Yes Jim, a LOT of heat. There are also other chemical conditions that pertain. It's easy to find info about all this on Wikipedia and websites of the various companies that convert garbage to energy, as well as associations of those companies and organizations.
Thanks for clarifying, Ann – I was assuming the trigger was a particular temperature level, but then thought again that a bottle in a landfill, if buried deeply away from Sun & Weather, would mimic normal underground temperatures and hover around 55 degrees. But, on the contrary, I guess all that decomposition generates a lot of natural heat, doesn't it-?
As we've pointed out in many blogs, 3D printing is faster, less expensive, and less energy-intense for many aerospace applications. Another blog covered a study showing that it can be both cheaper and greener for consumers printing plastic items: http://www.designnews.com/author.asp?section_id=1392&doc_id=269539 So my point is that 3D printing is not monolithic. It depends on how one is measuring and what variables are being included. The problem with blanket statements about 3D printing being faster or slower, less or more green/sustainable, and less or more expensive than other manufacturing methods is that all of these can be true, depending on the process, materials, application, users, build volume, part quantities/build and total builds.
Jim, actually that Pepsi bottle wouldn't be at all confused: temperatures inside a backpack in a closet don't resemble temperatures in a landfill, which can be quite high. Biodegradable and compostable plastics are usually formulated to trigger breakdown when certain temperatures are reached, which only occur inside landfills under certain conditions.
Ann these are great points, and not easy solutions.Thanks for laying them all out on the table.
I see from the Sierra website where the design-intent of the chemical resin is to be susceptible to microbe enzymes found in landfills.I admire and support the engineering efforts, but clearly state the double-edge sword of "biodegradability", being that structural breakdown should not (cannot-!) begin while the product is still in its Use-Life-Cycle.
I think WilliamK made an excellent supposition, describing a back-pack hanging in a dark closet.I imagine a bottle of Pepsi in that back pack could be very confused as to whether it was still in its Use-Life-Cycle, or if it had been tossed into EOL status.
I think a real breakthrough might be if there was a locked enzyme within the resin compound that could be chemically released to trigger the start of the decomposition cycle, once the physical product structure were to be crushed, broken, or fractured.There is a missing link in this whole equation, being the catalyst to 'start the process'.
A good portion of my business is reasoning out the secondary and tertiary results of actions. Not that very difficult, sort of like the safety FMEA thing that some folks use. ZOnly it goes beyond that.
Good observation William. Here many laws are passed by voter initiative. Lots of money comes in for the campaigns, and emotions run high. Our legislature seems to rarely weigh all options, think long term, debate and pass laws.
I think if people were better informed, they'd make better decisions. I guess good information doesn't make a good campaign.
Nadine, California is one state where quite a few government decisions llok like they were made based primarily on emotions with little regard for facts. Of course that is seeing it from far away. Some states on the east coast are much worse for that, the closer to the capitol the worse off they are.
And it is primarily in the programs that try to do things that are not really government resposibilities that it gets worse and worse.
William, biodegradable and compostable plastics are often formulated to trigger breakdown when certain temperatures are reached, temperatures that only occur inside landfills under certain conditions. This company is known for making an additive that helps polymers break down, but not in any old landfills: specifically in landfills that are associated with landfill-to-energy operations. These are very different in several ways from open landfills used by consumers. Reuse and recycling are usually considered the first best option, but not all plastics are recyclable.
A slew of announcements about new materials and design concepts for transportation have come out of several trade shows focusing on plastics, aircraft interiors, heavy trucks, and automotive engineering. A few more announcements have come independent of any trade shows, maybe just because it's spring.
Samsung's Galaxy line of smartphones used to fare quite well in the repairability department, but last year's flagship S5 model took a tumble, scoring a meh-inducing 5/10. Will the newly redesigned S6 lead us back into star-studded territory, or will we sink further into the depths of a repairability black hole?
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.