On the free vibration analysis of laminated composite and sandwich plates: A review of recent literature with some numerical results

Biocatalysts provide a major advantage to bio-based economy over chemical catalysts by catalyzing various useful transformations in an environment friendly manner along with other major benefits of selectivity, specificity, and low energy consumption. Since last decade, cellulase is the 3rd highest used enzyme in industry in various processes. Xylanase is also one amongst the widely used enzymes, and many industrial applications require synergistic action of both of these enzymes. These applications predominantly include bioethanol production, deinking of waste paper, animal feed processing, food processing, paper and pulp production, removal of fine fibers from textile material (biostoning), and pharmaceuticals. These enzymes are produced by microorganisms (fungi and bacteria), and hence, the microorganisms producing both cellulases and xylanases are in high demand by these industries. This review focuses on the synergistic applications of cellulase and xylanase enzymes across various industrial sectors. It also discusses the potential applications and the need of the microbial systems (fungi and bacteria) secreting both of these enzymes and the future prospects of their development into an integral part of various industrial processes.

Cellulase and xylanase synergism in industrial biotechnology

This study illustrated the pyrolysis of banana peel (BP) as a potential waste management solution. Samples were characterized through Fourier transform infrared spectrometry (FTIR), elemental analysis, and high heating value (HHV) calculation. After pyrolysis experiments were performed at different heating rates (10, 20, 30, and 40 °C min−1) by using a thermogravimetric analyzer coupled with FTIR (TG-FTIR), the apparent activation energies were computed with Friedman, Kissinger–Akahira–Sunose (KAS), and Flynn–Wall–Ozawa (FWO) methods, and the evolved gaseous products were analyzed simultaneously. During pyrolysis, BP underwent three devolatilization steps accompanied by the evolution of some major gaseous products, including CO2, CH4, H2O, CH3COOH, C C, C6H5OH, HCOOH, and CH3CH2OH. Among them, C C, CH3COOH, and CO2 accounted for approximately 71.56% of the total gaseous products. Gas evolution was more significantly influenced by the pyrolysis temperature than by the heating rate. Pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analysis confirmed the presence of some high-energy compounds and valuable chemicals containing aromatic, aldehyde, ketone, and other functional groups. In terms of preliminary energy balance, more than 70% of the total energy output was attributed to the liquid pyrolytic products followed by the solid and gaseous products. The energy recovery ratio of BP pyrolysis was superior to that of other fuel feedstocks. This work provided insights into resolving environmental problems associated with BP management by pyrolyzing BP as a potential source of renewable bioenergy.

Thermo-kinetics and gaseous product analysis of banana peel pyrolysis for its bioenergy potential

The past 20 years has seen rapid development of value-added food products. Using largely wasted fruit by-products has created a potential for sustainable use of these edible materials. The high levels of antioxidant activity, phenolic compounds, dietary fibres and resistant starch in banana pulp and peel have made this tropical fruit an outstanding source of nutritive ingredient for enrichment of foodstuffs. Accordingly, processing of separate banana parts into flour has been of interest by many researchers using different methods (oven drying, spouted bed drier, ultrasound, pulsed vacuum oven, microwave, spray drying and lyophilization). Regarding the high level of bioactive compounds, especially resistant starch in banana flour, the application of its flour in starchy foods provides a great opportunity for product development, even in gluten free foods. This review aims to provide concise evaluation of the health benefits of banana bioactive components and covers a wide range of literature conducted on the application of different parts of banana and the flour produced at various ripeness stages in the food industry. Of particular interest, the impact of drying methods on banana flour properties are discussed.

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Production, application and health effects of banana pulp and peel flour in the food industry.

This paper presents a stochastic dynamic analysis of functionally graded plates by following an efficient neural network based approach coupled with the finite element method. An isoparametric quadratic element having eight nodes is considered for the finite element analysis of pre-twisted functionally graded cantilever plates subjected to variation in geometric parameters, material properties and temperature. Both individual and compound effects of stochasticity in the uncertain input parameters are accounted to quantify their influence on the first three natural frequencies, mode shapes, and frequency response functions of functionally graded plates. A sensitivity analysis is conducted to ascertain the relative effects of various prospective sources of uncertainty. Latin hypercube sampling is utilised to train the efficient surrogate models, which are employed as a medium of uncertainty propagation. The comparative performance of artificial neural network and polynomial neural network is assessed in the stochastic dynamic analysis of the pre-twisted functionally graded plates from the viewpoint of accuracy and computational efficiency. The results are validated with respect to direct Monte Carlo simulation based on the finite element model of the functionally graded plates. It is observed that the artificial neural network based algorithm can achieve a significant level of computational efficiency without compromising the accuracy of results. The results presented in this article reveal that the source uncertainties of functionally graded plates have a significant effect on the dynamic responses of the structure.

