Energy Applications Research Articles

Lesion size index-guided radiofrequency catheter ablation using an impedance-based three-dimensional mapping system to treat sustained atrial tachycardia in a horse.

Sustained atrial tachycardia at an atrial rate of 191/min on the surface ECG was detected in a 6-year-old Warmblood mare. The vectorcardiogram obtained from a 12-lead ECG suggested a caudo-dorsal right atrial origin of the arrhythmia. Impedance-based three-dimensional electro-anatomical mapping, using the EnSite™ Precision Cardiac Mapping System revealed a clockwise macro-reentry around a line of conduction block in the caudomedial right atrium. Ten radiofrequency applications were applied to isolate the caudal vena cava myocardial sleeves at a power of 35 W and mean contact force of 14 ± 3 g until a lesion size index of 6 was reached. Sinus rhythm was restored at the first energy application. Successful isolation was confirmed by demonstrating entrance and exit block. Holter monitoring 5 days post-ablation revealed no abnormalities. To date, 9 months after treatment, no recurrence has been observed. The use of lesion size index-guided ablation and isolation of the arrhythmogenic substrate in the caudal vena cava may minimise the risk of recurrence.

PV Based Single Stage Cascaded Seven Level Modular Multilevel Converter with ZSV Control for Grid Interfaced System

Objectives: Climatic perturbation and environmental factors affect solar power generation. When these solar panels are connected to the grid it causes power quality issues such as voltage harmonics, voltage distortion, etc. These problems are addressed in this paper using a distributed MPPT algorithm. Methods: Multilevel inverters have made remarkable contributions to renewable energy, high voltage, and other high-power applications. Hence, a single-stage Cascaded Seven-Level Modular Multilevel Converter (CSLMMC) is used to address the issues. Zero Sequence Voltage (ZSV) control is proposed for producing balanced power during varying irradiance conditions. The proposed method is simulated using MATLAB SIMULINK software. Partial shading is conquered by using distributed MPPT. Findings: The simulation of the proposed system is performed for a three-phase system. The three-phase Cascaded Modular Multilevel Converter is connected to the grid through two loads which are controlled by a Zero Sequence Voltage Controller. Power quality parameters such as current, harmonics, and power are analyzed for the proposed system. Novelty: THD analysis for a five-level cascaded H bridge converter and the proposed systems are compared and presented. Keywords: Photo voltaic, Cascaded seven-level modular multilevel converter, Zero sequence control, Maximum power point tracking, Voltage Source Converter

RuCo@C Hollow Nanoprisms Derived from ZIF-67 for Enhanced Hydrogen and Oxygen Evolution Reactions.

Zeolitic imidazolate frameworks (ZIFs) are commonly used to create complex hollow structures for energy applications. This study presents a simple method to produce a novel hollow nanoprism Co@C hierarchical composite from ZIF-67 through high-temperature treatment at 800 °C. This composite serves as a platform for Ru nanoparticle deposition, forming RuCo@C hollow nanoprism (RuCo@C HNP). As an electrocatalyst in 1 M KOH, RuCo@C HNP exhibits excellent hydrogen evolution reaction (HER) performance, with a low overpotential of 32 mV to reach 10 mA cm-2, a Tafel slope of 39.67 mV dec-1, a high turnover frequency (TOF) of 3.83 s-1 at ƞ200, and stable performance over 50 h. It also achieves a low ƞ10 of 266 mV for the oxygen evolution reaction (OER) with a Tafel slope of 45.22 mV dec-1. Density functional theory (DFT) calculations reveal that Ru doping in Ni/Co maintains a low water dissociation barrier, reduces the energy barrier for the OER rate-determining step, and creates active sites for H*, enhancing adsorption/desorption abilities. These results are attributed to the synergy between Co and Ru and the hollow prism structure's increased surface area. This method for synthesizing hollow structures using ZIF composites shows promise for applications in the energy sector.

