Probably The Simplest Radiation Detector You Already Own

September 26, 2022 by Jenny List 78 Comments

Over the years we’ve featured quite a few radiatioactivity detectors, which usually include a Geiger-Muller tube, or perhaps a large-area photodiode. But in the event of radiation exposure from a nuclear attack, how does the man in the street gauge the exposure without owning a dedicated instrument? This was a question of note at the height of the Cold War, and it’s one that [Dr. Marshall Brucer] answered in a 1962 paper entitled “When Do You Leave A Fallout Shelter“. The full paper is behind a paywall but the part we’re interested in is on the freely available first page.

Dr. Brucer‘s detector is simplicity itself, and it relies on the erosion of a static electric charge by radiation. Should you rub a plastic comb in your hair it will accumulate enough charge to pick up a small piece of paper, and under normal background radiation the charge will ebb away such that it will drop the piece of paper after about 15 seconds. His calculation is that once the field reaches around 10 roentgens per hour it will be enough to erase the charge and drop the paper immediately. There’s a comtemporary newspaper report (Page 7, just to the left of the large advertisment) which tells the reader that since the exposure limit is 100 roentgens (one sievert), this test failing indicates that they have nine hours to create a better shelter. For obvious reasons we can’t test this at the Hackaday bench, but those of us who remember the days when such topics were a real concern will be searching for a handy comb anyway.

Thanks [Victor Matthew] for the tip.

Overhead satellite view of a coal-fired power plant next to a heat map showing the suitability of terrain in the region for siting a nuclear power plant

Coal To Nuclear Transition To Decarbonize The Grid

September 22, 2022 by Navarre Bartz 170 Comments

We love big projects here at Hackaday, and one of the biggest underway is the decarbonization of the electric grid. The US Department of Energy (DOE) recently published a report (PDF) on how placing nuclear reactors on coal plant sites in the US could help us get closer to the zero carbon grid of our dreams.

After evaluating both operating and recently retired coal-fired plants in the US, the researchers determined that around 80% of medium and large coal plants would be good candidates for coal to nuclear (C2N). Up to 263 GWe could be installed at over 315 different sites around the country which would be more than the 145 GWe expected to go offline as the remaining coal plants in the country shut down. Siting nuclear reactors at these existing sites could reduce installation costs 15-35% while also providing jobs for workers in the area who might otherwise be displaced when the coal plants shut down. Local greenhouse gas emissions (GHG) could drop up to 86% along with a significant drop in other air pollutants which would be another win for the fenceline communities living and working around these coal plants.

Nuclear power is certainly not without its drawbacks, but new reactor designs like TerraPower’s Natrium promise lower costs than current light water reactor designs while also being able to reuse the spent fuel from our current nuclear fleet. TerraPower is developing the first C2N project in the US at the Naughton Power Plant in Kemmerer, Wyoming.

We’ve recently covered Cogeneration and District Heating which would get a boost from more nuclear power, but, if that’s too grounded for you, might we suggest Space-Based Solar Power?

IGY: The Year We All Got Along

September 20, 2022 by Al Williams 24 Comments

If you are a Steely Dan fan, you might know the Donald Fagen song, “IGY.” In it, Fagen sings about a rosy future with high-speed undersea rail, solar power, giant computers making life better, and spandex jackets. Since that song was on the 1982 album Nightfly, it is already too old for some people to remember, but the title goes back even further: the International Geophysical Year which was actually a little longer than a year in 1957 and 1958. The year was a concerted effort by 67 countries to further mankind’s knowledge of the Earth. It was successful, and was big news in its day, although not much remembered now.

The real origin dates back to even earlier. In 1882 and 1932 there were International Polar Years dedicated to researching the polar regions of the Earth. In a way, it makes sense to do this. Why should 60 or more countries each mount difficult, dangerous, and expensive expeditions to such a hostile environment? However, instead of a third polar year, James Van Allen (who has a famous belt) and some other scientists felt that advances in many fields made it the right time to study geophysics. From the scientific point of view, the IGY coincided with the solar activity cycle maximum. But there were other forces at play, too.

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Multi-Stage Ion Thruster Holds Exciting Promise

September 19, 2022 by Tom Nardi 56 Comments

Anyone who’s looked into high-voltage experiments is likely familiar with ion lifters — spindly contraptions made of wire and aluminum foil that are able to float above the workbench on a column of ionized air. It’s an impressive trick that’s been around since the 1950s, but the concept has yet to show any practical application as the thrust generated isn’t nearly enough to lift a more substantial vehicle.

It’s a bit early to suggest that [Jay Bowles] of Plasma Channel has finally found the solution to this fundamental shortcoming of electrostatic propulsion, but his recently completed multi-stage ion thruster certainly represents something of a generational leap for the technology. By combining multiple pairs of electrodes and experimentally determining the optimal values for their spacing and operational voltage, he’s been able to achieve a sustained exhaust velocity of 2.3 meters per second.

Dry ice was used to visualize airflow through the thruster.

