Linear Sweep Research Articles

A computer-generated plan to develop an intelligent biosensor for investigation of the inhibition of renin by aliskiren: A journey from inhibition to biosensing

For the first time, a novel electrochemical biosensor was fabricated based on modification of a rotating glassy carbon electrode with multi-walled carbon nanotubes-ionic liquid, and molecularly imprinted polymers (MIPs) in which renin (Rn), and aliskiren (AK) were used as templates. By immersion the biosensor in Rn, AK, and their binary system (AK-Rn) solutions, the species (Rn, AK, and AK-Rn) were entrapped within the pathways of the MIPs. These processes and investigation of the inhibition of the Rn by AK helped us to obtain higher electrochemical signals for a good monitorization of the system. The effects of experimental parameters on response of the biosensor to AK were optimized by a small central composite design to obtain the highest response. Hydrodynamic cyclic voltametric (HCV), hydrodynamic differential pulse voltammetric (HDPV), and hydrodynamic linear sweep voltammetric (HLSV) data obtained and recorded in order to be analyzed by classical methods and multivariate curve resolution-alternating least squares (MCR-ALS) as an advanced chemometric method. The results of molecular dockings, classical and chemometric analyses confirmed that the Rn was strongly inhibited by the AK which was good evidence to develop a novel biosensing system for determination of Rn. A novel biosensor was developed for determination of the Rn which had an acceptable performance in determination of Rn in the range of 0–9 fM. This approach opened a new way for investigation of enzymes' inhibition, and developing a new generation of electrochemical biosensors for medical and biomedical applications.

The influence of rice bran oil and nano-calcium oxide into bitumen as sustainable modifiers

Bio-oils are increasingly used to enhance petroleum bitumen’s intermediate and low-temperature characteristics regarding their economic and environmental benefits. Research has shown a beneficial impact of nanomaterials on altering bitumen’s high-temperature characteristics. The present study uses a mixture of rice bran oil and nano-calcium oxide to improve the performance of bitumen in all three temperature conditions. Rice bran oil was added to pure bitumen at doses of 3, 5, and 7 % relative to the weight of bitumen. The rheological tests (dynamic shear rheometer, multiple stress creep recovery, linear amplitude sweep, and bending beam rheometer) demonstrated that using rice bran oil in bitumen enhanced its performance at intermediate and low-temperatures but declined its performance at high-temperatures. Therefore, to improve the performance at high-temperatures, the bituminous sample containing 5 % rice bran oil was combined with 1, 3, and 5 % nano-calcium oxide, followed by repeating the rheological tests on them. The samples modified with nano-calcium oxide showed increased friction and shear stress, viscosity, and rutting parameters. Besides, the samples exhibited reduced sensitivity to aging compared to the bio-oil samples. However, the non-recoverable creep compliance and percentage of recovery showed improvements. The fatigue life of bio-oil samples decreased after adding nano-calcium oxide. However, the fatigue life remained higher than the base bitumen sample when adding 1 % nano-calcium oxide. Fourier-transform infrared spectroscopy analysis showed that a new chemical reaction occurred due to adding nano-calcium oxide to bitumen containing rice bran oil. Besides, the scanning electron microscope image revealed that the nano-calcium oxide particles are uniformly and homogeneously distributed within the bitumen sample containing 5 % rice bran oil. Consequently, the mix containing 5 % rice bran oil and 3 % nano-calcium oxide increases the resistance against high-temperature failures and improves the low-temperature performance compared to the base bitumen sample.

Adsorption and estimation of As (III) from wastewater using cross linked Chitosan-STPP nanoparticles with voltammetric analysis computrace, isotherms, and kinetic study

