Protocol for preparation of highly durable superhydrophobic bulks with hierarchical porous structures

Superhydrophobic surfaces face challenges in comprehensive durability when used in extreme outdoor environments. Here, we present a protocol for preparing nanocomposite bulks with hierarchical structures using the template technique. We describe steps for using hybrid nanoparticles of polytetrafluoroethylene and multi-walled carbon nanotube to fill inside and dip on the polyurethane (PU) foam. We then detail procedures for its removal by sintering treatment. The extra accretion layer on the PU foam surface was highlighted to construct hierarchical porous structures. For complete details on the use and execution of this protocol, please refer to Wu et al.

Porous bulk superhydrophobic nanocomposites for extreme environments

Robust superhydrophobic materials providing protections from harsh weather events such as hurricanes, high temperatures, and humid/frigid conditions have proven challenging to achieve. Here, we report a porous bulk nanocomposite comprising carbon nanotube (CNT)-reinforced polytetrafluoroethylene (PTFE). The nanocomposites are prepared using a templated approach by infusing a CNT/PTFE dispersion into a sponge followed by thermal annealing and decomposition of the sponge template. Importantly, an excess accretion of CNT/PFFE particle mixture on the sponge resulted in nanocomposites with unique and hierarchical porous microstructure, featuring nanochannels near the surface connected to microscale pores inside. The superhydrophobic nanocomposite could resist liquid jets impacting at a velocity of �85.4 m s1 (Weber number of �202,588) and exhibits excellent high-temperature resistance as well as mechanochemical robustness. The porous nanocomposites display excellent icephobicity both with and without infusion with polydimethylsiloxane/silicone oil. These properties should facilitate exploitation as stiff/strong structural polymeric foams used in a variety of fields

Artificial intelligence : A powerful paradigm for scientific research

Y Artificial intelligence (AI) coupled with promising machine learning (ML) techniques well known from computer science is broadly affecting many aspects of various fields including science and technology, industry, and even our day-to-day life. The ML techniques have been developed to analyze high-throughput data with a view to obtaining useful insights, categorizing, predicting, and making evidence-based decisions in novel ways, which will promote the growth of novel applications and fuel the sustainable booming of AI. This paper undertakes a comprehensive survey on the development and application of AI in different aspects of fundamental sciences, including information science, mathematics, medical science, materials science, geoscience, life science, physics, and chemistry. The challenges that each discipline of science meets, and the potentials of AI techniques to handle these challenges, are discussed in detail. Moreover, we shed light on new research trends entailing the integration of AI into each scientific discipline. The aim of this paper is to provide a broad research guideline on fundamental sciences with potential infusion of AI, to help motivate researchers to deeply understand the state-of-the-art applications of AI-based fundamental sciences, and thereby to help promote the continuous development of these fundamental sciences.Peer reviewe

Effect of molecular structure of polyurethane elastomer on damping and mechanical properties

In order to obtain polyurethane elastomer (PUE) for reducing the vibration and noisy in deep-water environments, toluene diisocyanate (TDI), polypropylene glycol 2000 (PPG2000) and triethanolamine (TEA) were selected as raw materials, and the effects of hard segment content, R value and synthesis route on damping property and compression modulus of PUE were explored. Results reveal that the tanδ of PUE could be decreased with the increase of hard segment content, while the compression modulus increases. With the increase of R value, Tg increases, the compression modulus first increases and then decreases, reaching a peak when R=2. The prepolymer process and one-step process have little effect on the tanδ, but the compression modulus of PUE synthesized by prepolymer process is obviously greater than that of one-step process, which is more in line with the requirements of high damping/strong pressure resistance. It was observed that the compression modulus of PUE can be effectively improved by increasing the stiffness of molecular chain, the degree of hydrogen bonding and the uniformity of hard segment micro region distribution, but for damping property have a negative impact

Research progress in manufacturing technology of aviation composite propeller blade

Propeller propulsion technology plays an important role in aviation field. Composite materials have the characteristics of high specific strength，high specific modulus，high damping，designability and so on. The use of composite material propeller blades can further improve the performance of propeller in terms of mass reduction efficiency，propulsion efficiency，corrosion resistance，noise reduction. Composite material propeller blades have become the general trend. Based on aircraft propeller blades and rotor blades，this paper aims to perform a brief review of the research achievements of aviation composite propeller blades at home and abroad，classifies and expounds the material systems，structural design and molding processes of aviation propellers. The key technical problems and the simulation research on manufacturing process of propeller at home and abroad are summarized. Finally，the future development direction of domestic composite propellers from the aspects of improving the material system，optimizing the structure design，deepening the process research and strengthening the engineering application of numerical simulation technology are concluded

Performance Analysis of Thiocarbonohydrazide as a Novel Selective Depressant for Chalcopyrite in Molybdenite-Chalcopyrite Separation

A novel surfactant, thiocarbonohydrazide (TCH), was synthesized and tested for the first time as a selective chalcopyrite depressant in Cu-Mo separation. Its adsorption mechanisms on chalcopyrite were studied by flotation tests, zeta potential, FTIR, XPS and ToF-SIMS measurements. FTIR and zeta potential analyses suggested that there was a strong chemisorption reaction between TCH and chalcopyrite, resulting in the formation of TCH–copper complexes. XPS and ToF-SIMS measurements further confirmed the chemisorption of TCH onto the chalcopyrite surface and showed that this chemisorption reaction is due to its S and N atoms, which form five-membered chelating rings by releasing H ions

Removal and utilization of calcite existed in scheelite by preparation of calcium sulfate whiskers

In order to eliminate the effect of calcite associated with scheelite on the scheelite flotation, hydrochloric acid was used to dissolve the calcite, and the soaking solution was used to prepare CaSO4 whiskers by hydrothermal reaction with sulfuric acid at ambient pressure. First, the condition experiments of preparing CaSO4 whiskers by using CaCl2 and H2SO4 were carried out to optimize reaction parameters of the crystallization process. The optimal conditions were: at 102 °C reaction temperature, 0.5 mol/L reactant concentration and 60 min reaction time. Then based on the condition experiments and considering keeping acid concentration stable for achieving HCl recycling, Calcium sulfate whiskers with the average diameter of 1.41 μm and the average aspect ratio of 109 were prepared by the soaking solution after evaporating to half of its volume and 1.0 mol/L H2SO4 at 102 °C for 60 min. After ion exchange processing, the filtrate could be used as HCl in the process of HCl dissolution. Keywords: Calcium sulfate whiskers, Scheelite, Calcite, HCl, Hydrothermal reactio

Modulated reflectivity via a symmetrical metal cladding ferrofluids core waveguide chip

We report results of experiments and calculations that help to clarify the underlying physics of the light matter interaction in a symmetrical metal cladding ferrofluids core waveguide chip. Without applying external magnetic field, the observed tunable reflectivity confirms the formation of regular particle aggregates in the ferrofluids under the excited ultrahigh-order modes. A tentative explanation is proposed based on the competition between the optical trapping effect and the Soret effect as the field intensity increases