Other affiliations: National Institute of Technology, Warangal
Bio: T.C. Ramesh is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Finite element method & Vibration. The author has an hindex of 11, co-authored 27 publications receiving 396 citations. Previous affiliations of T.C. Ramesh include National Institute of Technology, Warangal.
TL;DR: In this paper, the effects of the shear parameter on the frequency and loss factors for various geometric properties and boundary conditions are also discussed for cylindrical shells with different core to facing thickness and length to radius ratios.
Abstract: The vibration and damping characteristics of three-layered cylindrical shells with a viscoelastic core constrained by isotropic facings are studied by using the finite element method. The finite element developed for the study has separate rotations in its displacement field for the core and facings. The element has three nodes and seven degrees of freedom per node. Results are presented for cylindrical shells with different core to facing thickness and length to radius ratios and three boundary conditions: clamped-clamped, simply supported and clamped-free. The effects of the shear parameter on the frequency and loss factors for various geometric properties and boundary conditions are also discussed.
TL;DR: In this paper, the authors investigated the hydrogen storage capacity of activated carbons derived from tamarind seeds by thermal, microwave and by chemical KOH activation treatment and found that the carbonization temperature and concentration of KOH play a major role in increasing the surface area, micropore volume and pore size.
Abstract: To make hydrogen economy a reality, the key technical challenges that need to be addressed are Hydrogen generation, transmission and storage for application in fuel cells. Among them, H 2 storage presents a major challenge to material scientists to meet the USDOE target of 5.5 wt%. The present paper investigates the hydrogen storage capacity of activated carbons derived from tamarind seeds by thermal, microwave and by chemical KOH activation treatment. The various parameters optimised to obtain high hydrogen storage capacity are KOH concentration, duty cycle of microwave pulsing, carbonization, hydrogen adsorption conditions etc., The surface area, micropore volume, pore size and nitrogen adsorption measurements were determined for all the samples and found that the carbonization temperature and concentration of KOH play a major role in increasing the surface area, micropore volume and pore size. We have obtained a high surface area activated carbon of 1785 m 2 g −1 , micropore volume of 0.94 cm 3 g −1 and pore size of around 0.8–1.1 nm. The maximum hydrogen storage capacity of these activated carbons from tamarind seeds at RT and 4.0 MPa was found to be 4.73 wt%, which is about 80% of the USDOE target. The samples also show good cyclic stability for hydrogen adsorption and desorption studies. These results suggest that activated carbons fabricated from tamarind seeds with high surface area and micropore volume will be an ideal candidate for hydrogen storage.
TL;DR: In this paper, the vibration and damping analysis of orthotropic cylindrical shells with a constrained viscoelastic core is carried out by using a finite element based on a discrete layer theory.
Abstract: The vibration and damping analysis of orthotropic cylindrical shells with a constrained viscoelastic core is carried out by using a finite element based on a discrete layer theory. The material damping of the facings is also included in the analysis. Results are represented for different geometric and material properties of the shell. The data and trends presented for various cases could be useful for designers in choosing damping treatments for composite shells.
TL;DR: In this article, the authors synthesized activated carbons from jute fibers, activated and treated using KOH to increase the porosity of samples, which helps in increasing the hydrogen storage capacity.
Abstract: Activated carbons (ACs) are being used as energy storage material especially for hydrogen storage application. In the present work, AC materials were synthesized from jute fibers, activated and treated using KOH to increase the porosity of samples. These AC samples retained the fibrous structure even after chemical activation at high temperature of 700 °C. Channel like structures were formed which helps to increase the hydrogen storage capacity. The surface area of these samples varied from 380 to 1220 m2 /g due to carbonization and activation treatment. The sample with high surface area of 1224 m2 /g showed a high hydrogen uptake capacity of 1.2 wt.% at 30 °C and 40 bar of H2 gas pressure. This sample also showed a high pore volume of 0.74 cm3 /g. These results indicate that the raw material jute fibers can be used as hydrogen storage medium after thermal and chemical treatment which increases the surface area and micropore volume.
08 Oct 2018
TL;DR: The tamarind seed coat-based hierarchical porous carbon possessed a unique configuration, making the material exhibit superior supercapacitor properties, and the synthesis process described is amenable for large-scale applications with less complexity.
Abstract: The overwhelming interest in supercapacitors has led to the search for various carbonaceous materials, leading to hierarchical porous carbons. Herein, we report a natural biomass (tamarind seed)-based hierarchical porous carbon without any template and activated by a facile scheme. The tamarind seed coat-based hierarchical porous carbon possessed a unique configuration, making the material exhibit superior supercapacitor properties. A single carbon fiber hosting a distinctive micro- and mesoporous structure formed a connecting thread between the pores. This unique structure enabled high surface area and high capacitance. The highest surface area obtained by this method was 1702 m2 g–1, whereas the capacitance was 157 F g–1 in 6 M KOH. Further, an ionic liquid-based electrolyte revealed 78 F g–1 at a current density of 0.5 A g–1. Outstanding capacity retentions of 96 and 93% were obtained over 1000 cycles at a current density of 2 A g–1 for aqueous (6 M KOH) and ionic liquid (1-butyl 3-methyl imidazoliumbi...
