Abstract The firehose instability (FHI) has been studied by kinetic approach with Kappa distribution function in auroral acceleration region of the magnetosphere. The combined effect of temperature anisotropy for ions, electrons, and dust particles, which are responsible to drive firehose instability, is modeled through non-maxwellian Kappa distribution function. The kinetic Vlasove-Maxwell equations are used to describe the dispersion nature of the firehose mode. In the high beta homogenous plasma by applying Kappa distribution function, dispersion relation, growth rate and growth length have been investigated. The effect of spectral index kappa have been studied on FHI. The range of beta parameter and anisotropy is analyzed at different fixed value of kappa index. It is considered that the instability is propagating along the background guiding magnetic field. The interpretation of the analytical results, have been done on the plasma parameters of auroral acceleration region, which is a part of the earth's magnetosphere. The result and analysis may be extended to multi component plasma and in low beta plasma also.
Laser marking is one of the operations performed by laser with an aim to identify products, components, etc., so that they can be easily traced with information. The multi diode pumped fibre laser with ytterbium doped as a lasing medium, was used to mark a circular shaped image. The paper aimed to study the influence of process parameters such as laser power, pulse frequency, scanning speed, duty cycle and transverse feed on responses such as mark intensity, circularity and surface roughness value (Ra, μm). The range of process parameters involved were transverse feed of 4-14 μm per laser stroke, laser power of 7.5-17.5 W, pulse frequency of 50-60 kHz, duty cycle of 20-40% and scanning speed of 5-25 mm/s. Experimental work was carried out without the supply of assist gas pressure and laser marking process was done by scanning the fibre laser for single pass. Experimental results revealed that for better value of mark intensity, circularity and surface roughness value (Ra) of circular shaped marked image, the process parameters such as laser power of 12.5 watt (W), pulse frequency of 50 kHz, duty cycle of 30% and scanning speed of 5 mm/s should be selected.
Advanced polymer textile composites are characterised with high strength to weight ratio and tailored mechanical properties claiming their applications in advanced engineering sectors. The research work presented is focused on the development and characterisation of compressive behaviour of monolithic Kevlar and carbon-Kevlar hybrid fabric reinforced polymer composites (FRPCs). Vacuum-assisted resin transfer moulding process is used to cast the composite laminates. Results obtained present the effect of hybridisation of carbon yarns with Kevlar fabric, also compare the compression modulus and compressive strength of two fabrics along longitudinal axes. Fabrics with different weaving patterns, namely plain and twill are considered for reinforcement to experimentally investigate the role of weaving pattern plays in governing the mechanical strength of textile composite. FE model is generated to numerically simulate the compression loading behaviour of composites. Simulation results of longitudinal compression of carbon-Kevlar hybrid fabric composite show a good agreement with experimental results.
Machining of low machinable non conducting engineering materials like borosilicate glass has imposed challenges in the manufacturing of micro devices like microfluidics, MEMS etc. Electrochemical discharge machining (ECDM), a hybrid processes of electric discharge machining (EDM) and electro chemical machining (ECM), emerging as a potential method to address the low machinability problems. In the present work the influence of helical tungsten carbide tools of varying diameter assisted with high speed tool rotation was adopted to improve machining performance in terms of on the material removal rate (MRR), heat affected zone (HAZ), radial over cut (ROC), tool wear rate (TWR) and depth of machining (DOM). It was found that the hydrodynamic region was more predominant with tool diameters 600 μm, 700 μm and at 2,500 rpm and resulted to a low machining depth. Smaller diameter tools assisted with rotational was found significant influence on the machining responses.
