ETH News
All stories that have been tagged with Sustainability
Previously unknown compound in chloraminated drinking water identified
News
Since the 1980s, its been known that a mysterious contaminant forms in chloraminated drinking water, but only now has a Swiss-American research team been able to identify the unknown product in US drinking water systems.
Towards a restless retirement
News
Marco Mazzotti will be conferred emeritus status at the end of January 2025. A good reason for a portrait of this dedicated process engineer, who came to his field of research quite unexpectedly.
Researchers are making jet engines fit for the hydrogen age
News
Hydrogen-powered planes are set to take wing around the world in the future. To make this possible, engineers have to develop the jet engines that will power them. Experiments by researchers at ETH Zurich are now providing the necessary basis for making these engines powerful and durable.
Strengthening the Swiss electricity grid with copper and brains
News
A secure supply of electricity from renewable energies can only succeed if we also modernise the grid infrastructure. At the Energy Science Centre (ESC), ETH researchers are looking for smart ways to make the electricity grid fit for the energy transition without expensive expansion.
“Geoengineering will not solve the problem of climate change”
News
A team led by ETH climate researcher Sandro Vattioni has shown that diamond dust released in the atmosphere could be a good way to cool the climate. However, it is still not a sustainable solution to climate change, says Vattioni in an interview with ETH News.
Biofabrication should be sustainable
- News
- Zukunftsblog
While living matter can advance technology and render human activities more efficient and eco-friendly, the way in which we currently fabricate materials containing living cells is far from sustainable. Miriam Filippi calls us to rethink our biofabrication practices.
How an ETH alumnus ended up growing coffee in Zambia
- News
- Homehero
- Globe magazine
ETH agronomist Fridolin Stocker worked on Swiss farms before discovering his fascination for Africa. Today he manages a coffee farm in Zambia.
How Ukraine can rebuild its energy system
News
Researchers at ETH Zurich have been working with researchers from Ukraine and Germany to investigate how to rebuild Ukraine’s destroyed energy infrastructure based on renewable energy. They have determined that solar and wind energy would quickly deliver a distributed power supply system and prevent corruption.
Printing with earth-based materials
News
ETH Zurich researchers have developed a fast, robot-assisted printing process for earth materials that does not require cement.
The state of biodiversity is not a matter of opinion
- News
- Zukunftsblog
Ahead of the vote on the biodiversity initiative, basic insights on the state of biodiversity and habitats in Switzerland are being discussed controversially. Lo?c Pellissier counters by holding up the scientific consensus.
Chemical plastics recycling is ready to go
News
Scientists around the world can now go full throttle in their research into chemical plastics recycling. Researchers at ETH Zurich have laid important foundations for this by showing that it’s all about the stirring.
ETH research supply support to the Swiss state
Globe magazine
From devising forecasting models for the Federal Finance Administration and describing the latest trends in civil protection, ETH researchers routinely supply vital support to the Swiss state and help drive innovation.
We should not underestimate the increasingly warm summer temperatures
- News
- Zukunftsblog
Despite a wet and grey June, summers in Switzerland are getting hotter than expected. The increased summer temperatures harbour risks that we are not well prepared for, says Dominik Schumacher.
Mining rare earth metals from electronic waste
News
ETH researchers are developing a process inspired by nature that efficiently recovers europium from old fluorescent lamps. The approach could lead to the long-awaited recycling of rare earth metals.
Light green hydrogen will do
Whether sustainably produced hydrogen needs to be 100 percent green is currently under debate. Using the production of ammonia and artificial fertiliser as examples, researchers have calculated that "nearly sustainable" hydrogen would be better in the end.
This researcher reads rivers
- News
- Homehero
Jessica Droujko’s start-up, Riverkin, measures the water quality of freshwater ecosystems and helps quantify and respond to risks such as floods and pollution. Thanks to an ETH Pioneer Fellowship, her work is now picking up speed.
CLIMADA scoops first prize at Venture Awards
News
Eighteen start-ups were awarded prizes at this year’s Venture Awards, including five ETH Zurich spin-offs. CLIMADA won first prize in the Finance & Insurance category.
From student project to personalised sandals from a 3D printer
- Globe magazine
- Homehero
Start-up URBNC 3 produces sustainable and personalised sandals with the aid of digital technology. The start-up took its first steps at the Student Project House of ETH Zurich.
