• Title/Summary/Keyword: Environmental Condition

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A Study on the Development of Cooling Simulation Program for Thermal Environmental Chamber (열환경챔버의 냉방 시뮬레이션 프로그램 개발에 관한 연구)

  • 이한홍
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.5
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    • pp.108-114
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    • 1999
  • The thermal environmental chamber has been using in maintaining weather condition keeping thermal capacity under heating and cooling load fluctuation and for the performance testing of cooling system or air-conditioner on artificial envi-ronment. In ordder to make the various environmental conditions in the thermal environmental chamber the proper cooling system is necessary to eliminate the heating load produced inside the chamber and to maintain the designed environmental condition. For this reason the optimal design of cooling system and the prediction of performance is also required. This paper describes the prediction of performance of cooling system in the thermal environmental chamber with the capacity of 37,000kcal/hr which is developed for the test of performance in heating mode of heat pump system, In the results this paper is trying to develop simulation program on the base of mathematical models and which can be applied effectively to the optimal design of cooling system and prediction of performance to the inside and outside change of envi-ronmetal load.

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Trends and Tasks of Methodology in Environmental Education Research of Korea and Other Countries (국내외 환경교육 연구방법론의 동향과 과제)

  • 고운미;김대희
    • Hwankyungkyoyuk
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    • v.14 no.2
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    • pp.142-155
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    • 2001
  • The purpose of this stud)r was to critically review the trends of research methodologies of environmental education. We analyzed Journal of Korean Society for Environmental Education (vol. 1 ∼vol. 14(1)) and The Journal of Environmental Education(vol. 25∼vol. 31) to investigate the trends of methodology in EE research of Korean and other countries and to explore the tasks of it. The findings were as follows, 1) More than half of the character of the papers in Korea were actual condition (54.38%), substitute proposal (32.12%), and the papers in others countries were actual condition (39.35%), substitute proposal (33.55%). 2) The major parts of the method of the papers in Korea were literature review (26.05%), survey research (23.79%), on the other hand the papers in other counties were survey research (42.70%), literature review (25.84%). The results indicated that the research methodologies of environmental education in Korea were needed to be reinforced in the field of qualitative and quantitative research methods.

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Reductive dechlorination of tetrachloroethylene by bimetallic catalysts on hematite in the presence of hydrogen gas

  • Choi, Kyunghoon;Lee, Nara;Lee, Woojin
    • Advances in environmental research
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    • v.3 no.2
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    • pp.151-162
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    • 2014
  • Among the combination of 4 different second metals and 3 different noble metals, Ni 10%-Pd 1%/hematite (Ni(10)-Pd(1)/H) showed best tetrachloroethylene (PCE) removal (75.8%) and production of non-toxic products (39.8%) in closed batch reactors under an anaerobic condition. The effect of environmental factors (pH, contents of Ni and Pd in catalyst, and hydrogen gas concentration) on the reductive dechlorination of PCE by Pd-Ni/hematite catalysts was investigated. PCE was degraded less at the condition of Ni(5)/H (13.7%) than at the same condition with Ni(10)/H (20.6%). Removals of PCE were rarely influenced by the experimental condition of different Pd amounts (Pd(1)/H and Pd(3)/H). Acidic to neutral pH conditions were favorable to the degradation of PCE, compared to the alkaline condition (pH 10). Increasing Ni contents from 1 to 10% increased the PCE removal to 89.8% in 6 hr. However, the removal decreased to 74.2% at Ni content of 20%. Meanwhile, increasing Pd contents to 6% showed no difference in PCE removal at Pd content of more than 1%. Increasing H2 concentration increased the removal of PCE until 4% H2 which was maximumly applied in this study. Chlorinated products such as trichloroethylene, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, and vinyl chloride were not observed while PCE was transformed to acetylene (24%), ethylene (5%), and ethane (11%) by Ni(10)-Pd(1)/H catalyst in 6hr.

Development of sewer condition assessment and rehabilitation decision-making program(SCARD) (하수관거 평가 및 정비 우선순위 의사결정도구 개발)

  • Han, Sangjong;Hwang, Hwankook
    • Journal of Korean Society of Water and Wastewater
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    • v.29 no.1
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    • pp.123-131
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    • 2015
  • A CCTV inspection method has been widely used to assess sewer condition and performance, but Korea lacks a proper decision support system for prioritizing sewer repair and rehabilitation (R&R). The objective of this paper is to introduce the results that we have developed in the Sewer Condition Assessment and Rehabilitation Decision-making (SCARD) Program using MS-EXCEL. The SCARD-Program is based on a standardized defect score for sewer structural and hydraulic assessment. Priorities are ranked based on risk scores, which are calculated by multiplying the sewer severity scores by the environmental impacts. This program is composed of three parts, which are decision-making for sewer condition and performance assessment, decision-making for sewer R&R priority assessment, and decision-making for optimal budget allocation. The SCARD-Program is useful for decision-makers, as it enables them to assess the sewer condition and to prioritize sewer R&R within the limited annual budget. In the future, this program logic will applied to the GIS-based sewer asset management system in local governments.

