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Posts Tagged ‘engineering

“Do for the future what you’re grateful the past did for you. (Or what you wish the past had done for you.)”*…

A love letter to infrastructure…

The Nobel Prize–winning developmental economist Amartya Sen describes income and wealth as desirable “because, typically, they are admirable general-purpose means for having more freedom to lead the kind of lives we have reason to value. The usefulness of wealth lies in the things that it allows us to do—the substantive freedoms it helps us to achieve.” This is also a fairly good description of infrastructural systems: they’re a general-purpose means of freeing up time, energy, and attention. On a day-to-day basis, my personal freedom doesn’t come from money per se—it mostly comes from having a home where these systems are built into the walls, which became abundantly clear during the coronavirus pandemic. Stable housing and a salary that covered my utility bills meant that, with the exception of food and taking out the trash, all of my basic needs were met without my ever even having to go outside. It’s worth noting that this is an important reason why guaranteed housing for everyone is important—not just because of privacy, security, and a legible address, but also because our homes are nodes on these infrastructural networks. They are our locus of access to clean water and sewage, electricity, and telecommunications.

But the real difference between money and infrastructural systems as general-purpose providers of freedom is that money is individual and our infrastructural systems are, by their nature, collective. If municipal water systems mean that we are enduringly connected to each other through the landscape where our bodies are, our other systems ratchet this up by orders of magnitude. Behind the wheel of a car, we are a cyborg: our human body controls a powered exoskeleton that lets us move further and faster than we ever could without it. But this freedom depends on roads and supply chains for fuels, to say nothing of traffic laws and safety regulations. In researcher Paul Graham Raven’s memorable formulation, infrastructural systems make us all into collective cyborgs. Alone in my apartment, when I reach out my hand to flip a switch or turn on a tap, I am a continent-spanning colossus, tapping into vast systems that span thousands of miles to bring energy, atoms, and information to my household. But I’m only the slenderest tranche of these collective systems, constituting the whole with all the other members of our federated infrastructural cyborg bodies.

The philosopher John Rawls once offered up a thought experiment, building on the classic question: How best should society be ordered? His key addition was the concept of a “veil of ignorance”: not just that you would live in the society you designed, but that you wouldn’t know ahead of time what role you would have within it. So, while you might want to live in a world where you are an absolute ruler whose every whim is fulfilled by fawning minions, the veil of ignorance means that there is no guarantee you wouldn’t be one of the minions—in fact, given the numerical odds, it’s a lot more likely. Positing a veil of ignorance is a powerful tool to consider more equitable societies.

Seen from this perspective, shared infrastructural systems provide for the basic needs of—and therefore grant agency to—members of a community in a way that would satisfy Rawls. Universal provision of water, sewage, electricity, access to transportation networks that allow for personal mobility, and broadband internet access creates a society where everyone—rich or poor, regardless of what you look like or believe—has access to at least a baseline level of agency and opportunity.

But here’s the kicker: it’s not a thought experiment. We’ve all passed through Rawls’s veil of ignorance. None of us chooses the circumstances of our birth. This is immediate and inarguable if you’re the child of immigrants. If one of the most salient facts of my life is that I was born in Canada, it’s also obvious that I had nothing to do with it. But it’s equally true for the American who proudly traces their family back to ancestors who came over on the Mayflower, or the English family whose landholdings are listed in the Domesday Book. Had I been born in India, my infrastructural birthright would have been far less robust as an underpinning for the life of agency and opportunity that I am fortunate to live, which stems in large part from the sheer blind luck (from my perspective) of being born in Canada.

Our infrastructural systems are the technological basis of the modern world, the basis for a level of global wealth and personal agency that would have been unthinkable only a few centuries ago. But those of us who have been fortunate enough to live as part of a collective cyborg have gained our personal agency at an enormous moral cost. And now anthropogenic climate change is teaching us that there are no others, no elsewhere.

For millennia, these systems have been built out assuming a steady, predictable landscape, allowing us to design long-lived networks where century-old aqueducts underlay new college campuses. But this predictability is becoming a thing of the past. More heat in the atmosphere means warmer weather and shifting climates, with attendant droughts, wildfires, and more frequent and severe hurricanes. But it also increases uncertainty: as the effects of greenhouse gases compound, we may reach tipping points, trigger positive feedback loops, and face other unprecedented changes to climates. Engineers can’t design systems to withstand hundred-year storms when the last century provides little guide to the weather of the next. No matter where in the world you reside, this is the future we will all have to live in. The only question that remains is what kind of world we want to build there.

