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Integration of a hybrid vibration prediction model for railways into noise mapping software: methodology, assumptions and demonstration

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RAILWAY ENgINEERINg SCIENCE 2025年第1期33卷 1-26页

作者： Reumers, Pieter Degrande, geert Lombaert, geert Thompson, David J. Ntotsios, Evangelos Bouvet, Pascal Nelain, brice Nuber, Andreas Katholieke Univ Leuven Dept Civil Engn Kasteelpk Arenberg 40 B-3001 Leuven Belgium Univ Southampton ISVR Southampton SO17 1BJ England Vibratec 28 Chemin Petit Bois F-69131 Ecully France Woelfel Engn gmbH Co K Max Planck Str 15 D-97204 Hoechberg Germany

Within the SILVARSTAR project, a user-friendly frequency-based hybrid prediction tool has been developed to assess the environmental impact of railway-induced vibration. This tool is integrated in existing noise mapping software. Following modern vibration standards and guidelines, the vibration velocity level in a building in each frequency band is expressed as the sum of a force density (source term), line source transfer mobility (propagation term) and building correction factor (receiver term). A hybrid approach is used that allows for a combination of experimental data and numerical predictions, providing increased flexibility and applicability. The train and track properties can be selected from a database or entered as numerical values. The user can select soil impedance and transfer functions from a database, pre-computed for a wide range of parameters with state-of-the-art models. An experimental database of force densities, transfer functions, free field vibration and input parameters is also provided. The building response is estimated by means of building correction factors. Assumptions within the modelling approach are made to reduce computation time but these can influence prediction accuracy;this is quantified for the case of a nominal intercity train running at different speeds on a ballasted track supported by homogeneous soil of varying stiffness. The paper focuses on the influence of these parameters on the compliance of the track-soil system and the free field response. We also demonstrate the use and discuss the validation of the vibration prediction tool for the case of a high-speed train running on a ballasted track in Lincent (Belgium).

关键词： Railway-induced vibration Hybrid vibration prediction model Experimental validation Low-speed approximation

A Review of Research Activities for the Perspective of a Smart Electricity grid in Burkina Faso

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Smart grid and Renewable Energy 2025年第1期16卷 1-12页

作者： brice Junior Carmel Wendenda Ilboudo Ollé Michel Kam Raguilignaba Sam Laboratoire de Matriaux dHeliophysique et Environnement (LaMHE) Dpartement de Physique Universit Nazi BONI Bobo-Dioulasso Burkina Faso Laboratoire de Matriaux et Environnement (LAME) Dpartement de Physique Universit Joseph KI ZERBO Ouagadougou Burkina Faso Science du Numrique Universit Virtuelle du Burkina Faso (UV-BF) Ouagadougou Burkina Faso

This review explores the research activities surrounding the development and integration of smart electricity grids in Burkina Faso, a landlocked and arid territory in West Africa and one of the poorest countries in the world with significant energy challenges. It examines the current state of energy infrastructure in Burkina Faso, focusing on the integration of renewable energy sources, particularly solar photovoltaics. It highlights the role of smart grid technologies in enabling the efficient integration of renewable energy, improving grid stability and facilitating rural electrification. Additionally, the review addresses key challenges such as inadequate infrastructure, regulatory gaps and financial constraints that hinder the deployment of smart grids in the country. By analysing existing research and ongoing projects, this paper provides a comprehensive overview of the opportunities and barriers to implementing a smart electricity grid in Burkina Faso and offers recommendations for future development and policy frameworks.

关键词： Smart grid Smart Building Decentralised Energy Production Photovoltaic Renewable Energy

Mothers’ Knowledge and Practices Regarding Exclusive Breastfeeding in the Central African Republic

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Open Journal of Pediatrics 2025年第1期15卷 74-92页

作者： Hilda Josephe Touadera Mongboa brice Olivier Bogning Mejiozem Jean Chrysostome gody Fondation Tina Touadera Bangui Central African Republic Centre Hospitalier Universitaire Pdiatrique de Bangui Bangui Central African Republic Facult des Sciences de la Sant Universit de Bangui Bangui Central African Republic

