bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution towards Coordinated Multi-Point Architecture in Self-Organizing Networks for Small Cell Enhancement Systems
Authors: Wu Chia-Lun , Lu Tsung-Tao , Lee Chin-Tan , Sun Jwo-Shiun , Lin Hsin-Piao , Hwang Yuh-Shyan , Sung Wen-Tsai
Published: May 2023

This paper explores applications of the coordinated multi-point (CoMP) architecture operation of enhanced node B (eNB) in wireless communication networks featuring device-to-device (D2D) signaling. This is applied to cellular phone coverage for rapid mass transit systems, such as the Taiwan high speed rail transport system, and indoor public environments. The paper is based on formulas pertaining to the link between budget design and guidelines, as well as principles and theories of engineering practice, allowing designers to analyze and fully control the uplink and downlink signals and output power of fiber repeaters linking cellular phones to base stations. Finally, we employ easily installed cellular-over-fiber optic solutions for a small cell enhancement (SCE) system with novel architecture based on a leakage coaxial cable system using LTE-A technology. As a result, we successfully applied enhanced coverage designs for distributed antenna systems. These can be used to create self-organizing networks (SoN) for an Internet of Things.
A Complex Empirical Mode Decomposition for Multivariant Traffic Time Series
Authors: Shen Guochen , Zhang Lei
Published: May 2023

Data-driven modeling methods have been widely used in many applications or studies of traffic systems with complexity and chaos. The empirical mode decomposition (EMD) family provides a lightweight analytical method for non-stationary and non-linear data. However, a large amount of traffic data in practice are usually multidimensional, so the EMD family cannot be used directly for those data. In this paper, a method to calculate the extremum point and the envelope-like function (series) from the complex function (series) is proposed so that the EMD family can be applied to two-variate traffic time-series data. Compared to the existing multivariate EMD, the proposed method has advantages in computational burden, flexibility and adaptivity. Two-dimensional trajectory data were used to test the method and its oscillatory characteristics were extracted. The decomposed feature can be used for data-driven traffic analysis and modeling. The proposed method also extends the utilization of EMD to multivariate traffic data for applications such as traffic data denoising, pattern recognition, traffic flow dynamic evaluation, traffic prediction, etc.
Aggregate Entity Authentication Identifying Invalid Entities with Group Testing
Authors: Hirose Shoichi , Shikata Junji
Published: June 2023

It is common to implement challenge-response entity authentication with a MAC function. In such an entity authentication scheme, aggregate MAC is effective when a server needs to authenticate many entities. Aggregate MAC aggregates multiple tags (responses to a challenge) generated by entities into one short aggregate tag so that the entities can be authenticated simultaneously regarding only the aggregate tag. Then, all associated entities are valid if the pair of a challenge and the aggregate tag is valid. However, a drawback of this approach is that invalid entities cannot be identified when they exist. To resolve the drawback, we propose group-testing aggregate entity authentication by incorporating group testing into entity authentication using aggregate MAC. We first formalize the security requirements and present a generic construction. Then, we reduce the security of the generic construction to that of aggregate MAC and group testing. We also enhance the generic construction to instantiate a secure scheme from a simple and practical but weaker aggregate MAC scheme. Finally, we show some results on performance evaluation.
Scientific Approaches to Solving the Problem of Joint Processes of Bubble Boiling of Refrigerant and Its Movement in a Heat Pump Heat Exchanger
Authors: Osintsev Konstantin , Aliukov Sergei , Kovalev Anton , Bolkov Yaroslav , Kuskarbekova Sulpan , Olinichenko Alyona
Published: May 2023

The joint processes of bubble boiling and refrigerant movement in heat pump tubes are considered. A coil located on the back side of the photovoltaic panel (PVP) is used as an additional heating surface. A mathematical model of the theoretical determination of the temperature on the front surface of the PVP cooled by freon in the coil from the back side has been created. A feature of the numerical simulation of bubble boiling of refrigerant in a coil was the insufficiently detailed study of the process and the lack of references to the results obtained in earlier work. The authors have clarified the boundary conditions and assumptions for numerical simulation of the bubble boiling process of refrigerant R407C. The results were compared with the theoretically found values, and later used in the design of an energy complex consisting of a heat pump and a photovoltaic panel. The mathematical model of theoretical calculation of the PVP temperature and the methodology for constructing a numerical model of bubble boiling of refrigerant as part of the methodology for designing energy technology complexes based on the authors’ plan to present a unified methodology for energy technology complexes for desalination of seawater based on other types of renewable energy sources.
Compensation-Voltage-Injection-Based Neutral-Point Voltage Fluctuation Suppression Method for NPC Converters
Authors: Chen Guo , Gong Chunyang , Bao Jun , Zhu Lihua , Wang Zhixin
Published: May 2023

