[CCoE Notice] Upcoming Thesis Defense Announcements

Mon Nov 21 14:38:24 CST 2016

MSc DEFENSE STUDENT: Nazanin Farokh Nia
DATE: Tuesday, November 29, 2016
TIME: 3:30 PM
PLACE: Engineering building 1, Room 202
DISSERTATION CHAIR: Dr. Hadi Ghasemi
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TITLE:
Rational micro-nano structuring for thin film evaporation

Heat management in electronics and photonics devices is a critical challenge impeding
accelerated breakthrough in these fields. Among approaches for heat dissipation, thin film evaporation with micro/nano structures has been one of the most promising approaches that can address future technological demand. The geometry and dimension of these micro/nano structures directly govern the interfacial heat flux. Here, through theoretical and experimental analysis, we find that there is an optimal dimension of micro/nano structures that maximizes the interfacial heat flux by thin film evaporation. This optimal criterion is a consequence of two opposing phenomena: non-uniform evaporation flux across a liquid meniscus (divergent mass flux near three phase contact line) and the total liquid area exposed for evaporation. This general criterion is independent of the solid material and thermo-physical properties of the cooling liquid. This study paves the path for development of high-performance thermal management systems.

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MSc DEFENSE STUDENT: Seyed Mohammad Sajadi
DATE: Wednesday, November 30, 2016
TIME: 4 PM
PLACE: Engineering Building 1, Room 202
DISSERTATION Chair: Dr. Hadi Ghasemi

        [cid:7CFF27D2-EB06-4B04-A8B1-70765CB4BDE3]

TITLE:
Micro-Nano Structures for Tuned Heat Transfer
Heat localization approach has promised a new route of solar steam generation with higher efficiency than the current bulk heating approaches. In this approach, the material structure localizes the absorbed solar energy, forms a hot spot, and wicks the fluid to the hot spot for steam generation. Non-equilibrium nature of this approach minimizes energy losses leading to its superior performance to the equilibrium approaches. However, so far, the generated steam is only in the ambient pressure, not suitable for high-pressure applications. Here, we report development of a flexible artificially networked material structure highly efficient for ambient and high pressure steam generation with integrity for large-scale and various geometry implementation. The structure generates steam in the temperature range of 100-156 oC and pressure of 100-525 kPa under the solar irradiation. This material structure promises a robust and highly efficient approach for solar steam generation.

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MSc DEFENSE STUDENT: Peyman Irajizad
DATE: Tuesday, November 29, 2016
TIME: 10:00 AM
PLACE: Engineering building 1, Room 208
DISSERTATION CHAIR: Dr. Hadi Ghasemi

TITLE: Dispensing nano-pico droplets of ferrofluids

Dispensing miniature volumes of a ferrofluid is of fundamental and practical importance for diverse applications ranging from biomedical devices, optics, and self-assembly of materials. Current dispensing systems are based on microfluidics flow focusing approaches or acoustic actuation requiring complicated structures. A simple method is presented to continuously dispense the miniature droplets from a ferrofluid reservoir. Once a jet of the ferrofluid is subjected to a constrained flux through a membrane and an inhomogeneous magnetic field, the jet experiences a curvature-driven instability and transforms to a droplet. Ferrofluid droplets in the range of 0.1–1000 nl are dispensed with tunable dispensing frequencies. A model is developed that predicts the dispensed volume of the ferrofluid droplets with an excellent agreement with the measurements.

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MSc DEFENSE STUDENT: Bahareh Eslami
DATE: Monday, November 28, 2016
TIME: 12 PM
PLACE: Engineering building 2, Room E214
DISSERTATION CHAIR: Dr. Hadi Ghasemi
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TITLE:
Non-isothermal Buoyancy-Driven Exchange Flow of Miscible Fluids in inclined Pipes

We study non-isothermal buoyancy-driven exchange flow of two miscible Newtonian fluids in an inclined pipe experimentally. The cold heavy fluid is released into the hot light one in an adiabatic small-aspect-ratio pipe in the Boussinesq limit. Similar to the isothermal limit, maximal rate of the fluids interpenetration in non-isothermal case occurs at an intermediate angle, which also increases with the density difference. A novel asymmetric behavior is found in the flow never observed before in which the cold finger appears to advance faster than the hot one. This asymmetric behavior is hypothetically associated with the wall contact and the formation of a warm less-viscous film of the fluid lubricating the cold more-viscous finger along the pipe. On the other side of the pipe, a cool more-viscous film forms decelerating the hot less-viscous finger. The asymmetric behavior of the flow is finally quantified over the full range of non-isothermal experiments carried.

