bluuebunny/crossref_metadata_2025 huggingface dataset:
An Analysis of the Requirements for a Sustainable Lunar Transportation System to Enable Initial DIANA Infrastructure
Authors: Acker Denis , Gutierrez Elizabeth , Calatayud Javier Palacios , Modi Prishit , Kugic Alma , Khan Sajeel
Published: June 2023

The Dedicated Infrastructure and Architecture for Near-Earth Astronautics (DIANA) is a design concept for a self-sustainable lunar village near the de Gerlache crater, on the lunar South Pole, comprising tourists and astronauts alike. The village will be permanently inhabited and will exploit future technologies to achieve independence from a majority of Earth resupply missions. Execution of the initial construction phase of the DIANA infrastructure depends primarily on the persistent supply of in-situ construction material, regolith. Lunar raw materials also primarily contribute to the life support systems (LSS) and the radiation protection for the inhabited modules. To enable ISRU, resources need to be transported using diverse locomotion systems on the unexplored lunar terrain. A self-sustainable lunar base requires to be built on an ecosystem that facilitates continuous transportation of materials, humans (astronauts and tourists) and robotic systems. This paper focuses on a detailed comprehension of the design, feasibility, and economic requirements of a transportation ecosystem concept explicitly dedicated to the establishment and development of the DIANA lunar village. The mission objectives and top level requirements pertaining to the individual transportation systems will be derived from the detected necessities that are defined for alternative transportation technologies that efficiently provide large amounts of lunar raw material for the construction of lunar infrastructure as well as water ice from the de Gerlache Crater, which shall primarily contribute to the LSS and the production of rocket fuel. While transporting humans, factors such as time, comfort, and risk mitigation play a major role, and are therefore, discussed thoroughly within the framework of this study. Using this study as the principal foundation, a phase 0/A design study illustrating a novel transportation infrastructure concept based on magnetic levitation technology would be developed for efficient transportation of resources and people across the lunar surface. This transportation concept shall be sustainably manufactured using the abundant lunar resources to minimize costs and resupply missions in the long term to pave the way for an independent lunar village.
Structural efficiency evaluation of innovative reusable launch vehicles
Authors: Trifa Panagiotis , Rellakis Dimitrios , Psoni Georgia
Published: June 2023

This work is focused on evaluating the structural design of the innovative reusable micro launcher MESO, originated from the RRTB, a funded project by EU. The structural efficiency of MESO is evaluated in association with its mass budget, which is based on project’s early adopted requirements. In this particular design loop, the reusability concept is intergraded by implementing the fail-safe design approach, considering the exclusive use of high TRL aluminum alloys. The main objective of this work is achieved by developing a global Finite Element Model (FEM), comprising a set of sub-models, which represent the primary structure, the secondary structures, the equipment and their interfaces as well.

The paper proceeds with the description of the modelling approach regarding mesh development and the connections created between the sub-models for assembling the integrated Global FEM of the launcher. The first iteration of the load analysis loop resulted in the extraction of the Design Limit Loads (DLL). The DLL investigated in both ground and flight cases, which comprise the most severe combination of quasi-static loads. The FEM is verified and subjected to various types of preliminary structural analysis, taking into consideration the required ECSS design and safety factors for static strength and stability assessment.

The analyses results indicated the order of magnitude and the location of all weak areas of the launcher. Subsequently a preliminary sizing procedure is performed in order to prevent all failure modes according to the structural design requirements. The conclusions derived from the structural analysis of the first design loop influence the design modifications to be considered for the next design loop, where the same steps are going to be followed until the structural design requirements are satisfied once again.
Iterative design development of a reusable micro-launcher within the RRTB project
Authors: Bergström Rasmus , Pilori Daniele , Pinheiro Miguel , Zamprotta Alessandro , Medici Giovanni , Trovarelli Federico , Oton Raquel Marey
Published: June 2023

The Recovery and Return-To-Base European Reusable Micro-Launcher project, part of the European Commission’s H2020 programme, intends to develop a novel reusable micro launcher system to bring independent and cost-effective access-to-space for the European small satellite market. The multi-disciplinary project focuses on the optimization of aerospike tail-first atmospheric re-entry of the MESO vehicle, together with the design and manufacturing of reusable cryogenic tanks, and the effort is divided into two design loops, where each design loop starts from establishing early design decisions and assumptions so that dedicated subsystem work may progress immediately. The multiple design loop approach allows for unsuitable design decisions, or risky and speculative assumptions to be revised or excluded at the project half-way point, thereby acting as a form of risk management. Throughout the work performed in the first design loop several conclusions were reached. The design presented both novel design features, but also critical issues which became better understood as the fidelity of the subsystem designs and mission analysis increased. These issues ultimately lead to the overall system design and CONOPS to be updated for the second loop, with several of the early design choices being modified, especially through the removal of the EDF landing system, based on the results of the first loop. For the second design loop, the design is updated to alleviate the most critical problem drivers, and to improve the system’s ability to fulfil the top-level requirements and objectives. The updated design uses a Mid-Air Catch approach, and leverages on the heritage of the previous design loop, implementing tailored changes based on the outcome of the trade-offs performed at mission and system levels.
Breadboard of Microchip and Avalanche Photodiode in Linear and Geiger Mode for LiDAR Applications
Authors: Sousa Ana , Pinto Rafael , Couto Bruno , Nadal Beltran , Onderwater Hugo , Gordo Paulo , Abreu Manuel , Melicio Rui , Michel Patrick
Published: June 2023