Theoretical predictions of CO2, H2 and H2O adsorption mechanisms on M2C-MXene: Selectivity and potential application insights

M2C-MXenes, owing to their abundant adsorption sites, exhibit significant potential in CO2 capture, utilization, and storage (CCUS) and hydrogen energy applications, contributing to hydrogen utilization and global carbon reduction, and thus solving intractable energy and environmental problems. However, the extensive variety of M2C compounds poses challenges to the systematic evaluation of their applications in these fields. The exploration of the adsorption properties of M2Cs is a key fundamental aspect of these studies, and therefore, this study employs calculations across 456 adsorption systems to elucidate the adsorption mechanisms of 19 M2C compounds for small molecules (CO2, H2 and H2O). The results indicate that these M2C materials possess structural stability and metallic characteristics, with periodic variations in the d-band center aligning with trends in CO2 adsorption energy. Notably, molecular orientation impacts adsorption energy more significantly than adsorption sites, particularly for CO2, while M2C compounds primarily exhibit physical adsorption towards H2. Specifically, Sc2C preferentially adsorbs CO2 in atmospheric conditions, and shows chemical adsorption towards H2O, but exhibits negligible adsorption for H2; conversely, Cr2C demonstrates higher adsorption potential for H2. Both materials exhibit favorable thermodynamic stability, suggesting Sc2C is suitable for CCUS applications, while Cr2C holds promising prospects for hydrogen storage.

Enhanced Thermoelectric Performance of SnTe via Introducing Resonant Levels

SnTe has emerged as a non-toxic and environmentally friendly alternative to the high-performance thermoelectric material PbTe, attracting significant interest in sustainable energy applications. In our previous work, we successfully synthesized high-quality SnTe with reduced thermal conductivity under high-pressure conditions. Building on this, in this work, we introduced indium (In) doping to further decrease thermal conductivity under high pressure. By incorporating resonance doping into the SnTe matrix, we aimed to enhance the electrical transport properties while maintaining low thermal conductivity. This approach enhances the Seebeck coefficient to an impressive 153 μVK−1 at 735 K, marking a notable enhancement compared to undoped SnTe. Furthermore, we noted a substantial decrease in total thermal conductivity, dropping from 6.91 to 3.88 Wm−1K−1 at 325 K, primarily due to the reduction in electrical conductivity. The synergistic impact of decreased thermal conductivity and heightened Seebeck coefficient resulted in a notable improvement in the thermoelectric figure of merit (ZT) and average ZT, achieving approximately 0.5 and 0.22 in the doped samples, respectively. These advancements establish Sn1−xInxTe as a promising candidate to replace PbTe in thermoelectric applications, providing a safer and more environmentally sustainable option.

Azobenzene-Functionalized Semicrystalline Liquid Crystal Elastomer Springs for Underwater Soft Robotic Actuators.

As actuated devices become smaller and more complex, there is a need for smart materials and structures that directly function as complete mechanical units without an external power supply. The strategy uses light-powered, twisted, and coiled azobenzene-functionalized semicrystalline liquid crystal elastomer (AC-LCE) springs. This twisting and coiling, which has previously been used for only thermally, electrochemically, or absorption-powered muscles, maximizes uniaxial and radial actuation. The specially designed photochemical muscles can undergo about 60% tensile stroke and provide 15kJ m-3 of work capacity in response to light, thus providing about three times and two times higher performance, respectively, than previous azobenzene actuators. Since this actuation is photochemical, driven by ultraviolet (UV) light and reversed by visible light, isothermal actuation can occur in a range of environmental conditions, including underwater. In addition, photoisomerization of the AC-LCEs enables unique latch-like actuation, eliminating the need for continuous energy application to maintain the stroke. Also, as the light-powered muscles processed to be either homochiral or heterochiral, the direction of actuation can be reversed. The presented approach highlights the novel capabilities of photochemical actuator materials that can be manipulated in untethered, isothermal, and wet environmental conditions, thus suggesting various potential applications, including underwater soft robotics.

