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  • 1. Anugwom, Ikenna
    et al.
    Lahtela, Ville
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kiljunen, Samantha
    Karki, Timo
    Kallioinen-Manttari, Mari
    Esterified Lignin from Construction and Demolition Waste (CDW) as a Versatile Additive for Polylactic-Acid (PLA) Composites-The Effect of Artificial Weathering on its Performance2022In: Global Challenges, E-ISSN 2056-6646, Vol. 6, no 8, article id 2100137Article in journal (Refereed)
    Abstract [en]

    Demand for sustainable packaging and building materials has increased the need for biobased additives. Biocomposites can often be exposed to different weather conditions and UV irradiation. Thus, additives to prevent the negative impact of weathering are generally added to composites. This study aims to evaluate using esterified lignin as an additive against weathering effects in polylactic-acid (PLA) composites. Lignin is extracted from construction and demolition waste (CDW) wood using a deep eutectic solvent then esterified and tested as an additive in the fabrication of biobased composites. For comparison, lignin from birch is used as a raw material for an additive. Esterification is confirmed by solid-state N MR analysis. Samples are exposed to artificial weathering for 700 hours and their impact strength and color change properties are measured. The results indicate that esterified lignin from CDW (CDW e-lignin) as an additive protects the biocomposite from the weathering impact. The sample containing the CDW e-lignin as an additive suffers only a 4.3% of reduction of impact strength, while the samples that contain commercial additives lose clearly more of their impact strength (from 23.1% to 61.1%). Based on the results CDW e-lignin is a good additive to prevent weathering. As a conclusion, the esterified lignin from CDW, is a versatile additive for composite production.

  • 2.
    Barzegar, Hamid Reza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Department of Physics, University of California, Berkeley, CA 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
    Yan, Aiming
    Coh, Sinisa
    Gracia-Espino, Eduardo
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Ojeda-Aristizabal, Claudia
    Dunn, Gabriel
    Cohen, Marvin L.
    Louie, Steven G.
    Wågberg, Thomas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Zettl, Alex
    Spontaneous twisting of a collapsed carbon nanotube2017In: Nano Reseach, ISSN 1998-0124, E-ISSN 1998-0000, Vol. 10, no 6, p. 1942-1949Article in journal (Refereed)
    Abstract [en]

    We study the collapsing and subsequent spontaneous twisting of a carbon nanotube by in situ transmission electron microscopy (TEM). A custom-sized nanotube is first created in the microscope by selectively extracting shells from a parent multi-walled tube. The few-walled, large-diameter daughter nanotube is driven to collapse via mechanical stimulation, after which the ribbon-like collapsed tube spontaneously twists along its long axis. In situ diffraction experiments fully characterize the uncollapsed and collapsed tubes. The experimental observations and associated theoretical analysis indicate that the origin of the twisting is compressive strain.

  • 3. Challamel, Noel
    et al.
    Girhammar, Ulf Arne
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boundary-Layer Effect in Composite Beams with Interlayer Slip2011In: Journal of Aerospace Engineering, ISSN 0893-1321, E-ISSN 1943-5525, Vol. 24, no 2, p. 199-209Article in journal (Refereed)
    Abstract [en]

    An apparent analytical peculiarity or paradox in the bending behavior of elastic-composite beams with interlayer slip, sandwich beams, or other similar problems subjected to boundary moments exists. For a fully composite beam subjected to such end moments, the partial composite model will render a nonvanishing uniform value for the normal force in the individual subelement. This is from a formal mathematical point of view in apparent contradiction with the boundary conditions, in which the normal force in the individual subelement usually is assumed to vanish at the extremity of the beam. This mathematical paradox can be explained with the concept of boundary layer. The bending of the partially composite beam expressed in dimensionless form depends only on one structural parameter related to the stiffness of the connection between the two subelements. An asymptotic method is used to characterize the normal force and the bending moment in the individual subelement to this dimensionless connection parameter. The outer expansion that is valid away from the boundary and the inner expansion valid within the layer adjacent to the boundary (beam extremity) are analytically given. The inner and outer expansions are matched by using Prandtl's matching condition over a region located at the edge of the boundary layer. The thickness of the boundary layer is the inverse of the dimensionless connection parameter. Finite-element results confirm the analytical results and the sensitivity of the bending solution to the mesh density, especially in the edge zone with stress gradient. Finally, composite beams with interlayer slip can be treated in the same manner as nonlocal elastic beams. The fundamental differential equation appearing in the constitutive law associated with the partial-composite action in a nonlocal elasticity framework is discussed. Such an integral formulation of the constitutive equation encompassing the behavior of the whole of the beam allows the investigation of the mechanical problem with the boundary-element method.

