RSS

Author Archives: admin

Fall 2018

Facebooktwittergoogle_pluspinterestmailby feather
 

Posted by on October 31, 2018 in Uncategorized

Leave a comment

Looking into the hyperloop.

This is a work in progress, so check back for updates!

I wanted to address the white paper produced by Elon Musk in 2013. It is an interesting concept, that several companies are actually perusing, but I am concerned with technical, economic, practical, and psychological implications of the system. As a concept, it has a strong appeal, aircraft speed on the land. From a technical perspective, in this engineer’s opinion, it poses technical challenges rivaling or exceeding landing on the moon. The economies outlined in the white paper are optimistic, at best, and I will attempt to compare the prices to real world transportation systems. The practical application of this technology appears to ignore an ever present issue in mass transit, the last mile problem. Finally, there are myriad psychological issues, including claustrophobia, uncomfortable acceleration and deceleration, and, most importantly, the American’s concept of freedom in transportation.

First, I would like to examine the technical issues. I will quote sections of the white paper in their entirety.

Earthquakes and Expansion Joints

A ground based high speed rail system is susceptible to Earthquakes and needs frequent expansion joints to deal with thermal expansion/contraction and subtle, large scale land movement.

By building a system on pylons, where the tube is not rigidly fixed at any point, you can dramatically mitigate Earthquake risk and avoid the need for expansion joints. Tucked away inside each pylon, you could place two adjustable lateral (XY) dampers and one vertical (Z) damper.

These would absorb the small length changes between pylons due to thermal changes, as well as long form subtle height changes. As land slowly settles to a new position over time, the damper neutral position can be adjusted accordingly. A telescoping tube, similar to the boxy ones used to access airplanes at airports would be needed at the end stations to address the cumulative length change of the tube.

These three short paragraphs are the first example of hand-waving that belittle the technical challenges ahead.  In the second paragraph, it is evident that Mr. Musk is not familiar with ‘Sun Kinks’ which are an issue that conventional railroads have to deal with.  The ‘Tucked away inside each pylon’ dampeners is what is know as track ballast in the railroading world.  All the rock they lay beneath railroads is not there for decorative reasons.  The tubes that would be used will not be pre-stressed and regardless, will undergo thermal expansion and contraction.

The third paragraph mentions accordion style sections of tube to take up changes in overall length.  Two major issues here:

1) The technology to create an expanding accordion structure that can withstand the pressure differential between the proposes internal near vacuum of the tube, at 100Pa and normal air pressure of 101.325kPa, or 14.7PSI, so the outside pressure is 1013 TIMES greater than the interior pressure, does not exist.  I don’t even know if it is even possible.

2) The sheer magnitude of thermal expansion is not represented here.  The distance between Los Angeles and San Francisco is 381.9 miles, following the I-5 corridor, which is the proposed route.  During a typical day, even in LA, a 25°F temperature change is a normal day.  So:

The calculation for thermal expansion is pretty easy: amount of thermal expansion = length of material * change in temperature * thermal expansion coefficient.  In this case, we will use steel, which is 0.0000065 (inch/inch/degree F).  Which seems like a small number, until you plug the numbers in:

Thermal expansion=381.9miles*5280feet*25°F*0.0000065*12=327.67 feet.  For those keeping track at home, this over 100 yards, a football field, with the end zones.  The accordion at each end would have be over 150 feet long to deal with a typical day’s temperature swing! Over the course of a year, you are looking at 2 to 3 TIMES that change.  As an example:

Another proposed route is between Kansas City and St Louis, MO.  250 miles.  So 250miles*5280feet*75°F(seasonal swing)*0.0000065=643.5 feet over the course of a year!  Just under an eighth of a mile, or a city block.

Even today, 200 years after the invention of railroads, engineers are still battling thermal expansion of steel rails.  The same steel that will be used in the proposed Hyperloop.  The next time your ride the rails, the click-clack you hear is one small thermal expansion joint after the next.

This problem alone is not insurmountable, but will require the design of a new type of vacuum proof expansion joint, which does not exist.  The proposed solution of a freestanding tube system will not work.  Tunneling would be more feasible, but very expensive.

The document now turns to the more technical section:

Reading into the white paper, I realize it will be impossible to separate the technical, economic, practical, and psychological issues with the system, since the original white paper mixes them as well, so from this point forward, I will address the issues in the order they were laid out.

