Mahmoud Hussein News

CU Engineering faculty land prestigious multidisciplinary Department of Defense projects

Anonymous — Mon, 22 Apr 2024 15:24:05 +0000

CU Engineering faculty land prestigious multidisciplinary Department of Defense projects Anonymous (not verified) Mon, 04/22/2024 - 09:24

Three faculty members from the CU Boulder College of Engineering and Applied Science are conducting projects awarded through the U.S. Department of Defense’s Multidisciplinary University Research Initiative (MURI) Program.

The highly competitive research program has been enabling major contributions to military capabilities and producing commercial sector applications since 1985.

“Our college emphasizes collaboration across various research disciplines,” said Michael Gooseff, associate dean for research in the College of Engineering and Applied Science. “By prioritizing programs like MURI, we harness the diverse expertise across STEM fields to push the envelope for scientific breakthroughs.”

The three new MURI projects in the college include:

Mahmoud Hussein, professor in aerospace engineering sciences and in physics, will improve air flow across the wings and bodies of hypersonic aircraft through the use of phononic subsurface materials;
Francois Barthelat, professor in mechanical engineering, will develop and validate models for the failure of materials and structures under extreme loads; and
Scott Diddams, professor in electrical, computer and energy engineering and in physics, will examine the fundamental limits in heterodyne detection of thermal radiation with laser light.

Hussein is the main principal investigator and represents CU Boulder as the lead institution for that MURI project. Barthelat and Diddams will be collaborating on projects led by faculty from other peer institutions.

Each project will receive an average award of $7.5 million over the next five years.

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Seminar - Harmonics dispersion relation: A new fundamental theory of strongly nonlinear waves - Apr. 5

Anonymous — Tue, 02 Apr 2024 15:29:47 +0000

Seminar - Harmonics dispersion relation: A new fundamental theory of strongly nonlinear waves - Apr. 5 Anonymous (not verified) Tue, 04/02/2024 - 09:29

Mahmoud I. Hussein
Alvah and Harriet Hovlid Professor, Ann & H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder
Friday, April 5 | 10:40 a.m. | AERO 120

Abstract: Wave motion lies at the heart of many disciplines in the physical sciences and engineering. For example, problems and applications involving light, sound, heat, or fluid flow are all likely to involve wave dynamics at some level. While the theory of linear waves is fairly established, nonlinear wave motion remains a complex, often mysterious, object—particularly when the nonlinearity is strong.

For example, an unbalanced nonlinear wave distorts acutely as it travels and appears to ultimately fully lose its original shape, and in many instances the final outcome is onset of a form of instability. Inherent to this distortion is an intricate mechanism of harmonic generation manifesting in intensive time-varying exchange of energy between the harmonics that matches the wave’s ongoing nonlinear evolution in space and time.

In this work, a general theory is presented for the dispersion of these generated harmonics as they emerge and develop in a traveling nonlinear wave. The harmonics dispersion relation−derived by the theory−provides direct and exact analytical prediction of the collective harmonics spectrum in the frequency-wavenumber domain, and does so without prior knowledge of the spatial-temporal solution.

Despite its time-independence, the new relation is shown to be applicable at any temporal state of evolution of the nonlinear wave as long as the wave is balanced or has not yet reached its breaking point. The theory is applied to nonlinear elastic waves in a homogeneous rod and an extension is demonstrated to rods with a periodic array of property modulation (phononic crystal) or intrinsic resonators (elastic metamaterial). Finally, the theory is shown to provide a rigorous foundation for the analytical synthesis of solitons.

Bio: Mahmoud I. Hussein is the Alvah and Harriet Hovlid Professor at the Smead Department of Aerospace Engineering Sciences at the University of Colorado Boulder. He holds a courtesy faculty appointment in the Department of Physics and has formally served as the Engineering Faculty Director of the Pre-Engineering Program and the Program of Exploratory Studies. He received a BS degree from the American University in Cairo (1994) and MS degrees from Imperial College London (1995) and the University of Michigan‒Ann Arbor (1999, 2002). In 2004, he received a PhD degree from the University of Michigan‒Ann Arbor, after which he spent two years at the University of Cambridge as a postdoctoral research associate.

