Extensive laboratory experiments were carried out to investigate the uniform-shear flow approaching a circular cylinder. The aim was to present the Strouhal number (St)-Reynolds number (Re) diagrams over a broad range of the shear parameter K (0 < K < 0.25) and at higher values of Re (600 < Re < 1600). An image processing technique, in conjunction with flow visualization studies, was used to secure more quantitative depictions of vortex shedding from the cylinder. The Strouhal number increases with increasing shear parameter. The drag coefficient decreases with increasing Re; also, C d decreases as the shear parameter K increases.

Soil pollution around railroad sites is mainly caused by heavy oils such as diesel and lubricants. In particular, the majority of contamination in soil around railroad turnouts is caused by oil that drips off of railcars and lubricants that leak during vehicle maintenance. Generally, removing lubricants from contaminated soil is more difficult than removing diesel, due to the properties of the respective oils. This study aims to investigate alternative remediation method of lubricant-contaminated soils around railroad turnouts. The EK-Fenton process was used to clean up the lubricant-contaminated railroad soil. Several operating conditions were tested, including the concentration of hydrogen peroxide, and electrolyte types and concentrations. We determined that the removal efficiency was affected by the amount of EOF in the soil and its oxidizing capacity. The TPH removal efficiency was greatest at 0.1 M of NaCl electrolyte and 5 % (v/v) of hydrogen peroxide. This shows that the in-situ EK-Fenton process is a promising remediation technique for decontaminating railroad soil polluted with lubricant oil.

The wooden sleeper laid in the railroad is highly contaminated by the preservative such as creosote used in the production process. And the secondary contamination of wooden sleeper happened from the leakage of diesels and lubricant oils. Recently the concrete sleeper has replaced the wooden sleepers. But the wooden sleepers are still used and the huge amount of waste wooden sleeper are discharged every year. Due to the environmental toxicity of contaminants in waste wooden sleeper, the waste wooden sleeper is categorized as the specified waste and its disposal should be carefully conducted. But there is not alternative method except the incineration. In this study, the thermal extraction characteristics of waste wooden sleeper in high temperature were investigated to observe the feasibility of the disposal and reuse of waste wooden sleeper.

No abstract

Soil pollution around railroad sites is mainly caused by heavy metals and oils. In this study, electrokinetic (EK) remediation was tested to remediate the heavy metal-contaminated railroad soil. The main pollutants of the soil were Cd, Cu, Pb and Zn. The used reactor was 2-D scale and DC electric current was supplied continuously under 2 V/cm. As a result, the total removal efficiency of heavy metals from the contaminated railroad soil was about 55.2 %. In the future, the additional researches are required to enhance the removal efficiency for the residual concentration of heavy metals in soil under the remediation standard levels designated from the Soil Environment Preservation Act in Korea.