• International Journal of Safety
• /
• 제4권2호
• /
• pp.24-29
• /
• 2005

An experimental study was presented for extinguishing characteristics of liquid fuel fire by water mist($Dv_{0.99}{\leq}200{\mu}m$) containing potassium acetate and sodium acetate trihydrate. To evaluate the extinguishing performance of water mist containing additives, the evaporation characteristics of a water droplet on a heated surface was examined. The evaporation process was recorded by a charge-coupled-device camera. Also, small-scale extinguishing tests were conducted for n-heptane pool fire in ventilated space. During the experiments, flame temperatures were measured, and concentrations of oxygen and carbon monoxide were analyzed by a combustion gas analyzer. The average evaporation rate of water droplet containing additives was lower than that of pure water at a given surface temperature and decreased with the concentration increase due to the precipitation of salt in the liquid-film and change of surface tension. In case of using additives, the fire extinguishing times was shorter than that of pure water at a given discharge pressure and it was because the momentum of a water droplet containing additives was increased. And also dissociated metal atoms, potassium or sodium, were reacted as a scavenger of the major radical species OH, H which were generated for combustion process. Moreover, at a high pressure of 4 MPa, the fire was extinguished through blowing effect as well as primary extinguishing mechanisms.

• Environmental Engineering Research
• /
• 제20권4호
• /
• pp.342-346
• /
• 2015

Haloacetonitriles (HANs) are nitrogenous disinfection by-products (DBPs) that have been reported to have a higher toxicity than the other groups of DBPs. The adsorption process is mostly used to remove HANs in aqueous solutions. Functionalized composite materials tend to be effective adsorbents due to their hydrophobicity and specific adsorptive mechanism. In this study, the removal of dichloroacetonitrile (DCAN) from tap water by adsorption on thiol-functionalized mesoporous composites made from natural rubber (NR) and hexagonal mesoporous silica (HMS-SH) was investigated. Fourier-transform infrared spectroscopy (FTIR) results revealed that the thiol group of NR/HMS was covered with NR molecules. X-ray diffraction (XRD) analysis indicated an expansion of the hexagonal unit cell. Adsorption kinetic and isotherm models were used to determine the adsorption mechanisms and the experiments revealed that NR/HMS-SH had a higher DCAN adsorption capacity than powered activated carbon (PAC). NR/HMS-SH adsorption reached equilibrium after 12 hours and its adsorption kinetics fit well with a pseudo-second-order model. A linear model was found to fit well with the DCAN adsorption isotherm at a low concentration level.

• Journal of Animal Science and Technology
• /
• 제66권2호
• /
• pp.237-250
• /
• 2024

The emission of noxious gases is a significant problem in pig production, as it can lead to poor production, welfare concerns, and environmental pollution. The noxious gases are the gasses emitted from the pig manure that contribute to air pollution. The increased concentration of various harmful gasses can pose health risks to both animals and humans. The major gases produced in the pig farm include methane, hydrogen sulfide, carbon dioxide, ammonia, sulfur dioxide and volatile fatty acids, which are mainly derived from the fermentation of undigested or poorly digested nutrients. Nowadays research has focused on more holistic approaches to obtain a healthy farm environment that helps animal production. The use of probiotics, prebiotics, dietary enzymes, and medicinal plants in animal diets has been explored as a means of reducing harmful gas emissions. This review paper focuses on the harmful gas emissions from pig farm, the mechanisms of gas production, and strategies for reducing these emissions. Additionally, various methods for reducing gas in pigs, including probiotic interventions; prebiotic interventions, dietary enzymes supplementation, and use of medicinal plants and organic acids are discussed. Overall, this paper provides a comprehensive review of the current state of knowledge on reducing noxious gas in pigs and offers valuable insights for pig producers, nutritionists, and researchers working in this area.