Dr. Hussein’s research focuses on the dynamics of materials and structures, especially phononic crystals and metamaterials, at both the continuum and atomistic scales. He received a DARPA Young Faculty Award in 2011, an NSF CAREER award in 2013, and in 2017 was honored with a Provost’s Faculty Achievement Award for Tenured Faculty at CU Boulder. He was awarded as PI two multi-million dollar grants, both on concepts he discovered—nanophononic metamaterials (NPMs, Phys. Rev. Lett., 2014; ARPA-E 2019-2023) and phononic subsurfaces (PSubs, Proc. R. Soc. A, 2015; ONR MURI 2024-2029).

He has co-edited a book titled Dynamics of Lattice Materials published by Wiley. He is a Fellow of ASME and has served as an associate editor for the ASME Journal of Vibration and Acoustics. In addition, he is the founding vice president of the International Phononics Society and has co-established the biennial Phononics 20xx conference series which has helped create a new multidisciplinary research community and is widely viewed as the world’s premier event in the emerging field of phononics.

Wave motion lies at the heart of many disciplines in the physical sciences and engineering. For example, problems and applications involving light, sound, heat, or fluid flow are all likely to involve wave dynamics at some level. While the theory of linear waves is fairly established, nonlinear wave motion remains a...

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PhD grad training next generation of aerospace leaders

Anonymous — Fri, 08 Dec 2023 22:41:02 +0000

PhD grad training next generation of aerospace leaders Anonymous (not verified) Fri, 12/08/2023 - 15:41

Jeff Zehnder

Three "generations" of PhDs: Asst. Prof. Michael Frazier (center); with his PhD advisor, CU Boulder Prof. Mahmoud Hussein (right); and Frazier's current PhD student, Jack Pechac (left).

Michael J. Frazier (AeroEngr MS’11, PhD’15) discovered the dream engineering job he never knew he was looking for: university professor.

In high school, as an undergraduate, and even as a master’s student, Frazier was sure an industry job was in his future, but a drive for more knowledge and research sent him down a different path.

Today he is performing investigations at the frontiers of science, teaching budding young engineers, and advising doctoral students of his own.

“The research is the part of the job I love most,” Frazier said. “There are unexpected and novel results. Originally, I did not plan to complete a PhD, but am glad that I did. I get to think about a variety of subjects and pursue my own scientific interests. If I had gone into industry, my tasks may have been more routine and life might be more mundane.”

Desire to Learn

Initially, Frazier just wanted to learn more. His undergraduate degree at Embry Riddle Aeronautical University gave him a strong aerospace base, but he wanted a deeper understanding, which led him to start a master’s at the University of Colorado Boulder.

“I thought I’d gain more knowledge with the MS degree, and then negotiate for a higher starting salary when I entered an industry job. But once I experienced the research aspect of grad school, I didn’t want to stop, and so I got a PhD,” he said.

After graduation, Frazier moved to Caltech, and then ETH Zurich, for a two-year postdoc. Since 2017, he has led a research laboratory at the University of California San Diego as a tenure-track assistant professor studying metamaterials – materials that have extreme or unusual properties not found nature.

Metamaterials Research

“Nature adheres to the rules of chemistry that dictate the interactions of atoms at the small scale, which ultimately influence the observed properties of materials. Metamaterials comprise 3D-printable structural units analogous to atoms in natural materials; however, since we rather than nature control every aspect of these artificial atoms, we are able to set the rules and realize materials with performance beyond nature,” Frazier said.

It is a relatively young area of research with broad applications in many fields, including optics, acoustics, mechanics, and even biology.

“I really enjoy the physics of it. We’re investigating and discovering things nobody else has previously looked at. In science, most advances are incremental; however, the prospect of uncovering some truth or developing some insight that fosters a major leap forward is a huge personal driver.”

Example of Frazier's computational research, depicting a mechanical phase transformation within a hierarchical hexagonal lattice comprising 21,120 multi-stable elements (i.e., pistons). The phases (i.e., piston heights) can be organized into custom morphologies (e.g., a bee). The results may have implications for morphable surfaces. C. Wang and M. J. Frazier (2023), "Phase patterning in multi-stable metamaterials: Transition wave stabilization and mode conversion".

