technology – Page 2 – Geeky Girl Engineer

Bergen Sign Shop

Posted on October 30, 2014 by geek

Collection of old signs on the shop’s wall

I recently had a chance to tour New York City’s MTA’s Bergen Sign Shop. The Bergen Sign Shop is where all the signs for MTA’s subways are made and possibly a few other signs. The wonderful employees came in on a Saturday so that they could take two tour groups, from the New York Transit Museum, through the shop and show us how they make the signs. It was really neat to see and also interesting to hear how things have changed from the way things used to be made. Computers are now used for much of the process where as like many things, they used to have to be done by hand. Some of the signs they make are made like many of us make signs with regular ink jet printers, although they have massive printers with the biggest ink cartridges I have ever seen.

Safety first signs being printed in bulk. As an engineer, I particularly enjoyed seeing this.

All the “buttons”, the colored circles with the subway line letter or number, are printed on rolls of colored vinyl with adhesive backing. The line’s letter or number is then printed in black or white. A machine also cuts the circle into the vinyl, so employees just have to remove the excess from around the circles.

Rolls of vinyl in various colors ready for the printer. C line buttons being printed.

Drawer full of ready to go buttons. The buttons are made in 7 standard sizes.

They have another machine that just does detailed cutting of vinyl rolls. Once the vinyl has been cut, the excess is removed, and letters, numbers, and symbols are left in place. The letters are already spaced properly like they would be from a printer and are then transferred as a unit by an employee to a sign.

Roll of vinyl leaving the cutter.

The below, very short video is a series of photographs of an employee showing how he transfers the cut letters to a sign. The method he uses keeps all the letters spaced properly as they were spaced by the computer. The letters are transferred from the vinyl roll to transfer paper then to the sign.

Once the letters, buttons, etc. are on the sign, the sign is then laminated. It is later sent to the tin shop to be applied to a metal frame.

Sign being laminated

There is another machine that engraves signs and also applies to plastic beads to make braille signs.

Engraving machine

Temporary location sign with Braille.

In a separate room, they make frosted glass signs by applying a template and coating the glass with uv-activated substance. Ultraviolet light is then applied, and anything not covered by the template will be frosted.

Glass placed into machine where a vacuum will be applied and then it will be treated under ultraviolet light

Sign about to be treated under ultraviolet light

Sign being treated under ultraviolet light

Glass after being treated with uv light

In the back, they had the finished signs stacked up ready to be installed. They also had a supply of generic signs used in various places.

Spare generic signs stacked in storage

Finished signs ready to be installed

It was a really fun tour, and it was really neat to learn how the signs are made. Thanks to the New Your Transmit Museum and MTA employees for allowing us to take this tour and showing us how they do everything!

SAS Macro to Validate CAS Registry Numbers

Posted on June 25, 2014 by geek

*updated 7/20/15 after finding more ways people write CASRN or create fake CASRN that will sneak through my original macro*

I wrote a simple and fairly short SAS macro to validate CAS Registry Numbers. I have gotten enough free SAS advice and a few macros from various internet sources, so I thought it only fair to share this if it of use to anyone. Hopefully the comments give ample information about what input is needed and what the output is. The macro will catch an invalid CAS RN if it is

too long
too short
has all 0’s
does not return the correct check digit based on CAS calculation

Information about proper CAS RNs can be found from ACS who produce CAS RNs. Contact me if you have questions about the macro or find an error with it.

