• Experimental and numerical study on soot formation in laminar diffusion flames of biodiesels and methyl esters

      Tian, Bo; Anxiong, Liu; Chong, Cheng Tung; Fan, Luming; Ni, Shiyao; Jo-Han, Ng; Stelio, Rigopoulos; Kai, Luo; Hochgreb, Simone; University of Derby; et al. (Elsevier, 2020-08-05)
      Biodiesel and blends with petroleum diesel are promising renewable alternative fuels for engines. In the present study, the soot concentration generated from four biodiesels, two pure methyl esters, and their blends with petroleum diesel are measured in a series of fully pre-vapourised co-flow diffusion flames. The experimental measurements are conducted using planar laser induced-incandescence (LII) and laser extinction optical methods. The results show that the maximum local soot volume fractions of neat biodiesels are 24.4% - 41.2% of pure diesel, whereas the mean soot volume fraction of neat biodiesel cases was measured as 11.3% - 21.3% of pure diesel. The addition of biodiesel to diesel not only reduces the number of inception particles, but also inhibits their surface growth. The discretised population balance modelling of a complete set of soot processes is employed to compute the 2D soot volume fraction and size distribution across the tested flames. The results show that the model also demonstrates a reduction of both soot volume fraction and primary particle size by adding biodiesel fuels. However, it is not possible to clearly determine which factors are responsible for the reduction from the comparison alone. Moreover, analysis of the discrepancies between numerical and experimental results for diesel and low-blending cases offers an insight for the refinement of soot formation modelling of combustion with large-molecule fuels.
    • Performance comparison of resin-infused thermoplastic and thermoset 3D fabric composites under impact loading

      Choudhry, Rizwan Saeed; Shah, S. Z. H.; Megat-Yusoff, P.S.M.; Karuppanan, S.; Ahmad, F.; Sajid, Z.; Gerard, P.; Sharp, K.; Universiti Teknologi PETRONAS, Malaysia; University of Derby (Elsevier, 2020-07-29)
      In this paper, the impact performance of a novel resin-infused acrylic thermoplastic matrix-based 3D glass fabric composite (3D-FRC) has been evaluated and compared with thermoset based 3D-FRC under single as well as recurring strike low velocity impact (LVI) events. The single impact tests revealed that the thermoplastic-based 3D-FRC exhibits up to 45% reduced damage area and can have up to 20% higher impact load-bearing capacity (peak force). The damage mode characterization showed that damage transition energy required for micro to macro damage transition is 27% higher, and back face damage extension is up to 3 times less for thermoplastic-based 3D-FRC. Meanwhile, the recurring strike impact test highlights that the thermoplastic-based 3D-FRC experiences a 50% less damaged area, better structural integrity, and survived more strikes. The comparison of single and repeated LVI tests have also allowed us to present a design criterion for estimating the safe number of repeated LVI events for a given impact energy. The superior impact resistance of thermoplastic-based 3D-FRC is attributed to their higher interlaminar fracture toughness, a tougher fiber-matrix interface, matrix ductility, and unique failure mechanism of yarn straining, which is not present in thermoset composites.
    • Numerical study of the coupling between the instantaneous blade loading/power of an axial wind turbine and upstream turbulence at high Reynolds numbers

      Ahmadi, Mohammad H.B.; Yang, Zhiyin; University of Derby (Elsevier BV, 2020-07-06)
      Little is known about how the range of scales in the approaching turbulent flow can interact dynamically with wind turbines and influence its ability to produce power. Here, a numerical study of a horizontal-axis wind turbine at different Reynolds numbers (corresponding to different tip speed ratios) has been conducted to investigate the instantaneous turbine response to upstream turbulence. A computational approach, combining large eddy simulation with actuator line modelling, is adopted. Comparison between Power Spectral Density (PSD) of the turbine thrust/power and PSD of the velocity at the rotor plane and one rotor diameter upstream of it confirms that there is a coupling between the instantaneous turbine thrust/power and the upstream turbulence (one diameter upstream of the turbine) for frequencies below a critical frequency. Furthermore, it has been shown for the first time, that PSD of the turbine thrust/power and the velocity PSD at the rotor plane are very similar, indicating that the instantaneous turbine thrust/power and the velocity at the rotor plane are coupled for all frequencies. This means that the PSD of velocity at the rotor plane or shortly behind it can provide interesting information for the instantaneous turbine loads that are very important for the turbine operational life.
    • Synthesis of single-walled carbon nanotubes in rich hydrogen/air flames

