This great video explainer shows the inner workings of a digital-to-analogue converter, using the IBM Selectric's early example of the form to illustrate the mechanism:
Using slow motion video Bill Hammack, the engineer guy, shows how
IBM's revolutionary "golf ball" typewriter works. He describes the
marvelous completely mechanical digital-to-analogue converter that
translates the discrete impulse of the keys to the rotation of the
JPL's video demonstrating the engineering challenges in the precise timing of the descent of a human-crewed Mars lander is nail-biting territory. There's a reason they call the landing "seven minutes of terror."
Geoff Manaugh at BLDGBLOG has been exploring the bizarre world of Swiss self-destructing infrastructure, documented in La Place de la Concorde Suisse, John McPhee's "rich, journalistic study of the Swiss Army's role in Swiss society." It turns out that the Swiss Army specifies that bridges, hillsides, and tunnels need to be designed so that they can be remotely destroyed in the event of societal collapse, pan-European war, or invasion. Meanwhile, underground parking garages (and some tunnels) are designed to be sealed off as airtight nuclear bunkers.
To interrupt the utility of bridges, tunnels, highways, railroads, Switzerland has established three thousand points of demolition. That is the number officially printed. It has been suggested to me that to approximate a true figure a reader ought to multiply by two. Where a highway bridge crosses a railroad, a segment of the bridge is programmed to drop on the railroad. Primacord fuses are built into the bridge. Hidden artillery is in place on either side, set to prevent the enemy from clearing or repairing the damage...
There are also hollow mountains! Booby-trapped cliff-faces!
Near the German border of Switzerland, every railroad and highway tunnel has been prepared to pinch shut explosively. Nearby mountains have been made so porous that whole divisions can fit inside them. There are weapons and soldiers under barns. There are cannons inside pretty houses. Where Swiss highways happen to run on narrow ground between the edges of lakes and to the bottoms of cliffs, man-made rockslides are ready to slide...
The impending self-demolition of the country is "routinely practiced," McPhee writes. "Often, in such assignments, the civilian engineer who created the bridge will, in his capacity as a military officer, be given the task of planning its destruction."
Broad Sustainable Building (BSB) is an innovative Chinese architectural firm whose mission is to erect "medium-cost, super-saving utility buildings and to promote a futuristic urban lifestyle." They are planning to build the world's tallest building, the Sky City Tower in Changsha, Hunan, whose 220 storeys will be erected in 90 days. The timelapse video above shows another BSB project, a 30-storey hotel that went up in 15 days. The company claims its designs are extremely seismically robust and environmentally efficient. From CNNGo:
Its 220 stories will provide a total of 1 million square meters of usable space, linked by 104 elevators.
Zhang said Sky City is expected to consume a fifth of the energy required by a conventional building due to BSB’s unique construction methods, such as quadruple glazing and 15-centimeter-thick exterior walls for thermal insulation.
The company's construction methods also seem to save money.
According to Chinese newspaper 21 Century Business Herald, the total investment in Sky City is RMB 4 billion (US$628 million), compared with US$1.5 billion on Burj Khalifa and US$2.2 billion on Shanghai Tower.
I absolutely love this this new video from Engineer Guy Bill Hammack. Why? Because Hammack managed to make me intensely interested in something I'd previously never really thought twice about—the anodized aluminum coatings that cover—most famously—Apple products.
I sat down to watch this video expecting to be bored. By the end, I was captivated. What more can you ask for in an explainer?
Matt Simmons, who writes the Standalone Sysadmin blog, has been wondering why there are ashtrays in airplane toilets, even though you aren't allowed to smoke anywhere on or near an airplane, and you haven't been allowed to do so for quite some time. It turns out that airplane toilet ashtrays are mandatory: "Regardless of whether smoking is allowed in any other part of the airplane, lavatories must have self-contained, removable ashtrays located conspicuously on or near the entry side of each lavatory door, except that one ashtray may serve more than one lavatory door if the ashtray can be seen readily from the cabin side of each lavatory served." (Code of Federal Regulations for airworthiness). Simmons explains why:
The plane can not leave the terminal if the bathrooms don’t have ashtrays. They’re non-optional.
That’s an awfully strange stance to take for a vehicle with such a stringent “no smoking” policy, but it really does make a lot of sense. Back in 1973, a flight crashed and killed 123 people, and the reason for the crash was attributed to a cigarette that was improperly disposed of.
The FAA has decided that some people (despite the policies against smoking, the warning placards, the smoke detector, and the flight attendants) will smoke anyway, and when they do, there had better be a good place to put that cigarette butt.
The video, made by Mae Ryan for Los Angeles public radio KPCC, traces trash from a burger lunch to its ultimate fate in a landfill. It reminds me of those great, old Sesame Street videos where you got to see what goes on inside crayon factories and peanut butter processing plants. Which is to say that it is awesome.
The process you see here, though, is L.A.-centric, which started me wondering: How much does the trash system differ from one place to another in the United States?