Three-level neutral-point clamped (NPC) inverters are widely used in the new energy power generation, motor drive, and many other occasions. However, the neutral-point voltage imbalance of an NPC inverter will affect the output of the inverter system, and the control of the neutral point voltage has become a popular research topic. In this paper, a compensation-voltage-injection-based neutral-point voltage balancing method is proposed. During the switching cycle, the average value model of the neutral-point current under different voltage vectors is applied to calculate the value of the compensation voltage that needs to be injected. The self-balance of the neutral-point voltage based on a switching cycle is realized, and the influence of modulation ratio and power factor on equalization ability is discussed. A MATLAB/Simulink simulation model and a small power prototype are established to verify the effectiveness of the method, and the simulation and experimental results show that the proposed method can effectively suppress the neutral-point voltage fluctuation in a wide range of modulation ratios and power factors.
Cryogenic Hydrogen Jet and Flame for Clean Energy Applications: Progress and Challenges
Authors: Clarke Jac , Dettmer Wulf , Wen Jennifer , Ren Zhaoxin
Published: May 2023

Industries across the world are making the transition to net-zero carbon emissions, as government policies and strategies are proposed to mitigate the impact of climate change on the planet. As a result, the use of hydrogen as an energy source is becoming an increasingly popular field of research, particularly in the aviation sector, where an alternative, green, renewable fuel to the traditional hydrocarbon fuels such as kerosene is essential. Hydrogen can be stored in multiple ways, including compressed gaseous hydrogen, cryo-compressed hydrogen and cryogenic liquid hydrogen. The infrastructure and storage of hydrogen will play a pivotal role in the realisation of large-scale conversion from traditional fuels, with safety being a key consideration. This paper provides a review on previous work undertaken to study the characterisation of both unignited and ignited hydrogen jets, which are fundamental phenomena for the utilisation of hydrogen. This includes work that focuses on the near-field flow structure, dispersion in the far-field, ignition and flame characteristics with multi-physics. The safety considerations are also included. The theoretical models and computational fluid dynamics (CFD) multiphase and reactive flow approaches are discussed. Then, an overview of previous experimental work is provided, before focusing the review on the existing computational results, with comparison to experiments. Upon completion of this review, it is highlighted that the complex near-field physics and flow phenomena are areas lacking in research. The near-field flow properties and characteristics are of significant importance with respect to the ignition and combustion of hydrogen.
Experimental Investigation of Gravity Effect on a Vapor Compression Heat Pump System
Authors: Huang Zhanfeng , Li Tingxun
Published: May 2023

Vapor compression heat pumps have the potential to meet the future development requirements of thermal management in aerospace due to the ability to achieve high heat flux dissipation, precise temperature control, and a more compact and lightweight structure. In this study, a variable-angle test stand was constructed to investigate the effect of gravity on the performance, temperature distribution, and oil circulation rate of a vapor compression heat pump system in a ground environment. The results showed that the system could operate stably at various inclination angles, with the compressor exhibiting the lowest power consumption at an inclination angle of 90° and the maximum coefficient of performance (COP) of the vapor compression heat pump reaching 5.5. The system flow rate exhibited a sinusoidal curve with a 10.7% variation relative to the initial flow rate as the inclination angle increased. The evaporating temperature, condensing temperature, and compressor discharge temperature of the system were approximately symmetrical relative to the inclination angle of 180°. At inclination angles ranging from 90 to 270°, the oil circulation rate was highly sensitive to gravity changes and remained at a high level. The oil circulation rate agreed well with the change in subcooling/superheating, yet a rise in the oil circulation rate resulted in a decrease in COP.
A Comprehensive Survey of HVDC Protection System: Fault Analysis, Methodology, Issues, Challenges, and Future Perspective
Authors: Pragati Abha , Mishra Manohar , Rout Pravat Kumar , Gadanayak Debadatta Amaresh , Hasan Shazia , Prusty B. Rajanarayan
Published: May 2023

The extensive application of power transfer through high-voltage direct current (HVDC) transmission links in smart grid scenarios is due to many factors such as high-power transfer efficiency, decoupled interconnection, control of AC networks, reliable and flexible operation, integration of large wind and photovoltaic (PV)-based off-shore and on-shore farms, cost-effectiveness, etc. However, it is vital to focus on many other aspects like control, protection, coordinated operation, and power management to acquire the above benefits and make them feasible in real-time applications. HVDC protection is needed to focus further on innovative and devoted research because the HVDC system is more vulnerable to system faults and changes in operational conditions in comparison to AC transmission because of the adverse effects of low DC-side impedances and sensitive semi-conductor-based integrated power electronics devices. This paper provides a comprehensive review of the techniques proposed in the last three decades for HVDC protection, analyzing the advantages and disadvantages of each method. The review also examines critical findings and assesses future research prospects for the development of HVDC protection, particularly from the perspective of smart-grid-based power systems. The focus of the review is on bridging the gap between existing protection schemes and topology and addressing the associated challenges and issues. The aim is to inform power engineers and researchers about potential research avenues to tackle the challenges in HVDC protection in smart-grid-based power systems.
3D Solar Irradiance Model for Non-Uniform Shading Environments Using Shading (Aperture) Matrix Enhanced by Local Coordinate System
Authors: Araki Kenji , Ota Yasuyuki , Nagaoka Akira , Nishioka Kensuke
Published: May 2023