Growth and gut performance of young pigs in response to different dietary cellulose concentration and rearing condition

  • Cho, Hyun Min;Kim, Eunjoo;Wickramasuriya, Samiru Sudharaka;Shin, Taeg Kyun;Heo, Jung Min
    • Animal Bioscience
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    • v.34 no.10
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    • pp.1653-1662
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    • 2021
  • Objective: This experiment was conducted to investigate the effect of insoluble cellulose supplementation to diets on the growth performance, intestinal morphology, the incidence of diarrhea, nutrients digestibility, and inflammatory responses in altering environmental conditions of animals housing. Methods: A total of 108 male pigs (Duroc×[Yorkshire×Landrace]) were randomly allocated to one of three dietary treatments (cellulose 0%, 1%, 2%) and two environmental conditions (good sanitary condition vs. poor sanitary condition) to give 6 replicate pens per treatment with three pigs per each pen at 14 days post-weaning. Results: Pigs were in good sanitary condition had higher average daily gain (p<0.01) and improved feed efficiency (p<0.05) from day 1 to 14 after weaning compared to their counterparts. The interactions were found between environmental conditions and dietary treatments (day 7: crypt depth [p<0.01], villous height to crypt depth [p<0.001]; day 14: crypt depth [p<0.001], villous to crypt ratio [p<0.01]) in ileum morphology. Crypt depth was decreased (p<0.05), and villous to crypt ratio was increased (p<0.05) only in poor sanitary conditions. Pigs exposed to the good sanitary condition had higher (p<0.05) apparent ileal digestibility (day 7, gross energy; day 14, dry matter), apparent total tract digestibility (day 14, dry matter and crude protein) compared to pigs housed in the poor sanitary condition. Meanwhile, pigs fed a diet supplemented with 2% cellulose had decreased (p<0.05) apparent ileal digestibility (day 7, dry matter; day 14, crude protein), apparent total tract digestibility (day 7, dry matter; day 14, crude protein, gross energy) compared to pigs fed a diet supplemented with 0% or 1% cellulose. Conclusion: Our results indicated that a diet supplemented with 1% cellulose increased villous to crypt ratio, however feeding a diet containing cellulose (1% or 2%) impaired nutrient digestibility for 14 day after weaning in both good sanitary and poor sanitary conditions.

Evaluation of Air Quality Inside Passenger Car with Operating Air Quality System (공기질 조절장치 작동 승용차 내부의 공기질 평가)

  • 조완근;박건호
    • Journal of Environmental Science International
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    • v.7 no.5
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    • pp.573-580
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    • 1998
  • This study examined the carbon dioxide ($CO_2$) pollution inside vehicles under low ventilation condition and evaluated the Air Quality System (AQS) for in-vehicle air quality using two techniques. The low ventilation condition is not recommended in order to keep oxygen-rich condition inside vehicles. Under the low ventilation condition, the in-vehicle $CO_2$ concentrations exceeded 1,000 ppm, the air qualify guidelines in the United States, Western Europe, and Japan, indicating more oxygen deficiency inside vehicles. On the contrary, with the AQS-on condition, the in-vehicle $CO_2$ concentrations were less than 1,000 ppm fer most of the driving time, indicating that the AQS could solve the problem of $CO_2$ accumulation inside vehicles under the low ventilation condition. The AQS test conducted by comparing carbon monoxide (CO) and volatile organic compound (VOC) concentrations inside two vehicles indicated that the AQS effectively decreased the in-vehicle concentrations by 21 to 36%, as compared to medium ventilation condition with the windows closed, the vent opened, and air conditioning on. In addition, The AQS test conducted by comparing the interior and exterior concentrations indicated that the AQS effectively decreased the in-vehicle concentrations by 18 to 31%, as compared to medium ventilation condition.