Chitosan (CS) is a naturally occurring polycationic linear amino polysaccharide produced commonly through the deacetylation of chitin. This study describes the synthesis of Chitosan (CS) modified with sodium tripolyphosphate (STPP) using an efficient coated Cross-linked method. The study investigated the efficacy of chitosan-tripolyphosphate (CS-STPP) nanoparticles for the efficient adsorption of As (III) ions from a wastewater solution. The effect of initial Arsenic (III) ion concentration, solution pH, and temperature on adsorption efficiency was thoroughly investigated. The highest adsorption capacity of CS-STPP nano adsorbents for As (III) was found to be 39.8 mg/g and 39.6 mg/g, respectively, at pH 5.5, and a temperature of 30 °C. The FESEM, SEM, HRTEM, XRD, FTIR, DLS, and TGA results indicated that the adsorption process of As (III) was chemically dominating. As (III) Determine with the anodic linear sweep voltammetry 797 VA Computrace (Metrohm). The Langmuir parameters of 40.9 mg/g and 1000 L/mg were found for maximum adsorption capacity, which indicated monolayer adsorption on a homogeneous site, Freundlich isotherm is applicable for multilayer adsorption onto heterogeneous sites. The thermodynamic study showed that the adsorption of As (III) by CS-STPP was spontaneous, feasible, and exothermic at temperatures ranging from 30 °C to 50 °C. The kinetic model indicated that the adsorption processes persist well to the pseudo-second-order kinetics model. The reaction is suitable for a pseudo-second-order model, it indicates an inclination for chemisorption. Adsorption-desorption processes are determined efficiency of bio adsorbent by several physicochemical cycles. All results indicate that the prepared CS-STPP nanoparticles might be considered a cost-effective adsorbent for removing As (III) from wastewater.

Synergetic effect of Ni substitution and induced porosity: Enhancing the electrocatalytic performance of cobaltite towards OER and MOR in alkaline medium

The quest for sustainable and efficient energy conversion technologies has intensified research into advanced materials for electrochemical reactions, such as the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). Transition metal oxides have emerged as promising catalysts due to their abundance, low cost, and adjustable electronic properties. Among these, Nickel (Ni)-based compounds are particularly noteworthy for their catalytic activity and stability. This research paper explores the crucial impact of Nickel (Ni) substitution and introducing porosity on the valence states of metal ions and their mass transport in the context of OER and MOR. In this study, we present a step-by-step surfactant (Brij 58) assisted synthesis approach for the preparation of mesoporous Co3O4 and NiCo2O4. The synthesised material has been physiochemically characterised by Fourier transform Infrared Spectroscopy (FTIR), Scanning electron microscopic/Energy-dispersive X-ray spectroscopy (SEM/EDS) and High-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry (ICP-MS) analyses. Additionally, the impact of these alterations on electrocatalytic activity, reaction kinetics, and electrochemical stability during OER/MOR has been explored by Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), Tafel, Electrochemical Impedance Spectroscopy (EIS) and chronoamperometric experiments. Mesoporous NiCo2O4 exhibits exceptional electrocatalytic performance with current densities of 46.8 mA/cm2 for OER and 214.5 mA/cm2 for MOR at 550 mV. By shedding light on the intricate interplay between metal substitution, porosity, and valence states, this research aims to provide valuable insights for the evolution of enhanced cobaltite electrocatalysts for sustainable water splitting and MOR.

A step toward Molnupiravir, COVID-19 Antiviral, detection using Cauliflower-Like cobalt Sulfide-Decorated carbon nanotube modified glassy carbon electrodes

Inhibiting the replication of COVID-19 viruses, Molnupiravir (MOL) has drawn extensive attention as an efficient antiviral medication during the global coronavirus pandemic. Adjusting the antiviral drug dosage is at the leading edge of achieving the optimum therapeutic effects while avoiding unwanted side effects. Developing inexpensive, highly-sensitive analytical methods, benefiting from high reliability and fast response of prime significance in monitoring and quality control of MOL in various matrices. Herein, an innovative strategy is developed to fabricate high-performance MOL sensing platforms through a facile and scalable approach. Accordingly, multi-walled carbon nanotubes (MWCNTs) are first drop-casted on the surface of glassy carbon electrode. Afterward, cauliflower-like cobalt sulfide nanosheets are electrodeposited onto the MWCNT-casted electrode. The MOL-sensing ability of the prepared sensing platforms is evaluated using various electrochemical methods. Under the optimal experimental conditions, two linear responses within broad detection ranges of 0.5 – 16 µM and 16 – 90 µM are obtained using the linear sweep voltammetry technique. A detection limit of 0.16 µM with a maximum sensitivity of 0.63 µA µM−1 in parallel to a relative standard deviation of 6.3 % is also achieved. Having the merit of high MOL sensitivity compared to other coexist interferences in human body fluids, together with fast response time, long-term stability, excellent repeatability, and high reproducibility, makes the fabricated electrode promising for reliable, fast, and accurate MOL monitoring.