Stochastic dynamic analysis of twisted functionally graded plates

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Review on Stress and Vibration Analysis of Composite Plates

Conversion of agro-industrial wastes to energy is an innovative approach for waste valorization and management which also mitigates environmental pollution. In this view, present study investigated the feasibility of producing bioethanol from banana peels using cocktail of depolymerizing enzyme/s. We isolated Geobacillus stearothermophilus HPA19 from natural resource which produces cocktail of thermo-alkali-stable xylano-pectino-cellulolytic enzyme/s using wheat bran within 24 h. The optimal temperature and pH for xylanase, filter paper cellulase and pectinase were 80, 70 and 80 °C, and 9.0, 8.0 and 9.0, respectively. Cocktail enzymes showed stability at high temperature (80 °C) and pH (10.0). Ni2+ and Zn2+ promoted the relative activity of xylanase and FPase, whereas Na+, Ca2+ and K+ promoted pectinase activity. Cocktail was assessed in saccharification of banana peel. Reducing sugar obtained (37.06 mg ml−1) after one variable at a time (OVAT) method is greatly influenced by enzyme dose. Further, response surface methodology was used to optimize saccharification leading to twofold increase in reducing sugar. Maximum ethanol production (21.1 gl−1) was achieved through fermentation giving the efficiency of 76.5% within 30 h. Hence utilization of waste biomass for production of value-added products through biotechnological intervention not only helps to combat environmental pollution but also contributes significantly to the economy.

Development of eco-friendly process for the production of bioethanol from banana peel using inhouse developed cocktail of thermo-alkali-stable depolymerizing enzymes

The application of FEM is shown for free vibration analysis of moderately thick laminated composite plates with edges elastically restrained against translation and rotation. The governing equations employed are based on the first order shear deformation theory including the effects of rotary inertia. Several combinations of translational and rotational elastic edge constraints are considered. Convergence study with respect to the number of nodes has been carried out and the results are compared with those from past investigations available only for simpler problems. Angle-ply and cross-ply laminates with different thickness-to-length ratios are examined. Comparisons are made with results for thin as well as moderately thick laminated plates.

Free vibration analysis of laminated composite plates with elastically restrained edges using FEM

Cutouts are commonly used as access port for mechanical and electrical structures. Most of the structures generally work under severe dynamic loading and different constrained conditions during their service life. This may lead to vibration of the structure. Therefore, it is necessary to predict the vibration responses of laminated composite plates with cutouts precisely with less computational cost and good accuracy of these complex structures. A suitable finite element model is proposed and developed based on first order shear deformation theory using ANSYS parametric design language (APDL) code. The model has been discretized using an appropriate eight nodded element (SHELL 281) from the ANSYS element library. The free vibrations are computed using Block-Lanczos algorithm. The convergence study has been done of the developed model and compared with those available published literature. Effects of different geometric parameters (aspect ratio, thickness ratio, boundary conditions, number of layers, angle of lamina geometry of cutout, cutout side to plate side ratio and distance between cutouts) and material properties on the free vibration responses are discussed in detail. The frequency increases with increase in the number of layers, modulus ratio of plate and angle of lamina. The frequency decreases with increase in aspect ratio, thickness ratio, size of cutout and distance between cutouts. The boundary conditions of the plate play an important role in the free vibrations of the plate with cutouts. The Non-dimensional frequencies are higher for fully clamped boundary condition in comparison to other boundary conditions.

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Avadesh K. Sharma

Papers

Review on Stress and Vibration Analysis of Composite Plates

Development of eco-friendly process for the production of bioethanol from banana peel using inhouse developed cocktail of thermo-alkali-stable depolymerizing enzymes

Free vibration analysis of laminated composite plates with elastically restrained edges using FEM

Study of free vibration analysis of laminated composite plates with triangular cutouts

Free vibration analysis of moderately thick antisymmetric cross-ply laminated rectangular plates with elastic edge constraints