bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy and Exergy Analysis on a Blast Furnace Gas-Driven Cascade Power Cycle
Authors: Chen Hao , Wang Yiming , Yan Linbo , Wang Ziliang , He Boshu , Fang Baizeng
Published: November 2022

Blast furnace gas is the major combustible by-product produced in the steel industry, where iron ore is reduced by coke into iron. Direct combustion of blast furnace gas after simple treatment for power generation is a common utilization method nowadays. However, this method suffers from low efficiency and high carbon intensity. The use of gas-steam combined cycle is an excellent method to improve the efficiency of blast furnace gas for power generation. However, there is a problem of insufficient utilization of low product heat, and the addition of CCS system can further reduce the power efficiency. To solve these issues, a new blast furnace gas power generation system with a Brayton cycle with supercritical CO2 and a Rankine cycle with transcritical CO2 is proposed in this work. The new system is then thermodynamically simulated by Aspen Plus, after the sub-modules are validated. The effects of molar ratio of steam to carbon, selexol/CO2 mass ratio, compression ratio, turbine import temperature and turbine inlet pressure on the system are investigated. A comparison is also performed between the new combined cycle system and the traditional combined cycle power generation system. The results show that in the new power generation system, net power efficiency of 53.29%, carbon capture efficiency of 95.78% and sulfur capture rate of 94.46% can be achieved, which is significantly better than the performance of the conventional combined cycle.
Deep Reinforcement Learning for the Optimal Angle Control of Tracking Bifacial Photovoltaic Systems
Authors: Tsuchida Shuto , Nonaka Hirofumi , Yamada Noboru
Published: November 2022

An optimal tilt-angle control based on artificial intelligence (AI control) for tracking bifacial photovoltaic (BPV) systems is developed in this study, and its effectiveness and characteristics are examined by simulating a virtual system over five years. Using deep reinforcement learning (deep RL), the algorithm autonomously learns the control strategy in real time from when the system starts to operate. Even with limited deep RL input variables, such as global horizontal irradiance, time, tilt angle, and power, the proposed AI control successfully learns and achieves a 4.0–9.2% higher electrical-energy yield in high-albedo cases (0.5 and 0.8) as compared to traditional sun-tracking control; however, the energy yield of AI control is slightly lower in low-albedo cases (0.2). AI control also demonstrates a superior performance when there are seasonal changes in albedo. Moreover, AI control is robust against long-term system degradation by manipulating the database used for reward setting.
The Role of Micro Gas Turbines in Energy Transition
Authors: Banihabib Reyhaneh , Assadi Mohsen
Published: November 2022

In the progressively rising decentralized energy market, micro gas turbines (MGT) are seen with great potential owing to their low emissions, fuel flexibility, and low maintenance. The current transformation in the landscape of electricity supply with an increasing share of fluctuant renewable energy resources and increasing complexity requires a reliable and energy-efficient power generation source to support the grid. In this scenario, small-scale power plants that are constructed based on micro gas turbines with up to 250 kW power range can play a substantial role in meeting the challenges of the modern electricity grid. Micro gas turbines provide a reliable and cost-effective power source with a quick load-following ability which can respond to demand peaks and compensate for intermittent renewable sources when they are not available. MGT units can work as a system together with renewables, or function as a stand-alone unit in off-grid operations. The features of micro gas turbines are compatible with the energy transition that is the carbon-free modern energy grid. The technology underlying MGTs offer hybridization with renewable energy sources, flexibility in operations and type of fuel, and promising low emission solutions that align with environmental concerns. However, there is a continuous need to improve energy efficiency with a pressing urge for reducing emissions. This paper provides a review of micro gas turbines’ characteristics which promote their role in future power and heat generation systems. A brief overview of the challenges to improving operational flexibility, reliability, and availability of MGTs while maintaining low environmental impact and lowering the costs is presented. A model for an active monitoring and control system of the micro gas turbines is proposed which could improve the reliability of MGT operation in the grid by means of AI methods.
Hard Carbon Reprising Porous Morphology Derived from Coconut Sheath for Sodium-Ion Battery
Authors: Thenappan Meenatchi , Rengapillai Subadevi , Marimuthu Sivakumar
Published: November 2022

Seeking effective energy technology has become a herculean task in today’s world. Sodium-ion batteries play a vital role in the present energy tech market due to their entrancing electrochemical properties and this work is a breakthrough for developing sodium-ion batteries. As per recent reports, the preparation of anode materials seems to be very tedious in the realm of sodium-ion batteries. To remedy these issues, this work enlightens the preparation of hard carbon (HC) derived from coconut sheath (CS) by a pyrolysis process with different activating agents (KOH, NaOH, ZnCl2) and employed as an anode material for Sodium-ion batteries (SIBs). The prepared anode material was characterized for its thermal, structural, functional, morphological, and electrochemical properties. Additionally, the surface area and pore diameter of the as-prepared anode material was studied by nitrogen adsorption and desorption isotherm methods. The coconut sheath-derived hard carbon (CSHC) anode material delivered an initial charge capacity of 141 mAh g−1, 153 mAh g−1, and 162 mAh g−1 at a 1 C rate with a coulombic efficiency over 98.8%, 99.3%, and 99.5%, even after 100 cycles, respectively.
Research on an Off-Chip Microvalve for Pneumatic Control in Microfluidic Chips
Authors: Liu Xuling , Zuo Wensi , Song Huafeng , Shang Tingdong , Dong Haiwei , Wang Liangwen , Shao Jinggan , Li Songjing
Published: November 2022