Conducting Carbon Black Nano‐Filler Doped Polymer Electrolyte for Electrochemical Application

AbstractThis study provides a development of polymer electrolytes with an emphasis on their use in electrochemical devices. In present study we develop a new conducting carbon black (CB) powder dispersed into polyethylene oxide (PEO) polymer electrolyte using solution cast method. Various characterization techniques such as Impedance spectroscopy technique (EIS), Fourier transform infrared spectroscopy (FTIR), and Window stability (LSV) Linear sweep voltammetry has been studied in detail. The maximum ionic conductivity polymer electrolyte was at 0.05 wt%. of CB with σ value 1.20×10−5 S/cm. Finally the prepared CB dispersed polymer electrolyte using maximum conductivity sample is sandwiched between electrodes to fabricate an Electric double layer capacitor and Dye‐sensitized solar cell which show highest electrical capacity value of 68.5 F/gm at 5 mV/s respectively and 2.97 % efficiency shown by solar cell at 1 sun condition.

Improving Asphalt Binder Durability Using Sustainable Materials: A Rheological and Chemical Analysis of Polymer-, Rubber-, and Epoxy-Modified Asphalt Binders

When exposed to sun radiation and heat, asphalt binders age, resulting in reduced flexibility, cracking, and pavement failure. Given the increasing demands of traffic, environmental concerns, and resource scarcity, highway agencies and researchers are actively seeking solutions that meet performance requirements and demonstrate awareness of using non-renewable resources. Epoxy asphalt (EA) promotes sustainability concepts due to its production at significantly lower mixing and compaction temperatures, enhanced durability, improved serviceability, reduced maintenance needs, and successful recycling and reuse in hot asphalt mixtures. Crumb rubber, a widely recognized recycled waste tire material, is considered a viable option for promoting sustainability and enhancing asphalt binder properties. This study aims to enhance the durability and long-term performance of asphalt binders by utilizing sustainable materials. Six types of asphalt binders were employed: PG 67-22 base asphalt binder; styrene–butadiene–styrene (SBS)-modified PG 76-22 and PG 88-22H (3.5% and 7.0% dosage rates, respectively); a hybrid PG 76-22CS-modified asphalt binder prepared with SBS and crumb rubber modifiers; and 25EAB and 50EAB epoxy-modified asphalt binders prepared at 25 and 50% dosage rates, respectively. Results indicate that the sustainable asphalt binders PG 76-22CS, 25EAB, and 50EAB demonstrated comparable or superior performance compared to SBS-modified asphalt binders, as measured by rutting and fatigue factors. Additionally, epoxy asphalt binders had better anti-aging and cracking resistance, as shown by the outcomes of Fourier-transform infrared spectroscopy and linear amplitude sweep tests, respectively. This study contributes valuable insights into the potential of sustainable materials to enhance the overall performance and resilience of asphalt binders.

Research on Fatigue Performance of Fast-Melting SBS/Epoxy Resin Composite-Modified Asphalt

A high-performance composite modifier ER-SBS-T was prepared through the mixing of epoxy resin with a fast-melting styrene–butadiene–styrene modifier (SBS-T) to enhance material properties. This study evaluated the fatigue characteristics of ER-SBS-T-modified asphalt using a linear amplitude sweep test, and 70# base asphalt, SBS-modified asphalt, and SBS-T-modified asphalt were used as control groups. The fatigue life of ER-SBS-T-modified asphalt was determined according to viscoelastic continuous damage (VECD) theory. The findings indicated that as the ER-SBS-T modifier content increased, both the maximum value and the cumulative damage limit value increased, while the rate of change of decreased. At strain levels of 2.5% and 1%, the fatigue life of the modified asphalt improved with increasing ER-SBS-T content. However, at a strain level of 5%, the modified asphalt exhibited no significant trend in fatigue life across different ER-SBS-T contents. ER-SBS-T-modified asphalt with a modifier content of >10% demonstrated favorable fatigue performance suitable for practical engineering applications.

