The Department celebrates Class of 2019 and outstanding members of community at CEE awards banquet

May 17th, 20192019 News in Brief

On May 17, 2019 the Department gathered for the annual CEE awards banquet to celebrate the class of 2019 and their senior capstone presentations, and to applaud the CEE award recipients. Awards were given to the best capstone posters and to notable members of the community who have significantly contributed to the CEE mission. The winners for the best capstone poster presentations were Apisada (Ju) Chulakadabba who received first-place, Tim Roberts who was runner-up, and David Wu who earned third-place. View the full list of the award recipients here.  

On May 17, 2019 the Department gathered for the annual CEE awards banquet to celebrate the class of 2019 and their senior capstone presentations, and to applaud the CEE award recipients. Awards were given to the best capstone posters and to notable members of the community who have significantly contributed to the CEE mission. The winners for the best capstone poster presentations were Apisada (Ju) Chulakadabba who received first-place, Tim Roberts who was runner-up, and David Wu who earned third-place. View the full list of the award recipients here.

 

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Mechanics of Materials: The Final Project; or, A for Effort

May 16th, 2019Mechanics of Materials

By Rayna Higuchi '20 Hi CEE! I’m Rayna, a student in the Mechanics and Materials track, blogging about my experiences in Course 1. Today, I’ll be talking about the class Mechanics of Materials (1.035), taught by Professor Ulm, with additional instructors Stephen Rudolph and Omar Al-Dajani. The semester’s wrapping up, and we all know what that means: Final projects!!! In 1.035, that means designing and testing our own concrete. The goal of this project was to design a more sustainable cement. A commonly cited fact among civil engineers is that concrete is responsible for producing more than 8% of the global carbon dioxide emissions! In 2016, this was around 2.2 billion tons. To put that into context, if concrete were a country, it would be the third-biggest contributor of CO2in the world, behind China and the U.S.! But what’s really interesting to look at is why this is the case. When compared to other construction materials such as steel, the carbon output for a kilogram of concrete is very low. Yet, concrete has a much higher global total CO2 output simply because it is so ubiquitous. Concrete is everywhere. And while we can’t ask countries to stop developing their infrastructures, or people to stop building homes, we can reduce the carbon footprint of concrete in other ways. Even a small reduction in the embodied carbon of concrete could reduce CO2 emissions on a global scale. So, while it is important to focus on all forms of greenhouse gas emissions, the question is: how [...]

By Rayna Higuchi ’20

Hi CEE! I’m Rayna, a student in the Mechanics and Materials track, blogging about my experiences in Course 1. Today, I’ll be talking about the class Mechanics of Materials (1.035), taught by Professor Ulm, with additional instructors Stephen Rudolph and Omar Al-Dajani.

The semester’s wrapping up, and we all know what that means: Final projects!!! In 1.035, that means designing and testing our own concrete.

The goal of this project was to design a more sustainable cement. A commonly cited fact among civil engineers is that concrete is responsible for producing more than 8% of the global carbon dioxide emissions! In 2016, this was around 2.2 billion tons. To put that into context, if concrete were a country, it would be the third-biggest contributor of CO2in the world, behind China and the U.S.!

But what’s really interesting to look at is why this is the case. When compared to other construction materials such as steel, the carbon output for a kilogram of concrete is very low. Yet, concrete has a much higher global total COoutput simply because it is so ubiquitous. Concrete is everywhere. And while we can’t ask countries to stop developing their infrastructures, or people to stop building homes, we can reduce the carbon footprint of concrete in other ways. Even a small reduction in the embodied carbon of concrete could reduce COemissions on a global scale. So, while it is important to focus on all forms of greenhouse gas emissions, the question is: how can we make concrete more sustainable?

My group focused on two potential methods. First, carbon sequestration. If you take an organic waste product such as pulp from a paper mill or agricultural waste and burn it in a low-oxygen environment, it undergoes a reaction called pyrolysis. This is the reaction that forms charcoal. Pyrolysis traps most of the carbon in a stable solid form. We thought that this solid, biochar, could be mixed into our concrete to sequester the carbon.

Biochar! We made this by burning wood shavings in an oven with a cover on. Claire Holley (’20)

Mixing the cement. Photo courtesy of Stephen Rudolph.

Secondly, we looked at reducing the total amount of cement used per liter of concrete. Bringing this number down by all or partial replacement would lower the embodied carbon of concrete drastically. We sought to replace 40% of our cement with other supplementary materials, which on their own cannot undergo the reaction that hardens the concrete but can do so when in the presence of cement and water. Individually, either of these ideas might have fared well. But together, what resulted was a concrete that crumbled quickly under pressure (honestly, same).

In comedy, there exists the phrase “a hat on a hat”. This is when you take two distinct and individually funny concepts and try to put them in the same sketch, either both at once, or one right after the other. Rather than being even funnier, they detract from each other, and the sketch has less comedic value than it would using either piece alone. The solution is usually simple: pick one and go with it. Our experiment failed in part because we had so many interacting variables that we couldn’t begin to predict how they would all play out. We needed to pick a hat.

This experiment was unsuccessful, but it was interesting, and it taught us a great deal. The best way to learn is by doing, and I felt that this project helped us learn more about concrete than any homework assignment or textbook ever could. We didn’t save the world, nor even our grades, but I’m glad we tried something new.

CEE you next time!

