Experimental Characterization of Electrical Discharge Machining of Aluminum 6061 T6 Alloy using Different Dielectrics

Electrical discharge machining is a non-traditional machining method broadly employed in industries for machining of parts that have typical profiles and require great accuracy. This paper investigates the effects of electrical parameters: pulse-on-time and current on three performance measures (material removal rate, microstructures and electrode wear rate), using distilled water and kerosene as dielectrics. A comparison between dielectrics for the machining of aluminum 6061 T6 alloy material in terms of performance measures was performed. Aluminum 6061 T6 alloy material was selected, because of its growing use in the automotive and aerospace industrial sectors. The experimental sequence was designed using Taguchi technique of L9 orthogonal array by changing three levels of pulse-on-time and current, and test runs were performed separately for each dielectric. The results obtained show that greater electrode wear rate (EWR) and higher material removal rate (MRR) were achieved with distilled water when compared with kerosene. These greater EWR and MRR responses can be attributed to the early breakage of the weak oxide and carbide layers formed on the tool and alloy material surfaces, respectively. The innovative contributions of this study include, but are not limited to, the possibility of machining of aluminum 6061 T6 alloy with graphite electrode to enhance machinability and fast cutting rate employing two different dielectrics.Peer reviewe

A Human Factors Perspective on Helicopter Human External Loads

Human external loads (HEL) refer to operations where humans are transported while suspended below a helicopter. HEL operations are often required to access remote work sites, to access power lines in need of maintenance and repair, for transport of offshore ship captains, and for rescue operations. This paper reports a human factors investigation of HEL operations and the devices used to secure HELs involved in work (non-rescue) activities. The goal of this investigation was to determine if HEL operations pose a significant safety hazard. Specifically, the paper describes the various devices used to secure HELs, the accident history associated with HELs, and human factors recommendations for the regulation of HEL devices and operations. Review of 616 helicopter accident reports revealed that only 1.5% of the accidents occurred during HEL operations and only 0.5% were directly attributable to the presence of an HEL.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Multi-objective optimisation for minimum quantity lubrication assisted milling process based on hybrid response surface methodology and multi-objective genetic algorithm

© 2019 by SAGE Publications Ltd.Parametric modelling and optimisation play an important role in choosing the best or optimal cutting conditions and parameters during machining to achieve the desirable results. However, analysis of optimisation of minimum quantity lubrication–assisted milling process has not been addressed in detail. Minimum quantity lubrication method is very effective for cost reduction and promotes green machining. Hence, this article focuses on minimum quantity lubrication–assisted milling machining parameters on AISI 1045 material surface roughness and power consumption. A novel low-cost power measurement system is developed to measure the power consumption. A predictive mathematical model is developed for surface roughness and power consumption. The effects of minimum quantity lubrication and machining parameters are examined to determine the optimum conditions with minimum surface roughness and minimum power consumption. Empirical models are developed to predict surface roughness and power of machine tool effectively and accurately using response surface methodology and multi-objective optimisation genetic algorithm. Comparison of results obtained from response surface methodology and multi-objective optimisation genetic algorithm depict that both measured and predicted values have a close agreement. This model could be helpful to select the best combination of end-milling machining parameters to save power consumption and time, consequently, increasing both productivity and profitability.Peer reviewedFinal Published versio

Hen’s egg white hypersensitivity among a group of Egyptian atopic children

Background: Egg allergy is potentially life-threatening. The prevalenceof egg allergy in Egypt is still unclear. This study is to evaluate thefrequency of egg hypersensitivity in a group of Egyptian atopic children.Methods: Eighty allergic children were enrolled, each is subjected toclinical evaluation, skin prick testing (SPT) using a commercial eggwhite extract, and serum egg white specific IgE (SpIgE) estimation. Sixpatients with suspected egg allergy consent to perform open oral eggchallenge. Results: Twenty-eight patients had history of exacerbation oftheir allergic diseases upon exposure to egg white, of these patients, 8had negative SPT and serum egg white SpIgE. SPT was positive in 25(31.2%) patients, of these patients, 3 (4%) were +3, 22 (28%) were +2,of whom 5 patients tolerate eggs without adverse effects. Serum eggwhite SpIgE was positive in 19 (24%) patients with a mean of 0.81 IU/ml(range: 0.35-4.52 IU/ML). Egg white allergy based on positive history,positive SPT and/or egg white SpIgE was detected in 23 (28.8%)patients. Open oral egg challenge was positive in one patient withpositive history but negative tests giving an overall frequency of eggallergy of 30 % (n=24).While egg white SpIgE did not correlate with theages, positive SPT was significantly more frequent among youngerpatients (t= 1.7, p=0.02). Egg sensitization and allergy did not affect theseverity of asthma (p > 0.05). Conclusion: Although positive SPT/ serumspecific IgE to eggs are good tools for diagnosis, oral food challengeremains the gold standard in suspected cases. Further wide-scale studiesare needed to outline the real prevalence of egg allergy in Egypt.Keywords: Egg allergy; children; skin prick test

