Engineering and the Immigration Crisis

 

As I write this, the U. S. Supreme Court has just issued a temporary order allowing Title 42, a border restriction applied during the Trump administration, to remain in place until the Court makes a later decision.  This may or may not stem the tide of many thousands of immigrants, largely from Central and South America, who are massing at the U. S. - Mexico border in hopes that the end of Title 42 will increase their chances to enter, and remain in, the United States.

 

At first glance, this ongoing crisis seems to have little to do with engineering as a profession.  But engineers are people, and people have to come from somewhere. 

 

The issue of illegal immigration was brought home to me some years ago when I offered a temporary research job to a bright undergraduate in one of my classes.  He asked to speak to me in private, and when I met him in my office he said, "Well, I'd like to take the job but I can't."

 

"Why not?" I asked.

 

"If they search for a Social Security number for me, they won't find one."  It turns out his parents were Mexican immigrants who entered the U. S. illegally when he was only a child—a Dreamer, in other words.  While I couldn't do anything for him after that, another faculty member helped him get a job at a private company upon graduation, apparently together with legal help to deal with his immigration status.  He has done quite well professionally, and while I don't know if he has obtained U. S. citizenship yet, he deserves to as far as I'm concerned.

 

The problem of immigration over and above what is legally allowed is a classical dilemma.  On the one hand, there is the question of respect for the rule of law.  A sovereign nation has a right to regulate the influx of immigrants as it sees fit, and the U. S. has gone through three distinct phases with regard to immigration policy since the 1860s.  From then up to about 1920, basically almost anyone who wanted to come to this country could do so, with some racially-based exceptions that discriminated against groups such as the Chinese.  A chart from the Migration Policy Institute shows that from 1860 to 1920, nearly 15% of U. S. residents were immigrants, meaning they were born outside the U. S. 

 

Following World War I, a nativist tendency in politics led to the enactment of severe restrictions on immigration with the Emergency Quota Act of 1921, which allowed only a few select (mostly Northern European) countries to send a few people a year here, relatively speaking.  This sent the percentage of immigrant residents into a long decline, which bottomed out at about 5% in 1970, as the absolute number of immigrants entering the country fell from 1930 to 1970. 

 

The attitude toward immigration changed again in the 1960s, and the quota system was repealed by the Immigration and Nationality Act of 1965.  As a result, immigration (both legal and the other kind) began a steep increase which has not yet stopped, although COVID-19 slowed it down some.  As a result, the percentage of U. S. residents who are immigrants has now almost returned to its historic level of 15%.

 

The other horn of the immigration dilemma is the morality of the thing.  The Old Testament Hebrew prophet Malachi had hard words for "'. . . those who turn aside the alien, and do not fear Me,' says the Lord of hosts."  There is the admirable sentiment on a bronze plaque displayed at the Statue of Liberty with the words "Give me your tired, your poor . . . " and most of the migrants huddled just south of El Paso as I write qualify as tired and poor. 

 

In the long run, the only national resource that counts is people.  Without people, you don't have a country—you have Antarctica.  In America's annals of racism, different immigrant groups came under the scornful eye of the establishment:  the Irish following the potato famine of the 1840s, the Italians, the Jews from Eastern Europe, the Chinese and Japanese, and most recently, Mexicans and immigrants from Central and South America.  Should we have let them in, those forebears of John F. Kennedy, Frank Capra, Martin Scorsese, Richard Feynman, Jackie Chan, and my own recently deceased Ph. D. advisor, Tatsuo Itoh, who one day in a rare moment of personal revelation, spoke a few words about what it was like growing up as a five-year-old in Tokyo in 1945? 

 

It is impossible to say "no" to that question, but we have the advantage of hindsight in answering it.  Completely unrestricted immigration, with full citizenship granted to everyone who manages to step across the border, is an idealistic dream that could lead to anti-immigration strife and the kinds of social problems that open-arm countries like Germany are presently dealing with.  Massive disobedience of any duly passed law is inimical to good order and public discipline.  Such laws should either be enforced, or if public sentiment is no longer in favor of them, they should be changed legislatively rather than be used as a political football and kicked around by the courts.

 

That being said, America is a nation of immigrants, and in one way or another, immigration has always been a critical ingredient in the nation's success, a source of vitality and energy that we restrict at our peril.  Let immigration be done decently and in order, not by means of mobs and trailer trucks full of suffocating victims.  But anyone who wants to come here pays us a compliment by doing so, and in due time, we should let them, because they or their descendants can be the future's business leaders, artists, scientists, politicians—and maybe even engineers.

 

Sources:  The Migration Policy Institute's graph on which I based my comments can be viewed at https://www.migrationpolicy.org/programs/data-hub/charts/immigrant-population-over-time

.  I quoted from Malachi 3:15 (New American Standard version).  I also referred to the Wikipedia articles "Immigration policy of the U. S." and "The New Colossus," the poem by Emma Lazarus which is the source of the Statue of Liberty quotation.

Terrorism and the U. S. Power Grid

 

Modern life in advanced industrial societies depends on the availability of certain basic utilities such as water, sewage service, and electric power.  Probably the most vulnerable of these infrastructures is the electric grid, as the others are mostly underground, and the transmission towers, distribution poles, and substations are right out there in the open just asking for someone to come along and shoot them up.  And that's exactly what happened on Saturday, Dec. 3, when two substations operated by Duke Energy in Moore County, North Carolina were sabotaged by unknown intruders.

 

These were no casual drive-by attacks by joyriding teenagers.  The attackers knocked down a gate leading to one of the substations and used high-powered rifles to damage enough equipment so that 40,000 utility customers were without electricity.  Fortunately, Duke Energy repaired or replaced the equipment fast enough so that things were basically back to normal in a few days, but for a while some water utilities were running on emergency power and a local hospital had to switch to its emergency generator.

 

On a larger scale, Russia has been targeting Ukraine's power grid with missiles, and has succeeded in knocking out the power to critical regions of that country, leading to mass evacuations before the coldest winter weather sets in.  Of course, a war is not domestic terrorism, but the extreme vulnerability of power grids make them the target of choice when an enemy wants to get the most harm-inflicting bang for the bucks it spends on missiles and bombs.

 

What can be done to make the grid less vulnerable to terrorist attacks?  It depends on which part of the grid you're examining.

