Monday, October 29, 2012

Apple #608: How Baseballs are Made

There is a ton of stuff going on this week.  Any number of things that your Apple Lady could talk about.
  • The Presidential election is coming up, so I could talk to you about how wonderful a thing it is that we in this country get to vote and that our votes actually do count, and how important it is to vote.
  • Next week, Daylight Saving Time will end and we'll have to move our clocks back one hour. Most of you are probably cranking up your furnace with the onset of colder temperatures.
In case you haven't guessed, I have covered all these topics already.  So what's an Apple Lady to do?

Naturally, talk about baseball.

In addition to everything else I've listed, the World Series is also going on.  I want the Tigers to win, and since it's tied in the 9th and the Giants are up 3-0 in the series, it is not looking good for the Tigers.

I don't want to jinx the Tigers, so I'm going to talk about baseballs in general.  You  know, the balls themselves.  How they're made.

The inside of a baseball, deconstructed.
(Photo from Wired)

  • From the inside out, baseballs are made of a pill, which is a ball of cork with rubber padding around it, then wool fibers wrapped around that, and two pieces of cow hide that get stitched together.

Here's the cross-section of showing all the ingredients inside a baseball.
(Image from Baseball Fever)

  • Every component inside the baseball is made to very precise specifications.
  • The cork at the very center weighs 1/2 ounce and measures 13/16'" in diameter.  Cork is used at the center because it is "livelier" than a rubber core.

[Scutaro just got a base hit for the Giants and the man on base scored. Giants are up 4-3 in the 10th.]

  • Around the cork are two layers of rubber, one black and one red.  They added the rubber to cushion the cork and help it last longer.
  • The black rubber layer is actually two hemispheres that are joined together by red rubber washers. That why, in that cross-section up above, there are red notches extending into the black rubber layer.
  • The black and the red layers of rubber weigh 7/8 ounces each.
  • The cork plus the layers of rubber measure 4 1/8" in circumference.
  • Latex adhesive is added to the cork + rubber, which is called the pill.
  • Wound around the rubber are four layers of wool yarn.  The first layer uses 121 yards of the thickest type of yarn, which is four-ply, and gray.  When the 4-ply yarn is wrapped around the interior, the circumference of the ball expands to 7 3/4".
  • The second winding uses 45 yards of 3-ply wool yarn that is white. (The colors are different just to distinguish the different thicknesses of yarn and the windings.)

[Jackson strikes out. Out #1 in the 10th for the Tigers.]

  • The third winding uses 53 yards of 3-ply gray wool. At this point, the ball measures 8 3/4" in circumference.
  • The fourth and final winding doesn't use wool but rather white poly-cotton yarn because the fibers are finer and smoother. 150 yards of it.

[Don Kelly, in his first appearance in the World Series, strikes out.  Now Miguel Cabrera is up.  He's the biggest batter for the Tigers.  Won the Triple Crown this year.]

Here's another cross-section showing the inside of a baseball.
(Image from Science Proficiencies)

  • The windings are done using computerized, high-tension machines which maintain a constant level of very high tension so that some spots don't get wound tighter or more loosely than others.
  • After the 4 windings, the whole thing is dipped into rubber cement to seal the deal.  At this point, the ball weighs 4 5/8 ounces.

[Miguel Cabrera just struck out.  Giants won the World Series.  In 4 straight games.  Sigh. But never fear. Your intrepid Apple Lady will press on.]

  • Next comes the outer layer.  It is made of -- get how official this is -- Number One Grade, alum-tanned, full-grained cowhide, primarily from Midwest Holstein cattle.  This particular type of cattle is preferred because their hides are considered to be smoother, cleaner, and with a better grain than cattle from other parts of the US.
  • The hide must be white.  It is punch-cut into two figure-8 patterns.  The cowhide gets moistened slightly to make them easier to work with, and more rubber cement is applied to the interior to make them stick to the woolly ball.
  • Once the two pieces of cowhide are stuck to the ball, they get stapled and then hand-sewn together using 88 inches of waxed red cotton thread.  Some say there are 108 stitches with the first and last stitches completely hidden, presumably so the stitches don't come undone.
  • It takes about 13 to 14 minutes to do this hand-sewing of one baseball.
  • When the stitches are done, the staples are taken out.  The ball is rolled to make it smooth, and then it gets inspected, weighed, and measured.  It must weigh between 5 and 5 1/4 ounces and measure 9 to 9 1/4" in circumference.
  • If it passes inspection, it gets stamped with the trademark and all official insignia and it's packaged up for sale.

