M. Bassyouni

Assessment and Analysis of Wind Power Resource Using Weibull Parameters

In this study, wind data of eleven years (2002–2012) has been used to determine wind characteristics of Saudi Arabian city Jeddah. These characteristics include the daily, monthly and annual wind speed, wind probability density distribution, shape (k) and scale (c) parameters at 10 m height. The analysis revealed that yearly values of k ranged from 1.398 to 1.763 with a mean value of 1.590 and values of scale parameter c varied from 3.146 to 4.329 with mean value of 3.95. Furthermore, the results showed that maximum and minimum wind power potential was observed in the month of March and February, respectively. The wind was found to be blowing predominantly from south east direction. It was found that wind potential of the region can be used for small scale off-grid wind applications.

Physico-mechanical properties of chemically treated polypropylene rice straw bio-composites

Rice straw is causing in many countries severe environmental problems in terms of black clouds caused by the incineration process. Hence, among other reasons, the incorporation of ground rice straw as a filler and reinforcement material for polymers is of advantageous. In this study, Egyptian rice straw was used to reinforce commercial polypropylene and laboratory prepared maleic anhydride-grafted PP with the fill grades between 5wt% and 30wt%. Rice straw PP composites show an improved Youngs modulus at increased fill grades, against a decrease in tensile strength. The addition of 1% maleic anhydride per I g of rice straw as a compatibilizing agent caused further amelioration of the fiber/matrix bonding leading to improved mechanical behavior, which was also assessed using scanning electron microscopy. Additional assessments were made via thermographic analysis and density measurements.

Fabrication and thermal characteristics of functionalized carbon nanotubes impregnated polydimethylsiloxane nanocomposites

Multiwalled carbon nanotubes (MWCNTs) were modified to covalently attach the carboxylic moiety with their surfaces. Variant concentrations of functionalized multiwalled carbon nanotubes (F-MWCNTs) were introduced into polydimethylsiloxane (PDMS) adopting solution mixing technique. Fourier transform infrared spectroscopy (FTIR) confirms the carboxy functionalization presence on the surface of the nanotubes. X-ray diffraction (XRD) patterns for both MWCNTs and F-MWCNTs illustrate that the crystallinity does not alter with surface modification of the nanotubes. Experimental results simulated that electrical conductivity of the nanocomposites was augmented with increasing filler concentration in the host matrix. Thermal conductivity and thermal impedance of the nanocomposite specimens were evaluated according to developed methodologies and the accumulative data revealed the nanocomposites thermal transport dependence on the F-MWCNTs doping concentration in the host polymer matrix. Thermal stability enhancement with increasing filler incorporation into the polymer matrix was observed in thermogravimetric/differential thermal analyzer (TG/DTA) contours. Crystallization, glass transition, and melting temperatures were examined using differential scanning calorimeter (DSC) and it was observed that phase transition temperatures of the composite specimens can be tuned by varying the nanotubes to matrix ratio. Scanning electron microscopy and energy dispersive x-ray spectroscopy were carried out to analyze the surface morphology/composition of the fabricated nanocomposites and dispersion of functionalized and pristine MWCNTs in the polymer matrix.

Materials Selection Strategy and Surface Treatment of Polymer Composites for Wind Turbine Blades Fabrication

In the present work the optimal materials selection for wind turbine blades using the Cambridge Engineering Selector (CES) program was carried out. Materials indices were derived, based on the mechanical, physical properties and environmental circumstances. Glass and carbon fibre reinforced plastics (epoxy matrix) showed high materials indices based on combined analysis of power and efficiency, fracture toughness, fatigue and thermal stability. Epoxy-glass fibre (EGF) and epoxy-carbon fibre (ECF) composites were manufactured and investigated. Surface of glass and carbon fibre was chemically modified using gamma-aminopropyltriethoxysilane (Silane A1100) coupling agent. The fibre content was varied between 12 to 70% w/w. It is found that the addition of (Silane A1100) as a compatibilizer caused further amelioration of the fibre/matrix bonding resulting in improved mechanical behaviour, which was also, assessed using scanning electron microscopy. Mechanical properties of treated and untreated epoxy composites were illustrated using CES program. Tensile strength of EGF composites was varied based on fibres surface treatment and loadings. Tensile strength of silane treated EGF (70% wt/wt) increased to 1.46 GPa comparing with 1.38 GPa of untreated EGF. The potential and applications of this class of composite materials promise a significant opportunity for improving structural properties of wind turbine blades.

