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Aquaponics, one of the vertical farming methods, is a combination of aquaculture and hydroponics. To enhance the production capabilities of the aquaponics system and maximize crop yield on a commercial level, integration of Industry 4.0 technologies is needed. Industry 4.0 is a strategic initiative characterized by the fusion of emerging technologies such as big data and analytics, internet of things, robotics, cloud computing, and artificial intelligence. The realization of aquaponics 4.0, however, requires an efficient flow and integration of data due to the presence of complex biological processes. A key challenge in this essence is to deal with the semantic heterogeneity of multiple data resources. An ontology that is regarded as one of the normative tools solves the semantic interoperation problem by describing, extracting, and sharing the domains’ knowledge. In the field of agriculture, several ontologies are developed for the soil-based farming methods, but so far, no attempt has been made to represent the knowledge of the aquaponics 4.0 system in the form of an ontology model. Therefore, this study proposes a unified ontology model, AquaONT, to represent and store the essential knowledge of an aquaponics 4.0 system. This ontology provides a mechanism for sharing and reusing the aquaponics 4.0 system’s knowledge to solve the semantic interoperation problem. AquaONT is built from indoor vertical farming terminologies and is validated and implemented by considering experimental test cases related to environmental parameters, design configuration, and product quality. The proposed ontology model will help vertical farm practitioners with more transparent decision-making regarding crop production, product quality, and facility layout of the aquaponics farm. For future work, a decision support system will be developed using this ontology model and artificial intelligence techniques for autonomous data-driven decisions.

Hyperbola fitting is a mainstream interpretation technique used in ground-penetrating radar (GPR) due to its simplicity and relatively low computational requirements. Conventional hyperbola fitting is based on the assumption that the investigated medium is a homogeneous half-space, and that the target is an ideal reflector with zero radius. However, the zero-radius assumption can be easily removed by formulating the problem in a more generalized way that considers targets with arbitrary size. Such approaches were recently investigated in the literature, suggesting that hyperbola fitting can be used not only for estimating the velocity of the medium, but also for estimating the radius of subsurface cylinders, a very challenging problem with no conclusive solution to this day. In this letter, through a series of synthetic and laboratory experiments, we demonstrate that for practical GPR survey, hyperbola fitting is not suitable for simultaneously estimating both the velocity of the medium and the size of the target, due to its inherent nonuniqueness, making the results unreliable and sensitive to noise.

Industry 4.0 promises to increase productivity and flexibility for the manufacturing industry, which translates into greater customer value and lower costs. Lean manufacturing has long championed principles and tools with a focus on value adding activities, elimination of waste and continuous improvement. Even the most successful lean manufacturing firms, in terms of efficiency and quality achieved through waste reduction, will acknowledge there is a lot of opportunity for improvement. This review evaluates how lean principles can support Industry 4.0 in pursuit of greater customer value and manufacturing excellence. Leveraging the opportunities that exist within Industry 4.0 umbrella of technologies can help to further reduce the nine wastes of lean. While large corporations have access to extensive capital markets and can capture economies of scale offered by leading edge technologies of Industry 4.0, small and medium sized enterprises (SMEs) with greater capital restraints face the challenge of justifying Industry 4.0 technologies and cannot risk being at the bleeding edge of technology. Using a case study of a small electronics manufacturing firm, the opportunities, challenges, and the implementation strategy for technology are examined. This paper finds that SMEs pursuit of process efficiencies and waste reduction can be best achieved through a focus on foundational digitalization & data management then taking a stepwise approach towards the cyber-physical systems of Industry 4.0.

Recent advances in manufacturing research have set the stage for the industrial integration of zero-defect manufacturing strategies, aiming towards a more sustainable production paradigm. A systematically deployment guideline to implement zero-defect manufacturing is needed to transform the future cyber-physical factory floor. This paper describes a novel framework based on a well-known cyber-physical architecture that provides advanced information analytics, robust information flows, and data acquisition systems that support defect detection and prediction introduces repair technologies and sets up procedures for preventive maintenance. Through continuous inspection of product and equipment status during the manufacturing process, raw quality and tool health data from different sources is used to obtain key performance indicators. Statistical tools such as cross-correlation are then applied to quantify underlying relationships between product quality specifications and equipment health. The resulting correlations are then used to reduce non-conformance of products manufactured by implementation of preventive maintenance. A unified implementation for zero-defect manufacturing cyber-physical processes eases their integration in future Industry 4.0 facilities and validated in the context of offsite construction manufacturing of steel frame assemblies.

Nanomaterials such as graphene have been added to various matrices to enhance mechanical, thermal and electrical properties for various applications requiring intricate designs at the micro-scale. At this scale, mechanical micro-machining is utilised as post-processing to achieve high surface quality and dimensional accuracy while still maintaining high productivity. Therefore, in this study, the machinability of polymer nanocomposites in micro-scale (micro-machinability) is investigated. Graphene (0.3 wt%)-reinforced epoxy nanocomposites were fabricated using traditional solution mixing and moulding. The samples were then subjected to micro-milling at various cutting speeds using three different micro-tools, including uncoated, diamond and diamond-like carbon (DLC) tools. Mechanical and thermal properties of nanocomposite were also used to support the discussions. The result indicates that the DLC-coated tool shows better performance than the other tools for less tool wear, improved surface quality and less cutting forces.

