Browsing by Author "Saxena, Prateek"
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Item Open Access Energy resilient foundries: the “Small is beautiful” projects(Springer, 2022-02-05) Jolly, Mark R.; Salonitis, Konstantinos; Pagone, Emanuele; Papanikolaou, Michail; Saxena, PrateekApplying the concept of “small is beautiful” into a conservative relatively low technology manufacturing sector where the “economies of scale” argument has been used to build ever more so-called efficient process lines is a major challenge. The energy efficiency of the casting process has only been investigated in a limited fashion. The two “Small is Beautiful” projects aimed to introduce a new concept into foundries with regards to the use of their resources. The new philosophy, “small is beautiful”, starts by encouraging the use of high-quality feedstock, only melting what is required and only when it is required. Recycling of internal scrap is not necessarily acceptable but an aim for higher yields is. Applying counter gravity casting methods to improve yield and give enhanced quality is encouraged as is the recovery of low-grade heat from solidification. The present paper discusses the research undertaken and the key findings from the two projects.Item Open Access Environmental impact assessment of different strategies for the remanufacturing of user electronics(MDPI, 2022-03-24) Mann, Angad; Saxena, Prateek; Almanei, Mohammed; Okorie, Okechukwu; Salonitis, KonstantinosOver the years, the innovation and development of electrical and electronic equipment have been on a steep rise. Millions of electronics are being sold or discarded every year in the form of waste. Sustainable IT (Green IT or Circular Computing) is one of the most environment-friendly methods of reusing discarded or waste user electronics. The remanufacturing of a computer refers to the disassembly, repair, and upgrade of the original computer to give it a new life, along with a warranty that is as good as a new product. The goal of this work includes studying and assessing the total environmental impact of refurbishing a computer using life cycle assessment (LCA) integrated with discrete event simulation (DES), to compare two business models: (1) a case of centralized remanufacturing where the plants are in the Middle East, which is the hub for receiving waste electronics and distributing remanufactured goods; (2) a case of decentralized remanufacturing where the plants are situated in each continent for over a range of computer models. The environmental assessment was conducted using the openLCA software in combination with the WITNESS Horizon software for the DES. The results show that decentralized remanufacturing is a much more environmentally friendly option for the remanufacturing of computers, and the decentralized remanufacturing operation has a better throughput as well as efficiency, as compared to the centralized remanufacturing operation. The centralized remanufacturing scenario has a climate change impact of 1035.19 kg of CO2-Eq, as compared to the decentralized remanufacturing scenario with an impact of 816.12 kg of CO2-Eq. In terms of the impact on the marine life, decentralized remanufacturing was found to have 0.28 kg of N-Eq impact, as compared to centralized remanufacturing (0.22 kg of N-Eq). However, this does not give us a complete picture, as the environmental impact of the computer in its previous life remains unknown. Multi life cycle assessment is the assessment process that can be used to get a clearer picture of the ecological footprint of the computer during its multiple life cycles.Item Open Access Food 4.0: implementation of the augmented reality systems in the food industry(Elsevier, 2021-11-26) Jagtap, Sandeep; Saxena, Prateek; Salonitis, KonstantinosThe food industry is very resource-intensive and continuously under stakeholder’s scanner to address the impact of climate change, resource scarcity, ever-changing consumer demands and stringent legislations. It has resulted in the food industry adopting Industry 4.0 initiatives for changes. In this context, one of the key focus is on enhancing transparency through Augmented Reality (AR) experiences. Although the food industry has seen a rise in the adoption of Industry 4.0 technologies, the implementation of AR remains significantly low. This paper defines AR, its benefits, and challenges, and proposes a framework for AR implementation in the food industry.Item Open Access A framework for the improvement of frugal design practices(MDPI, 2020-09-17) Singh, Ravindra; Seniaray, Sumedha; Saxena, PrateekCurrent frugal design practice is focused on the cost reduction of the product. Despite advancements in the domain of frugal Innovation, it is not systematized to develop products for all sets of users, including marginalized society. Many design researchers and engineers now dedicate time and knowledge to producing practical solutions to enhance the quality of life of the marginal community. The approach currently being adopted restricts the development of products intended for all