Micro-milling can generate micro molds involving complex shapes rapidly as compared to other micro machining techniques. Researchers thoroughly investigated different aspects of micro-milling with straight tool paths. This paper investigates the effect of tool paths on cutting forces, tool wear and top burrs generated in micro-milling using straight and circular tool paths for micro channel fabrication. Micro-milling experiments were carried out to understand the effect of tool paths at two levels of cutting parameter values. It was observed that the tool wear rate in micro-milling along a circular tool path is more compared to that of straight tool path. Consequently, the cutting forces, top burrs and surface roughness were found to be more in circular tool paths. The flank wear rate in micro-milling along the circular tool path was estimated to be 70.9 μm/m and 84.1 μm/m for lower and higher levels of cutting parameters, respectively. However, the flank wear rate along the straight tool path was 57.24 μm/m and 62.8 μm/m for lower and higher levels of cutting parameters, respectively.
The present study focused on the mechanical properties of stir cast Al 6063/Al2O3 (alumina) reinforced metal matrix composites. Aluminum-alumina composites are used in various industries including fabrication, aerospace, automobile sectors, etc. The properties like corrosion resistance, low density, and high modulus of elasticity, higher thermal, and electrical conductivity make them the best choice for its applications in various industries (Prasad, 2004). The present work focus on the hardness of Al 6063/Al2O3 (alumina) reinforced metal matrix composites by varying the percentage of the reinforced element alumina in the base matrix alloy Al 6063, stirring speed and stirring time (Kok, 2005). The thickness of the sample was taken 10 mm, width 30 mm and length 100 mm. Nine samples were prepared by varying the percentage of alumina 2%, 4%, 6% (wt %), stirring speed of 800, 1000 and 1200 (Rpm) and stirring time of 5, 10, 15 (minutes). In this experiment work various works has been reviewed in which lower concentration of alumina was taken to analyse the effect on the response factor, that's why lower even concentration of alumina was taken. It was shown from the experiment that the hardness value increases with the increase in reinforcement percentage but after that, there was a decrease in hardness value.
In recent years, material ablation at solid-solid interface by laser micromachining technique is emerging as a novel method for synthesising nanoparticles. It generates chemically pure fine crystalline particles compared to traditional methods. Moreover, it enables higher confinement of plume, thereby favouring nanoparticle growth compared to liquid-solid interface and gas-solid interface. This paper demonstrates the novel method of synthesising crystalline nanoparticles of titanium dioxide (TiO2), zinc oxide (ZnO), and graphite by laser ablation at solid-solid interface. The interface was maintained by preparing transparent ice on the target placed in a glass vessel. The size of synthesised nanoparticles is in the range of 1.5 nm to 5 nm for TiO2, 100 nm to 500 nm for graphite, and 2-10 μm for ZnO (agglomerated). From the observations, it can be inferred that the process employed gives an improved rate of synthesising crystalline nanoparticles.
This paper targeted the design and stress comparison of a small-scale wind turbine blade which was constructed for the specific environmental conditions of the small rural village in Ethiopia. Firstly, the blade was designed from the characteristic of aerodynamic performance. Secondly, modelling and stress analysis of the windmills was conducted which is very significant for the further design and application of wind turbines. The material was epoxy-GFRP composite. The orthotropic mechanical properties of woven fibre epoxy polymer composite were created (ASTM D1683) with help of Autodesk Helius Composite V.16 software. The tensile and flexural testing specimens were fabricated by D3039M-17 and D7264M-15, respectively. Load, displacement, and modulus were investigated using UTM. Based on the parameters of the airfoil, the three-dimension and the assembly models of blades were mounted with the SOLIDWORK-V.16. Then the models were imported into ANSYS-V.15 WORKBENCH software for analysis. The displacement, Von Misses, and principal stress effects were determined.
The present study investigates various mechanical properties of aluminium matrix composites (AMCs) reinforced with aluminium oxide and rice husk ash. Stir casting method was applied to produce composites reinforced with different amounts (2 wt. %, 4 wt. %, 6 wt. % and 8 wt. %) of rice husk ash particles and aluminium oxide. Mechanical properties such as micro hardness, tensile strength and wear rate have been examined. Pin-on disc apparatus is used for wear characteristics of the composites at load of 9.8 N, sliding velocity 1.5 m/s and sliding distance of 1,000 metres. Tensile test is performed on the universal testing machine. SEM and EDS were conducted to evaluate the chemical composition of RHA. It has been demonstrated that the increase in reinforcement content shows significant increase in mechanical properties of AMC. Further, rice husk ash shows better results in mechanical properties as well as in wear characteristics comparatively to aluminium oxide.
