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result(s) for
"Tiwary, Chandra S"
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Bacteria as Bio-Template for 3D Carbon Nanotube Architectures
by
Kosolwattana, Suppanat
,
Mohite, Aditya D.
,
Silwal, Sushila
in
140/133
,
140/146
,
60 APPLIED LIFE SCIENCES
2017
It is one of the most important needs to develop renewable, scalable and multifunctional methods for the fabrication of 3D carbon architectures. Even though a lot of methods have been developed to create porous and mechanically stable 3D scaffolds, the fabrication and control over the synthesis of such architectures still remain a challenge. Here, we used Magnetospirillum magneticum (AMB-1) bacteria as a bio-template to fabricate light-weight 3D solid structure of carbon nanotubes (CNTs) with interconnected porosity. The resulting porous scaffold showed good mechanical stability and large surface area because of the excellent pore interconnection and high porosity. Steered molecular dynamics simulations were used to quantify the interactions between nanotubes and AMB-1 via the cell surface protein MSP-1 and flagellin. The 3D CNTs-AMB1 nanocomposite scaffold is further demonstrated as a potential substrate for electrodes in supercapacitor applications.
Journal Article
Development of a self-consistent thermodynamic database for Ga-In-Te system and experimental validation: a potential system for thermoelectric application
by
Paek, Min-Kyu
,
Kumar, Bhupendra
,
Paliwal, Manas
in
Binary systems
,
Eutectic composition
,
Evaluation
2022
The Ga-In-Te alloy is one of the promising thermoelectric materials and its eutectic compositions can be expected to show improved thermoelectric behavior. In order to find the possible eutectic compositions in the ternary system, the thermodynamic modeling approach was considered based on the Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD) technique. Thermodynamic optimization and critical evaluation of the ternary Ga-In-Te system with the sub-binaries were performed using modified quasichemical model (MQM) for the liquid solution and compound energy formalism (CEF) for the solid solutions, respectively. By integrating the optimized sub-binaries, thermodynamic properties and phase diagram information in the ternary Ga-In-Te system were successfully reproduced. The asymmetric ternary interpolation method was applied to evaluate the Gibbs free energy of the ternary liquid solution. There were two line compounds of Ga2Te3-In2Te3 as a complete mutual solubility and InTe with limited solubility of Ga in the ternary system. The accuracy of the developed database was verified by comparing the measured phase transition temperatures with predicted phase diagrams and the microstructural analysis data with equilibrium cooling calculations.
Journal Article
Understanding the mechanics of complex topology of the 3D printed Anthill architecture
by
Kushwaha, Brijesh
,
Kumar, Avinash
,
Sadasivuni, Kishor Kumar
in
3-D printers
,
Cement
,
Computed tomography
2022
The present work aimed to investigate the deformation behavior of complex ant mound architectures under compression. We have used the cement casting method to extract four different ant nest morphologies. These casted cement structures were digitalized using a 3D micro-computer tomography scan. The digitized structures were simulated under different loading conditions using finite-element methods (FEMs). In order to supplement the numerical understanding, the digital architectures were 3D printed and experimentally tested under uniaxial loading conditions. Ants produce a variety of complex architectures for adapting to the surrounding environment and ants’ needs. Ant mound consists of at least one pillar with a broad base tapered toward its tip. Anthill architectures have unique topological features. Mechanical strength of ant mould can be 600 times enhanced by tuning topology. Thickness and angle of pillars have huge effect on load-bearing property. The branched structures can endure larger stress and deform in the process under a volumetric pressure application, making them sacrificial units for extreme disasters like floods and earthquakes. The 3D printing experiments and FEMs simulations are needed to tackle the complex ant mound architectures and appear in good agreement, suggesting a robust design and thus the possibility of constructing anthill-inspired civil buildings with a tree-trunk-like geometry.
