Mohammad Kilani

Design and Analysis of a Surface Micromachined Spiral-Channel Viscous Pump

A new viscous spiral micropump which uses the surface micromachining technology is introduced. We outline the design of a spiral pump fabricated in five levels of polysilicon using Sandias Ultraplanar Multilevel MEMS Technology (SUMMiT), and presents an analytical solution of the floss field in its spiral channel. The pump characteristics are obtained experimentally for a scaled-up prototype

Force and torque characteristics for magnetically driven blood pump

Abstract Magnetically driven screw pumps were designed and fabricated for pumping biological fluids. The magnetic field simulations for three different magnetic coupling arrangements were obtained numerically. The force and torque for the three arrangements were computed. The effect of the separation gap between poles and the rotational angle on the force and torque is also presented. The pump characteristics were obtained experimentally.

Effect of Channel Aspect Ratio on the Flow Performance of a Spiral-Channel Viscous Micropump

We investigate the effect of channel aspect ratio on the flow performance of a newly introduced spiral-channel viscous micropump. An approximate 2D analytical solution for the flow field, which ignores channel curvature but accounts for a finite wall height, is first developed at the lubrication limit. A number of 3D models for spiral pumps with different aspect ratios are then built and analyzed using the finite volume method. Numerical and analytical results are in good agreement and tend to support one another The results are compared with an approximate 2D analytical solution developed for infinite aspect ratio, which neglects the effect of side walls, and assumes uniform velocity distribution across the channel width. The error in this approximation was found to exceed 5% for aspect ratios less than 10. Pressure and drag shape factors were introduced to express the effect of the pressure difference and boundary velocity on the flow rate at various aspect ratios for both moving and stationary walls

A Surface Micromachined Spiral-Channel Viscous Pump

The paper introduces a new viscous pump, called the spiral pump, which targets surface micromachining, and outlines its implementation in five levels of polysilicon using Sandia’s Ultraplanar Multilevel MEMS Technology (SUMMiT). For the purpose of analyzing the flow field in the pump, the spiral channel is approximated as an equivalent straight channel. After demonstrating the validity of this approximation for typical design, the paper presents a lubrication solution of the flow field in the channel, which is used to relate the flow rate, torque and power to rotation rate and pressure head. Experimental flow rate versus pressure data obtained from a scaled up spiral pump prototype are compared with analytical predictions, highlighting needed research efforts in modeling and analysis of the spiral pump.Copyright

Design and testing of a gentle pump with rotating magnetic field for fluids with stress-sensitive microparticles

This paper presents the design and testing of a gentle pump prototype that is operated by a rotating magnetic field. The pump targets applications in which the pumped fluid contains stress sensitive microparticles which may be damaged when subjected to the high stress levels prevalent in conventional pumps. The prototype was tested in-vitro using blood from human volunteers, and according to published international protocols for the assessment of the hemolytic properties of continuous flow blood pumps used in extracorporeal or implantable circulatory assist devices. The normalized index of hemolysis (NIH) was found to be about 0.007, which is comparable with that obtained from top ranking blood pumps available in the market today.

Development of a Multimedia Toolkit for Engineering Graphics Education

This paper focuses upon the development of a multimedia toolkit to support the teaching of Engineering Graphics Course. The project used different elements for the toolkit; animations, videos and presentations which were then integrated in a dedicated internet website. The purpose of using these elements is to assist the students building and practicing the needed engineering skills at their own pace as a part of an e-Learning solution. Furthermore, this kit allows students to repeat and view the processes and techniques of graphical construction, and visualization as much as needed, allowing them to follow and practice on their own.

A volume and inertia estimating 3D scanner for solids

The volume, center of mass, and moments of inertia of solid objects are fundamental properties used in numerous engineering and industrial applications. The paper describes the development and testing of a simple, efficient and cost effective scanner capable of estimating the surface area, volume, center of volume and inertia properties of solid objects automatically, and with high accuracy. The scanner utilizes a servomotor controlled rotary table whose rotational motion is synchronized with distance measurements obtained from a set of ultrasonic sensors located at different heights around the scanned solid. The derivation of the formulas allowing the transformation of contour coordinates to geometric properties, and their utilization in the property estimation is described. Volume and inertia estimates obtained from the scanner are presented and compared with those obtained from metrological methods.

Fabrication of NdFeB Thin Film and Its Application in MEMS

The paper measures the magnetic properties of NdFeB thin films developed under the effects of magnetic field. The samples exhibited a larger residual inductance, saturation magnetization and energy product than those treated without field or with weaker field. Magnetic MEMS was introduced with application of the NdFeB film to micro device such as pumps and gear transmission system.Copyright