It is an area of study he started in at CU Boulder, working under Professor Mahmoud Hussein, a pioneer in phononics, a broader field of research that incorporates acoustic metamaterials.

”When Michael joined my group he was a bit uncertain in the beginning about whether an academic career would be best for him. Within just a few months, the thought started creeping into his mind. I could feel it,” Hussein said. “He progressed at a most impressive rate over the years he spent with us. By his final year, I noticed that he was enjoying going deep into his research problem and attacking every aspect of it with great detail, imagination, and rigor. At that point, it was clear to me that a faculty career was a path he could pursue with success."

Student to Teacher

Making the transition from being a PhD student to advising them has been a journey. Frazier is naturally low key and has learned the importance of being direct and intentional when leading students.

“I don’t think of myself as a pushy professor, but I make it clear when expectations are not being met,” he said. “Sometimes you need to do that so students move in the right direction and at the right speed. It took me a couple years to figure that out.”

His efforts have paid off, with his first PhD student graduating earlier this year. His second is expected to defend his doctoral dissertation in spring 2024.

“During a PhD student’s doctoral defense, it’s not only the student being judged — it’s also the professor. Your colleagues want to see that you are capable of selecting a worthy topic and executing a research plan, a major part of which is effectively guiding the graduate student up to the moment of the defense,” Frazier said.

Frazier teaches mechanics and materials classes, leading instruction in structures, solid mechanics, finite elements, and dynamics.

“I really like passing on that knowledge” he said, “Hopefully, in a manner that allows students to absorb the information faster and more deeply than when I learned it”.

His biggest challenge as a professor has been funding. Conducting research requires earning grants, and Frazier said the process can be frustrating. “I spend a lot of time conceiving what I think is an interesting proposal, and then, in writing, try to convey its intellectual merit and broader impact as well as anticipate reviewer questions. Yet, this effort may still not yield the desired result.”

He earned his first large award last year — $365,000 from the National Science Foundation to develop a new class of energy-absorbing metamaterials.

Michael J. Frazier (AeroEngr MS’11, PhD’15) discovered the dream engineering job he never knew he was looking for: university professor. In high school, as an undergraduate, and even as a master’s student, Frazier was sure an industry job was in his future, but a drive for more knowledge and research sent him down a different path...

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Cool it: Nano-scale discovery could help prevent overheating in electronics

Anonymous — Tue, 21 Sep 2021 17:04:00 +0000

Cool it: Nano-scale discovery could help prevent overheating in electronics Anonymous (not verified) Tue, 09/21/2021 - 11:04

A team of physicists at CU Boulder has solved the mystery behind a perplexing phenomenon in the nano realm: why some ultra-small heat sources cool down faster if you pack them closer together. The findings, which will publish this week in the journal Proceedings of the National Academy of Sciences (PNAS), could one day help the tech industry design speedier electronic devices that overheat less.

“Often heat is a challenging consideration in designing electronics. You build a device then discover that it’s heating up faster than desired,” said study co-author Joshua Knobloch, postdoctoral research associate at JILA, a joint research institute between CU Boulder and the National Institute of Standards and Technology (NIST). “Our goal is to understand the fundamental physics involved so we can engineer future devices to efficiently manage the flow of heat.”

A laser heats up ultra-thin bars of silicon. (Credit: Steven Burrows/JILA)

The research began with an unexplained observation. In 2015, researchers led by physicists Margaret Murnane and Henry Kapteyn at JILA were experimenting with bars of metal that were many times thinner than the width of a human hair on a silicon base. When they heated those bars up with a laser, something strange occurred.

“They behaved very counterintuitively,” Knobloch said. “These nano-scale heat sources do not usually dissipate heat efficiently. But if you pack them close together, they cool down much more quickly.”

Now, the researchers know why this happens.

In the new study, they used computer-based simulations to track the passage of heat from their nano-sized bars. They discovered that when they placed the heat sources close together, the vibrations of energy they produced began to bounce off each other, scattering heat away and cooling the bars down.

The group’s results highlight a major challenge in designing the next generation of tiny devices, such as microprocessors or quantum computer chips: When you shrink down to very small scales, heat does not always behave the way you think it should.

