Diabetic autonomic neuropathy

The low or lack of solubility of fullerenes, carbon nanotubes and graphene/graphite in organic solvents and water severely hampers the study of their chemical functionalizations and practical applications. Covalent and noncovalent functionalizations of fullerenes and related materials via mechanochemistry seem appealing to tackle these problems. In this review article, we provide a comprehensive coverage on the mechanochemical reactions of fullerenes, carbon nanotubes and graphite, including dimerizations and trimerizations, nucleophilic additions, 1,3-dipolar cycloadditions, Diels–Alder reactions, [2 + 1] cycloadditions of carbenes and nitrenes, radical additions, oxidations, etc. It is intriguing to find that some reactions of fullerenes can only proceed under solvent-free conditions or undergo different reaction pathways from those of the liquid-phase counterparts to generate completely different products. We also present the application of the mechanical milling technique to complex formation, nanocomposite formation and enhanced hydrogen storage of carbon-related materials.

Mechanochemistry of fullerenes and related materials

Self-propagating high-temperature synthesis (SHS) or combustion synthesis (CS) is a rapidly developing research area. SHS materials are being used in various fields, including mechanical and chemical engineering, medical and bioscience, aerospace and nuclear industries. The goal of the present paper is to provide a comprehensive state-of-the-art review and to analyse a critical mass of knowledge in the field of SHS materials and coatings. We also briefly discuss the history and scientific foundations of SHS along with an overview of the technological aspects for synthesis of different materials, including powders, ceramics, metal-ceramics, intermetallides, and composite materials. Application of CS in the field of surface engineering is also discussed focusing on two main routes for applying SHS to coating deposition: (i) single-step formation of the desired coatings and (ii) use of SHS-derived powders, targets or electrodes in the coating deposition processes.

Self-propagating high-temperature synthesis of advanced materials and coatings

Tensile properties of carbon nanotubes reinforced aluminum matrix composites: A review

In electrical or thermal appliances, heat (thermal energy) must either be added into or removed from a system to maintain operational stability. Heat pipes can enhance the heat transfer capabilities without needing a significant temperature gradient between heat sources and heat sinks. The effectiveness of heat pipes is due to the latent heat of phase change of the working fluid within (i) condensation and (ii) evaporation stages. The latent heat of phase change greatly exceeds the sensible heat capacity. Heat pipes may rely on gravity, wicks, centrifugal force or in some cases even a magnetic field to help return condensate flow from the condenser to the evaporator. Wicks in heat pipes are classified into three groups: sintered, groove and mesh types. This review attempts to cover various types of heat pipes such as thermal diodes, variable conductance, pulsating, etc. The application of nanotechnology in heat pipes can be separated into two groups: nanoparticles and nanobubbles, with the latter receiving considerably less attention than the former. The hybridisation of heat pipe technology is also possible and has been discussed along with its future research potential.

Heat utilisation technologies: A critical review of heat pipes

Gamma titanium alumindes are intermetallics, which have very narrow working range. Hot isothermal working is the most suitable process for hot working of alloy. Accordingly, hot isothermal compression test is carried out on reaction synthesized and homogenized titanium aluminide alloys at different temperatures and strain rates using Gleeble thermomechanical simulator. Three alloys of Ti48Al2Cr2Nb0.1B (atom%) have been used in the study. Stress–strain data obtained from the test has been used to construct processing map, which indicates the safe and unsafe working zone. Strain rate sensitivity and Zener–Hollomon parameter has been calculated. Further, constitutive equations have been generated and verified. It is found that alloy has good workability in the temperature range of 1223–1423 K at strain rates of 0.01–0.001 s −1 . In this range of parameters, the alloys nearly follow the constitutive equations.

Hot workability of γ + α2 titanium aluminide: Development of processing map and constitutive equations

Calorimetric study on mechanically milled aluminum and multiwall carbon nanotube composites

Studies on the processing of nickel base porous wicks for capillary pumped loop for thermal management of spacecrafts

γ+α 2 titanium aluminide alloys made through reaction synthesis have been used for deformation study. Hot isothermal compression test is carried out to study the deformation characteristics of the alloys using Gleeble thermomechanical simulator. Three alloys based on Ti48Al2Cr2Nb0.1B (at%) are tested at different temperatures and at different strain rates. True stress-true strain plots are analyzed along with analysis of tested specimens. Tested specimens are observed under optical and electron microscopes. Presence of various deformation morphologies and phases were confirmed. Microhardness evaluation and transmission electron microscopic examination are used to confirm the presence of different phases. It is found that dynamic recrystallization is mainly playing role in deformation of these alloys. Presence of dynamically recrystallized (DRX) grains and lamellar microstructures is confirmed at the intergranular area and inside the grains, respectively. A nucleation model is suggested for DRX and lamellar grain nucleation during deformation. Attempt has been made to quantify the presence of various phases through optical microscopy. Hot workability map is also suggested on the basis of microstructural and visual observation of compression tested specimens.

P. P. Sinha

Papers

Hot workability of γ + α2 titanium aluminide: Development of processing map and constitutive equations

Calorimetric study on mechanically milled aluminum and multiwall carbon nanotube composites

Studies on the processing of nickel base porous wicks for capillary pumped loop for thermal management of spacecrafts

Deformation behaviour of γ+α2 Ti aluminide processed through reaction synthesis

Differential scanning calorimetry and reaction kinetics studies of γ + α2 Ti aluminide