the purpose of this study was to investigate the deposition of the hydroxyapatite (ha) coating via the electrophoresis procedure. the ha deposition was performed in an ethanol, methanol, acetone and isopropanol suspension. methanol was found to be the best deposition media. among the different environmental conditions, including the encapsulation of the samples under two vacuum types of pressur...

asphaltene precipitation and deposition is a serious problem in many iranian fields. the deposited asphaltene results in partial or total blockage of the wellbore and wellstring reducing or completely seizing oil production. this paper studies the asphaltene problem and mitigation methods in wellstring systematically. it presents new approach based on the combination of thermodynamic modeling o...

the suitability of three vapor deposition techniques for pore size modification was evaluated using polycarbonate track etched membranes as model supports. a feature scale model was employed to predict the pore geometry after modification and the resulting pure water flux. physical vapor deposition (pvd) and pulsed plasma-enhanced chemical vapor deposition (pecvd), naturally, form asymmetric na...

In this study, asphaltene deposition from crude oil has experimentally and theoretically been studied using a test loop and an accurate temperature monitoring during a laminar flow. The effects of oil velocity and surface temperature on the thickness of asphaltene deposition were investigated. The results show that asphaltene deposition thickness increases by increasing surface temperature. As ...

This paper is concerned with asphaltene deposition in fluid flowing through pipelines. Brownian diffusion and drag, gravitational, thermophoresis, buoyancy, and shear removal are considered as possible mechanisms in the asphaltene deposition process. The thermo-physical properties of the fluid were obtained from Iranian oil fields. A model was used in the pipeline deposition modeling to predict...

An experiment set-up is used to study wall deposition rate of particles on a rough surface in a turbulent channel flow. Deposition velocities for three classes of particles, namely, spherical glass particles, irregular shape polymer particles, and fibrous silicon particles are studied. The particle concentration at the test section was measured with the aid of an isokinetic probe in conjunction...

In this paper, kinetics of DC electrophoretic deposition EPD of carbon nanotubes CNTs is investigated. Carbon nanotubes suspended in pure ethanol with addition of magnesium nitrate was used as deposition media. The effect of main EPD parameters such as deposition time, applied voltage and the CNT concentration on deposit yield was investigated. The variation of current density vs. time and the ...

Asphaltene precipitation and deposition is a serious problem in many Iranian fields. The deposited asphaltene results in partial or total blockage of the wellbore and wellstring reducing or completely seizing oil production. This paper studies the asphaltene problem and mitigation methods in wellstring systematically. It presents new approach based on the combination of thermodynam...

nanoporous graphene which is used as nanosorbent was synthesized by chemical vapor deposition method via porous zinc oxide nanocatalyst. the reaction was carried out using methane as the carbon source and hydrogen as the carrier gas in a ratio of 4:1 at the temperature ranging 900-1050°c for 2-50 min. the product was characterized by scanning electron microscopy, transmission electron microscop...

the effect of evaporation rate on structural, morphological and optical properties of electron beam evaporated cds thin films have been investigated. cds thin film deposited by electron beam evaporation method in 12nm/min and 60nm/min evaporation rates on glass substrates. x-ray diffraction, scanning electron microscopy, uv-vis-nir spectroscopy and atomic force microscopy were used to character...