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Faculty of Engineering and Architecture


    Spotlight on Recent Journal Articles

    Better mixing with Bubbles (July 2017)

    Who has not chased a bubble rising in the air, or blown into a straw to create a mound of bubble foam in milk or water? Probably few realized that bubbles both move and cause movement, and that they can be used to mix things together by increasing the area of contact?

    Prof. Fuad Azizi, a chemical engineer in the Maroun Semaan Faculty of Engineering and Architecture, along with graduate student
    Khaled Abou Hweij, are putting bubbles to work. In a recent article in the Journal of the American Institute of Chemical Engineers
    (2017 Vol. 63, No. 4) they describe varying the size of openings in a screen that is used to generate bubbles from gases exiting a submerged tube, allowing the gases to mix more quickly and completely with the surrounding liquids.  Their research led to the design
    of a screen-type static mixer in which the substances being mixed spend the longest time in a bubble phase. These novel mixers allow equipment in chemical processing facilities to be as much as 1000 times smaller.

    An important application of static mixers is for removing contaminants or pollutants from gas streams, such as removing Sulphur from natural gas, which leaves us with cleaner burning fuels, or to capture or dissolve CO2 in water, which would make desalinated sea water taste better. Prof. Azizi said that what he finds most exciting is that “we are breaking records. We are achieving high process
    rates with low energy requirements and this kind of process intensification is good for the environment."

    New research uses social media photographs and annotations for rapid emergency response in natural disasters
 (July 2017)

    It is estimated that almost 400 natural disasters occur each year, causing hundreds of thousands of casualties and material damage valued at more than 150 billion dollars. With more than 3 billion people online, it is no surprise that images from disaster scenes end up posted in social media venues like Facebook, often as the devastation is unfolding. Professor Mariette Awad and her research team in the Maroun Semaan Faculty of Engineering and Architecture at the American University of Beirut wondered whether these images could be useful to first responders. 

    At the 12th International Conference on Signal-Image Technology and Internet-Based Systems in Naples, Italy, Awad and her students Hadi S. Jomaa and Yara Rizk, reported a new automated approach for humanitarian computing to mine online images and the words people attach to them in order to rapidly identify disasters and classify them by type.  The system is in its early stages of development but it has so far proven to be more than 95% accurate in its ability to categorize damage.

    To create the system, the AUB researchers uploaded images gathered online and divided them into two broad categories of damage: infrastructure and nature. Colors, shape, texture, and feature combinations help the system to identify the image category. They then developed two “bags of words” to describe the images in each category. Focusing on high frequency words allowed them to manage the range of language possible. Professor Awad explained that “this system can grow and learn.” Professor Awad hopes that humanitarian computing can be used to prioritize first responders and save lives in war zones as well as natural disaster sites.  

    AUB researchers revive ancient technique wth a twist (May 2017)

    Have you ever wondered why some buildings have cooling breezes even on the hottest days? Or, how people managed to live comfortably in this region before there was electricity for fans and air-conditioning. Our desire for windows in our homes and workspaces has created some of the problems we currently face in achieving comfortable indoor living conditions. However, few of us would choose to live in a dark, damp, albeit cool cave.

    We all want windows with views in our homes and workspaces. Looking off into the distance helps us to relax. Wouldn’t it be nice therefore not to have to close blinds to keep the sun from heating up the room? Thermal pane windows help with some of the heat generated by the sun but we still end up having to close the blinds and block our windows for parts of the day. Thermal pane windows are two or more pieces of glass that are sealed together with airspace between them.
    In the March 2017 issue of Energy and Buildings journal, a team of mechanical engineering at AUB has come up with an innovative idea. Profs. Nisreen Ghadar and Kamel Ghali, working with graduate students Walid Abou Hwejj and Albert Al Touma, tested an open system where air could flow between the layers of glass.

    Combining the ancient knowledge that hot air rises and water evaporation helps to lower temperatures with an understanding of Computational Fluid Dynamics (CFD) the FEA team has proposed a new model for a window design. The design was tested in the hot dry climate of Riyadh. As the sun heats the side of the building, the proposed design allows the building to respond to the change in climate by giving the hot air a narrow opening above the window to rise through; essentially, creating a thermal chimney. This movement of air draws the hot air from below the window in a continuous flow past a reservoir of water, through an open space between two pieces of glass thereby cooling the glass and lowering the amount of heat transferred through the glass into the room. This improves the thermal comfort of the room for its occupants and has the potential to reduce energy consumption by 10%. Cooling the external surface of a window would allow you to keep the shutters open, let the light in, and continue to enjoy the view. We need new technologies that will help us to keep cool said Dr. Ghali. The Gulf and MENA regions will be hit hard by the effects of global warming.

    AUB researchers use the power of the sun to neutralize drugs in drinking water (May 2017)

    When we think of water pollution we often think of the run off from large chemical companies, massive oil spills, or perhaps the presence
    of bacteria that will make us ill. However, the drugs we each take to relieve every day aches and pains are finding their way into the water supply and into our drinking water in ever-greater concentrations. When we take a pill not all the drug is absorbed into our body; some passes through us and is flushed down the toilet. Without thinking many of us also dispose of unused medicines by washing them down
    the drain. Trace pharmaceuticals are now found throughout the world in surface water, ground water, and in our coastal seawater.

