Search results for "Composite"
showing 10 items of 4584 documents
Preparation and Characterization of Polyolefin-Based Nanocomposite Blown Films for Agricultural Applications
2009
These kinds of filmshave,asaprimaryaim,tocreateafavorablemicro-climateto accelerate the plant growth.Thematerialsfortheseapplicationsmustpossessseveralspecificandpeculiarcharacteristics,suchastheabilitytobeshaped into films (even with wide dimensions and largethickness ranges), good deformability and tear resistancetogetherwithasufficientrigidity,transparencyforUVandIR radiation in particular regions of the spectrum, a goodresistance to photo-oxidative phenomena and for someapplications to provide a barrier for certain gases.Moreover, an important property requested for thematerials used for greenhouse covering is the capabilityto diffuse the light. In fact, according to some studies,diffused l…
Surface structure determination by SEM image processing and electrochemical impedance of graphite+polyethylene composite electrodes
2004
Abstract The electrochemical impedance behaviour of heterogeneous or/and rough electrodes has usually been associated with some geometrical parameters of the surface structure or to a statistical description of the surface properties. An experimental method for sample preparation of graphite + polyethylene composite electrodes based on plasma etching is proposed. After plasma etching, the statistical properties of the electrode, such as the graphite particle size distribution and fractional coverage are measured from scanning electron microscopy pictures using image processing software. The statistical information obtained for the surface is combined with impedance equations of independent …
Plasma Functionalization of Multiwalled Carbon Nanotubes and Their Use in the Preparation of Nylon 6-Based Nanohybrids
2012
The possibility to obtain carbon nanotubes (CNT)/polyamide 6 composites with excellent mechanical properties in a simple, industrially scalable way is investigated. Commercial CNTs are treated by plasma while changing some key parameters (exposure time, plasma power, type of gas) in order to optimize the process and to achieve a sufficient degree of functionalization. The treated samples are characterized by Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The most interesting samples are selected to be used as reinforcing fillers, in different concentrations, in a polyamide 6 matrix. The mechanical tests show a dramatic increase of both tens…
Au-ZnO Nanocomposite Films for Plasmonic Photocatalysis
2015
Nanocomposites based on plasmonic nanoparticles and metal-oxide semiconductors are emerging as promising materials for conversion of solar energy into chemical energy. In this work, a Au–ZnO nanocomposite film with notably enhanced photocatalytic activity is successfully prepared by a single-step process. Both ZnO and Au nanoparticles are synthesized in situ during baking of the film spin-coated from a solution of Zn(CH3COO)2 and HAuCl4. Furthermore, it is shown that this precursor solution can be formulated as a nanoink for the generation of micropatterns by microplotter printing, opening the way for the miniaturization of devices with enhanced properties for photocatalysis, optoelectronic…
Influence of material characteristics on plastomechanics of the fsw process for T-joints
2009
Abstract The potential of friction stir welding (FSW) has thoroughly been investigated by several authors, however their focus has primarily been on butt joints. T-joints are of paramount interest for transportation industries especially due to their capacity to straighten panels. Welding of T-joints is very challenging due to thin walls, poor location of the rib–web interface and the requirements for corner-fillets. This paper investigates FSW of T-joints of two popular aluminum alloys, i.e. 2024-T4 and 6082-T6, and the role played by the material characteristics on joining. First, an experimental study is carried out with specially designed fixture to determine the effect of process condi…
Modeling of the Plastic Characteristics of AA6082 for the Friction Stir Welding Process
2015
Focus of this paper is to model the plastic forming behavior of AA6082, in order to develop the numerical FE analysis of the friction stir welding processes and the simulation of subsequent forming processes. During the friction stir welding process, the temperatures reached are until 500 °C and have a fundamental role for the correct performance of the process so the material data has to show a temperature dependency. Because of the tool rotation a strain rate sensitivity of the material has to be respected as well. In this context, the general material characteristics of AA6082 were first identified for different stress states. For the uniaxial state the standard PuD-Al used in the automo…
Microstructural evolution and growth of crystallite size of mullite during thermal transformation of kyanite
1997
Abstract The microstructural evolution of mullite during the thermal transformation of kyanite has been studied in the temperature range 1200–1600 °C. The shape and size of the grains were analysed by means of SEM-EDS while crystallite size evolution was studied by X-ray line profile analyses. The results obtained showed that total transformation of kyanite to mullite takes place between 1350 and 1400 °C. At temperatures below 1350 °C needle-like mullite grains are always produced. At higher temperatures the mullite grains reveal rounded end platelet morphology. Evolution from needle-like to platelet shape was correlated with the X-ray data.
Quarry limestone dust as fine aggregate for concrete
2018
In quarrying activities, rock is extracted and transformed into aggregate of various sizes for civil engineering applications. In this process waste fine aggregates (dust waste) are generated. The disposal of this type of waste is a further cost in the extraction process, but also a possible cause of environmental pollution (e.g. leaching into water reserves, atmospheric pollution as a result of small particles causing respiratory diseases or deposited on plants disrupting photosynthesis, affecting aquatic habitats, etc.). A strategy for the effective recycling of quarry dust does not only reduce waste generation and disposal, but also addresses protection of the environment. The Italian qu…
Multitemporal fusion of Landsat/TM and ENVISAT/MERIS for crop monitoring
2013
Abstract Monitoring Earth dynamics using current and future satellites is one of the most important objectives of the remote sensing community. The exploitation of image time series from sensors with different characteristics provides new opportunities to increase the knowledge about environmental changes and to support many operational applications. This paper presents an image fusion approach based on multiresolution and multisensor regularized spatial unmixing. The approach yields a composite image with the spatial resolution of the high spatial resolution image while retaining the spectral and temporal characteristics of the medium spatial resolution image. The approach is tested using …
Early modern state formation in the margins? A review of early modern popular politics and limited royal power in the Polish-Lithuanian Commonwealth …
2017
The traditional historiography of early modern state-building has usually followed the western European paradigm of historiography, the usual models being France, England, Brandenburg-Prussia and Sweden. Regions that do not follow this paradigm have simply been left out and labeled “backward” or as “lagging behind”. In this literary review, our focus is on two different and rather surprising cases of early modern state formation: the Polish-Lithuanian Commonwealth and the Spanish colonial empire in Latin America. By following the scholarship on these two large conglomerates, we focus on two scholarly concepts: the idea of early modern realms as composite/conglomerate states, and state forma…