- Professor Charbel Farhat
Charbel Farhat is the Vivian Church Hoff Professor of Aircraft Structures, Chairman of the Department of Aeronautics and Astronautics, Professor of Mechanical Engineering, Professor in the Institute for Computational and Mathematical Engineering, Director of the Army High Performance Computing Research Center, and Director of the King Abdullah City of Science and Technology Center of Excellence for Aeronautics and Astronautics at Stanford University. He currently serves on the US Air Force Scientific Advisory Board and on the Space Technology Industry-Government-University Roundtable. He was selected by the US Navy recruiters as a Primary Key-Influencer, and flew with the Blue Angels during Fleet Week 2014.
Professor Farhat holds a Ph.D. in Civil Engineering from the University of California at Berkeley. He is a Member of the National Academy of Engineering, the Royal Academy of Engineering (UK) and the Lebanese Academy of Sciences, a Docteur Honoris Causa of the Ecole Centrale de Nantes, a Docteur Honoris Causa of the Ecole Normale Superieure Paris-Saclay, and a designated ISI Highly Cited Author in Engineering. He is also a Fellow of the Society of Industrial and Applied Mathematics (SIAM), the American Society of Mechanical Engineers (ASME), the International Association of Computational Mechanics (IACM), the World Innovation Foundation (WIF), the US Association of Computational Mechanics (USACM), and the American Institute of Aeronautics and Astronautics (AIAA). He was knighted in the French Order of Academic Palms and awarded the Medal of Chevalier dans l’Ordre des Palmes Académiques.
Professor Farhat and his research group at Stanford University develop mathematical models, advanced computational algorithms, and high-performance software for the design and analysis of complex systems in aerospace, automotive, marine, mechanical, and naval engineering. They contribute major advances to Simulation-Based Engineering Science. Current engineering foci in research are on the nonlinear aeroelasticity and flight dynamics of Micro Aerial Vehicles (MAVs) with flexible flapping wings and N+3 aircraft with high aspect ratio wings, layout optimization and additive manufacturing of wing structures, supersonic inflatable aerodynamic decelerators for Mars landing, and model predictive control. Current theoretical and computational emphases in research are on high-performance, multi-scale modeling for the high-fidelity analysis of multi-physics problems, high-order embedded boundary methods, uncertainty quantification, probabilistic machine learning, efficient model-order reduction for time-critical applications such as design and active control, and digital twins.
For his research in Simulation-Based Engineering Science, Professor Farhat has received several professional and academic distinctions including the Lifetime Achievement Award and Spirit of St Louis Medal from the ASME, the Ashley Award for Aeroelasticity and the Structures, Structural Dynamics and Materials Award from the AIAA, the Gordon Bell Prize and Sidney Fernbach Award from the Institute of Electrical and Electronics Engineers (IEEE) Computer Society, the Gauss-Newton Medal from the IACM, the Grand Prize from the Japan Society for Computational Engineering and Science (JSCES), the John von Neumann Medal from the USACM, the Modeling and Simulation Award from the Department of Defense, the IBM Sup’Prize Achievement Award, and the United States Presidential Young Investigator Award from the National Science Foundation and the White House. He is Editor of the International Journal for Numerical Methods in Engineering, and Editor of the International Journal for Numerical Methods in Fluids. He also serves on the editorial boards of ten other international scientific journals. He has been an AGARD lecturer on aeroelasticity and computational mechanics at several distinguished European institutions, and a plenary speaker at numerous international scientific meetings. He is the author of over 400 refereed publications on fluid-structure interaction, CFD on moving grids, computational structural mechanics, computational acoustics, uncertainty modeling and quantification, supercomputing, parallel processing, and model order reduction.
Professor Farhat was elected to the ASL in 2016 for "pioneering contributions to numerical analysis of fluid-structure interactions.”
Sample of Academician's Research
Current technology for decelerating a spacecraft from the high speed of atmospheric entry to the final stages of landing on Mars is based on parachute systems. It dates back to NASA’s Viking Program. In order to enable future exploration missions featuring sophisticated robots and safely land heavier spacecraft on Mars, this technology must be advanced to a new level of performance at supersonic speeds.
For this purpose, larger than before high-speed parachutes and inflatable drag devices are needed. For a number of reasons ranging from cost to technical considerations, the design, development, and maturing of such devices for future use at Mars cannot be performed by relying on tests only. These tasks need assistance from predictive numerical simulations based on a high-fidelity, multi-disciplinary, computational model for parachute inflation dynamics and drag prediction.
