Johnson Matthey Technology Review - Current Issue

In power grid modernisation, optimal network use is essential to preserving acceptable voltage profiles, boosting voltage stability, reducing power losses, and strengthening system security and dependability. This can be accomplished by strategically placing reactive power compensation devices within transmission and distribution networks, such as capacitor banks, synchronous condensers, flexible alternating current transmission system (FACTS) devices and custom power devices. The optimal location and size of these devices are essential for effective investment, but previous research has mostly concentrated on a variety of methods for this goal, using different indices to evaluate power loss, voltage stability, voltage profile and line loadability. Despite these initiatives, there is still a lack of a thorough analysis of how current indices and methodologies are applied to all varieties of reactive power compensation devices. This paper offers a detailed literature review on the ideal placement and sizing of these devices, encompassing analytical, conventional and hybrid-based techniques. It discusses key objectives such as power loss reduction, voltage deviation (VD) mitigation, voltage stability enhancement and improvements in system reliability and security. Additionally, the paper examines the relevance of reactive power for stakeholders, including transmission system operators (TSOs), distribution system operators (DSOs) and power generating companies, and explores the mathematical modelling of optimal reactive power dispatch (ORPD), considering the impact of renewable energy sources (RESs) and the role of FACTS devices.

The inherent variability and the sporadic and unpredictable nature of solar irradiance limit the efficiency of photovoltaic (PV) arrays in consistently achieving maximum power output. This paper addresses the technical challenge of enhancing power extraction efficiency from PV systems by implementing and conducting a comparative study of various maximum power point tracking (MPPT) algorithms. The various algorithms which are considered for analysis purpose are perturb and observe algorithm (P&O), incremental conductance algorithm (INC) and fuzzy logic-based algorithm (FLC). The objective is to identify the most effective algorithm to maintain PV array operation near its maximum power point (MPP) under dynamic environmental conditions. The methodology involves configuring a direct current (DC) DC-DC converter with precise duty cycle adjustments to optimise energy conversion and transfer. Additionally, the extracted energy is directed to a battery or energy storage unit via a secondary converter. The system is simulated in MATLAB^® to test and compare the performance of different MPPT algorithms. This facilitates the determination of which algorithm most efficiently optimises power extraction from the PV system.

By combining formulae known from the literature that relate thermoelectric parameters, the expression n ≅ 1.13·10¹⁹e^Sr–2/rH(e^Sr–2–0.17) is obtained. That is, the concentration of charge carriers can be determined using the Hall resistance (rH) and reduced Seebeck coefficient. Since these two parameters are calculated using the Seebeck coefficient (S), this coefficient is sufficient to determine the concentration. To demonstrate the use of the obtained new formula, experimental data on silicon-germanium thermoelectric are discussed.

This two-part review delves into the production of sustainable aviation fuels (SAF) derived from biomass and residual wastes through pyrolysis. Part I addresses the challenges associated with the pyrolysis of wastes and provides an overview of both conventional and emerging pyrolysis technologies, the diverse forms of biomass and its significant economic benefits on a global scale. Approximately half of the global population relies on biomass as their primary energy source. Three types of biomass energy are biogas, bio-liquid and bio-solid. In the domains of transportation and energy, it can serve as a substitute for fossil fuels. The primary focus of this study is to examine the data, explore the potential of biomass and analyse the mechanisms of pyrolysis carried out using various processes, technologies (such as pyrolysis speed and temperature) and different types of reactors to produce bio-oil.

Part II of this review examines the current state and forthcoming obstacles of the pyrolysis process in addition to the diverse array of pyrolysis byproducts. Based on this research, it can be inferred that the characteristics of pyrolysis products are influenced by the diversity of materials utilised. Furthermore, pyrolysis products, such as bio-oil, have the potential to make a lucrative contribution to the expanding economy. To overcome future problems, further exploration is ultimately necessary. The primary factors of significance in pyrolysis technology are government subsidies and scientific advancements. The discussion emphasises the significant barriers posed by the energy efficiency and capital costs involved in converting biomass and residual wastes into aviation fuels, hindering widespread adoption. To meet the aviation industry’s greenhouse gas reduction targets by 2050, there is a pressing need for further advancements in technology development, highlighting the critical role of advanced technologies in overcoming these barriers.

