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Origami multi-layer space shield for cylindrical space structure

Chinese Journal of Aeronautics 2024年第10期37卷 294-312页

作者： Ji-Hun CHA Ji-Sub NOH Sarath Kumar SATHISH KUMAR Dohyeon JIN Dae-Young LEE Chun-Gon KIM department of aerospace Engineering Chosun UniversityGwangju 61452Republic of Korea department of aerospace and Software Engineering Gyeongsang National UniversityGyeongsangnam-do 52828Republic of Korea department of aerospace Engineering Seoul National UniversitySeoul 08826Republic of Korea department of aerospace Engineering KAISTDaejeon 34141Republic of Korea

The multidisciplinary space environment,encompassing orbital debris,cosmic radiation,and solar radiative heat,poses significant risks to spacecraft and astronauts,necessitating efficient and effective shielding solutions.A multi-layer shield with wide spacing has been proven to be an effective way to shield the spacecraft from space debris impact;however,due to the limited volume of the payload fairing,it was not feasible to apply a multi-layer shield to the spacecraft *** the origami design,the shield maintains a compact form during launch and subsequently expands in outer space to enhance *** geometric analysis,it has been confirmed that the deployable multi-layer space shield can occupy less space than conventional space shield structures while expanding into wider shield intervals and multiple *** hypervelocity impact experiments,it was confirmed that as the bumper spacing of the multi-layer space shield expands,its ballistic performance becomes superior to conventional space *** deployable multi-layer space shield can reduce not only hypervelocity impacts but also solar radiative heat using the same mechanism as multi-layer *** cosmic radiation dose analysis,it has been confirmed that the multi-layer space shield is effective in cosmic radiation shielding compared to conventional space structures.

关键词： Hybrid composite Origami Hypervelocity impact Space environment Space debris Cosmic radiation

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Multidisciplinary design optimization of a dual-spin guided vehicle

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Defence Technology（防务技术） 2024年第7期37卷 133-148页

作者： Jalal Karimi Mohammad Reza Rajabi Seyed Hossein Sadati Seyed Mahid Hosseini department of aerospace Engineering Malek Ashtar University of TechnologyTehranIran

In this research,a Multidisciplinary Design Optimization approach is proposed for the dual-spin guided flying projectile design considering external and internal parts of the body as design *** this way,a parametric formulation is *** related disciplines,including structure,aerodynamics,guidance,and control are *** total mass,maximum aerodynamic control effectiveness,minimum miss distance,maximum yield stress in all subsystems,controllability and gyroscopic stability constraints are some of objectives/constraints taken into *** problem is formulated in All-At-Ones Multidisciplinary Design Optimization approach structure and solved by Simulated Annealing and minimax *** optimal configurations are evaluated in various *** resulted optimal configurations have met all design objectives and constraints.

关键词： Flying projectile optimal design All-at-ones multidisciplinary optimization Structure discipline Guidance and control discipline Aerodynamic discipline

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A path planning algorithm for a crop monitoring fixed-wing unmanned aerial system

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Science China(Information Sciences) 2024年第08期67卷 5-23页

作者： Longhao QIAN Yi Lok LO Hugh Hong-tao LIU Institute of aerospace Studies University of Toronto department of Mechanical Engineering The University of Hong Kong

With the growing demand for automation in agriculture, industries increasingly rely on drones to perform crop monitoring and surveillance. In this regard, fixed-wing unmanned aerial systems(UASs)are viable platforms for scanning a large crop field, given their payload capacity and range. To achieve maximum coverage without landing for battery replacement, an algorithm for producing a minimal required energy survey path is essential. Hence, an energy-aware coverage path planning algorithm is proposed *** constraints for a fixed-wing UAS to fly at low altitudes while achieving full coverage of the crop field are first analyzed. Then, the full path is decomposed into straight-line and U-turn primitives. Finally, an algorithm to calculate a combination of straight-line segments and U-turns is proposed to obtain the path with minimum required energy consumption. The genetic algorithm is used to efficiently determine the order of the straight-line paths to traverse. Case studies show that the proposed algorithm can produce planning results for a convex-polygon-shaped crop field.

