• 농업과학연구
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• 제44권4호
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• pp.463-476
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• 2017

Climate change is considered as the greatest threat to our future and descendants. The Korean government has set a target for 2030 to reduce emission of greenhouse gases (GHGs) by 37% from the business-as-usual levels which are projected to reach 851 million metric tons of $CO_2eq$ (Carbon dioxide equivalent). In Korea, GHGs emission from agriculture account for almost 3.1% of the total of anthropogenic GHGs. The GHGs emitted from agricultural land are largely classified into three types: carbon dioxide ($CO_2$), methane ($CH_4$), and nitrous oxide ($N_2O$). In Korea, rice paddies are one of the largest agricultural $CH_4$ sources. In order to analyze domestic research trends related to $CH_4$ emission from rice paddies, 93 academic publications including peer reviewed journals, books, working papers, reports, etc., published from 1995 to September 2017, were critically reviewed. The results were classified according to the research purposes. $CH_4$ characteristics and assessment were found to account for approximately 65.9% of the research trends, development of $CH_4$ emission factors for 9.5%, $CH_4$ emission reduction technology for 14.8%, and $CH_4$ emission modeling for 6.3%, etc. A number of research related to $CH_4$ emission characteristics and assessment have been studied in recent years, whereas further study on $CH_4$ emission factors are required to determine an accurate country-specific GHG emission from rice paddies. Future research should be directed toward both studies for reducing the release of $CH_4$ from rice paddies to the atmosphere and the understanding of the major controlling factors affecting $CH_4$ emission.

• 환경영향평가
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• 제17권2호
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• pp.113-124
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• 2008

A worldwide trend of permitting system for industrial installation to achieve a high level of protection of the environment has been moved from single media to multimedia in approach. The Council of the European Community issued the Directive 96/61/EC, the IPPC Directive, concerning integrated pollution prevention and control in 1996. The IPPC Directive is one of the most ambitious legal measures that the European Union (EU) has initiated with a view to applying the prevention principle for industrial activities. The IPPC aims to achieve the integrated prevention and reduction of environmental pollution emitted by those industrial installations with a higher potential of emissions to the environment. Organization for Economic Cooperation and Development (OECD) recommended on Environmental Performance Reviews of Korea in 2006 that IPPC permitting concept should be considered for large stationary sources at the national and regional levels. Any Korean law doesn't provide for integrated pollution control with a single process covering all pollution from economic activities. However, one exception might be the "environmentally-friendly companies" certification scheme, introduced in 1995, in which participants agree to meet targets beyond the legal emission limit values in exchange for government technical and financial support to operate environmental management systems. The other exception might be Environmental impact assessment (EIA) of projects, in 1977, which has been strengthened and reinforced to be more preventive through development of the prior environmental review system (PERS) in 1999. The aim of this work is to introduce the contents of IPPC Directive at the viewpoint of Korea policy and to survey the integrated approaching concept of Environmentally-Friendly Companies (EFC) Certification Scheme and EIA policy of Korea. The study will be helpful in the future to prepare the infrastructure of integrated permitting system and to enforce the integrated permit which the authorities of local government issues on industrial activities. It can be said that the data calculated through both EFC Certification Scheme and EIA will be discussed as worthful information to determine Korean BAT reference notes for integrated permitting process.

• 한국환경농학회지
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• 제39권4호
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• pp.297-304
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• 2020

BACKGROUND: Emission of nitrous oxide (N2O) from the soil is expected to depend on the types of nitrogen fertilizer used. Biochar has recently been proposed as a potential mitigation of climate change by reducing the N2O emission. Although laboratory studies reported that biochar applications could reduce N2O emission, the number of field-based studies is still limited. Therefore, a field experiment was conducted to investigate the effect of biochar on N2O emission when different nitrogen fertilizers were applied in corn cultivated field. METHODS AND RESULTS: The field experiment consisted of six treatments: urea fertilizer without biochar (U), ammonium sulfate fertilizer without biochar (A), oil cake fertilizer without biochar (O), urea fertilizer with biochar (U+B), ammonium sulfate fertilizer with biochar (A+B), and oil cake fertilizer with biochar (O+B). Biochar was applied at a rate of 10 t/ha. Greenhouse gas fluxes were measured during growing seasons using static vented chambers. The cumulative N2O emissions were 0.99 kg/ha in the U, 1.23 kg/ha in the A, 3.25 kg/ha in the O, 1.19 kg/ha in the U+B, 0.86 kg/ha in the A+B, and 1.55 kg/ha in the O+B. CONCLUSION: It was found that N2O emission was related to application of both nitrogen fertilizer type and biochar. In particular, the N2O reduction effect was the highest in the corn field incorporated with biochar when oil cake was applied to the soil.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2001년도 추계학술강연 및 발표대회
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• pp.7-7
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• 2001

