It is shown by informatics that the high frequency short ranged modes exert a significant influen... more It is shown by informatics that the high frequency short ranged modes exert a significant influence in impeding thermal transport through isotope substituted graphene nanoribbons. Using eigenvalue decomposition methods, we have extracted features in the phonon density of states spectra that reveal correlations between isotope substitution and phonon modes. This study also provides a data driven computational framework for the linking of materials chemistry and transport properties in 2D systems.
In the present work, the heat transfer behavior during induction heating of a cylindrical aluminu... more In the present work, the heat transfer behavior during induction heating of a cylindrical aluminum billet is performed numerically. The heating process is represented by the energy conservation equation where the heat generation during heating is added as a volumetric source term. The evolution of latent heat during melting is also added as a volumetric source term. The continuity and the momentum conservation equations are considered to represent the flow field after melting starts. These governing equations are solved based on the control volume method. The enthalpy update scheme is used for evolution of melt-fraction during heating. The work predicts the evolution of temperature during heating, the distributions of temperature and melt-fraction in the domain. Subsequently, a parametric study is also performed.
The intrinsic mechanical properties of nanocellulose, with a specific stiff-ness and specific str... more The intrinsic mechanical properties of nanocellulose, with a specific stiff-ness and specific strength higher than most metals and alloys, are superior engi-neering materials. This makes the renewable yet abundantly available nanocel-lulose a promising material in multi-fold stimulating applications involving high strength and toughness. This chapter sheds light on the principle mechanistic design features leading to the superb mechanical properties in nanocellulose-based mate-rials. Some of them, such as nanocellulose-based films, macrofibers, bulk wood and lightweight nanocomposites, are discussed. Different modeling approaches focusing on the underlying mechanism behind these fascinating mechanical properties are also reviewed. Finally, some broader future perspectives that can enrich this discipline are analyzed, which hopefully will stimulate the readers to explore the fertile oppor-tunities of nanocellulose-based sustainable materials engineering in the foreseeable future.
Conventional strategies for materials design have long been used by leveraging primary bonding, s... more Conventional strategies for materials design have long been used by leveraging primary bonding, such as covalent, ionic, and metallic bonds, between constituent atoms. However, bond energy required to break primary bonds is high. Therefore, high temperatures and enormous energy consumption are often required in processing and manufacturing such materials. On the contrary, intermolecular bonds (hydrogen bonds, van der Waals forces, electrostatic interactions, imine bonds, etc.) formed between different molecules and functional groups are relatively weaker than primary bonds. They, thus, require less energy to break and reform. Moreover, intermolecular bonds can form at considerably longer bond lengths between two groups with no constraint on a specific bond angle between them, a feature that primary bonds lack. These features motivate unconventional strategies for the material design by tuning the intermolecular bonding between constituent atoms or groups to achieve superior physical...
Synthetic structural materials with exceptional mechanical performance suffer from either large w... more Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk nat...
Synthetic structural materials with exceptional mechanical performance suffer from either large w... more Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk nat...
It is shown by informatics that the high frequency short ranged modes exert a significant influen... more It is shown by informatics that the high frequency short ranged modes exert a significant influence in impeding thermal transport through isotope substituted graphene nanoribbons. Using eigenvalue decomposition methods, we have extracted features in the phonon density of states spectra that reveal correlations between isotope substitution and phonon modes. This study also provides a data driven computational framework for the linking of materials chemistry and transport properties in 2D systems.
In the present work, the heat transfer behavior during induction heating of a cylindrical aluminu... more In the present work, the heat transfer behavior during induction heating of a cylindrical aluminum billet is performed numerically. The heating process is represented by the energy conservation equation where the heat generation during heating is added as a volumetric source term. The evolution of latent heat during melting is also added as a volumetric source term. The continuity and the momentum conservation equations are considered to represent the flow field after melting starts. These governing equations are solved based on the control volume method. The enthalpy update scheme is used for evolution of melt-fraction during heating. The work predicts the evolution of temperature during heating, the distributions of temperature and melt-fraction in the domain. Subsequently, a parametric study is also performed.
The intrinsic mechanical properties of nanocellulose, with a specific stiff-ness and specific str... more The intrinsic mechanical properties of nanocellulose, with a specific stiff-ness and specific strength higher than most metals and alloys, are superior engi-neering materials. This makes the renewable yet abundantly available nanocel-lulose a promising material in multi-fold stimulating applications involving high strength and toughness. This chapter sheds light on the principle mechanistic design features leading to the superb mechanical properties in nanocellulose-based mate-rials. Some of them, such as nanocellulose-based films, macrofibers, bulk wood and lightweight nanocomposites, are discussed. Different modeling approaches focusing on the underlying mechanism behind these fascinating mechanical properties are also reviewed. Finally, some broader future perspectives that can enrich this discipline are analyzed, which hopefully will stimulate the readers to explore the fertile oppor-tunities of nanocellulose-based sustainable materials engineering in the foreseeable future.
Conventional strategies for materials design have long been used by leveraging primary bonding, s... more Conventional strategies for materials design have long been used by leveraging primary bonding, such as covalent, ionic, and metallic bonds, between constituent atoms. However, bond energy required to break primary bonds is high. Therefore, high temperatures and enormous energy consumption are often required in processing and manufacturing such materials. On the contrary, intermolecular bonds (hydrogen bonds, van der Waals forces, electrostatic interactions, imine bonds, etc.) formed between different molecules and functional groups are relatively weaker than primary bonds. They, thus, require less energy to break and reform. Moreover, intermolecular bonds can form at considerably longer bond lengths between two groups with no constraint on a specific bond angle between them, a feature that primary bonds lack. These features motivate unconventional strategies for the material design by tuning the intermolecular bonding between constituent atoms or groups to achieve superior physical...
Synthetic structural materials with exceptional mechanical performance suffer from either large w... more Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk nat...
Synthetic structural materials with exceptional mechanical performance suffer from either large w... more Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk nat...
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Papers by Upamanyu Ray