| Craig Chamberlain's Omni-Sphere domes provided an innovative solution and a new kind of transitional housing for the homeless. They provide an attractive alternative to the usual "brick and mortar" or institutional type buildings and one that is non-threatening to the local community. Omni-Spheres are 20' in diameter and 12 ' tall with an area of about 314 square feet inside. They are comprised of 21 panels and bolt easily together with 150 teflon bolts. The panels are made of a super strong polyester-fiberglass material which makes the domes extremely durable. The Omni-Sphere is water tight and maintenance free. They are quick to assemble and cam be put up in under four hours by a team of two with no more than a step ladder, a screwdriver and a wrench. There is also an insulated version called the Survival-Sphere which can hold the heat in sub-zero temperatures. The Dome Village is made up of 20 of these domes on a property of about one and one-third acres. Eight domes are community-use and include a kitchen, community room, office domes, separate women’s and men’s bath facilities, and a laundry dome. The remaining domes are residential, partitioned in half and providing private living space for two individuals or a family. The architectural structure of Dome Village is a powerful visual, drawing the attention of the general public and government, and focusing attention on the issue of homelessness in our community. Using the domes used as stabilizing tools helps to provide affordable transitional housing which is non-threatening to the chronic homeless person and to the neighborhood and also helps to achieve the goals of alleviating homelessness and reducing unsightly encampments in our city. A new generation of the dome structures has been created based on Craig Chamberlain's Omni-Sphere design. Versions are now available which is made of a new type of materials that have additional insulating and other qualities. For more information about the new dome structures please check out LEKShelters.com or InterShelter.com |
Sunday, February 7, 2016
Craig Chamberlain's Omni-Sphere domes
Sunday, January 3, 2016
Saturday, January 2, 2016
the math for making a sphere
Associated Topics || Dr. Math Home || Search Dr. Math
Making Hemispheres out of PaperDate: 07/28/99 at 16:23:08 From: Matt Osborn Subject: Making spheres from paper I'm a high school math teacher, and I've been trying to figure out how you would make a sphere from a piece of paper, for example, if I wanted my geometry students to be take a piece of paper and fold/cut it so that it would fit perfectly over the northern hemisphere of a globe. I first decided that I would focus on how to get a piece of paper to fold into a hemisphere. I think the best way would be to make the North Pole the center of the figure. I decided to use triangular wedges of 30 degrees. These triangular wedges are actually triangles I studied in non-Euclidean geometry because their angle measure is above 180 degrees, where the two congruent sides extending from the North Pole to the Equator are both perpendicular to the equator, but are 30 degrees apart in terms of longitudinal degrees. I can figure out the length of the base of this unique isosceles triangle, and I can also figure out the lengths of the congruent legs (since I can determine the radius). Where I have trouble is in how to convert this figure to a piece of paper. I know all three sides of this triangle are curved. I also know they are all parts of great circles. I don't know how to actually draw these curves or what the actual angle is for the vertex angle of this isosceles triangle. What type of curves are the sides? I know the vertex angle would be less than 30 degrees when drawn on a flat piece of paper, but I don't know what it would be in this case. Please help! What I have envisioned for the finished product (a pattern on a flat piece of paper that can be cut/folded so that it would become a hemisphere) of this figure would be similar to a flower, with the North Pole being the center of the flower, and each petal representing one of the non-Euclidean triangles. The empty spaces between these "petals" would be the unnecessary part of the hemisphere that would be folded under or cut off. Thanks for any help that you can give. Matt Date: 07/29/99 at 16:46:25
From: Doctor Rick
Subject: Re: Making spheres from paper
Hi, Matt.
I think you realize that any construction of cut and/or folded paper
will not fit perfectly over a sphere. The narrower you make your
wedges, the closer it will come, but you will never make a perfect
sphere. To be more specific, with 30-degree wedges, any cross-section
parallel to the equator will have the shape of a dodecagon rather than
a circle.
The method you describe, however, happens to be just what globe makers
do. They make pieces of map of this shape (which they call "gores")
and glue them on a sphere.
Now let's work out the shape of the gores. We'll make it so the center
line of each gore lies exactly on a sphere of radius r. Call the
angular width of each gore (the number of degrees of longitude it
covers) phi.