New stable rare earth Ti-based semiconductor pyrochlore oxides for low-cost energy applications

New stable rare earth Ti-based semiconductor pyrochlore oxides for low-cost energy applications

Numerical simulation of transient thermal stresses in medium- and high-temperature latent heat storage systems with different fins: Incorporation of experimental stress cracking

Latent heat storage systems play an essential role in energy applications by improving the utilization efficiency and increasing the system flexibility. In this study, a pilot-scale medium-to-high-temperature latent heat storage system was constructed, and experimental heat storage tests were conducted. The temperature distribution of the experimental system was verified through numerical simulations that coupled the physical fields of the fluids, heat transfer, and solid mechanics. Also, the changing dynamic behavior of the stresses in the heat storage process related to the experiments was carefully studied. It was discovered that there were stress concentrations where the heat exchanger tubes touched the casing, with the highest level being over 370.00 MPa. Experimental stress rupture of the shell occurred in the horizontally arranged heat-exchange tubes, whereas vertically arranged tubes significantly reduced the stress at the contact surfaces by 24.70 % according to simulations. Simulation studies on various influencing factors indicated a more significant impact of spiral fins on the system stress. Increasing the preheating temperature by 30 °C reduced stress on the front surface by 109.67 MPa; each 20 °C increase in heating temperature raised the stress by 223.30 MPa, whereas the effect of heat transfer fluid speed was minimal. Regarding the heat-exchange tube dimensions, increasing the height increased the tube body stress by 25.74 MPa, whereas increasing the thickness reduced the stress by 24.20 %. This study comprehensively analyzed the stress dynamics and mitigation strategies of the high-temperature latent heat storage system under various conditions, emphasizing the importance of heat-exchange tube orientation, temperature control, and fin design for optimizing system performance and durability.

Judicious combinations of gravity, magnetic, electrostatic separators and microwave heat energy on recovery of ilmenite from Humma lean grade beach placer deposit

Microwave heating is an eco-friendly and novel technique for sintering and heating minerals and materials as it has several advantages in terms of phase transformation, energy efficiency, enhancing speed, process simplicity, improved properties. Such heating provides the composite materials to absorb electromagnetic energy volumetrically and transform into heat and produces larger densities as compared to conventional heating. This study focuses on two main objectives: the recovery of ilmenite through a strategic combination of mineral processing equipment, including a spiral concentrator, followed by magnetic and electrostatic separation, and the enhancement of ilmenite concentrate using microwave heat energy on a cleaner magnetic product, followed by electrostatic separation. Continuous magnetic separation results indicate that among the dry high-intensity belt magnetic separator, box mag wet high-intensity magnetic separator and dry rare earth drum magnetic separators, the rare earth magnetic separator yielded the highest quality product. The application of microwave heat energy before the rare earth drum magnetic separator at 1.4 T, followed by high-tension separation, produced the best grade of ilmenite. The magnetic product obtained after microwave treatment contained 98.6% ilmenite, which was further upgraded to a 99.6% ilmenite concentrate through high-tension separation. Therefore, it is recommended that an effective combination of gravity separation, microwave heat energy, rare earth drum dry magnetic separation and high-tension separation be employed to achieve the highest grade of ilmenite concentrate.

Harnessing Quantum Materials for Enhanced Energy Efficiency and Storage: A Comprehensive Study of Electronic Properties and Performance Optimization

