• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.722-728
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• 2000

This study of field control machine in the recycled vinyl rail is gantry crane type and promoting agricultural automatization through self-controlled spraying, harvesting and conveyance. In addition to, that control machine could get a cost and labor reduction effect through automatization and make better environment by preventing farmers from agrichemical damage, accidents and recycling wasted vinyl. That machine is able to be divided as traveling, spraying, harvesting and conveyance sections. In driving section consists of girder frame, carrier, rail, control system, driving system, working machine, rail and loading device for working machine. This machine has following advantages to be able to bring a big innovation in the agricultural industry. I) Accurate performance is able to be done by proper positioning due to based on the rails. 2) The soil is not made hard like heavy tractor 3) The wheel is not sank into the soil and slipped well under rain like heavy tractor. Therefore, weather and soil situation could not affect working condition. 4) Complete unmanned control and 24hours-working are available due to traveling on the rails. 5) It could use various energy resources like not only liquid fuel but also solar, common electronic power due to traveling on the rails.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.2
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• pp.1-8
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• 2012

This study is carried out to find the most optimal soil-plant combination in the urban agriculture by analyzing the association of soil base material which is being used in the urban agriculture with the growth of plants. 4 types of easily purchased soil (bed soil(A), animal vermicast soil(B), earth worm soil(C) and matured compost(D)) verified in aspects of effect and safety of soil in terms of growth of crop is selected as experimental soil and B, C, D type soils are mixed with granite soil at the ratio of 7 : 3. And granite soil(E) is set as a controlled soil and is compared to verify the effect of the experimental mixed soil. Herbaceous plants are classified into the fruit vegetables (Lycopersicon esculentum Mill. and Capsicum annuum L.), leafy vegetables (Brassica campestris L. ssp. Pekinensis and Lactuca sativa L.), medicinal vegetables (Chrysanthemum zawadskii var. latilobum and Liriope platyphylla F. T. Wang & T. Tang). The results of comparison of growth of herbaceous plants in different soil types showed that fruit vegetables and leafy vegetables in general had excellent growth in D type soil mixture and A type soil in general and had the poorest growth in E type (controlled) soil. 'Chrysanthemum zawadskii var. latilobum' had the excellent growth in D type, B type, C type mixed soil and A type soil and E type (controlled) soil are followed in order. In the case of 'Liriope platyphylla F. T. Wang & T. Tang', the difference in growth by each soil was shown to be insignificant. Therefore, the soil applied in the urban agriculture varies depending on each species of herbaceous plants, but it is considered effective to cultivate herbaceous plant which is economical and productive by using D type mixed soil which can be recycled and inexpensive compared with other experimental soils in the urban agriculture.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.97-103
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• 2011

In this research, a small-scaled laboratory test and FEM analysis have been carried out to evaluate the feasibility of field construction with couple of recycled materials, such as in-situ soil, water-treatment sludge, and crumb rubbers. A static loading, which simulates the real traffic load, was adopted in lab test. The test was carried out, according to simulated field construction stages, such as excavation, bedding materials and pipe installation, placing and curing of controlled low strength materials, and simulated traffic loading. Couple of measuring instruments were adopted. The maximum vertical and horizontal deformations were 0.83% and 1.09%, during placing the CLSM. The measured vertical and horizontal deformations with curing time were 0.603mm and 0.676mm, respectively. The reduction effect of vertical and lateral earth pressure was relatively big. Also, FEM analysis was carried out to get the deformation, earth pressure and strain of PVC with different Controlled Low Strength Materials(CLSM) materials.

• Resources Recycling
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• v.17 no.6
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• pp.34-42
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• 2008

The properties of sodium silicate solution were surveyed by using the yellow silicomolybdic method, and the formation of silica sol from sodium silicate solution and the growth of silica sol were investigated in this study. The $SiO_2$ content of 2 wt% in sodium silicate solution was proper to oxidize sodium silicate with sulfuric acid. After the removal of sodium ions in sodium silicate solution, the pH of silicate solution had to be controlled above 9 for the stabilization of silicate solution. The condensation between silicic acid species and silica nuclei surfaces has been studied at $20{\sim}80^{\circ}C$ and pH 10 in silicate solutions with silica nuclei. The reaction falls into two kinetics regimes, limited at high silicic acid species concentration by polymerization, but at lower concentration by a process whereby deposited silicic acid species condenses further to silica. The overall condensation is first-order in silicic acid species concentration, proceeded toward to pseudo equilibrium concentration, $C_x$, rather than the solubility of amorphous silica. The heat of solution of amorphous silica was 3.34 kcal/mol and exhibits an Arrhenius temperature dependence with an apparent activation energy of 3.16 kcal/mol in the range of $20{\sim}80^{\circ}C$.

