• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.2
• /
• pp.215-223
• /
• 2006

The internal corrosion of water distribution systems is the main cause for the problem of the public health threat as well as water leakage in the damaged pipeline, red water, and odor and taste of the tap water. This study was examined the effect of chemicals used for pH and alkalinity control and corrosion inhibitors for producing the optimal corrosion control method. Corrosion study at different pH and alkalinity indicated that these control using alkaline chemicals was effective in corrosion rate, Fe release reduction, but examined to be increased in turbidity and corrosion-by-products(TTHMs) problems. The turbidity was slightly increased, requiring caution in controlling corrosion with $Ca(OH)_2$. At pH 9.0, TTHMs concentration is increased two times corn pared with non-control of pH. Using the pipe which had experienced 28 years of exposure, iron release was decreased with the corrosion inhibitor. Consequently, pH, Alkalinity control method using alkaline chemicals must be complemented by corrosion inhibitor application for efficient corrosion control.

• Korean Journal of Microbiology
• /
• v.28 no.2
• /
• pp.162-168
• /
• 1990

The aims of the present study were to evaluate the effects of culture conditions on the biosynthesis of extra-cellular alkaline protease in Streptomyces sp. The formation of aerial mycelia and spores were compared with the protease production in order to know the relations between the alkaline protease and the cell differentiation. As results, it was found that substrate concentration was very critical to regulate the formation of the protease, aerial mycelia, and spores, which were resulted from the changes of culture pH to acid. When the culture pH was adjusted with phosphate buffer from pH 6 to pH 9, the alkaline protease production was increased as the culture pH increased whereas aerial mycelia and spore formation were reversely related to the culture pH. Therefore, it was thought that the culture pH was an important factor to regulate the alkaline protease synthesis.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.201-204
• /
• 2002

The gellan was extracellular polysaccharide produced by Pseudomonas elodea A TCC 31461 at aerobic condition. Gellan provides various functionalities such as gelling, suspending, stabilizing, emulsifying and binding properties in aqueous systems. In this study, the effect of pH on the cell growth and the gellan production were evaluated in shake- flasks and in 5 ${\ell}$ batch fermentor. In the shake-flasks culture, maximum gellan production was obtained with 1.66g/ ${\ell}$ when initial pH was 7.0. The batch fermentation was performed in the medium pH control ranged pH 5.5-8.5. The maximum gellan production of 1.97g/l was obtained with constant pH 6.0.

• Journal of the Korean Chemical Society
• /
• v.44 no.1
• /
• pp.10-16
• /
• 2000

In general, acid rain is unbuffered solution with low ionic strength and high resistance. Therefore during the pH measurement of acid rain, error can be occurred due to the liquid junction potential difference between the sample and the standard solution. Actually the average conductivity of rain in Taeduk Science Town during 1998 is 12.8 ${\mu}S/cm$, while that of pH standmd solutions is about 5,980 ${\mu}S/cm$. There is a large difference in ionic strength. To compensate the bias due to residual liquid junction potentials, a quality control standard(QCS) of dilute sulfuric acid, which has the conductivity and pH values simikw to rain, was prepared. The pH of QCS solution was determined using the hydrogen electrode system without liquid junction, and compensation has been made for the bias terms by performing the pH measurements with glass electrode. On the basis of this compensation method, the pH vaiues of rain in Taeduk Science Town during 1998 were measured.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.4
• /
• pp.590-598
• /
• 2007

Syrup form medicines which children commonly take contains sugar as sweeteners. Sugar, low endogenous pH, high acidity, mucosity and low concentrations of ions including those of calcium, fluoride, and phosphate in their composition, they can be cause of caries and erosion. Not only the properties found in such medicines, but also other factors such as high frequency of ingestion, bedtime consumption, and the collateral effect of a reduction in salivary flow, poor oral hygiene of sick children may also contribute to the risk. The other side, parents rarely recognize these risk, and medical experts also easily overlook. The purpose of this study was to investigate the pH level of some syrup form medicines which are frequently administered by infants and young children, and their effects on the changes of plaque pH when rinsing with them. And we compared the salivary pH change induced by rinsing with Cough-syrup only and rinsing with Cough-syrup followed by water. The results were as follows : 1. The average pH of syrup form medicines which were prescribed in Pusan National University Hospital and several OTC syrup form medicines was pH $4.7{\pm}0.94$, within the range of pH 3.0 to 6.8. 2. The plaque pH decreased rapidly below pH 5.5 after rinsing with the syrup form medicines which were selected for the test and there was no statistically significant difference in the of plaque pH change between syrup form medicines except COLDI(p>0.05). 3. There was statistically significant difference in salivary pH change between rinsing with Coughsyrup only and rinsing with water after Cough-syrup(p<0.05).