The increasing interest in light weight materials coupled to the need for cost -effective processing have combined to create a significant opportunity for aluminum P/M. particularly in the automotive industry in order to reduce fuel emissions and improve fuel economy at affordable prices. Additional potential markets for Al PIM parts include hand tools. Where moving parts against gravity represents a challenge; and office machinery, where reciprocating forces are important. Aluminum PIM adds light weight, high compressibility. low sintering temperatures. easy machinability and good corrosion resistance to all advantages of conventional iron bm;ed P/rv1. Current commercial alloys are pre-mixed of either the AI-Si-Mg or AL-Cu-Mg-Si type and contain 1.5% ethylene bis-stearamide as an internal lubricant. The powder is compacted in closed dies at pressure of 200-500Mpa and sintered in nitrogen at temperatures between $580~630^{\circ}C$ in continuous muffle furnace. For some applications no further processing is required. although most applications require one or more secondary operations such as sizing and finishing. These sccondary operations improve the dimension. properties or appearance of the finished part. Aluminum is often considered difficult to sinter because of the presence of a stable surface oxide film. Removal of the oxide in iron and copper based is usually achieved through the use of reducing atmospheres. such as hydrogen or dissociated ammonia. In aluminum. this occurs in the solid st,lte through the partial reduction of the aluminum by magncsium to form spinel. This exposcs the underlying metal and facilitates sintering. It has recently been shown that < 0.2% Mg is all that is required. It is noteworthy that most aluminum pre-mixes contain at least 0.5% Mg. The sintering of aluminum alloys can be further enhanced by selective microalloying. Just 100ppm pf tin chnnges the liquid phase sintering kinetics of the 2xxx alloys to produce a tensile strength of 375Mpa. an increilse of nearly 20% over the unmodified alloy. The ductility is unnffected. A similar but different effect occurs by the addition of 100 ppm of Pb to 7xxx alloys. The lend changes the wetting characteristics of the sintering liquid which serves to increase the tensile strength to 440 Mpa. a 40% increase over unmodified aIloys. Current research is predominantly aimed at the development of metal matrix composites. which have a high specific modulus. good wear resistance and a tailorable coefficient of thermal expnnsion. By controlling particle clustering and by engineering the ceramic/matrix interface in order to enhance sintering. very attractive properties can be achicved in the ns-sintered state. I\t an ils-sintered density ilpproaching 99%. these new experimental alloys hnve a modulus of 130 Gpa and an ultimate tensile strength of 212 Mpa in the T4 temper. In contest. unreinforcecl aluminum has a modulus of just 70 Gpa.

• Asian-Australasian Journal of Animal Sciences
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• 제10권1호
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• pp.35-46
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• 1997

An experiment with growing bulls were conducted to determine the effect of supplementation of a straw (S) with 15% molasses and 3% urea as an intimate mix (UMS) on its dry matter (DM) intake and digestibility (DMD) and reduction of methane ($CH_4$) production from fermentation in vitro of the straw. In the next experiment, the feeding of the UMS was compared with that of the feeding of molasses and urea in meals (DS) or in lick blocks (DSUMB) as supplements to straw. The UMS feeding increased daily intake of straw DM ($89.5 g{\cdot}kgW^{-0.75}$, p < 0.01) and digestible crude protein (DCP 333 g, p < 0.001) and nitrogen (N) balances ($508mg{\cdot}kgW^{-0.75}{\cdot}d^{-1}$, p < 0.01) of the bulls than the feeding of 'S' ($65g{\cdot}kgW^{-0.75}$, 55 g and $8.0mg{\cdot}kgW^{-0.75}{\cdot}d^{-1}$, respectively). It also increased the digestibility of DM ($594g{\cdot}kg^{-1}$, p < 0.05), organic matter (OM, $641g{\cdot}kg^{-1}$, p < 0.05), CP ($619g{\cdot}kg^{-1}$, p < 0.001) and acid detergent fibre (ADF, 773, p < 0.05). The $CH_4$ emitted per g of DOM apparently fermented in the rumen (DOMR) was 91.0 ml in the 'S' and reduced (p < 0.05) to 61.6 ml in the UMS. The feeding of the UMS when compared with that of the DS or DSUMB also gave a higher straw intake (1.77% of live weight, LW, p <0.01) and ADF digestibility ($516g{\cdot}kg^{-1}$, p < 0.05) than the other diets (1.52% or 1.55% LW and 472 or $490g{\cdot}kg^{-1}$, respectively) in association with the increased microbial N yield in the rumen (14.1, 5.62 or $17.0g{\cdot}kg^{-1}$ DOMR, respectively, p < 0.05), daily LW gains (233, 125 or 93 g, respectively, p < 0.05) and feed conversion ratios of the diets (26.0, 56.1, or 57.6 g feed/g LW gain, p > 0.05, respectively). It can be concluded that molasses and urea feeding as an intimate mix with straw (UMS) increased its digestion and intake in association with a reduced methane emissions in the rumen. When compared with that of their feeding in meals or in lick blocks as supplements to straw the UMS gave the highest straw in take and digestion and live weight gains of growing bulls concurring the finding that the UMS system may be the best way of molasses and urea feeding to ruminants fed straws.

