School of Mechanical Engineering Michael Lahutin

19 באפריל 2017, 14:00 - 15:00

בניין וולפסון 206

ללא תשלום

School of Mechanical Engineering Michael Lahutin

School of Mechanical Engineering Seminar
Wednesday, April 19, 2017 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Active Flow Control of Wing-tip Flow Separation

Michael Lagutin

MSc Student of Prof. Avraham Seifert

School of Mechanical Engineering, Tel Aviv University, 69978 Tel Aviv, Israel

High-Lift devices, such as leading-edge slat, are commonly used in aerodynamics for increasing airfoil and wing performance at high incidence angles, mainly for takeoff and landing. However, due to complexity, weight, and cost of the deploying mechanism, the slat is not covering the full span of the wing, thus leaving the tip region “unprotected.” The slat termination creates slat-edge vortices that impinge upon the upper wing surface. The slat-edge-generated stream-wise vortices are negatively affecting the performance of the outer wing portion, resulting in local flow separations that reduce lift and significantly increase drag.

The current study deals with this problem, and was performed on an industry relevant geometry, in collaboration with Israel Aerospace Industries (IAI) and Airbus as part of the AFLONEXT EU FP7 project. The motivation of the work is to increase the robustness of the wingtip design at take-off conditions, while improving the aerodynamic efficiency at cruise conditions by closer to optimized design. The experimental model is a 3D high-lift wing configuration, which consists of swept-back (by 25°) wing with trailing edge flap fixed at 20°, leading edge slat and rounded wing tip. Active flow control (AFC) is used to delay the wingtip stall, thus improving the lift to drag ratio and allowing a steeper climb gradient. The AFC configuration was chosen based on previous studies and CFD results obtained by IAI. The work focused on steady suction AFC method, its effect was investigated through wind tunnel tests. Experiments consisted of pressure map acquiring, near wake 3D scans and a use of flow visualization techniques.

It was shown, that AFC application can delay stall, increase lift and reduce drag on the “unprotected” (by the slat) wing-tip region. The results were compared and mutually validated by CFD data obtained by IAI. It is expected that cruise optimized wingtip design will be able to provide an improvement in aerodynamic efficiency with a net benefit in fuel consumption and emissions up to 2%.

School of Mechanical Engineering Dr. Bat-El Pinchasik

07 ביוני 2017, 14:00 - 15:00

ללא תשלום

School of Mechanical Engineering Dr. Bat-El Pinchasik

School of Mechanical Engineering Seminar
Wednesday, June 7, 2017 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

A Lesson from Nature:

Underwater Reversible Adhesion using Air Capillary Bridges

Dr. Bat-El Pinchasik

Max Planck Institute for Polymer Research Mainz, Germany

Animals in nature, specifically insects, make extensive use of hydrophobic interactions for a wide variety of tasks: from gliding on the water surface through directional diving and even remaining dry underwater. Especially surprising is the ability of the leaf and ladybird beetles to walk underwater. That is, to adhere to submerged solid surfaces. By entrapping air in a hair-like hydrophobic structure they form air capillary bridges which are used to reversibly adhere and perform locomotion underwater. In order to develop a physical model to describe this mechanism, the different contributing parameters should be first identified and characterized: from structural design of the beetle’s adhesive pad to the physio-chemical properties of its cuticle. Based on numerical simulations it is possible to establish guiding principles for the design of synthetic structures for strong underwater reversible adhesion. These findings are not only important for understanding hydrophobic forces in nature but also for developing bio-inspired materials and systems for propulsion, actuation and locomotion on the micro scale. These principles can be applied for the reduction of friction in underwater transportation, control of the floatation and diving of aquatic vehicles and reduction of underwater noise.

סמינר מחילקתי

More for Less: Adaptive Labeling Payment for Online Labor Markets”

Dr. Tomer Geva – faculty member, Coller School of Management, Tel Aviv University

Abstract:

Predictive modeling has emerged as integral to the efficient operations and competitive strategies of firms across industries. Because many important predictive tasks require human intelligence to label training instances, online crowdsourcing markets have become a promising platform for large-scale labeling. However, prior research found major quality issues in such markets. In particular, very different tradeoffs arise between payment offered to labelers and the quality of labeling under different settings, and, more broadly, work quality may change over time and with changes in the competitive market settings. Further, determining the effect of labeling quality on the expected improvement in predictive performance is also challenging. Therefore, effective means for dealing with these challenges are essential for a growing reliance on these markets for predictive modelling. In this paper, we propose the new data science problem of Adaptive Labeling Payment (ALP): how to determine and continuously adapt the payment offered to crowd workers, before they undertake a labeling task, so as to produce a given predictive performance cost-effectively. We develop an ALP framework and derive a novel ALP method, which we evaluate extensively over a wide variety of market conditions. We find that our ALP method yields substantial cost savings and robust performance that can be relied on by businesses over a wide variety of settings.