Digital twin (DT) is a virtual mirror (representation) of a physical world or a system along its lifecycle. As for a complex discrete manufacturing system (DMS), it is a digital model for emulating or reproducing the functions or actions of a real manufacturing system by giving the system simulation information or directly driven by a real system with proper connections between the DT model and the real-world system. It is a key building block for smart factory and manufacturing under the Industry 4.0 paradigm. The key research question is how to effectively create a DT model during the design stage of a complex manufacturing system and to make it usable throughout the system’s lifecycle such as the production stage. Given that there are some existing discussions on DT framework development, this paper focuses on the modeling methods for rapidly creating a virtual model and the connection implementation mechanism between a physical world production system at a workshop level and its mirrored virtual model. To reach above goals, in this paper, the discrete event system (DES) modeling theory is applied to the three-dimension DT model. First, for formally representing a manufacturing system and creating its virtual model, seven basic elements: controller, executor, processor, buffer, flowing entity, virtual service node and logistics path of a DMS have been identified and the concept of the logistics path network and the service cell is introduced to uniformly describe a manufacturing system. Second, for implementing interconnection and interaction, a new interconnection and data interaction mechanism between the physical system and its virtual model for through-life applications has been designed. With them, each service cell consists of seven elements and encapsulates input/output information and control logic. All the discrete cells are constructed and mapped onto different production-process-oriented digital manufacturing modules by integrating logical, geometric and data models. As a result, the virtual-physical connection is realized to form a DT model. The proposed virtual modeling method and the associated connection mechanism have been applied to a real-world workshop DT to demonstrate its practicality and usefulness.

Currently, damage identification and localization in remanufacturing is a manual visual task. It is time-consuming, labour-intensive. and can result in an imprecise repair. To mitigate this, an automatic vision-based damage localization method is proposed in this paper that integrates a camera in a robotic laser cladding repair cell. Two case studies analyzing different configurations of Faster Region-based Convolutional neural networks (R-CNN) are performed. This research aims to select the most suitable configuration to localize the wear on damaged fixed bends. Images were collected for testing and training the R-CNN and the results of this study indicated a decreasing trend in training and validation losses and a mean average precision (mAP) of 88.7%.

Composite industry increasingly uses natural fibres because of their environment-friendly advantages. These natural fibres may swell during the mould filling process when they absorb resin, and this swelling reduces the porosity and permeability of the preform. Hence, computational modelling of the flow in swelling porous media would be useful to model the different mould filling processes with the swelling effect. This paper demonstrates the possibility of using computational fluid dynamics to study the effect of swelling on liquid composite moulding mould filling in isotropic and orthotropic porous media. An empirical relation for local permeability changes is used to model the flow of resin under constant volume flow rate and constant injection pressure conditions. The flow front locations and inlet pressure predicted by the computational fluid dynamics simulations are in good agreement with the experimental data for 1D rectilinear flow case. Further, to capture the flow patterns, two different arrangements employing point injection are considered. It was observed that the volume fraction of resin in swelling porous medium is 6% less than rigid porous medium at any given time. It was also observed that the location of the inlet and outlet has a considerable effect on the flow front advancement.

In this study, turbulent flow characteristics of CuO-water nanofluid through heat exchanger pipe enhanced with louvered strips are numerically investigated. Nanoparticles volume fraction (ϕ) varied from 0 to 2%. The louvered strips are mounted in single and double geometries. The slant angle (θ) and the Reynolds number (Re) are within 15° − 25° and between 5000 and 14,000, respectively. (RNG) k − ϵ model is employed based on the finite volume technique. The results illustrated that strong flow disturbance between the wall and the louvered strip is the main reason for turbulent kinetic energy increment. Besides, the nanoparticles improve the thermophysical properties of the working fluid, which results in better heat transfer. The Nu number increases 15.6% by using nanofluid instead of water at Re = 14000. The highest thermal enhancement parameter of 1.99 is obtained at Re = 14000 by using double perforated louvered strip with θ = 25°. The recirculating flow inside the holes can significantly improve the thermal performance.

Superhydrophobic coatings and slippery liquid-infused porous surfaces (SLIPS) have shown their potentials in self-cleaning, anti-icing, anti-erosion, and antibiofouling applications. Various studies have been done on controlling the droplet impact on such surfaces using passive methods such as modifying the lubricant layer thickness in SLIPS. Despite their effectiveness, passive methods lack on-demand control over the impact dynamics of droplets. This paper introduces a new method to actively control the droplet impact onto superhydrophobic and SLIPS surfaces using surface acoustic waves (SAWs). In this study, we designed and fabricated SLIPS on ZnO/aluminum thin-film SAW devices and investigated different scenarios of droplet impact on the surfaces compared to those on similar superhydrophobic-coated surfaces. Our results showed that SAWs have insignificant influences on the impact dynamics of a porous and superhydrophobic surface without an infused oil layer. However, after infusion with oil, SAW energy could be effectively transferred to the droplet, thus modifying its impact dynamics onto the superhydrophobic surface. Results showed that by applying SAWs, the spreading and retraction behaviors of the droplets are altered on the SLIPS surface, leading to a change in a droplet impact regime from deposition to complete rebound with altered rebounding angles. Moreover, the contact time was reduced up to 30% when applying SAWs on surfaces with an optimum oil lubricant thickness of ∼8 μm. Our work offers an effective way of applying SAW technology along with SLIPS to effectively reduce the contact time and alter the droplet rebound angles.

Composite materials due to their high strength to density characteristics are widely used in aerospace, automotive, marine applications etc. Recent developments in Additive Manufacturing processes and materials have enabled the manufacture of end-use functional components. This paper investigates the fatigue behaviour of composite parts processed Additive Manufacturing (AM) process Continuous Fibre Fabrication reinforcement (CFF) method. There are existing data for static material properties however they are only a few published papers on the fatigue performance of parts processed by CFF additive manufacturing. This study investigates by physical and digital simulation, the fatigue life of 0, 2, 4, 6, 8 layer carbon fibre reinforced Nylon ASTME606M test samples. This research has determined design for fatigue guidelines for additively manufactured composite materials, for both for the low and high cycle applications.

A simple optic-fiber Fabry-Perot (FP) sensing technique was proposed and experimentally investigated by using polymer material to connect the ends of two singlemode fibers. Four different polymer materials (benzocyclobutene (BCB), UV88 (Relentless, China), Loctite3525 (HenKel, Germany), and NOA68 (Norland, USA)) filling the FP cavity were used to comparatively study the sensing performance of temperature, strain and refractive index. The result shows that the FP sensor with BCB has excellent repeatability with good linear response to temperature in a wide range from room temperature to 250 °C, which is much larger than that of other three materials (2)) and the best repeatability among the four polymer materials.