Look at an arbitrary cross-section of the globe parallel to the
equator. The plane of the cross-section meets the surface of the
sphere at latitude L. I will work with the co-latitude (angle measured
from the pole), in radians, which I will call theta.
theta = (90 - L) * pi/180
The radius of the circle that is the cross-section of the sphere is
r_c = r*sin(theta)
You can see this if you take another cross-section perpendicular to
this one, containing the axis of the sphere. There will be a right
triangle whose hypotenuse is r, one leg is r_c, and the opposite angle
is theta.
The cross-section of one gore is a line segment tangent to the circle
at its center. We want to find the width W of this line segment. Draw
a line from the center of the circle to the point of tangency, and
another from the center to the end of the tangent segment (the gore).
You get a right triangle with legs of length r and W/2; the angle
opposite W/2 is phi/2. Simple trigonometry gives us the width of the
gore as
W = 2*r_c*tan(phi/2)
= 2r*tan(phi/2)*sin(theta)
The distance (along the arc of the globe) from the point of the gore
to the line whose width we have just measured is r*theta. (Remember,
theta is measured in radians.) The full length of a gore, from tip to
tip, is pi*r. (The gore for a hemisphere will be half this, or
pi*r/2.) If you lay it out on graph paper so that the tip is at the
origin and the centerline is along the x-axis, then the two sides of
the gore will lie along the lines
y = +/- r*tan(phi/2)*sin(x/r)
So that's the shape of the sides of the "triangle." It's a sine curve
whose amplitude is determined by the angle phi.
As for the angle at the poles, it _will_ be exactly the angle phi.
However, the sides begin curving inward quickly, so we are talking
about the angle between the _tangents_ to two curved lines. The
equator end of the "spherical triangle" is a vertical line at
x = pi*r/2, and the sine curves are horizontal at x = pi*r/2 so the
angles are both right angles.
I haven't tried making one of these, so I don't know how easy or hard
it might be to assemble. I would try using a card stock rather than
thin paper so it's easier to handle; I would cut out the gores right
along their edges and tape them together on the inside of the
hemisphere. If that worked, I would think about fancier ways to do it.
Have fun!
- Doctor Rick, The Math Forum
http://mathforum.org/dr.math/
|
High School Geometry
High School Higher-Dimensional Geometry
Inflatable Boat Tube Fabric Guide
Inflatable Boat Tube Fabric Guide
Inflatable Boat Tube Fabrics
Hypalon and Neoprene Coatings (Synthetic Rubber Coatings):
Hypalon is a synthetic rubber material patented by DuPont. Hypalon has many applications in many industries and it has proven itself as a material with excellent air holding capabilities and oil resistance. Hypalon coated onto polyester or nylon fabric with an interior coating of neoprene a very reliable and durable inflatable boat fabric and can last for more than a decade even in the harshest environments – which is the reason for warranties of five and 10 years.
Hypalon and Neoprene Coatings (Synthetic Rubber Coatings):
Hypalon is a synthetic rubber material patented by DuPont. Hypalon has many applications in many industries and it has proven itself as a material with excellent air holding capabilities and oil resistance. Hypalon coated onto polyester or nylon fabric with an interior coating of neoprene a very reliable and durable inflatable boat fabric and can last for more than a decade even in the harshest environments – which is the reason for warranties of five and 10 years.
Hypalon Construction:
The seams in Hypalon boats are either overlapped or butted, and then glued. Butted seams produce an aesthetic, flat, airtight seam, without the ridge or air gaps left by some overlapped seams. However, butted seams are more labor-intensive, thus the boats are usually more expensive. It is always wise to look for an inflatable boat with seams that are double-taped, and are glued on both sides. In stress tests, Hypalon and neoprene glued seams are so strong and reliable that the fabric will fail before the seams.