This paper reports the implementation of two critical technologies used in LiDARs: 1) A microchip Q-switched laser breadboard and 2) breadboard of an Indium gallium arsenide avalanche photodiode working at 300 K with high reverse polarization voltages. Microchip Q-switched lasers are small solid state back pumped lasers, that can generate high energy short pulses. The implemented breadboard used an Erbium and Ytterbium co doped phosphate glass, a COMALO crystal with 98% (initial transparency) and an output coupler of 98% reflectivity. For the sensor test, a system for the simultaneous operation in vacuum and wide range of temperatures was developed. Avalanche photodiodes are reverse polarized photodiodes with high internal gain, due to their multiple layer composition, capable of building up high values of photocurrent from small optical signals by exploiting the avalanche breakdown effects. The test avalanche photodetector was assembled to be operated in two modes: Linear and Geiger mode, to achieve this behavior, a transimpedance amplifier circuit was implemented. These two technologies are critical for mobile LiDAR applications, due to its low mass and high efficiency. The paper describes the breadboard implementation method and sensor characterization at low temperature and high voltage (beyond breakdown voltage).
Satellite Star Tracker Breadboard with Space Debris Detection Capability for LEO
Authors: Filho Joel , Gordo Paulo , Peixinho Nuno , Gafeira Ricardo , Melicio Rui , Silva André
Published: June 2023

This paper evaluates the possibility of having a star tracker device running space debris algorithms. A simple star tracker breadboard was developed to evaluate the possibility of having a device running both stellar identification and space debris algorithms. The breadboard was built with commercial off-the-shelf components, representing the current star tracker resolution and field of view. A star tracker device and space debris algorithms were implemented and tested, respectively: Tetra and ASTRiDE. The device concept was tested by taking pictures of the night sky with satellite streaks. Seeking to overcome such limitations, a dual-purpose star tracker with stars detection and optical debris detection capability is proposed. Star trackers are usually used in satellites for attitude determination and therefore have a vast potential to be a major tool for space debris detection. The rapid increase of space debris poses a risk to space activities, so it is vital to detect it. Ground-based radar and optical telescope techniques used for debris detection are limited by a size threshold, detecting only a tiny amount of the total, reason why evaluating the possibility of detecting them in space is of major importance.
The design of a flexible RF generator for driving Acousto-Optical devices in space applications
Authors: Vanhamel J , Stutman D
Published: June 2023

Acousto-Optical (AO) devices are not only used for filtering purposes in spectral imaging, but also in optical communications and spatial tracking systems. Some AO devices with space applications are AO Tunable Filters (AOTFs), Modulators (AOMs), Deflectors (AODs) and Frequency Shifters (AOFSs). Though these device’s applications differ, they are all controlled with Radio-Frequency (RF) signals. These signals are converted by a transducer into an acoustic wave, which propagates inside the AO device. The interaction between the incoming light and the acoustic waves inside the birefringent AO material creates multiple output beams. This interaction can result in filtering, modulation, deflection or frequency shifting, depending on the AO device in question. This research focuses on the design of a flexible, uniform RF generator, applicable to all AO devices in the space applications domain. The RF output maximizes the performance of the AO device, while the use of components available in space qualified grades eases integration with future space missions. Its design is a key step towards a miniaturized, space qualified, general-purpose RF generator. This research presents schematics, design and preliminary component test results.
Outcomes of the PERIOD project on In-Space Manufacturing, Assembly and Refuelling Technologies
Authors: Estable Stéphane , Ahrns Ingo , Regele Ralf , Jankovic Marko , Brinkmann Wiebke , Gancet Jeremi , Barrio A. M. , Leiter Pierre , Colmenero Francisco J. , Ampe Annelies , Ordoubadian Björn , Chamos Apostolos , Caujolle Romain , Silveira Daniel , Soto Isabel , Shilton Mark , Vogel Torsten , Bartsch Sebastian , Manz Marc
Published: June 2023