      Zhang, Cen; Tian, Bo; Chong, Cheng Tung; Ding, Boning; Fan, Luming; Chang, Xin; Simone, Hochgreb; University of Cambridge; University of Derby; Shanghai Jiao Tong University (Elsevier, 2020-06-27)
      We explore the production of single-walled carbon nanotubes (CNTs) in a stream surrounded by rich premixedlaminar H2/air flames using a feedstock containing ethanol and ferrocene. The as-produced nanomaterialswere characterised by Raman spectroscopy, transmission electron microscopy, scanning electron microscopyand X-ray diffraction. A formation window of equivalence ratios of 1.00–1.20 was identified, and single-walledCNT bundles with individual CNTs of an average diameter of 1 nm were observed. The formation of CNTswas accompanied by the production of highly crystalline Fe3O4nanoparticles of a size of 20–100 nm. Theinvestigation of the limiting factors for the CNT synthesis was carried out systematically, assisted by numericalmodelling. We conclude that the key factors affecting CNT synthesis are the surrounding flame temperatures and the concentration of carbon available for CNT nucleation.
    • Energy performance and life cycle cost assessments of a photovoltaic/thermal assisted heat pump system

      Cui, Yuanlong; Zhu, Jie; Zoras, Stamatis; Qiao, Yaning; Zhang, Xin; University of Derby; University of Nottingham; China University of Mining and Technology; Cranfield University (Elsevier, 2020-06-26)
      A photovoltaic/thermal module assisted heat pump system is investigated in this paper, which provides electrical and thermal energy for a domestic building. In-depth evaluation on the system energy production is conducted based on the finite difference method for a long-term operating period. The 25 years’ system life cycle cost is assessed via the Monte Carlo simulation under the Feed-in Tariff (FiT) and Renewable Heat Incentive schemes, the annual energy savings, income and payback period (PBP) are compared for the FiT and Smart Export Guarantee (SEG) schemes. The technical analysis results illustrate that the system is able to fulfil the building thermal and electrical energy demands from April to October and from May to August, respectively, and the extra electricity of 229.47 kWh is fed into the grid. The economic assessment results clarify that the system achieves a net present value (NPV) of £38,990 and has a PBP of 4.15 years. Meanwhile, the economic sensitive analyses reveal that the high discount rate reduces the system NPV whereas the high investment cost causes a long PBP to realize the positive NPV. Compared with the SEG scheme, the FiT is the most cost-effective method for renewable electricity generation and has the shortest PBP.
    • The impact of industry 4.0 on sustainability and the circular economy reporting requirements

      Takhar, Sukhraj; Liyanage, Kapila; University of Derby (Inderscience, 2020-06-18)
      The traditional linear economic system focuses on the mass production of products, using available resources, at the lowest possible cost. Sustainability recognises the impact of dwindling natural resources, as a result of mass production and directs us towards the use of more sustainable resources. The circular economy (CE) proposes the adoption of an open loop manufacturing system where products are designed using resources which enable products to be repaired, reused, repurposed and recycled. To analyse the impacts of sustainability and CE initiatives, accurate data needs to be collected. Industry 4.0 promotes interconnectivity, enabling real-time data collection, communication and data analytics. This paper contributes to existing literature by identifying a research gap on how sustainability and CE model data reporting needs may be met using Industry 4.0 technologies. Using a literature review and survey on real-world adoption, a set of reporting requirements for sustainability and CE models are identified. The conclusions provide an assessment of how Industry 4.0 may aid reporting needs.
    • A mean free path approach to the micro/nanochannel gas flows