PVC (Plastic Coatings):
PVC is a vinyl polymer chemically known as polyvinyl chloride. It has several applications in the leisure and construction industries. In the inflatable boat industry it is used as a coating on polyester or nylon to increase the strength and tear resistance. Because it is a type of plastic, it can be thermobonded or glued. This allows the manufacturer to mass produce boats on a large scale with machines and unskilled labour. PVC coated fabrics come in a larger array of colours than Hypalon
PVC is a vinyl polymer chemically known as polyvinyl chloride. It has several applications in the leisure and construction industries. In the inflatable boat industry it is used as a coating on polyester or nylon to increase the strength and tear resistance. Because it is a type of plastic, it can be thermobonded or glued. This allows the manufacturer to mass produce boats on a large scale with machines and unskilled labour. PVC coated fabrics come in a larger array of colours than Hypalon
PVC Construction:The seams of PVC-coated inflatables can be fused together using several different welding techniques. Some manufacturers use either high heat pressure, radio frequencies (RF), or electronic welding. Large, specially developed welding machines must be used to fuse the fabric together. Again, this makes it easier and faster to produce PVC-coated boats, especially over handcrafted Hypalon boats.
Friday, January 1, 2016
do it your self shell
http://domesheltersystem.s3.amazonaws.com/index.html
http://www.weasel.com/dome_cover.html
http://www.flyingconcrete.com/lloyd-turner.htm he did work for monolithic domes before they sent hi to the shitter
A parachute covered 32 foot, 4 frequency dome. Note the parachute stretching and how it catches the wind.
Tyvek (made by DuPont): The material of those silky non-woven strong envelope. Made from high density polyethylene fibers. Very reasonably priced from home construction stores. Look for 'Tyvek Home Wrap'. It comes in rolls 9 feet by 150 feet. It costs roughly $50 a roll. It is reasonably waterproof, dustproof, and windproof. It is white, which minimizes heating in the sun. It is reasonably easy to work with. It is pretty strong. If you want a piece bigger than 9 feet wide, you will have to build it from smaller pieces. You can get Tyvek Tape, which is made of Tyvek and has adhesive designed to stick to Tyvek.
Tyvek ThermaWrap (made by DuPont): Same as Tyvek, but metalized. Dupont even has Tyvek Metalized Tape to connect the edges of Tyvek ThermaWrap. I think this is likely the best, coolest, reasonable cost material to cover a dome. If I would have know about this, I would have bought a roll of it. It comes in rolls 9 feet by 100 feet, or 5 feet by 150 feet.
Aluminumized Mylar: Space blanket material. I saw a dome covered with this. No idea where to buy big pieces of it. Probably the ideal material to keep a dome cool. It is very fragile stuff, and rips if you look at it the wrong way. The only practical way I can think of to use this is to have it glued to rigid board insulation, like the Hexaurt construction.
Shelter systems Fabrics: Shelter systems has several woven ripstop films. There is the Translucent Greenhouse Covering, which lets in 90% of light through, their White covering which lets 60% of light through, and Clear Vinyl. The first two are $10 a yard (6 foot wide roll), and the Clear Vinyl is $20 a yard (4 foot wide roll). This stuff is very strong and water and dust proof. Heavier duty than tyvek, and a lot more expensive.
Shadecloth: Made of some synthetic material and designed to make partial shading. Won't stop wind, rain, or dust. Good for doors for privacy, or for ventilation.
Trucker Tarp: Made of 14x14 mesh of 1000 denier nylon threads. 11 mil thick. Grommets at corners and every 3 feet along edge. Reasonably priced. Very heavy duty. Waterproof, dustproof, doesn't stretch, very abrasion resistant. Lets some light through. This is the most abrasion resistant fabric listed. This is also the strongest fabric listed. For high winds, I think it is the best material, due to its superior strength. It also can be bought in large pieces so it is not necessary to put small pieces together to make a bigger piece. The color isn't great to reflect sunlight, but it works reasonably well.
Aluminet: Made by Polysack. Blocks up to 70% of UV. It is an ^1aluminized knit fabric. Not windproof, waterproof, or dustproof. Can be bought in widths up to 28 feet. You can buy it at Gothic Arch Greenhouses. It costs between $0.24 a square foot (for the 30% shade) to $0.31 a square foot (for the 70% shade). Likely will keep a dome reasonably cool, though you will need an inner cover as well to keep the dust, wind, and water out.
Silvicool Tarps: Made by Bushpro Supplies Inc.. A highly reflective tarp. Supposed to last for years. Has loops sewn into the corners and along the edges. Stock sizes up to 18 by 24 feet. Can be made in custom sizes. Looks to be dustproof, waterproof, and windproof. If I was building another cover, I would call these folks up and find out more about this.
