DATE: Friday, January 10 - Thursday, January 23, 2020
TIME: 08:00 AM - 11:00 PM
DATE: Monday, January 20, 2020
TIME: 02:00 PM - 03:00 PM
LOCATION:Building 1, Level 4, Room 4214
Abstract:Viscoacoustic anisotropy: the wave equations and the eikonal equations.Incorporating attenuation anisotropy into the acoustic anisotropic wave and eikonal equations provides a choice for acoustic forward and inverse modeling in attenuating anisotropic media. In this seminar, Qi will talk about the dynamics and kinematics of viscoacoustic anisotropic wave propagation. In the dynamic aspect, Qi will present a relatively general description of the scalar and vector viscoacoustic orthorhombic wave equations. From such a general description, Qi will show briefly the corresponding wave equations in differential form for few classic viscoacoustic models, such as the Kelvin-Voigt, Maxwell, standard-linear-solid and Kjartansson models. To investigate the effect of attenuation and attenuation anisotropy on waveforms in multiple viscoacoustic models, Qi will illustrate the asymptotic acoustic radiations from a point source. In the kinematic aspect, Qi will show briefly the attenuating orthorhombic eikonal equation as a consequence of the viscoacoustic orthorhombic wave equations. Qi will introduce in detail the acoustic attenuating VTI eikonal equation for transverse isotropy. Qi will present a fast sweeping technique to numerically solve the acoustic attenuating VTI eikonal equation. Viscoacoustic anisotropic imaging and tomography are the main applications of the proposed wave and eikonal equations.
Biography:Qi Hao has worked on seismic anisotropy for over ten years. Before he joined KFUPM, he was a postdoc at the Department of Geosciences and Petroleum in Norwegian University of Science and Technology, where he was supervised by Dr. Alexey Stovas (NTNU) and Dr. Tariq Alkhalifah (KAUST) to study various research problems on seismic anisotropy. He has published 21 papers in peer-reviewed journals and presented over 20 expanded abstracts at international conferences such as EAGE, SEG, and IWSA.
DATE: Friday, January 24, 2020
TIME: 12:00 AM - 11:00 PM
DATE: Wednesday, January 29, 2020
TIME: 04:15 PM - 05:15 PM
LOCATION:Lecture Hall 1 (2322), Engineering and Science Hall (Building 9)
DATE: Tuesday, February 04, 2020
DATE: Wednesday, February 05, 2020
Abstract: Ion transport is ubiquitous in aqueous environments in biological, geological, chemical and environmental systems. Electrokinetics plays a very important and key role in some special cases where pore size is comparable to the screening length of electrical double layer. The applications include tight oil/gas exploration and development, radiative waste disposal, high-quality water purification, and even ion channels in cells. This talk will present (1) electrokinetic and interface theories for ion transport in micro/nanoporous media; (2) a mesoscopic numerical framework for predictions and the validations by comparisons with theories and experimental data; (3) multiscale analysis in both spacial and temporal scales for special applications.
DATE: Wednesday, February 12, 2020
Air pollution is recognized today as a major health risk. Exposure to air pollution, both ambient and household, increases a person’s risk of contracting a disease, such as atherosclerosis, stroke, chronic bronchitis, diabetes or asthma. Cities are considered as hot spots and urban populations are particularly exposed. There is, therefore, an urgent need to prepare cities to improve air quality and to adapt to climate change, incorporating this knowledge into urban planning and future design. But, air pollution is not just a health risk but also a drag on development. By causing illness and premature death, air pollution reduces the quality of life. By causing a loss of productive labor, it also reduces incomes in these countries.
DATE: Monday, February 17, 2020
TIME: 12:00 PM - 01:00 PM
LOCATION:Building 9, Lecture Hall 2
A low-carbon economy has been set as the goal by worldwide authorities. To cope with this target, we need to provide a transformative CO2 value chain. In this seminar, I will show how this could be realized by novel electrochemical CO2-to-fuel conversion platforms (or known as Power-to-Liquid) that could support high performance catalysts, enhance energy & carbon efficiencies, and eventually arrive at eco-attractive fuel productions in industry-relevant scenarios. This is achieved by research efforts at the interface between fundamental science and electrochemical engineering, across multiple scales from catalyst nanostructures at molecular scale to multiphase thermofluids at system scale.