Our shared infrastructural systems are the most profound and effective means that we’ve created to both relieve the day-to-day burdens of meeting our bodies’ needs and to allow us to go beyond their physiological limits. To face anthropogenic climate change is to become a civilization that can respond to this shifting, unpredictable new world while maintaining these systems: if you benefit from them today, then any future in which they are compromised is recognizably a dystopia. But that “dystopia” is where most of the world already lives. To face anthropogenic climate change ethically is to do so in a way that minimizes human suffering.

Mitigation—limiting the amount of warming, primarily through decarbonizing our energy sources—is one element of this transition. But the true promise of renewable energy is not that it doesn’t contribute to climate change. It’s that renewable energy is ubiquitous and abundant—if every human used energy at the same rate as North Americans, it would still only be a tiny percentage of the solar energy that reaches the Earth. Transforming our energy systems, and the infrastructural systems that they power, so that they become sustainable and resilient might be the most powerful lever that we have to not just survive this transition but to create a world where everyone can thrive. And given the planetwide interconnectedness of infrastructural systems, except in the shortest of short terms, they will be maintained equitably or not at all.

Ursula Franklin wrote, “Central to any new technology is the concept of justice.” We can commit to developing the technologies and building out new infrastructural systems that are flexible and sustainable, but we have the same urgency and unparalleled opportunity to transform our ultrastructure, the social systems that surround and shape them. Every human being has a body with similar needs, embedded in the material world at a specific place in the landscape. This requires a different relationship with each other, one in which we acknowledge and act on how we are connected to each other through our bodies in the landscapes where we find ourselves. We need to have a conception of infrastructural citizenship that includes a responsibility to look after each other, in perpetuity. And with that, we can begin to transform our technological systems into systems of compassion, care, and resource-sharing at all scales, from the individual level, through the level of cities and nations, all the way up to the global.

Our social relationships with each other—our culture, our learning, our art, our shared jokes and shared sorrow, raising our children, attending to our elderly, and together dreaming of our future—these are the essence of what it means to be human. We thrive as individuals and communities by caring for others, and being taken care of in turn. Collective infrastructural systems that are resilient, sustainable, and globally equitable provide the means for us to care for each other at scale. They are a commitment to our shared humanity.

Bodies, agency, and infrastructure: “Care At Scale,” from Debbie Chachra (@debcha), via the indispensable Exponential View (@ExponentialView). Eminently worth reading in full.

See also: “Infrastructure is much more important than architecture“; and resonantly, “Kim Stanley Robinson: a climate plan for a world in flames.”

* Danny Hillis’ “Golden Rule of Time,” as quoted by Stewart Brand in Whole Earth Discipline

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As we build foundations, we might recall that it was on this date in 1904 that the first balloon used for meteorologic research in the U.S. was released near St. Louis, Missouri. The balloon carried instruments that measured barometric pressure, temperature, and humidity, that returned to Earth when the balloon burst.

The first weather balloon was launched in France in 1892. Prior to using balloons, the U.S. used kites tethered by piano wire– the downsides being the limited distance kites could ascend (less than 2 miles), the inability to use them if the wind was too light or too strong, and potential for the kites to break away.

Since this first launch, millions of weather balloons have been launched by the National Weather Service and its predecessor organizations.

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Written by (Roughly) Daily

September 15, 2021 at 1:00 am

“The world is bound in secret knots”*…

It’s knot easy, but it’s important, to understand knots…

From whimsical flower crowns to carelessly tied shoelaces to hopelessly tangled headphones, knots are everywhere. 

That’s not surprising, as knots are quite ancient, predating both the use of the axe and of the wheel and potentially even the divergence of humans from other apes. After all, ropes and cords are practically useless without being tied to something else, making one of the most ancient technologies still remarkably relevant today.

But these tie-offs can be a problem, since knots actually decrease the strength of a rope. When a rope made up of multiple fibers is taut, those fibers all share equal portions of the load. However, the bending and compression where the knot forces the rope to curve (usually around itself, or around the thing it is tied to) create extra tension in only some of the fibers. That’s where the rope will break if yanked with too much force. And this isn’t a small effect: common knots generally reduce the strength of a rope by 20 percent for the strongest ones, to over 50 percent for a simple overhand knot.