Journal Article
Mechanical Response of Pentadiamond: A DFT and Molecular Dynamics Study
by
Tromer, Raphael M
,
Woellner, Cristiano F
,
Tiwary, Chandra S
in
Allotropy
,
Dynamic stability
,
Elastic deformation
2021
Pentadiamond is a recently proposed new carbon allotrope consisting of a network of pentagonal rings where both sp\\(^2\\) and sp\\(^3\\) hybridization are present. In this work we investigated the mechanical and electronic properties, as well as, the thermal stability of pentadiamond using DFT and fully atomistic reactive molecular dynamics (MD) simulations. We also investigated its properties beyond the elastic regime for three different deformation modes: compression, tensile and shear. The behavior of pentadiamond under compressive deformation showed strong fluctuations in the atomic positions which are responsible for the strain softening at strains beyond the linear regime, which characterizes the plastic flow. As we increase temperature, as expected, Young's modulus values decrease, but this variation (up to 300 K) is smaller than 10\\% (from 347.5 to 313.6 GPa), but the fracture strain is very sensitive, varying from \\(\\)44\\% at 1K to \\(\\)5\\% at 300K.
Mechanical Properties of 3D-Printed Pentadiamond
2021
In this work, We combined fully atomistic molecular dynamics and finite elements simulations with mechanical testings to investigate the mechanical behavior of atomic and 3D-printed models of pentadiamond. Pentadiamond is a recently proposed new carbon allotrope, which is composed of a covalent network of pentagonal rings. Our results showed that the stress-strain behavior is almost scale-independent. The stress-strain curves of the 3D-printed structures exhibit three characteristic regions. For low-strain values, this first region presents a non-linear behavior close to zero, followed by a well-defined linear behavior. The second regime is a quasi-plastic one and the third one is densification followed by structural failures (fracture). The Young's modulus values decrease with the number of pores. The deformation mechanism is bending-dominated and different from the layer-by-layer deformation mechanism observed for other 3D-printed structures. They exhibit good energy absorption capabilities, with some structures even outperforming kevlar. Interestingly, considering the Ashby chart, 3D-printed pentadiamond lies almost on the ideal stretch and bending-dominated lines, making them promising materials for energy absorption applications.
Topological engineered 3D printing of Architecturally Interlocked Petal-Schwarzites
by
Bastos, Leonardo V
,
Tiwary, Chandra S
,
Woellner, Cristiano F
in
Compressive strength
,
Energy absorption
,
Mechanical analysis
2023
The topologically engineered complex Schwarzites architecture has been used to build novel and unique structural components with a high specific strength. The mechanical properties of these building blocks can be further tuned, reinforcing with stronger and high surface area architecture. In the current work, we have built six different Schwarzites structures with multiple interlocked layers, which we named architecturally interlocked petal-schwarzites (AIPS). These complex structures are 3D printed into macroscopic dimensions and compressed using uniaxial compression. The experimental results show a strong dependency of mechanical response on the number of layers and topology of the layers. Fully atomistic molecular dynamics compressive simulations were also carried out, and the results are in good agreement with experimental observations. They can explain the underlying AIPS mechanism of high specific strength and energy absorption. The proposed approach opens a new perspective on developing new 3D-printed materials with tunable and enhanced mechanical properties.
Mechanical Energy Absorption of Architecturally Interlocked Petal-Schwarzites
by
Bastos, Leonardo V
,
Tiwary, Chandra S
,
Woellner, Cristiano F
in
Axial stress
,
Carbon
,
Compressive properties
2023
We carried out fully atomistic reactive molecular dynamics simulations to study the mechanical behavior of six newly proposed hybrid schwarzite-based structures (interlocked petal-schwarzites). Schwarzites are carbon crystalline nanostructures with negative Gaussian curvature created by mapping a TPMS (Triply Periodic Minimal Surface) with carbon rings containing six to eight atoms. Our simulations have shown that petal-schwarzite structures can withstand uni-axial compressive stress up to the order of GPa and can be compressed past 50 percent strain without structural collapse. Our most resistant hierarchical structure has a calculated compressive strength of 260~GPa and specific energy absorption (SEA) of 45.95 MJ/kg, while possessing a mass density of only 685 kg/m\\(^3\\). These results show that these structures could be excellent lightweight materials for applications that require mechanical energy absorption.
