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Civil Engineering Dictionary

Updated: Mar 28, 2020

Absolute Temperature: The temperature reckoned from the absolute zero temperature. Absolute velocity: The vector sum of the velocity of a fluid parcel relative to the earth and the velocity of the parcel due to the earth's rotation; the east-west component is the only one affected. Absolute Viscosity: Term used interchangeably with viscosity to distinguish it from kinematic viscosity and/or commercial viscosity; occasionally, dynamic viscosity. Absolute zero temperature: Temperature measured from absolute zero (-459.67°F, or -273.16°C). Absorbent: A material which, due to an affinity for certain substances, extracts one or more such substances from a liquid or gaseous medium with which it contacts and which changes physically or chemically, or both, during the process. Calcium chloride is an example of a solid absorbent, while solutions of lithium chloride,lithium bromide, and ethylene glycols are liquid absorbents. Absorber : That part of the low side of an absorption system, used for absorbing vapor refrigerant. Absorption: Act or process of absorbing. Abutment : A concrete support wall constructed at both ends of a bridge or an arch, in order to resist the horizontal force from the bridge or the arch, support the ends of the bridge span and to prevent the bank from sliding under Acid rain: rainwater carrying acidic atmospheric pollutants (nitrous or sulfuric oxides) Acid Rain: Atmospheric precipitation with a pH below 5.6 to 5.7. Burning of fossil fuels for heat and power is the major factor in the generation of oxides of nitrogen and sulfur, which are converted into nitric and sulfuric acids washed down in the rain. Acid rain : Atmospheric precipitation with an pH below 5.6 to 5.7. Acre: Unit of land area in the Imperial system; 4840 square yards, or the equivalent of a rectangular field one chain wide and one furlong long, approximately 4047 square metres or 0.4047 hectares. Activation Energy: The energy required for initiating a metallurgical reaction—for example, plastic flow, diffusion, chemical reaction. The activation energy may be calculated from the slope of the line obtained by plotting the natural log of the reaction rate versus the reciprocal of the absolute temperature. Active earth pressure : The horizontal push from earth onto a wall. The active earth force from sand on to a free retaining wall is equivalent to that from a fluid of density 0.25 to 0.30 times that of the sand. The force from sand on to a fixed retaining wall is very much more. Adhesion: The property of a lubricant that causes it to cling or adhere to a solid surface. Adiabatic: Occurring with no addition or loss of heat from the system under consideration. Adiabatic change : A change in the volume, pressure, or temperature of a gas, occurring without a gain of heat or loss of heat. Adiabatic compression: Compressing a gas without removing or adding heat. Adiabatic cooling : A method in which paramagnetic salts are pre-cooled, and then demagnetized, thereby producing further cooling. Admixture or additive : A substance other than aggregate, cement or water, added in small quantities to the concrete mix to alter its properties or those of the hard concrete. The most important admixtures for concrete are accelerators, air-entraining agents, plasticizers and retarders. Admixtures: Materials added to mortar or concrete to achieve particular modifications to the normal properties of the basic material. Adsorbent: A material which has the ability to cause molecules of gases, liquids or solids to adhere to its internal surfaces without changing the adsorbent physically or chemically. In water treatment, a synthetic resin possessing the ability to attract and to hold charged particles. Adsorption: Assimilation of gas, vapor, or dissolved matter by the surface of a solid or liquid. Aeration: Making contact between air and a liquid by spraying liquid into the air or by agitating the liquid to promote absorption of air. Also act of fluffing molding sand. Aeration: Air trapped in the hydraulic fluid. Excessive aeration causes the fluid to appear milky and components to operate erratically. Aerobic: A condition in which free or dissolved oxygen is present in water. Aggregate: A mixture of sand and stone and a major component of concrete. Aggregate: The stones and sand (coarse and fine aggregate respectively) used as a filler in concrete, asphalt etc. Aggregate: sand, gravel etcmixed with cement to form concrete. Air brick: Ventilation built into brickwork to provide ventilation through the wall. Air-entrained concrete : A concrete used for constructing roads. It has about 5% air and is therefore less dense than ordinary good concrete, but it has excellent freeze-thaw resistance. The strength loss is roughly 5% for each 1% air entrained. Air entrained concrete produced by adding an admixture to concrete or cement, which drags small bubbles of air (Smaller than 1 mm in diameter) into the concrete mix. The bubbles increase the workability and allowing both sand and water contents to be reduced. Air-Hardening Steel: A steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. The term should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 inches or more in diameter. Air-Lift Hammer: A type of gravity drop hammer where the ram is raised for each stroke by an air cylinder. Because length of stroke can be controlled, ram velocity and thus energy delivered to the workpiece can be varied. Alloy: A substance that has metallic properties and is comprised of two or more chemical elements, of which at least one is a metal. Alloy Cast Iron: Highly alloyed cast irons containing more than 3% alloy content. Alloy cast irons may be a type of white iron, gray iron or ductile iron. Alloy Steel: A steel in which a deliberate addition of one or more alloying elements, e.g. Mn, Ni, Cr, Mo, etc. has been made during steelmaking to enhance the properties of the steel. The amounts of each element that must be present in steel before it is classified as an alloy steel are given in Table 1 in EN 10020:2000. At low levels of addition, the steels may be classified as low alloy. The same standard classifies steels which do not meet the minimum requirements as 'non-alloy' steels. Altimeter: An instrument used to measure the height above a reference point, such as ground or sea level. Alumina: Aluminum oxide produced fron bauxite by a complicated chemical process. It is a material that looks like granulated sugar. Alumina is an intermediate step in the production of aluminum from bauxite, and is also a valuable chemical on its own. Aluminum: killed steel steel treated with aluminum as an oxidizing agent in order to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification. Amalgam: A dental alloy produced by combining mercury with alloy particles