Advanced Materials Research Vol. 983

Abstract: A novel cheap macromolecular intumescent flame retardant (IFR), was synthesized. Unsaturated polyester resin (UPR) was modified with IFR to get the flame retardant UPR, whose flammability and burning behavior were characterized by limiting oxygen index (LOI). 22.7% of weight of IFR was doped into UPR to get 28.5 of LOI. The thermal properties of epoxy resins containing IFR were investigated with thermogravimetry (TG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for UPR containing IFR, compared with UPR, IFR decreased weight loss, thermal stability, increased the char yield, which shows that IFR can catalyze decomposition and carbonization of UPR.

Abstract: Gold based bulk metallic glass was synthesized at with different quenching rates. Au₅₄Ag₅Pd₂Cu_24.3Si_14.7 alloy ingots were cast into wedge shape and cone shape samples. The critical casting thickness of this alloy composition was found to be 4 mm when cast in copper mold. Completely amorphous structure as found in sections thinner than 4 mm when considering a infinite copper plate geometry. In locations with slower cooling rates, there are small fractions of transformed nanocrystals. The transmission electron microscope (TEM) study of Au₅₄Ag₅Pd₂Cu_24.3Si_14.7 solidified microstructure could offer snap shots of nucleation and growth of crystals from nanometer to micrometer length-scale as evolved with different cooling rates. The phase evolution was recorded by transmission electron microscope study, electron diffraction and metallography using scanning electron microscope. The specimens comprised of both fully amorphous solid and nanocomposites which were the combination of nano-crystals of controlled sizes in amorphous matrix. Vickers hardness values increased to 350-450 Hv, when compared to sub 100-150 Hv level of conventional 18-k gold alloys as cast. The study offers a revolutionary way to create ultrahigh strength bulk metals that comprise of large percentage of nano-crystals in amorphous matrix.

Abstract: The contribution describes the experimental analysis for the improvement of the mechanical properties of samples of earth with the addition of Laponite nanoparticles. Were made two types of samples: the first consisting of soil, sand and water; the second consisting of soil, water, sand and Laponite nanoparticles. The operations performed were: chemical analysis of soil and sand; preparation of samples; Scanning Electron Microscope (SEM) observation of samples for the distribution of the elements, especially the Laponite nanoparticles; testing of compression strength and flexural strength of two types of samples; comparisons of the resulted of the mechanical tests. The improvement of the mechanical characteristics of the earth material using nanotechnology, will increase the use of eco-friendly, non-toxic, cost effective, available materials in architecture.

Abstract: In this paper, we consider the optimal reconfiguration planning problem of finding the least number of reconfiguration steps to transform between two configurations for chain-type modular robots. We propose an intelligent algorithm for solution of the problem. In particular, we use the set of parameterized k-covers problem and the approximate period problem to detect periodic regularities in genetic sequences of DNA nanomechanical robots. We try to use similar reconfiguration actions for similar parts of genetic sequences. We consider an artificial physics optimization algorithm. We use Runge Kutta neural networks for the prediction of virtual force law.

Abstract: nanonickel phosphide Ni₂P catalysts supported on TiO₂-Al₂O₃ support were prepared by impregnation. The catalysts were characterized by XRD, BET, and XPS. The effects of impregnation method,Ni₂P loading on catalyst structure and HDS activity were studied. The results indicated that co-impregnation method is beneficial to the formation of Ni₂P and can avoid the formation of Ni₁₂P₅. The catalyst prepared with co-impregnation method, Ni₂P loading of 30% exhibited the best performance. At a reaction temperature of 606 K, a pressure of 3.0 MPa, a hydrogen/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h^-1, the conversion of DBT HDS was 96.0%.

Abstract: In this paper, a novel stable piceatannol nanoemulsion is established. The piceatannol nanoemulsion formulation was screened based on the pseudo ternary phase diagrams. An optimized prescription was given as piceatannol 0.54%, EL-40 25.6%, ethanol 3.87%, castor oil 10.30%, water 60.23% (mass ratio), with the mean particle size 87.3 nm. The morphology of piceatannol nanoemulsion was characterized by TEM. The test results demonstrate that the nanoemulsion has dramatically improved the the solubility and release performance of piceatannol in ABS and PBS.

Abstract: Silver nanoparticles have been prepared using reductive polysaccharides (glucan) as protecting agents and silver nitrate as precursor via a facile green approach, and possible formation mechanism of silver nanoparticle was proposed in this paper. Silver nanoparticles appearance, size and size distribution were controlled by different synthesis technologies and reaction conditions. By changing the reaction conditions such as AgNO₃ solution concentration, glucan dosage, reaction temperature, reaction time, the parameters affecting the product shape, particle size and size distribution were investigated. The samples synthesized were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectrophotometer (UV-vis) methods. The results have showed that nanosilver particle with different shapes such as rod-like, sheet-like or flake and tree-like etc. can be prepared by reductive polysaccharides, and it is a green preparation technology.

Abstract: In this paper, a hybrid quasi-micro-pyramid structure is fabricated via nanosecond pulse laser micro-processing, which demonstrates a 15% drop in average reflectance as compared to the uniform quasi-micro-pyramid structures. The influences of laser fluence, pulse number, and designed pitch are also studied experimentally and systematically. The results show that reflection increases with the pattern pitch, decreases with pulse number, and a minimum in reflection is reached at a laser fluence of 4.83 J/cm2. The method here demonstrated provides an alternative and low-cost solution for broadband anti-reflection by hybrid structures with normal aspect ratio rather than uniform structures with high aspect ratio. Higher antireflection performance can be expected by optimizing the laser processing parameters.

Abstract: The material damages in aerospace industry caused by correction can be detected in many different products including welded and bolted areas in aircraft and jet engines. The corrosion occurs when different conducted materials contact to each other in electrolyte media and different conducted materials present potential difference that causes rusting. The rusting problems in products lead both safety issues and billions of dollar loss in different businesses including aerospace industry. This paper studies the rusting mechanism and anti-corrosive coatings by applying computational simulation and prototype experiment. Both computer-aided analysis and sample testing demonstrated similar results which confirm the feasibility of analytic methodology introduced in this research paper. Keywords: Nanotechnology, computer-aided analysis, nanocoating control, anti-corrosion, simulation modeling

Abstract: The melting mixing was applied in the preparation of Multiwalled carbon nanotubes/Polycarbonate (MWCNTs/PC) nanocomposites. MWCNTs/PC nanocomposites with different MWCNTs contents were prepared under different injection conditions. The mechanical property of nanocomposites was comparatively investigated. The results demonstrated that: the tensile property of the nanocomposites was slightly improved by MWCNTs content increasing; but as the MWCNTs contents went on to increase to 10wt%, the tensile strength and bending strength were obviously decreased about 35% and 47%, respectively, but the impact strength and hardness were increased. The center hardness of MWCNTs/PC nanocomposites was greater than the surface hardness. Besides, the changes on the mechanical properties of the nanocomposites were studies by changing the injection conditions. By Scanning Electron Microscopy (SEM) observation, the microstructure and morphology of nanocomposites were analyzed, revealing that the center of the nanocomposite distributed more MWNTs, and the injection conditions would affect the MWNTs’ dispersion in the matrix and the interfacial interaction between MWCNTs and PC.