This first major error that I foresee is capacity:

The Hyperloop is sized to allow expansion as the network becomes increasingly popular. The capacity would be 840 passengers per hour which more than sufficient to transport all of the 6 million passengers traveling between Los Angeles and San Francisco areas per year. In addition, this accounts for 70% of those travelers to use the Hyperloop during rush hour. The lower cost of traveling on Hyperloop is likely to result in increased demand, in which case the time between capsule departures could be significantly shortened.

These numbers didn’t seem all that realistic to me, so I went to see how many people actually travel between LA and San Francisco.  By air, it is 10,500,00, by car, 290,000 VEHICLES PER DAY, or 105,850,000 trips per year on I-5, with the caveat that the 290,000 per day is vehicles, with 1 to 6 people per vehicle.  Assuming 1.5 people per vehicle, you are looking at something like 150,000,000 people per year, for just cars + 10,500,000 by plane.  160,500,000 passengers per year/365/24=18,321 people PER HOUR, assuming 24/7, evenly spread out.  The Hyperloop could handle 4.5% of the average traffic.

The second issue is the acknowledgement of rush hour needs.  840 passengers an hour would be woefully inadequate. Just in Chicago, for just the O’hare stop for the Blue Line, there were just shy of 4,000,000 passengers.  For the O’hare stop, during rush hour, they average 2684 people an hour during the MORNING rush hour.

 

 

Facebooktwittergoogle_pluspinterestmailby feather
 

Posted by on October 30, 2018 in engineering

Leave a comment

VOTE

Please, everyone, be sure to vote in these midterms, they really matter.

Facebooktwittergoogle_pluspinterestmailby feather
 

Posted by on September 14, 2018 in Uncategorized

Leave a comment

Whiteness

Just a little experiment here, let’s take a look at the current cabinet:

22 positions.  1 African American, 1 Chinese American.  6 women.

90.9% White, 9.1% Non-White, 4.5% African American, 4.5% Chinese American, 27.2% Women. 0% Hispanic/Latino.

For the United States, the general demographics are:

62.0% White, 17.3% Hispanic or Latino, 12.6% Black/African America, 5.2% Asian.  50.5% women.

If you have any doubt about how the current administration views woman and minorities, the proof is here:

 

