Search Results (319)

The adoption of lithium-ion batteries (LIBs) as secondary rechargeable batteries across many industries, including consumer electronics, electromobility, industrial tools, and electrical energy storage, is on the rise. As lithium-ion batteries approach the end of their life, there is a need to assess them for the possibility of a secondary application or reuse for a less demanding application. The extra connections of individual cells, BMS, temperature sensors, and other components to form a compact battery pack pose a challenge for second-life assessment, which usually prefers to separate individual cells for testing before discarding very bad cells for recycling and grading cells with substantive capacity based on their remaining capacity. This is a high cost for the second-life assessment. This work seeks to investigate an approach that avoids dismantling the battery pack into individual modules, cells, and BMS by including a BMS feature that allows the capacity and power ratings to be rescaled onboard after its first use. A set of cells with different chemistries was used in this work: a nickel–cobalt–aluminium oxide cathode with a silicon-doped graphite anode (NCA-GS), a nickel–cobalt–aluminium oxide cathode and graphite, and a lithium–nickel–manganese–cobalt oxide (NMC) cathode with a graphite anode (NMC-G) with various ageing states and behaviours. Their internal resistance and capacity at the beginning and end of life were compared. The scaling factor was obtained by finding the square root of the ratio of the internal resistance at EOL to that at BOL. With the current obtained by multiplying the cycling current rate by the rescaling factor, the surface temperature profile of the aged cells during cycling became the same as the temperature at the beginning of life. The relaxation voltage after discharge to 0% SOC and charge to 100% SOC was used to set the low and high cut-off voltages, respectively. This contributed significantly to reduced ageing and to a lower temperature rise in the spent cells. This set the stage for rescaling or derating battery systems without separating the individual cells, which is a huge cost for second-life use of lithium-ion batteries. BMS can be designed with configurable voltage and current limits, so that when repurposed for a second life, only a simple configuration or firmware update may be necessary. Full article

This study presents an analytical–experimental investigation of the mechanical and tribological behaviour of two coating systems applied to deep, internally profiled cylindrical components manufactured via Electrochemical Rifling (ECR): a hard anodised aluminium oxide (AAO) coating on an aluminium alloy and a hard chromium coating on alloy steel. Experimental characterisation includes microhardness measurements, coefficient of friction determination, and controlled sliding wear tests. The chromium coating exhibits approximately 2.5 times higher microhardness and about 15% lower average coefficient of friction compared to the anodised aluminium layer, resulting in significantly improved wear resistance. Acceptable engineering agreement is observed between analytical predictions and experimental results. For chromium-coated steel, analytical predictions yield approximately 67,200–72,600 cycles, while the experimentally estimated value is about 36,200 cycles. For anodised aluminium, analytical predictions range from approximately 1688 to 2803 cycles, compared to an experimental value of about 2012 cycles. A conservative reliability-oriented criterion yields service lives of approximately 12,000 cycles for chromium coatings and 1000 cycles for anodised aluminium. Weibull-based analysis (R = 0.95) indicates service life ranges of approximately 9300–10,000 and 230–390 cycles, respectively. Full article

For cable compound manufacturers, accurate formulation fine-tuning is essential to ensure safety, long-term durability, and compliance with international standards for dielectric strength, volume resistivity, and environmental and thermal ageing. This work presents an experimental study demonstrating how minor additives can critically affect the performance of complex flame-retardant elastomeric formulations. The investigation focuses on the role of small amounts of zinc oxide (ZnO) in commercial cable compounds based on a crosslinked elastomeric matrix composed of ethylene–propylene monomer (EPM), ethylene–propylene–diene monomer (EPDM), and thermoplastic polyolefin elastomer (POE). The formulations contain aluminium trihydroxide (ATH) as the major filler, together with several minor additives. Among these, a phenolic antioxidant (AN01) acting as a metal deactivator is also present. The addition of ZnO in low amounts (2–5 phr) allowed the compounds to maintain a volume resistivity ≥ 10¹² Ω·cm in water at 100 °C. To elucidate the role of ZnO, a systematic set of formulations was prepared by varying the type and content of selected additives. The compounds were prepared by melt mixing in an internal mixer (Banbury type), followed by peroxide crosslinking via compression molding. Electrical characterization results indicate that ZnO interacts with the phenolic additive through surface adsorption, forming a coated particle with significantly reduced electrical conductivity. Optimal electrical performance was achieved when the ZnO-to-additive ratio corresponded to the minimum amount required for complete surface complexation. Full article

