Category Archives: Engineering

Ferries make more sense than fast new trains.

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Per pound mile of material, the transport cost by ship is 1/4 as much as by train, and about 1/8 as much as by truck. Ships are slower, it is true, but they can go where trucks and trains can not. They cross rivers and lakes at ease and can haul weighty freight with ease. I think America could use many more ferries, particularly drive-on, fast ferries. I don’t think we need new fast rail lines, because air travel will always be faster and cheaper. The Biden administration thinks otherwise, and spends accordingly.

Amtrak gets $30 Billion for train infrastructure this year, basically nothing for ferries.

The Biden administration’s infrastructure bill, $1.2 Trillion dollars total, provides $30 Billion this year for new train lines, but includes less than 1% as much for ferries, $220 million, plus $1B for air travel. I think it’s a scandal. The new, fast train lines are shown on the map, above. Among them is a speed upgrade to the “Empire Builder” train running between Chicago and Seattle by way of Milwaukee. I don’t think this will pay off — the few people who take this train, takes it for the scenery, I think, and for the experience, not to get somewhere fast.

There is money for a new line between Cleveland and Detroit, and for completion of the long-delayed, and cost-over-run prone line between LA and San Francisco. Assuming these are built, I expect even lower ridership since the scenery isn’t that great. Even assuming no delays (and there are always delays), 110 mph is vastly slower than flying, and typically more expensive and inconvenient. Driving is yet slower, but when you drive, you arrive with your car. With a train or plane, you need car rental, typically.

New Acela train, 150 mph max. 1/4 as fast as flying at the same price.

Drive-on ferries provide a unique advantage in that you get there with your car, often much faster than you would with by driving or by train. Consider Muskegon to Milwaukee (across the lake), or Muskegon to Chicago to Milwaukee, (along the lake). Cleveland to Canada, or Detroit to Cleveland. No land would have to be purchased and no new track would have to be laid and maintained. You’d arrive, rested and fed (they typically sell food on a ferry), with your car.

There’s a wonderful song, “City of New Orleans”, sung here by Arlo Guthrie describing a ride on the historic train of that name on a trip from Chicago to New Orleans, 934 miles in about one day. Including stops but not including delays, the average speed is 48 mph, and there are always delays. On board are, according to the song, “15 restless riders, 3 conductors, and 25 sacks of mail.” The ticket price currently is $200, one way, or about as much as a plane ticket. The line loses money. I’ve argued, here, for more mail use to hep make this profitable, but the trip isn’t that attractive as a way to get somewhere, it’s more of a land-cruise. The line is scheduled for an upgrade this year, but even if upgraded to 100 mph (14 hours to New Orleans including stops?) it’s still going to be far slower than air travel, and likely more expensive, and you still have to park your car before you get on, and then rent another when you get off. And will riders like it more? I doubt it, and doubt the speed upgrade will be to 100 mph.

Lake Express, 30 mph across Lake Michigan

Ferry travel tends to cost less than train or plane travel because water traffic is high volume per trip with few conductors per passenger. At present, there are only two ferryboats traveling across Lake Michigan, between Michigan and Wisconsin, Milwaulkee to Muskegon. They are privately owned, and presumably make money. The faster is the Lake Express, 30 mph. It crosses the lake in 2.5 hours. Passenger tickets cost $52 one way, or $118 for passenger and car. That’s less than the price of an Amtrak ticket or a flight. I think a third boat would make sense and that more lines would be welcome too. Perhaps Grand Haven to Racine or Chicago.

Route of the Lake Express. I’d like to see more like this; St. Joseph to Milwaukee say, and along Lake Erie.

Currently, there are no ferries across Lake Erie. Nor are there any along Lake Erie, or even across Lake St. Clair, or along the Detroit River, Detroit to Toledo or Toledo to Cleveland. These lines would need dock facilities, but they would have ridership, I think. New York’s Staten Island ferry has good ridership, 35,000 riders on a typical day, plus cars and trucks. In charge are roughly 120 engineers, captains and mates, one employee for every 300 passengers or so. By comparison, Amtrak runs 300 trains that carry a total of 87,000 passengers on an average day, mostly on the east coast. These 300 trains are run by 17,100 employees as of fiscal year 2021, one employee for every 4 passengers. Even at the slow speeds of our trains the cost is far higher per passenger and per passenger mile.

