• Journal of Environmental Science International
• /
• v.21 no.12
• /
• pp.1529-1533
• /
• 2012

The objective of this study was to evaluate the effect of applying alum (aluminum sulfate) and aluminum chloride on pH and pathogen populations of Hanwoo manure. A total of 36 steers (8 months old and averaging 300 kg in weight) were used in this trial and allotted to 9 pens (3 replication pens per group with 4 steers per experimental unit, $5{\times}8$ m). Chemical additives were applied as a top dressing with garden rake to a depth of 1 cm of manure with wood shavings in each treatment. The chemical amendments were control (without chemical amendments), 50 g of alum and 50 g of aluminum chloride/kg of Hanwoo manure. The experiment was carried out for 4 weeks. Adding alum and aluminum chloride to Hanwoo manure reduced (P < 0.05) pH compared to untreated controls during the 4-wk period. Both levels of the alum and aluminum chloride treatments tested decreased (P < 0.05) Escherichia coli and Salmonella enterica populations in Hanwoo manure at 2 and 4 weeks. It appears that the reduction in pathogen populations was primarily associated with the lower manure pH. If more strict environmental regulations are put into effect regarding pathogen populations from Hanwoo facilities, treating Hanwoo manure with alum and aluminum chloride may be a good management practice.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.513-516
• /
• 2008

In this study the prediction model of Chloride Ion progress rate of concrete using steel powder as an addition is developed, in which the reduction of not only the diffusion rate of $Cl^-$ but also the corrosion rate by replenishment of pore by corrosion products. The model is based on the diffusions of $Cl^-$ and its reaction with $Fe^{2+}$, in chloride attack progression region. The model can also explain the characteristics of chloride ion permeation resistance of concrete that the matrix is densified due to corrosion products. The prediction by the model agreed well the experimental data in which the concrete using steel powder, and it showed the lower rate in long-term age to Chloride Ion progress rate than the concrete without steel powder. Consequently the model can predict Chloride Ion progress rate of concrete exposed in the atmosphere regardless of the water-to-cement raito, the amount of the content of steel powder, etc.

• Journal of the Korea Concrete Institute
• /
• v.14 no.1
• /
• pp.100-109
• /
• 2002

Significant damage to concrete results from the intrusion of corrosive solutions, for example, dissolved chlorides corrode reinforcing steel and cause spatting. Effectively blocks the penetration of these solutions will eliminate or greatly reduce this damage and lead to increased durability. This study is to investigate the effects of pozzolanic admixtures, fly ash and silica fume, and a blast furnace slag on the chloride ion penetration of concretes. The main experimental variables wore the water-cementitious material ratios, the types and amount of admixtures, and the curing time. And it is tested for the porosity and pore size distributions of cement paste, chloride ion permeability based on electrical conductance, and 180-day ponding test for chloride intrusion. The results show that the resistance of concrete to the penetration of chloride ions increases as the w/c was decreased, and the increasing of curing time. Also, concrete with pozzolans exhibited higher resistance to chloride ion penetration than the plain concrete. The significant reduction in chloride ion permeability(charge passed) of concrete with pozzolans due to formation of a discontinuous macro-pore system which inhibits flow. It is shown that there is a relationship between chloride ion permeability and depth of chloride ion penetration of concrete, based on the pore structure (porosity and pore size distributions) of cement paste.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.8
• /
• pp.1449-1450
• /
• 2008

• Bulletin of the Korean Chemical Society
• /
• v.9 no.1
• /
• pp.62-64
• /
• 1988

• Korean Journal of Agricultural Science
• /
• v.5 no.2
• /
• pp.80-86
• /
• 1978

This study was carried out in order to know the effect of T. T. C. reaction on antibiotics, cleanser, disinfectants, pH, acidity and station of culture a bacterial Streptococcus thermophilus was used to 2.3.5-triphenyl tetrazolium chloride reduction test for the detection of residual antibiotics in milk were tested. The results obtained were summarized as follows. 1. The T. T. C. reaction was most sensitive in the group of penicillin as 0.02~0.05 IU and also it was less sensitive in Streptomycin and various broad antibiotics except Vibramycin, Synthomycin and Teramycin but it was least sensitive in Streptomycin group. 2. For ther T. T. C. reaction test on cleanser, the positive reaction was appeared above 0.7% of Hi-Ti and 0.1% of NaOH solution respectively. 3. For the T. T. C. test reaction on disinfectants, the positive reaction was occured on 200~500 ppm solution of sodium-hypochlorite and chloride-lime, 0.15~0.35% solution of phenol, cresol and Iode-K. 4. The optimum temperature was $35{\sim}37^{\circ}C$ and proper culturing time was 12 to 18 hours for propagation culturing. 5. The suspect positive reaction was tested above pH 5.0 and the positive reaction was appeared above 0.21% of acidity.