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Lead Poisoning: Historical Aspects of a Paradigmatic "Occupational and Environmental Disease"

  • Riva, Michele Augusto;Lafranconi, Alessandra;D'orso, Marco Italo;Cesana, Giancarlo
    • Safety and Health at Work
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    • v.3 no.1
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    • pp.11-16
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    • 2012
  • Lead poisoning is one of the earliest identified and most known occupational disease. Its acute effects have been recognized from antiquity when this condition principally afflicted manual workers and slaves, actually scarcely considered by the medicine of that time. The Industrial Revolution caused an epidemic of metal intoxication, urging scientists and physician of that period to study and identify specific symptoms and organ alterations related to chronic lead poisoning. During the 20th century, the acknowledgment of occupational and environmental toxicity of lead fostered public awareness and legislation to protect health. More recently, the identification of sub-clinical effects have greatly modified the concept of lead poisoning and the approaches of medicine towards this condition. Nowadays, lead poisoning is rarely seen in developed countries, but it still represents a major environmental problem in certain areas. Consequently, it may appear as a paradigm of "occupational and environmental disease," and the history of this condition seems to parallel the historical development of modern "Occupational and Environmental Health" as a more complete medical discipline.

SYNTHESIS OF NANO-SIZED IRON FOR REDUCTIVE DECHLORINATION. 1. Comparison of Aerobic vs. Anaeriobic Synthesis and Characterization of Nanoparticles

  • Song, Ho-Cheol;Carraway, Elizabeth R.;Kim, Young-Hun
    • Environmental Engineering Research
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    • v.10 no.4
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    • pp.165-173
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    • 2005
  • Nano-sized iron particles were synthesized by reduction of $Fe^{3+}$ in aqueous solution under two reaction conditions, aerobic and anaerobic, and the reactivity of iron was tested by reaction with trichloroethene (TCE) using a batch system. Results showed that iron produced under anoxic condition for both synthesis and drying steps gave rise to iron with higher reduction reactivity, indicating the presence of oxygen is not favorable for production of nano-sized iron deemed to accomplish reactivity enhancement from particle sized reduction. Nano-sized iron sample obtained from the anoxic synthesis condition was further characterized using various instrumental measurements to identity particle morphology, composition, surface area, and particle size distribution. The scanning electron microscopic (SEM) image showed that synthesized particles were uniform, spherical particles (< 100 nm), and aggregated into various chain structures. The effects of other synthesis conditions such as solution pH, initial $Fe^{3+}$ concentration, and reductant injection rate on the reactivity of nano-sized iron, along with standardization of the synthesis protocol, are presented in the companion paper.

Oxygen Supersaturation in Korean Streams as a Stress Factor to Fish (어류 스트레스 요인으로서 우리나라 하천의 산소과포화 실태)

  • Lee, Saeromi;Lee, JaeYong;Choi, Jaeseok;Kim, Sunjung;Ahn, Buyoung;Kim, Bomchul
    • Journal of Korean Society on Water Environment
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    • v.28 no.2
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    • pp.213-218
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    • 2012
  • Abnormal dissolved oxygen concentration in aquatic habitat, both depletion and supersaturation, can be stress factor to aquatic animals. In this study the nationwide distribution of oxygen supersaturation was analyzed for three categories of streams (43 urban streams, 15 rural streams, and 14 forest streams) by using monitoring network data of the Korean Ministry of Environment. From the distribution analysis 30% of urban streams showed hyperoxic condition of eutrophic level, while no forest stream showed hyperoxic condition. The physiological effect of hyperoxia on fish was examined using two species of fish Zacco koreanus, which resulted in higher concentration of a stress hormone (cortisol) in fish exposed to hyperoxic concentration (196%) of oxygen. This study shows that hyperoxic condition is ubiquitous in urban and rural Korean streams, and it can be a stress factor to aquatic animals.

Electrodialysis with a channeled stack for high strength cadmium removal from wastewater

  • Kyung Jin, Min;Hyo Jin, An;Ah Hyun, Lee;Hyun-Gon, Shin;Ki Young, Park
    • Membrane and Water Treatment
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    • v.14 no.1
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    • pp.47-54
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    • 2023
  • In this study, high concentrations of cadmium-containing wastewater were treated by electrodialysis (ED) with a channel stack. The limiting current density (LCD), cadmium removal efficiency, and current efficiency were investigated under each experimental condition according to the Reynolds number (Re), membrane area, and pH. With the increase in the film area to 111, 333, 555, and 777 cm2 at Re (109.1), LCDs decreased to 408.11, 44.45, 35.32, and 13.64 A/m2, respectively. The highest cadmium removal efficiency (99.6%) and current efficiency were obtained for the membrane area of 111 and 777 cm2, respectively. Under changing Re in the pH range of 1 to 4, Re and LCD were proportional under the same pH condition, and pH and LCD tended to be inversely proportional under the same Re condition. Cadmium removal rate was the best at the pH range 3 - 4. It has been found that ED with channeled stacks can be successfully applied to treat wastewater containing high concentrations of cadmium.