Adjustment on resonance frequency stability against the sintering temperature of Sr3V2O8 was realized by adjusting the Sr:V mole ratio. Effects of Sr:V ratio on sintering behavior and dielectric properties of Sr3V2O8 were studied. The sintering temperature was sucessfully reduced to 950°C from 1150°C. With increasing vanadium content, both relative permittivity and quality factor decreased, while the temperature coefficient of resonance frequency shifted from positive to negative values. Especially, a near‐zero τf of −1.1 ppm/°C along with a low permittivity (εr) of 9.8 and a quality factor Q × f of 24 120 GHz was successfully achieved in Sr3‐yV2O8‐y ceramic (y = 0.6, sintered at 950°C). The wide compositional and processing adjustment window, favorable dielectric performances, and good chemical compatibility with silver render Sr3‐yV2O8‐y ceramics potential candidates in multilayer electronic devices.

Capillary pressure is frequently measured to evaluate the shrinkage performance of concrete but has been limited to pressures

The high-fidelity computational fluid dynamics (CFD) simulations of a complete wind turbine model usually require significant computational resources. It will require much more resources if the fluid–structure interactions (FSIs) between the blade and the flow are considered, and it has been the major challenge in the industry. The aeromechanical analysis of a complete wind turbine model using a high-fidelity CFD method is discussed in this paper. The distinctiveness of this paper is the application of the nonlinear frequency domain solution method to analyze the forced response and flutter instability of the blade as well as to investigate the unsteady flow field across the wind turbine rotor and the tower. This method also enables the aeromechanical simulations of wind turbines for various interblade phase angles in a combination with a phase shift solution method. Extensive validations of the nonlinear frequency domain solution method against the conventional time domain solution method reveal that the proposed frequency domain solution method can reduce the computational cost by one to two orders of magnitude.

Solar and wind power systems have been prime solutions to the challenges centered on reliable power supply, sustainability, and energy costs for several years. However, there are still various challenges in these renewable industries, especially regarding limited peak periods. Solar–wind hybrid technology introduced to mitigate these setbacks has significant drawbacks and suffers from low adoption rates in many geographies. Hence, it is essential to investigate the challenges faced with these technologies and analyze the viable solutions proposed. This work examined solar–wind hybrid plants’ economic and technical opportunities and challenges. In the present work, the pressing challenges solar–wind hybrids face were detailed through extensive case studies, the case study of enabling policies in India, and overproduction in Germany. Presently, the principal challenges of solar–wind hybrids are overproduction, enabling policies, and electricity storage. This review highlights specific, viable, proposed solutions to these problems. As already recorded in the literature, it was discovered that academic research in this space focuses majorly on the techno-economic and seemingly theoretical aspects of these hybrid systems. In contrast, reports and publications from original equipment manufacturers (OEMs) and engineering, procurement, and construction engineers (EPCs) are more rounded, featuring real-life application and implementation.

In this study, computational simulations have been performed to investigate the turbulent characteristics and energy consumption through heat exchanger tubes equipped by new perforated V-shaped rectangular winglet (PVRW) turbulators. The effects of the holes intensity on the velocity and temperature contours are additionally investigated. The Reynolds number, hole diameter ratio, and the number of holes selected are in the range of 5000 ≤ Re ≤ 18,000, 0 ≤ DR ≤ 0.40, and 0 ≤ N ≤ 14, respectively. Renormalization group (RNG) k–ε turbulent model which is a finite volume solver is utilized for the computational fluid dynamics (CFD) simulation. It was noticed that the proposed perforated turbulators could considerably intensify the thermal performance compared to typical VRW inserts. It is found that the recirculating flow generated by the PVRW augments the fluid mixing and transfers the heat from the pipe walls to the core of the tube. The simulations illustrate that the amount of heat transfer enhances 25.2% reducing the DR from 0.4 to 0.13 at Re = 18,000 and N = 14. Also, using PVRW turbulators with N = 7 and DR = 0.26 augments the average Nusselt number around 354.3% compared to the circular pipe without inserts. The highest thermal efficiency parameter of η = 2.25 could be obtained at Re = 5000 for the heat exchangers fitted by vortex generators with N = 14 and DR = 0.26.

Critical high-tech minerals (CHTMs) are raw materials that are essential for a future clean-energy transition and the manufacture of high-end products. Cellphones, one of the fastest growing electronic products, contain various CHTMs. Since 2019, India has surpassed the United States to become the second largest smartphone market in the world. An increasing and alarming number of excessive waste cellphones will be generated in India in the near future. In this study, the dynamic material flow analysis approach and the Weibull distribution are adopted to analyze the volumes of accumulated waste cellphones and the contained CHTMs based on the differentiation between smartphones and feature phones in India. Moreover, a market supply model is adopted to predict the future trends of CHTMs in waste cellphones. The results show a general upward tendency of waste cellphone volume in India, which indicates that various CHTMs contained in cellphone waste can be properly reused or recycled. Future implications based on the analysis results are provided for efficient cellphone management in India.

Micromachining of nanocomposites is deemed to be a complicated process due to the anisotropic, heterogeneous structure, and advanced mechanical properties of these materials associated with the size effects in micromachining. It leads to poorer machinability in terms of high cutting force, low surface quality, and high rate of tool wear. In part 1 of this two-part review paper, a comprehensive review on mechanical properties of various nanocomposites will be presented while the second part of the paper will focus on the micro-machinability of these nanocomposite materials.

Micromachining of nanocomposites is deemed to be a complicated process due to the anisotropic, heterogeneous structure and advanced mechanical properties of these materials associated with the size effects in micromachining. It leads to poorer machinability in terms of high cutting force, low surface quality, and high rate of tool wear. A comprehensive review on mechanical properties of nanocomposites aiming to pointout their effects on micro-machinability has been addressed in part 1. In part 2, the subsequent micro-machining processes are critically discussed based on relevant studies from both experimental and modeling approaches. The main findings and limitations of these micro-machining methods in processing nanocomposites have been highlighted together with future prospects.