A compact, rapid, and portable off-chip pneumatic control valve is significant for the miniaturization and integration of external pneumatic systems for microfluidic chips. In this work, an off-chip microvalve with a high-speed electromagnetic switch actuator and a polydimethylsiloxane (PDMS) material valve body has been designed to be easily encapsulated, simulated using MATLAB/Simulink software, and tested in a micromixer. Multi-physical coupling mathematical models are developed based on the elastic deformation force of the valve membrane, the driving force of the valve core, and the fluid force in the microchannel. Two single microvalves are used to form a three-way microvalve, which can control the air pressure in a pneumatic microchannel on the microfluidic chip. The relationship between the flow–duty cycle, the flow–pressure difference of the single electromagnetic microvalve, and the load pressure of the three-way microvalve is simulated and analyzed. Sample mixing performance controlled by the proposed off-chip three-way microvalve was tested to evaluate the pneumatic control capability, and the results show that the undertaking can fully satisfy the needs of a pneumatic microfluidic chip for most applications.
Enhanced Retention and Synergistic Plugging Effect of Multi-Complexed Gel on Water-Swellable Rubber
Authors: Li Tong , Yang Wenwu , Wu Jiajun , Xing Peidong , Xu Qian , Liu Hegao , Cao Guangsheng
Published: November 2022

For the management of fractured large pores in high-water-bearing reservoirs, the general approach is to use transfer dissection and sealing. Conventional regulators have a limited regulating radius and can only produce blocking in the near-well zone, which is not ideal. Deep dissection technology can expand the radius of action and substantially improve the blocking effect. The existing deep-dissection agent system has problems such as high cost and poor effect, which affect its large-scale application. In this paper, to address these problems, a gel-type dissection modifier cross-linking agent was synthesized and optimized in the laboratory using low-concentration polymer, and the factors affecting the final gel formation effect were experimentally studied. The final polymer concentration was chosen to be 1500 mg/L~3000 mg/L, the poly-crossing ratio was 30:1, the pH was controlled at 7–9, and the temperature was controlled at 30–60 °C; the rubber was formed with good shear resistance and thermal stability, and had good adaptability to the high-mineralization environment. The optimal injection concentration of water-expanded rubber particles for this system was confirmed to be 3000 mg/L. Cryo-electron microscopy was used to observe the morphology of polymer gel formation and the adhesion of nucleated water-expanded particles to the gel, to clarify the mechanism of enhanced retention and sealing of nucleated water-expanded rubber particles by the multiple complex gel system, and finally to verify the sealing performance of the composite sealing system and determine the use effect by indoor simulation experiments with a two-dimensional flat plate model. This study is of great significance for the efficient development of high-water-bearing late reservoirs and further improvement of crude oil recovery.
An Intelligent Recognition Method for Low-Grade Fault Based on Attention Mechanism and Encoder–Decoder Network Structure
Authors: Zhang Yujie , Wang Dongdong , Ding Renwei , Yang Jing , Zhao Lihong , Zhao Shuo , Cai Minghao , Han Tianjiao
Published: November 2022

Low-grade faults play an important role in controlling oil and gas accumulations, but their fault throw is small and difficult to identify. Traditional low-grade fault recognition methods are time-consuming and inaccurate. Therefore, this study proposes a combination of a simulated low-grade fault sample set and a self-constructed convolutional neural network to recognize low-grade faults. We used Wu’s method to generate 500 pairs of low-grade fault samples to provide the data for deep learning. By combining the attention mechanism with UNet, an SE-UNet with efficient allocation of limited attention resources was constructed, which can select the features that are more critical to the current task objective from ample feature information, thus improving the expression ability of the network. The network model is applied to real data, and the results show that the SE-UNet model has better generalization ability and can better recognize low-grade and more continuous faults. Compared with the original UNet model, the SE-UNet model is more accurate and has more advantages in recognizing low-grade faults.
A Selective Review on Recent Advancements in Long, Short and Ultra-Short-Term Wind Power Prediction
Authors: Sawant Manisha , Patil Rupali , Shikhare Tanmay , Nagle Shreyas , Chavan Sakshi , Negi Shivang , Bokde Neeraj Dhanraj
Published: November 2022

