Sunday, August 30, 2015

Minnesota State Fair

Lots and lots of people!  Yesterday's attendance was 180,000 people and today's will probably push into 200,000 or more folks of all kinds stopping in to see the livestock, amusement rides and the state of Minnesota's biggest sugar beet and of course the blue ribbon ear of corn...

So here are just a few iPhone pics, I hope you enjoy.  The most remarkable thing I saw at this fair was a gigantic boar named Captain Jack... and ate a really good gyro for lunch!

The main gate was busy and efficient!

This is a pic of a low traffic street!

The famous SPAM kiosk - something of a Minnesota acquired taste.

A beautiful Percheron getting a washing, the man grooming the horse is about 6 feet tall... these are some very big and beautiful horses!

I have never seen Vaulting before... in front of this horse there is a team of girls that performed a sort of gymnastics on horseback. 

These gals were amazing! They moved with the cadence of the horses.
Some very curious lamb

This is "Captain Jack," he's a 5 year old boar and weighs in at 1080 lbs! To get an accurate perspective, this animal is around seven feet long with a snout the size of a bucket. Notice the grain dish in the back ground...

Some beautiful plants in the Horticulture Building

An award winning flower arrangement...

Some Blue Ribbon corn... gosh there was LOTS of corn. How you can tell the best from the rest?

Another really nice weekend!


Monday, August 24, 2015

The Glensheen Mansion

During the early 1900's an incredible amount of wealth was amassed by a small number of people who were smart enough to make the right investments, business decisions and saw some kind of future.  Many would get one or all of those things wrong and lose everything... a few would be lucky enough to grow even bigger and become the sustaining wealthy for generations.  Such was the case for the self taught teacher turned lawyer - Chester Adgate Congdon. 

With chance circumstances, intellect and opportunity Chester  made a fortune in mining.  This is one of the homes he built on the shore of Lake Superior in 1905...

This is Glensheen
An amazing place with a gold leaf ceiling, the finest wood carvings and a fantastic view of Lake Superior.  Located between two creeks... which make it a a glen... the mansion took three years to build and nearly a million dollars in 1905.

This is the "barn" a stable for the estates horses and cattle.  Just South of this structure are beautiful gardens which were maintained by the estates resident gardener.
This beautiful garden is to the North of the house and sits between the estate and Lake Superior.
There is a gardener's guild that tends to these gardens.


There was at one time six miles of hiking trails on the estate. This bridge crosses one of the creeks that cross the property.
There is a sad footnote to the Congdon mansion story.  In 1977 a psychopathic grand daughter and her husband murdered the last surviving daughter of Chester Congdon to try to get an inheritance.  The story is told in this very insightful book.

Holy cow! 


Sunday, August 23, 2015

Lots of smoke in the air

I recently spent some time in California and took this pic a few days ago. 

The low pressure weather system made for some transport of smoke from the forest fires that are still a problem in the Northwestern US. 
Let's hope we get some rain out there soon!


Monday, August 17, 2015

Sculpture err, art on the side of the road...

Every now and then I drive past something really unusual... like the school bus / deer blind a farmer put on top of an old steel tank for himself and 20 of his friends - set prominently in a corn field... the robot driving a tractor in Tennessee and these fine examples... As art is supposed to do, these inspire ideas, conversation and emotion.  So what do you see?

Boom boxes on a stick...

Grass somehow growing from a leg shaped thingy planted into / upon steel shoes, so you just have to pose for a pic like this... Humor is what I see in this one.

Sort of, Vikings meet space alien -  Mork?

A suspended shack - I suppose we could swing this, find the periodicity and calculate the moment of inertia, but I doubt the artist was going for that...

This rotates with the wind! I see tiny alien amusement park ride...
Hope you liked the pics...


Sunday, August 16, 2015

Another visit to one of our favorite places...

Yesterday was a very special day, at the confluence of two beautiful rivers.

Life is good.