  • 4.
    Fernberg, Johannes
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Micro- / Meso- Scale Dielectric Strength Testing of Fibre Composites2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Glass fibre composites are common materials used in high voltage applications as insulating materials that provide good structural integrity. The aim of this thesis is to develop a method of studying the failure in such materials by measuring the dielectric strength on micro- and meso- scale samples, consisting of single fibre filaments and fibre bundles respectively embedded in epoxy resin. To do this, a body of relevant knowledge has been amassed, which is complemented with finite element analysis giving detailed insight into the electric field distribution in the microstructure of fibre composites. A method of producing virtually defect free single fibre samples has been developed where a filament is hung down tubes and cast in epoxy resin. A similar method was developed for producing bundle samples, however this needs some slight correction in order to prevent exothermic reactions. The dielectric strength of these samples are measured by applying a continuously increasing voltage until discharge is recorded. To evaluate the method micro- and meso- scale samples were prepared of three different fibres and their dielectric strengths measured. This evaluation showed that the method can be used to measure a definitive lower bound in the dielectric strength of fibre composites. However, the method can not definitively determine the location of the discharge, which is necessary to verify conclusions about the materials properties. To progress the method, the dielectric strength of neat epoxy samples of the same dimensions as the fibre composite samples should be investigated. Increasing the tolerance of the measurement setup should also be investigated as this could help by increasing the power of the discharge leading to more severe damage in the material. 

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  • 5.
    Li, Yuanyuan
    et al.
    Department of Fibre and Polymer Technology Wallenberg Wood Science Center, Chemical Science and Engineering Institution KTH Royal Institute of Technology Teknikringen 56–58 Stockholm Sweden.
    Fu, Qiliang
    Department of Fibre and Polymer Technology Wallenberg Wood Science Center, Chemical Science and Engineering Institution KTH Royal Institute of Technology Teknikringen 56–58 Stockholm Sweden.
    Rojas, Ramiro
    Department of Fibre and Polymer Technology Wallenberg Wood Science Center, Chemical Science and Engineering Institution KTH Royal Institute of Technology Teknikringen 56–58 Stockholm Sweden.
    Yan, Min
    School of Engineering Sciences KTH Royal Institute of Technology Isafjordsgatan 22 Stockholm Sweden.
    Lawoko, Martin
    Department of Fibre and Polymer Technology Wallenberg Wood Science Center, Chemical Science and Engineering Institution KTH Royal Institute of Technology Teknikringen 56–58 Stockholm Sweden.
    Berglund, Lars
    Department of Fibre and Polymer Technology Wallenberg Wood Science Center, Chemical Science and Engineering Institution KTH Royal Institute of Technology Teknikringen 56–58 Stockholm Sweden.
    Lignin‐retaining transparent wood2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 17, p. 3445-3451Article in journal (Refereed)
    Abstract [en]

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK−1, and work-tofracture of 1.2 MJ m−3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.

  • 6.
    Liu, Bokai
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Institute of Structural Mechanics, Bauhaus-Universität Weimar, Weimar, Germany.
    Lu, Weizhuo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Zhuang, Xiaoying
    Institute of Photonics, Gottfried Wilhelm Leibniz Universität Hannover, Hannover, Germany.
    Rabczuk, Timon
    Institute of Structural Mechanics, Bauhaus-Universität Weimar, Weimar, Germany.
    Stochastic interpretable machine learning based multiscale modeling in thermal conductivity of Polymeric graphene-enhanced composites2024In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085, Vol. 327, article id 117601Article in journal (Refereed)
    Abstract [en]

