Advanced Materials Research Vols. 560-561

Abstract: Crystallization of the basalt fibers can reduce their mechanical property. This paper is devoted to understand the crystallization behavior of basalt fiber and its control conditions. Basalt fibers were heated at 700, 750, 800, 900, 1000, 1050 °C for 2h, then cooled down to room temperature in air. The crystallization behavior of basalt fiber was investigated by means of differential thermal analysis (DTA), X-ray powder diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). The results indicate that diopside and anorthite phases appeared during crystallization process and the absorption bands of heat-treated samples in FTIR spectra split and become relatively sharp.

Abstract: Highly monodisperse and uniform-size vinyl functiona-lized silica spheres were synthesized directly from vinyltriethoxysilane (VTES) in water/ethanol mixed solution, and in this system, we successfully controlled the size and shape of hybrid silica spheres by adjusting the concentrations of the precursor VTES and catalyst ammonia. On the basis of the experiment results, it was found that hybrid spheres size significantly increased as the increment of concentration of VTES. However, increasing ammonia concentration resulted in decreasing of diameter of hybrid silica spheres from 542 to 272 nm. The morphologies and structure were determined by Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier transformed infrared (FT-IR).

Abstract: Abstract. To characterize the thermomechanical cyclic response, especially Pseudo-elastic behavior of NiTi shape-memory alloy (SMA) at different temperatures and different loading frequencies, a series of tests of both quasi-static and dynamic uniaxial compression cyclic loading have been performed on cylindrical samples, using an Instron servohydraulic testing machine and the Hopkinson technique. Transformation temperature, after dynamic loading is measured and compared with that of as-received state. The influence of the annealing temperature on the fatigue response is also examined. A few noteworthy conclusions are as follows: (1) Transformation temperature, can be changed under higher strain rates; (2) By changing the annealing temperature, the transformation stress and the dissipated energy of NiTi can also be obviously changed, so as it changes the transformation temperature, Af ;(3) In cyclic loading, the dissipated energy over cycles tends to be a minimum stable value, and it seems that cyclic loading leads to a stable Pseudo-elastic behavior of the alloy; (4) Repeated impact tests of the alloy produce slightly changes in the shape of the Pseudo-elastic loop and in the dissipated energy comparing with the quasi-static cyclic tests.

Abstract: The adsorption is a physico-chemical process in soil and aqueous environment. Precise determination of adsorption equilibrium isotherms of pollutants helps to understand their potential damages to environment. In this work, how solution pH and the Solid/Liquid (S/L) phase ratio affect the precision degree of results as to pollutants on adsorbents were investigated by calculating the relative deviation (R.D.) of the amount of adsorption (qe). Results show that the R.D. of qe might increases adversely with solution pH, and both pH and the concentrations of pollutants (Ce) should be carefully measured. The degree of the influence of the S/L phase ratio is greatly determined by the adsorption coefficient Kd.

Abstract: The MoO3/H-ZSM5 catalysts for CH4 dehydroaromatization are prepared by physically mixing MoO3 and HZSM-5 and calcining the mixtures under different atmospheres at different temperatures. Transmission infrared spectra have been used to characterize the acidic properties of the MoO3/HZSM-5 catalysts. On the base of observations obtained the effects of the calicination temperature and environment were discussed on the migration of Mo and its dispersion over HZSM-5.

Abstract: The solubility of caffeine in water between 323.15 and 353.15 K was measured using the balance method. The solubility trend was modeled by use of the modified Apelblat equation and Yaws equation. The calculated solubility values according to the two empirical equations compare favorably with the experimental data. Besides, the relationship between supersaturated ratio and induction time was studied with the method of laser, basing on which, the surface tension of caffeine at 283.15 K, 293.15 K and 298.15 K in water was calculated.

Abstract: Based on preliminary research results about Compton scattering of saline solution, a linear relationship between the scattered photon counts and the concentrations had been deduced for a certain solution and it had been found that the slope of the lines was decreasing with the atomic number of the cation increasing for LiC1, NaCl and KC1(the same result for MgC1BB2BB and BaC1BB2BB) solution. Now, in order to explain such rule of the slope, the microscopic mechanism of scatterers has been studied. Through the electronic structure of hydrated ions is analyzed in detail: the distance between hydration ion and O atom after optimized, the total energy of hydration ion, the equivalent charge distribution of hydration ion and the electronic density distribution of hydration ion. At last, it is concluded that the reason of the slope decreasing when the atomic number of the alkali cation for KC1, NaCl, LiCl solutions (or MgC1BB2BB and BaClBB2BB solutions) is the bounding strength of the system on its electrons become increasing, the probability of Compton scattering is decreasing, and it will constrain the increasing velocity of the scattered photon counts.

Abstract: The acrylic fibers were prepared by dry-jet wet spinning technology from polyacrylinitrile (PAN) /1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solution for the investigation of phase structure changing with drawing in boiling water. The DMA, WAXD and stress-strain measurements were conducted. It is shown that only a single Tg was observed from DMA and the paracrystalline structure was shown from WAXD. Although the the crystallinity and orientation increased with increasing draw ratio, the high crystallinity of the pre-drawn fiber indicates that the ordered structure was formed in the pre-drawn fiber by the high pre-drawn ratio (3.5) during the dry-jet wet spinning from high-viscosity PAN/[BMIM]Cl solution. It is also found that the initial modulus, ultimate elongation and tenacity increased with the increase of draw ratio.

Abstract: Effect of feed flow rate on velocity field of evaporating liquid film in a wiped film molecular distillatory was studied with a computational fluid dynamics (CFD) method. Three assumptions were introduced in order to simplify modeling processes. According to our previous study, the RNG k-εturbulent model treating near-wall flow was properly used in this simulation. The volume of fluid (VOF) multiphase model was also applied to track the liquid-gas surface. A near-wall modeling method, enhanced wall treatment, was used to consider the effect of walls. Simulations were carried out in rotating coordinate system. All simulation results are reasonably identical with real situation and were discussed in several aspects. It was concluded that increment of feed flow rate would reduce the turbulence of liquid film on the evaporator surface and then reduce the evaporation rate.