Zeolite-inspired 3d printed structures with enhanced mechanical properties
by
Kushwaha, Brijesh
,
Roy, Ajit K
,
Sajadi, Mohammad
in
Architecture
,
Automotive parts
,
Bearing capacity
2020
Specific strength (strength/density) is a crucial factor while designing high load bearing architecture in areas of aerospace and defence. Strength of the material can be enhanced by blending with high strength component or, by compositing with high strength fillers but both the options has limitations such as at certain load, materials fail due to poor filler and matrix interactions. Therefore, researchers are interested in enhancing strength of materials by playing with topology/geometry and therefore nature is best option to mimic for structures whereas, complexity limits nature mimicked structures. In this paper, we have explored Zeolite-inspired structures for load bearing capacity. Zeolite-inspired structure were obtained from molecular dynamics simulation and then fabricated via Fused deposition Modeling. The atomic scale complex topology from simulation is experimentally synthesized using 3D printing. Compressibility of as-fabricated structures was tested in different direction and compared with simulation results. Such complex architecture can be used for ultralight aerospace and automotive parts.
Schwarzite and schwarzynes based load-bear resistant radial cellular griding-based 3D printed structures
by
Tiwary, Chandra S
,
Oliveira, Eliezer F
,
Galvao, Douglas S
in
Antiballistic materials
,
Cellular structure
,
Compression tests
2021
Nature-occurring structures exhibiting unique topological features such as complex and gradient porosity has been the basis to create new materials and/or structures. Most studies have been focused on complex periodic porous structures but gradient porous ones have not been yet fully investigated for stable structural designs. In this work, we have proposed and tested a new approach to create cellular griding structures, in which the mass density varies from the center to the borders, i.e, a radial gradient. To create these new structures we exploited the topology of two carbon-based families with different pore sizes, the schwarzites, and schwarzynes. We created fully atomistic models that were translated into macroscale ones that were then 3D printed. The mechanical behavior of the gradient structures was investigated by molecular dynamics simulations and mechanical compression tests of the printed models. Our results show that their mechanical response can be engineered (for instance, in terms of energy absorption, ballistic performance, etc.) and can outperform their corresponding density uniform structures.
Rain energy harvesting using atomically thin Gadolinium Telluride decorated 3D Printed nanogenerator
by
Mukherjee, Madhubanti
,
Singh, Abhisek K
,
Parui, Arko
in
Current carriers
,
Density functional theory
,
Droplets
2022
The 3D printing technology offers an innovative approach for developing energy storage devices to create facile and low-cost customized electrodes for modern electronics. Generating electric potential by moving a droplet of ionic solution over two-dimensional (2D) materials is a novel method for rain energy harvesting. This work demonstrated a liquid-solid contact electrification-based 3D printed nanogenerator where raindrop passes through the positively charged ultrathin Gadolinium Telluride (Gd2Te3) sheets. Experimental results showed that voltage as high as ~0.6 V could be generated by moving a droplet of ionic solution on the decorated 3D printed nanogenerator. The output efficiency of the nanogenerator is increased ~400% by enhancing the surface area of copious 3D printed porous structures. Density Functional Theory (DFT) calculations are done, revealing that the high electrical conductivity of (112) surface of Gd2Te3 is due to the p-type charge carriers. Additionally, we illustrate the enhancement of the output performance (~0.8V) by using a graphite rod and arbitrarily manipulating the surface charge. Therefore, this work can open up a new avenue to advance scientific research of Blue energy harvesting and tackle the energy crisis.