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SSRN 2023年

作者： Cao, Liang Tan, Zhifei Shi, Feiting Liu, Jihang Cao, Peng Wang, Jianru Faculty of Architecture Civil and Transportation Engineering Beijing University of Technology Beijing100124 China Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong Civil Engineering Department Yancheng Institute of Technology Yancheng224051 China College of Control Science and Engineering Bohai University Liaoning Province Jinzhou China The 41st Institute of the Fourth Research Academy of CASC Xian710025 China

Electrochemical testing is effective approach for characterizing the mechanical properties of cementitious materials, but their application to air-entrained concrete is limited. In this study, air-entrained mortar samples with different bubbles were prepared by incorporating varying dosages of air-entraining admixtures (AEA), and their electrochemical properties were measured using two commonly used techniques: electrical resistivity and electrochemical impedance spectroscopy (EIS). To account for the bubble effect, a novel equivalent circuit (EC) model was developed to analyze the EIS data. Results showed that bubbles have insulator properties and significantly increase the direct current electrical resistivity (ρ) and the bulk electrical resistivity (ρbulk) of the mortars. The developed EC model accurately fits the test results in Nyquist plots. Additionally, a back propagation (BP) neural network model was developed to establish a correlation between electrochemical and mechanical properties of air-entrained mortars at different curing times and AEA dosages. The predicted values were found to be highly correlated with the measured values. Furthermore, microscopic tests were conducted on air-entrained mortar, revealing that the insulator property of the bubbles incorporated by AEA is primarily related to the formation of bubble shells. The formation of the bubble shell is related to the barrier effect of the bubble film and the promotion and delay of the hydration of Ca3Al2O6 and Ca3SiO5 by the sulfonate. The findings of this study can be applied to predict the mechanical properties of air-entrained mortar in practical engineering. © 2023, The Authors. All rights reserved.

关键词： Electrochemical impedance spectroscopy

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Fresh and Hardened Properties of 3d Printed Cement Composite Incorporated with Metakaolin

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SSRN 2022年

作者： Duan, Zhenhua Li, Lei Yao, Qinye Zou, Shuai Singh, Amardeep Yang, Haifeng Department of Structural Engineering Tongji University Shanghai200092 China Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong School of Civil Engineering and Architecture Changzhou Institute of Technology Jiangsu213032 China Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi University China

3D concrete printing (3DCP) has received increasing worldwide attentions, however, incorporating metakaolin (MK) as supplementary cementitious materials (SCMs) for rheology modification to develop 3D printed cement composites (3DPCC) is very limited. In this study, the effect of MK was studied from the perspectives of both fresh and hardened properties. Results showed that compared with control, static yield stress, dynamic yield stress, and viscosity increase by 285.4%, 129.5%, and 49.2% with 10% MK. Moreover, the increase in the thixotropic area showed that the addition of MK improves the structuration, which helps in the thixotropic build-up. The addition of MK decreased the fluidity and consistency while increasing the penetration depth resistance of the 3DPCC. Meanwhile, the specimens added with MK exhibited increased maximum stress and elastic modulus under unconfined compression, indicating that MK could enhance the early performance of the 3DPCC, and the higher the amount, the more noticeable the improvement. Moreover, the stiffness development process of 3DPCC was observed from its failure pattern at fresh state, and MK was found to accelerate the failure pattern change from plastic failure to shear failure. Besides, MK also showed improved 3DPCCs' mechanical properties and the inhibition of the drying shrinkage because of its pozzolanic activity and filling effect. It is believed that MK positively affects both fresh and hardened properties of the 3DPCC and is therefore recommended as SCMs to be utilized in 3DCP. © 2022, The Authors. All rights reserved.

关键词： Composite materials

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Optimization of radio frequency assisted freezing and its effects during cooking 6

Optimization of radio frequency assisted freezing and its ef...

