• Resources Recycling
• /
• v.16 no.6
• /
• pp.52-60
• /
• 2007

Denitrification from aqueous solution was investigated through patent analysis and electrochemical denitrification experiment. Among several candidates, biological treatment and oxidation/reduction method are mainly discussed. Recently, patent pending concerning to electrochemical treatment is increasing. Based on basic electrochemical study, total nitrogen was removed up 47% by 1-hour galvanostatic electrolysis with Fe cathode and Pt anode. More applicable technique to industry could be mentioned combination of two or more technologies suitable to waste water characteristics. In the case of small and concentrate effluent, combination of chemical and electrochemical treatment would be recommendable because nitrate could be easily converted to nitrite by chemical treatment, and in that case denitrification by electrolysis becomes more efficient and metal ions from chemical treatment can be recovered during electrolysis.

• Journal of Adhesion and Interface
• /
• v.13 no.2
• /
• pp.64-72
• /
• 2012

Vinyl acetate/alkyl acrylate copolymers were prepared by water-born emulsion copolymerization according to the compositional change of vinyl acetate and various alkyl acrylates such as methyl acrylate (MA), ethyl acrylate (EA), and n-butyl acrylate (BA). Ammonium persulfate (APS) was used as an initiator and poly(vinyl alcohol) (PVA) was used as a protective colloid. The significant result was described as follows. The activation energy determined by an isothermal analysis in the temperature region between $100{\sim}200^{\circ}C$ of the copolymer had the order of PVAc/PMA > PVAc/PEA > PVAc/PBA. The peel strengths before and after the plasma treatment were the order of PVAc/PMA > PVAc/PEA > PVAc/PBA.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.3
• /
• pp.144-151
• /
• 2010

In this study, it is investigated the mechanical chemical properties of cement matrix using phosphogypsum and kaolin as a admixture for the substitutive materials to silica fume which is so expensive. For the test, phosphogypsum is modified as dihydrate, hemihydrate, type III anhydrite, and type II anhydrite, respectively and furnaced kaolin at $900^{\circ}C$ was also manufactured into meta kaolin by air cooling and water cooling method. The chemical characteristic and mechanical properties of various type of blended cements contained above mentioned gypsum and meta kaolin materials analyzed and compared with those characteristics of cement matrix with silica fume. From the test, the cement mixed meta kaolin made in water cooling has more excellent quality than other material.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.2
• /
• pp.172-175
• /
• 2003

The regression equations of dry weight of planktonic biomass upon physico-chemical characteristics of fifteen ponds in three replicates under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond was obtained after one year of experimental period by using stepwise regression method. Water samples from each of the ponds were analyzed daily. However, the average values were calculated on the basis of 15 day intervals designated as fortnight. In artificial feed supplemented pond the regression of average nitrates on dry weight of planktonic biomass accounted for 71.7% of the variation in biomass. In broiler manure fertilization pond the regression of total nitrogen on dry weight of planktonic biomass held it responsible for more than 74.6% of variation in biomass. In buffalo's manure fertilized pond more than 82% of the variations in biomass were due to total nitrogen. In case of N:P:K (25:25:0) treated pond 66% of the variation in the dry weight of planktonic biomass was due to average nitrates. The control pond showed the dependence of biomass on light penetration. This equation explained more than 62 percent of variation in biomass. Other variables also showed some contribution towards variation in biomass under all the treatments in these regression studies.

• Journal of the Korea Institute of Building Construction
• /
• v.7 no.4
• /
• pp.117-124
• /
• 2007

Focused on the material-related aspect for enhancing the durability of concrete, the present study analyzed the effect of glycol ether admixture, which is a chemical admixture that can compact the structure of concrete by entraining air inside the concrete, on the basic physical properties and durability characteristic of the concrete. In analyzing the results of experiment, we examined the basic physical properties and durability characteristic of concrete according to addition rate based on OPC and selected the optimal addition rate. In addition, with the optimal addition rate, we added glycol ether admixture to concrete, which contained fly ash used as binder and high-performance water reducing agent for reducing the unit quantity, and examined changes in the characteristics of the concrete. According to the result, the optimal addition rate of glycol ether admixture was 3% of the unit quantity of cement, and the addition of binder and chemical admixture did not have a significant effect on unhardened concrete but reduced the air content. In addition, concrete showed resistance performance of around 30% to carbonation and around 40% to drying shrinkage. In addition, as for resistance to freezing and thawing, the relative dynamic modulus of elasticity was over around 85% through atmospheric curing. These performances prove the effect.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.28 no.3
• /
• pp.345-350
• /
• 1983