• 한국토양비료학회지
• /
• 제41권1호
• /
• pp.55-64
• /
• 2008

일반적으로 근권부로 알려진, 토양과 뿌리 사이의 계면(soil-root interface)에서 일어나는 주요 기작에 대한 세부적 이해는 성공적인 phytoremediation 기술을 위해 특정 식물의 적용 가능성을 평가하는데 있어 매우 중요하다. 가령 어떤 식물은 토양중 낮은 중금속 유효도라는 제한인자를 극복하기 위해 근권부에서 특정 기작을 일으키기도 한다. 본 연구는 토양 고정 (land stabilization)에 탁월한 효과를 보이고 있는 vetiver grass(Vetiveria zizanioides)를 중금속으로 오염된 3가지의 다른 토양에 재배함으로써, 식물 뿌리가 근권부 토양의 화학적 특성에 미치는 영향과 이에 따른 식물의 중금속 흡수 특성을 조사하였다. Vetiver grass 재배 후 근권부 토양의 토양수 pH는 시험에 이용된 모든 토양에서 0.3-1.1 만큼 증가하였고, 토양수 중 유기탄소의 함량도 $23mg\;L^{-1}$ 에서 $173mg\;L^{-1}$로 가장 많이 증가한 PP02 토양을 비롯해서 모든 토양에서 증가하였다. 이와 같은 근권부 토양수의 화학적 변화는 중금속 오염토양에 노출된 vetiver grass의 뿌리에서 나온 분비물(exudates)에서 비롯된 것이다. 결과적으로 근권부 토양수의 화학적 특성 변화는 중금속(카드뮴, 납, 구리, 아연) 유효도 및 화학종 변화에 영향을 미쳤다. 중금속의 최초 유효도는 시험에 이용된 토양의 종류에 따라 달랐으며 vetiver grass 재배 후 이 유효도의 변화 또한 토양 종류의 영향을 받아 증가 또는 감소하였다. 가장 높은 중금속 유효도를 보인 토양은 Ko01 토양으로 토양수 중 카드뮴과 납의 농도가 각각 $2,091{\mu}g\;L^{-1}$, $318{\mu}g\;L^{-1}$ 이었다. 일반적으로 vetiver grass에 의해 증가한 pH는 중금속 유효도를 감소시켰고, 반면에 증가한 유기탄소는 토양중 중금속과 복합물질을 형성하면서 토양수 중 중금속의 농도를 높였다. Donnan speciation 기술을 이용한 화학종 분리 결과 토양수 중 순이온으로 존재하는 카드뮴과 아연의 농도가 현저히 감소하였고, vetiver grass에 의하여 체내에 축적된 중금속의 함량은 토양중 중금속 총함량이 아닌 토양수 중 중금속 유효도와 깊은 관계를 보였다.

• 한국의류학회지
• /
• 제5권1호
• /
• pp.15-21
• /
• 1981

The effect of fatty acid content in oily soil and conditions of washing on the removal of triglyceride have been studied. Cotton lawn was soiled with the four-component soil-tripalmitin, palmitic acid, dodecyl alcohol and dodecane-and washed in constant temperature waterbath shaker. The detergency was estimated by analysis of triglyceride labelled carbon-14 on fabrics before and after washing by means of liquid scintillation counting. It was shown that the detergency of triglyceride washed with the nonionic, nonylphenol poly (10)-ethylene oxide and soap was increased steadily with increasing temperature, whereas with the anionics Na-DBS and SLS, the detergency was rather decreased when the temperature was elevated above $40^{\circ}C$. To investigate the effects of free fatty acid content in soil on the removal of triglyceride, the fabrics were soiled altering palmitic acid content, and then washed. From the results, the detergency of triglyceride was developed with increasing free fatty acid content. With soils containing less than $30\%$ of free fatty acid, of the three detergents tested, the nonionic was by far the most effective soil removal. Soap was intermediate and the synthetic anionic was the poorest. With soil containing $45\%$ of free fatty acid, soap was the most effective soil removal. When NaOH was added to detergent solution. the detergency of triglyceride was improved without regard to detergents. The optimum alkalinity was obtained according to free fatty acid content. And the alkalinity changed to low NaOH concentration with increasing free fatty acid content. From the results mentioned above, it could be concluded that the major removal mechanisms of triglyceride containing oily soil were mesomorphic phase formation, solubilization and soap forma-tion when alkali was added in detergent solution.

