• Journal of People, Plants, and Environment
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• v.21 no.6
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• pp.445-460
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• 2018

Exposure to indoor air pollution is an emerging world-wide problem, with growing evidence that it is a major cause of morbidity worldwide. Whilst most indoor air pollutants are of outdoor origin, these combine with a range of indoor sourced pollutants that may lead to high pollutant levels indoors. The pollutants of greatest concern are volatile organic compounds (VOCs) and particulate matter (PM), both of which are associated with a range of serious health problems. Whilst current buildings usually use ventilation with outdoor air to remove these pollutants, botanical systems are gaining recognition as an effective alternative. Whilst many years research has shown that traditional potted plants and their substrates are capable of removing VOCs effectively, they are inefficient at removing PM, and are limited in their pollutant removal rates by the need for pollutants to diffuse to the active pollutant removal components of these systems. Active botanical biofiltration, using green wall systems combined with mechanical fans to increase pollutant exposure to the plants and substrate, show greatly increased rates of pollutant removal for both VOCs, PM and also carbon dioxide ($CO_2$). A developing body of research indicates that these systems can outperform existing technologies for indoor air pollutant removal, although further research is required before their use will become widespread. Whilst it is known that plant species selection and substrate characteristics can affect the performance of active botanical systems, optimal characteristics are yet to be identified. Once this research has been completed, it is proposed that active botanical biofiltration will provide a cheap and low energy use alternative to mechanical ventilations systems for the maintenance of indoor environmental quality.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.4
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• pp.5-10
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• 2018

In this study, the effect of physico-chemical factors (e.g., pressure, electrolyte, and organic matter) in the gas hydrate deposit on CH4-CO2 replacement process was investigated experimentally. The higher initial pressure during gas injection led the higher reaction rate at the first time, but finally it did not. Electrolytes and organic matter have some effects on reforming process after dissociation of gas hydrate. It is expected that further research using real marine sediments with actual gas hydrate will enable the development of technologies applicable to the characteristics of domestic seabed geology. Ultimately, it is expected that it will be possible to recover and utilize methane as an organic resource through application of domestic gas hydrate deposit in the Ulleung Basin, East Sea.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.287-293
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• 2022

The hydroxylation of methane (CH₄) is crucial to the field of environmental microbiology, owing to the heat capacity of methane, which is much higher than that of carbon dioxide (CO₂). Soluble methane monooxygenase (sMMO), a member of the bacterial multicomponent monooxygenase (BMM) superfamily, is essential for the hydroxylation of specific substrates, including hydroxylase (MMOH), regulatory component (MMOB), and reductase (MMOR). The diiron active site positioned in the MMOH α-subunit is reduced through the interaction of MMOR in the catalytic cycle. The electron transfer pathway, however, is not yet fully understood due to the absence of complex structures with reductases. A type II methanotroph, Methylosinus sporium 5, successfully expressed sMMO and hydroxylase, which were purified for the study of the mechanisms. Studies on the MMOH-MMOB interaction have demonstrated that Tyr76 and Trp78 induce hydrophobic interactions through π-π stacking. Structural analysis and sequencing of the ferredoxin domain in MMOR (MMOR-Fd) suggested that Tyr93 and Tyr95 could be key residues for electron transfer. Mutational studies of these residues have shown that the concentrations of flavin adenine dinucleotide (FAD) and iron ions are changed. The measurements of dissociation constants (K_ds) between hydroxylase and mutated reductases confirmed that the binding affinities were not significantly changed, although the specific enzyme activities were significantly reduced by MMOR-Y93A. This result shows that Tyr93 could be a crucial residue for the electron transfer route at the interface between hydroxylase and reductase.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.6
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• pp.439-446
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• 2022

Efforts to reduce carbon dioxide(CO₂) emissions are being carried out due to climate environmental problems. Eco-friendly ships are also being developed, and various energy saving measures have been developed and applied. In ships, researches have been conducted in various fields such as electric propulsion system and energy saving devices. In addition, the development of ships using various renewable energy, such as kite using wind power and wind power generation, has been carried out. This paper proposes a plan to use renewable energy for ships by applying wave generators to small ships. In 2016, 130 small domestic ships drifted by sea due to discharge of starting storage batteries, and discharge cases accounted for the largest portion of the causes of domestic ship accidents. This is due to the excessive use of storage batteries for starting the main engine by departing in a weak storage battery state for small ships. Accordingly, two type wave power generators - opened flow wave power generator and enclosed vibrator type wave power generator - are developed for charging a starting storage battery when the ships are stationary at sea or port. Opened flow wave power generator utilizes the flow of fluid in the ship by using wave induced ship motion. Enclosed vibrator type wave power generator utilizes the pendulum kinetic energy located in a ship due to wave induced ship motion.