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6th IIR Conference on Sustainability and the Cold Chain, ICCC 2020

作者： Anese, Monica Alongi, Marilisa Cortella, Giovanni Manzocco, Lara University of Udine Department of Agricultural Food Environmental and Animal Sciences Udine33100 Italy University of Udine Polytechnic Department of Engineering and Architecture Udine33100 Italy

ISBN: (纸本)9782362150364

A freezing pilot plant combining cryogenic flow and radiofrequency (RF) (2-6 kV) was used to freeze pork meat. Air and liquid nitrogen freezing were also carried out as controls. Differently frozen samples were thawed and submitted to oven cooking. After each operation, samples were analysed for colour, drip loss, and mechanical properties. Although colour and firmness of thawed and cooked meat were not affected by the freezing procedure, the application of RF significantly decreased drip loss with best performance at low RF voltage. It was inferred that the water dipole rotation induced by RF allowed controlling ice crystal size and distribution within meat tissue, leading to better quality properties. © 2020 International Institute of Refrigeration. All rights reserved.

关键词： Freezing

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A Research Framework on Geometric Characterization in Architectural Structures Using Classification Algorithms and Convolutional Networks in the Construction of Processes in Hbim

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SSRN 2024年

作者： Moyano, Juan José Musicco, Antonella Nieto-Julián, Juan E. Domínguez-Morales, Juan Pedro University of Seville Department of Graphical Expression and Building Engineering Ave. Reina Mercedes 4A Seville41012 Spain Department of Civil Environmental Land Construction and Chemistry University Polytechnic of Bari Via Edoardo Orabona 4 Bari70126 Italy Robotic and Technology of Computers Lab Department of Architecture and Technology of Computers University of Seville Av. Reina Mercedes s/n Seville41012 Spain

Building information models (BIM) have become a potential in information management and 3D representation. Thus, the path of knowledge about historical buildings puts the wealth of semantic information and the potential for precision for replicas of complex architectural structures at the service of researchers. The generation of BIM models from the cloud of points in historic buildings represents one of the most important challenges in the scientific community, since the complexity of the use of algorithms is combined with the complexity of the forms that occur in the architecture. . In this context, new Artificial Intelligence (AI) technologies emerge capable of automatically classifying point clouds, but the answer to solving this challenge is far from an effective procedure. To advance this knowledge, a comparison framework is established between two machine learning (ML) methodologies and a deep learning (DL) developer. © 2024, The Authors. All rights reserved.

关键词： Information management

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Effect of Thermal Mass on the Cooling Load of a Well-Insulated Office Building with Radiant Cooling System 11th

Effect of Thermal Mass on the Cooling Load of a Well-Insulat...

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11th International Symposium on Heating, Ventilation and Air Conditioning, ISHVAC 2019

作者： Hu, Rong Niu, Jianlei School of Architecture and Traffic Engineering Guilin University of Electronic Technology Guangxi China Department of Building Services Engineering The Hong Kong Polytechnic University Hong Kong School of Architecture Design and Planning School of Civil Engineering The University of Sydney Sydney Australia

ISBN: (纸本)9789811395277

The effects of thermal mass on the indoor environment and energy consumption of convective air systems (CASs) have been well studied. Few research refers to the corresponding effects in the zone with radiant heating/cooling system. This article aims to study the effects of thermal mass in external walls on the transmission load and energy performance in the spaces with active cooling surfaces, compared with those in identical rooms equipped only with equivalent CASs. This study is based on the investigation of energy performances in an assumed typical office building using the EnergyPlus simulation software. The weather conditions in four typical days during the cooling season in two cities (i.e., Beijing and Nanjing) are considered. The inside massive layer has positive effects on indoor temperature performance and instantaneous transmission load, but little impact on energy consumption. The peak cooling load in the zone with heavyweight can be shifted in a proper operation strategy. Although the cooling surface reduces the effect of thermal mass to radiation heat transfer and enhances the conduction heat gain, a structure with an inside massive layer is recommended in the zone with cooling surface. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Cooling

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The modelling of multiple leaf masonry walls of the arquata del tronto fortress as a non-smooth dynamical system 11

The modelling of multiple leaf masonry walls of the arquata ...

