• Journal of Hydrogen and New Energy
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• v.27 no.1
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• pp.13-21
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• 2016

The Sulfur-Iodine thermochemical hydrogen production process (SI process) consists of the Bunsen reaction section, the $H_2SO_4$ decomposition section, and the HI decomposition section. The $HI_x$ solution ($I_2-HI-H_2O$) could be recycled to Bunsen reaction section from the HI decomposition section in the operation of the integrated SI process. The phase separation characteristic of the Bunsen reaction using the $HI_x$ solution was similar to that of $I_2-H_2O-SO_2$ system. On the other hands, the amount of produced $H_2SO_4$ phase was small. To investigate the effects of $SO_2$ solubility on Bunsen reaction, the continuous Bunsen reaction was performed at variation of the amounts of $SO_2$ gas. Also, it was carried out to make sure of the effects of partial pressure of $SO_2$ in the condition of 3bar of $SO_2-O_2$ atmosphere. As the results, the characteristic of Bunsen reaction was improved with increasing the amounts and solubility of $SO_2$ gas. The concentration of Bunsen products was changed by reverse Bunsen reaction and evaporation of HI after 12 h.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.251-256
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• 2013

Multiwalled carbon nanotubes (MWCNTs) modified with Pd and $TiO_2$ composite catalysts were synthesized by the sol-gel method followed by solvothermal treatment at low temperature. The chemical composition and surface structure were characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Photocatalytic recycle degradation experiments were carried out under both UV and visible light irradiation in the presence of MWCNT/$TiO_2$ and Pd-MWCNT/$TiO_2$ composites. As expected, the nanosized Pd-MWCNT/$TiO_2$ photocatalysts had enhanced activity over the non Pd treated MWCNT/$TiO_2$ material in the degradation of a rhodamine B (Rh.B) solution. An increase in photocatalytic activity was observed and attributed to an increase in the photo-absorption effect by MWCNTs and the cooperative effect of Pd and $TiO_2$ nanoparticles. According to the recycled results, the as-prepared Pd-MWCNT/$TiO_2$ sample had a good effect on it.

• Molecules and Cells
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• v.37 no.3
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• pp.257-263
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• 2014

A mammalian cell renovates itself by autophagy, a process through which cellular components are recycled to produce energy and maintain homeostasis. Recently, the abundance of gap junction proteins was shown to be regulated by autophagy during starvation conditions, suggesting that transmembrane proteins are also regulated by autophagy. Transient receptor potential vanilloid type 1 (TRPV1), an ion channel localized to the plasma membrane and endoplasmic reticulum (ER), is a sensory transducer that is activated by a wide variety of exogenous and endogenous physical and chemical stimuli. Intriguingly, the abundance of cellular TRPV1 can change dynamically under pathological conditions. However, the mechanisms by which the protein levels of TRPV1 are regulated have not yet been explored. Therefore, we investigated the mechanisms of TRPV1 recycling using HeLa cells constitutively expressing TRPV1. Endogenous TRPV1 was degraded in starvation conditions; this degradation was blocked by chloroquine (CLQ), 3MA, or downregulation of Atg7. Interestingly, a glucocorticoid (cortisol) was capable of inducing autophagy in HeLa cells. Cortisol increased cellular conversion of LC3-I to LC-3II, leading autophagy and resulting in TRPV1 degradation, which was similarly inhibited by treatment with CLQ, 3MA, or downregulation of Atg7. Furthermore, cortisol treatment induced the colocalization of GFP-LC3 with endogenous TRPV1. Cumulatively, these observations provide evidence that degradation of TRPV1 is mediated by autophagy, and that this pathway can be enhanced by cortisol.

• Journal of Apiculture
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• v.34 no.4
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• pp.315-323
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• 2019

