Tuesday, October 18, 2016

For Purely Technical Reasons

Cedric Sacilotto
It is tempting for us to think that our technological choices—whether we choose to live in a city, a suburb or out in the country; whether we want to drive a pick-up truck, a gasoline-electric hybrid or ride a bicycle; whether we take a train, drive long distances or fly—are determined by our tastes. We may flatter ourselves that we are in control, and that our choices are reflective of our enlightened, environmentally conscious values. This view rests on a foundation of circular reasoning: we behave in enlightened ways because we are enlightened, and we are enlightened because, to wit, we behave in enlightened ways. As to why what we consider enlightened is in fact enlightened rather than a question of possibly questionable personal taste—that is not to be discussed: de gustibus non est disputandum.

But there is an alternative viewpoint, which seems more realistic in many ways, because it rests on a foundation of physical, technical specifics rather than fickle and arbitrary consumer preference, whim or taste. From this viewpoint, our technology and associated lifestyle choices are dictated by the technical requirements of their underlying technologies, both physical (the operation of the energy industry, the transportation industry, etc.) and political (the operation of political machines that segregate society by net worth and income, relegating wage-earners to a global disenfranchised underclass).

A few years ago I found out that I needed to replace the diesel engine on my boat (the old one blew up definitively) and looked at a number of options, one of which was to replace it with an electric motor and a large bank of batteries. The electric option was touted as being quiet, non-polluting, and having just enough range to get in and out of the marina and to get back to dock if the wind died during a typical daysail. It turned out to be more than twice as expensive as a replacement diesel engine. As to what one might do to take such a boat any great distance (that involves many hours of motoring) the solution is to… add a diesel engine hooked up to a very large alternator, at triple the cost of just replacing the diesel. And so I just replaced the diesel.

Diesel engines have a lot of positive qualities: they can run continuously for tens of thousands of hours; they can be rebuilt many times just by replacing the bearings, the cylinder sleeves, the piston rings and the valves; they are exceptionally reliable; the fuel they use is energy-dense. For these reasons, they are found throughout freight and construction industries and are used for small-scale power generation. They can be very large: the larger ships have engines that are as big as houses, with ladders welded to their cylinder walls, so that servicemen can climb down into them to service them after the cylinder head and the piston assembly are pulled out using an overhead shop crane. Small diesel engines make a lot less sense, and the silliest of them are the ones found on small yachts. There are many aspects of their design that make them silly, but there is also an overriding reason: they use the wrong fuel.

You see, diesel is a precious commodity, used in the transportation industry (by trucks, locomotives and ships), and in construction equipment, with no alternative that is feasible. A cousin of diesel fuel is jet fuel—another petroleum distillate—that is used to power jet engines, again, with no alternative that is feasible. And then there is a fuel that is only really useful as a small engine fuel: gasoline, that is. Gasoline engines beyond a certain size become much more trouble than they are worth.

Each barrel of crude oil can be distilled and refined into a certain amount of diesel and jet fuel, a certain amount of gasoline, some tar and some far less useful substances such as naphtha. The diesel is spoken for, because it literally moves the world; but if enough small engines cannot be found to burn all the gasoline that is produced, it becomes a waste product and has to be flared off at the oil refinery, at a loss. Indeed, prior to Henry Ford coming up with the brilliant plan to build cars cheap enough for his workers to afford, gasoline was dumped into rivers just to get rid of it, because while everyone burned kerosene (a distillate, like jet fuel and diesel) in lamps, cars remained playthings of the rich, and there simply wasn’t a market for any great quantities of gasoline.

Therefore, it became very important to find ways to sell gasoline, by finding enough uses for it, no matter how superfluous they happened to be. And although some people think that the private automobile is a symbol of luxury and freedom and feel the thrill of the open road, the reason they think that is because these ideas were implanted in their heads by the people who were tasked with finding a market for gasoline. Alongside cars, great effort was put into marketing all sorts of other small engines: for lawn mowers, jet skis, motorcycles, ATVs, boat outboard motors… The only semi-industrial use of gasoline is in chainsaws, small generators and air compressors, service and delivery vehicles, and outboard engines.

