Fatigue is a major issue concerning the use of aluminium composites in structural applications. Fatigue leads to weakening of material majorly due to the strain bands formed in the material when it is subjected to rep...Fatigue is a major issue concerning the use of aluminium composites in structural applications. Fatigue leads to weakening of material majorly due to the strain bands formed in the material when it is subjected to repeated loading;the damage that occurs due to fatigue is a progressive and localized one. The fatigue may occur at a stress limit much lesser than the ultimate stress limit of the composite specimen. Henceforth in the current work, fatigue behaviour of silicon carbide and fly ash dispersion strengthened high performance hybrid Al 5083 metal matrix composites are evaluated. The main purpose of fatigue characterisation is to distinctly evaluate the life cycle of components that are fabricated from metal matrix composites and eventually develop a framework model for the significant study of fatigue strength of the structure with persistent striations all along the interstitials of aluminium- silicon carbide-fly ash interfaces. Fatigue is a stochastic process rather than a deterministic one that gives a considerable scatter, even among samples of similar composition with the tests carried out in some of the critically controlled environments. Hence there is a need for statistical validation of the results to authenticate the data collected. Thus in the current work, analysis of variance is carried out to establish the authenticity of the results and validate them. The results and plots are presented with suitable rationale and inferences.展开更多
A functionalized silicon nanowire field-effect transistor （SiNW FET） was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method wi...A functionalized silicon nanowire field-effect transistor （SiNW FET） was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method with the ability to provide specific and reliable data. The device was designed and fabricated by indented ash trimming via shallow anisotropic etching. The approach is a simple and low-cost technique that is compatible with the current commercial semiconductor standard CMOS process without an expensive deep reactive ion etcher. Specific electric changes were observed for DNA sensing when the nanowire surface was modified with a complementary captured DNA probe and target DNA through an organic linker （--OCH2CH3） using organofunctional alkoxysilanes （3-aminopropyl） triethoxysilane （APTES）. With this surface modification, a single specific target molecule can be detected. The simplicity of the sensing domain makes it feasible to miniaturize it for the development of a cancer detection kit, facilitating its use in both clinical and non-clinical environments to allow non-expert interpretation. With its novel electric response and potential for mass commercial fabrication, this biosensor can be developed to become a portable/point of care biosensor for both field and diagnostic applications.展开更多
Geopolymers are three-dimensional aluminosilicates formed in a short time at low temperature by geopolymerization. In this pa-per, alkali-activated foam geopolymers were fabricated from circulating fluidized bed fly a...Geopolymers are three-dimensional aluminosilicates formed in a short time at low temperature by geopolymerization. In this pa-per, alkali-activated foam geopolymers were fabricated from circulating fluidized bed fly ash （CFA）, and the effect of SiO2/Na2O mole ratio （0.91-1.68） on their properties was studied. Geopolymerization products were characterized by mechanical testing, scanning electron mi-croscopy （SEM）, energy-dispersive X-ray spectroscopy （EDX）, and X-ray diffraction （XRD）. The results show that SiO2/Na2O mole ratio plays an important role in the mechanical and morphological characteristics of geopolymers. Foam samples prepared in 28 d with a SiO2/Na2O mole ratio of 1.42 exhibit the greatest compressive strength of 2.52 MPa. Morphological analysis reveals that these foam geo-polymers appear the relatively optimized pore structure and distribution, which are beneficial to the structure stability. Moreover, a combina-tion of the Si/Al atomic ratio ranging between 1.47 and 1.94 with the Na/Al atomic ratio of about 1 produces the samples with high strength.展开更多
The effect of mechanical and tribological behaviour of aluminium alloy(Al-Si10-Mg) with sugarcane bagasse ash and silicon carbide reinforced metal matrix composites were investigated. Al-Si10-Mg alloy reinforced with ...The effect of mechanical and tribological behaviour of aluminium alloy(Al-Si10-Mg) with sugarcane bagasse ash and silicon carbide reinforced metal matrix composites were investigated. Al-Si10-Mg alloy reinforced with 9 wt.% of treated sugarcane bagasse ash particles of size(< 75 μm) and 0 wt.%, 3 wt.%, 6 wt.% and 9 wt.% of silicon carbide particles of size(< 25 μm) were fabricated using the stir casting method. Morphological analysis was done using scanning electron microscopy to access the distribution of reinforcement particles in the matrix alloy. Tensile, hardness, and impact strengths were increased with an increase in weight fraction of SiC reinforcement particles in the aluminium alloy, while the ductility was decreased. Pin-on-disc dry sliding wear test was carried out with 10, 20 and 30 N loads with a sliding speed of 10 m·s-1 for a constant time period of 20 min to predict the wear behaviour of the developed composites. Worn surfaces of the wear-tested specimens and fracture morphology structure of the tensile-tested specimens were analysed. Results show that the composites reinforced with sugarcane bagasse ash and silicon carbide particles exhibit superior wear resistance.展开更多
文摘Fatigue is a major issue concerning the use of aluminium composites in structural applications. Fatigue leads to weakening of material majorly due to the strain bands formed in the material when it is subjected to repeated loading;the damage that occurs due to fatigue is a progressive and localized one. The fatigue may occur at a stress limit much lesser than the ultimate stress limit of the composite specimen. Henceforth in the current work, fatigue behaviour of silicon carbide and fly ash dispersion strengthened high performance hybrid Al 5083 metal matrix composites are evaluated. The main purpose of fatigue characterisation is to distinctly evaluate the life cycle of components that are fabricated from metal matrix composites and eventually develop a framework model for the significant study of fatigue strength of the structure with persistent striations all along the interstitials of aluminium- silicon carbide-fly ash interfaces. Fatigue is a stochastic process rather than a deterministic one that gives a considerable scatter, even among samples of similar composition with the tests carried out in some of the critically controlled environments. Hence there is a need for statistical validation of the results to authenticate the data collected. Thus in the current work, analysis of variance is carried out to establish the authenticity of the results and validate them. The results and plots are presented with suitable rationale and inferences.
