In 2018, the Camp Fire devastated a huge swathe of California, claiming 85 lives and costing 16.65 billion dollars. Measured in terms of insured losses, it was the most expensive natural disaster of the year, and the 13th deadliest wildfire in recorded history.
The cause of the fire was determined to be a single failed component on an electrical transmission tower, causing a short circuit and throwing sparks into the dry brush below – with predictable results. The story behind the failure was the focus of a Twitter thread by [Tube Time] this week, who did an incredible job of illuminating the material evidence that shows how the disaster came to be, and how it could have been avoided.
Mismanagement and Money
The blame for the incident has been laid at the feet of Pacific Gas and Electric, or PG&E, who acquired the existing Caribou-Palermo transmission line when it purchased Great Western Power Company back in 1930. The line was originally built in 1921, making the transmission line 97 years old at the time of the disaster. Despite owning the line for almost a full century, much of the original hardware was not replaced in the entire period of PG&Es ownership. Virtually no records were created or kept, and hardware from the early 20th century was still in service on the line in 2018.
Since the widespread manufacture of plastics began in earnest in the early 1950s, plastic pollution in the environment has become a major global problem. Nowhere is this more evident than the Great Pacific Garbage Patch. A large ocean gyre that has become a swirling vortex full of slowly decaying plastic trash, it has become a primary target for ocean cleanup campaigns in recent years.
However, plastic just doesn’t magically appear in the middle of the ocean by magic. The vast majority of plastic in the ocean first passes through river systems around the globe. Thanks to new research, efforts are now beginning to turn to tackling the issue of plastic pollution before it gets out to the broader ocean, where it can be even harder to clean up. Continue reading “Targeting Rivers To Keep Plastic Pollution Out Of The Ocean”→
Netflix has recently announced that they now stream optimized shot-based encoding content for 4K. When I read that news title I though to myself: “Well, that’s great! Sounds good but… what exactly does that mean? And what’s shot-based encoding anyway?”
Later this month, people who use GitHub may find themselves suddenly getting an error message while trying to authenticate against the GitHub API or perform actions on a GitHub repository with a username and password. The reason for this is the removal of this authentication option by GitHub, with a few ‘brown-out’ periods involving the rejection of passwords to give people warning of this fact.
This change was originally announced by GitHub in November of 2019, had a deprecation timeline assigned in February of 2020 and another blog update in July repeating the information. As noted there, only GitHub Enterprise Server remains unaffected for now. For everyone else, as of November 13th, 2020, in order to use GitHub services, the use of an OAuth token, personal token or SSH key is required.
While this is likely to affect a fair number of people who are using GitHub’s REST API and repositories, perhaps the more interesting question here is whether this is merely the beginning of a larger transformation away from username and password logins in services.
While early prototypes for SpaceX’s Starship have been exploding fairly regularly at the company’s Texas test facility, the overall program has been moving forward at a terrific pace. The towering spacecraft, which CEO Elon Musk believes will be the key to building a sustainable human colony on Mars, has gone from CGI rendering to flight hardware in just a few short years. That’s fast even by conventional rocket terms, but then, there’s little about Starship that anyone would dare call conventional.
An early Starship prototype being assembled.
Nearly every component of the deep space vehicle is either a technological leap forward or a deviation from the norm. Its revolutionary full-flow staged combustion engines, the first of their kind to ever fly, are so complex that the rest of the aerospace industry gave up trying to build them decades ago. To support rapid reusability, Starship’s sleek fuselage abandons finicky carbon fiber for much hardier (and heavier) stainless steel; a material that hasn’t been used to build a rocket since the dawn of the Space Age.
Then there’s the sheer size of it: when Starship is mounted atop its matching Super Heavy booster, it will be taller and heavier than both the iconic Saturn V and NASA’s upcoming Space Launch System. At liftoff the booster’s 31 Raptor engines will produce an incredible 16,000,000 pounds of thrust, unleashing a fearsome pressure wave on the ground that would literally be fatal for anyone who got too close.
Which leads to an interesting question: where could you safely launch (and land) such a massive rocket? Even under ideal circumstances you would need to keep people several kilometers away from the pad, but what if the worst should happen? It’s one thing if a single-engine prototype goes up in flames, but should a fully fueled Starship stack explode on the pad, the resulting fireball would have the equivalent energy of several kilotons of TNT.
