הפקולטה להנדסה ע"ש איבי ואלדר פליישמן

סמינר מחלקתי אלקטרוניקה פיזיקאלית : Liron Stern

18 בנובמבר 2018, 13:00

פקולטה להנדסה, ביניין כיתות, חדר 011

סמינר מחלקתי אלקטרוניקה פיזיקאלית : Liron Stern

סמינר לירון שטרן

You are invited to attend a lecture

Chip-scale metrology: taming atoms, frequency combs and cavities

:By

Liron Stern

National Institute of Standards and Technology (NIST), Time & Frequency division, 325 Broadway Boulder CO, USA

Metrology, the science of measurement, strives to push the limits of human ability to measure quantities such as time, frequency, distance, temperature and mass. This ongoing global effort provides us with a reference “ruler” which is crucial both for understanding the fundamental nature of our universe, as well as an enabling and driving new technologies. Central to such measurements are quantum sensors, such as atomic clocks, magnetometers and superconducting voltage standards which are continuously driving today’s technological revolutions. Nowadays, we are witnessing a universal endeavor to miniaturize such “measuring machines” with two prime motivations: understanding the fundamentals of light-matter interactions at these extreme limits, and enabling new applications in disciplines such as telecommunication, space exploration and medical devices.

In this talk, I will present how we move forward to enable chip-scale frequency metrology. First, I will introduce the recently discovered microresonator based Kerr-soliton frequency combs, and experiments and calculations where we have used these as a spectroscopic tool to directly interact with atomic vapour. I will present experimental results where we construct a new type of micro-machined atomic vapour cells where diffractive optics are merged with atomic physics. I will describe how these devices map atomic states to the spatial distribution of diffracted light, and how we can utilize these effects to allow offset frequency locks with high stability. Finally, I will present a miniaturized cavity with a quality factor of a billion, interfaced with an atomic micromachined atomic cell, providing ~100 Hz of linewidth and stable optical frequency. To conclude, I will show how interfacing atoms, Kerr-combs, and miniaturized cavities paves the way to a fully chip-scale metrology system, and discuss the huge impact such system may cast on science and technology.

On Sunday, November 18, 2018, 13:00

Room 011, Kitot building

פעילות מדעית לילדי ארגון בוגרי הנדסה 04.12.18

04 בדצמבר 2018, 9:00

חדר 206 בניין וולפסון בפקולטה להנדסה

פעילות מדעית לילדי ארגון בוגרי הנדסה 04.12.18

פעילות מדעית לילדי ארגון בוגרי הנדסה

הסיור מתאים לילדי כיתות ג-ו

יום שלישי 04.12.18

בין השעות 09:00-13:00

מספר המקומות מוגבל

הסיור הינו בתשלום בסך 25 ש"ח לכל ילד

לפרטים והרשמה לחצו כאן

סיור במעבדות של אימפקט לאבס 17.12.18

17 בדצמבר 2018, 18:45

מעבדות אימפקסטלאבס בתל אביב

סיור במעבדות של אימפקט לאבס 17.12.18

סיור במעבדות של אימפקט לאבס

Impact Labs

מעבדת המייקרים הגדולה בישראל, פועלת בשיתוף פעולה עם WeWork

מאפשרת לחבריה בחלל של 1000 מ"ר, גישה ותמיכה לטכנולוגייתhigh end

ניפגש ביום שני 17.12.18

18:45-19:15 התכנסות, מינגלינג ובו זמנית יועברו סיורים במקום

בהמשך הערב הכרות והסבר על IMPACTLABS והרצאה בנושא

פיתוח אבות טיפוס (Prototypes)

