Iris segmentation

The quality of eye image data become degraded particularly when the image is taken in the non-cooperative acquisition environment such as under visible wavelength illumination. Consequently, this environmental condition may lead to noisy eye images, incorrect localization of limbic and pupillary boundaries and eventually degrade the performance of iris recognition system. Hence, this study has compared several segmentation methods to address the abovementioned issues. The results show that Circular Hough transform method is the best segmentation method with the best overall accuracy, error rate and decidability index that more tolerant to ‘noise’ such as reflection

A Customer Programmable Microfluidic System

Microfluidics is both a science and a technology offering great and perhaps even revolutionary capabilities to impact the society in the future. However, due to the scaling effects there are unknown phenomena and technology barriers about fluidics in microchannel, material properties in microscale and interactions with fluids are still missing. A systematic investigation has been performed aiming to develop A Customer Programmable Microfluidic System . This innovative Polydimethylsiloxane (PDMS)-based microfluidic system provides a bio-compatible platform for bio-analysis systems such as Lab-on-a-chip, micro-total-analysis system and biosensors as well as the applications such as micromirrors. The system consists of an array of microfluidic devices and each device containing a multilayer microvalve. The microvalve uses a thermal pneumatic actuation method to switch and/or control the fluid flow in the integrated microchannels. It provides a means to isolate samples of interest and channel them from one location of the system to another based on needs of realizing the customers\u27 desired functions. Along with the fluid flow control properties, the system was developed and tested as an array of micromirrors. An aluminum layer is embedded into the PDMS membrane. The metal was patterned as a network to increase the reflectivity of the membrane, which inherits the deformation of the membrane as a mirror. The deformable mirror is a key element in the adaptive optics. The proposed system utilizes the extraordinary flexibility of PDMS and the addressable control to manipulate the phase of a propagating optical wave front, which in turn can increase the performance of the adaptive optics. Polydimethylsiloxane (PDMS) has been widely used in microfabrication for microfluidic systems. However, few attentions were paid in the past to mechanical properties of PDMS. Importantly there is no report on influences of microfabrication processes which normally involve chemical reactors and biologically reaction processes. A comprehensive study was made in this work to study fundamental issues such as scaling law effects on PDMS properties, chemical emersion and temperature effects on mechanical properties of PDMS, PDMS compositions and resultant properties, as well as bonding strength, etc. Results achieved from this work will provide foundation of future developments of microfluidics utilizing PDMS

Bubble-Driven Inertial Micropump

The fundamental action of the bubble-driven inertial micropump is investigated. The pump has no moving parts and consists of a thermal resistor placed asymmetrically within a straight channel connecting two reservoirs. Using numerical simulations, the net flow is studied as a function of channel geometry, resistor location, vapor bubble strength, fluid viscosity, and surface tension. Two major regimes of behavior are identified: axial and non-axial. In the axial regime, the drive bubble either remains inside the channel or continues to grow axially when it reaches the reservoir. In the non-axial regime the bubble grows out of the channel and in all three dimensions while inside the reservoir. The net flow in the axial regime is parabolic with respect to the hydraulic diameter of the channel cross-section but in the non-axial regime it is not. From numerical modeling, it is determined that the net flow is maximal when the axial regime crosses over to the non-axial regime. To elucidate the basic physical principles of the pump, a phenomenological one-dimensional model is developed and solved. A linear array of micropumps has been built using silicon-SU8 fabrication technology, and semi-continuous pumping across a 2 mm-wide channel has been demonstrated experimentally. Measured variation of the net flow with fluid viscosity is in excellent agreement with simulation results.Comment: 18 pages, 18 figures, single colum

Effect of start injection toward combustion, performances and emision characteristic of B20 biodiesel fuel

The utilization of the palm oil-based fuel in biodiesel fuel as alternative fuel for diesel engine has been implemented in Malaysia. However, the utilization of biodiesel is problematic because the low output power is due to incomplete combustion and incorrect vaporization characteristic. In this research, a small compression ignition engine with 320 cc four strokes direct injection has been used to carry out to characterize the combustion of biodiesel fuel. The performance and exhaust emission have been tested with blended B10 biodiesel (10% POME and 90% pure diesel) and compared with B20 biodiesel (20% POME and 80% pure diesel). The engine was tested under full load steady-state conditions at 1800rpm to 3400rpm with variable start of injection strategy (SOI). Experimental performance measurements including exhaust emissions, cylinder pressure, heat release rate, and ignition delay were conducted. As a result, the use of B20 fuel showed a reduction on engine performances; BT (0.3%), BTE (1.44%), increase of BSFC (up to 3.75%) in comparison with B10 fuels at 2400rpm engine speed. Advancing 1°CA BTDC of SOI strategy in B20 fuel is recommended, where observed an improvement of approximately 3.32% (BTE), 3.23% (BSFC) has been recorded. However, advancing the SOI in B20 fuel increases the Rate of Heat Release (ROHR). The in-cylinder pressure value is also reduced with rise of ROPR. The experimental results prove that the start of injection (SOI) strategy of the fuel has an effect on performance and emission where by advancing SOI by 1°CA bTDC improved 3.3% of BTE. Meanwhile, BSFC is reduced by 3.2% with advancing SOI by 1°CA bTDC. The NOX emission was decreased by 35.67% (approximately 10.21 g/kWh) with advancing SOI by 1°CA bTDC compared to the default SOI which is at 14°CA bTDC. Therefore, advancing the SOI has the potential to improve the engine performances compared to B10 fuels

