152 research outputs found
Lagrangian computations of radiating fire plumes
No full textThesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.Includes bibliographical references (leaves 209-217).by Issam Adnan Lakkis.Ph.D
Grid-Free Vortex Methods for Natural Convection in Two-Dimensional Domains
No full textVortex methods for simulating natural convection of an ideal gas in unbounded two-dimensional domains are presented. In particular, the redistribution method for diffusion is extended to enable simulation of nonlinear diffusion of an ideal gas in isobaric conditions encountered in unbounded low-Mach number flows. We also address the problem of handling source terms in grid-free vortex methods and propose a fast, accurate, and physically motivated method for solving the associated inverse problems. Examples include generation of baroclinic vorticity in nonreacting buoyancy driven flows, and in addition, generation of internal energy and species in buoyant reacting flows. Accuracy and speed of the proposed algorithms for nonlinear diffusion and vorticity generation are investigated separately. Simulations of natural convection of a thermal patch for Grashof number ranging from to 1562.5 to 25000 are presented. Copyright © 2012 by ASME
Eddy Detection Using Reanalysis Datasets
No full textOceanic eddies are ubiquitous in oceans and play a major role in several parameters that include ocean energy transfer, nutrients distribution and air-sea interaction. Typically, eddy detection algorithms are based on single physical parameter, geometrics or other handcrafted features. To achieve better performances, we aim to develop a new approach to fuse multi-variable features for eddy detection. We will investigate lumping satellite datasets of Sea surface height, Sea surface temperature, Salinity in addition to full model solution velocity field through the inclusion of information (correlation) between the datasets
Stochastic Transport and Identification of Moving Passive Tracer Sources with Application to Marine Traffic in the Mediterranean Sea
No full textThesis. M.E. American University of Beirut. Department of Mechanical Engineering, 2020.
Advisor : Prof. Issam Lakkis, Professor, Mechanical Engineering ; Committee members : Prof. Omar Knio, Professor, King Abdullah University of Science and Technology ; Prof. Ibrahim Hoteit, Professor, King Abdullah University of Science and Technology ; Prof. Fadl Moukalled, Professor, American University of BeirutSource Reconstruction Problems are widely used for the aim of determining the sources of contaminants and pollutants in the case of deliberate or accidental release scenarios. This involves the inverse problem and inference of the sources parameters given a set of observed and measured data for direct emergency actions and services while estimating at the same time the nature of the threat in order to avoid and manage escalating consequences.
The aim of this thesis report is to introduce the methodology and results of the inference and source reconstruction problems with an application to contaminants and pollutants transport in the Mediterranean Sea in the presence of a stochastic velocity field. This will allow immediate and accurate actions in emergency cases such as any unexpected release scenario.
The forward Lagrangian model, adopted in transporting the pollutants, is first introduced followed by a detailed discussion of the full implementation of the stochastic transport of moving passive tracers in the Mediterranean Sea in the presence of a stochastic velocity field. This also involves building the probability maps for various release scenarios along a given ship path.
In addition, a new sampling based approach, similar to MCMC algorithms and based on the evaluation of the cost function between the modelled likelihood of the contributing events and the observation patch, is introduced. This algorithm allows the inference of single and multiple sources in the Mediterranean Sea with a quantitative measure of the relative contribution of these sources to the observation patch while quantifying the uncertainty in the solution. The results obtained from this proposed inference algorithm are illustrated and are in accordance with the true solution obtained using a deterministic optimization approach
Development of a Smart Algorithm for Air Pollution Sources Identification using Physical Dispersion Modeling and Bayesian Inference
No full textIssam Lakkis; Dany Abou Jaoude; Ibrahim HoteitAir pollution plumes are commonly observed in the atmosphere above many cities and residential areas. These plumes may be the result of either a normal operation or an accidental release from certain sources. In both cases, it is of great importance to identify and characterize these sources for the assessment of the harmful effects of their resulting pollution fields and for the proper construction of an emergency response plan in case of accidental releases. This involves the inverse problem, from destination of pollution back to its source, and the inference of the different parameters characterizing this source given certain known or measured sets of observations. The aim of this thesis work is to introduce and develop a smart algorithm that is able to identify and characterize an air pollution source that is responsible for an observed concentration field of pollutants in a specific urban