segments of the users. In this paper, cumulative frequency distribution analysis and the Relative Importance Index is used to identify the essential attributes, which contribute to delivering actual frugal products in terms of functionality, usability, performance, affordability, accessibility, aesthetics, and robustness. The framework is beneficial to eradicate the discriminatory effect of being labeled as “Jugaad” users.Item Open Access Materials selection and manufacturing of metal membranes for industrial applications(Elsevier, 2020-03-03) Singh, Himanshu; Saxena, Prateek; Puri, Y. M.In the current scenario, exploration of metal membranes has highly enhanced, and more efforts have been executed in its development and characterization. These breakthroughs have accelerated its applicability in the number of relevant sectors such as waste-water treatments, dairy processing’s, wineries, and biofuel refinement. This short letter inspects about recent findings and progress in the field of metal membranes, including its innovative manufacturing techniques and various applications, which have been reported in multiple research papers. The sintering technique is used generally for the preparation of metal membranes. Throughout this process, the resulting pore sizes are in the range of micrometers. Till now it is used for filtration of liquids to separate the solid particles. There is intense research work required for reducing the pore size of metal membranes using some cost-effective novel techniques, which will intensify its applicability in many green filtration technologies.Item Open Access A multi-level analysis of the implementation of industrial internet of things: challenges and future prospects(SSRN, 2020-10-26) Rajab, Sulaiman; Saxena, Prateek; Salonitis, KonstantinosIndustrial Internet of Things (IIoT) is still a new research area. The main emphasis of the IIoT literature is on identifying the challenges involved in implementation of the IIoT. This paper summarizes the literature on the barriers faced by any stakeholder aiming to adopt IIoT anywhere. After reviewing 31 empirical studies, three domains of factors have been identified, individual (skills, abilities and knowledge), institutional (organizational/management-related), and structural (technical and economic infrastructures). A total of eleven factors across the three dimensions have been extracted. The most important factors were the absence of human capital (limited individual soft and technical knowledge, skills and abilities), low information security experience leading to a high probability data leaks and high management resistance from employees and leaders. To strengthen information for successful IIoT implementation, this paper proposes the mandate of Security, Education, Training, and Awareness (SETA) initiatives for any stakeholder interested in IIoT adoption. A Causal loop diagram for the IIoT implementation is also developed and discussed in this workItem Open Access A new method for assessing the recyclability of powders within Powder Bed Fusion process(Elsevier, 2020-01-29) Gorji, Nima E.; Saxena, Prateek; Corfield, Martin R.; Clare, Adam; Rueff, Jean-Pascal; Bogan, Justin; González, Pierre G.M.; Snelgrove, Matthew; Hughes, Greg; O'Connor, Robert; Raghavendra, Ramesh; Brabazon, Dermot C.Recycling metallic powders used in the additive manufacturing (AM) process is essential for reducing the process cost, manufacturing time, energy consumption, and metallic waste. In this paper, the focus is on pore formation in recycled powder particles of stainless steel 316L during the selective laser melting process. We have introduced the concept of optimizing the powder bed's printing area in order to see the extent of the affected powders during the 3D-printing process. X-ray Computed Tomography (XCT) is used to characterize the pores inside the particles. The results from image processing of the tomography (rendered in 3D format) indicate a broader pore size distribution and a higher pore density in recycled powders compared to their virgin counterparts. To elucidate on this, the Electron Dispersion spectroscopy (EDX) analysis and Synchrotron-based Hard X-ray Photoelectron Spectroscopy (HAXPES) were performed to reveal the chemical composition distribution across the pore area and bulk of the recycled powder particles. Higher concentrations of Fe, Cr, and Ni were recorded on the interior wall of the pore in recycled particles and higher Mn, S and Si concentrations were recorded in the outer layer around the pore area and on the surface of the recycled particle. The pore formation in recycled powder is attributed to out-diffusion of Mn, S and Si to the outer surface as a result of the incident laser heat during the AM process due to higher electron affinity of such metallic elements to oxygenation. HAXPES analysis shows a higher MnO concentration around the pore area which impedes the in-diffusion of other elements into the bulk and thereby helps to creates a void. The inside wall of the pore area (dendrites), has a higher concentration of Fe