Papers by Keyword: Particle Size

Abstract: The effect of particle size of natural graphite on the size and structure of graphene oxide (GO) was investigated by using natural flake graphite (NFG) with different particle size. GO was prepared by modified Hummers method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, laser scattering particle size distribution analyzer and Atom force microscopy (AFM) were used to identify the characteristics of NFG and GO. The results provide evidence of how the graphite particle size affects the oxidation process and sheet size of the GO. Varies size monolayer GO sheets could be produced from the graphite with different particle size. The sheet size of GO is much smaller than that of the graphite, and the sheet size reduced multiple is proportional to the graphite particle size. The smaller particle size graphite is easily to be oxidized for a higher concentration GO suspension, and for more defect in the structure. Thus, this study leads to a better understanding of the preparation process of GO and provides a way to produce GO in different sheet size suitable for different applications.

Abstract: Due to the particularity of its percolation of low permeability reservoirs, water injection is very difficult and damage to the reservoir, especially the impurities in injection Wells, at the same time affect the injection efficiency, it will ultimately affect the recovery of the reservoir and the oilfield production. So it is necessary to carry out the ingredients and the causes of impurities in injection wells, clearing the Source for different kinds of impurity to provide the basis for reduce the impurity content in injection wells. In this paper, the author analyzed impurities particle size, composition and content in oilfield injection water In Longhop Oilfield through the indoor experiment, and with the comparison between the ion content and composition of the filtered water samples, analyzing the cause of the impurity within the wellbore. Experimental results show that in oil field water injection well, impurities particle size are mainly distributed between 2.6 and 5.4 um, impurity content mainly changes between 0.003746% and 0.017189%, the main ingredients of impurities is Fe₂O₃ and acid insoluble substances (SiO₂). Fe₂O₃ mainly comes from the injection water; acid insoluble substances mainly come from the formation sand production.

Abstract: Several micrmeter-size Cu powders were synthesized by a simple and green wet-chemical process. Moreover, changes in particle size are examined with different synthesis temperatures and amounts of gelatin reducing agent. All powder samples synthesized in this study were indexed as a Cu phase despite the synthesis was performed in air. The particle size decreased with increasing the gelatin content in principle, indicating that gelatin is an effective agent in suppressing aggregation between synthesized particles. The smallest average particle size was 1.53 μm.

Abstract: The p-aminobenzensulfonate-phenol-formaldehyde (APF) condensate is synthesized and characterized by FTIR and TGA analyses. Its properties as drilling mud fluid loss reducer are studied with respect to fluid loss and particle size distribution. In addition, the effect of salt on properties of APF condensate was discussed. Test results show that the APF condensate not only possesses higher thermal stability than sulfomethylated phenolic resin (SMP), a commercial drilling mud additive, but also achieves good property of fluid loss control by reducing the permeability of filter cake; the fluid-loss controlling properties of APF condensate dropped with the increase of concentrations of NaCl.

Abstract: High performance nanostructured light metals and alloys are very interesting for replacing conventional heavier materials in many industrial components. High Energy Ball Milling and Cryomilling are useful techniques to obtain nanocrystalline powders. In this work the effect of several milling conditions such as rotation speed, time, ball to powder ratio and temperature on the crystallite and particle size and morphology in pure aluminum are presented. X-Ray Diffraction, Laser Diffraction and Scanning Electron Microscopy are used. High energy ball milling at ambient and cryogenic temperature of Al powders rapidly leads to a nanometer size down to about 35 nm. High ball to powder ratio promotes both low crystallite and particle size. Small crystallite size like 18 nm and particle size as 4 μm were achieved in the most energetic conditions at ambient temperature. Isopropyl alcohol used as liquid media and protective atmosphere has a strong influence on the results depending on the milling temperature of Al.

Abstract: Due to high reaction activity and high combustion heat release, magnesium is widely used in the field of explosives. The research focus of this article is the effect of magnesium powder size and content on the thermal decomposition of PTFE. Two different particle sizes of magnesium powder are regarded as research objects. The thermal behavior of Mg/PTFE energetic system was investigated by TG-DSC analyzer. The experimental results show that magnesium has a catalytic effect on the thermal decomposition of PTFE. With the increase of magnesium content , the decomposition peak temperature of PTFE decreased firstly and when passed the ratio 50% increased, the best mixing ratio is Mg: PTFE =50:50. Within nanopowder, the activation energy of PTFE decreased by 150kJ∙mol^-1 compared to 112 kJ∙mol^-1 by mixing with micro powder. Obviously nanopowder has a better reactivity than micro powder, so has a more obvious catalytic effect.

Abstract: In this paper, the correlation between the particle size and rheological properties of MRE was discussed through both experimental results and theoretical analysis. It shows that the particle size can significantly influence the magnetorheological effect by changing the initial shear modulus and the saturated magnetic-induced shear modulus . With an increase in the particle size, the initial shear modulus gets lower, and the saturated magnetic-induced shear modulus increases to the maximum and then decreases. The larger the particle size is, the longer the distance between neighbor particles along the magnetic field is. Based on the relationship between the particle size and shear modulus, there exists an optimum size for added particles. Moreover, the performance of MRE can be improved by optimizing the particle size based on those rules.

Abstract: Based on side lateral scattering technique, a particle analysis apparatus for clinical liquid sample provided a precise and accurate method to acknowledge and transversely compare the particle properties at the micro-level. To improve the detection capability and lessen the lower detection limit of particle size, a photoelectric detection circuit including two parts of pre-amplifier and noise reduction was designed in accordance with the properties of lateral scattering signals. The circuit has the characteristics of working stable at high frequency band, high SNR and wide dynamic input range. Experiments show that the apparatus with the circuit mentioned can detect 0.3μm particle effectively and has broad application prospects in differential blood count, injection quality control and many other areas.

Abstract: The present study was undertaken to study the effect of calcinate temperature on characteristics of hydroxyapatite synthesized from the fish scale (FHAp). The FHAp calcined at different temperatures starting from 100 up to 300 °C. The structures of FHAP were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The analytical results show that the FHAp quality increased as the calcin temperature increased. The FHAp displayed excellent characteristics in term of particle size, morphology and properties and crystalinity after calcined at 300 °C, FHAp 300. From this study, it founded that 300 °C is the lowest calcin temperature could be applied to synthesize high quality of HAp from fish scale biowaste.

Abstract: Organic-inorganic hybrid silica were prepared via surfactant-mediated assembly of 1,2-bis (triethoxysilyl) ethane in a modified stöber process. Factors that affect the size of silica particles were investigated in detail. It is found that larger silica spheres are obtained under lower surfactant concentration, higher ammonia concentration and lower synthesis temperature; The size and dispersibility of silica particles also depend strongly on the amount of water in the mixture.