Thursday, May 31, 2018

Genuinely New Ideas in Rocketry Are Rare

Vanishingly rare.  I don't know if this is the first time it has ever been discussed, but according to the website, a collaboration between two universities is researching a booster that literally consumes itself on the ascent to orbit. 
In a paper published in the Journal of Spacecraft and Rockets, engineers from the University of Glasgow and Oles Honchar Dnipro National University in Ukraine discuss how they have built, fired, and for the first time throttled up and down an 'autophage' engine which could change how small satellites are sent into space.
'Autophage' translates as 'self-eating', and the concept is that instead of fuel tanks and the superstructure that the booster provides, a vehicle powered by an autophage engine would consume its own structure during ascent.

A typical booster, like the Falcon 9 boosters that SpaceX recovers and reuses, contains liquid fuel and oxidizer tanks along with plumbing to connect those tanks to the booster's nine engines   Big boosters tend to be liquid fueled, with notable exceptions for the large solid rocket boosters used in the Space Shuttle program, and large vehicles like the Delta IV Heavy.  Typically, the booster's weight is several times the weight that can be delivered to orbit.  For every pound of weight added to payload, the vehicle has to carry more fuel, and the fuel to lift that fuel. If the booster's weight was usable fuel that would be an incredible advance. 

The autophage engine concept allows weight from the plumbing tanks and other essentials to go into larger cargo capacity.  If the same technology were to be in upper stages, less debris would survive to make it into space.  No boosters (or less junk) to recover or dump in the ocean; and less debris from upper stages.  More efficient from all perspectives.
The autophage engine consumes a propellant rod which has solid fuel on the outside and oxidiser on the inside. The solid fuel is a strong plastic, such as polyethylene, so the rod is effectively a pipe full of powdered oxidiser. By driving the rod into a hot engine, the fuel and oxidiser can be vaporised into gases that flow into the combustion chamber. This produces thrust, as well as the heat required to vaporise the next section of propellant.

Simply by varying the speed at which the rod is driven into the engine, the researchers have shown that the engine can be throttled – a rare capability in a solid motor. Currently, the team have sustained rocket operations for 60 seconds at a time in their lab tests.
I'm having a difficult time visualizing how this could work.  The vehicle has a "combustion chamber", or chambers, so some structure needs to last the entire time it's burning to hold the combustion chamber and engine nozzle(s) in place.  If some control or telemetry to the ground is involved, that will have to be in the booster just as it is now, and will get thrown away, too.  If the autophage motor is just burning along the length of the body, it's not that different from any solid rocket motor; those tend to burn from the center outward along the entire length of the body.  Having the ability to throttle the engine up and back is unusual.  Solid motors are typically said to burn until they burn out.

The researchers describe it in starkly different terms than I do and don't address my thoughts at all.  Dr. Patrick Harkness, senior lecturer at the University of Glasgow's School of Engineering, puts it this way:


A small autophage motor at the University of Glascow.  University of Glascow photograph.

Wednesday, May 30, 2018

Ignore That Financial Mess in Europe, Roseanne Tweeted Something!

Is it 2006 all over again?  Is the economy truly better or are we just seeing the effects of a few local, isolated actions.

Maybe you didn't see the story that Italy is slipping into a financial crisis, but you might have seen the US stock market dropped about 400 points on the Dow.  Italy is why the Dow dropped.  Tokyo's NIKKEI and Australia's ASX200 were also hit by Italy's troubles yesterday.

At root is the same problem, the same rot affecting every country from US to China; Germany to Greece.
Italy risks careening into a new financial crisis after the Bank of Italy said the country’s leaders could not “disregard” financial constraints and its commitments to Brussels.
Escalating worries that Italians may be poised to take a tougher stand against the euro prompted a round of accusations and finger-pointing among EU officials, including a rare admonishment by Donald Tusk, the European council president, who said EU institutions needed to show “respect to voters” in Italy.
In October of '16, I posted an introduction to some of the players in the mess today, as well as a "keep your eyes out" for things going on Italy.  It centers on the 5S Movement, which began as joke and turned into a populist, "Brexit-like" party movement.  iExit?  The latest issues appear to stem from a need to form a "coalition government" between differing parties and their inability to do so. 
The crisis was set off late last week when the Five Star Movement (M5S) and Lega, which had been attempting to form a government, insisted that the president, Sergio Mattarella, approve their choice for finance minister, Paolo Savona, a fierce critic of the euro. Mattarella vetoed the nomination and the incoming populist government collapsed before it had taken power.