Building-integrated photovoltaics (BIPVs) and vehicle-integrated photovoltaics (VIPVs) receive solar irradiance through non-uniform shading objects. Standard scalar calculations cannot accurately determine the solar irradiance of BIPV and VIPV systems. This study proposes a matrix model using an aperture matrix to accurately calculate the horizontal and vertical planes affected by non-uniform shading objects. This can be extended to the solar irradiance on a VIPV by applying a local coordinate system. The 3D model is validated by a simultaneous measurement of five orientations (roof and four sides, front, left, tail, and right) of solar irradiance on a car body. An accumulated logistic function can approximate the shading probability. Furthermore, the combined use of the 3D solar irradiance model is effective in assessing the energy performance of solar electric vehicles in various zones, including buildings, residential areas, and open spaces. Unlike standard solar energy systems, the energy yield of a VIPV is affected by the shading environment. This, in turn, is affected mainly by the location of vehicle travel or parking in the city rather than by the climate zones of the city.
Research on Unsteady Inverse Heat Conduction Based on Dynamic Matrix Control
Authors: Huang Weichao , Li Jiahao , Liu Ding
Published: May 2023

For the unsteady multi-boundary inverse heat conduction problem, a real-time solution method for boundary heat flux based on dynamic matrix control is proposed in the paper. The method solves the heat flux at the boundary in real-time by measuring the temperature information at the measurement points of the heat transfer system. A two-dimensional direct heat conduction model of the heat transfer system is established in the paper, and is solved by the finite difference method to obtain the temperature information of the measurement points under any heat flux boundary. Then, the correspondence between the heat flux of boundary and the temperature information is presented by means of a step-response model. The regularization parameters are introduced into the method to improve the stability of the inversion process, and the effect of real-time inversion on the heat flux of the boundary is achieved through rolling optimization. The experimental results show that the proposed method can achieve real-time inversion of the heat fluxes of the two-dimensional boundary with good accuracy.
Evaluation of the Impact of Window Parameters on Energy Demand and CO2 Emission Reduction for a Single-Family House
Authors: Jezierski Walery , Zukowski Miroslaw
Published: May 2023

This article deals with the determination of the impact of selected parameters on energy consumption for heating and cooling purposes and CO2 emissions. Mathematical modelling combined with planning a computational experiment was adopted as the research method. The database for creating the models was developed using building energy simulations performed with DesignBuilder software. A single-family house with an area of 101 m2 was the subject of this study. Four deterministic mathematical models for the estimation of annual energy demand for heating, cooling, total final energy demand, and CO2 emissions were developed. Four parameters affecting the energy balance of the house: the area of the glazing system (three levels), U-value of windows (two-, three- and four-pane), U-value of external walls (0.1, 0.15, 0.2 W/m2K) and location (Warsaw, Berlin, Paris) were considered. The article discusses in detail the influence of individual factors on the energy demand and their common interactions. It was found that the level of thermal insulation of the glazing system plays the most important role in saving energy. This factor was the only one to show a stable and significant reduction in house energy demand, and thus a reduction in CO2 emissions for all four objective functions.
Intelligent Prediction of Transformer Loss for Low Voltage Recovery in Distribution Network with Unbalanced Load
Authors: Dai Zikuo , Shi Kejian , Zhu Yidong , Zhang Xinyu , Luo Yanhong
Published: May 2023

In order to solve the problem of low voltage caused by unbalanced load in the distribution network, a transformer loss intelligent prediction model under unbalanced load is proposed. Firstly, the mathematical model of a transformer with an unbalanced load is established. The zero-sequence impedance and neutral line current of the transformer are calculated by using the Chaos Game Optimization algorithm (CGO), and the correctness of the mathematical model is proved by using actual data. Then, the correlation among network input variables is eliminated by using Principal Component Analysis (PCA), so the number of network input variables is decreased. At the same time, Sparrow Search Algorithm (SSA) is used to optimize the initial weight and threshold of the BP network, and an accurate transformer loss prediction model based on the PCA-SSA-BP is established. Finally, compared with the transformer loss prediction model based on BP network, Genetic Algorithm optimized BP network (GA-BP), Particle Swarm optimized BP network (PSO-BP) and Sparrow Search Algorithm optimized BP network (SSA-BP), the transformer loss prediction model based on PCA-SSA-BP network has been proven to be accurate by using actual data and it is helpful for low-voltage recovery in the distribution network.
Coupling Design and Validation Analysis of an Integrated Framework of Uncertainty Quantification
Authors: Pang Bo , Su Yuhang , Wang Jie , Deng Chengcheng , Huang Qingyu , Zhang Shuang , Wu Bin , Lin Yuanfeng
Published: May 2023

