Browsing by Author "Mostafazadeh, A."

Now showing 1 - 5 of 5

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Disposable cartridge biosensor platform for portable diagnostics
(SPIE , 2017) Yaras, Y. S.; Cakmak, O.; Gunduz, A. B.; Saglam, G.; Olcer, S.; Mostafazadeh, A.; Baris, I.; Civitci, F.; Yaralıoğlu, Göksen Göksenin; Urey, H.; Electrical & Electronics Engineering; YARALIOĞLU, Göksen Göksenin
We developed two types of cantilever-based biosensors for portable diagnostics applications. One sensor is based on MEMS cantilever chip mounted in a microfluidic channel and the other sensor is based on a movable optical fiber placed across a microfluidic channel. Both types of sensors were aimed at direct mechanical measurement of coagulation time in a disposable cartridge using plasma or whole blood samples. There are several similarities and also some important differences between the MEMS based and the optical fiber based solutions. The aim of this paper is to provide a comparison between the two solutions and the results. For both types of sensors, actuation of the cantilever or the moving fiber is achieved using an electro coil and the readout is optical. Since both the actuation and sensing are remote, no electrical connections are required for the cartridge. Therefore it is possible to build low cost disposable cartridges. The reader unit for the cartridge contains light sources, photodetectors, the electro coil, a heater, analog electronics, and a microprocessor. The reader unit has different optical interfaces for the cartridges that have MEMS cantilevers and moving fibers. MEMS based platform has better sensitivity but optomechanical alignment is a challenge and measurements with whole blood were not possible due to high scattering of light by the red blood cells. Fiber sensor based platform has relaxed optomechanical tolerances, ease of manufacturing, and it allows measurements in whole blood. Both sensors were tested using control plasma samples for activated-Partial-Thromboplastin-Time (aPTT) measurements. Control plasma test results matched with the manufacturer’s datasheet. Optical fiber based system was tested for aPTT tests with human whole blood samples and the proposed platform provided repeatable test results making the system method of choice for portable diagnostics.
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LoC sensor array platform for real-time coagulation measurements
(IEEE, 2014) Cakmak, O.; Kılınç, N.; Ermek, E.; Mostafazadeh, A.; Elbuken, Ç.; Yaralıoğlu, Göksen Göksenin; Urey, H.; Electrical & Electronics Engineering; YARALIOĞLU, Göksen Göksenin
This paper reports a MEMS-based sensor array enabling multiple clot-time tests in one disposable microfluidic cartridge using plasma. The versatile LoC (Lab-on-Chip) platform technology is demonstrated here for real-time coagulation tests (activated Partial Thrompoblastin Time (aPTT) and Prothrombin Time (PT)). The system has a reader unit and a disposable cartridge. The reader has no electrical connections to the cartridge, which consists of multiple microfluidic channels and MEMS microcantilevers placed in each channel. Microcantilevers are made of electro-plated nickel and actuated remotely using an external electro-coil. The read-out is also conducted remotely by a laser and the phase of the MEMS oscillator is monitored real-time. The system is capable of monitoring coagulation time with a precision estimated at 0.1sec.
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Model predictive controller as a robust algorithm for maximum power point tracking
(IEEE, 2018-01-19) Tasooji, Tohid Kargar; Mostafazadeh, A.; Usta, Ö.; Tasooji, Tohid Kargar
In the recent years, solar energy has attended the world as a clean energy. Many researchers are focused on extracting maximum power from solar panels. So, Maximum Power Point Tracking (MPPT) is used for increasing efficiency of solar PV system. This paper presents Model Predictive Controller (MPC) as a method for Maximum Power Point Tracking (MPPT) and compares it, with Perturb and Observe (P&O) and Incremental Conductance algorithm (IC) techniques. The MATLAB/Simulink and SimPower Systems software packages are used to model a proposed strategy. Simulation results show that Perturb and Observe (P&O) and Incremental Conductance algorithm (IC) techniques have limitation for tracking the exact maximum power point in transient insolation conditions. However, Model Predictive Controller (MPC) method is robust against fast varying of insolation conditions. Also, MPC method is faster than P&O and IC technique according to the simulation results.
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Optical fiber array based simultaneous parallel monitoring of resonant cantilever sensors in liquid
(Elsevier, 2016-05-01) Mostafazadeh, A.; Yaralıoğlu, Göksen Göksenin; Urey, H.; Electrical & Electronics Engineering; YARALIOĞLU, Göksen Göksenin
This paper reports a novel method for simultaneous resonance monitoring of MEMS cantilevers using phase based dynamic measurements without any electrical connections to the sensor array. MEMS cantilevers are made of electroplated nickel and actuated remotely with magnetic field using an electro-coil. To our knowledge this is the first demonstration of simultaneous parallel optical monitoring of dynamic mode micro-cantilever array in liquid environment. Illumination is generated using a laser source and a diffractive pattern generator, which provides 500 μW laser power per channel. A compact fiber array based pick-up was built for optical readout. Its main advantages are easy customization to different size and pitch of sensor array, and good immunity to electrical noise and magnetic interference as the photo detectors are located away from the electro-coil. The resonant frequency of the cantilever is tracked with a custom multi-channel lock-in amplifier implemented in software. For demonstrating the stability and sensitivity of the system we performed measurements using glycerol solutions with different viscosities. Measured phase sensitivity was 0.9°/1% of Glycerol/DI-water solution and the standard deviation of measured phase was 0.025°. The resulting detection limit for Glycerol/DI-water solution was 280 ppm. The proposed method showed robust results with low laser power and very good noise immunity to interference signals and environmental vibrations. The sensor technology demonstrated here is very significant as it is scalable to larger arrays for simultaneous and real- time monitoring of multiple biological and chemical agents during fluid flow.
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Voltage control of PV-FC-battery-wind turbine for stand-alone hybrid system based on fuzzy logic controller
(IEEE, 2018-01-19) Mostafazadeh, A.; Tasooji, Tohid Kargar; Şahin, M.; Usta, Ö.; Tasooji, Tohid Kargar
Most of power systems experience a transient mode. In a special case, the operation of solar panel and wind turbine is depended to solar irradiance and wind speed. In addition, maintenance dc-link voltage and output AC voltage regardless variations of wind speed and solar irradiation can be a challenging topic. In this paper, a new strategy based on the stability of dc-bus voltage for a hybrid power system is proposed. Firstly, the operation of dc-bus voltage for a stand-alone hybrid power system consists of solar panel and wind turbine is investigated. In this case, a PI controller is used to regulating at its reference value. Finally, the performance of dc-link voltage in a stand-alone hybrid system included a solar PV, wind turbine, battery, and the fuel cell is studied. Furthermore, the Fuzzy logic controller is used as a power management energy in this case. The MATLAB/Simulink and SimPowerSystems software packages are used to model a proposed stand-alone hybrid power system. Simulation results show that proposed strategy has better performance under fast variation of irradiance.