• Journal of Mushroom
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• v.18 no.3
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• pp.274-279
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• 2020

This study was conducted to investigate the characteristics of the medium used on the composting step, comparing the excavator agitator with the self-propelled turner. The temperature of the outdoor composting medium tended to increase rapidly after flipping in the turner. The late composting medium temperature was maintained at the excavator treatment area (farm practice), and the late composting effect progressed. During the field composting stage, various microorganisms such as Bacillus spp., Actinomycetes, fluorescent Pseudomonas spp., and filamentous fungi were distributed in the medium, and the density of aerobic bacteria involved in the decomposition of the medium was increased. Under high-temperature composting conditions, blue fungi, and mesophilic actinomycetes were inhibited or killed. Thermophilic actinomycetes, which play an important role in decomposing organic matter, showed higher densities than those observed in farm practices in the self-propelled turner process. The length of rice straw was slightly shorter when the self-propelled turner was used, and the water content did not show any significant difference between treatments. The a and b values tended to increase as the inverter was turned over. The CN ratio of the composting broth was lowered from 23.1 to 16.2 for the 5th turnover in the context of farming practices, and from 23.3 to 16.9 in the context of the self-propelled turner. The yield of each treatment was increased by 20% in 1 period, 28% in 2 periods, and 26% in 3 periods; the overall yield was 23%.

• Journal of Periodontal and Implant Science
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• v.32 no.3
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• pp.523-537
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• 2002

The present study was performed to evaluate the effect of tetracycline - HCl on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and $TiO_2blasted$ surface were used. Implant surface was rubbed with 5Omg/ml tetracycline - HCl solution for ${\frac}{1}{2}$ min., 1 min., $1{\frac}{1}{2}$ min., 2 min., and 3min. respectively in the test group and with no conditioning in the control group. Then, the specimens were processed for scanning electron microscopic observation. The following results were obtained. 1. In the pure titanium machined surfaces, the control specimen showed a more or less rough machined surface composed of alternating positive and negative lines corresponding to grooves and ridges. After treatment, machining line was more pronounced for the control specimens. but in general, test specimens were similar to control. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. subsequently, the acid-etching process crated the micro roughness, which thus was superimposed on the macro roughness. 3. In the SLA surfaces, irrespective of the application time of 50mg/ml tetracycline-HCl solution, in general, test specimens were similar to control. 4. In the $TiO_2blasted$ surfaces the control specimen showed the rough surface with small pits. The irregularity of the $TiO_2blasted$ surfaces with 50mg/ml tetracycline-HCl solution was lessened and the flattened areas were wider relative to the application time of tetracycline - HCl solution. In conclusion, pure titanium machined surfaces and SLA surfaces weren't changed irrespective of the application time of tetracycline-HCl solution. And the $TiO_2blasted$ surfaces conditioned with tetracycline - HCl solution began to be changed from $1{\frac}{1}{2}$ min. This results are expected to be applied to the regenerative procedures for peri-implantitis treatment.

• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.227-234
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• 2014

Purpose: The aim of this research was to develop and evaluate natural hydroxyapatite (HA) ceramics produced from the heat treatment of pig bones. Methods: The properties of natural HA ceramics produced from pig bones were assessed in two parts. Firstly, the raw materials were characterized. A temperature of $1,200^{\circ}C$ was chosen as the calcination temperature. Fine bone powders (BPs) were produced via calcinations and a milling process. Sintered BPs were then characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, and a 2-year in vitro degradability test. Secondly, an indirect cytotoxicity test was conducted on human osteoblast-like cells, MG63, treated with the BPs. Results: The average particle size of the BPs was $20{\pm}5{\mu}m$. FE-SEM showed a non-uniform distribution of the particle size. The phase obtained from XRD analysis confirmed the structure of HA. Elemental analysis using XRF detected phosphorus (P) and calcium (Ca) with the Ca/P ratio of 1.6. Functional groups examined by FTIR detected phosphate ($PO{_4}^{3-}$), hydroxyl ($OH^-$), and carbonate ($CO{_3}^{2-}$). The EDX, XRF, and FTIR analysis of BPs indicated the absence of organic compounds, which were completely removed after annealing at $1,200^{\circ}C$. The BPs were mostly stable in a simulated body fluid (SBF) solution for 2 years. An indirect cytotoxicity test on natural HA ceramics showed no threat to the cells. Conclusions: In conclusion, the sintering temperature of $1,200^{\circ}C$ affected the microstructure, phase, and biological characteristics of natural HA ceramics consisting of calcium phosphate. The Ca-P-based natural ceramics are bioactive materials with good biocompatibility; our results indicate that the prepared HA ceramics have great potential for agricultural and biological applications.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.3
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• pp.34-39
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• 2015