The Staten Island ferry is slow, 18.5 mph, but folks don’t seem to mind. The trip takes 20 minutes, about half as long as most people’s trips on Amtrak. There are also private ferry lines in NY, many of these on longer trips. People would take ferries for day-long trips along our rivers, I think. Fast ferries would be nice, 40 mph or more, but I think even slow ferries would have ridership and would make money. A sea cruise is better than a land cruise, especially if you can have a cabin. On the coal-steam powered, Badger, you can rent a state-room to spend the night in comfort. Truckers seem to like that they cover ground during their mandatory rest hours. The advantage is maximized, I think, for ferry trips that take 12 hours or so, 250 to 350 miles. That’s Pittsburgh to Cincinnatti or Chicago to Memphis.

New York’s Staten Island ferry leaves every 15 minutes during rush hour. Three different sizes of boat are used. The largest carry over 5000 passengers and 100 cars and trucks at a crossing.

A low risk way to promote ferry traffic between the US and Canada would be to negotiate bilateral exemption to The Jones Act and its Canadian equivalent. Currently, we allow only US ships with US crews for US travel within the US.* Cabotage it’s called, and it applies to planes as well, with exemptions. Canada has similar laws and exemptions. A sensible agreement would allow in-country and cross-country travel on both Canadian and US ships, with Canadian and/or US crew. In one stoke, ridership would double, and many lines would be profitable.

Politicians of a certain stripe support trains because they look futuristic and allow money to go to friends. Europeans brag of their fast trains, but they all lose money, and Europe had to ban many short hop flights to help their trains compete. Without this, Europeans would fly. There is room to help a friend with a new ferry, but not as much as when you buy land and lay track. We could try to lead in fancy ferries going 40 mph or faster, providing good docks, and some insurance. Investors would take little risk since a ferry route can be moved**. Don’t try that with a train.

In Detroit we have a close up of train mismanagement involving the “People Mover.” It has no ridership to speak of. Our politicians then added “The Q line” to connect to it. People avoid both lines. I think people would use a ferry along the Detroit river, though, St. Claire to Wyandotte, Detroit, Toledo — and to Cleveland or Buffalo. Our lakes and rivers are near-empty superhighways. Let’s use them.

Robert Buxbaum, January 2, 2024. *The US air cabotage act (49 U.S.C. 41703) prohibits the transportation of persons, property, or mail for compensation or hire between points of the U.S. in a foreign civil aircraft. We’ve managed exemptions, though, e.g. for US air traffic with Airbus and Embraer planes. We can do the same with ferries.

** I notice that it was New York’s ferries, and their captains, that rescued the people on Sullenberger’s plane when it went down in the Hudson River — added Jan. 6.

Cybertruck an almost certain success

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Leading up to the Cybertruck launch 4 weeks ago, the expert opinion was that it was a failure. Morgan Stanley, here dubbed it as one, as did Rolling Stone here. Without having driven the vehicle, the experts at Motor trend, here, declared it was worse than you thought, “a novelty” car. I’d like to differ. The experts point out that the design is fundamentally different from what we’ve made for years. They claim it’s ugly, undesirable, and hard to build. Ford’s F-150 trucks are the standard, the top selling vehicle in the US, and Cybertruck looks nothing like an F-150. I suspect that, because of the differences, the Cybertruck can hardly fail to be a success in both profit and market share.

Cybertruck pulls a flat-bed trailer at Starbase.

Start with profit. Profit is the main measure of company success. High profit is achieved by selling significant numbers at a significant profit margin. Any decent profit is a success. This vehicle could trail the F-150 sales forever and Musk could be the stupidest human on the planet, so long as Tesla sells at a profit, and does so legally, the company will succeed. Tesla already has some 2 million pre-orders, and so far they show no immediate sign of leaving despite the current price of about $80,000. Unless you think they are all lying or that Musk has horribly mispriced the product, he should make a very decent profit. My guess is he’s priced to make over $10,000 per vehicle, or $20B on 2 million vehicles. Meanwhile, no other eV company seems to be making a profit.

The largest competing electric pickup company is Rivian. They sold 16,000 electric trucks in Q3 2023, but the profit margin is -100%. This is to say, they lose $1 for every $1 worth of sales –and that’s unsustainable. Despite claims to the contrary, a money-losing business is a failure. The other main competitors are losing too. Ford is reported to lose about $50,00 per eV. According to Automotive News, here, last week, Ford decided to cut production of its electric F-150, the Lightning, by 50%. This makes sense, but provides Cybertruck a market fairly clear of US e-competition.

2024 BYD, Chinese pickup truck

Perhaps the most serious competitor is BYD, a Chinese company backed by the communist government, and Warren Buffet. They are entering the US market this month with a new pickup. It might be profitable, but BYD is relatively immune to profitability. The Chinese want dominance of the eV market and are willing to lose money for years until they get it. Fortunately for Tesla, the BYD truck looks like Rivian’s. Tesla’s trucks should exceed them in range, towing, and safety. BYD, it seems, is aiming for a lower price point and a different market, Rivian’s.