• International Journal of Highway Engineering
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• v.4 no.2 s.12
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• pp.19-31
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• 2002

The recycling of waste foundry sand(WFS) and fly ash as by-products of industry is one of the urgent problem to deal with. For the recycling of these materials, CLSM(controlled low strength materials) concept was adopted. This research has been done for last three years. In this research, couple of selected waste foundry sand and fly ash were used as fine aggregate. Also, WFS modified by Proper chemical liquid was used for the comparison. The main focus is to evaluate the silo earth pressure and the reduction effect due to the use of CLSM instead of normal fine aggregate. Silo effect, which occurs at short distance between retaining wall and backfill, was not detected because the characterization of CLSM is highly different from that of normal aggregate. Therefore, the theory for earth pressure, like Rankine theory or Coulomb theory, should be carefully used for CLSM. The reduction of earth pressure for modified WFS is higher than the others. But, the final earth pressure is converged at very small value, even though the reduction effect depends on the curing time.

• Resources Recycling
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• v.24 no.1
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• pp.35-42
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• 2015

To obtain the fundamental information on the dissolution of nickel into the slag in the pyrometallurgical processes for treatment of wasted PCB, the distribution ratios of nickel between CaO-$SiO_2-Al_2O_3$-MgO slag and copper-5 wt%Ni alloy were measured at 1623 K to 1823 K under a controlled $CO_2$-CO atmosphere. The distribution ratio of Ni increased linearly with increasing oxygen partial pressure. Therefore, the dissolution reaction of nickel into the slags could be described by the following equation; $$Ni(l)_{metal}+\frac{1}{2}O_2(g)NiO(l)_{slag}$$ The distribution ratio of Ni increased linearly with increasing content of basic oxides(CaO and MgO) in slag. However, the distribution ratio of Ni decreased linearly with increasing temperature. From these results, the empirical equation of distribution ratio of Ni was obtained by the following equation from the analysis of experimental conditions by multiple regression. $${\log}L_{Ni}=0.4000{\log}P_{O2}-5.1{\times}10^{-4}T+0.3375\(\frac{X_{CaO}+X_{MgO}}{X_{SiO2}}\)$$

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.59-72
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• 2009

In order to utilize sewage sludge as a heat source of energy, it goes without saying that the fuel should be clean and pose no threat to the environment. As a consequent, it should not contain even minute quantities of heavy metals / impurities. The SOCA (Sludge-Oil-Coal- Agglomerates) fuel can meet all these requirements. SOCA being a solid fuel can be gasified for the production of clean energy. Wet catalytic gasification is the most appropriate process for SOCA containing nearly 60% water. It is important to note that the SOCA thus obtained inherits ca. 40~50% of sulfur from the coal used. It can poison the catalyst during catalytic gasification process. Consequently, it becomes important to choose a proper catalyst for the gasification. Calcium was found to be ideal choice as a catalyst for the gasification of SOCA. The optimal gasification was performed at $850^{\circ}C$ with water vapor. The role of fuel-N is of utmost importance in the gasification of SOCA. The gasification should be controlled to reduce the production of HCN to a minimum and enhance its conversion to $N_2$ and/or $NH_3$.

• 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.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.79-89
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• 2003

The purpose of this study is to investigate appropriate environmental factors when domestic waste is decomposed as aerobic digestion. So stabilization degree was measured after the waste is mixed as certain rates and water content was controlled by 55% and 60%. Variation of VS showed food waste in reactors of number 1, 2, 3, 4 and 5 was decomposed fully except reactor of number 6. Decomposition degree of VS in reactors of number 1, 2, 3 and 4 was not different high because Vinyl and plastic inserted played role bulking agent in reactor number 1, 2, 3 and 4. In reactors, maximum temperature indicated $57{\sim}59^{\circ}C$ and temperatures in reactors 1, 2, 3 and 4 were higher and remained longer than in reactor 5 and 6 for 2~4 days. Variation of $CO_2$ was similar to that of VS. The reduction rate of water content was low because moisture generated by oxidation fever of microorganism did not evaporated well. pH was low in the beginning of the reaction however, as time passed, it increased slightly and remained regular pattern. EC and C/N showed the same pattern as pH. Settlement and weight reduction rates were similar to the factors above. Reactor 1, 2, 3, and 4 showed higher settlement and weight reduction rate than reactor 5 and 6.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.3-9
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• 2006

As a basic study on the conversion of molten converter slag to the ordinary portland cement, the effects of $Al_{2}O_{3}$ addition on the interface reaction between solid CaO and molten converter slag has been studied. Alumina added converter slag whose basicity was controlled to 1 and 2 was melted and hold for 30 minutes in MgO crucible at $1500^{\circ}C$. Then sintered CaO pellet heated at the same temperature was dipped into the molten slag and held for 30minutes. After the reaction, the crucible was cooled in air and the specimen was cut off to the horizontal direction of the crucible. The dissolution rate of CaO pellet with the addition of $Al_{2}O_{3}$ was measured by the change of the radius or sintered CaO pellet and the interface layer was observed by SEM/EDX. As a result. At the basicity 2 slag, thickness of created $C_{3}S$ layer increased 3.5 times and quantity of $C_{6}AF_{2}\;or\;C_{4}AF$ phase increase 2 times than baisicy 1 slag.