This is where the drones came in

Monday, November 30th, 2020

Before the war, on a tactical level the Armenian army was superior to the Azeri army:

It had better officers, more motivated soldiers, and a more agile leadership. In all previous wars with Azerbaijan, this proved to be decisive. But Azerbaijan found a way to work around it. This is where the drones came in: they allowed the Azeris to reconnoitre first the Armenian position and then the placement of reserves. Armenian positions then could be extensively shelled with conventional artillery, weakening their defences. Drones then guided the onslaught towards the Armenian reserves, bringing in artillery, multiple-rocket systems with cluster munitions, their own missiles, or using Israeli-made LORA ballistic missiles to destroy bridges or roads linking the reserves with the front. Once the Armenian side was incapable of sending reserves into battle, the Azeri army could move in any number it wished to overwhelm the isolated Armenian positions. This procedure was repeated day after day, chipping one Armenian position away each day and resupplying artillery during the night.

This tactic also worked well in mountainous territory the Armenians thought would be easy to defend. In the mountains, there is only one road connecting the front to the rear, which made it even easier for drones to spot targets. When the battle over Shusha demonstrated that the Armenians would not stand a chance even in this territory, the Armenian army started to disintegrate and Yerevan had no choice than to agree a ceasefire on adverse terms.

Plot-fusion is essential to detecting small and low-observable targets such as advanced drones or stealth aircraft

Saturday, November 28th, 2020

One of the military lessons from Nagorno-Karabakh is that computers and networks matter:

Like in Syria and Libya, Russian air-defence systems proved to be ineffective against small and slow drones. This has inspired a debate in the West about whether Russian air-defence systems are generally overrated. But this verdict would be premature.

Armenia’s most ‘modern’ air-defence systems, the S-300PT and PS series and the 9K37M Buk-M1, were both developed in the 1980s. While the missiles are still potent, their sensors are designed to detect, identifiy and track fast-moving fighters, and their moving-target indicators disregard small, slow drones. Like many 1980s systems, a lot of computing is predetermined by hardware layout, and reprogramming requires an extensive refit of the entire system, which the Armenians had not done. These systems are also incapable of plot-fusion: accumulating and combining raw radar echoes from different radars into one aggregated situation report. Plot-fusion is essential to detecting small and low-observable targets such as advanced drones or stealth aircraft. None of the export versions of Russia’s air-defence systems that it has sold to Syria, Turkey, North Korea, and Iran are capable of plot-fusion. (In the latter two cases, these are disguised as ‘indigenous’ systems like the Raad or Bavar 373.) There is therefore a huge difference in performance between Russian air-defence systems protecting Russian bases in Armenia and Syria and those Russian air-defence systems exported to Armenia and Syria.

Azerbaijan’s drones roamed free because Armenia had no jammer able to interrupt the signals linking the drones to their guidance stations. Only in the last days of the war did Russia use the Krasukha electronic warfare system based at the Armenian city of Gyumri to interdict Azeri deep reconnaissance in Armenia proper. Still, the Azeris also used the Israeli Harop loitering munition, which was able to work under adverse conditions (although at reduced effectiveness) as it does not, unlike drones. require a guidance link. Hence among armies that are likely to prepare to fight wars in the future – not only the US, China, Russia but regional powers such as Turkey, Israel, and South Africa – this experience will certainly prompt further research into artificial intelligence and autonomous lethal weapons systems. Rather than banning this class of ammunition by a prohibitive arms control treaty, as envisioned by Europe, they will experiment with how to make use of the new technologies and best integrate autonomous lethal weapons systems into their combined-arms manoeuvre forces, thereby increasing their operational tempo and effectiveness.

The information war has been just as fierce as the actual war

Thursday, November 19th, 2020

The information war has been just as fierce as the actual war in Nagorno-Karabakh, with both sides posting daily combat footage to proclaim victories:

Disinformation and propaganda, spread through official and unofficial accounts, have made it difficult to objectively assess the course of combat thus far. Furthermore, the relative accessibility of combat footage — whether from drones, cellphones, or cameras — paints a stylized picture of the battlefield for any analyst. They are official propaganda, and it is worth noting that on the modern battlefield, some systems have cameras or live video feeds, while many do not, distorting perceptions on combat effectiveness. A social media feed composed largely of drone video footage could lead one to believe in the dominance of such systems, even in a conflict where many casualties are still inflicted by armor, artillery, and multiple launch rocket systems. This tactical footage has led to familiar debates on the utility of tanks, the prowess of drones on the battlefield, or the proliferation of sensors.