*macro to determine if a CAS number is a valid CAS number;
*input is name of dataset to be examined where CAS numbers have variable name CAS_number;
*returns valid = 1 if CAS is valid and valid = 0 if invalid CAS;
*returns character variable CAS which will be CAS number with hyphens and no leading 0s;
%macro CASnumber_check(CAS_dataset);
data &CAS_dataset (drop = CAS_num CASlength R N1-N9 QR Q Rcheck j);
length CAS_num $ 10;
set &CAS_dataset;
*give CAS numbers with alphabet characters or that are blank a 00-00 CAS number;
if CAS_number = “” then CAS_number = “00-00”;
if anyalpha(CAS_number) ne 0 then CAS_number = “00-00”;
*determine if CAS is numeric or character variable;
CAS_vartype = vtype(CAS_number);
*if CAS is numeric, converts it to character;
if CAS_vartype = “N” then CAS_num = STRIP(PUT(CAS_number, 8.));
*if CAS is character, removes all non-numeric characters;
if CAS_vartype = “C” then CAS_num = compress(CAS_number,,”kd”);
*breaks CAS number apart into digits;
CASlength = length(CAS_num);
R = input(substr(CAS_num,length(CAS_num)),8.);
QR = 0;
array N_(9) N1 – N9;
do j = 1 to 9;
if CASlength > j then N_(j) = input(substr(CAS_num,CASlength-j,1),8.);
else N_(j) = 0;
QR = QR + N_(j)*j;
end;
Q = int(QR/10);
Rcheck = QR – Q*10;
*checks on validity of CAS based on check digit and length;
if Rcheck = R then valid = 1; else valid = 0;
if N9 = 0
then if N8 = 0
then if N7 = 0
then if N6 = 0
then if N5 = 0
then if N4 = 0 then valid = 0;
if CASlength < 5 then valid = 0;
if CASlength > 10 then valid = 0;
*builds character variable called CAS with no leading 0s;
if N9 ~= 0 then CAS = cats(N9,N8,N7,N6,N5,N4,N3,”-“,N2,N1,”-“,R);
else if N8 ~= 0 then CAS = cats(N8,N7,N6,N5,N4,N3,”-“,N2,N1,”-“,R);
else if N7 ~= 0 then CAS = cats(N7,N6,N5,N4,N3,”-“,N2,N1,”-“,R);
else if N6 ~= 0 then CAS = cats(N6,N5,N4,N3,”-“,N2,N1,”-“,R);
else if N5 ~= 0 then CAS = cats(N5,N4,N3,”-“,N2,N1,”-“,R);
else CAS = cats(N4,N3,”-“,N2,N1,”-“,R);
run;
%mend CASnumber_check;

Photo Texting a Wrong Phone Number?

Posted on March 17, 2014 by geek

This evening someone texted me a photo that caused me to contact the police. I didn’t recognize the phone number, but according to a quick internet search, it is a Richmond, Virginia phone number. I have an iPhone, and the text says iMessage, so I am fairly sure the sender had to have been using an iPhone. There was no message, only a photo. The photo appears to be a child, maybe age 10. I am not sure if it is girl or boy. The photo appears to have been taken at a slight angle and shows the child’s face laying sideways on a (possibly) bed. There is an adult’s hand pressing down on the top of the child’s head with the thumb between the eyebrows pressing down hard enough to cause the forehead skin to bunch down below the thumb. The child is not smiling. The child’s mouth is slightly open, and while the child doesn’t exactly appear to be in pain, the child doesn’t look comfortable. The photo appears to have been taken in a house as I can see a bookshelf with framed photos in the background.

I didn’t know what to do when I got it, other than to take to Twitter to ask for advice. I finally decided to call my local police’s non-emergency phone number. The woman I spoke to asked what I wanted to do. I learned they have no way to receive a text message, so if I wanted someone to look at it, then an officer would have to come to my house. After deliberating, I finally asked to have them send someone. A very nice officer came fairly quickly, remarkably fast actually considering this was a non-emergency call. I showed him the photo apologized for making him come if he disagreed that it was somewhat disturbing. While he never actually stated what he thought of the photo, I think he agreed the photo was at best weird. Also he never gave me an impression that he thought I was a lunatic for being concerned about this photo. Unfortunately I learned there was very little, in fact nothing he could do. He said since the photo was not pornographic and did not show a child in imminent danger, cell phone companies would give them very little information without a court order. He also stated what I knew, which is that even the phone number appears to be Richmond, Virginia, the phone could be anywhere. He said with Google voice numbers, it might not even be a cell phone exactly. [It was not until after he left, I realized the text said iMessage, hence must be an iPhone.] I told him that I didn’t contact the phone number at all, partially because I didn’t know if this was a weird scam or what the proper response was. He essentially said there was nothing they could do now, but if I keep getting photos from this number, and they get weirder, to contact them again. For now, I will keep the photo and hope I don’t get anymore, that the child is in no danger, and that it was just a weird joke or something perfectly reasonable that got sent to the wrong number.

The incident brings up so many questions though. First, I live in a fairly affluent municipality that is not exactly desperate for money. Also, as a suburb of Washington, DC, public safety is generally not skimped on fiscally. So how is it in 2014, my police department can’t receive a text? Forget about how much easier it would have been for me to forward this photo to them, what about if someone is in danger? It might be easier and safer to send a text than to have to possibly reveal themselves by speaking on the phone to a police operator. Is this some sort of technological issue or what?