The president appointed a new prime minister, Carlo Cottarelli, a former director at the International Monetary Fund, who was expected to present a list of ministers to Mattarella on Tuesday. The president’s spokesman said after a meeting that the two officials would meet again on Wednesday morning.
Add in that the European Central Bank is struggling to keep control in the country, and you get quite a mess.  Ignazio Visco, chairman of the Bank of Italy, said the country was at risk of losing the “asset of trust” with investors.  On Tuesday the Italian bond spread, a leading indicator of investor concern, rose to its highest level in four years.

Italy is the third largest economy in the European Union, behind Germany and France (and I'm leaving out the UK due to the ongoing Brexit).  If Italy were to collapse or go into a deep economic crash, it threatens the entire EU.  Italy has one of the largest national debts in the world and an unemployment rate over 11%. It's economy is now worse off than it was before 2007. The Italians tried, like everyone else, to borrow and spend their way out of the financial crisis, but they never recovered.

The fundamental problem, as I must have said at least five hundred times in the 2800+ posts of this blog, is that the world is awash in debt.  The total debt in the world now is $164 trillion.  Annual world GDP is in the vicinity of $70 trillion so this is well over two years worth of "all the money in the world" to pay off that debt.  That figure ($164 trillion) is not counting the unfunded liabilities in the world's economies, which currently add about $115 trillion in the US alone, as can be found on the Debt Clock.  Unfunded liabilities shouldn't be counted as debt; we haven't spent that money yet. They're more like a promise to spend in the future, however if we can't meet our liabilities now and can't live with a balanced budget it's reasonable to question where that money will come from. 

In the wake of the "great recession" of 2008, the world's central banks went on a stimulus binge like the world has never seen.  Not just the trillions of dollars created out of thin air here in Quantitative Easings; think of China's bridges to nowhere and ghost cities.  If anything, China has worse economic problems than we do.  All the central banks: the Bank of Japan, the European Central Bank, the Central Bank of China: all of them have created money from nothing. 

The US economy has shown some positive reactions to Trump's tax cuts and the news has been mostly good.  The labor participation rate hasn't improved to any noticeable extent since the middle of Obama's second term, though, still on par with the rate in 1978, and I honestly don't know what's up with that since we keep hearing about record low unemployment and other good news.  I note that some aspects of the Dodd-Frank banking regulation bill have been cancelled.  I personally never heard anything good about Dodd-Frank from any financial writer who seems to know the industry, so I view that as good. 

The world, I believe is in a precarious position economically.  Am I just a "too small thinker" to live with a world that measures debt in the hundreds of trillions pf dollars?  Could be.  On the other hand, I don't believe we're immune to any form of economic problems, and I still believe what can't go on forever won't go on forever, because I still believe that infinity is a very handy concept in math and science, but a rotten way to run an economy.

As for when this may happen, I've given up on guessing.  I've posted so many "real soon now" warnings in the life of the blog that I think decorum tells me I should say no one can predict it.

Italian actor and comedian Beppe Grillo; originator of V-Day and the M5S party.  Getty Images.

Tuesday, May 29, 2018

Rev 2 is Mostly Ready

Revision 2 of the cylinder for my Duclos flame eater engine, to replace the one I destroyed Friday, will most likely be ready to put back on the mill tomorrow.  I expected to get this one in a small fraction of the time spent on the first, since most of the time spent on the first one came from trying to figure out how to do certain things with tools I have (instead of immediately buying more new tools) and it did.  I spent about a week of "4 hour days" working on the first one, and about three of them on the second. 

