70 research outputs found

    In-situ and Remote Sensing Networks for Environmental Monitoring and Global Assessment of Leptospirosis Outbreaks

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    AbstractLeptospirosis is a disease that affects human population and can claim many victims with large outbreaks associated with natural disasters. This work focuses on the technological aspects for inexpensive climate monitoring techniques based on ground and satellite sensors for obtaining information prior to disease outbreaks in under-developed regions and on water-quality sensors that can lead to radical changes in our ability to detect and abate this disease. The remote deployment of such sensors in areas where outbreaks can occur can help in enhancingin real-time the spatial and temporal resolution of information and allows unattended operation that will be particularly useful for monitoring under extreme climate events. Such types of monitoring advancements, when coupled with regular geographical, population and habitat monitoring can assess the hazards and risks to local population prior to a disease outbreak. Then in the eventual aftermath, it can assist in identification of affected geographical locations where abatement solutions will be required, and eventually in the assessment of the effectiveness of control measures. This work explores recent releases of open global observation data and a range of in-situ environmental monitoring tools of increasing complexity for measuring several parameters andfor detecting contaminants and pathogens that were previously irresolvable due to the high degree of complexityinthe diagnosis of this disease

    High-temperature ceramic coatings used in aero engine environments

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    This paper reviews the role of ceramic coatings technology in the hot sections of modern gas turbine engines by contrasting the role of surface engineering and coatings away from secondary reliance (i.e. the coating extending the life of the component and when the coating is lost or fails there is still an appreciable remnant life of the component) to prime reliance where the failure of the coating would result in a rapid failure of the component. To illustrate this change in design philosophy, the coating systems deployed in the HP turbine module in both shrouded and unshrouded configurations are discussed by comparing the performance of first and second generation coating systems

    Application of nanoscale zero valent iron (NZVI) for groundwater remediation in Europe

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    Purpose: Nanoscale zero valent iron (NZVI) is emerging as a new option for the treatment of contaminated soil and groundwater targeting mainly chlorinated organic contaminants (e.g., solvents, pesticides) and inorganic anions or metals. The purpose of this article is to give a short overview of the practical experience with NZVI applications in Europe and to present a comparison to the situation in the USA. Furthermore, the reasons for the difference in technology use are discussed. Method: The results in this article are based on an extensive literature review and structured discussions in an expert workshop with experts from Europe and the USA. The evaluation of the experiences was based on a SWOT (strength, weakness, opportunity, threat) analysis. Result: There are significant differences in the extent and type of technology used between NZVI applications in Europe and the USA. In Europe, only three full-scale remediations with NZVI have been carried out so far, while NZVI is an established treatment method in the USA. Bimetallic particles and emulsified NZVI, which are extensively used in the USA, have not yet been applied in Europe. Economic constraints and the precautionary attitude in Europe raise questions regarding whether NZVI is a cost-effective method for aquifer remediation. Challenges to the commercialization of NZVI include mainly non-technical aspects such as the possibility of a public backlash, the fact that the technology is largely unknown to consultants, governments and site owners as well as the lack of long-term experiences. Conclusion: Despite these concerns, the results of the current field applications with respect to contaminant reduction are promising, and no major adverse impacts on the environment have been reported so far. It is thus expected that these trials will contribute to promoting the technology in Europ

    A new spallation mechanism of thermal barrier coatings and a generalized mechanical model

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    Multilayer thermal barrier coating (TBC) systems typically consist of three layers of materials: A thermal barrier top coat (TC), a thermally-grown oxide (TGO), and a bond coat (BC) in addition to the substrate. Local strain energy concentrations, called ‘pockets of energy concentration (PECs)’ in this work, often occur around the interface between the TGO and the BC. They have various causes, including local phase changes, and non-uniform creep and plastic relaxation. It is discovered that both PECs and buckling drive the spallation of a TBC in a new spallation mechanism. A PEC-based mechanical model is developed that describes, explains and predicts how blisters nucleate in a TBC under constant biaxial compressive residual stress, steadily and then unsteadily grow, and finally spall off. Two conditions are established for the occurrence of TBC spallation, which depend on the compressive residual strain energy density in the TC and the TGO, and the interface fracture toughness. Experimental validation of the model was performed using aircraft jet engine turbine blades with electron beam physical vapor deposition (EBPVD) TBCs. The predictions from the developed PEC-based mechanical model for the radii of spallation in the TBC are in a good agreement with experiment results

    Spontaneous formation and morphology of telephone cord blisters in thin films: the Ω formulae

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    Telephone cord blisters (TCBs) are frequently observed in film/substrate material systems. They nucleate and propagate forward with wavy boundaries between the film and the substrate. The current study views the problem from a completely new angle: It is discovered that the spontaneous formation and morphology of TCBs in thin films under biaxial compressive residual stresses can be accurately explained and determined by assuming the existence of a pocket of energy concentration (PEC) instead of the existence of a separation of critical size. For the first time, completely-analytical formulae—the ‘Ω formulae’—are derived for the two local morphology parameters of TCBs of any shape, that is, width and height, and for the two global morphology parameters of TCBs of sinusoidal shape, that is, the wavelength and transverse amplitude. Mechanical conditions are also given for the first time for the formation of TCBs. Predictions for the four morphology parameters of the developed theory agree very well with extensive experimental results. In addition, by reversing the calculation, the residual stress and the film/substrate interface fracture toughness are also accurately determined from measurements of the TCB morphology parameters