文摘A functionalized silicon nanowire field-effect transistor （SiNW FET） was fabricated to detect single molecules in the pM range to detect disease at the early stage with a sensitive, robust, and inexpensive method with the ability to provide specific and reliable data. The device was designed and fabricated by indented ash trimming via shallow anisotropic etching. The approach is a simple and low-cost technique that is compatible with the current commercial semiconductor standard CMOS process without an expensive deep reactive ion etcher. Specific electric changes were observed for DNA sensing when the nanowire surface was modified with a complementary captured DNA probe and target DNA through an organic linker （--OCH2CH3） using organofunctional alkoxysilanes （3-aminopropyl） triethoxysilane （APTES）. With this surface modification, a single specific target molecule can be detected. The simplicity of the sensing domain makes it feasible to miniaturize it for the development of a cancer detection kit, facilitating its use in both clinical and non-clinical environments to allow non-expert interpretation. With its novel electric response and potential for mass commercial fabrication, this biosensor can be developed to become a portable/point of care biosensor for both field and diagnostic applications.
基金financially supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20120023110011)the Fundamental Research Funds for the Central Universities of China(Nos.2009KH09 and 2009QH02)
文摘Geopolymers are three-dimensional aluminosilicates formed in a short time at low temperature by geopolymerization. In this pa-per, alkali-activated foam geopolymers were fabricated from circulating fluidized bed fly ash （CFA）, and the effect of SiO2/Na2O mole ratio （0.91-1.68） on their properties was studied. Geopolymerization products were characterized by mechanical testing, scanning electron mi-croscopy （SEM）, energy-dispersive X-ray spectroscopy （EDX）, and X-ray diffraction （XRD）. The results show that SiO2/Na2O mole ratio plays an important role in the mechanical and morphological characteristics of geopolymers. Foam samples prepared in 28 d with a SiO2/Na2O mole ratio of 1.42 exhibit the greatest compressive strength of 2.52 MPa. Morphological analysis reveals that these foam geo-polymers appear the relatively optimized pore structure and distribution, which are beneficial to the structure stability. Moreover, a combina-tion of the Si/Al atomic ratio ranging between 1.47 and 1.94 with the Na/Al atomic ratio of about 1 produces the samples with high strength.
文摘The effect of mechanical and tribological behaviour of aluminium alloy(Al-Si10-Mg) with sugarcane bagasse ash and silicon carbide reinforced metal matrix composites were investigated. Al-Si10-Mg alloy reinforced with 9 wt.% of treated sugarcane bagasse ash particles of size(< 75 μm) and 0 wt.%, 3 wt.%, 6 wt.% and 9 wt.% of silicon carbide particles of size(< 25 μm) were fabricated using the stir casting method. Morphological analysis was done using scanning electron microscopy to access the distribution of reinforcement particles in the matrix alloy. Tensile, hardness, and impact strengths were increased with an increase in weight fraction of SiC reinforcement particles in the aluminium alloy, while the ductility was decreased. Pin-on-disc dry sliding wear test was carried out with 10, 20 and 30 N loads with a sliding speed of 10 m·s-1 for a constant time period of 20 min to predict the wear behaviour of the developed composites. Worn surfaces of the wear-tested specimens and fracture morphology structure of the tensile-tested specimens were analysed. Results show that the composites reinforced with sugarcane bagasse ash and silicon carbide particles exhibit superior wear resistance.