TL;DR: In this paper, researches on biochar are discussed in terms of production method and application, and different processes for biochar production, such as pyrolysis, gasification, hydrothermal carbonization, etc.
Abstract: Biochar produced during the thermochemical decomposition of biomass not only reduces the amount of carbon emitted into the atmosphere, but it is also an environment-friendly replacement for activated carbon and other carbon materials. In this review paper, researches on biochar are discussed in terms of production method and application. Different processes for biochar production, such as pyrolysis, gasification, hydrothermal carbonization, etc., are compared. Physical and chemical activation methods used to improve the physicochemical properties of biochar and their effects are also compared. Various environmental application fields of biochar including adsorption (for water pollutants and for air pollutants), catalysis (for syngas upgrading, for biodiesel production, and for air pollutant treatment), and soil conditioning are discussed. Recent research trend of biochar in other applications, such as fuel cell, supercapacitor, and hydrogen storage, is also reviewed.
TL;DR: In this paper, a summary of the use of lignocellulosic-based precursors to obtain activated carbon is provided, including physicochemical, micro/nanostructural, surface chemistry, textural and adsorption capacity features.
Abstract: Activated carbon is a porous material that has been in many important ages of the human history. Lignocellulosic precursors and biomass sources have become important materials to produce it because their use produces many benefits, mainly environmental. Nowadays, it is possible to find numerous research papers devoted to the synthesis characterization and applications of novel precursors to produce activated carbon. Hence, special attention must be given to the relationship among the selected precursor characteristics, the final microstructure and properties of carbon. The present work provides a summary of research works outlining the use of lignocellulosic–based precursors to obtain activated carbons. A brief description of the characterization techniques for both, the precursors and activated carbons, comprising: physicochemical, micro/nanostructural, surface chemistry, textural and adsorption capacity features is presented. Finally, the application of these materials in adsorption of heavy metals, dyes, volatile organic compounds, gas storage and electrochemical capacitors is also included.
TL;DR: This review summarizes the EM wave absorption application of biomass-derived PC materials from optimizing structure and designing composition and discusses corresponding synthetic mechanisms and development prospects.
Abstract: Currently, electromagnetic (EM) pollution poses severe complication toward the operation of electronic devices and biological systems. To this end, it is pertinent to develop novel microwave absorbers through compositional and structural design. Porous carbon (PC) materials demonstrate great potential in EM wave absorption due to their ultralow density, large surface area, and excellent dielectric loss ability. However, the large-scale production of PC materials through low-cost and simple synthetic route is a challenge. Deriving PC materials through biomass sources is a sustainable, ubiquitous, and low-cost method, which comes with many desired features, such as hierarchical texture, periodic pattern, and some unique nanoarchitecture. Using the bio-inspired microstructure to manufacture PC materials in mild condition is desirable. In this review, we summarize the EM wave absorption application of biomass-derived PC materials from optimizing structure and designing composition. The corresponding synthetic mechanisms and development prospects are discussed as well. The perspective in this field is given at the end of the article.
TL;DR: A comprehensive survey of the literature on curved shell finite elements can be found in this article, where the first two present authors and Liaw presented a survey of such literature in 1990 in this journal.
Abstract: Since the mid-1960s when the forms of curved shell finite elements were originated, including those pioneered by Professor Gallagher, the published literature on the subject has grown extensively. The first two present authors and Liaw presented a survey of such literature in 1990 in this journal. Professor Gallagher maintained an active interest in this subject during his entire academic career, publishing milestone research works and providing periodic reviews of the literature. In this paper, we endeavor to summarize the important literature on shell finite elements over the past 15 years. It is hoped that this will be a befitting tribute to the pioneering achievements and sustained legacy of our beloved Professor Gallagher in the area of shell finite elements. This survey includes: the degenerated shell approach; stress-resultant-based formulations and Cosserat surface approach; reduced integration with stabilization; incompatible modes approach; enhanced strain formulations; 3-D elasticity elements; drilling d.o.f. elements; co-rotational approach; and higher-order theories for composites. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this article, the relationship between the species of biomass-based electrode and properties of supercapacitors is systematically discussed, and the influence of specific morphologies, heteroatom-introducing and graphitization degree of active carbon on the electrochemical properties are analyzed in detail.
Abstract: The carbon material based biomass in energy storage has attracted much interest due to their environmental friendly, natural abundance and special porous structures. In this paper, the relationship between the species of biomass-based electrode and properties of supercapacitors are systematically discussed. On the one hand, the influence of the specific morphologies, heteroatom-introducing and graphitization degree of active carbon on the electrochemical properties are analyzed in detail, which give a promising direction for biomass-based carbon in clean energy field. On the other hand, machine learning, especially artificial neural network model, has been widely used as data mining technology to predict the electrochemical properties of electrode materials. It makes the structure-performance relationship for biomass-based supercapacitors more specifically. Current development in synthesis of active carbon from biomass combined with theoretical prediction is summarized, which provides a meaningful guidance into the application of energy storage supercapacitors. Current challenges and new trends on the biomass-based carbon materials in supercapacitors have also been proposed.