How To Make A Difference Through Plant Metabolism

June 7, 2022 by 31 Comments

Generally when we consider the many plants around us, we imagine them efficiently using the electromagnetic radiation from the Sun via photosynthesis in their leaves — pulling carbon-dioxide from the air, as well as water from the soil via their roots, and grow as quickly as they reasonably can. In reality, the efficiency of this process is less than 10% of the input energy, and the different types of plant metabolisms that have formed over the course of evolution aren’t all the same.

Among the plant metabolisms in use today, some use significantly more efficient carbon fixation pathways, while others end up wasting a lot of the energy they obtained from photosynthesis with unnecessarily complicated processes, especially to deal with waste. How fast plants can grow if they had all evolved the most efficient carbon fixation pathway has been the subject of a number of studies these past decades, involving everything from crop plants to trees.

As these studies are showing us, more than a scientific and evolutionary biological curiosity, these genetically engineered plants offer real opportunities in everything from food production to reforestation.

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Laser Propulsion Could Satisfy Our Spacecraft’s Need For Speed

June 6, 2022 by 51 Comments

There are many wonderful places we’d like to visit in the universe, and probably untold numbers more that we haven’t even seen or heard of yet. Unfortunately…they’re all so darn far away. A best-case-scenario trip to Mars takes around six months with present technology, meanwhile, if you want to visit Alpha Centauri it’s a whole four lightyears away!

When it comes to crossing these great distances, conventional chemical rocket technology simply doesn’t cut the mustard. As it turns out though, lasers could hold the key to cutting down travel times in space!

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Knowing Your Place: The Implications Of GPS Spoofing And Jamming

May 23, 2022 by 30 Comments

Artificial satellites have transformed the world in many ways, not only in terms of relaying communication and for observing the planet in ways previously inconceivable, but also to enable incredibly accurate navigation. A so-called global navigation satellite system (GNSS), or satnav for short, uses the data provided by satellites to pin-point a position on the surface to within a few centimeters.

The US Global Positioning System (GPS) was the first GNSS, with satellites launched in 1978, albeit only available to civilians in a degraded accuracy mode. When full accuracy GPS was released to the public under the 1990s Clinton administration, it caused a surge in the uptake of satnav by the public, from fishing boats and merchant ships, to today’s navigation using nothing but a smartphone with its built-in GPS receiver.

Even so, there is a dark side to GNSS that expands beyond its military usage of guiding cruise missiles and kin to their target. This comes in the form of jamming and spoofing GNSS signals, which can hide illicit activities from monitoring systems and disrupt or disable an enemy’s systems during a war. Along with other forms of electronic warfare (EW), disrupting GNSS signals form a potent weapon that can render the most modern avionics and drone technology useless.

With this in mind, how significant is the threat from GNSS spoofing in particular, and what are the ways that this can be detected or counteracted?

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A square PCB with a Raspberry Pi Pico mounted in the middle

Identify Radioactive Samples With This DIY Gamma-Ray Spectrometer

May 3, 2022 by 37 Comments

If you’re a radiation enthusiast, chances are you’ve got a Geiger counter lying around somewhere. While Geiger counters are useful to detect the amount of radiation present, and with a few tricks can also distinguish between the three types of radiation (alpha, beta and gamma), they are of limited use in identifying radioactive materials. For that you need a different instrument called a gamma-ray spectrometer.

Spectrometers are usually expensive and complex instruments aimed at radiation professionals. But it doesn’t have to be that way: physics enthusiast [NuclearPhoenix] has designed a hand-held gamma spectrometer that’s easy to assemble and should fit in a hobbyist budget. It outputs spectral plots that you can compare with reference data to identify specific elements.

A PCB with a sensor wrapped in black tape
The scintillator and sensor are wrapped in black tape to block out ambient light.

The heart of the device is a scintillation crystal such as thallium-doped sodium iodide which converts incoming gamma rays into visible light. The resulting flashes are detected by a silicon photomultiplier whose output is amplified and processed before being digitized by a Raspberry Pi Pico’s ADC. The Pico calculates the pulses’ spectrum and generates a plot that can be stored on its on-board flash or downloaded to a computer.