There is a thirst for drawing lessons from contemporary conflicts that feature modern weapon systems. However, the result is often generalizing from a few cases, and at times, learning things that are not true. What can be discerned from this war is hardly revelatory. Remotely operated systems offer the utility of tactical aviation, close air support, and precision guided weapons to small nations, and to even relatively poor countries, for a cheap price. They saturate the battlefield with disposable sensors, shooters, and sensor-shooter packages in the form of loitering munitions. Notably, they enable precision artillery and strike systems to engage fixed positions, as has been seen across modern conflicts from Ukraine to Syria. Furthermore, tanks are vulnerable to counters, as they always have been, but it is unclear what other vehicles offer a better combination of firepower, protection, and maneuverability on the battlefield.

The war illustrates that in an offensive, or counter-offensive, the only thing worse than being in a heavily armored vehicle is being outside of one. If anything, the tank appears to be the most survivable vehicle, given the small warheads on drone carried munitions. These munitions often disable or mission kill the vehicle, but the crew can still survive anything other than a direct hit. Much of the hand-wringing in Western circles that comes from watching these conflicts stems from the epiphany that there is no way to avoid casualties on the modern battlefield, especially among an expensive force, replete with boutique capabilities that cannot be lost in large quantities. Furthermore, the ratios of support to maneuver units are important. Compared to forces like the Russian military, Western ground units feature poor availability of air defense and electronic warfare, and the expectations that existing air defenses or tactical aviation may be easily adapted to counter unmanned systems are probably unfounded. Armenia’s performance illustrates this problem. Drones are relatively cheap, and this military technology is diffusing much faster than cost-effective air defense or electronic warfare suitable to countering them.

That said, Azerbaijan’s unmanned air force has been operating against an opponent with incredibly dated short-range air defenses which are neither suitable nor effectively employed to defend against drones. Armenia does not have layered air defense, effective electronic warfare, or a large amount of tactical aviation. It has situated its air defense systems in relatively exposed fixed positions, in a mountainous region where air defense is even more difficult by virtue of the terrain. In truth, both sides are demonstrating tactical deficiency in their offensive and defensive tactics. While attaining some kills using optical sights, Armenia’s modernized Soviet systems (essentially technology that dates back to the early 1970s) were never meant to engage combinations of small drones, loitering munitions, precision artillery, or unmanned combat aerial vehicle systems. More advanced air defense capabilities like Tor-M2s are few, and have been intentionally held in reserve, although Azerbaijan has been reticent to use its fixed wing or rotary aviation. Armenia’s older S-300PS systems appear to have had no role in the conflict, and some launchers may have been destroyed early on, having never even been deployed.

The lessons from this conflict are consistent with those of other wars in the latter 20th century: It is much better to have a smaller ground force that is well defended from the air, than a vast armored force that is completely exposed to sensors and airpower from above. Well prepared defenses, if insufficiently protected or camouflaged from the air — which is increasingly difficult — are naturally vulnerable. The diffusion of remotely operated systems will outpace that of air defenses or specialized counter-drone systems, rendering older generations of air defense largely obsolete. Drones and loitering munitions will be, for some time, cheaper to acquire than the requisite defenses. And one can distribute forces, but they should be concentrated for assaults. There is no way getting around canalizing terrain, at least not until the battlefield features hover tanks. That tanks are vulnerable to anti-tank weapons should come as no surprise, but other vehicles, which trade survivability for maneuverability, seem to fare no better against anti-tank guided missiles. Vulnerable or not, it is unclear what other vehicle can achieve the tank’s mission on the battlefield.

Any conflict in space will be much slower and more deliberate than a Star Wars scene

Saturday, November 14th, 2020

When considering how to control space , Rebecca Reesman and James Wilson lay out the ways in which space combat is counter-intuitive for policymakers and strategists:

Satellites move quickly, but predictably:  Satellites in commonly used circular orbits move at speeds between 3km/s and 8km/s, depending on their altitude. By contrast, an average bullet only travels about 0.75km/s. They are here, and then gone.