The uncertainty quantification is an indispensable part for the validation of the nuclear safety best-estimate codes. However, the uncertainty quantification usually requires the combination of statistical analysis software and nuclear reactor professional codes, and it consumes huge computing resources. In this paper, a design method of coupling interface between DAKOTA Version 6.16 statistical software and nuclear reactor professional simulation codes is proposed, and the integrated computing workflow including interface pre-processing, code batching operations, and interface post-processing can be realized. On this basis, an integrated framework of uncertainty quantification is developed, which is characterized by visualization, convenience, and efficient computing. Meanwhile, a typical example of small-break LOCA analysis of the LOBI test facility was used to validate the reliability of the developed integrated framework of uncertainty quantification. This research work can provide valuable guidance for developing an autonomous uncertainty analysis platform in China.
A Review of the Energy Sector as a Key Factor in Industry 4.0: The Case of Spain
Authors: García-Moreno Sonia , López-Ruiz Víctor-Raúl
Published: June 2023

Technological development has profoundly marked the evolution of the economy. The constant changes brought about by scientific and technological advances have been decisive in the transition from an analogue to a digital world. In this context, the impact of the fourth industrial revolution (or Industry 4.0) manifests itself in many ways. Environmental impact is one of these. The energy sector has been evolving and changing just like the economy and society. Therefore, a study of this sector, and of the other related elements, is of interest to better understand the 4.0 concept. The promotion of sustainability at both the political and social levels has led to changes in different areas, such as the productive vision, the use of green energies, and the implementation of green taxes. Energy as a key factor in Industry 4.0 involves studying it both quantitatively and qualitatively. This is to understand the lights and shadows that the concept currently presents. Therefore, this work aims to bring the reality of the energy sector closer to reality, both in its positive and negative aspects, considering the main factors of incidence, to show the strengths and weaknesses that can be deduced.
Planning and Optimizing the Replacement Strategies of Power Transformers: Literature Review
Authors: Balanta Jefferson , Rivera Sergio , Romero Andrés , Coria Gustavo
Published: June 2023

The power transformer is one of the most critical assets in power systems; therefore, planning and optimizing the economic investment for its replacement is crucial for the financial efficiency of the utility. A compilation of the main approaches reported in the literature for the replacement of oil-immersed power transformers is presented in this article. A chronological description of procedures presented in the literature for the determination of risk index, useful life evaluation, and transformer replacements is provided. Methodologies that use the theoretical basis of the degree of polymerization of the solid insulation of the units through the oxidation aging process to estimate their condition bring together the best tools currently available to achieve this objective. However, it is important and pertinent to complement these methodologies by considering the aging processes by pyrolysis and hydrolysis together and by incorporating economic analyses for appropriate replacement and management of these aged units.
Development and Research of a Medium Vertical Dipole Electromagnetic Pulse Simulator
Authors: Jia Wei , Mei Kaisheng , Cheng Le , Wu Wei , Chen Zhiqiang , Guo Fan , Wang Yi , Shi Ling , Wang Wei , Shi Yuewu , Zhu Xiangqin , Wu Gang , Li Yaoyao
Published: June 2023

In this paper, the design of a self-developed EMP simulator with a 5 m height and an inverted conducting mono-cone antenna with a cone half-angle of 32° is introduced. The experimental region of the simulator is a circular area of 25 m in diameter around the cone vertex. Two feeding modes, feed-in over the ground and feed-in under the ground, are realized by two different high-voltage pulse sources. It can be concluded through radiation field testing that the radiation field waveform generated by the simulator has a rise time of 2–3 ns and a half-width of about 25 ns, meeting the specifications of the EMP experimental waveform in the IEC61000-2-9 standard. Meanwhile, the differences between the engineering implementation of the simulator and its ideal structure during the design process can lead to some distortion issues in the antenna radiation characteristics and the electromagnetic radiation field it generates. The radiation field waveform and the distribution of the EMP field generated by the simulator under different feeding methods, antenna wire quantities, antenna end processing methods, and different antenna resistive loading were studied, and the changes in the radiation field waveform and field distribution with different angles and distances of the monitoring point were analyzed. Based on the measurement results, the radiation characteristics of the antenna and the factors that affect the waveform of the field were studied and analyzed. Through the aforementioned work, a comprehensive understanding of the performance, radiation characteristics, and engineering factors affecting the electromagnetic environment generated by the simulator has been obtained. On this basis, the parameters of the antenna wire quantity, antenna end processing method, and test point position of the designed simulator were reconfirmed and optimized. In summary, this work has important reference significance for mastering the development technology of such simulators, understanding their antenna radiation characteristics, and conducting EMP-related assessments and effect experiments in the future.
Thermal-Mass and Microbiological Analysis of Forced Air Flow through the Stone Heat Accumulator Bed
Authors: Kurpaska Sławomir , Wolny-Koładka Katarzyna , Malinowski Mateusz , Tomaszek Klaudia , Latała Hubert
Published: June 2023

