In this research, the novel metaheuristic algorithm Harris hawks optimization (HHO) is applied to landslide susceptibility analysis in Western Iran. To this end, the HHO is synthesized with an ...artificial neural network (ANN) to optimize its performance. A spatial database comprising 208 historical landslides, as well as 14 landslide conditioning factors-elevation, slope aspect, plan curvature, profile curvature, soil type, lithology, distance to the river, distance to the road, distance to the fault, land cover, slope degree, stream power index (SPI), topographic wetness index (TWI), and rainfall-is prepared to develop the ANN and HHO-ANN predictive tools. Mean square error and mean absolute error criteria are defined to measure the performance error of the models, and area under the receiving operating characteristic curve (AUROC) is used to evaluate the accuracy of the generated susceptibility maps. The findings showed that the HHO algorithm effectively improved the performance of ANN in both recognizing (AUROC
= 0.731 and AUROC
= 0.777) and predicting (AUROC
= 0.720 and AUROC
= 0.773) the landslide pattern.
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•A novel approach introduced to model and assess an urban morphology.•1600 urban models are generated and evaluated considering urban microclimate.•An optimal technique is introduced ...for ventilation regarding the air pollution.•10.2% cooling demand reduction and 15.2% ventilation potential increase is observed.•Design-based suggestions are presented as a guide for newly-built urban areas.
Cooling buildings in urban areas with hot-arid climate put huge loads on the energy system. There is an increasing trend in urban energy studies to recognize the urban design variables and parameters associated with the energy performance of buildings. In this work, a novel approach is introduced to investigate the impacts of urban morphology on cooling load reduction and enhancing ventilation potential by studying a high-rise building (target building), surrounded by different urban configurations, during six warm months of the year in Tehran at four major sections including: (1) generating 1600 urban case studies considering three parameters (Urban Density, Urban Building Form, and Urban Pattern) and modelling the urban morphology of Tehran based on a technique namely “Building Modular Cells”, (2) validation study of CFD simulation of the wind flow around buildings, (3) calculating the average cooling load and wind flow at the rooftop of the target building, and (4) investigating sixteen best urban configurations with the lowest cooling load and highest ventilation potential. Results indicate that urban morphology has a notable impact on the energy consumption of buildings, decreasing cooling load and increasing ventilation potential more than 10% and 15% respectively, compared to the typical cases. This work also proposes design solutions for architects and urban designers, based on Top 100 configurations (out of 1600), for improved energy performance and better ventilation of buildings in urban areas.
In this paper, an electro-hydraulic servo resonance technology is proposed to meet the loading requirements of a high-frequency sound fatigue test for large tonnage. First of all, we analyze the ...static and dynamic loading structure of electro-hydraulic servo vibration and establish the vibration equation of the system. Additionally, the modal and vibration characteristics of the system are analyzed by simulation, which verified the feasibility of the proposed electro-hydraulic servo resonant loading technology. Finally, the influence of various factors such as sample stiffness, lead screw stiffness, class II spring stiffness, class II weight mass, lower beam mass, and upper beam mass on the natural frequency and amplification coefficient of the system is analyzed. In this paper, a new technology is proposed to provide theoretical support for the research and development of large-tonnage high-frequency noise fatigue testing equipment.
•We process two months mobile network trajectories from the Greater Paris region.•The transport mode is inferred from all trajectories, using few labeled data.•Total road and rail OD flows are ...estimated over time at different resolutions.•The estimates are validated against survey and travel cards flows.
Fast urbanization generates increasing amounts of travel flows, urging the need for efficient transport planning policies. In parallel, mobile phone data have emerged as the largest mobility data source, but are not yet integrated to transport planning models. Currently, transport authorities are lacking a global picture of daily passenger flows on multimodal transport networks. In this work, we propose the first methodology to infer dynamic Origin-Destination flows by transport modes using mobile network data e.g., Call Detail Records. For this study, we pre-process 360 million trajectories for more than 2 million devices from the Greater Paris as our case study region. The model combines mobile network geolocation with transport network geospatial data, travel survey, census and travel card data. The transport modes of mobile network trajectories are identified through a two-steps semi-supervised learning algorithm. The later involves clustering of mobile network areas and Bayesian inference to generate transport probabilities for trajectories. After attributing the mode with highest probability to each trajectory, we construct Origin-Destination matrices by transport mode. Flows are up-scaled to the total population using state-of-the-art expansion factors. The model generates time variant road and rail passenger flows for the complete region. From our results, we observe different mobility patterns for road and rail modes and between Paris and its suburbs. The resulting transport flows are extensively validated against the travel survey and the travel card data for different spatial scales.