Introduction: Breastfeeding is the best way to provide ideal nutrition for optimal infant growth and development. Objectives: The aim of our work was to assess the knowledge, attitudes and practices of mothers of children aged 0 - 24 months on exclusive breastfeeding in the Central African Republic. Methods: This was a cross-sectional, descriptive and analytical study conducted from September 15 to October 15, 2024 among mothers of infants aged 0 to 24 months. Sociodemographic, obstetric and breastfeeding-related data were collected through individual interviews conducted during sensitizations on good feeding practices organized by the Tina Touadera Foundation. The chi2 test was used to test for relationships between variables, and the p significance level was set at 0.05. Results: The average age of the mothers surveyed was 27.67 years. 65.69% (n = 247) of mothers lived in urban areas and 55.85% (n = 210) were Muslim. 56.38% (n = 212) were living common-law and 34.04% (n = 128) were poor. Secondary-school mothers (44.42%, n = 167) and housewives (53.72%, n = 202) were in the majority. Exclusive breastfeeding (EBF) was correctly defined by 79.26% (n = 298) of mothers and actually practised in 24.20% (n = 91) of cases. The main source of information was a health professional in 75.36% (n = 304) of cases. Among the 285 mothers who practised mixed breastfeeding, lack of time (33.33%) was the main reason. They acknowledged having given water (100%), corn porridge (75.09%) and/or artificial milk (24.91%) before the first 6 months of life. The average time for introducing water was 2.2 months, and for porridge/formula 2.79 months. More than half the mothers (55.05%) said they did not know their infants’ weaning age. Factors positively influencing the use of EBF were age under 29, residence in an urban area, primiparity, having been informed about AME by a health professional, and being a housewife or shopkeeper (p Conclusion: Mothers’ level of knowledge was heterogeneous

关键词： EBF Knowledge Attitudes Practices Mothers CAR

Validation of Monthly Data of Temperature and Precipitation over West Africa from Simulations of CORDEX-CORE Ensemble

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Journal of geoscience and Environment Protection 2025年第1期13卷 422-443页

作者： Alphonse Um Um Cyrille Meukaleuni Eric Efon brice Baudouin Sandjeu Wandjie Rinelle Djiondo Ngongang Alain Tchio Tamoffo Carine Betant Andre Lenouo Laboratory of Fundamental Physics Department of Physics Faculty of Science University of Douala Douala Cameroon The University Institute of the Coast Douala Cameroun Department of Physics Faculty of Science University of Bamenda Cameroon Climate Service Center germany (gERICS) Helmholtz-Zentrum Hereon Hamburg Germany

We analysed nine simulations from dynamic downscaling to a horizontal resolution of approximately 25 km of three general circulation models (gCMs). These gCMs use three regional climate models (RCMs) that participated in the coordinated downscaling experiment (CORDEX-CORE). These simulations were compared to three datasets of reanalysis. The ERA5 for temperature at 2 metres and for precipitation, Climate Hazards Center InfraRed Precipitation with Stations (CHIRPS) and African Rainfall Climatology from the Famine Early Warning System (FEWS-ARC) were used. To give an overview of these nine model experiments, we presented and compared the results of the latter with the reanalysis taken into account for the period 1983 - 2005. The results indicated that the nine models correctly reproduced the temperature and rainfall in West Africa during the historical period. In the guinean coast region, REMO-NorESM1 and RegCM4-MPI-MR models well simulated precipitation and temperature during the historical period. In the Savannah region, RegCM4-NorESM1, CCLM5-MPI-LR, REMO-NorESM1, CCLM5-NorESM1 and CCLM5-HadgEM2 model gave best result. In the Sahel region, the RegCM4-HadgEM2 model gave a good correlation. Using the Taylor diagram in the historical period, all CORDEX-CORE RCMs had a strong relationship with temperature.

关键词： CORDEX-CORE Regional Climate Model Evaluation ERA5 CHIRPS FEWS-ARC West Africa

An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of geotechnical Structures

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 251-277页

作者： Sourabh Mhaski g.V.Ramana Department of Civil Engineering Indian Institute of Technology DelhiNew Delhi110016India

Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures *** understanding of the liquefaction triggering,and the post-failure large deformation behaviour is essential for designing resilient *** present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of geotechnical *** coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase,single-layer SPH framework.A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile ***,non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are *** numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level ground site,and liquefaction-induced failure of the Lower San Fernando *** agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical *** present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.