Here you can see the whole process in action.  I love these how-it's-made kinds of videos.

  • A baseball must keep its round shape even after being hit 200 times by a 65-pound force.  One way they test this is to compress the ball between two anvils (the coyote would be proud!).
  • Despite its durability, the average Major League baseball gets used for only 5 to 7 pitches in a Major League game.
So now, in addition to knowing how baseballs are made, you also know to check the Daily Apple for background information on all the current news stories of the day, and also for occasional play-by-play descriptions of her preferred team losing badly.

How Products are Made, Baseball
Baseball Fever, Inside a Modern Baseball

Sunday, October 14, 2012

Apple #607: Felix Baumgartner

Everybody is talking about that jaw-dropping free-fall from the stratosphere that Felix Baumgartner accomplished successfully today.  I didn't know anything about this until after it happened.  Naturally, while reading the news articles, I wanted to know, who is this guy?

Felix Baumgartner, at the start of his free fall from the stratosphere.
(Photo from Wired)


First, a few statistics about his jump.  Some of these numbers have yet to be verified, but these are the unofficial numbers currently being reported.
  • Baumgartner was the first sky diver to break the speed of sound.
  • He reached a top speed of 833.9 mph, or Mach 1.24.
  • The ascent took 2 hours and 21 minutes. Total time of descent: 9 minutes, 3 seconds.
  • Total distance traveled in descent: 24.2 miles
  • He also set a record for the highest free fall, from 128,097 feet.
  • The time he spent in free fall (before his chute opened) was 4 minutes 20 seconds, just 16 seconds shy of the record held by Air Force Col (Ret) Joe Kittinger set 1960.
  • The jump was performed from a space capsule in the stratosphere over Roswell, NM.
  • Since he got up there in a capsule lifted by a helium-filled balloon, his first record set was for the highest manned balloon flight.
  • He was wearing a pressurized suit that also protected him from the very cold, near-vacuum of the stratosphere.
  • Today, October 14, 2012, is the 65th anniversary of when Chuck Yeager first broke the sound barrier in the Bell X-1 rocket.

Here is video of the jump beginning just before Baumgartner leaves the capsule.  When he pushes himself out into space, I clutch myself in terror.

For more video, The Washington Post has video from CBS News that they've excerpted to show the highlights from before his take-off, through the ascent, the jump itself, the descent, and the landing.

This photo was taken on one of the days when the jump had to be canceled because of a dust devil in the area. You can get a good look at that pressurized suit here, though.
(Photo from Felix Baumgartner's Facebook page)

  • He said the thing that bothered him the most wasn't the height or the fall, but the pressurized suit & helmet.  He suffers from claustrophobia. When he put on the suit, he could barely stand more than a few minutes in it.  He said that when the visor closed, he got a feeling of "nightmarish silence and loneliness."


Now, about Felix.

This is Felix Baumgartner looking very tough-guy severe.
(Photo from Felix Baumgartner)

Here's the more relaxed Felix on Catalina Island.  I think that statue is of a seal.
(Photo from Felix Baumgartner)

  • 43 years old. Born April 20, 1969.
  • Born in Salzburg, Austria, now lives in Switzerland.
  • Made his first skydive at 16. 
  • He has a girlfriend.  Just in case you were wondering.
  • He's a former paratrooper for the Austrian military's Special Forces unit. 
  • After he left the military, he made his living repairing motorcycles while continuing to skydive.
  • He makes his living now as a stunt coordinator, operating freefall cameras, and as a commercial helicopter pilot.
  • He also says he is a professional B.A.S.E. jumper.  I didn't know you could get paid for that.  I guess, since Red Bull is his sponsor, he does.  Regardless, he obviously enjoys doing it. 
  • Other records he's set: lowest B.A.S.E. jump from Rio's Christ the Redeemer statue, 2-time record setter for highest B.A.S.E. jump from a building, and once landed with a chute inside a cave in Croatia.
  • On his website, he makes a lot of references to 502. He's made a logo of it, and he's got a tattoo of the logo.  502 is his B.A.S.E. jumping registration code. 