of silver, tin, copper and sometimes zinc. Ammeter: An instrument for measuring the magnitude of electric current flow. Amplitude: A measure of floor vibration. It is the magnitude or total distance traveled by each oscillation of the vibration. Amplitude: The maximum instantaneous value of alternating current or voltage. It can be in either a positive or negative direction. The greatest distance through which an oscillating body moves from the mid point. Anchor Bolt: An anchor bolt is a specialized bolt used to attach items to hard surfaces such as concrete, asphalt, brick or stone. Anchor bolts are made up of a threaded end that is turned into the surface of interest and a washer and nut used to carry the load on the bolt. Anchor bolts come in many shapes, sizes, and materials depending on the application and the load requirements. Anchorage: The process of fastening a joist or joist girder to a masonry, concrete, or steel support by either bolting or welding. Anion: A negatively charged ion that migrates through the electrolyte toward the anode under the influence of a potential gradient.(see Cation) (see Ion) Anode: 1. The electrode of an electrolyte cell at which oxidation occurs. Electrons flow away from the anode in the external circuit. It is usually at the electrode that corrosion occurs and metal ions enter solution. 2. The positive (electron-deficient) electrode in an electrochemical circuit. Contrast with cathode. Anode: In electrolysis or electrochemical corrosion, a site where metal goes into solution as a cation leaving behind an equivalent of electrons to be transferred to the opposite electron, called the cathode. Anolyte: The electrolyte adjacent to the anode in an electrolytic cell. Antioxidant: An additive to retard oxygen-related deterioration, especially oxidation of lubricants.. (see Inhibitor) Aperature: In an extrusion die, the shaped opening through which the heat-softened metal is forced and which gives the extruded product its cross-sectional shape. Also called the “orifice”. Apex: The highest point of a gable. Apron: Device that the molten slag flows across on its way from the spout to the doughnut. It is cooled by water spray. Aqueduct : a bridge or channel for conveying water, usually over long distances Argon: Argon is a chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble or inert gas. Argon is the third most common gas in the Earth's atmosphere, at 0.93% (9,300 ppm). Artesion well : A spring which water flows naturally out of the earth's surface due to pressure placed on the water by an impervious overburden and hydro-static head. ASTM: American Standard of Testing and Materials Axial Impellers: An axial impeller is the rotating component in an axial flow pump. Also known as the rotor, the impeller contains multiple blades to convert the mechanical energy of the shaft into fluid acceleration and pressure rise as the fluid moves through the pump. Backfill: The replacement of excavated earth into a trench around or against a basement /crawl space foundationwall. Backhoe: a rubber tired vehicle with loader bucket in front and small excavator bucket at back. Balcony: A platform, enclosed by a railing or balustrade, projecting from the face of either an inside or outside wall of a building (e.g. a gallery in a theatre). Ball Mill: A method of obtaining a high luster on small parts by rotating them in a wooden-lined barrel with water, burnishing soap and stainless steel shot. Ballast: Framed walls (generally over 10' tall) that run the entire vertical length from the floor sill plate to the roof. This is done to eliminate the need for a gable end truss. Barge board: Horizontal beam rafter that supports shorter rafters. Barometer: To check the atmospheric pressure a device is used called barometer Barrel (Drum): The sequence of abrupt changes in magnetic induction occurring when the magnetizing force acting on a ferromagnetic specimen is varied. Base Plate: A type of mounting where the hoist is mounted to the top side of a horizontal supporting surface. Bat : A half-brick. Batching: Amount or quantity of core or mold sand or other material prepared at one time. Batching Plants: A batching plant is an installation of equipment for mixing bulk components. It typically refers to a remote installation set up for the purpose of mixing concrete on site. Bearing : (1) The supporting section of a beam length or area. (2) The compressive stress between a beam and its support (bearing pressure), particularly on foundations. (3) The horizontal angle turned between a datum direction such as true north and a given line. Bearing Guides: A bearing guide is a mechanical device used to provide a smooth, controlled surface to guide the movement of another component such as a tool bit. The guide is often a set of concentric cylindrical shells with ball or roller element bearings between the two surfaces. An example of a bearing guide is the small guide often used with router bits in woodworking. Bearing Load: A compressive load supported by a member, usually a tube or collar, along a line where contact is made with a pin, rivet, axle, or shaft. Bearing Test: The shear load on a mechanical joint (such as a pinned or riveted joint) divided by the effective bearing area. The effective bearing area of a riveted joint, for example, is the sum of the diameters of all rivets times the thickness of the loaded member. Bench mark: an elevation reference point. Bernoulli equation : Is an Energy equation for two points along the bottom of an open channel experiencing uniform flow. Bernoulli's Theorem: The simplest aromatic hydrocarbon (C6H6) used in petrochemical processes and as a solvent. It must be used with caution because of its toxicity. For safety considerations, laboratories have substituted other solvents like toluene in its place. Blacking Hole: Irregular shaped surface cavities in a casting containing carbonaceous matter. Caused by spilling off of the blacking from the mold surface. Blasting: A method of cleaning or of roughening a surface by a forceable stream of sharp angular abrasive. Bleeding: The tendency of a liquid component to separate from a liquid-solid or liquid-semisolid mixture, as oil may separate from a grease. Blister: High-carbon steel produced by carburizing wrought iron. The bar, originally smooth, is covered with small blisters when removed from the cementation (carburizing) furnace. Boiler: Tubes which form part of the heating surface of a boiler, as distinct from superheater tubes. The tubes may contain water and be surrounded by the furnace gases as in a water tube boiler, or they may act as flues and be surrounded by water as in smoke tube boiler. Boom: The lower or bottom horizontal member of a truss. Bore: The angle above or below the horizontal axis of the base boom section. Boulder: pieces of rock larger than 200mm Boulders: rocks larger than 30 an (12 