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National Soil Organic Carbon Stocks Inventories under Different Mangrove Forest Types in Gabon

Open Journal of Forestry 2024年第2期14卷 127-140页

作者： Rolf Gaël Mabicka Obame Neil-Yohan Musadji Jean Hervé Mve Beh Lydie-Stella Koutika Jean Aubin Ondo Farrel Nzigou Boucka Michel Mbina Mounguengui Claude Geffroy Dé partement de Phytotechnologie Institut National d&#8217Agronomie et de Biotechnologies Universit&#233 des Sciences et Techniques de Masuku Franceville Gabon Dé partement des Sciences Fondamentales de l&#8217Ing&#233nieur Institut National d&#8217Agronomie et de Biotechnologies Universit&#233 des Sciences et Techniques de Masuku Franceville Gabon institut Agronomiques et Forestiè res Centre National des Recherches Scientifiques et Technologiques Libreville Gabon Research Centre on the Durability and the Productivity of Industrial Plantations (CRDPI) Pointe Noire Republic of Congo Laboratoire Pluridisciplinaire des Sciences &#201cole Normale Sup&#233rieure Libreville Gabon Agence Gabonaise d’ &#201tude et d&#8217Observation Spatiale Immeuble les Arcades Libreville Gabon Dé partement de G&#233ologie Faculte des Sciences Universit&#233 des Sciences et Techniques de Masuku Franceville Gabon institut de Chimie des Milieux et Maté riaux de Poitiers (IC2MP) Universit&#233 de Poitiers Poitiers France

Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha−1. Among the different regions, SOC in northern zone was significantly (p p deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha−1) than upper layers (55.42 ± 25.37 MgC ha−1). The study highlights that low deforestation rate have led to less CO2 (705.3 Mg CO2e ha−1 - 922.62 Mg CO2e ha−1) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha−1) than primary (20.33 ± 12.7 MgC ha−1), savanna and cropland (21.71 ± 15.10 MgC ha−1). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.

关键词： Mangroves Forest Soil Organic Carbon Stocks Rizophora Racemose Avicenia germinans Gabon

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Multivariate Approach to Characterizing Soil Quality of Gabonese’s Ferralitic Soils

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Open Journal of Soil Science 2024年第4期14卷 237-268页

作者： Neil-Yohan Musadji Rolf Gaël Mabicka Obame Michel Mbina Mounguengui Jean Aubin Ondo Lydie-Stella Koutika Eric Ravire Claude Geffroy Laboratoire de Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement Des Sciences Fondamentales De L&#8217Ing&#233nieur Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon institut de Chimie des Milieux et Maté riaux De Poitiers (IC2MP) Universit&#233 De Poitiers Poitiers France Laboratoire de Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement De Phytotechnologie Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Dé partement De G&#233ologie Facult&#233 Des Sciences Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Laboratoire Pluridisciplinaire des Sciences Ecole Normale Sup&#233rieure Libreville Gabon Centre de Recherche Sur La Productivité et La Durabilit&#233 Des Plantations Industrielles Pointe Noire Republic of Congo Sucaf Gabon Somdiaa Franceville Gabon

Assessing soil quality is essential for crop management and soil temporal changes. The present study aims to evaluate soil quality in the Ferralitic soils context countrywide. This assessment was done using multivariate soil quality indice (SQI) models, such as additive quality index (AQI), weighted quality indexes (WQIadd and WQIcom) and Nemoro quality index (NQI), applied to two approaches of indicator selection: total data set (TDS) and minimum data set (MDS). Physical and chemical soil indicators were extracted from the ORSTOM’s reports resulting from a sampling campaign in different provinces of Gabon. The TDS approach shows soil quality status according to eleven soil indicators extracted from the analysis of 1,059 samples from arable soil layer (0 - 30 cm depth). The results indicated that 87% of all provinces presented a very low soil quality (Q5) whatever the model. Among soil indicators, exchangeable K+ and Mg2+, bulk density and C/N ratio were retained in MDS, using principal component analysis (PCA). In the MDS approach, 50 to 63% of provinces had low soil quality grades with AQI, WQIadd and NQI, whereas the total was observed with WQIcom. Only 25% of provinces had medium soil quality grades with AQI and NQI models, while 12.5% (NQI) and 25% (AQI) presented high quality grades. Robust statistical analyses confirmed the accuracy and validation (0.80 r P ≤ 0.016) of AQI, WQIadd and NQI into the TDS and MDS approaches. The same sensitivity index value (1.53) was obtained with AQI and WQIadd. However, WQIadd was chosen as the best SQI model, according to its high linear regression value (R2 = 0.82) between TDS and MDS. This study has important implications in decision-making on monitoring, evaluation and sustainable management of Gabonese soils in a pedoclimatic context unfavorable to plant growth.