    We introduce an interpretable stochastic integrated machine learning based multiscale approach for the prediction of the macroscopic thermal conductivity in Polymeric graphene-enhanced composites (PGECs). This method encompasses the propagation of uncertain input parameters from the meso to macro scale, implemented through a foundational bottom-up multi-scale framework. In this context, Representative Volume Elements in Finite Element Modeling (RVE-FEM) are employed to derive the homogenized thermal conductivity. Besides, we employ two sets of techniques: Regression-tree-based methods (Random Forest and Gradient Boosting Machine) and Neural networks-based approaches (Artificial Neural Networks and Deep Neural Networks). To ascertain the relative influence of factors on output estimations, the SHapley Additive exPlanations (SHAP) algorithm is integrated. This interpretable machine learning methodology demonstrates strong alignment with published experimental data. It holds promise as an efficient and versatile tool for designing new composite materials tailored to applications involving thermal management.

  • 7.
    Liu, Bokai
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Institute of Structural Mechanics, Bauhaus-Universität Weimar, Weimar, Germany.
    Wang, Yizheng
    Department of Engineering Mechanics, Tsinghua University, Beijing, China; Institute of Structural Mechanics, Bauhaus-Universität Weimar, Weimar, Germany.
    Rabczuk, Timon
    Institute of Structural Mechanics, Bauhaus-Universität Weimar, Weimar, Germany.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lu, Weizhuo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Multi-scale modeling in thermal conductivity of polyurethane incorporated with phase change materials using physics-informed neural networks2023In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 220, article id 119565Article in journal (Refereed)
    Abstract [en]

    Polyurethane (PU) possesses excellent thermal properties, making it an ideal material for thermal insulation. Incorporating Phase Change Materials (PCMs) capsules into Polyurethane has proven to be an effective strategy for enhancing building envelopes. This innovative design substantially enhances indoor thermal stability and minimizes fluctuations in indoor air temperature. To investigate the thermal conductivity of the Polyurethane-Phase Change Materials foam composite, we propose a hierarchical multi-scale model utilizing Physics-Informed Neural Networks (PINNs). This model allows accurate prediction and analysis of the material’s thermal conductivity at both the meso-scale and macro-scale. By leveraging the integration of physics-based knowledge and data-driven learning offered by Physics-Informed Neural Networks, we effectively tackle inverse problems and address complex multi-scale phenomena. Furthermore, the obtained thermal conductivity data facilitates the optimization of material design. To fully consider the occupants’ thermal comfort within a building envelope, we conduct a case study evaluating the performance of this optimized material in a detached house. Simultaneously, we predict the energy consumption associated with this scenario. All outcomes demonstrate the promising nature of this design, enabling passive building energy design and significantly improving occupants’ comfort. The successful development of this Physics-Informed Neural Networks-based multi-scale model holds immense potential for advancing our understanding of Polyurethane-Phase Change Material’s thermal properties. It can contribute to the design and optimization of materials for various practical applications, including thermal energy storage systems and insulation design in advanced building envelopes.

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  • 8.
    Liu, Xianghui
    et al.
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Chang, Qi
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Yan, Max
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Wang, Xin
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Zhang, Haiwen
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Zhou, Han
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Fan, Tongxiang
    State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
    Scalable spectrally selective mid-infrared meta-absorbers for advanced radiative thermal engineering2020In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 22, no 25, p. 13965-13974Article in journal (Refereed)
    Abstract [en]

    Metamaterials with spectrally selective absorptance operating in the mid-infrared range have attracted much interest in numerous applications. However, it remains a challenge to economically fabricate scalable meta-absorbers with tailorable absorptance bands. This work demonstrates a conceptually simple and low-cost yet effective design strategy to achieve spectrally selective absorption with tailorable band positions at MIR by colloidal lithography. The strategy ingeniously uses residual diameter fluctuations of circular resonators etched through monodisperse colloidal particles for achieving superposition of multiple magnetic resonances and thereby a more than doubled absorption band, which is neglected in previous works. The proposed meta-absorber features densely packed thick aluminum resonators with a rather narrow diameter distribution and enhanced capacitive coupling among them. Moreover, the tailorability of the absorption band can be achieved by a parameterized variation in the fabrication process. As a proof of concept, infrared stealth and radiative cooling are demonstrated based on our meta-absorbers. The design and fabrication strategy create versatile metamaterials for advanced radiative thermal engineering.