With large penetration of wind power into power grids, the accurate prediction of wind power generation is becoming extremely important. Planning, scheduling, maintenance, trading and smooth operations all depend on the accuracy of the prediction. However due to the highly non-stationary and chaotic behaviour of wind, accurate forecasting of wind power for different intervals of time becomes more challenging. Forecasting of wind power generation over different time spans is essential for different applications of wind energy. Recent development in this research field displays a wide spectrum of wind power prediction methods covering different prediction horizons. A detailed review of recent research achievements, performance, and information about possible future scope is presented in this article. This paper systematically reviews long term, short term and ultra short term wind power prediction methods. Each category of forecasting methods is further classified into four subclasses and a comparative analysis is presented. This study also provides discussions of recent development trends, performance analysis and future recommendations.
Stochastic Wind Power Generation Planning in Liberalised Electricity Markets within a Heterogeneous Landscape
Authors: Sund Lennard , Talari Saber , Ketter Wolfgang
Published: November 2022

Spatially separated locations may differ greatly with respect to their electricity demand, available space, and local weather conditions. Thus, the regions that are best suited to operating wind turbines are often not those where electricity is demanded the most. Optimally, renewable generation facilities are constructed where the maximum generation can be expected. With transmission lines limited in capacity though, it might be economically rational to install renewable power sources in geographically less favourable locations. In this paper, a stochastic bilevel optimisation is developed as a mixed-integer linear programme to find the socially optimal investment decisions for generation expansion in a multi-node system with transmission constraints under an emissions reduction policy. The geographic heterogeneity is captured by using differently skewed distributions as a basis for scenario generation for wind speeds as well as different opportunities to install generation facilities at each node. The results reinforce that binding transmission constraints can greatly decrease total economic and emissions efficiency, implying additional incentives to enhance transmission capacity between the optimal supplier locations and large demand centres.
Characterization of Aerodynamics of Small Wind Turbine Blade for Enhanced Performance and Low Cost of Energy
Authors: Kelele Hailay , Frøyd Lars , Kahsay Mulu , Nielsen Torbjørn
Published: November 2022

During a turbine’s lifetime, minimizing the cost of power production should be the primary aim in addition to attaining high technical efficiency. Thus, this paper was aimed at enhancing the aerodynamic efficiency of a site-specific small wind turbine considering the cost of energy as one of the design parameters. The wind distribution of a specific site was employed to characterize the wind using the Weibull distribution method. The aerodynamics of a typical 5 kW wind turbine blade were investigated by implementing a blade element method (BEM) using a MATLAB code that applied the advancements and improvements with different modifications and which was validated by engaging computational fluid dynamics (Ansys-Fluent). The optimal pitch angle was then employed to further promote the performance characteristics of the blade. The cost of energy was reformulated in terms of rated power considering a cost variation of the main components that deviates with the rated power. Accordingly, the performance parameters were investigated against a varying rated power and the relative cost of energy, achieving a maximum power coefficient of 55.37% at a lower cost of energy. Moreover, annual energy production of approximately 18 MWh with a corresponding capacity factor of approximately 41% was achieved at a lower cost of energy. These findings demonstrate that the selected modelling, analysis procedures, and modifications enhance the aerodynamic performance characteristics and lower the cost of energy of the small wind turbine blade, which promotes the affordability and energy harnessing capability of small wind turbines.
Hysteresis Based Quasi Fixed Frequency Current Control of Single Phase Full Bridge Grid Integrated Voltage Source Inverter
Authors: Syamala Lakshmi , Sankar Deepa , Makkar Suhara Ekkarakkudy , Jos Bos Mathew , Kallarackal Mathew
Published: November 2022

The traditional Fixed Band Hysteresis Current Control (FB-HCC) though being widely used for the current control of grid integrated voltage source inverter (GI-VSI), has the drawback of variable switching frequency. To overcome this drawback, Complex Programmable Logic Device (CPLD) based switching scheme is proposed in this paper. The proposed method calls for a single reference wave and the control concept is to terminate the rising and falling inductor current (iL) either by the comparator or by the CPLD, based on the nature of its slope. Termination of the iL with steeper slope by the comparator ensures lower current ripple, whereas the CPLD ensures constant switching frequency (fsw). However, the iL obtained with the proposed logic has a DC offset, which is corrected by modifying the reference. The basic concept, switching logic, and reference correction are thoroughly detailed. MATLAB/Simulink results are included to verify the proposed concept. The constant frequency operation of the proposed method is also validated in a 2 kW, 230 V, 50 Hz GI-VSI prototype.
Possible Ways of Extending the Biogas Plants Lifespan after the Feed-In Tariff Expiration
Authors: Benato Alberto , D’Alpaos Chiara , Macor Alarico
Published: November 2022