Traditionally, satellites and other space-specific assemblies (e.g., antennas, spacecraft, etc.) are built on Earth and then sent into orbit. New approaches are pursuing direct on-orbit manufacturing and assembly using robotics, autonomy, and modularity. The advantages are many, ranging from virtually unlimited overall volume and design of large satellite antennas to numerous options for building larger space infrastructures such as large reflectors and modular space stations. In addition, in-space manufacturing and assembly (ISMA) technologies can enable the upgrade and repair of existing spacecraft and satellites already in orbit, promoting the sustainable use of space through plug-and-play modularity. The PERIOD project is pursuing a concept in which an orbital demonstrator is being developed for satellite manufacturing and assembly, as well as docking and refuelling experiments. This paper describes the background of the development, the PERASPERA building block technologies ESROCOS (European Space Robotics Control and Operating System), ERGO (European Robotic Goal-Oriented Autonomous Controller) and InFuse (Data Fusion) used, the test setup of the demonstrator and first results. The successful implementation and validation of ISMA technologies will lead to the generation of independent European capacities allowing Europe to build future orbital infrastructure and to be competitive on the ISMA markets
Continuing education in green chemical processes for aerospace manufacturing: The case of drag-out
Authors: Aptoglou M. , Papachristodoulou S. , Gounaris N. , Peta D. , Vourdas N.
Published: June 2023

In the new era of job market in the EU zone and abroad, novel Occupational Profiles dictate the development and the update of Learning Outcome-based Curricula. This stands for all disciplines and specialties and for various Qualification Levels (QL), from after-school education up to the highest QL. The pertaining Curricula should allude to specific knowledge, skills, and behaviours, that are being mandated from the respective Occupational Profiles. For intermediate QL, namely in between secondary school and University, there is an utmost need for new, updated, attractive Curricula covering current and new market needs. Such Curricula should be supported from Course Units that are technologically updated, thus providing the trainees the skills and knowledge to cover the current and novel Learning Outcomes and Performance Criteria for the specified QL. We herein present a newly developed Course Unit, part of the Green Special Processes course that can be offered in the context of a continuing Vocational Education Training (cVET) Program targeting a QL equivalent to the European QL 5. This Course Unit covers the case of drag-out, which has significant environmental and economic impacts on the engineering of wet chemical processes entailing multiple process baths and requiring rinsing. Such processes are widely used also in Aircraft manufacturing and the related environmental impacts have become very important. Part of the basic theory, as well as part of the practical training are presented herein.
Energy management strategy of field power station based on differential hysteresis voltage stabilization
Authors: Wang Haisheng
Published: June 2023

The existing field power stations mainly use diesel generator sets for power supply, with poor power supply stability and no uninterrupted power supply capability. Therefore, a hybrid energy storage device is introduced into the field power station to improve it. According to the working characteristics of different energy sources, an energy management strategy based on differential hysteresis voltage stabilization is proposed. Hysteresis voltage stabilization control makes it true that the diesel generator set as the main energy source works for a long time, and the battery as a backup energy source works when necessary. Differential voltage stabilization control realizes coordination control of the two, which allows the battery to exit work smoothly. The strategy can get transient stability and stable economy, and extend the life of the battery. Simulation results show that this strategy is superior to the traditional hysteresis voltage stabilization strategy.
Anti-interference Performance of the Temperature Acquisition System for the Vacuum Thermal Test
Authors: Wen Jing , Feng Yao , Wu Dongliang , Zhu Xi , Liao Tao , Shen Bin
Published: June 2023

The thermal test temperature acquisition system is one of the core systems in the thermal test of the spacecraft. It uses thermocouple sensors for temperature data acquisition, and its data stability directly affects the success or failure of the thermal test task. The equipment types in the original thermal test environment were single, and the electromagnetic compatibility design was weak. With the increase of the types of test equipment in the thermal test, the electromagnetic interference in the test environment is becoming more and more serious and even directly affects the stability of temperature data collection. Based on the principle of thermocouple temperature measurement and electromagnetic compatibility, this paper establishes relevant models for analysis and simulation and obtains methods to improve system electromagnetic compatibility under different interference conditions. And in a certain thermal test, using the simulation results of the model, the corresponding circuit improvement was carried out, which finally reduced the influence of electromagnetic interference on the system and ensured the smooth progress of the task.
Fault Section Location Method for Distribution Network Based on Waveform Difference Clustering
Authors: Luo Hanjing
Published: June 2023

The conditions of single-phase grounding faults are variable in the resonant grounded system, and the traditional fault location methods of the distribution system based on a single characteristic quantity have their own discrimination blind area, and the reliability of the method is difficult to guarantee. In order not to be troubled by the problems, a fault section location method based on waveform difference degree clustering is proposed. According to the differential characteristics of transient and steady component waveforms of zero-sequence current at each detection point upstream and downstream of a fault point, the discrete Fréchet distance algorithm is used to quantify the transient waveform difference and steady-state waveform difference between adjacent detection points, and Fuzzy C-Means algorithm (FCM) is used to synthesize multi-feature information to distinguish the normal section from the fault section, which effectively eliminates the single feature location blind area and realizes adaptive fault section location. The PSCAD/EMTDC simulation results show the method is suitable for accurate location under different fault conditions.
Calcium carbide furnace batching system based on integral separation PID control
Authors: Zhou Dedong , Shi Dongdong
Published: June 2023