זמן משוער לסיום 20:45

לפרטים והרשמה לחצו כאן

סמינר מחלקתי אלקטרוניקה פיזיקאלית : Itay Shomroni

15 בנובמבר 2018, 15:00

פקולטה להנדסה, ביניין כיתות, חדר 011

סמינר מחלקתי אלקטרוניקה פיזיקאלית : Itay Shomroni

You are invited to attend a lecture

Quantum control with nanomechanical oscillators

:By

Itay Shomroni

Laboratoire de Photonique et de Mesure Quantique

Abstract

Quantum optomechanics, the study of mechanical motion in the quantum regime

using light, is an emerging field with applications ranging from sensing to

quantum information to exploring the classical-to-quantum transition. Although

its foundations had been laid in the 60s and 70s, quantum effects in macroscopic

mechanical motion, such as motional sideband asymmetry, radiation pressure shot

noise, and ponderomotive squeezing, have been observed only in the recent decade,

with advances in high-finesse microcavities. Mechanical oscillators based on

photonic crystals are one of the most promising systems for probing and

manipulating quantum motion, allowing efficient cooling to the motional ground

state using light as well as quantum-coherent operations. I will describe my

recent research with these systems, which includes the first demonstration of

backaction-evading measurement of mechanical motion in the optical domain. Such

measurement, originally proposed in the context of gravitational wave detection,

allows in principle arbitrary sensitivity by measuring only a single quadrature

of the motion, beating the quantum limit imposed by Heisenberg's uncertainty

relation. In addition, entering the regime of strongly-probed mechanical systems

close to their ground state has revealed novel phenomena such as interplay of

optomechanics and other Kerr-type effects, and new dynamics that can lead to

extraordinary instabilities. Quantum optomechanics is now entering a new era where full quantum control is feasible, and I will give my outlook and possible future

directions.

On Thursday, Nov 15, 2018, 15:00

Room 011, Kitot building

EE Seminar: An Efficient Simulation Tool For the Auditory System By Parallel Processing

05 בדצמבר 2018, 15:30

חדר 011, בניין כיתות-חשמל

Speaker: Yonatn Koral

M.Sc. student under the supervision of Prof. Miriam Furst-Yust and Prof. Shlomo Weiss

Wednesday, December 5^th, 2018 at 15:30

Room 011, Kitot Bldg., Faculty of Engineering

An Efficient Simulation Tool For the Auditory System By Parallel Processing

Abstract

This work presents an auditory-emulation program that simulates the auditory neural response and determines hearing level based on a parallel time-domain nonlinear solution of the cochlea. Previous such simulations used a parallel calculation of the basilar membrane velocity and then calculated the serial neural response in the temporal and longitudinal dimensions. However, this approach suffers from limited efficiency because it requires copying large arrays and performing serial computation. In contrast, the proposed approach uses the graphics processing unit to do massively parallel computing, which accelerates threshold derivation based on the neural response calculation by a factor of 80 to 400. This is valuable both to calculate the hearing level for single-pitch signals and spoken words (with various types of noise or in silence) and to determine the benefit of different hearing aids to the hearing impaired.

EE Seminar: New Paradigms for Cryptographic Hashing

19 בנובמבר 2018, 15:00

חדר 011, בניין כיתות-חשמל

(The talk will be given in English)

Speaker: Dr. Ilan Komargodski
Cornell Tech.

Monday, November 19^th, 2018
15:00 - 16:00

Room 011, Kitot Bldg., Faculty of Engineering

New Paradigms for Cryptographic Hashing

Abstract

Cryptographic hash functions are the basis of many important and far reaching results in cryptography, complexity theory, and beyond. In particular, hash functions are the primary building block of fundamental applications like digital signatures and verifiable computation, and they are the tool underlying the proofs-of-work which drive blockchains.

Because of the central role of cryptographic hash functions in both theory and practice, it is crucial to understand their security guarantees, toward basing applications on the minimal possible notion of security. Indeed, there are many ways to formalize the security requirement of a hash function; each way is sufficient for different applications. Also, there are many candidate hash functions, offering various trade-offs between security, efficiency, and other desirable properties.

In this talk, I will present an application [Komargodski-Naor-Yogev, FOCS 2017] of a relatively weak notion of hashing (collision resistance) that goes well beyond cryptography into a fundamental problem in the intersection of complexity theory and combinatorics -- the Ramsey problem. This will lead us to new emerging aspects of hash functions, including relaxed security notions and their applications, addressing a recent attack on SHA-1. I will conclude with several exciting open problems and challenges.