Energy production from biogas can play a pivotal role in many European countries, and specifically in Italy, for three main reasons: (i) fossil fuels are scarce, (ii) imports cover large shares of internal demand, and (iii) electricity and heat production from biogas is already a consolidated business. Nonetheless, in Italy, current legislation and incentive policies on electricity generation from biogas are causing a stagnation of the entire sector, which may lead to the shutting down of many in-operation plants in the years 2027–2028 and the consequent loss of 573 MWel over a total of 1400 MWel. This work aims to investigate the potential of revamping biogas power plants in prolonging operation until the end of the plants’ useful life, regardless of the implementation of a new government’s incentive schemes. Based on the time-series analysis of electricity prices in Italy and a case study representative of the vast set of in-operation power plants, our findings show that 700 plants will likely shut down between 2027 and 2028 unless the government adequately rewards electricity produced and fed into the grid via incentive schemes. In detail, our results show that the investment to revamp the plant exhibits a highly negative Net Present Value.
Strategies for the Modelisation of Electric Vehicle Energy Consumption: A Review
Authors: Di Martino Andrea , Miraftabzadeh Seyed Mahdi , Longo Michela
Published: November 2022

The continuous technical improvements involving electric motors, battery packs, and general powertrain equipment make it strictly necessary to predict or evaluate the energy consumption of electric vehicles (EVs) with reasonable accuracy. The significant improvements in computing power in the last decades have allowed the implementation of various simulation scenarios and the development of strategies for vehicle modelling, thus estimating energy consumption with higher accuracy. This paper gives a general overview of the strategies adopted to model EVs for evaluating or predicting energy consumption. The need to develop such solutions is due to the basis of each analysis, as well as the type of results that must be produced and delivered. This last point strongly influences the whole set-up process of the analysis, from the available and collected dataset to the choice of the algorithm itself.
Operation of Power-to-X-Related Processes Based on Advanced Data-Driven Methods: A Comprehensive Review
Authors: Ullah Mehar , Gutierrez-Rojas Daniel , Inkeri Eero , Tynjälä Tero , Nardelli Pedro H. J.
Published: November 2022

This study is a systematic analysis of selected research articles about power-to-X (P2X)-related processes. The relevance of this resides in the fact that most of the world’s energy is produced using fossil fuels, which has led to a huge amount of greenhouse gas emissions that are the source of global warming. One of the most supported actions against such a phenomenon is to employ renewable energy resources, some of which are intermittent, such as solar and wind. This brings the need for large-scale, longer-period energy storage solutions. In this sense, the P2X process chain could play this role: renewable energy can be converted into storable hydrogen, chemicals, and fuels via electrolysis and subsequent synthesis with CO2. The main contribution of this study is to provide a systematic articulation of advanced data-driven methods and latest technologies such as the Internet of Things (IoT), big data analytics, and machine learning for the efficient operation of P2X-related processes. We summarize our findings into different working architectures and illustrate them with a numerical result that employs a machine learning model using historic data to define operational parameters for a given P2X process.
Effect of Airflow Non-Uniformities on the Thermal Performance of Water–Air Heat Exchangers—Experimental Study and Analysis
Authors: Khaled Mahmoud , Mortada Mostafa , Faraj Jalal , Chahine Khaled , Lemenand Thierry , Ramadan Haitham S.
Published: November 2022

The thermal performance of fin-and-tube heat exchangers (HX) is a crucial aspect in a multitude of applications and fields; several design and operational parameters influence this performance. This study focuses on the issue of flow maldistribution and its effect on the HX thermal performance. For this purpose, an experimental setup is designed and implemented to emulate the conditions under which an automotive heat exchanger operates in regard to the non-uniform upstream airflow velocity distribution over the HX surface. The setup allows obtaining various configurations of airflow velocity non-uniformity of some desired mean velocity and standard deviation. The experimental results reveal that a higher degree of non-uniformity (higher standard deviation of the velocity distribution) causes an increased deterioration of the HX thermal performance. For example, at a water flowrate of 200 L/h and a mean airflow velocity of 2 m/s, increasing the standard deviation from 0 to 2 m/s (i.e., moving from the lowest to highest degrees of non-uniformity) causes a total deterioration of 27% in the performance (3.78 to 2.75 kW, respectively), which can also be observed in the increased level of outlet water temperature (53.8 to 58.2 °C, respectively). The obtained results confirm the numerical results reported in the literature.
Computational Fluid Dynamics of Influence of Process Parameters and the Geometry of Catalyst Wires on the Ammonia Oxidation Process and Degradation of the Catalyst Gauze
Authors: Tyrański Mariusz , Pasik Izabela , Bujalski Jakub Michał , Orciuch Wojciech , Makowski Łukasz
Published: November 2022

The ammonia oxidation reaction on solid platinum–rhodium gauze is a critical step in nitric acid production. As the global demand for food and fertilisers keeps steadily growing, this remains an essential reaction in the chemical industry. However, harsh conditions inside ammonia burners lead to the degradation of catalytic meshes, severely hindering this process. This manuscript is focused on two issues. The first is the influence of catalyst gauze geometry and process parameters on the efficiency of ammonia oxidation on platinum–rhodium gauze. The second investigated problem is the influence of geometry on catalyst fibre degradation and the movement and deposition of entrained platinum particles. Computational Fluid Dynamics was utilised in this work for calculations. Different catalyst gauze geometries were chosen to examine the relationship between wire geometry and heat and mass transfer by analysing temperature and flow fields. Significantly, the analysis of the temperature gradient on the catalyst surface allowed us to estimate the spots of highest wire degradation and to track lifted platinum particles. The Discrete Phase Model was used to calculate entrained platinum particle trajectories and their deposition’s localisation and efficiency.
Hydrogen Storage Assessment in Depleted Oil Reservoir and Saline Aquifer
Authors: Delshad Mojdeh , Umurzakov Yelnur , Sepehrnoori Kamy , Eichhubl Peter , Batista Fernandes Bruno Ramon
Published: November 2022