(Joint work with Harel Lustiger and Maytal Saar-Tsechansky)

ההרצאה תתקיים ביום שלישי, 28.03.17 בשעה 14:00 , בחדר 206, בניין וולפסון, הפקולטה להנדסה, אוניברסיטת תל-אביב.

28 במרץ 2017, 14:00

חדר 206 בניין וולפסון

סמינר מחלקתי - אלקטרוניקה פיזיקאלת עמיחי מאירי

30 במרץ 2017, 15:00

אוניברסיטת תל אביב פקולטה להנדסה ביניין כיתות חדר 011

סמינר מחלקתי - אלקטרוניקה פיזיקאלת עמיחי מאירי

You are invited to attend a lecture

Enhancing optical nanoscopy by point-spread-function
spatial modulation

By:

Amihai Meiri

Faculty of Engineering, Bar Ilan University.

Abstract

An optical microscope has a fundamental limit of resolution: the diffraction limit, approximately 200nm for visible light. Nanoscopy methods such as STED and PALM/STORM were developed to overcome this limitation, and are capable of optical imaging with a resolution of 20– 50nm. Localization microscopy methods (PALM/STORM and single particle tracking) rely on the ability to precisely find the position of a single point emitter, where the resolution depends directly on the precision of localization.
In this talk I will describe how spatial modulation of the signal coming from a microscope can improve the capability to localize single emitters, in particular for particle tracking applications using scattering objects such as metal nanoparticles. In addition, I will show how this technique may be applicable to incoherent point sources such as fluorescent probes. This solution allows for faster, higher resolution imaging with relatively simple and low cost means, and can be used with any optical microscope.

On Thursday, March 30, 2017, 15:00
Room 011, Kitot building

School of Mechanical Engineering Inna Horovitz

24 באפריל 2017, 14:00 - 15:00

בניין וולפסון חדר 206

School of Mechanical Engineering Inna Horovitz

School of Mechanical Engineering Seminar
Monday, April 24, 2017 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Application of nano-structured solar photocatalytic membrane reactor for water treatment

Inna Horovitz

PhD Student of Prof. Hadas Mamane and Prof. Dror Avisar

Microfiltration (MF, with pores in the 0.1-10 μm range) systems offer quick and selective separation of suspended particles, larger pathogenic micro-organisms while operating at low transmembrane pressure. However, a number of contaminants, including micro-pollutants and viruses, can only be poorly removed from water by MF alone. Combining membrane filtration and advanced oxidation processes (AOP) as photocatalysis can potentially provide high water quality in a single step. Photocatalysis, which is classified as a heterogeneous AOP, is a process where a semiconductor (catalyst) is activated with sunlight irradiation following formation of highly oxidative species on the catalytic surface. A hybrid photocatalytic membrane reactor (PMR) can address multiple functions besides traditional physical separation as degradation of organic pollutants, disinfection and self-antibiofouling action. In this seminar, the efficiency of N-doped TiO₂-coated Al₂O₃MF membranes for water treatment will be presented. The photocatalytic activity (PCA) and the impact of physical and operational parameters such as operation mode (surface vs. in-pore PCA), wavelength dependence and flow rate of the suggested PMR will be presented by following the degradation of environmentally persistent pharmaceutical carbamazepine. Removal of MS2 bacteriophage, a surrogate for pathogenic waterborne viruses, by the PMR will be presented as a study case for disinfection efficiency. Virus removal in different water qualities will be addressed and correlated to the physico-chemical properties of the virus and the membrane.

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EE Seminar: No Equations, No Parameters, No Variables: Data-driven Geometry Learning for Parametrically-Dependent Dynamical Systems

(The talk will be given in English)

Speaker: Prof. Ronen Talmon,
Department of Electrical Engineering, Technion

Sunday, April 2^nd, 2017
15:00 - 16:00

Room 011, Kitot Bldg., Faculty of Engineering

No Equations, No Parameters, No Variables: Data-driven Geometry Learning for Parametrically-Dependent Dynamical Systems

Abstract

The extraction of models from data is a fundamental cognitive as well as scientific challenge. We demonstrate a geometric/analytic learning algorithm capable of creating minimal descriptions of parametrically-dependent unknown nonlinear dynamical systems. This is accomplished by the data-driven discovery of useful intrinsic state variables and parameters, in terms of which one can empirically model the underlying dynamics. We present an approach based on informed observation geometry that enables us to formulate models without first principles, as well as without closed-form equations. Our toolbox consists of data-driven hierarchical structures, multiscale bases and metrics, and intrinsic minimal data representations.