Fluorescent whitening agents (FWAs) are widely applied in the papermaking process to improve the CIE whiteness and the ISO brightness of papers. Large amounts of FWAs are used in the paper and paperboard industry, but no standard method exists for quantitative FWA analysis. Therefore, a new method is needed to analyze the presence of FWAs in paper and paperboard to control their additions and applications. In particular, FWA analysis must concentrate on those used for surface treatment of paper because their use in surface applications has increased recently. The purposes of this study were to measure the optical properties of papers surface-treated with oxidized starch containing FWAs and to deduce the regression equations for the quantitative analysis of FWAs used for surface treatments. Surface sizing was carried out to treat the surface of a base paper with T-FWA and H-FWA, and the pickup weight of the surface sized paper was measured to determine the real weight of FWAs transferred onto the paper surface. After surface sizing and preconditioning, the paper was evaluated for CIE whiteness, ISO brightness, fluorescence index, and reflectance at 440 nm using an Elrepho spectrophotometer. The CIE whiteness and the ISO brightness increased linearly as FWA content increased. The fluorescence index and the reflectance showed linear relationships with T-FWA and H-FWA. Linear regression equations were determined for the quantitative analysis of FWAs used for surface treatments.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.526-532
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• 2008

The proposed $CO_2$ storage technology in the present study is a one-step sequestration process that stabilizes $CO_2$ in a reactor with Serpentine. The advantage of this technology is associated with its high stability of final product so that the entire system is recognized as permanent environment-friendly $CO_2$ removal method. Since the sequestration reaction mechanisms are generally understood that carbonation reaction proceeds with very slow rate, so that pretreatment method to increases reaction rate of $CO_2$ carbonation reaction should be developed. To increase the reactivity of Serpentine with $CO_2$, two different methods of pretreatment are carried out in the present investigation. One is heat-treatment, the other is chemical pretreatment. In this study, only chemical pretreatment is considered leaching method of magnesium from Serpentine using sulfuric acid at the various reaction temperatures, times, and acid concentrations. Experimental results illustrated that pretreatment by sulfuric acid increases surface area of serpentine from $11.1209m^2/g$ to $98.7903m^2/g$ and extracts magnesium compounds. Single variable experiment demonstrated the enhancements of magnesium extraction with increased reaction temperature and time. Amount of magnesium extraction is obtained by using the data of ICP-AES as maximum extraction condition of magnesium is 2 M acid solution, $75^{\circ}C$ and 1hr. After performing chemical pretreatment, carbonation yield increased from 23.24% to 46.30% of weight.

• Economic and Environmental Geology
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• v.46 no.6
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• pp.535-544
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• 2013

Influence of sulfate on the early hydration in the solidification treatment of abandoned mine tailings was characterized. Solidified specimens using hydrated lime as a binder were prepared with various amounts of added $Na_2SO_4$ and different curing days. Unconfined compressive strength measurement, heavy metal leaching test, XRD analysis were performed after 7-, 14- and 28-days curing. According to curing days strength of solidified specimens using only distilled water increased but those with addition of $Na_2SO_4$ decreased. External cracks of specimens developed definitely with increasing $Na_2SO_4$ concentration and curing days. Concentrations of Cu, Cd, Zn, and As in the leached solutions from solidified specimens decreased significantly but Pb was leached readily in cases of hydrated lime dosage more than 10 wt%. Gypsum and $MgSO_4$ were identified in the cracked solidified specimens by XRD analysis, and pillar-shaped crystals of SEM image were identified as gypsum in reference with EDS analysis. Crystallization of sulfate in the process of lime-tailing solidification caused cracking, which should be supplemented for solidification treatment of highly sulfur-contained tailing.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.902-911
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• 2010