Hydrogen (H2) is an attractive energy carrier to move, store, and deliver energy in a form that can be easily used. Field proven technology for underground hydrogen storage (UHS) is essential for a successful hydrogen economy. Options for this are manmade caverns, salt domes/caverns, saline aquifers, and depleted oil/gas fields, where large quantities of gaseous hydrogen have been stored in caverns for many years. The key requirements intrinsic of a porous rock formation for seasonal storage of hydrogen are: adequate capacity, ability to contain H2, capability to inject/extract high volumes of H2, and a reliable caprock to prevent leakage. We have carefully evaluated a commercial non-isothermal compositional gas reservoir simulator and its suitability for hydrogen storage and withdrawal from saline aquifers and depleted oil/gas reservoirs. We have successfully calibrated the gas equation of state model against published laboratory H2 density and viscosity data as a function of pressure and temperature. Comparisons between the H2, natural gas and CO2 storage in real field models were also performed. Our numerical models demonstrated more lateral spread of the H2 when compared to CO2 and natural gas with a need for special containment in H2 projects. It was also observed that the experience with CO2 and natural gas storage cannot be simply replicated with H2.
Effect of Stator Blades on the Startup Dynamics of a Vertical Axis Wind Turbine
Authors: Asim Taimoor , Singh Dharminder , Siddiqui M. Salman , McGlinchey Don
Published: November 2022

Vertical Axis Wind Turbines (VAWTs) are omni-directional, low-cost, low-efficiency wind power extractors. A conventional drag-based VAWT consists of multiple thin rotor blades with a typical peak Tip Speed Ratio (λ) of < 1. Their lower cut-in speed and maintenance cost make them ideal for power generation in urban environments. Numerous studies have been carried out analysing steady operation of VAWTs and quantifying their performance characteristics, however, minimal attention has been paid to their start-up dynamics. There are a few recent studies in which start-up dynamics of lift-based VAWTs have been analysed but such studies for drag-based VAWTs are severely limited. In this study, start-up dynamics of a conventional multi-blade drag-based VAWT have been numerically investigated using a time-dependant Computational Fluid Dynamics (CFD) solver. In order to enhance the start-up characteristics of the drag-based VAWT, a stator has been integrated in the design assembly. The numerical results obtained in this study indicate that an appropriately designed stator can significantly enhance the start-up of a VAWT by directing the flow towards the rotor blades, leading to higher rotational velocity (ω) and λ. With the addition of a stator, the flow fields downstream the VAWT becomes more uniform.
Resilience Maximization in Electrical Power Systems through Switching of Power Transmission Lines
Authors: Pilatásig Jaime , Carrión Diego , Jaramillo Manuel
Published: November 2022

This research aims to maximize the resilience of an electrical power system after an N−1 contingency, and this objective is achieved by switching the transmission lines connection using a heuristic that integrates optimal dc power flows (DCOPF), optimal transmission switching (OTS) and contingencies analysis. This paper’s methodology proposes to identify the order of re-entry of the elements that go out of the operation of an electrical power system after a contingency, for which DCOPF is used to determine the operating conditions accompanied by OTS that seeks to identify the maximum number of lines that can be disconnected seeking the most negligible impact on the contingency index J. The model allows each possible line-switching scenario to be analyzed and the one with the lowest value of J is chosen as the option to reconnect, this process is repeated until the entire power system is fully operational. As study cases, the IEEE 14, 30 and 39 bus bars were selected, in which the proposed methodology was applied and when the OTS was executed, the systems improved after the contingency; furthermore, when an adequate connection order of the disconnected lines is determined, the systems are significantly improved, therefore, the resilience of power systems is maximized, guaranteeing stable, reliable and safe behavior within operating parameters.
Arrangement of LEDs and Their Impact on Thermal Operating Conditions in High-Power Luminaires
Authors: Różowicz Antoni , Wachta Henryk , Baran Krzysztof , Leśko Marcin , Różowicz Sebastian
Published: November 2022