Effects of Surface Treatment of Ground Rice Husk on the Polyurethane Based on Castor Oil

Polyurethane (PU) elastomer based on castor oil and polymeric diphenylmethane diisocyanate (PMDI) was synthesised with NCO/OH ratio = 2 as a polymeric matrix. Polyurethane was composited with rice husk with average particle size less than 200 μm. Ground rice husk was pretreated by steam and sodium hydroxide solution in order to study and evaluate the effect of different surface treatment methods on the properties of the polyurethane composites. Scanning Electron Microscopy (SEM) was used to investigate dispersion and fracture surfaces of the composites. Mechanical test (hardness), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC), were employed to characterise the developed composite materials in details. Composite polyurethanes based on treated and untreated rice husk showed different physical, chemical and mechanical properties. SEM micrographs of PU-treated rice husk (steam) displayed rice husk tightly embedded in the PU matrix with uniform distribution. The steam treatment increased the interfacial adhesion within the material, which showed a high thermal stability. PU-treated rice husk (sodium hydroxide 10 wt.%) showed poor mechanical properties. Untreated rice husk showed moderate mechanical properties as compared to the preceding cases.

The use of rice straw and husk fibers as reinforcements in composites

Abstract: Rice straw and rice husk fiber are underutilized agricultural residues with potential for use in reinforced polymer composites that would save existing wood and petroleum resources. With some brief description of rice plants and their cultivation, harvesting and milling, this chapter discusses methods of testing the properties of rice straw and rice husk fibers, fiber surface treatments and the use of coupling agents for the integration of fibers into a polymer matrix, the processing of thermoset and thermoplastic composites reinforced by rice straw and rice husk fibers, and the physical and mechanical properties of such composites. Differences in properties between rice straw composites and rice husk composites respectively are described. It is also noted that much research on coupling agents remains to be done.

Synthesis, fabrication and mechanical characterization of reinforced epoxy and polypropylene composites for wind turbine blades

Failure of wind turbine blades usually originates from manufacturing defects or in-service defects. In this study, materials selection for manufacturing of wind turbine blades was carried out based on the mechanical and physical results obtained using the Cambridge Engineering Selector program. Thermoplastic and thermosetting composites were synthesized and processed using injection molding and vacuum assisted resin infusion techniques, respectively. Operating conditions (vacuum pressure and temperature) were optimized. The manufactured samples were tested and evaluated using destructive tests. Tensile and fatigue tests were carried out. Polypropylene random discontinuous glass fiber composites were synthesized and processed using mold injection technique. Epoxy-carbon, glass and carbon/Kevlar hybrid fiber composites were manufactured using vacuum assisted resin infusion technique. Surface morphology was characterized using scanning electron microscope analysis. Tensile strength and fatigue resistance were significantly improved by the presence of E-glass fiber (30 wt%) in polypropylene-glass fiber composites. The experimental results were compared with the Cambridge Engineering selector software database. Epoxy-carbon (carbon fiber fraction is 0.61) and carbon/Kevlar hybrid (fibers fraction is 0.6) composites showed superior mechanical properties. Epoxy/carbon composite can withstand stresses up to 1390 MPa at 106 cycles.