Atom by atom

The transmission of heat in devices matters, the researchers added. Even minute defects in the design of electronics like computer chips can allow temperature to build up, adding wear and tear to a device. As tech companies strive to produce smaller and smaller electronics, they’ll need to pay more attention than ever before to phonons—vibrations of atoms that carry heat in solids.

“Heat flow involves very complex processes, making it hard to control,” Knobloch said. “But if we can understand how phonons behave on the small scale, then we can tailor their transport, allowing us to build more efficient devices.”

To do just that, Murnane and Kapteyn and their team of experimental physicists joined forces with a group of theorists led by Mahmoud Hussein, professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. His group specializes in simulating, or modeling, the motion of phonons.

“At the atomic scale, the very nature of heat transfer emerges in a new light,” said Hussein who also has a courtesy appointment in the Department of Physics.

The researchers essentially recreated their experiment from several years before, but this time, entirely on a computer. They modeled a series of silicon bars, laid side by side like the slats in a train track and heated them up.

The simulations were so detailed, Knobloch said, that the team could follow the behavior of each and every atom in the model—millions of them in all—from start to finish.

“We were really pushing the limits of memory of the Summit Supercomputer at CU Boulder,” he said.

Directing heat

The technique paid off. The researchers found, for example, that when they spaced their silicon bars far enough apart, heat tended to escape away from those materials in a predictable way. The energy leaked from the bars and into the material below them, dissipating in every direction.

When the bars got closer together, however, something else happened. As the heat from those sources scattered, it effectively forced that energy to flow more intensely in a uniform direction away from the sources—like a crowd of people in a stadium jostling against each other and eventually leaping out of the exit. The team denoted this phenomenon “directional thermal channeling.”

“This phenomenon increases the transport of heat down into the substrate and away from the heat sources,” Knobloch said.

The researchers suspect that engineers could one day tap into this unusual behavior to gain a better handle on how heat flows in small electronics—directing that energy along a desired path, instead of letting it run wild.

For now, the researchers see the latest study as what scientists from different disciplines can do when they work together.

“This project was such an exciting collaboration between science and engineering—where advanced computational analysis methods developed by Mahmoud’s group were critical for understanding new materials behavior uncovered earlier by our group using new extreme ultraviolet quantum light sources,” said Murnane, also a professor of physics.

This research was supported by the STROBE National Science Foundation Science and Technology Center on Real-Time Functional Imaging.

Other CU Boulder coauthors on the new research include Hossein Honarvar, a postdoctoral researcher in aerospace engineering sciences and JILA and Brendan McBennett, a graduate student at JILA. Former JILA researchers Travis Frazer, Begoña Abad and Jorge Hernandez-Charpak also contributed to the study.

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Hussein, Palo win 2020 Lab Venture Challenge

Anonymous — Tue, 24 Nov 2020 19:30:40 +0000

Hussein, Palo win 2020 Lab Venture Challenge Anonymous (not verified) Tue, 11/24/2020 - 12:30

Fourteen university innovators including Smead Aerospace's Mahmoud Hussein and Scott Palo pitched their technologies at Lab Venture Challenge (LVC), a funding competition hosted by Venture Partners at CU Boulder that helps commercially-promising technologies accelerate into impactful business ventures. Judges from the local entrepreneurial ecosystem awarded a record total of 12 grants—up to $125,000 each—for the top physical science, engineering and bioscience innovations demonstrating high commercial potential, a clear path to a compelling market and strong scientific support.

Adapting to a virtual format this year, LVC was split into two categories over two days: Biosciences on Nov. 18 and Physical Sciences & Engineering on Nov. 19. Finalists delivered 8-minute pitches and navigated four minutes of Q&A from a panel of business leaders, entrepreneurs, investors and intellectual property experts.

Watch LVC Day 1: Biosciences Watch LVC Day 2: Physical Sciences/Engineering

“With $1.35 million allocated, this was the largest Lab Venture Challenge to date," said Brynmor Rees, assistant vice chancellor for Research & Innovation and managing director of Venture Partners. "More importantly, we saw incredibly strong pitches, more diversity among the finalists and ventures with high impact potential."