The development of such a computational model is a formidable challenge. Indeed, it must be able to predict various instabilities of a parachute such as flutter and pulsation, which may be encountered in the supersonic regime. It must be capable of assessing the influence on a parachute performance of several factors such as material and geometric porosities, the relative size of the parachute forebody with respect to its diameter, its distance from the forebody, the shape of the forebody, the line length, canopy design, and the Mach number. The computational model must also be able to predict the influence of temperature and strain rate on the stress field a parachute can experience in the supersonic regime.
In short, the development of such a computational model requires a number of innovations that Prof. Farhat and his research team at Stanford University are currently pioneering. The expected outcome of their research on this topic is a state-of-the-art modeling and simulation capability that will improve the design and performance of supersonic parachutes for Mars landing, and save costs by reducing testing.
- Professor Nesreen Ghaddar
Nesreen Ghaddar is the Endowed Qatar Chair of Energy Studies, Professor of Mechanical Engineering and the Director of the Masri Institute of Energy and Natural Resources at the American University of Beirut (AUB).
Professor Ghaddar obtained her Master’s (1982) and PhD (1985) degrees in mechanical engineering from the Massachusetts Institute of Technology, USA (MIT), and her BE (1980) from Kuwait University, Kuwait. She was AUB’s former associate provost from 2009 to 2015 and the chair of the Department of Mechanical Engineering from 2001 to 2007. She has been instrumental in the development of specialized postgraduate educational programs and laboratories in applied energy and energy studies at AUB. She is the founder and coordinator of the first online profession diploma in Green Technologies at AUB, which was initiated in 2015. She organizes the ASHRAE sponsored international conference on Efficient Building Design at AUB, which has been held every other year since 2014.
The aim of Professor Ghaddar’s research is to accelerate through research the development of technologies adaptable to warmer climates in order to reduce conventional energy consumption in buildings and mitigate bioclimatic outdoor environments. She advances energy-efficient and sustainable solutions for air quality and thermal comfort in indoor environments using novel modeling approaches coupled with experimentation. She has developed this approach to elucidate fundamental science phenomena to advance energy-efficient and hybrid air conditioning systems and develop tools for recommending clothing designs suitable for hot and humid environments. Her early work on oscillating flows in complex geometries led to an improved understanding of resonant heat transfer in which turbulence is induced at low velocities for efficient cooling. Professor Ghaddar’s pioneering research on integrating human thermal and clothing ventilation models explores an important and overlooked method for reducing energy use – cooling the occupant rather than the building. This work has progressed to the study of personalized ventilation devices to assess performance with respect to air quality and energy efficiency. She recently implemented oscillating flows in intermittent personalized ventilation to enhance comfort and save energy. She has contributed to research on particle resuspension in indoor spaces where a numerical–analytical coupled model was developed to examine resuspension under the effect of oscillatory flows, taking into account the probabilistic approach of resuspension occurrence due to turbulent bursts for different particle diameters and surface roughness. This work is being carried out to understand particle resuspension that is induced in cases of crawling babies on floors, prostration position during praying, and sleeping on a pillow where the seeded surfaces are in the vicinity of nasal and oral cavities.
Professor Ghaddar has conducted important and innovative research on displacement ventilation systems combined with chilled ceilings. She developed models which predict thermal comfort and indoor air quality determined by room air stratification height for any ratio of the chilled ceiling load to the total load, air supply conditions, and ceiling temperature. Recently, she has replaced the chilled ceiling with evaporative cooling and a liquid desiccant membrane for dehumidification, resulting in significant energy savings of up to 50%. She and her research team were the first to introduce permeable membrane liquid desiccant dehumidification directly from the space.
Professor Ghaddar has authored over 250 publications in international refereed conferences and journals, and several book chapters. She has received more than $4M in funding since joining AUB. She is a fellow of the American Society of Mechanical Engineers, the Islamic World Academy of Sciences, and the Lebanese Academy of Science. Professor Ghaddar was inducted into the Arab Women in Science Hall of Fame in 2011, and was named one of the Top 20 Most Influential Women in Science in the Islamic World by Muslim Science in 2014. She has received the Distinguished Scholar Medal from the Lebanese National Council for Scientific Research and the Abdul Hameed Shoman Award for Arab Researchers. In 2017, she and her co-authors received the Best Paper AWARD for a paper published in Science and Technology for the Built Environment, the ASHRAE Research Journal. Professor Ghaddar is an Editor of the Energy Conversion and Management Journal (2014 – present) and has recently been appointed associate editor of the Building and Environment Journal.