It's not quite done.  The narrow diameter on the right needs to be reduced a little to press fit the pedestal onto this, and it needs to be cut off the extra rough stock that you can see in the lathe chuck on the left (wrapped in thin cardboard).  The same tool that made the fins on the cylinder will be used for that.  Most likely.

The truly detail-obsessed* among you will notice this one is different from the other, which is to say I also learned from my mistakes.  If you count, you'll see this one has nine fins; the other had seven and a smidgen of an eighth.  The print I'm building-to shows the slots and fins both being 3/32 wide (.0938").  On the first one, I just advanced the cutting tool by twice that and expected it to turn out.  I ended up with tolerance buildup - most of the fins and spaces ended up 7/64 wide.  This time, I had the idea to use the blue layout fluid (you can see a little remnant of it in the pic) and layout where edges should be.  Then I marked the edge of a space (between fins) by cutting a couple of thousandths deep; it allowed me to measure how wide the fin would end up and I could move the edge to make sure the fin was really .094 wide.

There are other small differences that I won't get into.  Think of it as a challenge.

I expect to spend more time agonizing over the setup with a dial indicator, verifying that it's the same height everywhere, and maybe putting a foot long pipe on the vise handle to clamp it tighter.  Basically, all the little tricks I've come across will get used, unless they contradict each other or something else.

( * "detail-obsessed" sounds better than "anal-retentive" doesn't it?)

Sunday, May 27, 2018

Memorial Day 2018

I know that for a lot of the country, Memorial Day is the unofficial start of summer and there will be cookouts and parties at the lake or beach or park.  Allow me join the chorus of folks saying that while you're enjoying your day, be it beach, barbecue, pool or whatever, take a moment to remember and thank those who have given their all in service to us.  Some don't get the chance to have that cookout, or be with their loved ones. 

There's a couple of pictures that I regularly run for Memorial Day, and this year I'm going to go with the image from 2011 that touches me by having an element of the unexpected. The images of women who have lost their husbands are gut-wrenching, but a dog isn't generally expected to have feelings this deep.  I went looking for the a photo credit and I found one this time.

In a final act of loyalty, Hawkeye, the dog of slain Navy SEAL U.S. Navy Petty Officer 1st Class Jon T. Tumilson walked up to his fallen master’s casket during the funeral in Rockford, Iowa, and then laid mournfully down beside the body for the rest of the proceedings  [Note: Petty Officer Tumilson was one of the 30 killed in Afghanistan in the shoot down of Extortion 17 which the families blamed squarely on the Obama administration - SiG]
Far too large a portion of the ruling class could use Hawkeye's loyalty.  There are signs that's improving, no matter if it's temporary or not.  The others could ponder showing less humanity than a dog.  

No barbecues for us.  We're still under the clouds associated with that Tropical Storm over in the Gulf. 

And ... It's Ruined

The cylinder of my flame eater engine, that is.

The last thing I mentioned in that post was planning to make a set of thinner, taller jaws for the vise because the existing set was grabbing it below the centerline by a little over a quarter inch.  That creates a force to push it vertically out of the vise - or cuts a notch into the fins.  The SHCS that came in the vise were too tall to use on anything much thinner than the factory jaws, so I found some low profile button cap screws to order.  I figured I could thin the jaws by about an eighth inch on both sides, giving me a quarter inch more opening.  Oh, yeah, I ended up leaving the soft jaws 1-1/2" tall. I might lower that a little.   While waiting for the screws to arrive, I made the jaws out of some quarter inch thick plate I had.  They fit perfectly.

So now it was time for a test fit.