 

Most current power grids consist of relatively few large central generating stations which feed power into the high-voltage transmission lines that cover dozens or hundreds of miles between the generators (generally in rural areas) and the places where most power is used (suburbs and cities).  Where power is needed, substations transform and switch the high-voltage energy into lower-voltage distribution lines, which are the familiar one or three cables at the top of power poles, which connect to the transformers that step the voltage down further to 120 and 240 V for homes and somewhat higher voltages for businesses and industries. 

 

The farther upstream you go in this distribution chain, the more damage you can do, but the harder it gets.  Every now and then, a driver accidentally runs into a power pole and knocks it down.  This results in an outage affecting perhaps a few dozen customers, and is fairly easily repaired in a day or less.  Many localities are wired so that there is more than one pathway from the substation to any given customer, and so power can be restored quite rapidly to most users by isolating the problem and using alternate pathways until the damage is repaired. 

           

On the other hand, an attack on one substation can put thousands of people in the dark, because substations are typically the only source of power for a given region.  But as the Moore County incident showed, service can be restored in a few days, assuming enough spare parts are available.  The most critical component is the substation transformer, because these cost hundreds of thousands of dollars and take a long time to manufacture and transport.  You can't just order one on Amazon and get it in a couple of days.

 

Attacks on high-voltage transmission lines, while not unheard of, are (a) difficult and (b) dangerous, which is why they are so rare.  And as with distribution lines, the utilities have designed multiple pathways for energy to get to most places, so the net harm from one transmission line going out is usually not that widespread, unless the grid is already stressed. 

 

Finally, disabling an entire power plant can cause serious but not catastrophic outages.  Again, most grids are resilient enough to take up the slack with other generating stations, and for terrorists to disable a power plant would be a grand-scale exploit comparable to the 9/11 attacks on the World Trade Center.  The payoff in terms of domestic disruption would be much less, however, which is another reason you don't see a lot of terrorists going after power plants.

 

Nothing was mentioned in the news reports I saw as to whether any security-camera photos were obtained of the perpetrators of the Moore County attacks.  Virtually all substations are probably now equipped with such cameras, but a systematic terrorist would note their locations in advance and make sure to shoot them to pieces before leaving.  The knowledge that they'd be caught sooner or later will discourage some kinds of terrorists, but not others.

 

Finally, there's what you might call the fear factor.  Working with limited budgets, terrorists want to produce the most anguish in the most people for a given effort.  Having your power go out for a couple of days is inconvenient, surely, but it's not in the same league as having your head blown off by a bomb.  There is some speculation that the Moore County attacks were connected with a local drag-queen show, but if all the terrorists wanted to do was to douse the lights at the drag-queen show, it would have been easier to cut off the power for a particular building than to wreck two substations.  Terrorists are not always logical, however.

 

While the power grid is probably one of the more vulnerable types of infrastructure we have, it looks like the kinds of damage that can be done with a small-scale terrorist operation are relatively minor and short-term.  And doing anything that would cause extensive long-term outages would take the operation out of the terrorist class into the civil-war class, because it would require multiple widely-separated and coordinated attacks, or else a concerted effort by what would amount to a whole militia. 

 

I hope they catch the people who knocked out Moore County's power, not only for reasons of justice, but to find out why they chose that particular approach, and to see if we can get ahead of the next bunch who wants to damage the grid.  In the meantime, terrorist attacks on power grids are not going to be high on my worry list, and they shouldn't be on yours either. 

 

Sources:  The online version of the Austin American-Statesman of Dec. 11 carried an editorial by Myron B. Pitts of the Fayetteville Observer entitled "After attacks, how safe are substations?"  I also referred to the Wikipedia article "Moore County substation attack." 

Time Is Running Out on TikTok in the U. S.

 

The video-sharing app TikTok has come up several times in this space in the last year, and never in a complimentary way.  In April, I noted that a couple who learned the suicidal art of fractal woodburning over TikTok succeeded in killing themselves and burning their house down.  In September, a number of U. S. TikTok executives resigned in protest over being forced to take orders from the Chinese corporate headquarters (TikTok is a subsidiary of the Chinese company ByteDance).  And just last week, following revelations that TikTok executives lied about whether data from U. S. users could be accessed from China, several states banned its use from all state-provided devices and members of Congress began looking into the possibility of banning it from the U. S. altogether.

 

A recent article in National Review outlines the increasing concerns that TikTok poses for uses who don't want to be spied on by the Chinese Communist Party (CCP) or be subjected to propaganda and social-media manipulation coordinated by that entity. 

 

According to members of the U. S. House's Oversight Committee, TikTok executives told them that "China-based staff cannot access U. S. users' locations."  A few weeks later, reports indicated that the China-based parent company ByteDance was laying plans to do exactly that. 

 

In common with many China-based corporations, part of ByteDance is owned by the CCP and hosts a CCP committee that meets at the company's headquarters.  We have learned that there are "no meaningful firewalls" between the U. S. division of TikTok and ByteDance, and 300 TikTok and ByteDance employees formerly held jobs with the Chinese state media, which are not known for fairness or objectivity.  While there is no smoking gun showing that TikTok is taking orders direct from Xi Jinping, it's pretty clear that ByteDance and consequently TikTok are heavily influenced by CCP policies and goals, including its policies toward the minority Uyghurs.

 

Among the actions taken against TikTok this week were bans on using it on state-provided devices in South Dakota and Texas.  This follows a bill introduced by Senator Marco Rubio and Representative Mike Gallagher to ban the app outright in the U. S.  The FBI and the Treasury Department are also beginning to view TikTok as a threat to national security, as the app is beginning to cover more general news and political issues, as well as music videos and failed juggling attempts.

 

TikTok appears to be most appealing to people under 30, who increasingly rely on it for Google-type services as well as amusement and social connections.  This poses a problem for laws that would ban it outright, but less radical steps such as insisting that ByteDance relinquish ownership of the U. S.-based TikTok division are more likely to succeed.

 

The Internet famously knows no boundaries:  global, state, or local.  And so it's not surprising that one of the newest rapidly-growing and popular social media apps (it became available worldwide only in 2018) originated in China. 

 

As we have learned in recent years, there is no such thing as a neutral social-media app.  The depths of human depravity ensure that as an app grows beyond a few hundred thousand users, the worst stuff on it will be so bad that some form of control or monitoring becomes necessary, even with the protection of Section 230 of the Communications Decency Act, which exempts internet service providers (e. g. TikTok) from lawsuits over content provided by third parties. 