The precise ratio of raw materials and the uniformity of furnace charge mixing are the premise of calcium carbide quality, energy saving, and consumption reduction, which have a great influence on the operation of calcium carbide furnaces. Based on analyzing the batching equipment and the batching process, the mathematical model of the batching process is established and the model parameters are determined by the method of the soaring curve. According to the characteristics of the batching process, a quantitative feeding control system was designed by using an integral separation PID control algorithm, and PID controller parameters were determined by the empirical trial and error method. The practical application in the production field shows that the quantitative feeding control system designed in this paper can fully meet the precise ratio of raw materials and the uniformity of mixing charge of calcium carbide furnace.
Energy Efficiency Evaluation Method for Township Power Users Based on OLAP Technology
Authors: Yin Yucan
Published: June 2023

With the development of the smart grid and energy Internet, the traditional demand side response is further expanded to the integrated energy management of users, which puts forward higher requirements for the energy management level of users. The energy consumption structure of users has changed greatly. How to measure the rationality of energy consumption, reduce the cost of energy consumption, save energy, and improve efficiency is very important for users. Aiming at the energy efficiency evaluation of township power users, this paper constructs an index system including users’ energy utilization. It also establishes an evaluation method based on the NSGA-III algorithm combined with OLAP technology to measure the closeness between each energy use scheme and the optimal energy use scheme. Finally, through the example analysis and verification, the results indicate that the proposed energy efficiency evaluation method based on OLAP technology is reasonable. Energy efficiency evaluation can meet the needs of information interaction between users and the smart grid, and improve the energy efficiency and energy-saving effect of township power users through energy efficiency evaluation and management.
Control Technology of Smart Grid Considering Intermittent Power Uncertain Dispatch
Authors: Liao Feng , Lu Ying
Published: June 2023

The phenomenon of “anti-peak regulation” occurs when large-scale new energy is connected to the grid. The strange phenomenon of wind, light, and water curtailment at low loads occurs in areas with weak power regulation capacity, and the problem of peak regulation of the power system has become increasingly prominent. The typical scenario method is adopted to simplify the description of photovoltaic power generation output and hydropower station runoff. Then, considering the fluctuation of power production and output of the water and photovoltaic complementary system, the short-term multi-objective optimal dispatching model of the water and the photovoltaic complementary system is constructed with the objective of maximizing the average capacity coefficient and power generation load rate of the system on the premise of meeting the corresponding hydropower constraints. Finally, the simulation experimental platform is built. The multi-objective algorithm is used to solve the model. Through the case study, the complementary effect of intermittent power uncertain dispatching is analyzed, and the effectiveness of the model is verified. The dispatching mode can fully guarantee the collaborative optimization decision-making problem of a multi-microgrid with clean power. It can also effectively promote the acceptance level of clean power in the distribution network, and reduce the carbon emission of the distribution network.
Planning and Design of Building Electricity Based on Spatial Distribution Model
Authors: Li Youhua
Published: June 2023

Electrical equipment is ubiquitous in modern buildings, which not only provides great convenience but also produces a lot of energy consumption, which is contrary to the current purpose of energy saving and emission reduction. Under this background, the planning and design of building electricity based on a spatial distribution model are studied. In this study, BIM software is applied to build a building spatial distribution model. On this basis, the power supply and distribution system is re-planned, including the reasonable selection of transformer specifications and models, the selection and laying of cable conductors, and the improvement of the power factor. With the minimum energy consumption as the planning objective, the genetic algorithm is adopted to plan the operation scheme of the lighting electrical system and HVAC electrical system. The results verify that, according to the building electrical planning scheme based on the spatial distribution model, the energy consumption of the building is less in 15 hours, which illustrates the rationality of the planning scheme.
Path Following for UAV using Nonlinear Model Predictive Control
Authors: Chen Chao , Tan Jiali
Published: June 2023

For the fixed-wing UAV control system, the lateral path-following system is an important part, which ensures that the UAV flies stably in accordance with the predetermined route within a certain height. For the lateral path following of UAV based on nonlinear model predictive control, the model of the lateral kinematics of the fixed-wing UAV is established first, and then the path-following problem of UAV at a constant height is considered. The objective function with constraints based on the NMPC is established, and finally the nonlinear optimization algorithm is used to minimize the designed objective function. The optimal control quantity in the rolling interval is obtained. Matlab is used to simulate the designed controller and compare it with the commonly used L1 guidance law, and the results of the simulation demonstrate that the NMPC has superior control leverage.
A Weighting-Factorless Predictive Torque Control Method for Open-End Winding PMSM with Common DC Bus
Authors: Zhang Dongdong , Yu Junyong , Du Annan , Lin Xiaogang
Published: June 2023