Seemed like it was all good. The gap between the bottom of the cylinder and the vise jaw figured to be 1" and I had a left over block of 1" bar stock.  (Look on the left between the closest jaw and the cylinder).  It felt very secure. It took me a while to figure out how deep to cut the fins and the 1-1/2" diameter part of the cylinder over on the right end because it's never really specified on the print. The print does show that the flat should be 1" wide, so a little geometry (and an online calculator) showed me I ought to cut it  0.190 - about 3/16" deep.  (Seriously - how deep do you cut that?  I think this is similar to what's called Geometric Dimensioning and Tolerancing, or GD&T. )

A friend convinced me to put an extra clamp across the top - I guess he was afraid of aluminum jaws replacing 3/8" steel - so I added that. I cut the flat over the base of the cylinder in a few cuts, .025 deep at at time (3/8 end mill) and it went very well. Which led me to decide to take off the 3/32 wide fins in a couple of passes. First pass at 0.100 depth followed by a second pass at 0.190. When I was done cutting off all the fins I thought I'd move the end mill toward the base as a spring cut (a second cut with the same settings; it removes some metal that gets compressed by the cutting forces in the original cut and "springs back" to a higher level), just to level out any cutting marks. Instead it dug in and ripped the cylinder open. Look at the shelf on the end where I stopped the cut. That's a deep cut at the far end. 

You can see how bad it is. The Z axis on the mill never went below -0.190", so as I moved right to left along the cylinder cutting the fins off, the cylinder must have pivoted and lifted the left end. I sure couldn't see it happen. You can measure the diameter to the flat by putting the calipers on the fin and the flat at both ends. The end closest to the camera is 1/16" smaller than the end by the pedestal. The flat spot on the right end of cylinder after the fins was supposed to measure 1.000 and measures exactly that. Like I say, the entire piece was cut with the EM never going deeper than -.190".

In the aftermath of trying to figure out what went wrong, I focused on the idea that the cutter was getting lower as I made the cuts, which were right to left in the pictures here.  To cut off the fins (3/32 or .094 wide) I raised the Z-axis of the mill from -.190 to -.100, moved to the next fin, made a cut, lowered the cutter back to -.190 and took another pass.  As a diagnostic, I set an indicator on the spindle, raised and lowered the cutter back and forth between -0.100 and -0.200 about 40 times.  The indicator never showed a change in position, which means the cutter wasn't getting lower every time I raised and lowered the mill's headstock. 

My guess is that the cylinder pivoted because even with the taller jaws and the 1" bar stock spacer, the contact area holding it is still pretty small.  Theoretically, the contact is only a line with one point on each fin; practically, the metal will spread out a little, but it's still a tiny contact area.  Since the cut is deeper on the left, that means it was rising into the cutter, pivoting around the right end.  There wasn't enough holding force to keep the cylinder from rotating. Maybe I should have made really light cuts? Maybe something between the jaws and the cylinder to keep it from sliding, like very light sandpaper or cardboard?

This was Friday and I've begun work on the replacement cylinder.  I don't see any way I could fix this one.  Maybe with welding equipment and an expert's touch, neither of which I have, but I do have more pieces of 2-3/8" diameter bar stock cutoffs that I can make into the new cylinder. 

I'll be the first to admit that my main problem in doing machine shop work is that I Know Nothing.  Well, not quite nothing, but I'm totally self-taught and when you're self-taught there are always holes in your knowledge.  If anyone sees this and has ideas on how not to make this screwup again, let me know! 

Saturday, May 26, 2018

A Visitor to the Backyard

We had a visitor to the yard that we've never seen before. 

That thing it's standing beside is the outdoor half of a mini-split air conditioner in the workshop.  Mrs. Graybeard was out looking at setting up to do some cleaning and noticed him.  There was another on a neighbor's wooden fence not 6' from us. 

Neither of us knows a hoot about owls, but this appears to be an Eastern Screech Owl.  Everything about habits and habitat seems to match up.  This is a corner of the lot where three neighbor's trees overlapping turn it into a fairly dense wooded spot.  The fact that they're supposed to be nocturnal and daytime sleepers explains the tired-looking eyes. 