Silane sol was applied to seal the pores in a micro-arc oxidation coating, with the results proving that the treatment increased the anti-corrosion characteristics of aluminium alloy. Moreover, an electrochemical workstation was employed to test the open-circuit voltage, polarisation potential, and polarisation current of the samples. According to the results, after the aluminium alloy was treated with the micro-arc oxidation coating and underwent subsequent sealing treatment, the open-circuit potential increased from −0.64 to −0.44 V, the corrosion potential from −0.54 to −0.31 V, and the corrosion current density from 56.23 × 10⁻⁷ to 7.76 × 10⁻⁷ A. However, when samples were corroded by 1 mol/L HCl, the corrosion potential and corrosion current density decreased to −0.34 V and 20.42 × 10⁻⁷ A, respectively, proving that sealing the pores on the micro-arc oxidation coating only prevented substrate corrosion for a short time. In addition, slow-strain-rate stretching experiments were conducted to explore the mechanical performances of the samples, determining that the surface treatment had an insignificant effect on the stress of the aluminium alloy but had an important effect on its elongation, and when the surface of the alloy was treated with micro-arc oxidation coating, its elongation decreased from 28% to 26%. Full article

This study develops generalised equations to predict arsenic removal efficiency during adsorption using synthetic sand, based on two key factors: adsorbent dose and temperature. Previous experimental investigations demonstrated that iron oxide coated sand (IOCS), aluminium oxide coated sand (AOCS), and their mixtures are highly effective for arsenic removal. Best-fit equations were first derived for IOCS and AOCS at discrete temperatures as functions of dose concentration, and these were subsequently unified into single predictive equations capable of estimating removal efficiency across a wide range of temperatures and doses. The resulting models closely replicate experimental results, with correlation coefficients exceeding 0.99 for both IOCS and AOCS. Using the same methodology, an additional equation was developed for a 50:50 mixture of IOCS and AOCS, yielding a slightly lower but still strong correlation coefficient of 0.97. In contrast, linear proportioning of the individual IOCS and AOCS equations failed to accurately predict the removal efficiency of the mixed adsorbent, indicating that simple linear scaling is inadequate for representing the combined adsorption behaviour. Full article

This study evaluates the effects of Al₂O₃ and CeO₂ nanoparticles as additives to standard diesel and biodiesel fuels on the combustion and emissions characteristics of a CR diesel engine with split injection (pilot and main injections). Three nanoparticle dosing levels (50 ppm, 100 ppm, and 150 ppm) were compared with undoped standard diesel and biodiesel fuels. The results showed that the presence of both Al₂O₃ and CeO₂ in biodiesel increased the ignition delay of the pilot fuel by about 8.0% at low load and about 3.5% at high load. The addition of both nanoparticles to diesel and biodiesel fuels had an insignificant effect on the main injection fuel’s ignition delay, MBF50 position and combustion duration. The thermal efficiency was up to 1.0% lower. Al₂O₃ additive in diesel had no significant effect on NO_x emissions. CO emissions were higher by 4.4–7.5% in most cases. The Al₂O₃ additive in biodiesel reduced NO_x emissions by an average of 38%, 17.1%, and 9.4% at low, medium, and high engine loads, respectively. The reduction in CO emissions averaged 15%. The addition of CeO₂ nanoparticles to diesel fuel reduced NO_x emissions by 22.5%, 8.5%, and 3.1% on average across the corresponding load ranges. When the engine was operated on CeO₂-doped biodiesel, NO_x emissions were lower by an average of 25.7%, 9.6%, and 2.5% at low, medium, and high loads, respectively. Adding CeO₂ nanoparticles to diesel fuel increased CO emissions, whereas adding them to biodiesel significantly reduced CO emissions. Full article