This research explores the exciting potential of various quantum materials to enhance energy efficiency and storage capabilities, filling in a crucial gap in our understanding of their electronic properties and interactions. A major hurdle in this field is the lack of empirical data on key factors such as conductivity, charge mobility, and thermal stability—elements that are vital for optimizing the performance of these materials in energy applications. Our study aims to blend experimental data with computational simulations to create a robust framework for modelling how quantum materials behave under different conditions. This comprehensive approach helps lay a solid foundation for their practical use in energy technologies. We focus on an array of fascinating quantum materials, including topological insulators, transition metal dichalcogenides, and superconductors. To investigate these materials, we employ advanced techniques like scanning tunnelling microscopy and spectroscopy, which allow us to delve deep into their unique properties. While pursuing this research, we do encounter challenges. Variations in sample quality, environmental factors during experimentation, and the complexities of theoretical modelling can affect the consistency of our results and the interpretation of our data. Despite these obstacles, our findings suggest that certain quantum materials hold remarkable potential for enhancing energy storage and conversion systems through improved charge mobility and thermal stability. In fact, some materials have demonstrated conductivity levels that surpass those of traditional options, hinting at transformative applications in energy technologies. These insights highlight the importance of continuing our exploration of quantum materials, positioning them as promising candidates for tackling today’s energy challenges and paving the way for advancements in sustainable energy solutions.

Agricultural Waste for Energy Storage, Conversion and Agricultural Applications

Agricultural waste residues (agro-waste) present a significant source of carbohydrates that are often underutilized despite their valuable properties. With increasing urbanization and limited non-renewable resources, the valorization of agro-waste is imperative. The global energy demand is on the rise, driven by factors such as population growth, industrialization, and a desire for enhanced living standards. Traditional energy sources, especially fossil fuels, have come under scrutiny for their environmental impact and limited availability. Consequently, there is an increasing focus on developing renewable and sustainable energy solutions, particularly through the use of agricultural waste. Agricultural waste—including crop residues, animal manure, and byproducts from food processing—represents a largely untapped resource for energy production. Converting this waste into valuable energy can help meet rising energy needs while offering environmental and economic advantages, such as mitigating waste disposal issues and creating additional income sources for the agricultural sector. Despite the significant potential of agricultural waste for energy storage and conversion, several challenges remain. These include issues related to logistics and transportation, the need for pretreatment, and concerns about economic feasibility. Future research should aim to enhance conversion technologies and better integrate agricultural waste into energy and agricultural systems. This review discusses various energy conversion technologies and applications of agricultural waste, including biofuels, biogas, and direct combustion, while exploring its role in energy storage through biochar. This review examines the composition and properties of agricultural waste, the various technologies available for energy conversion, and how agricultural waste can be utilized as a feedstock for biofuels, biogas, and direct combustion. It also investigates the integration of agricultural waste in energy storage solutions like biochar and explores other agricultural applications beyond energy production.

Multi-Criteria Decision-Making Approach for Optimal Energy Storage System Selection and Applications in Oman

This research aims to support the goals of Oman Vision 2040 by reducing the dependency on non-renewable energy resources and increasing the utilization of the national natural renewable energy resources. Selecting appropriate energy storage systems (ESSs) will play a key role in achieving this vision by enabling a greater integration of solar and other renewable energy. ESSs allow for solar power generated during daylight hours to be stored for use during peak demand periods. Additionally, the proposed framework provides guidance for large-scale ESS infrastructure planning and investments to support Oman’s renewable energy goals. As the global renewable energy market grows rapidly and Oman implements economic reforms, the ESS market is expected to flourish in Oman. In the near future, ESS is expected to contribute to lower electricity costs and enhance stability compared to traditional energy systems. While ESS technologies have been studied broadly, there is a lack of comprehensive analysis for optimal ESS selection tailored to Oman’s unique geographical, technical, and policy context. The main objective of this study is to provide a comprehensive evaluation of ESS options and identify the type(s) most suitable for integration with Oman’s national grid using a multi-criteria decision-making (MCDM) methodology. This study addresses this gap by applying the Hesitate Fuzzy Analytic Hierarchy Process (HF-AHP) and Hesitate Fuzzy VIKOR methods to assess alternative ESS technologies based on technical, economic, environmental, and social criteria specifically for Oman’s context. The analysis reveals pumped hydro energy storage (PHES) and compressed air energy storage (CAES) as the most appropriate solutions. The tailored selection framework aims to guide policy and infrastructure planning to determine investments for large-scale ESSs and provide a model for comprehensive ESS assessment in energy transition planning for countries with similar challenges.