Collected 38 varieties of colored-soybean seed cultivated under a given cultural conditions were tested in the various chemical compositions and rheological properties in seeds. As it were, protein, fat, carbohydrate, ash and water contents as a chemical contents were studied not only on their statistical variations, but also on interrelationships with their collaborated rheological characteristics; hardness, cohesiveness, elasticity, gumminess and chewiness. For the rheological analysis of the materials, the General Foods Texturometer and typical texturometer curve were used.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.4
• /
• pp.278-283
• /
• 1993

Gimhae series has a high content of jarosite mineral which is evoluted in soils from sediments rich in sulfur. Chemical compositions of jarosite mineral and soil samples were analyzed with water and various extraction solutions to evaluate the pedogenetic processes of the soil. The pH of jarosite mineral and $Bg_3$ horizon are below 4.0 and not much changed after incubation of dry samples rich in jarosite. The pedogentic formation of jarosite was identified through the chemical analysis indicating that cations and anion of K, Na, Al and S are present in abandance in $Bg_2$ and $Bg_3$ horizons.

• Journal of Mechanical Science and Technology
• /
• v.17 no.9
• /
• pp.1358-1370
• /
• 2003

The effects of anode, cathode, and cooling channels for a Proton Exchange Membrane Fuel Cell (PEMFC) on flow fields have been investigated numerically. Continuous open-faced fluid flow channels formed in the surface of the bipolar plates traverse the central area of the plate surface in a plurality of passes such as a serpentine manner. The pressure distributions and velocity profiles of the hydrogen, air and water channels on bipolar plates of the PEMFC are analyzed using a two-dimensional simulation. The conservation equations of mass, momentum, and energy in the three-dimensional flow solver are modified to include electro-chemical characteristics of the fuel cell. In our three-dimensional numerical simulations, the operation of electro-chemical in Membrane Electrolyte Assembly (MEA) is assumed to be steady-state, involving multi-species. Supplied gases are consumed by chemical reaction. The distributions of oxygen and hydrogen concentration with constant humidity are calculated. The concentration of hydrogen is the highest at the center region of the active area, while the concentration of oxygen is the highest at the inlet region. The flow and thermal profiles are evaluated to determine the flow patterns of gas supplied and cooling plates for an optimal fuel cell stack design.

• Food Science of Animal Resources
• /
• v.21 no.3
• /
• pp.208-214
• /
• 2001

This study was conducted to investigate the influence of dietary oriental medicine refuse(OMR) and mugwort powder on physico-chemical characteristics of Korean Native Pork(KNP). KNP were randomly assigned to one of the three dietary treatments : 1) control (commercial feed) 2) T1 (commercial fed supplemented with 10% OMR powder) 3) T2 (commercial feed with 10% mugwort powder). 15 heads(♂) were feed one of the experimental diets for 5 months and slaughtered. In the proximate composition, moisture content showed slightly high in the T1, however, fat content were tended to be high in the control. The heating loss, shear value, WHC (water holding capacity) were not significantly between control and the treatments group. The T1 showed the lowest pH among treatments (P<0.05). In sensory evaluation, juiciness and tenderness of T1 and T2 were higher compared with that of control. Hunter a* did not show any difference among the treatments group. But Hunter L*, b* in treatment group(T1, T2) were higher than that of the control. Oleic acid, linoleic acid and unsaturated fatty acid contents of T1 and T2 were higher than the control. The total amino acid of the control, T1 and T2 were 18.290, 18.177 and 18.942mg%, respectively.

• Journal of the Korean Applied Science and Technology
• /
• v.25 no.1
• /
• pp.32-40
• /
• 2008

1,4-Dioxane is an EPA priority pollutant often found in contaminated ground waters and industrial effluents. Conventional water treatment techniques are limited to decompose this compound effectively. Therefore, an advanced oxidation process system (AOP) was used for the degradation of 1,4-dioxane. This research investigates the effect of adding oxidants, such as ozone, air, and $H_2O_2$ during the UV irradiation of 1,4-dioxane solution. In order to analyze 1,4-dioxane, a modified 8270 method, which is an improved method of U.S EPA 8720, was used. Degradation efficiencies of 1,4-dioxane by only UV irradiation at various temperatures were not significant. However, The addition of oxidants and air bubbling in the UV irradiation system for 1,4-dioxane decomposition showed the higher 1,4-dioxane degradation rate. And, during AOP treatment the tendency of TOC changes was similar to that of 1,4-dioxane decomposition rate.