A video, here, shows the skin of a Cybertruck is bulletproof to 9mm, shotgun, and 45 caliber machine gun fire. Experts scoff at the significance of bulletproof skin — good for folks working among Mexican drug lords, or politicians, or Israelis. Tesla is aiming currently for a more upscale customer, someone who might buy a Hummer or an F-250. This is more usable and cheaper.

Don’t try this with other trucks.

Another way Cybertruck could fail is through criminal activity. Musk could be caught paying off politicians or cheating on taxes or if the trucks fail their safety tests. So far, Cybertruck seems to meet Federal Motor Vehicle Safety Standards by a good margin. In a video comparison, here, it appears to take front end collisions as well as an F-150, and appears better in side collisions.

This leaves production difficulty. This could prevent the cybertruck from being a big success, and the experts have all harped on this. The vehicle body is a proprietary stainless steel, 0.07″ thick. Admittedly it’s is hard to form, but Tesla seems to manage it. VIN number records indicate that Tesla had delivered 448 cybertrucks as Friday last week, many of them to showrooms, but some to customers. Drone surveys of the Gigafactory lot show that about 19 are made per day. That’s a lot more than you’d see if assembly was by hand. Assuming a typical learning curve, it’s reasonable to expect some 600 will be delivered by December 31, and that production should reach 6000 per month in mid 2024. At that rate, they’ll be making and selling at the same rate as Rivian or Ford, and making real money doing it. The stainless body might even be a plus, deterring copycat competition. Other pluses are the add-ons, like the base-camp tent option, a battery extension, a ramp, and (it’s claimed) some degree of sea worthiness. Add-ons add profit and deter direct copying (for a time).

Basecamp, tent option.

So why do I think the experts are so wrong? My sense is that these people are experts because of long experience at other companies — the competitors. They know what was tried, and that innovation failed. They know that their companies chose not to make anything like a Cybertruck, and not to provide the add-ons. They know that the big boys avoid “novelty cars” and add-ons. There is an affinity among experts for consensus and sure success, the success that comes from Chinese companies, government support and international banking. If the Cybertruck success is an insult to them and their expertise. Nonetheless, if Cybertruck succeeds, they will push their companies towards a more angular design plus add-ons. And they will claim cybertruck is no way novel, but that government support is needed to copy it.

Robert Buxbaum, December 25, 2023.

Solving the evening solar power problem

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Solar power is only available during the day, and people need power at night too. As a result, the people of a town will either need a lot of storage, or a back-up electric generator for use at night and on cloudy days. These are expensive, and use gasoline (generally) and they are hard to maintain for an individual. Central generated alternate power is cheaper, but the wires have to be maintained. As a result, solar power is duck curve, or canon curve power. It never frees you from hydrocarbons and power companies, and it usually saves no money or energy.

People need power at twilight and dawn too, and sunlight barely generates any power during these hours, and sometimes clouds appear and disappear suddenly while folks expect uniform power to their lights. The mismatch between supply and demand means that your backup generator, must run on and off suddenly. It’s difficult for small, home generators, but impossible for big central generators. In order to have full power by evening, the big generators need to run through the day. The result is that, for most situations, there is no value to solar power.

Installed solar power has not decreased the amount of generation needed, just changed when it is needed.

Power leveling through storage will address this problem, but it’s hardly done. Elon Musk has suggested that the city should pay people to use a home battery power leveler, a “power wall” or an unused electric car to provide electricity at night, twilight, and on cloudy days. It’s a legitimate idea, but no city has agreed, to date. In Europe, some locations have proposed having a central station that generates hydrogen from solar power during the day using electrolysis. This hydrogen can drive trucks or boats, especially if it is used to make hythane. One can also store massive power by water pumping or air compression.

Scottsbluff Neb. solar farm damaged by hail, 6/23.

In most locations, storage is not available, so solar power has virtually no value. I suspect that, at the very least, in these locations, the price per kWh should be significantly lower at noon on a sunny day (1/2 as expensive or less). The will cause people to charge their eVs at noon, and not at midnight. Adjusted prices will cause folks to do heavy manufacturing at noon and not at midnight. We have the technology for this, but not the political will, so far. Politicians find it easier to demand solar, overcharge people (and industry) and pretend to save the environment.

Robert Buxbaum Aug 8, 2023

Chemistry, chemical engineering joke

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A catalyst walks into a bar. The bartender says, “We can’t serve you.”

The catalyst asks, “Why not?”

The bartender says, “The last time you were here, you started something.”