关键词： Gabon Ferralitic Soil Soil Indicators Standard Score Function Soil Quality Indices Sustainable Soil Soil Management

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Structural characteristics of electrohydrodynamic jets induced by a blade-plane actuator subjected to highly non-uniform electric fields:Parametric investigation through the particle image velocimetry techniques

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High Voltage 2023年第1期8卷 183-195页

作者： Zelu Yan Christophe Louste Philippe Traoré Jian Wu Jian'an Fang Logistics Engineering College Shanghai Maritime UniversityShanghaiChina institut pprime Universitéde PoitiersPoitiersFrance Key Laboratory of Aerospace Thermophysics School of Energy Science and EngineeringHarbin Institute of TechnologyHarbinChina College of Information Science and Technology Donghua UniversityShanghaiChina

This study set out to systematically investigate the structural characteristics of plane electrohydrodynamic jets through the particle image velocimetry(PIV)*** to the wide range of applied voltages and electrode gaps under various experimental conditions,an assessment of the image quality and a statistical analysis of the velocity fields are first performed to ensure the validity of the PIV measurements,which were originally applied purely to fluid *** results indicate that the time interval between two consecutive images should be pre-adjusted to reduce the number of uncorrelated vector ***,the minimum number of instantaneous fields should be achieved for an accurate calculation of the time-averaged *** equivalent electric field criterion adapted to the asymmetric electrode configuration is defined to find similarities in flow structures under different voltage and electrode gap *** the applied electric field increases,three injection regimes are identified and the current increases almost linearly,indicating a large conduction current *** decrease in charge density due to recombination proves to be relevant in all cases of this *** to the parametric analysis approach for classical jets and thermal plumes,the evolution of the coefficients of axial velocity,half-width and turbulence intensity are investigated.

关键词： plane particle blade

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Sediment bed destabilization by an isolated vortex:an experimental approach

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Journal of Hydrodynamics 2021年第2期33卷 370-385页

作者： Yann devaux Lionel Thomas Damien Calluaud Gérard Pineau institut pprime CNRS-Universitéde Poitiers-ISAE-ENSMA-UPR 3346PoitiersFrance

The destabilization of an erodible sediment bed by a reproducible impulsive phenomenon is studied *** this,a specific setup is designed to produce a well-controlled isolated vortex,advected over a uniform sand *** image velocimetry(PIV)measurements are performed to get fluid flow information;suspended particles images are also recorded.A new measurement technique,based on a stereo-correlation method,provides a precise reconstruction of the bedform morphology over *** turbulent structures(namely sweep events)are evidenced in a near-wall region,where particles are mainly *** sediment plume follows the vortex:in particular,the upward velocity inside maintains the suspension ***,the dispersion process seems to be not dependent on the vortex ***,the bed morphology is investigated:a scour hole is dug as the vortex hits the granular *** dynamics is described by a typical scour law,even if the initial perturbation is *** area,where the particles settled,can be observed:it behaves like a ripple,with a logarithmic growth of its *** deposition region has a specific geometry,studied here by a Fourier contour ***,a pickup rate is also derived from the morphological data:it appears independent of the vortex and bedform features.