And so people were sold on the idea of driving their own car, whether they needed to or not, and spending lots of time stuck in traffic—all so that they would pay for gasoline. By causing all that excess traffic congestion, they also created the need to widen roads and highways, generating demand for another borderline useless petroleum product: road tar. And since there was a problem with cramming all these cars into cities (where cars are generally not needed if the cities are laid out using proper urban design, with sufficient numbers of tram, light rail and subway lines, etc.) the solution was to move everybody out to the suburbs. And so the reason half of the US population now lives in suburbia and drives has nothing to do with their needs, and everything to do with the need to sell them gasoline.

Some people may react negatively to the idea that their suburban castle and their magic chariot are all just part of a plan to make them spend much of their life paying for the right to dispose of toxic waste in unsafe ways. Rest assured, their preprogrammed negative reaction is part of the plan. Every effort has been made to program people to think that this waste disposal job—carried out at one's own expense—is, in fact, something that should be considered a sign of success. The most efficient way to motivate a slave to perform is to convince him that he is free. To this end, driving is celebrated in music and film and portrayed as a way of life. Calling it what it is—being a slave to a machine—is bound to cause cognitive dissonance, all the more so because driving a lot destroys one's mind: in the immortal words of a character from the movie Repo Man, ”The more you drive, the less intelligent you become.” In this respect, most of the people living in the US are far past the point of no return, and it is pointless to attempt to impart to them any ideas that are discordant with the dead-end lifestyle into which they have been unconsciously coerced.

Getting back to electric vehicles, such as what my boat would have ended up if I were gullible and made of money: they are obviously a defective idea. Their range is limited, they take longer to charge than it takes to fill a gas tank, and they use expensive and dangerous lithium-ion batteries that need periodic replacement. There is not enough lithium available to continue making batteries for laptops and smartphones (which periodically burst into flames), never mind providing for a giant expansion of battery-building to support lots of electric cars. Perhaps most importantly, they shrink the market for gasoline. So, what’s the reason behind the push?

It certainly isn’t part of any particular effort to electrify transportation in general, because no electric solution exists for ships or planes, and electrifying rail freight is an impossibly expensive proposition. It certainly isn’t part of an effort to cut greenhouse gas emissions, because most of the ways electricity is currently generated is by burning coal and natural gas—and will be, while supplies last, because electricity is hard to store, and no matter how many solar arrays and wind farms are installed something will be needed to power the electric grid on overcast, windless days.

No, the push for electric cars is motivated by a different sort of technology—political technology. You see, the oil age is drawing to a close. Last year the oil companies only discovered 1 barrel of oil for every 10 barrels they produced; at the turn of the century it was closer to 1 for every 4. At the same time, most of the easy-to-get-at oil has already been produced, and now it takes 1 barrel’s worth of energy to produce something like 10 barrels, whereas at the dawn of the age of oil it was closer to 1 for every 100 barrels. Such a low level of net energy production is turning out to be insufficient to maintain an industrial civilization, and as a result economic growth has largely stalled out. And although large investments in oil production have succeeded in keeping large volumes of oil flowing, for now, this is turning out to be an ineffective way to invest money, with many energy companies, once so profitable, now unable to pay the interest on their debt. And even though constant injections of free money are currently keeping developed economies from cratering into bankruptcy, it has been clear for some time that each additional dollar of debt produces significantly less than a dollar’s worth of economic growth. Growing debt within a growing economy can be very nice; but if the economy isn’t growing as fast, it’s fatal.

As the oil age winds down, personal transportation, in the form of the automobile, is bound to once again become a plaything of the very rich. But then, when it comes to electric cars, it already is! And I don’t mean Tesla: the most commonly used electric vehicle worldwide is the golf cart. And who uses golf carts? Members of golf clubs; guests at resorts; residents of posh gated communities; employees at corporate and academic campuses… And what do all these people have in common? They are all members of the salaried elite; they are definitely not members of the wage-earning class. To them, the electric car offers a way of preserving a semblance of the status quo for themselves while setting themselves apart (in their own minds) from all of the gasoline-burning riffraff. Let the great unwashed in the flyover states, with their pickup trucks complete with gun racks, burn what’s left of the gasoline while overdosing on synthetic opiates while the salaried elites and individuals of high net worth, ensconced in their campuses and gated communities, will create a different future for themselves, replete with wind turbines, solar panels and electric cars (until they all get shot by all those they have disenfranchised).

20 comments :

Jordi C. said...