Waste, Energy and Transport are three of the main sectors of the human society. The three sectors have substantially been studied in their individual right and there is a plethora of literature available on them individually and also collectively in varying combinations. For instance, Waste to Energy is a well-established field, and so is the energy usage by the transport sector. However, there is an extreme knowledge gap in connection to energy being generated by incinerating waste in order to propel the means of the transport be it in air/aviation, terrestrial/automobile and locomotives or water/marine vessels. The paper focuses on this knowledge gap, thereby, aiming to create theoretical models of this concept. Therefore, the core nature of this study is conceptual. Relevant secondary data is drawn from the existing literature in the form of numbers and graphs to quantitatively establish the state of each of the three sectors before being joined together into a new nexus called Waste to Energy for Transport and abbreviated as WET Nexus. An account of challenges as well as benefits is outlined regarding the possibility of replacing the consumption of fossil fuel by waste-to-energy i.e. a kind of ‘on-board’ waste incineration to propel maritime vessels and also supply energy to ‘on-board’ built environments. Thus, killing two birds (transport and waste) with one stone (energy). The paper also touches upon innovative insights and future research potentials in terms of how maritime transport being driven by energy-from-waste instead of fossil fuels, can improve environmental sustainability; help climate emergency agendas and; also contribute to the Climate Action, which is one of the seventeen SDGs (Sustainable Development Goals) introduced by the UN (United Nations).

Remanufacturing as well as quality improving innovations are important activities to improve sustainability. However, when coexisting in one company, their interaction is not clear. On the one hand, past research found a positive impact of remanufacturing on product quality. On the other hand, remanufacturing was shown to be negatively affected by an industry’s technology trajectory of quality improvements. Using a stylized model of endogenous product quality improvement and remanufacturing we find that the main driver of the contradicting results is the change in manufacturing costs caused by improving product quality. A strong increase in manufacturing costs due to product quality improvement may induce the firm to take up remanufacturing when introducing the new product. Conversely, a small impact of product quality improvement on manufacturing costs reverses this effect and may indeed lead the firm to cease remanufacturing when introducing the new product. We find that the latter outcome is never beneficial from an environmental point of view, while the former always is. With endogenous product quality improving innovation we then characterize conditions where a remanufacturing manufacturer would take a different product quality improvement decision than a non-remanufacturing manufacturer. We observe that remanufacturing stifles (stimulates) product quality improvement when manufacturing cost of quality improved products are low (high). Neither of the two results are exclusively beneficial or detrimental from an environmental perspective and we characterize the conditions under which product quality improvement is preferable.

With the development of metal matrix composites (MMCs), the mechanical properties of MMCs with a small volume fraction of nano-sized particles were found to be even superior to that with a larger content of micron-sized particles. However, the improved mechanical properties of MMCs bring tremendous challenges such as premature tool failure in Ti machining process. This study exhibits an investigation on tool wear in micro milling of magnesium-based MMCs reinforced with 1.98 Vol.% of nano-sized titanium particles using 0.5-mm diameter two-flute tungsten carbide micro endmills. The tool wear was characterised both quantitatively and qualitatively by observing tool wear patterns and analysing the effect of cutting parameters on flank wear, reduction in tool diameter, cutting forces, surface roughness, and burr formation. A finite element model was established to understand matrix deformation and interaction between tool-particle and further explain the tool wear phenomena observed. Additionally, cutting performance using AlTiN coated and uncoated was also investigated. The results indicated that the main wear mechanisms were identified as flank wear and edge chipping due to abrasive wear and chip adhesion in uncoated micro endmills. These wear mechanisms were confirmed by chip formation process produced by finite element modelling (FEM). It was also observed that the largest tool wear occurred at the smallest feed per tooth (0.75 μm/tooth) and smallest wear occurred at the largest feed per tooth (3 μm/tooth). Also, the effect of BUE on tool wear and surface generation was studied.

This paper investigates dynamic properties of 3D rainbow lightweight hollow sphere foams both numerically and experimentally. Two rainbow hollow sphere foams are designed with linearly varying sphere shell thicknesses and binder diameters for the purpose of achieving broadband vibration attenuation at low frequencies. The hollow sphere foams are modeled by the finite element method. The band structures of two rainbow hollow sphere foams are compared with that of the uniform foam. The results show that the foam with gradient binders exhibits a bandgap more than two times broader than that of the uniform foam at lower frequencies, and the gradient binders also lead to locally concentrated vibration modes at the bandgap edges, which are different from the global vibration modes of the uniform foam. On the other hand, the foam with gradient shell thickness could not generate complete bandgaps due to the introduced additional modes by the varied shell thickness. The bandgap extension could, hence, be realized with properly designed structural gradients of foams. The rainbow and uniform hollow sphere foam samples are manufactured subsequently by the additive manufacturing method and tested with a frequency response function measurement system. The experimental results verify the numerical calculation as well as prove further the effects of gradient designs on bandgap extension. The proposed rainbow hollow sphere foams could be instructive for future researchers to design lightweight acoustic/dynamic structures for broadband low frequency noise and vibration control.

Growing concrete consumption has gradually depleted conventional resources. This research incorporates silicomanganese (SiMn) slag, marine sand and seawater as alternative concreting materials. The use of SiMn slag to replace limestone as coarse aggregate enhances sustainability, though reducing strength and durability of concrete. This research aims to enhance the SiMn slag concrete by incorporating silica fume (SF) and fly ash (FA). The interaction of SF and FA on strength, durability and workability of concrete is investigated by statistically evaluating the experimental result. In this regard, the polynomial function prediction model is developed using the Response Surface Method (RSM) for the optimization of SF and FA contents. Analysis of variance (ANOVA) using p-value at significance level of 0.05 showed that the models were statistically significant and had marginal residual errors. All models had high fitness with R 2 value ranging from 0.853 to 0.999. Adequate precision of models was above 4, indicating that the models had a low prediction error and were fit for optimization. Optimization indicated that a combination of 11.5% SF and 16.3% FA produced concrete that met the optimization criteria. Experimental validation showed that the highest prediction error was 3.4% for compressive strength , 3.2% for tensile strength , 4.9% for sorptivity and 18% for chloride permeability. The optimized concrete exhibited compact microstructure with good bonding between aggregate and cement paste . By using the established linear equation with SiMn slag concrete, the models also predicted the compressive strength of limestone concrete containing SF and FA with an error of between 0.9% and 5.4%.

