• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.649-659
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• 2023

This study was initiated to evaluate the phosphorus (P) removal and diesel oil degradation by bacteria isolated from industrial wastewater. The bacteria isolated were identified as Bacillus sp. The P removal efficiencies by Bacillus sp. were 99% at the initial 20 mg/L P concentration. The diesel degradation efficiencies by Bacillus sp. were 86.4% at an initial 1% diesel concentration. Lipophilicity by bacteria was the highest in the log phase, whereas it was the lowest in the death phase. As the diesel was used as a carbon source, P removal efficiencies by Bacillus sp. were 68%. When glucose, acetate, and a mixture of glucose and acetate as second carbon sources were added, the diesel degradation efficiencies were 69.22%, 65.46%, and 51.46%, respectively. The diesel degradation efficiency was higher in the individual additions of glucose or acetate than in the mixture of glucose and acetate. When P concentration increased from 20 mg/L to 30 mg/L, the diesel degradation efficiency was increased by 7% from 65% to 72%, whereas when P concentration was increased from 30 mg/L to 40 mg/L, there was no increase in diesel degradation. One of the five proteins identified by proteome analysis in the 0.5% diesel-treated samples may be involved in alkane degradation and is known as the cytochrome P450 system. Also, two of the sixteen proteins identified in the 1.5% diesel-treated samples may be implicated in the fatty acid transport system and alcohol dehydrogenation.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1439-1446
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• 2009

Isocarbophos is a widely used organophosphorus insecticide that has caused environmental pollution in many areas. However, degradation of isocarbophos by pure cultures has not been extensively studied, and the degradation pathway has not been determined. In this paper, a highly effective isocarbophos-degrading strain, scl-2, was isolated from isocarbophos-polluted soil. The strain scl-2 was preliminarily identified as Arthrobacter sp. based on its morphological, physiological, and biochemical properties, as well as 16S rDNA analysis. The strain scl-2 could utilize isocarbophos as its sole source of carbon and phosphorus for growth. One hundred mg/l isocarbophos could be degraded to a non detectable level in 18 h by scl-2 in cell culture, and isofenphos-methyl, profenofos, and phosmet could also be degraded. During the degradation of isocarbophos, the metabolites isopropyl salicylate, salicylate, and gentisate were detected and identified based on MS/MS analysis and their retention times in HPLC. Transformation of gentisate to pyruvate and fumarate via maleylpyruvate and fumarylpyruvate was detected by assaying for the activities of gentisate 1,2-dioxygenase (GDO) and maleylpyruvate isomerase. Therefore, we have identified the degradation pathway of isocarbophos in Arthrobacter sp. scl-2 for the first time. This study highlights an important potential use of the strain scl-2 for the cleanup of environmental contamination by isocarbophos and presents a mechanism of isocarbophos metabolism.

• Journal of Conservation Science
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• v.27 no.2
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• pp.155-162
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• 2011

In case of leather objects, degradation usually occurs by a combination of factors such as temperature and relative humidity, light and insect and fungi. Because chemical composition differs on the types of leather materials, leather objects affect differently even in the same environment. According to UV degradation, the overall color and gloss difference appeared severe in turn of the cowskin, sheepskin and pigskin specimens. In addition, despite short-term period of RH degradation, leather materials showed stable result on high RH circumstances. Nevertheless, if the leather sustained for a long time on the high RH, the environment can be the cause of mold or microorganisms. This study is to understand the leather objects and the future conservation and then to establish the conservational management of leather object for the future.

• Asian Journal of Business Environment
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• v.12 no.1
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• pp.17-24
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• 2022

Purpose: This study aims to determine the effect of economic agents, such as the amount of government expenditure on the environment, households, manufacturing industry, and shipping activities; on environmental degradation in Indonesia. Research design, data, and methodology: This study is conducted with 264 observations from panel data of 33 provinces during 2010-2017. Environmental degradation is measured by using the environmental quality index collected from Indonesian Ministry of Forestry and Indonesian Central Bureau of Statistics. Three testing models are used to test the panel data, namely Common Effect Model (CEM), Fixed Effect Model (FEM), and Random Effect Model (REM). Results: The research findings show that the amount of government expenditure on the environment, households, and shipping activities have a negative and significant effects on environmental degradation, while the number of manufacturing industry has positive and significant effect on environmental degradation. Unlike the previous studies, the result also shows that government expenditure on environmental has a positive and significant effect on environmental quality index. Conclusion: It can be concluded that even though Indonesian government spent a low budget on environment, their environmental regulation has succeeded both in reducing environmental degradation and increasing the environmental quality as indicated by Indonesian environmental quality index.