  • 9.
    Liu, Xianghui
    et al.
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Xiao, Chengyu
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Wang, Pan
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Yan, Max
    Department of Applied Physics School of Engineering Sciences KTH Royal Institute of Technology Stockholm 11419 Sweden.
    Wang, Huifen
    Shanghai Institute of Spacecraft Equipment Shanghai Academy of Spaceflight Technology Shanghai 200240 China.
    Xie, Peiwen
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Liu, Gang
    Shanghai Institute of Spacecraft Equipment Shanghai Academy of Spaceflight Technology Shanghai 200240 China.
    Zhou, Han
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Zhang, Di
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Fan, Tongxiang
    State Key Lab of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China.
    Biomimetic photonic multiform composite for high‐performance radiative cooling2021In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 9, no 22, article id 2101151Article in journal (Refereed)
    Abstract [en]

    Nanostructures on bodies of biological inhabitants in severe environments can exhibit excellent thermoregulation, which provide inspirations for artificial radiative cooling materials. However, achieving both large-scale manufacturing and flexible form-compatibility to various applications needs remains as a formidable challenge. Here a biomimetic strategy is adopted to design a thermal photonic composite inspired by the previously unexplored golden cicada's evolutionarily optimized thermoregulatory ability. A microimprint combined with phase separation method is developed for fabricating a biomimetic photonic material made of porous polymer–ceramic composite profiled in microhumps. The composite demonstrates high solar reflectance (97.6%) and infrared emissivity (95.5%) in atmospheric window, which results in a cooling power of 78 W m−2 and a maximum subambient temperature drop of 6.6 °C at noon. Moreover, the technique facilitates multiform manufacturing of the composites beyond films, as demonstrated by additive printing into general 3D structures. This work offers biomimetic approach for developing high-performance thermal regulation materials and devices.

  • 10.
    Marichelvam, M.K.
    et al.
    Department of Mechanical Engineering, Mepco Schlenk Engineering College, Tamilnadu, Sivakasi, India.
    Kumar, C. Labesh
    Department of Mechanical Engineering, Institute of Aeronautical Engineering, Telangana, Hyderabad, India.
    Kandakodeeswaran, K.
    Department of Mechanical Engineering, Mepco Schlenk Engineering College, Tamilnadu, Sivakasi, India.
    Thangagiri, B.
    Department of Chemistry, Mepco Schlenk Engineering College, Tamilnadu, Sivakasi, India.
    Saxena, Kuldeep K.
    Division of Research and Development, Lovely Professional University, Phagwara, India.
    Kishore, Kamal
    School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, NSW, Australia; Department of Civil Engineering, GLA University, Uttar Pradesh, Mathura, India.
    Kumar Wagri, Naresh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kumar, Sanjeev
    University of Virginia, United States.
    Investigation on mechanical properties of novel natural fiber-epoxy resin hybrid composites for engineering structural applications2023In: Case Studies in Construction Materials, E-ISSN 2214-5095, Vol. 19, article id e02356Article in journal (Refereed)
    Abstract [en]

    Polymers and fibers are the main components of cementitious composite materials to reinforce concrete. The synthetic fibers used in concrete composites typically weigh and also, and they are easily subjected to thermal degradation. To tackle the above issues, researchers developed various natural fiber-based composites. In the paper, the mechanical characteristics of hybrid composites were examined. The hybrid composites were developed using Madar, Gongura, and Hibiscus cannabinus fibers. The polyester resin was the matrix. The fibers were treated chemically using a 5% sodium hydroxide (NaOH) solution. The fibers were then carefully cleaned with distilled water twice and baked for 70 min at 60 °C. For the evaluation of the tensile, flexural, and impact properties of the hybrid composites, specimens were made in accordance with ASTM standards. The treated composite sample (S3) specimen exhibits a tensile strength (TS) of approximately 34.720 N/mm2, flexural strength (FS) of 77.957 MPa, and flexural modulus (FM) of 1548.588 GPa. The average water absorption of the sample is only 2.45%. The hardness and impact strength (IS) of the samples are also superior to those of several other composites studied in the literature. Hence, the proposed hybrid composites could be a potential material for reinforcing the concrete composites to provide a higher service rate and greater durability to the structures.