and Cr oxide. We believe the higher pore density in recycled powders is due, at least in part to composition redistribution, promoted by laser heat during the AM process. Nanoindentation analyses on both virgin and recycled powder particles shows a lower hardness and higher effective modulus in the recycled powder particles attributed to the higher porosity in recycled powders.Item Open Access Non-destructive quality assessment of bio-engineering parts using Industrial Micro X-ray Computed Tomography: a review(Elsevier, 2021-01-01) Rathore, Jitendra Singh; Saxena, PrateekBio-engineering parts are widely used in hearing aid applications, dental applications, inhalation therapy blends, etc. Conventional tactile measurement techniques offer a limitation in the quality assessment of such parts due to the complex shape of the part and also due to their inability to measure internal features in a three-dimensional space. Industrial micro X-ray computed tomography (>μXCT) is a robust characterization technique designed to maintain part quality, facilitate precision manufacturing, and reduce material waste due to part rejection. This paper highlights the limitations and challenges of conventional measurement techniques in the assessment of the quality of bio-engineering components. Capabilities of μXCT are presented and its application in the bio-engineering sector is discussed in this work.Item Open Access Numerical simulation of heat distribution in RGO-contacted perovskite solar cells using COMSOL(Elsevier, 2020-01-06) Zandi, Soma; Saxena, Prateek; Gorji, Nima E.A 3D simulation of optical photogenreation, electrical characteristics, and thermal/heat distribution across the structure of a perovskite solar cell with a reduced graphene oxide (RGO) contact is presented. COMSOL Multiphysics package has been used to solve the coupled optical-electrical-thermal modules for this hybrid cell where the RGO added as the bottom electrode instead of a conventional metallic contact to enhance the heat dissipation towards a higher device stability. The Wave Optic module, Semiconductor module, and Heat Transfer in Solid module were coupled and solved for the proper input parameter values taken from relevant literature. The optical photogeneration, current-voltage characteristics, electric-field and the thermal maps of the cell are presented. The RGO contact doesn’t significantly impact on the optical and electrical output of the cell, but it accelerates the heat dissipation. The heat is mainly generated across the cell from the light absorption, Shockley-Read-Hall non-radiative recombination, and Joule heating. Compared to the cell with the Au electrode, the RGO contacted cell is showing a minimized heat accumulation and gradient at the bottom junction of the RGO/Spiro interface which promises a thermal stability of the cell. The nan-radiative and joule heat distribution also show a moderated density for the RGO contacted cell which are assigned to the high heat conductivity of the RGO layer compared to traditional metallic electrodes. Our simulations results are of the rarely presented thermal simulations for such devices and prove the superiority of graphene over plane metallic contacts for heat dissipation and thermodynamic aspect of a solar cell.Item Open Access Optimisation of the filling process in counter-gravity casting(Institute of Physics (IOP), 2020-06-12) Papanikolaou, Michail; Saxena, Prateek; Pagone, Emanuele; Salonitis, Konstantinos; Jolly, Mark R.Metal casting is one of the most energy-intensive manufacturing processes with limited resource efficiency. To solve the problem of high energy consumption, a novel counter-gravity casting process has been earlier introduced. This process also referred to as CRIMSON (Constrained Rapid Induction Melting Single Shot Up-Casting) makes use of melting metal, just enough to fill one mould cavity at a time. The molten metal is subsequently pushed into the mould with the help of a piston, using a counter-gravity controlled method. Although CRIMSON has been proven to be a highly efficient process with the potential to produce high quality final cast products, there is still room for optimisation of the process. The objective of this investigation is to estimate the optimum ingate velocity in order to ensure smooth filling of the mould and eventually reduce turbulence and the likelihood of defects in the final cast product. For this purpose, a computational framework integrating a CFD solver and an optimisation algorithm has been developed. The obtained results suggest that the optimised ingate velocity can contribute towards the smooth filling of the mould and effectively contribute towards the reduction of entrained air and surface defect concentration in the final cast product.Item Open Access A review on the progress and challenges of binder jet 3D printing of sand moulds for advanced casting(Elsevier, 2021-02-10) Sivarupan, Tharmalingam; Balasubramani, Nagasivamuni; Saxena, Prateek; Nagarajan, Devarajan; El Mansori, Mohamed; Salonitis, Konstantinos; Jolly, Mark R.; Dargusch, Matthew