Articles written in Sadhana
Volume 45 All articles Published: 27 March 2020 Article ID 0080
The virgin thermoplastics have numerous applications in fused deposition modelling (FDM) process. Commercially, different thermoplastics are recycled through extrusion (without any reinforcement as primary (1°) recycled materials) for enhancing their reusability and sustainability. However, hitherto very littlehas been reported on mechanical and thermal properties of cryogenic (cryo) milled 1° recycled ABS (to be used on FDM-based 3D printer). In the present research article the cryo ball milling of 1° recycled ABS thermoplastichas been reported to explore the influence of cryo environment (-196 °C) on mechanical, thermal and surface properties of the ABS-based feed stock filament (prepared through screw extrusion) for further use on commercial FDM set-up (without any hardware/software change). The process parameters of cryo-milling (like frequency of vibration, milling time and grinding media weight) have been selected for investigations using Taguchi-based design of experiment (DOE). The study results show significant improvement in peak strength (PS) of the cryo-milled ABS in comparison with non-cryo-milled ABS without any degradation of thermal properties (mainly heat capacity). As regards the process parameters of cryo-milling, 30-Hz frequency, 15-min milling time and 32-g media weight are the best settings for maximum PS. The maximum value of PS observed was 61.32 MPa. The optical photomicrographs supported with 3D rendered images were captured to support the surface characteristics and porosity level in the wires (to be used as feed stock filament for FDM) prepared with cryo-milled ABS (powder samples).
Volume 46 All articles Published: 18 August 2021 Article ID 0170
The present work proposes a cut-cell-based Direct Simulation Monte Carlo (DSMC) solver, for computing rarefied flows around complex geometries on Cartesian grids, wherein analytical expression for the surface of the immersed boundary (IB) is considered to evaluate cut-cell volume as well as to implement the particle–boundary interactions. Consequently the proposed DSMC solver models an accurate collision rate in the cut cells and ensures an analytically expressed IB-based implementation of the boundary conditions at thesurface of the immersed geometry, as in the IB methods for the continuum flows. Performance of the present Cartesian cut-cell-based DSMC solver is tested on a variety of rarefied gas flows around three complex geometries (cylinder, NACA 0012 airfoil and double-wedge airfoil) for various flow speeds (ranging from
Volume 47 All articles Published: 26 October 2022 Article ID 0212
In the past two decades’ significant studies have been reported on electrically conducting thermoplastic composites of acrylonitrile butadiene styrene (ABS), polyvinylidene fluoride (PVDF), etc. for the fabrication of novel energy storage devices (ESD) by 3D printing. But hitherto little has been reported on onlinecondition monitoring of ESD prepared by secondary (2°) recycling of ABS. This study reports the investigations on mechanical and electrical properties of NH4Cl–ZnCl2 (electrolyte) reinforced ABS composite (as 3D printed sensor) for online condition monitoring of ESD. In a typical dry cell, the electrolyte is one of the integral parts, and the change in its dielectric properties with the time/ applied electric load has been used to ascertain the health of ESD (online) as the internet of things (IoT) based solution (Bluetooth application) in industry sportsand medicine (ISM) band (2.4 GHz). Based on melt flow index (MFI), 10% NH4Cl and 10% ZnCl2 (by weight%) were reinforced in ABS for preparing 3D printed rectangular substrates as ring resonators for calculating dielectric constant (εr) and loss tangent/dissipation factor (tanδ) for the resonant frequency. Transmission line parameters (S21) were observed using a vector network analyzer (VNA), and a high-frequency structure simulation (HFSS) software package. The results are supported by morphological analysis of ABScomposite based on scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), 3D rendering, surface roughness (Ra), area mapping, current (I)–voltage (V), and Fourier transformed infrared (FTIR) characterization.
Volume 47 All articles Published: 30 November 2022 Article ID 0260
Polyethylene terephthalate (PET) thermoplastic polyester is durable, formable material that is widely used to manufacture consumer products like sailcloth, sailing spinnakers, food-grade containers, etc. for commercial and engineering applications. The recycling of PET is still a challenge because of its abundance,especially in low-income/developing countries. The present study reports the recycling of PET by utilizing the primary (1°) recycled PET (R-PET) for 3D printing-based sensor applications with the idea of converting waste to wealth. The investigations were performed on PET-based waste collected from institute campus canteens (in form of used food containers/soft drink bottles) after ascertaining their rheological, mechanical, morphological, bonding, and sensing capabilities. The sensing capabilities of R-PET were explored by performing a ring resonator test of a 3D-printed substrate using a vector network analyzer (VNA). The result of the study outlined that R-PET-based sensors may be used in sailcloth, and sailing spinnakers to monitor the location of boats in ashipyard/dock.