      Xie, Jianfei; University of Derby (Springer Nature, 2020-05-07)
      We investigate the gas flows near to solid surfaces in terms of the local spatial variation in the molecular mean free path (MFP). Molecular dynamics (MD) is the appropriate scientific tool for obtaining molecularly-accurate dynamic information in micro and nano-scale gas flows, and has been used to evaluate the molecular mean free path of gases. In the calibration procedure, the viscosity of a gas in the homogeneous case can be recovered in our MD simulations and reach good agreement with the theoretical prediction and data from NIST. In surface-bounded gas flows, if the collisions between gas molecules and walls are counted, a spatially-varying mean free path is presented, and for the first time we have observed that the distribution of the free paths deviates from the exponential one and spikes appear in their distributions at larger Kn, i.e. in the transition flow regime. Based on elementary kinetic theory, the effective viscosity of the gas derived from the mean free path has been incorporated into the framework of the continuum-fluid dynamics equations, and micro-Couette flows are performed to demonstrate this potential application.
    • A review of in-situ grown nanocomposite coatings for titanium alloy implants

      Gunputh, Urvashi Fowdar; Le, Huirong; Pawlik, Marzena; University of Derby (MDPI AG, 2020-04-21)
      Composite coatings are commonly applied to medical metal implants in order to improve biocompatibility and/or bioactivity. In this context, two types of titanium-based composite coatings have been reviewed as biocompatible and anti-bacterial coatings. The different composites can be synthesised on the surface of titanium using various methods, which have their own advantages and disadvantages. Moving with the smart and nanotechnology, multifunctional nanocomposite coatings have been introduced on implants and scaffolds for tissue engineering with the aim of providing more than one properties when required. In this context, titanium dioxide (TiO2) nanotubes have been shown to enhance the properties of titanium-based implants as part of nanocomposite coatings.
    • Solder joint failures under thermo-mechanical loading conditions – a review

      Depiver, Joshua Adeniyi; Mallik, Sabuj; Harmanto, Dani; University of Derby (Taylor & Francis, 2020-04-18)
      Solder joints play a critical role in electronic devices by providing electrical, mechanical and thermal interconnections. These miniature joints are also the weakest links in an electronic device. Under severe thermal and mechanical loadings, solder joints could fail in ‘tensile fracture’ due to stress overloading, ‘fatigue failure’ because of the application of cyclical stress and ‘creep failure’ due to a permanent long-term load. This paper reviews the literature on solder joint failures under thermo-mechanical loading conditions, with a particular emphasis on fatigue and creep failures. Literature reviews mainly focused on commonly used lead-free Sn-Ag-Cu (SAC) solders. Based on the literature in experimental and simulation studies on solder joints, it was found that fatigue failures are widely induced by accelerated thermal cycling (ATC). During ATC, the mismatch in coefficients of thermal expansion (CTE) between different elements of electronics assembly contributes significantly to induce thermal stresses on solder joints. The fatigue life of solder joints is predicted based on phenomenological fatigue models that utilise materials properties as inputs. A comparative study of 14 different fatigue life prediction models is presented with their relative advantages, scope and limitations. Creep failures in solder joints, on the other hand, are commonly induced through isothermal ageing. A critical review of various creep models is presented. Many of these strain rate-based creep models are routed to a very well-known Anand Model of inelastic strain rate. Finally, the paper outlined the combined effect of creep and fatigue on solder joint failure.
    • Exposing the unconscious through the para-architectural photo-essay and prose