 

Given that TikTok has to exert some kind of control over its content, and also has to amass user-generated data to satisfy its advertisers, why should we be worried that all this goes on under the watchful eye of the CCP?  It all depends on how well you trust the CCP to act benevolently toward the United States, its citizens, and anybody in the U. S. who has drawn its unfavorable attention. 

 

In my somewhat misspent teenage years, one day I was rummaging through some old books at our house and came upon a slim volume with a black-and-white dust cover that carried the bold title "YOU CAN TRUST THE COMMUNISTS—to do exactly as they say!"  In other words, when a country such as China excoriates another country such as the U. S. for doing things like being friendly to Taiwan and protesting maltreatment of Uyghurs, and China threatens to take over the world in the future, there's no reason not to believe that they are serious. 

 

In such a situation, allowing a CCP-friendly company to embed itself so deeply in the lives of U. S. citizens and residents as to track their movements all the way from Beijing is a dumb thing to do.  Fortunately, more and more government leaders are seeing things that way, and the main question now is how to disengage from TikTok without fomenting a revolution among those 25 and under.

 

Perhaps a corporate breakup similar to what happened with Standard Oil or AT&T is in the best interests both of the U. S. at large, and the millions of TikTok users who depend on their daily fifteen seconds of buffoonery and news reports, or whatever it is they use TikTok for.  But any breakup will have to be rigorously enforced, because corporate breakups have a way of losing effectiveness after a while.  Even in such a relatively benign case as AT&T, after a decade or two the sundered pieces began rejoining like a cut-up flatworm turning into lots of little flatworms that crawl back together for a party.  (That's a lousy simile, but then again, I never took biology.) 

 

The point is that even if the U. S. division of TikTok is formally severed from its ByteDance parent, informal ties through corporate leaders and relationships could persist—in fact, would have to persist unless there was a leadership shakeup along with it.  As one of the most popular apps for sharing music, TikTok worldwide is on track to garner $12 billion in revenue in 2022, so a split-off piece of it would probably attract U. S. investors, who could then dispense with the political slant toward China and concentrate on just making money.

 

That won't mean TikTok's troubles are over, as accusations of addiction and other problems will not be solved by a change of ownership.  But at least if TikTok was cut off from its Chinese corporate parent, we wouldn't be harboring a giant social-media spy network, which is pretty much what it looks like right now.

 

Sources:  I referred to a National Review article calling for the ban of TikTok in the U. S. at https://www.nationalreview.com/2022/12/ban-tiktok-from-operating-in-america/, Gov. Abbott's declaration of a ban of TikTok on state-provided devices at https://gov.texas.gov/news/post/governor-abbott-orders-aggressive-action-against-tiktok, and a Fortune profile of TikTok at https://fortune.com/2022/11/08/tiktok-profits-record-industry-wants-increase-royalties-revenue/.  I also referred to the Wikipedia article on TikTok.

Global Warming, Monsoons, and Engineering

 

Depending on where you live in the U. S., if you ask someone what the worst problem facing humanity is today, you'll get different answers.  On the coasts, apparently, at least in cities and among the knowledge classes, one of the most common answers will be "climate change."  In other parts of the country, it might be" inflation", "immigration", or even something as off-the-wall as "sin." 

 

Regardless of what you think the worst problem is, it turns out that as the atmospheric content of carbon dioxide (CO2) increases, it's getting closer to what the level was in the Pliocene era, some three million years ago.  And according to a recent report in Wired, scientists at Syracuse University have studied ancient leaf-wax deposits that tell them the American Southwest used to have significant monsoons (periods of extended rainstorms) back then, when CO2 levels were not much higher than they are now. 

 

Even today, people living in the states of Arizona, New Mexico, and Nevada know that much of their sparse rainfall comes during the summer monsoon season.  But the Pliocene monsoons were intense enough to make those regions as wet as northern Minnesota, land of a thousand lakes.  That hasn't happened here yet, but if the scientists are right, things may be heading in that direction.

 

How does leaf wax tell us about rainfall millions of years ago?  The wax is made from hydrogen in rainfall, and when it dries up, it blows away and gets deposited in sediment that can be dated accurately.  And somehow, the scientists use these deposits to figure out how much rain was falling and at what time of year.  It's not clear how quantitative this process is, but it's good enough to give the experts confidence that the Pliocene was a pretty wet time for the southwest U. S.  And it may get that way again if current trends continue.

 

What strikes me about the article is not so much the facts of the matter, which are pretty indisputable, but the attitude toward the situation evinced by the researchers.  On the face of it, you'd think that a forecast of more summer rains in regions that are historically dry as a bone would be welcomed as good news.  But that's not the tone the article takes. 

 

Instead, we hear that while some of the intensified monsoon rains will soak into the groundwater, much will run off into the watershed.  And the built infrastructure—roads, bridges, storm sewers, etc.—may not be able to keep up with the more intense rain, leading to intermittent flooding.  The lead researcher, Tripti Bhattacharya, herself says that another downside to more intense monsoons is—believe it or not—wildfires.  More rain means more trees and shrubs, and more trees mean more wildfires. 

 

In Act II of Hamlet, the title character says to his erstwhile friend Rosencrantz, ". . . there is nothing either good or bad, but thinking makes it so."  Depending on one's point of view, the same scientific facts can seem to be either good news or bad news. 

 

Prof. Bhattacharya works in a funding environment in which climate change is the continuing crisis of the moment.  Projects that relate in some way to climate change stand a better chance of getting funded than ones which don't.  And so when asked about the implications of her research, it's understandable that she would come up with consequences that sound dire, because maybe then she'll get more money to find out exactly how dire. 

 

I have no way of reading her mind, and perhaps such a characterization is unfair.  But when the leaders of a culture unite around a pessimistic view of the future, it has serious adverse consequences.  Young people raised in such an environment begin to wonder whether marrying and having children is pointless—or even going on from day to day, getting out of bed to face another day closer to the inevitable catastrophe that will happen if we don't revolutionize our economy to abandon fossil fuels yesterday, if not before.  At best, it leads to an "eat, drink, and be merry, for tomorrow we die" attitude which bodes ill for the long-term survival of a culture, regardless of what the climate does.

 

On the other hand, the Wired article did point out one useful thing that can be done.  As the climate changes, our infrastructure has to keep up with the changes.  Civil engineering projects have historically based their designs pertaining to water and flood control on an unspoken assumption of uniformitarianism.  That is to say, they take historical climate statistics and assume that what happens in the future will be the same, on average, as what has happened in the past. 