Dynamic response levels are critical for tall and slender civil structures. Studying the dynamic behavior of large civil structures with finite element modeling techniques requires detailed and ...accurate modeling of structural geometry, material properties, member fixities, connection types, and accompanying assumptions. Still, the finite element model results are approximations that could be away from representing the actual structural behavior. Structures are dynamically tested at their operational conditions to validate the finite element model results. This paper presents Operational Modal Analysis (OMA) and finite element model updating of a tall structure located in the West Bay area of Doha (Qatar). The structure is a reinforced concrete building with shear wall cores situated towards the center of the building plan, which was constructed between 2012 and 2016. With 53 stories above the ground and two stories below ground, the 230 m (755 ft) tall building is being used for residential and hotel purposes. For the finite element model updating and calibration tasks presented in this paper, the authors intentionally introduced drastic model changes for the first two model updates so that the results from the first two attempts guide how to proceed with a more reasonable update for the third calibration of the finite element model. While this is a non-standard technique that represents a specific condition where the initial attempts on the finite element model are very crude approximations, it is a systematized demonstration of how to operate when the structural parameters are sparse or uncertain for modeling purposes. While in theory, the finite element model updates can always be fine-tuned in a way to further decrease the error between the measured and predicted OMA results, in this paper, the authors predominantly focused on the presentation of three finite element model updates to demonstrate the way they have improved the modal assurance criteria plots and lowered the average absolute errors by visiting two drastic and then one moderate finite element model updates. The material presented here in this paper is arguably the first published work on large-scale dynamic testing of a civil structure in the State of Qatar.
La spécificité des sols gonflants est peu abordée dans les formations de mécanique des sols et de géotechnique, malgré la gravité des problèmes qu’ils peuvent engendrer sur les structures ...géotechniques. Parmi d’autres travaux, la réalisation actuelle du réseau du Grand Paris Express est concernée par les différents niveaux de sols gonflants des dépôts du Bassin Parisien. Après une présentation de quelques caractéristiques typiques des sols gonflants, qui sont saturés, plastiques et surconsolidés dans le cas de la région parisienne, on décrit les mécanismes de base permettant d’expliquer le gonflement des sols argileux. Quelques remarques relatives au comportement macroscopique des sols gonflants du Bassin Parisien, sur lesquels peu de données sont disponibles dans la bibliographie, sont ensuite proposées.
The specificity of swelling soils is rather seldom considered in Soil Mechanics and Geotechnical Engineering education, in spite of the gravity of the problems on geotechnical structures that may result from their particular behaviour features. This is particularly true in the context of the on-going works of the Grand Paris Express network, due to the presence of various layers of swelling soils in the Parisian Basin. After presenting some typical behaviour features of swelling soils, that are saturated, plastic and over-consolidated in the Parisian Basin, one describes the basic mechanisms of swelling in clayey soils. Some consequences with respect to the swelling soils of the Paris area, on which rather few literature data are available, are drawn.
Liquid corner films in channels or pores of polygonal cross-section are known to have a strong impact on evaporation with a much faster evaporation compared to a tube of circular cross section. The ...aim of this work is to study the interplay between colloidal particles, development of the corner films and evaporation in a micro channel from a combination of visualization experiments with fluorescent particles and numerical simulations. It is shown that the triple line pinning along the corner films due to particle accumulation in the films leads to the thinning of the corner films. As a result of the film thinning, evaporation is slower in the presence of particles compared to pure water. The identification of such an evaporation reduction mechanism at pore scale shed new light on the phenomenon of reduced evaporation in porous media due to the presence of colloidal particles reported in previous works.
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•Evaporation experiments are performed in a channel of rectangular cross-section.•Corner liquid films are observed both without and with colloidal particles.•Particle accumulation in corner film induces film thinning.•Corner film thinning explains slower evaporation in the presence of colloïdal particles.
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