Heat storage in systems integrated with renewable energy sources in facilities can reduce the consumption of fossil fuels, cut maintenance costs, and decrease greenhouse gas emissions from buildings and other objects. One of the possible solutions is the use of a stone heat accumulator for short-term heat storage and the use of this deposit in the ventilation process of the facility. During short-term air flow through the porous material from which an accumulator bed is made, there is an exchange of heat and mass between the flowing air and the bed particles. In the long term, the use of an accumulator can lead to an increase in dust and the development of pathogenic microorganisms, endangering human life and health. Therefore, understanding the factors influencing the efficient use of a stone deposit is very important. The aim of this study is to calculate the changes in thermal-mass parameters in the air flowing out of the stone accumulator and to assess the effect of long-term stone accumulator use on the content of microorganisms and dust concentration in bioaerosol. The application of the heat storage system in the stone bed leads to the formation of strictly controlled microclimatic conditions, and the tested air does not constitute a threat to the people staying in the object. The concentration standards of PM10 and PM2.5 exceeded the limit values (PM2.5 = 20 μg∙m−3 and PM10 = 40 μg∙m−3), and, thus, the air in the studied greenhouse was classified as polluted. The analysis also showed that, for the analyzed conditions, a 20% increase in the initial temperature of the accumulator bed results in a nearly 20% increase in the outlet air temperature.
Thermal Analysis of Magneto-Natural Convection Flows within a Partially Thermally Active Rectangular Enclosure
Authors: Saha Suvash C. , Islam Shams ul , Zia Zahida , Saleem M. , Ahmad Shafee
Published: June 2023

In this study, we numerically investigate heat transfer enhancement in a partially thermally active rectangular enclosure. The enclosure is filled with a ternary hybrid nanofluid (water, Carbon Nanotube, Al2O3, and Graphene). It is subjected to a magnetic field and uniform internal heat generation. The study also investigates the effect of magnetic field strength and direction on the natural convection flow, which arises from density fluctuations caused by partial heating of the left vertical wall. To solve the dimensionless governing equations, the finite element approach is employed. The parameters studied in detail include Rayleigh number (Ra), Hartmann number (Ha), nanoparticle volume fraction (ϕ), and heat generation coefficient (λ). The findings are presented graphically for the range of the parameters as follows: 103≤Ra ≤106, 0≤Ha≤20, 0.01≤ϕ≤0.05, and 0≤λ≤15. It is noted that these parameters have an impact on heat transfer enhancement, flow patterns, and temperature fields. The results show that the average Nusselt number (Nu¯) increases with an increasing value of ϕ. Moreover, it has been noted that Nu¯ decreases as the value of Ha increases, and the impact becomes more obvious at higher Ra values. Finally, the influence of the heat generation coefficient on the heat transfer rate inside an enclosure is examined.
Determination of Geometrical Deviations of Large-Size Crankshafts with Limited Detection Possibilities Resulting from the Assumed Measuring Conditions
Authors: Nozdrzykowski Krzysztof , Grządziel Zenon , Grzejda Rafał , Stępień Mateusz
Published: June 2023

This article deals with the geometrical deviation measurements of crankshafts of large marine engines fuelled with conventional or alternative fuels, taking into account the problem of their deformability. Since the detectability of geometrical deviations of a crankshaft supported by prisms depends largely on the support conditions assumed and the parameters of the method, the study was carried out for two cases of crankshaft support. The first case concerned measurements of the main journals of a crankshaft seated on a set of supports pre-positioned at an equal height. In contrast, the second case involved measurements of the main journals of a crankshaft seated on supports pre-positioned at various heights. In particular, the research focused on evaluating the effect of sensor location angle on the results of measurements of deviations and contour profiles of the crankshaft main journal system. The results of the research are the developed procedures, the application of which in practical measurements under workshop conditions, where there is no access to coordinate measuring machines, enables correct interpretation of the measurement results and evaluation of the geometrical state of the measured crankshaft.
Impact of Hydrogen Mixture on Fuel Consumption and Exhaust Gas Emissions in a Truck with Direct-Injection Diesel Engine
Authors: Wang Muxi , Matsugi Akira , Kondo Yoshinori , Sakamoto Yosuke , Kajii Yoshizumi
Published: June 2023

Hydrogen addition affects the composition of exhaust gases in vehicles. However, the effects of hydrogen addition to compression ignition engines in running vehicles have not been evaluated. Hydrogen-mixed air was introduced into the air intake of a truck equipped with a direct-injection diesel engine and running on a chassis dynamometer to investigate the effect of hydrogen addition on fuel consumption and exhaust gas components. The reduction in diesel consumption and the increase in hydrogen energy share (HES) showed almost linear dependence, where the percentage decrease in diesel consumption is approximately 0.6 × HES. The percentage reduction of CO2 showed a one-to-one relationship to the reduction in diesel consumption. The reduction in emissions of CO, PM, and hydrocarbons (except for ethylene) had one to one or a larger correlation with the reduction of diesel consumption. On the other hand, it was observed that NOx emissions increased, and the percentage increase of NOx was 1.5~2.0 times that of HES. The requirement for total energy supply was more when hydrogen was added than for diesel alone. In the actual running mode, only 50% of the energy of added hydrogen was used to power the truck. As no adjustments were made to the engine in this experiment, a possible disadvantage that could be improved by adjusting the combustion conditions.
Issues Concerning Manufacture and Recycling of Lead
Authors: Bača Petr , Vanýsek Petr
Published: June 2023