 

There is a good and substantiated argument to be made that uniformitarianism in this regard is no longer useful.  With numerous "500-year floods" happening a lot more often lately than statistics say they should, smart and forward-looking engineers should make efforts to forecast the long-term changes in climate that will result from the inevitable rise in CO2 levels that will happen in the coming years.  That is how humanity has ingeniously survived all sorts of adverse situations in the past, ranging from the Ice Age to woolly mammoths and onward:  by noticing threats and planning and executing countermeasures to survive them. 

 

So the Syracuse University findings can be viewed either as more ammunition for a counsel of despair—one more reason to give up on the planet—or as useful information to use in adapting the infrastructure of the arid Southwest to deal with increased intensity of summer monsoons, which, if properly channeled into reservoirs and aquifer recharge zones, could be a very good thing. 

 

Hamlet, the melancholy Dane, viewed Denmark as a prison.  But we don't have to view the planet as a doomed spacecraft.  It's a home that needs some fixing up, but that's how we've been surviving all along.

 

Sources:  The Wired article "Pliocene-Like Monsoons are Returning to the American Southwest," appeared on Nov. 30 online at https://www.wired.com/story/pliocene-like-monsoons-are-returning-to-the-american-southwest/. 

Will Space-Based Wireless Power Beams Solve the Energy Problem?

 

A recent article in a good-news website called The Brighter Side claimed that in a few years, we may be getting lots of energy from space-based wireless power stations.  A research group at Airbus, the European aerospace firm, has built a prototype and has high hopes for the technology's future.

 

Here's how it would work.  A solar panel about 2 km (more than a mile) across would be in geostationary orbit, probably an orbit with a tilt to it so that the satellite would be in continuous sunlight 24/7 rather than going through an Earth-caused eclipse once a day.  The amount of power thus generated—comparable to a standard fossil-fueled or nuclear plant—would then be converted into microwave energy, probably the same type of microwaves that heat your pizza.  The microwaves would be beamed through a large, sophisticated antenna array to suitable locations on Earth equipped with things called "rectennas"—antennas specially designed to receive microwaves and convert them efficiently into DC power.  The power would then be converted into standard AC for transmission on a grid, or conceivably used by mobile devices such as trucks and airplanes.

 

Sounds great, doesn't it?  Compared to earth-based solar panels, the ground-based technology is cheaper.  A rectenna is a lot easier to make than a solar panel.  As solar energy is more intense in space than on earth, it takes less solar-panel area in space to generate a kilowatt than it does on earth.  And there's the flexibility of beaming the power basically anywhere you want it, just as communications satellites beam signals to different locations.  What's in the way of our putting up lots of these and throwing fossil-fuel plants, and nuclear too for that matter, in the existential trash bin?

 

As a trained microwave engineer, I can answer that question.  Microwave power from solar-energy satellites is not a new idea.  Raytheon engineer William C. Brown conceived the idea in the early 1960s, and a key component was a crossed-field amplifier that he had invented earlier.  By 1976, Brown worked with NASA to transmit 30 kW of power over a distance of 1.5 km (almost a mile) using a 26-meter dish and a rectenna that was only 7.3 x 3.5 meters—about 10 by 25 feet.  I saw a video of that demonstration in which they used the power to light up an array of spotlights, and the lights gradually came on as the beam was directed at the rectenna.  The Airbus people have so far demonstrated a link only 36 meters long. 

 

If the idea has been around so long, why hasn't it been deployed commercially yet?  I can think of several reasons.

 

First, as even the optimistic Airbus researchers admit, the orbiting part of the system has to be really big to produce a useful amount of power.  Currently, it seems that the largest structure in orbit is the International Space Station, which is a little longer than a football field.  The solar array envisioned by the Airbus people would be twenty times longer and wider, if it was square.  At the current rate of space commercialization, however, such huge projects in space may become feasible.  But not yet.

 

Once you put the orbiting microwave power station in space, you have to be careful where you aim the beam.  The focusing ability of the station's antenna depends on how big the antenna is, and while it will be smaller than the solar array, you could easily imagine an antenna, say, 100 meters in diameter.  Some simple calculations I will spare the reader tell us that the beam on the ground from an antenna of that size in geostationary orbit, using the microwave-oven wavelength, will expose an area on the ground about 24 miles square to a microwave power density of more than a watt per square meter.  This level of energy would definitely be detrimental to human health and not real good for other vertebrates, either.  So a very large area on the ground, probably covering most of a good-size county, would have to be sequestered off and devoted to a giant rectenna farm.

 

The more speculative statements by the Airbus people of directly conveying microwave energy to mobile platforms such as airplanes are pretty much pipe dreams.  Not all the microwaves would be absorbed by the plane, and so people on the ground underneath would be at risk.  The tighter the beam you want, the larger the antenna has to be, so unless the designers want to make an antenna as big as the solar array, which brings up mechanical difficulties, I don't see how they can direct parts of the beam to highly specific locations on earth, although they could probably manage as many as a dozen or so without too much trouble.

 

The Airbus people are to be congratulated for dusting off an old idea that was clearly premature at the time it originated in the 1960s.  Back then it was prohibitively expensive to launch large structures into orbit.  We can count on both launch and space-based construction costs to decrease in real terms in the future.  So that is one big factor that makes reconsidering wireless power transfer from space a good thing. 

 

The drawbacks are substantial, however:  hazards to people and animals on the ground, the possibility of a space-based error that could send the beam skidding across the countryside into a major population center (there's a sci-fi scenario for you), and the difficulties of upkeep and maintenance—I suspect you'd have to have a few people permanently in space simply to keep the station running.  But it eliminates one of the big problems with most types of renewable energy these days: the fact that it's available only when the sun is out or the wind is blowing.  A properly designed geostationary-orbit power satellite would be available 24/7, through clouds, night and day. 

 

We'll know this technology's time has come when somebody like Elon Musk starts a company to do it.  In the meantime, though, it will remain what it has been for more than fifty years:  only an engineer's dream.

 

Sources:  I thank my wife for calling my attention to the article in The Brighter Side at https://www.thebrighterside.news/post/space-based-solar-power-beams-will-soon-be-powering-our-cities.  I also referred to the Wikipedia article "Wireless power transfer," and my 1975 ITT Reference Data for Radio Engineers handbook for antenna-beam calculations. 