Exact solution for the electrical response of a constant phase element with a series resistance to linear voltage sweep

A resistance Rs in series with a constant phase element (CPE) of frequency-dependent impedance given by the power law function Zc(s)=1/(Cαsα) is commonly used for the analysis of steady-state frequency response data exhibiting non-purely capacitive behavior. This is the case in most (bio)(electro)chemical systems including dielectrics, batteries, supercapacitors, capacitive deionization units, biological tissues and bioelectrodes. Passing to the time domain, the current, voltage and charge of the system are governed by differential equations with non-integer, fractional-order operators. The purpose of this study is to provide the exact analytical expressions for the electrical response of an Rs-CPE model under linear sweep voltammetry with the use of the Laplace transform method. The electrical variables are expressed in terms of special functions regularly encountered with fractional calculus such as the Fox’s H-function and the Mittag-Leffler function, and can be used for modeling non-ideal devices as well as extracting their characteristic parameters.

Pulsed galvanostatic electrodeposition of tellurium nanostructures on stainless steel from copper anode slimes plating bath: Effect of pulse parameters

The electrochemical behavior of Te in alkaline media was determined by cyclic voltammetry and linear sweep voltammetry measurements. It indicated that TeO32− ion was first reduced to Te(s), then to Te22− ion. For the first time, the pulsed electrodeposition of tellurium on stainless steel has been studied in an alkaline bath and the effect of duty cycle, frequency, and current density on current efficiencies and morphology were indicated at room temperature. Pulse duty cycles ranging from 10 to 75%, frequencies ranging from 10 to 100 Hz, and current densities ranging from 7.5 to 30 mA/cm2 were employed. The morphology of the electrodeposition of tellurium samples was characterized by SEM. The results showed that due to increasing side reactions at higher current density, the current efficiency decreased with increasing current density. The results of Scanning Electron Microscopy (SEM) cleared that more compact structures with lower porosity were observed for the electrodeposits at lower current densities and less compact samples were obtained at higher current densities. It has been found that the current efficiency of tellurium plating decreases as the pulse duty cycle increases from 10% to 75%. Maximum current efficiency has been observed at 10% duty cycle. The study of the effect of duty cycle on morphology showed that the samples synthesized at a duty cycle of 10% and 25% have approximately similar appearance and particle size. With more increasing of duty cycles to 50 and 75% due to increasing hydrogen evolution rate and H2 bubbling at the electrode surface the morphology has been changed remarkably. The current efficiency of the deposit tellurium exhibited a strong dependence on the frequency. As frequency increases, the current efficiency almost decreases. In most cases, the maximum current efficiency is obtained at a 10 Hz frequency. The study of the effect of frequency on morphology showed that hydrogen evolution plays a significant role in the morphology formation of samples obtained at low pulse frequency (10 Hz), two processes of hydrogen evolution and anisotropic growth have key roles in morphology formation at medium pulse frequency (50 Hz) and anisotropic growth is the mechanism of morphology formation at high pulse frequency (100 Hz).

Electrochemical detection of nalbuphine drug using oval-like ZnO nanostructure-based sensor

Monitoring pharmaceutical drugs in various mediums is crucial to mitigate adverse effects. This study presents a chemical sensor using an oval-like zinc oxide (ZnO) nanostructure for electrochemical detection of nalbuphine. The ZnO nanostructure, produced via an efficient sol-gel technique, was extensively characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV–visible spectrophotometry, and fourier transform infrared spectroscopy (FTIR). A slurry of the ZnO nanostructure in a binder was applied to a glassy carbon electrode (GCE). The sensor's responsiveness to nalbuphine was assessed using linear sweep voltammetry (LSV), achieving optimal performance by fine-tuning the pH. The sensor demonstrated a proportional response to nalbuphine concentrations up to 150.0 nM with a good regression coefficient (R2) and a detection limit of 6.20 nM (S/N ratio of 3). Selectivity was validated against various interfering substances, and efficacy was confirmed through real sample analysis, highlighting the sensor's successful application for nalbuphine detection.