Nanoparticles (NPs) have many applications, such as in health and agriculture. One of these essential NPs is silver, which can be applied for drug delivery like encapsulation. Silver NPs (AgNPs) have excellent antibacterial activity. In addition, silver synthesis can be explored by electrochemical approaches on bacterium after exposure to silver. The synthesis of NPs can be achieved by biogenic synthesis, for instance, Morganella psychrotolerans, silver-resistant psychrophilic bacteria. Morganella psychrotolerans is a bacterium with the same character as Morganella morganii for synthesising AgNPs. The ability of Morganella morganii was expressed due to its specificity to maintain high deliberation of silver through the cell synthesis of rounded AgNPs and its ability to grow at lower temperatures (psychros: cold) in the range of 0–30°C. Anisotropy of AgNPs can be attained by controlling the bacteria growth kinetics. This synthesis system can be employed in a green biosynthetic approach to achieve shape control of NPs in an environmentally friendly, scalable and economical process. This review discusses Morganella psychrotolerans for controlling shape and biogenic synthesis with related aspects such as the synthesis mechanism, the influencing factors like shape and size, the application method and its development.

The increase in population and need for energy in the world’s fastest developing economies like India make it critical to increase the supply of energy and augment its utilisation. According to most energy projections, the expected future global demand patterns of energy are not sustainable. Thus, India will soon run out of its non-renewable energy sources. As per the study analysis, India receives 657.4 MW of solar radiation which when converted to power can be utilised to attain the energy demand of India. Solar hotspots represent geographical areas that receive abundant solar energy and offer significant prospects for commercial energy generation. Our study reveals that approximately 58% of India’s geological zones qualify as sun-based hotspots. Furthermore, we propose an economically viable setup of solar plants based on the identified hotspots. To analyse these solar hotspots in India, we have employed a density-based three-dimensional (3D) clustering approach. In our research, we have substantially enhanced the efficiency of the 3D density-based spatial clustering of applications with noise (DBSCAN) spatial clustering method by incorporating K-dimensional (KD) trees and spatial indexing for 3D data. We conducted a comparative analysis between two techniques: 3D DBSCAN using the Euclidean distance as the distance metric and 3D DBSCAN spatial clustering with KD trees as the distance function, aiming to optimise nearest neighbour searches. Our analysis demonstrates that, particularly when evaluating solar hotspots, utilising 3D DBSCAN spatial clustering with KD trees yields more accurate results, especially when considering statistical parameters like the Silhouette score and Dunn index.

Under the effect of magneto-hydrodynamic (MHD) conditions including thermophoresis, gyrotactic microbes, Brownian motion and nanofluid particles, this work investigates the steady flow of a three-dimensional, viscous, electrically conducting, non-Newtonian Maxwell fluid along a bidirectional stretching sheet composed of porous material. Simplified to non-linear ordinary differential equations (ODEs), the governing equations are numerically solved using MATLAB^® bvp4c. While their effects on the local Sherwood number, frictional drag coefficient, local Nusselt number and local microbe count are given in tabular form, their effects on temperature, velocity, microorganisms and concentration are graphically illustrated. Results of the research show that improving bioconvection Lewis and Peclet numbers as well as microbe differential parameter reduce the profiles of microorganisms.

The Ćuk converter is extensively utilised across various applications for its capability to handle a wide range of input voltages and efficiently perform both voltage step-up and step-down conversions. However, the presence of parasitic elements, such as inductor winding resistance, capacitor equivalent series resistance (ESR) and losses in switches and diodes, significantly impacts the converter’s performance, stability and efficiency. This paper addresses these challenges by analysing the effects of non-idealities in Ćuk converters operated under closed-loop voltage mode control. A detailed mathematical model of a 12 V to 24 V Ćuk converter is developed to evaluate the influence of parasitic elements and their interactions within the control system. This model provides valuable insights into the complexities introduced by these non-idealities and serves as a foundation for designing more resilient control strategies. To ensure output voltage stability and improved dynamic performance, a proportional integral derivative (PID) controller is employed with parameters optimised using the Ziegler-Nichols tuning method. The proposed control strategy is validated through MATLAB^® simulations, showcasing its effectiveness in countering the adverse effects of parasitics. The results indicate a stable operation with a steady-state error of less than 1%, a peak overshoot of 6.31%, a rise time of 6.21 ms and a settling time of 37.4 ms. This work contributes to enhancing closed-loop voltage mode control strategies for non-ideal Ćuk converters, offering practical solutions to improve their reliability and efficiency in real-world applications.

Currently, the traditional hydrodesulfurisation (HDS) process is extensively utilised in the oil refining industry to remove sulfur compounds from petroleum fractions which have environmental and health impacts in addition to affecting product quality. The HDS process needs high pressure and temperature, uses costly hydrogen gas and has low activity towards extraction of thiophene and its derivatives. Alternative desulfurisation processes like catalytic oxidative desulfurisation (ODS) are possible approaches because of mild process conditions, no need for hydrogen and efficiency in removing thiophene and its derivatives. ODS is developed using various types of catalyst, oxidants and designs of reactors under different operating conditions. In continuation with developing more workable and economical parameters in ODS technology, different types of reactors are considered as alternatives to the traditional batch reactors. This three-part work investigates the most recent developments in reactors for ODS processes and reviews the advantages, limitations and future potential of each reactor.