This article gives an overview of historical and present uses of lead against the backdrop of gradual realization that lead is an environmental hazard. In this paper the lead in the lead-acid batteries is investigated from the view of its present use. This use continues because there does not exist economical and practical alternative to lead for this purpose. In fact the use is still steadily increasing. This may not be a concern as it has been demonstrated that in countries with strong economies, recycling of lead from the batteries can near 100%. Here, we take a look at reality, by comparing select countries on both sides of the economic spectrum. In poorer countries, recycling suffers more on the safe and clean side of the process. Historical uses of lead are also reviewed, as well as a new approach of using lead compounds in soluble lead flow batteries.
Real-Time Detection of Bud Degeneration in Oil Palms Using an Unmanned Aerial Vehicle
Authors: Vázquez-Ramírez Alexis , Mújica-Vargas Dante , Luna-Álvarez Antonio , Matuz-Cruz Manuel , Rubio José de Jesus
Published: June 2023

This paper presents a novel methodology for the early detection of oil palm bud degeneration based on computer vision. The proposed system uses the YOLO algorithm to detect diseased plants within the bud by analyzing images captured by a drone within the crop. Our system uses a drone equipped with a Jetson Nano embedded system to obtain complete images of crops with a 75% reduction in time and with 40% more accuracy compared to the traditional method. As a result, our system achieves a precision of 92% and a recall of 96%, indicating a high detection rate and a low false-positive rate. In real-time detection, the system is able to effectively detect diseased plants by monitoring an entire hectare of crops in 25 min. The system is also able to detect diseased plants other than those it was trained on with 43% precision. These results suggest that our methodology provides an effective and reliable means of early detection of bud degeneration in oil palm crops, which can prevent the spread of pests and improve crop production.
Assessing Forest Vulnerability to Climate Change Combining Remote Sensing and Tree-Ring Data: Issues, Needs and Avenues
Authors: Italiano Santain S. P. , Camarero Jesús Julio , Colangelo Michele , Borghetti Marco , Castellaneta Maria , Pizarro Manuel , Ripullone Francesco
Published: June 2023

Forests around the world are facing climate change. Increased drought stress and severe heat waves in recent decades have negatively impacted on forest health, making them more vulnerable and prone to dieback and mortality phenomena. Although the term vulnerability is used to indicate an increased susceptibility of forests to climate change with a worsening of their vigour status that can compromise their ability to respond to further climate extreme events, there are still uncertainties on how to evaluate it. Indeed, evaluation of forest vulnerability is complex both because of some critical issues in the estimation methods used and because of the multiple factors influencing the response of forests to ongoing climate change. A way to assess the vulnerability to environmental stresses is by combining remote sensing and dendroecological data. However, these two approaches entail multiple uncertainties, including growth/photosynthetic relationships, carbon allocation dynamics, biases of tree-ring data and noisy remote sensing data, which require further clarification for proper monitoring of pre- and post-drought forest trajectories. Our review aims to create an overview of the current literature and knowledge to understand the critical issues, needs and possible solutions that forest vulnerability research is addressing. We focus on Mediterranean forests located in a climate warming hotspot and showing a high vulnerability to increased aridification.
High-Resolution Digital Soil Maps of Forest Soil Nitrogen across South Korea Using Three Machine Learning Algorithms
Authors: An Yoosoon , Shim Woojin , Jeong Gwanyong
Published: June 2023

Reliable estimation of the forest soil nitrogen spatial distribution is necessary for effective forest ecosystem management. This study aimed to develop high-resolution digital soil maps of forest soil nitrogen across South Korea using three powerful machine learning methods to better understand the spatial variations of forest soil nitrogen and its environmental drivers. To achieve this, the study used national-level forest soil nitrogen data and environmental data to construct various geographic and environmental variables including geological, topographic, and vegetation factors for digital soil mapping. The results show that of the machine learning methods, the random forest model had the best performance at predicting total soil nitrogen in the A and B horizons, closely followed by the extreme gradient-boosting model. The most critical predictors were found to be geographic variables, quantitatively confirming the significant role of spatial autocorrelation in predicting soil nitrogen. The digital soil maps revealed that areas with high elevation, concave slopes, and deciduous forests had high nitrogen contents. This finding highlights the potential usefulness of digital soil maps in supporting forest management decision-making and identifying the environmental drivers of forest soil nitrogen distribution.
Fermentation of Cocoa (Theobroma cacao L.) Pulp by Laetiporus persicinus Yields a Novel Beverage with Tropical Aroma
Authors: Klis Victoria , Pühn Eva , Jerschow Jeanny Jaline , Fraatz Marco Alexander , Zorn Holger
Published: May 2023