LVC winner Scott Palo, endowed professor of aerospace engineering and CEO of Blue Cubed, and his team are looking to bring their technology—a small, hybrid modular broadband satellite communication system—to market. Current satellites use radio frequency (or RF) systems for communications, but RFs are a fixed resource and bandwidth can be an issue. Optical, or laser communications, have nearly unlimited bandwidth and can address this scarcity problem, but weather can sometimes affect connectivity. Palo's solution combines both RF & optical systems, which provide guaranteed communication links in all-weather conditions while enabling faster rates using its patented cobalt-optical transceiver.

Zoya Popovich, distinguished professor of electrical, computer & energy and chief science officer of LumenAstra also took home an LVC prize. Alongside CEO Jim Pollock, Popovich explained how her company is developing a wearable sensor capable of measuring temperature deep below the skin, such as in cancerous tumors and in the brain post injury or stroke. Current methods like catheters and needles are invasive, uncomfortable, and inaccurate, but LumenAstra's solution offers the opposite. It's small and non-invasive while providing constant, accurate measurements and detects critical, early-warning signs before additional damage can take place.

"If it were not for the personalized attention and advice from Venture Partners, I would have never met Jim or been encouraged to join him in commercializing the ideas developed in my lab," said Popovich. "The LVC funding means that the company and product we set out to develop is not only a fun adventure, but also an obligation to provide a useful product to future users."

To prepare for the showcase, finalists were encouraged to participate in Venture Partners' Commercialization Academy customer discovery programs, such as Starting Blocks and Research-to-Market. Many also attended "Elements of Entrepreneurship" workshops, a monthly series that teaches the basics of building a high-tech, university-based startup. In addition, CU Boulder Entrepreneurs in Residence (EIRs), commercialization mentors and Venture Partners staff provided critical feedback so finalists could refine their presentations and practice engaging different business audiences in order to attract funding.

In the spring and summer of 2021, all of the LVC awardees will complete the Research-to-Market program. In addition, toward the end of the funding period, awardees will present their progress from the LVC and collaborate with EIRs, mentors and Venture Partners staff to set the commercialization path forward.

LVC funding comes from the Colorado Office of Economic Development & International Trade’s (COEDIT) AIA program, Venture Partners at CU Boulder and the Chancellor’s Innovation Fund.

Lab Venture Challenge 2020 Award Winners

Biosciences:

Zoya Popovich (pitched with CEO Jim Pollock) ($125,000)— LumenAstra: Non-invasive Compact Internal Body Thermometer
Mark Rentschler ($125,000)— Endoculus: Disposable Robotic Endoscope for Deep Enteroscopy
Brian DeDecker ($125,000) — Gene-Lock: A Novel Approach to Gene Assembly
Jerome Fox ($125,000) — Think Bioscience: Using Microbes to Drug the Undruggable
Jacob Segil ($125,000) — HeapSi: Hip Arthroscopy Surgical Instruments for Improved Patient Outcomes and Reduced Surgical Time
Xiaoyun Ding ($50,000 from Chancellor's Innovation Fund) — Modern Shennong: Acousto Thermal Shift Assay for Fast and Label-free Protein Analysis
Robert McLeod (pitched with CEO Camilla Uzcategui) ($50,000 from Chancellor'ss Innovation Fund & recipient of $1,000 Audience Choice Award) — Vitro3D: Biomimetic 3D Printed Scaffolds for Drug Discovery

Physical Sciences & Engineering:

Michael Marshak ($125,000 & recipient of $1,000 Audience Choice Award) — OTORO Energy: High Performance Battery Materials for Affordable Grid Scale Energy Storage
Michael McGehee ($125,000) — TYNT: Dynamic Smart Windows
Scott Palo ($125,000) — Blue Cubed: Hybrid Small Satellite Radio Frequency and Optical Communication System
Wil Srubar (pitched with CEO Shane Frazier) ($125,000) — Minus Materials: Reducing the Carbon Footprint of Building Materials
Mahmoud Hussein ($125,000) — Resonant Inclusions: Efficient Thermoelectric Conversion

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$2.5 million ARPA-E grant awarded to Mahmoud Hussein for transformational energy technology

Anonymous — Tue, 20 Nov 2018 22:59:00 +0000

$2.5 million ARPA-E grant awarded to Mahmoud Hussein for transformational energy technology Anonymous (not verified) Tue, 11/20/2018 - 15:59

Associate Professor and Alvah and Harriet Hovlid Professor Mahmoud Hussein has received a $2.5 million grant from the Advanced Research Projects Agency-Energy’s (ARPA‑E) latest open funding opportunity.