Potentiostatic electrodeposition of copper, indium, and cadmium sulfides for CO2 electroreduction: A path toward sustainable hydrogen generation

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In2S3, and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In2S3, and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In2S3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In2S3, and CdS were found to have donor and acceptor concentrations (ND) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications.

Investigation of electronic, optical and thermoelectric properties in orthorhombic perovskite SmFeO3

In this work, we have investigated the electronic, optical, and thermoelectric properties of orthorhombic perovskite SmFeO3 using density functional and Boltzmann transport theories, for renewable energy applications. The modeling of the exact electron exchange-correlation has been carried out using both Generalized Gradient Approximation (GGA) and a functional modified with Hubbard interactions. The spin-polarized calculations show that SmFeO3 adopts a G-type antiferromagnetic configuration. The studied compound's electronic band structure and density of states analysis reveal its p-type semiconductor behavior. Furthermore, the optical properties such as real ε1(ω) and imaginary ε2(ω) components of the dielectric function as well as other conventional optical parameters, were investigated. The results show that SmFeO3 is a promising material for optoelectronic applications. The calculated transport properties including the Seebeck coefficient (S), the electrical conductivity (σ/τ), the electronic thermal conductivity (k0/τ) and the electronic figure of merit (ZTe) show significant results. The studied perovskite is also a potential candidate for thermoelectric applications, due to its high Seebeck coefficient, reaching 2388 μV/K, and the large electronic figure of merit which is close to 1 at room temperature. To improve the thermoelectric performance of SmFeO3 material, we have studied the effect of both p-type and n-type doping on its thermoelectric behavior at different temperature values.

Synthetic natural gas (SNG) production by biomass gasification with CO2 capture: Techno-economic and life cycle analysis (LCA)

The integration of renewables with CCUS technologies has the promising potential to deliver energy applications with overall negative CO2 emissions which would significantly contribute to the climate neutrality. Moreover, the renewable-based synthetic fuels are predicted to replace the conventional fossil fuels. The current work evaluates key techno-economic and environmental indicators for the SNG production from various renewable fuels (e.g., sawdust, residual wood, organic wastes, agricultural and urban wastes etc.) through gasification process fitted with decarbonization capability. The investigated plant capacity was set to 500 MWth SNG with 60 % CO2 capture rate of primary fuel (biomass). The overall concept was evaluated using various process engineering approaches e.g., reactor & process modelling and simulation, model validation, heat and power analysis, techno-economic assessment combined with detailed environmental impact by Life Cycle Analysis (LCA). The investigated design shows promising performance indicators such as high cumulative energy efficiency (69 %) and carbon conversion to SNG, almost zero plant specific CO2 emissions (3 kg/MWh) and overall negative carbon emissions (−457 kg/MWh) from the whole biomass chain. The SNG production cost is not yet fully competitive versus the EU natural gas prices (53 vs. 30–35 €/MWh) but it shows promising potential considering the trends of increasing fossil prices and CO2 emission tax.

Novel modular multilevel matrix converter topology for efficient high-voltage AC-AC power conversion