Experience has taught surgeons, climbers, and sailors which knots are best for sewing up a patient, or rescuing someone from a ravine, or tying off a billowing sail, but until some recent research from a group at MIT it was hard to tell what actually makes one knot better than another… 

Which knot is the strongest? “The tangled physics of knots, one of our simplest and oldest technologies,” from Margaux Lopez (@margaux_lopez_).

See also: “The twisted math of knot theory can help you tell an overhand knot from an unknot.”

Athanasius Kircher

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As we understand the over and under, we might send constructive birthday greetings to John “Blind Jack” Metcalf; he was born on this date in 1717. Blind from the age of six, he was an accomplished diver, swimmer, card player, and fiddler. But he is best remembered for his work between 1765 and 1792 when he emerged as the first professional road builder in the Industrial Revolution. He laid about 180 miles of turnpike road, mainly in the north of England– and became known as one of the “fathers of the modern road.”

Just before his death, he documented his remarkably eventful life; you can ready it here.

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“They swore by concrete. They built for eternity”*…

Understanding how the materials we use work– and don’t work– together…

For most of a red swamp crayfish’s life, cambarincola barbarae are a welcome sight. Barbarae – whitish, leech-like worms, each a couple of millimeters long – eat the swamp scum off the crayfish’s shells and gills, and in most cases improve the crayfish’s health and life expectancy. Together, barbarae and crayfish form a mutualistic symbiotic relationship. Both species benefit from their cohabitation, and barbarae have evolved to the point where their entire life cycle, from egg to adult, occurs while attached to a crayfish.

But their symbiosis is contextual – a tentative truce. Young crayfish (who molt their shells more frequently and therefore accumulate less scum) don’t need much cleaning, and will take pains to remove barbarae from their shells. And even when molting has slowed and a crayfish has allowed the symbiosis to flourish, there are limits to barbarae’s loyalty: If there isn’t enough food for them to survive, they’ll turn parasitic, devouring their host’s gills and eventually killing them.

Like symbioses, composite materials can be incredibly productive: two things coming together to create something stronger. But like crayfish and barbarae, their outcomes can also be tragic. Rarely are two materials a perfect match for each other, and as the environment changes their relationship can turn destructive. And when composites turn destructive – as was evident in the reinforced concrete when the Champlain Towers North were inspected back in 2018 – the fallout can be catastrophic.

The history of what we now call composite materials goes back many thousands of years. For modern consumers, the most common composites are fiber-reinforced plastics (the colloquial “carbon fiber” and “fiberglass”), but perhaps the first composites in history were reinforced mud bricks. The Mesopotamians learned to temper their bricks by mixing straw into them at least as early as 2254 BC, increasing their tensile strength and preventing them from cracking as they dried. This method continues around the world today.

But by far the most commonly used composite material in history is steel-reinforced concrete. Roman concrete usage started as early as 200 BCE, and almost three centuries later Pliny the Elder included a note about what appears to be high quality hydraulic concrete in his Naturalis Historiae. These recipes were subsequently forgotten, and the material largely disappeared between the Pantheon and the mid nineteenth century. Modern concrete involves some legitimate process control: limestone and other materials are heated to around 900° C to create portland cement, which is then pulverized and mixed with water (and aggregate) to create an exothermic reaction resulting in a hard and durable object. The entire process consumes vast amounts of power and produces vast amounts of carbon dioxide, and the industry supporting it today is estimated to be worth about a half a trillion dollars.

But in spite of the fortunes that have been invested in the portland cement process (as well as in a wide range of concrete admixtures, which are used to tune both the wet mixture and the finished product), the true magic of contemporary concrete is the fact that it is so often reinforced with steel – dramatically increasing its tensile strength and making it suitable for a wide range of structural applications. This innovation arose in the mid-nineteenth century, when between 1848 and 1867 it was developed by three successive Frenchmen. In the late 1870s, around the time that the first reinforced concrete building was built in New York City, the American inventor Thaddeus Hyatt noted a critical quality of the material: through some fantastic luck, the coefficients of thermal expansion of steel and concrete are strikingly similar, allowing a composite steel-concrete structure to withstand warm/cool cycles without fracturing. This quality opened up the floodgates, and in the 1880s the pioneering architect-engineer Ernest Ransome built a string of reinforced concrete structures around the San Francisco Bay Area. From there it was history.

