Project Coordinator: Prof. Nevzat G. Gençer

Project Type: TUBITAK 1001 Scientific and Technological Research Projects Funding Program

Project Duration: 30 Months

Project Start Date: October 2017

Funded Personnel: 1 Post-Doctoral Research Assistant, 3 PhD Students (half-time), 1 PhD Student (full-time), 1 MSc Student (full-time)

Harmonic Motion Microwave Doppler Imaging (HMMDI) is a novel imaging modality to image electrical and mechanical (elastic) properties of body tissues. In the proposed project, it is aimed to accelerate the elapsing time in measurements, improve the accuracy levels in HMMDI and enhance its clinical applications.

Conventional method for breast cancer diagnosis, Mammography, suffers from utilization of ionizing radiation, difficulty in imaging of dense breasts, inconclusive results and patient discomfort. Top and Gencer (2014) proposed the HMMDI method as promising hybrid method for breast cancer detection, which may overcome the limitations of the Mammography. In this method, local vibrations at a focal point are created by focused ultrasound waves. At the same time, a narrowband microwave signal is transmitted to the vibrating region. Due to local vibrations, Doppler component is observed in the spectrum of the received signal. The level of Doppler signal is related to the mechanical and electrical properties of the vibrating region. By scanning the focal region inside the breast volume, HMMDI image of the tissue can be constructed. Technical feasibility of the method has been shown via analytical (Top and Gencer, 2014), numerical and experimental (Top, 2013) (Top et. al, 2016) studies.

In this project, studies for improving accuracy level, safety and accelerating the experimental measurements will be conveyed. In order to improve the sensitivity, the main microwave component in the received signal component will be cancelled out using a active signal cancellation. Spatial accuracy will be improved via utilization of multiple antennas. To decrease the scanning time, feasibility of continuous mechanical scan of the ultrasound probe will be investigated. Numerical studies for investigating electronical scanning of the focus of ultrasound will also be done. In addition, studies for real time monitoring of system safety, such as cavitation onset, and temperature rise will be done using simulations and experimental set-ups. Moreover, by enhancing the hybridization of microwave imaging with HMMDI, dielectric distribution inside the tissue will be monitored yielding a better liability for tumor detection.

The studies will be conducted via phantom materials to investigate the feasibility of HMMDI in breast cancer diagnosis. Overcoming current encountered problems will accelerate the translation of this method to clinical studies. The study can later be developed to be adapted on cancer diagnosis over other tissues (liver, prostate, etc.).


Project Coordinator: Assist. Prof. Ozan Keysan

Project Type: TÜBİTAK/ARDEB 3501 – Career Development Program

Project Duration: 24 Months

Project Start Date: October 2017

Funded Personnel: 1 PhD (half-time) and 1 MSc (full-time) student.

Nowadays, electric motors constitute more than 50% of the total electric consumption. Variable frequency drives (VFD) have become widespread in the industry. Moreover, electric vehicles are expected to be much more common in the next decade. Several control mechanisms which have been achieved via hydraulic systems are now being replaced by electromagnetic systems in the aerospace industry. In addition, sensitive servo drives are substituting for mechanical parts rapidly in the military defense industry. The electric motors are driven by separate drives from outside which are connected via long cables in all these applications. This leads to poor power density (W/kg, W/cm3) values. These applications also require high reliability, redundancy and drives with high fault tolerance.

The aim of this project is to develop an Integrated Modular Motor Drive (IMMD) system where the electric motor and its drive are integrated into a single package. Within this scope:

  • The motor and drive will be integrated into a single package which will lead to high power density values (5 kW/liter) which will be very important in electric traction, aerospace and defense industries.
  • Both the motor and the drive will be composed of several modules operating in parallel so that the design and control will be more flexible, thermal management will be easier and redundancy of the system will increase.
  • Fault tolerance is very important in mission critical systems (aerospace, defense etc.). A fault tolerant system may continue its operation under a faulty condition with reduced power rating. The motor drive system will be able to continue its operation in case one module is faulted thanks to the modularity of the system.

In this project, new generation wide band gap (WBG) Gallium Nitride (GaN) power semiconductor devices will be utilized at high operating frequencies. By doing so, the volume of the motor drive is aimed to be reduced by 30% and the efficiency of the motor drive is aimed to be enhanced by 2% compared to the conventional drives.

All the work within the context of this project are conducted in an open-source manner and can be accessed via https://github.com/mesutto/IMMD. Moreover, the project coordinator is a member of PowerLab research group the website of which is http://power.eee.metu.edu.tr/.

A PhD student is currently working in the project and we are looking for a full-time MSc. scholarship student. 10 undergraduate students are a part of this project with several topics who are performing METU EEE STAR (http://star.eee.metu.edu.tr/current-program/) program and are also members of the sub-research group called Research League (http://power.eee.metu.edu.tr/research-league/).


Project Coordinator: Prof. Murat Eyüboğlu

Project Duration: 36 Months

Project Start Date: March 1st, 2017

Funded Personnel: 2 Full time Ph.D., 2 half time Ph.D., 1 half time MS and 1 undergraduate student. (Open positions are available)

 


Project Coordinator: Assoc. Prof. Barış Bayram (ULTRAMEMS team)

Project Duration: 36 months

Project Start Date: November 2016

Funded Personnel: 2 undergraduate and 1 MS students will engage in the research activities regarding the project.

This new microphone will provide
•Compact size
•High sensitivity
•Low energy consumption
•Durability to acceleration
•Long-term stable performance

 


Efficiency enhancement of silicon solar cells by photonic up-conversion

Project Coordinator: Assist. Prof. Selçuk Yerci

Project Duration: 24 months

Project Start Date: Jan. 2016

Funded Personnel: Project will be conducted by 1 Ph.D. and 2 M.S. students

Today, over 90% of the solar cells are produced using silicon (Si) material. There are three main reasons for the choice of Si: its relatively low material cost thanks to being the second most earth-abundant element after oxygen, its near-to-ideal band gap, and the well-developed silicon technology that allows advanced fabrication processes. However, silicon solar cells similar to all other solar cells made of single band gap material suffers from two fundamental losses: (1) non-absorbed photons with energies below the band gap of the absorber, and (2) thermalization losses due to the absorption of photons with energies well-above the band gap of the absorber. These fundamental losses can be reduced by spectrum reshaping in which a high energy photon can be converted to two or multiple lower energy photons (down-conversion) and/or two or more low energy photons can be converted to one high energy photon (up-conversion).

"In this project, we aim at increasing the efficiency of bi-facial Si solar cells by reducing the energy losses due to non-absorbed photons." said Selçuk Yerci to summarize the aim of the project. "In this study, first, we will fabricate bi-facial Si solar cells for the first time in Turkey. Next, we will fabricate up-conversion layer at the back of the bi-facial solar cells. Finally, the up-conversion efficiency of the up-converting layer will be enhanced using various photonic structures." 

Other than Asst. Prof. Selcuk Yerci, Prof. Rasit Turan, the director of GUNAM, Assoc. Prof. Ipek Kocer Guler from Cankaya University and Assoc. Prof. Sahin Kaya Ozdemir, a former graduate of EEMB (M.S. 1995 and B.S. 1992), from University of Washington at St. Louis will work as co-PI in the project.

At the moment, 2 undergraduate students are working along the direction of this topic in their STAR project. We are seeking for motivated M.S. and Ph.D. students to join our team.