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Yuan LIU
Works at Silver Spring Networks
Attended Chinese Academy of Sciences
Lives in Mountain View
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Yuan LIU

➥ What do you make? ►  - 
 
 
The first one (yellow) had the rear valve's diaphragm off base.  Additionally, the O-ring on the bi-directional valve had lost grease sealing.  The second one (blue) had the front valve pulled off and its O-ring jammed between its stopper and the shaft.  Some Vaseline and 30 minutes after, both pumps are back in working order.  Net profit?  $8 in replacement value.  In manufacturing value, perhaps $2, minus materials cost.

Really?  I most probably did not make minimum wage.

A college roommate of mine was a graduate student in Columbia University many years ago when he saw some dull drill bits in the lab and took care to sharpen them. He was very proud of tooling skills that he picked up after high school when Chairman Mao shut down China's universities and ordered the youth to "be reeducated by workers and peasants."  When he was busy showing off his accomplishment in the lab, his professor walked up and offered this: "I didn't pay you to sharpen drills."

Well, I don't have the pride of hand skills - of which I have none.  And even though the owner of these pumps, www.ClimateChangeEducation.org, couldn't claim that they didn't pay me to repair pumps - nor could they claim that they paid me to, for this is all on volunteer time, I am sure that Jim would rather my time be spent on actually improving the educational infrared hacks that his collaboration with my +Hackerlings have produced.  The pumps were used in public exhibitions where we showcased our collaboration.  The yellow pump had been lousy from the beginning.  In the most recent show, the blue one also faltered.

To Jim, replacing these pumps is too low a cost.  But to me, this is one opportunity to learn something about mechanics and product design.  If I hadn't opened these pumps, I wouldn't have known that, simple as they are, there are different mechanisms to construct - and techniques to produce them.  This reminds me of Mark Frauenfelder's first handmade wooden spoon described in his Made by Hand: Searching for Meaning in a Throwaway World.  All these simple builds add up to one's skills.  That is where I find value in my time.

And hoarding skills is not purely a selfish endeavour.  If, for example, the next time a pump - even a replacement unit, failed during a live show, I can fix it on the spot in two minutes.  How much would that be worth?
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Thanks, +Paul Frederick!  Silicone makes sense.
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Just this morning, I got amusement from yesterday's print about Univision headquarter directing its employees not to enter Trump properties on work time, and  Trump banning Univision employees from Trump premises. ("It is not clear," the article mused.  "How Trump staff is going to prevent Univision employees from entering if they are not in uniforms.")  Is there an NBC building next to a Trump property?
NEW YORK (AP) — NBC said Monday that it is ending its business relationship with mogul and GOP presidential candidate Donald Trump because of comments he made about Mexican immigrants during the announcement of his campaign.…
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Once in a while, Google Awesome is awesome 
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❖ STEM Education  - 
 
 
Science education in public fairs: Your visitors give you 5 minutes of their attention.  Do not give them yet another feel-good experience.
This was a hard one for one simple reason: Every lab setup failed at one time or at all times.  But as long as one part of the lab is functional, we… - Yuan LIU - Google+
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Science education in public fairs: Your visitors give you 5 minutes of their attention.  Do not give them yet another feel-good experience.
This was a hard one for one simple reason: Every lab setup failed at one time or at all times.  But as long as one part of the lab is functional, we… - Yuan LIU - Google+
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In-Depth Discussion  - 
 
Public exhibitions allow only short interactions.  How to avoid yet another feel-good booth?  Jim of www.ClimateChangeEducation.org and I are determined to instill stringent scientific thinking despite time limitations.  After two public fairs, I switched from story centric instructions to challenge style interactions.

After an introduction of premises and setup, the audience is asked to form and test their own hypotheses, like a practicing scientist. (OK, more like a science fair contributor.)  Challenges are loosely sequenced so their likely hypotheses will be alternately true and false. (Examples in the posting below.)  Success in the true hypothesis will boost confidence in forming the false one.  Nothing stimulates deeper thinking than using one's hands to disprove ones own hypothesis.

By challenging children to form and test their own hypotheses, I can easily command their attention for five minutes and longer as compared to two minutes when they are shoved into my my booth by their parents.  In fact, this formula helps adult visitors as well, especially parents eager for their children to succeed.  I often see children more amused than bemused while their parents (who secretly follow the same reasoning) the other way around.

I discovered this true-false shock at AAAS'  #FamSciDays  (https://plus.google.com/b/109723977854343280863/events/cjtsvk7glm2phdcipvf8s7d2840) when I used a magnifying glass as a follow-through of Jim's lesson about far infrared at a FLIR camera.  Surprise factors are not uncommon among public science showcases aimed at children.  What drew me to join forces with Jim was his determination to not stop at opening children's eyes, but to give them a scene, namely a deeper view of the science behind the eye-opener.  Shortly after our first joint exhibition at Bay Area Science Festival (https://plus.google.com/b/109723977854343280863/events/c38nqvk4rldcubg74sqdhs93k1o), I joined a school STEAM show to celebrate Isaac Newton. Determined to bring Jim's vision into school fair, I dug out the Newton-Hyugens debate and designed a multi-step mini lab that a kid can complete in 5 minutes to illustrate deduction, inference, what have they by the two giants.  The purpose is to reveal fallacies in interpreting empirical evidence (and falsification as the driver of science evolution).  The observation that elementary schoolers are eager to argue with Newton is very exciting.

