• 한국농공학회논문집
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• 제64권6호
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• pp.25-34
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• 2022

Recently, as a study to air cooled slag, which is an industrial by-product, research is being proceed to use it as a material for concrete. In this study, the workability, air content, compressive strength, CO₂ emission and economic feasibility of concrete were analyzed when air cooled slag, an industrial by-product, was applied as aggregate for rural road pavement concrete. As a result of the analysis, both the slump and air contents test results of concrete using the air cooled slag aggregate satisfied the target values, and the compressive strength was increased when the air cooled slag aggregate was used compared to when the natural aggregate was applied. On the other hand, the largest amount of CO₂ emission by raw material was found in aggregate. The carbon emission of rural road pavement concrete using air cooled slag aggregate increased when the Korean LCI DB was applied compared to when natural and crushed aggregates were applied, and the emission decreased when the German LCI DB was applied. This results are due to differences in the viewpoints of industrial by-products. However, considering the recycling of waste from the environmental aspect, it is necessary to simultaneously review the CO₂ emission and recycling aspects in the future. Also, the application of air cooled slag aggregate had the effect of improving the economic efficiency of rural road pavement concrete about 18.75%.

• BMB Reports
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• 제36권6호
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• pp.597-602
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• 2003

Acid phosphatases (APases) play a role in the release of phosphate in organic complexes in soil. We investigated tissue- and isoform-specific responses of APases to phosphorus (P) deficiency in three rice genotypes; Dasan-byeo, Sobi-byeo, and Palawan. The levels of shoot APase activity per protein were similar in the three genotypes. They significantly decreased with P deprivation that was longer than seven days. Root APase activity per protein was two- to three-fold higher in Dasan than in Sobi and Palawan. In all genotypes the APase activity increased in P-deficient plants, but the increase was higher in Sobi and Palawan. After 21 days of P deprivation, secreted APase activity increased more than eight-fold in Dasan and two-fold in Sobi and Palawan. Isoform profiles of shoot and root APases were most diverse in Dasan. The activities of the major isoforms in P-deficient shoots decreased in all three genotypes. Depending on the genotypes, further increases in constitutive isoforms and new induction of one to four isoforms occurred in P-deficient roots. The results indicate that tissue and genotype differences in the response of APase to P deficiency are primarily facilitated by the different responses of the isoforms.

• 한국농공학회논문집
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• 제48권5호
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• pp.73-80
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• 2006

The mono-layer cover system is composed of soils only as a filling material and various plants are planted on the surface to control the water balance in the cover system. In this paper, the mono-layer cover system was considered as an alternative landfill final cover system and developed a model that could utilize industrial by-product (especially, coal ash & phosphogypsum) as additive filling materials. The mixture of granite soil, coal ash, and phosphogypsum was placed as a cover material in a box constructed with cement. Laboratory tests were carried out to investigate the environmental effect on the utilization of coal ash & phosphogypsum and to determine the mxing ratio of each materials. In the leaching test, all materials showed lower heavy metal concentration than the threshold values of regulation. The optimum mixing ratio of materials which was applied to field model test was determined to soil (4) : coal ash (1) : phosphogypsum (1) on the volume base. Field model tests were continued from February to July, 2004 in the soil box that was constructed with cement block. It was verified that coal ash and phospogypsum mixed with soil was to be safe environmentally and the water balance of mono-layer cover system was reasonable.

• 대한인간공학회지
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• 제29권2호
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• pp.225-239
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• 2010

A high prevalence of farmer's work-related musculo-skeletal disorders (MSDs) have been reported in precedent studies. Risk factors - physical, chemical, biological, ergonomic risk factor etc. - in farm-work were identified by previous studies. To prevent farmers from exposing to them and reduce, Agricultural Safety Technology were introduced and used on farm. The purpose of this study is to review and summarize the agricultural safety technology on farm in Korea. According to strategy principles, this technology is classified as four criteria - workload reduction by reducing awkward posture, workload reduction by using manual material handling aids, Comfort improvement by protecting worker from hot, cold environment and work efficiency improvement by workplace redesign and cultivation modification. This technology includes transporting tools, working cloth, personal protective equipment, and pesticide-proof Clothing. Anthropometric study of Korean farmers was also carried out to support the development of equipment and clothes. In long terms, it needs to precaution activity from risk factors by using cultivation modification and working improvement. Although working condition gets better and workload reduce by this technology, it required customized safety technology in each crops - rice cultivation, horticulture and livestock farming. And farmers should use the assistive technology and participate voluntarily in ergonomic intervention program.

• 농업과학연구
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• 제46권4호
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• pp.931-939
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• 2019

Biochar is a solid carbon material made by pyrolyzing a biomass under limited oxygen conditions. Biochar has been reported to confer various benefits, such as increased soil productivity, pollutant absorption, and reduced greenhouse gas. In this study, oak pyrolyzed at 600℃ for 3 hours was either powdered or pelleted. Each of the biochar types was added to the soil at a rate of 2%. The control did not receive any biochar while a combination of the biochar and NPK treatment (biochar 2% + NPK) was also included. The cherry tomatoes were grown in greenhouse pots for 50 days to compare the growth characteristics of the different treatments. The cherry tomato with the powdered biochar 2% + NPK treatment had the heaviest plant fresh shoot weight of 276.4 g and the highest chlorophyll content of 59.3 SPAD. The control had the lightest plant fresh shoot weight of 44.2 g and a chlorophyll content of 26.5 SPAD. Both forms of biochar affected the chemical properties of the soil, increased the pH, electrical conductivity, available phosphate, total carbon and total nitrogen and positively influenced the cherry tomato growth and productivity. From the above results, therefore, both biochar forms are suited for use as soil amendments.