Short Bio

Ilan Komargodski is a postdoctoral researcher at the cryptography and security group at Cornell Tech, hosted by Prof. Rafael Pass. His research interests are in cryptography and its interplay with other fields in the foundations of computer science. He earned his Ph.D. in computer science from the Weizmann Institute of Science in 2017, where he was advised by Prof. Moni Naor.

EE Seminar: STRING DAMPING: AN EXAMPLE IN ASYMPTOTIC CONTROL THEORY

18 בנובמבר 2018, 15:00

חדר 011, בניין כיתות-חשמל

(The talk will be given in English)

Speakers: ALEXANDER OVSEEVICH AND ALEKSEY FEDOROV

Russian Academy of Sciences for Machine Learning at ETH Zurich

SUNDAY, November 18^th, 2018
15:00 - 16:00

Room 011, Kitot Bldg., Faculty of Engineering

STRING DAMPING: AN EXAMPLE IN ASYMPTOTIC CONTROL THEORY

Abstract

We study the problem of the minimum-time damping of a closed string under a bounded load, applied at a single _xed point. A constructive feedback control law is designed, which allows to bring the system to a bounded neighbourhood of the terminal manifold. The law has the form of the dry friction at the point, where the load is applied. The motion under the control is governed by a nonlinear wave equation. The existence and uniqueness of solution of the Cauchy problem for this equation are proved. The main result is the asymptotic optimality of the suggested control law.

Keywords maximum principle, reachable sets, linear system MSC 2010: 93B03, 93B07, 93B52.

Bio
AO born in Moscow, Russia in 1951, graduated From the mathematical department of the Moscow State University in 1973, and in 1976 defended PhD dissertation on number theory in the Mathematical Institute of the academy of sciences.

He obtained the next degree (Dr. of phys.-math. sc.) in 1997 from the Institute for Problems in mechanics, RAS for work in control theory. Worked in many areas of mathematics, from number theory to mathematical physics.

At present affiliated with the Institute for Problems in mechanics, RAS. Institute for Problems in Mechanics, Russian Academy of Sciences, 119526, Vernadsky av., 101/1, Moscow, Russia, ovseev@ipmnet.ru Russian Quantum Center, aleksey.fedorov@lptms.u-psud.fr

School of Mechanical Engineering Tamar Domb

15 במאי 2019, 14:00 - 15:00

בניין וולפסון חדר 206

School of Mechanical Engineering Tamar Domb

School of Mechanical Engineering Seminar
Wednesday, May 15, 2019 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Active and Passive Flow Control Methods Applied on a Quarter Truck Model

Tamar Domb

M.Sc. student of Prof. Avi Seifert

The need to reduce the fuel consumption of road vehicles, in particular of heavy ones, is an important scientific and technological challenge, due to its economic, environmental and political impact. Driving at highway speeds is a highly wasteful process, because the aerodynamic drag (airflow resistance) is increasing in a cubic fashion with the driving speed.

The present research deals with advanced methods to reduce the fuel consumption of heavy vehicles driving at highway permitted speeds. The research went beyond the currently available methods, that are passive (e.g., shaping) that modify the shape of the trailer end. Our methods are termed “active” in the sense that they use a system of devices that consume energy, but can be operated only when needed and in a controlled method that can be adjusted to the changing driving conditions and more importantly, be significantly smaller than current devices while being at least as effective.

The main goal of the research was to study the effects of the shape of a drag reducing device, that is mounted at the rear-end of a truck-trailer configuration, and mapping the stream-wise vortices that develop at the corners of the drag reducing device.

The model used in this research is a quarter model of a 1:6 scale of a real truck, mounted to two of the wind tunnels walls. The experiments included a few main configurations, and the baseline configuration. Passive flow control methods were added in the form of add-on devices mounted to the model's back wall. One add-on device was also used with two methods of active flow control: Flow suction and a combination of flow suction with oscillatory blowing.

The wind tunnel test results showed drag reduction using the add-ons, which in some cases was increased thanks to the active flow control methods used. The most effective combination was detected and a net gain calculation was made.