Traditional job shop scheduling is concentrated on centralized scheduling or semi-distributed scheduling. Under the Industry 4.0, the scheduling should deal with a smart and distributed manufacturing system supported by novel and emerging manufacturing technologies such as mass customization, Cyber-Physics Systems, Digital Twin, and SMAC (Social, Mobile, Analytics, Cloud). The scheduling research needs to shift its focus to smart distributed scheduling modeling and optimization. In order to transferring traditional scheduling into smart distributed scheduling (SDS), we aim to answer two questions: (1) what traditional scheduling methods and techniques can be combined and reused in SDS and (2) what are new methods and techniques required for SDS. In this paper, we first review existing researches from over 120 papers and answer the first question and then we explore a future research direction in SDS and discuss the new techniques for developing future new JSP scheduling models and constructing a framework on solving the JSP problem under Industry 4.0.

The European Union implemented the End-of-Life Vehicle directive to deal with an estimated 6 million end-of-life vehicles each year. Existing literature describe the processes to deal with the waste at end-of-life of different products but there is a lack of information on the costing of these options. These costs remain a concern to automotive manufacturers. This paper therefore reports the end-of-life costs of vehicle components and also demonstrates how these costs can be predicted at the design stage. The proposed approach should help to decide whether the automotive parts are viable for remanufacture, refurbishment, recycling, or disposal from an economic perspective. Two different automotive parts have been selected as case studies to validate the approach. Assumptions were made during the development of the technique and based on the results, the proposed approach could potentially provide vehicle manufacturers a method of estimating the cost of end-of-life recovery processes of vehicle components.

The cost performance of a wide range of public sector infrastructure projects completed by a contractor are analysed and discussed. Change-orders after a contract to construct an asset was signed were, on average, found to contribute to a 23.75% increase in project costs. A positive association between an increase in change orders and the contractor’s margin were identified. Taxpayers pay for this additional cost, while those charged with constructing assets are rewarded with an increase in their margins. As the public sector embraces an era of digitisation, there is a need to improve the integration of design and construction activities and engender collaboration to ensure assets can be delivered cost effectively and future-proofed. The research paper provides empirical evidence for the public sector to re-consider the processes that are used to deliver their infrastructure assets so as to reduce the propensity for cost overruns and enable future-proofing to occur.

With the ever-increasing growth of electric vehicles (EV)s in the power industry, their significance as a flexible load has increased drastically. On the other hand, uncontrolled charging of these vehicles can cause serious problems in the grid, such as a peak in demand, a decrease in the life expectancy of transformers and as a result, an increase in charging costs of EVs for the EV owners. In this paper, a framework for day-ahead optimal charging of EVs is proposed which through optimization of active and reactive power exchange at each time interval, could prevent the problems mentioned above and at the same time increase the benefit of EV owners and network operators simultaneously. Furthermore, taking into account the effective factors on electrical energy consumption of EVs and the driving pattern of their owners, a route mapping algorithm is developed based on the proposed framework, so as to provide the EV owners with better services. The simulations are carried out using a hybrid interior-point optimization approach, based on traffic and geographic data collected from the city of Kowloon and a standard IEEE 33 bus system is used. The simulation results show that integrating optimal charging of EVs with a route mapping algorithm into the proposed framework can reduce the loss costs of the network during the hours of EVs’ presence in the framework and the selling price of electricity to EV owners by 24.93% and 33.6%, respectively in comparison with the uncontrolled mode. Also, the average life expectancy of power transformers is increased by 2.97% in the optimal charging mode compared to the uncontrolled mode.

This paper reports significant enhancement of corrosion resistance and electrical properties of waterborne epoxy coatings through additions of ceria modified graphene. Results showed that ceria particles were uniformly distributed and covalently bonded onto the surface of graphene. A dense interface layer was formed between the ceria modified graphene and epoxy matrix by aliphatic ether bonds. The composite coating with a modified graphene content of 0.5 wt% exhibited the best corrosion resistance with the highest impedance modulus (e.g., 103 Ω cm2 for the damaged coating) and the lowest corrosion rate (e.g., 0.002 mm/year). The excellent corrosion resistance of the composite coating is related to the barrier effect of graphene and the inhibition effect of ceria on metal corrosion. Moreover, the coating showed a low percolation threshold of 0.231 vol% and its electrical conductivity reached 10−5 S/m when the content of modified graphene was 0.5 wt%.

The foundry industry provides near net shape metal casting for a wide range of industries, producing components in ferrous and non-ferrous metal castings in a range of sizes from miniature items as small as zips to large castings such as ships' propellers.\ud \ud The sand casting process has changed little over centuries, except for incremental improvement in materials and mechanisation of the process, the fundamental process being that of sand compacted around a pre-manufactured mould pattern which is then removed to cast the metal. For mass production stage this is both efficient and economical, however during development and prototyping production stages the requirement for mould production tooling, the design constrained production method means this stage is often a major bottleneck in new product development.\ud \ud Additive manufacturing has been used to manufacture sand moulds for metal sand casting using laser sintering and sand bonding process without the need for tooling. This research focuses on optimisation of the build parameters for additive manufactured sand print bonded mould tools specifically for automotive aluminium castings.\ud \ud The approach taken in this research is to evaluate characteristics of casting produced and relates to the permeability, dimensional accuracy, tensile and compressive crush strength, density, impact strength and high temperature resistance of the mould tool produced. These properties are required to compare the 3D Sand Printing (3DSP) process to traditional Furan based casting sand mixtures. The automotive turbo charger casing was used to validate the build parameters optimisation process.\ud \ud This research would be of interest to designers and manufacturing engineers wishing to take advantage of the implications of having new design freedom, tool-less manufacturing with short lead times in a wide range of materials using fundamentally tried and tested foundry industry casting techniques. This research has demonstrated 3DSP process has the capability to manufacture sand patterns to permeability, accuracy, tensile and compressive strength comparable to traditional sand casting process.