关键词： Earthquake seismic liquefaction stress particle PM4Sand smoothed particle hydrodynamics(SPH)

Projective Hilbert modules and sequential approximations

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Science China Mathematics 2025年第1期68卷 137-168页

作者： Lawrence g.Brown Huaxin Lin Department of Mathematics Purdue UniversityWest LafayetteIN 47907-2067USA Department of Mathematics East China Normal UniversityShanghai 200062China Department of Mathematics University of OregonEugeneOR 97405USA

We show that when A is a separable C^(*)-algebra,every countably generated Hilbert A-module is projective(with bounded module maps as morphisms).We also study the approximate extensions of bounded module *** the case where A is aσ-unital simple C^(*)-algebra with strict comparison,and every strictly positive lower semicontinuous affine function on quasitraces can be realized as the rank of an element in the Cuntz semigroup,we show that the Cuntz semigroup is equivalent to unitarily equivalent classes of countably generated Hilbert A-modules if and only if A has stable rank one.

关键词： projective Hilbert modules simple C^(*)-algebras sequential approximations

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Integration of a hybrid vibration prediction model for railways into noise mapping software: methodology, assumptions and demonstration

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Railway Engineering Science 2025年第01期 1-26页

作者： Pieter Reumers geert Degrande geert Lombaert David J.Thompson Evangelos Ntotsios Pascal Bouvet brice Nélain Andreas Nuber Department of Civil Engineering KU Leuven ISVR University of Southampton Vibratec 28 Chemin du petit bois Woelfel Engineering GmbH+Co.K

Within the SILVARSTAR project, a user-friendly frequency-based hybrid prediction tool has been developed to assess the environmental impact of railway-induced vibration. This tool is integrated in existing noise mapping software. Following modern vibration standards and guidelines, the vibration velocity level in a building in each frequency band is expressed as the sum of a force density(source term), line source transfer mobility(propagation term) and building correction factor(receiver term). A hybrid approach is used that allows for a combination of experimental data and numerical predictions, providing increased flexibility and applicability. The train and track properties can be selected from a database or entered as numerical values. The user can select soil impedance and transfer functions from a database, pre-computed for a wide range of parameters with state-of-the-art models. An experimental database of force densities, transfer functions, free field vibration and input parameters is also provided. The building response is estimated by means of building correction factors. Assumptions within the modelling approach are made to reduce computation time but these can influence prediction accuracy; this is quantified for the case of a nominal intercity train running at different speeds on a ballasted track supported by homogeneous soil of varying stiffness. The paper focuses on the influence of these parameters on the compliance of the track–soil system and the free field response. We also demonstrate the use and discuss the validation of the vibration prediction tool for the case of a high-speed train running on a ballasted track in Lincent(Belgium).

关键词：

On Sawada-Kotera and Kaup-Kuperschmidt integrable systems

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Communications in Theoretical Physics 2025年第2期77卷 23-31页

作者： Metin gürses Asl| Pekcan Department of Mathematics Faculty of Science Bilkent University Department of Mathematics Faculty of Science Hacettepe University

To obtain new integrable nonlinear differential equations there are some well-known methods such as Lax equations with different Lax representations. There are also some other methods that are based on integrable scalar nonlinear partial differential equations. We show that some systems of integrable equations published recently are the M2-extension of integrable such scalar equations. For illustration, we give Korteweg–de Vries, Kaup-Kupershmidt, and SawadaKotera equations as examples. By the use of such an extension of integrable scalar equations, we obtain some new integrable systems with recursion operators. We also give the soliton solutions of the systems and integrable standard nonlocal and shifted nonlocal reductions of these systems.

关键词： recursion operator nonlocal reductions Hirota bilinear form soliton solutions .M2-extension recursion operator nonlocal reductions Hirota bilinear form soliton solutions

Stepping up after spinal cord injury:negotiating an obstacle during walking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly g.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury

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