A laboratory feasibility study on electrokinetic injection of nutrients on an organic, tropical, clayey soil

Based on the results of an environmental investigation program, carried out on an oil production field at Brazilian Northeast, a contamination diagnosis was made. The field was contaminated by crude oil and saline production water and the use of in situ electrokinetic bioremediation techniques in situ were suggested for the remediation of the contaminated site. The analyzed soil is a very humid clayey silt, with high plasticity, high electrical conductivity, low hydraulic conductivity, low density, large buffering capacity and high cation exchange capacity. The soil is rich in organic matter and poor in nitrogen. The removal of the contaminated soil for ex situ treatment is not advisable in contaminated studied area due to the restrictions imposed by local environmental authority, as well as operational impediments caused by the presence of vegetation and flooded conditions. After the diagnosis a program of laboratory tests was carried out on soil from the location in an electrical cell which was developed for this purpose. The study showed the feasibility of injecting nitrate and ammonium to this kind of soil, though the injection of phosphorous did not prove to be successful. It is recommended to control variations changes in pH, caused by the application of electrokinesis, in order not to harm the biodegradation process.     

Toxicity of parked motor vehicle indoor air

The interior of motor vehicles is made of a wide variety of synthetic materials, which emit volatile organic compounds (VOC). We tested the health effects of emissions from vehicles exposed to "parked in sunshine" conditions. A new and a 3 year old vehicle with identical interior were exposed to 14 000 W of light. Indoor air was analyzed by GC-MS. Toxicity of extracts of indoor air was assayed in human primary keratinocytes, human lung epithelial A549 cell line, and Chinese hamster V79 lung fibroblasts. In addition, toxicity after metabolic activation by CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, and CYP2E1 was assayed. The effect on type I allergic reaction (IgE-mediated immune response), type IV allergic reaction (T-cell mediated immune response), and irritative potential was evaluated also. A total of 10.9 and 1.2 mg/m(3) VOC were found in new and used motor vehicle indoor air, respectively. The major compounds in the new vehicle were o,m,p-xylenes, C3 and C4-alkylbenzenes, dodecane, tridecane, and methylpyrrolidinone. In the used vehicle they were acetone, methylpyrrolidinone, methylcyclohexane, acetaldehyde, o,m,p-xylenes, ethylhexanol, and toluene. No toxicity was observed in any cell line with or without metabolic activation. Neither did we find an effect on type IV sensitization or an irritative potential. A slight but statistically significant aggravating effect on IgE-mediated immune response of only the new vehicle indoor air was determined (p < 0.05). The IgE-response modulating effect of indoor air might be relevant for atopic individuals. Else no direct toxicity, no toxicity after metabolic activation by cytochrome P450, and no irritative or type IV sensitizing potential of motor vehicle indoor air were found, neither from the new nor used vehicle. Our investigations indicated no apparent health hazard of parked motor vehicle indoor air.     

The development of self-assembled liquid crystal display alignment layers

From simple pocket calculators to mobile telephones and liquid crystal display (LCD)-TV, over the past few decades, devices based on LCD technology have proliferated and can now be found in all conceivable aspects of everyday life. Although used in cutting-edge technology, it is surprising that a vital part in the construction of such displays, namely the alignment layer, relies essentially on a mechanical rubbing process, invented almost 100 years ago. In this paper efforts to develop alignment layers (also called command layers) by processes other than rubbing, namely self-assembly of molecular and macromolecular components will be discussed. Two topics will be presented: (i) tuneable command layers formed by stepwise assembling of siloxane oligomers and phthalocyanine dyes on indium tin oxide surfaces and (ii) command layers formed by self-assembly of porphyrin trimers. The potential use of these layers in sensor devices will also be mentioned.     

High‐rate deposition of epitaxial layers for efficient low‐temperature thin film epitaxial silicon solar cells

Low–temperature deposition of Si for thin‐film solar cells has previously been hampered by low deposition rates and low material quality, usually reflected by a low open‐circuit voltage of these solar cells. In contrast, ion‐assisted deposition produces Si films with a minority‐carrier diffusion length of 40 μm, obtained at a record deposition rate of 0.8 μm/min and a deposition temperature of 650°C with a prebake at 810°C. A thin‐film Si solar cell with a 20‐μm‐thick epitaxial layer achieves an open‐circuit voltage of 622 mV and a conversion efficiency of 12.7% without any light trapping structures and without high‐temperature solar cell process steps. Copyright © 2001 John Wiley & Sons, Ltd.     

Heterogeneous polymerization of ethene with metallocene catalysts. A comparison of poly(organosiloxane) microgels and silica as support materials for MAO‐type cocatalysts

Zirconocene dichloride and bis(n‐butylcyclopentadienyl)zirconium dichloride are used as catalyst precursors for the heterogeneous polymerization of ethene. A methyl‐substituted microgel as support material for heterogeneous cocatalysts on the basis of MAO is compared with different commercially available silica‐supported cocatalysts. The catalyst performances and the properties of the obtained polyethenes show considerable differences. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 613–617, 2001     

Verfahren zur Konditionierung von Rohgasen — Teil 1: Konditionierung durch elektrische Maßnahmen

The operating performance of plant for removal of particulates from gases can be positively influenced by crude gas conditioning and other additive measures. These processes involved introduction of additional material or additional energy into the plant. Set goals are the reduction of particle emissions, reduction of operating costs, adaptation to new boundary conditions, or the opening of new applications for the separators concerned. In the first of three surveys, conditioning by electrical means is considered. An account of the principles of electrically induced agglomeration is followed by a presentation and discussion of the possibilities and consequences of electrical effects applied to filtering separators, inertial separators, and wet separators. Wherever possible, points of practical relevance are also evaluated.