• Environmental Engineering Research
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• 제21권2호
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• pp.132-139
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• 2016

In early 90s the worldwide awareness about the energy crisis and global warming had been increased and emission reduction (by improving energy efficiency), as well as increasing the capacity of clean and renewable energies, showed themselves as the most important steps towards the sustainable development approach. However, investigations on Iran's environmental situation show huge decline in recent decades and apparently there is no sense of urgency about these issues through the vision of Iranian politicians. In this article the idea of replacing the old gas turbines of Polkalleh natural gas compressor station - as one of the main compressor stations of Iran - with newer and more efficient gas turbines is evaluated, emphatically for reducing greenhouse gases emissions and their environmental costs and decreasing natural gas consumption as well. Clearly such idea is costly, but analyzing its economic impacts, huge declines in annual costs and greenhouse gases emissions can be seen as well. So an investment about $95 million can decrease 40% of Polkalleh compressor station annual costs, 25% of natural consumption and 30% of $CO_2$ and $NO_x$ emissions. Besides the simple payback period of this investment is about 2.5 years from the cut-expenses of annual costs.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.284-289
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• 2003

The narrow band-averaged transmissivity of $CO_2-H_2O$ mixtures is expressed by multiplying the transmissivities of $CO_2$ and $H_2O$. Applying the multiplication property of narrow band transmissivities for gas mixtures of $CO_2-H_2O$, the number of gray gases, required for accurate representation of the absorption characteristics by using the narrow band based WSGGM, is significantly increased. To reduce the computational loads by reducing the number of gray gases, we propose a gray gas regrouping process where the gray gases used for the WSGGM are regrouped into a specified number of groups according to the magnitudes of absorption coefficients. To evaluate the proposed WSGGM for gas mixtures, the radiative transfer problems through three-dimensional gas media are considered. The radiative source terms and the radiative heat fluxes obtained by using the proposed method are fairly well compared to those obtained by using the SNB model. The regrouping technique results in an excellent computational efficiency with minor loss of accuracy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1403-1406
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• 2002

Environmental impact of human activities has become a great concern in most of the countries world-wide, and for years. It has recently focused on potential climate changes due to the increase of green house gases content in the atmosphere. One of these gases is $SF_6$, which is an essential material in electrical applications having excellent dielectric and arc-quenching properties. Though the actual contribution of $SF_6$ to global warming is negligible at present, the control of $SF_6$ emissions seems to be nevertheless imperative. Actually, it is listed in the Kyoto protocol that emissions should not only be duly reported but also the electrical industry which is now the major user of this gas must be able to show that it is possible to use this gas and at the same time preserve the environment. For the development of environmentally-benign electric power equipment and systems, novel gases or gas mixtures are strongly required as the alternatives of $SF_6$ gas. Until now, most research work is focused on the $SF_6/N_2$ mixed gas which is suitable for application in the electrical apparatus with slightly non-uniform fields. Recently, $SF_6/CO_2$ mixed gas also is expected to be promising as a $SF_6$ alternative, especially in highly non-uniform fields and in a gas-impregnated film insulation system. Including these results, the author reviews the research trend or reducing the environmental impact of $SF_6$ gas in this paper.

• 한국건축시공학회지
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• 제8권6호
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• pp.131-137
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• 2008

In recent years, the light-weight aggregate has widely been used to reduce the weight of construction structures, and to achieve the thermal insulation of building structures. The purpose of this study is to evaluate the heat resistance of polymer concrete composites with light-weight aggregate made by binders as resin and cement with polymer dispersion. The light-weight polymer concrete composites are prepared with various conditions such as binder content, filler content, void-filling ratio, light-weight aggregate content and polymer-cement ratio, and tested for heat resistant test, and measured the weight reducing ratio, strengths and exhaustion content of gas such as CO, NO and $SO_2$. From the test results, the weight reducing ratio of light weight polymer concrete using UP binder after heat resistance test increase with an increase in the UP content irrespective of the filler content. The weight reducing ratio of polymer cement concrete is considerably smaller than that of UP concrete. In general, the strengths after heat resistance of polymer concrete composites are reduced about 40 to 65% compared with those before test. The exhausted quantity of CO, NO and $SO_2$ gases in polymer concrete composites is less than EPS(Expanded poly styrene). From the this study, it is confirmed that the many types gases discharge according to binder type of polymer concrete composites, its amount is controlled by selection of the binder type and mix proportions.