Second, I’m curious what other people would have done in my place. What other options are there? The police don’t seem to have many options in this case. I don’t want to over blow this photo because again, it’s not pornographic, and the child doesn’t appear to be in imminent danger, but still, it would at least be nice to track down a name or something to allow the police or someone just to phone them. I don’t know what I would even like to occur if anything was possible. I am not a fan of Big Brother, but I don’t like this feeling of helplessness.

Advice, opinions, comments, ideas, want to tell me I worry too much (yes I know that)? Please leave a comment.

Edited to add: Someone informed me how to get location data out of a photo. According the metadata on photo, it was taken in outskirts of Richmond, Virginia. I can narrow it down to a couple of blocks based on the way it is mapping. I think I will start paying attention to news from that area for a bit or possibly look to see if there are missing child cases or anything like that. At least I will feel like I did something.

Modern Child Meets Renaissance Art of Biblical Times

Posted on December 14, 2013 by geek

Today I toured a gallery of Renaissance art at the National Gallery of Art with a group from my church. A member of my church is a docent at the Gallery, and she graciously agreed to give us a tour of some art depicting the Nativity as a nice Advent activity. Most of the time, she gives tours for school groups. She told a funny story about when a six year old child was viewing a particular piece of art, “The Adoration of the Shepherds” by Giorgione.

“The Adoration of the Shepherds” by Giorgione

Here is a zoomed-in view of the lower right portion of the painting.

“The Adoration of the Shepherds” by Giorgione

The story we were told by our wonderful guide is that a six year old, while viewing the painting, innocently asked “what is Joseph texting?”

The child is observant. It does look like he is texting. Then again, maybe he tweeting, “today Christ is born.” Just think how much faster the Wise Men would have gotten there if social media had been around. Mary and Joseph could have checked in on Facebook or FourSquare. Think of all the Instagram images! As they say, from the mouths of babes, in this instance, about babes.

Book Review: “Conquering Gotham”

Posted on October 10, 2013 by geek

This isn’t really a proper book review but really more of a book recommendation. I’m not a writer or literary critic. I’m just an engineer who just finished reading a book about the history of one the greatest engineering feats in the early twentieth century and want others to know how interesting a book it is. The book is “Conquering Gotham: A gilded age epic: The construction of Penn Station and its tunnels” by Jill Jonnes (Penguin Group, 2007).

The book chronicles some of the history of various people and companies who tried to link Manhattan Island and New Jersey via bridge or tunnel. When the book starts, the Brooklyn Bridge, which was an engineering feat in itself, has been built, but the only railroad connection to Manhattan Island was via New York Central and its bridge over the Harlem River. Thousands of commuters, other people, and cargo must use ferries across the Hudson River everyday to get to Manhattan from New Jersey. Dewitt Clinton Haskin unsuccessfully attempts to build a tunnel underneath the Hudson River, but due to construction and financial problems, the tunnel was abandoned. [Decades later the tunnel would be completed and in present day is used for PATH trains.] Gustav Lindenthal unsuccessfully tried for decades to build a bridge across the Hudson River but was never successful due to an inability to get funding. Pennsylvania Railroad (PRR) under the leadership Alexander Cassatt is determined to get their trains into Manhattan in some manner instead of having their tracks end in New Jersey and their passengers needing to take ferries across the river.

The book describes how PRR explores the possible ways to get their trains to Manhattan Island and finally settles on an audacious plan to build two tunnels underneath the Hudson River, two tunnels under and through Manhattan, a grand station in a not so nice section of Manhattan, and four tunnels underneath the East River to further expand their tracks into New England. Completing this audacious plan is fraught with many engineering and financial difficulties and is further complicated by the need to deal with the corrupt New York City Tammany Hall politicians, which put about as many delays on the project as the difficult engineering. The history is fascinating, and Jonnes describes it really well. The book is not a dry history textbook. She describes the engineering obstacles in a way in which a non-technical person will understand and be interested, although as an engineer, I actually would have liked more details about some of the engineering issues, particularly with the tunnels.

