Erping Zhou

Sandwich structures fabricated from an aluminium skinned foam enclosed within a carbon fibre reinforced composite structure have the potential application for high-performance on- and off-road automotive vehicles. The deformations and failure of these types of structures are presented, and results indicate that the application of aluminium face sheets with aluminium foam (AF) aids to prevent the delamination of the outer layers of carbon fibre reinforced polymers (CFRP). The load carrying capacity has been increased by utilising a manufacturing method to maintain the adhesion between the core and the skins until the failure stage is reached. The core shear and de-bonded issue associated with this type of sandwich structure can be addressed by this manufacture method. The peak average flexure load capacity of an aluminium foam sandwich structure (AFSS) with a completely wrapped around CFRP skin was 2800 N with a mass of 191 g. This compares favourably with previously used AFSS without the skins, which had a peak average load of 600 N and a mass of 125 g. An initial finite element model for comparison purposes has been developed to represent the structure’s behaviour and predict the associated failure loads. It is proposed that CFRP wrapped around AFSS enhances the structural performance without significant weight gain.

Maximum Power Point Tracking technologies are being used in traditional PV system charge controllers to enhance the power conversion efficiency. An MPPT controller will ensure power extracted from the PV panels during varying climatic conditions is always maximum. This will ensure that maximum power is flowing between the panel and load. As both Temperature and Irradiation levels vary during the day, maximum power point trackers are an inevitable component in a PV system. As solar energy holds a major share in renewable energy in the world market, an improvement in MPPT technique makes the efficiency of the PV system increase and in turn cost reduction possible. However, the efficiency of conventional MPPT Techniques suffers from failing in tracking MPPT at fast varying climatic conditions and falling in local maxima of maximum power point than global maxima. The issues of stability, tracking speed, and accuracy can be solved using intelligent MPPT techniques methods based on soft computing tools: Therefore, this paper aims to study and provide a comparative analysis of two AI-based MPPT techniques such as ANN and ANFIS. The MPPT techniques considered in this study are ANN and ANFIS. Performance evaluation is carried out using MATLAB Simulation. Experimental results indicate that the two methods ANN and ANFIS are more efficient than conventional MPPT techniques due to its capability to avoid local MPP and partially shaded conditions.
Maximum Power Point Tracking technologies are being used in traditional PV system charge controllers to enhance the power conversion efficiency. An MPPT controller will ensure power extracted from the PV panels during varying climatic conditions is always maximum. This will ensure that maximum power is flowing between the panel and load. As both Temperature and Irradiation levels vary during the day, maximum power point trackers are an inevitable component in a PV system. The renewable energy source has a vital role in supplying sustainable power to meet the rising electricity demands. However, the PV system performance heavily depends on environmental conditions. This, in turn, causes efficiency to be less and in turn higher cost. For maximum power to be transferred from the PV panels under varying climatic conditions PV systems should operate at Maximum Power Point.

The rapid uptake of energy harvesting triboelectric nanogenerators (TENGs) for self-powered electronics requires the development of high-performance tribo-materials capable of providing large power outputs. This work reports on the synthesis and use of aniline formaldehyde resin (AFR) for energy-harvesting applications. The facile, acidic-medium reaction between aniline and formaldehyde produces the aniline-formaldehyde condensate, which upon an in-vacuo high temperature curing step provides smooth AFR films with abundant nitrogen and oxygen surface functional groups which can acquire a tribo-positive charge and thus endow AFR with a significantly higher positive tribo-polarity than the existing state-of-art polyamide-6 (PA6). A TENG comprising of optimized thin-layered AFR against a polytetrafluomethylene (PTFE) film produced a peak-to-peak voltage of up to similar to 1000 V, a current density of similar to 65 mA m(-2), a transferred charge density of similar to 200 mu C m(-2) and an instantaneous power output (energy pulse) of similar to 11 W m(-2) (28.1 mu J cycle(-1)), respectively. The suitability of AFR was further supported through the Kelvin probe force microscopy (KPFM) measurements, which reveal a significantly higher average surface potential value of 1.147 V for AFR as compared to 0.87 V for PA6 and a step-by-step increase of the surface potential with the increase of energy generation cycles. The work not only proposes a novel and scalable mouldable AFR synthesis process but also expands with excellent prospects, the current portfolio of tribo-positive materials for triboelectric energy harvesting applications.

This paper aims to use machine learning methods to predict the service life of rotary lip seals to aid manufacturers and users improving the current maintenance procedures. Seals are widely used in most engineering applications. The knowledge of condition of seals throughout their working life is important due to the fact that they are often used on high value engineering products. As the current material properties of the seal and the working environment various, it is difficult to predict useful life of the rotary lip seal. In this paper, the factors relating to life of rotary lip seals are investigated and discussed. The application of machine learning methods using actual testing data in order to estimate the useful life of the seals has been presented. The early results show good agreement between actual and predicted values.