Space is big: The volume of space between low-earth orbit and geostationary orbit is about 200 trillion cubic kilometers. That is 190 times larger than the volume of Earth.

Timing is everything: Within the confines of the atmosphere, airplanes, tanks, and ships can nominally move in any direction. Satellites do not have that freedom. Due to the gravitational pull of Earth, satellites are always moving in either a circular or elliptical path, constantly in free-fall around the Earth. Getting two satellites in the same spot is not intuitive. Therefore, it requires careful planning and perfect timing.

Satellites maneuver slowly: While satellites move quickly, space is big, and that makes purposeful maneuvers seem relatively slow. Once a satellite is in orbit, it requires time and a large amount of delta-V to perform phasing maneuvers.

Given all of this, for engagements in space, maneuvers and actions will have to be planned far in advance, Reesman said in an interview. “Any conflict in space will be much slower and more deliberate than a Star Wars scene,” she said. “It requires a lot more long-term thinking and strategic placement of assets.

[...]

Radio signals can be used to jam an opponent’s satellites, or spoof them by sending harmful commands. This would be an extension of electronic warfare already used in naval and air battles.

Some nations, such as France, have gone so far as to talk about deploying weapons in space to protect their own satellites. However, the authors suggest that satellites using kinetic weapons to shoot down opposing satellites seems unlikely for now, given the extraordinary energy required to maneuver an orbital weapon into a proper trajectory. More likely would be a “T-bone” collision between satellites, which does not require plane matching but rather occurs when two orbits cross.

Nations do have a strong incentive to not destroy other satellites because of the potential to create hazardous debris that would potentially affect all nations’ assets in space—and debris generated in space has a lasting effect. However, in the immediacy of war, a nation may decide it is worth permanently losing access to some slots in geostationary orbit, due to debris, in order to win a ground-based war.

The Army wants the first casualty of the next war to be a robot, not a human being

Thursday, November 12th, 2020

The Army wants the first casualty of the next war to be a robot, not a human being:

Army studies of recent conflicts — Russia vs. Ukraine, Armenia vs. Azerbaijan — show you can have a dramatic impact by adding a small infusion of 21st century tech to a largely Cold War force, [Maj. Gen. Patrick] Donahoe said. How? One approach the Russians have employed to devastating effect is to use drones to spot targets for rocket launchers. Likewise, while the US Army is developing a host of new missiles, armored vehicles, and aircraft, most units will be using Reagan-era hardware for years to come. In essence, Donahoe wants to organize these existing weapons in new formations and add drones and ground robots to scout ahead.

[...]

Historical data on direct-fire engagements “shows that our enemies generally shoot first 80 percent of the time,” Sando said. “We don’t like those odds, [so] we want to avoid the close fight if we can. If we can’t avoid it, we want to enter it under conditions that are favorable to us.”

But how? Current Army doctrine prescribes “making contact with the smallest element.” In layman’s terms, if you must stumble upon the enemy and get shot at (the formal term for this is a, “meeting engagement”), then do it with the smallest vanguard possible, giving the main body time to prepare and maneuver without being pinned down. In the future, Donahoe said, the goal will be to make first contact with an unmanned element.

Cold War doctrine envisioned engaging the enemy along what’s called the Forward Line Of Troops, or FLOT. In the new concept, according to a briefing at the conference, a Forward Line Of Unmanned Aerial Systems (FLUA) will fly ahead through no-man’s-land into enemy-held territory, followed by a Forward Line Of Robots (FLOR) on the ground, followed in turn by the Forward Line Of (Human) Troops. The unmanned systems will flush out the enemy, stumble into meeting engagements and ambushes, take and receive the first hits, and map the enemy position for the human troops coming along behind them.

Of course, the Army can’t do this today. To execute the concept in reality, they need a lot more unmanned systems, so they’re going to build them.

The sails will be made of steel and composite materials

Friday, November 6th, 2020

The Oceanbird transatlantic car carrier being designed by Swedish shipbuilder Wallenius Marine will be the world’s largest wind-powered vessel:

With capacity for 7,000 vehicles, the 650 foot-long vessel is a similar size to conventional car carriers, but it will look radically different. The ship’s hull is topped by five telescopic “wing sails,” each 260 feet tall. Capable of rotating 360 degrees without touching each other, the sails can be retracted to 195 feet in order to clear bridges or withstand rough weather.

