Experimental and numerical prediction of extrusion load at different lubricating conditions of aluminium 6063 alloy in backward cup extrusion

In the present research work using a backward cup extrusion (BCE) die profile, different lubricating conditions on aluminum alloy AA6063 have been experimentally and numerically investigated to predict the extrusion load. It was obvious that due to an increase in applications of the extrusion process, many researchers have worked on the extrusion process using different methods to achieve their aims. This experiment was conducted with three different lubricants namely: Castor oil, Palm Oil and tropical coconut oil; as well as without lubricants. Different lubricating conditions were employed of varying strain rates ranges from 1.5×10-3s-1, 2.0×10-3s-1, 2.5×10-3s-1, and 3.0×10-3s-1; Numerical analysis and simulation for dry and lubricated conditions during extrusion load were also performed using DEFORM 3D software. The results show that prediction extrusion load increases with increasing strain rates. The maximum extrusion load was found to be higher for extrusion without lubricants. In all cases of strain rate, palm oil showed a lower extrusion load compared to the other lubricants. Castor oil indicated the highest extrusion load when the experiment was carried out using lubrication. There was a consistent agreement between the result gotten from the experiment and simulation results of the extrusion load-strike curve.Peer reviewedFinal Published versio

EXPERIMENTAL AND THEORETICAL INVESTIGATION OF TENSILE STRESS DISTRIBUTION DURING ALUMINIUM WIRE DRAWING

Wire drawing, has received a wide range of applications in the production. A wide number of cable applications demand that the cable survive high tensile loading. This works entails experimental and theoretical investigation of tensile stress distribution during aluminium wire drawing. The initial Aluminium rod used in this work was, 9.50mm with density of 2700kg/m3 , young’s modulus of (7x1010 Pa), Poisson’s ratio (0.33), Yield stress in simple tension (21.7 × 106Pa), which was later drawn to different diameter as required and tensile testing was carried out on each required diameter. In this work, tensile stress distribution in the drawing process is determined via experimental and analytical method. A free body equilibrium method is used to obtain the equations that dictate the drawing phenomenon. The result obtained by experiment is compared with improved model and also with other solutions found in the literature about these themes, particularly, with Rogas solutions in slab method case. There is high degree of similarity between the result obtained experimentally and the simulation of improved model but there is a wide gap when compared experimental result with simulation of classical slab method. Thus, the result of the study will be of great benefit to industries that make use of aluminium wire as electrical wiring, cables, spokes for wheels, stringed musical instruments, paper clips and tension-loaded structural components and also automotive sector. This will help them determining the extent of tensile loading that the aluminium wires their working on can withstand before failure can occur

Impact of rGO-coated PEEK and lattice on bone implant

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).The composite coating can effectively inhibit bacterial proliferation and promote the expression of bone-building genes in-vitro. Therefore, a novel production was used to produce poly-ether-ether-ketone, and reduced graphene oxide (PEEK-rGO) scaffolds with ratios of 1–3%, combining a different lattice for a bone implant. An inexpensive method was developed to prepare the new coatings on the PEEK scaffold with reduced graphene oxide (rGO). Mechanical testing, data analysis and cell culture tests for in-vitro biocompatibility scaffold characterisation for the PEEK composite were conducted. Novel computation microanalysis of four-dimensional (4D) printing of microstructure of PEEK-rGO concerning the grain size and three dimensional (3D) morphology was influenced by furrow segmentation of grains cell growth on the composite, which was reduced from an average of 216–155 grains and increased to 253 grains on the last day. The proposed spherical nanoparticles cell grew with time after dispersed PEEK nanoparticles in calcium hydroxyapatite (cHAp) grains. Also, the mechanical tests were carried out to validate the strength of the new composites and compare them to that of a natural bone. The established 3D-printed PEEK composite scaffolds significantly exhibited the potential of bone implants for biomimetic heterogeneous bone repair.Peer reviewedFinal Published versio

Shape memory polymer review for flexible artificial intelligence materials of biomedical

The self-healing and biocompatibility of polymer composites for biomedicine have made them a preferred approach for small-scale tissue engineering elements. By moving from static to dynamic pressure, 4D printing simulates the natural physical-mechanical changes of living tissue over time. A promising new platform with excellent controllability actuation is required to enhance the significance of 4D printing for biological applications. This study systematically analyses current 4D printing technologies for the flexible fabrication of artificial intelligence (AIM) materials. In addition, many potential applications of flexible 4D printing in composite biological engineering are thoroughly investigated. We found that knowledge about this new category of flexible AIM composites is relatively limited, and the potential for practical applications has not yet been demonstrated. Finally, we discuss the problems and limitations of flexible 4D printing technology, AIM, and future approaches and applications.</p

Entropy Generation of Graphene Nanoplatelets in Micro and Mini Channels: Nanofluid Flow in Automotive Cooling Applications