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  • 11.
    Medina, Lilian
    et al.
    Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, KTH Royal Institute of Technology, 10044 Stockholm, Sweden.
    Nishiyama, Yoshiharu
    Univ. Grenoble Alpes, CNRS, CERMAV, 38000 Grenoble, France.
    Daicho, Kazuho
    Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
    Saito, Tsuguyuki
    Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
    Yan, Max
    School of Engineering Sciences, KTH Royal Institute of Technology, 16440 Kista, Sweden.
    Berglund, Lars A.
    Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, KTH Royal Institute of Technology, 10044 Stockholm, Sweden.
    Nanostructure and properties of nacre-inspired clay/cellulose nanocomposites—synchrotron X-ray scattering analysis2019In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 52, no 8, p. 3131-3140Article in journal (Refereed)
    Abstract [en]

    Nacre-inspired clay nanocomposites have excellent mechanical properties, combined with optical transmittance, gas barrier properties, and fire retardancy, but the mechanical properties are still below predictions from composite micromechanics. The properties of montmorillonite clay/nanocellulose nanocomposite hybrids are investigated as a function of clay content and show a maximum Young's modulus as high as 28 GPa. Ultimate strength, however, decreases from 280 to 125 MPa between 0 and 80 wt % clay. Small-angle and wide-angle X-ray scattering data from synchrotron radiation are analyzed to suggest nanostructural and phase interaction factors responsible for these observations. Parameters discussed include effective platelet modulus, platelet out-of-plane orientation distribution, nanoporosity, and platelet agglomeration state.

  • 12.
    Xia, Yangyang
    et al.
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Zhang, Chao
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China; SAFEKEY Engineering Technology (Zhengzhou), Ltd, Zhengzhou, China.
    Wang, Cuixia
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Liu, Hongjin
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Sang, Xinxin
    Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Jiangsu Province, Wuxi, China; International Research Center for Photoresponsive Molecules and Materials, Jiangnan University, Jiangsu Province, Wuxi, China.
    Liu, Ren
    International Research Center for Photoresponsive Molecules and Materials, Jiangnan University, Jiangsu Province, Wuxi, China.
    Zhao, Peng
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China; SAFEKEY Engineering Technology (Zhengzhou), Ltd, Zhengzhou, China.
    An, Guanfeng
    Guangzhou Municipal Engineering Group Ltd., Guangzhou, China.
    Fang, Hongyuan
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Shi, Mingsheng
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Li, Bin
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Yuan, Yiming
    School of Water Conservancy and Transportation/Yellow River Laboratory/Underground Engineering Research Institute, Zhengzhou University, Zhengzhou, China; National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou, China; Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries, Zhengzhou, China.
    Liu, Bokai
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Prediction of bending strength of glass fiber reinforced methacrylate-based pipeline UV-CIPP rehabilitation materials based on machine learning2023In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 140, article id 105319Article in journal (Refereed)
    Abstract [en]

    Ultraviolet cured-in-place-pipe (UV-CIPP) materials are commonly used in trenchless pipeline rehabilitation. Their bending strength is a crucial indicator to evaluate the curing quality. Studies show that this indicator is affected by multiple factors, including the curing time, UV lamp curing power, curing distance, and material thickness. Laboratory experiments have limitations in analyzing the effect of multiple factors on the bending strength of UV-CIPP materials and quantitatively predicting the optimum curing parameters. Aiming at resolving these shortcomings, resolve machine learning techniques were applied to predict the bending strength. In this regard, the surface curing reaction temperature monitoring data and three-point bending data of 30 groups of UV-CIPP material under the influence of different curing parameters were used as a dataset to predict the bending strength of UV-CIPP material. The results show that the influence degree of each factor on the bending strength of the UV-CIPP material, from high to low, is as follows: UV lamp power (−0.439), the temperature at the illuminated side (−0.392), curing time (−0.323), the temperature at the back side (−0.233), curing distance (0.143) and material thickness (−0.140). The best penalty parameter c (44.435) and width g (0.072) of the kernel function in the support vector machine (SVM) model were obtained using the genetic algorithm (GA) optimization, and the results were compared with the grey wolf optimizer (GWO) and particle swarm optimization (PSO). The performed analyses revealed that the developed GA-SVM model exhibits the best prediction results compared to other machine learning algorithms. The optimum bending strength of the UV-CIPP material used in this test is 294.77 MPa, which corresponds to the curing time, UV lamp power, curing distance, material thickness, light side temperature, and back side temperature of 7.59 min, 157.33 mW/cm2, 189.99 mm, 4.38 mm, 79.49 °C, and 76.59 °C, respectively.

