• 급식외식위생학회지
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• 제2권2호
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• pp.97-102
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• 2021

The purpose of this study was to investigate the effect of developing and continuously providing on-line hygiene education programs on the improvement of hygiene conditions in children's cafeterias. As a result of the 2020 sanitation and safety checklist analysis, 6 items (personal hygiene, separate use, clean ventilation, temperature control of refrigerators, country of origin, food distribution) were derived and on-line hygiene education programs for each of 6 items were produced. ① Customized educational materials and self-inspection checklists were provided to 208 children's cafeterias. After that, educational videos were provided through Kakao Talk twice a week for 6 months, and they were made available for viewing at any time through YouTube upload, ③ Kakao Talk Through this, a quiz related to the educational video was conducted to give feedback for interaction with the cook. As a result of analyzing the total hygiene and safety checklist score of all registered facility catering centers by visit order, in 2020 it was 82.8 points/100 points, but in 2021, it was 84.2 points (1st round), 89.3 points (2nd round), 91.4 points (3 points) The score improved significantly (p<0.001) as the on-line hygiene education program continued. As a result, significant (p<0.001) changes were observed in the items of 'Knife, chopping board' and 'Sanitation clothes, sanitary hat, sanitary shoes, apron, and sanitary gloves', confirming a clear improvement effect. Therefore, it is considered that the on-line hygiene education program will play a positive role in showing a lasting effect on improving hygiene management in children's cafeterias.

• 환경위생공학
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• 제1권1호
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• pp.81-96
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• 1986

510 random samples were studied during the months of may through November 1985 at the various industries and conclustions were made as follows; 1. $43.94\%$ of the plants studied operated their plants with semiautomatic control system, and better efficiency were observed at the plants where automatic control systems emplorid and also large industries showed more tendency adopting the automatic plant control system. 2. Overall efficiency of the treatment plants were seen much higher at the first and secand discharge class categories then the lower discharge classes, $80.79\%$ of the plants were see their daily plant operation being controlled by the operator himself. 3. The main causes of the plant stopage and in efficient discharge control were found to be malfunctioning of the plants machineries and equipment or inadequate decision made by the management to save chemicals or electricity. 4. The study showed $60\%$ of the industry treated their wastwater wholly and the rest discharged only with dilution without receiving any further treatment, and this tendency pronounced at the 4th and 5th class discharge category industries. 5. $66.17\%$ of the industry had their storage capacity to accommodate the waste discharge during plants outage while $92.67\%$ of the air pollution discharge industries had no means for the plant outage. 6. $56.77\%$ of the studied industry maintained 24 hour operation of their discharge control systems whill $18.67\%$ of air pollution discharge industries and $10.53\%$ of the waste water discharge industries showed no control effort during the night.

• 환경위생공학
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• 제16권2호
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• pp.79-90
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• 2001

Commercial liquid seeds are used for supplying active microbial flora to organic wastewater treatment plants of high feed-to-microorganism ratio and to maintain optimal microbial condition during unsteady state operation of the biological wastewater treatment plant. In addition to bacterial cells, the liquid weeds contain various additives for special purposes as well as organic substrates for energy supply. The additives give physical stability for the maintenance of microbial decomposition activity and ability to control the overgrowth of seed strains. In this work, the effects of addition of two kinds of typical substrate additives, poly aluminum chloride(PAC) and poly aluminum sulfate(PAS) on the consitutional total cell counts(CFU/ml) of four kinds of reorganization liquid seeds(RLS I, RLS II, RLS III and RLS IV) were studied experimentally. The addition of PAC and PAS gave negative effect on TCC constitution for the four seeds studied.

• 환경위생공학
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• 제10권1호
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• pp.98-105
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• 1995

In the treatment of wastewater or sewage plant sludge with high solid concentration, high rate digestion process in which heating and mixing occur at a time is mainly used, and in the case of wastewater containing solid matter below 1000mg/ℓ the recently developed AF or UASB is developed Recently and commonly utilized. But these processes have weakpoints such as clogging of packing media and need of long period of trial run after microorganism granulation. In this point of view, there are active researches on the ASBR( anaerobic sequence batch reaction ) that is capable of treating of organic matter with reactor that has no packing materials and controlling the inflow time, reaction time sedimentation time and outflow time by time control without loss of microorganisms. The objectives of this study are to evaluate the efficiency of ASBR process according to the reaction time, change of treated water quality and gas output rate in the treatment of wheat plant wastewater.

