• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.4
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• pp.147-155
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• 2006

The drag reduction (DR) and heat transfer efficiency reduction (ER) of non-ionic surfactant were investigated as a function of fluid velocity, temperature, and surfactant concentration. An experimental apparatus consisting of two temperature controlled water storage tanks, pumps, test specimen pipe and the piping network, two flow meters, two pressure gauges, a heat exchanger, and data logging system was built. From the experimental results, it was concluded that existing alkyl ammonium surfactant (CTAC Cethyl Trimethyl Ammonium Chloride) had DR of $0.6{\sim}0.8$ at $1,000{\sim}2,000ppm$ concentration with fluid temperature ranging between $50{\sim}60^{\circ}C$. However, the DR was very low when the fluid temperature was $70{\sim}80^{\circ}C$. The new amine oxide and betaine surfactant(SAOB Stearyl Amine Oxide + Betaine) had lower DR at fluid temperatures ranging between $50{\sim}60^{\circ}C$ compared with CTAC. However, with fluid temperature ranging between $70{\sim}80^{\circ}C$ the DR was $0.6{\sim}0.8$ when the concentration level was $1,000{\sim}2,000ppm$.

• Journal of the Korean Geotechnical Society
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• v.37 no.4
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• pp.39-47
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• 2021

Recently, the enzyme-induced carbonate precipitation (EICP) technique has been considered as one of the alternatives to the cement-based soil reinforcing method. However, the problem with the emission of ammonium ion has not been solved. In this study, an experimental study on the EICP without releasing an environmental contaminant (Ze-EICP) is performed using calcium-exchanged zeolite. The results show that the Ze-EICP using calcium-exchanged zeolite reduced the amount of ammonium ions by 96.96% and precipitated almost the same amount of calcium carbonate, compared to the EICP using calcium chloride. In addition, the Ze-EICP shows higher strength improvement rate than the EICP due to densification of zeolite and cementation of calcium carbonate.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.271-276
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• 1998

This experiment was carried out to investigate the changes on nutrient uptake and yields of onion when it was applied with urea and ammonium sulfate as nitrogen fertilizer types; potassium chloride and potasssium sulfate as potassium fertilizer types and lime requirement and phosphorus absorption coefficient controlled 5% as soil improvement index. The variety of onion used was CheonJuHwang and the soil used was Yonggye series in the Jeonnam Muan area. The amounts of N, P and K uptake were higher in the mixed application plot of ammonium sulfate and potassium sulfate than in the plot of urea or potassium chloride. The sulfate content of soil was higher in the period of plant growth than in the harvest stage. The sulfate content of plant was highest in the harvest stage and this content was higher in the stem and in the leaf than in the bulb. The sugar content of onion was 7.43~8.23 Brix content was higher in the large bulb than in the small bulb. The weight of dry matter and the rate of good quality were high in the mixed application plot of ammonium sulfate and potassium sulfate, so the yield of onion was increased 2~6% compared with control.

• Korean journal of food and cookery science
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• v.20 no.2
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• pp.119-125
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• 2004

Effects of various chemical additives and heat treatments were investigated on the wheat flour doughs and breads. Ammonium ferric citrate, Ca-citrate, CaCl$_2$, FeSO$_4$, MgCl$_2$and ZnO were mixed respectively to the flour up to 0.1% of flour dry weight basis. Ammonium ferric citrate and ferric sulfate showed no significant effects on the dough properties and magnesium sulfate, calcium chloride and zinc oxide increased elastic properties and optimum dough mixing time. However, calcium citrate and magnesium chloride showed no significant effects on the dough mixing properties. Most of chemicals were detrimental on the bread volume except MgSO$_4$ and CaCl$_2$. Breads with MgSO$_4$ and CaCl$_2$ retained the equal or slightly higher volume compared to control bread. Crumb and crust colors of breads with addition of chemicals were changed to lighter than that of control bread. L values both of crumb and crust increased with addition of chemicals except Ca-citrate. To inactivate the endogenous enzymes of flour, flour was roasted under electric oven, exposed to UV and microwave. Those heat treatments of flour increased dough stability and produced no dough breakdown after optimum mixing time. However, bread volume of heat-treated flour decreased.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.971-975
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• 2008