Here's Felix, sporting his 502 tattoo, and getting a medical check before a jump.
(Photo from Felix Baumgartner)

  • B.A.S.E. jumping is a very dangerous sport of using a parachute to jump from fixed objects.
  • To get your official B.A.S.E. jumping registration code, you have to jump from objects in each of the four categories:
    • B = Building
    • A = Antenna
    • S = Span (bridges)
    • E = Earth (cliffs)
  • Here's what the B.A.S.E. organization says about itself: " does not recommend anybody to get into BASE. It takes a certain type of person to become a BASE jumper and more likely than not, you are not that person."

This is the image Baumgartner has posted at the top of his blog.
(Image from Felix Baumgartner)

  • “Trust me, when you stand up there on top of the world, you become so humble. It’s not about breaking records anymore. It’s not about getting scientific data. It’s all about coming home.” -- Felix Baumgartner

Edit: February 2014, GoPro has released the video of their what their 7 cameras on his body caught as he fell.  There's some preliminary stuff, but the real thing starts 52 seconds in.

Felix Baumgartner's blog
Felix Baumgartner's website
Red Bull Stratos, Felix Baumgartner
Chuck Squatriglia, 'Fearless Felix' Falls 24 Miles to Earth, Wired, October 14, 2012
John Tierney, Daredevil Jumps, and Lands on His Feet, The New York Times, October 14, 2012
AP via The Washington Post, Skydiver lands smoothly after daring 24-mile leap; officials say he broke sound barrier, October 14, 2012 

ABCNews, Felix Baumgartner Beat Claustrophobia in Record Sky Dive, October 15, 2012, Getting into BASE

Monday, October 8, 2012

Apple #606: School Photos

I don't know if this still happens in schools as much anymore, but I remember fall and back-to-school as  being the time for school pictures.  It seems to me that the practice of schoolchildren getting their portrait taken by some photographer who shows up one day a year, and then the parents purchasing several copies of that picture has become pretty much ensconced in our culture (at least, until digital cameras and Flickr and Facebook made that practice of less value to parents).

So my question is, how did this practice get so established that we pretty much take it as a given that somebody is going to show up at school and take pictures of every single kid in school, and then sell those photos to the parents?

This poor girl looks like she has no idea what has happened to her, why someone has dressed her in that way-too-big cap and gown, and put her in front of that stupid background. Hey, it's a class photo. We all look weird in those things, it's just a question of degree.
(Photo from AMC School Photography Service)

  • It turns out, the practice of taking school pictures starts with pretty much one photographer, George K. Warren in the late 1850s.
  • George had a photography studio in Lowell, Massachusetts which he opened in 1851. He was producing his photos using the Daguerreotype method. 

This now-famous photo of Edgar Allen Poe is an example of a Daguerreotype. You can't tell from this version of it, but Daguerreotypes have an almost hologram-like quality. This is because of the highly-polished, reflective nature of the silver on which it is made.
(Photo from Wired)

  • Daguerrotype photography, by the way, meant you had to take a copper plate which was coated with silver, polish the silver until it was smooth as a mirror, put it in a closed box with some iodine, and then you could use it to take the picture.  After you took the picture, then you have to develop it over a pool of hot mercury, and then fix the image using some chemicals, one which included gold.
  • So that was an expensive process, it was time-consuming, and it was dangerous (though they probably didn't know that at the time).
  • After running his studio the Daguerrotype way for a few years, Warren decided to switch to a new, different process which used glass negatives.  He wasn't the only one making that switch, but what he did with the process was different.
  • With a Daguerrotype, you had one image and one print.  Negatives meant you could make several prints from one image.  
  • George asked himself, who would want several copies of the same photo? His answer? Schools! (well, specifically, colleges.) This wasn't too much of a leap, since he lived near Boston and you practically couldn't swing a cat without hitting a college. 
  • But he thought that students graduating from college would like to take pictures of their classmates back home with them.  So he created photo albums, one photo per page, of the students graduating that year.  (Yes, this is also the story of the first yearbook.)
  • He made arrangements with all sorts of colleges and universities -- Harvard, Brown, Williams, Rutgers, Union College, Phillips Academy -- that they would buy a minimum number of his photo albums.  Then he set up appointments to take portrait photos of students, their professors, the college presidents, even the housekeepers.  He also took photos of the buildings and grounds.