The award is among $98 million in funding for 40 new projects across the country being provided by the agency. These funds will support R&D projects for technologies to transform the nation’s energy system.

Hussein aims to revolutionize thermoelectrics, semiconductor devices that convert heat flow into electricity without moving parts or emitting pollutants, by creating a “nanophononic” thermoelectric device. This concept relies on a phenomenon Hussein pioneered in 2014 and has been studying theoretically within his group since then, where tiny structures added to a thin solid membrane’s top and bottom slow the flow of heat down the membrane by atomic vibrations (phonons).

The device will convert waste heat to electricity at twice the efficiency of today’s best thermoelectric devices. Since 60% of energy generated globally is wasted as heat, project success should significantly lower fuel consumption, energy costs, and global emissions.

“ARPA-E’s open solicitations serve a valuable purpose. They give America’s energy innovators the opportunity to tell us about the next big thing,” said U.S. Secretary of Energy Rick Perry. “Many of the greatest advances in human history started from the bottom up with a single person or idea, and OPEN 2018 provides a chance to open our doors to potentially the next great advancement in energy."

Hussein is the principal investigator for the project, which also includes Professor Y.C. Lee from the Department of Mechanical Engineering, Professor Ivan Smalyukh from the Department of Physics, Howard Branz, a research scientist in CU Boulder's Renewable & Sustainable Energy Institute, Colorado School of Mines physics Associate Professor Eric Toberer, and Kris Bertness, a scientist from the National Institute of Standards and Technology.

More information:

Department of Energy Announces $98 Million for 40 Transformative Energy technology Projects

Gardner, Bennet Announce $4.5 Million in Energy Innovation Grants for Colorado Universities

Associate Professor Mahmoud Hussein has received a $2.5 million grant from the Advanced Research Projects Agency-Energy’s (ARPA‑E) latest open funding opportunity.

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"Phononics: An Emerging Interdisciplinary Field with Roots in Smead Aerospace" Seminar - Oct. 29

Anonymous — Thu, 25 Oct 2018 15:25:19 +0000

"Phononics: An Emerging Interdisciplinary Field with Roots in Smead Aerospace" Seminar - Oct. 29 Anonymous (not verified) Thu, 10/25/2018 - 09:25

Mahmoud I. Hussein - Associate Professor, Smead Aerospace
Monday, Oct. 29, 2018 | DLC | 12:00 p.m.
Download Flyer

Abstract: Phononics is an emerging field that seeks to elucidate the nature of intrinsic mechanical motion in both conventional and artificially structured materials, and use this knowledge to extend the boundaries of physical response at either the material or structural/device level or both. The field targets primarily acoustic, elastic, and/or thermal properties and usually involves the investigation and utilization of complex wave mechanisms encompassing one or more of a diverse range of phenomena such as dispersion, resonances, dissipation, and nonlinear interactions. The field bridges multiple disciplines across applied physics and engineering, and spans multiple scales reaching the atomic scale where a rigorous definition of phonons resides–quanta of lattice vibrations.

Over the past decade, the Phononics Laboratory at Smead Aerospace, CU Boulder, has played a leading role in both the founding of institutions to help define, form, and propel the field forward, and the discovery and development of novel research concepts that lie at the heart of phonon science and engineering.

This talk will review two new paradigms developed at the Phononics Laboratory: passive flow stabilization by subsurface phonons (a concept jointly established with Sedat Biringen) and resonant thermal transport in nanophononic metamaterials. The former promises to significantly reduce drag along aircraft surfaces, and the latter is poised to double the conversion efficiency of thermoelectric devices. The talk will also present a new theory in nonlinear wave propagation that has implications not only to phononics but also to other disciplines across the physical sciences.

