Open Circuit Research Articles

Enhancing corrosion resistance of lightweight metal alloys through laser shock peening

In this study, we investigated the effects of laser shock peening (LSP) on the corrosion resistance of lightweight metal alloys, specifically AA6061 and AZ31. LSP was performed underwater, using a nanosecond pulse laser and without using a protective coating or layer on the workpiece. The corrosion behaviors of these alloys were analyzed through electrochemical tests, including open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The results demonstrated that LSP significantly improved the polarization resistance, and higher laser power intensities led to increased corrosion resistance and reduced corrosion rates. This enhancement in anti-corrosion performance is attributed to the formation of a protective oxide layer on the surface, acting as a barrier against corrosion. The findings underscore the potential of laser surface treatment as a viable technique for enhancing the corrosion resistance of lightweight metal alloys.

A Tribological Study of CrN and TiBN Hard Coatings Deposited on Cobalt Alloys Employed in the Food Industry

In this work, a comparative study of the tribological performance of two hard coatings, CrN/TiBN, was conducted for research purposes and industrial applications in food products, particularly for food packaging into cans using the double hermetic sealing process. CrN and TiBN coatings were successfully deposited on a base-cobalt metal substrate of a CoCrW commercial alloy using physical vapor deposition by arc evaporation (AEPVD) technology to improve the tribological properties of the commercial alloy, including wear and corrosion resistance, lower coefficient of friction, and overall durability. This research focuses on conducting scratch and abrasion wear resistance tests in dry conditions; specifically, it pursues to evaluate the wear corrosion properties, known as tribocorrosion performance, on CrN/TiBN hard coatings. The experimental results show that the CrN coating (2.9 μm) is slightly thicker than the TiBN coating (2.7 μm), with a 47 N critical load. It also shows a lower coefficient of friction (CoF) in a dry environment, while the TiBN coating showed total detachment and a high coefficient of friction in a dry environment condition. Tribocorrosion testing in brine aqueous solution indicated that CrN coating shows a high friction coefficient with a higher open circuit potential value (Ecorr), and TiBN shows the lowest corrosion potential (Ecorr) and the lowest friction coefficient. This suggests that CrN could provide better corrosion protection for commercial cobalt alloys and improve tool performance during the food canning process in brine environments.

The Transformative Role of Nano-SiO2 in Polymer Electrolytes for Enhanced Energy Storage Solutions

In lithium–polymer batteries, the electrolyte is an essential component that plays a crucial role in ion transport and has a substantial impact on the battery’s overall performance, stability, and efficiency. This article presents a detailed study on developing nanostructured composite polymer electrolytes (NCPEs), prepared using the solvent casting technique. The materials selected for this investigation include poly(vinyl chloride) (PVC) as the host polymer, lithium bromide (LiBr) as the salt, and silica (SiO2) as the nanofiller. The addition of nano-SiO2 dramatically enhanced the ionic conductivity of the electrolytes, with the highest value of 6.2 × 10−5 Scm−1 observed for the sample containing 7.5 wt% nano-SiO2. This improvement is attributed to an increased amorphicity resulting from the interactions between the polymer, salt, and filler components. A structural analysis of the prepared NCPEs using X-ray diffraction revealed the presence of both crystalline and amorphous phases, further validating the enhanced ionic transport. Additionally, the thermal stability of the NCPEs was found to be excellent, withstanding temperatures up to 334 °C, thereby reinforcing their potential application in lithium–polymer batteries. This work explores the electrochemical performance of a fabricated lithium-ion-conducting primary electrochemical cell (Zn + ZnSO4·7H2O|PVC: LiBr: SiO2|PbO2 + V2O5), which demonstrated an open circuit voltage of 2.15 V. The discharge characteristics of the fabricated cell were thoroughly studied, showcasing the promising potential of these NCPEs. With the support of superior morphological and electrical properties, as-prepared electrolytes offer an effective pathway for future advancements in lithium–polymer battery technology, making them a highly viable candidate for enhanced energy storage solutions.