I get your point Dmitry, but are you sure about the lithium? Lithium batteries use only 4% by mass of lithium.

With an energy density of 500Wh/kg we're talking about 80 grams of lithium per Kw-h, lets round this to 0.1Kg.

We have in earth about 1.3x10^10 kg of lithium, thats about 13x10^10Kw-h of maximum storage that we can create, our current use is.. (132x10^14Kw) well, we are fucked, it seems like even with all renovables we will have to kill some % of the poorer. Soon™

NowhereMan said...

Great post this week Dmitry. That last paragraph in particular sums up the yawning gulf between the effete liberal left allegedly represented by the HRC crowd and the old-school working class right allegedly represented by Donald Trump. Never mind that neither actually represents in any meaningful way the crowd for whom they carry the flag, the cognitive dissonance for both is palpable and based on the fact that neither has any solutions for the energy realities that actually face their constituents. Of the two, I think continued reliance on gas driven automobiles is at least the most honest, as most of these people (especially in the American west) have at the behest of American society, committed themselves to lives of long distance commutes which would otherwise simply not be possible at all. For most of those born into the population saturated post baby boomer world of 1970 or later, there simply were no realistic alternatives. In contrast, the electric vehicle boom of recent vintage was, is, and will remain a product of marketing hype, and as you correctly noted, barely concealed elitism. Questioning the underlying cultural paradigm of mindless consumerism and waste dedicated to the care and feeding of the capitalist technological machine is simply never considered at all. But whether we like it or not, that world of 20th century industrialism and exponential growth is crashing down around us now as we speak, and no amount of "green" technological magic is ever going to stop it. The next 5 years will be pivotal, as the western rejection of AGW and the limits to growth as "politically actionable" events will almost certainly chart our course for the remainder of the century.

ffm said...

Dmitry, brilliant article. But I need help in getting rid over a thought which I can't make go away. Consider that any transformation of energy from one medium to another occurs with an efficiency of less than one. For simplicity let's choose decimal 5. Then the conversion of petro to mechanical would mean that 100 unit of petrol in your tank converts to 50 units of wheel energy. Likewise at the generator 100 units of petrol yields 50 units of electric energy. The 50 units of electric energy yields 25 units of wheel energy. Thus one obtains twice as much wheel energy by sourcing energy from the tank as opposed the the battery. One can pick at detail of the particular efficiency factors involved. But the that does not obviate the fundamental concept regarding the greater energy wastage of two step versus one step conversions. And it entirely sidesteps the total factors of production costs (which must be included for any argument to be taken seriously-example two step processes have larger total factors).

I must be wrong somewhere. Please someone help me. Otherwise I must be left fighting off the idea that our entitled , morally superior and wiser elite are in fact increasing rather than decreasing energy use via their choice of a two step process.

AlaBikeDr said...

A novel reflection. Most of my tech choices are to retain the value in what I already own. I buy a car to get to the house I own and the job I happen to have. I buy a generator to prevent losing the meat in the freezer. I replace my computer because I am used to being entertained on the internet. I periodically consider some solar panels just for fun to play at being environmentally sensitive since I really am but it never makes sense because I have trees which "solar protect" my house. I could cut down one of my oaks and get enough wood to heat my home for maybe 5 years but I only have 5 trees. My most recent purchase is a mattress and insurance, purchases that don't seem very technological. I have never needed a diesel engine and just rely on them to bring me things. When they don't or can't, I'll consider getting one to go get what I need and keep the value in what I have...

postpeakmedicine said...

You're right about electric cars - most of the people who enthuse about them have probably never driven one and don't know their limitations. We own one (a Nissan Leaf) and we are very pleased with it, but we have very unusual requirements, and I wouldn't recommend one for most "normal" people. We live on the Isle of Man, a tiny island in the Irish Sea, 32 miles long and 14 miles wide, and our main requirement is that it can get us to the furthest point on the island and back home again. The range is 90 miles which is just about enough to do that, but not much more, and we would be foolish to take it on a longer trip off island. It takes a whole night to charge up at "normal" rate, although it is possible to get a faster charger. The main requirement for owning an electric car (in my view) is to have a strong marriage, because periodically one of us forgets to plug it in the night before, with predictable results ("I thought you plugged it in!" "No, I thought you plugged it in!" "How am I going to to get to work?"). So far we haven't divorced over it but just give it time. Apart from that, it costs almost nothing to run (if you ignore the cost of buying it in the first place) and when the oil runs out, it could conceivably be charged from PV panels, although I suspect this would take a week rather than overnight. It's not going to replace the gasoline car any time soon.

forrest said...