Bio: Mahmoud I. Hussein is an Associate Professor and the Alvah and Harriet Hovlid Professor at the Smead Department of Aerospace Engineering Sciences at the University of Colorado Boulder. He is also a faculty affiliate at the Department of Applied Mathematics, and serves as the Faculty Director of the Pre-Engineering Program at the College of Engineering and Applied Science. He received a BS degree from the American University in Cairo and MS degrees from Imperial College, London and the University of Michigan‒Ann Arbor. In 2004, he received a PhD degree from the University of Michigan, after which he spent two years at the University of Cambridge as a postdoctoral research associate.

Dr. Hussein received a DARPA Young Faculty Award in 2011 and an NSF CAREER award in 2013, and in 2017 was honored with a Provost’s Faculty Achievement Award for Tenured Faculty at CU-Boulder. He is a Fellow of ASME and an associate editor for the ASME Journal of Vibration and Acoustics. In addition, he is the founding vice president of the International Phononics Society and has co-established the Phononics 20xx conference series which is widely viewed as the world’s premier event in the emerging field of phononics

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Mahmoud Hussein named ASME Fellow

Anonymous — Mon, 21 May 2018 22:23:54 +0000

Mahmoud Hussein named ASME Fellow Anonymous (not verified) Mon, 05/21/2018 - 16:23

Mahmoud Hussein has been named a Fellow of the American Society of Mechanical Engineers (ASME).

The distinction is awarded to engineers for outstanding achievements and contributions, and has been bestowed upon only 2% of ASME’s 130,000 members.

Hussein, who is an associate professor and Smead Faculty Fellow, is being recognized for his research on wave propagation in phononic materials/structures and nonlinear wave theory, as well as his leadership in the emerging field of phononics.

Dr. Mahmoud I. Hussein has made fundamental contributions to the field of phononics and nonlinear wave propagation. Among his research accomplishments is the discovery of paradigm-shifting concepts, including resonant phonon motion in nanoscale thermal transport and controlled passive interactions between elastic phonons and instabilities in laminar fluid flow. He has also played a major role in the establishment of a scientific community for phononics through the creation of the biennial Phononics conference series and a dedicated scientific society‒the International Phononics Society. At ASME, he has been organizing the largest conference-based symposium on phononic crystals and metamaterials for over 14 years. - ASME Citation

Professor Hussein was nominated for this honor by the executive committee of the Noise Control and Acoustics Division within ASME.

Mahmoud Hussein joined the University of Colorado Boulder faculty in 2007. In addition to his service in Smead Aerospace Engineering Sciences, he is also the Faculty Director of the CU Boulder Pre-Engineering Program, and is the Vice President and co-founder of the International Phononics Society.

He will be formally inducted as a Fellow at the next ASME Congress in Pittsburgh, PA, in November 2018.

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Mahmoud Hussein's Dynamics of Lattice Materials published

Anonymous — Tue, 10 Oct 2017 23:40:33 +0000

Mahmoud Hussein's Dynamics of Lattice Materials published Anonymous (not verified) Tue, 10/10/2017 - 17:40

University of Colorado Boulder Smead Aerospace Associate Professor Mahmoud Hussein's new book has been published. Hussein is co-editor of Dynamics of Lattice Materials. Lattice materials are artificial low-weight periodic materials with unique acoustic and mechanical properties superior to conventional materials. It is an emerging area of research in which his work has played a significant role.

Key features in the book include:

Comprehensive treatment of dynamics of lattice materials and periodic materials in general, including phononic crystals and elastic metamaterials.
Provision of an in-depth introduction to elastostatics and elastodynamics of lattice materials.
Coverage of advanced topics such as damping, nonlinearity, instability, impact and nanoscale systems.
Introduction to contemporary concepts including pentamodes, local resonances and inertial amplification.
Inclusion of chapters on fast computation and design optimization tools.
Introduction of topics using simple systems and generalized to more complex structures with a focus on dispersion characteristics.

The book, which is co-edited with A. Srikantha Phani of the University of British Columbia, Canada, is intended as a reference for researchers or as a graduate-level textbook. Professor Hussein has co-authored four chapters in the book, three of which are with two of his former PhD students, Dimitri Krattiger and Osama Bilal.

The publication of the book by Wiley coincides with Mahmoud Hussein’s selection for a 2017 Provost’s Faculty Achievement Award for Tenured Faculty, which is in recognition for a research paper he published in 2014 in Physical Review Letters on a topic involving nanoscale lattice dynamics.