• 한국환경농학회지
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• 제42권2호
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• pp.159-167
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• 2023

Food waste (FW) emissions in South Korea amounted to 4.77 million tons in 2021, and continue to increase. Various technologies have been developed to treat FW, with recent research focusing on biochar production through pyrolysis to reduce FW. However, the agricultural application of food waste-biochar (FWBC) is limited by the salt accumulated during pyrolysis. This study investigated salt removal from and the kinetic characteristics of FWBC, and subsequently evaluated its agricultural applications. FW was pyrolyzed at 350℃ for 4 h, and subsequently washed for 0.1, 0.25, 0.5, 0.75, 1, 5, 15, and 30 min to remove salt. FWBC had a salt concentration of 5.75%, which was effectively removed through washing. The salt concentration decreased rapidly at the beginning (1 min) and then slowly decreased, unlike in FW, in which the salt decreased continuously and slowly. The salt removal speed constant (K) was 1.5586 (Stage 1, FWBC) > 0.0445 (Stage 2, FWBC) > 0.0026 (FW). In a lettuce cultivation experiment, higher biomass was achieved using washed FWBC than when using unwashed FWBC and FW, and soil properties were improved. Overall, these findings suggest that although FW reduction using pyrolysis causes a salt accumulation problem, the salt can be effectively removed through washing. The use of washed FWBC can enhance plant growth and soil properties.

• 한국가스학회지
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• 제27권4호
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• pp.85-91
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• 2023

본 연구에서는 GT24 가스터빈의 1단 연소기인 EV버너를 대상으로 수소연료 혼소에 대한 화염거동, 연소 진동 및 NOx 배출 특성에 대한 실험적 연구를 수행하였다. 수소 혼소율이 증가할수록 NOx 배출 농도가 증가하는 결과를 확인하였다. 이러한 변화는 연료 밀도 변화로 인한 침투깊이 변화, 화염전파속도 증가에 따른 화염위치 변화에 기인한 연료 혼합도 감소와 연소진동으로 인한 시간적 혼합도 섭동 영향이 복합적으로 작용한 결과로 판단되었다. 1.3~3.1bar 범위의 가압 시험을 통해 고압 운전 조건의 NOx 배출 특성을 예측하고 이를 토대로 천연가스용 EV 버너의 수소혼소 한계를 평가하였다.

• 유통과학연구
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• 제13권10호
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• pp.123-133
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• 2015

Purpose - The Korean government has devised intermodal transportation policies and granted subsidies to shippers and logistics companies that made a conversion of transportation means through the policies. This provides support by expanding the complex uniform railroad transportation and overhauling the deteriorated railroad facilities. As for 2013, however, the freight transportation percentage of railroad was 4.5% in tons and 8.5% in ton kilometers. Meanwhile, since the 1990s, developed countries such as the U.S. and Europe have been trying to expand intermodal freight transport with a legal and institutional support to build a logistics system corresponding with social and economic environmental changes. In this study, I set out to examine the effects of the intermodal freight transport policies in the EU and the U.S., and to explore the direction of setting up a rail intermodal transport system in South Korea. Research design, data, and methodology - The paper used a qualitative research methodology through the literature review. First, was an overview of Intermodal transportation in the EU, U.S. and UN. Second, it describes the development of transport in Europe and the U.S. with particular emphasis on intermodal freight transport. Third, it explores the direction of setting up a intermodal freight transport in South Korea. The last section contains concluding remarks. Results - As for the EU, it has been promoting integration between transport and intermodal logistics network designs while utilizing ITS or ICT and supports for rail freight intermodal by giving reduction to a facilities fee or subsidizing for rail freight in order to minimize the cost of external due to freight transport. On the other hand, as for the U.S., it has been made up of an industrial-led operating project and has been promoting it to improve accessibility between intermodal hubs and cargo terminals through intermodal corridor program, and an intermodal cargo hub access corridor projects, etc. Moreover, it has tried to construct intermodal transport system using ITS or ICT and to remove Barrier. As a result, in these countries, the proportion of intermodal freight transport is going to be the second significant transport compared with rail and maritime transport. An Effective rail intermodal transport system is needed in South Korea, as seen in the case of these countries. In order to achieve this object, the following points are required to establish radical infrastructure policy; diversify investment financing measures taken under public-private partnerships, legal responsibilities, improvement of utilization of existing facilities to connect the railway terminal and truck terminal, and enhancement service competitiveness through providing cargo tracking and security information that combines the ITS and ICT. Conclusions - This study will be used as a basis for policy and support for intermodal freight transport in South Korea. In the future, it is also necessary to examine from the perspective of the shipper companies using the rail intermodal transport, ie, recognition of shipper, needed institutional supports, and transportation demand forecasting and cost-effective analysis of the railway infrastructure systems improvement.