This work aims to employ fused deposition modelling 3D printing to fabricate immediate release pharmaceutical tablets with several model drugs. It investigates the addition of non-melting filler to methacrylic matrix to facilitate FDM 3D printing and explore the impact of (i) the nature of filler, (ii) compatibility with the gears of the 3D printer and iii) polymer: filler ratio on the 3D printing process. Amongst the investigated fillers in this work, directly compressible lactose, spray-dried lactose and microcrystalline cellulose showed a level of degradation at 135°C whilst talc and TCP allowed consistent flow of the filament and a successful 3D printing of the tablet. A specially developed universal filament based on pharmaceutically approved methacrylic polymer (Eudragit EPO) and thermally stable filler, TCP (tribasic calcium phosphate) was optimised. Four model drugs with different physicochemical properties were included into ready-to-use mechanically stable tablets with immediate release properties. Following the two thermal processes (hot melt extrusion (HME) and fused deposition modelling (FDM) 3D printing), drug contents were 94.22%, 88.53%, 96.51% and 93.04% for 5-ASA, captopril, theophylline and prednisolone respectively. XRPD indicated that a fraction of 5-ASA, theophylline and prednisolone remained crystalline whilst captopril was in amorphous form. By combining the advantages of thermally stable pharmaceutically approved polymers and fillers, this unique approach provides a low cost production method for on demand manufacturing of individualised dosage forms.

This paper reports the development of a quantitative analysis system for selecting a greener and economically sustainable wind farm at the early design stage. A single wind turbine produces a limited amount of carbon emissions throughout its lifecycle. By taking a broader view, such as wind farms, collectively such an application would have a greater impact upon the environment and cost. Recent research on wind farms tends to focus on wind flow modelling to enable accurate prediction of power generation. Therefore, this paper presents a quantitative approach to predict a wind farm's lifetime (i) carbon emissions and intensity; (ii) potential energy production; (iii) return on investment and (iv) payback time from an early design perspective. The overall contribution of this work is to develop a quantitative approach to enable the selection of ‘greener’ designs for reducing the environmental impacts of a wind farm with hub heights between 44 m and 135 m while still considering its economic feasibility assessment. This newly developed system could potentially be used by top-management and engineers of wind turbine manufacturers and wind energy service providers for cleaner energy provision.

The UK is currently in the grip of a housing crisis, a recent report from the House of Lords stated that the shortage of affordable housing in Britain could jeopardise our standards of living for future generations. This paper aims to attempts to influence the problem of housing shortage by evaluating the potential of implementing fast building additive manufacturing (BAM) as a construction process. To validate the feasibility of BAM as a building process a variety of compressive and slump tests were conducted to assess the capabilities of concrete paste as a layer-by-layer build material. A structure was fabricated to represent a fused filament fabrication (FFF)-based BAM process; the tests determined that nozzle design limitation, the flowability of concrete and resistance to slump are key material characteristics in constructing house structural elements. Furthermore, the use of recyclable natural and steel wool fibres did not contribute to mixtures compressive strength but did significantly increase its flexural strength.

Organic compounds, often used in cement systems as admixtures, may affect the crystallisation and carbonation kinetics of Ca(OH)2, an important phase of hydrated cement. Here, we investigated changes in Ca(OH)2 morphology in the presence of 3 organic compounds, commonly encountered in cement and lime-based materials: sucrose, pectin and calcium lignosulfonate. The additives were introduced either before or after lime slaking to determine the influence of temperature. Ca(OH)2 crystals and supernatant solutions were characterised at time of slaking and after 6 months of ageing using scanning electron microscopy, X-ray diffraction and optical emission spectroscopy. Our results indicate that the morphology of Ca(OH)2 crystals is modified by the characteristics of the organic molecules which promote formation of Ca(OH)2 with habits that can result in faster carbonation, an effect that is detrimental to cement used in reinforced concrete. These effects are enhanced when the additives are introduced before slaking, likely as a result of thermal degradation.

The adverse effects of hostile marine environment on concrete structure have inevitably resulted in huge economic loss and may contribute to catastrophic failure. Concrete is susceptible to weathering, particularly under wetting-drying action (WDA), although its current state of the art is well established. The diverse characteristics of WDA at different site locations have compromised the reliability of laboratory works. The objective of this study is to review the impact of WDA on concrete and to provide an overview of the research trend, aiming to identify the research gap. Concrete deterioration mechanisms in marine environment in respect of WDA are identified. The influential factors of WDA are analyzed. The physical and mechanical properties and corrosion resistance of concrete exposed to WDA are discussed. WDA aggravates concrete deterioration by hastening intrusion of inimical compounds such as chloride, sulphate and carbon dioxide. Chloride convection zone can be expanded by two to three times to cause a significant concrete cover loss. Physical damage of concrete starts with efflorescence staining, followed by mortar delamination, aggregate detachment and concrete spalling, leading to loss of mechanical properties. The use of mineral admixtures such as fly ash and silica fume improves concrete resistance against corrosion, but its refining effect may lead to over-accumulation of chloride, risking the long-term durability. Limited research works are identified on synergy between physical and chemical deteriorations, validation of simulated experiment, volume expansion, mass change and tensile strength of concrete.

Large scale Fused Filament Fabrication (FFF) is a growing area of interest within AM, with several unresolved problems: the volumetric cost of materials is high, the printing process is slow and low cooling rates result in unstable or sagging structures. This paper presents the concept of additive manufacturing via tube extrusion (AMTEx) as a means of overcoming these issues. Using hollow tubes in place of solid extrusions means material use is reduced and cooling properties are vastly improved, allowing spans in excess of 400 mm without sag. Conventional freeform extrusion relies on the use of six-axis robots to orientate the extruder nozzle tangentially to the toolpath. It was found that slight pressurisation of the inside of printed tubes allowed extrusion at more than 90° from the nozzle axis without tube collapse. Aside from reducing the possibility of robot-print collisions, this also allows the use of traditional 3D printing slicing software to generate printer toolpaths. It also opens the potential to use conventional three-axis machines, greatly increasing the applicability of printing with tubes. AMTEx tubes were found to be stronger under tension and bending compared to equivalent FFF parts and had significantly improved ductility.

