A Review on International Carbon Credit Certification Methodologies for Biochar as a Soil Amendment

한경화,윤석인,곽진협,이선일 한국토양비료학회 2023 한국토양비료학회지 Vol.56 No.4

The high organic carbon (Corg) sequestration ability of biochar can greatly contribute to atmospheric CO2 removal for global C neutrality. These climate-positive services of biochar are traded as C credits on international C trading platforms through reliable methodologies. Here, we reviewed the international biochar C credit certification methodologies and quality standards to build foundations for biochar C credit trading in Korea. The quality of biochar includes the quantity of Corg sequestered over 100 years, the content of toxic contaminants below their threshold values, and the biochar properties related to soil fertility, as described by European Biochar Certificate (EBC) and International Biochar Initiative (IBI) certification guidelines. The higher amount of Corg sequestered over 100-year in biochar is ascribed to the lower the molar H/Corg and O/ Corg ratios, resulting from pyrolysis of feedstock at a high temperature over 350°C. For assuring the permanence of biochar, the threshold value of molar H/Corg ratio is 0.7 in both EBC and IBI. Besides, EBC standards also have the threshold value 0.4 of a molar O/Corg ratio for all biomass and require a pyrolysis condition of exceeding 500°C for 3 min at minimum for animal-derived biomass. Quality-certified biochar can be used for C credits. Biochar C credit is the amount of net CO2-eq removed over 100-year by the biochar activity, i.e., biochar Corg sequestered over 100-year minus greenhouse gas (GHG) emissions over the biochar life cycle. The three voluntary C credit trade platforms with their own biochar methodologies are Puro.earth with life cycle assessment, Carbonfuture with C-sink certification, and Verra with UNFCCC Clean development mechanism (CDM) methodology. All three methodologies present standards for permissible biomass for feedstock, energy efficiency and by-product treatment for production, permissible matrices and tracking system for end use, and the third-party verrification. On a regional basis in Korea, where biochar feedstock is mainly biogenic waste, GHG emissions during biochar lifetime mainly depend on the production stage. In pyrolysis facilities that meet EBC and Verra’s high-tech standards, GHG emissions during the production stage could be assumed to be very low. However, low-tech facilities with high GHG emissions during biochar production could deteriorate biochar C credits. Therefore, securing biochar C credits could be achieved through the modernization of pyrolysis facilities. Besides, it is essential to establish a process-oriented measurement, reporting, and verification systems, to ensure scientific reliability of biochar C credit certification

How to Develop, Validate, and Compare Clinical Prediction Models Involving Radiological Parameters: Study Design and Statistical Methods

한경화,송기준,최병욱 대한영상의학회 2016 Korean Journal of Radiology Vol.17 No.3

Clinical prediction models are developed to calculate estimates of the probability of the presence/occurrence or future course of a particular prognostic or diagnostic outcome from multiple clinical or non-clinical parameters. Radiologic imaging techniques are being developed for accurate detection and early diagnosis of disease, which will eventually affect patient outcomes. Hence, results obtained by radiological means, especially diagnostic imaging, are frequently incorporated into a clinical prediction model as important predictive parameters, and the performance of the prediction model may improve in both diagnostic and prognostic settings. This article explains in a conceptual manner the overall process of developing and validating a clinical prediction model involving radiological parameters in relation to the study design and statistical methods. Collection of a raw dataset; selection of an appropriate statistical model; predictor selection; evaluation of model performance using a calibration plot, Hosmer-Lemeshow test and c-index; internal and external validation; comparison of different models using c-index, net reclassification improvement, and integrated discrimination improvement; and a method to create an easy-to-use prediction score system will be addressed. This article may serve as a practical methodological reference for clinical researchers.

임신기간에 따른 정상 임부가 자각한 피로 정도의 차이

한경화,배효숙,기부성,최선희,김선희,장희영,강지호 이화여자대학교 의과대학 1999 임상간호연구지 Vol.4 No.-

배움중심 수업과 교육과정 재구성

한경화 한국교원교육학회 2015 한국교원교육학회 학술대회자료집 Vol.2015 No.11

Tillage Effects on Evapotranspiration of Three Different Paddy Soils in Spring Season as Tested by Monolithic Weighable Lysimeters

한경화,서미진 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.2

This study was conducted to evaluate the effect of tillage in spring season before rice cultivation on evapotranspiration (ET) of three different paddy soils. Precision weighing lysimeters, filled with three undisturbed paddy soils, were used, and each texture was silty clay loam, loam, and sandy loam. For tillage treatments, the hand tillage (HT) was conducted to a depth of 8 cm by using a spatula with a 5 cm width on Mar. 8, 2016. The no-tillage (NT) treatments were continuously kept as no-tillage conditions during the study period. In 2016 spring of this experimental field, two contrary periods in weather condition, dry period from Mar. 8 to Apr. 5 and rainy period from Apr. 6 to Apr. 30, were used to analyze the effects of tillage on soil water status and evapotranspiration in paddy soils. In dry period with rare rainfall, HT treatment had lower evapotranspiration loss than NT treatment except sandy loam soil. Especially, the soil water tension difference over the dry period between HT and NT was highest in silty clay loam soils, probably due to transection of crack by tillage. On the other hand, the significant tillage effect on ET reduction in all soils over total period, dry and rainy periods, was not observed with high flucturation of weed biomass. This is probably not only because frequent rainfall events in rainy period could cause the reconnection of capillaries through water dispersion of clods, but also because nutrient mineralization at rewetting after surface tillage could promote ET through better weed growth. Nevertheless, in drought condition, tillage operation in early spring could be useful to decease water loss by evapotranspiration.