Flexible polyester-embedded thermoelectric device with Bi2Te3 and Te legs for wearable power generation

This study presents an approach for powering wearable sensors by integrating nanostructured bismuth telluride (Bi2Te3 and Te legs) into flexible polyester substrates. The choice of polyester as the substrate is because it is widely used in clothing, especially in items such as shirts, blouses, dresses, and sportswear. This enables seamless integration with wearable devices. By capturing wasted body heat, our small and flexible thermoelectric generators (TEGs) offer long-term operation without the need to plug the batteries. We demonstrate the feasibility of using commercially available polyester for reproducible electrochemical deposition of highly oriented Bi2Te3 and Te material. Through electrodeposition, we embed Bi2Te3 and Te legs within the flexible polyester, creating a cost-effective and easily scalable hybrid system for wearable energy harvesting.Our optimized TEG design, which can be worn on the arm or forehead, achieves impressive power density compared to existing state-of-the-art solutions. With a mere 3.5 °C temperature difference, only two pairs of p- and n-type legs, and a thickness of approximately 15 µm, our TEG generates a maximum open circuit voltage of ∼0.1 mV and a maximum power density of ∼0.04 mW·K-1·cm−2. With 250 pairs, 10 mV can be reached. This cost-effective design also integrates electrical contacts, surpassing previous flexible TEG performances. These advancements make our TEGs suitable for driving microwatt-level electronic sensors and open new avenues for efficient energy harvesting in wearable applications.

A comprehensive investigation of oxygen/graphite carbon nitride smart Nano coatings for sustainable maintenance and sacrificial anode protection of mild steel

AbstractBACKGROUNDThis study enhancing the corrosion resistance of mild steel (MS) by incorporating photo‐catalyst‐doped graphitic carbon nitride (g‐C₃N₄) nano‐sheets containing silver (Ag) and oxygen (O₂) into a solar light‐active photoelectrochemical anticorrosion paint with polyester (PE). The objective is to provide sacrificial anode protection through visible light activation.RESULTSThe developed paint forms a uniform film on the MS surface, effectively providing anodic protection under visible light. Characterization techniques, including energy‐dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier‐transform infrared spectroscopy (FTIR), and UV–Vis spectroscopy, confirm the molecular structure of the nano‐sheets. Corrosion resistance, assessed through weight loss measurements and open circuit potential (OCP) tests, shows significant improvement with the addition of Ag/g‐C₃N₄ and Ag‐O₂/g‐C₃N₄ nano‐sheets at an optimized concentration of 15 mg. The protection efficiency is ranked as follows: O₂‐g/C₃N₄ > O‐g/C₃N₄ > Ag‐O₂/g‐C₃N₄ > Ag‐g/C₃N₄ > g‐C₃N₄. After 28 days of immersion in seawater, MS coated with O₂/g‐C₃N₄ exhibited the least weight loss, with an inhibition efficiency of up to 99%. Electrochemical impedance spectroscopy (EIS) further demonstrated enhanced coating resistance for the O₂/g‐C₃N₄ coating (Rct = 3.76 kΩ.cm2, Rcoat = 1.69 kΩ.cm2) compared to pure PE (Rct = 0.005 kΩ.cm2, Rcoat = 0.096 kΩ.cm2).CONCLUSIONThe synthesized O₂/g‐C₃N₄ and Ag‐O₂/g‐C₃N₄ nano‐sheets exhibit high surface areas and enhanced water dispersibility, which contribute to significant corrosion protection of MS. The electrochemical performance, including weight loss and OCP measurements, highlights the potential of these nano‐sheet photo‐catalysts in advancing corrosion resistance technologies, with broad implications for materials science and engineering applications. © 2024 Society of Chemical Industry (SCI).

Enhanced bioenergy production through dual-chamber microbial fuel cells: Utilizing citric acid factory wastewater and grape waste as substrates