Large amounts of sludge produced by paper mill industries represent one of the most serious environmental problems in the world. Recently, beekeepers living in the neighborhood of the paper mill in Hwasan County, Youngcheon city, GB, Korea, became alarmed that honey bee colonies were dying off suddenly across the neighborhood. A preliminary study was conducted to evaluate the toxicity (oral, fumigation, repellent) of recycled solid paper mill sludge (SPMS) and leachate paper mill sludge (LPMS) to honey bee workers under laboratory conditions, and to analyze the volatile organic compounds(VOC). The SPMS and LPMS were separately subjected to a liquid-liquid extraction (LLE) at three temperatures to extract VOC(highest VOC yields: 1.52% SPMS and 0.34% LPMS). A total of 70 chemicals were detected in the VOC of paper mill sludges, of which 49 and 21 volatile organic compounds from SPMS and LPMS, respectively. The SPMS was dominated by high degree presence of stanols (saturated sterols), such as cholestanol, cholestan-3-ol and also saturated hydrocarbons. However, LPMS was characterized by the absence of sterols. Both SPMS and LPMS showed an influence on the olfactory behavior of honey bee on Y-tube assay, with repulsion rates of 72 and 68%, respectively. Both SPMS and LPMS at concentration of 100mg/mL caused higher honey bee oral mortality than the untreated controls at 48, 72, 96 and 120 hours after treatment(highest oral mortality at 120 hr: 85.74%(SPMS); 93.51 % (LPMS)). A similar pattern was observed when honey bees were tested to fumigant toxicity. Both SPMS and LPMS caused significant higher mortality than the untreated control 24 hour after the exposure (highest fumigation mortality at 120 hr: 69.4% (SPMS); 56.8% (LPMS)). These preliminary results indicated that paper mill sludge could be partly responsible for sudden death and disappearance of honey bees, especially in hot humid summer days. With climate change, the risk of environmental chemical exposure to honey bee would pose greater attention.

• Resources Recycling
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• v.30 no.4
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• pp.46-53
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• 2021

Biomass can be considered as chemical energy obtained from nature, and includes all living organisms such as plants, animals, and microorganisms. Biomass is eco-friendly, is easily obtainable from the environment, and can be recycled without special treatment processes. Biomass can also be converted into bioenergy fuel through pyrolysis and fermentation. Therefore, it has been considered as a renewable energy source, which prevents the depletion of natural resources such as fossil fuels. In this study, torrefaction to increase the carbon content in various types of biomass sources (sawdust, rice straw, rice bristles, coffee ground, and waste wood) was conducted under an inert atmosphere and at a temperature of 523~573K. The possibility of using torrefied biomass as an alternative to solid fuel for industrial purposes was analyzed by examining the carbon concentration and combustion behaviors.

• Journal of Life Science
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• v.33 no.1
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• pp.82-90
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• 2023

Biological process is used worldwide to treat domestic and industrial wastewater. The process generally uses a mixed microbial culture of sludge. The growth of microorganisms in the sludge produces excess sludge from the wastewater treatment process. Some of the excess sludge is recycled as inoculum for wastewater treatment, but the rest is removed as waste from the process. As wastewater production is increasing worldwide every year, the number of wastewater treatment plants (WWTPs) is also in- creasing, resulting in the generation of large amount of waste sludge. The increasing amount of waste sludge from WWTPs has led to concerns about its management. Sludge disposal has been reported to account for 50~60% of the total operating costs of a WWTP. Sludge disintegration is a new technology that can minimize volume of waste sludge and recover useful components (e.g., P, N, and soluble organic compounds) from it. Various methods of sludge disintegration have been developed based on physical, chemical, and biological treatments or combinations of these. In this review, we focus on sludge disintegration by acid hydrolysis, which is less studied among sludge disintegration methods. Such information can be useful in the development and implementation of a new technology for better sludge treatment.

• Advances in concrete construction
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• v.16 no.6
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• pp.291-302
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• 2023

As the first part of the body that strikes the ground during running, sports shoes are especially important for improving performance and reducing injuries. The use of new nanotechnology materials in the shoe's sole that can affect the movement angle of the foot and the ground reaction forces during running has not been reported yet. It is important to consider the material of the sole of the shoe since it determines the long-term performance of sports shoes, including their comfort while walking, running, and jumping. Running performance can be improved by polymer foam that provides good support with low energy dissipation (low energy dissipation). Running shoes have a midsole made of ethylene propylene copolymer (EPP) foam. The mechanical properties of EPP foam are, however, low. To improve the mechanical performance of EPP, conventional mineral fillers are commonly used, but these fillers sacrifice energy return. In this study, to improve the magnificence of physical education training with nanotechnology, carbon nanotubes (CNTs) derived from recycled plastics were prepared by catalytic chemical vapor deposition and used as nucleating and reinforcing agents. As a result of the results, the physical, mechanical, and dynamic response properties of EPP foam combined with CNT and zinc oxide nanoparticles were significantly improved. When CNT was added to the nanocomposites with a weight percentage of less than 0.5 wt%, the wear resistance, physical properties, dynamic stiffness, compressive strength, and rebound properties of EPP foams were significantly improved.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.203-212
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• 2005