关键词： Sediment plume isolated vortex stereo-correlation particle image velocimetry(PIV) bedform dynamics

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Numerical micro-texture optimization for lubricated contacts-A critical discussion

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Friction 2022年第11期10卷 1772-1809页

作者： Max MARIAN Andreas ALMQVIST Andreas ROSENKRANZ Michel FILLON department of Mechanical and Metallurgical Engineering Pontificia Universidad Católica de ChileSantiago 690411Chile Division of Machine Elements LuleåUniversity of TechnologyLuleåSE-97187Sweden department of Chemical Engineering Biotechnology and MaterialsFCFMUniversity of ChileSantiago 8370456Chile institut pprime CNRSUniversity of PoitiersPoitiers Cedex TSA 4112386073France

despite numerous experimental and theoretical studies reported in the literature,surface micro-texturing to control friction and wear in lubricated tribo-contacts is still in the trial-and-error *** tribological behaviour and advantageous micro-texture geometries and arrangements largely depend on the contact type and the operating *** scale implementation is hampered by the complexity of numerical *** substantiates the urgent need to numerically design and optimize micro-textures for specific *** these aspects have not been covered by other review articles yet,we aim at summarizing the existing state-of–the art regarding optimization strategies for micro-textures applied in hydrodynamically and elastohydrodynamically lubricated *** analysis demonstrates the great potential of optimization strategies to further tailor micro-textures with the overall aim to reduce friction and wear,thus contributing toward an improved energy efficiency and sustainability.

关键词： micro-texturing hydrodynamics elastohydrodynamics tribo-simulation optimization

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Effects of finite water depth and lateral confinement on ships wakes and resistance

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Journal of Hydrodynamics 2020年第3期32卷 582-590页

作者： Clément Caplier Germain Rousseaux Damien Calluaud Laurent David institut pprime-CNRS University of PoitiersISAE-ENSMAChasseneuilFrance

Wash waves produced by ships disintegrate river banks and coastal lines. This phenomenon of bank erosion is mainly due to the height of the waves. Various factors govern the formation of these waves and their amplitudes: the geometry of the water channel, the shape and the speed of the boat, etc.. These factors play an important role on the wave generation, in addition on the resistance of the ship and so on its fuel consumption. Whether to study the impact of wash waves on the ship's environment or its resistance, the analysis of the generated wake is essential. Hence a fine characterization of the wave field is necessary. This study proposes a comparison of wakes generated by two generic ships based on a Wigley hull with block coefficients 0.67 and 0.89 respectively representative of maritime and fluvial ships. The wakes generated in deep water and confined water configurations have been measured for different Froude numbers by a non-intrusive optical stereo-correlation method, giving access to a detailed and complete definition of the generated wave fields. The resistance of the ship hulls has been measured in deep and confined water configurations with a hydrodynamic balance. The results permit one to study the influence of both hull and water channel geometries on the ship wake, on the amplitude of the far-field generated waves and on the near-field hydrodynamic response. Moreover, resistance curves are obtained for both configurations and highlight the effect of both hull and water channel geometries on the resistance coefficient of the ship. A comparison of the resistance curves with or without the ship trim is conducted and shows the influence of the trim on the resistance coefficient in the different ship speed regimes.

关键词： Ship wakes wash waves confined water ship resistance

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Truncated separation method for characterizing and reconstructing bi-Gaussian stratified surfaces

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Friction 2017年第1期5卷 32-44页

作者： Songtao HU Weifeng HUANG Noel BRUNETIERE Xiangfeng LIU Yuming WANG State Key Laboratory of Tribology Tsinghua University Beijing 100084 China institut pprime CNRS-Universite de Poitiers-ENSMA Futuroscope Chasseneuil Cedex 86962 France

Existing ISO segmented and continuous separation methods for differentiating the two components contained within a bi-Gaussian stratified surface were developed based on the fit of the probability material ratio curve. In the present study, because of the significant effect of the plateau component on tribological behavior such as asperity contact, wear and friction, a truncated separation method is proposed based on the truncation of the upper Gaussian component defined by zero skewness. The three separation methods are applied to real worn surfaces. Surface-separation and surface-reconstruction results show that the truncated method accurately captures the upper component identically to the ISO and continuous ones. The identification of the lower component characteristics requires performing a curve fit procedure on the data left after truncation. However, the truncated method fails in identifying the upper component when the material ratio of the transition is less than 9%.