There is another reason, a direct societal reason for a limp economy:

Massive wealth transfer to the [pretty-tiny]% leaves everyone who actually needs stuff with no purchasing power, so that it doesn't pay for the monied to sink their loot into producing anything. Government-abetted ponzi schemes are not limited to rates of return achievable in any conceivable real-world scam, so they suck out the bulk of human talent. Even if we found essentially unlimited energy sources, that would be the case.

You're saying we've now used up so much energy that we couldn't get up an economy up even if we sorted out the human dysfunctioning (like all the fuels we've been burning just killing ISIS in Iraq while killing their enemies in Syria)?

What about the space-based solar stuff that Gerard O'Neill & his MIT engineering class concluded was immediately doable, back in the 1980's? Politically, we'd rather shoot ourselves in the ouch, but wouldn't that still be technically possible?

Robo said...

Although I've always been aware that asphalt comes from the bottom of the barrel, it's a real revelation to learn that gasoline is also a troublesome byproduct of the more profitable petroleum distillates. Happy Motoring explained!

Whilst confirming this information I also discovered that John D. Rockefeller of Standard Oil was one of the earliest Industrial Age conservationists. Who would have guessed?

My thanks to you for yet another another perceptual shift.

Cortes said...

Fascinating as ever.

One suggestion for any amended version in a future collection of essays would be to acknowledge the increasing use of electrically powered "mobility scooters " by the aged or infirm and, regrettably, by the bone idle of all ages. As they zip along pavements (US - sidewalks) they put pedestrians in danger with their antics.

Pyotr said...

Yes this progression is just how we are 'managed' Mr Orlov. However I must nag you just a little: When I was a young man I remember fitting a regulator to my cars induction system and running it on bottled gas. Even now here in the UK cars are fitted with LP gas tanks; though filling stations that service these are few and far between.

Don Stewart said...

Dmitry
I always enjoy your posts. On this one, however, I think you are not seeing all of the picture. I call your attention to this quote:

'But there is an alternative viewpoint, which seems more realistic in many ways, because it rests on a foundation of physical, technical specifics rather than fickle and arbitrary consumer preference, whim or taste. ‘

In the book The Mind-Gut Connection, Emeran Mayer describes our mind as containing a vast number of memories, sort of like YouTube clips, which contain information about how our body reacted in those circumstances. Including how our gut reacted. Now consider the well-known YouTube clip of a crow sliding down an ice slick roof. The crow finds it to be fun, and flies back up to the top to repeat the process several times. We can speculate that the crow finds the combination of effortless movement, speed, and the mental stimulation of being on the edge between control and out of control to be pleasant. Now consider an All Terrain Vehicle. The sensations of the human driver are, I think, similar. If a crow could physically drive an ATV, I would expect to see them blasting around the desert and over sand dunes by the sea. We should not be surprised at the similarities to human reactions. Mayer describes how, 30 years ago, he published a paper with the title ‘Are Gut Peptides the Words of a Universal Biological Language?’ We now know that he was essentially correct. Many of the same hormones which influence human behavior were invented by microbes.

I don’t disagree that gasoline was a waste product, and that capitalism found a use for it in automobiles and other appliances. But the appliances themselves are not created just to burn up gasoline. They are designed to stimulate certain hormonal reactions in humans, while using the waste products that industrial society creates.

And Madison Avenue and Global Corporations are not the masters at manipulating subjects. For example, on page 85 of Mayer’s book, he recounts Robert Sapolsky’s telling of the remarkable ability of ‘an evil but clever microorganism named Toxoplasma gondii.’ I won’t try to retell the story here. Suffice to say that the pharmaceutical industry has spent billions trying to duplicate the same tasks that the microbe performs effortlessly.

It is not impossible for a wise brain to move a human body in a better direction. For example, I recently heard two MDs describe their revulsion at the junk food served at medical meetings. But since the junk food companies are masters at manipulating the ‘universal language’, we should have few illusions about how easily a whole society might learn to experience that same revulsion.

Don Stewart

Paul Olsen said...