location. As an application, we will infer several parameters of an active source that is releasing air contaminants into the atmosphere of a selected domain around KAUST (King Abdullah University for Science and Technology) in the region of Thuwal, KSA. These parameters include the source geographic location, emission strength and emission duration. A stochastic approach using Bayesian inference and Monte Carlo sampling will be implemented to solve the ill-posed inverse problem and characterize the emitting source. In this scope, the forward Lagrangian model will be adopted to study the atmospheric dispersion of pollutants and resolve the urban characteristics of the domain. The implementation of this model will be done while considering the prevailing wind field as the main driving source and based on the well-known urban configuration of buildings and the natural topographic features of the locatio
Reduced-order modeling of low mach number unsteady microchannel flows
No full textWe present reduced-order models of unsteady low-Mach-number ideal gas flows in two-dimensional rectangular microchannels subject to first-order slip-boundary conditions. The pressure and density are related by a polytropic process, allowing for isothermal or isentropic flow assumptions. The Navier-Stokes equations are simplified using low-Mach-number expansions of the pressure and velocity fields. Up to first order, this approximation results in a system that is subject to no-slip condition at the solid boundary. The second-order system satisfies the slip-boundary conditions. The resulting equations and the subsequent pressure-flow-rate relationships enable modeling the flow using analog circuit components. The accuracy of the proposed models is investigated for steady and unsteady flows in a two-dimensional channel for different values of Mach and Knudsen numbers. Copyright © 2014 by ASME
System level modeling of microfluidic devices - by Balsam Assem Nehme
No full textThesis (M.E.)--American University of Beirut, Dept. of Mechanical Engineering, 2007.;"Advisor:Dr. Issam Lakkis, Assistant Professor, Mechanical Engineering--Member of Committee: Dr. Nesreen Ghaddar, Professor, Mechanical Engineering--Member of Committee:Bibliography: leaves 76-79.An innovative Polymerase Chain Reaction (PCR) prototype based on improved behavi oral models of a particular set of components is developed for ameliorating the efficiency, running time and cost of a device that carries out DNA amplification in the micro
Effect of ventilation periodicity on carbon monoxide formation in a transient forward smoldering char bed - by Elie Micheal Kfoury
No full textThesis (M.E.)--American University of Beirut, Dept. of Mechanical Engineering, 2009.;"Advisor: Dr. Alan Shihadeh, Associate Professor, Mechanical Engineering Dept.--Co-advisor : Dr. Issam Lakkis, Assistant Professor,Mechanical Engineering Dept.--Member ofBibliography : leaves 91-95.Laboratory measurements of smoked tobacco products are routinely performed to co mpare toxicant and carcinogen yields across products and to provide information on potential health hazards arising from the use of these products. Standard ci garette smok
The unsteady dynamics of a jet impinging on a moving plate - by Naima Hammoud
No full textThesis (M.S.)--American University of Beirut, Dept. of Physics, 2010.;"Co -Advisor : Dr. Jihad Touma Associate Professor ,Physics--Co - Advisor : Dr. Issam Lakkis Assistant Professor ,Mechanical Engineering--Member of Committee : Dr. Leonid Klushin ProBibliography : leaves 80-81.The unsteady dynamics of a low Reynolds number jet impinging on a moving flat plate will be investigated. The objective is to present a physical explanation of the dynamics of low-frequency jet oscillations observed in industrial applications and to comp
MDOCS Poster-2018-02-06, Issam Nassar
No full textFebruary 6, 6pm
Location: Payne Room
Free and open to the public.
In conjunction with the exhibition This Place
Part of the Palestinian Voices series, organized and co-sponsored by the John B. Moore Documentary Studies Collaborative (MDOCS), the Environmental Studies and Sciences Program, International Affairs, Media and Film Studies, Art History, History, Hayat, and the Skidmore College Dean’s Office
Join us for a lecture by Issam Nassar on the history of Palestinian photography. Nassar is a historian of the Modern Middle East and of Photography at Illinois State University. His work focuses on the modern Middle East and the history of photography. He is the co-editor of Jerusalem Quarterly and the author and editor of a number of books, including the editor of I Would Have Smiled: Photographing the Palestinian Refugee Experience (Institute for Palestinian Studies, 2009) with Rashā Salṭī, and The Story of Jerusalem (Olive Branch Press, 2013).
Murat Yildiz, Assistant Professor of History at Skidmore College, will introduce Nassar and moderate a discussion following the talk.
This talk is part of exhibition This Place, on view February 3 through April 22, 2018, as well the Palestinian Voices series. The Palestinian Voices series is organized and co-sponsored by the John B. Moore Documentary Studies Collaborative (MDOCS), the Environmental Studies and Sciences Program, International Affairs, Media and Film Studies, Art History, History, Hayat, and the Skidmore College Dean’s Office.
This event is free and open to the public
- …