Electrospinning is a simple, versatile technique for fabricating fibrous nanomaterials with the desirable features of extremely high porosities and large surface areas. Using emulsion electrospinning, polytetrafluoroethylene/polyethene oxide (PTFE/PEO) membranes were fabricated followed by a sintering process to obtain pure PTFE fibrous membranes, which were further utilised against a polyamide 6 (PA6) membrane for vertical contact-mode triboelectric nanogenerators (TENGs). Electrostatic force microscopy (EFM) measurements of the sintered electrospun PTFE membranes revealed the presence of both positive and negative surface charges owing to the transfer of positive charge from PEO which further corroborated by FTIR measurements. To enhance the ensuing triboelectric surface charge, a facile negative charge-injection process was carried out onto the electrospun (ES) PTFE subsequently. The fabricated TENG gave a stabilised peak-to-peak open-circuit-voltage (Voc) of up to ~900 V, a short-circuit current density (Jsc) of ~20 mAm-2 and a corresponding charge density of ~149 μCm-2, which are ~12, 14 and 11 times higher than the corresponding values prior to the ion-injection treatment. This increase in surface charge density is caused by the inversion of positive surface charges with the simultaneous increase in the negative surface charge on the PTFE surface, which was confirmed by using EFM measurements. The negative charge injection led to an enhanced power output density of ~9 Wm-2 with high stability as confirmed from the continuous operation of the ion-injected PTFE/PA6 TENG for 30,000 operation cycles, without any visible reduction in the output. The work thus introduces a relatively simple, cost-effective and environmentally friendly technique for fabricating fibrous fluoropolymer polymer membranes with high thermal/chemical resistance in TENG field and an ion-injection method which is able to dramatically improve the surface charge density of the PTFE fibrous membranes.

This paper investigates design and implementation of Maximum Power Point Tracking (MPPT) algorithm for Photo Voltaic (PV) applications on Field-Programmable Gate Array (FPGA) platform. The algorithm is developed by means of Hardware Description Language (Verilog). Algorithms were simulated on MODELSIM software and synthesized using ALTERA Quartus II software. Furthermore, hardware implementation is done using ALTERA Cyclone II FPGA starter board to verify the performance of the designed algorithms. The paper will investigate whether FPGA is a suitable hardware platform for real time MPPT controller.

This paper investigates design and implementation of Maximum Power Point Tracking (MPPT) algorithm for Photo Voltaic (PV) applications on Field-Programmable Gate Array (FPGA) platform. The algorithm is developed by means of Hardware Description Language (Verilog). Algorithms were simulated on MODELSIM software and synthesized using ALTERA Quartus II software. Furthermore, hardware implementation is done using ALTERA Cyclone II FPGA starter board to verify the performance of the designed algorithms. The paper will investigate whether FPGA is a suitable hardware platform for real time MPPT controller.

Utilising an interfacial piezoelectric ZnO nanosheet layer, a significant enhancement in the power density is reported for the triboelectric nanogenerators (TENG) based on phase inversion membranes of polyvinylidene fluoride (PVDF) and polyamide-6 (PA6). At an applied force of 80 N, the TENG device incorporating electrochemically deposited ZnO nanosheets produces an output voltage of ~ 625 V and a current density of ~ 40 mA m−2 (corresponding a charge density of 100.6 μC m−2), respectively; significantly higher than ~ 310 V and ~ 10 mA m−2 (corresponding a charge density of 77.45 μCm−2) for the pristine TENG device. The enhancement in the surface charge density provided by the interfacial piezoelectric ZnO layer is also reflected in the high piezoelectric coefficient d33 (−74 pm V−1) as compared to the pristine fluoropolymer membranes (−50 pm V−1). For tribo-negative membranes incorporating the interfacial ZnO layer, piezoelectric force microscopy measurements further show enhanced domain size which can be attributed to the interfacial dipoledipole interaction with the ferroelectric polarisation of PVDF, which promotes the alignment with the polar axis of ZnO. Under compressive stress, the piezoelectric potential thus produced in the ZnO nanosheets provides charge injection on to the surface of ZnSnO3-PVDF membrane, improving the charge density, which in-turn significantly enhances the power density from 0.11 to ~ 1.8 W/m2. The TENG devices thus fabricated using a facile electrochemical deposition and phase inversion technique show enhanced output power without the need for high electric field poling or external charge injection process by relying on the coupling of triboelectric and piezoelectric effects.

This paper focuses on the mathematical modelling and simulation of Maximum Power Point algorithms to investigate tracking efficiency at different atmospheric conditions. This paper will review existing Maximum Power Point Tracking approaches. A 60W PV panel is modelled in MATLAB since panel current is taken as the input for maximum power point tracking. This paper presents a simulation based comparative study between two most popular techniques perturb and observe (P&O) and incremental conductance (InCond) to optimize the energy conversion efficiency of PV system.

Vertical contact-separation mode triboelectric generator (TEG) based on lead-free perovskite, zinc stannate (ZnSnO3)-polyvinylidene fluoride (PVDF) composite and polyamide-6 (PA6) membrane is demonstrated. For the 5 wt% PVDF-ZnSnO3 nanocomposites, the facile phase-inversion method provides a simple route to achieve high crystallinity and β-phase with a piezoelectric coefficient d33 of −65 pm V−1, as compared to −44 pm V−1 for pristine PVDF membranes. Consequently, at a cyclic excitation impact of 490 N/3 Hz, the PVDF-ZnSnO3/PA6 based TEGs provide a significantly higher voltage of 520 V and a current density of 2.7 mA m−2 (corresponding charge density of 62.0 µC m−2), as compared to the pristine PVDF-PA6 TEG which provides up to 300 V with a current density of 0.91 mA m−2 (corresponding to a charge density of 55.0 µC m−2). This increase in the electrical output can be attributed to not only the enhanced polarisation of PVDF by ZnSnO3 leading to an increase in the β-phase content, but also to the surface charge density increase by stress induced polarisation of ZnSnO3, leading to the generation of stronger piezoelectric potential. The work thus introduces a novel method of enhancing the surface charge density via the addition of suitable high polarisation piezoelectric materials thus eliminating the need for prior charge injection for fluoropolymer membranes.