The weighting factors (WFs) of conventional predictive torque control (PTC) are difficult to tune, which limits its practical application. When the conventional PTC is applied to the open-end winding permanent magnet synchronous motor (OEW-PMSM) with a common DC bus, there are three different units of variables that require prediction and control. Therefore, it is necessary to introduce two WFs to construct the cost function (CF), which increases the difficulty of realizing the control strategy. Sequential PTC adopts the idea of hierarchical optimization to avoid the introduction of WFs directly. In this paper, the sequential PTC structure is constructed to avoid the introduction of WFs. Then, the number of elements in the finite control set (FCS) of each layer is optimized to reduce torque and zero sequences current (ZSC) ripple, so as to achieve a better control effect. Finally, the effectiveness of the proposed sequential control strategy is proved by simulation.
FBG temperature measurement error compensation method based on LSTM and attention mechanism
Authors: Chen Yannan , Li Haitao , Kong Weiheng , Wang Lihui
Published: June 2023

Real-time temperature measurement of power cables is an important part of the power system, and improving the accuracy of temperature measurement is a key factor of the temperature measurement system. The measurement of existing measurement methods is susceptible to interference and has certain errors. In this paper, an error compensation model is established by using a two-layer LSTM network to view the dynamic error in the process of FBG temperature measurement, and the attention mechanism is used to capture the relevant parameters of temperature change, so as to improve the model effect. The experimental results show that the compensation effect of the two-layer LSTM-Focus model is increased by 44.4% compared with the single LSTM model, which can meet the actual measurement requirements.
Fault Traveling Wave Detection Method based on ICEEMDAN-MCKD
Authors: Zeng Jiachen , Ni Cong , Yu Kun
Published: June 2023

To address the challenge of calibrating the traveling wave-front for fault location in high noise environments, we propose an improved method that combines the ICEEMDAN and maximum correlation kurtosis deconvolution (MCKD). Our approach first decomposes the fault traveling wave signal into modal components using the ICEEMDAN algorithm. Next, the MCKD algorithm enhances the energy amplitude of the decomposed signal, suppresses strong background noise interference, and accurately calibrates the fault traveling wave-front. Simulation results demonstrate that ICEEMDAN-MCKD achieves precise calibration of the wave-front, exhibits strong denoising ability, and performs better than existing methods in terms of detecting traveling waves and minimizing wave-front determination time errors in noisy environments.
Ventilation and heat dissipation analysis of photovoltaic roof
Authors: Yin Zirui , Zhang Tao , Cai Jingyong , Fan Yi , Shi Zhengrong
Published: June 2023

In recent years, the development and utilization of new energy have attracted more and more attention. As a green and clean energy, the utilization and development of solar energy have attracted much attention. Moreover, solar photovoltaic (PV) technology has been vigorously promoted, with building-integrated photovoltaic (BIPV) technology widely used in the building sector. However, in BIPV, although PV modules can be used as building envelope materials and provide electricity for buildings, due to various conditions during installation and design, PV modules are prone to overheating problems and affect photovoltaic performance. Hence, in the present study, a novel type of PV roof structure with lightweight crystalline silicon PV modules installed on the building surface is proposed, and an air space is provided between the novel lightweight crystalline silicon PV modules and the building surface, the novel lightweight crystalline silicon PV module has the characteristics of thinness and flexibility. After that, an experimental test platform with air space is established, and the data of typical meteorological days are selected to analyze the electrothermal performance of the novel lightweight PV roof, to obtain the optimal structure with the best PV performance. The results show that, under the same conditions, when the spacing is 0 mm and 80 mm, the temperature of the backplane and the substrate of the PV module gradually decreases with the increase of the air space. In contrast, the PV power and electricity generation gradually increase with the growth of the spacing. At the same time, when the distance exceeds 40 mm, the changing trend of the backplane of the PV module temperature, the temperature of the roof substrate, and the electricity generation is not apparent. In the present study, the optimal spacing of the novel lightweight PV roof is 40 mm.
Experimental study and simulation of distributed photovoltaic heating asphalt system
Authors: Zhai Shuncai , Qing Chunyao , Wang Zhenzhong , Kong Lingchen , Liu Chunyu , Liu Shengyong
Published: June 2023

The traditional asphalt heating methods need to consume many fossil fuels, which conflicts with carbon peaking goals and neutrality. Therefore, replacing fossil fuels and improving heating efficiency is a realistic and severe task. This paper proposes a distributed photovoltaic heating asphalt system based on a literature review and field investigation of current asphalt mixing plants. The system rationally uses idle workshop roofs to lay solar photovoltaic modules for power supply. It replaces the natural gas boiler, heat conduction oil furnace, and asphalt heating tank with an integrated electric heating asphalt tank. The power generation capacity of the distributed photovoltaic power system and the electric heating asphalt heating process were tested and simulated, and the heat transfer characteristics of asphalt during heating were obtained. The results show that the daily generating capacity of the 39.6kW photovoltaic system is 135.8kWh, which can meet the heating demand of 3 tons of asphalt. The average asphalt heating rate increases to 19°C/h compared to the traditional heating rate. And no pollutants are produced during the whole process. Overall, the system can achieve remarkable efficiency improvement, energy conservation, and environmental protection.
Application of SAGD technology in the development of super heavy oil reservoir buried medium deep
Authors: Li Yujun
Published: June 2023