• Journal of Food Hygiene and Safety
• /
• v.22 no.2
• /
• pp.132-136
• /
• 2007

Disinfectants/sanitizers, showing the bactericidal activity of $5log_{10}$ reduction against E. coli ATCC 10536 and Staphylococcus aureus ATCC 6538 used far assessing disinfectants/sanitizers efficacies, were examined whether showing similar efficacies against Salmonella spp. and Listeria monocytogenes, the major food poisoning bacteria, isolated from foods in current Korean market. The bactericidal efficacies on sodium hypochlorite and benzalkonium chloride were assessed by quantitative suspension tests in both 'clean' and 'dirty' conditions, respectively. Test organisms were consisted of E. coli ATCC 10536, Staphylococcus aureus ATCC 6538, Salmonella typhimurium ATCC 13311, Salmonella Enteritidis ATCC 13076, Listeria monocytogenes ATCC 19111, 10 kinds of Salmonella spp. from foods, and 11 kinds of Listeria monocytogenes from foods. More than $5log_{10}$ reduction in viable count for all strains was only achieved with benzalkonium chloride at the tolerance exemption concentration under dirty conditions. However, all strains were achieved more than $5log_{10}$ reduction under clean conditions.

• Korean Journal of Environmental Agriculture
• /
• v.34 no.1
• /
• pp.30-37
• /
• 2015

BACKGROUND: During the winter, the use of deicers was rapidly increased for reduction of traffic accidents as well as injuries in Korea, whose components are largely comprised of calcium chloride and sodium chloride. Recently, to reduce the adverse effects of chloride-deciers such as pollution of water and soil, and decrease of agricultural productivity, the attention of eco-friendly deciers have been increased. This study aimed to investigate biological effects of magnesium chloride deicer (PC-10) and organic acid deicer (EFD-1) against wheat, barley, and spinach. METHODS AND RESULTS: We examined the effect of two deciers, PC-10 and EFD-1 on the seed germination and growth of wheat, barley and spinach. EFD-1 showed higher suppression of the germination than PC-10 among tested crop seeds. In demage index of the seedlings of the crops, there was no symptoms in spinach such as spotting and color change of leaves. EFD-1 showed much stronger inhibitory effect on the germination of tested crop seeds than PC-10 when crops were exposed continuously to tested deciers in soils. The growth and shoot and root in examined crops was relatively higher in PC-10 treatment than in EFD-1 treatment when compared to the control. The biomass decrease was found in all examined conditions of deciers. PC-10 showed 23-35% reduction of biomass whereas EFD-1 exhibited 39-84% loss in all examined crops at over 2% concentration. CONCLUSION: These results suggest that the effects of deicers used in this study by inputting into soil against growing tested crops cause the reduction of germination of seeds, growth, and biomass compared to the control.

• Journal of Powder Materials
• /
• v.19 no.5
• /
• pp.356-361
• /
• 2012

The ultra-fine and less agglomerated titanium carbonitride particles were successfully synthesized by magnesiothermic reduction with low feeding rate of $TiCl_4+1/4C_2Cl_4$ solution. The sub-stoichiometric titanium carbide ($TiC_{0.5{\sim}0.6}$) particles were produced by reduction of chlorine component by liquid magnesium at $800^{\circ}C$ of gaseous $TiCl_4+1/4C_2Cl_4$ and the heat treatments in vacuum were performed for 5 hours to remove the residual magnesium and magnesium chloride mixed with produced $TiC_{{\sim}0.5}$. The final $TiC_{{\sim}0.5}N_{0{\sim}0.5}$ particle with near 100 nm in mean size and high specific surface area of $65m^2/g$ was obtained by nitrification under nitrogen gas at $1,150^{\circ}C$ for 2 hrs.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.168-171
• /
• 2003

This research was conducted to assess the performance of the mixed reactive materials with sand, iron filings, and HDTMA-bentonite for trichloroethylene (TCE) and chromate removal under controlled groundwater flow conditions. TCE and chromate removal rates with the mixtures of iron filing/HDTMA-bentonite were highest among four columns due to reduction by iron filings and sorption by HDTMA-bentonite. The greater capacity of the mixed iron filing/HDTMA-bentonite compared HDTMA-bentonite was due to an enhanced chromate reduction in addition to chromate sorption. The presence of chromate caused greater inhibition of TCE removal in the column with iron filings, while the presence of TCE caused less inhibition of TCE. Also, nitrate caused the decrease in TCE removal relative to chloride. Nitrate ions may also significantly affect TCE reduction rates by competing for electrons with the chlorinated compounds. The anion and co-existed contaminants competing effects should be considered when designed permeable reactive barriers (PRBs) composed of zero valent iron for field applications to remediate TCE and chromate.