Professor Hussein (right) and his former PhD student and co-author Dimitri Krattiger. Dr. Krattiger has won a Smead Aerospace Graduate Research Award this year recognizing his outstanding record in research.

Provost Russell L. Moore (left) and Smead Aerospace department chair Professor Brian M. Argrow with Professor Hussein at the 2017 Fall Convocation where Hussein received a Provost’s Faculty Achievement Award for Tenured Faculty.

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Nanoscale pillars could radically improve conversion of heat to electricity, say CU Boulder researchers

Anonymous — Thu, 20 Feb 2014 22:31:55 +0000

Nanoscale pillars could radically improve conversion of heat to electricity, say CU Boulder researchers Anonymous (not verified) Thu, 02/20/2014 - 15:31

University of Colorado Boulder scientists have found a creative way to radically improve thermoelectric materials, a finding that could one day lead to the development of improved solar panels, more energy-efficient cooling equipment, and even the creation of new devices that could turn the vast amounts of heat wasted at power plants into more electricity.

The technique—building an array of tiny pillars on top of a sheet of thermoelectric material—represents an entirely new way of attacking a century-old problem, said Mahmoud Hussein, an assistant professor of aerospace engineering sciences who pioneered the discovery.

The thermoelectric effect, first discovered in the 1800s, refers to the ability to generate an electric current from a temperature difference between one side of a material and the other. Conversely, applying an electric voltage to a thermoelectric material can cause one side of the material to heat up while the other stays cool, or, alternatively, one side to cool down while the other stays hot.

Devices that incorporate thermoelectric materials have been used in both ways: to create electricity from a heat source, such as the sun, for example, or to cool precision instruments by consuming electricity.

However, the widespread use of thermoelectric materials has been hindered by a fundamental problem that has kept scientists busy for decades. Materials that allow electricity to flow through them also allow heat to flow through them. This means that at the same time a temperature difference creates an electric potential, the temperature difference itself begins to dissipate, weakening the current it created.

Until the 1990s, scientists addressed this problem by looking for materials with intrinsic properties that allowed electricity to flow more easily than heat.

“Until 20 years ago, people were looking at the chemistry of the materials,” Hussein said. “And then nanotechnology came into the picture and allowed researchers to engineer the materials for the properties they wanted.”

Using nanotechnology, material physicists began creating barriers in thermoelectric materials—such as holes or particles—that impeded the flow of heat more than the flow of electricity. But even under the best scenario, the flow of electrons—which carry electric energy—also was slowed.

In a new study published in the journal Physical Review Letters, Hussein and doctoral student Bruce Davis demonstrate that nanotechnology could be used in an entirely different way to slow the heat transfer without affecting the motion of electrons.

The new concept involves building an array of nanoscale pillars on top of a sheet of a thermoelectric material, such as silicon, to form what the authors call a “nanophononic metamaterial.” Heat is carried through the material as a series of vibrations, known as phonons. The atoms making up the miniature pillars also vibrate at a variety of frequencies. Davis and Hussein used a computer model to show that the vibrations of the pillars would interact with the vibrations of the phonons, slowing down the flow of heat. The pillar vibrations are not expected to affect the electric current.

The team estimates that their nanoscale pillars could reduce the heat flow through a material by half, but the reduction could be significantly stronger because the calculations were made very conservatively, Hussein said.

“If we can improve thermoelectric energy conversion significantly, there will be all kinds of important practical applications,” Hussein said. These include recapturing the waste heat emitted by different types of equipment—from laptops to cars to power plants—and turning that heat into electricity. Better thermoelectrics also could vastly improve the efficiency of solar panels and refrigeration devices.

The next step is for Hussein to partner with colleagues in the physics department and other institutions to fabricate the pillars so that the idea can be tested in the lab. “This is still early in the phase of laboratory demonstration but the remaining steps are within reach.”

Hussein also hopes to further refine the models he used to gain additional insight into the underlying physics. “A team of highly motivated Ph.D. students are working with me around the clock on this project,” he said.

The research was funded by the National Science Foundation.

Read the study at http://prl.aps.org/abstract/PRL/v112/i5/e055505.

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