Creating An Automated Hydrogen Generator At Home

October 6, 2023 by Maya Posch 34 Comments

Everyone and their pet hamster probably knows that the most common way to produce hydrogen is via the electrolysis of water, but there are still a number of steps between this elementary knowledge and implementing a (mostly) automated hydrogen generator. Especially if your end goal is to create liquid hydrogen when everything is said and done. This is where [Hyperspace Pirate]’s latest absolutely not dangerous project commences, with the details covered in the recently published video.

Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]'s dog drinking bowl. — Automated hydrogen generator setup, courtesy of [Hyperspace Pirate]’s dog drinking bowl.

Since electrolysis cannot occur with pure water, sodium hydroxide (NaOH) is used in the solution to provide the ions. The electrodes are made of 316 stainless steel, mostly because this is cheap and good enough for this purpose. Although the original plan was to use a stacked series of electrodes with permeable membranes like in commercial electrolysers, this proved to be too much of a hassle to seal up leak-tight. Ergo the demonstrated version was attempted, where an upturned glass bell provides the barrier for the produced hydrogen and oxygen. With this system it’s easy to measure the volume of the produced hydrogen due to the displaced water in the bell.

Once enough hydrogen gas is produced, a vacuum pump is triggered by a simple pair of electrodes to move the hydrogen gas to a storage container. Due to hydrogen embrittlement concerns, an aluminium tank was used rather than a steel one. Ultimately enough hydrogen gas was collected to fill a lot of party balloons, and with the provided information in the video it should be quite straightforward to reproduce the system.

Where the automation comes into play is with a control system that monitors for example how long the vacuum pump has been running, and triggers a fail safe state if it’s more than a set limit. With the control system in place, [Hyperspace Pirate] was able to leave the hydrogen generator running for hours with no concerns. We’re hopeful that his upcoming effort to liquify this hydrogen will be as successful, or the human-rated blimp, or whatever all this hydrogen will be used for.

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Bleep Remover Censors Those **** Bleeps

October 4, 2023 by Maya Posch 20 Comments

One of the more interesting cultural phenomena is the ‘bleep’ that replaces certain words in broadcasts, something primarily observed in the US. Although ostensibly applied to prevent susceptible minds from being exposed to the unspeakable horrors of naughty words, the applied 1 kHz censoring tone is decidedly loud and obnoxious enough that its entertainment level falls somewhere between ‘truck backing up’ and ‘loud claxon in busy traffic’. There is thus a definite argument to be made to censor the censoring beep to preserve one’s sanity, which is the goal of [Oona Räisänen]’s Bleep-be-gone project on GitHub.

Using a Perl-based wrapper, the versatile ffmpeg framework is used to filter a provided video that was afflicted with bleepitus, before outputting a pristine version where the infernal noise is replaced with blissful silence. This use of silence for censoring naughty words is incidentally becoming more commonplace over an ear-piercing beep, but a tool like Bleep-be-gone can be used to hasten the demise of its terror. Considering that the point of the 1 kHz back-up alarm beep is to draw a person’s attention to a piece of heavy equipment moving about, there is clearly no good reason why the replacement of a naughty word should warrant a similar drawing of attention.

ARPA-H Moonshot Project Aims To Enable 3D Printing Of Human Organs

October 4, 2023 by Maya Posch 9 Comments

The field of therapeutic cloning has long sought to provide a way to create replacement organs and tissues from a patient’s own cells, with the most recent boost coming from the US Advanced Research Projects Agency for Health (ARPA-H) and a large federal contract awarded to Stanford University.

Patients on the organ donation waiting list in the US (Source: HRSA)

The creatively named Health Enabling Advancements through Regenerative Tissue Printing (HEART) project entails a 26.3 million USD grant that will be used to create a functioning bioprinter backed by a bank of bioreactors. Each bioreactor will cultivate a specific type of cell, which will then be ‘printed’ in its proper place to gradually build up the target organ or tissue. The project’s five year goal is the printing of a fully functioning human heart and implanting it into a pig.

Assuming this is successful, the general procedure can then be refined to allow for testing with human patients, as well as the bioprinting of not just hearts, but also lungs, kidneys and much more. The lead investigator at Stanford University, [Mark Skylar-Scott], cautions that use with human patients is likely to be still decades off. But the lifesaving potential of this technology, once matured, is staggering. This is highlighted by data from the US HRSA, with over 42,000 transplants in 2022 in the US alone, with over a hundred-thousand patients waiting and 17 people who die each day before an organ becomes available.

Bioadhesive Polymer Semiconductors For In-Vivo Sensors

October 3, 2023 by Maya Posch 2 Comments

What do you do when you want to stick an electrode or even an couple of sensors to an internal organ, such as a heart? Generally you’d use some kind of special adhesive, or sutures to ensure that the item remains firmly in place and doesn’t migrate to somewhere else within the chest cavity or among the intestines. According to a new study (press release) by Nan Li and colleagues in Science there may however be a more elegant method, using bioadhesive polymers.