      D’Arcy-Reed, Louis; University of Derby (Taylor and Francis, 2020-04-02)
      Para-architecture as a method of design exploits the creative potential within interdisciplinary practices such as philosophy, sculpture, cartoons, as a supplement to conventional design methodologies. This photo essay expands upon such methods originally highlighted within Bernard Tschumi’s Manhattan Transcripts (1976), in a parallel to unconscious principles of psychoanalytic “site-writing”, as proposed by Jane Rendell. Responding to the Hepworth Wakefield, United Kingdom, as the architectural object, photography and intuitive prose are explored as para-architectural tools of interrogation. Through an original series of photographs and developed prose, a diagnosis and analysis takes place – harnessing the potential of utilizing para-architectural methods to explore the unconscious of cultural architectural interventions. The future potential in subscribing to para-architectural inquiry affords for design ideologies and pedagogy within the discipline to advance the dimensions of prescriptive architecture; encouraging creative responses, whilst also considering the unseen cognitive burdens architecture often places onto communities, cultures, and cities.
    • Effects of surface modification and graphene nanoplatelet reinforcement on adhesive joint of aluminium alloys

      Pawlik, Marzena; Lu, Yiling; Le, Huirong; University of Derby (Elsevier BV, 2020-03-13)
      In this study, the combinative effects of surface treatments and the reinforcement of graphene nanoplatelets (GNPs) on the adhesive joint of aluminium alloy were investigated. Aluminium alloy plates were treated with acetone cleaning, grit blasting, chemical etching, and phosphoric acid anodisation (PAA) under various conditions. The effects of hydrothermal sealing of the anodised aluminium were also studied. Surface energies of the treated aluminium plates were determined using contact angle measurements. The samples were then bonded with epoxy or GNPs reinforced epoxy adhesives. The bonding strength of the aluminium joints was measured by single lap shear tests. The joint strength was significantly affected by both surface treatment and the reinforcement of GNPs. For grit blasted and PAA samples with hydrothermal sealing, the joint strength increased by 64% and 57% respectively with 0.42 wt% of GNPs. Across all surface treatments, the highest average shear strength (17.6 MPa) was achieved for PAA samples with hydrothermal sealing and the addition of GNPs followed by PAA samples with no sealing and pure epoxy (17.0 MPa). Fractal surface images were analysed, and the correlation between epoxy infiltration behaviour, surface treatments and nano-reinforcement was critically discussed.
    • Quantification of carbon particulates produced under open liquid pool and prevaporised flame conditions: Waste cooking oil biodiesel and diesel blends

      Chong, Cheng Tung; Tian, Bo; Jo-Han, Ng; Fan, Luming; Wong, Kang Yao; Hochgreb, Simone; Shanghai Jiao Tong University; University of Derby; University of Southampton Malaysia; University of Cambridge (Elsevier, 2020-03-13)
      The soot volume fraction (SVF) of waste cooking oil (WCO) biodiesel and blends was quantified and compared under the same total carbon flow rate via two experimental setups, namely prevaporised diffusion jet flames and pool flames using extinction calibrated laser induced-incandescence (LII). The spatial SVF distribution shows that for diesel-rich fuels, soot formation peaks near the flame and is convected downstream, whereas biodiesel flames show a more evenly distributed SVF at the flame center region. An increase in biodiesel fraction in diesel results in a reduced propensity for soot, as evident in both pool and vapour flames. Comparison of the radial profiles of SVF along the centerline shows broader SVF profiles for pool flames, reflecting the longer residence times for soot diffusion and growth compared to vapour flames, which reflected the lower mass flux for the pool burner. The total soot produced from pool flames was found to be higher than vapour flame by a factor of two for the same fuel mass consumption rate. WCO biodiesel exhibited the lowest total SVF value regardless of flame type owing to the combined effects of lack of aromatic compounds and fuel chemistry. The soot primary particle sizes produced by WCO biodiesel show lower mean diameter values by a factor of approximately 1.5 compared to diesel-produced soot. The pool flames produced carbon particulates of larger mean diameter by around 22% and 8% for diesel and WCO biodiesel, respectively, relative to the counterpart vapour flames, as a result of extended soot surface growth period.
    • Optimization of a wearable thermoelectric generator encapsulated in polydimethylsiloxane (PDMS): A numerical modelling