inches) in diameter Box culvert: culvert of rectangular cross section, commonly of precast concrete. Box gutter: A timber gutter lined with lead or some other waterproof material. (Fr. chèneau (m) encaissé). Brace: A member, usually a diagonal, which resists lateral loads and/or movements of a structure. Bracing : metal that is attached to a fabrication prior to galvanizing in order to provide support so that the steel does not change shape during heating and cooling; can be temporary or permanent Brick: Building unit of a regular size usually made of baked clay. Can also becalcium silicate or concrete. The standard size of metric bricks in the UK is 65 x 102.5 x 215mm, designed to be used with a 10mm mortar joint. The equivalent theoretical size of imperial bricks, used with a 3/8inch joint, is 2 5/8 x 4 3/16 x 8 5/8 inches. Clay bricks are of course of great antiquity as evidenced by archaeology and the bible. Brick guard: Steel mesh panel used on scaffolding to make sure that loose bricks cannot fall off the scaffold. Brick ledge: The metal angle iron that brick rests on, especially above a window, door, or other opening. Brick lintel: Trim used around an exterior door jamb that siding butts to. Brick mold: A small, corrugated metal strip @ 1 X 68 long nailed to wall sheeting or studs. They are inserted into the grout mortar joint of the veneer brick, and holds the veneer wall to the sheeted wall behind it. Bridge: The crane movement in a direction parallel to the crane runway. Bull dozer: tracked vehicle with front mounted blade. Bulldozer: The microstructure of malleable or ductile cast iron when graphite nodules are surrounded by a ferrite layer in a pearlitic matrix. Bumper (Buffer): (1) A semirefined alloy containing sufficient precious metal to make recovery profitable. (2) Refined gold or silver, uncoined. Bumping: An energy absorbing device for reducing impact when a moving crane or trolley reaches the end of its permitted travel, or when two moving cranes or trolleys come into contact. Cable : SHIELDEDSpecial cable used with equipment that generates a low voltage output. Used to minimize the effects of frequency noise on the output signal. Caisson: An overhang. Where one floor extends beyond and over a foundation wall. For example at a fireplace location or bay window cantilever. Normally, not extending over 2 feet. Calcination: (1) A copper or copper alloy casting rectangular in cross section, used for rolling into sheet or strip. (2) A coalesced mass of unpressed metal powder. Canopy: A projecting member that is supported at one end only. Cantilever: Foundation void material used in unusually expansive soils conditions. This void is trapezoid shaped and has vertical sides of 6 and 4 respectively. Cantilever footing : A combined footing that supports an exterior wall or exterior columns. Capillary: The name given to the thin tube attached to the bulb which transmits the bulb pressure changes to the controller or indicator. The cross sectional area of the capillary is extremely small compared to the cross section of the bulb so that the capillary, which is usually outside of the controlled fluid, will introduce the smallest possible error in the signal being transmitted from the bulb. Capillary Action: These are cargo vessel size categories. Capesize refers to dry bulk carriers that are too big to pass through the Suez or Panama canals. Consequently, they have to go round the Southern tip of Africa (Cape of Good Hope) or South America (Cape Horn). They are usually around 80,000-160,000 deadweight tons but can be larger, and typical cargoes are iron ore and coal. Needless to say, they require deep berths or trans-shipment facilities on arrival. Panamax cargo ships are the largest that can go through the Panama Canal, and are usually about 65,000 dwt. Handymax vessels typically carry dry bulk cargoes like steel, are in the 35,000-60,000 dwt range, and are equipped with on-board cranes. Casing: (1) A flexible material used to seal a gap between two surfaces e.g. between pieces of siding or the corners in tub walls. (2) To fill a joint with mastic or asphalt plastic cement to prevent leaks. Cast iron : a generic term for a large family of cast ferrous alloys Cast-Iron: The process of using gas tungsten arc welding (GTAW), plasma welding, laser welding, or electron beam welding to apply weld heat to melt the edges of the material and allow them to flow together to form a joint. Catalyst: Catalysis is the increase in the rate of a chemical reaction of two or more reactants due to the participation of an additional substance called a catalyst.Unlike other reagents in the chemical reaction, a catalyst is not consumed by the reaction. Cation: The electrolyte adjacent to the cathode of an electrolytic cell. Cavitation: The process of filling the empty space by a solid object. Cavity: Progressive loss of original material from a solid surface due to continuing exposure to cavitation from a solid surface due to continuing exposure to cavitation. Ceiling: Height above ground or water level of the base of the lowest layer of cloud, below 20,000 feet, covering more than half of the sky. Service ceiling also means an aircraft’s DENSITY ALTITUDE at which its maximum rate of climb is lower or equal to 100 feet per minute. The absolute celing is the highest altitude at which the aircraft can maintain level flight. Cement: A man-made or machine-made clay tile used to finish a floor or wall. Generally used in bathtub and shower enclosures and on counter tops. Cement mortar : Mortar usually composed of four parts sand to one of cement, with a suitable amount of water. Centrifugal: type of pump that flings water outwards and into an exit pipe. Centroid: The point in a member at the intersection of two perpendicular axes so located that the moments of the areas on opposite sides of an axis about that axis is zero. Chain: Surveyors' unit of length in the Imperial system. Gunter's chain, named after its inventor,comprises 22 yards or 66 feet, approximately 20.117 metres. Gunter's chain is useful for deriving areas in acres. The lesser-known Engineer's chain, 100 feet long, was used for measuring lineardistances,along roads for example. Chainage: linear distance. Chainage : A length (Usually 100 feet) measured by chain or steel tape. Chamfer: To take off the edge or arise of any material to a small depth at an angle of about 45°. Check Valve: This is two way valve in the shape of T. use to flow the fluids in one direction and at same time flow is closed for other direction Chipping: A small groove ground back of the cutting edge on the top of a cutting tool to keep the chips short. Civil engineer : an engineer who plans, designs, and supervises the construction of facilities essential to modern life Civil engineering works: Works comprising a structure other than a building and its associated site works such