Fatigue performance analysis of fine aggregate matrix using a newly designed experimental strategy and viscoelastic continuum damage theory

Fine aggregate matrix (FAM), as the matrix phase in asphalt concrete (AC), significantly affects the fatigue behavior of AC. To accurately assess the mechanical properties of FAM, a newly designed experimental strategy for FAM testing was developed, and the viscoelastic continuum damage theory (VECD) theory was applied to analyze FAM’s fatigue cracking characteristics. In this study, a dumbbell-shaped geometry for dynamic shear rheometer testing was designed and verified through the FE-aided method. Subsequently, three AC mixtures’ FAM specimens with this special geometry were fabricated for the frequency sweep and linear amplitude sweep tests. Results showed that the specially designed specimens effectively capture the viscoelastic and fatigue properties of FAM with high replicability. Analyses based on the VECD theory indicated that FAM of porous asphalt (FAM(PA13)), featuring a higher asphalt content, exhibits a significant reduction in pseudo stiffness with increasing damage at the initial stage, but the reduction rate diminishes as damage progresses when compared to the other two FAMs. It was speculated that the higher aggregate content in FAM of dense-graded AC mixture (FAM(AC20) induces stress concentrations in the asphalt mastic near the protrusion areas of aggregates, thereby rendering the sample more susceptible to damage. The proposed methods will be readily extended to characterize other mechanical properties of FAM.

A framework to identify fatigue failure of asphalt binders under multiple aging levels using linear amplitude and time sweep testing

ABSTRACT The identification of fatigue failure can significantly affect the determination and prediction of fatigue life for a given asphalt binder. In this work, different approaches for identifying the fatigue failure on linear amplitude sweep (LAS) and time sweep (TS) are compared, especially for highly-aged asphalt binders. The candidate methods include traditional 50% or 80% reduction in pseudo-stiffness parameter (denoted as C0.5 and C0.2), peak stored pseudo-strain energy (PSE), peak C × N and peak phase angle. For asphalt binder at multiple aging levels, peak C × N is found to be effective in defining fatigue failure of TS testing. Meanwhile, peak stored PSE is suitable as the failure definition of LAS because it can capture the benefit of polymer modification and has a high accuracy for fatigue life prediction. Nf in strain-control TS test determined by different failure definitions shows that aging can increase the fatigue resistance at early-aged levels and then decrease the fatigue resistance at highly-aged levels. In general, the selected failure definitions have little influence on the trend of Nf with age levels. The purpose of this work is to select the logical failure definitions of asphalt binder under multiple aging levels.

Enhanced Photoelectrocatalytic Activity of CuO/CuNb2O6 Heterojunction Photocathodes for Efficient Solar Water Splitting

AbstractCuNb2O6 (CNO), a novel ternary metal oxide, has garnered much attention since it has a modest bandgap and potentially high current density. However, the reported photocurrent density so far is still much lower than the theoretical value. In this study, a CuO/CNO photoelectrode heterojunction was synthesized for the first time by using a solution‐based spray pyrolysis method. The properties of the heterojunction were investigated through various characterization techniques, including Mott‐Schottky analysis, time‐resolved photoluminescence, surface photovoltage analysis, chopper linear sweep voltammetry, and electrochemical impedance spectroscopy. The optimized maximum photocurrent density of the CuO/CNO heterojunction was ~0.75 mA/cm2 at 0.4 V vs. reversible hydrogen electrode (RHE), which is 2.8 times higher compared to the bare CNO photocathode. The improvement is attributed to the enhanced transport properties of charge carriers and promoted better separation of photo‐generated electrons and holes in the photoelectrode by the heterostructure. By the generation of heterojunctions, this work provides a new foundation for the design and construction of photocathodes with high charge separation efficiencies. This is also useful for future studies on water decomposition using heterojunctions as photoelectrode materials.