IntroductionMicrobial fuel cell (MFC) is a variant of the bio-electro-chemical system that uses microorganisms as biocatalysts to generate bioenergy by oxidizing organic matter. Due to its two-prong feature of simultaneously treating wastewater and generating electricity, it has drawn extensive interest by scientific communities around the world. However, the pollution purifying capacity and power production of MFC at the laboratory scale have tended to remain steady, and there have been no reports of a performance breakthrough. Problem statementThis research was conducted to produce electricity and evaluate the efficiency of chemical oxygen demand (COD) removal from wastewater containing Citric Acid using a two-chamber microbial fuel cell without an intermediary. MethodologyIn this research, citric acid factory wastewater was used as the substrate, graphite as the electrode, Nafion membrane for proton transfer from anode to cathode, and grape waste as a carbon source. These Experiments were performed at room temperature and neutral pH. Also, the effect of three independent variables mixed liquor suspended solid (MLSS), Carbon: Nitrogen: Phosphorus stoichiometric ratio (COD:TKN:P), and grape waste on electricity production and wastewater treatment was investigated. Then, the optimal values of each variable were determined under favorable conditions for electricity generation and COD reduction. ResultsThe MFC was conducted at the optimal values of MLSS 1400 mg/L, the stoichiometric ratio of COD:TKN:P 140:10:1, and the grape waste dose of 1.4 g/L. At these conditions, the obtained maximum power density and current density were 18228.10 mW/m2 and 244.44 mA/m2, respectively. The maximum COD removal was 72% achieved in the values of MLSS 1400 mg/L, the stoichiometric ratio of COD:TKN:P equal to 260:10:1, and 1.4 g/L of grape waste. The maximum open circuit voltage was also recorded as 678 mV, obtained at MLSS 3000 mg/L, the stoichiometric ratio of COD:TKN:P equal to 200:10:1, and for a grape waste dose of 2 g/L. ConclusionThe results of this research showed that the use of grape waste to supply glucose to microorganisms in the MFC system has a significant effect on increasing energy production and COD removal, and it is recommended to conduct additional research in the future to improve the efficiency. However, scalability and practical application potential of these integrated technologies are the challenges towards their real-world applications in small scale trials.

Flexible high electrochemical collagen/lignin composite hydrogel for sensing and supercapacitor applications

Synthesis of polymer-based highly conductive hydrogels from natural and renewable sources with robust mechanical performances in flexible electronics remains a great challenge. In this research, a dynamic redox system is designed by using collagen (CL), sulfonate lignin (SL), acrylic acid (AA), and Al3+ to synthesize CL/PAA/SL/Al hydrogels. The formation of effective complexes of Al3+ with the abundant functional groups of CL, SL and PAA, the prepared hydrogel delivers various specific properties, for example, excellent ionic conductivity (4.61 S·m−1), stretchability and antimicrobial performance. The CL/PAA/SL/Al hydrogel demonstrates good mechanical strength, while the maximum tensile strength of the hydrogels is ∼604 kPa at a stretching of 1254 %, and the maximum compressive strength is ∼0.45 MPa, with the maximum stretching of 59.6 %. The CL/PAA/SL/Al hydrogel acts as a flexible strain sensor with high sensitivity. Enough hydroxyl and carboxyl groups in the hydrogels are essential for delivering the maximum 191 mV of open circuit voltage (Voc) rendered during moisture spraying. The supercapacitor assembled from CL/PAA/SL/Al hydrogel manifests specific capacitance (Cs), maximum energy density (Ed) and power density (Pd) of 268.75 F·g−1, 23.89 Wh·kg−1 and 2.4 kW·kg−1, respectively. The supercapacitor can retain its capacitance of 95.8 % after 5000 consecutive charge-discharge cycles.

Performance optimization of FASnI3 based perovskite solar cell through SCAPS-1D simulation

The article provides a detailed look at the fabrication of a high-performance structure for FASnI3-based perovskite solar cells (PSCs). The FTO/CeO2/FASnI3/CuI/Au structure is designed using the Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D) to investigate the fabricated PSC's performance. This investigation's main objective is to improve PSCs performance by using non-traditional Hole transport layer (HTL) and Electron transport layer (ETL) materials, such as CeO2 and CuI, which have both been the subject of limited research. Moreover, the investigation seeks to determine the impact of several perovskite layer characteristics, including bandgap (Eg), electron affinity (χ), acceptor density (NA), thickness (t), and defect density (Nt). Additionally, this study also investigates the effect of various back contact work functions. Significant improvements in solar cell parameters, such as power conversion efficiency (PCE) from 22.06% to 24.87% and current density (Jsc) from 26.0274 to 30.675 mA/cm2, were observed by optimizing the device's parameters. In contrast, the fill factor (FF) and open circuit voltage (Voc) decreased their values from 86.13% to 87.10% and 0.9843 to 0.9308 V, respectively. These findings show that our designed solar cell structure performs better than those with conventionally used HTLs and ETLs. Consequently, this study highlights the potential benefits of lead-free PSCs and presents fresh opportunities for their development and use in various solar applications.

