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.
Glass ionomer cementA glass ionomer cement (GIC) is a dental restorative material used in dentistry as a filling material and luting cement, including for orthodontic bracket attachment. Glass-ionomer cements are based on the reaction of silicate glass-powder (calciumaluminofluorosilicate glass) and polyacrylic acid, an ionomer. Occasionally water is used instead of an acid, altering the properties of the material and its uses. This reaction produces a powdered cement of glass particles surrounded by matrix of fluoride elements and is known chemically as glass polyalkenoate.
Pressure solutionIn structural geology and diagenesis, pressure solution or pressure dissolution is a deformation mechanism that involves the dissolution of minerals at grain-to-grain contacts into an aqueous pore fluid in areas of relatively high stress and either deposition in regions of relatively low stress within the same rock or their complete removal from the rock within the fluid. It is an example of diffusive mass transfer. The detailed kinetics of the process was reviewed by Rutter (1976), and since then such kinetics has been used in many applications in earth sciences.
FlintFlint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey or black, green, white, or brown in colour, and has a glassy or waxy appearance.
ThermiteThermite ('θɜːrmaɪt) is a pyrotechnic composition of metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic reduction-oxidation (redox) reaction. Most varieties are not explosive, but can create brief bursts of heat and high temperature in a small area. Its form of action is similar to that of other fuel-oxidizer mixtures, such as black powder. Thermites have diverse compositions. Fuels include aluminium, magnesium, titanium, zinc, silicon, and boron.
PotteryPottery is the process and the products of forming vessels and other objects with clay and other raw materials, which are fired at high temperatures to give them a hard and durable form. The place where such wares are made by a potter is also called a pottery (plural potteries). The definition of pottery, used by the ASTM International, is "all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products".
Greek Dark AgesThe Greek Dark Ages was the period of Greek history from the end of the Mycenaean palatial civilization, around 1100 BC, to the beginning of the Archaic age, around 750 BC. Archaeological evidence shows a widespread collapse of Bronze Age civilization in the Eastern Mediterranean world at the outset of the period, as the great palaces and cities of the Mycenaeans were destroyed or abandoned. At around the same time, the Hittite civilization also suffered serious disruption, with cities from Troy to Gaza being destroyed.
TravertineTravertine (ˈtrævərˌtiːn ) is a form of terrestrial limestone deposited around mineral springs, especially hot springs. It often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and rusty varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and other speleothems. It is frequently used in Italy and elsewhere as a building material.
Leaching (chemistry)Leaching is the process of a solute becoming detached or extracted from its carrier substance by way of a solvent. Leaching is a naturally occurring process which scientists have adapted for a variety of applications with a variety of methods. Specific extraction methods depend on the soluble characteristics relative to the sorbent material such as concentration, distribution, nature, and size. Leaching can occur naturally seen from plant substances (inorganic and organic), solute leaching in soil, and in the decomposition of organic materials.
Late antiquityLate antiquity was the time of transition from classical antiquity to the Middle Ages, generally spanning the 4th–8th century in Europe and adjacent areas bordering the Mediterranean Basin. The popularization of this periodization in English has generally been credited to historian Peter Brown, after the publication of his seminal work The World of Late Antiquity (1971). Precise boundaries for the period are a continuing matter of debate, but Brown proposes a period between the 3rd and 8th centuries AD.