Professor Ghaddar was elected to the ASL on October 17, 2009 for "her scientific contributions in the areas of thermal sciences and renewable energy.”
Sample of Academician's Research
Estimation of local microclimate ventilation rate through clothing of active people is a critical issue in clothing design for comfort and protection. When different areas of the skin have different ventilation rates, local thermal comfort evaluated by skin wittedness and comfort sensation becomes important in assessing whole body comfort. A ventilation model to estimate the renewal flow rates for any limb motion configuration takes into consideration the periodic motion of the limbs and clothing, their geometric interaction at skin-fabric contact or no contact and with open or closed apertures, and the presence of wind. This work has been applied to clothing design to improve workers’ thermal comfort in transitional (unconditioned) spaces and hence increase safety and productivity. The work is also extended to modeling and experimentally determining inter-segmental ventilation where clothing segments connect between trunk and arm and the role of this ventilation in increasing human trunk ventilation. New research has recently integrated all clothing ventilation models under walking and external wind in a simplified and easy to implement comprehensive model by means of electric circuit analogy. This model is the first in literature related to clothing ventilation.
In a parallel track to the ventilation model development, a multi-node multi-segment bioheat model of young adults was developed using an accurate representation of the human arterial system, including blood flow pulsation and exact anatomical data of the arteries in the body. The model allows for modeling blood flow in body segments based on cardiac output and for accurate modeling of blood flow in extremities. This model was modified to establish an elderly bioheat model and to develop a bioheat model applicable to para- and tetraplegic persons who have altered thermoregulatory functions and thermal response due to spinal cord injury. The bioheat model represented the foundation for testing passive personal cooling vests and predicting their performance to improve workers’ productivity in hot environments. An integrated model of clothing with phase change material (PCM) and bioheat model was developed and used to optimize the PCM placement and arrangement on the vest and its appropriate melting temperature in relation to standard working durations of hot environments. Hybrid vests assessment was also done, in which desiccant was added to the PCM or PCM vest was aided with fans in hot humid climates for effective cooling.
- Professor Mohamed H. A. Hassan
Mohamed H. A. Hassan is President of the African Academy of Sciences (AAS). He is Executive Director of the Academy of Sciences for the Developing World (TWAS), Trieste, Italy, Secretary General of the Third World Network of Scientific Organizations (TWNSO) and serves on a number of committees in other organizations worldwide. He was born in the Sudan in 1947, and obtained his BSc in Mathematics from the UK in 1968, an MSc in advanced Mathematics from Oxford University in 1969 and a DPhil (Doctor of Philosophy) in Plasma Physics, in 1973, from Oxford University.
A former professor and dean of the School of Mathematical Sciences at the University of Khartoum, he received the order of scientific merit of Brazil and the order of merit of Italy. He is a fellow of TWAS, AAS, and the Islamic Academy of Science; honorary member of the Colombian Academy of Exact, Physical and Natural Sciences and the Palestine Academy of Science and Technology; corresponding member of the Belgian Royal Overseas Academy of Sciences; and foreign fellow of the Pakistan Academy of Sciences. His research areas include theoretical plasma physics, physics of wind erosion and sand transport.
Sample of Academician's Research
A main advantage of that formalism is that the collision integral is obtained in a form which is free from infinite sums of Bessel functions, and this renders the equation particularly useful for calculations in plasma kinetic theory problems.
- Dr. George Helou
George Helou is the Executive Director of the Infrared Processing and Analysis Center (IPAC), and a member of the faculty in the Physics, Math and Astronomy Division at the California Institute of Technology (Caltech) in Pasadena, CA. He is also Deputy Director of the Spitzer Science Center, and Director of the NASA Herschel Science Center. As IPAC Director, he oversees science operations for active space missions, and major astronomical archives for NASA. He has been a key participant in the research and science management for every major space infrared astronomy project launched by NASA or ESA (European Space Agency): the Infrared Astronomical Satellite (IRAS, 1983, USA/UK/Netherlands); the Infrared Space Observatory (ISO, 1995-98, ESA); the Spitzer Space Telescope, NASA’s Infrared Great Observatory launched in August 2003; the Herschel Space Observatory and the Planck Surveyor, ESA/NASA telescopes launched together in May 2009; and the Wide-Field Infrared Survey Explorer (WISE) launched by NASA in January 2010.
