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Air entrainment 1

AuNPs 1

Block stability 1

CO and CO2 co-methanation 1

Connections 1

Dam safety 1

Fatigue 1

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Heavy metal ions 1

High-velocity jets 1

Mesoporous NiO 1

MgO 1

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Resin-injected bolts 1

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Catalytic combustion of methane over a highly active and stable NiO/CeO

Xiuhui Huang, Junfeng Li, Jun Wang, Zeqiu Li, Jiayin Xu

Frontiers of Chemical Science and Engineering 2020, Volume 14, Issue 4,   Pages 534-545 doi: 10.1007/s11705-019-1821-4

Abstract: In this paper, a NiO/CeO catalyst with high catalytic performance in methane combustion was synthesizedThe incorporation of NiO was found to enhance the concentration of oxygen vacancies, as well as the activityThe presence of CeO prevented the aggregation of NiO, enhanced reduction by NiO, and provided more oxygenkinetics study indicated that the reaction order was about 1.07 for CH and about 0.10 for O over the NiO

Keywords： methane combustion     NiO/CeO2 catalyst     interaction     oxygen vacancy     kinetic study    

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Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

Frontiers of Chemical Science and Engineering 2013, Volume 7, Issue 3,   Pages 289-296 doi: 10.1007/s11705-013-1345-2

Abstract: In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce Zr O (CZO) supportedThis is because the Ni surface was partially covered with MgO, and the strong interaction between NiOand NiMgO over CZO support led to the difficulty in reducing NiO to active Ni and thus less catalytic

Keywords： methane partial oxidation     NiO     ceria-zirconia     MgO     mixed oxide solid solution    

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Mechanical properties characterization of different types of masonry infill walls

André FURTADO, Hugo RODRIGUES, António ARÊDE, Humberto VARUM

Frontiers of Structural and Civil Engineering 2020, Volume 14, Issue 2,   Pages 411-434 doi: 10.1007/s11709-019-0602-y

Abstract: It is remarkable, the recent advances concerning the development of numerical modeling frameworks to simulate the infill panels’ seismic behavior. However, there is a lack of experimental data of their mechanical properties, which are of full importance to calibrate the numerical models. The primary objective of this paper is to present an extensive experimental campaign of mechanical characterization tests of infill masonry walls made with three different types of masonry units: lightweight vertical hollow concrete blocks and hollow clay bricks. Four different types of experimental tests were carried out, namely: compression strength tests, diagonal tensile strength tests, and flexural strength tests parallel and perpendicular to the horizontal bed joints. A total amount of 80 tests were carried out and are reported in the present paper. The second objective of this study was to compare the mechanical properties of as-built and existing infill walls. The results presented and discussed herein, will be in terms of strain-stress curves and damages observed within the tests. It was observed a fragile behavior in the panels made with hollow clay horizontal bricks, without propagation of cracks. The plaster increased the flexural strength by 57%.

Keywords： masonry infill walls     experimental characterization     compression strength     shear diagonal strength     flexural strength    

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An AuNPs/Mesoporous NiO/Nickel Foam Nanocomposite as a Miniaturized Electrode for Heavy Metal Detection Article

Boyuan Xue, Qian Yang, Kaidong Xia, Zhihong Li, George Y. Chen, Dayi Zhang, Xiaohong Zhou

Engineering 2023, Volume 27, Issue 8,   Pages 199-208 doi: 10.1016/j.eng.2022.06.005

Abstract: also propose a facile in situ hydrothermal calcination method to directly grow binder-free mesoporous NiOThe meticulous design of a low-barrier Ohmic contact between mesoporous NiO and AuNPs facilitates target-mediatednanochannel-confined electron transfer within mesoporous NiO.