• Journal of Microbiology and Biotechnology
• /
• 제15권3호
• /
• pp.551-559
• /
• 2005

The recent rapid increase in genomic data related to many microorganisms and the development of computational tools to accurately analyze large amounts of data have enabled us to design several kinds of simulation approaches for the complex behaviors of cells. Among these approaches, dFBA (dynamic flux balance analysis), which utilizes FBA, differential equations, and regulatory events, has correctly predicted cellular behaviors under given environmental conditions. However, until now, dFBA has centered on substrate concentration, cell growth, and gene on/off, but a detailed hierarchical structure of a regulatory network has not been taken into account. The use of Boolean rules for regulatory events in dFBA has limited the representation of interactions between specific regulatory proteins and genes and the whole transcriptional regulation mechanism with environmental change. In this paper, we adopted the operon as the basic structure, constructed a hierarchical structure for a regulatory network with defined fundamental symbols, and introduced a weight between symbols in order to solve the above problems. Finally, the total control mechanism of regulatory elements (operons, genes, effectors, etc.) with time was simulated through the linkage of dFBA with regulatory network modeling. The lac operon, trp operon, and tna operon in the central metabolic network of E. coli were chosen as the basic models for control patterns. The suggested modeling method in this study can be adopted as a basic framework to describe other transcriptional regulations, and provide biologists and engineers with useful information on transcriptional regulation mechanisms under extracellular environmental change.

• ALGAE
• /
• 제38권4호
• /
• pp.283-294
• /
• 2023

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation-brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

• 한국산림과학회지
• /
• 제113권1호
• /
• pp.97-106
• /
• 2024

낙엽·낙지에 의한 탄소 및 질소 유입의 정량화는 산림생태계 양분순환 기작의 이해나 산림생산력 증진을 위한 토양양분관리에 중요하다. 본 연구는 서로 인접한 지역에 식재된 동일 영급의 삼나무와 편백 조림지를 대상으로 낙엽트랩을 설치한 후 2020년 12월부터 2021년 12월까지 낙엽·낙지에 의한 탄소 및 질소유입량을 3개월 단위로 조사하였다. 낙엽·낙지량은 꽃, 구과, 종자 같은 생식기관을 제외하고 수종 간 차이가 없었으며, 계절별로는 12월에서 3월에 유입량이 가장 많았다. 낙엽·낙지 중 편백 잎(낙엽)과 종자의 탄소농도는 삼나무에 비해 유의적으로 높았으며 낙엽과 꽃의 탄소농도는 계절별 변동을 보였다. 한편 낙엽의 질소농도도 계절별 변동을 보여 하절기(6월~9월)의 질소농도(삼나무 0.96%, 편백 1.01%)는 타 계절(삼나무 0.43%, 편백 0.53%)에 비해 유의하게 높았다. 수종별 질소농도는 삼나무 구과가 편백에 비해 높은 값을 보였다. 낙엽·낙지 중 낙엽에 의한 탄소 및 질소유입량은 두 수종 모두 12월~3월에 가장 많았으며, 6월~9월은 가장 적게 유입되었다. 연 탄소유입량은 삼나무 조림지 3,054 kg C ha^-1 yr^-1, 편백 조림지 3,129 kg C ha^-1 yr^-1로 두 수종 사이에 차이가 없었다. 연 질소유입량은 삼나무 조림지의 생식기관에 의한 질소유입량이 편백에 비해 크게 나타나 삼나무가 46.93 kg N ha^-1 yr^-1로 편백의 25.17 kg N ha^-1 yr^-1에 비해 약 1.9배 많았다. 본 연구 결과는 삼나무와 편백 조림지에 낙엽·낙지를 포함한 임분 단위 탄소 및 질소순환을 예측하는데 기초자료로 활용될 것으로 기대된다.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.124-124
• /
• 2017