Electrifying industry with flexible heat pumps
- News
- Homehero
Researchers from ETH Zurich and the Eastern Switzerland University of Applied Sciences have developed a novel solution for heat pumps. Using this new approach, companies can generate carbon-free process heat at temperatures of up to 200 degrees Celsius while also drastically reducing the number of different heat pumps required.
How can we tax electric cars without slowing down the electromobility transition?
- Zukunftsblog
- News
The federal government has plans to tax electric vehicles to secure funding for road infrastructure. However, a new levy could delay the switch to electromobility. Alessio Levis explains how this dilemma could be resolved.
The mystery of cathodic corrosion protection clarified
News
Cathodic corrosion protection is a widely used technique for protecting steel-based infrastructure from corrosion. ETH researchers have now clarified the detailed mechanisms involved, thereby resolving a controversial issue that had preoccupied the engineering community for decades.
When stones start rolling
- Homehero
- News
The landslide in Brienz (GR) in 2023 kept Switzerland on tenterhooks for weeks. Researchers from ETH Zurich, WSL and SLF used a model to provide a highly accurate blind prediction of where the sliding mass would come to rest. ETH Professor Johan Gaume explains how the model works and where its limitations lie.
ETH Zurich sets course for Net Zero
News
ETH Zurich announces its expedition towards climate neutrality today with pop-up events by students and the first Net Zero Day. The "ETH Net Zero" programme supports the reduction of emissions by 2030 and offers people plenty of ways to get involved.
Chocolate that harnesses the full potential of the cocoa fruit
News
Researchers at ETH Zurich have teamed up with the food industry to produce a whole-fruit variety of chocolate. This helps increase the value creation of cocoa farming – and is healthier.
Thinking climate action, biodiversity and energy supply together
- Zukunftsblog
- News
Renewable energies are not the main driver of biodiversity loss. It is rather the other way round: renewables can limit climate change in order to preserve biodiversity. Cyril Brunner contextualises the trade-offs from a scientific perspective.
Using solar energy to generate heat at high temperatures
News
Instead of burning coal or oil to produce cement or steel, in the future solar energy could be used for this purpose. Researchers at ETH Zurich have developed a thermal trap that can absorb concentrated sunlight and deliver heat at over thousand degrees Celsius.
Mosaic grassland landscapes are the most beneficial
Like forests, grassland provides numerous ecological, economic and social benefits. Researchers have investigated ways to maintain and improve these benefits in the Swiss canton of Solothurn.
Bacteria for climate-neutral chemicals of the future
News
Researchers at ETH Zurich have engineered bacteria in the laboratory to efficiently use methanol. The metabolism of these bacteria can now be tapped into to produce valuable products currently made by the chemical industry from fossil fuels.
Strengthening Swiss hydropower with science
News
Researchers at ETH Zurich led by Robert Boes are developing specific solutions to optimise electricity production from Swiss hydropower plants. This will ensure that hydropower remains the backbone of Switzerland’s electricity supply in the future.
How micro- and nanoplastics are infiltrating the Arctic ice
News
Environmental scientist Alice Pradel cultivates ice cores in the lab to investigate the transport and accumulation of micro- and nanoplastics. Her aim in doing so is to better understand material flows in the Arctic ice.
Climate-friendly renovations using straw and hemp
- News
- Homehero
Renovating buildings to improve their energy efficiency is a crucial step towards Switzerland achieving its climate targets. ETH Zurich researchers can now reveal the most effective renovation strategies for reducing greenhouse gas emissions: replace fossil-fuel heating systems and harness the potential of bio-based building materials like straw and hemp.
Pesticide-free as a new pathway for agriculture
- News
- Zukunftsblog
We can transition to pesticide-free agriculture without converting to organic farming. Robert Finger outlines the advantages and challenges involved.
Allies from the deep
- Globe magazine
- Homehero
Estelle Clerc searches remote waters such as the deep ocean for bacteria that can degrade specific pollutants such as microplastics, pharmaceuticals and pesticides.
The man for freak events
News
Christoph Sch?r is one of the Swiss climate scientists who have shaped high-resolution climate modelling. He is now retiring after more than 35 years at ETH Zurich. In this portrait, he explains why he himself never tires of researching climate change.