as a dam, bridge, road etc or an operation such as dredging, dewatering, soil stabilisation Cladding: Any material used to face a building or structure. Clay: grains of rock less than 0.001mm. Coagulation: Is the process whereby finely divided particles of turbidity and color, capable of remaining in suspension indefinitely, are combined by chemical means into masses sufficiently large to effect rapid settling. Coarse aggregate : (1) For concrete: aggregate which retained on the No. 4 sieve (4.76 mm). (2) For bituminous material: aggregate which retained on a sieve of 3 mm square opening Coarse Grain: Steel melted without aluminum or other grain refiner additions. Coffer : a sunken panel in a ceiling Cofferdam : a temporary dam built to divert a river around a construction site so the dam can be built on dry ground Cohesion: The property of a substance that causes it to resist being pulled apart by mechanical means. Cohesion of soil : The stickiness of clay or silt. It is the shear strength of clay, which generally equals about half its unconfined compressive strength. Collar beam: Preformed flange placed over a vent pipe to seal the roofing above the vent pipe opening. Also called a vent sleeve. Collimator: A device for confining the elements of a beam of radiation within an assigned solid angle. Colloid: A suspension of extremely small particles (5-5,000 angstroms) in a liquid; the particles do not settle and are not easily separated by filtration. Colloids are considered ionized particulates immune to agglomeration. Greases are colloidal systems with thickeners dispersed in lubricating oil. Colloidal: A state of suspension in a liquid medium in which extremely small particles are suspended and dispersed but not dissolved. Colorimeters: A colorimeter is a chemical measuring device used to determine the amount of solute dissolved in a solution. The colorimeter determines the concentration of the solution based on the wavelengths of light that are pass through the solution to a photoresistor that measures the light. Colorimeters make use of optical filters that can be adjusted to the wavelengths of light that pass through the solution of interest. Compaction: (1) The act of forcing particulate or granular material together (consolidation) under pressure or impact to yield a relatively dense mass or formed object. (2) In powder metallurgy, the preparation of a compact or object produced by the compression of a powder, generally while confined in a die, with or without the inclusion of lubricants, binders and so forth. With or without the concurrent applications of heat. Compasses: An instrument for drawing arcs and circles. Not to be confused, incidentally, with a compass (in the singular) which is a magnetic instrument for finding North. Compression, adiabatic: Is compressing a gas without removing or adding heat. Compressive Strength: The maximum compressive stress that a material is capable of developing, based on original area of cross-section. In the case of a material which fails in compression by a shattering fracture, the compressive strength has a very definite value. In the case of materials which do not fail in compression by a shattering fracture, the value obtained for compressive strength is an arbitrary value depending upon the degree of distortion that is regarded as indicating complete failure of the material. Compressor : The pump which provides the pressure differential to cause fluid to flow and in the pumping process increases pressure of the refrigerant to the high side condition. The compressor is the separation between low side and high side. Computer aided design (cad): The type of computer program with which technical drawings are prepared. The market leader is AutoCAD but there are others. Concrete: Beads or drops of water (and frequently frost in extremely cold weather) that accumulate on the inside of the exterior covering of a building. Use of louvers or attic ventilators will reduce moisture condensation in attics. A vapor barrier under the gypsum lath or dry wall on exposed walls will reduce condensation. Concrete: An artifical stone-like substance obtained by mixing large and small stones and sand with cement and enough water to permit fullhydration and make the mix workable. Concrete (like the stone minerals from which it is made) is strong in compression but weak intension. Roman concrete was based, not on Portland cement, but on a 'pozzolanic' mix, made from volcanic ash and incorporating ground-up bricks and tiles. (Fr. beton, m). Concrete pump: A machine for transporting concrete down a delivery pipe. May be truck mounted or static. Condenser : An apparatus used to transfer heat from a hot gas, simultaneously reducing that gas to a liquid. Conduction: The rate at which heat is transmitted through a material. Conductivity: The rate at which heat is transmitted through a material. Conductor: Substance or body capable of transmitting electricity or heat. Cone: The conical part of an oxyfuel gas flame next to the orifice of the tip. Cone Angle: The angle that the cutter axis makes with the direction along which the blades are moved for adjustment, as in adjustable-blade reamers where the base of the blade slides on a conical surface. Consolidation : The gradual, slow compression of a cohesive soil due to weight acting on it, which occurs as water, or water and air are driven out of the voids in the soil. Consolidation only occurs with clays or other soils of low permeability, it is not the same as compaction, which is a mechanical, immediate process and only occurs in soils with at least some sand. Construction: The process of assembling materials and erecting a structure. The medium in which a building is built (eg wood, steel or masonry). Consumption: Measures the physical use of steel by end-users. Steel consumption estimates, unlike steel demand figures, account for changes in inventories. Apparent Supply — Derived demand for steel using AISI reported steel mill shipments plus Census Bureau reported imports, less Census Bureau reported exports. Domestic market share percentages are based on this figure, which does not take into account any changes in inventory. Contact Corrosion: When two disimiliar metals are in contact without a protective barrier between them and they are in the presence of liquid, an electrolytic cell is created. The degree of corrosion is dependent on the area in contact and the electro-potential voltage of the metals concerned. The less noble of the metals is liable to be attacked, i.e., zinc will act as a protector of steel in sea water whereas copper or brass would attack the steel in the same environment. Contact Fatigue: Cracking and subsequent pitting of a surface subjected to alternating Hertzian stresses such as those produced under rolling contact or combined rolling and sliding. The phenomenon of contact fatigue is encountered