The impending Euro 7 regulation will impose strict limits on brake particulate matter (PM) emissions from new light-duty vehicles, driving manufacturers to explore alternative rotor materials and/or surface treatments. This paper evaluates the friction and wear emission performance of both a laser-clad grey cast iron (GCI) rotor surface and a plasma electrolytic oxidation (PEO) treated aluminium surface compared to that of an uncoated GCI. Tests were conducted on a small-scale tribometer rig, which was specially adapted to measure airborne emissions while emulating the standard Worldwide harmonised Light vehicle Test Procedure (WLTP). The laser-clad coating was applied via extreme high-speed laser cladding to form an initial 430 L stainless steel layer, followed by a topcoat of 80/20 vol% 430L steel/TiC, both layers being c.100 micron thick. The PEO treatment applies a c.50 micron alumina coating to both a wrought and cast alloy, the latter being more suitable for the manufacture of full-size vented brake rotors. Results show that all rotor materials achieved a satisfactory coefficient of friction (CoF) against suitable low-metallic pad material, although the CoF for the wrought PEO-Al alloy was significantly higher at c.0.65 compared with c.0.50 for the other materials. The gravimetric wear of all the coated rotor surfaces after 8 WLTP cycles was almost undetectable, and pad wear was also significantly reduced. This improved wear resistance led to significant reductions in PM emissions, with the PM10 levels of the uncoated GCI reduced by around 75% for the laser-clad GCI and PEO wrought Al alloy, and by about 60% for the PEO cast Al alloy. When extrapolated to a full-sized passenger vehicle, the results indicated that both the laser-clad GCI and PEO-treated surfaces have the potential to meet the current Euro 7 emissions targets. Full article

A parabolic trough collector (PTC) is a linear concentrating system consisting of a parabolic-shaped reflector with a receiver tube positioned along the focal axis. In this study, the performance of a parabolic trough solar collector is evaluated, with aperture area, collector length, breadth, Rim angle, and inner and outer absorber diameters of 5.54 m², 3.65 m, 1.52 m, 70°, 0.048 m, and 0.05 m, respectively. The experiment was conducted at Ranchi, India (23.35° N and 85.30° E). During this day, marked by a cloudless sky, the ambient temperature ranged from 27 °C to 39 °C. The global solar radiation ranged from (630 W/m² to 975 W/m²), and the wind speed varied between (0.8 m/s and 1 m/s). Aluminium oxide (Al₂O₃) and Therminol VP-1-based nanofluid were employed as the working fluid. The different volume fractions of nanoparticles were taken, and the evacuated tube PTC performance was analysed. When Al₂O₃–Therminol VP-1 of varying concentration (0–4%) and mass flow rate of 0.041 kg/sec is used, it has been observed that the receiver’s heat transfer performance improved with an increment in nanoparticle volume fraction. Temperature-dependent properties were applied to the thermal efficiency, exhibiting a notable increase of approximately 7.2% when the volume fraction ascends from 0 to 4%. At elevated Reynolds numbers, the efficiency decreases compared to lower volume fractions. These results contribute to understanding the effect of nanoparticle concentration on PTC performance. Full article

This study reports on the performance of alumina-supported copper-based catalysts in the oxidative dehydrogenation of propane, with copper dispersed on two distinct commercial aluminium oxide supports made of micro- and nanosized alumina, respectively. The activity and selectivity of the two catalysts was investigated at temperatures between 250 and 550 °C. At a propane-to-O₂ ratio of 1:1, Cu/nanoAl₂O₃ achieves propylene selectivity of 35–48% at low temperatures (250–300 °C), while Cu/Al₂O₃ only exhibits activity starting at 350 °C with about 40% propylene selectivity. Altering the propylene-to-oxygen ratio to 3:1 enhances selectivity towards propylene in both catalysts, up to about 64% on Cu/Al₂O₃ at temperatures of 250–350 °C. The switch to the mild oxidant CO₂ boosts propylene selectivity to 100%. In case of Cu/nanoAl₂O₃, the rate of propylene formation doubles that of the obtained with O₂ used as oxidant. While with CO₂ the Cu/nanoAl₂O₃ catalyst retains 100% propylene selectivity up to 500 °C, on the less active Cu/Al₂O₃ cracking sets off already at 400 °C. The different size of copper particles in the two catalysts is seen as a primary factor determining the observed differences in the performance of the studied catalysts. Full article