• Advances in concrete construction
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• v.13 no.4
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• pp.315-325
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• 2022

Reinforced concrete structures are exposed throughout their lifetime to the phenomenon of carbonation, which considerably influences their durability by causing corrosion of the reinforcements. The fight against this phenomenon is usually ensured by anti-carbonation coatings which have the possibility of limiting the permeability to carbon dioxide or with coatings which absorb the CO₂ present in the air. A coating with good crack-bridging (sealing) capacity will prevent water from entering through existing cracks in concrete. Despite the beneficial effect of these coatings, their durability decreases considerably over time with temperature and humidity. In order to use coatings made from local materials, not presenting any danger, available in abundance in our country, very economical and easy to operate is the main objective of this work. This paper aim is to contribute to the formulation of a corrected dune sand-based mortar as an anti-carbonation coating for concrete. The results obtained show that the cement mortar based on dune sand formulated has a very satisfactory compressive strength, a very low water porosity compared to ordinary cement mortar and that this mortar allows an improvement in the protection of the concrete against the carbonation of 60% compared to ordinary cement mortar based on alluvial sand. Moreover, the formulated cement mortars based on dune sand have good adhesion to the concrete support, their adhesion strengths are greater than 1.5MPa recommended by the standards.

• Advances in concrete construction
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• v.16 no.1
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• pp.35-57
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• 2023

Majority of the plastic produced each year is being disposed in land after single-use, which becomes waste and takes up a lot of storage space. Therefore, there is an urgent need to find alternative solutions instead of disposal. Recycling and reusing the PET plastic waste as aggregate replacement and fiber in concrete production can be one of the eco- friendly methods as there is a great demand for concrete around the world, especially in developing countries by raising human awareness of the environment, the economy, and Carbon dioxide (CO2) emissions. Self-compacting concrete (SCC) is a key development in concrete technology that offers a number of attractive features over traditional concrete applications. Recently, in order to improve its durability and prevent such plastics from directly contacting the environment, various kinds of plastics have been added. This review article summarizes the latest evident on the performance of SCC containing recycled PET as eco-friendly aggregates and fiber. Moreover, it highlights the influence of substitution content, shape, length, and size on the fresh and properties of SCC incorporating PET plastic. Based on the findings of the articles that were reviewed for this study, it is observed that SCC made of PET plastic (PETSCC) can be employed in construction era owing to its acceptable mechanical and fresh properties. On the other hand, it is concluded that owing to the lightweight nature of plastic aggregate, Reusing PET waste in the construction application is an effective approach to reduces the earthquake risk of a building.

• Journal of Dental Anesthesia and Pain Medicine
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• v.24 no.1
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• pp.67-73
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• 2024

Background: Nitrous oxide has been an integral part of surgical anesthesia for many years in the developed world and is still used in developing countries such as India. The other main concerns in low-resource countries are the lack of an advanced anesthesia gas-scavenging system and modular surgical theatres. As a greenhouse gas that has been present in the atmosphere for more than 100 years and damages the ozone layer, nitrous oxide is three times worse than sevoflurane. Here, we conducted an observational study to quantify the annual nitrous oxide consumption and its environmental impact in terms of carbon dioxide equivalence in one of busiest tertiary health care and research centers in Northern India. Methods: Data related to nitrous oxide expenditure' from the operation theatre and manifold complex of our tertiary care hospital and research center from 2018 to 2021 were collected monthly and analyzed. The outcomes were extracted from our observational study, which was approved by our institutional ethics board (INT/IEC/2017/1372 Dated 25.11.2017) and registered prospectively under the Central Registry (CTRI/2018/07/014745 Dated 05.07.2018). Results: The annual nitrous oxide consumption in our tertiary care hospital was 22,081.00, 22,904.00, 17,456.00, and 18,392.00 m³ (cubic meters) in 2018, 2019, 2020, and 2021, respectively. This indicates that the environmental impact of nitrous oxide (in terms of CO₂ equivalents) from our hospital in 2018, 2019, 2020, and 2021 was 13,016.64, 13,287.82, 10,289.94, and 10,841.24 tons, respectively. Conclusion: This huge amount of nitrous oxide splurge is no longer a matter of laughter, and serious efforts should be made at every central and peripheral health center level to reduce it.