Keywords： AuNPs     Mesoporous NiO     Miniaturized electrode     Heavy metal ions     Groundwater     Square wave voltammetry    

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Characterization and catalytic activity of soft-templated NiO-CeO

Luciano Atzori, Maria Giorgia Cutrufello, Daniela Meloni, Barbara Onida, Delia Gazzoli, Andrea Ardu, Roberto Monaci, Maria Franca Sini, Elisabetta Rombi

Frontiers of Chemical Science and Engineering 2021, Volume 15, Issue 2,   Pages 251-268 doi: 10.1007/s11705-020-1951-8

Abstract: Nanosized NiO, CeO and NiO-CeO mixed oxides with different Ni/Ce molar ratios were prepared by theNiO and CeO nanocrystals of about 4 nm in size were obtained, regardless of the Ni/Ce molar ratio.The Raman and X-ray photoelectron spectroscopy results proved the formation of defective sites at the NiO-CeO

Keywords： soft template method     NiO-CeO2 catalysts     CO and CO2 co-methanation     synthetic natural    

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An Enhanced Physically Based Scour Model for Considering Jet Air Entrainment

Rafael Duarte,António Pinheiro,Anton J. Schleiss

Engineering 2016, Volume 2, Issue 3,   Pages 294-301 doi: 10.1016/J.ENG.2016.03.003

Abstract:

Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets, this study presents adaptations of a physically based scour model. The modifications regarding jet aeration are implemented in the Comprehensive Scour Model (CSM), allowing it to reproduce the physical-mechanical processes involved in scour formation concerning the three phases; namely, water, rock, and air. The enhanced method considers the reduction of momentum of an aerated jet as well as the decrease of energy dissipation in the jet diffusive shear layer, both resulting from the entrainment of air bubbles. Block ejection from the rock mass depends on a combination of the aerated time-averaged pressure coefficient and the modified maximum dynamic impulsion coefficient, which was found to be a constant value of 0.2 for high-velocity jets in deep pools. The modified model is applied to the case of the observed scour hole at the Kariba Dam, with good agreement.

Keywords： Air entrainment     Uplift     Rock scour     Dam safety     High-velocity jets     Block stability     Scour assessment    

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A multi-integrated approach on toxicity effects of engineered TiO

DINIZ,Joana LOURENÇO,Isabel PERES,Luisa CASTRO,José Brito CORREIA,Joana PEREIRA,Isabel FERREIRA,António

Frontiers of Environmental Science & Engineering 2015, Volume 9, Issue 5,   Pages 793-803 doi: 10.1007/s11783-015-0775-0

Abstract: The new properties of engineered nanoparticles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applications, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation of nanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO nanoparticles (Aeroxide® P25), two phase composition of anatase (65%) and rutile (35%) with an average particle size value of 27.6±11 nm were used. Results on the EC for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant showed no effect on growth. The fish showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease ( <0.05) after 14 days of exposure for all tested concentrations. The presence of TiO nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.

Keywords： ecotoxicity     enzymatic analysis     histology     transmission electron microscopy (TEM)     TiO2-nanoparticles    

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A novel color image encryption algorithm based on a fractional-order discrete chaotic neural network and DNA sequence operations Research Articles

Li-ping Chen, Hao Yin, Li-guo Yuan, António M. Lopes, J. A.

Frontiers of Information Technology & Electronic Engineering 2020, Volume 21, Issue 6,   Pages 809-962 doi: 10.1631/FITEE.1900709

Abstract: A novel algorithm based on dynamic deoxyribonucleic acid (DNA) encoding and chaos is presented. A three-neuron fractional-order discrete Hopfield neural network (FODHNN) is employed as a pseudo-random chaotic sequence generator. Its initial value is obtained with the secret key generated by a five-parameter external key and a hash code of the plain image. The external key includes both the FODHNN discrete step size and order. The hash is computed with the SHA-2 function. This ensures a large secret key space and improves the algorithm sensitivity to the plain image. Furthermore, a new three-dimensional projection confusion method is proposed to scramble the pixels among red, green, and blue color components. DNA encoding and diffusion are used to diffuse the image information. Pseudo-random sequences generated by FODHNN are employed to determine the encoding rules for each pixel and to ensure the diversity of the encoding methods. Finally, confusion II and XOR are used to ensure the security of the encryption. Experimental results and the security analysis show that the proposed algorithm has better performance than those reported in the literature and can resist typical attacks.

