Expanded Polystyrene Foam Formed from Polystyrene Beads Coated with a Nanocrystalline SiO2 Film and the Analysis of Its Moisture Adsorption and Resistance to Mechanical Stress

Conventional expanded polystyrene can absorb moisture, which significantly degrades its properties. In the present study, it was demonstrated that SiO₂ can be deposited on polystyrene beads before pre-expansion and molding steps. Under the applied test conditions, expanded polystyrene with nanocrystalline SiO₂ additives had approximately 10% lower moisture adsorption and an 8.4% better resistance to deformation. Expanded polystyrene analysis suggested that the observed improvements were caused by the hydrophobic nature of nanocrystalline SiO₂ and, even more importantly, because SiO₂ acted as an amalgamation catalyst and significantly increased adhesion between the expanded polystyrene beads during the expanded polystyrene molding process.     

Comparative assessment of future motor vehicles under various climate change mitigation scenarios

The aim of comparative assessment of future road transport technologies is to find the cheapest motor vehicles in terms of private and external Greenhouse Gas (GHG) emission costs under various international climate change mitigation scenarios in 2020 and 2050. The comparative assessment of the main road transport technologies ranging from conventional vehicles to hybrid electric vehicles was performed. The main indicators for comparative future motor vehicles assessment are: private costs and life cycle external costs of GHG emissions. The obtained ranking of road transport technologies allows to identify the most perspective future motor vehicles taking into account international climate change mitigation constraints and to promote these road technologies by policy tools. The cheapest road transport technologies in 2020 and 2050 are: the main results presented in this paper were obtained during EU financed Framework 7 project “PLANETS” dealing with probabilistic long-term assessment of new energy technology scenarios.     

Ventilation and posture effects on inhalation exposures to volatile cleaning ingredients in a simulated domestic worker cleaning environment

Associations between cleaning chemical exposures and asthma have previously been identified in professional cleaners and healthcare workers. Domestic workers, including housecleaners and caregivers, may receive similar exposures but in residential environments with lower ventilation rates. Study objectives were to compare exposures to occupational exposure limits (OELs), to determine relative contributions from individual cleaning tasks to overall exposure, and to evaluate the effects of ventilation and posture on exposure. Airborne chemical concentrations of sprayed cleaning chemicals (acetic acid or ammonia) were measured during typical cleaning tasks in a simulated residential work environment. Whole-house cleaning exposures (18 cleaning tasks) were measured using integrated personal sampling methods. Individual task exposures were measured with a sampling line attached to subjects' breathing zones, with readings recorded by a ppbRAE monitor, equipped with a photoionization detector calibrated for ammonia and acetic acid measurements. Integrated sampling results indicated no exposures above OELs occurred, but 95th percentile air concentrations would require risk management decisions. Exposure reductions were observed with increased source distance, with lower exposures from mopping floors compared to kneeling. Exposure reductions were also observed for most but not all tasks when ventilation was used, with implications that alternative exposure reduction methods may be needed.     

Electrokinetic soil remediation--critical overview

In recent years, there has been increasing interest in finding new and innovative solutions for the efficient removal of contaminants from soils to solve groundwater, as well as soil, pollution. The objective of this review is to examine several alternative soil-remediating technologies, with respect to heavy metal remediation, pointing out their strengths and drawbacks and placing an emphasis on electrokinetic soil remediation technology. In addition, the review presents detailed theoretical aspects, design and operational considerations of electrokinetic soil-remediation variables, which are most important in efficient process application, as well as the advantages over other technologies and obstacles to overcome. The review discusses possibilities of removing selected heavy metal contaminants from clay and sandy soils, both saturated and unsaturated. It also gives selected efficiency rates for heavy metal removal, the dependence of these rates on soil variables, and operational conditions, as well as a cost-benefit analysis. Finally, several emerging in situ electrokinetic soil remediation technologies, such as Lasagna, Elektro-Klean, electrobioremediation, etc., are reviewed, and their advantages, disadvantages and possibilities in full-scale commercial applications are examined.     

An ecotoxicity assessment of contaminated forest soils from the Kola Peninsula

Point source copper and nickel contamination emanating from smelters of the Kola Peninsula, NW Russia, has been observed since the mid-1960s. Previous studies have concentrated on the spatial distribution of heavy metals and their effects on forest ecology and indigenous mammals and birds. Soil is perceived as the major repository for the metal pollutants but there is a need to link the soil concentration of pollutants on the Kola Peninsula with biological parameters. Many standard methods currently used in soil ecotoxicology are developed and refined with artificial amendments and rarely modified for use in historically contaminated environments. In this study, forest soils were sampled along a 34 km transect from the smelter and analysed both chemically and with a range of ecologically relevant biological tests. Soil respiration, total nematode count, microbial heterotrophic numbers and minimal inhibitory concentrations to copper and nickel were carried out on bulk soil. The soil pore water was tested with bacterial and fungal bioluminescence-based biosensors. The heterotrophic numbers and their inhibitory concentration showed strong correlation with heavy metal concentrations while decreasing biosensor luminescence was related to increasing copper concentrations present in the pore waters. Overall, there were considerable impacts on some microbial parameters but other measures including respiration and nematode populations were insensitive to pollutant levels. While chemical analysis of heavy metals proved essential in defining the extent of contamination, environmentally relevant ecotoxicological tests complemented these data by demonstrating pollutant impact. Ecotoxicological approaches that study both the bulk soil and pore water may represent the key to understanding the fate of heavy metal in soils.     