Cadmium (Cd) is of particular concern because of its widespread occurrence and high toxicity and may cause serious morpho-physiological and molecular abnormalities in in plants. The present study was performed to explore Cd-induced morpho-physiological alterations and their potentiality associated mechanisms in Sorghum bicolor leaves at the protein level. Ten-day-old sorghum seedlings were exposed to different concentrations (0, 100, and $150{\mu}M$) of $CdCl_2$, and different morpho-physiological responses were recorded. The effects of Cd exposure on protein expression patterns in S. bicolor were investigated using two-dimensional gel electrophoresis (2-DE) in samples derived from the leaves of both control and Cd-treated seedlings. The observed morphological changes revealed that the plants treated with Cd displayed dramatically altered shoot lengths, fresh weights, and relative water content. In addition, the concentration of Cd was markedly increased by treatment with Cd, and the amount of Cd taken up by the shoots was significantly and directly correlated with the applied level of Cd. Using the 2-DE method, a total of 33 differentially expressed protein spots were analyzed using MALDI-TOF/TOF MS. Of these, treatment with Cd resulted in significant increases in 15 proteins and decreases in 18 proteins. Significant changes were absorbed in the levels of proteins known to be involved in carbohydrate metabolism, transcriptional regulation, translation and stress responses. Proteomic results revealed that Cd stress had an inhibitory effect on carbon fixation, ATP production and the regulation of protein synthesis. In addition, the up-regulation of glutathione S-transferase and cytochrome P450 may play a significant role in Cd-related toxicity and stress responses. Our study provides insights into the integrated molecular mechanisms involved in response to Cd and the effects of Cd on the growth and physiological characteristics of sorghum seedlings. The upregulation of these stress-related genes may be candidates for further research and use in genetic manipulation of sorghum tolerance to Cd stress.

• 한국토양비료학회지
• /
• 제43권2호
• /
• pp.242-251
• /
• 2010

이 논문은 장기간에 걸쳐 논 생태계에서 측정된 이산화탄소와 메탄의 순교환량 과 이와 동시에 모니터링된 다양한 환경요소들과의 상관관계들을 살펴보고, 이들 플럭스와 환경 요소 및 생태계 요소들이 어떻게 교환된 이산화탄소와 메탄의 동위원소비에 영향을 미치는 지를 파악하고자 하였다. 생육기간 동안 관측된 이산화탄소 및 메탄의 순교환량은 는 담수기에는 각각 일사량과 토양온도의 변화에 따라 경시적인 변화를 보였으나, 낙수기를 전후해서는 토양에 저장되어 있던 가스들이 낙수 후 확산장벽이 사라짐으로 인해 급격히 대기 중으로 대량 방출되는 경향을 보였다. 이러한 플럭스의 변화는 토양 중에 저장되어 있는 이산화탄소와 메탄의 저장량 감소와 직접적으로 연결되었고, 이에 상응하는 순교환량 중 토양의 기여분 증가와 대기 중 이산화탄소 및 메탄의 농도 증가 및 동위원소비 변화가 관찰되었다. 이러한 변화는 환원상태에서 진행되는 메탄생성의 결과로, 기질인 이산화탄소는 상대적으로 무거운 $^{13}C$ 동위원소가 축적되는 반면, 생성물인 메탄은 가벼운 $^{12}C$ 동위원소가 축적되기 때문으로 판단된다. 따라서, 토양 유래 이산화탄소는 식물체 호흡 유래 이산화탄소와 구분되는 동위원소 특성을 지내게 된다. Keeling plot 혼합 모델로 추정된 이산화탄소와 메탄의 가스교환 동위원소 지문은 담수기와 낙수기에 걸쳐 매우 뚜렷한 변화를 보였으며, 그 변화 정도는 토양 중 가스 저장량, 교환된 플럭스의 크기 및 방향, 이동 경로, 부분적인 방출 이산화탄소의 재흡수도, 메탄의 산화정도 등에 의해 크게 달랐다. 본 연구의 결과들은 자연상태에서 관측된 플럭스와 결합된동위원소 기술이 생태계 내 다양한 가스 교환 메커니즘을 이해하는데 매우 유용한 도구가 될 수 있음을 보여주였다.