We will show applications to simulated data as well as to in-vivo recordings of neuronal activity from awake animals. The application of our technique to such recordings demonstrates its capability of capturing the relations between time-dependent neural activities in different cortical regions (motor and sensory) and associate them to behavior. Specifically, our approach gives rise to the joint organization of neurons and dynamic patterns in data-driven hierarchical structures, as well as to multi-resolution representations, discovering latent driving structures and connectivity patterns as they develop and vary over the course of weeks, days, and within individual trials. By jointly organizing neurons along time segments, our methodology reveals co-dependencies and patterns of activation related to external triggers (e.g., a tone) and behavioral events (e.g., the sequence of motor actions). In addition, we will discuss a preliminary attempt to relate the extracted model from the same animal at different stages of its training and to reveal a proficiency phase shift: from beginner through learner to expert.

‏

02 באפריל 2017, 15:00

חדר 011, בניין מעבדות-חשמל

סמינר מחלקתי - אלקטרוניקה פיזיקאלית - טלי דותן

22 במרץ 2017, 10:00

אוניברסיטת תל אביב בית ספר להנדסת חשמל ביניין וולפסון חדר 234

סמינר מחלקתי - אלקטרוניקה פיזיקאלית - טלי דותן

You are invited to attend a lecture

Precursor effects on Self-Assembled Monolayer (SAM) Cu Barrier Properties

for Sub-22 nm CMOS

By:
Tali Dotan

M.Sc student under supervision of Prof. Yosi Shacham-Diamand

Abstract
The purpose of this work was to study various Self Assembled Monolayers (SAM) as barrier layers in microelectronics. Recent reports have shown that organic Self Assembled monolayer (SAM) can be used as barrier layers against Cu diffusion for VLSI interconnect applications. In our work silanization was performed by chemical method from solutions, containing 1-2% silane in ethanol as a solvent. 7 different silanes were used and their barrier properties were measured using a "sandwich" Cu (100 nm)/SAM/Si structure. The barrier effectiveness was tested by vacuum annealing at the 200-500˚C range for periods up to 12 hours. Results reveal that N-[3-(Trimethoxysilyl)propyl]aniline and M-Aminophenyl-trimethoxysilane of the thickness of ~ 2 nm are the most effective and suitable barriers. They both have a head group of trimethoxy. One has a phenyl terminal group acting as a bulky barrier and the other an amino group that most likely forms Cu-N complex. XPS analysis is used to characterize the failure mechanism of the diffusion barriers and to validate the formation of copper silicide in the Cu/Si interface. Our results suggest that SAMs with appropriate terminal groups could be used to as barrier layer for in advanced ULSI interconnect technology. The method discussed in our work, using Cu/SAM/Si as a test structure is assumed to be predictive for the SAM effectiveness for Cu low-K metallization; however, this should be further tested.

On Wednesday, March 22, 2017, 10:00
Room 234, Wolfson building

סמינר מחלקתי ביה"ס להנדסה מכאנית Roee Finkelshtain and Slava Burkin

05 באפריל 2017, 14:00

וולפסון 206

סמינר מחלקתי ביה"ס להנדסה מכאנית Roee Finkelshtain and Slava Burkin

School of Mechanical Engineering Seminar
Thursday, April 5, 2017 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Application of diffusive interface method to thermocapillary - driven flow of two immiscible fluids.

Viacheslav Burkin

M.Sc. Student of Prof. Alexander Gelfgat

A diffusive interface method was used to solve a problem of flow of two immiscible fluids driven by a thermocapillary force in a closed rectangular cavity. The traditional approach to this problem considers boundary conditions along the interface between two fluids, similar to those applied at physical boundaries of the volume: continuity of the viscous stresses and the heat flux.

Since boundaries between two liquids are usually curved, an accurate calculation of normal and tangent derivatives, needed for a straight-forward implementation of the boundary conditions, becomes a very complicated task. An alternative approach, that noticeably simplifies numerical model, is the volumetric approximation of the thermocapillary force. This approach assumes that fluids properties across the liquid-liquid interface change as a smoothed Heaviside function, while thermocapillary force is defined by a smeared delta-function. In current work we provide further enhancement of this method, by comparing different Heaviside functions by their accuracy relative to the known analytical solution, and adopt this method for computation of steady flow and analysis of their stability.

