• Resources Recycling
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• v.29 no.1
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• pp.35-42
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• 2020

Even asbestos-containing waste (ACW) are highly harmful to humans, it continues being produced due to the massive disposal of asbestos-containing products. A development of asbestos detoxification and recycling technologies is required. Heat treatment using microwave is the most efficient method for ACW detoxification. However, microwave heat treatment method has the limitation that asbestos does not absorb microwave at room temperature. That is why, in this study, ACW was detoxified by microwave heat treatment adding the ACW between SiC plates, which are inorganic heating elements that absorb microwaves at room temperature. In order to improove the heat transfer, ACW was crushed and pulverized and then heated using microwave. Microwave heat treatment temperature and time variables were adjusted to investigate the detoxification properties according to heat treatment conditions. After heat treatment, treated ACW was analyzed for detoxification properties through crystal structure and microstructure analysis using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microwave heat treatment method using SiC plate can be heated up to the target temperature within a short time. Finally, complete asbestos detoxification was confirmed from the crystal structure and the microstructure when the microwave heat treatment was performed at 1,200℃ for at over 60 minutes and at 1,300℃ for at over 10 minutes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.382-386
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• 1983

In order to utilize effectively sea mustard(Undaria pinnatifida) which is excellent in nutrition and medical action, powdered sea mustard juice was prepared and then its chemical composition and the stability of pigments were examined. Powdered sea mustard was made by washing fresh sea mustard with tap water to remove clay and sand, blanching at $85^{\circ}C$ for 20 sec in mixing solution(3% salt+1% $MgCO_3$), hot air drying($50-55^{\circ}C$, 3 hrs) after draining and pulverizing dried sea mustard to 200mesh. And then powdered sea mustard mixtures for juice type beverage was made by adding 0.75% of salt, 1.25% of sugar, 0.2% of ascorbic acid, 0.25% of flour of roasted barley and 0.8% of pulverized sea mustard to 100ml of water. Chemical composition of product was not scarcely changed during processing while amino-nitrogen content was increased and alginic acid and ash contents were decreased. The retention of chlorophyll and total carotenoid pigments of product against fresh sea mustard were 91.6% and 89.5% respectively. Judging from sensory evaluation, color, flavor, taste and dispersibility of powdered sea mustard juice were excellent and undesirable flavor of product was masked by addition of flour of roasted barley.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.901-908
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• 2018

Graphite is used as a sample anode active material. However, since the maximum theoretical capacity is limited to $372mA\;h\;g^{-1}$, a new anode active material is required for the development of a high capacity lithium ion battery. The maximum theoretical capacity of Si is $4200mA\;h\;g^{-1}$, which is higher than that of graphite. However, it is not suitable for direct application to the anode active material because it has a volume expansion of 400%. In order to minimize the decrease of the discharge capacity due to the volume expansion, the Si was pulverized by the dry method to reduce the mechanical stress and the volume change of the reaction phase, and the change of the volume was suppressed by coating the carbon layers to the particle size controlled Si particles. And carbon fiber is grown like a thread on the particle surface to control secondary volume expansion and improve electrical conductivity. The physical and chemical properties of the materials were measured by XRD, SEM and TEM, and their electrochemical properties were evaluated. In this study, we have investigated the synthesis method that can be used as anode active material by improving cycle characteristics of Si.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.3
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• pp.132-139
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• 2019

EPS (expanded polystyrene) is one of the most used building materials for insulation that is favored by its excellent heat insulation, economical efficiency and lightweight characteristics. However, EPS is vulnerable to the fire and producing large amount of toxic gases in case of fire. Therefore, ultra-lightweight geopolymer which can replace EPS is fabricated by using IGCC (integrated gasification combined cycle) fused slag and Si sludge as raw materials and the possibility of replacement on ultra-lightweight geopolymer for EPS as an insulation building material was evaluated in this study. Ultra-lightweight geopolymer can be fabricated with the pulverized IGCC fused slag having low carbon content and density, compressive strength, thermal conductivity were $0.064g/cm^3$, 0.04 MPa, and 0.072 W/mK, respectively. The thermal conductivity of ultra-lightweight geopolymer is 1.5~2.0 times higher than that of EPS suggested in the KS M 3808; however, the thermal conductivity value of geopolymer is meaningful and competitive to that of EPS in the market. Therefore, ultralightweight geopolymer can be applicable to the building material for thermal insulation purpose and have an enough possibility to replace EPS in the future because it is not only much safer than EPS in case of fire but also it can be fabricate by using waste materials from the industry.

