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How to make low-carbon concrete from old cement

The world gets a little greyer every year. According to a paper published in 2014 concrete—an aggregate material made by mixing cement, sand and gravel—is the second-most consumed substance in the world after water.


A new way to clean up the steel industry

Making steel is a dirty business. For every tonne of it some 1.8 tonnes of carbon dioxide (CO2) are emitted into the atmosphere. As a result, steelmaking accounts for 7-9% of the world’s anthropogenic greenhouse-gas emissions. Cleaner ways of…


Most children in poor countries are being failed by their schools

“Good job you!” shouts Pauline Bika, as a group of schoolchildren completes the hokey-cokey. “Good job me!” choruses her class. Ms Bika runs a small government primary school in Edo state, in southern Nigeria. It is reached by a mud track that…


A better way of keeping mosquitoes at bay is under development

Mosquito repellents have come a long way. For decades, the market leader was DEET, which fends the pests off successfully, but only for an hour or two. Recently, Icaridin has become available. This lasts up to eight hours and is just as effective.


Wasp larvae that eat aphids alive may save apple crops

Few insects strike greater fear into the hearts of orchard-owners than rosy apple aphids. These tiny bugs feed on the leaves of apple trees, draining them of nutrients.


Adding bacteria can make concrete greener

Concrete is one of the world’s most important materials. But making the cement that binds it generates about 8% of anthropogenic carbon-dioxide emissions. This is not just because of the heat involved. That could, in principle, be supplied in…


Alien plants and animals are not all bad

Introduced species have a bad rap. From American grey squirrels displacing European red ones, to Japanese knotweed displacing just about everything everywhere, their purported negative effects on nature are there for all to see.


Gigafactories are making greener EV batteries by recycling old ones

Though dark satanic mills are long gone from industry, the start of the lithium-ion-battery production line in a factory in Vasteras, west of Stockholm, is particularly squeaky clean.


A new malaria vaccine shows promising results

Most diseases that used to kill children in large numbers have succumbed to vaccines. Malaria is an exception. In 2020 it killed 640,000 people, mostly African children under five years old. Scientists have not ignored the scourge: the first…


How to preserve secrets in a quantum age

It is not often that a bit of mind-bending mathematics can avert disaster. But researchers at America’s National Institute of Standards and Technology (nist) have done their bit: last week, after years of analysis, they gave their stamp of approval…


Robotised insects may search collapsed buildings for survivors

Why Go To all the trouble of designing and building a drone if nature has already done most of the job for you? That is the attitude taken by the small but determined band of researchers who are trying to robotise insects.


Two new ways of extracting lithium from brine

Around 60% of the world’s lithium, a metal in high demand for making batteries, comes from evaporation ponds, like that pictured overleaf, located in deserts in Argentina, Bolivia and Chile.


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