Cocoa pulp represents an interesting by-product of cocoa production, with an appealing flavor. We developed a non-alcoholic beverage via the submerged fermentation of 10% pasteurized cocoa pulp in water with Laetiporus persicinus for 48 h; the product was characterized by tropical fruity notes such as coconut, mango, passion fruit and peach. The overall acceptance of the beverage compared to the non-fermented medium, as rated by a panel, increased from 2.9 to 3.7 (out of 5.0 points) for odor and from 2.1 to 4.2 for taste. (R)-Linalool (flowery, fruity), methyl benzoate (green, sweet), 2-phenylethanol (rose, sweet), 5-butyl-2(5H)-furanone (coconut, peach) and (E)-nerolidol (flowery, woody) contributed to the overall aroma with odor activity values of >1. During aroma dilution analysis, further substances with coconut, passion fruit and peach-like notes were perceived and structurally assigned to the group of sesquiterpenoids. The fermentation generated a highly interesting beverage using only 10% of the valuable cocoa pulp. The aroma formation via the fungus L. persicinus on cocoa pulp is of great interest for further research as an example of the formation of substances not yet described in the literature.
Layer Inoculation as a New Technology to Resist Volatile Fatty Acid Inhibition during Solid-State Anaerobic Digestion: Methane Yield Performance and Microbial Responses
Authors: Gao Xingliang , Li Zhuowu , Zhang Keqiang , Kong Dewang , Gao Wenxuan , Liang Junfeng , Liu Fuyuan , Du Lianzhu
Published: June 2023

Solid-state anaerobic digestion is easily inhibited by high volatile fatty acid induced by high total solids, although it is a promising technology. Previous studies on volatile fatty acid inhibition mainly focused on total solid content, co-digestion substrates, and external additives. The present study proposed a new inoculation method named layer inoculation and compared it to premixing inoculation in the solid-state anaerobic digestion of pig manure and maize straw. The results showed that the cumulative CH4 yields from layer inoculation (211.5 mL/g-VS) were 5.64 times more than premixing inoculation (37.5 mL/g-VS) under a low inoculation ratio (25%), with the values of total volatile fatty acid being greater than 30.0 mg/g. The concentrations of total VFAs and acetic acid from layer inoculation decreased dramatically during days 18–43. Layer inoculation also showed wider specific methane yield peaks and shorter startup times than premixing inoculation. Methanosphaerula and Methanothrix were the most dominant genera, while the genus Methanosphaerula did not correlate with volatile fatty acids, pH, or total ammonia nitrogen. The hydrogenotrophic methanogen pathway was predominant during solid-state anaerobic digestion; the shift from hydrogenotrophic to acetoclastic occurred in premixing inoculation, and it was stable in layer inoculation (61.20–68.88%). Overall, layer inoculation can effectively enhance methane production under high volatile fatty acid concentrations compared with premixing inoculation.
Improving Expression of Pepsinogen A from Homo sapiens in Aspergillus niger by Using a Multi-Copy Gene Knock-in Strategy
Authors: Chen Jie , Gui Ling , Chen Boyu , Sun Yuang , Zhao Yongcan , Lu Fuping , Li Ming
Published: June 2023

Pepsinogen A (PGA) plays an important role in the treatment of human gastrointestinal diseases. At present, PGA is mainly extracted from pig stomach, so its source is very limited and its price is very expensive. Production of PGA by microbial fermentation using an engineered strain with high PGA yield would be an ideal solution. This paper presents a new system for the high-level expression of PGA from Homo sapiens (hPGA) in Aspergillus niger. The hPGA5 gene codon was optimized according to the codon bias of A. niger and then connected to a strong promoter and signal peptide to construct an hPGA5 expression cassette. An ingenious multi-copy knock-in expression strategy mediated by the CRISPR/Cas9 tool was used to improve the production of hPGA in A. niger. By optimizing the copy number and integration sites of the hPGA5 gene, an engineering strain with a high yield of hPGA was constructed. After shake-flask fermentation for 7 d, the enzyme activity of recombinant hPGA reached 542.3 U/mL, which is the highest known activity. This lays a foundation for the production of hPGA by microbial fermentation.
Exopolysaccharide from Lactiplantibacillus plantarum YT013 and Its Apoptotic Activity on Gastric Cancer AGS Cells
Authors: Zhang Rentao , Zhou Zhongkun , Ma Yunhao , Du Kangjia , Sun Mengze , Zhang Hao , Tu Hongyuan , Jiang Xinrong , Lu Juan , Tu Lixue , Niu Yuqing , Chen Peng
Published: June 2023

Cancer is a significant health burden in the world. Natural product drugs have received widespread attention because of their safety and effectiveness, stable effects and fewer side effects. Some studies have demonstrated that exopolysaccharide (EPS) from lactic acid bacteria (LAB) can inhibit the growth of many types of cancer cells. In this work, the effects of the EPS from Lactiplantibacillus plantarum YT013 on gastric cancer cells were investigated. Its cytotoxicity was evaluated by MTT assay; at the concentration of 1000 μg/mL, the most significant inhibitory effect occurred in AGS cells, followed by SGC-7901, PANC-1 and HCT116, and less inhibited in HepG2 cells. Cell cycle results showed that EPS prevented AGS cells from transitioning from the S phase to the G2/M phase. In addition, the results of flow cytometry showed that EPS promoted apoptosis in a concentration-dependent manner. Western blotting also indicated that EPS might lead to apoptosis via the endogenous mitochondrial apoptotic pathway. The safety of lyophilized powder, cell-free culture supernatant and EPS from Lactiplantibacillus plantarum YT013 were evaluated by observing tissue organs through H&E staining, and the results showed that the components were safe and effective and could provide a basis for the development of natural anticancer active drugs.
Federated Learning and Blockchain Integration for Privacy Protection in the Internet of Things: Challenges and Solutions
Authors: Al Asqah Muneerah , Moulahi Tarek
Published: June 2023