• Resources Recycling
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• v.29 no.6
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• pp.3-14
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• 2020

This study aims to introduce and review on the recovery technologies of rare earth elements(REEs) from coal ash. Many researchers have been carried out by various beneficiation processes, such as particle size separation, magnetic separation, specific gravity, and flotation to recover rare earth elements from coal ash generated from Pulverized Coal(PC) boiler. Through the beneficiation process, it was confirmed that concentration of rare earth elements was much lower than the 4,700 ppm, and that additional enrichment treatment through wet process was needed for the products recovered after the beneficiation process. It was confirmed that the rare earth elements contained in coal ash were applied to the leaching process after pretreatment such as alkali-fusion to improve leaching efficiency. Although beneficiation and leaching methods have been studied, its optimum recovery technologies for rare earth elements not been confirmed up to now, research on the recovery of rare earth contained in coal ash is reported to continue. In case of Korea, the technology for the recovery of rare earth elements from coal ash and coal by-product could not been confirmed up to present. In these reasons, it is urgent to develop technologies such as beneficiation and leaching process continuously.

• Geomechanics and Engineering
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• v.24 no.2
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• pp.115-127
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• 2021

This paper investigates the effects of soaking on a lime stabilized high plasticity clay and evaluates the implications for pavement design. In this context, the soil was stabilized by 4%, 6% and 9% hydrated lime. The soil was pulverized in two different gradations so that representative field gradations could be simulated. Both soil pulverization levels passed the relevant field gradation criteria. Curing durations were chosen as 7 days, 28 days and 56 days. Two groups of samples were prepared and were tested in unconfined compression test apparatus to measure the strength and secant modulus at failure values. One of the groups was tested immediately after curing. The other group of samples were first cured and then subjected to soaking for ten days before testing. Visual observations were made on the samples during the soaking period. The results showed the superiority of fine soil pulverization over coarse soil pulverization for unsoaked conditions in terms of strength and modulus values. Soaking of the samples affected the unconfined compressive strength and modulus values based on lime content, curing duration and soil pulverization level. In soaked samples, fine soil pulverization resulted in higher strength and modulus values compared to coarse soil pulverization. However, even with fine soil pulverization, effects of soaking on modulus values were more significant. A new term named as "Soaking Influence Factor (SIF)" was defined to compare the reduction in strength and modulus due to soaking. The data was compared with the relevant design guidelines and an attempt was made to include Soaking Influence Factors for strength and modulus (SIFS and SIFM) into pavement design processes. Two equations which correlated secant modulus at failure to unconfined compressive strength were proposed based on the samples subjected to soaking. The results of this study showed that in order to decrease the diverse effects of soaking for lime stabilized soils, soil pulverization level should be kept as fine as possible in the field. Importance of proper drainage precautions in the pavements is highlighted for better performance of the pavements.

• Clean Technology
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• v.26 no.4
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• pp.239-250
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• 2020

Biomass is an abundant renewable energy resource that can replace fossil fuels for the reduction of greenhouse gas (GHG). Indonesia has a large number of cheap biomass feedstocks, such as reforestation (waste wood) and palm residues (empty fruit bunch or EFB). In general, raw biomass contains more than 20% moisture and lacks calorific value, energy density, grindability, and combustion efficiency. Those properties are not acceptable fuel attributes as the conditions currently stand. Recently, torrefaction facilities, especially in European countries, have been built to upgrade raw biomass to solid fuel with high quality. In Korea, there is no significant market for torrefied solid fuel (co-firing) made of biomass residues, and only the wood pellet market presently thrives (~ 2 million ton yr-1). However, increasing demand for an upgraded solid fuel exists. In Indonesia, torrefied woody residues as co-firing fuel are economically feasible under the governmental promotion of renewable energy such as in feed-in-tariff (FIT). EFB, one of the chief palm residues, could replace coal in cement kiln when the emission trading system (ETS) and clean development mechanism (CDM) system are implemented. However, technical issues such as slagging (alkali metal) and corrosion (chlorine) should be addressed to utilize torrefied EFB at a pulverized coal boiler.

