Retrotechtacular: Firepower For Freedom

As the United States were settled, its leaders found that they needed firepower to preserve freedom. This became especially apparent during the military engagements of the era, so a number of specialized facilities were founded to manage the research, development, manufacture, and dissemination of different types of munitions.

Picatinny Arsenal in New Jersey was the place for both nuclear and conventional weapon development. The men and women working in this facility created anti-personnel devices, including a flexible, adhesive charge called Flex-X that could be affixed to almost anything. This demolition charge could be layered for increased power, and could even detonate underwater. Picatinny also developed new rocket engines, propellants, and liquid propulsion for projectiles.

In Pennsylvania, a small-arms ammunition plant called Frankford Arsenal developed a duplex rifle cartridge. That is, a lead projectile fires on target, and a second one sitting behind it in the cartridge shoots at an angle, landing an inch or so near the lead bullet. Frankford workers also ground precision optics for target sighting and centering, and developed a case-less cartridge. Propellants geared for a wide variety of uses also came out of Frankford. These propellants were employed to deliver nerve agent antidotes, inflate life rafts quickly, and eject pilots from sketchy situations.

The Edgewood Arsenal in Baltimore specializes in the research and development, manufacture, and supply of chemical weapons. They are particularly adept at fire suppression. Edgewood research has provided civilian benefits as well, such as an anthrax vaccine. In addition, Fort Detrick, Maryland contains a biological R&D wing where vital antidotes and vaccines are developed.

All of this R&D and manufacture was orchestrated by the Ammunition Procurement and Supply Agency (APSA) located near Joliet, IL. In addition to reviewing all contractor bids with equal consideration, APSA controlled distribution, maintaining inventory on large computers that could crunch numbers like nobody’s business.

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Not Just a Floor Wax but an Embossing Powder!

The embossing process used in the creation of some of your fancier wedding invitations and business cards is an interesting one. It’s often called thermography or thermographic printing. Slow-drying, wet ink is applied to a substrate. The ink is dusted with a thermoplastic polymer called embossing powder, and a heat source raises the ink while drying it.

Commercial embossing powder costs about $10 an ounce. As [Ken] discovered, its manufacture is quite closed-source to boot. He set about creating his own embossing powder, and succeeded with a combination of commonly available floor finish and distilled white vinegar. A standard-sized bottle of floor finish yielded about four ounces of homemade embossing powder.

How does this work? The floor finish is an acrylic-based stable emulsion. Adding vinegar destabilizes the emulsion, decreasing its pH and setting the polymer free.  It’s a fairly fast process, which you can see in the second video that accompanies [Ken]’s write up. From there, it’s mostly a matter of straining the material, letting it dry, and pulverizing the coarse matter into powder. In the first video, [Ken] performs a comparison test of Ranger, a commercial powder, and his own concoction.

For a completely different take on home embossing, check out this soda-can-turned-keepsake-box.

Retrotechtacular: Gone Fission

This week’s film begins as abruptly as the Atomic Age itself, though it wasn’t produced by General Electric until 1952. No time is wasted in getting to the point of the thing, which is to explain the frightening force of nuclear physics clearly and simply through friendly animations.

[Dr. Atom] from the Bohr Modeling Agency describes what’s going on in his head—the elementary physics of protons, neutrons, and electrons. He explains that atoms can be categorized into families, with uranium weighing in as the heaviest element at the time. While most atoms are stable, some, like radium, are radioactive. This evidently means it stays up all night doing the Charleston and throwing off neutrons and protons in the process of jumping between atomic families. [Dr. Atom] calls this behavior natural transmutation.

Artificial transmutation became a thing in the 1930s after scientists converted nitrogen into oxygen. After a couple of celebratory beers, they decided to fire a neutron at a uranium nucleus just to see what happened. The result is known as nuclear fission. This experiment revealed more about the binding force present in nuclei and the chain reaction of atomic explosions that takes place. It seemed only natural to weaponize this technology. But under the right conditions, a reactor pile made from graphite blocks interspersed with U-235 and -238 rods is a powerful and effective source of energy. Furthermore, radioactive isotopes have advanced the fields of agriculture, industry, medicine, and biochemistry.

