School of Mechanical Engineering Seminar
wednesday May 24.5.2023 at 14:00

Wolfson Building of Mechanical Engineering, Room 206

Acoustic-Gravity Waves – a focus on nonlinear triad interaction

Usama Kadri

senior lecturer, Cardiff University, UK

In linear water wave theory, acoustic (compression) waves are virtually decoupled from free-surface (gravity) waves, since the speed of sound in water far exceeds the maximum phase speed of gravity waves. Nevertheless, we argue theoretically that these two types of wave motion could exchange energy via nonlinear resonant triad interactions. There are two cases of interest this talk focuses on: (I) two gravity waves interacting with an acoustic mode of a comparable timescale; and (II) two acoustic modes interacting with a gravity wave of a comparable lengthscale. Using multiscale analysis cubic nonlinear Schrödinger-type evolution equations are derived. For finely tuned monochromatic waves almost all energy initially stored in the gravity waves transfers into the acoustic mode, whereas for wavepackets energy transfer becomes much less efficient. 

Implications of the result are presented for a wide range of applications: from oceanic scale microseisms (faint earth tremors), wave energy harnessing and tsunami generation and mitigation, to lab-size time reversals, standing Faraday waves in an oscillating bath, and pilot-wave quantum analogues. The talk is concluded with a discussion over pushing the boundaries towards the derivation of general evolution equations. 

 Biography
I am an Aerospace Engineer, an Applied Mathematician, and a Science Communicator. My research focus lies in the area of fluid dynamics and nonlinear phenomena. Specifically, it is concerned with studying “acoustic–gravity waves”, which I employ to address most challenging questions with high impact on science and society. Recently I have focused on the early detection and mitigation of tsunami, in collaboration with the UNESCO; Covid-19; the missing Malaysian Airplane MH370; and Quantum Analogues. My approach is theoretical mathematical, combined with numerical modelling, lab experiments, and field-data analysis.

I obtained a B.Sc. and M.Sc. in Aerospace Engineering at the Technion, and a PhD in Applied Science at TU Delft (2009) under the supervision of Dist. Prof. and V. Rector R.F. Mudde, and Prof. R.V.A. Oliemans, where I also gave consultancy to oil & gas related industry (i.e., Shell, TNO), and spent some time at NTNU in Norway. I was a postdoc at CEE, Technion where I started working on acoustic-gravity waves with Prof. Micky Stiassnie (2010-2013), after which I was a Visiting Scholar at the Department of Mechanical & Aerospace Engineering, at UCSD (2013), where I met and worked with the legendary Prof. Walter Munk (Einstein of the Ocean). Then I became a Visiting Scientist & Research Fellow/postdoc, at the Department of Mechanical Engineering, MIT (2013-2015), where I worked with Prof. T.R. Akylas; and an Assistant Prof. at Haifa University and a Visiting Assistant Professor at the Department of Mathematics, MIT (2015-2016) hosted by Prof. John Bush and worked closely with Prof. C.C. Mei from CEE. I moved to the UK and joined Cardiff University’s School of Mathematics (tenured position) in 2016, keeping an honorary Research Affiliation at MIT (2016-2020). In 2018 I became a Visiting Assistant Professor at the School of Mechanical and Material Engineering, University College Dublin.  

Join Zoom Meeting

https://tau-ac-il.zoom.us/j/86497933118

You are invited to attend a lecture on Wednesday, May 3, 2023 at 12:00

Wolfson Engineering Building, Room 206

Join Zoom Meeting

https://tau-ac-il.zoom.us/j/83060796575

Overview of Electromagnetic Selective Structures

By:

Prof. Zhongxiang Shen

IEEE Antennas and Propagation Society Distinguished Lecturer

Nanyang Technological University

Singapore

Abstract

In this talk, we intend to provide a brief overview of electromagnetic selective surfaces/structures (EMSS). According to the properties of an incident electromagnetic wave, EMSS can be divided into four categories: frequency-selective structure (FSS), polarization-selective surface (PSS), angle-selective surface (ASS), and energy-selective surface (ESS). Recent developments and advances in the design of EMSS will also be briefly introduced. Finally, future opportunities in the areas of the design and analysis of EMSS will be suggested.

Biography

Zhongxiang Shen  received the B. Eng. degree from the University of Electronic Science and Technology of China, Chengdu, China, in 1987, the M. S. degree from Southeast University, Nanjing, China, in 1990, and the PhD degree from the University of Waterloo, Waterloo, Ontario, Canada, in 1997, all in electrical engineering.

From 1990 to 1994, he was with Nanjing University of Aeronautics and Astronautics, China. He was with Com Dev Ltd., Cambridge, Canada, as an Advanced Member of Technical Staff in 1997. He spent six months each in 1998, first with the Gordon McKay Laboratory, Harvard University, Cambridge, MA, and then with the Radiation Laboratory, the University of Michigan, Ann Arbor, MI, as a Postdoctoral Fellow. In Jan. 1999, he joined Nanyang Technological University, Singapore, as an assistant professor, where he is currently a full professor. Dr. Shen served as the Chair of the IEEE MTT/AP Singapore Chapter in 2009. From Jan. 2010 to Aug. 2014, he was the Chair of IEEE AP-S Chapter Activities Committee. From July 2014 to December 2018, he served as the Secretary of IEEE AP-S. He was an elected AdCom member of the IEEE AP-S from Jan. 2017 to Dec. 2019. He served as an Associate Editor of the IEEE Transactions on Antennas and Propagation from July 2016 to July 2022. From Jan. 2021 to Dec. 2023, he is a Distinguished Lecturer of the IEEE AP-S. Prof. Shen is currently the Editor-in-Chief of IEEE Open Journal of Antennas and Propagation.