Nitrogen and Phosphorus Runoff Loss during Summer Season in Sandy Loam Red Pepper Field as Affected by Different Surface Management Practices in Korea

한경화,노희명 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.6

A field study was conducted to determine the runoff loss of N and P in small scale of red pepper field plots (10% slope), consisting of three different plots with black polyethylene vinyl mulching (mulching), ridge without mulching (ridge), and flat without ridge and mulching (flat). Composted manure and urea as a basal application were applied at rates of 20 MT ha-1 and 93 kg N ha-1, respectively. Urea at 189 kg N ha-1 and fused phosphate at 67 kg P2O5 ha-1 were additionally applied on June 25 with different fertilization methods, broadcast application in flat plot and hole injection in ridge and mulching plots. Plant uptake of N and P was positively correlated with their respective concentrations in surface soil: mulching > ridge > flat plots. The runoff loss by soil erosion was higher in flat plot than ridge and mulching plot with contour line. Nitrate loss by the runoff water had no significant differences among three surface management practices, but the higher average value in ridge and mulching plots than flat plot. Especially, the flat plot had no phosphate loss during summer season. This is probably due to low labile P content in surface soil of flat plot. In the summation of soil and water loss, flat plot was higher in N and P loss than ridge and mulching plot with contour line. Nevertheless, the nitrate and phosphate loss by runoff water could be more important for non-point source management because the water could meet the river easier than eroded soil because of re-deposition around slope land.

포화 수리전도도와 불투수층 깊이에 따른 우리나라 토양의 수문학적 토양군 분류

한경화,정강호,조희래,이협성,옥정훈,서미진,장용선,서영호,Han, Kyunghwa,Jung, Kangho,Cho, Heerae,Lee, Hyubsung,Ok, Junghun,Seo, Mijin,Zhang, Yongseon,Seo, Youngho 한국농공학회 2017 한국농공학회논문집 Vol.59 No.5

Hydrologic soil group is one of the important factors to determine runoff potential and curve number. This study was conducted to classify the hydrologic soil groups of Korean soils by considering saturated hydraulic conductivity and depth of impermeable layer. Saturated hydraulic conductivity of Korean soils was estimated by pedotransfer functions developed in the previous studies. Most of paddy soils were classified as D type due to shallow impermeable layer and low saturated hydraulic conductivity in B soil horizon. For upland and forest, soils classified to A and D types increased compared with former classification method because underestimated permeabilities and overestimated drainages were corrected and rock horizon in shallow depth was regarded as impermeable layer. Soils in mountainous land showed the highest distribution in A type, followed by D type. More than 60 % of soils in mountain foot-slope, fan and valley, alluvial plains, and fluvio-marine deposits were classified to D type because of land use such as paddy and upland.

공간마케팅 전략적 요소를 적용한 가구 쇼룸 디자인에 관한 연구

한경화,황연숙 한국실내디자인학회 2023 한국실내디자인학회논문집 Vol.32 No.5

Due to recent improvements in income levels, cultural standards, and an increasing desire for an enhanced quality of life, consumer trends have shifted towards experience-centric consumption. At the same time, the furniture market is growing due to the diversification of lifestyles. Furniture showrooms, as offline spaces for displaying and selling furniture, need to develop competitive design strategies to stand out from other brands. Therefore, The purpose of this study is to analyze the design of furniture showrooms by deriving spatial marketing strategy elements, which can serve as basic data for competitive furniture showroom spaces that can meet consumer needs. The research extracted four strategic elements of space marketing: Spatial elements, Sensory elements, Narrative elements, and Relational elements, and developed a checklist based on these elements. The analysis focused on furniture showrooms of standalone brand furniture located in the metropolitan area. The findings of this study are as follows: In terms of space marketing, Spatial Elements were found to be the most prominent, with showrooms predominantly utilizing an open and inviting exterior to attract consumer interest from the outside. Relational Elements were the least emphasized, indicating a lack of programs aimed at enhancing consumer understanding of the brand and products and effectively conveying brand values and purpose.

분과발표 3 : 경도장애 학생들의 수학적 문제해결을 위한 폴리아의 전략 효과 연구

한경화,김영옥 한국수학교육학회 2016 수학교육 학술지 Vol.2016 No.1

친환경농업 - 토양 떼알구조 안정화로 온실가스 줄인다.

한경화,Han, Gyeong-Hwa 전국농업기술자협회 2010 농업기술회보 Vol.47 No.2