      Soleimani, Zohreh; Zoras, Stamatis; Ceranic, Boris; Cui, Yuanlong; Shahzad, Sally; University of Derby; University of Sheffield (IEEE, 2020-03-05)
      To mitigate climate change attributed to the electricity generation, there have been tremendous efforts in replacement of fossil fuels by renewable energies in the electricity sector. For this purpose, wearable thermoelectric generators (WTEGs) are the most promising direct and green power generation technique for portable electronics. In spite of extensive research, there is a trade-off between flexibility of WTEGs and their power output. Thus, the aim of this research is to improve the performance of a flexible WTEG through differing the thermal conditions around the hot and cold junctions. Accordingly, the PDMS substrate of a flexible WTEG is segmented into two layers, whereas each layers are individually filled with different fillers. Accordingly, three different patterns are proposed for the segmentation. Then, by means of COMSOL Multiphysics software, the output voltage and power of the specified patterns are analyzed and compared with those of an original flexible WTEG. Results concluded that releasing the thermoelectric legs from PDMS coating can remarkably improves the output voltage as well as its power generation. In addition, with regard to the segmentation pattern, adding fillers to the PDMS layers has a twofold effect on the voltage and power generation. Precisely, thickness of each segments should be taken into consideration for selecting an appropriate filler. This work paves the way for enhancing the performance of flexible WTEGs, which ultimately leads to a low carbon and energy efficient electricity generation.
    • Dual-fuel operation of biodiesel and natural gas in a model gas turbine combustor

      Chong, Cheng Tung; Chiong, Meng-Choung; Ng, Jo-Han; Tran, Manh-Vu; Medina, Agustin Valera; Józsa, Viktor; Tian, Bo; Shanghai Jiao Tong University; Meng-Choung Chiong; University of Southampton Malaysia; et al. (ACS Publications, 2020-02-17)
      The dual-fuel combustion characteristics of palm biodiesel/methyl esters (PME) and natural gas (NG) in a model gas turbine swirl flame burner are investigated at a thermal power of 9.3 kW. The PME is atomized into a spray, while the gaseous NG is premixed with the main bulk swirling air before entering the combustion chamber. The dual-fuel PME/NG flame structure is similar to the single-fuel PME, where the sooty flame brush is noticeably absent. The PME and PME/NG flames emit higher peak intensity of OH* and CH* radicals as compared to diesel at the same equivalence ratio. Dual-fuel operation results in lower NO but higher CO at ϕ = 0.9 as compared to pure diesel and PME spray flames. The higher CO emission level for dual-fuel is attributed to poor mixing and incomplete combustion as a result of reduced air flow. At a leaner operation of ϕ = 0.65, enhanced turbulence due to higher bulk air flow results in improved mixing, lowering the overall CO but increasing the NO emissions because of the more intense flame core. The study shows that optimization of the multiphase dual-fuel injection system is needed to achieve low emissions in a gas turbine combustor.
    • Descriptive framework for simulation-aided sustainability decision-making: a delphi study

      Gbededo, Mijoh A; Liyanage, Kapila; University of Derby; University of Strathclyde (Elsevier, 2020-02-13)
      Making an effective sustainability decision at every stage of a product life cycle is key to achieving a holistic sustainable product development. The extant literature highlights the challenges and lack of effective tools for determining the impact of manufacturing processes on the environmental, economic and social dimensions, as well as the interdependence of the outcome of one dimension on the other. This research paper identifies methodologies, tools, and approaches that can be integrated into a single descriptive framework to enable both assessment and analysis of the aspects of the three sustainability dimensions. The paper also details the development of the framework using inductive methods and conceptual synthesis of key sustainability approaches and a Delphi study involving panels of international researchers and practitioners in the field of sustainable manufacturing. The framework can provide a platform for both practitioners and sustainability analysts to build impact analysis models that will support effective sustainability decision-making. It will also enable a clear perspective of the required elements, processes and indicators that need to be considered in sustainable manufacturing design and assessments.
    • Rutting resistance of asphalt pavement mixes by Finite Element modelling and optimisation