Friday, May 25, 2018

Sometimes the Jokes Just Write Themselves

Machine Design's daily email brings news that Dyson, the company famous for its vacuum cleaners, is going after the electric vehicle market.  They're doing it by way a new technology, which they may be the first to bring to market: solid electrolyte batteries.
This past February, James Dyson made the decision to build more than just high-precision vacuums and fans and instead focus on electric vehicles (EVs). Dyson plans to construct three EVs by 2020, the Financial Times reported, [paywall] with an estimated $2.8 billion project. Much like Elon Musk, Dyson looks to shake up the EV market by using solid-state batteries instead of the lithium-ion versions.

According to the Financial Times, the trio of cars would be non-sports car high-end models which would scale in production aimed toward the mass market. The vehicles will be constructed out of light materials just like the BMW i3 EV carbon fiber body. The key is the solid-state battery which, theoretically speaking, will be able to hold more of a charge compared to lithium-ion batteries.
Solid electrolytes?  The electrolyte in a battery has one main function: to conduct the electron flow from one plate to the other.  In a lead-acid car starting battery, for example, the electrolyte is a conductive solution of sulfuric acid in water.  In "dry cells", the electrolyte is in the form of a paste.  Liquids or pastes work better than any solid currently known.

Although they never directly say what the cathode and anode (negative and positive plates) are in the battery, they claim a solid electrolyte battery will be smaller and higher energy density than existing batteries, as well as being safer and longer lasting.

It might be the reason they don't describe details of the battery is because they don't exist, yet.  At least not outside the lab, in industrial quantities. 
Currently, finding the right material for solid-state batteries is key. According to Axios, Samsung and Dyson have collectively invested $65 million in Massachusetts-based Ionic Materials. The firm claim to be making progress into the technology. Its new material, a liquid crystal polymer, may be able to solve many of the current issues of mass production.

Ionic Materials claims that lithium ions move as fast or even faster through their polymer than they would through a conventional liquid electrolyte system. This helps demonstrate the stability of the company’s polymer material. Second, the polymer works at five volts and can be made simply and cheaply. Third, while most materials in solid-state research operate at about 60°C (140°F), the firm’s material works at room temperature.
Axios points out that the right material to use for a solid electrolyte battery is lithium metal.  Pure lithium metal is highly energetic, and would add something like 30% more capacity to today's state-of-the-art electric car batteries.  Lithium just also has the unpleasant characteristic of exploding or catching fire if it comes in contact with moisture.   Ionic Materials claims they've developed a liquid crystal polymer that conducts electrons as well as a liquid but doesn't make the lithium do nasty things.    
The article opens by suggesting Dyson looks to shake up the electric vehicle industry by using solid-state batteries in its 2020 car lineup. Since the batteries don't exist and we're half past 2018, I'll say no, they won't.  2021?  Maybe.

Dyson's EV, the car from the company that makes things that suck.  The Vroom-ba? 

Thursday, May 24, 2018

Dolph Lundgren is More Qualified to be "The Science Guy" Than Bill Nye

Ran across this the other day.

They're all entertainers, it's just that Dolph Lundgren is more qualified to be "The Science Guy" than Bill Nye is.  And punk rock singer/rhythm guitarist Dexter Holland is a good contender, too.

Who'd you rather have: the MIT Fulbright Scholar, the Doctoral student in Viral Oncology and Proteomics, or "Bill Nye - the arrest everyone who disagrees with me guy"?   

Wednesday, May 23, 2018

Turning the Hardest Known Abrasive Into a Dry Lubricant

Diamond.  The world's hardest commonly available mineral (yes there are harder oddities that have never been synthesized in industrial quantities, as diamond has) and a favorite abrasive for as long as they've been known.  Diamond coated tools are widely used in industry, and I personally think the whole "granite kitchen counter" movement couldn't have happened without widely available diamond tools.

So when I think about diamond, I think about uses as an abrasive; perhaps a coating on a machine tool.  I'd never think of it as lubricant, but according to Machine Design some researchers at Argonne National Laboratory have found just that.  When they mixed molybdenum disulfide, commonly used as a lubricant in high temperature applications, with tiny diamond particles they call nanodiamonds, the diamonds turned into a form of carbon that creates a nearly frictionless lubricant that essentially doesn't wear out. 
The most commonly used solid lubricants on the market today take the form of graphite paste. They are used as lubricants to grease doorknobs and bike chains, among other things.