Dimitri I have to take exception to some of your arguments here.

The % gasoline that can be produced from crude oil in modern refineries can be adjusted to market demands. The technology is as old as world war II when it was required to maximize production of aviation grade fuel. Using processes of cracking and alkylation refineries can extract almost any mix they wish from crude. From wiki: "Modern refinery operation can be shifted to produce almost any fuel type with specified performance criteria from a single crude feedstock."

Furthermore for the great majority of us who are not nautically oriented the freedom of transportation,particularly in the US, where at the spur of the moment you can go for a six pack at the nearest watering hole 10 mi away in your F150 at 11:00 PM is treasured more than anything except basic sustenance . even more than guns. I dont think its such a bad thing but agree it has to be and can be done in a sustainable green fashion

I dont think when push comes to shove most people (other than the elite) care about what fuel or kind of engine they are using as long as they get the performance they have come to expect. Yes there will be disruptions and reconditioning which will cause some demonstrations, but you mess with the basic right and you will see a revolution.




Mister Roboto said...

The advent of gasoline-utilizing automotive engines solved another noisome problem of the the era: Big cities such as New York, Boston, and Philadelphia were having an increasingly difficult time managing all the horse manure that was produced by the pre-automotive means of transport, namely the horse-drawn carriage. My understanding is that it was getting so bad that this former means of transport was on the verge of becoming nonviable as it was.

jessi thompson said...

You are absolutely right that financial pressures limit choices. I personally like the viewpoint that we can all lower our footprint by embracing "voluntary poverty" or choosing to do without certain things for the greater good. Granted, the type of person who is willing to do that is rare.

About the diesel engine, I have heard that the diesel engine was originally invented and designed with farmers in mind, and that the original diesel engines were made to run on agricultural waste, basically large amounts of plant matter. Which brings me to my second point, you did not mention one of your other options: biodiesel.

I know you are the type of person who does extensive research on engineering requirements before making a decision, and you may have already considered biodiesel to be unfeasible for other reasons. I don't know enough about engines, to tell you the truth. What I have heard about biodiesel is you can either adapt the engine to burn plant based oil (used french fry oil, for example), kits to modify cars run in the range of a couple hundred dollars (or did, when I looked into it 5 years ago or so). The other way is to take your waste product (say, used french fry oil) and turn it into diesel fuel yourself, but this requires the ability to safely handle things like lye and methanol, so a good background in basic chemistry and fire safety is necessary, along with the necessary research, of course. Obviously, boat engines are different than car engines (most of the time), and I have no idea if this will meet your needs.

For anyone interested in biodiesel, running biodiesel is cleaner than using an electric car hooked up to the grid because all the carbon it burns is carbon that is already circulating through the carbon cycle, it is not the fossil carbon that is adding greenhouse gasses. Best of luck, and thank you for pointing out that while most of us operate under the illusion that we have perfect freedom of choice, in reality all our choices are restricted by our own personal financial means and the particular place and time where we find ourselves. Much as we want to, many of us simply cannot afford to just buy a plot of land and then live off it. I think we all need to stop judging each other and meet people where they are, and embrace simple, small improvements that are suitable for each individual.

Jean L said...

Dmitry, I've read and taken lots of notes on your books, The Five Stages of Collapse and Reinventing Collapse and appreciate your insights and experiences. Thank you.

I find this post to be a little much. You speak almost disdainfully about gasoline-powered cars as if drivers have been manipulated to consume a petroleum waste product, yet you use a diesel-fueled boat. You want to ride around in the water while other people prefer to ride around on land. Why are car owners manipulated dupes while boat owners are not? In both cases, people want to move around the face of the earth. Is gliding over the water superior to cruising on land? They're both fun and I'm grateful for both!

Carlos Alberto Florez Cárdenas said...

The truth is that I think the science has advanced far enough to put aside all filthiness, but now is not viable for companies, would lose a lot of money, others disappear, etc ...

Walter said...

ffm - The closer you are to "point of flame," the more efficient your power source. Thus an old Honda Accord is more efficient than a new Nissan Leaf.

Lee said...

Every silver lining has a dark cloud.

As far as fuel to power a survival boat goes, have you considered alcohol. It can be made out of anything with sugar or starch in it. Sugar beets, rotten fruit, barley and etc. And the stuff left over makes excellent pig food. It would also make a safer cooking fuel for use in a boat.