Reflectix50: Highly reflective 7 layer thick insulation, 5/16 inches thick. Aluminum color on both sides, bubble wrap in the center. You can buy it at Atlanta Supply Co.. A 50 foot by 4 foot roll costs $61. Likely waterproof, dustproof, and windproof. Not as strong as fabric or tarp
http://www.weasel.com/dome_cover.html
http://www.flyingconcrete.com/lloyd-turner.htm he did work for monolithic domes before they sent hi to the shitter
Monolithic designs, manufactures and markets a prime ingredient used in the construction of Monolithic Domes, Crenospheres and EcoShells: the Airform. It’s an inflatable structure, made of PVC-coated nylon or polyester fabric, that determines the shape and size of a dome.
Our other specialty fabric structures include compost covers, grain covers, condensate ceilings, methane tank liners, water tank diaphragms and tension tarps.
We al
A parachute covered 32 foot, 4 frequency dome. Note the parachute stretching and how it catches the wind.
Tyvek (made by DuPont): The material of those silky non-woven strong envelope. Made from high density polyethylene fibers. Very reasonably priced from home construction stores. Look for 'Tyvek Home Wrap'. It comes in rolls 9 feet by 150 feet. It costs roughly $50 a roll. It is reasonably waterproof, dustproof, and windproof. It is white, which minimizes heating in the sun. It is reasonably easy to work with. It is pretty strong. If you want a piece bigger than 9 feet wide, you will have to build it from smaller pieces. You can get Tyvek Tape, which is made of Tyvek and has adhesive designed to stick to Tyvek.
Tyvek ThermaWrap (made by DuPont): Same as Tyvek, but metalized. Dupont even has Tyvek Metalized Tape to connect the edges of Tyvek ThermaWrap. I think this is likely the best, coolest, reasonable cost material to cover a dome. If I would have know about this, I would have bought a roll of it. It comes in rolls 9 feet by 100 feet, or 5 feet by 150 feet.
Aluminumized Mylar: Space blanket material. I saw a dome covered with this. No idea where to buy big pieces of it. Probably the ideal material to keep a dome cool. It is very fragile stuff, and rips if you look at it the wrong way. The only practical way I can think of to use this is to have it glued to rigid board insulation, like the Hexaurt construction.
Shelter systems Fabrics: Shelter systems has several woven ripstop films. There is the Translucent Greenhouse Covering, which lets in 90% of light through, their White covering which lets 60% of light through, and Clear Vinyl. The first two are $10 a yard (6 foot wide roll), and the Clear Vinyl is $20 a yard (4 foot wide roll). This stuff is very strong and water and dust proof. Heavier duty than tyvek, and a lot more expensive.
Shadecloth: Made of some synthetic material and designed to make partial shading. Won't stop wind, rain, or dust. Good for doors for privacy, or for ventilation.
Trucker Tarp: Made of 14x14 mesh of 1000 denier nylon threads. 11 mil thick. Grommets at corners and every 3 feet along edge. Reasonably priced. Very heavy duty. Waterproof, dustproof, doesn't stretch, very abrasion resistant. Lets some light through. This is the most abrasion resistant fabric listed. This is also the strongest fabric listed. For high winds, I think it is the best material, due to its superior strength. It also can be bought in large pieces so it is not necessary to put small pieces together to make a bigger piece. The color isn't great to reflect sunlight, but it works reasonably well.
Aluminet: Made by Polysack. Blocks up to 70% of UV. It is an ^1aluminized knit fabric. Not windproof, waterproof, or dustproof. Can be bought in widths up to 28 feet. You can buy it at Gothic Arch Greenhouses. It costs between $0.24 a square foot (for the 30% shade) to $0.31 a square foot (for the 70% shade). Likely will keep a dome reasonably cool, though you will need an inner cover as well to keep the dust, wind, and water out.
Silvicool Tarps: Made by Bushpro Supplies Inc.. A highly reflective tarp. Supposed to last for years. Has loops sewn into the corners and along the edges. Stock sizes up to 18 by 24 feet. Can be made in custom sizes. Looks to be dustproof, waterproof, and windproof. If I was building another cover, I would call these folks up and find out more about this.