Continental super heavy oil reservoirs in China are characterized by deep burial depth, strong reservoir heterogeneity and high oil viscosity. The steam huff and puff technology are used to develop this type of reservoir, but in this development method, its oil recovery rate, oil steam ratio, and ultimate recovery are low. The benefit of the reservoir development is losses in this high cost per ton of oil. Many vertical wells injecting steam and one horizontal well-producing liquids pattern of SAGD technology (abbreviated as VERTIHORIONATAL pattern SAGD) were Innovated to solve the problems based on SAGD technology introduced from Canada. The SAGD technology introduced in Canada was made of double horizontal wells. The above horizontal well injects steam and the other horizontal well produces liquids continued (abbreviated as DOUBLE HORIZONTAL pattern SAGD). The VERTIHORIONATAL SAGD technology makes full use of the original well pattern of huff and puff and takes advantage of the thermal connectivity and underground temperature field formed by early development; At the same time, the VERTIHORIONATAL pattern SAGD technology can effectively solve the problem of steam cavity uneven expansion caused by reservoir heterogeneity by adjusting the location of steam injection vertical wells. It can also balance the liquid production in good horizontal sections and improve steam cavity formation speed by adjusting steam injection well sections and steam injection parameters. The technology has been successfully applied in the medium-deep super heavy oil reservoir in the Shu-1 area, Du84 block, Liaohe Oilfield. Seven oil wells with a daily output of 100 tons have been cultivated, and a stable production of million tons for four consecutive years. It has been built as China’s largest SAGD development demonstration area for medium-deep super-heavy oil.
Numerical Simulation of Flow Characteristics in Circulating Fluidized Bed Boiler
Authors: Zhao Bo , Yang Min , Cui Xutong , Bai Bingbing , Huang Fei , Gao Wanliang , Wang Lin
Published: June 2023

Considering the different particle sizes in the circulating fluidized bed boiler furnace, the binary-component method is used to analyze the flow characteristics in the circulating fluidized bed boiler furnace. The particle dynamics principle is used to solve the gas-solid two-phase mass equation, momentum equation and turbulence equation using the two-fluid model. The model uses more mature boiler design drawings, reproduces the flow characteristics of particles in the furnace, obtains the shape of the lower bubbling bed and the fast upper bed, and analyses the gas phase velocity and particle distribution in the furnace under the design parameters.
Numerical simulation on the re-injection capacity of drainage water in Area H of E gas field
Authors: Liu Chang-sheng , Si Lei-ting , Yu Wen-hua , Tian Hao-nian , Qin Yan , Zhang Ling-yun
Published: June 2023

The E gas field is a typical dense sandstone gas reservoir. It faces the problem of sewage treatment during production and development due to the influence of water formation. The H area with weak production capacity is selected for sewage re-injection and evaluating its re-injection capacity is a significant step before sewage treatment. In this paper, geological modeling and numerical simulation are carried out to evaluate the re-injection of the drainage water in Area H of the East E gas field, to maximize the amount of water injection within the acceptable range of the reservoir, and to analyze the leakage simulation of the two main possible leaky layers. The results show that: the formation rupture pressure in the study area is 42 MPa; the injection flow rate should be controlled at 60-80 m3/d, and the recommended injection wellhead pressure is 16-20 MPa; the leakage problem in He 7 sections should be considered in the subsequent wastewater re-injection.
Wind Power Interval Prediction Based on Robust Kernel Density Estimation
Authors: Xie Daiyu , Fu Yuan , Yang Sheng , Yang Youhui , Chen Mingyuan
Published: June 2023

Wind power output has a high degree of randomness, so it is difficult to describe it accurately with some typical probability distribution. The extreme values influence the sample’s general non-parametric kernel density estimation method, and the estimated results are relatively conservative. A wind power interval prediction method based on robust kernel density estimation is proposed to improve the compactness and accuracy of interval prediction. In probability estimation, this method will assign a small weight to the extreme sample data to reduce its influence on the probability density estimation accuracy and has better robustness than the general kernel density estimation method. In addition, the bandwidth of robust kernel density estimation is a dynamic parameter, which can be adjusted with the sample data to improve the prediction accuracy and avoid over-conservative prediction.
Influence of plasma parameters on the effectiveness of multi-cusp magnetic field confinement in negative ion sources
Authors: Candeloro V. , Sartori E. , Serianni G.
Published: June 2023

