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4th International Symposium on New Metropolitan Perspectives, NMP 2020

作者： Salvo, Francesca Morano, Pierluigi De Ruggiero, Manuela Tajani, Francesco Department of Environmental Engineering University of Calabria RendeCS Italy Department of Civil Engineering Science and Architecture Polytechnic University of Bari Bari Italy Department of Architecture and Design Sapienza University of Rome Rome Italy

ISBN: (纸本)9783030482787

Environmental health studies are a really central topic in the debate about territorial development. Territorial transformation was sometimes characterized by interesting phenomena of enhancement and requalification, sometimes by speculative tensions inattentive to the quality of life systems and to the sustainability of processes by territory itself. This kind of attitude has often caused an environmental health decay and a significant decrease in human quality life. The main obstacle to the possibility of orienting the transformation initiatives of the territory in the perspective of sustainability is to be found in the scarce ability to understand the intrinsic economic value that these operations incorporate. We are now used to thinking exclusively in terms of market and income, so territorial interventions are almost guided exclusively by economic evaluations of and speculative ones. In a transdisciplinary perspective, the appraisal analysis can provide an important interpretation key in the analysis of territorial dynamics, intended to guide urban development policies in the logic of sustainability. This paper intends to study some environmental feedbacks in coastal areas and to demonstrate how real estate prices can be used as a marker of environmental health, examining relationships between real estate prices and environmental variables through the use of the Hedonic Model. The hypothesis has been validated by the application of the proposed methodology to a case study in Fuscaldo, in the south of Italy. The results show a correlation between environmental health and real estate prices, proving that an excessive urbanization and a poor attention to environmental issues lead to a decrease in human quality life. © Springer Nature Switzerland AG 2021.

关键词： Sustainable development

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Experimental Damage Identification in Masonry Structures by OMA

Experimental Damage Identification in Masonry Structures by ...

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Metrology for Living Environment (MetroLivEn), IEEE International Workshop on

作者： David Bru Salvador Ivorra Domenico Camassa Department of Civil Engineering University of Alicante San Vicente del Raspeig Spain Department of Civil Engineering Sciences and Architecture Polytechnic University of Bari Bari Italy

This paper presents a study carried out in different types of masonry structures to identify existing damage through dynamic identification techniques using operational modal analysis. A cross vault, a masonry wall and a simple clay brick construction have been analyzed. The three cases have been tested on a full scale in the laboratory. The cross vault has been subjected to a settlement of one of its supports, the damage has occurred and then it has been repaired by using Textile Reinforced Mortars (TRM). In the case of the wall and the simple construction, the damage has been generalized by means of horizontal loads simulating a seismic action by a cyclic incremental load, after the generation of the damage, it has been repaired using TRM. In all cases, a dynamic identification has been carried out prior to the generation of the damage, after the generation of the damage and later after its repair, finally after a new process of damage the structural health changes have been monitored. In the four phases, an identification of the dynamic characteristics of the structures has been carried out, both main frequencies and damping factor associated with each mode shape. Regarding operational modal analysis, the first vibration modes have been identified. Singular Value Plot have been obtained through the EFDD technique. In general terms, the results of the investigation showed that the effect of cracking generated by both horizontal cyclic loads and vertical displacements located in one of the supports generated a decrease in the vibration frequencies and an increase in the structural damping factors for the different vibration modes. On the other hand, in relation to the effect of the reinforcement techniques employed, the results showed the feasibility of recovering or even slightly increasing the stiffness of the original damaged structure. However, the results for the strengthened structures also showed that the intervention on the damaged structure tended to reduc

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A GPU-ready pseudo-spectral method for direct numerical simulations of multiphase turbulence

arXiv

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arXiv 2024年

作者： Roccon, Alessio Polytechnic Department of Engineering and Architecture University of Udine Udine33100 Italy Institute of Fluid Mechanics and Heat Transfer TU-Wien Vienna1060 Austria

