• Journal of Practical Agriculture & Fisheries Research
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• v.9 no.1
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• pp.33-46
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• 2007

We conducted this research to develop the medium for some edible mushroom cultivation using shiitake waste log which is abandoned after cultivation of shiitake mushroom because those bed logs can not be recycled. The isolates of P. ostreatus(POS-012), P. eryngii(PER-005), G. frondosa(GFR-001) and F. velutipes(FVE-001) were selected and examined for mycelial growth on sawdust media prepared from shiitake waste log. Mycelial growth of selected isolate were satisfactory on the sawdust extract media using acasia(Robinia pseudo-acacia), neutinamu(Zelkova serrata) and kangchamnamu(sangsuri, Quercus acutissima) which are no shiitake-inoculated. Although the mycelial growth of the isolate were poor on the sawdust media prepared from Quercus spp., sawdust of neutinamu, (Zelkova serrata), beotnamu, (Prunus serrulata), orinamu(Alnus japonica), eunsuweonsasinamu(Populus tomentiglandulosa) and chestnut(Castanea crenata) were excellent for mycelial growth. However, shiitake logs which are infected with harmful fungi such as Hypocrea spp. were useful as recycle materials for mushroom cultivation.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.57-68
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• 2023

In this study, coffee waste was recycled into nitrogen-doped porous carbon fibers as an active material for high-energy EDLC (Electric Double Layer Capacitors). The coffee waste was mixed with polyvinylpyrrolidone and dissolved into dimethylformamide. The mixture was then electrospun to fabricate coffee waste-derived nanofibers (Bare-CWNF), and carbonization process was followed under a nitrogen atmosphere at 900℃. Similar to Bare-CWNF, the as-synthesized carbonized coffee waste-derived nanofibers (Carbonized-CWNF) maintained its fibrous form while preserving the composition of nitrogen. The electrochemical performance was analyzed for carbonized coffee waste (Carbonized-CW)-, carbonized PAN-derived nanofibers (Carbonized-PNF)-, and Carbonized-CWNF-based electrodes in the operating voltage window of -1.0-0.0V, Among the electrodes, Carbonized-CWNF-based electrodes exhibited the highest specific capacitance of 123.8F g^-1 at 1A g^-1 owing to presence of nitrogen and porous structure. As a result, nitrogen-contained porous carbon fibers synthesized from coffee waste showed excellent electrochemical performance as electrodes for high-energy EDLC. The experimental designed in this study successfully demonstrated the recycling of the coffee waste, one of the plant-based biomass that causes the environmental pollution into high-energy materials, also, attaining the ecofriendliness.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.5-14
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• 2023

In this study, LiDAR-reflective black hollow-structured silica/titania(B-HST) materials are successfully synthesized by employing the NaBH₄ reduction and etching method on silica/titania core/shell(STCS) materials, which also effectively enhance near-infrared(NIR) reflectance. Moreover, core-etched supernatant solutions are collected and recycled for the synthesis of extracted silica(e-SiO₂) process, which successfully applies as filler materials for semiconductor epoxy molding compound(EMC). In detail, B-HST materials, fabricated by the sequential experimental steps of sol-gel, reduction, and sonication-mediated etching method, manifest blackness(L^*) of 13.2 similar to black paint and excellent NIR reflectance(31.1%). Consequently, B-HST materials are successfully prepared as LiDAR-reflective black materials. Additionally, core-etched supernatant solution with silanol precursors are employed for synthesis of homogeneous silica filler materials via sol-gel method. As-synthesized silica fillers are incorporated with epoxy resin and carbon black for the preparation of semiconductor EMC. Experimentally synthesized EMC exhibits comparable mechanical-chemical properties to commercial EMC. Conclusively, this study successfully proposes designing procedure and practical experimental method for simultaneously synthesizing the NIR-reflective black materials for self-driving vehicles and EMC materials for semiconductors, which are materials suitable for the industrial 4.0 era, and presented their applicability in future industries.