  • 13.
    Yan, M.
    et al.
    Optics and Photonics, School of Information and Communication Technology, KTH-Royal Institute of Technology, Electrum 229, Kista, Sweden.
    Dai, J.
    Optics and Photonics, School of Information and Communication Technology, KTH-Royal Institute of Technology, Electrum 229, Kista, Sweden.
    Qiu, M.
    Optics and Photonics, School of Information and Communication Technology, KTH-Royal Institute of Technology, Electrum 229, Kista, Sweden.
    Lithography-free broadband visible light absorber based on a mono-layer of gold nanoparticles2014In: Journal of Optics, ISSN 2040-8978, E-ISSN 2040-8986, Vol. 16, no 2, article id 025002Article in journal (Refereed)
    Abstract [en]

    We experimentally demonstrate a large area, optically opaque plasmonic absorber which can absorb 95% of visible light with an effective thickness of less than 150 nm. The absorber comprises, from top to bottom, a mono-layer of random gold nanoparticles, a dielectric spacer, and a bottom gold reflector. Reflectometry analyses show that its absorption is insensitive to the incidence's polarization or angle when the incident angle is less than 50°. At a larger incident angle, reflection increases and absorption spectra differ for two polarizations. Numerical simulations based on a 3D finite-element method suggest that the high absorbance is due to collective efforts of dipolar particle resonances, most often strongly coupled and forming chain resonances, as well as coupling of light to the surface plasmon polariton, irrespective of the incidence's polarization, through the top-layer particles. Similar high absorptivity is also demonstrated with silver or aluminum as the bottom reflector. These highly efficient visible light absorbers can be potential candidates for a range of passive and active photonic applications, including solar-energy harvesting as well as producing artificial colors on a large scale.

  • 14.
    Zhang, Haiwen
    et al.
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China.
    Ly, Kally C. S.
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China.
    Liu, Xianghui
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China.
    Chen, Zhihan
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China;;Walker Department of Mechanical Engineering, Materials Science & Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, USA.
    Yan, Max
    Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 16440 Kista, Sweden.
    Wu, Zilong
    Walker Department of Mechanical Engineering, Materials Science & Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, USA.
    Wang, Xin
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China.
    Zheng, Yuebing
    Walker Department of Mechanical Engineering, Materials Science & Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, USA.
    Zhou, Han
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China.
    Fan, Tongxiang
    State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240 Shanghai, China.
    Biologically inspired flexible photonic films for efficient passive radiative cooling2020In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 117, no 26, p. 14657-14666Article in journal (Refereed)
    Abstract [en]

    Temperature is a fundamental parameter for all forms of lives. Natural evolution has resulted in organisms which have excellent thermoregulation capabilities in extreme climates. Bioinspired materials that mimic biological solution for thermoregulation have proven promising for passive radiative cooling. However, scalable production of artificial photonic radiators with complex structures, outstanding properties, high throughput, and low cost is still challenging. Herein, we design and demonstrate biologically inspired photonic materials for passive radiative cooling, after discovery of longicorn beetles’ excellent thermoregulatory function with their dual-scale fluffs. The natural fluffs exhibit a finely structured triangular cross-section with two thermoregulatory effects which effectively reflects sunlight and emits thermal radiation, thereby decreasing the beetles’ body temperature. Inspired by the finding, a photonic film consisting of a micropyramid-arrayed polymer matrix with random ceramic particles is fabricated with high throughput. The film reflects ∼95% of solar irradiance and exhibits an infrared emissivity >0.96. The effective cooling power is found to be ∼90.8 W⋅m−2 and a temperature decrease of up to 5.1 °C is recorded under direct sunlight. Additionally, the film exhibits hydrophobicity, superior flexibility, and strong mechanical strength, which is promising for thermal management in various electronic devices and wearable products. Our work paves the way for designing and fabrication of high-performance thermal regulation materials.

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