Purpose:\ud The concrete industry faces challenges to create concrete mix designs that reduce negative environmental impacts but also maintain high performance. This has led to ‘greener’ cementitious materials being developed which can decrease the use of traditional Portland cement (PC). This study intended to carry out a ‘cradle-to-gate’ life cycle assessment (LCA) on concrete mix designs containing different cementitious blends.\ud \ud Methods:\ud The aim of this study was to obtain the overall environmental impact, with a particular focus on carbon dioxide (CO2) emissions of three concrete mix designs: CEM I (100 % PC content), CEM II/B-V (65 % PC content, 35 % Fly Ash (FA) content) and CEM III/B (30 % PC content, 70 % ground granulated blast furnace slag (GGBS) content). Evaluations of the three concrete mixes were performed using ‘SimaPro 8’ LCA software. A comparative cradle-to-gate LCA of these mixes has not currently been explored and could present a new insight into improving the environmental impact of concrete with the use of secondary materials. Recommendations from this work would help the industry make key decisions about concrete mix designs.\ud \ud Results and discussion:\ud Results show that Mix 2 (CEM II/B-V) and Mix 3 (CEM III/B) could potentially be taken forwards to improve their environmental impacts of concrete production. With respect to optimum mix design, it is strongly recommended that GGBS is selected as the addition of choice for reducing CO2 emissions. FA does still considerably improve sustainability when compared to PC, but this work proved that inclusion of GGBS environmentally optimises the mix design even further. Advantages of using GGBS include lower CO2 emissions, a substantial reduction of environmental impacts and an increased scope for sustainability due to the higher PC replacement levels that are permitted for GGBS. Due to mix designs enabling a higher contribution of GGBS additions, it would also indicate an increased positive effect regarding waste scenarios.\ud \ud Conclusions and recommendations:\ud The main contribution of this work demonstrated that concrete can be produced without loss of performance whilst significantly reducing the negative environmental impacts incurred in its production. The results obtained from this work would help to define the available options for optimising concrete mix design. The only material variations in each mix were the different cementitious blends. So, by determining the best option, a platform to make recommendations can be established based upon cementitious materials.

For a paper manufacturer to remain competitive and sustainable, they must be able to manufacture at a low production cost with minimum resource consumption. One such approach to reduce manufacturing costs and take environmental issues into consideration could be the adoption of recycling and repurposing of waste paper. However, recent recycling research to address both environmental and economic challenges is predominately focused on the mechanical or electrical and electronics sectors. As the paper industry and consumers produce a large amount of waste paper, this lack of research highlights an important knowledge gap in the field of study. This article reviews the extent to which waste paper can be reused through recycling and repurposing. As a result, a cost modelling approach has been developed to predict cost fluctuations under different manufacturing constraints. The overall contributions of this research are: (i) identification of testing scenarios and parameters in waste paper; (ii) methods of recycling and repurposing cost modelling. A case study has been used to validate the method and based on the proposed approach, senior management of paper manufacturers could potentially achieve the best result to prevent unexpected costs and therefore maximise waste paper reuse.

Two computational methodologies – computational fluid dynamics (CFD) and the numerical modelling using linear potential theory based boundary element method (BEM) are compared against experimental measurements of the motion response of a pitching wave energy converter. CFD is considered as relatively rigorous approach offering non-linear incorporation of viscous and vortex phenomenon and capturing of the flow turbulence to some extent, whereas numerical approach of the BEM relies upon the linear frequency domain hydrodynamic calculations that can be further used for the time-domain analysis offering robust preliminary design analysis. This paper reports results from both approaches and concludes upon the comparison of numerical and experimental findings.

The need for high quality machining of composite materials is rising due to the increased utilisation of these materials across several applications. This paper presents experimental findings of orthogonal cutting of unidirectional glass fibre reinforced plastic (UD-GFRP) composites using HSS single-point cutting tools. Key process indicators including cutting forces, chip formation and surface integrity were evaluated. Full factorial design is employed with fibre orientation, depth of cut, cutting speed and rake angle as process control variables. Fibre orientation and depth of cut were found to be the most significant factors affecting the investigated responses. Lower cutting forces and better surface quality were obtained at 0o fibre orientation and lower depth of cut. Cutting at 45o fibre orientation generated extremely damaged surfaces with relatively high average surface roughness values and should be avoided in practical applications.

This paper describes the development of a quantitative analysis system as a platform for rapidly estimate energy, costs and carbon emission to facilitate the comparison of different wind turbine concept designs. This system aimed specifically at wind turbine manufacturing processes due to the fact that a large proportion of the environmental, costs and energy impacts would occur at this stage. The proposed method supports an initial assessment of multiple design concepts which allows the selection and development of a “greener” wind turbine. The developed system enables concept design of commercial wind turbine towers of hub heights between 44 and 135 m. The method supports an accurate estimation in regards to the dimension, energy consumed, maximum power output, costs and carbon emission in the early design phases of a wind turbine. As a result of the development, the proposed approach could potentially be used to minimise the carbon footprints of major engineering projects such as wind farms.

Power consumed in metal cutting is typically converted into heat near the cutting tool edge. Cutting fluids are then provided to a cutting zone in order to improve the tribological characteristics of machining processes and to dissipate the generated heat. The use of conventional cutting fluids however has lately been questioned due to the adverse impact on the environment and human health. Therefore, trends are directed to various alternatives such as vegetable oils (VOs). VOs offer a combination of good biodegradability and high lubricity, eco-friendly and compatibility with additives, low toxicity and volatility, high flash points and high viscosity indices. This paper details preliminary experimental results when turning Ti-6Al-4V. The impact of VO-based cutting fluids, cutting tool materials and working conditions were investigated. Two sets of experimental plans were designed comprising 25 and 27 tests with analysis of variance (ANOVA) employed to evaluate the effect of process variables on Ra and tool flank wear. In general, surface roughness Ra ranged between 0.56μm and 1.81μm and statistical analysis showed that the main contributing factor for Ra is feed rate having a high Percentage Contribution Ratio (PCR) of 94.4%. Noticeable increase in tool tip flank wear was recorded when higher cutting speeds were used.