The final chapter describes some of the post-completion problems, including the eventual decline of the railroads due to automobiles and then aviation. The modifications made to Penn Station after its completion and finally its destruction and replacement with the atrocious Madison Square Garden are also discussed. I have traveled on Amtrak trains many times via the Hudson River tunnels and twice via the East River tunnels. I have a much better appreciation for the difficulties in their construction now. I am also now even more sad to have never seen Penn Station in its original glory. In my humble opinion, the current Penn Station with Madison Square Garden is the ugliest and most ill-designed train station ever, and New York City deserves so much better. Of course, New York City is partially to blame for the destruction of the original and the construction of the current Penn Station.

If you are at all interested in history, transportation, or engineering, I highly encourage you to read this book. It is a great read. [I received no compensation for this recommendation, and I checked this book out from my local library.]

Inside a Water Filter

Posted on September 8, 2013 by geek

This is what happens when an engineer with an insatiable curiosity, power tools, and clearly too much time on her hands changes the water filter inside her refrigerator. Yes, that is pretty much it. There really is no other point to this post. Most normal people would take the old water filter and throw it away. I am not a normal person, and I wanted to see inside it, so I cut it open. Warning and reassurance to my mom: I wore a half-face respirator with PM10/VOC filters, goggles, and a leather glove while I cut through the filter. I strongly recommend if anyone else tries this, you do this also. I didn’t want to breathe in the dust or get it in my eyes.

Here is the filter before I began.

Photo 1: Used water filter for my refrigerator, side view

Photo 2: Used water filter for my refrigerator, top view

Here is the cross section after I cut through it length wise.

Photo 3: Water filter after length wise cut

The filter consists of a plastic shell that contains a hollow, round-bottom, cylindrical carbon filter. It is kind of hard to see, but the middle of the carbon filter is hollow. The carbon filter is held in the center of the plastic shell, so that there is free space all around the filter. Here are the two halves of the carbon filter side by side with inside of one shown on the left, and the outside of the other shown on the right.

Photo 4: Two halves of the carbon filter, showing inside and outside

As you can see the inside is still very black while the outside has started to gray. I have a hypothesis for the reason, which I will get to soon.

Here is the plastic shell with the carbon filter removed.

Photo 5: Plastic shell of the filter

Now here is a close up of the inside top of the plastic shell.

Photo 6: Close up of the inside of the top of the plastic shell of the filter

Notice how there are channels formed radiating from the center? The filter only has one opening, the hole in the center in the top, as is shown in the second photograph. Thus, one of the reasons I cut the filter apart was to try to figure out how it works. Water goes in through the center, but how does it get out? What follows is my engineering guess as to how it works. I am fairly sure the water comes in through the center hole, and the water pressure in the house forces it into the hollow center of the carbon filter and then through the carbon in all directions radiating outward. The water then is stored on the outside of the carbon filter until it is pulled by the refrigerator’s water dispenser or the ice maker. I think the white matter that has formed on the outside of the carbon filter that gives it a grayish appearance is calcium and magnesium, otherwise known as hardness. I live in Arlington County, Virginia, and our latest water report lists our water’s hardness as 125 mg/l. According to the United States Geological Survey, that puts our water as just in the hard range.

So if the water is stored on the outside of the carbon filter, how does it leave the filter to get to the water dispenser or ice maker? That is where I think those channels at the top of the plastic shell come in. In Photo 3, you can see the plastic top of the carbon filter fits flush with the top of the plastic shell, but the top of the plastic shell has those channels. Because of the space between the plastic shell and the carbon filter, the water can enter the channels from the outside then flow through the channels back to the hole in the center. However, the now filtered water does not flow back the same hole where the unfiltered water enters.The plastic tube at the top of the carbon filter prevents the filtered water from going back into the filter. Instead the filtered water leaves next to the center hole. In Photo 2, two rectangles can be seen next to the center hole, at approximately 1 and 6 o’clock in the photo. Those rectangles are holes, and it appears that the water that flows through the channels then can exit the filter through those rectangular openings. I can’t tell exactly this happens even though I examined where the filter attaches in the refrigerator. I did consider that perhaps I have the flow direction completely opposite, that is that the water enters through the rectangles, flows through the channels into the open space, then is forced through the carbon filter into the center of the filter. There are a variety of reasons, geometry, fluid dynamics, water pressure, etc., why I am fairly sure this is not the case.

So that is how my refrigerator’s water filter works. See this was educational. It was not just about me having fun with my Dremel rotary power tool and destroying something. Really it wasn’t.