Dr. Helou’s research centers on understanding galaxies, in particular how they turn gas and dust into stars, and how the first generation of stars and galaxies came about and evolved into today's universe.
In pursuit of this understanding, he discovered several basic properties of galaxies. He was first to describe and explain the infrared colors of galaxies, eventually developing a family of galaxy infrared spectra in wide use today, based on an ensemble representation of the galaxy’s interstellar dust being heated by stars. He also established the existence of an unexpected tight correlation between the infrared and the radio luminosities of galaxies, and described the underlying physics, showing the correlation to result from the mechanics of star formation activity. The infrared-radio correlation is universally used today in the study of galaxies, and the physical model was validated in studies of the correlation within disks of galaxies resolved by the Spitzer Space Telescope. Exploiting the correlation, Helou identified a rare class of galaxies caught in the earliest stages, about two million years, of resurgent star formation after a long period of quiescence, leading to extreme properties. Using such insights into the behavior of galaxies, Helou and his group developed population models describing the demographics and evolution of galaxies over cosmic time scales.
Dr. Helou was born and educated in Lebanon, graduating in 1975 from the American University of Beirut with a B.S. in Physics with High Distinction and a Teaching Diploma in Science Education. He obtained a M.Sc. in 1977 and a Ph.D. in Astrophysics and Radio Science in 1980 from Cornell University. His postdoctoral studies included one year at the Arcetri Observatory in Florence, Italy, and eventually led him to the IRAS mission and infrared astronomy from space. He has published more than four hundred articles in professional journals and proceedings, lectured at over fifty international conferences, and held visiting professorships and lectureships at several European Universities including Paris, Leiden and Florence.
His awards include the NASA Exceptional Public Service Medal (2010), the NASA Public Service Medal (2004), the NASA Exceptional Achievement Medal (2001), the NASA Exceptional Service Medal (1992), the Dudley Award (1982), the Arcetri International Fellowship (1980) and the Philip K. Hitti Prize for Academic Excellence (1975). He is a member of the American Astronomical Society and of the International Astronomical Union.
Dr. Helou was elected to the ASL in 2010 for "his leadership and contribution to infrared spectroscopy of galaxies and the Spitzer Infrared Astronomy Mission." He served as President of the ASL from February 1, 2014-June 30, 2018.
Sample of Academician's Research
NGC 300 is a face-on spiral galaxy located 7.5 million light-years away in the southern constellation Sculptor. This false-color image taken by the infrared array camera on Spitzer readily distinguishes the main star component of the galaxy (blue) from its dusty spiral arms (red). The star distribution peaks in the central bulge where older stars congregate, and tapers off along the arms where younger stars reside. The dust emission here is dominated by organic compounds called polycyclic aromatic hydrocarbons (PAH), whose ubiquity in star forming galaxies was shown in 2000 by Helou et al (Astrophysical Journal Letters, 532:21).
In this 2004 study of NGC 300, Helou and collaborators (Astrophysical Journal Supplement, 154:253) reported for the first time on differences between the spatial distributions of Aromatic compound emission, 24 mm dust emission, and ionized gas regions traced by hydrogen recombination line emission (hydrogen alpha line).
The Aromatic emission highlights the rims of ionized regions, whereas the 24mm emission is more strongly peaked on those ionized regions created by intense radiation from young massive stars. The findings provide a better understanding of the excitation mechanisms of dust emission at different wavelengths and of their diagnostic significance. The details within nearby galaxies thus help decipher more distant galaxies, whose individual emission components cannot be spatially resolved, but whose infrared spectra can be readily measured.
In a 2001 study, Helou et al (Astrophysical Journal Letters, 548:73) demonstrated the critical importance of Aromatic compounds in mediating the heating of interstellar gas. Radiation from stars generates hot electrons by the photoelectric effect on dust in the interstellar medium, and these electrons then heat the gas by collisional interactions, providing the main link between radiation and gas in neutral regions. The gas then cools, primarily via fine-structure line transitions of carbon, oxygen and nitrogen in the far infrared, revealing details of its physical state and chemical composition. Aromatic compounds are particularly efficient photoelectric mediators because of their small size, and the 2001 paper demonstrated this efficiency by showing a direct scaling relation between Aromatic dust emission and C+ cooling line intensity from the neutral gas.