Related Concept Videos

Biodeterioration01:28

Biodeterioration

Biodeterioration refers to the unwanted alteration of materials caused by microorganisms—especially fungi—which damage both organic substrates (paper, wood, textiles) and inorganic ones (stone, plaster, glass). Unlike abiotic decay, biodeterioration results from biological activity that produces physical disruption and chemical degradation.Physical deterioration occurs as fungal hyphae penetrate pores, cracks, and surface irregularities. Hyphal turgor pressure, thigmotropic growth along...
Mortar Joint Deterioration in Masonry01:13

Mortar Joint Deterioration in Masonry

Mortar joint deterioration is a significant concern in masonry structures, with water accumulation in the joints leading to damage from freeze-thaw cycles. The repeated expansion of water during freezing and its melting during thawing develop and propagate cracks in the masonry joints. Eventually, this leads to the spalling of mortar from the joints, loosening masonry units and weakening the structure. The deteriorated mortar joints are also vulnerable to moisture intrusion into the walls.
The...
Lumber Defects01:23

Lumber Defects

Lumber defects, which can affect both the appearance and structural integrity of wood, include a variety of growth and manufacturing flaws. Growth defects such as knots and knotholes occur where branches were once attached to the tree trunk, with knotholes forming when these knots fall out. Other natural defects include decay and insect damage, which compromise the wood's strength and durability.
Shakes are minor fractures that run along or across the wood's annual rings, while wane is...
Keystone Species01:39

Keystone Species

Measures of species biodiversity, such as richness (i.e., the number of species present) and evenness (i.e., their relative abundance), describe an ecological community’s structure. Many factors affect community structure, including abiotic factors (e.g., sunlight and nutrients), disturbances (e.g., fire or flood), species interactions (e.g., predation or competition), and chance events (e.g., foreign species invasion). Certain species—such as keystone species—also play a pivotal role in the...
Wood Surfacing01:14

Wood Surfacing

Wood surfacing is a critical finishing process designed to smoothen the wood surface, enhance its dimensional accuracy, and make handling safer. This process compensates for potential shrinkage during the seasoning phase by marginally increasing the wood dimensions before surfacing. It also helps correct some distortions that may occur as the wood dries.
The equipment used in the surfacing process is a plane equipped with rotating blades. This tool efficiently smoothens the wood surface and can...
Segregation in Fresh Concrete01:16

Segregation in Fresh Concrete

Segregation in fresh concrete is a phenomenon where the components of the concrete mix separate, leading to uneven distribution and compromised structural integrity. This separation typically occurs when concrete is subjected to excessive horizontal movement within forms, or when it is dropped from considerable heights or forced through narrow, winding paths. As a result, heavier coarse aggregate particles settle at the bottom, while lighter, finer materials such as cement and water rise to the...