Abstract: (Bi2O3Fe2O3)0.8(Nb2O5)0.2 was synthesized by solid state reaction method. (Bi2O3Fe2O3)0.8(Nb2O5)0.2 was made for the investigation of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Dielectric property. XRD pattern reveals that three phases were obtained with Bismuth Iron Niobium Oxide. SEM elicits that grain size increases with the enhancement of sintering temperature. Dielectric property decreases with the augmentation of frequency.
Abstract: In 1985, H.A. Janssen studied the structure of the forces inside a silo filled with granular materials, so-called Janssen’s Effect Method (J.E.M). This method is a unique property of confined granular materials. The pressure at the bottom saturated with an increasing filling height due to internal friction with side walls. In this research, we focus on the study of granular cohesionless materials such as sands and gravels, these forces are explained by adsorption and capillary phenomenon. Our main result shows that positive water pressures generate a mechanical effect with tendencies of removing the components of the porous medium corresponding to the mechanical buoyancy force (FB) that increases with increasing θ from calculated by Janssen's effect method. The topic in this research is once importance in study physical processes of the problem in the Geology Physics (i.e. the factor causing landslide).
Abstract: In the paper a new permeability model based on matchstick model accounting for stress change and matrix shrinkage and swelling caused by gas mixture (CH4 and CO2) is proposed. Finally, a history matching exercise is carried out using field data and experimental data and several models are compared to determine the accuracy of the new model. The modeling results show that the new model can fit the experimental results well. With the exchange of CH4 on coal matrix with CO2, the coal matrix tends to swell and the coal permeability will decrease. So the fracture pressure has better to be high enough to guarantee the easy flow of gases in coal seam. Only when we know the coal permeability change during CO2 injection, can we have better knowledge about the ECBM performance and CO2 sequestration feasibility for a certain coal seam.
Abstract: Well-grown M3MgSi2O8 (M = Ca, Sr and Ba):Eu2+ phosphors were synthesized by novel melt quenching synthesis method. The luminescence property of the Sr3MgSi2O8:Eu2+ phosphor synthesized by the melt synthesis method is comparable to those of the sample synthesized by a conventional solid state reaction. Sintered phosphor balls with excellent luminescent characteristics were obtained.
Abstract: In this research, zinc oxide (ZnO) films were prepared by thermal evaporation method at temperature between 400-600°C for 60 min. Then, ZnO films were deposited by nitrogen cold plasma technique. The power, frequency and voltage of plasma generated at 100 W, 50 KHz and 5 KV, respectively. These films were deposited by plasma deposition for 15-60 min. The aim of this research is to study the effect of nitrogen plasma on the crystalline structure and optical properties of ZnO film. Crystalline structure, elemental compositions, morphological and optical properties were characterized by using X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDS), scanning electron microscopy (SEM) and UV-VIS spectrophotometer, respectively. It was found that the ZnO films preparation via thermal evaporation method at temperature of 500°C showed the highest crystalline with hexagonal structure. After plasma deposition for 15, 30 and 60 min, ZnO films were amorphous. Optical transmittance values decreased and the optical band gap decreased from 3.14 to 3.06 eV with increasing in the plasma time.
Abstract: The aims of present study were investigated the effect of nickel doping on the dielectric and piezoelectric properties of P(BN)ZT solid solution. P(BN)ZT powder doped with nickel nanoparticle in the composition of (1-x) PBNZT–xNi when x = 0, 2, 4, 6, 8 and 10 percent by mole. P(BN)ZT doped with nickel powder were calcined at 900 °C for 2 h and sintered at the temperature range of 1150 -1250°C for 2 h with heating/cooling rate of 5 °C/min. The dielectric constant (er) and the dielectric loss tangent (tand) of all ceramics were measured at room temperature using LCR meter. The piezoelectric properties (d33) were measured at room temperature using d33 meter. The micro and nano-domain structure was clearly observed by piezo-response force microscopy (PFM). From the results, it can be seen that the dielectric and piezoelectric decreased with increasing Ni particle of all composition (0.0-0.1 mol%). Moreover, PFM images show that the micro (180°) and nano (90°) domain are orientated at the surface region in submicron-scale of P(BN)ZT ceramics with doped nickel nanoparticle.
Abstract: Fatigue failures occur due to the application of fluctuating stresses that are much lower than the stress required to cause failure during a single application of stress. The process is dangerous because a single application of the load would not produce any ill effects, and a conventional stress analysis might lead to assumption of safety that does not exist. The fatigue process is thought to begin at an internal or surface flaw here the stresses are concentrated, and consists initially of shear flow along slip planes. The mechanisms of fatigue-crack propagation are examined with particular emphasis on the similarities and differences between cyclic crack growth in ductile materials, such as metals, and corresponding behavior in brittle materials, such as intermetallic and ceramics. Fatigue, as understood by materials technologists, is a process in which damage accumulates due to the repetitive application of leads that may be well below the yield point.
Abstract: The laboratory-scale study was conducted to assess the feasibility of using dredged sediments with waste glasses to produce facing bricks. This study was investigated into three different proportions of waste glasses ranging from 0, 20, and 40% by weight mixed with dredged sediments as raw materials in producing facing bricks. The characteristics of the dredged sediments, waste glasses, and fired facing bricks were analyzed using X-ray fluorescence (XRF) and X-ray diffraction (XRD. The physical-mechanical properties of fired bricks were compliant with the criteria for facing bricks (Thai Industrial Standards 168-2546). The results showed that major chemical compositions of dredged sediments and waste glasses were silica (SiO2) with the value of 43.50% and 70.70%, respectively. Heavy metal contents including Cr, Cu, Zn, As, Cd, Hg, Pb, Mn, Sr, and Ni were lower than the soil quality standard. Results of this study indicated that dredged sediments and waste glasses are suitable as primary raw materials in the production of facing bricks and could be considered to represent an environmental friendly product.
Abstract: Polymers rank among a significant group of technical materials. One of requirements for this constructional material is to have enough resistance to a dynamic loading. Especially in the area of connecting the materials reactoplastics are used, which are distinguished for a low resistance to the dynamic loading. One solution for increasing an impact strength is filling the reactoplastics, i.e. a formation of polymer composites. The aim of the research was to evaluate an impact strength of various polymer materials (composites filled with different types of a filler, structural two-component epoxies, mixed recycled plastics, PPO – polyphenyle oxide and PS – polystyrene). The Dynstat method CSN 64 0611 was chosen for the evaluation of the impact strength. Reactoplastics matrix on the basis of two-component epoxy adhesive with high liquidity and an increased speed of a hardening GER reaches low values of the impact strength (2.54 ± 0.30 kJ·m-2). It is evident from the experimental results the positive effect of aluminium microparticles GER MFAI (3.26 ± 0.35 kJ·m-2), glass beads GR B134 (2.83 ± 0.29 kJ·m-2) and microfibres of polyamide from the process of tyre recovery GER MPA (3.92 ± 0.25 kJ·m-2) on the impact strength. The results of this experiments show the possibility of the modification of the relative fragile epoxy resin with the filler, which increases the impact strength.