• Journal of Environmental Policy
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• v.2 no.1
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• pp.51-75
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• 2003

The objective of this study is to analyze the problems of disposal and collection, including administrative management of agricultural PE waste and suggest effective management measurements. Information regarding problems of agricultural PE waste management were collected from field survey of farmers, regional governments and officials. On the national level, the low ratio of collection for optimal treatment of agricultural PE waste is a critical problem. , the negative discharging behavior of farmers, an illegal incineration and landfill of farmers and a lack of education and extension etc. An ambiguity of the management principle to agricultural PE waste, the differences in management among the regional governments, a lack of will of the regional governments and officials to realize SARD and lack of education and extension etc. are some of the problems in administrative management of agricultural PE waste collection. The major suggestions of this study are as follows : (1) to strengthen education and extension, (2) to adopt an improved economic incentive system and strong, lawful regulation simultaneously, (3) to use temporang collection and permanent collection site, and (4) to organize "OTC(Optimal Treatment Conference)" composed of farmers, regional cooperative, PE producers etc. for operating an effective management system.

• Journal of Welding and Joining
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• v.29 no.1
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• pp.85-89
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• 2011

Waste water is disposed to sewage disposal plant by underground PE double wall pipes. Various processes have been introduced to join PE pipes, but most of these methods have many disadvantages such as costs, lack of reliability and difficulties in joining, etc. Recently butt welding has been paid much attention to joint PE pipes as this process has many advantages such as cost, safety and reliability. In this study, newly developed heat plate, a patent-pending heat plate with a groove, was used to butt-weld PE double wall pipes with different misalignment gaps to simulate real underground conditions, and the butt welding temperature of PE pipe was determined by thermal analysis (Thermal Gravimetric Analysis, Differential Scanning Calorimetry and Dynamic Mechanical Analysis). The resulting joining characteristics of double wall pipes were compared with those from a conventional heat plate, in terms of stiffness, flattening and leakage tests. The results from the stiffness and flattening test showed that there were no big differences between the butt-welded joints made from these two plates. From the leakage test, although PE pipes welded with a conventional heat plate did leak below the required test conditions (10 min. at 0.75kgf/cm2), the pipes welded with a patent-pending grooved heat plate did not show any leakage even at a pressure 1.5 times higher than the required conditions. It was noted that by utilizing a grooved heat plate more complete fusion at the pipe joints could be obtained, which in turn induced a high quality joints.

• Resources Recycling
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• v.6 no.2
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• pp.22-28
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• 1997

In recent yean thc problem of wastc plastics arc greatly incrcascd with ihe result uf lndushial growth. As a rcsult the amount of wastc plaslics in domestic area is appraxhnately 2,300,000 t<~nin 1996 base and contmuously increasing more than 12% cvcry ycar. Thc disposal way of these waste plastics arc dlLl malnly rely~ng on landill1 or partially incinuralion So that it hss become a senous social problem due to the second envirnmentd pollution. The tcchnologics iar prducing oil from the waste plastics have hccn dcvelopcd far along pennd and currently some of them are in a commercialiration stage Pyrolysis process in one of the major process m heating waslc plaslics bul still has some restlichons for the cammcrc~dizatian duc lo 11s emnom~cal problems assaciated with a systcmiltlc lecd collcctionidispnsJ ways. Cansldenng cnvaomcnld problems, thc inclease m the charge for waste matcds trcatmcnt and thc lmlitarion ni disposal area, it is inteicstcd that the wastc plastics treabncnt by pyrolysn. which would be the safest and the most eilic~ent process for cnnvcrting fecd wastc to rc-usablc rcsourccs. would he predomhant m ihe near h~lurc Thc shldy aims inr the development of haslc ted~nolagy for scaling up to a com~nercial sire through pyrolys~s process which is cnnduclcd under the absence of air. Furthern~orc the waste plastics can be recycled as iual gas or oil wilhout harmful effects in enviroment, The waste w e d plastics arc pyrolyzed in (he fluidized bcd rcaclor under continuous way and thc ail ylcld gives approx~marcly 47 4%.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.3
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• pp.313-324
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• 2024

Se sorption onto Ca-type montmorillonite purified from Bentonil-WRK-a new research bentonite introduced by Korea Atomic Energy Research Institute-was examined under ambient conditions (pH 4-9, pe 7-9, I = 0.01 M CaCl₂, and T = 25℃). Se(IV) was identified as the oxidation state responsible for weak sorption (Kd < 22 L·kg^-1) by forming surface complexes with edge functional groups of the montmorillonite. Thermodynamic modeling, considering reaction mechanisms of outer-sphere complexation (≡AlOH⁺₂ + HSeO₃^- ⇌ ≡AlOH₃SeO₃, log K = 0.50 ± 0.21), inner-sphere complexation (2≡AlOH + H₂SeO₃(aq) ⇌ (≡Al)₂SeO₃ + 2H₂O(l), log K = 7.89 ± 0.51), and Ca²⁺-involved ternary complexation (≡AlOH + Ca²⁺ + SeO₃^2- ⇌ ≡AlOHCaSeO₃, log K = 7.69 ± 0.28) between selenite and aluminol sites of montmorillonite, acceptably reproduced the batch sorption data. Outer- and inner-sphere complexes are predominant Se(IV) forms sorbed in acidic (pH ≈ 4) and near-acidic (pH ≈ 6) regions, respectively, whereas ternary complexation accounts for Se(IV) sorption at neutral pHs under the ambient conditions. The experimental and modeling data generally extend a material-specific sorption database of Bentonil-WRK, which is essential for assessing its radionuclide retention performance as a buffer candidate of deep geological disposal system for high-level radioactive waste.