• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.569-573
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• 2016

Strengthened regulations for atmospheric emissions from ships have created a need for new and alternative power systems that offer low emissions and high energy efficiency. Recently, new types of propulsion power systems, such as fuel cell systems that use hydrogen as an energy source, have gained serious consideration in applications requiring emission control. The purpose of this work is to certify the availability of solid oxide fuel cell (SOFC) systems equipped with recycled steam reforming fuel processors, and to compare their performance with that of extra steam reforming systems. The results demonstrate that the recycled steam reforming system has a slightly lower cell voltage and higher energy efficiency than the extra steam reforming system.

• Economic and Environmental Geology
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• v.50 no.4
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• pp.257-266
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• 2017

Batch experiments were performed to develop the method for the pH reduction of recycled aggregate by using $scCO_2$ (supercritical $CO_2$), maintaining the pH of extraction water below 9.8. Three different aggregate types from a domestic company were used for the $scCO_2$-water-recycled aggregate reaction to investigate the low pH maintenance of aggregate during the reaction. Thirty five gram of recycled aggregate sample was mixed with 70 mL of distilled water in a Teflon beaker, which was fixed in a high pressurized stainless steel cell (150 mL of capacity). The inside of the cell was pressurized to 100 bar and each cell was located in an oven at $50^{\circ}C$ for 50 days and the pH and ion concentrations of water in the cell were measured at a different reaction time interval. The XRD and SEM-EDS analyses for the aggregate before and after the reaction were performed to identify the mineralogical change during the reaction. The extraction experiment for the aggregate was also conducted to investigate the pH change of extracted water by the $scCO_2$ treatment. The pH of the recycled aggregate without the $scCO_2$ treatment maintained over 12, but its pH dramatically decreased to below 7 after 1 hour reaction and maintained below 8 for 50 day reaction. Concentration of $Ca^{2+}$, $Si^{4+}$, $Mg^{2+}$ and $Na^+$ increased in water due to the $scCO_2$-water-recycled aggregate reaction and lots of secondary precipitates such as calcite, amorphous silicate, and hydroxide minerals were found by XRD and SEM-EDS analyses. The pH of extracted water from the recycled aggregates without the $scCO_2$ treatment maintained over 12, but the pH of extracted water with the $scCO_2$ treatment kept below 9 of pH for both of 50 day and 1 day treatment, suggesting that the recycled aggregate with the $scCO_2$ treatment can be reused in real construction sites.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.118-124
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• 2016

The purpose of this study is to analyze the rheology characteristics of insulating concrete for each type of insulation performance improvement material and utilize the result as preliminary data for optimal flow designing and pumping analysis. As a result, when lightweight aggregate was mixed, the yield stress decreased significantly, and in case of type 2, the combination of micro form cell admixture (MFA) and calcined diatomite powder (DM) showed the most ideal flow characteristics. In case of type 3, the combination of micro form cell admixture (MFA), calcined diatomite powder (DM) and lightweight aggregate (L) showed the best flow characteristics.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.376-380
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• 2007

Used polyurethane (PU) was chemically degraded by the treatment with flame retardants such as tris(1,3-chloro-2-propyl) phosphate (TCPP), triethyl phosphate (TEP), and trimethyl phosphate (TMP). Analysis of FT-IR and P-NMR showed that the degraded products (DEP) contained oligourethanes. Rigid polyurethane foam was produced using the DEP as flame retardants. The flammability and thermal stability of recycled rigid polyurethane were investigated. The mechanical properties such as compressive strength of recycled polyurethane were also studied. The recycled polyurethane reduced flammability and enhanced thermal stability over intrinsic polyurethane. Mechanical strength of recycled polyurethane also shows as high as that of intrinsic polyurethane. In order to evaluate flame retardant properties of the recycled polyurethane foams with various amounts of DEP, heat release rate (HRR) of the foam was measured by cone calorimeter. Scanning electron micrograph of recycled PU showed a uniform cell morphology as a intrinsic PU.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1199-1208
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• 2005

Abatement of greenhouse gas emitted from ruminants and promotion of biogas energy from animal effluent were comprehensively examined in each anaerobic fermentation reactor and animal experiments. Moreover, the energy conversion efficiency of biomass energy to power generation were evaluated with a gas engine generator or proton exchange membrane fuel cell (PEMFC). To mitigate safely rumen methanogenesis with nutritional manipulation the suppressing effects of some strains of lactic acid bacteria and yeast, bacteriocin, $\beta$1-4 galactooligosaccharide, plant extracts (Yucca schidigera and Quillaja saponarea), L-cysteine and/or nitrate on rumen methane emission were compared with antibiotics. For in vitro trials, cumulative methane production was evaluated using the continuous fermented gas qualification system inoculated with the strained rumen fluid from rumen fistulated Holstein cows. For in vivo, four sequential ventilated head cages equipped with a fully automated gas analyzing system were used to examine the manipulating effects of $\beta$1-4 galactooligosaccharide, lactic acid bacteria (Leuconostoc mesenteroides subsp. mesenteroides), yeast (Trichosporon serticeum), nisin and Yucca schidigera and/or nitrate on rumen methanogenesis. Furthermore, biogas energy recycled from animal effluent was evaluated with anaerobic bioreactors. Utilization of recycled energy as fuel for a co-generator and fuel cell was tested in the thermophilic biogas plant system. From the results of in vitro and in vivo trials, nitrate was shown to be a strong methane suppressor, although nitrate per se is hazardous. L-cysteine could remove this risk. $\beta$1-4 galactooligosaccharide, Candida kefyr, nisin, Yucca schidigera and Quillaja saponarea are thought to possibly control methanogenesis in the rumen. It is possible to simulate the available energy recycled through animal effluent from feed energy resources by making total energy balance sheets of the process from feed energy to recycled energy.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.309-314
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• 1995