In 2015, one of the researchers, Anirudha Sumant, made a breakthrough in solid-lubrication technology by demonstrating superlubricity (near-zero friction) at engineering scale for the first time by using graphene combined with nanodiamonds. This approach was revolutionary, and since then his group has continued to further develop the technology.
Graphene, of course, is one of today's "wonder materials" that's being researched for just about everything.   Its structure is essentially the same as graphite's, in that it's two dimensional hexagons of carbon atoms in sheets looking much like atomic-scale chicken wire.  Unlike graphite, it forms large, continuous sheets a single carbon atom in thickness but of macroscopic sizes. 
Most recently, Sumant replaced graphene in the process with molybdenum disulfide to see how other materials would behave. He was expecting the process to resemble the one observed with graphene-nanodiamond lubricant. However, the team was surprised when they couldn’t see nanodiamonds in the material. Instead, they found balls of onion-like carbon.

The molybdenum disulfide was breaking up into molybdenum and sulfur and reacting with the nanodiamonds to convert them into onion-like carbon. Onion-like carbon consists of several layers of spherical graphitic shells that can be used as a dry lubricant. And the process of combining molybdenum disulfide and nanodiamonds automatically creates this form of carbon without any additional chemical application. The lubricant is also self-generating and readjusts itself continuously, so it lasts longer.

These carbon balls sustain high contact pressure and, due to their unique nanostructure, glide easily, creating superlubricity. The team concluded that the sulfur diffusion increased the strain in the nanodiamonds, subsequently breaking them and converting them into onion-like carbon.
The term "onion-like carbon" is one I've never heard; I imagine something like shells of something like graphite arranged similar to the layers of an onion.  They estimate the friction of this combination to be 1/10 of fluropolymers (I assume they mean Teflon and similar), which means moving parts will perhaps last 10 times longer before wearing out.   They also point out that there won’t be any hazardous liquid residue or the need to use and dispose of rags as part of the clean-up process (no word on its toxicity to parrots).  Machine Design speculates it could also be used to make parts that can’t be made today, especially with metal stamping.

“The amount is so small — a few drops for kilometers of sliding — that cost is not an issue,” Sumant said.
I suppose it's the counterintuitive result that adding a fine abrasive to an ingredient used in grease creates a better lubricant rather than grinding paste that appeals to me about this story.  Argonne National Laboratory already has three patents on the superlubricity technology, with a patent pending on this breakthrough, and will soon be licensing the technology. 

The formation of the "onion-like carbon"; the left picture shows the nanodiamonds (brown) lying on the molybdenum disfulide sheet, then being wrapped up in the MoS2, and eventually turning into the "OLC" on the right.  Full story in their paper in Nature

Tuesday, May 22, 2018

Publix Ruins Graduate's Proudest Moment






Monday, May 21, 2018

NASA/JPL Planning Autonomous Helicopter Drone for Mars 2020





NASA/JPL illustration.

This is Post #2800 In This Blog's Life

Just for fun, one from the emails.

Sunday, May 20, 2018

The Move to Make the Electoral College Irrelevant




Saturday, May 19, 2018

A Partially Done Part





Friday, May 18, 2018

Nuns Putting Pressure on Publicly Held Gun Companies













(Sister Judy Byron - Seattle Times photo)

Thursday, May 17, 2018

It's Kind of Sad




At the very top of the web site, it says:


Here's wishing them luck in whatever direction they choose.

Wednesday, May 16, 2018

Hacking Alexa, Siri and Google Assistant With Hidden Voice Commands






These security researchers aren't leaving bad enough alone. 





For some reason, it reminds me of this meme:

Tuesday, May 15, 2018

Inside the Worst Maritime Disaster in Decades






Monday, May 14, 2018







Sunday, May 13, 2018

Mother's Day 2018






Saturday, May 12, 2018

Redesigning the CNC Mill Enclosure





Friday, May 11, 2018















Will it hold up?  Time will tell.