Effect of carbon fiber structure of Marimo carbon on polymer electrolyte fuel cell performance

Fibrous carbon has attracted attention for use as a carbon support of polymer electrolyte fuel cells (PEFC). In this study, Marimo carbon (MC), a fibrous carbon, was used as the carbon support. The MC has a higher order structure in which many carbon nanofilaments (CNFs) are grown on the surface of diamond particles (dia.). The MC was synthesized by the contact reaction between a Ni supported oxidized diamond (Ni/O-dia.) and CH4 gas, the carbon source of the CNFs. The flow rate of the CH4 gas during the MC synthesis altered the structure of the CNFs. A thick CNFs was observed in the MC with a low CH4 gas flow rate, which was not observed in the MC with a high CH4 gas flow rate. The MC with the thicker CNFs had wider interspaces between the CNFs and higher Pt supporting amounts. Electrochemical measurements of the Pt support MC (Pt/MC) were evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and current–voltage (I–V) measurements. The lower CH4 gas flow rate of the MC indicated faster charge transfer. The MC structural and charge transfer changed with the flow rate of the CH4 gas altered the electrochemical active surface area (ECSA), the oxygen reduction reaction (ORR) catalytic activity and the I–V performance of the Pt/MC.

Rapid Electronic Transport Channel of Co‐P with Mo in a Heterostructure Embedded with P, N Dual Doped Porous Carbon for Electrocatalytic Oxygen and Hydrogen Evolution

AbstractWe developed a molybdenum (Mo)‐doped cobalt (Co)‐heterostructure embedded on a phosphorous (P) and nitrogen (N) dual‐doped porous carbon which exhibits an intrinsic electronic transport channel of Co to Mo and P. The P,Mo,O−Co/PNC/NF (NF=Nickel foam) electrode offers 335 mV overpotential at 10 mA cm−2 in OER as compared with PMA‐ZIF67‐NC/NF and ZIF67‐NC/NF electrode with an overpotential of 357 and 373 mV respectively. Linear sweep voltammetry (LSV) of overall water splitting (OWS) supports that the current density gradually increased at a cell potential of 1.6 V with a maximum of 40 mA with a corresponding cell potential of 1.79 V at a current density of 10 mA cm−2. Density functional theory (DFT) calculations for water adsorption on optimized [111] surface of Co, CoMo, and CoMoP2 with adsorbed H2O and corresponding lattice determine the electron density difference of [111] surface with adsorbed H2O for Eads (eV) 4.23 corresponds to adsorption energy for CoMoP2. XANE‐EXAFS spectroscopy of P,Mo,O−Co/PNC at Co K edge and Mo K edge suggests the presence of higher valence of both Cox+ and Mox+ without metallic Co and Mo and Co−P and Mo−P bonds as major structural units due to phosphidation as determined by R‐space FT‐EXAFS spectra.

The Influence of Metal Impurities on NiOOH Electrocatalytic Activity in the Oxygen Evolution Reaction

AbstractThe energy transition and the implementation of new electrochemical technologies will result in an increased reliance on critical raw materials for electrodes. Their large‐scale application will ultimately mean working with lower grade materials. Here we study the influence of metal impurities on nickel foam electrocatalysts. We do this by electrodepositing known amounts of first‐row transition metals (Cu, Cr, Mn, Fe, Co and Ni) on nickel foam and studying their performance in the oxygen evolution reaction (OER) as a model reaction. The electrodes’ performance is studied using cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel analysis, stepwise chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Combining these results with microscopy analysis, we show that even small amounts of transition‐metal impurities have profound effects on the catalytic performance of nickel electrodes. The changes affect the OER onset potential (the energy that the system requires to convert OH– to O2) and the Tafel slope of each electrode (the electrode's initial activity in the OER onset region). Our results highlight the implications of such impurities on electrode design and future large‐scale application.

