Composite material in the context of Pit (nuclear weapon)

Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. Being a natural material, it is characterized as an organic material – a natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin and hemicelluloses that resists compression.

Wood is sometimes defined as only the secondary xylem in the stems of trees, or 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 mechanical-support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients among the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, woodchips, or fibers.

Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactured material in the world.

When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that can be poured and molded into shape. The cement reacts with the water through a process called hydration, which hardens it after several hours to form a solid matrix that binds the materials together into a durable stone-like material with various uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process is exothermic, which means that ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers) are included in the mixture to improve the physical properties of the wet mix, delay or accelerate the curing time, or otherwise modify the finished material. Most structural concrete is poured with reinforcing materials (such as steel rebar) embedded to provide tensile strength, yielding reinforced concrete.

Papier-mâché (UK: /ˌpæpieɪ ˈmæʃeɪ/ PAP-ee-ay MASH-ay, US: /ˌpeɪpər məˈʃeɪ/ PAY-pər mə-SHAY, French: [papje mɑʃe] – the French term "mâché" here means "crushed and ground") is a versatile craft technique with roots in ancient China, in which waste paper is shredded and mixed with water and a binder to produce a pulp ideal for modelling or moulding, which dries to a hard surface and allows the creation of light, strong and inexpensive objects of any shape, even very complicated ones. There are various recipes, including those using cardboard and some mineral elements such as chalk or clay (carton-pierre, a building material). Papier-mâché reinforced with textiles or boiled cardboard (carton bouilli) can be used for durable, sturdy objects. There is even carton-cuir (cardboard and leather) and also a "laminating process", a method in which strips of paper are glued together in layers. Binding agents include glue, starch or wallpaper paste. "Carton-paille" or strawboard was already described in a book in 1881. Pasteboard is made of whole sheets of paper glued together, or layers of paper pulp pressed together. Millboard is a type of strong pasteboard that contains old rope and other coarse materials in addition to paper.

This composite material can be used in a variety of traditional and ceremonial activities, as well as in arts and crafts, for example to make many different inexpensive items such as Christmas decorations (including nativity figures), toys or masks, or models for educational purposes, or even pieces of furniture, and is ideal for large-scale production; Carton-pierre can be used to make decorative architectural elements, sculptures and statues, or theatre or film sets; papier-mâché has also been used to make household objects, which can become valuable if artistically painted (as many boxes and snuffboxes were in the past) or lacquered, sometimes with inlays of mother-of-pearl, for example. Large papier-mâché pieces, such as statues or carnival floats, require a wooden (or bamboo, etc.) frame. Making papier-mâché is also a popular pastime, especially with children.

In materials science, a refractory (or refractory material) is a material that is resistant to decomposition by heat or chemical attack and that retains its strength and rigidity at high temperatures. They are inorganic, non-metallic compounds that may be porous or non-porous, and their crystallinity varies widely: they may be crystalline, polycrystalline, amorphous, or composite. They are typically composed of oxides, carbides or nitrides of the following elements: silicon, aluminium, magnesium, calcium, boron, chromium and zirconium. Many refractories are ceramics, but some such as graphite are not, and some ceramics such as clay pottery are not considered refractory. Refractories are distinguished from the refractory metals, which are elemental metals and their alloys that have high melting temperatures.

Refractories are defined by ASTM C71 as "non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1,000 °F (811 K; 538 °C)". Refractory materials are used in furnaces, kilns, incinerators, and reactors. Refractories are also used to make crucibles and molds for casting glass and metals. The iron and steel industry and metal casting sectors use approximately 70% of all refractories produced.

Natural fibers or natural fibres (see spelling differences) are fibers that are produced by geological processes, or from the bodies of plants or animals. They can be used as a component of composite materials, where the orientation of fibers impacts the properties. Natural fibers can also be matted into sheets to make paper or felt.

The earliest evidence of humans using fibers is the discovery of wool and dyed flax fibers found in a prehistoric cave in the Republic of Georgia that date back to 36,000 BP. Natural fibers can be used for high-tech applications, such as composite parts for automobiles and medical supplies. Compared to composites reinforced with glass fibers, composites with natural fibers have advantages such as lower density, better thermal insulation, and reduced skin irritation. Further, unlike glass fibers, natural fibers can be broken down by bacteria once they are no longer used.