[NuclearPhoenix] wrote a convenient program to help analyze the output data and made all design files open-source. The hardest part to find will be the scintillation crystal, but they do pop up on auction sites like eBay now and then. We’ve featured an Arduino-based gamma spectrometer before; if you’ve always wanted to roll your own scintillators, you can do that too. Continue reading “Identify Radioactive Samples With This DIY Gamma-Ray Spectrometer” →

Modern Wildfires And Their Effect On The Ozone Layer

April 26, 2022 by 36 Comments

The ozone layer is a precious thing, helping protect the Earth from the harshest of the sun’s radiative output. If anything were to damage this layer, we’d all feel the results in a very short order indeed.

In the past, humanity has worked to limit damage to the ozone layer from our own intentional actions. However, it’s not just aerosol cans and damaged air conditioning systems that are putting it at risk these days. The fierce wildfires we’ve seen so much of in recent years are also having a negative effect. Let’s take a look at why the ozone layer matters, and how it’s being affected by these wildfires.

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NASA Continues Slow And Steady Pace Towards Moon

March 28, 2022 by 61 Comments

It’s often said that the wheels of government turn slowly, and perhaps nowhere is this on better display than at NASA. While it seems like every week we hear about another commercial space launch or venture, projects helmed by the national space agency are often mired by budget cuts and indecisiveness from above. It takes a lot of political will to earmark tens or even hundreds of billions of dollars on a project that could take decades to complete, and not every occupant of the White House has been willing to stake their reputation on such bold ambitions.

In 2019, when Vice President Mike Pence told a cheering crowd at the U.S. Space & Rocket Center that the White House was officially tasking NASA with returning American astronauts to the surface of the Moon by 2024, everyone knew it was an ambitious timeline. But not one without precedent. The speech was a not-so-subtle allusion to President Kennedy’s famous 1962 declaration at Rice University that America would safely land a man on the Moon before the end of the decade, a challenge NASA was able to meet with fewer than six months to spare.

Unfortunately, a rousing speech will only get you so far. Without a significant boost to the agency’s budget, progress on the new Artemis lunar program was limited. To further complicate matters, less than a year after Pence took the stage in Huntsville, there was a new President in the White House. While there was initially some concern that the Biden administration would axe the Artemis program as part of a general “house cleaning”, it was allowed to continue under newly installed NASA Administrator Bill Nelson. The original 2024 deadline, at this point all but unattainable due to delays stemming from the COVID-19 pandemic, has quietly been abandoned.

So where are we now? Is NASA in 2022 any closer to returning humanity to the Moon than they were in 2020 or even 2010? While it might not seem like it from an outsider’s perspective, a close look at some of the recent Artemis program milestones and developments show that the agency is at least moving in the right direction.

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Peltier Cloud Chamber Produces Some Lovely Trails

March 27, 2022 by 6 Comments

[Advanced Tinkering] over on YouTube has some pretty unique content, on subjects of chemistry and physics that are a little more, interesting let’s say — anyone fancy distilling cesium? The subject of this build is the visualization of ionizing radiation tracks, with one of our old favorite physics demonstrators, the venerable cloud chamber. The build video (embedded below,) shows the basic construction and performance of a Peltier effect cooler setup. The system is used to create a layer of supersaturated (and cold) alcohol vapor in which the radiation source or other experiment can be immersed.

Peltier modules are a great solution for moving heat from one surface to another, but they are not terribly efficient at it, especially if you don’t keep the hot side temperature in check. Effectively they are a short-distance heat pump, so you need to dump the hot-side heat elsewhere. The method [Advanced Tinkering] chose here was to use a pair of off-the-shelf water cooling blocks, mounted into a 3D printed plate. The hot side dumps into a pair of fan-cooled radiators. Four double-layer Peltier modules are wired in parallel to a 60A power supply, which seems like a lot, but Peltier modules are hungry little things. A reasonable amount of power is needed to drive the cooling fans and water pump. The vapor source is a simple pad of liquid alcohol at the top of the stack, just above a metal screen which is held at a high voltage. The vertical electric field allows visualization of the charge of emitted particles, which will curve up or down depending on their polarity.

As can be seen from the second video linked below, some really nice cloud trails are produced, so it looks like they got the setup just right!

Do you need all this complexity to visualize simple radiation paths? No, you don’t, but just temper your expectations. Peltier-based builds are not uncommon, here’s another one, but some builders say they’re not very robust, so this build uses phase-change technology instead for some serious runtimes.

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