Lignin-derived Fe–N–C electrocatalyst with 3D porous structure for efficient oxygen reduction reaction

Developing low-cost, high-performance oxygen reduction reaction (ORR) catalysts is crucial for the commercialization of fuel cells and zinc-air batteries. Herein, we report a lignin-derived Fe/N co-doped 3D porous carbon electrocatalyst Fe-NLC-1 as an alternative to commercial Pt/C catalysts, which was synthesized by a green and facile in situ carbonization strategy. Fe-NLC-1 exhibits higher oxygen reduction activity with a half-wave potential (E1/2) of 0.90 V vs. RHE than commercial 20 wt% Pt/C (E1/2 = 0.85 V) in the alkaline conditions, as well as excellent methanol tolerance and stability. Furthermore, the Zn-air battery loaded with Fe-NLC-1 exhibits a maximum power density of 125 mW cm−2, an open circuit voltage of 1.477 V, and stable discharge performance, which are comparable or even better than the commercial Pt/C. This study highlights the potential of biomass-derived porous carbon materials for the development of high-performance ORR electrocatalysts.

Resilient Reinforcement Learning for Voltage Control in an Islanded DC Microgrid Integrating Data-Driven Piezoelectric

This research study presents a resilient control scheme for an islanded DC microgrid (DC MG) integrating solar photovoltaic (PV), battery storage (BESS), and piezoelectric (PE) energy harvesting modules. The microgrid (MG) case study represents an energy hub designed to provide electricity for lighting systems in transportation, roads, and other infrastructure. To enhance practicality, the PE is modeled using the real data captured from a traffic simulator. The proposed reinforcement learning (RL) method was tested against four severe and unexpected failure scenarios, including short circuit at the load side, sudden and severe change of load, open circuit, and converter failure. The performance of the controller was quantitatively compared with a conventional PI controller. The results show marginal improvement in one scenario and significant improvement in the other three, suggesting that the proposed scheme is a robust candidate for microgrids with high levels of uncertainty, such as those involving solar and PE harvesters.

Direct torque control of a dual star induction generator based on a modified space vector PWM under fault conditions

Recent studies have shown that electrical systems in wind power conversion are subject to a 67 % failure rate, and conventional three-phase generators are considered to be the most sensitive to these faults. Induction generator current harmonics are a major source of torque ripples causing acoustic noise and vibrations. These ripples can progressively increase under faulty operating conditions. In six-phase machines, there is appearance of high harmonic currents in the air gap as space harmonics. Power electronic converters are also subject to faults, the most common being Short-Circuit (SC) and Open-Circuit (OC) faults. SC faults cause large peaks in the line currents, which trigger the protection devices, resulting in a complete shutdown of the production system. OC faults, on the other hand, cause imbalances in the phases, but the system remains in operation.Direct Torque Control (DTC) based on Space Vector Modulation (SVM) at constant switching frequency is an effective solution to tackle induction generator current harmonics. This paper proposes a DTC combined with a Proportional Integral Fuzzy Logic Controller (PIFLC) optimized by Particle Swarm Optimization (PSO) in order to overcome the problems of torque ripples. Furthermore, using Vector Space Decomposition (VSD) and the Modified Space Vector Pulse Width Modulation (MSVPWM) strategy, a significant reduction of harmonics in the air-gap can be achieved.Simulations were carried out under MATLAB/Simulink, and the results obtained demonstrate the superiority of the proposed DTC-PIFLC-PSO controller in terms of robustness against wind speed variations and under faulty switch conditions in the power converter of the Dual Star Induction Generator (DSIG) generator. In addition, a comparative study with the classical PI controller is presented to show the effectiveness of the DTC-PIFLC-PSO controller against faults with a significant reduction in the Total Harmonic Distortion (THD) during both faulty and non-faulty conditions.

