• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.207-212
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• 2012

The effects of sheep urine and dung patches on methane ($CH_4$) and carbon dioxide ($CO_2$) fluxes were investigated during the summer-autumn in 2010, to evaluate their contribution to climate change in a desert grassland in Inner Mongolia, China. Results indicate that the cumulative $CH_4$ emissions for dung patches, urine patches and control plots were -0.076, -0.084, and -0.114 g/$m^2$ and these were net $CH_4$ sinks during the measured period. The level of $CH_4$ intake from urine and dung plots decreased 25.7%, and 33.3%, respectively, compared with a control plot. $CO_2$ fluxes differed (p<0.01) in urine plots, with an average of 569.20 mg/$m^2$/h compared with control plots (357.62 mg/$m^2$/h) across all sampling days. Dung patches have cumulative $CO_2$ emissions that were 15.9% higher compared with the control during the 55-d period. Overall, sheep excrement weakened $CH_4$ intake and increased $CO_2$ emissions.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1008-1014
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• 2012

The amount of domestic carbon dioxide emissions is more than 600 million tons/year. The emitted $CO_2$ should be captured and stored, however, suitable storage sites have not been found yet. A lot of researches on the conversion of captured carbon dioxide to useful carbon source have been conducted. The purpose of this study is to convert stable carbon dioxide to useful resources using less energy. For this purpose reducing gas and metallic oxide (activator) are required. Hydrogen was used as reducing gas and cobalt ferrite was used as activator. Considering that activator has different physical properties depending on synthesis methods, activator was prepared by hydrothermal synthesis and solid method. Decomposition characteristics of carbon dioxide were investigated using synthesized powders. Temperature programmed reduction/oxidation (TPR/TPO) and thermogravimetric analyzer (TGA) device were used to observe the decomposition characteristics of carbon dioxide. Activator prepared by solid method with 5 and 10 wt% CoO content showed an excellent performance. In TGA experiments with samples prepared by the solid method, reduction by hydrogen was 29.0 wt% and oxidation by $CO_2$ was highest in 27.5 wt%. 95% of adsorbed $CO_2$ was decomposed with excellent oxidation-reduction behaviors.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.221-223
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• 2012

Since gas turbine using biogas can reduce carbon dioxide ($CO_2$), the biogas gas turbine is becoming more attractive to renewable energy utilization business sector. Natural gas and $CO_2$ mixture was used to simulate the biogas fuel. At the experiments pressure losses, pattern factor, and emissions were measured. The results revealed that methane concentrations of the fuel mixture showed little effects on the combustor performance except emissions. As methane concentrations in fuel decreased, emissions measured at the exit of the combustor decreased.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.77-82
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• 2009

Many countries have been interested in sustainable development of buildings for environmental preservation. Thus it is significant to assess building envelopes in terms of $CO_2$ emissions owing to Kyoto Protocol. In this paper, a Double Skin Facade(DSF) installed in a general office building was assessed by $CO_2$ emissions(one of the performance-based assessment). To predict $CO_2$ emissions caused by the building energy consumption, the dynamic simulation program(Energy Plus) and $CO_2$ emission factor was used. Because DSF has various airflow regimes, pre-simulation runs were conducted to decide proximate optimal airflow regimes depending on seasonal variation. It is shown that the DSF can achieve 17.1-36.5% of annual energy savings.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.4
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• pp.113-119
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• 2001

Ammonia emissions during composting of hog manure mixed with sawdust were studied in four runs comprising a total of 22 pilot-scale reactor vessels. These four runs extended previous work and both verified and extended the previous conclusions. The pilot-scale vessels were 205 L insulated stainless steel drums that were aerated either continuously (high/low thermostatically controlled fans) or intermittently (5 min high fan 55 min off). Temperature ammonia emissions air flow rates carbon dioxide production and oxygen utilization moisture and dry matter reduction initial and final chemical compositions were measured. Ammonia emissions from the intermittently aerated vessels were only about 50% as great as those from the continuously aerated ones but this was found to be a result more related to total air flow than to aeration technique. All of the data for total result more related to total air flow were fitted with a linear regression line y=0.139x+29.835 where y is ammonia expressed as g of N and x is air flow in kg with $R^2$=0.6808. this general trend indicates that about 50% reduction in ammonia emissions can be achieved with 75% reduction in air flow. For the aeration techniques used the minimum oxygen level in te exhaust gas from the vessels was 5% and this is probably a resonable lower limit constraining air flow reduction. However within this constraint lower air flow now appears to be a technique that can reduce odorous ammonia emissions.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.801-808
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• 2021