Photo taken by George K. Warren of the grounds at Harvard University in the early 1860s.
(Photo from Luminous Lint)

  • (Recognize the business of a photographer from elsewhere making appointments with lots of schools ahead of time?  Securing commitments that people will buy so many photos before the photographer even shows up?)
  • After taking the photos, Warren went back to his studio in Lowell, produced the photos from his negatives, trimmed them, mounted them on individual pages, and sent them to a bookbinder to be bound. The bindery also embossed the name of the school on the cover, and in some cases, added the name of the student who would be the purchaser of that album.
  • How do we know all this?  The Smithsonian has one of those photo albums of George K. Warren's.  That particular album belonged to George W. McNeel, a Rutgers student whose senior year was 1859-1860.

George W. McNeel, in his 1859-1860 Rutgers yearbook, photo & album made by George K. Warren
(Image from the Smithsonian

  • In true yearbook fashion, people signed it.  Except they didn't write messages like, "Have a good summer," or "Party hardy."  Their messages were more like letters.  And they were written by classmates and instructors both.
  • Something else a little different about this yearbook was that George Warren included a photo of himself. 

Photo of George K. Warren, the photographer who took the pictures in George McNeel's Rutgers yearbook, complete with this inscription: "Photographically I am yours, my dear McNeel. Geo. Kendall Warren." 
(Image from the Smithsonian)

  • His idea really caught on.  At one college in one year, he made over $1,000. In today's money, that would be $3,700. From one school. And he visited several, each year.
  • Today, following in Warren's footsteps, photographers who work for a company or studio (Lifetouch may be the largest; they photograph some 20 million students each year) make arrangements ahead of time with several schools.  These companies aren't visiting colleges as much as they are going to grade schools and middle schools, but it's the same idea.  

Here's one delightful class photo from the archives. Sadly, I don't know her name. Or the name of her hairdresser.
(Photo from Blogging Bistro

This yearbook photo is of someone currently famous.  Any guesses? Answer at the end of the entry.
(Photo from the angry dome)

Sooner or later, everybody makes the dorky-class-photo face.
(Photo from a page of nothing but photos of some kid named Nick)

  • Today's school photographers sit the students down in front of a fake backdrop, tell them to smile, and take their photos.  One at a time.  That's about the same as the way George Warren did it, too.
  • They do now manage to take everybody's picture in a day or two.  That's probably a lot more pictures in a lot less time than George Warren did it.  But the multiplicity of it is similar.

Do they still do these class composite photos?  I hope so.  This one is from Mr. Fine's 8th grade home room, Newton Elementary School, Torrance, CA, 1969.
(Photo from Gary Chang's Scrapbook)

  • Today, it's not the students buying the photos but rather the parents.  And, from what I've read, some parents are less interested in the class photos now because they've got scads of pictures of their kids, now that just about everybody has a digital camera.

Then there's the technological advancement of superimposing two images in the same print, which allows for wondrous photographic achievements such as this. 
(Photo from
  • But, some parents say, they don't actually have any on-paper photos of their children.  So they like the class pictures because they get an real, tangible print of their child that they can put in their wallets or prop up on the mantelpiece.
  • Wanting a photo of someone you care about -- that hasn't changed at all.

This is Jia Wen's school picture. I think this one turned out pretty well.
(Photo from A Mum's Hideout)

The mystery yearbook photo is of Joe Biden.

Shannon Thomas Perich, Photographic History Collection, Smithsonian National Museum of American History, "Photography Changes How We Choose to Recast Experience" (it's actually about the history of George K. Warren's photo albums)
Library of Congress Memory Project, The Daguerrotype
Skinner, How to Identify a Daguerreotype
Katherine Rosman, It's Picture Day, Say 'Cheesy', The Wall Street Journal, November 10, 2011
Historical Value of the US Dollar

Monday, October 1, 2012

Apple #605: Microwave Steam Bags

I have a request!  Daily Apple reader Rodolfo wants to know about those plastic bags that are specifically used for steaming frozen vegetables.  He wants to know how they work.  He suspects they're different from a typical plastic storage bag, but how, exactly?

Rodolfo was even kind enough to send me a picture of the type of steamer bag he uses.
(Photo from my friend Rodolfo [his name has been changed to protect his innocence.])

I suspected the answer to Rodolfo's question would require a patent search, and I was right.  But, never fear, when it comes down to it, how those bags are put together is pretty easy to explain.  And the best way to explain how they work is to explain it in terms of how they are different from a regular old sealable (or zippable) plastic storage bag.

