检索结果-内蒙古大学图书馆

Towards the Scale-Up of Solid-State, Low-Emissive Electrochromic Films with Novel Electrolyte Formulations, Fabricated at Room Temperature

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Cannavale, Alessandro Pugliese, Marco Giannuzzi, Roberto Scarfiello, Riccardo Prontera, Carmela Tania Primiceri, Vitantonio Mazzeo, Marco Martellotta, Francesco Ayr, Ubaldo Fiorito, Francesco Mariano, Fabrizio Maggiore, Antonio Maiorano, Vincenzo Gigli, Giuseppe Department of Civil Engineering Sciences and Architecture Polytechnic University of Bari Bari Italy Via Monteroni Lecce73100 Italy Department of Civil Environmental Land Building Engineering and Chemistry Polytechnic University of Bari Bari Italy Department of Mathematics and Physics "Ennio De Giorgi"- University of Salento Lecce73100 Italy

This experimental work reports the activities of design, fabrication and characterization of an innovative solid-state electrochromic device, deposited on a single substrate with high transparency in the bleached conditions and a wide modulation (ΔT of 60% at 750 nm) both in the visible and near-infrared wavelengths. A tailored formulation of the solid electrolytes, based on sulfonated tetrafluoroethylene-based fluoropolymer-copolymer dispersions and the accurate design of a suitable layer of porous tin oxide nanoparticles provided high coloration and bleaching kinetics and recovery of the pristine conditions, even after 500 complete cycles. Devices were scaled-up to 10x10 cm 2 size, without mechanical and aesthetic defects and relevant homogeneity, throughout the coloration and bleaching processes. Furthermore, this device shows the further feature to be a low-emissivity dynamic solar control film, highly compatible with integration within insulated glazed units. © 2022, The Authors. All rights reserved.

关键词： Electrochromism

An efficient active-stress electromechanical isogeometric shell model for muscular thin film simulations

学校读者我要写书评

暂无评论

arXiv

arXiv 2024年

作者： Torre, Michele Morganti, Simone Nitti, Alessandro de Tullio, Marco Donato Kiendl, Josef Pasqualini, Francesco Silvio Reali, Alessandro Department of Civil Engineering and Architecture University of Pavia via Ferrata 3 Pavia27100 Italy Department of Electrical Computer and Biomedical Engineering University of Pavia via Ferrata 5 Pavia27100 Italy Department of Mechanics Mathematics and Management Polytechnic University of Bari Via Re David 200 Bari70125 Italy Institute of Engineering Mechanics and Structural Analysis Bundeswehr University Munich Werner-Heisenberg-Weg 39 Neubiberg85577 Germany

We propose an isogeometric approach to model the deformation of active thin films using layered, nonlinear, Kirchhoff–Love shells. Isogeometric Collocation and Galerkin formulations are employed to discretize the electrophysiological and mechanical sub-problems, respectively, with the possibility to adopt different element and time-step sizes. Numerical tests illustrate the capabilities of the active-stress-based approach to effectively simulate the contraction of thin films in both quasi-static and dynamic conditions. © 2024, CC BY-NC-ND.

关键词： Thin films

Multiscale Characterization and Modeling of Aggregate Contact Effects on Asphalt Concrete's Tension-Compression Asymmetry

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Tan, Zhifei Yang, Bin Jelagin, Denis Leng, Zhen Cao, Peng Li, Rui Zou, Fuliao Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hong Kong Department of Civil and Architectural Engineering KTH Royal Institute of Technology Brinellvägen 23 Stockholm10044 Sweden College of Architecture and Civil Engineering Beijing University of Technology Beijing China National & Local Joint Engineering Research Center of Transportation and Civil Engineering Materials Chongqing Jiaotong University Chongqing China

Asphalt concrete (AC) exhibits significant tension-compression (TC) asymmetry and aggregate contacts can be one of the critical contributors to this behavior. Nevertheless, the underlying mechanisms are still unclear, and there has been no study to quantify this behavior. To fill the research gap, multiscale characterization and modeling on AC were performed in this study. At the microscale level, nanoindentation tests were conducted to characterize the aggregate contact characteristics in the contact region (CR). It was found that the CR has a sandwich-like structure composed of two stiffened interfacial layers, large filler particles and asphalt mastic. Accordingly, the micromechanical models of CR were developed to predict its mechanical behavior in T&C. The modeling results showed that aggregate contacts significantly increase the compressive modulus, leading to the substantial TC asymmetry of CR. The predicted viscoelastic properties of CR were further applied to the developed mesostructural model of AC. The predicted master curves in T&C showed significant asymmetry and quantitatively agreed with the experimental ones, demonstrating the effectiveness of the adopted modeling approaches. This study is the first study to quantify the asymmetric performance of AC. The outcomes of this study can be applied to evaluate AC’s TC asymmetry effects on pavement performance. © 2023, The Authors. All rights reserved.