Fitness and the Fitbit

Posted on July 7, 2013 by geek

I’ve had a Fitbit for about nine months now, and I get asked enough questions about my thoughts on it that I thought it would be most efficient just to write a blog post on it. Let me say clearly, this is not a sales pitch for Fitbit. There are other personal activity trackers out there, and here is a good summary and review of them. I have never tried any other one, but if you decide you want a personal activity tracker, research all the different ones.

First, for those who don’t know what a Fitbit is, it is essentially a really high tech pedometer. It keeps track of the number of steps you take and how quickly you take them, so it can tell the difference between when you slowly walking, walking briskly, or running. I have a Fitbit One, which can also determine how many flights of stairs I have climbed with a very tiny, sensitive altimeter. It calculates how many total calories you have burned by how active you have been, your basal metabolic rate, and your weight. The Fitbit has a simple display that shows that days total steps, stairs, miles, and calories burned. It is its ability to sync to the Fitbit system via your computer or smart phone app that really makes it high tech though.

On the website and to a certain extent on the smart phone app, you can see not only the stats that the Fitbit displays but also much more detail. It has a graph showing you how active you have been throughout the day. You can see all your data ever collected. For example, I can see how active I was six months ago and at what time of day. If you enter your weight manually or you use their Aria scale, then you can see all your weight data. You can log activities like yoga, running, gardening, etc. The activity logging helps to better calculate calorie burning as Fitbit will not know how much you are using your arms or other activities than walking or running. I exercise regularly on my elliptical machine, and it doesn’t really record my movement on it all that well, and it also can’t tell what kind of resistance I am using. I use the activity timer on the Fitbit to record the time I am on the elliptical machine, and then I use that information to log the activity on the website. Fitbit has a large database of various activities and how many calories on average you burn doing them. It uses the information you log to calculate the calories burned during that activity and overrides what it had originally calculated based on your movements it recorded. The activity timer is also nice when you are running or walking because it will use it to calculate your pace for that time period.

The Fitbit website and smart phone app also lets you record everything you eat and drink to calculate the calories you have consumed. It has a large database of food and their nutritional information. It has information on raw ingredients like apples or skinless chicken breast, and it also has information on processed or prepared food from big name brands and large food chains. You can also enter information based on nutrition labels.

If you enter a weight loss goal, Fitbit will ask how fast you want to lose it or conversely what kind of weekly calorie deficit you would like to achieve it. That is, as most know, in theory, you will lose one pound of fat with a 3500-calorie burn to intake deficit. Thus, if you consume 3500 calories less than you burn each week or 500 calories a day, then you should lose a pound a week. I say “in theory” because as any dieter will tell you, it is really not that simple. If you gain muscle, you could lose fat but still gain weight. Also, there is water weight that comes and goes, and then there is simply the “I have no explanation why I haven’t lost weight or why I have lost weight.” As a chemical engineer, the seemingly laws-of-thermodynamics-defying energy balance on my body is very annoying. Anyway, back to Fitbit, if you set a weight loss goal, it uses the calorie burned data it calculates to let you know how many more calories you can eat that day if you also enter all the food you eat. This is updated each time it syncs with the Fitbit, so after you exercise, it will show you how many more extra calories you can eat with this new activity information. Conversely if you are incredibly sedentary one day, the how many more calorie you can eat information will continue to decrease through the day. For example, based on my weight, my desired weight loss rate, and presumably my average daily activity level, each morning it starts out tell me I can eat about 2100 calories that day. As the day continues, if I keep a normal activity rate, i.e. walking here and there, the 2100 calorie will hold steady. If I sit like a lump all day, or the data just hasn’t synced, it might go down to 1700 calories or so. If I am quite active and then workout on my elliptical machine, it might say I could have eaten 3300 calories that day.

That’s a summary of what Fitbit does, and I would guess what other personal activity trackers do, so after using it for nine months, here’s what I think about it. I love it. Seriously, I love it. Granted, I am an unabashed data geek, so I love the data it gives me on myself. I think it is fairly accurate. In terms of tracking steps, it seems to need you to take at least five steps or so before it starts recording them. I have paced back and forth in a room with less than that, and it didn’t record anything. I am not sure of the exact number of steps it needs. It records flights of stairs accurately for the most part. It is supposed to record one flight of stairs for every ten feet climbed. In my two-story house, it is accurate, and in my office building, it records either one or two flights of stairs for every flight I climb because the floors are more than ten feet apart but less than twenty feet. When I notice that it is not recording stairs properly, I clean the Fitbit with some canned air. In terms of accuracy for calories burned, I have no idea how accurate it is. Based on my weight loss, I would say that it is probably fairly accurate.