Cost of direct air carbon capture to remain higher than hoped
News
The cost of removing large quantities of CO2 from the air will fall in the medium term, but not as much as previously hoped. This is the conclusion reached by ETH researchers on the basis of new calculations. Efforts to reduce carbon emissions should therefore continue at pace, says the research team.
Turning waste into gold
News
ETH Zurich researchers have recovered the precious metal from electronic waste. Their highly sustainable new method is based on a protein fibril sponge, which the scientists derive from whey, a food industry byproduct.
A sustainable fuel and chemical from the robotic lab
News
Artificial intelligence and automated laboratory infrastructure are massively accelerating the development of new chemical catalysts. With these tools, researchers at ETH Zurich are developing catalysts for efficiently and cost-effectively synthesising the energy source methanol from CO2.
Switzerland needs to do a better job of exploiting its innovation potential
- News
- Zukunftsblog
Switzerland offers tremendous opportunities for technological and entrepreneurial innovation. Thomas Zurbuchen asks, “How can we generate the momentum needed to maintain an edge in the face of international competition – especially when times get tough?”
Innovative coating prevents limescale formation
News
Wherever hot water flows, limescale is never far away. In households, this is a nuisance; in thermal power stations, it’s an expensive problem. Now researchers at ETH Zurich have found an answer.
Midday sun at the touch of a button
News
At ETH Zurich, there is a room where the sun shines at the touch of a button; one hour it’s noon in the Sahara, the next it’s January in Berlin. Researchers use it to test newly developed building systems, components and materials.
Groundwater levels are sinking ever faster around the world
News
A global study shows that the world’s groundwater resources are dwindling: levels are falling sharply worldwide, and the decline has accelerated in the 21st century. Nevertheless, there is still reason for hope.
Hydrogen: handle with care
- News
- Zukunftsblog
For Anthony Patt, Europe’s ambitious plans for a hydrogen economy may be too ambitious, tipping the scales towards the interests of the fossil fuel industry, rather than energy consumers and the climate. Switzerland should be careful before jumping fully on board, he argues.
World’s most powerful supercomputers support UN SDGs and global sustainability
- Press release
- Homehero
- News
The Federal Department of Foreign Affairs (FDFA) and ETH Zurich, in collaboration with their international partners, are launching the International Computation and AI Network (ICAIN) at the World Economic Forum (WEF) 2024 in Davos. Its mission is to develop AI technologies that benefit society as a whole, as well as being accessible to all and sustainable, thereby helping to reduce global inequality.
Capturing greenhouse gases with the help of light
News
Researchers at ETH Zurich are developing a new method to remove CO2 from the atmosphere. It involves molecules that become acidic when exposed to light. Their new process requires much less energy than conventional technologies.
Watt d’Or for efficient and sustainable power supply with photovoltaics
- News
- Homehero
ETH Zurich researchers from the Automatic Control Laboratory and the electricity supplier AEW Energie AG have won the 2024 Watt d’Or award in the Energy Technologies category. Their algorithm, which was implemented at AEW Energie, makes it possible to optimise electricity grid operations.
Three strategies to boost green electricity in Switzerland
News
Climate neutrality and nuclear phase-out: Switzerland's ambitious green electricity targets are realistic if the electricity supply is profoundly and rapidly transformed, as a study by the SWEET EDGE consortium shows. The researchers developed three strategies for expanding renewable energies.
Let’s talk about solutions
- News
- Zukunftsblog
More and more people are afraid of climate change. For Cyril Brunner, this also has to do with how we talk about climate. We should focus less on problems and instead spend more time discussing solutions, suggests the climate researcher at the start of the year.
Accurate snow measurement thanks to AI and satellites
News
Snow measurement has never been so fast and accurate: ETH Zurich researchers have developed an artificial intelligence capable of determining snow depth across Switzerland using satellite images.
What should be done with all the carbon dioxide?
Press release
Capturing carbon dioxide (CO2) from the atmosphere and storing it either in recycled concrete aggregate or in geological reservoirs in Iceland is not only technically feasible, but also has a positive carbon footprint. These are the findings of a pilot project lead by ETH Zurich and commissioned by the Swiss confederation.
A forensic look at biodiversity
- Globe magazine
- Homehero
From the giant blue whale to minuscule microbes, all creatures on this earth continuously shed traces of their DNA. These clues help researchers to determine the degree of biological diversity.
