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Materials Engineer |
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| Bibliography: http://www.piag.org/buyer/tips/Paper_grades.htm - Paper grades and weights http://www.straightdope.com/mailbag/mglue.html -How glue works http://en.wikipedia.org/wiki/File_folder - File folders http://www.tappi.org/paperu/all_about_paper/paperMade.htm http://john.hultgren.org/trivia/glue.html - How glue works
Team Determination! |
It's all About the Paper!
There are five basic groups of paper
grades. The first one is bond paper. Bond paper is usually used for
letterheads (stationary), quick copy/printing jobs, and most
business forms. Next is offset or uncoated book paper, this paper is
used mainly for sheet or offset printing which gives the final
project a smooth look. Also there is coated book paper which is a
very glossy sheet that provides outstanding colors and great
reproduction. Then there is text paper. Text paper provides soft
colors with a look of high class, especially because of its high
quality and texture. Lastly, there is cover paper, which usually
used for postcards or book covers. Within each grade of paper there
are other differences that set them apart from each other, such as
fiber content, brightness, and dullness.
Now it’s time to know the weight of the five basic groups of paper. The first paper was bond paper. This type of paper weights about 20# for printing, 24# for letterheads, and 16# for forms. (When there is # after a number it means pounds per 500 sheets, for example 20# stands for 20 lbs. for every 500 sheets of that paper.) Next we have the offset paper which ranges from 50# to 70#. Then there is coated book paper which is anywhere from 30# to 70#. Text paper weights fall between 60# and 100#. Finally there’s cover paper that can weigh 60#, 65#, 80#, or 100#. But, the paper we are working with are file folders and are usually made from paper pulp with long cellulose fiber, such as manila paper and Kraft paper. (strong, relatively coarse paper)
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Reflections: Our design was a great success because of the effort and thought we put into it. the structure met the height requirement for the project and succeeded in the weight requirements. our project was 11and 3/4 inches tall and held 405 pounds. I feel our design was great because it was very sturdy and was basically solid due to all of the glue we used. Our structure project was fairly wide, so I believed that helped in distributing the weight evenly causing less pressure to be in one area. Also, we used different 3-D shapes, so if one was stronger than the other we would have the support we needed. Although our structure was strong, it could have been stronger if we doubled up the file folders or even used the same amount of glue on each side. This way each side of the project could hold it's own weight. If I had the chance to redo the project, I probably would have used more triangles rather than cylinders because I feel triangles can hold more weight. I might have even gone in a completely different structure and tried to build the tallest structure, so we could get extra points for that.
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What was it made of?! Our whole structure was made of file folders and white glue. The file folders we used are made from paper pulp with long cellulose fiber, such as manila paper and kraft paper (strong, relatively coarse paper). The white glue we used to hold the file folders together was made of mainly water and polyvinyl-acetate latex (a non-toxic substance). This white glue works through evaporation because when the water evaporates it leaves the polyvinyl-acetate latex which creates a flexible bond. The glue usually takes 20 to 30 minutes to dry, but for the glue’s bond to reach its full strength, it takes 24-hours. Also, the glue dries faster when applied to wood because the wood helps to absorb some of the water. Once it was all dried it was strong and ready to be tested!
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Adhesion... Cohesion... What's the difference? Well, first of all adhesion is the capability to stick to the surface where it is applied such as sticking a magnet to a refrigerator. But cohesion is the capability to stick to itself such as gum or tape. This means that adhesion can’t stick to itself like cohesion can. |
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Can we get stronger paper? Unfortunately, all the paper we had to work with was 10 file folders. As you may know file folder paper is strong, but it would be better if we had stronger paper. What you may not know, is that you can make paper stronger by choosing what kind of wood your paper is made out of. There are two different types of wood, hardwood and softwood. Hardwood comes from oak and maple trees, which has short fibers making it weaker, but easier to write on. Softwood, on the other hand, comes from pine and spruce trees, which has long fibers making it stronger. Therefore when making strong paper you need to make it from softwood trees. |
This sure is fun!
Let's get down to business! |
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I need answers! During this project we had to interview either an engineer or an architect. I interviewed an architect. Person interviewed: Russell Francois The Questions 1. What is the best structural design for the
base of a building?
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The Answers 1. The design depends on the soil's bearing
capacity and should take into account the efficient use of materials |
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