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Engineering

How do tunnels under the water get built?

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Every day, thousands of people take the Tube from the north to the south of London or the Channel Tunnel to cross the English Channel. These routes are only possible because of something very important: tunnels that are underwater. But how does someone build something so amazing?

The shield for tunneling
Before French-British engineer Marc Isambard Brunel got an idea from nature in 1818, no one knew how to build an underwater tunnel. After seeing how the shell plates of a shipworm let it cut through wood, Brunel took that idea and made the tunneling shield bigger.

In this case, it was a huge, rectangular mold made of cast iron. The walls had shutter openings that were opened one at a time so that miners could dig into the soft ground outside. The shield was then moved forward with screw jacks, and the process started all over again. In the newly carved area behind, a protective “shell” of bricks was built around the tunnel.

Because of this, the first tunnel under the water was built under the River Thames in London. It was finished in 1842. In later tunnels under the Thames, the air in front of the shield was pressed down to try to stop flooding while the tunnels were being built.

Today, tunneling shields are still used. They are round and usually made of steel, which is also used to make the support rings for the tunnel. Modern versions also use hydraulic jacks to move the shield forward. There is a door in front of the shield that can be used when it’s not moving. Shields also have a protective hood on them for the people who go out to work there.

Machines that dig tunnels
Of course, digging through soft ground is one thing, but boring through rock under the water is something completely different. In this case, tunnel boring machines (TBMs), which were used to build the Channel Tunnel, changed the rules of the game dramatically.

The tunneling shield and the TMB both do the same thing, but the TMB uses a mechanical spinning cutting head to dig through the rock in front of it instead of people. It does this by putting stress on the rock, which breaks it up. There is no need for people to move the broken rock out of the way because it is taken back on a conveyor belt.

There are eleven TMBs that were used to dig the three 56.3-kilometer (35-mile) long tunnels. Some parts of the tunnels are 45 meters (148 feet) below the surface of the water.

Tunnels with immersed tubes
In the first two methods, the tunnel walls are built as the work is done, but there is another way to do it. Immersed tube tunneling is another method. W.J. Wilgus, an American engineer, was the one who created it.

With this method, the tunnel is built somewhere else first, with several sections already built, while a trench is dug into the riverbed or seabed where the tunnel will go. The pieces are then floated to the spot and sunk into place. The water is then drained from them, and dirt from the excavation is put on top of the tunnel to bury it and make the bed level again.

As Editor here at GeekReply, I'm a big fan of all things Geeky. Most of my contributions to the site are technology related, but I'm also a big fan of video games. My genres of choice include RPGs, MMOs, Grand Strategy, and Simulation. If I'm not chasing after the latest gear on my MMO of choice, I'm here at GeekReply reporting on the latest in Geek culture.

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Artificial Intelligence

Google DeepMind Shows Off A Robot That Plays Table Tennis At A Fun “Solidly Amateur” Level

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Have you ever wanted to play table tennis but didn’t have anyone to play with? We have a big scientific discovery for you! Google DeepMind just showed off a robot that could give you a run for your money in a game. But don’t think you’d be beaten badly—the engineers say their robot plays at a “solidly amateur” level.

From scary faces to robo-snails that work together to Atlas, who is now retired and happy, it seems like we’re always just one step away from another amazing robotics achievement. But people can still do a lot of things that robots haven’t come close to.

In terms of speed and performance in physical tasks, engineers are still trying to make machines that can be like humans. With the creation of their table-tennis-playing robot, a team at DeepMind has taken a step toward that goal.

What the team says in their new preprint, which hasn’t been published yet in a peer-reviewed journal, is that competitive matches are often incredibly dynamic, with complicated movements, quick eye-hand coordination, and high-level strategies that change based on the opponent’s strengths and weaknesses. Pure strategy games like chess, which robots are already good at (though with… mixed results), don’t have these features. Games like table tennis do.

People who play games spend years practicing to get better. The DeepMind team wanted to make a robot that could really compete with a human opponent and make the game fun for both of them. They say that their robot is the first to reach these goals.

They came up with a library of “low-level skills” and a “high-level controller” that picks the best skill for each situation. As the team explained in their announcement of their new idea, the skill library has a number of different table tennis techniques, such as forehand and backhand serves. The controller uses descriptions of these skills along with information about how the game is going and its opponent’s skill level to choose the best skill that it can physically do.

The robot began with some information about people. It was then taught through simulations that helped it learn new skills through reinforcement learning. It continued to learn and change by playing against people. Watch the video below to see for yourself what happened.

“It’s really cool to see the robot play against players of all skill levels and styles.” Our goal was for the robot to be at an intermediate level when we started. “It really did that, all of our hard work paid off,” said Barney J. Reed, a professional table tennis coach who helped with the project. “I think the robot was even better than I thought it would be.”