• Design Convergence Study
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• v.14 no.4
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• pp.119-132
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• 2015

The enforcement of volume-rate disposal system which has been resulted in reducing the household waste and increasing the amount of recycled contents is showing positive effects that are generating social and economic benefits, However due to the lack of user's perception about how to separate and dispose of recycling wastes, some problems are constantly raised, like food waste is disposed in the standard volume-rate garbage bag. By rearranging visual information printed on standard plastic garbage bags (SPGB), this study attempted to find ways to deliver the information regarding how to use them properly. In order to achieve this, from the perspective of visual information design, the study examined the cases of visual information printed on nine SPGB from domestic and overseas. Among these, this study conducted a survey on user's awareness of visual information printed on SPGB in three districts of Seoul, Korea. As a result, user-preferred items were identified. Based on the result, this study selected information to be printed on SPGB, established the hierarchical order of the selected information, and proposed a guideline for using SPGB with informative graphics; therefore, the effectiveness of information delivery was improved. In addition, this study also examined the external validity of the guideline by comparing a survey on user's awareness.

• Clean Technology
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• v.29 no.2
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• pp.102-108
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• 2023

This study applied a hydrothermal carbonization (HTC) method to carbonize sewage sludge in order to satisfy the criteria of the Waste Management Act for recycled products and to explore the possibility of recycling sludge into modification blocks. Cement was mixed with carbonized sludge generated at the optimal temperature and reaction time during HTC. After that, the compressive strengths of the modification blocks were measured by conducting both a performance and leaching test. The results of the leaching test showed that heavy metals were not detected, and the specific gravity and absorption rates were less than 1.7 and 10%, respectively, indicating that all species satisfied the criteria. The results of the compressive strength test showed that a mixing ratio of 5% and 7% with cement cured for 28 days satisfied the criteria of A, B, and C type blocks but a mixing ratio of 3% with cement did not satisfy the criteria of A type blocks after 28 days. However, after additional curing for 42 days, the mixing ratio of 3% also satisfied the A type block criteria. Therefore, the optimal mixing ratio of carbonized sludge and cement was considered to be between 3% and 5% and confirmed that the modified blocks could be utilized as aggregates.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.365-368
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• 2021

In this study, a plastic bottle recycling bin system that utilizes an infrared sensor was implemented. The proposed system consists of a recognition unit, a control unit, an alarm unit, and a driving unit. The recognition unit detects the plastic bottle, measures the distance between the plastic bottle and the infrared sensor, extracts the value of the bottle, compares the extracted value with a standard range, and then transmits the control value to the control unit if the extracted value of the bottle is outside the standard range. In this case, the result of the presence or absence of a brand label or bottle cap is transmitted to the controller. The control unit opens the entrance of the recycling bin or alerts the alarm unit according to the result value transmitted from the sensor unit. In order to implement the proposed system, the recognition unit was implemented with an infrared sensor, and the control unit was made with an Arduino IDE controller, based on the C programming language. Additionally, the recognition unit and the control unit are able to communicate using analog signals. The proposed system accurately judges the presence or absence of a brand label and bottle cap of plastic bottles according to a predetermined algorithm. It then blocks the entrance of the recycling bin when a brand label or bottle cap is still attached. As the amount of waste discharged per person is relatively high and the majority of such waste is incinerated rather than recycled, the system proposed in this study is expected to increase the recycling rate of plastic bottles.

• Korean Journal of Environmental Agriculture
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• v.41 no.4
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• pp.236-244
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• 2022

BACKGROUND: Liquid fertilizers can provide nutrients to crops effectively and quickly. Amino acid liquid fertilizers produced by decomposing the residues of rendered livestock carcasses are expected to be effective in improving the productivity and quality of crops. METHODS AND RESULTS: The treatment conditions for maize cultivation were control (Cn), inorganic fertilizer (IF), inorganic fertilizer and rendering residue liquid fertilizer (IF+RALF), compost (CP), compost and rendering residue liquid fertilizer (CP+RALF). Crop productivity, sugar content, and nutrient uptake were investigated after maize harvest in the field applied with liquid fertilizers. Maize yields ranged from 87.6-158 g/plant, and the yield increased by 7.9% and 12.9% in IF+RALF IF+RALF and CP+RALF than in IF and CP, respectively. The maize sugar content increased in the range of 0.1-0.5 brix % by rendering residue liquid fertilizer (RALF) fertilization, and the sugar content was the highest in CP+RALF. There was no significant change in soil chemical properties of the soil due to liquid fertilizer treatment. CONCLUSION(S): RALF increased yield and sugar content in maize cultivation, and fertilization with organic fertilizers was more effective for maize cultivation than inorganic fertilizers. Residues of rendered livestock carcass can be recycled as amino acid fertilizers, which can be effectively used for crop production and quality improvement.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.607-617
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• 2023