• Journal of Conservation Science
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• v.2 no.2 s.2
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• pp.15-24
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• 1993

To understand the morphological change of ancient woods, samples classified by cell type, burial environment and species were collected and observed using microscopy. Decay of wood by cell type could classified into two types. First, degraded secondary wall was formed granular residues in $S_2$ layer and was remained $S_3$ layer and compound middle lamella. Second, the cell wall was slightly degraded and cracked in secondary wall. A gradual thinning of cell wall was occured. The compound middle lamella was separated from secondary wall. The resistance of degradation is increased at vessels, parenchyma, and tracheid and wood fiber in the order named. The type of degradation by species could be classified into four types. Overall degradation type; the degradation of cell wall is usually heavy and the extent of degradation Varies by part of the same sample. Partial degradation type ; this type shows severely different decay type by part of the sample. Nondegraded cells were mixed with degraded cells on the same sample. Erose degradation type ; thinning of the cell wall was occoured and the degradation type was different by part. Slight degradation types ; secondary wall was slightly degraded, cracked and separated from compound middle lamella. Considering different type of burial environment, dry wood was similiar to sound wood and slightly decayed. Waterlogged and peat burial wood was heavilydecayed. Between species of under the same environment, decay type and extent were diferentiated from each other.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.128-131
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• 2001

We evaluated natural attenuation of petroleum hydrocarbons in a shallow aquifer using a modeling study. The studied shallow aquifer was severely contaminated with petroleum hydrocarbons, especially toluene, ethylbenzene and xylenes (i.e, TEX). The exact spill history was not known. Therefor we used a contaminant level in May 1999 (the first sampling date of our integrated study) as an initial contaminant concentration. we calibrated required transport parameters using the contamination levels obtained from groundwater analyses in September of 1999. For fate and transport of the petroleum contaminants, five case 2 with sorption and degradation. case 3 with sorption and degradation (half decay constant compared with case 2), case 4 with degradation but no sorption, and case 5 with sorption but no degradation. For sorption and degradation, a linear sorption isotherm and first order irreversible decay was assumed, respectively and no additional contamination source to groundwater is also assumed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.53-56
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• 2001

The degradation of tetrachloroethene (PCE) and trichloroethene (TCE) by vitamin B$_{12}$, an electron mediator was examined when zero valent metals (ZVMs) were used as built electron donors. Dechlorination of PCE and TCE by iron and zinc in the presence of vitamin B$_{12}$ showed that the zinc and vitamin B$_{12}$ combination greatly enhances the reaction rates for both PCE and TCE, but iron and vitamin B$_{12}$ result in an increase in reactivity only for PCE degradation, not for TCE degradation in comparing with meta]s only. This result indicates vitamin B$_{12}$(I) Is active towards both PCE and TCE degradation while vitamin B$_{12}$(II) is active towards both PCE. Calculated activation energies for the dechlorination of PCE in the presence of Vitamin B$_{12}$ showed that vitamin B$_{12}$ lowered the activation energy about 40-60 kJ/㏖ for the both metals.the both metals.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.43-47
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• 2002

Weight loss experiments have been performed for unidirectional carbon fiber/epoxy laminates under both isothermal and cyclic thermal conditions. It was found that weight losses were the result of both specimen-geometry dependent oxidative degradation and volumetric geometry dependent thermal degradation. Thermal degradation was found to play a major role in the overall weight loss process, and photomicrographs of cross-sectioned, aged specimens confirmed this fact. A method to predict the effect of isothermal environment on the weight loss was introduced and found to be in good agreement with experimental data at temperatures near Tg (glass transition temperature).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.1
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• pp.11-19
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• 2016

This paper focuses on the estimation of durability and service-life of reinforced concrete structures in Wolsong Low- and intermediate-level wastes Disposal Center (WLDC) in Korea. There are six disposal silos located in the saturated environment. The silo concrete is degraded due to reactions with groundwater and chemical attacks, and finally it will lose its properties as a transport barrier. The infiltration of sulfate and magnesium, leaching of potassium hydroxide, and chlorine induced corrosion are the most significant factors for degradation of reinforced concrete structure in underground environment. From the result of evaluation of the degradation time for each factor, the degradation rate of the reinforced concrete due to sulfate and magnesium is $1.308{\times}10^{-3}cm/yr$, and it is estimated to take 48,000 years for full degradation while potassium hydroxide is leached in depth of less than 1.5 cm at 1,000 years after the initiation of degradation. In case of chlorine induced corrosion, it takes 1,648 years to initiate corrosion in the main reinforced bar and 2,288 years to reach the lifetime limit of the structural integrity, and thus it is evaluated as the most significant factor.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.49-56
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• 2013

The entire land of Southern Iran faces problems arising out of various types of land degradation of which vegetation degradation forms one of the major types. The present work introduces a model developed for assessing the current status of hazard of vegetation degradation using Geographic Information System (GIS). This kind of assessment differs from those assessments based on vulnerability or potential hazard assessments. The Sadra watershed which covers the upper reaches of Marharlu basin, Fars Province, has been chosen for a hazard assessment of this type of degradation. The different kinds of data for indicators of current status of vegetation degradation were gathered from collecting of field data and also records of the governmental offices of Iran. Taking into consideration three indicators of current status of vegetation degradation the model identifies areas with different hazard classes. By fixing the thresholds of severity classes of the three indicators including per cent of vegetation cover, biomass production and ratio of actual biomass to potential biomass production, a hazard map for each indicator was first prepared in GIS. The final hazard map of current status of vegetation degradation was prepared by intersecting three hazards in the GIS. Results show areas under severe hazard class have been found to be widespread (89 %) while areas under moderate and very severe hazard classes have been found less extensive in the Sadra watershed. The preparation of hazard maps based on the GIS analysis of these indicators will be helpful for prioritizing the areas to initiate remedial measures.