    The need to improve our understanding, behavior, and the processes required to purify our water for drinking has never been more urgent. In a recent article appearing in Science of The Total Environment journal, a team of researchers at AUB: Dr. George Ayoub, a civil
    engineer; Dr. Mahmoud Al-Hindi, a chemical engineer; Dr. Antoine Ghauch, a chemist; and Abbas Baalbaki a graduate student in the environmental technology program, report their findings on the fate of five common chemically distinct pharmaceuticals that might be present in the water that you think of as clean. Because most pharmaceuticals are designed to be thermally stable and they are known
    to be light sensitive, experiments to discern the effects of light, heat, and the combined effect of light and heat on each of the drugs were under taken.

    Ibuprofen, diclofenac, carbamazepine, ampicillin, and naproxen were carefully studied as they passed through the distillation process of a low cost solar still. The experiments were set up on the roof of the CCC-scientific research building at AUB.
    Three environment factors were monitored throughout this study, namely, temperature, solar radiation intensity, and ultraviolet radiation intensity.

    The results indicated that solar stills are highly effective in removing several of the pharmaceuticals. Three of the pharmaceuticals tested, (ibuprofen, carbamazepine, and naproxen) required the effect of light and temperature combined to degrade significantly. But the results
    are not simple… some of the byproducts, after exposure to direct sunlight, were transferred to the distilled water. Naproxen resulted in an array of up to ten different unidentified byproducts some of which may be more toxic than their parent compound.

    There is obviously more work to be done to ensure that we have clean, safe drinking water. Working together AUB chemical engineers, chemists, and civil engineers are doing the vital research required to meet the growing challenges of modern life.

    AUB Research uncovers hidden danger in e-cigarette flavors (November 2016)

    A recent laboratory study at the American University of Beirut (AUB) has shown some additives used to flavor the liquids for electronic cigarette becomeblished in the peer review journal Tobacco Control authored by members of the Center for the Study of Tobaccblished in the peer review journal Tobacco Control authored by members of the Center for the Study of Tobacco Products (CSTP) at AUB, including masters' student Sarah Soussy who wrote her thesis on the subject, under supervision of
    Dr. Najat Saliba, associate professor in analytical chemistry.


    Sou ssy explained that manufacturers often claim the flavor-enhancing additives in e-cigarette liquids are safe because they are commonly used in food production. "However, this argument is misleading because food additives are meant for ingestion, not inhalation, and because they can be transformed chemically in the heated element of the electronic cigarette," she said.  

    For example, saccharides, used to impart a sweet flavor, decompose into furan compounds-which are toxic-in e-cigarettes. 

    The use of such additives has been widely banned in conventional cigarettes, but their presence is a characteristic of the countless different flavors of e-cigarette liquids. Just as with the inclusion of fruit and candy flavors in water-pipe tobacco, the flavors are controversial as it is feared they encourage non-smokers to use them, especially children. 

    The AUB study found that furan compounds were positively correlated with the concentration of the sweeteners in the liquid and the electrical power of the electronic cigarette. 

    Per-puff levels of furan compounds in electronic cigarettes were found to be comparable to those in conventional cigarettes. 

    CSTP's work is part of an ongoing series of studies at AUB funded by the US Food and Drug Administration and National Institutes of Health and conducted under the leadership of the Dean of the Faculty of Engineering and Architecture Professor Alan Shihadeh and Professor Najat Saliba. 

    The use of Membrane Biotechnology to treat leachate in landfills (September 2016)

    Landfills remain an important element of most solid waste management schemes around the world, even in areas with good recycling, reuse, and reduction practices. A byproduct of landfills is a toxic liquid known as leachate that often penetrates into the underground water sources. This problem is particularly acute when the landfill waste contains a high percentage of food waste as is the case in Lebanon. 

    In his September 2016 published article entitled “Membrane bioreactor technology for leachate treatment at solid waste landfills” Professor Mutasem El-Fadel and his team are studying the use of membrane bioreactors to treat leachate at solid waste landfills. Their approach consists of putting solid waste into a box known as a reactor that allows leachate generation in a short amount of time which later moved into a membrane that traps harmful materials.

    El Fadel said that “MBR technology offers several advantages over conventional systems such as reduced foot print, high effluent quality, replacement of post-digestion settlement and clarification, less sludge production, and ease of retrofitting to existing works” El Fadel and his team performed a bench top lab experiment using a comparative assessment of MBRs equipped with the most common membranes in the market today “Hollow Fiber” vs “Flat Sheet” which demonstrated that MBR technology can treat leachate effectively.

    MBR technology has shown promising results in treating landfill leachate and the scale up of this approach can reduce the environmental footprint in Lebanon and beyond.

    3D Concrete Printing: A New building method for more affordable homes (June 2015)

    As construction costs have been on the rise, housing has become unaffordable for many families. 3D concrete printing is a promising new technique that could revolutionize the construction industries, and make housing more affordable. This possibility has kept a team of AUB researchers in the CEE department busy for the past months as they developed a home-built 3D concrete printing. A 3D concrete printer builds a structure by extruding and depositing concrete layer by layer.

    In a recent study published in the International Journal of Civil Engineering & Technology, the team led by Prof Farook Hamzeh, investigated optimal materials for use with this technique, looking at such variables as the structural integrity of the printed products. Hamzeh said that “Such a technique can easily be used in developing countries, which are in need of a suitable, low-cost and fast building construction method.”

    He explained that further research will focus on optimizing machine operation, adjusting the concrete mix for different products, and developing several methods to reinforce the printed products for structural integrity. He also pointed out, scaling up the 3D printing operation may play an important role in post-disaster reconstruction, and may even be used to recycle concrete from destroyed dwellings in war torn areas​
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