Impulse excitation techniqueThe impulse excitation technique (IET) is a non-destructive material characterization technique to determine the elastic properties and internal friction of a material of interest. It measures the resonant frequencies in order to calculate the Young's modulus, shear modulus, Poisson's ratio and internal friction of predefined shapes like rectangular bars, cylindrical rods and disc shaped samples. The measurements can be performed at room temperature or at elevated temperatures (up to 1700 °C) under different atmospheres.
Abies balsameaAbies balsamea or balsam fir is a North American fir, native to most of eastern and central Canada (Newfoundland west to central Alberta) and the northeastern United States (Minnesota east to Maine, and south in the Appalachian Mountains to West Virginia). Balsam fir is a small to medium-size evergreen tree typically tall, occasionally reaching a height of . The narrow conic crown consists of dense, dark-green leaves. The bark on young trees is smooth, grey, and with resin blisters (which tend to spray when ruptured), becoming rough and fissured or scaly on old trees.
Bulk modulusThe bulk modulus ( or ) of a substance is a measure of the resistance of a substance to bulk compression. It is defined as the ratio of the infinitesimal pressure increase to the resulting relative decrease of the volume. Other moduli describe the material's response (strain) to other kinds of stress: the shear modulus describes the response to shear stress, and Young's modulus describes the response to normal (lengthwise stretching) stress. For a fluid, only the bulk modulus is meaningful.
Fraser firThe Fraser fir (Abies fraseri) is an endangered species of fir native to the Appalachian Mountains of the Southeastern United States. Abies fraseri is closely related to Abies balsamea (balsam fir), of which it has occasionally been treated as a subspecies (as A. balsamea subsp. fraseri (Pursh) E.Murray) or a variety (as A. balsamea var. fraseri (Pursh) Spach). Some botanists regard the variety of balsam fir named Abies balsamea var. phanerolepis as a natural hybrid with Fraser fir, denominated Abies × phanerolepis (Fernald) Liu.
Specific strengthThe specific strength is a material's (or muscle's) strength (force per unit area at failure) divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio. In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit for specific strength is Pa⋅m3/kg, or N⋅m/kg, which is dimensionally equivalent to m2/s2, though the latter form is rarely used.
Wood industryThe wood industry or timber industry (sometimes lumber industry -- when referring mainly to sawed boards) is the industry concerned with forestry, logging, timber trade, and the production of primary forest products and wood products (e.g. furniture) and secondary products like wood pulp for the pulp and paper industry. Some of the largest producers are also among the biggest owners of timberland. The wood industry has historically been and continues to be an important sector in many economies.
Christmas treeA Christmas tree is a decorated tree, usually an evergreen conifer, such as a spruce, pine or fir, or an artificial tree of similar appearance, associated with the celebration of Christmas. The tree was traditionally decorated with "roses made of colored paper, apples, wafers, tinsel, [and] sweetmeats". Moravian Christians began to illuminate Christmas trees with candles, which were often replaced by Christmas lights after the advent of electrification.
Pinus sylvestrisPinus sylvestris, the Scots pine (UK), Scotch pine (US) or Baltic pine, is a species of tree in the pine family Pinaceae that is native to Eurasia. It can readily be identified by its combination of fairly short, blue-green leaves and orange-red bark. Pinus sylvestris is an evergreen coniferous tree growing up to in height and in trunk diameter when mature, exceptionally over tall and in trunk diameter on very productive sites. The tallest on record is a tree over 210 years old growing in Estonia which stands at .
Timber framingTimber framing (Holzfachwerk) and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden pegs. If the structural frame of load-bearing timber is left exposed on the exterior of the building it may be referred to as half-timbered, and in many cases the infill between timbers will be used for decorative effect.
WoodWood is a structural tissue found in the stems and roots of trees and other woody plants. It is an organic material - a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves.