United States Secretary of State

Mike Pompeo official photo (cropped).jpg

Incumbent
Mike Pompeo

since April 26, 2018

United States Secretary of the Treasury

Steven Mnuchin official photo (cropped).jpg

Incumbent
Steven Mnuchin

since February 13, 2017

United States Secretary of Defense

James Mattis official photo (cropped).jpg

Incumbent
Jim Mattis

since 20 January 2017

United States Attorney General

Jeff Sessions, official portrait (cropped).jpg

Incumbent
Jeff Sessions

since February 9, 2017

United States Secretary of the Interior

Ryan Zinke official portrait (cropped).jpg

Incumbent
Ryan Zinke

since March 1, 2017

United States Secretary of Agriculture

Sonny Perdue headshot.jpg

Incumbent
Sonny Perdue

since April 25, 2017

United States Secretary of Commerce

Wilbur Ross headshot.jpg

Incumbent
Wilbur L. Ross

since February 28, 2017

United States Secretary of Labor

Alexander Acosta headshot.jpg

Incumbent
Alexander Acosta

since April 28, 2017

United States Secretary of Health and Human Services

Alex Azar official portrait (cropped).jpg

Incumbent
Alex Azar

since January 29, 2018

United States Secretary of Housing and Urban Development

Ben Carson headshot.jpg

Incumbent
Ben Carson

since March 2, 2017

United States Secretary of Transportation

Elaine Chao official portrait (cropped).jpg

Incumbent
Elaine Chao

since January 31, 2017

United States Secretary of Energy

Rick Perry official portrait (cropped).jpg

Incumbent
Rick Perry

since March 2, 2017

United States Secretary of Education

Betsy DeVos official portrait (cropped).jpg

Incumbent
Betsy DeVos

since February 7, 2017

United States Secretary of Veterans Affairs

Robert Wilkie official portrait (cropped).jpg

Incumbent
Robert Wilkie

since July 30, 2018

United States Secretary of Homeland Security

Kirstjen Nielsen official photo (cropped).jpg

Incumbent
Kirstjen Nielsen

since December 6, 2017

Office of the United States Trade Representative

Robert Lighthizer
Robert E. Lighthizer official portrait.jpg

Director of National Intelligence

Dan Coats official DNI portrait.jpg

Incumbent
Dan Coats

since March 16, 2017

United States Ambassador to the United Nations

Nikki Haley official photo (cropped).jpg

Incumbent
Nikki Haley

since January 27, 2017

Office of Management and Budget

Mick Mulvaney
Mick Mulvaney official photo.jpg

Director of the Central Intelligence Agency

Gina Haspel official CIA portrait (cropped).jpg

Incumbent
Gina Haspel

since May 21, 2018

Administrator of the Environmental Protection Agency

Andrew Wheeler official photo.jpg

Incumbent
Andrew R. Wheeler
Acting

since July 9, 2018

Administrator of the Small Business Administration

Linda McMahon official photo (cropped).jpg

Incumbent
Linda McMahon

since February 14, 2017

Facebooktwittergoogle_pluspinterestmailby feather
 

Posted by on August 11, 2018 in Political, Social

Leave a comment

20 Years

It is the year 2018.  Everyone in the developed world carries a supercomputer in their pockets now, with instant access to the sum of human knowledge.  How much has changed in the last twenty years?  This is a personal perspective of how much has changed.  I am not here to bemoan our current state of affairs, with a undying affinity to days long past, no, I am here to show how life was different for me and a good percentage of Americans 20 years ago.

First off, computers were developing rapidly at the time.  Most computing was done on desktop computers, Pentium MMX and K6 chips in the 200Mhz range were most common.  64mb of RAM was the standard at the time.  Windows 98 was released pretty late in the year, so most people are running Windows 95 or still clinging to Windows 3.1.  In August of 1998, Apple would release the iMac.  The computer that saved the company.  With a G3 processor running at 233Mhz, it could go toe to toe with any windows machine and was cute as well.  Many people were already online, via American Online, or other dial-up services.  33.6Kbps modems were the standard at the time.  Google didn’t exist yet.  Yahoo, Alta-Vista and Hotbot were the search engines at the time.  Only hard core enthusiasts had their own websites.  Cyberphreak.com started in June, 1998.  CRT monitors were the standard display technology.

Portable computers were popular, with the Palm III released and the first Palmtops from HP and Casio out as well.  The smartphones we use today owe a debt to Palm, the interface is virtually identical.  They were monochrome, but they worked and great ways to store contacts, calendars, and tasks.  Cell phones were gaining in popularity, but the plans were expensive.  Everyone still had a home phone and that phone line was usually used for connecting online.

In the living room DVD’s were released the year before and the uptake of DVD’s remains as the fastest media transition.  Everyone still has a VCR and it was the only way to record television.  If you wanted to watch a movie at home, you would have to take a trip to the local video store or Blockbuster.  You would watch these movies on a 21 to 32 inch CRT, in 4:3 aspect ratio.  Other exotic displays are available, but far out of reach for the average consumer.  Streaming services are a decade away but cable TV did have video on demand at extreme prices.

If you want music on the go, you will probably be using a portable CD player or cassette.  Records never really went away for home use, but most people listened to CDs at home.  For books, you bought them at a bookstore, or maybe Amazon, there were many bookstores at the time, or you went to the library.  E-readers will be coming, but nowhere in 1998.  If you wanted the news you could get it online, or watch TV news, or just buy a newspaper.  Most people still got their news via TV or the paper at the time.

Shopping was done almost entirely in real stores.  Department stores still ruled.  Shopping online at the time was pretty rare, except for Amazon and eBay.  In 1998 Amazon was an online bookstore, but not much else.  eBay was for everything else, and I remember using eBay, even back in 1998.  Anything household was still bought in real stores.  Electronics were at Best Buy, Radio Shack, or Circuit City.  This is also where you went if you wanted to purchase CDs, DVD’s, computers, and cell phones.  You did a lot of driving back then.  Speaking of driving, I hope you like paper maps.  Practical affordable GPS is a few years out as well.

The greatest change I have noticed in the last 20 years is just how connected and dependent we are on the internet.  Today, most homes have high speed, always connected internet.  All of our phones have high speed, always connected internet.  We order just about everything through the internet.  We pay all of our bills, talk to our family, read the news, watch movies, and 1,000 other things through the internet.  I don’t know if this is a good or bad thing, it is just different.  For anyone too young to remember 1998, it was a different time, but we still had the internet, we could still listen to music on the go, and still meet people on the internet.  I guess the real reason I look back on that time fondly is I really came of age in 1998.  I graduated from college in 1998.  I met my wife online in 1998.  We were looking forward to the new millenia.  Jobs were plentiful and real wages were rising.  Real changes were all around us.  We were looking forward, instead of backwards.

Facebooktwittergoogle_pluspinterestmailby feather
 

Posted by on August 10, 2018 in Computers, Social

Leave a comment