most often in rolling-element bearings or in gears, where the surface stresses are high due to the concentrated loads and are repeated many times during normal operation. Continuous beam : A beam extending over several spans in the same straight line. Contour: an imaginary line linking points of equal elevation. Contour: The outling of an object. Contour line: A line drawn on a site plan joining points of the same elevation. Contour Machining: Machining of irregular surfaces such as those generated in tracer turning, tracer boring and tracer milling. Convex: The curved surface of a cylinder as a sphere when viewed from the outside. Conveyor: A mechanical apparatus for carrying or transporting materials from place to place. Types include apron, belt, chain, gravity, roller, monorail, overhead, pneumatic, vibrating, etc. Conveyor: A mechanical apparatus for carrying or transporting materials from place to place. Types include apron, belt, chain, gravity, roller, monorail, overhead, pneumatic, vibrating, etc. Coping: The process of removing certain sections of a structural steel member to allow easier fitup to the supporting structural member. Corbel: A strip of formed sheet metal placed on outside corners of drywall before applying drywall 'mud'. Corrosion: Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents. Corrosion Fatigue: Fatigue accelerated by simultaneous attack from a corrosive environment. Corrosion : the chemical or electrochemical reaction between a material and its environment that produces a deterioration of the material and its properties; zinc chemically reacts with elements in the atmosphere, thereby sacrificially corroding to prevent underlying steel corrosion Counterfort: A foundation wall section that strengthens (and generally perpendicular to) a long section of foundation wall Crane: Lifting device which can be fixed or mobile. Crane Service, Heavy: Service that involves operating at 85 to 100% of rated load or in excess of 10 lift cycles/hour as a regular specified procedure. Crane, Cantilever Gantry: A gantry or semigantry crane in which the bridge girders or trusses extend transversely beyond the crane runway on one or both sides. Crawling: A coating defect consisting of a lack of adhesion to, or dewetting of, the substrate while the coating or ink is wet. The cause is due to a difference in surface tension of the coating and substrate. Crawling is also known as cissing and dewetting. Creep: A time-dependent deformation of a structural member under a sustained constant load. Crib: Network of cast iron used to support the cope when no cope flask is used. Curl: Appears as a relatively uniform curvature or sweep along the length of coiled metal. Curtain wall: A non-load bearing exterior wall which carries only its own weight and wind load. Cutting Torch (Arc): A device used in air carbon arc cutting, gas tungsten arc cutting and plasma arc cutting to control the position of the electrode, to transfer current and to control the flow of gases. Cutting Torch (Oxyfuel Gas): A device used for directing the preheating flame produced by the controlled combustion of fuel gases and to direct and control the cutting oxygen. Dado: A groove cut into a board or panel intended to receive the edge of a connecting board or panel. Damp proof course (dpc): A barrier, usually physical, built into masonry to prevent moisture migrating up from the ground or down from above, e.g. chimneys, parapets. Dampproofing: The end of a pipe (the terminal end) that is not attached to anything. Datum: A predetermined level on a site from which all other levels are established. Datum : Any elevation taken as a reference point for levelling. Dead load: The weight of the materials which form a permanent part of the structure, as opposed to imposed load. Decibel: (dB)A decibel is a division of a logarithmic scale for expressing the ratio of two quantities proportional to power or energy. The number of decibels denoting such a ratio is ten times the logarithm of the Deck: A floor or roof covering made out of gage metal attached by welding or mechanical means to joists, beams, purlins, or other structural members and can be galvanized, painted, or unpainted. Deck : (1) A flat roof, a quay, jetty or bridge floor, generally a floor form with no roof over upon which concrete for a slab is placed. (2) Formwork for a level surfaces. Decomposition: breakdown of organic materials Decomposition: Separation of a compound into its chemical elements or components. Deformed Bar: Concrete reinforcing bars in which the surface is provided with lugs or protrusions (called deformations) which inhibit longitudinal movement of the bars relative to the surrounding concrete. The surface deformations are hot formed in the final roll pass by passing the bars between rolls having patterns cut into them so that the surfaces of the bars are forced into the depressions in the rolls to form characteristic deformations. Density index : (relative density): is a measure of the tendency or ability to compact soil during loading. The density index is equal to 1 for a very dense soil; it is equal to 0 for a very loose soil Density Ratio: The ratio of the determined density of a powder compact to the absolute density of metal of the same composition usually expressed as a percentage. Also referred to as percent theoretical density. (see percent theoretical density) Design loads: The loads specified in the contract drawings or specifications which a building is to be designed for. Design pressure : Highest or most severe pressure expected during operation. Sometimes used as the calculated operating pressure plus an allowance for safety. Detergent (Cleansers): Detergents in cleansers are surface-active compounds that lower the surface tension of water or water solutions and impart emulsifying and dispersing properties to them. Dew Point: The dew point of the atmosphere inside the furnace. The higher the negative number, the dryer the furnace. A dry furnace is desired. Dewatering : The removal of groundwater bypumping so as to artificially depress the water table and avoid the difficulties associated with construction below the water table. Diaphragm: Roof panel or decking, metal wall, or floor slab which provides a larger in-plane shear stiffness and strength adequate to transmit horizontal forces to the resisting structural system. Die: A metal block used in forming materials by casting, molding, stamping, threading or extruding. Diffusion: Movement of atoms in solids. Heat provides the energy for atom movement. Dilution : Reducing a concentration of soluble material by adding pure water. Dimensional Tolerance: A range by which a product's width and gauge can deviate from those ordered and still meet the order's requirements. (see Commercial Tolerance) Distillation : Salt removal process from brackish or sea water by boiling and condensation. Diversion: 1. A situation that occurs when a coil/s intended for an order doesn’t meet quality standards or customers specifications and is therefore diverted to meet another customer's specifications. In addition, coils can be diverted to complete another customer's order or for other reasons as necessary. 