• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.130-134
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• 2001

Recently environmental pollution at sea becomes serious, so every governmental organization makes its effort to solve this problem. Combustible ocean wastes as of ropes, fishing nets, and tires are usually highly polymerized compound materials. The problem of ocean waste treatment can be solved by using the pyrolysis method. Pyrolysis characteristics of ocean waste was examined to get the basic data for the production system of fuel from the ocean waste. Thermogravimetric experiment showed that residual mass rate decreases as the velocity of temperature-rising becomes lower. The pyrolysis of waste rope and fishing net occurs at 300~450$^{\circ}C $ and the waste tire does at 350~450$^{\circ}C $. Pyrolysis time is estimated about 15 to 20 minutes in the temperature range when lively act of pyrolysis temperature reached.

• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.87-94
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• 2007

This study used POM (Princeton ocean model) improved for applying to coastal area in order to predict the distribution of thermal waste water. This model was applied to the coastal circulation and the effect of thermal waste water of Cheonsu-Bay. So this study compared the discharge of thermal waste water with each layer and section. The tidal current was about 1.5 m/sec at surface level and 0.9 m/sec on bottom level at flood tide; tidal current was about 1.3 m/sec on surface level and 0.8 m/sec on bottom level at ebb tide. The method discharging the thermal waste water in the nearshore region (case 1) accelerates the diffusion of the thermal waste water in the north-south direction(longshore direction). However, the method discharge the thermal waster water in the offshore region (case 2) reduced the diffusion of the thermal waste water over the coastal region. According th the diffusion region of the thermal waste water with case 1 and case 2 at three different layers (surface, middle, bottom), the diffusion region by case 1 discharge method generally influenced wider region (twice) than the one by case 2 discharge method with lower temperature between $1^{\circ}C\;and\;2^{\circ}C$, whereas the case 2 discharge method influenced the deeper region (middle and botton layers) with higher change of the water temperature ($1{\sim}3^{\circ}C$).

• Journal of Ocean Engineering and Technology
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• v.23 no.3
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• pp.20-29
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• 2009

This study investigated the shear strength characteristics of waste tire powder-added lightweight soil (WTLS), which were developed to recycle dredged soil, bottom ash, and waste tires. The WTLS used in this experiment consisted of dredged soil, bottom ash, waste tire powder, and cement. Test specimens were prepared with various contents of waste tire powder ranging from 0% to 100% at 25% intervals and bottom ash contents of 0% or 100% by the weight of the dry dredged soil. In this study several series of direct shear tests were carried out, which indicated that the shear properties of WTLS were strongly influenced by the mixing conditions, such as the waste tire powder content and bottom ash content. The unit weight, as well as the shear strength of the WTLS, decreased with an increase in waste tire powder content. The shear strength of WTLS with bottom ash was 1.34 times greater than that of WTLS without bottom ash. An average increase in cohesion of 30 kPa was obtained in WTLS with the inclusion of bottom ash due to the bond strength induced from the pozzolanic reaction of the bottom ash. In this test, the maximum value of the internal friction angle was obtained with a 25% content of waste tire powder.

• Journal of Ocean Engineering and Technology
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• v.22 no.5
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• pp.112-118
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• 2008

The purpose of this study was to determine the engineering and environmental properties of the waste tire powder-added lightweight soil (TLS) used as flowable backfill. The TLS used in this experiment consisted of dredged soil, bottom ash, waste tire powder and cement. Test specimens were prepared with various contents of waste tire powder ranging from 0% to 100% at 25% intervals and water contents ranging from 140% to 200% by the weight of the dry dredged soil. Several series of unconfined compression tests, flow tests, and leaching tests were carried out. Experimental results for the TLS indicated that the unconfined compressive strength, secant modulus (), and unit weight of the TLS decreased with an increase in waste tire powder content. However, as the waste tire powder content increased, the stress-strain relationship of the TLS showed more ductile behavior rather than brittle behavior. The flow value increased with an increase in water content, but decreased with an increase in waste tire powder content. The result of the leaching test showed that the leaching amounts of heavy metals were lower than the permitted limits suggested by the Ministry of Environment.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.44-49
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• 2005

This paper investigates strength characteristics and stress-strain behaviors of unreinforced and reinforced lightweight soils. Lightweight soil, composed of dredged soil, cement, and air-foam, was reinforced by a waste fishing net, in order to increase its compressive strength. Test specimens were fabricated by various mixing conditions, such as cement content, initial water content, air content, and waste fishing net; then, unconfined compression tests were carried out on these specimens. From the test results, it was shown that reinforced lightweight soil had different behavior after failure, even though it had similar behavior as unreinforced lightweight soil before failure. The test results also showed that stress became constant after peak strength in reinforced lightweight soil, while the stress decreased continuously in unreinforced lightweight soil. It was observed that the strength was increased due to reinforcing effect by the waste fishing net for most cases, except high water content greater than $218\%$. In the case of high water content, a reinforcing effect is negligible, due to slip between waste fishing net and soil particles. In reinforced lightweight soil, secant modulus (E50) was increased, due to the inclusion of waste fishing net.