This paper presents the use of treated palm oil fuel ash (POFA) as a pozzolanic material in modified cement paste to control degradation in ammonium nitrate environment. The POFA used in this study had a mean diameter of 8.7µm. The treated POFA was used to replace cement in different percentage of 0%, 10%, 20% and 30% with a constant water to cement ratio of 0.4. 50mm cement cubes was prepared for mechanical, durability and micro-structural test. Mechanical test consisted of the compression strength test and durability test consisted of the Volume of Permeable Voids Test (VPV). Meanwhile, micro-structural test consisted of the Thermo-gravimetric analysis (TGA). After 28 days of full water curing, the 50mm cubes samples were immersed in 20% ammonium nitrate solution until 90 days. Based on the test results, it was observed that, cement cubes replaced with 20% POFA had good resistance against ammonium nitrate solution. However, in order to improve the current study, a number of recommendations had been suggested.

This paper presents an experimental study on the development of masonry block with Palm Oil Fuel Ash (POFA) as a partial replacement to cement whilst maintaining satisfactory properties of masonry block. The dosages of POFA are limited to 0%, 20%, 40% and 60% by mass of the total cementitious material in the masonry block. The experiments on masonry block investigate the compressive strength and the breaking load for mechanical properties and water absorption and efflorescence for its durability. The compressive strength and the breaking load of the masonry blocks reduce with increasing percentage of POFA replacement. However, it satisfies the requirements of Class 1 and Class 2 load-bearing masonry block according to Malaysian Standard MS76:1972. In terms of durability of the masonry block, water absorption for all the masonry blocks satisfies the requirement of ASTM C55-11 and there is no any sign of efflorescence on all the masonry blocks. POFA based masonry block are also found to be cheaper than the cement sand masonry blocks. The experimental studies indicate that POFA based masonry block has a significant potential for application in the construction industry.

This article presents a data modelling and a semi-automatic data searching method to support cost estimation in the product development process, particularly for low-volume, high-complexity and long-life products typified by defence products and systems. This article covers a literature review in the area of cost estimation in product development, the data sets needed to perform cost estimation, the method of modelling the data and the techniques of supporting cost data searching. The proposed method will be used to support cost estimation of product development decisions for defence electronic products. To compare with the traditional approach, the method has demonstrated that by creating a centralized environment such as the ‘databases and using a data-driven’ approach. The system is made more efficient by reducing the number of processes in carrying out cost estimation, and thus, this provides more information to make an informed concept design decision during the product development process based on the system’s competence of instant cost estimation feedback.

This paper reports on the investigation of an excavator mounted dust suppression system for demolition and construction activities. Ever increasing pressure is placed on contractors to improve their environmental performance, especially dust emissions. Current methods of dust suppression have been investigated and each of the methods has also been critically analysed to determine their advantages and disadvantages. The investigation also examined the requirements of such a system and a concept system proposal was produced. A working prototype has been constructed for a mini excavator complete with a hydraulic breaker. The proposed system was rigorously tested in various configurations to determine its efficiency and effectiveness in comparison with current suppression techniques. The resulting benefits such as the reduction of water usage and cost are highlighted.

The structural and electrical properties of a low resistivity CuAlMo thin film resistor material were investigated. The thin films were grown on Al2O3 and glass substrates by direct current (dc) magnetron sputtering. The key electrical properties of sheet resistance, temperature coefficient of resistance (TCR) and resistance stability were investigated as a function of sputtering pressure and post-deposition heat treatment time and temperature. A low sputtering pressure range of 0.13 to 0.40 Pa produced CuAlMo films with sheet resistance in the range 0.1 to 0.2 Ω/□ and resistance stability of 0.45 to 0.65% with a TCR of − 90 ppm/°C which could be shifted to zero following annealing in air at 425 °C. Films grown at higher sputtering pressures of 0.53 to 0.80 Pa had increased sheet resistance in the range 0.4 to 0.6 Ω/□ and inferior stability of 0.8 to 1.7% with a more negative TCR of − 110 to − 180 ppm/°C which could not be shifted to zero following annealing. The stability of the films grown at 0.13 and 0.40 Pa could be further improved to < 0.25% with heat treatment, due to the formation of a protective aluminium oxide layer. A minimum dwell time of 3 h at 425 °C was required to stabilise the films and set the electrical properties.

Project Knowledge Management is regarded as a field of increasing importance for both researchers and organisations. This led Volvo Technology, the innovation business unit within a Swedish automotive multinational corporation, to explore through a qualitative case study how Project Knowledge Management could be improved to support knowledge sharing between projects within the organisation. The current situation of Project Knowledge Management is described through a developed theoretical framework and with input from thirteen semi-structured interviews conducted and analysed in an iterative fashion. The description shows that the contributor employs the codification strategy to share knowledge with other projects while the receiver adapts a personalisation strategy to retrieve knowledge from other projects. This description was analysed and compared with current research through brainstorming. Since there are current initiatives within the organisation to improve the codification strategy, this research focuses on improving the personalisation strategy. The recommendation was to promote Communities of Practice. Six semi-structured interviews were conducted to evaluate the relevance of the recommendations. The recommendation was found to be relevant for improving Project Knowledge Management within Volvo Technology. © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of IPMA

The article aims to identify the scientific challenges and point out future research directions on Cost Engineering. The research areas covered in this article include Design Cost; Manufacturing Cost; Operating Cost; Life Cycle Cost; Risk and Uncertainty management and Affordability Engineering. Collected information at the Academic Forum on Cost Engineering held at Cranfield University in 2008 and further literature review findings are presented. The forum set the scope of the Cost Engineering research, a brainstorming was held on the forum and literatures were further reviewed to understand the current and future practices in cost engineering. The main benefits of the article include coverage of the current research on cost engineering from different perspectives and the future research areas on Cost Engineering.