Robert Buxbaum, July 14, 2023 (Bastille day). If you like this, maybe you’d like another, chemistry joke or this physics joke.

I’d like to expand the Jones act so more ships can do US trade.

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If you visit most any European port city, you’ll see a lot more shipping than in the Midwestern US. In Detroit, where I am, your’ll see an occasional ore boat from Wisconsin, and an occasional tourist cruise, but nothing to compare to German, Belgian, or Turkish ports. The reason for the difference is “The Jones act.”

The port of Istanbul with many ships

The Jones act , also known as “The Merchant Marine Act of 1920”, requires that all ships depositing cargo or people between US ports must be US owned, US built, US captained, US flagged, and at least 70% US manned. This raises costs and reduces options. The result is that few ships can move people or cargo between US cities, and these ships are older and less efficient than you’ll see elsewhere. World wide water traffic costs about 1/8 that of rail traffic per ton-mile, but in the US, the prices are more comparable. The original justification was to make sure the US would always have a merchant marine. The Jones act does that, sort of, but mostly, it just makes goods more expensive and travel more restrictive.

The port of Detroit — we rarely see more than one ship at a time.

Because it does some good, I don’t want to get rid of the Jones act entirely, but I’d like to see US shipping options expanded. Almost any expansion would do, e.g. allowing 50% US manned ships delivering along US rivers, or expanding to allow Canadian built ships or flagged, and ships that are more than 50% US owned, or expanding to any NAFTA vessel that meets safety standards. Any expansion of the number of ships available and would help.

The jones act increase the price of oil transport by a factor of five, about.

Currently, the only exceptions to the Jones act are for emergencies (Trump voided the act during several storms) and for ships that visit a foreign port along the route. This exception is how every cruise ship between California and Hawaii works. They’re all foreign, but they stop in Mexico along the way. Similarly, cruises between Florida and Puerto Rico will stop in Bermuda typically, because the ships are foreign owned. Generally, passengers are not allowed to get off in Puerto Rico, but must sleep on board. This is another aspect of the Maritime act that I’d like to see go away.

Because of the Jones act, there is some US freight-ship building, and a supply of sailors and captains. A new, US ore-ship for the Great Lakes was launched last year, so far it’s been used to carry salt. There is also a US built and operated cruise ship in Hawaii, the “Pride of America,” that makes no stop in Mexico. I’d like to see these numbers expanded, and the suggestions above seem like they’d do more good than harm, lowering prices, and allowing modern container ships plus roll-on-roll-off car transports. Our rivers and lakes are super highways; I’d like to see them used more.

The port of Antwerp – far busier than Detroit.

Another way to expand the Jones act while perhaps increasing the number of US-built and operated ship would be through a deal with Canada so that ships from either country could ply trade on either countries rivers. As things stand, Canada has its own version of the Jones act, called the Coastal Trade Act where Canadian vessels must be used for domestic transport (cabotage) unless no such vessel is available. Maybe we can strike a deal with Canada so that the crew can be Canadian or US, and where built ships in either country are chosen on routes in either country, providing they meet the safety and environmental requirements of both.

Robert Buxbaum, June 14, 2023.

Rain barrels aren’t much good. Wood chips are better, And I’d avoid rain gardens, even as a neighbor.

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A lot of cities push rain barrels as a way to save water and reduce flooding. Our water comes from the Detroit and returns to it as sewage, so I’m not sure there is any water saving, but there is a small cash saving (very small) if you buy 30 to 55 gallon barrels from the city and connect them to the end of your drain spout. The rainwater you collect won’t be pure enough to drink, or safe for bathing, but you can use it to water your lawn and garden. This sounds OK, even patriotic, until you do the math, or the plumbing, or until you consider the wood-chip alternative.

The barrels are not cheap, even when subsidized they cost about $100 each. Add to this the cost and difficulty of setting up the collection system and the distribution hose. Water from your rain barrel will not flow through a normal nozzle as there is hardly any pressure. Expect watering to take a lot longer than you are used to.

40 gallon rain barrels. Two of these give about 70 usable gallons every heavy rain fall. That’s about 70¢ worth.

In Michigan you can not leave the water in your barrel over the winter, the water will freeze and the barrel will crack. You have to drain the tank completely every fall, an almost impossible task, and the tank is attached to a rainspout and the last bit of water is hard to get out. Still, you have to do it, or the barrel will crack. And the savings for all this is minimal. During a rainy month, you don’t need this water. During a dry month, there is no water to use. Even at the best, the The marginal cost of water in our town is less than 1¢ per gallon. For all the work and cost to set up, two complete 40 gallon tanks (like those shown) will give you at most about 70 usable gallons. That’s to say, almost 70¢ per full filling.