More than any other physical technology, it is reinforced concrete that defines the 20th century. Versatile, strong, and (relatively) durable, the material is critical to life and industry as we know it. Reinforced concrete was the material of choice of Albert Kahn, who with Henry Ford defined 20th century industrial architecture; reinforced concrete is a key part of  nearly every type of logistical infrastructure, from roads to bridges to container terminals; reinforced concrete makes up the literal launch pads for human space travel. It’s a critical component of power plants, dams, wind turbines, and the vast majority of mid- to late-twentieth century homes and apartment buildings. Its high compressive strength makes it ideally suited for footings and foundations; its high tensile strength lets it cantilever and span great distances easily.

But reinforced concrete is really only 140 years old – the blink of an eye, as far as the infrastructure of old is concerned. The Pantheon was built around 125 CE, by which time the Romans had been experimenting with concrete construction for well over 300 years. When we see the Pantheon, we’re seeing a mature method – a technology with full readiness, being used in an architectural style that’s tuned for its physical properties.

By contrast, even our most iconic steel-reinforced concrete buildings are prototypes…

Early on in the history of steel-reinforced concrete, it was known that the high alkalinity of concrete helped to inhibit the rebar from rusting. The steel was said to be sealed within a monolithic block, safe from the elements and passivated by its high pH surroundings; it would ostensibly last a thousand years. But atmospheric carbon dioxide inevitably penetrates concrete, reacting with lime to produce calcium carbonate – and lowering its pH. At that point, the inevitable cracks and fissures allow the rebar inside to rust, whereupon it expands dramatically, cracking the concrete further and eventually breaking the entire structure apart.

This process – carbonatation, followed by corrosion and failure – was often visible but largely ignored into the late twentieth century. Failures in reinforced concrete structures were often blamed on shoddy construction, but the reality is that like the crayfish and the barbarae, the truce between concrete and steel is tentative. What protection concrete offers steel is slowly eaten away by carbonatation, and once it’s gone the steel splits the concrete apart from the inside…

There are of course many potential innovations to come in reinforced concrete. Concrete mixtures made with fly ash and slag produce high strength and durable structures. Rebar rust can be mitigated by using sacrificial anodes or impressed current. Rebar can be made of more weather resistant materials like aluminum bronze and fiberglass. Or the entire project could be scrapped – after all, the CO2 emitted by the cement industry is nothing to thumb your nose at. Whatever we do, we should remember that the materials we work with are under no obligation to get along with one another – and that a symbiotic truce today doesn’t necessarily mean structural integrity tomorrow.

On composites, crayfish, and reinforced concrete’s tentative alkalinity: “A Symbiotic Truce,” from Spencer Wright (@pencerw), whose newsletter, “The Prepared” (@the_prepared), is always an education.

* Gunter Grass

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As we delve into durability, we might recall that it was on this date in 315 that the Arch of Constantine officially opened. A triumphal arch in Rome dedicated to the emperor Constantine the Great, it was constructed of Roman concrete, faced with brick, and reveted in marble.

Roman concrete, like any concrete, consists of an aggregate and hydraulic mortar – a binder mixed with water (often sea water) that hardens over time. The aggregate varied, and included pieces of rock, ceramic tile, and brick rubble from the remains of previously demolished buildings. Gypsum and quicklime were used as binders, but volcanic dusts, called pozzolana or “pit sand”, were favored where they could be obtained. Pozzolana makes the concrete more resistant to salt water than modern-day concrete.

The strength and longevity of Roman marine concrete is understood to benefit from a reaction of seawater with a mixture of volcanic ash and quicklime to create a rare crystal called tobermorite, which may resist fracturing. As seawater percolated within the tiny cracks in the Roman concrete, it reacted with phillipsite naturally found in the volcanic rock and created aluminous tobermorite crystals. The result is a candidate for “the most durable building material in human history.” In contrast, as Wright notes above, modern concrete exposed to saltwater deteriorates within decades.

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“I propose to build for eternity”*…

Florence Duomo as seen from Michelangelo hill

Sent back in time 600 years and tasked with building the world’s largest dome, how would most of us fare? Most of us, of course, are not trained architects or engineers, but then, neither was Filippo Brunelleschi. Known at the time as a goldsmith, Brunelleschi ended up winning the commission to build just such a colossal dome atop Florence’s Cattedrale di Santa Maria del Fiore, which itself had already been under construction for well over a century. The year was 1418, the dawn of the Italian Renaissance, but a break with medieval building styles had already been made, not least in the rejection of the kind of flying buttresses that had held up the stone ceilings of previous cathedrals. Brunelleschi had thus not just to build an unprecedentedly large dome, in accordance with a design drawn up 122 years earlier, but also to come up with the technology required to do so.

