating uncertainties, Type A of uncertainty was evaluated by the statistical analysis of a series of observation, and Type B by the information based on supplier's catalogue and/or certificated of calibration. It was shown that the main source of uncertainty was caused by the volume measurement of 1 mL and 2 mL, the purity of ammonia reference material in the preparation of standard solution, the reproducibility of analysis and the determination of water content of tobacco. The uncertainty in the addition of extraction solution, the sample weighing, the volume measurement of 50 mL and 100 mL, and the calibration curve of standard solution contributed relatively little to the overall uncertainty. The expanded uncertainty of ammonia determination in burley tobacco at $95\%$ level of confidence was $0.00997\%$.

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.798-802
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• 1996

The photochemical decomposition of aqueous ammonia in the absence (saturated with argon) and the presence of O2 (saturated with air or oxygen) has been investigated using 184.9 nm UV light. The decomposition of ammonia depended on the concentration of oxygen in the solution. With increasing the concentration of oxygen, the decomposition of ammonia diminishes. Hydrazine is found the major product from the irradiation. In the presence of oxygen, hydrogenperoxide was also produced. The product yields depended also on the concentration of oxygen in the solution. The initial quantum yield of the products and of the ammonia decomposed were determined. Probable reaction mechanisms for the reaction were presented from the products analysis.

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.2
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• pp.69-79
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• 2000

Falling film rectification involves simultaneous heat and mass transfer between vapor and solution film. In the present work, the adiabatic rectification process of ammonia-water vapor by the falling solution film on the vertical plate was investigated. The continuity momentum, energy and diffusion equations for the solution film and the vapor mixture were formulated in integral forms and solved numerically, The model could predict the film thickness, the pressure gradient, and the mass transfer rate. The effects of Reynolds number and ammonia concentration of solution and vapor mixture, rectifier length, and the enhancement of mass transfer coefficient in each phases were investigated. The stripping of water in vapor mixture occurred near the entrance of ammonia solution, which imposed the proper size of an adiabatic rectifier. Rectifier efficiency increased as film Reynolds number increased and as vapor mixture Reynolds number decreased. The improvement of rectifier efficiency was significant with the enhancement of mass transfer coefficient in falling film.