Solid-state light sources are currently the fastest-growing group of light sources, replacing the previously used discharge and incandescent light sources. Thermal operating conditions of LEDs (Light Emitting Diode) play an important role in t maintaining long service life and constancy of luminous-electrical parameters. In the field of illumination, the service life parameter of light sources is important for the costs of maintenance of the illumination system, while the maintenance of the value of certain light parameters over time, such as luminous flux, color temperature and color rendering index, is related to the aesthetic effect of the illumination. In addition, limiting the junction temperature of solid-state light sources is particularly important in high-power luminaires dedicated to flood illumination. One of the elements shaping the thermal operating conditions of multi-source LED luminaires is the number of luminaires used, their arrangement, and the distance between LEDs installed on the MCPCB (Metal Core Printed Circuit Board) substrate. This article presents the results of simulation studies, realized using CFD (Computational Fluid Dynamics) software, where the temperature distribution and the junction temperature of the LED panel were determined for different configurations and distances between the LEDs. The results obtained were analyzed and conclusions were drawn based on them. Thermal tests performed and presented in the article cover scientific issues related to shaping the temperature distribution of the LED panel. They make it possible to determine the influence of thermal couplings between the sources, related to their number, distance and the value of the forward current, on the final temperature of the LED junction temperature. The presented research results may constitute auxiliary materials for designers of lighting luminaires, especially high-power luminaires, where a large number of high-power LED sources are installed in close proximity.
Recent Insights into Low-Surface-Area Catalysts for Hydrogen Production from Ammonia
Authors: Pinzón Marina , Sánchez Paula , de la Osa Ana , Romero Amaya , de Lucas-Consuegra Antonio
Published: November 2022

A potential method of storing and transporting hydrogen safely in a cost-effective and practical way involves the utilization of molecules that contain hydrogen in their structure such as ammonia. Because of its high hydrogen content and carbon-free molecular structure, as well as the maturity of related technology (easy liquefaction), ammonia has gained attention as a “hydrogen carrier” for the generation of energy. Unfortunately, hydrogen production from ammonia requires an efficient catalyst to achieve high conversion at low reaction temperatures. Recently, very attractive results have been obtained with low-surface-area materials. This review paper is focused on summarizing and comparing recent advances in novel, economic and active catalysts for this reaction, paying particular attention to materials with low surface area such as silicon carbide (SiC) and perovskites (ABO3 structure). The effects of the supports, the active phase and the addition of promoters in such low-porosity materials have been analyzed in detail. Advances in adequate catalytic systems (including support and active metal) benefit the perspective of ammonia as a hydrogen carrier for the decarbonization of the energy sector and accelerate the “hydrogen economy”.
Steady-State Analysis and Optimal Design of an LLC Resonant Converter Considering Internal Loss Resistance
Authors: Yoo Jeong-Sang , Gil Yong-Man , Ahn Tae-Young
Published: November 2022

In this paper, a steady-state model of an LLC resonant half-bridge converter with internal loss resistance is proposed, in order to maximize power conversion efficiency, and steady-state characteristic equations of DC voltage gain and input impedance are derived for the optimal design of the converter. First, to confirm the validity of the steady-state characteristic equation and the optimal design process, a prototype converter with a maximum output of 2 kW was designed. Through comparison of simulation, calculation, and experimental results obtained from the prototype test, it is shown that the calculation results proposed in this paper were closer to the experimental results than the calculation results obtained under the lossless condition. In addition, the relationship between the switching frequency and the load current of the prototype was compared, in order to determine the operating range of the switching frequency, which is important in the converter design stage. In this case, it was confirmed that the calculated value reflecting the internal loss showed a close result. In conclusion, we confirm the usefulness of the analysis results reflecting the internal loss resistance proposed in this paper and the optimal design process.
Interference Mitigation for GNSS Receivers Using FFT Excision Filtering Implemented on an FPGA
Authors: Yousif Tasneem , Blunt Paul
Published: November 2022

GNSS receivers process signals with very low received power levels (<−160 dBW) and, therefore GNSS signals are susceptible to interference. Interference mitigation algorithms have become common in GNSS receiver designs in both professional and mass-market applications to combat both unintentional and intentional (jamming) interference. Interference excision filters using fast Fourier transforms (FFTs) have been proposed in the past as a powerful method of interference mitigation. However, the hardware implementations of this algorithm mostly limited their use to military GNSS receivers where greater power and resources were available. Novel implementation of existing FPGA technology should make interference mitigation feasible with limited hardware resources. This paper details the practicalities of implementing excision filters on currently available FPGAs trading off the achievable performance against the required hardware resources. The hardware implementation of the FFT excision mitigation algorithm is validated with the GNSS software receiver. The results indicate that the desired performance of the developed algorithm has achieved the expectations and can provide significant improvement on mitigation techniques in current GNSS receiver hardware. Two hardware implementation designs (fixed-point and float-point data type format) are developed and compared to achieve the optimal design that can provide the best performance (C/No) with the possible minimum hardware resources.
Invasive Alien Plant Species for Use in Paper and Packaging Materials
Authors: Vrabič-Brodnjak Urška , Možina Klemen
Published: November 2022