The Internet of Things (IoT) compromises multiple devices connected via a network to perform numerous activities. The large amounts of raw user data handled by IoT operations have driven researchers and developers to provide guards against any malicious threats. Blockchain is a technology that can give connected nodes means of security, transparency, and distribution. IoT devices could guarantee data centralization and availability with shared ledger technology. Federated learning (FL) is a new type of decentralized machine learning (DML) where clients collaborate to train a model and share it privately with an aggregator node. The integration of Blockchain and FL enabled researchers to apply numerous techniques to hide the shared training parameters and protect their privacy. This study explores the application of this integration in different IoT environments, collectively referred to as the Internet of X (IoX). In this paper, we present a state-of-the-art review of federated learning and Blockchain and how they have been used in collaboration in the IoT ecosystem. We also review the existing security and privacy challenges that face the integration of federated learning and Blockchain in the distributed IoT environment. Furthermore, we discuss existing solutions for security and privacy by categorizing them based on the nature of the privacy-preservation mechanism. We believe that our paper will serve as a key reference for researchers interested in improving solutions based on mixing Blockchain and federated learning in the IoT environment while preserving privacy.
Food-Waste Valorisation: Synergistic Effects of Enabling Technologies and Eutectic Solvents on the Recovery of Bioactives from Violet Potato Peels
Authors: Grillo Giorgio , Tabasso Silvia , Capaldi Giorgio , Radosevic Kristina , Radojčić-Redovniković Ivana , Gunjević Veronika , Calcio Gaudino Emanuela , Cravotto Giancarlo
Published: June 2023

The recovery of valuable bioactive compounds from the main underutilised by-products of the food industry is one of the greatest challenges to be addressed in circular economy. Potato peels are the largest waste generated during potato processing. However, they could be a potential source of valuable bioactive compounds, such as polyphenols, that can be reused as natural antioxidants. Currently, environmentally benign enabling technologies and new types of non-toxic organic solvents for the extraction of bioactive compounds may dramatically improve the sustainability of these processes. This paper focuses on the potential inherent in the valorisation of violet potato peels (VPPs) by recovering antioxidants using natural deep eutectic solvents (NaDES) under ultrasound (US)- and microwave (MW)-assisted extraction. Both the enabling technologies provided performances that were superior to those of conventional extractions in terms of antioxidant activity determined by the DPPH· (2,2-diphenyl-1-picrylhydrazyl) assay. In particular, the most promising approach using NaDES is proven to be the acoustic cavitation with a Trolox eq. of 1874.0 mmolTE/gExtr (40 °C, 500 W, 30 min), vs. the 510.1 mmolTE/gExtr of hydroalcoholic extraction (80 °C, 4 h). The shelf-life of both hydroalcoholic and NaDES-VPPs extracts have been assessed over a period of 24 months, and found that NaDES granted a 5.6-fold shelf-life extension. Finally, the antiproliferative activity of both hydroalcoholic and NaDES-VPPs extracts was evaluated in vitro using the MTS assay on human tumour Caco-2 cells and normal human keratinocyte cells (HaCaT). In particular, NaDES-VPPs extracts exhibited a significantly more pronounced antiproliferative activity compared to the ethanolic extracts without a noteworthy difference between effects on the two cell lines.
IoT-Enabled Electronic Nose System for Beef Quality Monitoring and Spoilage Detection
Authors: Damdam Asrar Nabil , Ozay Levent Osman , Ozcan Cagri Kaan , Alzahrani Ashwaq , Helabi Raghad , Salama Kahled Nabil
Published: June 2023

Food spoilage is a major concern in the food industry, especially for highly perishable foods such as beef. In this paper, we present a versatile Internet of Things (IoT)-enabled electronic nose system to monitor food quality by evaluating the concentrations of volatile organic compounds (VOCs). The IoT system consists mainly of an electronic nose, temperature/humidity sensors, and an ESP32-S3 microcontroller to send the sensors’ data to the server. The electronic nose consists of a carbon dioxide gas sensor, an ammonia gas sensor, and an ethylene gas sensor. This paper’s primary focus is to use the system for identifying beef spoilage. Hence, the system performance was examined on four beef samples stored at different temperatures: two at 4 °C and two at 21 °C. Microbial population quantifications of aerobic bacteria, Lactic Acid Bacteria (LAB), and Pseudomonas spp., in addition to pH measurements, were conducted to evaluate the beef quality during a period of 7 days to identify the VOCs concentrations that are associated with raw beef spoilage. The spoilage concentrations that were identified using the carbon dioxide, ammonia, and ethylene sensors were 552 ppm–4751 ppm, 6 ppm–8 ppm, and 18.4 ppm–21.1 ppm, respectively, as determined using a 500 mL gas sensing chamber. Statistical analysis was conducted to correlate the bacterial growth with the VOCs production, where it was found that aerobic bacteria and Pseudomonas spp. are responsible for most of the VOCs production in raw beef.