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11th International Conference on Structural Dynamics, EURODYN 2020

作者： Ferrante, Angela Giordano, Ersilia Clementi, Francesco Sarhosis, Vasilis Milani, Gabriele Lenci, Stefano Department of Civil and Building Engineering and Architecture Polytechnic University of Marche via Brecce Bianche Ancona60131 Italy School of Civil Engineering University of Leeds LeedsLS2 9JT United Kingdom Department of Architecture Built Environment and Construction Engineering ABC Polytechnic of Milano Piazza Leonardo da Vinci 32 Milan20133 Italy

ISBN: (纸本)9786188507210

In the present paper has been reported the Non-Smooth Contact Dynamics method (NSCD) used for the damage evaluation of the multiple leaf masonry walls of the medieval fortress of Arquata del Tronto, strongly affected by the last Centre Italy earthquakes of August and October 2016. Pursuing this approach, a system of rigid blocks has been used for the assembly of the masonry structure. By means of contacts between blocks, which are governed by the Signorini's impenetrability condition and by dry-friction Coulomb's law, the building exhibits discontinuous dynamics. Finally, the NSCD method has proved to be an effective instrument for investigating the dynamical behaviour of the masonry structures under the ground seismic accelerations. Indeed, several possible failure mechanisms have been confirmed through the numerical results, which have given a deep insight into the seismic vulnerability of this damaged medieval fortress. © 2020 European Association for Structural Dynamics. All rights reserved.

关键词： Walls (structural partitions)

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Analytical Modelling and Control of Dual Active Bridge Converter Considering all Phase-Shifts 12

Analytical Modelling and Control of Dual Active Bridge Conve...

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12th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2020

作者： Fiaz, Muhammad Faisal Calligaro, Sandro Petrella, Roberto Free University of Bolzano-Bozen Faculty of Science and Technology Bolzano-Bozen Italy University of Udine Polytechnic Department of Engineering and Architecture Udine Italy

ISBN: (数字)9781728158266

ISBN: (纸本)9781728158266

The Dual Active Bridge (DAB) is one of the most promising topologies among bidirectional isolated DC-DC converters, especially in interfaces to batteries. It is recently gaining interest due to its versatile features. The investigative studies are progressing to inspect, control and improve the overall performance of the DAB converter. Currently, there are challenges regarding the control of DAB. It has complex nonlinear properties and also has to attain multiple aims (e.g. regulating power flow, achieving zero voltage switching (ZVS) and minimizing current stresses).This has resulted in the requirement to investigate with different abstraction levels in DAB design process, e.g. ideal behavior (steady-state, dynamics), losses analysis, optimization of parameters and control. In this paper, an accurate analytical model is presented which makes the design of voltage controller simple and independent of the operating conditions. The analytical developments presented, based on the superposition principle, allow obtaining the waveforms of inductor and output current using a simple and fast closed-form procedure. This allows to apply optimization methods for the selection of the operating point or during the design stage (e.g. for selecting inductance and frequency values). Moreover, the novel fully analytical model describes the output current vs. phase-shifts relation. As a study-case, the Single Phase-Shift (SPS) is used for regulating the output current (average) in an open-loop control (by linearizing the control of DAB output voltage. Simulations in PLECS Blockset validate the theoretical results. © 2020 IEEE.