Evaluation and prediction of emissions from a road built with bottom ash from municipal solid waste incineration (MSWI)

In autumn 2001, a full-scale test road was built with municipal solid waste incineration (MSWI) bottom ash at the D?vamyran landfill, Ume?, Northern Sweden. Leachates were collected from asphalted sections with either bottom ash or gravel as filling material. In this research, 12 months of ash leachate sampling were evaluated with respect to emissions of contaminants such as trace metals and chlorides (Cl). The usefulness of regression models describing trace metal mobility from bottom ash was also tested as predictive tools for reusability applications of MSWI bottom ash. Cl, Cu, and Cr had the highest mobility (considering leachate concentrations) in the ash leachate, though concentrations of Cl and Cu decreased during the sampling period (Cl from 10,000 to 600 mg l(-1); Cu from 1600 to 500 microg l(-1)). An increased mobility of Cr during the autumns (about 3-4 times higher compared to the summer) was noted with a maximum value of nearly 70 microg l(-1) during autumn 2001. Pb showed a very low mobility over the entire year with leachate concentrations of around 3-4 microg l(-1). Chemical equilibrium calculations using Minteq indicated that several Cu minerals were oversaturated in the leachate, thus mineral precipitation could be responsible for declining amounts of Cu in the leachate. Adsorption to iron oxides was found to be a probable explanation for the low mobility of Pb. A reasonably good agreement between regression models and field values were achieved for Ni, Pb, Zn, and Cu, while the models for Cd and Cr were less promising. Even though a large part of the variation (R2=61-97%) in the leaching experiment could be explained by only pH and L/S, field data were much more scattered than expected from field pH.     

Electrode Layout and Process Kinetics of Electroremoval of Copper from Sand

This research paper concentrates on the efficiency of electrokinetic remediation of copper contaminated sand employing different electrode material, number and spacing. By optimising the selection of suitable electrode materials, coupled with the application of the appropriate number of electrodes and electrode spacing, it is expected that the remediation time will be drastically reduced. In addition, the methodology being investigated in this study will reduce inefficiencies in electrical field distribution. The effect of various electrode materials such as silver and graphite, and the influence of changes in the number and the layout of the electrodes on the overall remediation efficiency and time was investigated and evaluated. Experiments with one, two and three one-dimensional anode system have proved that remediation efficiencies as high as 91% can be attained.     

Evaluation of UV LEDs Performance in Photochemical Oxidation of Phenol in the Presence of H2O2

A novel application of ultraviolet (UV) light emitting diodes (LEDs) as a light source for the degradation of organic contaminant has been investigated. Photocleaving of hydrogen peroxide (H2O2) via UV LEDs photolysis resulted in the generation of hydroxyl radicals. It was found that phenol removal was insignificant in the absence of hydrogen peroxide, therefore oxidation of phenol was attributed to the formed radicals. Two criteria were selected to provide detailed information on the performance of UV LEDs in phenol oxidation: (1) the reaction quantum efficiency and (2) the energy consumption. Statistical tools such as the response surface methodology and the ANOVA were applied to estimate the influence of various process parameters such as the wavelength (255, 269, and 276 nm) and H2O2 to phenol molar ratio (5, 50, and 100) on phenol degradation reaction quantum efficiency. The decay of phenol (initial concentration of 1.06 mM) was the most pronounced at 255 nm and H2O2 to phenol molar ratio of 50. Finally, the “figure-of-merit” was used to estimate the specific energy consumption of the UV LED-based process.     

Evaluation of UDP‐GlcN Derivatives for Selective Labeling of 5‐(Hydroxymethyl)cytosine

5‐(hydroxymethyl)cytosine (5‐hmC) is a newly identified oxidative product of 5‐methylcytosine (5‐mC) in the mammalian genome, and is believed to be an important epigenetic marker influencing a variety of biological processes. In addition to its relatively low abundance, the fluctuation of 5‐hmC levels over time during cell development poses a formidable challenge for its accurate mapping and quantification. Here we describe a specific chemoenzymatic approach to 5‐hmC detection in DNA samples by using new uridine 5′‐diphosphoglucosamine (UDP‐GlcN) probes. Our approach requires modification of the glucose moiety of UDP‐Glc with small amino groups and transfer of these glucose derivatives to the hydroxy moiety of 5‐hmC by using T4 phage glucosyltransferases. We evaluated the transfer efficiencies of three glucosyltransferases (wild‐type α‐ and β‐GTs and a Y261L mutant β‐GT) with five different UDP‐Glc derivatives containing functionalized groups for subsequent bioconjugation and detection. Our results indicate that UDP‐6‐N₃‐Glc, UDP‐6‐GlcN, and UDP‐2‐GlcN can be transferred by β‐GT with efficiencies similar to that seen with the native UDP‐Glc cofactor. 6‐N₃‐Glc‐ and 6‐GlcN‐containing oligonucleotides were selectively labeled with reactive fluorescent probes. In addition, a 2 kb DNA fragment modified with 2‐GlcN groups was specifically detected by use of a commercially available antiglucosamine antibody. Alternative substrates for β‐GT and correlated glycosyltransferases might prove useful for the study of the function and dynamics of 5‐hmC and other modified nucleotides, as well as for multiplex analysis.