Reinforce concrete (RC) structures have been used to construct various types of offshore structures in the past decades. Reinforce concrete has many advantages such as high strength, relatively low cost, and easy main...
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The Norwegian Public Road Administration (NPRA) has initiated an ambitious project to replace the current ferry crossing solutions with floating bridges over the wide and deep Norwegian fjords. This will substantially...
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Development of an electrocatalyst that is cheap and has good properties to replace conventional noble metals is important for H_(2) *** this study,dealloying of an amorphous Ti_(37)Cu_(60)Ru_(3) alloy was performed to...
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Development of an electrocatalyst that is cheap and has good properties to replace conventional noble metals is important for H_(2) *** this study,dealloying of an amorphous Ti_(37)Cu_(60)Ru_(3) alloy was performed to prepare a freestanding nanostructured hydrogen evolution reaction(HER)*** effect of dealloying and addition of Ru to TiCu alloys on the microstructure and HER properties under alkaline conditions was investigated.3 at.%Ru addition in Ti_(40)Cu_(60) decreases the overpotential to reach a current density of 10mA cm^(-2) and Tafel slope of the dealloyed samples to 35 and 34mV dec−*** improvement of electrocatalytic properties was attributed to the formation of a nanostructure and the modification of the electronic structure of the ***-principles calculations based on density function theory indicate that Ru decreases the Gibbs free energy of water *** work presents a method to prepare an efficient electrocatalyst via dealloying of amorphous alloys.
Herein,ionomer-free amorphous iridium oxide(IrO_(x))thin electrodes are first developed as highly active anodes for proton exchange membrane electrolyzer cells(PEMECs)via low-cost,environmentally friendly,and easily s...
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Herein,ionomer-free amorphous iridium oxide(IrO_(x))thin electrodes are first developed as highly active anodes for proton exchange membrane electrolyzer cells(PEMECs)via low-cost,environmentally friendly,and easily scalable electrodeposition at room *** with a Nafion 117 membrane,the IrO_(x)-integrated electrode with an ultralow loading of 0.075 mg cm^(-2)delivers a high cell efficiency of about 90%,achieving more than 96%catalyst savings and 42-fold higher catalyst utilization compared to commercial catalyst-coated membrane(2 mg cm^(-2)).Additionally,the IrO_(x)electrode demonstrates superior performance,higher catalyst utilization and significantly simplified fabrication with easy scalability compared with the most previously reported ***,the remarkable performance could be mainly due to the amorphous phase property,sufficient Ir^(3+)content,and rich surface hydroxide groups in ***,due to the high activity,high cell efficiency,an economical,greatly simplified and easily scalable fabrication process,and ultrahigh material utilization,the IrO_(x)electrode shows great potential to be applied in industry and accelerates the commercialization of PEMECs and renewable energy evolution.
Direct numerical simulations (DNSs) are among the most powerful tools for studying turbulent flows. Even though the achievable Reynolds numbers are lower than those obtained through experimental means, DNS offers a cl...
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Direct numerical simulations (DNSs) are among the most powerful tools for studying turbulent flows. Even though the achievable Reynolds numbers are lower than those obtained through experimental means, DNS offers a clear advantage: The entire velocity field is known, allowing for the evaluation of any desired quantity. This capability includes the computation of derivatives of all relevant terms. One such derivative provides the indicator function, which is the product of the wall distance and the wall-normal derivative of the mean streamwise velocity. This derivative may depend on mesh spacing and distribution, but it is extremely affected by the convergence of the simulation. The indicator function is crucial for understanding inner and outer interactions in wall-bounded flows and describing the overlap region between them. We find a clear dependence of this indicator function on the mesh distributions we examine, raising questions about classical mesh and convergence requirements for DNS and achievable accuracy. Within the framework of the logarithmic plus linear overlap region, coupled with a parametric study of channel flows and some pipe flows, sensitivities of extracted overlap parameters are examined. This study reveals a path to establishing their high-Reτ or nearly asymptotic values at modest Reynolds numbers, but larger than the ones used in this work, accessible by high-quality DNS with reasonable cost.
Waste from low-density polyethylene products after lifespan accounts for 70% of solid waste in most dumpsites, contributing to environmental impacts. Eggshell foul smells are a threat to human and animal health. Befor...
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The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated tempera...
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The inverse relationship between the tribological and mechanical properties of environmentally friendly selflubricant films,induced by the addition of soft lubricant agents that can diffuse quickly at elevated temperatures,has hindered the widespread use of these materials in industrial *** paper took this challenge to break through the above established relationship by developing novel nacrelike multilayered Mo_(2)N–SiN_(x)/Ag–SiN_(x)self-lubricant films via an radio frequency(RF)magnetron sputtering system for real applications where harsh conditions at elevated temperatures *** multilayered films,deposited by alternating deposition of Mo_(2)N–SiN_(x)and Ag–SiN_(x)modulation layers,exhibited three phases of face-centered cubic(fcc)Mo_(2)N,fcc Ag and SiN_(x),where SiN_(x)encapsulated the nano-crystalline Mo_(2)N and Ag phases in each layer to successfully induce a“brick and mortar”nacre-like microstructure(in the area without the coherent structure).The epitaxy growth of the Ag–SiN_(x)layers with thickness below 6 nm on the Mo_(2)N template resulted in an extraordinary increase in both the hardness and elastic modulus,which was able to prevent severe degradation of the mechanical properties caused by the addition of *** room-temperature anti-friction property could be enhanced by increasing the Ag–SiN_(x)layer thickness due to the excellent lubricant nature of Ag,which acts in synergy with Mo_(2)N,while the wear rate below 4×10^(−8)mm^(3)/(N·mm)was due to the high mechanical *** tribological properties at 600℃also benefited from the interlocked multilayered architecture,which allowed an extreme low friction coefficient of~0.12 and a negligible wear rate(WR).This behavior was attributed to the synergism between the lubricant action of Ag and Mo_(2)N and the tribo-phase transformation from Ag_(2)Mo_(4)O_(13)to Ag_(2)MoO_(4).
The global goal of achieving 2000 gigawatts of offshore wind power by 2050 has driven the development of the wind energy sector. This ambitious goal is facing a significant challenge in maintaining the efficiency and ...
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The effect of hydrogen on the micromechanical characteristics of pure grade 2 titanium was investigated by comparing prenotched microcantilever bending in air versus in-situ electrochemical hydrogen charging. The nano...
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3D structures and electronic devices assembled through mechanically guided approaches have found important applications in a wide spectrum of emerging fields, including healthcare, biomedical engineering, wearable dev...
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