Reflectix50: Highly reflective 7 layer thick insulation, 5/16 inches thick. Aluminum color on both sides, bubble wrap in the center. You can buy it at Atlanta Supply Co.. A 50 foot by 4 foot roll costs $61. Likely waterproof, dustproof, and windproof. Not as strong as fabric or tarp
1
|
I had to construct hemisphere in MATLAB ,so I did this:
The code was not written by me so I want to understand this,when I replace ' in
phi = (pi/2)*(0:2:n)'/n;I get following error : operator *: nonconformant arguments (op1 is 1x16, op2 is 1x32)
Please explain why is it essential....
Also,I wanted to write an easier code for sketching hemisphere.any idea for some shorter command/method I can use in matlab.... |
Material for Inflatable
Inflatable products use all kinds of
fabrics. No matter what kind of fabrics they are, they have the
following characteristics: durable enough for specific inflatable and
general/specific usage, appropriate melting point for air-tight products,
and good air-tight characters to hold pressure inside, etc.
Generally, inflatable fabrics are all PVC
material or PVC/PU coated nylon material. Its thickness starts from
0.18MM to 1.00MM or thicker. But most of fabric will fall within this
range. For example, most air-tight inflatable toys are made of 0.18MM or
0.24MM PVC, while inflatable bouncers and jumping houses use 0.50-0.60MM PVC/PU
coated material.
If it is non-airtight inflatable, then the
fabric has more choices, from nylon fabric to mesh reinforced, PVC or PU coated
fabric. Non air-tight can also use a mixture of several kind of fabrics
to make colorful inflatables.
Beside fabrics, air blower is another part
of whole complete set. Air blower can be gas-powered or
electric-powered. The power of air blower depends on the size of
inflatable. Generally, the bigger the inflatable is, the more power air
blower is needed to blow it up and keep it shape. Also air blower can be
internal or external. Some small inflatable may come with internal air
blower, so you just need to plug and play and get the inflatable set up in
couple of minutes
We take the
quality of our materials, our construction methods, and the finished end
product very seriously. Please do not hesitate to contact us to discuss our
products, materials and how we construct giant inflatables.
There
are subtle and extreme differences in helium parade balloon materials used in
the industry. The majority of inflatable balloon companies do not manufacture
their own helium balloons. Instead, they job them out to companies overseas,
especially helium products. There are only a hand full of companies in the
World that construct premium helium parade balloons or Airtight Inflatables and
Big Ideas Parade Giants is one of them.
The materials we use are tested by us for
strength, sealability, coating adhesion, and hot and cold exposure and how it
relates to performance and longevity of the end product. We have many fabrics
we use and many varied fabrics that we test. Some of the
fabrics we use are formulated (coatings) to our specifications and custom
milled for us. We can have custom fabrics milled to meet your specifications
too.
Our warranty reflects the quality of the
urethane fabrics we use and our proprietary construction methods. Included with
most of the helium retention and airtight products we produce is a 12 month
warranty that covers workmanship and materials on all our our custom helium
parade and inflatable helium balloon creations, however, you can expect many
years of use! We also
provide custom instructions for each custom helium parade balloon we
manufacture. Professional installation or training at your event is also
available for larger inflatable systems.
1. UV
Treated – for protection from the sun’s UV rays.
2.
Mildew Resistant – protection from moisture / water.
3. Fire
Retardant – fire rated and resistant.
Fabrics with these characteristics are the
best choice because they provide the best protection during use, and add to the
longevity of the product. These fabrics also provide ease of cleaning of the
product so it’s always looking it’s best. When it comes to
putting the shapes together, we use industrial sewing machines and commercial
sewing techniques to ensure strength and durability of the finished product.
Anything without these characteristics and manufacturing methods is an
inferior, cheaper product usually manufactured in China or India that will lead
in fact to early potential product failure and short product life. In most cases our Warranty covers product workmanship and
materials for a period of 24 months, however, expect many years of use from our
products
I'm starting this topic to both log my experiments and to petition
contributions and ideas from others.
The basic premise, to build a strong, inexpensive inflatable boat. If you look at the Zodiacs, you'll see they run into the thousands of dollars. Even the lower cost (smaller) inflatables at WestMarine sell for over a thousand and go up. My basic plan is to use some heavy canvas, and impregnate it with something to make it air tight. The canvas should add plenty of strength allowing it to hold a little bit of pressure and stay rigid. Everyone I've spoken to about this project has responded either that I'm crazy (possible), this is impossible (I'll never believe it), or both.