A Noninvasive Sliding Mode Observer Based Approach for Detecting Open-Circuit Faults in HERIC Inverters

This article presents a new technique for detecting and localizing the open-circuit (OC) faults in the semiconductor switches of the Highly Efficient and Reliable Inverter Concept (HERIC) converter. It is a transformerless Photovoltaic (PV) inverter based on the full-bridge topology, with two extra switches on the AC side called ac bypass switches. The proposed method uses a sliding mode observer (SMO) to detect faults in the AC bypass switch and main switches of the full bridge inverter. To diagnose OC faults in the AC bypass leg, two parallel SMOs are created based on the converter’s state space model. Similarly, two SMOs are designed for the main switches. A residual is generated by combining the observed and measured grid currents to accurately locate the OC fault within the inverter system. To localize the faulty main switch, once the fault is detected the inverter is reconfigured and based on the grid current the faulty switch is identified. A major benefit of this method is that it does not rely on additional sensors for fault diagnosis, making the system more robust. The effectiveness and reliability of this approach are demonstrated through simulation studies. In addition, a laboratory prototype is developed to validate the practical applicability of the method.

Unlocking the power of Dryopteris filix mas extract: A green solution for corrosion inhibition in A210Gr carbon steel in acidified 3% wt. NaCl environment

This study investigates the corrosion inhibition effectiveness of Dryopteris filix-mas L. (DFM) extract for A210Gr carbon steel in a 3 % NaCl solution. The DFM ethanolic extract was successfully prepared and comprehensively characterized using a combination of spectroscopic and physicochemical techniques, including HPLC, FTIR, and NMR (1H and 13C). These analyses confirmed the presence of key phenolic compounds, with Quercetin-3-O-diglucoside (Q3ODG) being the major component, comprising 82.14 % peak area as identified by HPLC. The extract, obtained via an economical ethanol extraction method, exhibited a maximum inhibition efficiency up to 88 % at a concentration of 400 ppm, as determined through electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), potentiodynamic polarization (PDP), and weight loss measurements. Temperature studies revealed a drop in efficiency to 70.14 % at 323 K, indicating a temperature-sensitive inhibition mechanism. Extended immersion times led to a slight decrease in efficiency due to partial desorption, though significant protection remained after 72 h. The primary corrosion inhibition mechanism was determined to be physisorption, following the Langmuir isotherm model, with a ΔGads0 value of − 24.02 kJ/mol, indicating a spontaneous adsorption process. Thermodynamic analysis revealed an increase in Ea from 22.11 kJ/mol (blank) to 56.61 kJ/mol (400 ppm), confirming the formation of a strong protective barrier. Surface characterization techniques, including FTIR, XRD, SEM, and AFM, further confirmed the presence of a protective film rich in polar organic compounds. Complementary Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) studies provided detailed insights into the molecular interactions, highlighting the key role of hydrogen bonding and van der Waals forces in the adsorption of Q3ODG onto the steel surface. These findings underscore the potential of DFM extract as an effective and sustainable corrosion inhibitor, advancing the application of biocompounds in corrosion control and encouraging further exploration of their industrial applications and environmental benefits.

Facile construction of polyacrylate membranes with pendent zwitterionic side-chains for high proton conduction

Designing high-performance proton exchange membranes for fuel cells has received tremendous interests and acquired plentiful fruits. However, the complicated preparation process and consequently high cost limit their practical application. This study endeavored to facilely construct a novel type of proton exchange membrane based on polyacrylates which decorated with pendant zwitterionic groups. Chemical structure and micro-morphology of these newly prepared membranes, namely SBPA-x (x = 0, 20, 30,40), were characterized by 1HNMR, FT-IR, XPS, SEM and AFM. Swelling ratio, water uptake and ion exchange capacity were found to be positively correlated with the contents of zwitterionic groups. The hydrophilic zwitterionic groups in the membrane formed a continuous water pathway, which contributed to the proton conductivity. Particularly, SBPA-40 membrane showed the highest proton conductivity of 78.6 mS/cm and the smallest activation energy Ea as 16 kJ/mol at 80 °C and 90 % relative humidity. On the other hand, the other application properties, such as thermal stability, mechanical property and oxidation stability, were also evaluated. Results demonstrated that all the membranes possessed good thermal stability within 300 °C and presented satisfactory mechanical performance by bending and twisting. Besides, the observed power density and open circuit voltage of SBPA-40 membrane were 58.3 mW/cm2 and 0.77 V at 30 °C. In conclusion, the zwitterionic polyacrylate membranes could have prospective application in proton exchange membrane fuel cells.