In this work, we detail the GPU-porting of an in-house pseudo-spectral solver tailored towards large-scale simulations of interface-resolved simulation of drop- and bubble-laden turbulent flows. The code relies on direct numerical simulation of the Navier-Stokes equations, used to describe the flow field, coupled with a phase-field method, used to describe the shape, deformation, and topological changes of the interface of the drops or bubbles. The governing equations – Navier-Stokes and Cahn-Hilliard equations – are solved using a pseudo-spectral method that relies on transforming the variables in the wavenumber space. The code targets large-scale simulations of drop- and bubble-laden turbulent flows and relies on a multilevel parallelism. The first level of parallelism relies on the message-passing interface (MPI) and is used on multi-core architectures in CPU-based infrastructures. A second level of parallelism relies on OpenACC directives and cuFFT libraries and is used to accelerate the code execution when GPU-based infrastructures are targeted. The resulting multiphase flow solver can be efficiently executed in heterogeneous computing infrastructures and exhibits a remarkable speed-up when GPUs are employed. Thanks to the modular structure of the code and the use of a directive-based strategy to offload code execution on GPUs, only minor code modifications are required when targeting different computing architectures. This improves code maintenance, version control and the implementation of additional modules or governing equations. © 2024, CC BY.

关键词： Graphics processing unit

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Untangling the association between urban mobility and urban elements

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地球空间信息科学学报（英文版） 2024年第4期27卷 1071-1089页

作者： Jinzhou Cao Wei Tu Rui Cao Qili Gao Guanzhou Chen Qingquan Li College of Big Data and Internet Shenzhen Technology UniversityShenzhenChina Key Laboratory of National Geographic Census and Monitoring Ministry of Natural ResourcesWuhan UniversityWuhanChina School of Architecture and Urban Planning & Guangdong Key Laboratory of Urban Informatics Shenzhen UniversityShenzhenChina Department of Land Surveying and Geo-Informatics & Smart Cities Research Institute The Hong Kong Polytechnic UniversityHong KongChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan UniversityWuhanChina

Understanding complex urban systems necessitates untangling the relationships between diverse urban elements such as population,infrastructure,and socioeconomic *** laws are basic but effective rules for evaluating a city's internal growth logic and assessing its efficiency by investigating whether urban indicators scale with *** date,only limited research has empirically explored the scaling relations between variables of urban mobility in mega-cities at an intra-urban scale of a few *** multiple urban-sensed and human-sensed data,this study proposes a thorough framework for quantifying the scaling laws in a *** begin,urban mobility networks are built by aggregating population flows using large-scale mobile phone tracking *** demonstrate the spatiotemporal variability of urban mobility,various network-based mobility measures are *** that,three different features of urban mobility laws are exposed,explaining spatial agglomeration,spatial hierarchical structures,and the temporal growth *** scaling correlations between urban indicators pertaining to socioeconomic features and infrastructure and a mobility-population measure are then quantified using multi-sourced urban-sensed *** this framework to the case study of Shenzhen,China revealed(a)spatial travel heterogeneity,hierarchical spatial structures,and mobility growth,and(b)not only a robust sub-linear relationship between infrastructure volume and population,but also a sub-linear relationship for socioeconomic *** identified scaling laws,both in terms of mobility measures and urban indicators,provide a multi-faceted portrait of the spatio-temporal varia-tions of urban settings,allowing us to better understand intra-urban developments and,consequently,provide critical policy evaluations and suggestions for improving intra-urban efficiency in the future.

关键词： Scaling law urban scaling urban mobility intra-urban system mobile phone data

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ASSESSMENT OF TRAFFIC SIGN RETROREFLECTIVITY FOR AUTONOMOUS VEHICLES: A COMPARISON BETWEEN HANDHELD RETROREFLECTOMETER AND LIDAR DATA

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Archives of Transport 2024年第2期70卷 7-26页

作者： Aldoski, Ziyad N. Koren, Csaba Department of Highway and Bridge Technical College of Engineering Duhok Polytechnic University Mazi Qr Duhok Kurdistan Iraq Department of Transport Infrastructure and Water Resources Engineering Faculty of Architecture Civil Engineering and Transportation Sciences Széchenyi István University Győr Hungary