Inside of sample 1 post-testing. The inside is darker than the outside because water is still present. This means we added too much water to react with the available binder (cement + additives), and what was left remained enclosed in pores, further weakening our concrete.

 

 

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Professor Heidi Nepf and Dr. Jiarui Lei, publish research on seagrass’ ability to curb erosion

May 3rd, 20192019 News in Brief

Donald and Martha Harleman Professor Heidi Nepf and recent PhD student Jiarui Lei published research in the Journal of Fluids and Structures titled “Blade dynamics in combined waves and current” and in Coastal Engineering, titled “Wave damping by flexible vegetation,” that demonstrates seagrass’ strong potential for curbing erosion. By dissipating wave energy, the plants could help protect vulnerable shorelines in the face of rising sea levels. Through experiments and mathematical modeling, the researchers were able to quantify how large and dense seagrass meadows must be in order to provide sufficient damping of waves in a given geographic, climate, and oceanographic setting. The abundant seagrass could help prevent beach erosion, protect seawalls, improve water quality, and absorb carbon. Read more on MIT News.   

Donald and Martha Harleman Professor Heidi Nepf and recent PhD student Jiarui Lei published research in the Journal of Fluids and Structures titled “Blade dynamics in combined waves and current” and in Coastal Engineering, titled “Wave damping by flexible vegetation,” that demonstrates seagrass’ strong potential for curbing erosion. By dissipating wave energy, the plants could help protect vulnerable shorelines in the face of rising sea levels. Through experiments and mathematical modeling, the researchers were able to quantify how large and dense seagrass meadows must be in order to provide sufficient damping of waves in a given geographic, climate, and oceanographic setting. The abundant seagrass could help prevent beach erosion, protect seawalls, improve water quality, and absorb carbon. Read more on MIT News.   

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Graduate student Audrey Bazerghi and PhD student Cherry Gao win first place in Patagonia Case Competition

May 3rd, 20192018 News in Brief

Graduate student Audrey Bazerghi and PhD student Cherry Gao won first place in the Patagonia Case Competition. Patagonia, the sustainable apparel company, organizes an international case competition each year in order to solve pressing challenges within environmental sustainability. This year, teams of graduate students were asked to propose sustainable packaging solutions that can be implemented at scale by 2025. 124 teams entered the competition and the top 10 finalists were invited to present in front of judges at the Berkeley Haas School of Business. Read more here.

Graduate student Audrey Bazerghi and PhD student Cherry Gao won first place in the Patagonia Case Competition. Patagonia, the sustainable apparel company, organizes an international case competition each year in order to solve pressing challenges within environmental sustainability. This year, teams of graduate students were asked to propose sustainable packaging solutions that can be implemented at scale by 2025. 124 teams entered the competition and the top 10 finalists were invited to present in front of judges at the Berkeley Haas School of Business. Read more here.

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Professor Eric J. Alm, Professor Tami Lieberman and graduate student Shijie Zhao publish research in Cell Host & Microbe

April 29th, 20192019 News in Brief

Professor Eric J. Alm, Herman L.F. Von Helmholtz Career Development Assistant Professor Tami Lieberman, and graduate student Shijie Zhao published research in Cell Host & Microbe titled “Adaptive Evolution within Gut Microbiomes of Healthy People.” The researchers combined culture-based population genomics with metagenomics to study the within-microbiome evolution of Bacteroides fragilis. The findings suggest that there is adaptive evolution within gut microbiomes of healthy people and point to genes important to long-term colonization. Read more here.

Professor Eric J. Alm, Herman L.F. Von Helmholtz Career Development Assistant Professor Tami Lieberman, and graduate student Shijie Zhao published research in Cell Host & Microbe titled “Adaptive Evolution within Gut Microbiomes of Healthy People.” The researchers combined culture-based population genomics with metagenomics to study the within-microbiome evolution of Bacteroides fragilis. The findings suggest that there is adaptive evolution within gut microbiomes of healthy people and point to genes important to long-term colonization. Read more here.

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Professor Otto X. Cordero, postdoctoral associates Julia Schwartzman and Manoshi Datta, and research affiliate Tim Enke discover simple assembly rules for polysaccharide-degrading marine microbiomes

April 29th, 20192018 News in Brief

Associate Professor Otto X. Cordero, postdoctoral associates Julia Schwartzman and Manoshi Datta, together with research affiliate Tim Enke discover simple assembly rules for polysaccharide-degrading marine microbiomes. The researchers showed that these microbiomes can be decomposed into functional modules, with each module encompassing bacterial species that degrade a specific type of polysaccharide, and an additional module containing species that consume simple metabolic byproducts released by the specialist degraders. These guidelines can help researchers understand the diversity of microbes in the environment, predict community composition, and rationally design ecological systems in the lab. Read more on MIT News.

Associate Professor Otto X. Cordero, postdoctoral associates Julia Schwartzman and Manoshi Datta, together with research affiliate Tim Enke discover simple assembly rules for polysaccharide-degrading marine microbiomes. The researchers showed that these microbiomes can be decomposed into functional modules, with each module encompassing bacterial species that degrade a specific type of polysaccharide, and an additional module containing species that consume simple metabolic byproducts released by the specialist degraders. These guidelines can help researchers understand the diversity of microbes in the environment, predict community composition, and rationally design ecological systems in the lab. Read more on MIT News.

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