MWCNTS Incorporated Natural Rubber Composites: Thermal Insulation, Phase Transition and Mechanical Properties

The effect of variant concentrations of multiwalled carbon nanotubes (MWCNTs) on the thermal transport, phase transition temperatures, and mechanical properties of polyisoprene rubber have been studied in the present novel research. MWCNTs were incorporated into the natural rubber (NR) using shear mixing techniques. Microscopy results reveal the uniform dispersion of the nanotubes within the polymer matrix. Thermal conductivity and thermal insulation of the fabricated composites were evaluated according to ASTM standards. Thermal transport through the nanocomposite specimens is restricted by the nanotubes network developed within the polymer matrix. Differential scanning calorimetric study elucidates the reduction of crystallization (T c ) and glass transition (T g ) temperatures, while melting temperature (T m ) enhances with increasing the nanotubes concentration in the rubber matrix. A remarkable enhancement in mechanical properties of MWCNT/NR composites was observed with increasing nanotube to matrix ratio. techniques to fabricate nanocomposites for engineering applications, i.e., automobile industry, sports industry, membrane technology, aerospace industry, energy storage and many more. In order to fabricate an affective composite, aspect ratio of the nanotube should not be diminished. The CNTs/polymer nanocomposites have also shown outstanding thermal stability in nitrogen as well as in oxygen atmospheres. Uniformly dispersed nanotubes develop a network in a polymer matrix that restricts the thermal mobility of polymeric chains in the heat atmosphere (3). Polyisoprene rubber (NR) with superb thermal/mechanical properties, oil/hot air ageing and swelling resistance has extensively used in automobile and oil industries. Selection and designing of a composite for a specific application necessitate its thermal transport/endurance data. Evaluation of thermal properties for a polymer nanocomposite has great importance to allocate relevance area of application. This paper reports the novel investigation of thermal impedance, thermal conductivity, thermal composition, heat flow response, glass transition/crystallization/melting temperatures, and specific enthalpies of NR nanocomposites with five diverse loadings of pristine multiwalled carbon nanotubes (MWCNTs).

Materials Selection, Synthesis, and Dielectrical Properties of PVC Nanocomposites

Materials selection process for electrical insulation application was carried out using Cambridge Engineering Selector (CES) program. Melt mixing technique was applied to prepare polyvinyl-chloride- (PVC-) nanofumed silica and nanomontmorillonite clay composites. Surface analysis and particles dispersibility were examined using scanning electron microscope. Dielectrical properties were assessed using Hipot tester. An experimental work for dielectric loss of the nanocomposite materials has been investigated in a frequency range of 10 Hz–50 kHz. The initial results using CES program showed that microparticles of silica and clay can improve electrical insulation properties and modulus of elasticity of PVC. Nano-montmorillonite clay composites were synthesized and characterized. Experimental analyses displayed that trapping properties of matrix are highly modified by the presence of nanofillers. The nanofumed silica and nanoclay particles were dispersed homogenously in PVC up to 10% wt/wt. Dielectric loss tangent constant of PVC-nanoclay composites was decreased successfully from 0.57 to 0.5 at 100 Hz using fillers loading from 1% to 10% wt/wt, respectively. Nano-fumed silica showed a significant influence on the electrical resistivity of PVC by enhancing it up to 1 × 1011 Ohm·m.

The Role of GTL Technology as an Option to Exploit Natural Gas Resources

Large amounts of global sources of remote natural reserves gas are identified along with the main objective to allow energy contained in to be moved economically to the market. The current options that are adopted to export natural gas are basically two:- 1. To liquefy the gas and ship it as LNG (Liquefied Natural Gas). 2. To convert it to bulk petrochemicals in particular methanol or ammonia and other down-stream products. The last approach represents relatively small usage of the gas with limited markets. Chemical conversion before transpor- tation of natural gas to liquid (GTL), using Fisher-Tropsch process offers an attractive alternative to unlock remote sources of natural gas. It is reported to be most promising on the basis of its current level of development and its potential future improvements. The two main components of Fisher-Tropsch process are carefully examined: synthesis gas generation and its subsequent conversion to clean petroleum fuel. Different methods of producing synthesis gas are described. These include: steam re- forming, non catalytic partial oxidation (NCPO), auto thermal reforming (ATR) and combined reforming. Chemical reac- tions underlying the Fisher-Tropsch process are presented with trends of developments in the GTL technology. Commercial applications of GTL technology worldwide are cited, especially in some Arab countries. The positive impact of GTL on the environment is emphasized because of two reasons: 1 st the clean-burning properties of the produced diesel fuels, 2 nd converting natural gas to liquid allows oil producers to utilize the natural gas that would otherwise be flared and pollute the atmosphere.