Lets start with the base material. I am really thinking of using a heavy canvas, like the kind available at the hardware store as painter's drop cloth. Purchased like that, I can get large pieces of canvas that are very sturdy and inexpensive. I've used this material to make bags, covers, and cushoins for my sail boat. So, I think its a good starting point.
Next up, a low cost way to make the canvas air tight and durable. An early thought was to use latex because its cheap and readily available. The problem is latex will not last very long exposed to the sun and elements. I have experimented with "PlastiDip" stuff used to plastic coat tools, and "liquid electrical tape" but, these two substances are hard to the saturate fabric with. Probably just as well, as these would be pretty expensive in the quantity required.
The basic premise, to build a strong, inexpensive inflatable boat. If you look at the Zodiacs, you'll see they run into the thousands of dollars. Even the lower cost (smaller) inflatables at WestMarine sell for over a thousand and go up. My basic plan is to use some heavy canvas, and impregnate it with something to make it air tight. The canvas should add plenty of strength allowing it to hold a little bit of pressure and stay rigid. Everyone I've spoken to about this project has responded either that I'm crazy (possible), this is impossible (I'll never believe it), or both.
Lets start with the base material. I am really thinking of using a heavy canvas, like the kind available at the hardware store as painter's drop cloth. Purchased like that, I can get large pieces of canvas that are very sturdy and inexpensive. I've used this material to make bags, covers, and cushoins for my sail boat. So, I think its a good starting point.
Next up, a low cost way to make the canvas air tight and durable. An early thought was to use latex because its cheap and readily available. The problem is latex will not last very long exposed to the sun and elements. I have experimented with "PlastiDip" stuff used to plastic coat tools, and "liquid electrical tape" but, these two substances are hard to the saturate fabric with. Probably just as well, as these would be pretty expensive in the quantity required.
Step 1: Trival Math
This is trivial but, still
something to consider.
The greater the airpressure in the inflated chambers, the stiffer the vessel will be. Determining the air pressure to use will come from a combination of material strength and size of the chamber. This will be modified downward with a consideration of material strength decline with age, consideration of forces from use (people sitting on it, waves, motor, etc) and a safety fudge factor.
Generally in the realm of inflatable boats, 5psi is considered high pressure.
So, for a 24 inch diameter tube, we get a circumference rounded up to 76 inches. So, 1 psi would equate to 76 pounds of force trying to tear it apart (2 would be 152). Since large tubes will be very hard to contain lots of pressure, a compromise could be to stack narrower tubes that could each have a higher pressure.
This asks for some pro/con cosideration.
Stacked Tubes:
The greater the airpressure in the inflated chambers, the stiffer the vessel will be. Determining the air pressure to use will come from a combination of material strength and size of the chamber. This will be modified downward with a consideration of material strength decline with age, consideration of forces from use (people sitting on it, waves, motor, etc) and a safety fudge factor.
Generally in the realm of inflatable boats, 5psi is considered high pressure.
So, for a 24 inch diameter tube, we get a circumference rounded up to 76 inches. So, 1 psi would equate to 76 pounds of force trying to tear it apart (2 would be 152). Since large tubes will be very hard to contain lots of pressure, a compromise could be to stack narrower tubes that could each have a higher pressure.
This asks for some pro/con cosideration.
Stacked Tubes:
PRO | CON• Higher pressuere (stiffer) | • Greater
weight• More air chambers safer if | • More complex construction there is a puncture | • More material/expense
The single tube is basically, the opposite of the
above. If material costs are kept low, the cost part may not be a big deal.
A quick and dirty method of measuring the strength of the material is to cut a one inch wide strip to a length equal to the desired circumference, plus a little bit for hangers. Hang it up and start suspending weights from it until it breaks. Do it a few times and pick the low value for the weight that causes it to break.
A quick and dirty method of measuring the strength of the material is to cut a one inch wide strip to a length equal to the desired circumference, plus a little bit for hangers. Hang it up and start suspending weights from it until it breaks. Do it a few times and pick the low value for the weight that causes it to break.
Inflatable Boat Tube Fabric Guide
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