Green supply chain factors and practices have gained increasing attention from the customers, businesses, and academicians for improving overall business sustainability. Because customers also value reliable business performance in terms of product and services availability, supply chains must be resilient for their sustainability and business continuity. Supply chain (SC) operations are exposed to various internal disasters initiated by humans and external disasters from natural calamity and terrorist activities. This research designs a SC model that incorporates green approach-based product design, procurement, manufacturing, and distribution management. The model also includes resilience planning for these supply chain steps. The objective of the research is to improve overall sustainability performance of the supply chain by integrating contributions of green factors and resilient criteria in all phases of a supply chain. A numerical example illustrates applicability of the model, overall approach of the study, and managerial insights.
Titanium alloys have found growing applications in aerospace, biomedical and marine industry.However, extreme hardness and strength cause difficulty in machining of titanium alloys.This is further complicated by the requirements of micro-features on hard to machine alloys.Micro-electro discharge machining (micro-EDM) is being investigated to match the requirement.However, slower removal rates and thermal effects are the issues in thermal erosion-based EDM process.In this work, we have investigated the efficacy of using carbon nanofibres (CNFs) mixed with the dielectric fluid for micro-machining of Ti-6Al-4V using micro-EDM.It is observed that the addition of CNFs not only improves electro-discharge frequency, material removal rate but also improves the surface roughness.Added nanofibres lowered the material migration and increased spark gap.We noted a significant influence of mixing CNFs in the dielectric fluid for enhancing machining performance characteristics in μEDM during micro hole generation on Ti-6Al-4V alloy.
In conceptual design, virtual reality assurances to be a natural, cost-effective, and creative method. Representation of the model in the virtual reality environment is a significant step. In the virtual environment, while representing the model, it should behave realistically. Several techniques like implicit, tessellated, parametric representations are available for representing the models. In the present work, the model is created from data of point cloud using volumetric self-organising feature map algorithm. The virtual model generation from point cloud data helps in the secure exchange of database between commercially available computer-aided design (CAD) software. 3D B-splines have been selected to represent the virtual model. A three-dimensional virtual model has been generated from the data of point cloud. For efficient collision detection, surfaces have been also extracted from the three-dimensional model by considering the alternative values of u, v, w parameters as 0 and 1. Anyone of the six extracted surfaces can be used for collision detection. The results showed that the extraction of surfaces is beneficial for efficient collision detection.
Abrasive waterjet turning (AWJT) is an advanced machining process that could be used for turning cylindrical workpieces with the advantages of low vertical forces and negligible thermal distortion. Radial-mode AWJT is characterised by better utilisation of jet energy and high material removal rate. However, the prediction of depth of cut (DOC) is difficult due to the interaction of several process parameters. In this paper, a new finite element (FE) model was developed to predict the DOC in radial-mode AWJT. The workpiece material is AISI 4340 alloy steel and it is modelled with Johnson-Cook (JC) constitutive model. Two AWJT parameters: waterjet pressure and abrasive flow rate, were considered in the FE model with three levels for each parameter. A full factorial design was selected to evaluate the combined effect of these independent parameters. The resulting crater profile was utilised to estimate the DOC at each parameter combination. In order to evaluate the model accuracy, the DOC results were compared with published experimental data from the literature at the same AWJT conditions. The comparison showed a good agreement between the FE results and the published experimental results.