Thanks to the stream of consciousness that Elon often unloads on Twitter, we might have our answer. While responding to a comment about past efforts to launch orbital rockets from the ocean, he casually mentioned that Starship would likely operate from floating spaceports once it started flying regularly:
While history cautions us against looking too deeply into Elon’s social media comments, the potential advantages to launching Starship from the ocean are a bit too much to dismiss out of hand. Especially since it’s a proven technology: the Zenit rocket he references made more than 30 successful orbital launches from its unique floating pad.
Around the world, governments and city planners have long struggled with the issue of transport. Getting people where they need to be in a timely fashion is key to making a city a comfortable, attractive place to live. As far as public transport is concerned, this typically consists of buses on the roads, and trams and trains on rails.
Down in the city of Adelaide, Australia, things get a little muddled, however. Nestled in a river valley lies a special transportation network known as the O-Bahn, where buses ride on concrete rails and the drivers can even take their hands off the wheel. The system remains a rarity worldwide, and was spawned by a perfect storm of conflicting requirements.
A Child of Circumstance
In the 1970s, the South Australian government found itself backed into a corner. Facing a booming population in the north-eastern suburbs, new transport links with greater capacity were needed to get people to the central business district. Original plans from the 1960s had called for more freeways to be built all over the city to solve the problem. In the face of stiff public opposition, legislation was passed in 1970 blocking the construction of any new freeways for a full decade, forcing the government to consider alternatives.
O-Bahn buses passing at speed near Stephens Terrace. Buses formerly reached speeds up to 100 km/h on the network; this was dropped to 85 km/h in 2012, adding 20 seconds to the average run. Credit: Lewin Day
Despite plans being shelved, a corridor of land stretching from the city to the north-east had already been acquired for freeway construction. This was retained, and studies were commissioned to determine the best transportation solution to suit the needs of the area. The “North East Adelaide Public Transport Review” suggested light-rail or a busway would be the best solution.
Initial plans were proposed to link the north-east with a light-rail tramway that would connect with the existing tramline from the city proper to Glenelg in the west. However, the City of Adelaide protested the plan, believing that extending the existing tramline to the east would damage the city’s carefully planned structure. Plans were made to rectify this by running part of the line underground, massively increasing costs, and the proposal was shelved.
It was at this time, the guided busway in Essen, Germany came to the attention of the state government. Aiming to help reduce congestion by allowing buses to share tram tunnels, it began as a demonstration which later developed into the Spurbus network. The system offered lower cost and higher flexibility than light rail, and avoided the need to carve up the city to hook in to the existing light rail network. Had Adelaide laid out its existing heavy or light rail networks differently, the O-Bahn might not have gotten a look in. However, back in the early 1980s, it was an easy solution in a sea of difficult choices.
Thermites are a double-edged sword. Packing a tremendous energy density, and eager to produce tremendous heat when ignited, thermite is great for welding train tracks. But sometimes you might be looking for a little more finesse. A new approach to 3D printing thermites might just be able to tame the beast.
Most of us do our soldering while sitting safely indoors in a comfortable climate. The biggest dangers we’re likely to face are burnt fingertips, forgetting the heat shrink, or accidentally releasing the smoke monster. But outside of our homes and workshops, there’s a lot of extreme joining of metals going on. No matter where it’s done, welding and brazing in the field requires a lot of equipment, some of which is unwieldy and even more difficult to move around in harsh conditions.
Welding railroad tracks with thermite. Image via YouTube
The utility of brazing is limited by all the complex scaffolding of hardware required to support it. This limiting factor and the discovery of thermite led to exothermic welding, which uses an energetic material to provide enough heat to melt a filler metal and join the pieces. Energetic materials can store a lot of chemical energy and forcefully release it in a short period of time.
Thermites are made of metal oxide and metal powder, often iron oxide and aluminium. When ignited by a source of high heat, thermite compounds undergo an exothermic reduction-oxidation (redox) reaction as the aluminium reduces the number of electrons in the iron oxide atoms. More heat makes the reaction run faster, generating more heat, and so on. The result is molten iron and aluminium oxide slag.