The issue of the relationship between environmental degradation and human health has been widely addressed by medical doctors. However, economists have sparsely debated it. The release of carbon dioxide (CO2) into the air can cause several environmental problems and, thus, it can affect human health. Therefore, it is imperative to examine the effect of CO2 emissions on life expectancy in the D-8 countries (Malaysia, Indonesia, Bangladesh, Nigeria, Egypt, Iran, Pakistan, and Turkey) from 1992 to 2017. The panel ARDL method is employed and, then, the PMG estimator is selected. The results show that economic growth, population growth and health expenditure can significantly and positively affect life expectancy, but CO2 emissions can have a significant and negative effect on life expectancy. Since, the major findings reveal that life expectancy can be explained by CO2 emissions. Hence, it is important to formulate policies on reducing CO2 emissions so that life expectancy will not be affected. Energy diversification policies should be formulated or improved in some countries. This is to ensure that the countries are not highly dependent on non-renewable energy that can harm the environment. The government should increase its expenditure on the health sector to save more lives by extend human lifespan.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.269-277
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• 2022

Human activities account for approximately two-thirds of global methane emissions, wherein the livestock sector is the single massive methane emitter. Methane is a potent greenhouse gas of over 21 times the warming effect of carbon dioxide. In the rumen, methanogens produce methane as a by-product of anaerobic fermentation. Methane released from ruminants is considered as a loss of feed energy that could otherwise be used for productivity. Economic progress and growing population will inflate meat and milk product demands, causing elevated methane emissions from this sector. In this review, diverse approaches from feed manipulation to the supplementation of organic and inorganic feed additives and direct-fed microbial in mitigating enteric methane emissions from ruminant livestock are summarized. These approaches directly or indirectly alter the rumen microbial structure thereby reducing rumen methanogenesis. Though many inorganic feed additives have remarkably reduced methane emissions from ruminants, their usage as feed additives remains unappealing because of health and safety concerns. Hence, feed additives sourced from biological materials such as direct-fed microbials have emerged as a promising technique in mitigating enteric methane emissions.

• Advances in Computational Design
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• v.8 no.4
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• pp.295-307
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• 2023

This paper presents an optimization of the reinforced concrete ribbed slab in terms of minimum CO₂ emissions and an economic justification of the final optimal design. The design variables are six geometry variables including the slab thickness, the ribs spacing, the rib width at the lower and toper end, the depth of the rib and the bar diameter of the reinforcement, and the seventh variable defines the concrete strength. The objective function is considered to be the minimum amount of carbon dioxide gas (CO₂) emission and at the same time, the optimal design is economical. Seven significant design constraints of American Concrete Institute's Standard were considered. A robust metaheuristic optimization method called improved dolphin echolocation and ant colony optimization (IDEACO) has been used to obtain the best possible answer. At optimal design, the three most important sources of CO₂ emissions include concrete, steel reinforcement, and formwork that the contribution of them are 63.72, 32.17, and 4.11 percent respectively. Formwork, concrete, steel reinforcement, and CO₂ are the four most important sources of cost with contributions of 67.56, 19.49, 12.44, and 0.51 percent respectively. Results obtained by IDEACO show that cost and CO₂ emissions are closely related, so the presented method is a practical solution that was able to reduce the cost and CO₂ emissions simultaneously.

• Spatial Information Research
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• v.19 no.6
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• pp.11-18
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• 2011

Urban space is the main contributor of greenhouse gas emissions, a primary cause of global warming. In order to reduce greenhouse gas emissions, planning at a city-level is necessary. The aim of this research is to develop a carbon emission model which can be used to create and manage urban spaces. In order to achieve this aim, the following methodologies were utilized. First, urban planning criteria related to population, landuse, and activity level were selected through theoretical speculation. Second, carbon dioxide emission was calculated based on electricity, gas energy, heating, petroleum, and water usages. Third, Seoul was selected as a case study city, and a carbon emission model was developed through a relational analysis between Seoul's urban planning criteria and carbon emissions. Thus far, various efforts have been made to respond to climate changes in urban spaces, but these have been limited to analyzing contributing factors in terms of their total amounts of carbon emissions in the entire city. However, the carbon emission model of this study is derived from urban planing criteria at a detailed scale. This sets our study apart from other studies by demonstrating a specific model in a local setting which can be utilized for lowering carbon emissions at a city level.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.2
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• pp.181-187
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• 2003

Biodiesel fuel as an alternative fuel for diesel engine has a great possibility to solve the problems such as air pollution. It is a domestically produced, renewable fuel that can be manufactured from vegetable oils, used vegetable oils, or animal fats. In this study, the usability of biodiesel fuel derived from rice bran oil as an alternative fuel for diesel engines was investigated in agricultural diesel engine. Emissions were characterized with neat biodiesel fuel and with a blend of biodiesel fuel and conventional diesel fuel. Since the biodiesel fuel includes oxygen of about 11%, it could influence the combustion process strongly. So, the use of biodiesel fuel resulted in lower emissions of carbon monoxide, carbon dioxide, and smoke emissions without any increase of oxides of nitrogen. It is concluded that biodiesel fuel can be utilized effectively as a renewable and an environmentally Innocuous fuel for diesel engine.