Frequency-controlled wireless passive microfluidic devices

Microfluidics is a promising technology that is increasingly attracting the attention of researchers due to its high efficiency and low-cost features. Micropumps, micromixers, and microvalves have been widely applied in various biomedical applications due to their compact size and precise dosage controllability. Nevertheless, despite the vast amount of research reported in this research area, the ability to implement these devices in portable and implantable applications is still limited. To date, such devices are constricted to the use of wires, or on-board power supplies, such as batteries. This thesis presents novel techniques that allow wireless control of passive microfluidic devices using an external radiofrequency magnetic field utilizing thermopneumatic principle. Three microfluidic devices are designed and developed to perform within the range of implantable drug-delivery devices. To demonstrate the wireless control of microfluidic devices, a wireless implantable thermopneumatic micropump is presented. Thermopneumatic pumping with a maximum flow rate of 2.86 μL/min is realized using a planar wirelessly-controlled passive inductor-capacitor heater. Then, this principle was extended in order to demonstrate the selective wireless control of multiple passive heaters. A passive wirelessly-controlled thermopneumatic zigzag micromixer is developed as a mean of a multiple drug delivery device. A maximum mixing efficiency of 96.1% is achieved by selectively activating two passive wireless planar inductor-capacitor heaters that have different resonant frequency values. To eliminate the heat associated with aforementioned wireless devices, a wireless piezoelectric normally-closed microvalve for drug delivery applications is developed. A piezoelectric diaphragm is operated wirelessly using the wireless power that is transferred from an external magnetic field. Valving is achieved with a percentage error as low as 3.11% in a 3 days long-term functionality test. The developed devices present a promising implementation of the reported wireless actuation principles in various portable and implantable biomedical applications, such as drug delivery, analytical assays, and cell lysis devices

Piezoelectric titanium based microfluidic pump and valves for implantable medical applications

Medical devices often require precise movement of fluids. Automated implants with no need for manual handling improve patient care significantly. However, existing microfluidic devices do not fulfil the necessary specifications of size, safety, hermetic sealing, and artefact free medical imaging, as well as energy efficiency combined with adapted fluidic properties. In this work we designed, manufactured, and experimentally evaluated three piezoelectric microfluidic devices for implant automation: a diaphragm pump, a normally closed valve, and a normally open valve. All devices are made of titanium, minimizing the risk of artefacts in medical imaging. They have similar form factors and use the same actuation method. For the later, a specific mounting process of the piezo actuator enables outstanding fluidic performance during experimental evaluations. The titanium micropumps show a maximal flow of (14 ± 2.2) ml/min and pressure build-up of 75 kPa. The normally closed valve’s leakage rates are extremely low with less than 1 μL/min. Detailed investigations further include the actuator stroke, a lifetime study for normally open valves, and a numerical and experimental evaluation of the normally closed valve’s spring foil. The introduced titanium technology platform is ideally suited for system integration accounted for by the use of the same actuation principle and the similar form factor and a simple design. The development of small, smart, and energy efficient implants for improved treatment is possible based on the introduced platform

Real-time and reversible light-actuated microfluidic channel squeezing in dye-doped PDMS

partially_open6The azobenzene chromophore is used as a functional dye for the development of smart microfluidic devices. A single layer microfluidic channel is produced, exploiting the potential of a dye doped PDMS formulation. The key advantage of this approach is the possibility to control the fluid flow by means of a simple light stimulus. Furthermore, the deformation can be controlled in time, space and intensity, giving rise to several degrees of freedom in the actuation of the channel squeezing. A future perspective will be the implementation of the microfluidic platform with structured light, to have the possibility to control the flow in a parallel and reversible manner at several points, modifying the pattern in real time.openAngelini, Angelo; Agero, Ubirajara; Ferrarese Lupi, Federico; Fretto, Matteo; Pirri, Fabrizio; Frascella, FrancescaAngelini, Angelo; Agero, Ubirajara; Ferrarese Lupi, Federico; Fretto, Matteo; Pirri, Fabrizio; Frascella, Francesc

Teaching MEMS Curriculum in Electrical Engineering Graduate Program

© ASEE 2010Microelectromechanical Systems (MEMS) refer to devices and systems in the size range of 1 micron (1 micron=10-6m) to 1000 microns. Due to their small size, MEMS technology has the advantages of low weight, low cost, low power consumption and high resolution. MEMS have found broad applications in automobile, inertial navigation, light display, optical and RF communications, biomedicine, etc. World’s MEMS market is growing rapidly each year. To meet the strong market demands on MEMS engineers and researchers, we developed MEMS curriculum in our master program in School of Engineering since Fall 2005. In this paper, we shared our experience in teaching the MEMS curriculum in master program of Electrical Engineering department. Three core courses have been developed for MEMS curriculum. The course description, goals, prerequisites, as well as the topics covered in these courses are discussed. Multimedia technology is used in the teaching to enhance the teaching results. Several MEMS course projects using ANSYS simulation are designed to help student accumulate experience in MEMS device design and simulation. Students are fascinated by the MEMS field and continue their master project/thesis research in MEMS. The MEMS curriculum attracted tremendous interest among students, and the students’ feedback on the course have been excellent. This is part of our efforts to prepare students for the future need of economy revival