Saturday, August 15, 2015

The night sky

I've been cleaning the optics on my old catadioptric and that's almost ready to get back into service.  New T-ring adapter for the Nikon... so a think a lunar post or maybe the rings of Jupiter will make there way into this blog soon.  Just need another good clear night and some anti-bug stuff.

So last night it was a clear sky, and I took these two pics with the camera stopped down to F3.5 and an ISO of 100.  Just a little experiment with long exposures.

I actually saw a couple of the Perseid meteorites this evening. But wasn't set up in the right place to capture those.

A proper 30 minute long exposure focused on Polaris. 
Dubhe and Merak were very bright in last nights low haze atmosphere.  Not as good as a winter pic, but still fun! Did you know that the pole star has changed over time?  If you look carefully at the 30 minute exposure there is very little tracking around several faint stars clustered around Polaris.


Tuesday, August 11, 2015

Driverless Car Town opens it's doors in Michigan

You've heard about Google Car, here's a controlled University studied test track for the driver less car.

I recently read an economic analysis on the automated car  -  its impact is huge.  Lots of challenges to be sure, but a tremendous reduction in manufacturing and a net improvement in utilization.

This analysis is really fascinating...

And the idea of an energy brokerage... Here's an energy hotel being developed at Aachen. Storing - or "hoteling" - power in a standardized way to be bought and sold...  This idea has been around for a long time, the exciting thing is... it's now happening.  The economics are now favorable...  Maybe the ABET folks will finally revisit the old Electo-Chemical Engineering degree debate!

The confluence of these technologies are making some pretty exciting changes in our world!


Sunday, August 9, 2015

Timm's Hill trek

How many people can say the have been to the highest point in the State of Wisconsin?  Well today I can claim membership in that elite club!

Timm's Hill is a geological bump in the beautiful Northwoods of Wisconsin, it's not very high... but it was fun to go there and to be able to say... yup, been there - done that - 48 to go!

Timm's Hill is the location for today's trek.  A very nice county park  is home to Wisconsin's highest point. Several hiking trails and a tower are there to get you above the trees to see the beautiful view.

There's a walking trail and a horse friendly trail a few hundred feet away.

Along the walk up the hill is this memorial.
The trail is well groomed.  You walk under a canopy of trees.

Atop the hill is this tower.  At the base of the tower there is a bench donated by the Highpointers... Today it was raining in the distance with the occasional thunder clap in the distance.
The pano view with a little spectral editing...

Highest natural point... 

We signed the visitor register...  They had engineering paper to write on!

On the way back down, another memorial tribute.
But let's not forget Michigan's highest point...  It's located near L'Anse in the beautiful Upper Peninsula and is called Mt. Arvon! 

Well there you have it... that's pretty much what you see at the Michigan site...

Looking around on the top of Michigan's highest natural point  is kind of like... "wooded."
Hope you liked the pics, check out the Highpointer's site...


Thursday, August 6, 2015

Internal Combustion Engine Torsional Harmonics - where do they come from? Part 1 - the combustion cycle.

Some of my most popular posts world-wide are the torsional discussions.  So, I thought for my 100th blog post I'd spend a little time writing about the nature of these twisty harmonics, where they come from and what they look like in rotating machinery...

  • The four stroke and how torque looks to the transmission of a vehicle.
When ignition takes place there is a sudden rise in pressure inside the combustion chamber.  This pressure is essentially what gets turned into motive force as the crank shaft inertia carries it over top dead center and the gasses are allowed to expand as they burn the fuel at some f/a mixture.  Most engines these days are 4-stroke thermodynamic cycles... Atkinson, Miller, Otto, Diesel, lots of thermodynamic nuances are associated with the various cycles but they have one thing in common so they all look similar (not exactly the same) but very similar to the torque that ends up at the flywheel.