How much lawn can you water? Assume you like to water your lawn to the equivalent of 1″ of rain per week, your 70 gallons will water about 154 ft2 of lawn or garden, virtually nothing compared to the typical Michigan 2000 ft2 lawn. You’ll still have to get most of your water from the city’s main. All that work, for so little benefit.

Young trees with chip volcanos, 1 ft high x18″. Spread the chips to the diameter of the leaves.You don’t need more than 2″.

A far better option is wood chips. They don’t cover a lawn, but they’re great for shrubs, trees or a garden. Wood chips are easy to spread, and they stop weeds and hold water. The photo at left shows a wood chips around the shrubs, and a particularly poor use of wood chips around the trees. For shrubs, trees, or a garden, I suggest you put down 1 to 2 inches of wood chips. Surround a young tree at that depth to the diameter of the branches. Do not build a “chip volcano,” as this lazy landscaper has done.

Consider that, covering 500 ft2 of area to a depth of 1.5 inches will take about 60 cubic feet of wood chips. That will cost about $35 dollars at the local Home Depot. This is enough to hold about 1.25″ or rainwater, That’s about 100 ft3 or water or 800 gallons. The chips prevent excess evaporation while preventing weeds and slowly releasing the water to your garden. You do no work. The chips take almost no work to spread, and will keep on working for years, with no fear of frost-damage. A as the chips stop working, they biocompost slowly into fertilizer. That’s a win.

There is a worst option too, called a rain garden. This is often pushed by environmental-gooders. You dig a hole near your downspout, perhaps ten feet in diameter, by two feet deep, and plant native grasses (weeds). When it rains, the hole fills with water creating a mini wetland that will soon smell like the swamp that it is. If you are not lucky, the water will find a way to leak into your basement. If that’s your problem look here. If you are luckier, your mini-swamp will become the home of mosquitos, frogs, and snakes. The plants will grow, then die, and rot, and look awful. It is very hard to maintain native grasses. That’s why people drain swamps and grow trees or turf or vegetables. If you want to see a well-maintained rain garden, they have two on the campus of Lawrence Tech. A wetland isn’t bad, but you want drainage, Make a bioswale or muir.

Robert Buxbaum, May 31, 2023. I ran for water commissioner some years back.

Hydrogenation, how we’ve already entered the hydrogen economy

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The hydrogen economy is generally thought to come in some distant future, where your car (and perhaps your home) runs on hydrogen, and the hydrogen, presumably, is made by clean nuclear or renewable solar or wind power. This is understood to be better than the current state of things where your car runs on dirty gasoline, and your home runs on coal or gas, except when the sun is shining bright and the wind is blowing hard. Our homes and cars can not run on solar or wind alone, although solar cells have become quite cheap, because solar power is only available in the daytime, basically for 6 hours, from about 9AM to 3PM. Hydrogen has been proposed as a good way to store solar and wind energy that you can’t use, but it’s not easy to store hydrogen — or is it? I’d like to suggest that, to a decent extent, we already store green hydrogen and use it to run our trucks. We store this hydrogen in the form of Diesel fuel, so you don’t realize it’s hydrogen.

Much of the oil in the United States these days comes from tar sands and shale. It doesn’t flow well at room temperature, and is too heavy and gooey for normal use. We could distill this crude oil and use only the light parts, but that would involve throwing away a huge majority of the oil. Instead we steam reform it to gasoline, ethylene and other products. The reaction is something like this, presuming an input feed of naphtha, C10H8:

C10H8 + 2 H2O –> C7H8 + C2H4 + CO2.

The C2H4 component is ethylene. We use it to make plastics. The C7H8 is called toluene. It is a component of high octane gasoline (octane rating about 114). The inventor of the process, Eugene Jules Houdry claimed to have won WWII for the allies because his secret process (Houdryflow catalytic cracking) allowed high production of lots of gasoline of very high octane, giving US and British planes and trucks higher mpg than the Germans or Japanese had. It was a great money maker, but companies can make even more by adding hydrogen.

Schematic of the hydrocracking process, from the US energy information agency

Over the last 2-3 decades, refineries have been adding catalytic hydrogenation processes. These convert high octane aromatic products, like toluene to low -octane diesel and jet fuel. These products sell for more. Aromatic toluene is exposed to hydrogen at about 500°C and 300 psi (20 bar) to produce heptane, an excellent diesel fuel with about 7% more energy content than toluene per gallon.

C7H8 + 4H2 –> C7H16.