How Zurich has to change its roads to have more e-bikes than cars
News
What happens when cities gear their road space primarily to the needs of cyclists and e-bikers? On a new popular-science website, ETH researchers use examples from the city of Zurich to show what such an “E-Bike City” could one day look like.
Lightweight insulating building elements from a 3D printer
News
A doctoral researcher studying architecture at ETH Zurich is using 3D printing to produce lightweight insulation building components from cement-free mineral foams derived from recycled industrial waste. These could cut heating and cooling costs for buildings, and encourage more efficient use of construction materials.
A CAS in the repairability of buildings and products
News
ETH is offering a new continuing education programme in the serviceability and repairability of buildings and products. The CAS is backed by an architect, a product developer and a production technologist.
Natural coasts protect against tropical cyclones
News
People living on the in low-lying coastal areas will be at even greater risk from cyclones in the future. Natural ecosystems offer protection, but this protection has decreased in recent years and is expected to continue to decline. This is a finding of a model study by an international team of researchers led by ETH Zurich.
Green change in a grey industry
- News
- Homehero
ETH researchers are developing a low-carbon cement with a significantly lower embodied CO2 content than traditional cement. The Ultra Green Concrete project aims to make low-carbon, high-performance concrete widely accessible.
An excellent pavilion for circular construction
News
In a practical teaching project, ETH students used materials from the demolished Huber Pavilions to construct a building in the spirit of the circular economy. The Re-Use Pavilion on the ETH H?nggerberg campus has now been honoured with an Arc Award.
3D printed reactor core makes solar fuel production more efficient
News
Using a new 3D printing technique, researchers at ETH Zurich have developed special ceramic structures for a solar reactor. Initial experimental testing show that these structures can boost the production yield of solar fuels.
Tackling water stress in the Swiss Alps
- News
- Zukunftsblog
The Alps are being increasingly affected by floods and droughts. According to Manuela Brunner, we can do something about this problem: use water more sparingly and think about hazard protection in broader terms.
Generating clean electricity with chicken feathers
News
Turning unused waste from food production into clean energy: Researchers at ETH Zurich and Nanyang Technological University Singapore are using chicken feathers to make fuel cells more cost-effective and sustainable.
ETH Zurich researchers study one of the world’s darkest rivers
News
They set out to study the Congo Basin’s carbon cycle and in the process have become aware of one of the world’s darkest blackwater rivers: the Ruki. In the first study on this major jungle river, an international research team led by ETH Zurich explains how this blackness comes about and what it says about the river system’s carbon balance.
Research that provides sustainable and nutritional benefits
News
ETH Zurich is present at the Olma trade fair in St Gallen. Using spin-offs and games, the ETH booth illustrates how research can contribute to making Swiss food and agriculture sustainable.
“We’re living in yesterday’s future scenarios”
News
ETH Professor Sonia Seneviratne has been elected as Vice-Chair of the Working Group I of the Bureau of the Intergovernmental Panel on Climate Change (IPCC). In order to take on this new responsibility, she is stepping down as Associate Vice President for Sustainability at ETH Zurich. In this interview she talks about her old and new positions.
Ocean acidification in coloured stripes
News
Our oceans are acidifying rapidly. Climate researchers from ETH Zurich are now illustrating these chemical changes with colour-coded stripes. Global observations of ocean acidification over the last four decades serve as the basis.
A change of perspective
Globe magazine
Strategy games developed by ETH ecologists bring different stakeholders to the table. By shifting people’s perspectives, they create a win-win situation for environmental protection.
Heatwaves are becoming more frequent and more deadly
News
The risk of fatal heatwaves has risen sharply over the past 20 years. In the future, such extreme weather will become more frequent and heat-related excess mortality will increase. Europe will be particularly affected, as ETH Zurich researchers show.
Made from waste instead of trees
- Homehero
- News
- Globe magazine
The start-up Treeless Pack produces cellulose with microorganisms - entirely without wood. The cellulose can be used to produce paper, packaging material or composites for the construction industry in a resource-saving way.
Biodiversity protects against invasions of non-native tree species
News
For the first time, researchers combined human and ecological factors to analyse the global scale of non-native tree species invasions. Human activity in hotspots of global trade, such as maritime ports, is linked to an increased likelihood of non-native tree species invasions. However, a high diversity of native tree species can help to curb the intensity of such invasions.