      Phuong Ngo, Chau; Nguyen, Van Bac; Nguyen, Thanh Phong; Bay Pham, Ngoc; Le, Van Phuc; Hung Nguyen, Van; University of Transport and Communications, Campus in Ho Chi Minh City, Vietnam; University of Derby (Bilingual Publishing Co., 2020-01-14)
      Asphalt pavement rutting is a major safety concern and is one of the main distress modes of asphalt pavement. Research into asphalt pavement mixes that provide strong resistance for rutting is considered of great significance as it can help provide extended pavement life and significant cost savings in pavement maintenance and rehabilitation. The objectives of this study are to develop numerical models to investigate the rutting of asphalt concrete pavements and to find optimal design of asphalt pavement mix for rutting resistance. Three-dimensional Finite Element models were first developed to simulate both the axial compression and wheel track testing in which a visco-elastic-plastic material model was used to predict the rutting of the asphalt concrete pavements. A strain hardening creep model with the material parameters developed from experimental testing was employed to model the time-dependent characteristics of the asphalt concrete pavements. The results were validated against the previous experimental wheel track test results of different pavement mixes. Finally, optimisation techniques using the Design Of Experiments method were applied to the simulation rutting results by varying creep parameters to identify their effects on rutting resistance in order to obtain an optimal asphalt pavements mixes. The results of this paper clearly demonstrate an efficient and effective experimental-numerical method and tool set towards optimal design for asphalt concrete pavements for rutting resistance.
    • Design of heat sinks for wearable thermoelectric generators to power personal heating garments: A numerical study

      Soleimani, Zohreh; Zoras, Stamatis; Cui, Yuanlong; Ceranic, Boris; Shahzad, Salome; University of Derby; University of Sheffield (IOP Science, 2020-01-01)
      To mitigate climate change attributed to the built environments, there have been tremendous efforts to improve air conditioning systems in the buildings. The possibility of harvesting body heat as a renewable energy source to power a wearable personal heating system is investigated. The aim of this study is to integrate a wearable personal heating system with a thermoelectric generator (TEG) that harvests the body heat which is used to convert it into electricity. Moreover, the interaction between the TEG configuration and power output is studied. The power generation of TEG system is obtained by COMSOL Multiphysics software. The simulation results concluded that all the four proposed heat sink configurations can improve the power output of the wearable TEG at 1.4 m/s and 3m/s compared to that of the reference model. Furthermore, the perforated and trapezium shapes of heat sinks have a significantly better performance in comparison to conventional heat sinks.
    • Energy assessment and economic sensitivity analysis of a grid-connected photovoltaic system

      Cui, Yuanlong; Jie, Zhu; Meng, Fanran; Zoras, Stamatis; University of Nottingham; University of Derby (Elsevier, 2019-12-30)
      This paper presents techno-economic assessment results of a grid-connected photovoltaic (PV) system for domestic building application. The PV system electricity output, energy conversion efficiency and cell temperature are explored based on the local weather condition, the system life cycle cost is evaluated with full account of the life of assets, volatile economic fluctuations, uncertainty influence factors, net present value (NPV) and discounted payback period (DPP) under Feed-in Tariff (FiT) scheme, the annual savings and payback time are compared for the FiT and new Smart Export Guarantee (SEG) schemes. Technical analysis results indicate that the system is capable of fulfilling the building electrical energy demand from April to October, and the extra electricity of 1530.23 kWh is exported to the grid in this period. The life cycle cost assessment results illustrate that the system achieves a NPV of £1335.32 and has a DPP of 9.34 years under the FiT scheme. Moreover, the sensitive analyses reveal that the high discount rate decreases the system NPV whereas the high initial cost leads to long payback period to realize the positive NPV. Furthermore, the FiT is the most cost-effective solution for PV system and has the shortest DPP compared with the SEG.
    • Exploring educational advantage in the UK via graduate employment of joint honours degrees by examining pre-university tariff and degree classification