The sails, which will be made of steel and composite materials, need to be this size to generate enough propulsive power for the 35,000-ton ship.

Although “the general principles of solid wing sails is not new,” designing the Oceanbird’s sails has been a challenge, says Mikael Razola, a naval architect and research project manager for Oceanbird at Wallenius Marine.

That’s because these are the tallest ship sails that have ever been constructed. “This ship, at the top of the mast, will be more than 100 meters (328 feet) above the water surface,” says Razola. “When you move up into the sky that much, wind direction and velocity change quite a lot.”

To better understand the atmospheric conditions at this height, Wallenius mounted sensors on top of its existing vessels, while they were crossing the Atlantic, and gathered data on wind velocity and veer (a clockwise change in wind direction), up to 650 feet above sea level. “All of this information has helped us design an efficient wing and hull system, that can make the most of the power available in the wind,” says Razola.

Oceanbird Car-Carrier

It won’t be completely emission-free, however, because it will still rely on engines for manoeuvring in and out of ports and for emergencies.

With a projected top speed of about 10 knots, Oceanbird will be slower than standard car carriers, which can travel at 17 knots. It will take around 12 days, instead of the standard seven, to cross the Atlantic.

NDB uses graphite nuclear reactor parts that have absorbed radiation from nuclear fuel rods and have themselves become radioactive

Thursday, September 10th, 2020

Nano-diamond self-charging batteries could disrupt energy as we know it;

NDB uses graphite nuclear reactor parts that have absorbed radiation from nuclear fuel rods and have themselves become radioactive. Untreated, it’s high-grade nuclear waste: dangerous, difficult and expensive to store, with a very long half-life.

This graphite is rich in the carbon-14 radioisotope, which undergoes beta decay into nitrogen, releasing an anti-neutrino and a beta decay electron in the process. NDB takes this graphite, purifies it and uses it to create tiny carbon-14 diamonds. The diamond structure acts as a semiconductor and heat sink, collecting the charge and transporting it out. Completely encasing the radioactive carbon-14 diamond is a layer of cheap, non-radioactive, lab-created carbon-12 diamond, which contains the energetic particles, prevents radiation leaks and acts as a super-hard protective and tamper-proof layer.

To create a battery cell, several layers of this nano-diamond material are stacked up and stored with a tiny integrated circuit board and a small supercapacitor to collect, store and instantly distribute the charge. NDB says it’ll conform to any shape or standard, including AA, AAA, 18650, 2170 or all manner of custom sizes.

(Hat tip to Hans G. Schantz.)

You used to be able to fly into a country on one name and have meetings in another

Monday, August 31st, 2020

Modern technology is putting an end to traditional spying:

The beginning of the CIA’s cover and tradecraft crisis dates back to at least February 2003, when a Muslim cleric known as Abu Omar disappeared off the street in Milan. He didn’t resurface until 2004, when he called his wife from Cairo to tell her about his kidnapping, detention and torture at the hands of the CIA.

Italian investigators, eager to get to the bottom of the audacious abduction on their streets, were later able to track a web of cellphones communicating only with each other in close proximity to the disappearance, leading them to a series of hotel bills, credit card statements and other identifying indicators, according to a 2007 investigation unveiled at an annual hacker conference in 2013. Italian authorities charged 23 Americans, including the CIA’s former Milan station chief, for their roles in the scheme — most in absentia.

While Omar was just one target of the CIA’s aggressive post-9/11 antiterrorism campaign, several former intelligence officials described the Milan operation’s aftermath as a “come to Jesus” moment that revealed just how vulnerable the agency’s operators were to technology. At the time, some undercover officials naively believed that methods like using potato chip bags would mask cellphone signals, and operatives were generally “freewheeling,” according to one former senior intelligence official. In the space of a few short years, the rapid advance of technology, including nascent international surveillance systems, increasingly endangered the CIA’s traditional human intelligence gathering.