• Geomechanics and Engineering
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• v.19 no.4
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• pp.307-314
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• 2019

Light construction waste (LCW) particles are pieces of light concrete or insulation wall with light quality and certain strength, containing rich isolated and disconnected pores. Mixing LCW particles with soil can be one of the alternative lightweight soils. It can lighten and stabilize the deep-thick soft soil in-situ. In this study, the unconfined compressive strength (UCS) and its mechanism of Construction Waste Stabilized Lightweight Soil (CWSLS) are investigated. According to the prescription design, totally 35 sets of specimens are tested for the index of dry density (DD) and unconfined compressive strength (UCS). The results show that the DD of CWSLS is mainly affected by LCW content, and it decreases obviously with the increase of LCW content, while increases slightly with the increase of cement content. The UCS of CWSLS first increases and then decreases with the increase of LCW content, existing a peak value. The UCS increases linearly with the increase of cement content, while the strength growth rate is dramatically affected by the different LCW contents. The UCS of CWSLS mainly comes from the skeleton impaction of LCW particles and the gelation of soil-cement composite slurry. According to the distribution of LCW particles and soil-cement composite slurry, CWSLS specimens are divided into three structures: "suspend-dense" structure, "framework-dense" structure and "framework-pore" structure.

• Environmental Analysis Health and Toxicology
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• v.25 no.1
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• pp.11-18
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• 2010

Toxicity assessment of ocean dumping wastes (dye waste, urban sewage, food waste) were examined in the fertilization and embryo development rates of the Sea Urchin, Hemicentrotus pulcherrimus. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiments were began within 30 min the collection of both gametes. The fertilization and embryo development rates test were performed for 10 min and 64 h after fertilization, respectively. The fertilization and embryo development rates in the control condition (not including ocean dumping wastes sludge elutriate) were greater than 90%, but suddenly decreased with increasing of ocean dumping waste sludge elutriate concentrations. The fertilization and normal embryogenesis rates were significantly inhibited in all waste sludge elutriate from dye waste ($EC_{50}$=4.37; $EC_{50}$=1.76), urban sewage ($EC_{50}$=5.79; $EC_{50}$=2.00) and food waste ($EC_{50}$=7.68; $EC_{50}$=2.16), respectively. The NOEC (<3.13) and LOEC (3.13) of fertiliztion and normal embryogenesis rates very similar in all waste sludge elutriate. These results suggest that biological assay using the fertilization and embryo development rates of H. pulcherrimus are very useful test method for the ecological toxicity assessment of ocean dumping wastes.

• Environmental Analysis Health and Toxicology
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• v.24 no.1
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• pp.25-32
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• 2009

Toxicity of ocean dumping wastes(dye waste, urban sewage, food waste) were examined by observing fertilization and embryo development rates of the Sea Urchin, Strongylocentrotus nudus. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiments were began within 30 min after the collection of both gametes. The fertilization and embryo development rates tests were performed for 10 min and 48 h after fertilization, respectively. The fertilization and embryo development rates in the control condition(not including ocean dumping wastes sludge elutriate) were greater than 90%, but markedly decreased with increasing concentrations of ocean dumping waste sludge elutriate. The fertilization and normal embryogenesis rates were significantly inhibited in all waste sludge elutriate from dye waste($EC_{50}$=5.76; $EC_{50}$=4.53), urban sewage($EC_{50}$=9.82; $EC_{50}$=9.67) and food waste($EC_{50}$=3.90; $EC_{50}$=3.27), respectively. The NOEC(>3.13%) and LOEC(3.13%) of fertiliztion and normal embryogenesis rates very similar in all waste sludge elutriate. These results suggest biological assay using the fertilization and embryo development rates of S. nudus are very useful test method for the ecological toxicity assessment of ocean dumping wastes.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.135-139
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• 2000

Waste landfill consists of cover layer, glass, robber, sheet, food waste, etc and is in very loose state. So, the proper method must be applied to ground improvement of waste landfill according to its characteristics and conditions. In this paper, analysis for field tests as static loading test, bearing capacity test were performed. In result, PG pile method proved to be effective and economic, because it affected increase of end bearing capacity, the prevention of differential settlement and over 20% increase of density by expansion of pile.

• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.52-58
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• 2010

This study investigated the engineering properties of waste tire powder-bottom ash added composite soil, which was developed to recycle dredged soil, bottom ash, and waste tire powder. Test specimens were prepared using 5 different percentages of waste tire powder content(0%, 25%, 50%, 75%, and 100% by weight of the dry dredged soil), three different percentages of bottom ash content (0%, 50%, and 100% by weight of the dry dredged soil), and three different particle sizes of waste tire powder (0.1~2 mm, 0.9~5 mm, and 2~10 mm). Several series of unconfined compression tests, direct shear tests, and flow tests were conducted. The experimental results indicated that the waste tire powder content, particle size of waste tire powder, and bottom ash content influenced the strength and stress-strain behavior of the composite soil. The flow value increased with an increase in water content, but decreased with an increase in waste tire powder content.