The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Joseph Tarradellas - One of the best experts on this subject based on the ideXlab platform.
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fate of pcbs pahs and their Source Characteristic ratios during composting and digestion of Source separated organic waste in full scale plants
Environmental Pollution, 2007Co-Authors: Rahel C Brandli, Thomas D Bucheli, Thomas S Kupper, Jochen Mayer, Franz X Stadelmann, Joseph TarradellasAbstract:Composting and digestion are important waste management strategies. However, the resulting products can contain significant amounts of organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). In this study we followed the concentration changes of PCBs and PAHs during composting and digestion on field-scale for the first time. Concentrations of low-chlorinated PCBs increased during composting (about 30%), whereas a slight decrease was observed for the higher chlorinated congeners (about 10%). Enantiomeric fractions of atropisomeric PCBs were essentially racemic and stable over time. Levels of low-molecular-weight PAHs declined during composting (50-90% reduction), whereas high-molecular-weight compounds were stable. The PCBs and PAHs concentrations did not seem to vary during digestion. Source apportionment by applying Characteristic PAH ratios and molecular markers in input material did not give any clear results. Some of these parameters changed considerably during composting. Hence, their diagnostic potential for finished compost must be questioned.
Rahel C Brandli - One of the best experts on this subject based on the ideXlab platform.
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fate of pcbs pahs and their Source Characteristic ratios during composting and digestion of Source separated organic waste in full scale plants
Environmental Pollution, 2007Co-Authors: Rahel C Brandli, Thomas D Bucheli, Thomas S Kupper, Jochen Mayer, Franz X Stadelmann, Joseph TarradellasAbstract:Composting and digestion are important waste management strategies. However, the resulting products can contain significant amounts of organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). In this study we followed the concentration changes of PCBs and PAHs during composting and digestion on field-scale for the first time. Concentrations of low-chlorinated PCBs increased during composting (about 30%), whereas a slight decrease was observed for the higher chlorinated congeners (about 10%). Enantiomeric fractions of atropisomeric PCBs were essentially racemic and stable over time. Levels of low-molecular-weight PAHs declined during composting (50-90% reduction), whereas high-molecular-weight compounds were stable. The PCBs and PAHs concentrations did not seem to vary during digestion. Source apportionment by applying Characteristic PAH ratios and molecular markers in input material did not give any clear results. Some of these parameters changed considerably during composting. Hence, their diagnostic potential for finished compost must be questioned.
Shigeki Masunaga - One of the best experts on this subject based on the ideXlab platform.
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behavior and Source Characteristic of pcbs in urban ambient air of yokohama japan
Environmental Pollution, 2005Co-Authors: Kyoungsoo Kim, Shigeki MasunagaAbstract:To understand the behavior and Sources of polychlorinated biphenyls (PCBs) in ambient air, gaseous and particulate phase concentrations were measured at Yokohama City, Japan, during March 2002 and February 2003. The concentration of total PCB and TEQ ranged from 62 to 250 pg/m3 and from 2 to 14 fgTEQ/m3, respectively. The gas-particle partition coefficient (Kp) was obtained as a function of temperature. The relationship between the partition coefficient and the sub-cooled liquid vapor pressure (PL) was also established (coefficients of determination for log Kp versus log PL plot were >0.76, except for three samples). As a result, the partition ratio of gaseous and particulate phase PCBs can be estimated for an arbitrary temperature. Principal component analysis (PCA) was applied to the Source identification of PCBs in ambient air. The concentrations of 122 congeners between tetra-CBs and deca-CB were used as input variables, and three PCs with eigenvalue more than 10 were obtained. The principal component 1 (PC 1) accounted for 43.4% of the total variance, and was interpreted as volatilization from PCB products and/or sites polluted by PCBs. The concentrations of PCB congeners were strongly related with PC 1 which showed high correlation with temperature. PC 2 accounted for 22.3%, and was interpreted as PCBs from incineration Sources, while PC 3 accounted for 10.8%, but could not be interpreted.
Jw Kim - One of the best experts on this subject based on the ideXlab platform.
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a study on prediction of welding current in gas metal arc welding part 1 modelling of welding current in response to change of tip to workpiece distance
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE, 1991Co-Authors: Jw KimAbstract:A model of the welding arc in gas metal arc welding (GMAW) is very useful for the analysis and automation of the welding process. Thus a mathematical model that is able to predict the welding current change in response to the variation of tip-to-workpiece distance was proposed for the gas metal arc welding process. The model was deveoped by analysing the welding arc behaviour and by considering the Characteristic of the welding power Source.The welding current variation was calculated with respect to various welding conditions and slope of the power Source Characteristic. By comparing the calculated and measured current signals, it could be concluded that the model proposed can well define the relation ship between welding current and tip-to-workpiece distance for various welding conditions in gas metal arc welding. Both the calculated and measured signals of welding current show almost a linear variation in response to the linear change of tip-to-workpiece distance
Franz X Stadelmann - One of the best experts on this subject based on the ideXlab platform.
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fate of pcbs pahs and their Source Characteristic ratios during composting and digestion of Source separated organic waste in full scale plants
Environmental Pollution, 2007Co-Authors: Rahel C Brandli, Thomas D Bucheli, Thomas S Kupper, Jochen Mayer, Franz X Stadelmann, Joseph TarradellasAbstract:Composting and digestion are important waste management strategies. However, the resulting products can contain significant amounts of organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). In this study we followed the concentration changes of PCBs and PAHs during composting and digestion on field-scale for the first time. Concentrations of low-chlorinated PCBs increased during composting (about 30%), whereas a slight decrease was observed for the higher chlorinated congeners (about 10%). Enantiomeric fractions of atropisomeric PCBs were essentially racemic and stable over time. Levels of low-molecular-weight PAHs declined during composting (50-90% reduction), whereas high-molecular-weight compounds were stable. The PCBs and PAHs concentrations did not seem to vary during digestion. Source apportionment by applying Characteristic PAH ratios and molecular markers in input material did not give any clear results. Some of these parameters changed considerably during composting. Hence, their diagnostic potential for finished compost must be questioned.