The Naked Scientists

The Naked Scientists Forum

Author Topic: Tessellated I / H tiles / bricks  (Read 17178 times)

Offline Peter Dow

  • Jr. Member
  • **
  • Posts: 42
    • View Profile
    • Scottish National Standard Bearer
Re: Tessellated I / H tiles / bricks
« Reply #25 on: 13/01/2013 00:38:34 »
Sorry, I didn't make a comparison of different spray foams.  But, I didn't find the firestop very fireproof.  This was a burn test I did a couple of years ago.  It was easy to light.



I think the idea is that if you fill a crack, it will slow down the progression of flames and smoke through the crack, but it will certainly burn quite nicely.
Burns "nicely" so long as no-one is breathing in the fumes.

Quote
Wikipedia: Polyurethane - Health and Safety [nofollow]
Polyurethane polymer is a combustible solid and can be ignited if exposed to an open flame. Decomposition from fire can produce mainly carbon monoxide, and trace nitrogen oxides and hydrogen cyanide. Firefighters should wear self-contained breathing apparatus in enclosed areas.
Yet that is supposed to stop a fire spreading?

Out of interest, did you just spray it and light it immediately or leave it for a time to set, if so for how long?

I ask because I read a website that said their product is supposed to set over time by reacting with moisture in the air. Possibly when it comes straight out of the can it is a lot more flammable than it is after setting?

Not that I am recommending this product. I am with you if you are questioning its utility.

« Last Edit: 13/01/2013 00:45:28 by Peter Dow »
 

Offline Peter Dow

  • Jr. Member
  • **
  • Posts: 42
    • View Profile
    • Scottish National Standard Bearer
Re: Tessellated I / H tiles / bricks
« Reply #26 on: 13/01/2013 02:34:18 »
There are many different types of floods.

In the Northwest USA, the floods are characterized by fast moving water, capable of ripping houses from their foundations, and certainly not safe to casually walk in.  The 1964 Rogue River flood had a depth of about 10x the normal river depth, 68 feet at Agness, 50 feet above flood stage, or about 4x what is considered flood stage, and flows exceeding 100x the summer flow rates.  And, no dam failures.

Mississippi River floods may be slower moving. 

Although, there still may be periods of rapid inundation as dikes fail, followed by slow moving water once a basin fills up.

I presume that during flood periods, most people simply move away from the water.  I'm surprised of the number of people walking around in the  Bangladesh flood above.



Well I am no expert on Bangladesh but I can read that the floods there can inundate 50% or more of the land area and so maybe 30 million homes are flooded and people may be 50 miles or more from any dry land and my guess is that their local and national authority emergency relief services can't cope and so people are left to fend for themselves at least until the news photographers turn up, hopefully soon followed by the international aid agencies.

The problems with shelter comes as people return to their homes.

A simple concrete structure may be able to withstand the flooding, although one of the issues noted in New Orleans was that mold became a significant issue, and much of the insides of the houses needed to be gutted and rebuilt, or even the whole houses torn down after the flood.

It may be more intense building, but some houses may be built on stilts, or in rural areas, perhaps building a small hill for the homesite which then remains as a small island.

For slow moving flood prone areas, It would be easy enough to build a house with wood, or hollow skids underneath it, and chained down to prevent it from floating away.  Of course, being careful of boyancy/weight of construction materials.  For a high flow area, a floating house may still sustain significant damage.
Well not all houses can survive a collision with what the flood brings to its door, or its roof.


A ship was washed onto a building when the city of Otsuchi, Iwate Prefecture, was hit by the tsunami.

For this kind of strength I don't think expanded polystyrene can help us. I / H bricks made of reinforced concrete could do that boat-on-the-roof job though.
« Last Edit: 14/01/2013 23:40:04 by Peter Dow »
 

Offline Peter Dow

  • Jr. Member
  • **
  • Posts: 42
    • View Profile
    • Scottish National Standard Bearer
HI-BRICKS & DOWELS demonstration video
« Reply #27 on: 14/01/2013 15:21:42 »
HI-BRICKS & DOWELS demonstration video by Peter Dow (YouTube) [nofollow]

Transcript of the video



Hi everybody and welcome to my "H" / "I" Bricks or HI-BRICKS & DOWELS demonstration video.

This is Peter Dow from Aberdeen, Scotland.

There are two components to a HI-BRICKS & DOWELS construction -

  • the BRICKS, which you can either describe as "H"-shaped or "I"-shaped, depending on which way you turn them around
  • and the DOWELS


The shape of the "H" or "I" bricks is designed so that they fit together to form a layer or a wall of bricks and importantly, the bricks, just by their very shape, immobilise each other from moving, in one dimension only.

Let's have a look at that.

Let's consider this green brick here as the fixed point.

We can see that it immobilises its neighbouring bricks in one dimension. They can't move with respect to the green brick in this dimension. So that's locked. Even though there is no bricks here or here, the very shape stops it moving in that dimension.

Now the shape doesn't stop the bricks moving with respect to each other in that direction, or in that direction but they are fixed in that one dimension.



Now if we want to make a rigid structure of bricks in all three dimensions but without using mortar or glue so that we can assemble and disassemble the structure whenever we like, what we need next are the DOWELS.

As you can see, the "I" or "H" bricks have shafts running through the corners so that you can run a dowel through the corners - two shafts, four holes per "I" or "H" brick.

And when you assemble the bricks you can slide the dowel in ... and this forms a structure which is rigid in all three dimensions, which is what we need to form structures.
« Last Edit: 14/01/2013 15:26:39 by Peter Dow »
 

The Naked Scientists Forum

HI-BRICKS & DOWELS demonstration video
« Reply #27 on: 14/01/2013 15:21:42 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums