Investigation of Stretch and Recovery Property of Weft Knitted Regular Rib Fabric

Weft knitted regular rib (1×1) fabric stretch and recovery property are very tough to control. This project and thesis work have been devoted to studying the effect of variation of stitch length, yarn count, and GSM on the stretch and recovery properties of weft knit regular rib fabric. Three yarn counts, each with 4 level of stitch length, was manufactured for the purpose of this experiment, remaining the machine set up, dyeing and finishing process constant. In this research, it was found that the better stretch and recovery property of regular rib fabric can be produced by using 2.6 mm to 2.65 mm stitch length for yarn count of Ne 28/1 KH and GSM of 195 to 205

Combining COMSOL modeling with different piezoelectric materials to design MEMS cantilevers for marine sensing robotics

This work presents a novel, highly sensitive, and directional piezoelectric cantilever-based micro-electro-mechanical system (MEMS) device conceived using a biomimetic approach of a fish’s lateral line system for marine sensing robotics. The device will consist of twelve cantilevers with different lengths in a cross-shaped configuration made with a piezoelectric thin film (PZT, ZnO, BaTiO3) embedded between the top and bottom metals, Platinum (Pt) and Aluminum (Al), used as electrodes. This unique design of cantilevers in circular shapes has the advantage of directional response. A comparative study of these piezoelectric materials was performed analytically through the finite element method to design, model, and simulate our device in COMSOL software. Cantilever microstructures were simulated with lengths ranging from 100 to 1000 mm. The results show that PZT has the best performance with these materials. The maximum potential voltage was shown as 1.9 mV using the PZT material cantilever with 29 µm displacement

Development of a novel design and modeling of MEMS piezoelectric cantilever-based chemical sensors

The analytical modeling of thin-film, multilayered piezoelectric microcantilevers is presented in this work. Piezoelectric microcantilevers were used in chemical sensors. Different types of probe coatings were applied to these types of microcantilevers. A position-sensitive sensor (PSS) system was used to identify chemical ingredients in materials with high sensitivity, and external voltage was measured in mV. The maximum voltage generated for the sensor was 39 mV. This range of voltage is suitable for sensing electronic systems. The angle change in a microcantilever in a liquid or gas environment identifies a material’s chemical ingredients. A microcantilever deflects, resulting in varying voltages in the analysis of materials. COMSOL software and equations were used for analytical simulations to determine the optimal design parameters. COMSOL software model development and MEMS design were involved in the analytical simulations. This paper examines an analytical model of the cantilever and discusses the fabrication process

A comprehensive comparison of the hargreaves isothermal model with the Schmidt model for the gamma stirling engine

The Stirling engine, a type of external combustion engine utilizing a compressible fluid as its working medium, holds promise as a highly efficient device for converting heat into mechanical work at Carnot efficiency. This research conducts a detailed analysis, comparing the Hargreaves isothermal model and the Schmidt model specifically for the gamma-type Stirling engine. The study examines the impact of dead volume on the engine’s performance, revealing that the engine network is solely influenced by these volumes. Furthermore, it highlights the effectiveness of the Hargreaves model for the performance analysis of gamma-type Stirling engines

Enhancing gamma stirling engine performance through genetic algorithm technique

The Stirling engine, invented in 1816, was initially lacking comprehensive scientific under-standing, which only surfaced after a considerable 50-year period. In the present era, impressive strides have been made in enhancing the performance of Stirling engines by implementing thermodynamic cycles. Despite these advancements, there remains untapped potential for further improvements by applying soft computing methods. To address this, the focal point of this research paper centres around optimizing the Stirling engine, specifically focusing on a gamma-type double-piston Stirling engine and leveraging genetic algorithms to achieve the desired enhancements. The results from this analysis are meticulously compared with experimental data, validating the approach’s efficacy. Additionally, this paper explores the potential impact of utilizing cryogenic fluids as coolants on the Stirling engine’s performance

Finite physical dimensions thermodynamic analysis for gamma stirling engine

In the foreseeable future, the depletion of finite fossil fuel reserves is a growing concern due to the increasing consumption of these resources by humans. Moreover, the emission of greenhouse gases from fossil fuel consumption contributes to global warming, resulting in significant harm to the Earth’s ecosystem. The Stirling engine (SE) offers an outstanding solution for harnessing various heat sources, including solar, nuclear, and fossil fuels, among others. It provides numerous advantages, such as high efficiency, a long lifespan, low noise levels, and minimal or no emissions. This study conducts a finite physical dimensions thermodynamic analysis (FPDT) on a gamma-type double-piston cylinder engine and compares the results with other isothermal models and experimental data. The current model’s results align closely with those of other thermodynamic models

A novel close loop analysis of gamma prototype stirling engine

Air pollution is greatly influenced by the emissions generated by automotive engines, making it a pressing concern. To address this issue, a considerable amount of research is currently devoted to recovering waste heat from these engines. A gamma-type Stirling engine has been meticulously chosen to achieve this specific objective. This study elucidates a new isothermal method that effectively analyses Stirling engines. A set of differential equations is proficiently solved by employing the powerful MATLAB R2020a software. Remarkably, the simulation results obtained from this computational approach closely align with the experimental data, indicating the accuracy and reliability of the methodology. Furthermore, this research delves into the feasibility of employing the Stirling engine as a Combined Cooling, Heating and Power (CCHP) system, shedding light on its potential applications in various domains

Regenerated cellulose-based composite strengthened with post-consumer polyester garments

Polyester garments have an extensive availability nowadays. However, most post-consumer garments are burned and landfilled, leading to extreme pollution and significant waste of resources. Therefore, sustainably and economically recycling this post-consumer polyester (PCP) fabric waste for essential value-added products is meaningful and necessary. In this study, waste polyester fabrics obtained from PCP garments have been utilized in the development of composite materials. First, PCP fabric was dissolved in a methanol and sodium hydroxide solution. Then, the polyester paste was regenerated on regenerated cellulose-based fabric (viscose), constructing a viscose-based composite. The physical, thermal, chemical, morphological, and mechanical properties were examined for the viscose and viscose-polyester (VP) composites. FTIR, XRD, SEM, and percent add-on confirmed the presence of polyester in the composite. In addition, an add-on percentage of 10.71, higher crystallinity of 55.20%, thermal stability, and about 21% higher tensile strength were observed. The results, as mentioned above, ensured that the PCP waste can be used as a matrix for composite materials

Design and modelling of MEMS resonators for an artificial basilar membrane

The human cochlea is undeniably one of the most amazing organs in the body. One of its most intriguing features is its unique capability to convert sound waves into electrical nerve impulses. Humans can generally perceive frequencies between 20 Hz and 20 kHz with their auditory systems. Several studies have been conducted on building an artificial basilar membrane for the human cochlea (cochlear biomodel). It is possible to mimic the active behavior of the basilar membrane using micro-electromechanical systems (MEMSs). This paper proposes an array of MEMS bridge beams that are mechanically sensitive to the perceived audible frequency. They were designed to operate within the audible frequency range of bridge beams with 450 µm thickness and varying lengths between 200 µm and 2000 µm. As for the materials for the bridge beam structures, molybdenum (Mo), platinum (Pt), chromium (Cr) and gold (Au) have been considered. For the cochlear biomodel, gold has proven to be the best material, closely mimicking the basilar membrane, based on finite-element (FE) and lumped-element (LE) models