This work examines the micromechanical response of Al₂O₃/IF-WS₂ (IF-inorganic fullerene-like) composite coatings formed on the EN AW 5251 aluminium alloy by anodic oxidation. The resulting amorphous oxide layer contains a nanopores system that can be filled with IF-WS₂ particles, provided the modifier is properly dispersed. Because commercial IF-WS₂ powders exhibit strong agglomeration, a high-intensity ultrasonic treatment was applied to enhance particle separation before incorporation. The influence of newly established incorporation parameters was assessed using a two-level experimental design. As part of the research, analyses of the microstructure, micromechanical, and sclerometric properties were performed. Cross-sectional SEM observations confirmed the presence of IF-WS₂ within the oxide structure and revealed differences in particle distribution, depending on the incorporation technique used. The results indicate that although microhardness and Young’s modulus are largely insensitive to the nanopowder incorporation method, the interaction between the anodising current density and the incorporation technique significantly influences the strain energy components and tribological response of the coatings. These findings suggest that appropriately selected processing parameters can be used to tailor the mechanical and tribological properties of Al₂O₃/IF-WS₂ coatings to specific loading conditions and functional requirements, rather than striving for a single, universal, optimal processing configuration. Full article

This study investigates the reaction thermodynamics of the sodium oxide-fluxed aluminothermic reduction of pyrolusite-based manganese ore under self-propagating high-temperature synthesis (SHS) conditions, using Si, Cr, and Cu as collector metals. The experimental results are compared with thermochemical equilibrium calculations using FactSage 7.3 thermochemistry software. Experimental mixtures were prepared with controlled additions of aluminium, sodium silicate, calcium oxide, and collector metals and heated to the ignition temperature in a muffle furnace preheated to 1350 °C. The resulting alloys and slags were analysed for bulk composition. Collector metals significantly influence alloy carbon saturation and manganese recovery. The individual reaction’s Gibbs free energy values and the gas–slag–metal equilibrium were calculated. Discrepancies between the experimental and equilibrium-predicted results highlight the kinetic factors of SHS processes, particularly with respect to aluminium uptake and manganese volatilisation. The main difference is the alloy’s aluminium uptake. The difference between the calculated and experimental aluminium levels is, in part, due to the higher partial oxygen pressure predicted in the gas–slag–metal equilibrium calculations, compared with that of the likely Al–Al₂O₃ governing reaction equilibrium. Short-circuiting of aluminium to the alloy is also a possible contributing factor. The findings provide insights into optimising feed formulations and process parameters for improved manganese recovery. Full article

Low soil nutrient availability and uptake negatively affect crop productivity in acidic soils. For example, phosphorus (P) availability is reduced by fixation of aluminium (Al) and iron (Fe) hydrous oxides and precipitation with soluble Al and Fe. In addition, soil acidity inhibits root growth, and application of agricultural lime ameliorates these challenges, thereby improving yields. However, resource-limited farmers in the Eastern Cape Province can rarely afford to procure lime and chemical fertilisers, which necessitates alternative approaches to addressing the challenge of low nutrient availability for crops. The present study explores interactions between cattle manure and mineral fertiliser applications coupled with arbuscular mycorrhizal fungi (AMF) inoculation on the agronomic performance of Amaranthus grown in acidic soil. The treatments were 100% cattle manure, 50% cattle manure + 50% NPK fertiliser and lime, 33% cattle manure + 33% NPK and lime + AMF, the recommended rate of mineral fertiliser and lime, AMF, and an absolute control. Cattle manure and mineral fertiliser application, including mixtures of their microdoses, coupled with AMF inoculation, significantly improved the growth and yield of Amaranthus species. Leaf tissue concentrations of N, P, K, Ca, Mg and Zn and their uptake, and selected residual soil properties and nutrients increased significantly following application of the treatments relative to the unfertilised control. The findings of this study imply that application of manure and mixtures of microdoses and mineral fertiliser, together with AMF, improve nutrient uptake and yield of Amaranthus and residual nutrients that benefit subsequent crops. Full article