• Journal of Environmental Science International
• /
• v.15 no.4
• /
• pp.379-384
• /
• 2006

Eight USA soils were used for this study. The purpose of this study is to illustrate the characteristics of metals in the soil based on the sequential extraction with increasing pH. Extracts were analyzed for metals by ICP-MS and for dissolved organic carbon(DOC). As the pH increasing, the DOC extracted in each increment initially decreased and reached the minimum at pH 3 and then increased substantially at higher pH values. According to the pH increasing, the extraction of Ca, Cu, and Zn were illustrated as L type. It was found that there were strong correlation between the extracted Fe and DOC($r=0.64{\sim}0.97$).

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.140-144
• /
• 2000

In treatment of contaminated ground by electrokinetic remediation, pH control is the main prolllem for enhancinfi remediation efficiency. In this study, analysed pH variation characteristics according to contaminant(Pb$^{2+}$) concentration and estimated remediation efficiency with organic acid to prevent precipitation in cathode due to hydroxide ion occurrence. Because most of transported Pb$^{2+}$ is precipitatecl according as pH is increased at specimen adjacent to cathode reservoir, little magnitude of Pb$^{2+}$ is flowed out of specimen.cimen.

• Journal of Sasang Constitutional Medicine
• /
• v.1 no.1
• /
• pp.171-181
• /
• 1989

We have studied some effects of the SOYANGIN-HYEONGBANGPAEDOK-SAN (S.H.P.). Several empirical remarks, depending on the different treatments, are investigated through this study as follow; 1. The Analgesic effects of S.H.P. are remarked by Acetic acid method in mice, 100 and 300mg/kg (Sample II, III), 2. The Antipyretic effect of S.H.P. are remarked by yeast method in rats, 100 and 300mg/kg (Sample II, III). 3. The inhibitory effects of S.H.P. on strychnine induced convulsion in mice is remarked. However the inhibitory effects of S.H.P. on picrotoxin induced convulsion in mice is not observed. 4. The effects of S.H.P. on muscle relaxation in mice, using the Rota-Rod test, is remarked on 1,2,3 hours by 300mg/kg (Sample III).

• Journal of Environmental Health Sciences
• /
• v.23 no.1
• /
• pp.74-80
• /
• 1997

This study was performed to estimate the ozonation characteristics of phenol wastewater with increasing pH in the continuous packed column reactor (PCR) and the bubble column reactor (BCR). Among various influencing factors that affect phenol on decomposition through the ozonation, pH was chosen as reaction parameter. Upon increasing pH from 3 to 9, the phenol removal efficiency in PCR was improved approximately by 17% while in BCR approximately by 19.2%. The improvements in the phenol removal efficiency by increasing pH caused the enhancements in ozone utilization efficiency reaching almost 100% in PCR at pH 9. In conclusions, ozone has latent power for phenol wastewater treatment, and the performance of PCR was superior to that of BCR in the aspects of phenol removal and ozone utilization efficiency.

• Journal of environmental and Sanitary engineering
• /
• v.19 no.1
• /
• pp.1-7
• /
• 2004

This study was conducted to supply basic informations on development of water treatment process for the ozonation of ammonia depend on pH variation with or without bromide catalysis. The results were as follows: The oxidation rate of ammonia increased depend on pH increase at ozone/bromide process. It was found that overall kinetics was zero order with respect to reaction time and reaction velocity constant of zero order increased depend on pH increase from 4.9 to 9.5 and the equation of linearization was $k_{o}$ = 0.00565 ${\times}$ [pH] + 0.0069 at ozone/bromide process. The denitrification reaction of ammonia was superior as the pH increase in the presence of bromide.