• Computers and Concrete
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• 제33권6호
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• pp.707-724
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• 2024

This paper proposes a study of cement replacement with rice husk ash (RHA) and eggshell ash (ESA) for enhanced mechanical properties of geopolymer (GP) concrete with and without admixture. The main objective is to investigate the mechanical properties of GP with various replacement levels of Pozzolana Portland cement by RHA and ESA. The GP resistance to durability is examined and impact of ash materials on concrete's durability performance is determined. The environmental benefits of using agricultural waste materials in GP manufacturing minimize cement usage and CO2 emissions. The goal is to assess value of RHA-ESA of building material, paving stones for structures to lessen environmental impact. The novelty lies in use of ESA and RHA as partial replacements for cement and investigation of admixtures to enhance concrete properties, and reduce environmental impact. The research contributes by introducing a novel approach to reducing cement consumption by using ESA and RHA to address environmental concerns. It also explores the potential benefits of admixtures improving concrete performance and reducing environmental pollution. A study is carried with and without impacts of admixture to find compressive strength of GP cubes. The cement has been replaced by RHA and ESA in the range of (2.5%+7.5%, 5%+5%, 7.5%+2.5) by weight of cement for M20 mix. The compressive strength (CS) and split tensile strength (STS) at 7days, 14 days and 28 days is obtained as 21 N/mm2 at 7.5%RHA+2.5%ESA and 2.3 at 7.5%RHA+2.5%ESA, 24 N/mm2 at 7.5%RHA+2.5%ESA and 2.3 at 7.5%RHA+2.5%ESA, 28 N/mm2 at 7.5%RHA+2.5%ESA and 2.8 at 7.5%ESA respectively with normal curing condition.

• 한국응용과학기술학회지
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• 제26권2호
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• pp.143-150
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• 2009

Today, wastes of much quantity by fast industrialization and increase in population, population concentration etc. of modem society are increasing. Much oyster shell is breeding by character and conduct of oyster-industry for a long time among them. Oyster shell which breed by-product in oyster cultivating industry that specific gravity of domestic seashore cultivating industry is high is causing environmental problem by problem and so on hindrance, nature spectacle's waste and health hygiene on administration if it is pollution of district along the coast fishing ground, number of public ownership being stored in open area in seashore. About new material just-in-time through recycling and he of oyster shell by these problem wide that study. Go forward more and investigate special quality that is oyster shell's physical chemistry red in this research and oyster shell oyster shell which cause several environmental problems developing ability agricultural chemicals that use this encapsulating micro by ability carrier that is environmentally application possibility examine wish to.

• 한국농공학회논문집
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• 제50권1호
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• pp.71-81
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• 2008

This research was focused on the new model and its utility value of environmental friendly backhouse that overcomes the weaknesses of traditional backhouse and modem backhouse. To develop the model, the characteristics, merits and demerits of backhouses and the effectives of additional materials were analyzed and the study result of Rhee etc.(2005) is based. The design drawing of an ecological backhouse was presented considering the sanitation, environment, economy, and utility among the merits of existing backhouses and it's product showed. The new designed model is considered to conveniences in modern toilet and staff is used instead to water as it is suitable for additional material of night-soil. This product was established at farm house and it's utility was proved. And a farmer easily are able to make this backhouse according it's design drawing.

• 한국농공학회논문집
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• 제46권1호
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• pp.35-40
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• 2004

This study is performed to examine the physical and mechanical properties of eco-concrete using soil, natural coarse aggregate, excellent soil compound and polypropylene fiber. The test result shows that mass loss ratio is decreased with increasing the content of coarse aggregate and excellent soil compound. The compressive and flexural strengths are increased with increasing the content of coarse aggregate, excellent soil compound and polypropylene fiber. The coefficient of permeability is decreased with increasing the content of coarse aggregate and excellent soil compound, but it is increased in 0.2% polypropylene fiber content. The lowest coefficient of permeability is showed in $5.066\times 10^{-9}$cm/s. These eco-concrete can be used for farm road.

• 한국농공학회논문집
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• 제52권6호
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• pp.111-123
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• 2010

In this study, laboratory model test on utilization of recycled aggregates and crushed stone as horizontal drains to use alternative material of sand in soft ground is practiced. The coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~5.1 times and 2.0~3.3 times greater than sand, respectively. The horizontal coefficient of permeability in case of installing the horizontal perforated drain pipe showed largely 1.9~6.8 times more than the case of not installing. The drainage distance showed 1.7~1.8 times greater than sand. When a degree of consolidation is 90 %, there is no delay of consolidation in SCP and PVD improvement sections. Therefore, it is proven that the field applicability is excellent. Also, the suitable quality management criterion is presented to make use of a horizontal drains in soft ground on the basis of analysis of the physical and environmental characteristics.