This study was to examine the potential disinfection efficiencies of 10 compounds by determining their antimicrobial capacity and ichthyotoxicity. Antimicrobial effects against Vibrio sp., Edwadsiella tarda, Streptococcus sp., and Staphylococcus sp. were tested using 10 different disinfectants; hydrogen peroxide, sodium hypochlorite, chlorine dioxide, povidon iodine, formaldehyde, glutaraldehyde, quaternary ammonium compounds (QACs), didecyl dimethyl ammonium chloride (DDAC), ortho-dichlorobenzen, and copper sulfate. Chlorine dioxide ($ClO_2$) containing 5% $ClO_2$ and copper sulfate had no effects on bactericidal activity, while the other disinfectants resulted in 99.99% bactericidal activity against 4 strains of fish pathogenic bacteria. The ichthyotoxicity of the 10 disinfectants was investigated using 3 kinds of fish species; flounder (Paralichthys olivaceus), rockfish (Sebastes pachycephalus), and black sea bream (Acanthopagrus schlegelii). Median lethal concentration ($LC_{50}$) values of the 10 disinfectants were estimated to determine toxicity ranges of the doses within 24 hr. Among test disinfectant solutions, hydrogen peroxide showed the highest $LC_50$ in flounder (201.3), rockfish (269.7), and black sea bream (139.3 ppm). DDAC revealed the lowest $LC_{50}$ in flounder (2.1), rockfish (1.0), and black sea bream (1.5 ppm). These results suggest that DDAC, quaternary ammonium compounds, glutaraldehyde, and sodium hypochlorite are effective disinfectants for fish and bacterial species examined in this study.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.522-527
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• 2010

Gibberellic acid ($CA_3$) is used in many industries and constitutes the primary gibberellins produced by fungi and bacteria. However, there is no information on $CA_3$ production by Methylobacterium oryzae CBMB20, a novel plant growth promoting bacterium. We investigated the favorable carbon (C) and nitrogen (N) sources and ratios and cultural conditions, such as incubation temperature, pH of the culture medium, and incubation period for the maximum production of $CA_3$ by Methylobacterium oryzae CBMB20. Maximum $CA_3$ production was observed in ammonium mineral salt (AMS) broth supplemented with Na-succinate and $NH_4Cl$ as C and N sources, respectively. The maximum $CA_3$ production was found at the C/N ratio of 5:0.4 g $L^{-1}$. The highest $CA_3$ production was obtained when the bacterial culture was incubated at $30^{\circ}C$ for 96 h at pH 7.

• KSBB Journal
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• v.5 no.3
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• pp.215-221
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• 1990

The solubilization of BSA, pepsin, trypsin and ribonuclease-a in cationic reverse micellar solutions has been investigated. For complete solubilization into reverse micellar solutions, pH values of several pH units above the isoelectric point of each protein were required. Solubilization was observed to decrease with increasing ionic strength of KCI. The size of empty micelles showed no significant change with increasing ionic strength. Trioctylmethyl ammonium chloride (TOMAC) in cyolohexane showed the lowest solubilization for the proteins. The system didodecyl dimethyl ammonium bromide (DDAB)-tetrachloroethylene was capable of solubilizing larger amounts of proteins than the system DDAB-benzene. Cetyl trimethyl ammonium bromide(CTAB)-hexanol-isooctane system showed lower solubilization than DDAB-tetrachloroethylene system, while it had higher Wo value.