PEMFC Electrochemical Degradation Analysis of a Fuel Cell Range-Extender (FCREx) Heavy Goods Vehicle after a Break-In Period

With the increasing focus on decarbonisation of the transport sector, it is imperative to consider routes to electrify vehicles beyond those achievable using lithium-ion battery technology. These include heavy goods vehicles and aerospace applications that require propulsion systems that can provide gravimetric energy densities, which are more likely to be delivered by fuel cell systems. While the discussion of light-duty vehicles is abundant in the literature, heavy goods vehicles are under-represented. This paper presents an overview of the electrochemical degradation of a proton exchange membrane fuel cell integrated into a simulated Class 8 heavy goods range-extender fuel cell hybrid electric vehicle operating in urban driving conditions. Electrochemical degradation data such as polarisation curves, cyclic voltammetry values, linear sweep voltammetry values, and electrochemical impedance spectroscopy values were collected and analysed to understand the expected degradation modes in this application. In this application, the proton exchange membrane fuel cell stack power was designed to remain constant to fulfil the mission requirements, with dynamic and peak power demands managed by lithium-ion batteries, which were incorporated into the hybridised powertrain. A single fuel cell or battery cell can either be operated at maximum or nominal power demand, allowing four operational scenarios: maximum fuel cell maximum battery, maximum fuel cell nominal battery, nominal fuel cell maximum battery, and nominal fuel cell nominal battery. Operating scenarios with maximum fuel cell operating power experienced more severe degradation after endurance testing than nominal operating power. A comparison of electrochemical degradation between these operating scenarios was analysed and discussed. By exploring the degradation effects in proton exchange membrane fuel cells, this paper offers insights that will be useful in improving the long-term performance and durability of proton exchange membrane fuel cells in heavy-duty vehicle applications and the design of hybridised powertrains.

Study of dielectric and interfacial properties of functional biopolymer-based electrolyte with enhanced conductivity for energy storage application

This study investigates sodium (Na+) ion-conductive biopolymer blend electrolytes with glycerol as a plasticizer for energy storage. Through FTIR, impedance spectroscopy, transference number measurement (TNM), and linear sweep voltammetry (LSV), we identify an optimal film for electric double layer capacitor (EDLC) application. Glycerol induces notable changes in polymer-salt interaction, evidenced by FTIR band shifts reflecting increased free ions. Impedance measurements show reduced bulk resistance with optimal plasticizer content, emphasizing the system's suitability for energy storage. The system exhibits high real permittivity relative to imaginary at lower frequencies, attributing to glycerol's dielectric constant and small bulk resistance. Loss tangent (tanδ) and Argand plots reveal the dominant ion conduction mechanism. Electrochemical assessments support the suitability of the film for EDLC applications, featuring a favorable transference number (tion = 0.94) and high decomposition voltage (2.6V). Cyclic voltammetry (CV) curves demonstrate effective EDLC device design with significant capacitance adaptability across varying scan rates (5.946 F/g to 24.074 F/g).

Anti-ageing and rheological performance of bitumen modified with polyaniline nanofibres

Asphalt pavements represent the great majority of roads worldwide. However, the bitumen physico-chemical properties change due to ageing processes during both the production and service life of the asphalt mixes. In recent years, a completely new trend has been observed in the road engineering industry oriented to extending the service life of roads, bringing direct economic, ecological and social benefits. This work presents the possibility of inhibiting ageing of road bitumen by using polyaniline nanofibers (PANI_NFs) as well as enhancing its rheological properties examined with Linear Amplitude Sweep (LAS) as well as Multiple Stress Creep and Recovery (MSCR) tests. These results show that the application of PANI_NFs maintains the primary penetration value of bitumen short-term and long-term aged road bitumen at 88 % and 52 %, respectively. Moreover, bitumen modification with PANI_NFs reduces the softening temperature increase by 33 % and 24 %, respectively, and the viscosity increase of road asphalt by 50 % and 25 %, respectively. PANI_NFs also stabilised the bitumen surface adhesion force, determined with AFM, consequently confirming the enhanced resistance to ageing processes. In addition, changes in the carbonyl index, sulphoxide index and aromaticity of bitumen demonstrated that PANI_NFs inhibit oxidation and aromatisation reactions of its components. The tests indicated a 4-fold decrease in the degree of bitumen component oxidation after short-term ageing and a 33 % decrease after long-term ageing. FTIR analysis also showed a reduction in the degree of bitumen component aromatisation process of 79 % and 76 % for short-term and long-term ageing, respectively. The LAS and MSCR test results also showed that PANI_NFs had a beneficial impact on the resistance of the bitumen to fatigue and rutting. Overall, the study results suggest that PANI_NFs consitute a promising modifier for bitumen in terms of ageing inhibition and performance characteristics.