While most ion thrusters are lucky to get a piece of paper fluttering for their trouble, [Jay] demonstrates his creation blowing out candles at a distance of a meter or more. But perhaps the most impressive quality of this build is the sound — unlike most of the experimental ion thrusters we’ve seen, the air flowing through this contraption actually makes an audible roaring sound. When the 45 kilovolt supply voltage kicks in it sounds like a hair drier, except here there’s no moving parts involved.

In addition to providing graphs that show how air velocity was impacted by input voltage and the number and spacing of the electrode pairs, [Jay] also pops the thruster on a scale to show that there is indeed a measurable thrust being produced. Admittedly the 22 grams of thrust being generated isn’t much compared to the contraption’s own mass of 490 grams, but in the world of electrostatic propulsion, those are pretty impressive numbers.

[Jay] says he has some improvements in mind that he believes will significantly improve the device’s performance as he works towards his ultimate goal of actually flying an ion-propelled aircraft. We saw MIT do it back in 2018, and it would be great to see an individual experimenter pull off a similar feat. Obviously, there’s still a long way to go before this thing takes to the skies, but if anyone can pull it off, it’s [Jay Bowles].

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Sappers clearing the last mines from the beach front of a former French luxury hotel, now in use as a rest club for troops of 3rd Division, 15 July 1944.

The Long Tail Of War: Finding Unexploded Ordnance Before It Finds Us

September 19, 2022 by Maya Posch 38 Comments

Long after the enemy forces have laid down their arms, peace accords have been signed and victories celebrated, there is still a heavy toll to be paid. Most of this comes in the form of unexploded ordnance, including landmines and the severe pollution from heavy metals and other contaminants that can make large areas risky to lethal to enter. Perhaps the most extreme example of this lasting effect is the Zone Rouge (Red Zone) in France, which immediately after the First World War came to a close comprised 1,200 square kilometers.

Within this zone, contamination with heavy metals is so heavy that some areas do not support life, while unexploded shells – some containing lethal gases – and other unexploded ordnance is found throughout the soil. To this day much of the original area remains off-limits, though injuries from old, but still very potent ordnance are common around its borders. Clean-up of the Zone Rouge is expected to take hundreds of years. Sadly, this a pattern that is repeated throughout much of the world. While European nations stumble over ordnance from its two world wars, nations in Africa, Asia and elsewhere struggle with the legacy from much more recent conflicts.

Currently, in Europe’s most recent battlefield, more mines are being laid, booby traps set and unexploded shells and other ordnance scattered where people used to live. Clearing these areas, to make them safe for a return of their inhabitants has already begun in Ukraine, but just like elsewhere in the world, it is an arduous and highly dangerous process with all too often lethal outcomes.

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As Europe Goes To LEDs, Scientists Worry

September 19, 2022 by Al Williams 271 Comments

There was a time when street lighting means someone had to go light the lamps. Electricity changed that, but street and outdoor lighting has been quietly going through a new revolution: LEDs. The problem, though, is that LEDs provide what scientists call “broad white” light and there are concerns about the impact the unnatural lighting will have on ecosystems, including people and animals.

Of course, the first step in worrying about something is to measure it. You would think that satellites would have a bird’s-eye view of the nighttime lighting landscape, and, of course, they do. But most of the imagery isn’t suitable for looking at the spectrum of wavelength data scientists need to quantify what they call ALAN — Artificial Light at Night.

The ISS imaging is, however, sufficient. Using special data techniques, they were able to track the adoption of LEDs over sodium lights and other technologies between 2012-2013 and 2014-2020 across Europe. For example, in the title image, you can see Belgium with an orange tint indicating low-pressure sodium lights. The Netherlands, France, and the UK have a more yellow hue, indicating high-pressure sodium lamps. Germany is more of a blue color due to fluorescent and mercury vapor bulbs.

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Groundwater: Management Of A Much Neglected Lifeline

September 13, 2022 by Maya Posch 14 Comments

It seems obvious that if you dig or drill into the soil, at some point you will hit groundwater. Drill deep enough and you will reach an aquifer containing enormous amounts of fresh water. After this you can just pump water out of these wells and you will have fresh water aplenty. Or so was the thinking among many for the longest time. As enormous the fresh water reserves in the form of groundwater are – with most liquid fresh water being groundwater – we can literally empty them faster than that they’ll refill.

As the Dust Bowl disaster painfully showed in the 1930s and drought along with surface subsidence issues as in e.g. California’s Central Valley shows today is that we cannot simply use the soil and groundwater and expect no consequences. While the 19th century saw many fresh settlers to the West’s arid and semi-arid regions like California believe in the ‘Rain follows the plow‘ mysticism, the 20th century and these first few decades of the 21st century taught us that tilling the soil and drawing groundwater for irrigation does not change an arid climate into a lush one.

Perhaps ironically, even with increasing droughts, most human settlements use stormwater drainage and combined sewage systems to carry rainwater away, rather than letting the groundwater recharge naturally. Fortunately, more and more regions these days are seeing the necessity of managing groundwater.

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