Micromachining technology was used to prepare chemical analysis systems on glass chips (1 centimeter by 2 centimeters or larger) that utilize electroosmotic pumping to drive fluid flow and electrophoretic separation to distinguish sample components. Capillaries 1 to 10 centimeters long etched in the glass (cross section, 10 micrometers by 30 micrometers) allow for capillary electrophoresis-based separations of amino acids with up to 75,000 theoretical plates in about 15 seconds, and separations of about 600 plates can be effected within 4 seconds. Sample treatment steps within a manifold of intersecting capillaries were demonstrated for a simple sample dilution process. Manipulation of the applied voltages controlled the directions of fluid flow within the manifold. The principles demonstrated in this study can be used to develop a miniaturized system for sample handling and separation with no moving parts.

Micromachining a miniaturized capillary electrophoresis-based chemical analysis system on a chip

Transportation of heavy and extra-heavy crude oil by pipeline: A review

Micropumping has emerged as a critical research area for many electronics and biological applications. A significant driving force underlying this research has been the integration of pumping mechanisms in micro total analysis systems and other multi-functional analysis techniques. Uses in electronics packaging and micromixing and microdosing systems have also capitalized on novel pumping concepts. The present work builds upon a number of existing reviews of micropumping strategies by focusing on the large body of micropump advances reported in the very recent literature. Critical selection criteria are included for pumps and valves to aid in determining the pumping mechanism that is most appropriate for a given application. Important limitations or incompatibilities are also addressed. Quantitative comparisons are provided in graphical and tabular forms.

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Recent advances in microscale pumping technologies: a review and evaluation

Asphaltene adsorption at solid surfaces is a ubiquitous phenomenon that begins within the production well and continues through the entire production chain. It is generally an undesirable phenomenon that causes damage within reservoirs, fouling of pipelines and transportation equipment, and fouling of refining and upgrading equipment. However, by virtue of this phenomenon, problematic asphaltenes may also be selectively removed from petroleum streams to produce partially upgraded petroleum, which has significantly improved handling, processing, and upgrading qualities. This review covers many basic aspects regarding the chemical and physical nature of asphaltenes and sorbents related to asphaltene adsorption.

Asphaltene Adsorption, a Literature Review

Heavy crude oil viscosity reduction and rheology for pipeline transportation

Rheological properties of heavy & light crude oil mixtures for improving flowability

This study investigated the different alternatives to enhance the flowability of crude oil with medium viscosity. These alternatives include the addition of water into crude oil to form water-in-oil emulsion, the addition of light petroleum product, the addition of flow improver, and a preheating technique. Temperature range of 10–50°C, water concentration range of 0–50% by volume, flow improver concentration range of 0–5000 ppm, and kerosene concentration range of 0–50% by volume were investigated in the flowability enhancement study of crude oil with medium viscosity. The flowability enhancement in terms of viscosity reduction was investigated using RheoStress RS100 from Haake. A cone–plate sensor was used with a cone angle of °4, cone diameter of 35 mm, and 0.137-mm gap at the cone tip. The addition of kerosene to crude oil improves the flowability much better than any other investigated technique.

Flow Enhancement of Medium-Viscosity Crude Oil

The interest on shedding and coalescence of sessile droplets arises from the importance of these phenomena in various scientific problems and industrial applications such as ice formation on wind turbine blades, power lines, nacelles, and aircraft wings. It is shown recently that one of the ways to reduce the probability of ice accretion on industrial components is using superhydrophobic coatings due to their low adhesion to water droplets. In this study, a combined experimental and numerical approach is used to investigate droplet shedding and coalescence phenomena under the influence of air shear flow on a superhydrophobic surface. Droplets with a size of 2 mm are subjected to various air speeds ranging from 5 to 90 m/s. A numerical simulation based on the Volume of Fluid method coupled with the Large Eddy Simulation turbulent model is carried out in conjunction with the validating experiments to shed more light on the coalescence of droplets and detachment phenomena through a detailed analysis of the aerodynamics forces and velocity vectors on the droplet and the streamlines around it. The results indicate a contrast in the mechanism of two-droplet coalescence and subsequent detachment with those related to the case of a single droplet shedding. At lower speeds, the two droplets coalesce by attracting each other with successive rebounds of the merged droplet on the substrate, while at higher speeds, the detachment occurs almost instantly after coalescence, with a detachment time decreasing exponentially with the air speed. It is shown that coalescence phenomenon assists droplet detachment from the superhydrophobic substrate at lower air speeds.

Shear driven droplet shedding and coalescence on a superhydrophobic surface

In the present study, the transient performance of the viscous micropump will be investigated numerically. The viscous micropump's operation depends mainly on viscous forces and can operate in any situation where viscous forces are dominant. All the micropump calculations are reported in nondimensional quantities, which allows for the prediction of the micropump performance, regardless of the dimensions or the fluid that is used. The effect of the microchannel height, rotor eccentricity, Reynolds number, and pump load on the transient performance of the viscous micropump has been studied in detail. The steady state performance was compared with the available experimental data and was found to be in a very good agreement. The rotor eccentricity was determined to be the parameter that affected the transient performance of the micropump the most significantly. This work provides a foundation for future research on the subject of fluid phenomena in viscous micropumps.

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Nabil Esmail

Papers

Heavy crude oil viscosity reduction and rheology for pipeline transportation

Rheological properties of heavy & light crude oil mixtures for improving flowability

Flow Enhancement of Medium-Viscosity Crude Oil

Shear driven droplet shedding and coalescence on a superhydrophobic surface

Transient behavior of the viscous micropump