Diesel fuel sell for about 20% more than gasoline per gallon, in part because of the higher energy content, and because Diesel engines are more efficient than gas engines. What’s more, toluene expands as it’s converted to heptane. One gallon of toluene converts to 1.16 gallons of heptane. As a result hydrogenation adds about 40% to the sales price per molecule. Refineries have found that they can make significant money this way if they can buy cheap hydrogen. Over the last few years, several refineries in Norway and Texas (high sun and wind areas) have added hydrogenators along with electrolysis units to produce the cheap hydrogen when no one needs the unwanted electricity generated when supply exceeds demand. Here is an analysis of the thermodynamics of this type of hydrogen generation.

Robert Buxbaum, May 11, 2023

Of walking sticks, canes, scepters, and wands.

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Franklin’s walking stick, willed to General Washington. Now in the Smithsonian.

Many famous people carried walking sticks Washington, Churchill, Moses, Dali. Until quite recently, it was “a thing”. Benjamin Franklin willed one, now in the Smithsonian, to George Washington, to act as a sort of scepter: “My fine crab-tree walking stick, with a gold head curiously wrought in the form of the cap of liberty, I give to my friend, and the friend of mankind, General Washington. If it were a Scepter, he has merited it, and would become it. It was a present to me from that excellent woman, Madame de Forbach, the dowager Duchess of Deux-Ponts”. A peculiarity of this particular stick is that the stick is uncommonly tall, 46 1/2″. This is too tall for casual, walking use, and it’s too fancy to use as a hiking stick. Franklin himself, used a more-normal size walking stick, 36 3/8″ tall, currently in the collection of the NY Historical Society. Washington too seems to have favored a stick of more normal length.

Washington with walking stick

Walking sticks project a sort of elegance, as well as providing personal protection. Shown below is President Andrew Jackson defending himself against an assassin using his walking stick to beat off an assassin. He went on to give souvenir walking sticks to friends and political supporters. Sticks remained a common political gift for 100 years, at least through the election of Calvin Coolidge.

Andrew Jackson defends himself.

I started making walking sticks a few years back, originally for my own use, and then for others when I noticed that many folks who needed canes didn’t carry them. It was vanity, as best I could tell: the normal, “old age” cane is relatively short, about 32″. Walking with it makes you bend over; you look old and decrepit. Some of the folks who needed canes, carried hiking sticks, I noticed, about 48″. These are too tall to provide any significant support, as the only way to grasp one was from the side. Some of my canes are shown below. They are about 36″ tall, typically with a 2″ wooden ball as a head. They look good, you stand straight, and they provides support and balance when going down stairs.

Some of my walking sticks.

I typically make my sticks of American Beech, a wood of light weight, with good strength, and a high elastic modulus of elasticity, about 1.85 x106 psi. Oak, hickory, and ash are good options, but they are denser, and thus more suited to self-defense. Wood is better than metal for many applications, IMHO, as I’ve discussed elsewhere. The mathematician Euler showed the the effective strength of a walking stick does not depend on the compressive strength but rather on elastic constant via “the Euler buckling equation”, one of many tremendously useful equations developed by Leonhard Euler (1707-1783).

For a cylindrical stick, the maximum force supported by a stick is: F = π3Er4/4L2, where F is the force, r is the radius, L is the length, and E is the elastic modulus. I typically pick a diameter of 3/4″ or 7/8″, and fit the length to the customer. For a 36″ beech stick, the buckling strength is calculated to be 221 or 409 pounds respectively. I add a rubber bottom to make it non–scuff and less slip-prone. I sometimes add a rope thong, too. Here is a video of Fred Astaire dancing with this style of stick. It’s called “a pin stick”, in case you are interested because it looks like a giant pin.

Country Irishmen are sometimes depicted with a heavy walking stick called a Shillelagh. It’s used for heavier self-defense than available with a pin-stick, and is generally seen being used as a cudgel. There are Japanese versions of self defense using a lighter, 36″ stick, called a Han-bo, as shown here. There is also the wand, as seen for example in Harry Potter. It focuses magical power. Similar to this is Moses’s staff that he used in front of Pharaoh, a combination wand and hiking stick as it’s typically pictured. It might have been repurposed for the snake-on-a-stick that protects against dark forces. Dancing with a stick, Astaire style, can drive away emotional forces, while the more normal use is elegance, and avoiding slips.

Robert Buxbaum, April 20, 2023.

Rotating sail ships and why your curve ball doesn’t curve.

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The Flettner-sail ship, Barbara, 1926.