Prof. Shen is an IEEE Fellow. His research interests include small and planar antennas for various wireless communication systems, analysis and design of frequency-selective structures and absorbers, hybrid numerical techniques for modeling RF/microwave components and antennas. He has authored more than 220 journal papers (among them 170 were published in IEEE Journals) and also presented nearly 200 papers at international conferences.

חברת אינטל מזמינה אתכם.ן סטודנטים וסטודנטיות לתואר ראשון ושני בהנדסה לסדנא מרתקת בעולמות הWIFI.

רשתות WiFi נמצאות בשימוש נפוץ במקומות רבים - בבית, בשדות תעופה, בבתי קפה, בבתי מלון וכן הלאה. רוב הזמן אנחנו משתמשים בסיסמה ולכן אנחנו חושבים.ות שאנחנו מוגנים.ות, אבל האם אי פעם חשבתם.ן מי עוד עשוי להיות מחובר לאותה רשת?

האם אתם.ן יכולים להבטיח שכוונותיו אינן זדוניות? האם ידעתם.ן שאפילו ב"רשתות מאובטחות" הפרטיות שלכם.ן עלולה להיות מעורפלת, ומידע עשוי להיות זמין למשתמשים זדוניים?
בסדנא הייחדית הזאת, נדגים כיצד הרגלים רעים יכולים לפגוע בפרטיות של האדם, ונתרגל מספר יכולות פריצה בסיסיות כגון שבירת הצפנת WPA2 וביצוע מתקפת Man In The Middle. 

את הסדנה מעבירים צוות מהנדסים בכירים מחטיבת האלחוט באינטל : 

• ירון קליין- טכנולוג ויזם ב-AI וסקיורטי, 12 שנים בחטיבת האלחוט באינטל במגון תפקידים -ניהול, תכנון ובנייה של מוצרים, ובעיקר מחקר סייבר במוצריembedded  WiFi ו- Bluetooth
   
• אורי קופפרשמיד- בעל תואר B.Sc בהנדסת חשמל ומחשבים, 16 שנים בחטיבת האלחוט באינטל, 5 מתוכן בתחום הסייבר בטכנולוגיות WiFi ו- Bluetooth.
   
• צחי רווה- בעל תואר ראשון ושני במדעי המחשב, 8 שנים בחטיבת האלחוט באינטל, 4 מתוכן בתחום הסייבר בטכנולוגיות WiFi ו- Bluetooth

הקדימו להירשם- וניפגש!

מתי? : 22.05.23

שעות: ניתן להירשם לאחד מהסשנים 10:00-12:00 או 14:00-16:00

איפה?: משרדי אינטל פתח תקווה, החרוצים 7, פתח תקווה

שימו לב! מספר המקומות מוגבל- אנא הקפידו להירשם בהקדם. 

(The talk will be given in English)

Speaker:     Prof. Dan Halperin

School of Computer Science, Tel Aviv University

 011 hall, Electrical Engineering-Kitot Building 

Monday, May 08^th, 2023

15:00 - 16:00

From snapping fixtures to multi-robot coordination: Geometry at the service of robotics
 

Abstract

Robots sense, move and act in the physical world. It is therefore natural that understanding the geometry of the problem at hand is often key to devising an effective robotic solution. I will review several problems in robotics and automation in whose solution geometry plays a major role. These include designing optimized 3D printable fixtures, object rearrangement by robot arm manipulators, and efficient coordination of the motion of large teams of robots. As we shall see, exploiting geometric structure can, among other benefits, lead to reducing the dimensionality of the underlying search space and in turn to efficient solutions.

Short Bio

Dan Halperin received his Ph.D. in Computer Science from Tel Aviv University, after which he spent three years at the Computer Science Robotics Laboratory at Stanford University.
He then joined the Department of Computer Science at Tel Aviv University, where he is currently a full professor and for two years was the department chair. Halperin’s main field of research is Computational Geometry and Its Applications. Application areas he is interested in include robotics, automated manufacturing, algorithmic motion planning, and 3D printing. A major focus of Halperin’s work has been in research and development of robust geometric software, in collaboration with a group of European universities and research institutes: the CGAL project and library. Halperin was the program-committee chair/co-chair of several conferences in computational geometry, algorithms and robotics, including SoCG, WAFR, ESA, and ALENEX. Halperin is an ACM Fellow and an IEEE Fellow.

‏

השתתפות בסמינר תיתן קרדיט שמיעה = עפ"י רישום שם מלא + מספר ת.ז. בטופס הנוכחות שיועבר באולם במהלך הסמינר