The ever-increasing demand for light weighted hard materials for transportation industries encouraged researchers to develop composites with excellent mechanical properties which can transform it into more economical ...The ever-increasing demand for light weighted hard materials for transportation industries encouraged researchers to develop composites with excellent mechanical properties which can transform it into more economical and eco-friendly.Reinforcing the metals with carbonaceous nanomaterials are progressively in focus due to their excellent capability to inculcate and tailor the properties of MMCs.In the present research,a hybrid nanocomposite of MWCNT-Graphene-AZ31 Mg alloy has been developed by using variable tool rotation speeds with friction stir processing(FSP).Optimized reinforcement ratio of 1.6%vol.MWCNT and 0.3%vol.of graphene have been used with variable tool rotation speeds,whereas other processing parameters are kept constant.The developed specimens were investigated using standard testing equipment for evaluating and comparing the mechanical properties on the basis of the microstructure of the processing regions and their morphological analysis,according to the ASTM standards.The obtained results revealed an improvement of 19.72%in microhardness and 77.5% of compressive strength in comparison with the base metal AZ 31 Magnesium alloy,with a tool rotational speed of 1400rpm.The values of tensile stress and percentage area reduction were recorded as less than that of the base metal matrix,but an increasing trend has been observed in the values of both with the improvement on rotational speeds of the tool.The effectual strengthening mechanisms are analyzed on the bases of SEM images and observed that discussed and found that grain refinement strengthening is the major contributor to the strength of the nanocomposite.展开更多
Cycloalkanes and cyclohexanols find diverse applications,including sustainable aviation fuel,fuel additives,and value-added chemicals.These compounds can be produced via complete or selective hydrodeoxygenation(HDO)of...Cycloalkanes and cyclohexanols find diverse applications,including sustainable aviation fuel,fuel additives,and value-added chemicals.These compounds can be produced via complete or selective hydrodeoxygenation(HDO)of lignin-derived phenolic monomers.In this study,a urea-assisted method was employed to control the size of Ru nanoparticles(NPs)and tune the surfaceactive sites on Ru metal supported on CN_(x).By adjusting the Ru-to-urea molar ratio,both the size of Ru NPs and the metallic-tooxide ratio of Ru were controlled,along with the incorporation of N atoms into the RuO_(2)surface coordination.In the absence of urea,the Ru/CN_(x)(1:0)catalyst,containing 4.8 nm Ru NPs,achieved complete HDO of 4-propyl guaiacol to n-propyl cyclohexane through ring saturation,followed by hydro-demethoxylation of the C–OCH_(3)group,and hydrogenolysis of the–OH group,with a 97.0%yield at an initial H_(2)pressure of 1.5 MPa,200℃,and 20 h in water.The final hydrogenolysis step was inhibited over the urea-assisted catalysts.The Ru/CN_(x)(1:8)catalyst,containing 3.1 nm Ru NPs,achieved a maximum selectivity of 67.6%for n-propyl cyclohexanol,along with complete conversion of 4-propyl guaiacol.Similar trends were observed in the product distribution when upgrading reductive catalytic fractionation bio-oil over Ru/CN_(x)(1:0)and Ru/CN_(x)(1:8).展开更多
文摘The ever-increasing demand for light weighted hard materials for transportation industries encouraged researchers to develop composites with excellent mechanical properties which can transform it into more economical and eco-friendly.Reinforcing the metals with carbonaceous nanomaterials are progressively in focus due to their excellent capability to inculcate and tailor the properties of MMCs.In the present research,a hybrid nanocomposite of MWCNT-Graphene-AZ31 Mg alloy has been developed by using variable tool rotation speeds with friction stir processing(FSP).Optimized reinforcement ratio of 1.6%vol.MWCNT and 0.3%vol.of graphene have been used with variable tool rotation speeds,whereas other processing parameters are kept constant.The developed specimens were investigated using standard testing equipment for evaluating and comparing the mechanical properties on the basis of the microstructure of the processing regions and their morphological analysis,according to the ASTM standards.The obtained results revealed an improvement of 19.72%in microhardness and 77.5% of compressive strength in comparison with the base metal AZ 31 Magnesium alloy,with a tool rotational speed of 1400rpm.The values of tensile stress and percentage area reduction were recorded as less than that of the base metal matrix,but an increasing trend has been observed in the values of both with the improvement on rotational speeds of the tool.The effectual strengthening mechanisms are analyzed on the bases of SEM images and observed that discussed and found that grain refinement strengthening is the major contributor to the strength of the nanocomposite.
基金supported by the Bio&Medical Technology Development Program of the National Research Foundation(NRF)funded by the Ministry of Science and ICT(MSIT),Republic of Korea(2022M3A9F3017700)Additional support from the the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Ministry of Trade,Industry&Energy,Republic of Korea is also acknowledged(RS-2024-00436868)the 10 C synchrotron beamline of the Pohang Acceleration Laboratory(PAL,Republic of Korea)under contact no.2024-3rd-10C-051。
文摘Cycloalkanes and cyclohexanols find diverse applications,including sustainable aviation fuel,fuel additives,and value-added chemicals.These compounds can be produced via complete or selective hydrodeoxygenation(HDO)of lignin-derived phenolic monomers.In this study,a urea-assisted method was employed to control the size of Ru nanoparticles(NPs)and tune the surfaceactive sites on Ru metal supported on CN_(x).By adjusting the Ru-to-urea molar ratio,both the size of Ru NPs and the metallic-tooxide ratio of Ru were controlled,along with the incorporation of N atoms into the RuO_(2)surface coordination.In the absence of urea,the Ru/CN_(x)(1:0)catalyst,containing 4.8 nm Ru NPs,achieved complete HDO of 4-propyl guaiacol to n-propyl cyclohexane through ring saturation,followed by hydro-demethoxylation of the C–OCH_(3)group,and hydrogenolysis of the–OH group,with a 97.0%yield at an initial H_(2)pressure of 1.5 MPa,200℃,and 20 h in water.The final hydrogenolysis step was inhibited over the urea-assisted catalysts.The Ru/CN_(x)(1:8)catalyst,containing 3.1 nm Ru NPs,achieved a maximum selectivity of 67.6%for n-propyl cyclohexanol,along with complete conversion of 4-propyl guaiacol.Similar trends were observed in the product distribution when upgrading reductive catalytic fractionation bio-oil over Ru/CN_(x)(1:0)and Ru/CN_(x)(1:8).