关键词： Zero voltage switching

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Nonlinear Deterministic Observer for Inertial Navigation using Ultra-wideband and IMU Sensor Fusion

arXiv

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arXiv 2023年

作者： Hashim, Hashim A. Eltoukhy, Abdelrahman E.E. Vamvoudakis, Kyriakos G. Abouheaf, Mohammed I. The Department of Mechanical and Aerospace Engineering Carleton University OttawaONK1S 5B6 Canada The Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hung Hum Hong Kong The Daniel Guggenheim School of Aerospace Engineering Georgia Institute of Technology AtlantaGA30332 United States The College of Technology Architecture & Applied Engineering Bowling Green State University Bowling GreenOH43403 United States

Navigation in Global Positioning Systems (GPS)denied environments requires robust estimators reliant on fusion of inertial sensors able to estimate rigid-body's orientation, position, and linear velocity. Ultra-wideband (UWB) and Inertial Measurement Unit (IMU) represent low-cost measurement technology that can be utilized for successful Inertial Navigation. This paper presents a nonlinear deterministic navigation observer in a continuous form that directly employs UWB and IMU measurements. The estimator is developed on the extended Special Euclidean Group SE2 (3) and ensures exponential convergence of the closed loop error signals starting from almost any initial condition. The discrete version of the proposed observer is tested using a publicly available real-world dataset of a drone flight. Copyright © 2023, The Authors. All rights reserved.

关键词： Global positioning system

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Full-scale Dynamic Tests on Unreinforced and GFRCM-reinforced Apulian Tuff Masonry Arches

Full-scale Dynamic Tests on Unreinforced and GFRCM-reinforce...

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2020 IMEKO TC-4 International Conference on Metrology for Archaeology and Cultural Heritage, MetroArchaeo 2020

作者： Castellano, Anna Fraddosio, Aguinaldo Scacco, Jacopo Milani, Gabriele Piccioni, Mario Daniele Department of Civil Engineering Sciences and Architecture Polytechnic University of Bari Via Orabona 4 Bari70125 Italy Department of Architecture Built environment and Construction engineering ABC Politecnico di Milano Piazza Leonardo da Vinci 32 Milan20133 Italy

The study of the dynamic behavior of masonry arches and vaults is of paramount importance for several reasons: the evaluation of the seismic capacity;the determination of failure modes;the determination of the ductility and of behavior factors;the design of effective strengthening interventions, like for example by employing Fiber Reinforced Cementitious Matrix (FRCM) composites. Despite this, the literature still lacks a sufficiently large number of contributions on this subject, especially for what concerns either experimental study or reinforced arches. In this context, this paper, starting from the data of full-scale dynamic tests performed on unreinforced and Glass-FRCM reinforced Apulian tuff masonry arches, proposes some interesting observations on the dynamic behavior of masonry arches. © 2020 IMEKO TC-4 International Conference on Metrology for Archaeology and Cultural Heritage. All rights reserved.

关键词： Arches

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Exploiting multi-camera constraints within bundle block adjustment: An experimental comparison 24

Exploiting multi-camera constraints within bundle block adju...

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2021 24th ISPRS Congress Commission II: Imaging Today, Foreseeing Tomorrow

作者： Maset, E. Rupnik, E. Pierrot-Deseilligny, M. Remondino, F. Fusiello, A. Dept. of Agricultural Food Environmental and Animal Sciences University of Udine Udine Italy LASTIG Univ. Gustave Eiffel ENSG IGN Saint-MandeF-94160 France Trento Italy Polytechnic Department of Engineering and Architecture University of Udine Udine Italy

The growing deployment of multi-head camera systems encouraged the emergence of specific processing algorithms, able to face the challenges posed by slanted view geometry. Such multi-camera systems are rigidly tied by their manufacturers hence the exploitation of this internal constraint should be further exploited. Several approaches have been proposed to deal with orientation constraints, with the aim of reducing the number of unknowns, computational time and possibly improve the accuracy. In this paper we compare the results provided by publicly available implementations in order to further investigate the advantages of enforcing relative orientation constraints for aerial and terrestrial triangulation of multi-head camera systems. Data from a Leica CityMapper and a Stereopolis-Ladybug are considered, reporting how constrained solution can improve accuracy with respect to traditional (unconstrained) bundle block adjustment solutions. © 2021 International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. All rights reserved.

关键词： Cameras

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