Electric Vehicles and "Ancient Modulation" Don't Mix

 

Many of the currently available electric vehicles (EVs) on the market have a wonderful array of bells and whistles you won't get in a gas-powered car, but some new EV owners are surprised by the lack of one feature:  an AM radio (referred to by radio amateurs as "ancient modulation" because it was the first radiotelephony technology to be invented).

 

Now for most younger readers, an AM radio is not going to be missed.  While radio in general still has its uses for mobile platforms that can't yet conveniently connect to the Internet (although this problem will eventually go away too), AM radio is the oldest and lowest-quality medium in the broadcast hierarchy.  Consequently, much of its programming is devoted to talk shows, sports, and the kind of music that doesn't suffer much from the thunderstorm crackles, power-line buzzes, and night-time fading that AM radio is subject to.  Nevertheless, millions of people listen to AM stations across the U. S. and in other countries, and probably a majority of them do it in their cars.

 

So why do many EV makers leave out the AM-radio feature?  It has to do with an obscure branch of electrical engineering called "electromagnetic interference" (EMI). 

 

EMI studies how electric, magnetic, and electromagnetic fields and their related voltages and currents go from one electronic subsystem (quaintly sometimes called the "aggressor") to another subsystem (called the "victim") and mess up the victim's functioning somehow.  As our world becomes increasingly digital, casual experience with EMI is no longer common, as the characteristic of most digital systems is to work flawlessly until the interference reaches a certain threshold.  Then the whole thing collapses and you get nothing. 

 

Analog systems—the old analog TV that went away about 2009, conventional AM radio that is still with us, and to some extent, FM radio—are different.  As the interference gets stronger, if you were watching an analog TV picture, you'd first see some little random black specks here and there, then solid rows of them, then wider bands and the sound would start to feature a buzz-saw noise, and finally you'd lose everything in a kind of snowstorm (video noise was in fact called "snow".) 

 

AM radio is the same:  a few pops in the speaker here and there, then a steady buzz, and finally the signal is overwhelmed.

 

So why don't most EVs have AM radios?  Because the thing that makes EVs go is kilowatts of electric power, hundreds of volts at dozens of amps, being switched on and off thousands of times a second.  And the efficiency of the electronics depends on how fast those switches work.

 

Unfortunately, switching large amounts of power on and off very fast generates tons (metaphorically speaking) of energy that runs roughshod through the whole AM broadcast spectrum, which ranges from 540 kHz to 1600 kHz.  And a typical EV is just full of such currents, voltages, and magnetic fields, because the currents run through cables by necessity from the battery through the control electronics to the motors. 

 

I've never tried the experiment, but if you had a Tesla or other EV running on a test stand, and you got a little cheap portable AM radio, tuned it to an empty spot in the band, and moved it close to the car, you would in all likelihood be greeted with a banshee set of howls and growls that would be a good soundtrack for a horror film. 

 

Most of the energy thus produced is probably in the form of near-field magnetic fields.  These don't radiate very far (that's why I've been passed by many Teslas on the road while listening to an AM station and never noticed a problem), but within a few feet, which is where you are when you try to put everything into one vehicle, they can be quite intense.  And in contrast to electric fields, which are fairly simple to shield against with conductive screens, magnetic fields are very hard to enclose and shield against.  It takes special types of magnetic metals that are (a) expensive, (b) fragile, and (c) hard to shape, as they are usually supplied in the form of thin tapes that have to be hand-wrapped around the thing to be shielded.

 

Despite what the automakers say, it would be possible to make an EV that wouldn't interfere with an AM radio on board.  Take a standard EV to any big military contractor and tell them what you want.  They'll put a bunch of EMI experts to work, and they'll redesign the whole vehicle.  It'll probably weigh another few hundred pounds when they're finished and cost twice as much as it did before they went to work, but you'll be able to play your AM radio and drive at the same time.

 

See the problem?  That's one of the reasons the EV makers have just quietly dropped the AM radio, because it would mess up everything else if they put it in and made it work.

 

I don't see any good outcomes of this problem for standard AM broadcast services.  There's something called HD radio, as well as several other competing digital-radio services.  The basic idea is to use the allocated FCC frequency band granted to a station (plus maybe some parts of the adjacent channels) and stick a sophisticated orthogonal-frequency-division-multiplexed digital signal in there to carry as many as four audio channels.  This is being tried both with AM and FM, but I suspect the digital AM is wrecked just as thoroughly by EV EMI as the conventional AM is. 

 

So the alternative that at least one article posed, is to hope that in your metropolitan area, your favorite AM signal is also being carried by an HD-radio FM station and you can pick it up that way.  FM signals use much higher frequencies (88-108 MHz), which are much less affected by the electromagnetic trash that EV power electronics puts out. 

 

But I just went to the HD radio website and checked, and poor little San Marcos, halfway between San Antonio and Austin, doesn't have any HD radio signals.  Dallas-Fort Worth is another matter. 

 

So it may be that AM radio for cars, at least the old-fashioned kind, may go the way of buggy-whip holders on automobile dashboards.  Nobody missed those then, and maybe nobody much will miss AM radio in the future.

 

Sources:  Numerous articles are available on the absence of AM radio in EVs, and I referred to this one:  https://www.motorbiscuit.com/am-radio-absence-why-evs-dont-have/.  I also referred to the HD radio website https://hdradio.com/why-hd-radio/ and the Wikipedia article on HD radio.

How Old Is Too Old? The Dallas Air Show Crash

 

On Saturday, Nov. 12, an estimated four thousand or more spectators gathered at the Dallas Executive Airport about ten miles south of downtown to watch a Veterans Day air show put on by the Commemorative Air Force (CAF).  The CAF is a volunteer organization dedicated to keeping older military aircraft flying.  Their motto is "Educate, inspire, and honor."  Most of their inventory of 180 planes worldwide comes from World War II, and prominently featured during the show was a B-17 Flying Fortress, one of only a handful left from WW II service as heavy bombers.  Also featured were P-63 Kingcobra fighter planes. 

 

Around 1:20 PM, the B-17 had just flown low over the airport where the spectators were gathered.  As shown in a number of videos posted after the event, a P-63 approached it from the rear and appeared to collide with the rear section of the bomber.  Both planes fell out of the sky within seconds, and a fireball and black smoke rose from the site of the crash.