Cellulose insulation is primarily manufactured from recycled newsprint and treated with fire retardants for the fire resistance. Thanks to the fire retardants, it is not combustible and flammable. In addition to that, Its thermal resistance is much better than that of fiberglass or rock wool. It is made from waste paper and easily decayed when it is demolished, and it has small embodied energy. So it is very environment-friendly building material. For broader use of cellulose insulation in buildings in Korea, it is necessary to test its physical performance to compare the results with the requirements on the Korean Building Code. To this end, apparent thermal conductivity (ka) measurements of Korean-made loose-fill cellulose insulations were recently completed using equipment that was built and operated in accordance with ASTM C 518 and the fire resistance was tested in accordance with ASTM C 1485. Korean loose-fill cellulose has thermal conductivity about 5% greater than the corresponding U.S. product at the same density. This is likely due to differences in the recycled material being used. Both spray-applied and loose-fill cellulose insulation lose about 1.5% of their thermal resistivity for $5.5^{\circ}C$ increase in temperature. The fire resistance of cellulose insulation is increased in linear proportion to the increase of the rate of fire retardant. Thanks to the high fire resistance, cellulose insulation can be used as a substitution of Styrofoam or Urethane foam which is combustible. The thermal conductivity of cellulose insulation was $0.037-0.043W/m{\cdot}K$ at the mean specimen temperature from $4-43^{\circ}C$. It corresponds to the thermal resistance of "Na Grade" according to the Korean Building Code. The effect of chemical content on thermal conductivity was negligible for all but the chemical-free specimen which had the highest value for the thermal conductivity over the temperature range tested. The thermal resistance of cellulose insulation is better than that of fiberglass or rock wool, and its fire resistance is higher than that of Styrofoam or Urethane foam. Therefore it can be substituted for those above considering its physical performance. Cellulose insulation is no more expensive than Styrofoam or rock wool, so it is recommended to use it more widely in Korea.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.143-151
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• 2004

This study focused on examining the possibility of recycling mine solid waste as environmental materials, especially for porous media. Basic properties including mineralogical compositions, chemical compositions, and particle size distribution of the tailings from the Sangdong W mine were checked. The mineralogical and chemical compositions of the tailings samples were not much different in depth. According to Korean Standard Leaching Test for Wastes(KSLT), concentrations of heavy metals leached from the tailings were below the standard values. As a result of particle size analysis, the median diameter (d$_{50}$) of the tailings was in the range of 10 to 30 ${\mu}{\textrm}{m}$. The stable tailings slurry made up of 3 ${\mu}{\textrm}{m}$ in d$_{50}$ was prepared using Attrition Mill. The milling condition was 40 vol% in slurry concentration, 700 rpm in stirring speed, and 1 hour in milling time. PEI was added as dispersing agent. Concentrated slurry was extended to 3 times by foaming method. In the case of 3 times foamed slurry, the total and open porosity of ceramic supports sintered at 1,075$^{\circ}C$ for 90 minutes was about 80% and 72%, respectively. Pore size was in the range of 30∼350${\mu}{\textrm}{m}$. Therefore, the tailings could be recycled starting material for environmental materials such as macroporous ceramic support.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.42-45
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• 2008

It has been reported that FRP (fiber reinforced plastic) can be recycled by separating into layers instead of crushing into powder. F-fiber obtained from roving layer separated from FRP, has bigger tensile strength than the bundle of glass fibers of which FRP was made (more than 90%). SEM image of F-fiber shows the presence of some resin. Under the proposition of usage of F-fiber in the concrete material, tensile strength is examined after soaking in a basic solution (NaOH+KOH). The reaction mechanism of strength loss may be considered as an attack of hydroxide ion ($OH^-$) on a chemical bond of Si-O-Si of glass fiber. The simulation graph of the strength loss data implies certain reaction mechanism. While in the early stage kinetically controlled reaction results in a fast drop of tensile strength, after 30 days dispersion rate of hydroxide ion plays a major role in strength loss. This result is similar to the one for the AR glass. An extrapolation of the graph would make an assumption about the lift time of F-fiber possible.