• A ″ natural material a substance that comes from plants, animals, or the earth, and has not been made by humans.. Minerals and the metals that can be extracted from them (without further modification) are also considered to belong into this category. Natural materials are used as building materials and clothing. Types include:

• Biotic materials
  • Wood (rattan, bamboo, bark, etc.)
• Plant fiber (coir, ramie, sisal, cotton, flax, hemp, jute, kapok, kenaf, moss, linen, abacá, etc.)
• Animal fiber (wool, silk, alpaca, camel, angora, cashmere, mohair, etc.)
• Inorganic material
  • Stone (flint, granite, limestone, obsidian, sandstone, sand, gems, glass, etc.)
  • Native metal (copper, iron, gold, silver, etc.)
  • Composites (clay, plasticine, etc.)
• Other natural materials.
  • Soil

Construction aggregate, or simply aggregate, is a broad category of coarse to medium-grained particulate material used in construction. Traditionally, it includes natural materials such as sand, gravel, and crushed stone. As with other types of aggregates, it is a component of composite materials, particularly concrete and asphalt.Aggregates are the most mined materials in the world, being a significant part of the 6 billion tons of concrete produced per year.

Aggregate serves as reinforcement to add strength to the resulting material. Due to the relatively high hydraulic conductivity as compared to most soil types, aggregates are widely used in drainage applications such as foundation and French drains, septic drain fields, retaining wall drains, and roadside edge drains. Aggregates are also used as base material under building foundations, roads and railroads (aggregate base). It has predictable, uniform properties, preventing differential settling under the road or building.

Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel reinforcing bars (known as rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion.

Microstructure is the very small-scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material (e.g. metals, polymers, ceramics, or composites) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice.

Microstructure at scales smaller than can be viewed with optical microscopes is often called nanostructure, while the structure in which individual atoms are arranged is known as crystal structure. The nanostructure of biological specimens is referred to as ultrastructure.

Machining is a manufacturing process where a desired shape or part is created using the controlled removal of material, most often metal, from a larger piece of raw material by cutting. Machining is a form of subtractive manufacturing, which utilizes machine tools, in contrast to additive manufacturing (e.g. 3D printing), which uses controlled addition of material.

Machining is a major process of the manufacture of many metal products, but it can also be used on other materials such as wood, plastic, ceramic, and composites. A person who specializes in machining is called a machinist. As a commercial venture, machining is generally performed in a machine shop, which consists of one or more workrooms containing primary machine tools. Although a machine shop can be a standalone operation, many businesses maintain internal machine shops or tool rooms that support their specialized needs. Much modern-day machining uses computer numerical control (CNC), in which computers control the movement and operation of mills, lathes, and other cutting machines.

Nacre (/ˈneɪkər/ NAY-kər, also /ˈnækrə/ NAK-rə), also known as mother-of-pearl, is an organic–inorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent.

Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as flame structure as is found in conch pearls.

Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac, bitmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams. Asphalt mixtures have been used in pavement construction since the nineteenth century. It consists of mineral aggregate bound together with bitumen (a substance also independently known as asphalt, pitch, or tar), laid in layers, and compacted.

The American English terms asphalt (or asphaltic) concrete, bituminous asphalt concrete, and bituminous mixture are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation, AC, is sometimes used for asphalt concrete but can also denote asphalt content or asphalt cement, referring to the liquid asphalt portion of the composite material.

Filler materials are particles added to binders (resin, thermoplastics, cement) to make a composite material. Filler materials improve specific properties or make the product cheaper.

Coarse filler materials such as construction aggregate and rebar are used in the building industry to make plaster, mortar and concrete.

A void or a pore is three-dimensional region that remains unfilled with polymer and fibers in a composite material. Voids are typically the result of poor manufacturing of the material and are generally deemed undesirable. Voids can affect the mechanical properties and lifespan of the composite. They degrade mainly the matrix-dominated properties such as interlaminar shear strength, longitudinal compressive strength, and transverse tensile strength. Voids can act as crack initiation sites as well as allow moisture to penetrate the composite and contribute to the anisotropy of the composite. For aerospace applications, a void content of approximately 1% is still acceptable, while for less sensitive applications, the allowance limit is 3-5%. Although a small increase in void content may not seem to cause significant issues, a 1-3% increase in void content of carbon fiber reinforced composite can reduce the mechanical properties by up to 20%

A toy soldier is a miniature figurine that represents a soldier. The term applies to depictions of uniformed military personnel from all eras, and includes knights, cowboys, American Indians, pirates, samurai, and other subjects that involve combat-related themes. Toy soldiers vary from simple playthings to highly realistic and detailed models. The latter are of more recent development and are sometimes called model figures to distinguish them from traditional toy soldiers. Larger scale toys such as dolls and action figures may come in military uniforms, but they are not generally considered toy soldiers.

Toy soldiers are made from all types of material, but the most common mass-produced varieties are metal and plastic. There are many different kinds of toy soldiers, including tin soldiers or flats, hollow-cast metal figures, composition figures, and plastic army men. Metal toy soldiers were traditionally sold in sets; plastic figures were sold in toy shops individually in Britain and Europe and in large boxed sets in the U.S. Modern, collectable figures are often sold individually.

Polymer chemistry is a sub-discipline of chemistry that focuses on the structures, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules. However, polymer chemistry is typically related to synthetic and organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, such as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.