Valuable raw materials from olive waste
News
ETH spin-off Gaia Tech transforms waste from olive oil production into high-quality antioxidants for use in cosmetics or food. This turns waste into valuable raw materials.
Collecting clean water from fog
News
Researchers at ETH Zurich have demonstrated the use of a specially coated metal mesh to harvest water from fog and simultaneously remove pollutants. People living in dry but foggy areas should benefit from this technology.
Building models to predict interactions in plant microbiomes
News
Microbiologists at ETH Zurich have developed computational models that use nutrients and metabolism of plant-associated bacteria to predict how the microbes interact on the surface of leaves and ultimately form the microbiome.
How an ocean-fertilising bacterium forms aggregates
News
Trichodesmium, a common and ecologically important bacterium, fertilises nutrient-poor regions of the oceans and thereby enables higher life. Crucial to its success is its ability to form aggregates in order to react quickly to changes in its environment. ETH Zurich researchers have shown how the microbes organise themselves in this process.
Global warming accelerates CO2 emissions from soil microbes
News
When microorganisms break down organic material in the soil, they actively release CO2 into the atmosphere. This process is called heterotrophic respiration. A novel model shows that these emissions could surge by up to 40 percent by the end of the century – most significantly in the polar regions.
A world in flux
- Globe magazine
- News
Heavier rain, longer droughts, melting glaciers: climate change has a dramatic impact on the global water cycle.
Can Switzerland transition to a secure renewables-based energy system? Absolutely!
- Zukunftsblog
- News
Gabriela Hug – an expert in power transmission networks – argues that securing an affordable energy supply from renewable sources is not a utopian ideal for Switzerland, but rather a practical and feasible necessity.
A contested resource
- Globe magazine
- News
The expansion of hydropower generation often leads to conflicts of interest, both in Switzerland and beyond. Researchers from ETH Zurich are trying to find a basis for compromise that serves the public interest.
New power for the energy market
- Globe magazine
- News
- Homehero
During her doctoral studies, Liliane Ableitner developed a trading and billing tool for energy communities. Three years on, she is CEO of a flourishing start-up with 20 employees.
Droughts increasingly reduce CO2 uptake in the tropics
- News
- Homehero
ETH Zurich researchers have found that droughts and land water variability have had an increasing effect on the carbon cycle in the tropics over the last sixty years. Most climate models fail to capture this observation. This could mean that terrestrial ecosystems could absorb less CO2 than expected in their role as carbon sinks in the future.
Energy security in a climate-neutral Switzerland is possible
- News
- Homepage
Security of energy supply in a fossil-free Switzerland is feasible and affordable according to a new white paper from an expert group at the Energy Science Center. It will require increased production of renewables and efficient energy trading with neighbouring countries.
From robotic fish to artificial muscles
News
Bachelor’s students at ETH Zurich were given a year to turn their original ideas into finished products. ETH News presents videos of two of these projects.
Why the Swiss are shipping CO2 to Iceland
News
Yesterday, Swiss President Alain Berset toured the Carbfix plant in Iceland and visited the facilities where the pilot project "DemoUpCARMA" is implemented. The project aims at injecting and storing CO2 in the Icelandic underground. Marco Mazzotti, project coordinator and ETH Zurich professor, explains why Swiss CO2 is being shipped all the way to Iceland.
Why we need electricity trade
- News
- Zukunftsblog
To decarbonize our economy, electricity will replace oil and natural gas as the primary energy carrier. Where should that power come from? Many people argue that all of it should be produced domestically. Careful analysis suggests some share of it should be imported, says Anthony Patt.
A survey of genetic diversity among native Swiss living organisms
- News
- Homehero
Switzerland is monitoring its biological diversity as part of a global effort to understand its changes and prevent further biodiversity loss. Researchers from ETH Zurich are working on a pioneering pilot study that includes the analysis of genetic diversity of native species.
Why we are taking a stand on the Swiss Climate Protection Law
- Zukunftsblog
- News
- Homepage
Political debate is vital for a functioning democracy. And when it comes to complex issues such as climate change, scientists should be able to share their expertise and help shape opinion, says Reto Knutti.