Singapore was one example, recall three former intelligence officials. By the early 2000s, the agency ceased running certain types of operations in the Southeast Asian city-state, because of the sweeping digital surveillance there. The Singaporeans had developed a database that incorporated real-time flight, customs, hotel and taxicab data. If it took too long for a traveler to get from the airport to a hotel in a taxi, the anomaly would trigger an alert in Singaporean security systems. “If there was a gap, they’d go to the hotel, they could flip on the TVs and phones and monitor what was going on” in the room of the suspicious traveler, says the same former senior intelligence official. “They had everything so wired.”

“You used to be able to fly into a country on one name and have meetings in another,” recalls this person. “It limited a lot of capabilities.”

Those concerns spread to other places, like London, where CCTV cameras are omnipresent, and the United Arab Emirates, where facial recognition is ubiquitous at the airport. Today there are “about 30 countries” where CIA officers are no longer followed on the way to meetings because local governments no longer see the need, given that surveillance in those countries is so pervasive, said Dawn Meyerriecks, the CIA’s deputy director for science and technology, in a 2018 speech.

In the 2000s, the explosion in biometrics — such as fingerprints, facial recognition and iris scans — propelled the conversation forward, according to multiple former intelligence officials. U.S. intelligence agencies concluded that in many parts of the world, within a short time, all alias work would likely become impossible.

These fears were largely borne out, say former CIA officials — especially in “hard target” countries like China and Iran. But this trend also affected CIA operations in friendlier countries. By 2012, recalls one former official, some officers were temporarily forbidden to travel for missions in the European Union over fear of exposure, due to widespread sharing of airport biometric data between EU member states. “Facial recognition and biometrics make it very difficult to travel in alias,” says Mike Morell, former acting CIA director and host of the “Intelligence Matters” podcast.

The rise in popularity of consumer DNA kits, which allow people to send in samples of their own DNA, is a growing part of the biometrics problem. Even if an undercover operative hasn’t used a consumer DNA kit, it’s highly likely, say experts, that one of their close relatives has. The Pentagon’s Dec. 20 warning to members of the military not to use these kits appears to be partly in response to that threat.

Greg Hampikian, a biologist at Boise State University and a leading DNA expert, says that with the advent of commercial genetic databases, exposing a spy or other covert operative could be as easy as taking a saliva sample from a cigarette butt or a drinking cup. A suspicious foreign government could send the sample in and potentially find out if the person has been operating under an assumed name.

“It’s right out of a spy novel,” he says.

For spy services, biometric data has become a highly valued currency — leading to a widespread and ongoing campaign by the U.S. and its allies, as well as hostile states, to hack into biometric databases from important airports worldwide. The U.S. has spearheaded breaches of its own, successfully hacking biometric data from the Dubai and Abu Dhabi airports, says a former official. Stealing biometric databases is an attractive strategy for other countries as well. In one case, Chinese intelligence successfully hacked into the biometric data from Bangkok’s airport. “The Chinese have consistently extracted data from all the major transit hubs in the world,” says another former senior official.

Disabling location services on a mobile device does not turn off GPS, and does not significantly reduce the risk of location exposure

Thursday, August 27th, 2020

Location data can be extremely valuable, the National Security Agency notes, and must be protected:

Using a mobile device—even powering it on—exposes location data. Mobile devices inherently trust cellular networks and providers, and the cellular provider receives real-time location information for a mobile device every time it connects to the network. This means a provider can track users across a wide area. In some scenarios, such as 911 calls, this capability saves lives, whereas for personnel with location sensitivities, it may incur risks. If an adversary can influence or control the provider in some way, this location data may be compromised. Public news articles have reported that providers have been known to sell data, including near-real time location data, to third-parties [1].

Location data from a mobile device can be obtained even without provider cooperation. These devices transmit identifying information when connecting to cellular networks. Commercially available rogue base stations allow anyone in the local area to inexpensively and easily obtain real-time location data and track targets. This equipment is difficult to distinguish from legitimate equipment, and devices will automatically try to connect to it, if it is the strongest signal present [2].

Additionally, location data is stored on the mobile device. Past location information can be used to forecast future locations [3]. Other examples of risk exist: websites use browser fingerprinting to harvest location information [4], and WiFi access points and Bluetooth sensors can reveal location information [5].