School of Mechanical Engineering Naftaly Krakover

24 בדצמבר 2018, 14:00 - 15:00

בניין וולפסון חדר 206

School of Mechanical Engineering Naftaly Krakover

School of Mechanical Engineering Seminar
Monday, December 24, 2018 at 14.00
Wolfson Building of Mechanical Engineering, Room 206

Frequency Based Micro Sensors

Naftaly Krakover

Ph.D. student of Prof. Slava Krylov

Micro- and nanoelectromechanical systems (MEMS/NEMS)-based sensors are indispensable components in a large variety of products as diverse as consumer electronics, industrial, automotive and defense systems. Simplicity, manufacturability and integrability all contribute to an increasingly widespread use of these small-size low-cost devices. In the realm of high-end sensors, one of the promising and intensively researched approaches for performance improvement is based on the monitoring of the spectral characteristics of the devices. Resonant frequencies of the vibrating structure are extremely sensitive to the external stimuli such as acceleration or pressure and can be measured with high accuracy.

In this work, two different frequency-based sensing approaches ae introduced and their feasibility is demonstrated theoretically and experimentally. The first is a resonant displacement/acceleration sensor, which exploits electrostatic frequency tuning. The device incorporates a vibrating beam located in a close proximity to a quasi-statically deflecting body and interacting with it through the electrostatic field. Perturbations of the field induced by the body’s deflection affect the effective stiffness of the beam and its natural frequency. Sensitivity is enhanced by tailoring the nonlinear coupling force using fringing electrostatic fields. The feasibility of the suggested sensing scenario was demonstrated using the deflection measurement of a single crystal silicon micro scale pressurized membrane. The sensitivity of ≈ 30 Hz/kPa, which is equivalent to the displacement sensitivity of ≈ 4 Hz/nm, was registered in the experiments.

The second approach is related to the vibration-based structural health monitoring, especially in the low frequency range. One of the main challenges encountered by the MEMS vibration sensors developers is a large mismatch between typical frequencies of macro and micro scale structures. Our approach is based on a purely mechanical realization of the superheterodyne principle, which allows conversion of low frequency input signals into high frequency response. The device benefits from the inertial coupling between the translational and tilting vibrational modes of a proof mass attached to an oscillating substrate. The translational vibration creates a time-harmonic offset between the mass and the tilting axis. The frequency mixing moment emerges as a product between the inertial force and the translational displacement. The structure is distinguished by its ability to combine both sensing and signal processing functions by the same device. Our model and experimental results collectively support the feasibility of the suggested concept. Extremely low power consumption of the device makes it especially suitable for autonomous distributed sensors networks valuable for future Internet of Things (IoT) applications.

School of Mechanical Engineering Dr. Thomas Endlein

26 בנובמבר 2018, 14:00 - 15:00

בניין וולפסון חדר 206

School of Mechanical Engineering Dr. Thomas Endlein

School of Mechanical Engineering Seminar
Monday, November 26, 2018 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

To stick without getting stuck – control of attachment forces in animal adhesive pads

Dr. Thomas Endlein

Max Planck Institute for Polymer Research, Department of Physics at Interfaces, Mainz, Germany.

Many animals, including geckos, frogs, spiders and insects have evolved specialised adhesive pads on their feet in order to climb smooth or slippery surfaces. These pads show great promise for biomimetic applications as they have several advantages over man-made adhesives: they stick to a variety of surfaces, including smooth, rough, hydrophilic, hydrophobic and even wet ones. Furthermore, despite being inherently sticky, the pads 'self-clean' without the need for grooming. Last, animal pads are highly dynamic, i.e. animals can switch from very firm attachment to efficient detachment within milli-seconds. No currently known technical adhesive can achieve this. Using ants and frogs as model systems, I will present how these animals can cope with different challenges, like attaching to smooth and rough surfaces, climbing vertical and overhanging substrates, carrying extra loads and staying attached when suddenly perturbed. If we understand how animal adhesive pads work, we might be able to design technical adhesives which would function in similar ways.

עמודים