2. Removing a product from its original order. Diversion: 1.) A situation that occurs when a coil/s intended for an order doesn't meet quality standards or customers specifications and is therefore diverted to meet another customer's specifications. In addition, coils can be diverted to complete another customer's order or for other reasons as necessary. 2) Removing a product from it's original order. Synonymous with Reapplication. Diversion channel : a bypass created to divert water around a dam so that construction can take place Dome : a curved roof enclosing a circular space; a threedimensional arch Door frame: A frame into which a door is fitted. Door head: The upper part of the frame of a door Door jambs: The two vertical members of a door frame. Door leaves: In wide openings, a door may be made up into two or more individual sections or “leaves”,which are hinged together. Dowel: A wood or metal pin used to strengthen a joint by its insertion partly into each of the joined pieces Drainage : the act, process, or mode of becoming emptied or freed of cleaning solutions and/or zinc Draw Peg: A wooden peg used for drawing patterns. Draw Spike: A steel spike used to rap and draw a pattern from the sand; it is driven into the wood of the pattern, as opposed to a Draw Screw, which threaded. Dredge : To dig or excavate under water. Drift: The lateral movement or deflection of a structure. Drop Hammer: A term generally applied to forging hammers in which energy for forging is provided by gravity, steam or compressed air. See also air-lift. Hammer, board hammer, and steam hammer. (see Air-Lift) Drop Hammer Forming: A process for producing shapes by the progressive deformation of sheet metal in matched dies under the repetitive blows of a gravity-drop or power-drop hammer. The process isrestricted to relatively shallow parts and thin sheet from approximately 0.6 to 1.6 mm (0.024 to 0.064 in.). Dry ice : Refrigerating substance made of solid carbon dioxide which changes directly from a solid to a gas (sublimates). Its subliming temperature is -78°C. Dryer: Dries the strip after a rinsing process. Duct: Any tube, pipe or other conduit by which air or fluid is transfered. Ductile: A metal capable of being drawn into wire or thread. Ductility: The ability of a material to deform plastically without fracturing, being measured by elongation or reduction of area in a tensile test, by height of cupping in an Erichsen test or by othermeans. Dumping: Dumping occurs when imported merchandise is sold in, or for export to, the domestic market at less than the normal value of the merchandise, i.e., a price which is less than the price at which identical or similar merchandise is sold in the comparison market, the home market (market of exporting country) or third country market (market used as proxy for home market in cases where home market cannot be used). The normal value of the merchandise cannot be below the cost of production. Dumpy level: An optical levelling instrument Dumpy level: Originally a simple but accurate optical instrument invented in 1832 by English civil engineer William Gravatt. Now applied to any optical levelling instrument used by builders. Dyke : (1) A mound of earth along a river or channel bank to retain floodwater. (2) Large ditch. (3) A tabular-shaped igneous intrusion. Dynamic load: A load that varies with time which includes repeative loads, seismic loads, and other loads created by rapid movement. Dynamite : a blasting explosive, based on nitroglycerin, but much safer to handle than nitroglycerin alone Eccentric: The condition that exists when a load is applied on a line of action that does not pass through the centroid of the body it is applied to. Eddy Currents: A condition caused by an uneven roll surface. It is seen on the edges of a coil, not across the full width of the coil. EDM: Abbreviation for electrical discharge machining. Efflorescence: A white or coloured powder sometimes formed on the surface of masonry by deposit of soluble salts. Effluent: waste liquid from a house, industry, sewagetreatment plant, etc. Ejector: A device mounted in such a way that it removes or assists in removing a formed part from a die. Elastomer: A rubber or rubber-like natural or synthetic material that can be stretched repeatedly and that returns to its approximate original dimensions when the stress is released. Electrical Precipitator: In air pollution control, the use of electrodes in stack emissions emitting high voltage; particles 0.1 micron and smaller can be attached and collected at discharge electrode. Electro Galvanizing: Galvanizing by Electro deposition of zinc on steel Electrode: The device through which current is conducted thru to the arc or base metal during the process of welding. Electrolysis: The separation of a chemical compound into its components by passing an electric current through it. Electrolyte: A dissolved or fused substance capable of conducting an electric current; examples include the molten solution electrolyzed in an aluminum reduction cell, or the acid solution in a wet-cell battery. Electrolytic Galvanized: Cold Rolled or Black Plate to which a coating of zinc is applied by electro deposition; used for applications in which corrosion resistance and paintability is a primary concern. Electromagnetic Radiation: Energy propagated at the speed of light by an electromagnetic field. Electromotive Force: (1) The force that determines the flow of electricity; a difference of electric potential. (2) Electrical potential; voltage. Electrophoresis: Transport of charged colloidal or macromolecular materials in an electric field. Electroplate: The application of a metallic coating on a surface by means of electrolytic action. Electroplating: Electro deposition of a metal or alloy in an adherent form on to a cathodic piece. Elevation: A geometrical drawing of a facade of a building. Embankment : A ridge of earth or rock placed, shaped and compacted to carry a road, railway, canal, etc., or to contain water. Emulsion: Colloidal dispersion of one immiscible liquid in another; the second suspends, but does not dissolve, the first. Emulsions of oil and water are formed either by agitation or with the aid of an emulsifying agent. In the water-in-oil type, water droplets are held in suspension as the internal phase; in the oil-in-water type, oil droplets are held in suspension and water is the continuous phase. Both types exhibit a milky or cloudy appearance. The water-in-oil type is known as an invert emulsion, as the oil is the continuous phase. Enantiotropy: The relation