Hard anodic oxide coatings on aluminium have long been used to enhance surface functionality. However, increasing industrial demands are driving the need for coatings with superior hardness, wear resistance, corrosion resistance and self-lubricating properties. Due to their porous structure, anodic oxide coatings can be modified by incorporating various nanoparticles. The properties of the modified coatings depend on both the type of nanoparticles used and the method employed to incorporate them. In this study, anodic oxide coatings were produced using direct and duplex methods on a semi-industrial scale to enable process control and potential industrial implementation. The coatings were modified with hard (Al₂O₃) and soft (CaCO₃, PTFE) nanoparticles in order to customise their functional properties. Their microstructure and chemical composition were characterised by SEM and TEM. Their microhardness, abrasion resistance and electrochemical behaviour were also evaluated. Among the tested production methods and methods for modifying nanoparticles, the duplex process incorporating Al₂O₃ particles proved to be the most promising. Its optimisation resulted in coatings with a microhardness of 430 HV0.05 and a mass loss of 9.4 mg after the Taber abrasion test, demonstrating the potential of this approach for industrial applications. Full article

The inherent limitations of conventional polyolefin separators, particularly their poor thermal stability and insufficient mechanical strength, pose significant safety risks for lithium-ion batteries (LIBs) by increasing susceptibility to thermal runaway. In this study, we developed a novel multilayer separator through sequential coating of a commercial polyethylene (PE) substrate with aluminum oxide (Al₂O₃), para-aramid (PA), and polyethylene wax microspheres (PEWMs) using a scalable micro-gravure process, denoted as SAPEAS, signifying a PE-based asymmetric structure separator with enhanced thermal shutdown and dimensional stability. The SAPEAS separator exhibits an early thermal shutdown capability at 105 °C, maintains structural integrity with negligible shrinkage at 180 °C, and demonstrates comprehensive performance enhancements, including enhanced mechanical strength (tensile strength: 212.3 MPa; puncture strength: 0.64 kgf), excellent electrolyte wettability (contact angle: 12.8°), a high Li⁺ transference number (0.71), superior ionic conductivity (0.462 mS cm⁻¹), outperforming that of commercial PE separators. In practical LFP|Gr pouch cells with ampere-hour (Ah) level capacity, the SAPEAS separator enables exceptional cycling stability with 97.9% energy retention after 1000 cycles, while significantly improving overcharge tolerance compared to PE. This work provides an effective strategy for simultaneously improving the safety and electrochemical performance of LIBs. Full article

The fabrication of undoped and aluminium-doped zinc oxide thin films on quartz glass substrates through the aqueous spray method is reported. The prepared aqueous precursor solutions containing Zn²⁺ and varying mole percentages (0, 2, 4, and 8%) of Al³⁺ complexes were spray-coated onto quartz glass substrates preheated at 180 °C. The as-sprayed films obtained were then heat-treated at 450 °C for 30 min in a furnace to produce the various thin films. The structural and optical properties of the resultant thin films were analysed using the X-ray diffractometer (XRD) and ultraviolet–visible (UV-Vis) spectrophotometer. The XRD results revealed that the fabricated thin films have a prominent peak correlating to the (002) Miller index, which is the preferred orientation of the zinc oxide hexagonal wurtzite phase. The fabricated thin films with a film thickness of approximately 189 nm absorb light in the visible region and have a transmittance of over 80% even after being doped with aluminium. The photocatalytic activities of the thin films were evaluated via visible light irradiation of an aqueous methyl orange solution, and the Al-doped ZnO thin films exhibited good photocatalytic activities, which resulted in an increase in the doping mole percentages of aluminium. Full article