• Journal of environmental and Sanitary engineering
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• v.18 no.1
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• pp.51-57
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• 2003

Indoor air quality(IAQ) in workplace and residential environments has been concern of people. Recently, Ministry of Environment in Korea has recognized the potential risk on the healthy effect related to indoor air pollution at home. Therefore, the purpose of this study was performed to measure the indoor air pollutants of IAQ at different homes and investigate to compare the perception of IAQ recognition at home from questionnaire survey in Seoul. We estimated the IAQ of selected 6 homes based on site region and housing type. The indoor air pollutants and parameters such as temperature, relative humidity, respirable suspended particulate matter($PM_{10}$), formaldehyde(HCHO), total bacteria counts, carbon monooxide(CO) and carbon dioxide($CO_2$) were monitored for summer and winter. In monitoring results, the respirable suspended particulate matter(($PM_{10}$) and indoor airborne bacteria level of home 5 and 6 were higher than the standard of the public $150{\;}{\mu}g/m^3$ and $500{\;}{\mu}g/m^3$, the level formaldehyde(HCHO) was exceed 0.1 ppm of the standard of Korea at all monitored homes. In statistics analysis, we could find a correlation between the building age and the concentration of CO, TBC were significant at 0.01 level and Relative Humidity was significant at 0.05 level for summer. Finally, the important air pollutants of IAQ in home were HCHO and total bacteria counts(TBC). And we performed a questionnaire survey of 500 people about their awareness for the importance of IAQ in our home during same period. In results, all most response of occupant has recognized the importance of IAQ at home. Therefore, it can be concluded that the IAQ of selected 6 home studied was perceived as acceptable, it is recommended that the government related IAQ was suggested the guideline and control of IAQ problems, and the occupants need to be effort to reduce the exposure of sources to undesirable pollutants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.386-391
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• 2021

Turbocharging is becoming a key technology for both diesel and gasoline engines. Regarding gasoline engines, turbocharging can help reduce carbon dioxide (CO2) emissions when used in conjunction with other technologies. This paper presents measurements of the turbine efficiency of pulsating flow in a twin-scroll turbocharger for gasoline engines. A cold gas test bench with a pulse generator was manufactured. The turbine efficiencies were calculated using the measured data of the instantaneous pressure and temperature of the inlet and exit of the turbine. The measurements were carried out at turbine speeds from 60,000 to 100,000 rpm under a pulsating flow of 25.0 Hz and 33.0 Hz. The turbine efficiencies ranged from 0.517 to 0.544. At the pulse frequency, 33.3 Hz, the variations in efficiency were 7.7% and 2.6% at turbine speeds of 60,000 rpm and 100,000 rpm, respectively. The turbine efficiency of the pulsating flow compared to those of steady flow was 7.0% and 3.0% lower at a turbine speed of 60,000 rpm and 100,000 rpm, respectively. The pulsating flow deteriorated the turbine efficiency, but the effects of pulsating flow decreased with increasing turbine speed.

• Korean Journal of Organic Agriculture
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• v.29 no.3
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• pp.415-427
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• 2021

It is generally recognized that high stocking density can increase the risk of immune dysfunction and reduction in productivity cause of elevated stress in broiler farm. The domestic livestock industry is implementing a certification system for animal welfare and livestock farms to reduce the problem of dense breeding. This study compared broiler from the general farm and animal welfare farm to confirm the effectiveness of animal welfare farms against stress. Gas concentrations in a farm of general and animal welfare farms were analyzed, blood (n=10) of the 28-day-old broiler was collected, the partial pressure of the gas in the blood was analyzed using whole blood, and biochemical factors and hormones were analyzed using the serum. Glycogen and L-lactate are analyzed using ELISA kit on finely pulverized muscles (n=10). CO₂ and NH₃ levels in the farm were significantly higher in general farm. Partial carbon dioxide tension (PCO₂) in blood was significantly higher and partial oxygen tension (PO₂) was significantly lower in the general farm. Creatinine (CREA), glucose (GLU), aspartateaminotransferase (AST), and creatinekinase (CK) in the blood were significantly higher in the general farm, and total protein (TP) and globulin (GLOB) were significantly higher in animal welfare farm. Blood corticosterone and norepinephrine were significantly higher in general farm and epinephrine was significantly higher in animal welfare farm. These results imply that animal welfare farm provides a stress-reduced breeding environment.