Invasive plant species can impede the establishment and growth of native plants and affect several ecosystem properties. These properties include soil cover, nutrient cycling, fire regimes, and hydrology. Controlling invasive plants is therefore a necessary, but usually expensive, step in restoring an ecosystem. The sustainability of materials with an emphasis on the use of local resources plays an important role in the circular economy. The use of alternative fibers from invasive plants promotes local production in smaller paper mills that offer the protection of local species and the reduction of waste and invasive plants. A synthesis of the literature is needed to understand the various impacts of invasive plants and their practical control in the context of papermaking applications and to identify associated knowledge gaps. To improve our understanding of the practical application of invasive species in the paper industry, we reviewed the existing literature on invasive plant species in the area of fiber production, printability, coating solution production, dyes, and extracts, and collected information on the major invasive plant species in Europe and the methods used for various applications.
Structural Characteristics of Rehmannia glutinosa Polysaccharides Treated Using Different Decolorization Processes and Their Antioxidant Effects in Intestinal Epithelial Cells
Authors: Ren Heng , Li Zhongyuan , Gao Rui , Zhao Tongxi , Luo Dan , Yu Zihao , Zhang Shuang , Qi Chen , Wang Yaqi , Qiao Hanzhen , Cui Yaoming , Gan Liping , Wang Peng , Wang Jinrong
Published: November 2022

Polysaccharide decolorization is a key determinant of polysaccharide structure. In this study, two purified Rehmannia glutinosa polysaccharides, RGP−1−A and RGP−2−A, were obtained after decolorization using the AB-8 macroporous resin and H2O2, respectively. RGP−1−A (molecular weight (Mw) = 18,964 Da) and RGP−2−A (Mw = 3305 Da) were acidic and neutral heteropolysaccharides, respectively, and were both polycrystalline in structure. FTIR analysis revealed that RGP−1−A was a sulfate polysaccharide, while RGP−2−A had no sulfate group. Experiments on IPEC-1 cells showed that RGPs alleviated oxidative stress by regulating the Nrf2/Keap1 pathway. These findings were confirmed by the upregulation of Nrf2, NQO1, and HO-1; the subsequent increase in the levels of antioxidant indicators (SOD, LDH, CAT, and MDA); and the restoration of mitochondrial membrane potential. Overall, the antioxidant capacity of RGP−1−A was significantly higher than that of RGP−2−A. These results suggest that RGPs may be a potential natural antioxidant and could be developed into functional foods.
Extraction of Phytochemicals from Maypole Apple by Subcritical Water
Authors: Tsai Menghsuan , Zhu Li , Maeda Shinya , Wang Tao , Diono Wahyu , Goto Motonobu , Kanda Hideki
Published: November 2022

The Maypole apple is a new, promising species of small apples with a prominent flavor and deep red flesh and peel. This study divided Maypole apples into outer flesh, inner flesh, and peel, and used subcritical water at 100–175 °C for 10–30 min to extract various phytochemicals (procyanidin B2 (PB2), 5-caffeoylquinic acid (5CQA), and epicatechin). The obtained Maypole apple extracts and extraction residues in this work were analyzed using a SEM, HPLC, FT-IR, and UV-Vis spectrophotometer. Under different subcritical water extraction conditions, this work found the highest extraction rate: to be PB2 from the peel (4.167 mg/mL), 5CQA (2.296 mg/mL) and epicatechin (1.044 mg/mL) from the inner flesh. In addition, this work regressed the quadratic equations of the specific yield through ANOVA and found that temperature is a more significant affecting factor than extraction time. This aspect of the study suggests that phytochemicals could be obtained from the Maypole apple using the new extraction method of subcritical water.
Macroalgae-Derived Multifunctional Bioactive Substances: The Potential Applications for Food and Pharmaceuticals
Authors: Guo Jiameng , Qi Mei , Chen Hongyu , Zhou Chengxu , Ruan Roger , Yan Xiaojun , Cheng Pengfei
Published: November 2022

Macroalgae, as one of the important photosynthetic organisms in the marine environment are widely used in various fields, particularly in the production of food and pharmaceuticals. Given their wide distribution, easy accessibility and high efficiency in fixing carbon dioxide through the carbon concentrating mechanism, they can produce abundant nutriments or metabolites. Moreover, macroalgae can assimilate nitrogen and phosphorus bases on the purification of wastewater, and thus further accumulate high levels of bioactive substances. This review mainly introduces the distribution characteristics of macroalgae and their unique bioactive applications in food, medicine and environmental remediation. Their functional ingredients and bioactive substances are beneficial in food production and/or medicine development. Resource utilization of macroalgae coupled with wastewater and waste gas treatment would provide a sustainable path for bioactive substances production.
Seed Weight and Genotype Influence the Total Oil Content and Fatty Acid Composition of Peanut Seeds
Authors: Li Weilan , Yoo Eunae , Lee SooKyeong , Sung Jungsook , Noh Hyung Jun , Hwang So Jeong , Desta Kebede Taye , Lee Gi-An
Published: November 2022