• Microbiology and Biotechnology Letters
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• v.15 no.6
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• pp.369-374
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• 1987

A bacterium which grows on D-$\alpha$-Amino-$\varepsilon$-Caprolactam as sole carbon, energy and nitrogen source was isolated from the sludge of industrial areas in Taegu, and identified as Alcaligenes eutrophus. The optimum pH, temperature and concentration of D-$\alpha$-Amino-$\varepsilon$-Caprolactam for the growth were 6.0, 3$0^{\circ}C$ and 0.2% respectively. The bacteria could utilize glucose and fructose as a carbon source, and utilize ammonium chloride, ammonium nitrate, ammonium sulfate and sodium nitrate as a nitrogen source, and utilize L-Iysine and L-glutamate as a carbon and nitrogen source. It was found with thin layer chromatography and polarimeter that D-$\alpha$-Amino-$\varepsilon$-Caprolactam was converted to L-Iysine by the cell-free extracts of Alcaligenes eutrophus A52.

• Journal of the Korean Wood Science and Technology
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• v.12 no.3
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• pp.15-24
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• 1984

The $3{\times}3{\times}30\;cm^3$ sized specimens of Douglas-fir(Pseudotsuga menziesii) and western hemlock(Tsuga heterophylla) in this study were soaked in four fire-retardant solutions of ammonium sulfate, monoammonium phosphate, diammonium phosphate, and aluminium chloride for 1, 24, 72, 168, and 336 hours. Subsequently they were air-dried and burned at high temperature of ca. $1,800^{\circ}C$ and for short time of 5 minutes. This study estimated the relationship between the adsorbed chemicals and the residual weight ratio or residual bending strength of these partly burned lumbers. The results were as follows; 1) In average amount of chemical adsorption, diammonium phosphate showed the largest and aluminium chloride the smallest regardless of species but monoammonium phosphate was larger in Douglas-fir than that of western hemlock. 2) The amount of chemical adsorption was larger in western hemlock than Douglas-fir on the whole. 3) The amount of chemical adsorption was increased with the increase of soaking time but the rate of increase began to decrease at 200hrs. 4) Residual weight ratios showed no difference between species but showed differences among the chemicals treated i.e. monoammonium phosphate, diammonium phosphate, ammonium sulfate and aluminium chloride in turn from the largest to the smallest. 5) MOR values showed linear increase with the increase of residual weight ratios but showed no difference in species and chemicals respectively. 6) In the relationship between amount of chemical adsorption and MOR, only diammonium phosphate showed the curve of secondary degree with significance in Douglas-fir. 7) The MOE value of burned Douglas-fir lumber increased and showed significance of 99% as the adsorbed chemical amount increased, but among the chemicals only monoammonium phosphate showed significance. The MOE value of burned western hemlock lumber didn't show significance. 8) In only Douglas-fir, the correlation between adsorbed chemical amount and work to proportional limit showed significance in only monoammonium phosphate. And in both Douglas-fir and western hemlock, the correlation between adsorbed chemicals and work to maximum load showed significance in monoammonium phosphate.

• Elastomers and Composites
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• v.52 no.4
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• pp.287-294
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• 2017

Nanocomposites based on $SnO_2-Mn$ were synthesized by the reaction of tin (II) chloride dihydrate and manganese (II) chloride tetrahydrate at a molar ratio of 10:1 in the presence of ammonium hydroxide at $80^{\circ}C$. The $SnO_2-Mn$ nanocomposites were stirred with fullerene [$C_{60}$] in a mass ratio of 2:1 in tetrahydrofuran to prepare $SnO_2-Mn-C_{60}$ nanocomposites; these nanocomposites were obtained upon heating the mixture of $SnO_2-Mn$ nanocomposites and fullerene [$C_{60}$] in an electric furnace at $700^{\circ}C$ for 2 h. The synthesized $SnO_2-Mn-C_{60}$ nanocomposites were confirmed through various characterization methods such as X-ray diffraction and scanning electron microscopy. The photocatalytic activities of the $SnO_2-Mn-C_{60}$ nanocomposites were demonstrated by the degradation of the organic dyes BG, MB, MO, and RhB under 254 nm irradiation and evaluated using UV-Vis spectrophotometry.