So 4 strokes... just to catch up some of my non-technical readers, is the description given to the number of times the piston either rises or falls during a complete combustion cycle.  For example, in a common diesel engine and starting from an arbitrary top dead center position let us define these "strokes."
1st stroke if you will, the starter motor turns the flywheel which is attached to the crankshaft.  The inlet valve opens and in comes a fresh charge of air in our Diesel Cycle, gasoline and air in our Otto Cycle.  As the piston arrives at the bottom of it's first stroke, the inlet valve closes.  This turns the combustion chamber into a closed pressure vessel for the moment. This is called the Intake Stroke.

2nd stroke is the crankshafts turning now advancing the piston up from bottom dead center, with inlet and exhaust valves closed.  As the piston compresses the air in the diesel cycle, temperature rises.  Pv=nRT remember.  So as pressure climbs, so does temperature.  The same thing is happening in the Otto Cycle or gasoline (benzene engine) only the pressure rise is much lower.  Why? that's a discussion for another day.  Lets just acknowledge that the two different fuels ignite at different temperatures with different burn rates and energy release.  These different chemistries require the different pressures to yield useful power to the crankshaft.  Somewhere near top dead center of the second stroke, an injector atomizes diesel fuel into the combustion chamber - the temperature rise created by compression then ignites the fuel/air in the Diesel Cycle, or the spark plug ignites the gasoline engine's charge of fuel and air in the Otto Cycle.  So a few crankshaft degrees away from TDC the charge ignites.  The pressure increase in great and fast, and the flywheel inertia beats the burn rate induced pressure to get us back to TDC with rotational momentum.  This is called the Compression Stroke.

The 3rd strike then, is the piston traveling back down the cylinder bore.  The valves are closed and the pressure rises as the fuel is burned and the various chemical reactions take place.  As the piston nears Bottom Dead Center (BDC) the exhaust valve pops open... This is called the Power Stroke.

The final stroke is the piston travel up from BDC with exhaust valve open.  The piston pushes out the burned gases and as it nears TDC the exhaust valve closes, and the inlet valve starts to open... In actuality the valves open and close with durations that overlap.  This is useful for a lot of reasons, but again, fodder for another discussion on emissions and volumetric efficiency.

Now we return to the 1st stoke all over again... suck, squeeze, boom, blow...  that's how a 4 stroke cycle engine works.

Now think for a moment on what that sudden pressure rise looks like to the flywheel.  The entire process takes 4 strokes, which require two crankshaft revolutions to complete.  DING. Imagine two complete revolutions with one large asymmetric torque rise in the repeating cycle.  That describes in words why we have harmonics.  Now lets see a visual on that...

What does this look like then?

The top line is combustion pressures effect on the slider-crank mechanism - torque, the lines below show the descretized sine waves that summate to the original wave form.  So note, phase, frequency, and amplitude are a function of the conrod length, piston mass, crank length, boost, valve overlap and fuel charge rate and consequent fuel burn rate... The lines below the "torque curve" are referred to as "orders" - basically multiples of crankshaft speed for ease of use in building the resonant speed diagram for a system and later in understanding what order may be exciting a system mode dynamically.
Another post on what to do with this information and how it gets used in a forced response model is coming!  I'll eventually write up the numerical solution to the set of ODE's that drive the forced response simulation.  For me, this has always been one of the most enjoyable areas of engineering. There's crankshaft angles, coupling heat load capacity, and a lot of other details to ponder.  The intersection of the engineer's application of math to the solution of torsional vibration problems is one of those existential pleasures of engineering!

The development and solution of the equations are pretty straight forward, however there is a lot of detail in how you treat damping, various crank throw stiffness, inertia torque (which is opposed to gas torque) and other interesting phenomena.  Electric drives and gearboxes all have their own effects... as well as drive shafts, chains, tires, axles, propellers, impellers, ... they all make up the system and they all provide vibratory energy storage which means they all to a greater or lesser extent shape the modal response curve. The pic is from a book I wrote a Torsional Vibration chapter in many years ago. Identifying resonances and synthesizing drivetrains is a very interesting engineering activity.
Summer is flying by, so that's all for now,