Introduction. This paper delves into the practical application of multilevel technology, particularly focusing on the capacitor-clamped converter as a promising solution for medium-to-high voltage power conversion, with specific emphasis on direct AC-AC switching conditions. Problem. The limitations of conventional single-cell matrix converters (MC) in efficiency and performance for medium-to-high voltage power conversion applications are well-recognized. Goal. The primary objective is to investigate the performance of the 3 phase modular multilevel matrix converter (3MC) with three flying capacitors (FCs) modeling. This investigation utilizes the Venturini method for gate pulse generation, aiming to compare the performance of the 3MC with standard converter designs. Methodology. To achieve the research goal, the Venturini method is adopted for generating gate pulses for the 3MC, representing a departure from conventional approaches. Detailed simulations employing MATLAB/Simulink are conducted to comprehensively evaluate the performance of the 3MC in comparison to conventional converter designs. Results. The simulation outcomes reveal a significant reduction of 73 % in total harmonic distortion (THD) achieved by the 3MC. This reduction in THD indicates improved robustness and suitability for medium-to-high voltage power conversion systems necessitating direct AC-AC conversion. These results highlight the efficacy of the 3MC in enhancing power conversion efficiency and overall performance. Originality. This paper contributes novel insights into the practical implementation of multilevel technology, particularly within the realm of capacitor-clamped converters. Furthermore, the utilization of the Venturini method for gate pulse generation in the 3MC represents an original approach to enhancing converter performance. Practical value. The research findings present significant advancements in multilevel transformer technology, offering valuable guidance for optimizing transformer design in various industrial and renewable energy applications. These contributions serve to enhance the development of reliable and efficient power systems, addressing critical needs in the energy sector. References 54, tables 3, figures 4.

Ionic liquid reinforced cellulose nanofiber with iron oxide electrocatalyst

Increased attention has been focused on the preparation of nanoarchitectures for applicability in energy, environmental and biological streams. However, concerns have been raised regarding environmental effects due to the harsh chemicals used in such preparations. To overcome this issue, the present study reports the use of a green solvent, 1-methyl-3-propyl-1H-imidazol-3-ium iodide or [Pmim]I, for the preparation of cellulose nanofiber-iron oxide (CNF-Fe2O3) composite. The as-prepared nanofiber composite is characterized with the aid of analytical tools such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy/energy dispersive X-ray spectroscopy (FE-SEM/EDX), and X-ray photoelectron spectroscopy (XPS). As a proof-of-concept demonstration, the resulting nanostructure is employed as an electrocatalyst and is compared with the bare CNFs, non-cellulose NFs and a standard RuO2 catalyst. The results indicate that the CNF-Fe2O3 composite achieves a standard current density (j) of 10 mA cm−2 at only 260 mV compared to 280, 290, and 370 mV for the standard RuO2, the bare CNFs, and non-cellulose nanofibers (NFs), respectively. These differences become more prominent at a high current density of 100 mA cm−2, where the CNF-Fe2O3 requires only 310 mV, while the CNFs, RuO2, and NFs consume 360, 370, and 550 mV, respectively.

Enhancing thermoelectric and radiation shielding performance of novel LaFe0.8Mn0.2Sb12 skutterudites for energy applications

We explore the structural, optoelectronic, and thermoelectric properties of LaFe0.8Mn0.2Sb12 skutterudites using first-principles computations and semi-classical Boltzmann Transport equations. These materials are classified as semiconductors exhibiting band gaps of 0.55 eV and 1.8 eV for spin-up and down polarizations. Valence band maxima (VBM) and conduction band minima (CBM) lie on the gamma points, indicating direct band gaps for both spin channels. The band structure, density of states, and optical characteristics reveal that the material is a semiconductor. The optical reflectivity and complex dielectric function were calculated for a wide range of photon radiation to understand these compounds' optical properties. The transport parameters were investigated using electrical conductivity, thermal conductivity, the Seebeck coefficient, the power factor, the heat capacity, and the figure of merit determined using the Boltztrap code. The LaFe0.8Mn0.2Sb12 has a Seebeck coefficient of 5.77×10−6 V/K (Up), whereas the down channel has a 4.2×10−6 V/K. The highest figure of merit is 0.99, and as a result, the theoretical findings provide a robust foundation for upcoming experimental research. In this study, utilize the Phy-X program to evaluate the radiation shielding capabilities of LaFe0.8Mn0.2Sb12, focusing on critical parameters like mass attenuation coefficients (γmac) and half-value layers (γhvl), essential for optimizing protection against hazardous ionizing radiation. Computational study of energy-renewable and thermoelectric properties enables experimenters to investigate fresh applications for predicting photovoltaic materials with atomic-level accuracy.