 

In a news conference later that afternoon, CAF CEO Hank Coates could provide few specifics out of deference to the National Transportation Safety Board (NTSB), which was scheduled to take over the investigation that evening.  He said the bomber was "fully crewed" which normally means a crew of five.  Adding the pilot of the P-63 means that as many as six people probably died in the crash, which occurred over an empty field.  Information from the Allied Pilots Association confirmed that two of its former members had died in the crash. 

 

In his news conference, CEO Coates emphasized that although all their pilots are volunteers, they spend many hours in training and certification efforts, and often have 20 or 30 years of experience as retired military or airline pilots.  Nevertheless, something went wrong Saturday, and it will take the NTSB some time to figure it out.

 

Once it does, what then?  Let's try to get some perspective on just how dangerous flying CAF planes is.

 

Statistics provided by the NTSB in an Associated Press story of the crash indicate that from 1982 to 2019, 23 people died in 21 accidents involving World-War-II-era planes.  Mr. Coates indicated that the CAF flies an average of 6500 hours a year.  If we assume that has been the case for the past 40 years, we can do a little math to come up with the average fatality rate per million hours flown. 

 

An airline-safety website tells me that for commercial airlines, the current fatality rate is about 0.34 per million hours flown.  General aviation (private planes) is about 50 times worse than that—say 17 per million hours.  If my assumptions are correct, the fatality rate up to 2019 for the CAF is at least 95 per million hours, or about one fatality per 10,000 hours flown—more than five times that of general aviation.

 

Now, no type of aviation is completely safe.  Any human activity, even getting out of bed, involves some risk.  The question here is whether the good that the CAF does—and there is much to be said for it—is worth the risk of getting pilots killed, and the small chance of a much larger number of fatalities.  If the crash had occurred a few hundred yards away from where it did, hundreds of spectators might have been killed.

 

Some will say that the risk, however small, is an essential part of the activity.  If it wasn't at least a little dangerous, it wouldn't be nearly as much fun.  I am not a pilot—the most risky thing I do typically is ride my bike two miles on city roads every day.  So far my worst accident happened when I was looking at the gears of an unfamiliar bike I was riding and ran into a trash barrel.  I rolled off the bike and did an unintentional backflip.  My back was sore for a day or so, but there were no other consequences.  I haven't ridden that bike since, however.

 

I'm sure the FAA has some kind of certification processes for both the hardware the CAF flies and the pilots who fly them.  We will have to wait for the NTSB's investigation to complete before knowing what caused this particular accident: pilot error, mechanical failure, or some combination thereof.  But judging by their fatality rate, it's clear that mostly retired pilots flying seventy-year-old planes is not as safe as flying a 747 to London.

 

I am sympathetic with CAF members who spend hundreds of volunteer hours doing difficult and sometimes dangerous things to keep their old planes in the air and educate the younger generation about what machines and people flying them did during twentieth-century wars.  I love the feel and look of old hardware, and if the CAF flew antique avionics as well as antique planes I'd be right in there with them (unfortunately ,they have to have modern equipment in that department for safety reasons). 

 

At the same time, there will come a day when the hazards of flying piles of fatigued aluminum gets to be simply too dangerous.  We are about out of pilots who flew the planes during WW II, so those who fly them now have had to learn from their elders, and you have a small cadre of skills that has to be handed on in order for the whole CAF to keep flying.  It would be sad to see all that come to an end so that the only place you could see a B-17 would be in a museum, not making a horrible racket as it actually takes off from the ground. 

 

But in the nature of things, that day will come.  Who decides when it comes?  Ideally, the CAF itself, but the other parties involved—the NTSB and the FAA to name two—will have some say in the matter.  I can picture the magnitude of this tragedy leading to public calls for such shows to cease, and that would be a shame.  But it might happen.  The prudent thing is to wait for the NTSB report, and then take stock of the whole situation.  But prudence these days seems to be in short supply.

 

Sources:  I referred to an AP story on the crash carried at https://apnews.com/article/sports-texas-dallas-transportation-air-shows-28e06a464b1f200cfe22b58cc8fdd7f6, a CBS news report at https://www.cbsnews.com/news/world-war-ii-planes-collision-crash-air-force-wings-over-dallas-event-dallas-executive-airport-texas/, a report at

https://www.fox4news.com/news/dallas-executive-airport-crash, and data on aviation safety at https://philip.greenspun.com/flying/safety#:~:text=If%20you're%20really%20really,times%20safer%20than%20general%20aviation.

Breathing While Black: Discrimination By Pulse Oximeters

 

For several years now, you have been able to go to your local drugstore and buy for less than $50 a device called a pulse oximeter.  It's a little thing you clip on your finger, and in a few seconds it displays two numbers.  One is your pulse rate, and the other is supposed to be the percent of maximum capacity of oxygen that your blood is carrying.  Most healthy people show a blood-oxygen percentage of around 98%, but anything considerably less than that means you're not getting enough oxygen to your tissues.

 

Hospitals and doctors have more sophisticated versions of these devices, but apparently they all share the same flaw these days:  they can give falsely reassuring readings on people whose skin has significant melanin content.  Black people, in other words.  So for decades, anyone in that category whose blood oxygen has been monitored with a pulse oximeter has been in danger of going untreated for low blood oxygen, compared to a person whose skin was lighter. 

 

This is not news.  The problem has been known for decades, but received added publicity during the COVID-19 pandemic.  Studies have shown that people of color receive less supplemental oxygen than average during medical treatment, and bad pulse-oximeter readings only exacerbate this problem. 

 

Fortunately, some engineers at Brown University are trying to address the problem.  In a report carried by the health-information site Statnews, Kimani Toussaint, a Black professor of engineering, is reported to be working with students on a patentable idea that will lead to pulse oximeters that give the correct reading no matter who is being tested, and what color their skin is. 

 

I wish them well, and hope that they can make a significant difference in what has to be one of the most embarrassing deficiencies in healthcare technology to come to light in years. 

 

It didn't have to turn out this way.  The same article cites a report in Wired on one of the first oximeters to hit the market way back in the 1970s, developed by what was then a medical branch of the instrumentation company Hewlett-Packard.  In their typically thorough way, H-P included 248 people of color in their volunteer pool of testing subjects, and made sure the readings were as good for them as for the other volunteers. 