关键词： path planning genetic algorithm energy minimization fixed-wing UAS aerial survey

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Fine-Grained Ship Recognition Based on Visible and Near-Infrared Multimodal Remote Sensing Images: Dataset,Methodology and Evaluation

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Computers, Materials & Continua 2024年第6期79卷 5243-5271页

作者： Shiwen Song Rui Zhang Min Hu Feiyao Huang department of aerospace Science and Technology Space Engineering UniversityBeijing101416China

Fine-grained recognition of ships based on remote sensing images is crucial to safeguarding maritime rights and interests and maintaining national ***,with the emergence of massive high-resolution multi-modality images,the use of multi-modality images for fine-grained recognition has become a promising ***-grained recognition of multi-modality images imposes higher requirements on the dataset *** key to the problem is how to extract and fuse the complementary features of multi-modality images to obtain more discriminative fusion *** attention mechanism helps the model to pinpoint the key information in the image,resulting in a significant improvement in the model’s *** this paper,a dataset for fine-grained recognition of ships based on visible and near-infrared multi-modality remote sensing images has been proposed first,named Dataset for Multimodal Fine-grained Recognition of Ships(DMFGRS).It includes 1,635 pairs of visible and near-infrared remote sensing images divided into 20 categories,collated from digital orthophotos model provided by commercial remote sensing *** provides two types of annotation format files,as well as segmentation mask images corresponding to the ship ***,a Multimodal Information Cross-Enhancement Network(MICE-Net)fusing features of visible and near-infrared remote sensing images,has been *** the network,a dual-branch feature extraction and fusion module has been designed to obtain more expressive *** Feature Cross Enhancement Module(FCEM)achieves the fusion enhancement of the two modal features by making the channel attention and spatial attention work cross-functionally on the feature map.A benchmark is established by evaluating state-of-the-art object recognition algorithms on ***-Net conducted experiments on DMFGRS,and the precision,recall,mAP0.5 and mAP0.5:0.95 reached 87%,77.1%,83.8%and 63.9%,*** experiments demons

关键词： Multi-modality dataset ship recognition fine-grained recognition attention mechanism

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Synthesis and characterization of ultra-soft alginate hydrogel mimicking lung tissue

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International Journal of Smart and Nano Materials 2024年第3期15卷 593-609页

作者： Xiangpeng Li Jihua Gou Chiranjit Maiti Olusegun J.Ilegbusi department of Mechanical and aerospace Engineering University of Central FloridaOrlandoFLUSA

Alginate hydrogels possess properties analogous to those of the extracellular matrix(ECM).Thus,their mechanical behavior approx-imates soft tissue,which makes them desirable for the production of tissue-equivalent soft deformable *** study aims to determine the synthesis-structure-property relationship for alginate hydrogel with the Young’s modulus in the range of 10°~101 kPa,mimicking to that of human lung ***,a 3D polymer network embedded in a water-rich *** alginate hydrogels are synthesized by a direct mixture of sodium alginate and CaCO3,followed by the addition of D-glucono-δ-lactone(GDL)to initiate in-situ Ca^(2+)release and *** influence of alginate concentration and molar ratio of the constitu-ent calcium ion to carboxyl group from alginate monomer are evaluated while the Young’s modulus of the hydrogel is carefully controlled within the desired *** and SEM are used to characterize the influence of synthesis parameters at the molecular and microstructure *** and compression testing are performed to determine the Young’s modulus of the *** relations are established between synthesis parameters and the mechanical *** result of the study will be subse-quently used to guide the additive manufacturing of soft deform-able structures based on alginate hydrogels.

关键词： Alginate hydrogels Ultra-low modulus lung tissue-mimicking materials

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Characterization of Gauss–Markov stochastic sequences for mission analysis

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Astrodynamics 2024年第1期8卷 135-148页

作者： Carmine Giordano department of aerospace Science and Technology Politecnico di MilanoMilano20156Italy

In real scenarios,the spacecraft deviates from the intended paths owing to uncertainties in dynamics,navigation,and command *** quantifying these uncertainties is crucial for assessing the observability,collision risks,and mission *** issue is further magnified for CubeSats because they have limited control authority and thus require accurate dispersion estimates to avoid rejecting viable trajectories or selecting unviable *** uncertainties arise from random variables(e.g.,measurement errors and drag coefficients)and processes(e.g.,solar radiation pressure and low-thrust acceleration).Although random variables generally present minimal computational complexity,handling stochastic processes can be challenging because of their noisy ***,accurately modeling these processes is essential,as they significantly influence the uncertain propagation of space trajectories,and an inadequate representation can result in either underestimation or overestimation of the stochastic characteristics associated with a given *** study addresses the gap in characterizing process uncertainties,represented as Gauss–Markov processes in mission analysis,by presenting models,evaluating derived quantities,and providing results on the impact of spacecraft *** study emphasizes the importance of accurately modeling random processes to properly characterize stochastic spacecraft paths.