After the AAAS show, I had one week to another school STEAM fair as a special guest. (https://plus.google.com/+YuanLiuTheDoc/posts/655egFpRqch)  I decided to combine the true-false shock with fallacy exposé.  So I wrote up science fair panels on IR absorption, starting with a false hypothesis that readily agreed with the lab's Step One.  Here came my first visitor with his well educated father.  The father, oblivious of all my project panels, guided his son straight into my trap du jour!  There, I invited them to read the panels and steered the pair through the rest of the lab.  When they were confronted with conflicting results from controls, I gained the golden opportunity to teach Scientific Method 101.

A week before Green Kids, I need to prepare for a water-themed STEAM night. (https://plus.google.com/+YuanLiuTheDoc/posts/ZNSoYmCAJJs, where I also ignited hydrogen.)  I built another challenge into my water sensor hack.  Whereas smart irrigation demo got kids attention, falsification of "water is conductive" really got them thinking.

The formula was well received at each of these events.  No wonder one of Green Kids visitors declared ours "the most interesting demo I saw that day" despite obvious equipment failures on our table. (I'll gradually post some of these scripts.)

Your visitors give you five minutes of their attention.  Do not give them another feel-good experience.
 
This was a hard one for one simple reason: Every lab setup failed at one time or at all times.  But as long as one part of the lab is functional, we deliver compelling lessons.

How, would you predict, these LEDs will (or will not) change, and this dial will (or will not) move, if I insert this piece of paper in between this and this?  What about this magnifying glass?  Now, you prove it by doing exactly that!  Surprised?  What is your theory, now that you have known so much about infrared?

Of course, we went there not for paper and magnifying glass.  How would these instruments change (or not change) if I pour this bottle of air into the gap?  What about that bottle that looks no different?  Now, hold the bottle and prove your prediction!  Dropped jaw?  Dilated iris?  Good.  That's what we call a teachable moment.

Where in public education when you, the audience, prove to the world with your own hands that an invisible greenhouse gas does what greenhouse gases do, trapping energy from invisible infrared while letting visible light pass?  Only in presence of www.ClimateChangeEducation.org and Mountain View Hackerlings, the two Educational Incredibles™ who battle the two conspiring Invisibles™.
(Free) Hackerlings in Mobile Climate Labs at Green Kids Conference (2 photos)
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If you are considering a combined unit of 3D printer, a 3D scanner, a laser engraver, a CNC engraver - or some combination thereof, this can be a strong contender at extremely affordable price.  I particularly like that they don't require you to use proprietary consumables, which several price-leaders in the domain (including XYZPrinting) do.
 
We have pledged full perks.  Something to consider for your own: Metal frame, generic consumables.  Printer, scanner, laser engraver and CNC engraver together for ~US$100 less than XYZPrinting's market leading price on entry-level scanner-printer combo.  If you only need printer, US$400; or for feature-parity with XYZ, US$450, roughly $200 less. (Thanks, +ciprian moloci, for sharing!)
3D printing, 3D scanning, CNC/laser engraving, and even more extensions | Crowdfunding is a democratic way to support the fundraising needs of your community. Make a contribution today!
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The first one (yellow) had the rear valve's diaphragm off base.  Additionally, the O-ring on the bi-directional valve had lost grease sealing.  The second one (blue) had the front valve pulled off and its O-ring jammed between its stopper and the shaft.  Some Vaseline and 30 minutes after, both pumps are back in working order.  Net profit?  $8 in replacement value.  In manufacturing value, perhaps $2, minus materials cost.

Really?  I most probably did not make minimum wage.

A college roommate of mine was a graduate student in Columbia University many years ago when he saw some dull drill bits in the lab and took care to sharpen them. He was very proud of tooling skills that he picked up after high school when Chairman Mao shut down China's universities and ordered the youth to "be reeducated by workers and peasants."  When he was busy showing off his accomplishment in the lab, his professor walked up and offered this: "I didn't pay you to sharpen drills."

Well, I don't have the pride of hand skills - of which I have none.  And even though the owner of these pumps, www.ClimateChangeEducation.org, couldn't claim that they didn't pay me to repair pumps - nor could they claim that they paid me to, for this is all on volunteer time, I am sure that Jim would rather my time be spent on actually improving the educational infrared hacks that his collaboration with my +Hackerlings have produced.  The pumps were used in public exhibitions where we showcased our collaboration.  The yellow pump had been lousy from the beginning.  In the most recent show, the blue one also faltered.

To Jim, replacing these pumps is too low a cost.  But to me, this is one opportunity to learn something about mechanics and product design.  If I hadn't opened these pumps, I wouldn't have known that, simple as they are, there are different mechanisms to construct - and techniques to produce them.  This reminds me of Mark Frauenfelder's first handmade wooden spoon described in his Made by Hand: Searching for Meaning in a Throwaway World.  All these simple builds add up to one's skills.  That is where I find value in my time.