关键词： Finite element method

The non-smooth dynamics of multiple leaf masonry walls of the arquata del tronto fortress 24th

学校读者我要写书评

暂无评论

The non-smooth dynamics of multiple leaf masonry walls of th...

24th Conference of the Italian Association of Theoretical and Applied Mechanics, AIMETA 2019

作者： Clementi, Francesco Ferrante, Angela Lenci, Stefano Department of Civil and Building Engineering and Architecture Polytechnic University of Marche Via Brecce Bianche Ancona60131 Italy

ISBN: (纸本)9783030410568

The progressive damage of the multiple leaf masonry walls of the Arquata del Tronto medieval fortress, inside the epicentral zone of the last Centre Italy earthquakes of August and October 2016, has been investigated by means of the Non-Smooth Contact Dynamics method (NSCD). According to this model, the masonry structure has been modelled as a system of rigid blocks, and since the contacts between blocks are governed by the Signorini’s impenetrability condition and by dry-friction Coulomb’s law, the building exhibits discontinuous dynamics. The NSCD method has proved to be a powerful tool for investigating the dynamics induced by ground seismic accelerations. Indeed, the numerical results have given a deep insight into the seismic vulnerability of this damaged medieval fortress, confirming several possible failure mechanisms. © Springer Nature Switzerland AG 2020.

关键词： Cultural heritage Damage assessment Discrete element method Medieval fortress Multiple leaf walls Non-smooth contact dynamics method

Particles bed morphology under an oscillating stiff and flexible plates 9

学校读者我要写书评

暂无评论

Particles bed morphology under an oscillating stiff and flex...

9th International Conference on Micromechanics on Granular Media, Powders and Grains 2021

作者： Prati, Anna Larcher, Michele Jenkins, James T. La Ragione, Luigi Faculty of Science and Technology Free University of Bozen-Bolzano Bolzano39100 Italy School of Civil and Environmental Engineering Cornell University IthacaNY14853 United States Department of Civil Engineering Sciences and Architecture Polytechnic University of Bari Bari70125 Italy

We analyse the different morphologies induced by an oscillating plate above an erodible bed. We present some data describing how the shape and the stiffness of the plate affects the main features of the generated heap. We investigate several configurations with different geometries, frequencies and the amplitudes. Some preliminary results are available, in which the role of the flexibility of the plate is taken in account. Unlike the rigid plate in which a proper oscillation induces the formation of one heap, the morphology of the bed is now characterized by more than one heap due to a different pressure profile induced by a flexible plate. © The Authors, published by EDP Sciences.

关键词： Morphology

Thermal Respite for Pedestrians in Overheated Urban Environments

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Yu, Yichen de Dear, Richard School of Architecture Design and Planning The University of Sydney NSW Australia Department of Building Environment and Energy Engineering The Hong Kong Polytechnic University Hunghom Kowloon Hong Kong

Superimposition of global warming on urban heat islands is making outdoor cooling infrastructure critical to the maintenance of walkability of many cities. How to optimise placement, operational and functional characteristics of thermal respite (cooling infrastructure) to maximise pedestrians’ thermal comfort is still unclear. In this study the thermal discomfort accumulating during episodic exercise in outdoor heat was analogized as the charging of a capacitor. Skin temperature and core temperature responses were collected from a sample of human subjects (n=24) who were exposed to bouts of simulated urban heat stress, while exercising on an ergometer at an intensity corresponding to the metabolic rate of a brisk walk. Thermal respite (wind, shade, or some combination of both) was provided to the subjects to discharge accumulated heat load after they reached a specific threshold of thermal discomfort. We found that the thermal discomfort capacitor of most subjects (75%) became fully charged (‘pleasant’ → ‘intolerable’) after a 0.4 °C increment in mean body temperature, and its discharge required a 0.7 °C degree-minute decrement in mean skin temperature. The comfort capacitor analogy provides an estimate of the intensity and duration of cooling respite required by pedestrians during brief exposures to overheated urban climates. © 2022, The Authors. All rights reserved.