• 한국산업보건학회지
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• 제29권4호
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• pp.442-451
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• 2019

Objectives: The aim of this study was to review the reduction methods for ammonia (NH₃) and hydrogen sulfide (H₂S) exposure in livestock. Methods: By reviewing domestic and international research reports from Korea and China, reducing ammonia and hydrogen sulfide in livestock pens was analyzed in terms of ventilation, deodorant, and feed additives. In addition, exposure limits in Korea and China were examined through a comparison between 'TLV-TWA and STEL under the Industrial Safety and Health Act in Korea' and 'Management Standards for Air of Livestock Pens in China'. Results and Discussion: In order to effectively control hazardous gases and odors in livestock pens, the enhancement of natural ventilation or the addition of ventilation fans at the pollution source are being examined. Deodorants are used as adsorbents or masking deodorants. Additives to feed were zeolite powder, FeSO₄·7H₂O, enzymes, and microbial preparations. Use of feed additives was low-cost and had significant effects compared to other methods. Zeolite was the most commonly used in feed additive in Chinese cases and proved to be low-cost and effective for reducing harmful gases. Enzyme preparations were shown to stimulate the growth of livestock, but were expensive. Conclusions: This study reviewed and examined domestic and international research papers in Korea and China for reducing ammonia and hydrogen sulfide concentrations in livestock pens. More diverse research and the development of feed additives are needed.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.97-98
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• 2012

The rotary kiln is one of the most widely used industrial reactors for contacting gases and solids. Kilns are mainly used for drying, calcining and reducing solid materials. In an indirected fired rotary kiln, heat is supplied to the outside of the kiln wall. Heat transfer in indirected fired rotary kilns encompasses all the modes of transport mechanisms, that is, conduction, convection and radiation. This paper deal with the heat transfer characteristics of indirect fired rotary kiln for scale up.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.461-468
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• 2023

Edible coatings are one of the most innovative methods to preserve the quality and increase the shelf life of fresh fruits and vegetables. A successful edible coating should have a barrier against gases, especially oxygen and water vapor, and have good surface characteristics. Today, chitosan coating is widely used due to its properties, such as non-toxic, biodegradable, and biocompatibility. Is. Coating the surface of fruits and vegetables with chitosan increases shelf life due to reducing weight loss and reducing respiration rate and also reduces decay due to its antimicrobial and anti-fungal effect. This work discusses the effect of using chitosan coating containing chamomile extract to increase fresh vegetables'shelf life. In addition to increasing the shelf life of vegetables, this method can be used as a solution for the economic management of human resources. The results of this method confirm the successful synthesis of these nanoparticles, and the results of applying this food coating on vegetables have been successful. They have increased the shelf life of vegetables such as basil and spinach.

• Journal of Advanced Marine Engineering and Technology
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• 제25권3호
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• pp.471-486
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• 2001

The principal trends in the course of emission control legislation are reviewed in this paper. In order to keep such a regulation, moreover, an inquiry ito the concrete technical possibility is conducted through review articles, Also, the composition of exhaust gases emitted from a marine diesel engine are investigated as several samples and the measures that can satisfy the value of regulation are handled with laying stress on the control methods discussed to date. It was concluded that various combined systems can be made to reduce NOx emissions without deteriorating substantially navigation costs since many technologies for reducing NOx emissions are being developed. All heat engines suffer from SOx emissions. There are two methods for reducing SOx emissions: desulfurization from exhaust gas and removal of sulfur composition from fuel oil. However it is necessary to watch the development of these technologies to evaluate which method is more favorable. Heat engines have a big problem in the regulation of environmental pollution from exhaust emissions. In the near future, however, diesel engines may be superior to other heat engines, owing to the high thermal efficiency, although the sales of individual models in dises engines may be prosperous and declining.

• 신재생에너지
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• 제7권4호
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• pp.18-29
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• 2011

Biofuls are considered as an option to reduce greenhouse gases emission, increase energy supply diversity and security of supply, as well as an opportunity for job creation and rural development. First of all, biofuls technologies have been promoted as a means for reducing the carbon intensity of the transport sector. Hence, in the last decade biofuels production has been driven by governmental policies. The key instruments widely adopted to foster production and increase consumption have been mandatory blending targets, tax exemptions and sibsidies. As one of the most powerful instruments, biofuel mandates require fuel producers to produce a pre-defined amount (or share) of biofuels and blend them with petroleum fuel. National biofuels mandates are in place 35 countries and partially in place in 6 countries. In this study, we reviewed status of global biofuels policies to reduce greenhouse gases in the European Union, United States and other countires worldwide. Especially, we discussed representative biofuels mandates policies same as Renewable Fuel Standard (RFS, US), Renewable Transport Fules Obligation (RTFO, UK) in transport sector.

• 한국기계가공학회지
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• 제19권1호
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• pp.29-35
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• 2020

Car inspection systems are regularly carried out by the state to ensure the safety and emission status of cars, thereby improving the safety and quality of life by reducing fine dust and greenhouse gases that are the main culprits of vehicle defects and air pollution. These automobile inspections are largely divided into either regular or comprehensive inspections. This study analyzed the smoke measuring probes used in the lug - down 3 mode. In the previously issued paper "Improvement of Soot Probe Efficiency for Automotive Emission Measurement," an improved smoke measurement probe(B) improved on the problems that arise from the current smoke measurement probe (A). In this study, a technique that can improve the probe's inhalation efficiency over the improved (B) probes was applied to probes (C). Probe (C) involves a structure designed close to the center of the circumference of the exhaust pipe, and the suction efficiency was improved by adding a variable center unit.