As for whether wearing it everyday has changed my behavior, it definitely has. It is a reminder of how active or inactive I am. One of the reasons I first bought it was as I mentioned in a previous post, after moving to the DC area, I lost about 20 pounds without really trying because I adopted a pedestrian lifestyle. I bought the Fitbit to understand just how much walking I was doing. According to Fitbit and some other sources, you should try to take 10,000 steps and climb ten flights of stairs everyday. When I first started wearing the Fitbit, I found that I walked almost that much on a normal day without even exercising. I exercise almost everyday, so it became much more clear why I was losing weight. It was rather an eye opener when I went to Houston for Christmas a couple of months after getting my Fitbit. Even accounting for the fact that it was vacation, in Houston you drive everywhere. I had to make a very concerted effort to go for a walk in a park everyday to try to get 10,000 steps. Thus, it became clear just how much walking I do in DC relative to other places I have lived.

The constant count from my Fitbit has helped motivate me to keep increasing my activity level. If you are a competitive person, then friending people who also use Fitbit via the website may also help to motivate you, as on the website and app, how you rank in steps is shown in relation to your friends. Fitbit’s website also awards you daily and lifetime achievement badges for your steps, stairs, and weight loss. Each 5000 steps in a day gets you a higher badge and similar for the steps. This somewhat silly little badge icon on the website has managed to turn me into a 5 year old wanting another gold star, and I once found myself walking up and down my house’s staircase two times for no reason but for the sole purpose to get a higher badge. There is probably a bit of insanity or addiction that hits those of us who really get into the Fitbit. However the lifetime badges are a nice reminder of how much you have done. Because I also have Fitbit’s Aria scale, I get a badge for every five pounds that I lose, which is a rather nice reminder also.

My behavior has changed in very specific ways since I first got my Fitbit. About a month or so ago, I started going for walks during my lunch break at work. I actually really enjoy my walks now for various reasons, but it also gives me an extra half hour of brisk walking to add to my daily step count. At work, I also now regularly use the restroom on another floor to get a few extra steps and a flight of stairs. I now average about 18,000 steps per day, and I regularly climb over 25 flights of stairs per day. My pedestrian lifestyle has continued and increased. I enter everything I eat into the website, so it can tell me how many more calories I can consume. I have continued to lose weight.

Besides a continual reminder of your activity level, I think one way a personal activity tracker can help a person increase their fitness, is that it can help you figure out how you can achieve your goals whatever they are. There have been days when I have been pleasantly surprised that I have already accomplished quite a bit of steps, yet I haven’t gone for a walk or exercised. However, I was moving almost non-stop around the house doing housework, or I did several errands and parked at the back of the parking lots. Thus, the Fitbit helps me realize how small changes in behavior like parking at the far end of a parking lot can help to increase my fitness. Is that small action in itself going to cause me to lose a pound? No, but every little bit of lifestyle change can help.

A Fitbit is not a miracle cure for being overweight or a sedentary lifestyle. If you don’t care how inactive you are, then a constant reminder of your inactivity is not going to help. If you would like to become more active or figure out how much you can eat based on how active you are, then it can really help. It is a really nice tool, and like all tools, the usefulness and effectiveness of it, entirely depends on the user.

Solar Impulse

Posted on June 23, 2013 by geek

Solar Impulse, the solar powered plane that can store enough energy to fly through the night, is currently at Udvar-Hazy Center. The plane is a marvel of engineering both from the standpoint of being able to collect enough solar energy during the day to power itself all day and through the following night but also from the standpoint of being light enough in weight that it needs very little energy to keep it flying. I went to see it while it was open for public viewing Saturday, and from an engineering perspective, it is just beautiful. When viewed in person, you can see how the plane is covered in high strength fabric. In the back stabilizer, you can see the internal structures that give the stabilizer its shape. It is just an amazing vehicle. Note: If you click on any of the photos, it will open up larger in a new page to allow a better look.

front panorama of Solar Impulse

Side panorama of Solar Impulse

Solar Impulse cockpit and middle two propellors

view down the wing span

Tail and stabilizer

View of stabilizer from side showing internal support

View from below stabilizer showing internal supports and photovoltaic cells above

Solar Impulse wing flaps with photovoltaic cells on top

View between wing flaps using my zoom lens to show wires connecting photovoltaic cells

Industrial Waste Site Tour

Posted on November 29, 2012 by geek

I recently toured an industrial waste site where the groundwater underneath is being remediated for perchlorate contamination as well as other contaminates. Perchlorate can be naturally occurring, but in this case it is from historic rocket fuel and explosives manufacturing. The groundwater is being remediated partially through the use of bioremediation (i.e. microbes).