Dr. Lu Xu obtained his B.S. and Ph.D. degrees from Department of Mechanical Engineering, University of Hong Kong in 2012 and 2017, respectively. He is currently a postdoctoral fellow in the Department of Chemistry, Yale University. His research focuses on reactor and material engineering for CO2 conversion and energy storage. So far, he has 21 publications (14 first authored) in Angewandte Chemie, Nature, ACS Energy Letters, Journal of Power Sources, Applied Energy, Renewable Energy, and 1 U.S. provisional patent.
DATE: Wednesday, February 19, 2020
DATE: Monday, February 24, 2020
Since their discovery, microelectromechanical systems (MEMS) has reached a certain level of maturity that, nowadays, they are being used in numerous daily-used machines ranging from all kind of sensors in automobiles to inertial sensors, accelerometers, and gyroscopes in the recent video games and smart mobile phones. Therefore, with the increasing demand for small sensors and actuators of distinguishing functionalities such as: large stroke, self-powering, self-calibration, high tunability, etc…, these tiny systems are expected to remain the exclusive technology in this regards for the coming years. However, with this growing demand come great challenges that these structures would have to withstand such as: the pull-in instability, all sort of internal resonances, auto-parametric resonances, mode localization, etc... Indeed, mode localization in MEMS has gathered significant attention over the past few years due to the potential to developing ultra-high sensitive micro-sensors. This dynamic phenomenon can be defined as the confinement of vibration energy to one of the modes of the coupled system in response to an external stimulus. Another phenomenon that is closely related in coupled systems exhibiting mode localization is the eigenvalue curve veering. Veering occurs when frequencies of two linearly coupled modes approach each other and deviate away interchanging the path trajectories as an external control parameter is varied. In the veering zone the respective mode-shapes of the two modes are affected by each other and get hybridized.
In this talk, the phenomenon of mode localization and mode veering will be discussed and explored for a specific MEMS design consisting of two electrostatically actuated and mechanically coupled microbeam based resonators. Continuous mechanical models will be used for the theoretical prediction of the dynamic responses of the two coupled resonators. The eigenvalue problem will be discussed under different stiffness perturbations and coupling strengths. The influence of the main input resonator electrode bias on the mode localization point will be also considered. The dynamics of the two coupled resonators will be presented and compared using their frequency response curves under different actuation, coupling strength, and output resonator stiffness perturbation scenarios.
Dr. Hassen M. Ouakad was born in Bizerte (Tunisia) in 1983. He received the B.Sc. degree, with honors, in Mechanics and Structures in 2007 from Tunisia Polytechnic School. In 2008 he received a master degree in Computational Mechanics from a joint graduate program between Tunisia Polytechnic School, Tunisia, and Virginia Tech, VA, USA. Then he joined the MEMS characterization and Motion Lab of the State University of New-York at Binghamton (NY, ISA), where he received the Ph.D. degree in 2010. In January 2011, he joined the Petroleum Engineering Department at the Texas A&M University in the Education City of Doha, State of Qatar, as a Postdoc Research Assistant. In September 2011 he joined the Mechanical Engineering Department of King Fahd University as an Assistant Professor. He got promoted to the rank of Associate Professor since April 2016. Since September 2018, he joined the Mechanical and Industrial Engineering Department of Sultan Qaboos University (SQU) in Oman as Associate Professor where he currently heads the Mechanical Systems Laboratory.
Dr. Ouakad is the recipient of the 2010 Excellence in research award granted by the Watson School of the State University of New-York at Binghamton, NY, USA. He was also awarded both the Excellence in Teaching and the Excellence in Academic Advising from the Engineering College of King Fahd University in May 2016 and April 2017 respectively. Moreover, He was awarded the Excellence in Research Award from the Deanship of Scientific Research at KFUPM back in May 2018. Dr. Ouakad developed and examined numerical/experimental techniques to characterize miniaturized devices rely on non-parallel plates electric actuating fields. He authored and co-authored more than ninety scientific articles published in highly ISI ranked international journals and referred conference proceedings. His work has been cited more than 1300 times and his H index is 15.
Dr. Ouakad is a member in the Institute of Electrical and Electronic Engineers (IEEE), and the American Society of Mechanical Engineering (ASME). He currently serves as an Associate Editor for the imminent journals of Vibration and Control, the IEEE ACCESS Journal, the Springer Microsystem Technologies. In addition, he served on few scientific committees of national and international symposiums and conferences.
DATE: Wednesday, March 11, 2020