The team held competitions where the robot competed against 29 people whose skills ranged from beginner to advanced+. The matches were played according to normal rules, with one important exception: the robot could not physically serve the ball.

The robot won every game it played against beginners, but it lost every game it played against advanced and advanced+ players. It won 55% of the time against opponents at an intermediate level, which led the team to believe it had reached an intermediate level of human skill.

The important thing is that all of the opponents, no matter how good they were, thought the matches were “fun” and “engaging.” They even had fun taking advantage of the robot’s flaws. The more skilled players thought that this kind of system could be better than a ball thrower as a way to train.

There probably won’t be a robot team in the Olympics any time soon, but it could be used as a training tool. Who knows what will happen in the future?

The preprint has been put on arXiv.

 

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Engineering

New concrete that doesn’t need cement could cut carbon emissions in the construction industry

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Even though concrete is a very common building material, it is not at all the most environmentally friendly choice. Because of this, scientists and engineers have been looking for alternatives that are better for the environment. They may have found one: concrete that doesn’t need cement.

Cement production, which is a crucial ingredient in concrete, ranks as the third most significant contributor to human-caused carbon emissions globally. Nevertheless, in recent years, a multitude of alternative techniques for producing more environmentally friendly concrete have surfaced. One proposed method involves utilizing industrial waste and steel slag as CO2-reducing additives in the concrete mixture. Another suggestion is to utilize spent coffee grounds to enhance the strength of the concrete while reducing the amount of sand required.

However, a certain company has devised a technique to produce cement-free concrete suitable for commercial enterprises.

The concrete has the potential to have a net reduction in carbon dioxide and has the ability to prevent approximately 1 metric ton of carbon emissions for every metric ton used. If this statement is accurate, the cement-free binder will serve as a noteworthy substitute for Portland cement. According to BGR, the new concrete also complies with all the industry standards of traditional cement concrete, ensuring that there is no compromise in terms of strength and durability.

While it is still in the early stages, the situation seems encouraging. C-Crete Technologies, a company specializing in materials science and holding the patents for a novel form of concrete, has utilized approximately 140 tons of this new cast-in-place (pourable) concrete in recent construction endeavors.

In September 2023, the company was granted an initial sum of almost $1 million, promptly succeeded by an additional $2 million, by the US Department of Energy to advance the progress of its technology. In addition, it has garnered numerous accolades that are facilitating its growth in operations.

The widespread adoption of cement-free concrete in future construction projects has the potential to significantly alter the environmental impact of the industry. Although C-Crete seems to be one of the few companies currently exploring these new alternatives on a large scale, it is likely that others will also start embracing them in the near future.

 

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Engineering

To get gold back from electronic waste, the Royal Mint of the UK is using a new method

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There are hidden mountains of gold in the junkyards, full of old smartphones, computers that don’t work anymore, and broken laptops. A new project in the UK wants to find and use these hidden riches.
The Royal Mint, which makes British coins for the government, has agreed to work with the Canadian clean tech startup Excir to use a “world-first technology” that can safely get gold and other precious metals out of electronic waste (e-waste) and recycle them.

Electronic devices have circuit boards that have small amounts of gold in their connections because gold is a good conductor. These boards also have useful metals like silver, copper, lead, nickel, and aluminum.

In the past, getting the metals was hard, but Excir’s new technology can quickly and safely recover 99 percent of the gold that is trapped in electronic waste.

They prepare the circuit boards using a “unique process,” and then they use a patented chemical formula to quickly and selectively remove the gold. The liquid that is high in gold is then processed to make pure gold that can be melted down and formed into bars. Palladium, silver, and copper could also be recovered with this method.

“Our entrepreneurial spirit has helped the Royal Mint do well for over 1,100 years, and the Excir technology helps us reach our goal of being a leader in sustainable precious metals.” The chemistry is completely new and can get precious metals back from electronics in seconds. “It has a lot of potential for The Royal Mint and the circular economy, as it helps to reuse our planet’s valuable resources and creates new jobs in the UK,” said Sean Millard, Chief Growth Officer at The Royal Mint.

At the moment, about 22% of electronic waste is collected, stored properly, and recycled. But with this kind of new technology, the problem of old electronics could be lessened.

Every year, the world makes about 62 million metric tons of electronic waste, which is more than 1.5 million 40-tonne trucks’ worth. That number will go up by another 32% by 2030 as more people buy electronics. This will make it the fastest-growing source of solid waste in the world.

The World Health Organization says that e-waste is hazardous waste because it contains harmful materials and can leak harmful chemicals if it is not handled properly. For example, old electronics can release lead and mercury into the environment, which can affect the development of the central nervous system while a person is pregnant, as a baby, as a child, or as a teen. Also, e-waste doesn’t break down naturally and builds up in nature.

Aside from being a huge waste, this is also a big problem for the environment. There could be between $57 billion and $62 billion worth of precious metals in dumps and scrap yards.

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