Tyler O'Neal, Staff Editor ECONOMICS

Pitt civil engineers examine urban cooling strategies using reflective surfaces

If you've ever been in a city's central core in the middle of summer, you know the heat can be brutal--and much hotter than in the surrounding region.

Temperatures in cities tend to be several degrees warmer than in their rural areas, a phenomenon called the Urban Heat Island (UHI) effect. Many cities have been observed to be 2-4ºC warmer than the countryside in virtually every inhabited continent. This phenomenon occurs because urban infrastructure, especially pavements, absorbs a lot of heat as compared to natural vegetated surfaces. This heat pollution causes higher air conditioning and water costs, while also posing a public health hazard. Creating cooler cities

One mitigation strategy called gray infrastructure involves the modification of impermeable surfaces (walls, roofs, and pavements) to counter their conventional heating effect. Typical urban surfaces have a solar reflectance (albedo) of 0.20, which means they reflect just 20 percent of sunlight and absorb as much as 80 percent. By contrast, reflective concrete and coatings can be designed to reflect 30-50 percent or more. Cities like Los Angeles have already used reflective coatings on major streets to combat heat pollution, although the solution can be expensive to implement city-wide.

Researchers at the University of Pittsburgh Swanson School of Engineering used a Computational Fluid Dynamics model to find ways to decrease cost and increase usage of cooler surfaces. The paper examined the possibility of applying cooler surfaces to just half the surfaces in a city.

"This could be an effective solution if the surfaces selected were upstream of the dominant wind direction," said lead author Sushobhan Sen, a postdoctoral associate in the Department of Civil and Environmental Engineering. "A 'barrier' of cool surfaces preemptively cools the warm air, which then cools the rest of the city at a fraction of the cost. On the other hand, if the surfaces are not strategically selected, their effectiveness can decline substantially."

This research gives urban planners and civil engineers an additional way to build resilient and sustainable infrastructure using limited resources.

"It's important for the health of the planet and its people that we find a way to mitigate the heat produced by urban infrastructure," said coauthor Lev Khazanovich, the department's Anthony Gill Chair Professor of Civil and Environmental Engineering. "Strategically placed reflective surfaces could maximize the mitigation of heat pollution while using minimal resources."

Swiss scientist builds new model to simulate tsunami generation from iceberg calving

Tyler O'Neal, Staff Editor ECONOMICS

Johan Gaume, an EPFL expert in avalanches and geomechanics, has turned his attention to ice. His goal is to better understand the correlation between the size of an iceberg and the amplitude of the tsunami that results from its calving. Gaume, along with a team of scientists from other research institutes, has just unveiled a new method for modeling these events. 

These scientists are the first to simulate both glacier fracture and wave formation phenomena when the iceberg falls into the water. “Our goal was to model the explicit interaction between water and ice – but that has a substantial cost in terms of computing time. We, therefore, decided to use a continuum model, which is very powerful numerically and which gives results that are both conclusive and consistent with much of the experimental data,” says Gaume, who heads EPFL’s Snow Avalanche Simulation Laboratory (SLAB) and is the study’s corresponding author. The other institutes involved in the study are the University of Pennsylvania, the University of Zurich, the University of Nottingham, and Switzerland’s WSL Institute for Snow and Avalanche Research. Eqip Sermia glacier and its icebergs. © iStock

Improving calving laws
The scientists’ method can also provide insight into the specific mechanisms involved in glacial rupture. “Researchers can use the results of our simulations to refine the calving laws incorporated into their large-scale models for predicting sea-level rises while providing detailed information about the size of icebergs, which represent a sizeable amount of mass loss,” says Gaume.

Calving occurs when chunks of ice on the edge of a glacier break off and fall into the sea. The mechanisms behind the rupture generally depend on how high the water is. If the water level is low, the iceberg breaks off from the top of the glacier. If the water level is high, the iceberg is longer and breaks off from the bottom, before eventually floating to the surface owing to buoyancy. These different mechanisms create icebergs of different sizes – and therefore waves of different amplitudes. “Another event that can trigger a tsunami is when an iceberg’s center of gravity changes, causing the iceberg itself to rotate,” says Gaume. “We were able to simulate all these processes.”

In Greenland, the scientists placed a series of sensors at Eqip Sermia, a 3-km-wide outlet glacier of the Greenland ice sheet that ends in a fjord with a 200 m ice cliff. Back in 2014, an iceberg measuring some 1 million m3 (the equivalent of 300 Olympic-sized swimming pools) broke off the front of the glacier and produced a 50 m-high tsunami; the wave was still 3 m high when it reached the first populated shoreline some 4 km away. The scientists tested their modeling method on large-scale field datasets from Eqip Sermia as well as with empirical data on tsunami waves obtained in a laboratory basin at the Deltares Institute in the Netherlands.

Projects in the pipeline
Glacier melting has become a major focus area of research today as a result of global warming. One of the University of Zurich scientists involved in the study kicked off a new research project this year with funding from the Swiss National Science Foundation. This project will investigate the dynamics of Greenland's fastest-moving glacier, Jakobshavn Isbrae, by combining data from individual field experiments in Greenland with the results of simulations run using the SLAB model. “Our method will also be used to model chains of complex processes triggered by gravitational mass movements, such as the interaction between a rock avalanche and a mountain lake,” says Gaume.

Intel's chip sales plunge 20 percent in Q1

Tyler O'Neal, Staff Editor ECONOMICS

Intel has reported a huge drop in data center chip sales and a steep decline in gross profit margin, a sign it’s losing market share to rivals and customers who are designing their components. Intel shares were down 3% in after-hours trading after the results.

The company’s Data Center Group (DCG) has generated first-quarter 2021 sales of $5.6 billion, down 20% from a year earlier and below Wall Street estimates. This is one of Intel’s most profitable businesses, so the lower revenue hurt the overall margins.

In the fourth quarter of 2020, Intel's DCG revenue amounted to approximately $6.09 billion, a decrease of 15% from the figure reported for the same quarter of 2019.

Intel said sales of chips to cloud computing service providers fell 29% from the same period a year earlier. That big drop, according to Intel, was caused by “digestion” customers pausing orders while they work through unused stockpiles of chips.

Demand for cloud computing services from data centers has surged during the pandemic as many businesses shifted to working from home.

“This is a pivotal year for Intel. We are setting our strategic foundation and investing to accelerate our trajectory and capitalize on the explosive growth in semiconductors that power our increasingly digital world,” said Pat Gelsinger, Intel CEO.