Cusp-shaped magnetic fields are widely used to confine plasmas in various
applications. This field configuration allows to localise plasma losses: the width of such loss
cone, usually called leak width, was found to be proportional to the geometric mean of the ion and
electron Larmor radii, so that it becomes smaller for increasing magnetic field intensity. At the
same time, plasma diffusion towards the walls is reduced in the regions where the field lines are
parallel to the surfaces, leading to the formation of a Plasma Exclusion Zone (PEZ) whose
characteristic dimension was found to be proportional to the distance between the magnets. Besides
field intensity and geometry, the confinement effectiveness might also be affected by plasma
properties such as electron temperature, plasma potential across the sheath and
collisionality. Specifically, this contribution describes a numerical analysis performed by means
of a 2D-3V Particle-In-Cell code of the dependencies of both the PEZ size and the leak width on
magnetic field intensity and plasma potential, focusing on typical conditions found in plasma
sources for negative ion beams. The leak width was found to be larger than its theoretical
prediction regardless of the specific plasma parameters. The PEZ was found to be affected not only
by the distance between the magnets. In particular, the plasma potential was found to strongly
affect the plasma behaviour within the cusp region.
Satellite data reveal how Sudd wetland dynamics are linked with globally-significant methane emissions
Authors: Hardy Andy , Palmer Paul I , Oakes Gregory
Published: June 2023

Recent work has highlighted the large role of methane emissions from the Sudd wetland and surrounding ecosystems on the global atmospheric growth rate of methane since 2010. These emissions are driven by high rainfall over basin catchments linked with the positive phase of the Indian Ocean Dipole. We reconstruct flood inundation for the Sudd wetland over a 38-year period at a spatial resolution of 30 m using a new satellite Earth Observation (EO) wetland mapping tool. We reveal considerable changes in the wet season extent of the wetland, including an increase >300% since 2019 compared to the median 1984–2022 extent. We report major increases in flood extent within grassland-dominated floodplains outside of the area currently defined Sudd wetland region. These year-to-year changes in wetland extent are corroborated with total water storage anomalies inferred from satellite data (Pearson correlation R = 0.92), Lake Victoria levels (R = 0.73), and anomalies in reported annual mean global methane growth rates since 2009 (R = 0.88). Our analysis shows that flood water inundation is dominated by inundated vegetation and aquatic vegetation, accounting for an average of 40% and 50% of total extent, respectively, compared to open water that accounted for just 9% of inundation in a typical year. This is consistent with recent studies that report wetland methane emissions are focused on areas with inundated vegetation. Our findings also support recent studies that highlight the significant role of the Sudd wetland in driving anomalously large global atmospheric annual growth rates, 2020–2022. By capturing high resolution information on inundated vegetation, our EO wetland mapping tool has significant potential for improved wetland emission estimates of methane. Vascular plants common in the Sudd wetland, e.g. macrophytes including Phragmites Australis and Cyperus Papyrus, seem to play a key role in methane emissions and we recommend they should be the focus of future research.
The impacts of temperature averages, variabilities and extremes on China’s winter wheat yield and its changing rate
Authors: Yu Yueyue , Yang Xuhui , Guan Zhaoyong , Zhang Qi , Li Xichen , Gul Chaman , Xia Xin
Published: June 2023

China is the world’s largest producer and consumer of wheat. The impact of temperature averages, variabilities, and extremes on winter wheat yield changes is still not very clear. The annual production data for winter wheat in China’s provinces and municipalities and NCEP-NCAR Reanalysis-1 data were used from November to April in the period 1949–2018, to investigate the impact of temperature-related variables, such as the winter average temperature (

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), winter variance of temperature (

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), extreme hot days (EHD), and extreme cold days (ECD), on China’s winter wheat yield. Ensemble Empirical Mode Decomposition (EEMD) analysis showed that winter wheat yield has an in-phase relationship with average temperature but an out-of-phase relationship with variance of temperature, extreme hot days, and extreme cold days on timescales greater than 20 years. The changing rates of winter wheat yield and temperature-related variables were well measured by their sliding trends. At the overwintering growth stage, the increasing rate of average temperature and extreme hot days (temperature variance and extreme cold days) exhibit negative (positive) correlations with the rate of winter wheat yield change, with the strongest correlation observed in southeast China. During the tillering growth stage, the changing rates of average temperature exhibited a positive correlation with the rate of winter wheat yield change, whereas negative associations were observed with temperature variance, extreme hot days, and extreme cold days. Among the regions, Central China showed the weakest correlations. At the reviving growth stage, however, the relationship of changing rates of temperature-related variables with that of winter wheat yield was much weaker. These observational results are important and can be used as a reference in climate models for improving the climatic impacts on the winter wheat yield.
The Importance of Lay Summaries for Improving Science Communication
Authors: Goldstein Carly M , Krukowski Rebecca A
Published: June 2023