This study investigates the critical role of retroreflectivity in traffic signs, particularly in the context of autonomous vehicles (AVs), where accurate detection is paramount for road safety. Retroreflectivity, influencing visibility and legibility, is essential for ensuring safe road conditions. The study aims to assess traffic sign retroreflectivity using handheld retroreflectometers and LiDAR data, offering a comprehensive comparison of results with a specific focus on the RA1 and RA2 traffic sign classes. In a real-world setting, an AV equipped with LiDAR sensors, GPS units, and a stereo camera collects data on traffic signs, including point cloud attributes such as intensity and density. Simultaneously, a handheld retroreflectometer measures retroreflectivity coefficients from identified traffic signs. While retroreflectometers provide precision, they face limitations regarding time-consuming measurements and handling large or elevated signs. In contrast, LiDAR systems efficiently evaluate retroreflective features for numerous signs without such constraints. Despite both methods consistently yielding accurate retroreflectivity, the study reveals a limited correlation between LiDAR point cloud data and handheld retroreflectivity coefficients. The implications of these findings are significant, particularly in the selection and maintenance of retroreflective materials in traffic signs, with direct repercussions on overall road safety. The results offer valuable insights into leveraging LiDAR technology to enhance AVs' detection capabilities. Recommendations for further research include exploring factors influencing LiDAR intensity, establishing a more accurate relationship between intensity and retroreflectivity, correcting the point cloud during intensity calibration, and testing empirical prediction models with a larger sample size. These endeavors aim to generate a robust regression graph and determine correlation coefficients, providing a more nuanced under

关键词： Autonomous vehicles

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Continuous and discontinuous descriptions of blocked structures: The case study of Santissimo Crocifisso Church in Pretare (Italy) 8

Continuous and discontinuous descriptions of blocked structu...

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8th International Conference on Computational Methods in Structural Dynamics and Earthquake engineering, COMPDYN 2021

作者： Clementi, F. Ferrante, A. Giordano, E. Lenci, S. Department of Civil and Building Engineering and Architecture Polytechnic University of Marche via Brecce Bianche Ancona60131 Italy

Advanced numerical modelling of the masonry "Apennine Church" of Santissimo Crocifisso in Pretare, Arquata del Tronto (AP), was here utilized to have an insight into the dynamic properties and behavior of the structure under strong nonlinear dynamic excitations. The objectives were achieved by comparing nonlinear dynamic analyses through discontinuous and continuous approaches. In the discrete element approach, the Non-Smooth Contact Dynamics method, implemented in LMGC90©, was applied, adopting a full 3D detailed discretization. The Church was schematized as an arrangement of discrete rigid blocks, subjected to sliding by friction and perfect plastic collisions, governed by Signorini's impenetrability condition and dry-friction Coulomb's law, with a null restitution coefficient. In the finite element approach, the Concrete Damaged Plasticity model available in Midas FEA NX© was involved. This model allows reproducing the tensile cracking, the compressive crushing, and the degradation of the material under cyclic loads. At the end, the structure exhibited a complex dynamic behavior, because of the geometrical nonlinearity and the non-smooth nature of the contact laws. Finally, the numerical analyses provided a valuable picture of the actual behavior of the church, which is mandatory for future strengthening interventions. © 2021 COMPDYN Proceedings.

关键词： Friction

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Effect of Surface Finish on Fatigue Properties of Ti Gr23 Alloy Produced by L-PBF and to Be Used for Human Implants

Effect of Surface Finish on Fatigue Properties of Ti Gr23 Al...

