The Rotary-X Engine Is A Revolution In Thermodynamics

If you’re running an army, chances are good that you need a lot of portable power for everything from communications to weapons control systems. When it comes to your generators, every ounce counts. The smaller and lighter you can get them, the better.

Connecticut-based company LiquidPiston is developing a high-powered generator for the US Army that uses the company’s own rotary x-engine — a small, light, and powerful beast that sounds like a dream come true. It can run on gasoline, diesel, natural gas, kerosene, or jet fuel, and is scalable from 1 to 1,000 horsepower (PDF).

Co-founder and CEO Alex Schkolnik describes the design as a combination of the best parts of the Otto and Atkinson cycle engines, the Diesel, and the Wankel rotary while solving the big problems of the latter two. That sounds impressive, but it doesn’t mean much unless you understand how each of these engines work and what their various advantages and disadvantages are. So let’s take a look under the hood, shall we?

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The $50 Ham: Digital Modes With WSJT-X

As it is generally practiced, ham radio is a little like going to the grocery store and striking up a conversation with everyone you bump into as you ply the aisles. Except that the grocery store is the size of the planet, and everyone brings their own shopping cart, some of which are highly modified and really expensive. And pretty much every conversation is about said carts, or about the grocery store itself.

With that admittedly iffy analogy in mind, if you’re not the kind of person who would normally strike up a conversation with someone while shopping, you might think that you’d be a poor fit for amateur radio. But just because that’s the way that most people exercise their ham radio privileges doesn’t mean it’s the only way. Exploring a few of the more popular ways to leverage the high-frequency (HF) bands and see what can be done on a limited budget, in terms of both cost of equipment as well as the amount of power used, is the focus of this installment of The $50 Ham. Welcome to the world of microphone-optional ham radio: weak-signal digital modes.

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Would You Like Fries With Your Insect Burger, Ma’am?

A trip to a supermarket is a rare luxury in a pandemic lockdown, but were I to cruise the aisles with my basket today I’d probably come away with a healthy pile of fruit and veg, a bit of meat and fish, and maybe some cheese. My shopping basket in 2031 though might have a few extras, and perhaps surprisingly some of them might be derived from insects. That’s a future made a little closer, by EU scientists declaring that farmed insect products are safe for humans and animals to eat.

Global map showing meat consumption in 2013
Is meat consumption at this level sustainable? Our World In Data, CC BY 3.0.

We humans, like some of our fellow great ape cousins, are omnivores. We can eat anything, even if we might not always want to eat some things twice. As such, the diets of individual populations would in the past have varied hugely depending on the conditions that existed wherever they lived, giving us the ability to spread to almost anywhere on the planet — and we have.

Over the past few hundred years this need to subsist only on foods locally available has been marginalized by advances in agriculture. For those of us in developed countries, any foodstuff that takes our fancy can be ours for a trivial effort. This has meant an explosion of meat consumption as what was once a luxury food has become affordable to the masses, and in turn a corresponding agricultural expansion to meet demand that has placed intolerable stresses on ecosystems and is contributing significantly to global warming. It’s very clear that a mass conversion to veganism is unlikely to take place, so could farmed insects be the answer to our cravings for meat protein? It’s likely to be a tough sell to consumers, but it’s a subject that bears more examination. Continue reading “Would You Like Fries With Your Insect Burger, Ma’am?”

The Modding, Restoration, And Demise Of A $3M Analog Computer

How do you rapidly record the output from your three million dollar analog computer in the 1940s when the results are only available on analog meters? The team responsible for the Westinghouse 1947 AC Network Calculator at Georgia Tech was faced with just this problem and came up with a nifty solution — hack the control panel and wire in a special-purpose drafting table.

What Is It?

What is this beast of a computer? Machines of this type were developed during and after World War 2, and strictly speaking, belong in the category of scale models rather than true computers. Although these machines were very flexible, they were primarily designed to simulate power distribution grids. There is a lot of theory under the hood, but basically a real world, multi-phase distribution system would be scaled to single-phase at 400 Hz for modeling.

The engineers would “program” the machine by connecting together the appropriate circuit elements (like capacitors, inductors, transmission lines, generators, etc.) on big patch panels. Thus programmed, a 10 kW motor-generator located in the basement would be started up and the simulation was underway. Continue reading “The Modding, Restoration, And Demise Of A $3M Analog Computer”

Getting Ready For Mars: The Seven Minutes Of Terror

For the past seven months, NASA’s newest Mars rover has been closing in on its final destination. As Perseverance eats up the distance and heads for the point in space that Mars will occupy on February 18, 2021, the rover has been more or less idle. Tucked safely into its aeroshell, we’ve heard little from the lonely space traveler lately, except for a single audio clip of the whirring of its cooling pumps.

Its placid journey across interplanetary space stands in marked contrast to what lies just ahead of it. Like its cousin and predecessor Curiosity, Perseverance has to successfully negotiate a gauntlet of orbital and aerodynamic challenges, and do so without any human intervention. NASA mission planners call it the Seven Minutes of Terror, since the whole process will take just over 400 seconds from the time it encounters the first wisps of the Martian atmosphere to when the rover is safely on the ground within Jezero Crater.

For that to happen, and for the two-billion-dollar mission to even have a chance at fulfilling its primary objective of searching for signs of ancient Martian life, every system on the spacecraft has to operate perfectly. It’s a complicated, high-energy ballet with high stakes, so it’s worth taking a look at the Seven Minutes of Terror, and what exactly will be happening, in detail.

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Sewage Maceration Is As Gross As It Sounds

Day to day, few of us really contemplate what’s happening on a deep, mechanical level when we use the toilet. The business is done, the toilet is flushed, and we go about our day. However, the magnificent technology of indoor sanitation should not be sniffed at, given the manner in which it facilitates a cleaner, more comfortable existence for us all.

The vast majority of flush toilets rely on the benefit of gravity to remove waste from the house. This necessitates that the toilet be installed above the sewage lines that exit the house. For most installations at ground floor and above, this isn’t a problem. However, on occasions you may encounter basements or houses with rooms at lower levels where a regular toilet simply won’t work. Obviously, a pump is in order, but human sewage being a mixture of liquids and solids makes this impractical. Instead, it must be turned into a slurry that can be pumped; a process known as sewage maceration. Buckle up!

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Machine Learning In The Kitchen Makes For Tasty Mashup Desserts

What did you do during lockdown? A whole lot of people turned to baking in between trips to the store to search for toilet paper and hand sanitizer. Many of them baked bread for some reason, but like us, [Sara Robinson] turned to sweeter stuff to get through it.

The first Cakie ever made. Image via Google Cloud

Her pandemic ponderings wandered into the realm of baking existentialist questions, like what separates baked goods from each other, categorically speaking? What is the science behind the crunchiness of cookies, the sponginess of cake, and the fluffiness of bread?

As a developer advocate for Google Cloud, [Sara] turned to machine learning to figure out why the cookie crumbles. She collected 33 recipes each of cookies, cake, and bread and built a TensorFlow model to analyze them, which resulted in a cookie/cake/bread lineage for each recipe in a set of percentages. Not only was the model able to accurately classify recipes by type, [Sara] was able to use the model to come up with a 50/50 cookie-cake hybrid recipe. The AI delivered a list of ingredients to which she added vanilla extract and chocolate chips for flavor. From there, she had to wing it and come up with her own baking directions for the Cakie.

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