Machine learning-assisted SCAPS device simulation for photovoltaic parameters prediction of [formula omitted] perovskite solar cells

Perovskite solar cells (PSCs) have garnered significant research attention because of their remarkable surge in power conversion efficiency (PCE) surpassing 26% within a short timeframe. However, the widespread adoption of these highly efficient PSCs is hampered by the inherent toxicity associated with lead (Pb)-based perovskites, which currently dominate the field. Researchers have explored alternative cations like Ge2+ and Sn2+ Owing to their identical oxidation states to Pb2+, paving the way for lead-free PSC development. By examining the critical factors influencing CsSnI3 thin film solar cells’ performance as well as their interdependencies, this work seeks to improve the efficiency of these devices. To do so, machine learning algorithms (ML) are employed to figure out the critical factors influencing the completion of CsSnI3 solar cells. A new dataset of 7870 data points is generated through simulations with SCAPS-1D to effectively depict the perovskite solar cell. Five ML regression algorithms are thereafter utilized to predict the photovoltaic parameters of solar cells, such as the fill factor (FF), open circuit voltage (VOC), short circuit current (JSC), and PCE. The study shows that random forest (RF) and decision tree (DT) are the best performing algorithms, among which DT produces high accuracy and low error for predicting the PCE with a coefficient of determination R2 of 0.99, Pearson’s coefficient (Rvalue) of 0.99, Spearman’s correlation coefficient (ρ) of 0.99 and root mean square error of 0.08 on the testing set. Finally, this study offers valuable guidance for further experiment optimization by shedding light on the optimal device dimensions and essential components.

A more accurate Co-Content function calculation, using alternative integration methods, for Current–Voltage curves measured in the zero volt to open-circuit voltage range

AbstractIn this article, the application of the Newton–Cotes quadrature formula, the 3/8 rule, the Boole’s rule, and order 5 and 6 integration techniques, are explored to more accurately calculate the Co-Content function, of Current–Voltage (IV) measurements done between 0 V and the open circuit voltage, which include a percentage noise of the short circuit current. Their impact on the extraction of the five photovoltaic devices’ parameters (within the one-diode model) is investigated and reported. The shunt resistance, series resistance, ideality factor, and photocurrent can be obtained with less than 10% error, using these integration techniques and 101 measured points per volt, when the percentage noise is 0.05% or less, of the short circuit current. It is not possible to obtain the saturation current with less than 10% error. These integration techniques are implemented in photovoltaic devices, such as solar cells and single-crystalline silicon, CdTe, CIGS, and heterojunction with intrinsic thin-layer solar panels IV curves, to extract the five solar cell parameters.

Electrochemical behavior and microstructure of diffusion welding of zirconium alloy and super duplex stainless steel

In this study, the effect of welding temperature on interface microstructure, mechanical properties, and electrochemical behavior of diffusion welded joints (DWJs) of zirconium alloy (ZrA, Zr702 grade) and super duplex stainless steel (2205 duplex stainless steel grade) were investigated. Alloys were welded in a vacuum atmosphere at four different temperatures (800, 850, 900, and 925 °C) for 75min under 4MPa compressive pressure. The optical, scanning electron microscopy, electron probe micro-analyzer, and X-ray diffraction techniques were used to characterize the interfacial microstructure of the DWJs. Layers of intermetallics were formed along the welded interface at 850 °C and above welding temperatures. At 850 °C, a single reaction layer (phase mixture of ZrFe2+ZrCr2) was observed; however, bilayers (ZrFe2+ZrCr2 and Fe2Zr+FeZr3 phase mixtures), and triple layers (ZrFe2+ZrCr2, Fe2Zr+FeZr3, and β-Zr+FeZr3 phase mixtures) were observed at the welded interface of the joints processed at 900 and 925 °C, respectively. Width of the reaction layer (phase mixtures) increases with an increase in the welding temperature. The DWJs processed at 900 °C reach the maximum joint strength of ~312MPa along with ~6.4% ductility. For corrosion analysis, studies of the base alloys and DWJs in 0.1mol/L HCl and 0.1mol/L NaOH solutions separately using electrochemical techniques, such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization were undertaken.