Lay summaries help the public connect with your research. Communicate your science with these guidelines for crafting lay summaries
Neuroimaging prognostic factors for treatment response to motor imagery training after stroke
Authors: Zhang Kexu , Wang Hewei , Wang Xu , Xiong Xin , Tong Shanbao , Sun Changhui , Zhu Bing , Xu Yiming , Fan Mingxia , Sun Limin , Guo Xiaoli
Published: June 2023

The efficacy of motor imagery training for motor recovery is well acknowledged, but with substantial inter-individual variability in stroke patients. To help optimize motor imagery training therapy plans and screen suitable patients, this study aimed to explore neuroimaging biomarkers explaining variability in treatment response. Thirty-nine stroke patients were randomized to a motor imagery training group (n = 22, received a combination of conventional rehabilitation therapy and motor imagery training) and a control group (n = 17, received conventional rehabilitation therapy and health education) for 4 weeks of interventions. Their demography and clinical information, brain lesion from structural MRI, spontaneous brain activity and connectivity from rest fMRI, and sensorimotor brain activation from passive motor task fMRI were acquired to identify prognostic factors. We found that the variability of outcomes from sole conventional rehabilitation therapy could be explained by the reserved sensorimotor neural function, whereas the variability of outcomes from motor imagery training + conventional rehabilitation therapy was related to the spontaneous activity in the ipsilesional inferior parietal lobule and the local connectivity in the contralesional supplementary motor area. The results suggest that additional motor imagery training treatment is also efficient for severe patients with damaged sensorimotor neural function, but might be more effective for patients with impaired motor planning and reserved motor imagery.
Strategic Competition and US–China Relations: A Conceptual Analysis
Authors: Winkler Stephanie Christine
Published: June 2023

Despite much attention on “strategic competition” between the USA and China following the declaration of China as America’s “strategic competitor,” the concept’s meanings, origins, as well as different analytical and political functions remain poorly understood. The present article fills this lacuna by conducting a conceptual study of “strategic competition” that traces the concept and its evolution over time. The article finds that there was never a singular or universally applicable meaning of “strategic competition”. When the concept first appeared during the détente era, politicians and scholars referred to the reality of needing to curtail “strategic competition” between the USA and the Soviet Union, and seek cooperative relations, such as through arms reduction treaties. In the late 1990s, the label “strategic competitor” became central to political efforts by the Bush administration to justify their pursuit of military power, deterrence, and American hegemony. Since the Trump administration in the late 2010s, “strategic competition” became a goal to pursue in US-China relations rather than something to be managed. Not recognizing the historical evolution of the term and its many different variations is analytically poor and politically dangerous, and impedes the development of a modus vivendi between the two great powers.
A Concept Forensic Methodology For The Investigation Of IoT Cyberincidents
Authors: Castelo Gómez Juan Manuel , Carrillo-Mondéjar Javier , Roldán-Gómez José , Martínez Martínez José Luis
Published: June 2023

The number of Internet of Things (IoT) forensic investigations has increased considerably over recent years due to the weak nature of the security measures of its devices. In order to ensure the effectiveness and completeness of their examinations, investigators rely on forensic models, frameworks and methodologies. However, given the novelty of the environment, the existing ones are not refined enough, and the conventional counterparts do not satisfy the requirements of the IoT. Consequently, further improvements are needed in order for a more suitable IoT methodology to be designed. After reviewing the proposals from the research community for the development of procedures for performing IoT investigations, this article presents a practical concept methodology for conducting IoT forensic investigations that details step by step the whole examination process from its opening to its closing. In order to test its effectiveness and feasibility, it is submitted to a theoretical, a practical and a hybrid evaluation. Firstly, by comparing its level of detail, practicality and content with the related work. Secondly, by assessing its performance in two practical scenarios that depict real-life forensic investigations and the challenges that they present. And, finally, by studying how the existing models from the research community would have behaved in these cases. After performing these three different evaluations, it can be concluded that the results achieved by the proposed methodology were satisfactory, confirmed the feasibility of the proposal and showed clear benefits compared with the related work in terms of practicality and level of detail.
Teaching listening in middle schools: perceptions of practice
Authors: Ramírez-Orellana Daniela , Cárdenas-Claros Mónica S , Cáceres-Ramírez Belen
Published: June 2023

This qualitative case study first examined middle school teacher perceptions of practice regarding L2 listening instruction and, from these, proposes guidelines to favour L2 listening development. Novice middle-school teachers from Chile (n = 14) were guided within semi-structured interviews to reflect on their own L2 listening teaching practices in public and semi-private school classrooms. Verbal reports were transcribed and analysed using thematic analysis techniques and underwent systematic interrogation of qualitative data. The results show an overemphasis on teacher preference for task completion to the detriment of developing listening strategies. We present results and provide guidelines for teachers to integrate features of a metacognitive instruction approach to listening.