With selfmade porous micromodel,the experiments of emulsion flow in a porous medias were conducted.The results indicate that the flow characteristics of emulsion in porous media are very complex,and the emulsion is plugged in the pour throats obviously.There are three main mechanisms of drop capture.The characteristics of emulsion rheology appears sheared pseudoplastic of nonNewton fluid as emulsion flows at the higher velocity in porous micromodels,which is similar with its in viscometers before it enters the porous micromodels.The results of the study may provide a theoretical guidance for designing water blockoff,ASP flood and displacement with emulsion.
Microstructure, hydrogen storage properties and thermal stabilities of V-Ti-Fe alloys prepared by arc-melting were studied in this work. It was confirmed that V 60 Ti 3 0 Fe 10 , V 70 Ti 2 0 Fe 10 and V 80 Ti 1 0 Fe 10 alloys are a body-centered cubic (bcc) single phase, while V 75 Ti 1 0 Fe 15 alloy consists of the bcc main phase and C14-typed Laves secondary phase. Experimental results show that the V 80 Ti 1 0 Fe 10 alloy reached the largest hydrogen absorption capacities which were about 1.9 wt.% and 1.62 wt.% at 423 K and 473 K, while V 75 Ti 1 0 Fe 15 alloy with C14-typed Laves phase showed better hydrogen desorption capacities with 1.31 wt.% at 423 K and 1.35 wt.% at 473 K, respectively. In addition, the DSC measurements indicate that the thermal stability of V 75 Ti 1 0 Fe 15 alloy with C14-typed Laves phase decreased, which is very beneficial to the improvement of dehydrogenation rate in the alloy.
Hydroxyapatite/Chitosan bioceramics were fabricated by combining in-situ chemical synthesis and freeze drying method, using (NH4)2HPO4, Ca(NO3)2·4H2O, and chitosan(CS) as raw materials. The effect of solid loading and freeze-drying time on microstructures of hydroxyapatite/Chitosan bioceramics was studied. The microstructures of the fabricated porous bioceramics were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the hydroxyapatite/Chitosan bioceramics have interconnected porous structures from several microns to 200um, more suitable to bone tissue implantation. In addition, the porous structures are affected solid loading of slurry and freeze-drying time.
In the present study, billet is designed by utilizing the flow relief-hole principle to improve the dimensional accuracy during the cold precision forging of helical gear.A three-dimensional FE simulation was carried out to analyze the deformation features of billet with different initial diameter of relief-hole under the commercial software DEFORM 3D.When the diameter of relief-hole d0 increases, the forming load decreases and the unfilled portions at the teeth top contacting with the punch increase.The deform mode of relief-hole, the variation trend and the distribution of effective strain are different under different diameter of relief-hole when compression ratio Δs varies.
Here, successful fabrication of zirconia/carbon network composite by gelcast and reduction sintering in argon gas is reported. Carbon network well distributed on the grains and the boundaries is confirmed by FE-SEM, TG–DTA, XRD, and, degree of graphitization by Raman spectroscopy. Electrical resistivity of 16.1 Ω-cm indicates that thus formed carbon network in the zirconia matrix is expected to improve the electrical conductivity of the composite system.
The fundamental mechanism behind oil/water separation materials is their surface wettability that allows either oil or water to pass through. The conventional materials for oil/water separation generally have extreme wettability, namely superhydrophilic for water separation and superhydrophobic for oil separation. Using easily accessible materials that are medium hydrophobic or even relatively hydrophilic for preparing highly efficient oil/water separators have rarely been reported. In this work, a new strategy by triggering phase transition of infused lubricant from liquid to solid state in porous structure is realized in fabricating slippery lubricant infused porous structure for oil/water separations. By infusing polyester fabric with coconut oil, after phase transition, excellent water repellency and oil permeability by an absorbing-permeating mechanism are achieved, despite the low water contact angle on the new material. Although the new phase transformable slippery lubricant infused porous structure, features much milder hydrophobicity than conventional oil/water separators, it can remove diverse types of oil from water with high efficiencies. The phase transformable slippery lubricant infused porous structure is able to maintain their water repellency after immersing in high concentration salt (10 wt% NaCl), acid (25 % HCl), alkaline (25 % NH3·H2O) solutions for 120 h, showing remarkably functional durability in harsh environment. The lubricant phase transition mechanism proposed in this study is universally applicable to porous substrates with various chemical compositions and pore structures, such as porous sponges or even daily life breads, for creating efficient oil/water separators, which can serve as a novel accessible design principle of phase transformable slippery lubricant infused porous structure for eco-friendly oil/water separators.
Fracture behavior of interface of composite materials was studied by photoelastic method. Crack growth along the interface was observed clearly, stress distribution and the debonding stress were calculated according to the photoelastic pattern.
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