Lots of chemicals on site for the remediation, like ferrous sulfate.

Hydrogen peroxide

Nutrient for the microbes.

Lots of nutrients for the microbes

The label on this container notes the dangers of the concentrated phosphoric acid, which it contains. It also notes that there is a $800 deposit on the container, so you definitely want to remember to return the container.

The main part of the site is a series of fluidized bed reaction tanks.

With centrifugal pumps to keep the fluids moving.

More chemical storage tanks

At industrial plants, pipes always need to be labeled.

The first two mailboxes are labeled “PAP Sample to Lab,” and the second two are labeled “Clean Bottle Return.” I actually have doubts that these are really being used for pick up of samples to go to the lab. In general, samples need to be refrigerated once taken, and they should not be left in a metal box to bake in the hot sun.

Finally, always remember to drive slowly

Hoover Dam and Bypass Bridge

Posted on November 28, 2012 by geek

On my recent trip to Las Vegas, I made a trip out to Hoover Dam. As an engineer, I have an irresistible urge to visit important engineering landmarks. However, I don’t think you have to be an engineer to realize what a marvel the Hoover Dam is. Too many hardworking men died building it (one is too many though), and it has caused ecological problems by altering the flow of the Colorado River. However from an engineering stand point, it is an absolute marvel. The new bypass bridge next to it, more formally known as the Mike O’Callaghan – Pat Tillman Memorial Bridge, is in my opinion also a marvel and beautiful in its design. Part of the reason I consider both the dam and bridge to be marvels is where they were built, across the very steep, deep canyon of the Colorado River. The Hoover Dam was built with some really nice details that I have to wonder if most visitors appreciate or even notice. It was not just built as a plain hunk of concrete, especially on top where visitors walk. The bypass bridge was also built with some nice details, including many education plaques explaining how the bridge was built and why.

On a basic level, the Hoover Dam is a large block on concrete, carefully poured to hold back the Colorado River, and its adjoining power plant.

Actually, it is not a large block of concrete. It is a massive structure of carefully and individually poured blocks of concrete that form one connected structure.

It has its four connected intake towers to bring the water to the power plant. The intake towers were nicely designed in an art deco style.

Lake Mead water level has been dropping, so currently the Arizona overflow spillway is entirely out of the water.

A plaque on the dam marks the state line between Nevada and Arizona and notes that the American Society of Civil Engineers has selected the Hoover Dam as one of seven modern civil engineering wonders.

On top of the dam are restrooms. Here is the women’s restroom which has quite the entrance.

Here is the floor of the women’s restroom. Presumably the men’s restroom has a nice one too, but I wouldn’t know.

The designers really liked brass doors. I am not sure where this brass door leads since you can longer enter the dam the way the way you could when it was originally built.

If you stand in front of the door at the right angle, at the right time of day, with the right sunlight, you can see the intake tower on the other side of the dam reflected in the door. Look near the top of the door, and you can see the reflection of the blue clock near the top of the intake tower.

An upclose photo of the post top in front of the door in the above photo. They put brass prickly pear cactuses on top of the posts. I love that level of detail.

In the reflection of this door’s window, you can see Lake Mead.

I don’t actually know what this is, but it is on top of the dam. I thought it was kind of interesting, and also it has the name of another state besides Nevada and Arizona on top of the dam.

At the bottom of the dam, of course, is its power plant. Below, as seen from dam.

The view from the bridge of the power plant.

The power plant requires a jungle of transmission lines.

The relatively new visitor’s center, new compared to the dam, was also built in a ridiculous position on the shear canyon walls.

The bypass bridge sits high above the power plant.

It gracefully crosses the canyon.

The pedestrian walkway of the bridge has nice markers to denote the state line and apex of the bridge, which are in two different spots.

The path to the bridge passes through a rock cut where each side is lined with rock stabilization bolts, which I personally think are really cool looking.

Finally, one last look at the Hoover Dam with the shadow of the bridge across it, and the moon rising in the sky.