This study aims to analyze whether the performance of the fire extinguisher meets the criteria for the apparent specific gravity property test by calculating the change in internal pressure and the use period of the fire extinguisher as a new one with 5 years, recycled one with 5 years, a new one with 10 years, and a new one with 13 years, respectively. As a result of the experiment, when the internal pressure of the fire extinguisher was 0%, the first, second, and third arithmetic mean analysis of the dry chemical extinguisher according to the use period was found to be condemned. When the internal pressure of the fire extinguisher was 50%, it was measured as 130 ml in sample 12-08-new and analyzed as unsuitable. Also, sample 09-09-new of a new dry chemical extinguisher with 13 elapsed years measured 145ml, which was found inappropriate. All other dry chemical extinguishers were analyzed to be suitable. All were noted suitable when having normal internal pressure of the fire extinguisher, except for sample 09-06 of a new dry chemical extinguisher with 13 elapsed years, which was determined to be unsuitable caused by measuring as 131 ml for experimental value. As a result of experiments, some of the apparent specific gravity tests of dry chemical extinguishers from 10 years to 13 years have found that they are unsuitable for the performance of the fire extinguishers due to the massive phenomenon. Accordingly, it is necessary to reduce the endurance period of dry chemical extinguishers from 10 years to 7 years.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.77-84
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• 2023

As the installation of solar panel accelerates, so does the number of solar panels reaching their end-of-life (EOL). However, the EOL solar panels is becoming a concern, as they contain potentially hazardous materials and are not easily recycled. Coping strategies such as effective collection, disposal, and recycling methods will be important to manage the growing number of EOL solar panels in the coming years.Therefore, many studies have focused on the development of EOL solar panel recycling technology. One recycling technology for EOL solar panels applicable to the construction field is the application of extracted tempered glass from EOL solar panels as construction materials. This study summarized the EOL solar panel disassembly technology and evaluated the mechanical properties of mortar using extracted tempered glass as fine aggregate. The results showed that when tempered glass was used as a fine aggregate in mortar, the compressive strength, flexural strength, and macro pores in the 1-3 ㎛ with 200-300 ㎛ range were affected, regardless of the disassembly technology of EOL solar panels. Especially, we found that the mechanical performance of mortar using chemically treated tempered glass was noticeably decreased due to changes in the chemical composition of the extracted tempered glass resulting from the removal of K₂O and CuO due to chemical reactions. Meanwhile, it was found that when fly ash was used as a binder, the reduction of mechanical performance could be alleviated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3C
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• pp.159-165
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• 2010

The problems such as natural resource exhaustion, pollutant emission and waste generation are increasing worldwide with the industrial development. The quantity of the industrial by-product in Korea is 6 million tons a year, and even its basic treatment processes including landfill, incineration and storage have reached their limits. In this study, fly ash and silica fume were applied to shotcrete to develop a method for the reuse of resources and to increase the use of fly ash, which is an industrial waste. An environmental hazard evaluation is a must to actively address the worldwide environmental problems, though. Therefore, an environmental impact assessment was conducted using the chemical content analysis test and heavy metal exudation test, for ten mixtures that were obtained through the pre-mixing and compressive strength tests. The results of the compressive strength test showed that all mixtures satisfied national and international standards. Cr, Cd and Hg were not detected, and Pb was detected only in some cases with fly ash. Cu and As were detected in all mixtures, but all of them satisfied national and international standards.