Electric discharge machining (EDM) is renowned for machining intricate geometries of hard materials. The dielectric fluid is reflected to be the key indicator of sustainability. Conventional hydrocarbon dielectrics are considered to be toxic and emitting harmful aerosol emissions leading to environmental pollution. The bio-based dielectric has comparable features to conventional dielectric and thus can be replaced. The present analysis is projecting the new green dielectric fluids, named pongamia green dielectric (GD1) and neem green dielectric (GD2) for sustainable EDM of 2507 super duplex stainless steel. Material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) are measured by varying pulse-on time (Ton), pulse-off time (Toff), peak current (Ip), voltage (v) and inter-electrode gap (IEG) in Taguchi's L27 experiments. GD1 and GD2 have outperformed conventional dielectric by 18.45% and 42.08% in terms of MRR, 5.9%, and 7.5% in terms of SR.
The minimum quantity lubrication (MQL) is prominent among the environmentally friendly machining techniques. Localised cooling and lubrication at multiple locations in the cutting zone is the latest development to improve efficacy and further trim down the consumption of metalworking fluid. The paper consolidates the strategies to use the MQL cutting fluids at the specific locations, vis-à-vis rake face, flank face and back of the chip. A critical analysis is made on cutting fluids, cooling strategies, process parameters, and their effect on quality. The latest developments and future directions in the framework of the hybrid lubrication method, hybrid cutting fluid and numerical modelling are presented.
Turning operation is one of the most widely used machining processes in manufacturing industries wherein optimisation of process parameters is the most critical aspect within the operational constraints. In this paper, finite element simulations have been carried out for dry turning of Al6061 alloy with uncoated tungsten carbide inserts to predict the performance of machining. Thus, the effect of process parameters such as cutting speed, feed rate and depth of cut on response variables such as cutting temperature, cutting energy, effective stress, material removal rate and tool life have been studied by employing Taguchi L25 orthogonal array. Grey relational analysis has been further used to convert multi responses parameters to a single response for optimising the process parameters using particle swarm optimisation. The results of the study indicated that the cutting speed of 40 m/min, feed rate of 0.04 mm/rev and 0.5 mm depth of cut provides better machining performance based on the application of simulation approach leading to time saving and efficient utilisation of resources.
Micro-drilling of fibre-reinforced composites is an inevitable machining operation in the different sectors namely biomedical, aerospace, and automobile, to name a few. However, the damages induced during micro-drilling of fibre-reinforced composites due to the anisotropic and heterogeneous nature of the composite is an observable impediment. Thus, in this research endeavour, the micro-drilling behaviour of green composite composed of bamboo fibre and poly(lactic) acid (PLA) was experimentally investigated. The intrinsic effect of the process parameters namely drill diameter (300, 400, and 500 μm), feed (1, 1.5, and 2 mm/min), and tool speed (300, 400, and 500 RPM) on the induced delamination both at the entry and exit side of the hole was studied by performing response surface methodology (RSM). The drill diameter was found to be the most significant parameter affecting the induced delamination. Delamination was found to be increased with the drill diameter and decreased with the tool speed. The lower level of drill diameter (300 μm), higher level of feed (2 mm/min), and higher level of tool speed (500 RPM) was found to be the optimised parametric setting to obtain the lower value of delamination factor. The optimised delamination factors at the entry and exit sides of the hole were found to be 1.318 and 1.359.
Sustainable manufacturing provides a balance between manufacturing and the environment. The purpose of this paper is to acquaint the readers about the research trends in sustainable manufacturing related literature based on the data collected from Web of Science core collection and Scopus database using bibliometric analysis and visualisation network analysis. Different analysis has been done like trend analysis, author analysis, discipline-wise analysis, source analysis, country analysis, institution-wise analysis and cluster analysis of author keywords. This study demonstrates that the focus on sustainable manufacturing research field has been increased after 2008 and has a good scope in different fields. Co-citation analysis of countries by the name of the author shows the collaboration, contribution, and sharing of knowledge between the countries. A list of top 30 highly influential papers is also assessed from both databases. The results analysis also reveals a promising future research direction for researchers in the area of sustainable manufacturing.