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International Workshop on engineering Methodologies for Medicine and Sports, EMMS 2024

作者： Lanzutti, Alex Sordetti, Francesco Magnan, Michele Picco, Niki Michelon, Fabio Sciarretta, Francesco Roncari, Silvia Zanetti, Cesare Pennè, Wanda Marin, E. Fedrizzi, Lorenzo Polytechnic Department of Engineering and Architecture Udine University University of Udine Via Delle Scienze 208 Udine33100 Italy GPI Spa Via Ragazzi del 99 13 TN Trento38123 Italy Biomedical Research Center Kyoto Institute of Technology Sakyo-Ku Kyoto Matsugasaki606-8585 Japan

ISBN: (纸本)9783031637544

Ti Gr23 alloys are widely used in the manufacture of human implants and have recently been produced by L-PBF (Laser Powder Bed Fusion) techniques due to their good mechanical properties combined with good biocompatibility. The fatigue properties of these components are very important and are influenced by many parameters such as: surface finish, residual stresses and internal defects. This paper presents a detailed study of the effect of surface finish on the fatigue properties of Ti-Gr23 alloy produced by L-PBF. In this case, the samples are all produced in the vertical direction using two different LASER conditions. One part of the specimens was analysed under as-built conditions, one part was sandblasted and the last part was manually polished. The surface texture was then analysed using a stylus profilometer. Mechanical properties were then assessed by tensile tests and microhardness profiles acquired on specimens used for mechanical testing. Fatigue tests were then carried out under load control at R = −1 with a frequency of 40 Hz, starting from an initial stress of 40% of the tensile strength of the material. The fatigue limit was calculated using the Dixon Mood approach. A detailed SEM analysis of the fracture surface was carried out to determine the causes of failure in the failed specimens. The results obtained were then used to evaluate the local fatigue limit near the crack nucleation site using the Murakami model. The results showed an improvement in the fatigue properties of the surface treated specimens compared to the untreated specimens. No differences were observed in the effect of the LASER conditions. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： 3D printing

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Experimental investigation on the effect of the Fused Deposition Modeling parameters on the processing of Polyether Ether Ketone

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Journal of Materials Research and Technology 2025年 36卷 8007-8021页

作者： Erica Billè Marina Franulović Alessandro Gambitta David Liović Alfredo Rondinella Federico Scalzo Marco Sortino Giovanni Totis Emanuele Vaglio Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 Udine 33100 Italy University of Rijeka Faculty of Engineering Vukovarska 58 Rijeka 51000 Croatia Elettra-Sincrotrone Trieste Area Science Park Basovizza Trieste 34149 Italy

The use of Fused Deposition Modeling to produce high-performance polyether ether ketone is steadily increasing. However, the limited availability of in-depth studies on the process hampers its potential for industrial and scientific applications. This study investigates how nozzle temperature, nozzle speed, and layer thickness influence crucial product properties, including surface roughness, dimensional accuracy, and mechanical behavior, by means of Confocal and Scanning Electron Microscopy, X-ray Micro-Computed Tomography, Fourier-Transform Infrared Spectroscopy, Energy-Dispersive X-ray Spectroscopy, tensile and hardness tests. Selected samples were further analyzed in exceptional detail by synchrotron radiation, while degassing behavior in Ultra-High Vacuum conditions was explored for optimal configurations. The results highlight the critical influence of process parameters on the final properties of FDM-printed PEEK parts. Nozzle temperature proved to be the most significant factor in improving both mechanical performance and surface finish, while nozzle speed predominantly affected dimensional accuracy. Layer thickness had a secondary effect, mainly influencing surface roughness and contributing to internal defects and variability in mechanical properties. The combination of parameters that yielded the most balanced performance was identified as a nozzle temperature of 420 °C, nozzle speed of 40 mm/s, and layer thickness of 0.1 mm. Across all tested configurations, the maximum Ultimate Tensile Strength achieved was 84 MPa, while the highest recorded part density reached 99.8%. These outcomes enabled the successful manufacturing of components suitable for ultra-high vacuum environments. The process was validated through the fabrication of a benchmark part with complex geometries, demonstrating the capability of FDM to produce high-precision, high-performance components.