“He invented an ox-driven hoist that brought the tremendously heavy stones up to the level of construction,” architect David Wildman tells HowStuffWorks. Noticing that “marble for the project was being damaged as it was unloaded off of boats,” he also “invented an amphibious boat that could be used on land to transport the large pieces of marble to the cathedral.”

These and other new devices were employed in service of an ingenious structure using not just one dome but two, the smaller inner one reinforced with hoops of stone and chain. Built in brick — the formula for the concrete used in the Pantheon having been lost, like so much ancient Roman knowledge — the dome took sixteen years in total, which constituted the final stage of the Cattedrale di Santa Maria del Fiore’s generations-long construction.

Brunelleschi’s masterpiece, still the largest masonry dome in the world, has yet to quite yield all of its secrets: “There is still some mystery as to how all of the components of the dome connect with each other,” as Wildman puts it, thanks to Brunelleschi’s vigilance about concealing the nature of his techniques throughout the project. But you can see some of the current theories visualized (and, in a shamelessly fake Italian accent, hear them explained) in the National Geographic video [below]. However he did it, Brunelleschi ensured that every part of his structure fit together perfectly — and that it would hold up six centuries later, when we can look at it and see not just an impressive church, but the beginning of the Renaissance itself…

How Filippo Brunelleschi, untrained in architecture or engineering, built the world’s largest dome at the dawn of the Renaissance.

For more on the dome, see Ross King’s marvelous 2013 book, Brunelleschi’s Dome: How a Renaissance Genius Reinvented Architecture.

And for more on Brunelleschi— whose other accomplishments include the first precise system of linear perspective, which revolutionized painting and opened the way for the naturalistic styles of Renaissance art– see here.

* Filippo Brunelleschi

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As we go big, we might recall that it was on this date in 330 that Roman Emperor Constantine the Great consecrated Constantinople (on the site of what had been the ancient city of Byzantium; today, Istanbul). Constantine identified the site of Byzantium as a place where an emperor could sit, readily defended, with easy access to the Danube or the Euphrates frontiers, his court supplied from the rich gardens and sophisticated workshops of Roman Asia, his treasuries filled by the wealthiest provinces of the Empire.

The city became famous for its architectural masterpieces, such as Hagia Sophia, the cathedral of the Eastern Orthodox Church. Built by the eastern Roman emperor Justinian I as the Christian cathedral of Constantinople for the state church of the Roman Empire between 532 and 537, the church was then the world’s largest interior space and among the first to employ a fully pendentive dome. It is considered the epitome of Byzantine architecture and is said to have “changed the history of architecture”… It set the bar for Brunelleschi.

Hagia Sophia

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“Everyone should be able to do one card trick, tell two jokes, and recite three poems, in case they are ever trapped in an elevator”*…

Two things make tall buildings possible: the steel frame and the safety elevator. The elevator, underrated and overlooked, is to the city what paper is to reading and gunpowder is to war. Without the elevator, there would be no verticality, no density, and, without these, none of the urban advantages of energy efficiency, economic productivity, and cultural ferment. The population of the earth would ooze out over its surface, like an oil slick, and we would spend even more time stuck in traffic or on trains, traversing a vast carapace of concrete. And the elevator is energy-efficient—the counterweight does a great deal of the work, and the new systems these days regenerate electricity. The elevator is a hybrid, by design…

The history, design, economics, and psychology of the technology that made modern cities possible– the lives of elevators: “Up and Then Down.”

* Daniel Handler

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As we press the button, we might recall that it was on this date in 1527, during the War of the League of Cognac, that an estimated 20,000 mutinous troops of Charles V, Holy Roman Emperor (angered over unpaid wages) carried out the Sack of Rome (which was then part of the papal States). For three days, they pillaged the city, grabbing valuables and demanding tributes. They overpowered (and killed most of) the Swiss Guard, and took Pope Clement VII hostage (in Castel Sant’Angelo); he was freed only after a hefty ransom was paid. Benvenuto Cellini, witnessed the Sack and described the it in his works.

In the aftermath, Rome– which had been the center of Italian High Renaissance culture– never recovered its momentum. Indeed, many historians consider the Sack of Rome the end of the Renaissance.

The Sack of Rome, by Johannes Lingelbach (17th century)

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Written by (Roughly) Daily

May 6, 2021 at 1:01 am

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