When Kim Il-Jong recently visited Moscow on a surreal train journey, he proudly informed Vladimir Putin he was travelling in the armoured train given to his father as a present by Stalin.
H1 4 Favorites This Wood Species series of entries comes to us from guest writer Rob Wilkey, an Atlanta-based woodworker and industrial designer whose expertise is in small home goods, furniture, and large installations. Wood series, we'll start talking about the specific properties of different wood species, and the terminology used to discuss those properties.
Those of you who were paying attention during the previous MM: W entries will recognize some of the terms, but a little review never hurts. Overdifferent species of trees have been identified worldwide. Many are endangered, many are inaccessible, and many more aren't suitable for use as lumber.
In fact, only a very small portion of these species is harvested and dried for use, but that 'small portion' still comprises over species. Woods we see in everyday American life—pine, oak, and maple—make up a small and comparatively uninteresting group of species.
Introduction part of master thesis the globe, however, woods vary widely in appearance and physical properties.
Colors can range from pale yellows and grays to vibrant hues of purple, red, and green, and from rich browns to pure, solid black. For example, the South American species Lignum Vitae is so water-resistant and dense that it is commonly used in bearings for large naval craft and hydroelectric dams.
In order to fully understand these differences, and how they can affect your projects, I will cover some of the basic differentiating properties of wood and the terminology used to describe them. Janka hardness is a good place to start when selecting a wood species.
Janka is a measurement of the pounds of force required to embed a steel ball of a certain diameter into the surface of the wood.
This gives a very good indication of how easily the wood will dent and scratch. Woods below lbf on the Janka scale can be dented by pressing on them with your fingernail, and as such shouldn't be used on surfaces that will experience a lot of physical contact.
Conversely, woods above lbf Janka are so hard that they can blunt tools and become very difficult to work with. Janka hardness is also useful in that it often coincides with structural stability. Woods that have a higher Janka hardness tend to be better load-bearing woods than those lower on the hardness scale.
Grain type is another important factor to consider.
This tearout occurred when I was trying to plane down the edge of the board—the blade caught a section of grain that was interlocked with the surrounding wood, tearing out the entire area instead of cutting straight across as I had intended.
Certain factors, such as weighty branches and bulbous deformities called burls, can also affect the natural grain pattern, resulting in an effect called figured wood. The way that light refracts off of the surface of figured wood creates an almost holographic effect that can take the appearance of rolling waves and swirling pits, as seen in the images below.
Porosity affects both the appearance and working properties of the wood. Ring-porous woods have larger pores at the edge of their growth rings, while diffuse-porous woods have the same size of pores throughout. This can affect the appearance of the wood, especially in pieces that are flatsawn, as shown below.
Additionally, woods that are highly porous are harder to sand to a smooth finish, and tend to absorb more glue and finish than less porous woods. Shrinkage - the amount of dimensional change in a wood after it is dried - is also an important consideration, as it is often a good indicator of how much the wood will warp with changes to its environment - an effect called seasonal movement.Dramatic literature, the texts of plays that can be read, as distinct from being seen and heard in performance.
All plays depend upon a general agreement by all participants—author, actors, and audience—to accept the operation of theatre and the conventions associated with it, just as players.
Acknowledgements This master’s thesis has been done for a Finnish software testing consultancy com-pany Qentinel mainly during the year 1 1. Introduction The dissertation is the final stage of the Masters degree and provides you with the opportunity to show that you have gained the .
A thesis or dissertation is a document submitted in support of candidature for an academic degree or professional qualification presenting the author's research and findings.
In some contexts, the word "thesis" or a cognate is used for part of a bachelor's or master's course, while "dissertation" is normally applied to a doctorate, while in other contexts, the reverse is true. Density can vary from unbelievably light—balsa is less than 1/6th the density of water—to heavier than concrete.
For example, the South American species Lignum Vitae is so water-resistant and dense that it is commonly used in bearings for large naval craft and hydroelectric dams.
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Students prepare for careers in libraries, museums, and.