关键词： Global warming

Determination of the Uncertainty in Measurements of Thermal Conductivity (Λ) of Gypsum Composites Modified by Pcm Using the „Hot Wire" Method

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Janiak, Slawomira Mazurek-Rudnicka, Daria Heim, Dariusz Klementowski, Igor Calisia University Polytechnic Faculty Nowy Świat 4 Kalisz62-800 Poland Department of Environmental Engineering Lodz University of Technology Wolczanska 213 Lodz93-005 Poland Opole University of Technology Faculty of Architecture and Building Katowicka 48 Opole45-061 Poland

The method of estimating the uncertainty for measurement of thermal conductivity (λ) based on conducted experimental investigations was presented in this article. Originally designed and developed the measuring system for determining of thermal conductivity of solid bodies using hot wire method was applied. Due to low costs, high accuracy and short time of measurement, it is a common dynamic technique, effectively used in a transitional states. This method includes measurement of temperature rise from linear source of heat („hot wire") placed in a tested material. The experimental value of the thermal conductivity of the tested composite (gypsum with paraffin and polymer) and values of relative components of standard uncertainties of this parameter were determined. A satisfactory, low value of complex relative extended uncertainty of thermal conductivity U(λ)/λ was obtained. © 2024, The Authors. All rights reserved.

关键词： Heat transfer

Surface Characteristics and Tribological Behaviour of 3d-Printed 316 L Steel after Plasma Assisted Low Temperature Carburizing

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Bolli, Eleonora Kaciulis, Saulius Lanzutti, Alex Mezzi, Alessio Montanari, Roberto Palombi, Alessandra Sordetti, Francesco Vaglio, Emanuele Varone, Alessandra Verona, Claudio ISMN-CNR P.O. Box 10 Monterotondo Stazione Rome00015 Italy Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 208 Udine33100 Italy Department of Industrial Engineering University of Rome "Tor Vergata" Via del Politecnico 1 Roma00133 Italy

To improve the tribological behavior of 316 L steel manufactured by Laser Powder Bed Fusion (L-PBF), low temperature carburizing treatments assisted by plasma have been performed at 475 °C for 7 hours by using gas mixtures (CH4 + H2) with different amounts of CH4. The samples were then submitted to wear tests in pin-on-flat (POF) mode at room temperature with applied loads of 10 N and 20 N. The surface characteristics were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). The results show that plasma treatments induce the formation of a ~25 μm thick layer of expanded austenite (S-phase) that is covered by a diamond like carbon (DLC) over-layer of ~2 μm. Such over-layer exhibits a complex sub-structure: the inner part consists of amorphous C (sp2 bonds) with a degree of topological disorder depending on the gas mixture whereas in the external part both sp2 (graphite-like) and sp3 (diamond-like) bonds are present with relative amounts changing with the distance from the surface. Independently on the gas mixture used in plasma treatment, all the samples exhibit a wear resistance much better than that of the untreated material. Moreover, wear resistance also depends on plasma treatment conditions: the greater the CH4 content, the lower the wear resistance. The results have been discussed by considering the intrinsic DLC brittleness that fractures and detaches from the metal surface during the tests thus hard debris take part to the wear process acting as abrasive particles. © 2023, The Authors. All rights reserved.

关键词： X ray diffraction

Planning optimal minimum-jerk trajectories for redundant robots

学校读者我要写书评

暂无评论

Robotics and Autonomous Systems 2025年 192卷

作者： Lozer, Federico Scalera, Lorenzo Boscariol, Paolo Gasparetto, Alessandro Polytechnic Department of Engineering and Architecture University of Udine Udine33100 Italy Department of Management and Engineering University of Padova Vicenza36100 Italy

In this paper, a minimum-jerk trajectory planning approach for redundant manipulators is presented. The proposed approach leverages not only the optimization of the time intervals between each of the way points of the assigned path, but also the optimal positions of a selected robot joint to reduce the jerk of the robot end-effector. This multi-stage optimization strategy is validated through extensive numerical simulations and experimental tests on a robot with seven degrees of freedom performing a pick-and-place motion. The results of the tests, supported by accelerometer measurements of the vibrations of the robot end-effector, prove the performance of the proposed approach in reducing both the acceleration and the jerk levels of the redundant manipulator in comparison with a state-of-the-art trajectory planning technique. © 2025 The Authors

关键词： Grippers