News by Subject Technology & Engineering

Dissolved oxygen in pore solution is often a controlling factor determining the rate of the corrosion process of steel bars in concrete. This study reports on the corrosion resistance and polarization properties of steel bars in a mortar specimen mixed with aerobic microorganisms. The addition of the microorganisms in mortar mixtures led to higher corrosion resistance, which was confirmed by the reduced rate of oxygen permeability, based on cathodic polarization properties.

A team of engineers at UC San Diego has discovered a method that could make materials more resilient against massive shocks such as earthquakes or explosions. They found that cutting small grooves in obstacle materials diminished the impacts of what's called the reflected shock wave--once the initial wave has hit the spiral of obstacles and bounced back.

Many industrial buildings rely on ultrasound instruments that continually monitor the structural integrity of their systems without damaging or altering their features. One new technique draws on laser technology and candle soot to generate effective ultrasonic waves for nondestructive testing and evaluation. Researchers are using ultrasonic nondestructive testing that involves amplifying the signal from a photoacoustic laser source using laser-absorbing patch made from an array of nanoparticles from candle soot and polydimethylsiloxane.

In summer heat, cities may swelter more than nearby suburbs and rural areas. And while the size of this urban heat island effect varies widely among the world's cities, heat island intensity can largely be explained by a city's population and precipitation level, researchers reported in a paper published Sept. 4 in the journal Nature. The analysis suggests that cooling cities by planting more vegetation may be more effective in drier regions than in wetter ones.