Microbial Fuel Cell Based on Ensifer meliloti

The world’s growing energy crisis demands renewable energy sources. This issue can be solved using microbial fuel cells (MFCs). MFCs are biocatalytic systems which convert chemical energy into electrical energy, thereby reducing pollution from hazardous chemical compounds. However, during the development of MFCs, one of the most significant challenges is finding and assessment of microorganisms that generate sufficient redox potential through metabolic and catalytic processes. In this research, we have used Ensifer meliloti (E. meliloti) bacteria to design MFCs based on consecutive action of two redox mediators (9,10 - phenanthrenequinone (PQ) and potassium ferricyanide), which transferred charge between E. meliloti bacteria and graphite rod electrode. A viability study of E. meliloti culture showed that PQ significantly inhibits the growth of bacteria at 0.036 mM. Cyclic voltammograms were registered in the presence of 20 mM of potassium ferricyanide and different concentrations (0.036 and 0.071 mM, 0.11 mM, 0.14 mM, 0.172 mM, 0.32 mM) of PQ. Four days of lasting assessment of the microbial fuel cells in two-electrode systems showed that the maximal open circuit potential during the experiment raised from 174.9 to 234.6 mV. Power increased from 0.392 to 0.741 mW m−2.

Molecular engineering on tyrian puprle natural dye as TiO2 based fined tuned photovoltaic dye material: DFT molecular analysis

In this research, molecular modification is employed to see the enhancement in the efficiency of Tyrian Purple (TP), a natural dye, for organic photovoltaic materials.By using Density Functional Theory (DFT) based molecular modeling, seven new structures are designed with pi spacer to extend electron donor moieties. Teheir Frontier Molecular Orbital (FMO) analysis demonstartes their charges with a similar pattern of distributions over their Highest Occupied and Lowed Unocuupied Molecular Orbitals (HOMO/lUMO). This analysls also show their energy gaps (Egaps) to range around 2.97-3.02 eV. Their maximum absorption wavelength (λmax) demosntartes 486-490 nm range to indicate their tendency of absorbing light efficiently. Their Transition Density Matrix (TDM) analysis also reveals their facile electronic transitions without a significant charges over spacers. From calculating their photovoltaic paramters, their Light Harvesting Efficiency (LHE) reaches to 72.4-95.5 %. Also their Open Circuit Voltage (Voc) varies across 1.16-1.34 V. It is found that dyes actively adsorb onto TiO2 clusters to demonstrate their promise for tuning their Conduction Band (CB). This research is an effort for to evaluate the structural correlations to the developm photovoltaic materials through molecular-level design and optimization.

Electrical Performance and Degradation Analysis of Field-Aged PV Modules in Tropical Climates: A Comparative Experimental Study

Performance degradation is a prevalent phenomenon in solar photovoltaic systems globally, with varying aging profiles and effects depending on environmental and climatic conditions. This paper presents an extensive investigation of the electrical performance, aging mechanisms, and degradation analysis of field-aged PV modules under the tropical climate of Malaysia. Utilizing a combination of visual inspection, I-V curve measurement, and thermal imaging techniques, this research provides a comprehensive assessment of the electrical and thermal properties of field-aged PV modules from two locations in Malaysia over extended periods (8 years at UMPSA and 10 years at Pasir Mas). The multi-faceted approach of the study allows for a deeper understanding of the degradation process, offering insights into the causes and effects of higher current and lower voltage in aged modules. The study found the average annual degradation rates at UMPSA were 0.3% for open circuit voltage (Voc), 0.23% for short circuit current (Isc), 0.81% for maximum power (Pmax), and 0.35% for fill factor (FF) and at Pasir Mas, the average annual degradation rates were 1.124% for Voc, −0.166% for Isc, 1.276% for Pmax, and 0.43% for FF. The study also found that monocrystalline silicon (m-Si) panels experienced an average power degradation of 6.48%, while polycrystalline silicon (p-Si) panels showed a higher degradation of 12.76%. However, Thermal imaging revealed significant temperature variations across the modules, with hotspots reaching up to 11.2 °C above cooler areas in UMPSA panels and an even more pronounced 26.1 °C difference in Pasir Mas modules. These temperature disparities highlight the uneven heat distribution and potential performance issues in the panels. This research contributes to the understanding of PV module degradation in tropical climates and aligns with sustainable development, climate change mitigation efforts, and SDG 7 by promoting sustainable energy solutions.