of crystal forms of the same substance in which one form is stable above a certain temperature and the other form is stable below that temperature. For example, ferrite and austenite are enantiotropic in ferrous alloys. Endothermic: A chemical change in which there is absorption of heat. Endothermic Atmosphere: A gas mixture produced by the partial combustion of a hydrocarbon gas with air in an endothermic reaction. Also known as endogas. Engineering brick: A type of brick which is particularly strong and impermeable. The traditional product was blue in colour; other colours and qualities are available. English bond: Alternate rows of bricks consist of all headers and all stretchers. Traditionally considered to be the strongest bond, it is often found in engineering works like bridges and retaining-walls. Entropy -: A thermodynamic measure of the amount of energy unavailable for useful work in a system undergoing change. The ratio of the heat added to a substance to the absolute temperature at which it is added. Environment -: The aggregate of all conditions (such as contamination, temperature, humidity, radiation, magnetic and electric fields, shock, vibration) that externally influence the performance of a material or component. Equalizer: A device which compensates for unequal length or stretch of a rope or chain. Equity: The handling of funds or documents by a third party on behalf of the buyer and/or seller. Erosion: movement of soil by water and wind Ester: Chemical compound produced by the reaction of an acid and an alcohol, resulting in an elimination of a molecule of water. Excavator: generally tracked vehicle with rotating body and front mounted digging arm. Exothermic: A chemical change in which there is liberation of heat. Exothermic Reaction: A reaction that liberates heat, for example the burning of fuel or when certain plastic resins are cured chemically. Expansion joint: Earth that swells and contracts depending on the amount of water that is present.(Betonite is an expansive soil). Fabrication: The manufacturing process to convert raw materials into a finished product by cutting, punching, welding, cleaning, and painting. Fabricator: A producer of intermediate products that does not also produce primary metal. Examples include brass, wire and rod mills which buy copper and other primary or secondary metals to produce brass and other copper alloys or take raw forms of metal and make building,magnet,telecommunications and/or industrial wire,rod and similar products. Factor of safety: Is the ratio of the ultimate load for a member divided by the allowable load for a member and must always be greater than unity. Fahrenheit (°F): On the Fahrenheit thermometric scale, the freezing point of water is 32 degrees Fahrenheit (°F) and the boiling point 212°F (at standard atmospheric pressure). This puts the boiling and freezing points of water exactly 180 degrees apart. Fastener: Term for a connecting device such as a weld, bolt, rivet, etc. Fatigue: The phenomenon leading to fracture under repeated or fluctuating stresses whose maximum value is less than the tensile strength of the material. Ferromagnetic: The ability to become highly magnetic and have the ability to retain a permanent magnetic moment. The elementary magnetic dipoles inside the domain are all oriented in a direction parallel to each other. Ferrous: Metals that consist primarily of iron. Fiber: 1. The characteristic of wrought metal that indicates directional properties. It is revealed by etching a longitudinal section or manifested by the fibrous appearance of a fracture. It is caused chiefly by extension of the constituents of the metal, both metallic and non-metallic, in the direction of working. 2. The pattern of preferred orientation of metal crystal after a given deformation process. Fiber Optics: Fiber optics is the term applied to the study and application of optical fibers in many different applications. Fiber optics makes use of transparent fibers that are capable of transmitting light over long distances, at high bandwidths and with limited signal loss. Fiber optics is guided by the scientific principle of refraction, or the bending of light, first seen experimentally in the 1840's. Practical applications of fiber optics began to appear in the early 1900's and can not be found in engineering sensors, communications, lighting, and media applications. Fibre cement: A product made of cellulose fibre, fillers, Portland cement and water. Filler: A rod, plate, or angle welded between a two angle web member or between a top or bottom chord panel to tie them together usually located at the middle of the member. See Tie or Plug. Fillet: A concave corner piece used on foundry patterns, a radius joint replacing sharp inside corners. Fine aggregate: Sand used in making concrete, mortar etc. Firebrick : A refractory brick, often made from fire clay, that is able to withstand temperature in the range of 1500 to 1600°C, and is used to line furnaces. Flask: A metal frame used for making or holding a sand mold. The upper part is the cope and the bottom half is the drag. Flemish bond: The most common bond in brickwork 225mm or more in thickness, it consists of alternating headers and stretchers, with each header being in the middle of the stretchers above and below. Flocculation: A coating defect consisting of the formation of clusters of particles separable by relatively weak mechanical forces, or by a change in the physical forces at the interface between the liquid and the dispersed particles. Fluorescent lighting: End rafters of the gable overhang supported by roof sheathing and lookouts. Flux: A slag-making ingredient or the increased fluidity of slag. Fly ash -: A finely divided siliceous material formed during the combustion of coal, coke, or other solid fuels. Foreman: Trades foremen, for example foreman plasterer, electrician, are in charge of their tradesmen on a site. The general foreman is in charge of the trades foremen. The term does not specify gender. Formwork: A mould into which concrete is cast. Foundation: The ground upon which the footings of a building are constructed. Fracture: The irregular surface produced when a piece of metal is broken. See also brittle fracture, cleavage fracture, crystalline fracture, decohesive rupture, dimple rupture, ductile fracture, fibrous fracture, granular fracture, intergranular fracture and silky fracture. And transgranular fracture. (see Brittle Fracture) (see Cleavage Fracture) (see Crystalline Fracture) Freeway : A divided arterial highway with full control of access. Frequency: A measure of floor vibration. It is the speed of the oscillations of vibration and is expressed in cycles per secong or Hz (Hertz). Friction: The resisting force tangential to the common boundary between two bodies when under the action of an external force one body moves or tends to move relative to the surface of the other. Fuel Gases: Gases usually used with oxygen for heating such as acetylene, natural gas, hydrogen, propane, stabilized methylacetylene propadiene and other synthetic fuels and hydrocarbons. Fulcrum: The point or support on which a lever turns. Fungicide: A substance that kills, prevents or retards the growth of fungi. Fungicides and biocides are most often used with fluids like soluble oils that contain water. Furlong: Unit of length in the Imperial system; ten chains, or 660 feet, one-eighth of a mile, equal to 201.168 metres. Furnace: Furnace is high temperature having heated chamber which is used for melting the metals to its critical temperature.