A mobile device provides geolocation data as a service to apps. This is known as location services, and users can disable them in the settings of a device. Perhaps the most important thing to remember is that disabling location services on a mobile device does not turn off GPS, and does not significantly reduce the risk of location exposure. Disabling location services only limits access to GPS and location data by apps. It does not prevent the operating system from using location data or communicating that data to the network.

Also important to remember is that GPS is not the same as location services. Even if GPS and cellular data are unavailable, a mobile device calculates location using Wi-Fi and/or BT. Apps and websites can also use other sensor data (that does not require user permission) and web browser information to obtain or infer location information [6].

Even if cellular service is turned off on a mobile device, Wi-Fi and BT can be used to determine a user’s location. Inconspicuous equipment (e.g., wireless sniffers) can determine signal strength and calculate location, even when the user is not actively using the wireless services. Even if all wireless radios are disabled, numerous sensors on the device provide sufficient data to calculate location. Disabling BT completely may not be possible on some devices, even when a setting to disable BT exists. When communication is restored, saved information may be transmitted.

If a mobile device has been compromised, the user may no longer be able to trust the setting indicators. Detecting compromised mobile devices can be difficult or impossible; such devices may store or transmit location data even when location settings or all wireless capabilities have been disabled.

Magnetometer readings are much less easy to jam than GPS signaling

Tuesday, August 25th, 2020

The U.S. Air Force is looking into using Earth’s magnetic field as an alternative to GPS:

Magnetic fields emanating from the earth’s surface vary in intensity, just like topography, and so-called magnetic anomaly maps of those fields have existed for years. Back in 2017, Aaron Canciani, an assistant professor of electrical engineering at the Air Force Institute of Technology, set out to see if magnetic sensors (magnetometers) affixed to aircraft could measure the intensity of those magnetic fields and, thus, locate the plane based on where it was in relation to those “landmarks.” His paper (and this video) shows how to outfit a Cessna plane with magnetometers in the rear and the front. Forty flight-hours worth of data and a lot of work reducing noise from the readings proved the idea viable.

But swapping magnetic fields for GPS isn’t easy. Unlike a crisp clear signal from space, factors such as the electrical operations of the plane itself can interfere with a sensor’s ability to detect the strength of the field. This is where artificial intelligence comes in, canceling out the noise from the sensor readings to allow for a better signal and more accuracy.

Researchers in the Air Force’s-MIT Artificial Intelligence Accelerator. community, working with scientists at MIT, continued to work on the problem, publishing their own paper in July. They showed that magnetic field readings can be accurate to ten meters, only slightly inferior to GPS, which is accurate down to three meters. But magnetometer readings are much less easy to jam than GPS signaling. GPS readings rely on a signal sent along a specific wavelength across vast distances. Magnometers just have to read the magnetic environment around the vehicle.

We must be strong there just as we are on earth

Friday, August 21st, 2020

In June 1965, the Directorate of R&D of the Future Weapons Office in Rock Island, Illinois published The Meanderings of a Weapon Oriented Mind When Applied in a Vacuum Such as the Moon:

The purpose of this brochure is to stimulate the thinking of weapon people all the way from those who are responsible for the establishment of requirements, through those who are responsible for funding, to the weapon designer himself.

“If space is truly for peace,” it reads, “we must be strong there just as we are on earth.”

It presents early thoughts and then corrected thinking, like this:

Although the widely advertised temperature of from –250° to +250° F. are actualities on the moon, they are the approximate extremes reached on the surface at midday and midnight. (Days and nights are two weeks long.) The surface of the moon is a poor conductor of heat, consequently a little shade during the day and earth light during the night, plus  a reversible white and black umbrella may be sufficient to keep the temperature in the vicinity of the space suit within limits of from –65° to +125 to +160° F. Assuming a direct proportion to the reflecting area, earth light on the moon will be sixteen times greater than moonlight on the earth.

The discussion involves some calculations. A “5 to 95 percentile” man has an unrestricted maximum line of sight of from 1.4 to 1.6 miles on the moon, with its mean radius of 1080 miles:

Any object propelled horizontally from the shoulder of a man six feet tall (shoulder approximately 5 feet above the surface) would impact the surface after an uninterrupted flight of 2.73 times its velocity. For a velocity of 3000 ft/sec the impact point would be 8190 feet or about 2500 meters. [...] Therefore, the maximum range of a projected object at a velocity of 3000 ft/sec is about 320 miles when propelled at an angle of 45 degrees with the lunar surface. Its maximum ordinate is approximately 80 miles above the surface.