Sailing ships are wonderfully economic and non-polluting. They have unlimited range because they use virtually no fuel, but they tend to be slow, about 5-12 knots, about half as fast as Diesel-powered ships, and they can be stranded for weeks if the wind dies. Classic sailing ships also require a lot of manpower: many skilled sailors to adjust the sails. What’s wanted is an easily manned, economical, hybrid ship: one that’s powered by Diesel when the wind is light, and by a simple sail system when the wind blows. Anton Flettner invented an easily manned sail and built two ships with it. The Barbara above used a 530 hp Diesel and got additional thrust, about an additional 500 hp worth, from three, rotating, cylindrical sails. The rotating sales produced thrust via the same, Magnus force that makes a curve ball curve. Barbara went at 9 knots without the wind, or about 12.5 knots when the wind blew. Einstein thought it one of the most brilliant ideas he’d seen.

Force diagram of Flettner rotor (Lele & Rao, 2017)

The source of the force can be understood with help of the figure at left and the graph below. When a simple cylinder sits in the wind, with no spin, α=0, the wind force is essentially drag, and is 1/2 the wind speed squared, times the cross-sectional area of the cylinder, Dxh, and the density of air. Multiply this by a drag coefficient, CD, that is about 1 for a non-spinning cylinder, and about 2 for a fast spinning cylinder. FD= CDDhρv2/2.

A spinning cylinder has lift force too. FL= CLDhρv2/2.

Numerical lift coefficients versus time, seconds for different ratios of surface speed to wind speed, a. (Mittal & Kumar 2003), Journal of Fluid Mechanics.

As graphed in the figure at right, CL is effectively zero with sustained vibrations at zero spin, α=0. Vibrations are useless for propulsion, and can be damaging to the sail, though they are helpful in baseball pitching, producing the erratic flight of knuckle balls. If you spin a cylindrical mast at more than α=2.1 the vibrations disappear, and you get significant lift, CL= 6. At this rotation speed the fast surface moves with the wind at 2.1 times the wind speed. That is it moves significantly faster than the wind. The other side of the rotor moves opposite the wind, 1.1 times as fast as the wind. The coefficient of lift lift, CL= 6, is more than twice that found with a typical, triangular, non-rotating sail. Rotation increases the drag too, but not as much. The lift is about 4 times the drag, far better than in a typical sail. Another plus is that the ship can be propelled forward or backward -just reverse the spin direction. This is very good for close-in sailing.

The sail lift, and lift to drag ratio, increases with rotation speed reaching very values of 10 to 18 at α values of 3 to 4. Flettner considered α=3.5. optimal. At this α you get far more thrust than with a normal sail, and you can go faster than the wind, and far closer to the wind than with any normal sail. You don’t want α values above 4.2 because you start seeing vibrations again. Also more rotation power is needed (rotation power goes as ω2); unless the wind is strong, you might as well use a normal propeller.

The driving force is always at right angles to the perceived wind, called the “fair wind”, and the fair wind moves towards the front as the ship speed increases. Controlling the rotation speed is somewhat difficult but important. Flettner sails were no longer used by the 1930s because fuel became cheaper and control was difficult. Normal sails weren’t being used either for the same reasons.

In the early 1980s, there was a return to the romantic. Famous underwater explorer, Jacques Cousteau, revived a version of the Flettner sail for his exploratory ship, the Alcyone. He used aluminum sails, and an electric motor for rotation. He claimed that the ship drew more than half of its power from the wind, and claimed that, because of computer control, it could sail with no crew. This claim was likely bragging, but he bragged a lot. Even with today’s computer systems, people are needed to steer and manage things in case something goes wrong. The energy savings were impressive, though, enough so that some have begun to put Flettner sails on cargo ships, as a right. This is an ideal use since cargo ships go about as fast as a typical wind, 10- 20 knots. It’s reported that, Flettner- powered cargo ships get about 20% of their propulsion from wind power, not an insignificant amount.

And this gets us to the reason your curve ball does not curve: it’s likely you’re not spinning it fast enough. To get a good curve, you want the ball to spin at α =3, or about 1.5 times the rate you’d get by rolling the ball off your fingers. You have to snap your wrist hard to get it to spin this fast. As another approach, you can aim for α=0, a knuckle ball, achieved with zero rotation. At α=0, the ball will oscillate. It’s hard to do, but your pitch will be nearly impossible to hit or catch. Good luck.

Robert Buxbaum, March 22, 2023. There are also Flettner airplane designs where horizontal, cylindrical “wings” rotate to provide high lift with short wings and a relatively low power draw. So-far, these planes are less efficient and slower than a normal helicopter. The idea could bear more development work, IMHO. Einstein had an eye for good ideas.