Keywords： 分数阶离散系统；神经网络；DNA加密；彩色图像加密    

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Fatigue Strength Evaluation of Resin-Injected Bolted Connections Using Statistical Analysis

José António Fonseca de Oliveira Correia, Bruno Alexandre Silva Pedrosa, Patrícia

Engineering 2017, Volume 3, Issue 6,   Pages 795-805 doi: 10.1016/j.eng.2017.12.001

Abstract:

Different strategies can be used to perform reparations and reinforcements of ancient bolted and riveted metallic bridges. As the riveting process is not currently a common practice, it requires proper equipment and skilled workers. Another solution is the use of welding. However, the weldability of old steels is poor. Bolts are very attractive alternative solutions, and are most commonly used to repair old metallic bridges. Fitted bolts are expensive solutions; the alternative is the use of resin-injected bolts. The behavior of bolted joints with preloaded resin-injected bolts has been studied using quasi-static and creep tests; however, few studies on the slip and fatigue behavior of these joints can be found in the literature. This paper presents an overview of a few experimental programs that were carried out by several authors aiming at evaluating the fatigue behavior of single and double shear resin-injected bolted connections. A comparison between the experimental data of joints with preloaded standard bolts and preloaded resininjected bolts shows a fatigue strength reduction in the latter. Since Eurocode 3 (EC3) suggests the same fatigue strength curve for joints made of resin-injected bolts and standard bolts, this may raise some concerns. Furthermore, research on the feasibility of using both bonded and bolted connections is shown. This last study was performed with high-strength low-alloy structural steel plates and an acrylic structural adhesive for metal bonding. For both case studies, a statistical analysis is performed on fatigue experimental data using linearized boundaries and the Castillo and Fernández-Canteli model. Fatigue design curves are proposed and compared with the design suggestions of several European and North American standards.

Keywords： Fatigue     Connections     Structural reinforcements     Structural adhesives     S-N curves     Resin-injected bolts    

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Title Author Date Type Operation

Catalytic combustion of methane over a highly active and stable NiO/CeO

Xiuhui Huang, Junfeng Li, Jun Wang, Zeqiu Li, Jiayin Xu

Journal Article

Methane partial oxidation over NiO-MgO/Ce

Piyawat PUE-ON, Vissanu MEEYOO, Thirasak RIRKSOMBOOON

Journal Article

Mechanical properties characterization of different types of masonry infill walls

André FURTADO, Hugo RODRIGUES, António ARÊDE, Humberto VARUM

Journal Article

An AuNPs/Mesoporous NiO/Nickel Foam Nanocomposite as a Miniaturized Electrode for Heavy Metal Detection

Boyuan Xue, Qian Yang, Kaidong Xia, Zhihong Li, George Y. Chen, Dayi Zhang, Xiaohong Zhou

Journal Article

Characterization and catalytic activity of soft-templated NiO-CeO

Luciano Atzori, Maria Giorgia Cutrufello, Daniela Meloni, Barbara Onida, Delia Gazzoli, Andrea Ardu, Roberto Monaci, Maria Franca Sini, Elisabetta Rombi

Journal Article

An Enhanced Physically Based Scour Model for Considering Jet Air Entrainment

Rafael Duarte,António Pinheiro,Anton J. Schleiss

Journal Article

A multi-integrated approach on toxicity effects of engineered TiO

DINIZ,Joana LOURENÇO,Isabel PERES,Luisa CASTRO,José Brito CORREIA,Joana PEREIRA,Isabel FERREIRA,António

Journal Article

A novel color image encryption algorithm based on a fractional-order discrete chaotic neural network and DNA sequence operations

Li-ping Chen, Hao Yin, Li-guo Yuan, António M. Lopes, J. A.

Journal Article

Fatigue Strength Evaluation of Resin-Injected Bolted Connections Using Statistical Analysis

José António Fonseca de Oliveira Correia, Bruno Alexandre Silva Pedrosa, Patrícia

Journal Article