School of Mechanical Engineering Seminar
Wednesday, April 5, 2017 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Ultrasonic yield assessment

Roee Finkelshtain

G. Kósa¹, Y. Yovel², A. Bechar³

Israel

¹School of Mechanical Engineering, Tel Aviv University (TAU), Israel

²Faculty of Life Sciences, TAU, Israel

³Institute of Agricultural Engineering, Agricultural Research Organization (ARO),

The spectrum of an ultrasonic return echo from plants has shown to contain information about them. This research focuses on developing an ultrasonic robotic sensing system, analyzing the ultrasonic classification features that would ultimately be used as the basis for a yield estimation robotic system, and developing an algorithm for prediction of fruit mass per plant based on the ultrasonic echoes returned from a plant. The ultrasonic sensor system was tested in a lab and pepper greenhouse environments and on single pepper plants, single leaves and fruit. The ultrasonic sensor system was integrated to a robotic platform and field experiments were conducted in a research pepper greenhouse. The results showed the potential of ultrasonic sensors for such a robot in classifying plants and greenhouse infrastructures, the ability to detect hidden plant rows and fruits as well as making an estimation of the fruit mass in single plants. A developed multi linear regression model for estimating the energy level was found to be highly significant with of and for to and to ranges respectively. The estimation accuracy is improved by mounting the sensing system on a monitoring robot and acquiring large plant-orientation sampling sets.

EE Seminar: Modeling and Learning Similarity of Shapes, Images and Signals

Speaker: Roee Litman

Ph.D. student under the supervision of Prof. Alex Bronstein

Monday, March 27^th, 2017 at 15:00
Room 011, Kitot Bldg., Faculty of Engineering

Modeling and Learning Similarity of Shapes, Images and Signals

Abstract

More than a decade ago, a major part of computer vision research was dedicated to engineering and designing the best way to capture meaningful features in images. So was the case in geometry processing and shape analysis. With time, the size of annotated datasets grew, also becoming more realistic and challenging. Together with the increase of low-cost computational power, this turned the focus of research more and more towards learning those features from the data themselves. While problem modeling is still a crucial part of research, learning-based methods are particularly successful whenever noise-invariance is harder to model, especially when the data are deviating from theory.

I will present several new methods and advances for the problem of measuring similarity and establishing correspondence between shapes, images and signals. The topics covered here progress from `designed' to `learned' in a gradual manner. First, there are some cases where the `right' model can solve the problem in a manner close to optimal, as shown for the problem of shape correspondence. Next, a model can be designed such that some small parts are allowed to adjust according to examples in order to improve performance, as shown in the case of shape descriptors. Finally, in some cases the model makes very mild assumptions and is almost completely learned from examples, as in the case of task specific sparse models.

27 במרץ 2017, 15:00

חדר 011, בניין כיתות-חשמל

Biomedical seminar

26 במרץ 2017, 14:30

מרב קטלוניה

תלמידת המחלקה להנדסה ביו רפואית לתואר שלישי תרצה בנושא:

Effect of Peripheral Electrical Stimulations on Glycemic Control Loop in Diabetes Patients

The epidemic nature of type 2 diabetes mellitus (T2DM), along with the downsides of current treatments, has raised the need for therapeutic alternatives. In this research we evaluated the effect of noninvasive peripheral electrical stimulation (PES) on glucose regulation in preclinical, and clinical pilot studies.

In a preclinical model, we studied normo-glycemic and high-fat diet (HFD), induced insulin-resistant rats for 3 weeks. In addition, the effect of an acute PES treatment on metabolic rates of glucose appearance and turnover was measured by using the hyperinsulinemic–euglycemic clamp test. This study demonstrates that a noninvasive PES treatment of very short duration in rats is sufficiently potent to stimulate glucose utilization, improve hepatic insulin sensitivity, and have a beneficial effect on body weight.

Then, a clinical study was designed to evaluate safety, tolerability, and the glucose-lowering effect of PES treatment in T2DM patients. Twelve patients were recruited for an open label, interventional, randomized trial, and underwent, in a crossover design, an active, and a no-intervention control trial periods. During the active period, the patients received a daily lower extremity PES treatment for 14 days. Endpoints were analyzed based on continuous glucose meter readings, and laboratory evaluation. The study results indicate that repeated PES treatment may suppress hepatic glucose production, and thus, act to maintain basal overnight and fasting glucose concentrations. This effect may be mediated, at least in part, by hypothalamic-pituitary-adrenal axis modulation.

Using mathematical model analysis of systemic glycemic control during nocturnal sleep, we explored possible neuroendocrine mechanisms involved in this therapeutic strategy.

Future studies, including larger populations, and longer follow up periods, are needed to gain better understating of these methods. Once proven over a larger cohort of patients, PES may provide an additional potential treatment strategy for the current solutions available for T2DM patients.

העבודה נעשתה בהנחיית ד"ר אורי נבו מהמחלקה להנדסה ביו-רפואית,

ופרופ' אשל בן-יעקב ז"ל מביה"ס לפיסיקה ואסטרונומיה, אוניברסיטת תל אביב

ההרצאה תתקיים ביום ראשון 26.03.17, בשעה 14:30

בחדר 315, הבניין הרב תחומי, אוניברסיטת תל אביב

Ultrasonic yield assessment

עמודים