S.3D sand mould printing through binder jetting can solve many technical issues in casting including part consolidation, design of parts to optimise the consumption of materials and hazardous chemicals, and on-demand and any size part manufacturing near the customer. Incorporating artificial intelligence in optimising the design of moulds, printing process parameters, and solidification processes may help automate a production facility and reduce labour time. Elimination of hazardous chemicals from industrial use may be a challenge. Therefore, an alternative technology to fuse the sand particles during printing or an environmentally friendlier alternative option for the binders and other consumables should be utilised with the 3D sand printing process. Properties of parts produced using 3D printed sand moulds are better than the properties of parts produced using traditional casting due to this technology's benefits mentioned above. Though this technology is a supportive enabling technology for the traditional casting processes rather than a competing technology. This technology is causing a paradigm shift in casting design because of the mould geometries achievable using the sand moulds' additive manufacturing. This paper reviews the first twenty years of research and challenges in developing 3D sand printing as an innovation for sustainable manufacturing.Item Open Access Selective laser sintering induced residual stresses: precision measurement and prediction(MDPI, 2021-09-18) Impey, Susan A.; Saxena, Prateek; Salonitis, KonstantinosAdditive Manufacturing presents unique advantages over traditional manufacturing processes and has the potential to accelerate technical advancement across multiple sectors, permitting far greater freedom in design than conventional manufacturing. However, one barrier which blocks wide adoption is residual stresses, which could seriously affect the materials’ behaviour during and after production. Selective laser sintering (SLS), a process with high energy input to the workpiece material, induces high temperature gradients, further affecting the final residual stress distribution. Within the present paper, three different methods for the assessment of the residual stresses’ distribution are presented and compared: a non-destructive method based on neutron diffraction, a destructive method known as the contour method, and a theoretical approach based on Finite Element Analysis. The aim is to examine the suitability and reliability of the application of these methods in predicting residual stresses distribution in additive manufacturing-built partsItem Open Access Simulation of CZTSSe thin-film solar cells in COMSOL: three-dimensional optical, electrical, and thermal models(IEEE, 2020-06-19) Zandi, Soma; Saxena, Prateek; Razaghi, Mohammad; Gorji, Nima E.The Cu $_2$ ZnSnS $_x$ Se $_{4-x}$ (CZTSSe) thin-film solar cells have attracted the attention of researchers due to its earth-abundant composition containing Copper, Zinc, Tin and Sulfur, and Selenide with 12.6% record efficiency (2013-IBM). A 3-D simulation analysis is presented here on the optical, electrical, and thermal characteristics of CZTSSe solar cell using COMSOL multiphysics 3-D simulation package. COMSOL is capable of calculating the optical–electrical–thermal models through electromagnetic wave, semiconductor, and heat transfer modules for a finely meshed structure. Using this capability, we have calculated the optical photogeneration rate of the a Mo/Mo(S,Se) $_2$ /CZTSSe/CdS/ZnO/ITO/air structure by inserting the refractive index and extinction coefficient of every layer in Wave optic module in COMSOL. We also calculated the total optical generation rate for two structures with and without Mo(S,Se) $_2$ layer at the junction of Mo and CZTSSe layers. The current–voltage curve, electric field profile, and the recombination rate of the cell has also been calculated by Semiconductor module coupled to wave optic module. The current–voltage characteristics show an improvement in $V_{\text{oc}}$ for the cell with Mo(S,Se) $_2$ layer (0.46 to 0.513 V) which was also suggested by IBM for a record cell efficiency. Finally, the thermal maps of the cell has been calculated by heat transfer module coupled to semiconductor module considering the Shockley–Read–Hall (SRH) recombination heat, Joule Heat, and conductive heat flux. The total heat flux magnitude of the cell was also mapped as a result out of these heat generation and cooling sources. The SRH heat is maximum within the depletion width at the CZTSSe/CdS interface, whereas the Joule heating is intensive at the Mo/Mo(S,Se) $_2$ /CZTSSe side. Interesting is to see that the heat is mainly conducted to environment from Mo side presented by the conductive heat map. The total heat flux is intensive at both top and bottom interfaces which means the heat is generated at both top and bottom sides of the cells and not only from the illuminated partItem Open Access Sustainability assessment for manufacturing operations(MDPI, 