 

Of course, the H-P device was a little fancier than the ones you get at Walgreen's.  It examined eight wavelengths of light, not one or two like the current ones do, and was about the size of a small beer cooler.  I'm sure it sold for more than fifty bucks, too.  But it got the oximetry ball rolling, and from that point on it was a question of how cheaply the device could be made, and whether inaccurate readings on a minority of the FDA-required sample population could be disregarded in the approval process, which they apparently were. 

 

I don't think anybody in the healthcare industry deliberately intended to make devices that discriminated in a purely technological way against people of color.  But beyond a certain point, ignorance was no longer an excuse, as studies were published describing the problem and cautioning clinicians not to trust readings of pulse oximeters with darker-skinned patients. 

 

But this is not a good solution.  The right fix, as Toussaint and his colleagues recognize, is to make pulse oximeters that work right for everybody, not just for white folks.  Supposing the Brown academics succeed (which seems pretty well guaranteed at some level, as H-P got it right in the 1970s with vastly inferior technology), what happens then? 

 

Like any industry, the healthcare-technology industry wants to make money and serve its customers as well as it can.  Compared to consumer products, devices sold for healthcare purposes are highly regulated and licensed, and jumping through the regulatory hoops is a cost that makes up a significant fraction of the price.  Unless the FDA insists on changing its rules so that pulse oximeters have to read equally accurately for all colors of patients, the industry doesn't have much of an incentive to adopt a newer technology that does that, whether it's patented by Brown or developed on their own.  For one thing, it means a whole new round of proof-testing and regulatory approval.  And for another thing, the market for pulse oximeters is probably not that big, and making a substantial investment in it for a benefit that will show up in only a minority of patients is a hard marketing sell.

 

I'm reluctant to use the phrase "systemic racism," but it might well apply in this case.  As I said, I don't think any individual manager or pulse-oximeter company set out to discriminate against people of color in developing devices that don't work quite as well for that group.  But somewhere along the long road of development between H-P's giant 1970s device and the $50 versions of today, somebody compromised some things and created the problem.  It would require a huge effort of investigative journalism and probably subpoenas to find out exactly how it happened, but the outcome is clear.

 

Sometimes, adverse publicity by itself will make an industry clean up its act.  Maybe if enough people of color ask questions of their clinicians about pulse oximeters, it will have an effect back up the supply chain and the companies will go to the trouble and expense of dealing with the issue.  But it's not going to happen automatically.  In the old days, a letter-writing campaign might have had some effect.  These days, social media is the obvious channel to use in letting people know there's a problem.  It's a pretty blunt instrument, though, a little like putting out a cigarette with a fire hose, and it can backfire on the user as well.

 

But as the Statnews article quoted Toussaint as saying, this problem is a poster child for increasing diversity in science.  If it's not a problem to you or people you know, you simply tend to ignore it.  Now that we know it's a problem—all of us engineers—I think it's time somebody should do something about it. 

 

Sources:  Statnews carried the article "‘A poster child’ for diversity in science: Black engineers work to fix long-ignored bias in oxygen readings" at https://www.statnews.com/2022/08/19/diversity-in-science-black-engineers-work-to-fix-long-ignored-bias-in-pulse-oximeters/.  The Wired article about the 1970s H-P oximeter is at https://www.wired.com/story/pulse-oximeters-equity/.

Tesla Knows How You Drive—Should You Care?

 

In an article in the October issue of the engineering professional journal IEEE Spectrum, Mark Harris investigates the depth and volume of customer-generated data that Tesla acquires every day from millions of its cars on the road.  The reasons for all this data collection appear to be benign for the time being, but it's truly a new thing in the automotive industry, and potential misuse of the data is something to worry about.

 

In common with all other new cars, Teslas have what are called "event data recorders" (EDRs).   Similar in function to an airliner's black box, the data recorder keeps a constantly updated 5-second record of speed, accelerator and brake conditions, steering, and other data relevant to diagnosing a crash.  In the event of a wreck, the last data set is preserved so that investigators can reconstruct the conditions leading up to the accident.

 

But Tesla cars go way beyond the EDR minimum.  Every minute, the car's GPS location and certain other data are recorded.  And when (not if) the car next gets in touch with its designated wireless hub, it uploads an anonymized version of the data to Tesla HQ through the Internet.  Technically, the car's owner is not linked to the randomized ID number that accompanies the upload, according to an engineer under the alias of Green, who has examined scrapped Teslas (as well as the one he owns) to determine what the famously close-mouthed company is doing.  But as Green points out, if you have anonymized data showing that the car leaves a certain residential address at 8 every morning and returns there at 5 every evening, it's not going to be hard to figure out whose car it is. 

 

Besides the location data, the vehicle's Autopilot system can do something called Shadow Mode, according to former AI head of Tesla Andrej Karpathy.  While the human driver is in control, Autopilot pretends to drive the car and compares its steering and control outputs with what the human actually does.  When there's a discrepancy, Autopilot can take a data sample, including camera images and other details, and upload it to Tesla HQ to enable continuous improvement of the Autopilot algorithms.  Multiply this by the several million Teslas on the road, and you have the world's best test bed for improving autonomous-driving software.  This is yet another example of the tech world's powerful largest-network advantage.  Once a player in a networked system gets to be the biggest, that organization has a huge advantage over the other players because of the synergistic effects of network nodes supporting each other, roughly speaking. 

 

Of course, Musk and his engineers say that is the only reason they're collecting all this data:  to improve the Autopilot system.  But it's come in handy in court at least once, when the father of a teenager who died in the fiery crash of his Tesla sued the company.  Tesla was able to present the judge with a detailed catalog of many times when the driver tore around town at up to 130 MPH, establishing that the teen was not driving responsibly. 

 

In fairness to Tesla, they are only doing what any sensible company would do in the same situation.  If Ford or Volkswagen had happened to climb to the top of the U. S. electric-vehicle heap first with an autonomous car, they would probably be doing more or less the same data-gathering.  In principle, even Tesla owners can decline to have any Internet connection made to the car, but no one knows of any owner who has actually done this.  This is probably because the intersection of (people who buy Teslas) and (people who don't want their hardware connected to the Internet) is the empty set. 

 

Should we worry about Tesla, or any other car company for that matter, collecting huge piles of data on where we drive every minute, and how fast we drive, and how safely we drive?  There are two entities that have strong reasons to access this data, and the main concerns may come from them.