• 한국기후변화학회지
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• 제8권1호
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• pp.21-30
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• 2017

Recently, There has been much discussed about unused space. This space can be used in a variety of ways. Utilizing it as a facility, craft shop, and utilizing renewable energy generation facilities. Especially, in terms of climate change should be supplied renewable energy. Renewable energy needs to be developed in terms of responding to climate change, and the recent Paris agreement is also emphasizing the importance of renewable energy. In particular, renewable energy needs to be widely disseminated. And renewable energy is limited space. In this regard, idle land can provide opportunities for securing new renewable energy generation facilities. The introduction of new and renewable energy facilities in idle space can enhance the self-sufficiency rate of the local community, which is significant in terms of responding to climate. In this study, to investigate the possibility of utilizing a unused space for a photovoltaic power generation facility, we investigated the amount of electricity which could be generated through photovoltaic power generation, and the economic effects, using a RETScreen model. The results showed that 9,738 MWh of power can be generated and that $4,540tCO_2eqcan$ be saved. Regarding the economic effect, the net present value of the facility was shown to be 2,247,389,020 KRW. As the net present value was shown to be positive, we believe that the installation of a photovoltaic power generation facility in an unused space would have a positive economic effect. We found the net present value following the fluctuation of the SMP price to be positive, though there was some variation. However, as the economic efficiency was shown to be low because the net present value in relation to the maintenance costs was negative, we believe that maintenance costs must be taken fully into account when evaluating economic efficiency. In particular, as subsidies can be used to cover maintenance costs which must be factored into photovoltaic power generation, we believe that photovoltaic power generation can have an economic effect. Because spaces not currently in use can have a positive economic effect as renewable energy power generation facilities, and can also contribute to the reduction of greenhouse gas emissions, unused spaces are thought to greatly help local governments to cope with climate change as well as reinforcing their related capabilities. We believe our study will help local governments with decisions relating to unused real estate utilization in the future.

• 광물과산업
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• 제26권
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• pp.1-12
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• 2013

In this study, an accelerated carbonation process was applied to stabilize hazardous heavy metals of industrial solid waste incineration (ISWI) bottom ash and fly ash, and to reduce $CO_2$ emissions. The most commonly used method to stabilize heavy metals is accelerated carbonation using a high water-to-solid ratio including oxidation and carbonation reactions as well as neutralization of the pH, dissolution, and precipitation and sorption. This process has been recognized as having a significant effect on the leaching of heavy metals in alkaline materials such as ISWI ash. The accelerated carbonation process with $CO_2$ absorption was investigated to confirm the leaching behavior of heavy metals contained in ISWI ash including fly and bottom ash. Only the temperature of the chamber at atmospheric pressure was varied and the $CO_2$ concentration was kept constant at 99% while the water-to-solid ratio (L/S) was set at 0.3 and $3.0dm^3/kg$. In the result, the concentration of leached heavy metals and pH value decreased with increasing carbonation reaction time whereas the bottom ash showed no effect. The mechanism of heavy metal-stabilization is supported by two findings during the carbonation reaction. First, the carbonation reaction is sufficient to decrease the pH and to form an insoluble heavy metal-material that contributes to a reduction of the leaching. Second, the adsorbent compound in the bottom ash controls the leaching of heavy metals; the calcite formed by the carbonation reaction has high affinity of heavy metals. In addition, approximately 5 kg/ton and 27 kg/ton $CO_2$ were sequestrated in ISWI bottom ash and fly ash after the carbonation reaction, respectively.