Search results for "Moisture"
showing 10 items of 290 documents
Carbon Fiber Composites Cured by γ-Radiation-Induced Polymerization of an Epoxy Resin Matrix
2008
The use of ionizing radiation in order to initiate polymerization of suitable monomers has found increased interest in the last two decades due to its several advantages. In this work, carbon fiber composites through gamma radiation polymerization of epoxy matrices have been produced for aerospace and advanced automotive applications. Composite samples were produced by irradiation at room temperature using different radiation doses and, as reference, thermal curing of the same epoxy resin formulations was also carried out. Furthermore, some irradiated samples were subjected to postirradiation thermal curing to complete the polymerization reactions. The properties of the cured materials were…
Study the effects of moisture content on the electrical properties of technical textiles by impedance spectroscopy
2012
Application of metal coatings for the functionalization of technical fibres and fabrics faced with influence of moisture on functional properties, e.g., the impedance of the metal coated K-glass fabrics have strong dependence of content absorbed water or moisture. The paper devoted to develop methodology for characterisation functional materials based on fabrics and model for interpretation of the electrical impedance spectra to obtained functional characteristics of technical textile fabrics. Model based on analyses of 3D plot of imaginary part of complex modulus spectra versus sample mass. Methodology helps to control content of adsorbed water in fabric and influence of moisture on the fu…
Thermal and moisture adsorption/desorption properties for a selection of vegetal insulation materials
2019
Natural, or ‘green’ insulation materials, have become more popular for the ‘ecologisation’ of construction activities. The ecological aspects for such materials are being widely analysed, but experimental data about their physical properties when installed in building constructions remains lacking. In this study, pressed samples of three locally wild grown agricultural materials – rye, reed, and hemp – are analysed. Thermal conductivity measurements were carried out using the hot plate device. Comparison with widely used mineral insulation materials shows that thermal conductivity for simple pressed materials are roughly three times higher, and are comparable to plywood and cross-laminated …
Role of continuous moisture profile monitoring by inline NIR spectroscopy during fluid bed granulation of an Enalapril formulation
2010
Granulation and tableting are closely related process steps in the supply chain of pharmaceutical products. Even today, these steps are still optimized independently by trial and error. On the framework of a process analytical technology approach, these processes were evaluated in an integrated approach. Enalapril maleate is a low-dose drug substance with poor granulating and tableting behavior. In order to verify how granulation influences tableting properties, different granulation experiments were performed.Granulation experiments with fast spraying rate and fast drying as well as fast spraying rate and slow drying, and also combinations of both were run. The obtained granules were then …
Surface Functionalization of Metal–Organic Framework Crystals with Catechol Coatings for Enhanced Moisture Tolerance
2021
Robust catechol coatings for enhanced moisture tolerance were produced in one step by direct reaction of Hong Kong University of Science and Technology (HKUST) with synthetic catechols. We ascribe the rapid formation of homogeneous coatings around the metal–organic framework particles to the biomimetic catalytic activity of Cu(II) dimers in the external surface of the crystals. Use of fluorinated catechols results in hydrophobic, permeable coatings that protect HKUST from water degradation while retaining close to 100% of its original sorption capacity.
Moisture absorption by epoxy/montmorillonite nanocomposite
2009
The peculiarities of moisture absorption of epoxy–nanoclay composite are estimated in the paper. Second Fick’s law of diffusion was used to predict moisture diffusivity and equilibrium moisture content using accelerated analytical procedure. It was experimentally confirmed that sorption process in NC passes more slowly than in pure epoxy resin, for the highest filler content diffusivity reduces about half of diffusivity as for epoxy resin. The deviation from mixture rule was obtained for the equilibrium moisture content and the estimation of interphase content in composite was undertaken. It was determined that the higher content of interphase consistently leads to greater moisture absorpti…
Electrochemical impedance and moisture content of glass fabric
2012
The glass fiber fabrics have application at the wet conditions. Impedance measurements of sodium alumosilicate glass fabric in dependence on its moisture content are presented. The impact of pores of glass fibres and fabric components to electrochemical impedance of fabric are investigated and discussed.
Moisture Effects on Patch Bonded Composite Repairs
2016
The present work investigated the effects of moisture absorption on the residual tensile strength of unnotched, notched and double-patch repaired carbon/epoxy composites. Patches were bonded to the parent plate using Araldite2015 adhesive. Specimens were aged in demineralised water at 70°C and tested at moisture content of 0% (dry), 3%, 6% and 7%. Results showed that upon ageing, a maximum of 11% and 17% of strength reduction was found in unnotched and repaired specimens, respectively. On the contrary, a maximum of 15% increment in strength was observed in notched specimens. In addition, good fits to the experimental data were found using the proposed residual strength model, with the maxim…
Application of metal coatings for functionalization of technical fibers and fabrics
2011
The metal coatings in combination with sonochemical and leaching processes are used for nanostructuring and functionalization of glass, flax and hemp fabrics. The leaching is used for nanostructuring sodium alumosilicate K-glass fabrics to obtained silica like fibre with nanoporous structure on surface and in volume. The natural fibres as well as fabrics themselves are porous media. The porous media adsorbs water and content of moisture in fabrics have to be controlled. The metal-coated fabric characterization is an actual problem. Application of metal coatings for the functionalization of technical fibres and fabrics faced with influence of moisture on functional properties, e.g., the impe…
Moisture ingress in photovoltaic modules: A review
2021
Abstract Moisture ingress in photovoltaic (PV) modules is the core of most degradation mechanisms that lead to PV module power degradation. Moisture in EVA encapsulant can lead to metal grids corrosion, delamination and discolouration of encapsulants, potential induced degradation, optical and adhesion losses. The present work is a review of literature on the causes, effects, detection, and mitigation techniques of moisture ingress in PV modules. Literature highlights on determining the diffusivity, solubility, and permeability of polymeric components of PV modules via water vapour transmission rate tests, gravimetric, and immersion methods, have been presented. Electroluminescence, photolu…