Orbital velocity at the moon’s surface is 5,600 feet per second — totally doable.

Pages 10–16 could have come from an early 1980s sci-fi roleplaying game:

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p14-normal

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p15-normal

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p16-normal

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p17-normal

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p18-normal

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p19-normal

The-Meanderings-of-a-Weapon-Oriented-Mind-When-p20-normal

The flesh-head bolt cuts more than flesh

Friday, July 24th, 2020

Tod Cutler of Tod’s Workshop shot a medieval crossbow (350-lb draw weight) using three different bolt heads (needle bodkin, flesh head, plate-cutter), against three types of flexible medieval armor (gambeson, aketon, and mail):

(Tod and his friends previously showed that medieval longbow arrows explode on impact with a breastplate.)

Amazon is discontinuing the Kindle Cloud Reader

Monday, July 13th, 2020

If it’s true that Amazon is discontinuing the Kindle Cloud Reader, I will be sorely disappointed:

Over the course of the past week, Amazon has been pulling features away from it and it looks like it is on the verge of being discontinued.

We conducted a review a couple of weeks ago on the Kindle Cloud Reader, and since then, the navigation tabs to download ebooks from the Cloud have been removed. The only books you can read, are ones that have been previously downloaded, no new titles can be accessed. Ebooks from certain publishers with DRM cannot be opened anymore, even if you had previously downloaded them. There is a popup window that appears, notifying readers to download the Kindle app for iOS or Android. Amazon also pulled the ability to read books offline, you need a dedicated internet connection to read.

The Damascus-like sample was significantly stronger

Friday, June 26th, 2020

Damascus steel is practically synonymous with artisanal forgework, but a new study led by Philipp Kürnsteiner of the Max Planck Institute for Iron Research shows that it is possible to do something very similar with laser additive manufacturing:

Traditional folded steels combined two steels that varied by carbon content and in their microscale structure, which is controlled by how quickly it cools (by quenching). In this case, the researchers were using a nickel-titanium-iron alloy steel that works well with these 3D printing techniques, in which metal powder is fed onto the work surface and heated with a laser.

Rapid cooling of this steel also produces a crystalline form as in quenched high-carbon steels. But further heat treatment leads to the precipitation of microscopic nickel-titanium particles within the steel that greatly increase its hardness—a pricey material called “maraging steel.”

The team’s idea was to use the layer-by-layer printing process to manipulate the temperatures each layer experienced, alternating softer, more flexible layers with layers hardened by that precipitation process. While printing a cubic chunk of steel, they did this simply by turning the laser off for a couple minutes or so every few layers. The top layer would rapidly cool, converting to the desired crystalline form. Then, as additional layers were added on top, temperatures in the crystalline layer would cycle back up, inducing the precipitation of the nickel-titanium particles.

The first test piece was thrown under the microscope for an incredibly detailed analysis, including a close-enough look at the hard layers to see the precipitated particles. The researchers even atom mapped the layers to verify their composition. So the researchers were able to confirm that the process definitely accomplished what they were aiming for.

[...]

For comparison, they printed another block continuously, producing no hardened layers at all. Both were stretched until they fractured and failed.

The Damascus-like sample was significantly stronger, holding up to about 20 percent more stretching force. It didn’t reach the strength of a typical, traditionally made maraging steel, but the researchers note that this requires “a time-consuming and costly post-process ageing heat treatment.”

No man-made vehicle has ever presented such an awe-inspiring spectacle

Tuesday, June 16th, 2020

When Eisenhower’s Atoms for Peace program was considering a nuclear-powered cargo-passenger ship, Mechanix Illustrated suggested something even better, an Atoms-For-Peace dirigible. What could go wrong?