Over the last couple years, as I researched my book on the electric system, I spent a lot of time learning about how different infrastructures developed in this country. If there's one thing I've picked up it's the simple lesson that these systems—which we are utterly dependent upon—were seldom designed. Instead, the infrastructures we use today are often the result of something more akin to evolution ... or to a house that's been remodeled and upgraded by five or six different owners. Watching this video it occurred to me that there's no reason to think that the trash system in place in L.A. has all that much in common with the one in Minneapolis. In fact, it could well be completely different from the trash system in San Francisco.
I'd love to see more videos showing the same story in different places. Know of any others you can point me toward?
In 2010, the Snowbird, a human-powered ornithopter created by a University of Toronto team, became the first HPO to sustain flight. The HPO project at U of T has a great YouTube feed of its various flights since, though it seems largely dormant today.
We review a lot of popular science books around here, but Sustainable Materials (like Sustainable Energy) is a popular engineering text, a rare and wonderful kind of book. Sustainable Materials is an engineer's audit of the materials that our world is made of, the processes by which those materials are extracted, refined, used, recycled and disposed of, and the theoretical and practical efficiencies that we could, as a society, realize.
Allwood and Cullen write about engineering with the elegance of the best pop-science writers -- say, James Gleick or Rebecca Skloot -- but while science is never far from their work, their focus is on engineering. They render lucid and comprehensible the processes and calculations needed to make things and improve things, touching on chemistry, physics, materials science, economics and logistics without slowing down or losing the reader.
The authors quickly demonstrate that any effort to improve the sustainability of our materials usage must focus on steel and aluminum, first because of the prominence of these materials in our construction and fabrication, and second because they are characteristic microcosms of our other material usage, and what works for them will be generalizable to other materials.
From there, the book progresses to a fascinating primer on the processes associated with these metals, from ore to finished product and back through recycling, and the history of efficiency gains in these processes, and the theoretical limits on efficiency at each stage. Lavishly illustrated and superbly organized, this section and the ones that follow it are a crash course in the invisible energy embodied in the bones of our built up world.
But the primary work of the book is to look at how small (and large) changes in our society and business could make important gains in the sustainability of our material use, an important subject as developing nations start to copy the rich world's insatiable appetite for material goods and titanic cities.
For one thing: These musical bots aren't just going through the motions, performing pre-programmed movements in time to a tape of music.
Produced by the Music & Entertainment Technology Laboratory, the HUBOs are operating autonomously (not human-controlled). Their movements are directed by student-developed software to perform the gestures necessary to produce the appropriate notes and beats as dictated by a musical score. Every sound in the video was performed by the robots.
MET-lab student Matthew Prockup created the musical arrangement for drum kit and three "Hubophones", novel percussion instruments designed and constructed by the lab for this performance.
An architect named Michael Green believes he can make wooden skyscrapers that stand 100 storeys tall, and he's prototyping the idea with a 30-storey wooden building in Vancouver. More wooden high-rises are planned in Austria and Norway. Green uses laminated strand lumber, a glue/wood composite, and has char buffers to give it good safety in fires. He claims that his buildings can be cheaper than comparable structures made from traditional steel and concrete, and will have a smaller carbon footprint.
Wood buildings lock in carbon dioxide for the life cycle of a structure, while the manufacture of steel and concrete produces large amounts of CO2 -- the International Energy Agency (IEA) estimate that for every 10 kilos of cement created, six to nine kilos of CO2 are produced.
Green's "Tallwood" structure is designed with large panels of laminated strand lumber -- a composite made of strands of wood glued together. Other mass timber products use layers of wood fused together at right angels that making they immensely strong and able to be used as lode bearing infrastructure, walls and floors.
Despite being made of wood any worries about towering infernos should be banished, says Green, as large timber performs well in fires with a layer of char insulating the structural wood beneath.
"It may sound counter-intuitive, but performing well in a fire is something inherent in large piece of wood, that's why in forest fires the trees that survive are the largest ones," he says.
Why does electric infrastructure affect our ability to make energy more sustainable? How is the electric grid like a lazy river at the water park? And why should you never, ever go fishing with a salesman? Learn the answers to these questions—and more—when I speak at the University of Illinois at Urbana-Champaign on Monday, March 12. My presentation starts at 3:00 pm in room 355 of the Mechanical Engineering Building. It's free, and open to the public. (Can't make it to the speech? You can also find out the answers to these questions by reading my book, Before the Lights Go Out.)
Above, a PBS NewsHour report by science correspondent Miles O'Brien which I helped shoot, on the subject of tissue engineering. The goal in this field: Grow tissue or even whole organs to repair damaged or diseased human bodies.
The report focuses in part on Isaias Hernandez, a 26-year old Marine whose leg was badly injured in an artillery attack on his convoy, in Iraq. "It looked like a chicken, like if you would take a bite out of it down to the bone," he tells Miles.
Dr. Steve Badylak of the McGowan Institute for Regenerative Medicine at the University of Pittsburgh harvested material from a pig bladder to grow replacement muscle in the young Marine's leg.
This awesome rollercoasteroid staircase is underway in Germany:
The walkable, large outdoor sculpture Tiger & Turtle – Magic Mountain is currently in construction on the Heinrich Hildebrand Höhe in Duisburg Wanheim (D). It overtops the plateau with the artificially heaped-up mountain by 21m | 23yd so the visitor can rise by more than 45m | 49yd above the level of the landscape and enjoy an impressive view over the Rhine.