• Resources Recycling
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• v.30 no.4
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• pp.35-45
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• 2021

The humidity-control function and manufacturing characteristics of wood-wool boards using waste-paper-mulberry fiber were analyzed in this study. For the manufacture of wood-wool boards, the pulverizing times of waste-paper-mulberry fibers were controlled at 30, 60, 120, and 180 s, and the mixing amounts were controlled by adding 0%, 3%, 6%, and 9%, respectively, as compared to cement. Analysis of the moisture adsorption and desorption characteristics of the wood-wool boards controlled for pulverizing time revealed that the wood-wool board with 60 s of pulverized fiber exhibited the best adsorption and desorption performances. It was estimated that the adsorption and desorption performances of the material itself were adequate even when the boards were mixed because of minimal damage to the fiber. In addition, an analysis of the absorption and desorption characteristics of the fiber-mixture-controlled wood-wool boards showed that the 6%-mixed wood-wool board had the best absorption and desorption performances of 291.00 g/m² and 108.75 g/m², respectively.

• Korean Journal of Organic Agriculture
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• v.29 no.3
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• pp.415-427
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• 2021

It is generally recognized that high stocking density can increase the risk of immune dysfunction and reduction in productivity cause of elevated stress in broiler farm. The domestic livestock industry is implementing a certification system for animal welfare and livestock farms to reduce the problem of dense breeding. This study compared broiler from the general farm and animal welfare farm to confirm the effectiveness of animal welfare farms against stress. Gas concentrations in a farm of general and animal welfare farms were analyzed, blood (n=10) of the 28-day-old broiler was collected, the partial pressure of the gas in the blood was analyzed using whole blood, and biochemical factors and hormones were analyzed using the serum. Glycogen and L-lactate are analyzed using ELISA kit on finely pulverized muscles (n=10). CO₂ and NH₃ levels in the farm were significantly higher in general farm. Partial carbon dioxide tension (PCO₂) in blood was significantly higher and partial oxygen tension (PO₂) was significantly lower in the general farm. Creatinine (CREA), glucose (GLU), aspartateaminotransferase (AST), and creatinekinase (CK) in the blood were significantly higher in the general farm, and total protein (TP) and globulin (GLOB) were significantly higher in animal welfare farm. Blood corticosterone and norepinephrine were significantly higher in general farm and epinephrine was significantly higher in animal welfare farm. These results imply that animal welfare farm provides a stress-reduced breeding environment.

• Journal of Naturopathy
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• v.12 no.1
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• pp.7-15
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• 2023

Background: As a result of analyzing the components of wild Conyza canadensis, it contains physiologically active ingredients, so it is necessary to identify the compound. Purposes: It was to study the compound's molecular structure; a previous study showed that C. canadensis contains antioxidant substances. Methods: The ultrasonic pulverized lysate of C. canadensis stem and leaves was first extracted with 90% methanol and then five organic solvents. Next, the extracts was fractionated by HPLC, LC/MS chromatography, and NMR analyzers identified the molecular structure. Results: 100 g of dry C. canadensis was sonicated in 90% methanol and concentrated under reduced pressure to 11.96 g of a crude extract. Then, this crude was extracted with five types of solvents to obtain 123.8 mg of n-hexane, 448.2 mg of dichloromethane, 1047.7 mg of ethyl acetate (EA), 2563.8 mg of butanol, and 7.04 g of water. The EA extracts were fractionated by LC-MS and then re-fractionated to obtain F1 to F20. Next, the F15 was further fractionated to obtain nine fine fractions. Finally, the F17 fraction was re-fractionated to obtain ten fine fractions. As a result of LC-MS and NMR spectrometer analysis of the F15-7, the structure of this compound was confirmed as 3,5-dicaffeoylquinic acid. As a result of examining the structures of the F17-4 and F17-5 fractions, Quercetin-3-o-β-galactose was identified. In addition, the form of the F17-10 was confirmed to be 1,3,4-tri-caffeoylquinic acid. Conclusions: This study demonstrated that C. canadensis contained phenolic antioxidants, and its utilization may be expected.