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Arduino-Based Dispenser Delivers Liquids, Powders

If you like to cook or bake, you probably don’t measure everything out in little bowls and ramekins before you start. Well,unless you also happen to like doing dishes. Even so, there are a lot of measuring spoons and -cups that end up getting dirty in the process. But what if you had a measuring machine to dole out spices and low-viscosity liquids in specific quantities for you?

[enddev]’s creation is based around an Arduino Mega, and the interface is three buttons and an LCD. The user selects between liquid and powder, followed by the desired measurement. If liquid is chosen, the peristaltic pump is engaged to deliver the specified amount through silicone tubing. The current powder setup uses a kitchen scale, which the designers found to be inaccurate for small amounts. They believe that a volume auger and stepper motor would be ideal.

The team mentions that the powder delivery system is better suited for flakier substances since it’s basically agitated out of the container. This makes us think this would be great for feeding fish. If you take this admirably-written Instructable and use it to feed your fish or something, let us know. Their code is on the gits.

[via Embedded Lab]

Retrotechtacular: The Spirit of Radio

Many of us still tune in to terrestrial radio for one reason or another, be it baseball games, talk radio, or classic rock. But do you know how the sound is transmitted to your receiver? This week, our spotlight shines upon a short film produced by KYW Radio that serves as a cheerful introduction to the mysteries of amplitude modulation (AM) radio transmission as they were in 1940.

Sound vibrations enter a microphone and are converted to electrical current, or an audio waveform. The wave is amplified and sent several miles away to the transmitting station. During this trip, the signal loses power and so is amplified at the transmitting station in several stages. This audio wave can’t be transmitted by itself, though; it needs to catch a ride on a high-frequency carrier wave. This wave is generated on-site with a huge crystal oscillator, then subjected to its own series of amplifications prior to broadcast.

The final step is the amplitude modulation itself. Here, the changing amplitude of the original audio wave is used to modulate that of the high-frequency carrier wave. Now the signal is ready to be sent to the tower. Any receiver tuned in to the carrier frequency and in range of the signal will capture the carrier wave. Within the reciever, these currents are converted back to the vibrations that our ears know and love.

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Using The Sun To Beat The Heat

It’s practically May, and that means the sweltering heat of summer is nearly upon us. Soon you’ll be sitting outside somewhere, perhaps by a lake, or fishing from a canoe, or atop a blanket spread out on the grass at a music festival, all the while wishing you had built yourself a solar-powered personal air conditioner.

[Nords] created his from a large insulated beverage vessel. The imbibing spout offers a pre-made path to the depths of said vessel and the heart of this build, the ice water refrigerant. [Nords] fashioned a coil out of copper tubing to use as a heat exchanger and strapped it to the fan that performed best in a noise-benefit analysis.

A small USB-powered submersible pump moves the ice water up through the copper tubing. Both the pump and the fan run off of a 5V solar panel and are connected with a USB Y cable, eliminating the need for soldering. Even if you spend the summer inside, you could still find yourself uncomfortably warm. Provided you have access to ice, you could make this really cool desktop air conditioner.

[via Embedded Lab]

Retrotechtacular: Radar Jamming

It’s been said that the best defense is a good offense. When aloft and en route to deliver a harmful payload to the enemy, the best defense is to plan your approach and your exit carefully, and to interfere with their methods of detection. If they can’t find you, they can’t shoot you.

As of May 1962, the United States military was using three major classifications of radar jamming technology as described in this week’s film: the AN/ALQ-35 multiple target repeater, the AN/ALQ-55 communications link disrupter, and the AN/ALQ-41 and -51 track breakers. The most important role of these pieces of equipment is to buy time, a precious resource in all kinds of warfare.

The AN/ALQ-35 target repeater consists of a tuner, pulse generator, transmitter, and control panel working in concert to display multiple false positives on the enemy’s PPI scopes. The unit receives the incoming enemy pulse, amplifies it greatly, repeats it, and sends them back with random delays.

The AN/ALQ-55 comm disrupter operates in the 100-210MHz band. It distinguishes the threatening enemy communication bands from those of beacons and civilians, evaluates them, and jams them with a signal that’s non-continuous, which helps avoid detection.

Finally, the AN/ALQ-41 and -51 track breakers are designed to break enemy lock-on and to give false information. It provides simultaneous protection against pulse ranging, FM-CW, conical, and monopulse radar in different ways, based on each method’s angle and range.

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