 

The first entity is government—Federal, state, and local.  Already, state governments are beginning to wonder how they will keep collecting highway-tax revenue as more drivers turn to electric vehicles, which completely evade the X-cents-per-gallon gasoline tax that has up to now been a mainstay of highway funding.  It's always seemed to me that if you take a libertarian point of view, the people who use the roads should pay for them.  Up to now, it was impractical to tell who was using which road, but as more cars get equipped with follow-me-everywhere software, the technology to assess road taxes by miles used wouldn't be that hard to do.  But for various political reasons, the states seem instead to be leaning toward a flat annual tax on electric vehicles that will more than make up for the lost gasoline-tax revenues.

 

The other entity that would like to get their hands on the data is the auto-insurance industry.  It's not hard to imagine developing algorithms that would take in a year's worth of digital driving data on you and assess a personalized insurance cost that would precisely reflect your driving habits.  This would be very popular for safe drivers and highly unpopular for the other kind.  Of course, as Autopilot and its ilk get better, the insurance companies are going to have to deal with increasing numbers of vehicles driving themselves, and the liability implications of that situation are far from being sorted out.  But it's likely that the insurance industry will develop some kind of certification process that you'll have to deal with in order to obtain insurance on a car with a given type of autonomous driving capability. 

 

Finally, there is the general creepiness factor that some software somewhere knows where you've been.  But as we've gradually gotten used to that with mobile phones, I suppose it won't be much different if our cars know what our phones know already.

 

For now, just being aware that this data gathering is going on may be the most we can do about it.  But while improving autonomous-vehicle software is a laudable goal, it won't be surprising if hackers or other malevolent actors eventually exploit the data stream that Tesla extracts every day from their cars.

 

Sources:  "The Radical Scope of Tesla's Data Hoard," by Mark Harris appeared on pp. 40-45 of the Oct. 2022 print edition of IEEE Spectrum.

I Take It Back (But Only With iOS 16)

 

Everybody has said something they later regret saying.  If the person you're talking to is right there in front of you, there's nothing you can do to unsay it.  As country singer Jon Langston says in one of his song titles, "I Can't Take Back Words."  But according to tech guru Kim Komando, the new iOS 16 operating system for iPhones (version 8 and later) lets you do that with text messages—sort of.

 

Ever since commercial text messaging became available on mobile phones in the mid-1990s, it has shared with verbal interchanges the fact that once you send a text, it's gone and you can't take it back.  As texting has become easier, people all over the world have incorporated it into their everyday lives, with all sorts of consequences, both good and bad.

 

One might think that the same message spoken to another person in your presence is no different in its effects than one texted to the person on the other side of the world.  But consider some of the differences.

 

Suppose you are with someone whose respect you value, and you say something you immediately regret saying.  Body language, both yours and  your listener's, is a crucial part of the exchange.  If your listener's expression shows hurt or surprise, you have a clue right away that you've said something you shouldn't have.  If the listener moves away, you can try to follow and explain yourself, or at least apologize. 

 

On the other hand, texting the same injudicious message to the same person who is not in your presence can have graver consequences.  The recipient may be so mad that you don't hear back at all, and so you may have no idea how your poorly chosen message was received.  It's also possible that a sentence uttered in jest is clearly a joke in person, but in cold text looks like an insult, leading to misunderstandings and possibly even a breach in the relationship. 

 

I'm not aware of any surveys on this subject, but I wouldn't be surprised if millions of relationships over the last three decades have been damaged by ill-chosen text messages.  Finally, Apple comes to the rescue with the take-it-back option on iOS 16 for iPhones.

 

According to Komando, the feature isn't quite as good as it's advertised to be.  Say you send a text message to someone and change your mind and want to take it back.  First off, both you and the recipient must be running iOS 16 on iPhones.  That's a problem with Android right there. 

 

If your operating systems match, the recipient will be able to see your text until you unsend it.  And you have only two minutes to do so—after that, it's carved in digital stone and Steve Jobs himself couldn't take it back (well, maybe he could, but ordinary mortals can't).

 

And even if you succeed in jerking the message away before your recipient sees it, the receiving phone shows a notification that you sent something and took it back.  Depending on how imaginative your recipient is, this could be even worse than letting the message stand.

 

What if you don't regret the whole message, but just want to take out parts of it—a few cusswords, for example?  The new iOS lets you edit messages, but only within 15 minutes of sending them, and guess what—the recipient can see all your edits if they know to tap your message.  What's the point in that? 

 

Tongues (and now thumbs) get us into more trouble than almost any other part of the body.  As St. James says, ". . . no human being can tame the tongue—a restless evil, full of deadly poison."  (James 3:8).  Most of us are at least teenagers before we learn to control our tongues with even partial success, and some people never learn at all. 

 

Writing emails and texting only makes ill-chosen words worse, for the reasons I stated above, so we need to be especially careful when using electronic media.  Unfortunately, the pressure brought to bear by Facebook, Twitter and company is all the other way.  The last thing they want people to do is text mild, well-considered, and charitable statements back and forth.  The mean zingers get the attention, especially from people with millions of followers. 

 

Apple's move to allow retraction and editing of texts is a move in the right direction, but obviously isn't going to solve all the problems that thoughtless or mean texts cause.  If the texter is thoughtless or mean, it's going to come through in the texts, no matter what kinds of fancy software is in use.  But those of us who try not to be harsh sometimes slip up anyway, and the editing and retraction features may help some.

 

For what it's worth, I follow some practices that have kept me out of trouble with texts and emails many times.  I own a flip phone for which it is rather tedious to send texts—the screen is so small I have to use a stylus, and it gets about every fifth letter wrong and I have to back up and fix it.  I know this would drive 90% of the mobile-phone public insane, but the intentional slowness with which I have to text gives me time to think about what I'm saying. 

           

And for any emails that I want a record of, I usually keep a log of activity and write a draft of the email first.  Only when I think it's what I really want to say do I copy it into the email software and send it. 

 

And for any messages that contain bad news, I usually just call or meet the person face to face.  Texting and emails can be misunderstood, and I'd rather hear or see a person's reaction in real time than just hope it goes okay.

 

I'm glad that those with iOS 16 can now take back or change what they text, but even Apple can't run time backwards, so think before you type.

 

Sources:  The Austin American-Statesman carried Kim Komando's article "What really happens when you edit and unsend iPhone texts?" on p. 6F of the USA Today portion of its Sunday online edition for Oct. 23, 2022.  Jon Langston can be heard singing "I Can't Take Back Words" at https://www.youtube.com/watch?v=O6KrHxPfXyE.