Effectiveness of 2-D Views for 6-D Robotics Simulation Maneuvers

This study examined operator performance on 6-D robotics simulation maneuvers using a single 2-D view of the robot arm. The BORIS simulator, developed by NASA to support Generic Robotics Training, was used to present four “fly-to” tasks with views representing combinations of good and poor control-display movement compatibility and perceptual quality. Translational (x, y, z) and rotational (pitch, yaw, roll) accuracies were used to assess performance. A significant interaction between movement compatibility and perceptual quality was found for both the overall translational and y accuracy measures (p = 0.0289 and p = 0.0155, respectively). This interaction appeared to indicate that performance was hindered only if both factors were poor. Perceptual quality significantly affected the z accuracy and pitch accuracy measures (p = 0.0461 and p = 0.0429, respectively) with the views identified as poor perceptual quality actually yielding better performance. These results suggest that performance on a 6-D robotics maneuver is not necessarily hindered by using only a 2-D view. If a single view cannot simultaneously provide both good movement compatibility and good perceptual quality, the results suggest that either one is sufficient with respect to overall translational accuracy.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Clinical Assessment of Electromagnetic Compatibility of Hearing Aids and Digital Wireless Phones

Research studies have shown that digital wireless phones interact with some hearing aids, creating a buzzing noise that may reduce speech intelligibility. Interference signals for three phone technologies were generated at five sound pressure levels (35 dB, 45 dB, 55 dB, 65 dB, and 75 dB) and mixed with speech at 65 dB SPL to test the speech intelligibility of 24 hearing-impaired people. A “No Noise” condition was also tested. Scores for the TDMA-217 Hz phone signal at low speech-to-noise ratios (<10 dB) were significantly lower than those for CDMA and TDMA-50 Hz at the same level. The CDMA and TDMA-50 Hz phone signals had a similar effect on speech intelligibility. Speech intelligibility scores at speech-to-noise ratios of 20 dB and 30 dB were similar to those for the “No Noise” condition. The articulation index represented the best index for predicting the impact of wireless phone interference on speech intelligibility.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

An effective uncertainty based framework for sustainable industrial product-service system transformation

Industrial Product-Service Systems (IPS2) can provide insights to enhance the environmental sustainability and lower environmental impact. However, its successful realisation for preventing the production of waste, while increasing efficiencies in the uses of energy and human capital remains a highly convoluted problem. This research article aims to address this issue by presenting an innovative uncertainty-based framework that can be used to assist in achieving increased sustainability within the context of IPS2. The developed framework explains the drivers for decision-making and cost to enable sustainability improvements in transforming to industrial services. This is based on academic literature, and multiple case studies of seven industrial companies with over 30 h of semi-structured interviews. The validation of the framework through two case studies demonstrates that uncertainty management can enable resource efficiency and offer sustainable transformation to service provision

Comprehensive Study on Tool Wear During Machining of Fibre-Reinforced Polymeric Composites

© 2021 Springer-Verlag. The final publication is available at Springer via https://dx.doi.org/10.1007/978-981-33-4153-1.The use of fibre reinforced polymeric (FRP) composites has increased rapidly, especially in many manufacturing (aerospace, automobile and construction) industries. The machining of composite materials is an important manufacturing process. It has attracted several studies over the last decades. Tool wear is a key factor that contributes to the cost of the machining process annually. It occurs due to sudden geometrical damage, frictional force and temperature rise at the tool-work interaction region. Moreover, tool wear is an inevitable, gradual and complex phenomenon. It often causes machined-induced damage on the workpiece/FRP composite materials. Considering the geometry of drill, tool wear may occur at the flank face, rake face and/or cutting edge. There are several factors affecting the tool wear. These include, but are not limited to, drilling parameters and environments/conditions, drill/tool materials and geometries, FRP composite compositions and machining techniques. Hence, this chapter focuses on drilling parameters, tool materials and geometries, drilling environments, types of tool wear, mechanisms of tool wear and methods of measurement of wear, effects of wear on machining of composite materials and preventive measures against rapid drill wear. Conclusively, some future perspectives or outlooks concerning the use of drill tools and their associated wears are elucidated, especially with the advancement in science and technology.Peer reviewedFinal Accepted Versio

A systems engineering study of integration reverse vending machines into the waste management system of Kazakhstan

This study aimed to conduct a systems engineering investigation for the integration of reverse vending machines (RVM) into the waste management system of Kazakhstan. By conducting a wide-scale survey among the general public, the study was able to identify the underlining reasons for low recycling rate, the awareness and willingness of the public to engage with RVMs, and incentives that would motivate them. Survey results also allowed identifying the customer (user) requirements and helped to design the house of quality (HoQ) for further evaluation of potential RVM functionality. The proposed system model and functional flow block diagram (FFBD) were developed for an RVM considering identified customer requirements. Finally, risk analysis of RVM integration to the waste management system was carried out, and mitigation measures were proposed