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BSc DEFENSE STUDENT: Munib Hasnain
DATE: Tuesday, November 22, 2016
TIME: 2:00 PM
PLACE: MD Anderson Library, Honors College, Dean’s Conference Room
DISSERTATION CHAIR: Dr. Hadi Ghasemi
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TITLE:
Magnetic extreme icephobic surfaces

Anti-icing surfaces have a critical footprint on daily lives of humans ranging from transportation systems and infrastructure to energy systems, but creation of these surfaces for low temperatures remains elusive. Non-wetting and liquid-infused surfaces have inspired routes for the development of icephobic surfaces. However, high freezing temperature, high ice adhesion strength, and high cost have restricted their practical applications. Here, we report new magnetic slippery surfaces outperforming state-of-the-art icephobic surfaces with an ice formation temperature of -34 °C, 2-3 orders of magnitude higher delay time in ice formation, extremely low ice adhesion strength (2 Pa), and stability in shear flows up to Reynolds number of 105. In these surfaces, we exploit the magnetic volumetric force to exclude the role of solid-liquid interface in ice formation. We show that these inexpensive surfaces are universal and can be applied to all types of solids (no required micro/nano structuring) with no compromise to their unprecedented properties.

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PhD DEFENSE STUDENT: Yunan Gu

DATE: Tuesday, Nov. 29. 2016

TIME: 9:30 AM

PLACE: ECE Building 1, N328 (ECE Large Conference Room)

DISSERTATION CHAIR: Dr Zhu Han

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TITLE: Matching Theory Framework for 5G Wireless Communications

The prevalence of high-performance mobile devices such as smartphones and tablets has brought fundamental changes to existing wireless networks. The growth of multimedia and location based mobile services has exponentially increased the network congestion and the demands for more wireless access. The extremely high computational complexity and communication overhead resulting from conventional centralized resource management methods is no longer suitable to capture the scale of tomorrow’s wireless networks. As a result, the resource management in next-generation networks is shifting from centralized optimization solutions to self-organizing solutions based on notions from game theory and learning. The goal of this book is to demonstrate the effectiveness of matching theory, a powerful game-theoretic and operational research framework, for solving a wide range of wireless resource allocation problems in a distributed manner. Matching theory, as a Nobel prize winning framework, has already been widely used in many economic fields. More recently,

matching theory has been shown to have a promising potential for modeling and analyzing wireless resource allocation problems due to two reasons: (1) it offers suitable models that can inherently capture many features of various wireless communication problems; (2) the ability to use notions, such as preference relations, to model complex system requirements; (3) it provides low-complexity and near-optimal matching algorithms while guaranteeing system stability.

This dissertation provides a good reference that integrates the notions from matching theory to wireless engineering, while emphasizing on how it can be applied in wireless networks from an engineer perspective. This research has the potential to contribute to the future wireless networks design, and have a long-term effect on the future wireless resource allocation problems.

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MSc DEFENSE STUDENT: Shadi Shariatnia
DATE: Monday, November 28, 2016
TIME: 2:00 PM
PLACE: Engineering building 2, RoomE214
DISSERTATION CHAIR: Dr. Hadi Ghasemi
________________________________________
TITLE:
Double diffusive effects in buoyancy driven exchange flow of miscible fluids in inclined pipes

We study double diffusion buoyancy-driven exchange flow of two miscible Newtonian fluids in an inclined pipe experimentally. Similar to the isothermal limit, maximal rate of the fluids interpenetration in double diffusion case occurs at an intermediate angle which also increases with the density difference. However, the degree of fluids mixing and diffusivity is found to increase in the double diffusion case. There has also been observed a novel asymmetric behavior in the flow which has never been observed before in the isothermal limit in which the cold finger appears to advance faster than the hot one. Backed by meticulously-designed supplementary experiments, this asymmetric behavior is hypothetically associated with the wall contact and the formation of a warm less-viscous film of the fluid lubricating the cold more-viscous finger along the pipe. The asymmetric behavior of the flow is finally quantified over the full range of experiments carried.

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