    Epoxy composite dusts with and without carbon nanotubes cause similar pulmonary responses, but differences in liver histology in mice following pulmonary deposition

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    Inorganic chemical composition given as elemental weight% measured by standardless WDXRF. The three epoxy materials were measured as solid disks (4 cm in diameter, 1 cm high). For comparison, the results for CNT powder, previously published in [25], were added to the figure. Displayed axis 99.7 – 100 %. (PPTX 71 kb

    MWCNTs of different physicochemical properties cause similar inflammatory responses, but differences in transcriptional and histological markers of fibrosis in mouse lungs

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    Multi-walled carbon nanotubes (MWCNTs) are extensively produced and used in composite materials and electronic applications, thus increasing risk of worker and consumer exposure. MWCNTs are an inhomogeneous group of nanomaterials that come in various lengths, shapes and with different metal contaminations, which makes hazard evaluation difficult. However, several studies suggest that length plays an important role in the toxicity induced by MWCNTs. How the length influences toxicity at the molecular level is yet to be characterized. Female C57BL/6 mice were exposed by single intratracheal instillation to 18, 54 or 162 µg/mouse of a short MWCNT (NRCWE-026, 847±102 nm in length) or long MWCNT (NM-401, 4048±366 nm in length). The two MWCNTs were extensively characterized. Lung tissues were harvested 24 h, 3 d and 28 d after exposure. We employed DNA microarrays, bronchoalveolar lavage fluid analysis, comet assay and dichlorodihydrofluorescein assay in order to profile the pulmonary responses. Bioinformatics tools were then applied to compare and contrast the expression profiles and to build a length dependent property-response matrix for gene-by-gene comparison. The toxicogenomic analysis of the global mRNA changes after exposure to the short, entangled NRCWE-026 or the longer, stiffer NM-401 showed high degree of similarities. The toxicity of both MWCNTs was driven by strong inflammatory and acute phase responses, which peaked at day 3 and was observed both in bronchoalveolar lavage cell influx and in gene expression profiles. The inflammatory response was sustained at post-exposure day 28. Also, at the sub-chronic level, we identified a sub-set of 14 fibrosis related genes that were uniquely differentially regulated after exposure to NM-401. Acellular ROS production occurred almost exclusively with NRCWE-026, however the longer NM-401 induced in vivo DNA strand breaks and differential regulation of genes involved in free radical scavenging more readily than NRCWE-026. Our results indicate that the global mRNA response after exposure to MWCNTs is length independent at the acute time points, but that fibrosis may be length dependent sub-chronic end point.JRC.H.6-Digital Earth and Reference Dat

    Nanostructured Materials for Environmental Improvement by Monitoring, Remediation and Pollution Prevention

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    Nanotechnology holds promise for improving the environment, in reducing waste and our dependence on non-renewable natural resources, and for cleaning up pollution. Detection and measurement of pollution is a necessary step towards initiating remedial action and nanotechnology is providing essential components for the development of improved systems for environmental monitoring. Advances in sensor and biochip technology are being applied to provide more sensitive detection techniques for air and water quality monitoring. New synthesis methods for efficient metal oxide nanocatalysts can help reduce pollution due to industrial and transport emissions. Chemical activity is dependent on the crystal and surface structures as well as the constituent elements, so precise control at the nanoscale during synthesis is a key factor in improving performance. The photocatalytic properties of titanium dioxide nanoparticles can be exploited to produce ¿self-cleaning¿ architectural coatings that are able to degrade volatile organic compounds, nitrogen oxides and other pollutants into less toxic species. Filtration and purification plants used to treat drinking water and wastewater are generally only partly successful due to the relative inefficiency of the active materials. Due to their greater specific surface area, iron nanoparticles are significantly more effective filtration media than larger particles of the same material. A range of environmental nanotechnologies are already close to market and, once performance and safety have been verified in the field, have potential for very rapid growth.JRC.H-Institute for environment and sustainability (Ispra

    Necesidades de Investigation en Nanotecnologia Biomedica para el Desarrollo de las Regulaciones de Control - Biomedical Nanotechnology and Research Needs in Support of Regulation

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    It is expected that the application of biomedical nanotechnology will lead to progress in medical science, particularly in the areas of disease diagnosis, bio-compatible materials and drug delivery systems. In vitro diagnostic techniques employing biosensors and DNA biochips are now available. Advances in biomedical engineering include biomimetic nanostructures for implants and tissue engineering techniques that will allow, potentially, the growth of artificial organs and the regeneration of damaged nerve tissue. Therapeutic systems using nanopowders and nanotubes for drug delivery and anticancer drugs targeted at tumour cells are under development. The convergence of the physical and biological sciences via nanotechnology can be expected to transform medicine and healthcare. There is concern however regarding the risks of adverse ecological and health effects due to nanoparticles dispersed in the environment and in the human body. Public acceptance of nanotechnology is likely to be strongly influenced by the perception of the associated risks. Modifications to the regulatory framework may therefore be required to guarantee the safe implementation of nanotechnology in healthcare applications. The adoption of a precautionary approach is recommended, together with the use of reliable scientific data to determine the true extent of the risks, and some critical research needs are identified.JRC.H-Institute for environment and sustainability (Ispra
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