关键词： Additive manufacturing Fused deposition modeling PEEK Process parameters optimization

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Regulating the electronic structure of Ir single atoms by ZrO_(2)nanoparticles for enhanced catalytic oxidation of formaldehyde at room temperature

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Chinese Chemical Letters 2024年第7期35卷 200-205页

作者： Shiqi Peng Yongfang Rao Tan Li Yufei Zhang Jun-ji Cao Shuncheng Lee Yu Huang Key Laboratory of Aerosol Chemistry&Physics State Key Laboratory of Loess and Quaternary Geology(SKLLQG)Institute of Earth EnvironmentChinese Academy of Sciences(CAS)Xi’an 710061China School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China Department of Environmental Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China Faculty of Chemical Engineering Kunming University of Science and TechnologyKunming 650500China School of Environment and Energy South China University of TechnologyGuangzhou 51006China School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100190China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong KongChina CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China

Developing low-loading single-atom catalysts with superior catalytic activity and selectivity in formaldehyde(HCHO)oxidation at room temperature remains ***,ZrO_(2)nanoparticles coupled low-loading Ir single atoms in N-doped carbon(Ir_(1)-N-C/ZrO_(2))was *** optimal Ir_(1)-N-C/ZrO_(2)with 0.25 wt%Ir loading delivers the high HCHO removal and conversion efficiency(>95%)at 20℃,which is higher than that over Ir_(1)-N-C with the same Ir *** specific rate can reach 1285.6 mmol gIr^(-1)h^(-1),surpassing the Ir based catalysts reported to *** functional theory calculation results and electron spin resonance spectra indicate that the introduction of Zr O_(2)nanoparticles modulate the electronic structure of the Ir single atoms,promoting O_(2)activation to·O_(2)^(–).Moreover,the Ir-C-Zr channel is favorable for the dissociation of·O_(2)^(–)to active oxygen atom(*O),and further accelerates the transformation of HCHO and intermediates(dioxymethylene and formates)to CO_(2)and H_(2)*** work provides a facile strategy to design low-loading single-atom catalysts with high catalytic activity toward HCHO oxidation.

关键词： ZrO_(2)nanoparticles Ir single atoms Electronic structure Formaldehyde Catalytic oxidation

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Analytical and Numerical Study of the Hydro-Mechanical Behavior of a Cantilever Retaining Wall in Upward Seepage Conditions

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World Journal of engineering and Technology 2024年第4期12卷 914-937页

作者： Mbuh Moses Kuma Nsahlai Leonard Penka Jules Bertrand Kouamou Nguessi Arnaud Tchemou Gilbert Agandeh Elvis Phonchu Claret Abong Department of Civil Engineering and Forestry Techniques Higher Technical Teacher Training College University of Bamenda Bamenda Cameroon Department of Civil Engineering and Architecture The National Higher Polytechnic Institute (NAHPI) of the University of Bamenda Bamenda Cameroon Mechanics Laboratory ENSET of the University of Douala Douala Cameroon

Poor design of ground water evacuation mechanisms is often blocked and leads to the rise of ground water behind the wall. As a result, free water behind the wall that is not quickly evacuated, increases the lateral pressure and thus favors overturning failure. The resolution of the overturning problem in cantilever retaining walls caused by hydro-mechanical interaction was studied. An analytical and numerical method was used to study this type of wall-floor interaction. Then Coulomb’s design criterion against overturning to develop a mathematical model that compute analytical factor of safety against overturning in different water conditions and heel lengths was used. The modeling and simulation of this system in the Cast3m software which took into account a wide variety of floor and wall properties were performed. The numerical factor of safety against rollover was obtained, and the graphs for the factor of safety versus heel length and immersion depth for both methods were plotted. From (0 ≤ Hw ≤ H/3), water effect is not dangerous to wall stability against overturning and from (H/3 Hw ≤ H), water effect is very dangerous to wall stability against overturning. For analytical and numerical methods, the heel can be predimensioned against overturning as: Lc: [0.27H 0.38H], [0.29H 0.43H] for 0 ≤Hw ≤ H/3;[0.33H 0.45H], [0.39H 0.53H] for H/3 Hw ≤ 2H/3;[0.5H 0.6H], [0.50H 0.67H] for 2H/3 Hw≤ H. The numerical method guaranteeing more safety than the analytical method, Cantilever retaining walls can thus be pre-dimensioned considering Clayey-Sand soil in hydro-mechanical conditions.

关键词： Cantilever Retaining Wall Overturning Hydro-Mechanical Soil-Structure Interaction

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