关键词： Gauss-Markov process uncertainty quantification stochastic dynamics Monte Carlo simulation

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Recent Development of Heat Transfer and Fluid Flow of Supercritical CO2 in Tubes:Mechanisms and Applications

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Journal of Thermal Science 2024年第06期33卷 2274-2298页

作者： ZHANG Xirui SHAO Qihan LIU Jian XI Wenxiong LIU Chaoyang SUNDEN Bengt Research Institute of aerospace Technology Central South University College of aerospace Science and Engineering National University of Defense Technology department of Energy Sciences Lund University

With the advantages of low cost,excellent ability of heat and mass transfer and easy accessibility to the supercritical point,supercritical CO2has been applied in many engineering devices *** of the sharply-varying thermophysical properties near the supercritical point,heat transfer and flow behavior of supercritical CO2in tubes become complex and have received a lot of research *** main purpose of this paper is to summarize the findings of the published works related to flow phenomena and heat transfer characteristics of supercritical ***,influence parameters related to boundary conditions of supercritical CO2flowing in a smooth tube are ***,commonly-used turbulence and mathematic models dealing with internal flows of supercritical CO2are ***,research works on geometric effects of design parameters,shapes and configurations are *** practical applications of supercritical CO2in recent years are ***,developments and future challenges of supercritical CO2in tubes are analyzed and *** paper provides basic knowledge of heat transfer and fluid flow mechanisms and related practical applications of supercritical CO2in tubes.

关键词： developments and challenges flow behavior heat transfer practical applications supercritical CO2

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Hematuria after nocturnal exercise of a man: A case report

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World Journal of Clinical Cases 2024年第5期12卷 1025-1028页

作者： Ming-Jian Bai Song-Tao Yang Xue-Kai Liu department of Clinical Laboratory Aerospace Center HospitalBeijing 100049China department of Nephrology Aerospace Center HospitalBeijing 100049China

BACKGROUND A man experienced multiple episodes of macroscopic hematuria following nocturnal *** stones and tumors were considered the two most likely *** patient had two hobbies:Consuming health care products in large quantities and engaging in late-night *** SUMMARY Health care products contain a large amount of calcium phosphate,and we hypothesize that this could induce the formation of small phosphate *** exercise,the urinary system is abraded,resulting in *** patient was advised to stop using the health care ***,the aforementioned symptoms disappeared ***,the patient resumed the above two habits one year later;correspondingly,the macroscopic hematuria *** This finding further confirmed the above inference and allowed for a new avenue to determine the cause of the patient’s hematuria.

关键词： Hematuria Health care products Exercise Case report

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Experimental evaluation of mechanical compression of lattice trusses made with Ti6Al4V for aerospace use

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Chinese Journal of Aeronautics 2024年第5期37卷 520-532页

作者： Carlo Giovanni FERRO Sara VARETTI Paolo MAGGIORE department of Mechanical and aerospace Engineering Politecnico di TorinoCorso Duca degli AbruzziTorino 10124Italy

Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of materials.A smart use of materials leads to reduced fuel consumption and lower operating costs,making them highly desirable for aircraft ***,the customizable properties of lattice structures allow for tailoring to specific design requirements,leading to improved performance and safety for *** advantages make lattice structures an important focus for research and development in the aviation *** paper presents an experimental evaluation of the mechanical compression properties of lattice trusses made with Ti6Al4V,designed for use in an anti-ice *** truss structures were manufactured using additive manufacturing techniques and tested under compressive loads to determine mechanical *** showed that lattice trusses exhibited high levels of compressive strength,making them suitable for use in applications where mechanical resistance and durability are critical,such as in anti-ice *** also highlight the potential of additive manufacturing techniques for the fabrication of lattice trusses with tailored mechanical *** study provides valuable insights into the mechanical behavior of Ti6Al4V lattice trusses and their potential applications in anti-ice systems,as well as other areas where high strength-to-weight ratios are *** results of this research contribute to the development of lightweight,efficient,and durable anti-ice systems for use in aviation and other industries.

关键词： Additive Manufacturing(AM) Selective Laser Sintering(SLM) Anti ice systems Lattice structures Aircraft on board systems Design of Experiments(DOE)

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Modeling urban scale human mobility through big data analysis and machinelearning

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Building Simulation 2024年第1期17卷 3-21页

作者： Yapan Liu Bing Dong department of Mechanical&aerospace Engineering Syracuse University263 Link HallSyracuseNY 13244USA

In the United States,the buildings sector consumes about 76%of electricity use and 40% of all primary energy use and associated greenhouse gas *** behavior has drawn increasing research interests due to its impacts on the building energy ***,occupant behavior study at urban scale remains a challenge,and very limited studies have been *** an effort to couple big data analysis with human mobility modeling,this study has explored urban scale human mobility utilizing three months Global Positioning System(GPS)data of 93,o00 users at Phoenix Metropolitan *** research extracted stay points from raw data,and identified users'home,work,and other locations by Density-Based Spatial Clustering ***,daily mobility patterns were constructed using different types of *** propose a novel approach to predict urban scale daily human mobility patterns with 12-hour prediction horizon,using Long Short-Term Memory(LSTM)neural network *** shows the developed models achieved around 85%average accuracy and about 86%mean *** developed models can be further applied to analyze urban scale occupant behavior,building energy demand and flexibility,and contributed to urban planning.

关键词： urban human mobility big data analysis urban scale occupant behavior recurrent neural networks

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