Student-made sensor facilitates climate-conscious design of public squares
- News
- Homepage
ETH students have developed sensors that can indicate how people use urban spaces. They anonymously measure how people use objects such as chairs in a public square. The sensors have proven useful in the test run and could be used in future to plan public spaces based on needs.
Why are forests turning brown in summer?
- News
- Homepage
Increasing summer heat and drought are affecting European forests – some years, trees brown prematurely and some even start to die back. Researchers from ETH Zurich and the WSL are showing how exceptional weather conditions over several years are turning forests brown.
Following the water cycle in the forest
News
In the Forest Laboratory "Waldlabor" on H?nggerberg, ETH Zurich researchers investigate the storage and transport processes of water in the forest. Recently they showed that forest-floor litter and deadwood have a far larger influence on the forest water balance than expected.
Where should wind turbines be constructed in Switzerland?
News
A study by researchers at ETH Zurich shows for the first time how a relaxation of Swiss spatial planning policy would affect the locations of wind turbines. If the aim is to have as few wind turbines as possible in the Alps and in Switzerland in general, it would be worth considering using windy agricultural areas on the western Swiss Plateau.
Maren Brehme on geothermal energy
- News
- Homepage
In the video series "Ask the Expert", ETH Zurich experts answer questions from the community. In this edition, Maren Brehme provides information on the topic of geothermal energy.
A wholly sustainable plastics economy is feasible
- News
- Homepage
A new study shows what it will take for the plastics industry to become completely sustainable: lots of recycling combined with the use of CO2 from the air and biomass. It is also the image of plastics that need to change.
Switzerland wants a circular economy – but not to share products
- News
- Homepage
ETH Zurich political science researchers reveal that Swiss people are in favour of the circular economy and support measures to promote it. However, their personal willingness to contribute is low.?
No climate neutrality without critical raw materials
- News
- Homepage
- Zukunftsblog
Europe’s energy transition will not succeed without access to essential metals like rare earths, says security researcher Julian Kamasa. Responsible mining and recycling of critical raw materials could help Europe reduce dependence on imports and meet its climate targets. ?
The complex interplay behind great heat
- News
- Homepage
Many regions have suffered from heatwaves in recent years. But exactly how these form is still a matter of debate. Two researchers at ETH Zurich have now found a nuanced answer.
Patchwork of issues limits solar expansion
- Press release
- Homepage
Whether rooftop solar panels are worth the cost is largely dependent in Switzerland on local compensation rates for solar power and on electricity prices in general – these are the findings of a study by researchers at ETH Zurich and the University of Bern. Many power grid operators pay too little, thereby limiting the expansion of solar power.
How microbial communities shape the ocean’s ecology
- News
- Homepage
A research collaboration led by ETH Zurich and MIT will receive a further USD 15 million from the New York-based Simons Foundation to investigate the behaviour of marine bacteria and microalgae. The research will focus on microbial communities that impact the ocean’s carbon cycle.
Restoring nature equitably
- News
- Homepage
- Zukunftsblog
Efforts to restore degraded ecosystems have so far fallen short of meeting global targets. Sound restoration must better incorporate social processes promoting equity in order to effectively benefit people, climate and biodiversity, says Sara L?fqvist.
Alien plant species are spreading rapidly in mountainous areas
- News
- Homepage
Until now, mountain regions have been largely spared from biological invasions. But a new monitoring study shows that alien plants are spreading rapidly to higher altitudes along transport routes worldwide.
How grasses avoid inbreeding
News
ETH Zurich researchers have been able to show which genes inhibit self-fertilisation in grasses. Plant scientists can now use this mechanism in a more targeted way to breed new varieties of forage grasses as well as rice or barley.
A snow-free Switzerland?
- News
- Zukunftsblog
There has been a great deal of media focus on the near-total lack of snow in Swiss ski resorts at the beginning of the year. Sonia Seneviratne explains why we will have to get used to this scenario and what needs to be done about it.
Immediate uptick in investment needed to reach net zero
News
A new study by ETH Zurich researchers reveals that if Europe fails to immediately invest 302 billion euros in climate-relevant infrastructure, it will not reach its target of net-zero greenhouse gas emissions by 2050.
An eye on reconstruction in Ukraine
News
Ukrainian building materials professor Viacheslav Troian left his homeland with his family because of the war. At ETH Zurich, he is researching the role that recycled concrete might play in future reconstruction.