Exploring the impact of Anions, Alkyl group and confinement effect in ionic liquid @ UiO-66(Zr) MOF: A DFT study

Metal organic frameworks (MOFs) have emerged as a strong research material due to their exceptional porosity and tunable functional nature. MOF structures consist of metal nodes with organic linker, which can be functionalized depending on the required application. With the tunable properties, it has wide range of applications in energy, environmental and therapeutic approaches. Nevertheless there are several factors which can affect their performance such as lower affinity towards target molecules, chemical and thermal stability etc. To counter these issues several studies have been devoted on functionalizing the MOF. In this work, we have considered UiO-66 (University of Oslo-66) MOF because of its exceptional thermal and chemical stability with a series of versatile ionic liquids (ILs). The selected ILs are 1-ethyl-3-methylimidazolium ([C2MIm]+) and 1‑butyl‑3-methylimidazolium ([C4MIm]+) cations with various anions [X]−, where X = acetate (OAc), tetrafluroborate (BF4), dicyanamide (DCA), nitrite (NO2) and chloride (Cl) anions. These ILs have been impregnated in tetrahedral (∼10 Å) and octahedral (∼16 Å) pores of UiO-66 structure. First principle density functional theory (DFT) approach is used to study the structure, stability, spectral properties and charge transfer between IL/UiO-66 interfaces. Our calculations suggest that, IL does not affect the structure of UiO-66 surface. The anion and the alkyl group in the cations play a vital role in the stability of the complexes. Furthermore, confinement effect influence the stability of the complexes, irrespective nature of anion and cation. Electron density and charge transfer analyses reveal that anions have profound liking towards MOF because of having high electronegative atoms. Our study will help to understand the molecular level interaction between IL@MOF interface, and these composite can be utilized for the energy and environment related applications.

Comparative Analysis of an 8 – Stage Cockcroft Walton Voltage Multiplier and A Dickson Voltage Multiplier in The Context of Radio Frequency Energy Harvesting

Purpose: This study seeks to enhance voltage multipliers for Radio Frequency (RF) energy harvesting, with an emphasis on increasing the efficiency of harvested energy. This improvement is vital for sustainable energy applications and reducing environmental pollution caused by fossil fuels. Theoretical reference: RF energy harvesting technology is gaining recognition as a viable sustainable method for capturing ambient energy, with earlier research primarily focused on antenna and circuit design. Nonetheless, the effectiveness of energy harvesting is still constrained by inadequate power output. This study expands on prior research by directly comparing two commonly utilized voltage multipliers, the Cockcroft Walton and Dickson multipliers, in the context of RF energy harvesting. Method: The Cockcroft Walton and Dickson voltage multipliers were optimally designed using Multisim and their performance was analysed using MATLAB. The comparison was conducted at an input voltage of 1V within two frequency ranges: 85 MHz – 110 MHz (FM band) and 1.8 GHz – 3.0 GHz (4G band). Output voltages for both multipliers were recorded and compared across these frequency bands. Results and Conclusion: At an input voltage of 1V within the FM band (85 MHz – 110 MHz), the Dickson voltage multiplier outperformed the Cockcroft Walton multiplier, delivering an output voltage of 11.1V compared to 6.6V. However, in the 4G band (1.8 GHz – 3.0 GHz), the Cockcroft Walton multiplier was more effective, providing a maximum output voltage of 5.2V against Dickson's 4.1V. The study concludes that the Dickson multiplier is more suitable for harvesting RF energy from the FM band, while the Cockcroft Walton multiplier is better for 4G band energy harvesting. Implications of research: The findings suggest that different RF energy harvesting applications may benefit from distinct voltage multipliers, depending on the frequency band in question. This could guide the design of more efficient RF energy harvesting circuits in future technologies aimed at sustainable energy solutions. Originality/value: This study offers a direct comparison of two voltage multipliers under different RF frequency conditions, providing valuable insights into optimizing energy harvesting technologies for green energy applications. The results help advance the understanding of efficient circuit design for specific RF frequency bands, contributing to the development of more effective energy harvesting systems.