2020-05-29) Saxena, Prateek; Stavropoulos, Panagiotis; Kechagias, John; Salonitis, KonstantinosSustainability is becoming more and more important as a decision attribute in the manufacturing environment. However, quantitative metrics for all the aspects of the triple bottom line are difficult to assess. Within the present paper, the sustainability metrics are considered in tandem with other traditional manufacturing metrics such as time, flexibility, and quality and a novel framework is presented that integrates information and requirements from Computer-Aided Technologies (CAx) systems. A novel tool is outlined for considering a number of key performance indicators related to the triple bottom line when deciding the most appropriate process route. The implemented system allows the assessment of alternative process plans considering the market demands and available resources.Item Open Access Sustainability assessment of rapid sand mould-making using multi-criteria decision making mapping(Springer, 2020-09-11) Pagone, Emanuele; Saxena, Prateek; Papanikolaou, Michail; Salonitis, Konstantinos; Jolly, Mark R.Capabilities of Additive Manufacturing (AM) for rapid tooling are well known in recent times. Rapid sand moulds are advantageous over traditional sand moulds in terms of cost, manufacturing time, flexibility, etc. This paper identifies metrics related to mould manufacturing and categorises them into four categories (cost, time, quality and environmental sustainability). A methodology based on the deterministic Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria decision making algorithm is used to map at high-resolution the influence of such categories on to the decision-making space when comparing AM with conventional sand mould making. Results show that AM is almost always clearly advantageous overall (excluding some very limited corner cases) for the examined caseItem Open Access Sustainability metrics for rapid manufacturing of the sand casting moulds: A multi-criteria decision-making algorithm-based approach(Elsevier, 2021-05-18) Saxena, Prateek; Pagone, Emanuele; Salonitis, Konstantinos; Jolly, Mark R.Additive Manufacturing has significantly developed over the years and is widely used in most industrial applications. Rapid Tooling refers to manufacturing the tools (moulds and dies) using Additive Manufacturing techniques. An essential application of Rapid Tooling is the 3D printing of sand moulds for castings. Metal casting is an energy-intensive process; and a lot of research has gone into the sustainability assessment of traditional sand castings. In this work, a robust decision-making approach is developed and implemented for sand mould manufacturing. Sustainability metrics for the mould production are formulated, and the conventional sand moulds are compared against the 3D printed sand moulds. A Multi-Criteria decision-making algorithm is implemented, and the effect of the batch size in the mould manufacturing is also studied. The discussed approach can help decision-makers choose the best mould manufacturing technique for the intended number of moulds to be manufactured.Item Open Access Tribo-mechanical characterization of carbon fiber-reinforced cyanate ester resins modified with fillers identification of communication signals using learning approaches for cognitive radio applications(MDPI, 2020-07-31) Bajpai, Ankur; Saxena, Prateek; Kunze, KlausHigh-performance polymer composites are being increasingly favored for structural applications. For this purpose, efforts are being focused on exploring the potential of high-performance thermoplastics and thermosets. Cyanate ester (CE) resin is a special thermoset that can be used at up to 400 °C without any considerable degradation; however, its tribological properties are not at the adequate level. Hence, it is needed to use this polymer in composite form with the fibrous/particulate reinforcement to impart better tribological properties and mechanical strength via a strong fiber–matrix interface. Carbon fiber/fabrics are at the forefront as reinforcement for specialty polymers. The tribological and tensile properties of cyanate ester (CE) composites-filled graphite, polytetrafluoroethylene (PTFE), and MoS2 micron-sized fillers reinforced with carbon fibers (CF) are investigated experimentally in a block-on-ring setup at 100 N, for 10 h, and with a sliding distance of approximately 10,000 m, against a hardened polished 100Cr6 steel shaft and diamond-like-coated (DLC) 100Cr6 steel shaft. The tribological properties of the composites including the coefficient of friction and specific wear rate are enhanced especially with the incorporation of graphite fillers. The friction coefficient and wear rate of the graphite-based composite was decreased significantly at 5 wt.% of graphite concentration. Further, at the same concentration, the graphite-based composite showed superior tensile properties as compared to the reference system owing to better dispersion and adhesion between the fibers and matrix. Tensile tests are performed to characterize the fiber–matrix interfacial adhesion and other strength properties