Regular plastic storage bag on the left, zippable plastic steamer bag on the right.
(Photo from Cross My Heart)

  • I should admit right up front, I've never actually used plastic steamer bags.  I steam my vegetables the way my mom taught me, in a pot of water with a steamer basket.  But in order to answer Rodolfo's question, I read a lot of people's descriptions about how they work.  I'm a little nervous generalizing on the basis of read-it-only, but I'll do my best.
  • First, the plastic in the steamer bags is made of materials that won't leach toxins into your food when microwaved.  Whew!  Specifically, the Ziploc bags are made from polypropylene (PP #5) and polyethylene (PET #1).  
  • The bad plastics we've heard about recently are bisphenols (BSPs).  The steamer bags do not contain those kinds of plastics.  
  • So, the fact that the steamer bags don't have the bad plastics in them doesn't seem to make them all that different from a typical storage bag.  So how else are they different?
  • If you've ever compared a freezer storage bag to, say, a sandwich storage bag, you would have noticed that the plastic in the freezer storage bag is much thicker.  In order to withstand the temperatures in the freezer, and to resist getting torn or broken if the bag gets knocked around, the plastic is made of several layers of plastic.  There might be two or three layers of plastic, depending on the manufacturer, and the layers might be of different types of plastic that are tolerant of various temperatures.  The outside layer, for example, might be able to withstand colder temperatures than the inside layer.

Thicker freezer bag on the left, thinner sandwich bag on the right.
(Freezer bag photo from Made in, sandwich bag photo from Industrial Laboratories)

  • The same is true about these steam bags.  The plastic is thicker and it's usually made of layers.  The difference is with the steamer bags is the inside layer has to withstand a melting point, because the stuff inside is going to get really hot when it's heated in the microwave. 
  • Fortunately, since cooking times are relatively short, it doesn't have to be able to stand the heat for very long, but it does have to hold up to high temperatures.
  • If the bags are designed to go from freezer to microwave, then the bag is probably going to have more layers, or the plastics will be a little different because they will have to be able to hold up under the cold temperatures of the freezer, and not get torn or broken during transport.  
  • But the upshot is, the steamer bags have multiple layers of plastic, and the layer inside has to be able to withstand higher temperatures.
  • The next big difference is the steam bag has to have a way to release the steam.  If you put those vegetables in the microwave and sealed them up tight with no way for the steam to get out, the package would explode, and you'd have pulverized broccoli all over the inside of your microwave. 

The problem for steamer bag makers: how to let out the steam so the bag doesn't explode, but not let out so much that the vegetables don't actually steam?
(Photo from dipity)

  • If you told the consumer to puncture the bag before microwaving, as we all have done with frozen dinners, that still wouldn't be ideal because the hole would allow too much moisture to escape during cooking, and the vegetables wouldn't really get steamed.
  • So the plastics people came up with a pretty ingenious invention: the vent.  The Ziploc bags have a vent across the top, other types of bags have vents that appear across one side of the bag, and still others have the vent set up differently.  But they mostly use the same general idea.
  • The clever thing is, the vent doesn't open up until the package is being microwaved.  Exactly how the vent works depends on the manufacturer and the patent, but here's a description of how one company does it.  This isn't from the patent for Ziploc's bag, so how theirs works might be a little different than this.  But it's probably close.
  • The plastic in this steamer bag has two layers, and outer, protective layer, and an inner, heat-friendly and sealable layer.  The inner layer is doubled up and sealed to itself, so the inner layer now has two layers.  The outer, protective layer is on top of the inner, doubled-up layer.
  • The vent is made by making an opening in the seal of the doubled-up layer.  That could be done either by not sealing it in one spot when they double it up, or by cutting a slit in it after it's been sealed.  Either way, there's a slit in the doubled-up inner layer.  The outer, protective layer is still on top of the inner layer.
  • When the bag gets put in the microwave and heated up, the inner, doubled-up layer is not bothered by the heat because the plastic was made to withstand high temperatures.  But the pressure that builds up inside the package pushes the plastic from the inside so that it bulges, which, in turn, makes the vents in the inner layer open up.  Because the outer protective layer is not as good at holding up to the heat,  the outer layer opens and, voila, the steam escapes.