Unlike a ship, the dirigible moves in an aerial ocean that completely envelops our globe. Hence, it can display its wares anywhere on the face of the earth. Seas, mountains and deserts present no barrier. Neither, considering its mission of peaceful education, should national frontiers.

atoms_dirigible_0

A modern dirigible would be unique, the cynosure of all eyes. Unlike the ship, one-third of whose bulk is hidden by the water in which it rides, the dirigible discloses every inch of its dramatic size as it coasts along against the clear backdrop of the sky. The lower it flies, the more majestic it appears, as anyone who saw the Akron, Macon or Hindenburg will testify. No man-made vehicle has ever presented such an awe-inspiring spectacle as a giant airship breaking through a low-hanging cloud or cruising above the rooftops of a darkened city.

atoms_dirigible_1

Its effect upon the peoples of the world would be many times more potent than that of an ordinary-looking, seaborne freighter. The fact that the dirigible, traveling at relatively low speeds and altitudes, a silvery giant by day and dramatically illuminated at night, will be visible to practically everyone en route, makes it the perfect Atoms-For-Peace transport. It can show our flag in every nook and corner of the globe, scattering as it goes messages of good will in every literate dialect.

atoms_dirigible_3

I suppose that part’s true. What did they propose?

Magnesium, titanium and strong, lightweight Fiberglas promise greater ruggedness and durability with less poundage. This improved weight-strength ratio opens new possibilities to the dirigible engineer. For instance, the single, bottom-keel structure, an outgrowth of age-old surface ship design, might be augmented by external side and top “keels,” containing additional passenger accommodations. These extra stiffeners would vastly strengthen the airship longitudinally without too great a weight penalty.

atoms_dirigible_4

In place of the Akron and Macon pickup gear and airplane hangar, a modern helicopter landing pad and internal hangar deck might be installed atop the hull’s center section. Built in the form of a shock-absorbing elevator, the pad could lift the copter clear of the hull for take-off and after landing, lower it to the level of the protected hangar deck for the safe, comfortable unloading of passengers. This is merely a reversal of the earlier airplane setup with the added safety advantage that both copter and airship travel at the same speed. The copter could provide a ferry service en route and at points where it is inadvisable or impractical to land the airship.

atoms_dirigible_5

Another possibility is the development of water landing gear. A seagoing dirigible, embodying a water-tight hull and lower gas bag, was recently publicized in Germany. MI feels, however, that retractable pontoons of inflated rubber would prove lighter and more efficient. They need not be large, as airships can be trimmed so as to be almost weightless. Water, pumped up from the surface — using the hose gear long since perfected — would provide ballast to hold the ship down when anchored.

Due to the horsepower limitations of the early internal-combustion engines, dirigible designers have always had to install multiple power plants, scattered along the length of the ship. This has not proven too good an arrangement. In addition to difficulties in coordination, the propeller slip-streams have added to the skin friction of the hull with a consequent increase in drag. Modern research indicates that some form of dragless stern propulsion would better the airship’s efficiency and speed by as much as 15 per cent.

With this in mind, MI weighed the various power plant possibilities.

The final solution proved to be the easiest to apply and the one that offers the maximum advantages weight wise. This is a midship atomic steam plant using turbines to generate electricity. Comparatively lightweight wiring car ries the juice to the stern of the ship where an electric motor drives a huge, four-bladed, reversible propeller. To assist in landing and take-off maneuvers, ducted fans are mounted in gimbals in the forward and after stabilizers. These enable the skipper to move his ship up, down or at sidewise angles.

The fission plant is of the latest type, consisting of a central reactor contained within the core of a cylindrical heat-exchanger, the whole being enclosed in lightweight, laminated shielding. Its operation is simple. Steam, generated in the exchanger by the heat of fission, is ducted to twin turbine-generator installations set on either side of the reactor. Passing successively through high and low pressure turbines, the used steam is condensed and routed back to the heat exchanger in a closed system. The turbines drive twin generators and the electricity thus produced, passes into storage batteries. While heavier than a single installation, the duplicate turbine generators provide a safety factor, one being always available in the event of mechanical failure or repair work on the other.

This compact arrangement is mounted on a reinforced deck within the hull and may be readily reached from the exhibition hall directly below it. Galleries around the engine room permit visitors to inspect the unique plant without interference or danger to themselves. If the public exhibition is considered sufficiently important, a water shielded “fishbowl” type of reactor might be used. While heavier and less compact, it would provide a more impressive show.

The power plant used in the atomic submarine Nautilus weighed roughly three times as much as the entire Hindenburg. That seems like a stumbling block.