关键词： surface simulation worn surface stratified surface mechanical face seal

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Experimental Validation of Light Cable-Driven Elbow-Assisting device L-CAdeL design

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Journal of Bionic Engineering 2022年第2期19卷 416-428页

作者： Med Amine Laribi Marco Ceccarelli Juan Sandoval Matteo Bottin Giulio Rosati department GMSC Pprime InstituteCNRS-University of Poitiers-ENSMAUPR 334686073 PoitiersFrance department of Industrial Engineering University of Rome Tor Vergata00133 RomeItaly department of Industrial Engineering University of Padova35122 PaduaItaly

This paper presents a new design of CAdeL,a cable-driven elbow-assisting device,with light weighting and control *** new device design is appropriate to be more portable and user-oriented solution,presenting additional facilities with respect to the original *** of potential benefits of improved portability can be envisaged in the possibility of house and hospital usage keeping social distancing while allowing rehabilitation treatments even during a pandemic *** attention has been devoted to design main mechatronic components by developing specific kinematics *** design process includes an implementation of specific control hardware and *** kinematic model of the new design is formulated and features are evaluated through numerical simulations and experimental *** evaluation from original design highlights the proposed improvements mainly in terms of comfort,portability and user-oriented operation.

关键词： Rehabilitation robotics Medical devices design Simulations Cable-driven parallel robot Control

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Complementary Methods to Acquire the Kinematics of Swimming Snakes:A Basis to design Bio-inspired Robots

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Journal of Bionic Engineering 2023年第2期20卷 668-682页

作者： Elie Gautreau Xavier Bonnet Tom Fox Guillaume Fosseries Valéry Valle Anthony Herrel Med Amine Laribi department of GMSC University of PoitiersISAE-ENSMACNRSPPRIME UPR 3346PoitiersFrance CEBC Center for Biological Studies of Chizé CNRS and University of la RochelleVilliers en BoisFrance MNHN National Museum of Natural History CNRSParisFrance

The vast diversity of morphologies,body size,and lifestyles of snakes represents an important source of information that can be used to derive bio-inspired robots through a biology-push and pull *** understanding of the detailed kinematics of swimming snakes is a fundamental prerequisite to conceive and design bio-inspired aquatic snake ***,only limited information is available on the kinematics of swimming *** and accurate methods are needed to fill this knowledge *** the present paper,three existing methods were compared to test their capacity to characterize the kinematics of swimming snakes.(1)Marker tracking(deftac),(2)Markerless pose estimation(deepLabCut),and(3)Motion capture were considered.(4)We also designed and tested an automatic video processing *** methods provided different albeit complementary data sets;they also involved different technical issues in terms of experimental conditions,snake manipulation,or processing *** tracking provided accurate data that can be used to calibrate other *** capture posed technical difficulties but can provide limited 3D *** pose estimation required deep learning(thus time)but was efficient to extract the data under various experimental ***,automatic video processing was particularly efficient to extract a wide range of data useful for both biology and robotics but required a specific experimental setting.

关键词： Locomotion Image processing Motion capture Kinematic analysis Snake robot Biomimicry deepLabCut

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Cable-Driven Parallel Robot Workspace Identification and Optimal design Based on the Upper Limb Functional Rehabilitation

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Journal of Bionic Engineering 2022年第2期19卷 390-402页

作者： Ferdaws Ennaiem Abdelbadia Chaker Juan Sandoval Sami Bennour Abdelfattah Mlika Lotfi Romdhane Said Zeghloul Med Amine Laribi department of GMSC Pprime Institute CNRSENSMAUniversity of PoitiersUPR 3346PoitiersFrance Mechanical Laboratory of Sousse(LMS) National Engineering School of SousseUniversity of Sousse4000 SousseTunisia American University of Sharjah PO Box 26666SharjahUnited Arab Emirates

An assessment of the human motion repeatability for three selected Activities of Daily Living(ADL)is performed in this *** exercises were prescribed by an occupational therapist for the upper limb *** movement patterns of five participants,recorded using a Qualisys motion capture system,are compared based on the Analysis of Variance(ANOVA)*** survey is motivated by the need to find the appropriate task workspace of a 6-degrees of freedom cable-driven parallel robot for upper limb rehabilitation,which is able to reproduce the three selected *** comparison is performed to justify,whether or not,there is enough similarity between the participants’gestures,and so a single reference trajectory can be adopted as the robot-prescribed *** the results of the comparative study,an optimization process of the sought robot design is carried out,where the structure size and the cable tensions simultaneously minimized.

关键词： Human motion repeatability Activities of Daily Living(ADL) Analysis of Variance(ANOVA) Task workspace Cable-driven parallel robot Upper limb rehabilitation Optimization

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