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composites, ceramic matrix composites, carbon/carbon composites, and polymer matrix composites (PMCs) [ 1 – 7 ]. The main advantages of PMCs are their relatively low density and established processing methods. PMCs containing metal or ceramic particles are

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Abstract  

A sensitive method to characterize the thermomechanical behaviour of fiber reinforced composites is the dynamic mechanical thermoanalysis (DMTA) method. A Round-Robin-test with five different institutes was conducted to determine the role of the fiber orientation, processing conditions, test apparatus, the mode of loading, and the matrix materials on the determination of the glass transition temperature (Tg). The result shows that the DMTA is a suitable method to analyze Tg of long fiber composites. However, some major problems have to be taken into consideration: - A direct comparison of results from different DMTA-systems is not possible - The real temperatures in the specimens deviate from the temperatures displayed by the DMTA measuring system - There is no clear and common evaluation method for the glass transition temperature.

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of EP, the fiber reinforced epoxy composite is easily flammable and its development and application in many fields is limited. Some literature focus on the flame retardancy of glass or carbon fiber reinforced epoxy composites using non-halogen flame

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Two improved tropical maize composites, TZL COMP3 and TZL COMP4; representing complementary heterotic pools have been subjected to four cycles of reciprocal recurrent selection (RRS) for two decades to enhance varietal cross performance. The objectives of this study were to evaluate the effect of selection on genetic gain in heterosis for grain yield and other agronomic traits of these composites. Ten parental populations representing the C0 to C4 of each composite and their crosses plus a varietal check were evaluated in a trial at eight environments in Nigeria. Grain yield of the varietal crosses increased with selection by 3.1% cycle–1. Mean grain yields of the C4 × C4 varietal cross exceeded that of a popular improved reference variety by 23%. Selection also reduced anthesis-silking interval, improved ear characteristics, phenotypic appeal and resistance to foliar diseases. Mid-parent heterosis (MPH) increased from 4% at C0 × C0 to 24% at C4 × C4. The average rate of genetic gain in heterosis for grain yield in population crosses was 3.1% possibly because of presence of non-additive gene effects. The results of our study present the potential usefulness of the advanced selection cycle as sources of diverse inbred lines with improved combining ability as well as improved varietal crosses that can be multiplied and deployed in areas with limited market access.

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Introduction Polymerization shrinkage remains a challenge, and one of the leading causes of secondary caries around resin-based composites (RBCs), which is the primary season for the clinical replacement of RBCs [ 1

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Introduction PP based composites have a wide ranges of applications in many engineering and industrial atmosphere. At higher temperatures, semicrystalline polymers in polymer-filler composites show different thermal and

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Ricles J. M., Popov E. P. Experiments on eccentrically braced frames with composite floors , Earthquake Engineering Research Center, University of California, Berkeley, California, 1987

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Introduction In many industrial applications, components are required to work in extremely hard conditions, particularly at very high temperatures for long times. For these applications, new ceramic matrix composites have been

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Journal of Thermal Analysis and Calorimetry
Authors: A. Danch, W. Osoba, D. Chrobak, G. Nowaczyk, and S. Jurga

Abstract  

The study presents properties of polyethylene commercial products with special attention to properties of a ‘semi-ordered’ amorphous phase. Although, one can hardly prove the existence of such an interphase, the results description based on the idea of coexistence of two amorphous fractions (‘real’ and ‘semi-ordered’) in one system gives a broader understanding of the relationship between product history and morphology of the resultant engineering products. Their supermolecular structures were explored using positron annihilation lifetime spectroscopy (PALS), calorimetry (DSC) and mechanical spectroscopy in a tensile and a torsion mode (DMTA). The stability of these structures is also discussed based on a simple statistical analysis of the thermodynamic and structural parameters. The study exhibited that chalk did not disturb too much the crystalline domains of PE-LD whereas it influenced the interphase. Mechanical study showed that such a product is not stable during long time storage. The comparison with previous results, obtained for PE-carbon black composites, revealed differences in the morphologies and the αc relaxations of PE chains, observed in the composites including various fillers.

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that acts as a heat shield for composites. Consistent with this mechanism, the flame retardancy was found to improve with better dispersion and a higher interface area (aspect ratio) of the nanotubes at desired loading. However, the major hurdle

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