Ziploc steam bag after cooking. The thing has bulged and filled with steam, only some of which has escaped. The rest has stayed in the package and steamed the vegetables.
(Photo from Cyber Shape Up)

  • That's why it's important to put the bag in the microwave with one side in particular facing up.  That's the side with the vent in it.  You put the vent-side facing down, you might block the vent, and then you'd get pulverized broccoli.
  • That vent-in-the-inner-layer method is not how everybody does it.  Some people cut slits through all the layers from the get-go, and they make the slits small and spaced far enough apart that they think they can keep too much moisture from escaping.
  • There's still another method of using a breathable patch in the plastic.  The patch is, itself, made of plastic, and it lets the steam out, but it's not porous enough to let water or anything else out.  In that case, you would peel away a protective sticking covering over the patch before microwaving.
  • But as far as I can tell, the inner layer with a slit in it might be the more popular method.
  • Now, I can't resist saying this: these steamer bags are made of plastic, which is made from petroleum.  You use the bag once and you have to throw it away.  I suppose you could try to use it again, but the plastic might degrade with the increased use and heat, and the vent system might not work properly, and nobody's tested these things for multiple uses to determine if you'd get toxins in your food, so it's just a bad idea to use them several times.  They're meant to be disposed of after one use, so if you use them, that's what you should do.  

That plastic steam bag came from petroleum.
(Image from Highlights)

  • I use a steamer basket to steam vegetables.  You might say, Aw, but that takes time!  Dude.  You cut up the broccoli while you boil the water.  You put the broccoli in the steamer basket, put that in the pot of water, put the lid on top.  Two minutes later, it's done.  Same amount of time's passed.  And you haven't used any plastic!  You've saved that petroleum for your car!

Steamer basket. You can buy one like this for $4.95 from Amazon, or you can find them hanging around in any grocery store, or at any store like Target or Wal-Mart, or any store that sells any kitchen stuff.

  • If you don't like the environmentally friendly argument in favor of using a steamer basket, how about this one: the food and plastics companies are ripping you off.
  • I used to research the agriculture and food manufacturing industry, and I can tell you that food processors are always looking for a way to get you to spend more money on food.  There's no margin of profit on a bunch of asparagus.  But if they can cut up the asparagus for you, freeze it or can it, and put it in a pretty package, they can get you to pay a lot of extra money for that asparagus. 
  • You might say, But I'm not buying the Birds Eye pre-packaged stuff, I'm just buying the bags and freezing and steaming my vegetables myself!  To that I say, Ziploc is just trying to get in on the action.  You have to buy the steamer bags every time you want to steam something.  You buy the steamer basket once and you're done.
  • You might say, But I don't know how to use a steamer basket! Dude.  It's easy. It's so easy, about 15 people have written how-to pages about it. Here's one such page of instructions.  The only question is, how long do you steam different kinds of vegetables?  After a couple minutes, lift the lid and poke 'em with a fork.  If they give, they're done.  If they still feel crunchy, they're not. Put the lid back and wait a couple minutes more. When you can smell the vegetables, lift the lid and poke 'em again.  They're probably done.
  • I'm all in favor of convenience.  I think this vent invention is really pretty dang clever, and I applaud whoever came up with it.  But it seems to me, in this case, the convenience isn't that much of a time savings, and it's certainly not a financial savings.  I think we as a country have bought this steamer bag scam, hook, line, and sinker.
  • That's just my opinion.

The people who make these things look at this steamer bag trend and think, "Cha-ching! What an easy way to make some extra bucks!"
(Green Giant vegetables, Red skin potatoes with free microwave steam bag! photo from Packaging Digest, Birds Eye vegetables and rice, Kashi's entire meal in a steam bag photo from Supermarket News, Ziplog steam bag photo from The Nibble)

Dr. Weil, Plastic Steaming Bag Danger? February 26, 2009
Florence Williams, Is It Safe to Heat Food in Plastic? Good Housekeeping
Lauren Keith, Two Microwave Steam Bags--Which is Better? KFVS
Joe Terrell, Ziploc Zip 'N Steam: "Does It Work?" KLTV, July 31, 2007
Steaming Splendor: Easy, Convenient, Tasty Steamed Vegetables, The Nibble
Su, Jau-Ming and Wolak, Paul Z., Freezable/microwavable packaging films and venting package, US PAT 7,812,293, October 12, 2010
Mita, Kozo et al., Sealable package for heating in a microwave oven, US PAT 6,596,355, July 22, 2003
Bemis Introduces Hermetic, Steam-in-Bag Package Technology for Meals that Include Proteins and Sauces, Bemis Company, October 10, 2008