The problem with alcohol is --- it absorbs water. In that case it could be re-distilled.

Also the batteries in portable devices are more unstable and have shorter lifespans than Lithium Iron Phosphate batteries. I undercharge my LiFePo4 batteries and they have remained exactly in balance for 3 years without the use of battery management systems. They haven't lost any capacity that I can detect either.

And whats wrong with golf carts anyway. As a landlubber, I would prefer one to a feckin horse. Gulf carts don't bite, kick, panic, draw flies and hang out eating when not in use.

An electric outboard, alcohol powered generator, solar cells and a small battery bank of LifePo4 batteries might work well with your new boat. But it won't be perfect.

Perfect is just a concept.



MoonShadow said...

@ffm...

The actual energy conversion coefficients are closer to...

35% to 40% for a modern, gasoline fueled, spark ignition engine. That's to the drive train, not the wheels. Closer to 30% for an automatic transmission to the wheels, better for a manual transmission.

45% to 60% for a modern, diesel fueled, compression ignition engine. Also to the drive train, not the wheels. Typically, the larger the power rating of the engine, and the closer that the engine can be kept to it's peak efficiency, the higher the real world efficiency is. Which has a lot to do with why they are great for large, consistent power applications; such as capital ships & freight trains. There are some, older, very slow speed diesel engine designs that are very efficient as well; such as the single cylinder Lister 6/1, but they are huge for their peak power output. The Lister 6/1 stands 36 inches tall and weighs over 800 pounds, but produces a max power of 6 horsepower at the shaft. They do last forever, though, so they are really only used for remote power generation.

However, the energy conversion for rechargable batteries; grid power in, charging, then battery power out to the electric motor; is closer to 80%. That doesn't include the electric motor's own efficiency, but those are typically over 96% efficient across their torque range, and most electric drivetrains don't require a transmission, so we can effectively ignore that.

To give you an idea of a proxy for energy loss due to inefficiency, measure the reject heat each system makes. Gas engines have so much waste heat, that no supplemental heat is required in winter anywhere in the US except Alaska. Even large diesel trucks need additional heat, or cover their radiators, during winter. And electric vehicles not only require an electric cabin heater, they don't have cooling systems at all.

None of this means that I disagree with Dmitry about the realistic future of electric cars, though. Electric cars simply move the environmental problem from the roads to the power plants, and gasoline is still cleaner per kilowatt than coal. Anyone who buys an electric car because they think that they are really helping the environment is deluding themselves. And there isn't enough lithium *OR* lead *OR* nickel to convert the world's fleets of automobiles to any known rechargable technology. And all the other niche technologies are so toxic that, in any other context, they would be illegal.

On a side note, I do disagree with Dmitry on the nature of gasoline as a waste product in our history. Propane was discovered as a waste product of *gasoline* refining, but it most certainly has economic value & use beyond any 'artificial' market demand. Gasoline was a waste product, only because it's uses were not well known yet. Once that knowledge was common, the market developed naturally enough.


Cynthia Quilici said...

Very good, with just one nit to pick: I hate reading about oil "production", and I hope you will consider replacing it in the future with the more accurate word, "extraction": a better mental habit which gives a clearer picture, I think.

@Jean L, there's a big difference in the energy-efficiency/cost per mile of boat engines to move things versus car/truck engines. A regular cargo ship is about 10x more efficient than a tractor-trailer on an equivalent cargo weight basis (~500 miles/gallon/ton), and when you add the nearly-free wind power of sail most of the time, then that fuel expenditure per mile drops quite a bit lower.

One might question the degree to which one should want or need to move at all, but, if one *does* need or want to move, boats are pretty effective.

Wolfgang Brinck said...

Some people have proposed that if there is a pool of energy and multiple processes competing to use up the energy in that pool, the process that is capable of using up the energy fastest will win out. If this thesis is correct, then energy conservation or efficient use of the energy is not the winning strategy but profligate use is. The use of gasoline engines to burn gasoline is a winning strategy over any scheme that would only use diesel fuel and then pump the gasoline back into the ground, assuming that were even feasible.
Of course, once an energy source becomes depleted, the process that was so good at depleting it becomes irrelevant and simply goes away, e.g. the gasoline engine and the culture that depended on it.