Plans to Raise-the-Dead-Sea

2 Replies

The Dead Sea in Israel is a popular tourist attraction and health resort-area. It is also the lowest point on the planet, with a surface about 430m below sea level. Its water is saturated with an alkaline salt, and quite devoid of life, and it’s shrinking fast, loosing about 1 m in height every year. The Jordan river water that feeds the sea is increasingly drawn off for agriculture, and is now about 10% of what it was in the 1800s. The Dead Sea is disappearing fast, a story that is repeated with other inland seas: the Aral Sea, the Great Salt Lake, etc. In theory, one could reverse the loss using sea water. In theory, you could generate power dong this too: 430m is seven times the drop-height of Niagara Falls. The problem is the route and the price.

Five (or six) semi-attractive routes have been mapped out to bring water to the Dead Sea, as shown on the map at right. The shortest, and least expensive is route “A”. Here, water from the Mediterranean enters a 12 km channel near Haifa; it is pumped up 50m and travels in a pipe for about 52 km over the Galilean foothills, exiting to a power station as shown on the elevation map below. In the original plan the sea water feeds into the Jordan river, a drop of about 300m. The project had been estimated to cost $3 B. Unfortunately, it would make much of the Jordan river salty. It was thus deemed unacceptable. A variation of this would run the seawater along the Jordan in a pipe or an open channel. This would add to the cost, and would likely diminish the power that could be extracted, but you would not contaminate the Jordan.

A more expensive route, “B”, is shorter but it requires extensive tunneling under Jerusalem. Assuming 20 mies of tunnel at $500 MM/mile, this would cost $10B. It also requires the sea water to flow through the Palestinian West Bank on its way to the sea. This is politically sensitive and is unlikely to be acceptable to the West Bank Palestinians.

Vertical demand of the northern route

Two other routes, labeled “C” and “D” are likely even more expensive than route B. They require the water to be pumped over the Judaean hills near Bethlehem, south of Jerusalem. That’s perhaps 600m up. The seawater would flow from Ashkalon or Gaza and would enter the Dead Sea at Sodom, near Masada. Version C is the most politically acceptable, since it’s short and does not go through Palestinian land. Also, water enters the dead sea at its saltiest point so there is no disruption of the environment. Route D is similar to C, somewhat cheaper, but a lot more political. It goes through Gaza.

The longest route, “E” would go through Jordan taking water from the Red Sea. Its price tag is said to be $10 B. It’s a relatively flat route, but still arduous, rising 210m. As a result it’s not clear that any power would be generated. A version of this route could send the water entirely through Israel. It’s not clear that this would be better than Route C. Looking things over, it was decided that only routes that made sense are those that avoided Palestinian land. An agreement was struck with Jordan to go ahead with route D, with construction to begin in 2021. The project has been on hold though because of cost, COVID, and governmental inertia.

In order to make a $5-10B project worthwhile, you’ll have to generate $500MM to $1B/year. Some of this will come from tourism, but the rest must come from electrical power generation. As an estimate of power generation, let’s assume that that the flow is 65 m3/s, just enough to balance the evaporation rate. Assuming a 400 m power drop and an 80% efficient turbine, we should generate 80% of 255 MWe = about 204 MWe on average. Assuming a value of electricity of 10¢/kWh, that translates to $20,000/ hour, or $179 million per year. This is something, but not enough to justify the cost. We might increase the value of the power by including an inland pond for water storage. This would allow power production to be regulated to times of peak load, or it could be used for recreation, fish-farming, or cooling a thermal power station up to 1000 MWe. These options almost make sense, but with the tunnel prices quoted, the project is still too expensive to make sense. It is “on hold” for now.

It’s not like the sea will disappear if nothing is done. With 10% of the original in-flow of water to the Dead Sea, it will shrink to 10% its original size, and then stop shrinking. At that point evaporation will match in-flow. One could add more fresh water by increasing the flow from the sea of Galilee, but that water is needed. When more water is available, more is taken out for farming. This is what’s happened to the Arial Sea — it’s now about 10% the original size, and quite salty.

Elon Musk besides the prototype 12 foot diameter tunnel.

There’s a now a new tunnel option though and perhaps these routes deserve a second look: Elon Musk claims his “Boring company” can bore long tunnels of 12 foot diameter, for $10-20 MM/mile. This should be an OK size for this project. Assuming he’s right about the price, or close to right, the Dead Sea could be raised for $1B or so. At that price-point, it makes financial sense. It would even make sense if one built multiple seapools, perhaps one for swimming and one for energy storage, to be located before the energy-generating drop, and another for fish after. There might even be a pool that would serve as coolant for a thermal power plant. Water in the desert is welcome, even if it’s salt water.

Robert Buxbaum, February 14, 2023.