The double-network copolymer is designed so that once put in the desired location it soaks up moisture and provides a dry interface for its bioadhesive properties. In addition, the resulting material is electrically conductive, with a measured charge-carrier mobility of ~1 square centimeter per volt per second.

Using thus manufactured electrodes were applied to both an isolated rat heart and in vivo rat muscles to measure electrical currents produced by each respective tissue type. The authors of the study envision that using this technology more complicated interfaces and sensors can be developed that would interface directly with organs and related. The claimed biocompatibility would also allow for such devices to be left in-situ for extended periods of time, which could be a boon for a wide range of medical conditions where continuous monitoring is a crucial element.

Metamaterial Enables Topological Pumping Of Elastic Surface Waves

October 3, 2023 by Maya Posch 3 Comments

Although it is generally assumed that surface elastic waves (vibrations) — such as those of earthquakes — will travel mostly unimpeded until their energy dissipates, there are ways to ‘steer’ this energy using metamaterials.

Time response of the topological surface wave transport.(A to C). The magnitude of total displacement field at 0.5 ms, 2.5 ms, and 4 ms, respectively. A 50-cycle tone burst signal centered at 41.88 kHz is simulated on the bottom supercell. (Wang et al., 2023) — Time response of the topological surface wave transport.
(A to C). The magnitude of total displacement field at 0.5 ms, 2.5 ms, and 4 ms, respectively. A 50-cycle tone burst signal centered at 41.88 kHz is simulated on the bottom supercell. (Wang et al., 2023)

A recent study by [Shaoyun Wang] and colleagues in Science Advances details how a carefully modelled grouping of columns creates what is termed a synthetic dimension. In their experimental setup, it is demonstrated how an applied wave is guided across the metamaterial, rather than spreading out the way which we would expect to see in conventional materials.

Interestingly, in the paper it is also demonstrated how the same technique can be used to create a wave-splitter that diverts the wave energy in two distinct directions. Due to the innate resistance of this type of structure to defects, manufacturing it is not too complicated.

In this experiment the metamaterials were milled out of a block of aluminium on a CNC mill, which makes it seem eminently realistic that it could be scaled up and translated to other applications. Conceivably annoyances like vibrations from road traffic and heavy machinery, all the way up to the destructive energies of earthquakes could one day be reduced, redirected or even extinguished using structures as demonstrated here.

Femtosecond Laser Clones Itself In Glass

October 3, 2023 by Maya Posch 4 Comments

When researchers at the Galatea laboratory in Switzerland set out to create a femtosecond laser in glass they weren’t certain it was going to work. To be precise, their goal was to create a femtosecond laser cavity using carefully aligned optics. Rather than using the traditional, discrete method, they used a commercial femtosecond laser to carve out the elements of the optical cavity in glass. The choice for glass came down to the low thermal expansion of this material, and it being transparent for the optical frequencies being targeted.

Generic concept of an “all-glass” optical device, with the various stages of fabrication. (Credit: Antoine Delgoffe et al., 2023)

Even after using the existing laser to create the rough laser cavity, the resulting optical mirrors were not aligned properly, but this was all part of the plan.

By also adding slots that created a flexure mechanism, brief laser pulses could be used to gradually adjust the mirrors to create the perfect alignment. During subsequent testing of the newly created laser cavity it was found to be operating as expected. The original femtosecond laser had successfully created a new femtosecond laser.

Perhaps the most tantalizing aspect of this research is that this could enable much faster and ultimately cheaper production of such laser systems, especially once the tedious and currently completely manual mirror alignment procedure is automated. In addition, it raises the prospect of producing other types of optics including splitters and guides in a similar manner.

The Path To Profiling Extraterrestrial Atmospheres With Astrophotonics

October 2, 2023 by Maya Posch 6 Comments

A major part of finding extraterrestrial life is to be able to profile the atmosphere of any planets outside of our solar system. This is not an easy task, as these planets are usually found through the slight darkening of their star as they pass in front of it (transition). Although spectroscopy is the ideal way to profile the chemical composure of such a planet, having a massive, extremely bright star right next to the planet is more than enough to completely overpower the faint light reflecting off the planet’s surface and through its atmosphere. This is a major issue that the upcoming Habitable Exoplanet Imaging Mission (HabEx, also called the Habitable Worlds Observatory, or HWO) hopes to address using a range of technologies, including a coronagraph that should block out most of the stellar glare.

While this solves much of the issue, there are still a range of issues which the new field of astrophotonics seeks to address, as detailed in a recent paper by Nemanja Jovanovic and colleagues. This involves not only profiling chemical compositions, but also increasing the precision when monitoring for planet transit events using e.g. semiconductors-based laser frequency combs. These are generally combined with a spectral flattener, which in experimental on-chip form are significantly less bulky than previous setups, to the point where they don’t necessarily have to be Earth-based.

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