The present study examines the entropy generation of graphene nanoplatelet (GnP) suspended in different basefluids, theoretically. GnP in water (W), ethylene glycol (EG) and ethylene glycol- water (EGW, 1:1) was examined under laminar flow state in a unit length mini and micro-channel of 3mm and 0.05mm diameter. The coefficient of conductivity (Ck) and viscosity (Cμ) of the nanofluid were determined from experimental analysis and their order of magnitude were established for analysis of entropy generation in mini and micro-channels. Entropy generation by fluid friction (Sgen, ff) in the channels containing EG was higher than with W and EGW by 75.6% and 79.9%, respectively. Thermal irreversibility (Sgen, th) of W was lower by132.9% and 58.2% compared to EG and EGW. Sgen,th in all the fluids decreased with increased solid volume fraction in minichannels, while, Sgen,ff increased with increase in volume fraction for micro-channels. Total entropy generation (Sgen, tot) of water was lower by 75.6% and higher by 64.8% compared to EG and EGW, respectively in a micro-channel, whereas Sgen, tot of water was lower by 123.7% and 38.4% compared to EG and EGW, respectively. As GnP volume fraction was increased in the basefluids, entropy generation ratio decreased, highlighting the positive influence of thermal properties of the nanofluid. A lower Bejan number for water (Bew), 36.8% and 358.9% were observed compared to EG and EGW in microchannel, whereas Bew was lower by 3.8% and 13.8% when compared to EG and EGW nanofluids in the mini channel

Modeling and Simulation of Wave load on Periodic Support for Isolation system of offshore platform.

The wave-induced dynamic load is one of the most important excitations to be dealt with in the design of offshore structures and the platforms. In order to perform a reliable design of an offshore structure, it is important to obtain an exact evaluation of its dynamic response to wave load but also to examine the ways of reducing the response. The work analyzed the effects of wave load on periodic support of isolation system of jacket offshore platform. The platform considered herein as an example to examine the effectiveness of the proposed vibration control strategy for offshore structures. In this section, a parametric study for the jacket offshore platform with installation of the periodic support to enhance isolation system due to its attenuations ability over broad frequencies and the effects of wave load on offshore jacket platforms installed with energy dissipation devices such as periodic support were presented. The offshore jacket platforms are modeled as multi-degrees-of-freedom and the general equation for fluid forces acting on a cylinder, considering the relative motion of the body in the fluid as per the Morison’s equation was applied to form the basis of modeling of the wave load and supports. The analyzes of the effects of wave load on the offshore platform especially with periodic support was considered due to its attenuations over broad frequencies. It could be realized from the result that increase in waves load varies the increase in frequency domain of the system which enhances subjection to vibration

A short review on queuing theory as a deterministic tool in sustainable telecommunication system

Telecommunication mechanisms have been conceptualized simply as links between two points to send signals. Telecommunication networks are, at present, characterized by clusters of nodes, interconnecting nodes where information is processed and correctly addressed to the output links. The transmission of messages was assisted by the first telecommunication networks for telegraphy. Mobile phone networks were then built to build a physical call circuit set up to connect the source and destination for the entire duration of the conversation. The networks of today are digital and are focused on the dissemination of signals arranged in blocks, called packets, which are either routed independently along the nodes or transmitted from source to destination through a virtual path. On the basis of the network hierarchy, transmission media are usually distinguished. When a customer of a company has any kind of issue, their first contact with the company is the call center. They give feedback of their issues to the call center and the call center’s quality service is so important because the service would determine if the customer’s issue is resolved and if the customer would continue to do business with the company afterwards. Deciding an optimum number of operators using key performance index is an important factor in optimizing a communication system. Research carried out show that this optimization can be made using queuing theory approach. A practical application of optimizing a call center using stochastic queuing approach is studied in this review. From the research, the optimal number of operators for the call center was determined for various peak periods considering four performance index measures. The information gathered shown the importance of using queuing theory model as a deterministic tool for optimizing a communication system

Study of the Performances of Nano-Case Treatment Cutting Tools on Carbon Steel Work Material during Turning Operation

The degree of holding temperature and time play a major role in nano-case treatment of cutting tools which immensely contributed to its performance during machining operation. The objective of this research work is to carryout comparative study of performance of nano-case treatment tools developed using low and medium carbon steel as work piece. Turning operation was carried out under two different categories with specific work piece on universal lathe machine using HSS cutting tools 100 mm x 12mm x 12mm that has been nano-case treated under varying conditions of temperatures and timeof 800,850, 900, 950oC and 60, 90, 120 mins respectively. The turning parameters used in evaluating this experiment were cutting speed of 270, 380 and 560mm/min, feed rate of 0.15, 0.20 and 0.25 mm/min, depth of cut of 2mm, work piece diameter of 25mm and rake angle of 7o each at three levels. The results of comparative study of their performances revealed that the timespent in the machining of low carbon steel material at a minimum temperature and time of800°C, 60 mins were1.50, 2.17 mins while at maximum temperature and time of 950°C , 120 mins were 1.19, 2.02 mins. It was also observed that at a corresponding constant speed of 270,380 and 560mm/min at higher temperature and time, a relative increased in the length of cut were observed. Critical observation of the result showed that at higher case hardening temperature and time (950°C/120mins), the HSS cutting tool gave a better performance as lesser time was consumed during the turning operation