Sometimes, one darn thing leads to another in a series of cascading failures. Understanding the weak points that lead to such cascades could help us make better investments in preventing them.
Professor Raissa D’Souza in the UC Davis College of Engineering studies complex systems and how they can go wrong.
In the Nov. 17 issue of Science, Raissa D’Souza, professor of computer science and mechanical and aerospace engineering at UC Davis, wrote a perspective article about cascading failures that arise from the reorganization of flows on a network, such as in electric power grids, supply chains and transportation networks.
To win the battle against heart disease, cardiologists need better ways to identify the composition of plaque most likely to rupture and cause a heart attack. Angiography allows them to examine blood vessels for constricted regions by injecting them with a contrast agent before X-raying them. But because plaque does not always result in constricted vessels, angiography can miss dangerous buildups of plaque. Intravascular ultrasound can penetrate the buildup to identify depth, but lacks the ability to identify some of the finer details about risk of plaque rupture.
Creating a model of atrial fibrillation with live human heart cells on a chip is the goal of a new $6 million, five-year grant to Professor Steven George at the UC Davis Department of Biomedical Engineering and colleagues at Washington University in St. Louis.
UC Davis biomedical engineer Steven George will grow heart cells on a chip to study atrial fibrillation.
Atrial fibrillation is an irregular heartbeat caused when the heart’s upper chambers beat chaotically and out of sync with the lower chambers, leading to a variety of health problems including stroke and death. Nearly one in ten people over the age of 65 suffer from atrial fibrillation at a cost of around $6 billion.
For most of us Monday’s solar eclipse was a wonderful spectacle, but some scientists were out gathering data, too. Holly Oldroyd, assistant professor in the UC Davis Department of Civil and Environmental Engineering, joined a team led by Chad Higgins at Oregon State University to measure atmospheric fluxes during the eclipse.
As night turns to day and back there are changes in atmospheric temperature and pressure, water vapor and carbon dioxide, and in emissions from soils and plants into the atmosphere. Higgins’ experiment aimed to find out whether the same kinds of changes take place during the very short “night” created by the total solar eclipse. Normally these measurements are taken over time spans of half an hour or so, so the team, which also included researchers at Lawrence Livermore National Laboratory, had to come up with ways to make accurate measurements over a couple of minutes.
The Research Center of the Specialty Coffee Association (SCA) is teaming up with the UC Davis Coffee Center to embark on a two-year project to re-evaluate the scientific assumptions, measurement tools, sensory information, and – most importantly – consumer research that forms the foundation of the coffee industry’s fundamental understanding of coffee brewing.
Students in the UC Davis “Design of Coffee” class learn engineering principles from roasting and brewing coffee.
This research is underwritten with funding from Breville, which produces high-end appliances, including coffee and tea equipment.
On January 20, 1990, when the nuclear reactor at McClellan Air Force Base achieved its first sustained nuclear reaction known as “criticality,” it was the newest reactor in the United States.
Six years later, when the Tennessee Valley Authority launched the Watts Bar Nuclear Generating Station, the nuclear reactor at McClellan was relegated to second newest. McClellan would go on to retain that ranking for another two decades until this past October when the Tennessee Valley Authority launched Watts Bar Unit 2.
The UC Davis-based EXPLORER consortium, which aims to build a revolutionary total-body PET (positron emission tomography) scanner, has announced the selection of two industry partners to help build the prototype device. They are United Imaging Healthcare America, a North American subsidiary of Shanghai United Imaging Healthcare, and SensL Technologies of Cork, Ireland.
Positron emission tomography, or PET, scanning uses short-lived radioactive tracers to show how organs and tissues are functioning in the body, while magnetic resonance imaging (MRI) and computed tomography (CT) scans mostly show anatomy. PET scans are widely used to diagnose and track a variety of illnesses, including cancer, heart disease and Alzheimer’s disease.
Solar cells made from perovskites have sparked great excitement in recent years because the crystalline compounds boast low production costs and high energy efficiencies. Now UC Davis scientists have found that some promising compounds — the hybrid lead halide perovskites — are chemically unstable and may be unsuited for solar cells.
“We have proven these materials are highly unlikely to function on your rooftop for years,” said Alexandra Navrotsky, interdisciplinary professor of ceramic, earth, and environmental materials chemistry at UC Davis and director of the Nanomaterials in the Environment, Agriculture, and Technology (NEAT) organized research unit.
Our electronic devices are based on what happens when different materials are layered together: “The interface is the device,” as Nobel laureate Herbert Kroemer famously claimed over 40 years ago. Right now, our microchips and memory devices are based on the movement of electrons across and near interfaces, usually of silicon, but with limitations of conventional electronics become apparent, researchers are looking at new ways to store or process information. These “heterostructures” can also find applications in advanced batteries and fuel cells.
Now physicists at UC Davis have observed what’s going on at some of these interfaces as oxygen ions react with different metals, causing drastic changes in magnetic and electronic properties.
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How many projects can you work on at the same time, before losing efficiency? There are many reasons to get involved in multiple projects – impress your boss, gain personal satisfaction, help out colleagues or just because you’re interested. But at some point, there must be one project too many.
“There is a limit,” said Bogdan Vasilescu, postdoctoral researcher in the DECAL lab at the UC Davis Department of Computer Science. “Multitasking fills time that’s otherwise unused, but there is a limit at four or five projects in a week.”