      Pigden, Louise; Moore, Garford; University of Derby (Emerald, 2019-12-17)
      In the UK, the majority of university students specialise and study just one subject at bachelor degree level, commonly known in the UK as a single honours degree. However, nearly all British universities will permit students if they wish to study two or even three subjects, so-called joint or combined honours degrees, internationally known as a double major. The purpose of this paper is to explore the relationship between graduate employment, pre-university educational attainment and degree classification achieved. The study also explored student choice with respect to university prestige. The authors analysed the complete data set provided from the Higher Education Statistics Agency Destination of Leavers from the Higher Education survey, and combined this with data from the POLAR4 quintiles, Universities and Colleges Admissions Service (UCAS) tariff points and degree classification. The data were analysed to establish whether there was a difference in the choices and highly skilled graduate employment of the joint honours students, focussing particularly on Russell Group and Post-92 Universities, in order to build on previous published work. For any UCAS tariff band, the higher the POLAR4 quintile the higher the rate of highly skilled destination. Russell Group outperform the Post-92 graduates in their rates of highly skilled destinations, for any tariff band and for both joint and single honours degrees. Higher POLAR4 quintile graduates are more likely to study at the Russell Group, with this effect increasing the higher the UCAS tariff. With the exception of first class honours graduates from Post-92 universities, joint and single honours from the Russell Group have a higher rate of highly skilled destination than Post-92 in the next higher degree classification. Low POLAR4 quintile students with high UCAS tariffs are “under-matching” and there is an impact on their graduate employment as a result. This study adds new insights into joint honours degrees and also reinforces the literature around educational advantage and achievement prior to university, and the impact on graduate employment. Educational disadvantage persists over the course of a university degree education, from the perspective of gaining graduate employment. Higher quintile graduates are proportionately more likely to achieve the highest degree classifications, and proportionately less likely to achieve the lowest classifications, than graduates from the lower quintiles. Joint honours graduates are less likely to achieve a first class honours degree than single honours, and this will affect their rate of highly skilled destination.
    • A review on recent developments of thermoelectric materials for room-temperature applications

      Solemaini, Zohreh; Zoras, Stamatis; Ceranic, Boris; Shahzad, Sally; Cui, YUANLONG; University of Derby; University of Sheffield (Elsevier, 2019-12-13)
      Wearable thermoelectric generators (TEGs) emerge as a viable renewable energy source, which directly convert the heat dissipated from human skin into electricity. Extensive reviews have been conducted on the efficiency of thermoelectric materials (TE) as the dominant element of TEGs. TE materials are categorised as inorganic, organic, and hybrid. Each of these reviews focused on either a specific type of TE materials, or on a certain specification (i.e. flexibility) of them. However, less attention has been paid to comprehensively review all these types without taking into account a certain specification. Therefore, the purpose of this paper is to summarize the progress and current state-of-the-art research on the three types of TE materials respecting their TE properties and efficiency at 300K, which is the operating temperature of wearable TEGs. Concerning the inorganic TE materials, the results show that Bi0.4-xSb1.6+xTe3 and Bi2Te2.7Se0.3 are the most optimal TE materials, which exhibit the greatest efficiencies at room temperature. In addition, it is remarkably more efficient to replace polymer based TE composites with carbon based TE composites in the organic and the hybrid types. In total, this comprehensive review paves the way for researchers to find out the most suitable TE materials at room temperatures.