Peanut, an important oilseed crop cultivated worldwide as a dietary food, is a good food source with health benefits. To explore the potential benefits of peanuts as a food resource, 301 peanut accessions were evaluated to determine the effect of seed weight and genotype on total oil content and fatty acid composition. Total oil was extracted using the Soxhlet method and fatty acids were analyzed by gas chromatography mass spectrometry. Wide variations in the 100-seed weight, total oil content, and fatty acid profile were observed among genotypes and accession types. An effect of seed weight on the fatty acid composition of peanut seeds was observed. Increases in the oleic acid content and decreases in the linoleic acid content occurred in association with increases in the 100-seed weight. Moreover, the 100-seed weight, total oil content, and individual and total fatty acid contents, except arachidic acid, differed significantly (p < 0.001 or 0.05) among the accession types of landrace, cultivar, breeding line, and unknown. The discovery of this high diversity could contribute to further studies of peanut domestication and evolutionary classification. Our findings are important for the selection of peanut seeds with health benefits and development of new varieties of peanut with health benefits.
Nutritional Composition of Tonka Bean (Dipteryx odorata) and Its Application as an Elder-Friendly Food with Gelling Agent
Authors: Kim Dah-Sol , Iida Fumiko
Published: November 2022

(1) Background: The purpose of this study was to compare the nutritional characteristics of Tonka beans according to the cooking method and to prove the feasibility of application as an elder-friendly food. (2) Methods: After analyzing the nutritive components, antioxidant activity, and anti-diabetic activity of raw, boiled, and roasted Tonka beans, custards, to which roasted Tonka beans were added, were prepared using a gelling agent to meet the KS viscosity standards (≤1500 mPa.s). (3) Results: The cooking methods decreased the nutritive factors in Tonka beans. However, while boiling caused significant losses, roasting led to minor losses. However, because the elderly should avoid eating uncooked foods for safety reasons, semi-solid elder-friendly food was manufactured with roasted Tonka beans, which caused minor losses compared to boiling. The concentration of each gelling agent satisfying the KS viscosity was less than 0.745% of locust bean gum, 0.734% of κ-carrageenan, and 1.094% of agar. (4) Conclusions: Roasted Tonka beans are suitable for use as an elder-friendly food for the health and safety of the elderly, and it will be possible to promote balanced food intake through the use of gelling agents for the elderly who have difficulty swallowing.
Wrist Rigidity Evaluation in Parkinson’s Disease: A Scoping Review
Authors: Alves Camille Marques , Rezende Andressa Rastrelo , Marques Isabela Alves , Mendes Luanne Cardoso , de Sá Angela Abreu Rosa , Vieira Marcus Fraga , Júnior Edgard Afonso Lamounier , Pereira Adriano Alves , Oliveira Fábio Henrique Monteiro , de Souza Luciane Pascucci Sande , Bourhis Guy , Pino Pierre , Andrade Adriano de Oliveira , Morère Yann , Naves Eduardo Lázaro Martins
Published: November 2022

(1) Background: One of the main cardinal signs of Parkinson’s disease (PD) is rigidity, whose assessment is important for monitoring the patient’s recovery. The wrist is one of the joints most affected by this symptom, which has a great impact on activities of daily living and consequently on quality of life. The assessment of rigidity is traditionally made by clinical scales, which have limitations due to their subjectivity and low intra- and inter-examiner reliability. (2) Objectives: To compile the main methods used to assess wrist rigidity in PD and to study their validity and reliability, a scope review was conducted. (3) Methods: PubMed, IEEE/IET Electronic Library, Web of Science, Scopus, Cochrane, Bireme, Google Scholar and Science Direct databases were used. (4) Results: Twenty-eight studies were included. The studies presented several methods for quantitative assessment of rigidity using instruments such as force and inertial sensors. (5) Conclusions: Such methods present good correlation with clinical scales and are useful for detecting and monitoring rigidity. However, the development of a standard quantitative method for assessing rigidity in clinical practice remains a challenge.
Cancer Prevention Sense Making and Metaphors in Young Women’s Invented Stories
Authors: Lemmo Daniela , Martino Maria Luisa , Freda Maria Francesca
Published: November 2022

Despite the proven effectiveness of cancer prevention, the literature highlights numerous obstacles to the adoption of screening, even at a young age. In cancer discourse, the metaphor of war is omnipresent and reflects an imperative demand to win the war against disease. From the psychodynamic perspective, the risk of cancer forecasts an emotionally critical experience for which it is important to study mental representations concerning illness and health care. Through the creation of an invented story that offers a framework for imagination, our aim is to understand what the relationship with preventive practices in oncology means for young women and how this relationship is revealed by their metaphors. A total of 58 young women voluntarily participated in the present research, answering a narrative prompt. The stories written by the participants were analyzed using qualitative methodology to identify construct, themes and metaphors. Our findings identify four constructs: the construction of a defense: youth as protection; the attribution of blame about cancer risk; learning from experience as a prevention activator; and from inaccessibility to access to preventive practices: the creation of engagement. The construction of an invented story allows us to promote a process of prefiguration on the bodily, affective and thought planes invested in preventive practice and brings out the use of metaphors to represent cancer risk and self-care. The results allow us to think about the construction of interventions to promote engagement processes in prevention from an early age.