And hoarding skills is not purely a selfish endeavour.  If, for example, the next time a pump - even a replacement unit, failed during a live show, I can fix it on the spot in two minutes.  How much would that be worth?
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+Yuan LIU​​ that's a great story behind why you decided to fix the pumps. You're correct, the next time one fails you'll be able to fix it on the spot. :) 
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Thank you, +rare avis 
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Science News (Pop Sci)  - 
 
 
Public education in public fairs: Your visitors give you 5 minutes of their attention.  Do not give them yet another feel-good experience.
This was a hard one for one simple reason: Every lab setup failed at one time or at all times.  But as long as one part of the lab is functional, we… - Yuan LIU - Google+
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#water#balloon#gif#gifs#balloon popping#slowmotion#slow motion#slow motion gif
#water   #Ballon   #gif   #ballon  popping #slowmotion  gif
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Yuan LIU

➥ Arduino  - 
 
Somewhat Arduino-related, but the remaining question is broader: Can MOSFET exhibit "soft" breakdown?  Or is there another cause of the temporary failures?  The consensus in the original discussion is ESD, not water.  In my mind, water could only fail button but button did not fail (besides the fact that the board was 12cm above the table), while ESD should be irreversible but the set recovered.  So neither theory is very satisfactory.  I have retested the set at random times in the past few days since the last "recovery".  It hasn't failed. (In contrast, it could alternate between failure and recovery within minutes on the first two days after initial "damage".)
 
My Pro Micro has a strange condition that suggests a soft breakdown.  The pull-up resistor on Pin 16 (which I use for the calibration button) seems to have "lost strength," in that instead of pulling the pin to 5V, the voltage is only 0.4V.  However, if I set its mode to OUTPUT then write HIGH, I get 5V.  After that, the pull-up function will work for some time.  I cannot predict how long it will last, so I ended up with a setup that includes an OUTPUT write before INPUT:

void setup() {
...
  pinMode(buttonPin, OUTPUT);
  digitalWrite(buttonPin, HIGH);
  pinMode(buttonPin, INPUT_PULLUP); // activate pullup resistor
}

Even with this, there are still times that writing HIGH to INPUT mode (which is what INPUT_PULLUP mode does) only raises the pin 0.4V.  Without setting up external pull-up, I know of a workaround: Perform digitalRead() in OUTPUT mode.  But as my button is directly connected to GND, it would draw unreasonable current - even if for a short time.

Does anyone know about this input soft breakdown?  I had used this bargraph in two public shows with no trouble.  In the third show last weekend (https://plus.google.com/events/c5tr84ve1a7snj27lrba5v7q9oo), I accidentally spilled water on the table.  The entire day, the board worked intermittently for only a few minutes.  Though I did not believe that water got onto the board, I still suspected that the button got short.  But eventually, I verified directly that the button was working correctly. (At the same time I discovered the input breakdown on Pin 16, I tested INPUT_PULLUP on a spare pin, and it was 5V.  But then Pin 16 recovers and breaks down at random times, so it is hard to say if the other pin would always remain good.)

In case you haven't seen my previous posts, this bar graph is built for AAAS Family Science Days (https://plus.google.com/events/cocnp0vgr3ljmchnt2tavimqego) as part of www.ClimateChangeEducation.org and +Hackerlings' effort to bring infrared gas metrology labs to public education.

After setting up the workaround, I made one more improvement: Suppress all 9 low LEDs and light only the 10th to indicate calibration mode. (As was shown in the last video in album, the calibration button used to suppress the first low LED but let any lit LED lit - LED 10 would never be lit or calibration wouldn't be needed.  Whereas that saved some code, the indication was subtle and would lose indication when the button pin malfunctions.)  The new video shows a complete demonstration of gaseous greenhouse effect in two minutes.
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+Yuan LIU
Something cooked the chip. At least with a buffer you could just replace it.
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Yuan's Collections
People
In his circles
399 people
Have him in circles
602 people
Susan M Davis's profile photo
Julia Ann Souders's profile photo
Marcley Santos's profile photo
Rohmani Endang's profile photo
SugarPot Pie's profile photo
Jake Croston's profile photo
Justin Broughton's profile photo
Trina G-Liu's profile photo
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Currently
Mountain View
Previously
Montreal - Beijing - Chengdu
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Work
Employment
  • Silver Spring Networks
    2010 - present
  • Chinese Information and Networking Association (CINA)
  • Electronic Data Systems
    2002 - 2010
  • Nuasis Corp
    2000 - 2002
  • ChiTech
  • Sunrise Chinese Library (太阳升)
  • China News Digest (CND)/华夏文摘
  • Memorial University of Newfoundland
  • McGill University
  • Concordia University
  • Université de Sherbrooke
  • Institute of Acoustics
Education
  • Chinese Academy of Sciences
    Acoustics
    Ph.D., M.Sc.
  • Sichuan University
    Physics
    B.Sc.
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