Oriental melon ($Cucumis$ $melo$ var. $makuwa$) is a popular and high-value market fruit cultivated in Korea. Consumers are becoming increasingly interested in oriental melon as a healthy diet over the past few years. However, the melons have relatively high quality loss because the fruit are mainly produced for a limited period of time in the summer season. Lack of the proper postharvest treatments and high temperature exposure at harvest or during distribution are the most critical environmental factors limiting postharvest life of fruit. This review focuses on the overview of current research studies for postharvest treatment and functional packaging technology of oriental melon in Korea. Major physiological problems of the harvest fruit include the ripening process in quality changes of the produce such as loss of weight, firmness, flavor, and decay during the storage periods. Low temperature at 7 to $10^{\circ}C$ with high relative humidity of 90 to 95% is the suitable environmental condition used to maintain the quality of fresh oriental melon. Controlled atmosphere (CA) storage or modified atmosphere (MA) packaging can be used as supplemental treatments to extend postharvest-life. For oriental melon, an optimum CA is currently recommended to be 2-3% oxygen and 5-10% carbon dioxide atmosphere. Precooling, pretreatments of ethylene action and functional packaging system can be applied to oriental melon after harvest in order to extend storage life. Major active packaging technologies are concerned with a selectively gas permeable film related to respiration of produce and the packaging applications of ethylene removal, antimicrobial, and antifogging substances to keep the effective freshness of fruit.

• Journal of Hydrogen and New Energy
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• v.9 no.1
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• pp.16-24
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• 1998

Recently Zr-based $AB_2$ type hydrogen absorbing alloy has received much attention as a negative electrode material for the Ni-MH batteries because of its high capacity. In this study $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy was chosen and the effects of heat treatment and a partial substitution of the Mo in Mn site on the various electrode properties were investigated. The alloys was prepared by arc melting (as-cast sample). Some of them were heat treated at $1,100^{\circ}C$ for 4 hours. After this they were differentiated by the different cooling rates of slow cooling and quenching. Various electrode characteristics such as activation process, high rate dischargeability and self discharge characteristic were investigated with the three types of electrodes. It was found that heat treated alloys resulted in an increase in plateau flatness of P-C isotherms however both discharge capacity and high rate capability were decreased. And the partial substitution of Mo for Mn in $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy improved the self-discharge characteristic without the loss of discharge capacity (300mAh/g).

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.258-265
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• 1992

A low loss optical waveguide of $P_{2}O_{5}-SiO_{2}$on Si substrate is produced by using the chemical vapour deposition method of $SiO_2$ thin films used in Si technology. Propagation loss of the waveguide layer was 1.65 dB/cm as produced and reduced down to 0.1 dB/cm after heat treatment at $1100^{\circ}C$. By using laser lithography and reactive ion etching method $P_{2}O_{5}-SiO_{2}$ waveguide was produced and subsequently annealed at $1100^{\circ}C$.As a result of this annealing the shape of the waveguide core was changed from rectangular to semi-circular form, and the propagation loss was reduced as down to 0.03 dB/cm at 0.6328$\mu$m and 0.04dB/cm at 1.53$\mu$m. We think that the mechanism of the reduction in propagation loss during the heat treatment is the following: 1) The hydrogen bonding in waveguide layer, which causes absorption loss, is dissociated and diffused out. 2) The roughness of the interface and the micro-structure of the waveguide layer is removed. 3) The irregularities in the cross-sectional shape of the waveguide which was induced during the lithographic process were disappeared by flowing of the waveguide core.

• Journal of Environmental Science International
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• v.29 no.11
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• pp.1055-1064
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• 2020

In this research, heavy metals and T-P removal characteristics of plated wastewater are derived using BPC(Break Point Chlorination) process. AA sedimentation pond outflow(Influence) was evaluated for the removal efficiency of heavy metal(Ni) and T-P at a reaction time of 25 minutes by NaOCl input volume(9, 11, 13 and 15 mL). In the case, the higher the NaOCl input volumes, the higher the ORP values were maintained and the higher the removal efficiency tended to be. On the other hand, T-P was judged to have a low relationship between the ORP value and the removal efficiency. In addition, the efficiency of removal heavy metals and T-P in the plated wastewater by injecting 10 mL, 15 mL, 20 mL and 25 mL NaOCl, increased as the amount of NaOCl injected increased, the amount of NaOH input for pH increased. It was found that suspended solid in effluence also increased. It was also observed that the color of the plating wastewater changed from yellowish green to green to charcoal gray to black as the amount of NaOCl injected increased. Treatment characteristics of the reaction time, the longer the reaction time with the substance to be treated after the input of NaOCl, the more the heavy metal removal efficiency tended to increase. Through XRF analysis of the sludge, the constituents in the sludge such as NaCNO, CNCl, Na₃PO₄, CrO₄, 2Na₂CrO₄ and 2NaNO₃ will be analyzed in detail, and the mechanisms of the reaction between the plated wastewater and the complex compound will be elucidated.