Samples were collected from a commercial ethanol production plant to enumerate the bacterial contamination in each step of a starch based ethanol production process. Though the slurry of raw material used in the process carried bacteria with various colony morphology in the order of $10^4$ per ml, only the colonies of white and circular form survived and propagated through the processes to the order of $10^8$ per ml at the end of fermentation. Almost all of the bacterial isolates from the fermentation broth were lactic acid bacteria. Heterofermentative Lactobacillus fermentum and L. salivarius, and a facultatively heterofermentative L. casei were major bacteria of an ethanol fermentation. In a batch fermentation L. fermentum was more detrimental than L. casei to ethanol fermentation. In a cell-recycled fermentation, ethanol productivity of 5.72 g $I^{-1} h^{-1}$ was obtained when the culture was contaminated by L. fermentum, whilst that of the pure culture was 9.00 g $1^{-1} h^{-1}$. Similar effects were observed in a cell-recycled ethanol fermentation inoculated by fermentation broth collected from an industrial plant, which showed a bacterial contamination at the level of 10$^8$ cells per ml.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.6
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• pp.357-361
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• 2002

Continuous production of lactic acid from glucose by Lactobacillus rhamnosus with cell recycling using an acoustic cell settler was carried out. The performance of the system, such as the concentration of cell and product were compared with the control experiment without recycling. The acoustic settler showed cell separation efficiency of 67% during the continuous operation and the cell concentration in the fermentor with recycle exceeded that of the control by 29%. Com-pared with the control, tactic acid production was increased by 40%, while glucose consumption was only increased by 8%. The higher value of lactic acid production to substrate consumption (Yp/s, product yield coefficient) achieved by cell recycling is interpreted to indicate that the recycled cell mass consumes less substrate to produce the same amount of product than the control Within system environmental changes due to the longer mean cell residence time induced the cells maintaining the metabolic pathways to produce Less by-Product but more product, lactic acid.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.291-296
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• 2010

Recently, recycling method of waste wafer has been an area of solar cell to cut costs. Micro_blasting is one of the promising candidates for recycling of waste wafer due to their extremely simple and cost-effective process. In this paper, we attempt to explore the effect of micro_blasting and DRE(damage removal etching) process for solar cell. The optimal process conditions of micro_blasting are as follows: $10{\mu}m$ sized $Al_2O_3$ powder, jetting pressure of 400 kPa, and scan_speed of 30 cm/s. And the particles formed on micro_blasted wafer were removed by DRE precess which was performed by using HNA(HF/$HNO_3$/$CH_3COOH$) and TMAH(tetramethyl ammonium hydroxide). Structural analysis was done using a-step and the XRD patterns.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.307-313
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• 2022

In this study, the correlation between Half Cell Potential(HCP) and the corrosion influencing factors was analyzed with considering three levels of water-cement ratio, the concentration of chloride solution, and cover depth. As a result of long-term corrosion monitoring, HCP behavior was close to the critical corrosion potential(-350 mV) in all water-cement ratios in the case of 3.5 % and 7.0 % chloride concentration. Regarding the passed charge test in 548 curing days, the passed charge results were improved to 'Moderate' grade. Multiple regression analysis was performed to evaluate the correlation between corrosion influencing factors and HCP, and it was evaluated that the effects of influencing factors to HCP were in the order of chloride concentration, water-cement ratio, and cover depth. In the case of the relationship between HCP and the passed charge, the coefficient of determination showed a high level of 0.9, which yielded a close correlation between the passed charge and HCP.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.80-84
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• 1994

In order to induce the rapid alcohol fermentation through the increases of the cell density in a continuous alcohol fermentation of naked barley, the single-cultivation with S. cerevisiae IS-019(SCM, ordinary control), mixed-cultivation with Saccharomyces uvarum IS-026 having a flocculent ability and S. cerevisiae IS-019(MCM), and mash recirculation by single-cultivation of S. cerevisiae IS-019(MRM) modes were investigated. The cell mass in the mixed-cultivation mode was about 10% higher than that of ordinary control but the final alcohol yield was slightlyl decreased. When recycled the mash with the flow rate of 7 l/h from V$_{6}$ to V$_{5}$ fermentors under the ordinary control, the cell density was distributed at 140~170$\times $10$^{6}$ cell/ml depending upon the fermentorsorders, higher about 20% than that of the ordinary control. Under these conditions the alcohol productivity of the maximum and the overall was 12.16 g/l$\cdot $h with an alcohol of 7.6% at the V$_{5}$ fermentor and 1.19 g/l$\cdot $h with an alcohol of 8.94%, respectively. For higher cell mass it was more effective to apply the mash recirculation mode with the single-cultivation of S. cerevisiae IS-019 in a pilot scale multi-stage CSTR.