• 환경위생공학
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• 제14권1호
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• pp.62-69
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• 1999

In this study, the synthesis of PZT powder by bubble column reactor was investigated at various reaction conditions. As a result, the volume % of $NH_3$ gas used as a precipitator had no effect on the synthesis, but the more research is needed to control particle size.As a carrier gas, Ar, $O_2$ and air only increased the stirring effect but had no effect chemically on the synthesis. The calcination temperature of prepared PZT powder was about $500-600^{\circ}C$ and the meanparticle size of synthesized PZT powder was about $0.17{\mu}m$. The grain size of sintered body is about $0.5~3{\mu}m$ and this is similar with the value of commercial products.

• 환경위생공학
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• 제5권2호
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• pp.37-43
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• 1990

The term of stress was used by many scientists, but there were several difinitions about stress, and this term are using in societies frequently. Generally stress is defined as equilibrium, harmony, and adaptation to external stimulations, in 1930 s Hans Selye was the first scientist who used the term of stress and he pointed out the stress mean the function of force in body. When we get stress the stimulation go to the sympathetic-adrenomedulla system and epinephrine and norepinnephrine are secreted from adrenal medulla. Author tried to investigate the change of catecholamine secretion from rat urine which were exposed to 80 dB noise environment. The control rat urine released 0.03 $\pm$ 0.01 ng/ml of epinephrine and 0.18 $\pm$ 0.04 ng/ml, but in noise exposed group the epinephrine was 0.42 $\pm$ 0.07 ng/ml and norepinephrine was 2.16 $\pm$ 0.48 ng/ml.

• 환경위생공학
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• 제18권3호통권49호
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• pp.11-20
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• 2003

There are two ways of reducing air pollution. One is the approach of the pollutant source control and the other one is the traffic demand decreasing approach. This study is focusing on the approach of land use planning and optimal location of urban facilities because those are the basic cause to generate transportation demands. So, the purpose of this study would be to analyze the changes of NOx and CO distribution on environmental air by functional hierarchy of urban roads and to make evaluation model of 'Transportation-Land Use -Air Pollution'. It will contribute to improve the air pollution level at same actual traffic generation according to different location.

• 환경위생공학
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• 제22권3호
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• pp.27-33
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• 2007

M. incognita are plant-parasite nematode that cause severe damage to the crops. P. lilacinus are renowned for inhibitation of development of M. incognita's egg. We make a study for enzymatic examining the cause closely that P. lilacinus suppress development of M. incognita's egg by parasiting. The research result is explained the place below. 1. The egg that is exposed to co-enzymes which are cultured in the broth culture starts to change the membrane of egg from 3days. And in 10days, that membrane completely disappear. These are observed through light microscope. Therefore, we know that M. incongnita are controlled by extracellular lytic enzymes that are produced by P. lilacinus. 2. Through scanning electron microscope, we can find that the egg that is attacked by P. lilacinus loses it's membrane gradually, and that loss of the membrane causes transform, which suppresses the development of egg.

• 환경위생공학
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• 제13권2호
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• pp.40-46
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• 1998

For a biological control on a plant pathogen, Pryicularia Oryzae, and a mosquito, Aedes aegypti, Bacillus thuringiensis strain AF6 which produces parasporal inclusion, delta-endotoxin, was isolated. The B. thuringiensis strain AF6 was produced not only an antifungal substance(AFS) against P. oryzae, but also a mosquitocidal delta-endotoxin. The AFS of the strain AF6 in more stable at pH 4.0 than pH 10.0. At the mode of action, the AFS of the strain AF6 was inhibited hypha growth on potato agar plate(pH 5.0), and degraded cell walls of P. oryzae.

• 환경위생공학
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• 제16권3호
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• pp.14-21
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• 2001

The effects of sodium molybdate(Mo) on phospholipid metabolism in sciatic nerve isolated from lead-intoxicated rat were investigated. Four weeks aged albino rats were divided into four groups : normal control group, lead(10 ppm)-treated group, Mo(1 mg/kg)-treated group, lead and Mo-treated group. As a result of the study, Mo significantly increased the rate of incorporation of $2-[^3H]$myo-inositol into polyphosphinositides in lead-intoxicated rat. Mo also increased the rate of phosphatidylcholine metabolism in normal and lead-intoxicated rats. However, Mo did not affect the metabolism of phosphatidylserine and phosphatidylethanola-mine in normal and lead-intoxicated status. These results suggest that Mo might improve lead-intoxicated status by principally enhancing the metabolism of myo-inositol-related phospholipids and by partly phosphatidylcholine in sciatic nerve.