(The furnace word is coming from Greek work fornex. Which mean OVEN. Fuse: The end, upper, triangular area of a home, beneath the roof. Fusion: A change of state from solid to liquid; melting. Galvanic Cell: (1) A cell in which chemical change is the source of electrical energy. It usually consists of two dissimilar conductors in contact with each other and with an electrolyte, or of two similar conductors in contact with each other and with dissimilar electrolytes. (2) A cell or system in which a spontaneous oxidation-reduction reaction occurs, the resulting flow of electrons being conducted in an external part of the circuit. Gantry : (1) A temporary staging for carrying heavy loads, such as earth. (2) Overhead structure that supports signs, usually built of square timbers or steel joists Gantry Crane: A crane similar to an overhead crane except that the bridge for carrying the trolley or trolleys is rigidly supported on two or more legs running on fixed rails or other runway. Gantry Crane: A gantry is type of overhead crane in which the hoist mechanism is mounted onto trolley mechanism and allowed to move along a set of rails or beams. The gantry may be a fixed structure, or it may be support on wheels allowing the entire gantry structure to be mobile. Gauge: 1. The thickness of the steel strip. 2. An instrument that measures pressure, temperature, level or flow depending on the purpose. Gauge Plate: An alloy tool steel supplied in flat and square section with the surfaces ground to close limits. It is also known as Ground Flat Stock and is used for the manufacturing of gauges, punches, dies, jigs, templates, etc. Generator: The combination of an electrical generator and the steam turbine that drives it to produce electricity. Geodetic: an elevation correlated to international standard. Geological Mapping: Geological Mapping refers to mapping the location of mineral resources, rock formations, or other geological features. Geophysical Surveys: Geophysical Surveys refers to the practice of using a variety of ground measurements to infer information about an areas geology. Methods include measurements of electrical resistivity, electromagnetic radiation, and radar. Girder: The process of installing glass, which commonly is secured with glazier's points and glazing compound. Granular : Material that does not contain more than 35 percent of soil particles which will pass a No. 200 sieve. Graphite: A form of carbon available as natural or synthetic material: natural graphite is either flaky or amorphous, synthetic graphite is crystalline; it is processed to colloidal size and abrasive contaminants are removed from the natural form. Grasshopper: A vibrating unit that is used to carry hot fines from the hot screens to the #21 conveyor belt. Also called the hot fines vibrator. Gravel: rock 0.5 to 7 cm (0.2 to 3 inches) in diameter Gravity dam : a dam constructed so that its great weight resists the force of water pressure Gravity Hammer: A class of forging hammer wherein energy for forging is obtained by the mass and velocity of a freely falling ram and the attached upper die. Examples are board hammers and air-lift hammers. Gravity, specific : Density compared to density of standard material; reference usually to water or to air. Green Sand: A naturally bonded sand or a compounded molding sand mixture which has been tempered with water for use while still in the damp or wet condition. Grid: The completed assembly of main and cross tees in a suspended ceiling system before the ceiling panels are installed. Also the decorative slats (munton) installed between glass panels. Grillage : A footing or part of a footing consisting of horizontally laid timbers or steel beams. Grit: 1. Texture of the surface of a roll; applied through sandblasting and grinding; the lower the number, the higher the grit and the rougher the surface; 50, 90, 150, 200 and 220 grit. Temper mills may run grit. Grit also refers to the finish on the surface of the steel. 2. The size of the shot blast used to mechanically texture a roll for producing a grit finish product. Grooving : The process of producing grooves in a concrete pavement surface to improve frictional characteristics. Grout: A flat wood, plywood, or similar type member used to provide a connection at the intersection of wood members. Most commonly used at joints of wood trusses. They are fastened by nails, screws, bolts, or adhesives. Gusset: A shallow channel or conduit of metal or wood set below and along the (fascia) eaves of a house to catch and carry off rainwater from the roof. Gutter: Drywall. Wall board or gypsumA panel (normally 4' X 8', 10', 12', or 16')made with a core of Gypsum (chalk-like) rock, which covers interior walls and ceilings. Halogens : Substance containing fluorine, chlorine, bromine and iodine. Hardener: An alloy containing at least some aluminum and one or more added elements for use in making alloying additions to molten aluminum. Also referred to as “master alloy”. Haunch: Protection against damage caused by fire, windstorms, or other common hazards. Many lenders require borrowers to carry it in an amount at least equal to the mortgage. Heartwood: The more durable inner part of tree trunk where cells seem only to provide support to the tree. Hedge : A row of closely planted shrubs forming a fence. Helix: A path formed as a point advances uniformly around a cylinder as the thread on a screw or the flutes on a drill. Hertz: Term used to describe the frequency in an AC circuit. Essentially the same as cycles. If a circuit is 60 Hz or 60 cycles, that means that the AC wave has gone through 60 complete waves in one second. High tensile steel: A grade of steel stronger than mild steel, which may be used both in structural steelwork and concrete reinforcement. High-Carbon Steel: Steel with more than 0.3% carbon. The more carbon that is dissolved in the iron, the less formable and the tougher the steel becomes. High-carbon steel’s hardness makes it suitable for plow blades, shovels, bedsprings, cutting edges, or other high-wear applications. Homogeneous material: A material having the same engineering design properties throughout. Honey combs: An exterior water faucet (sill cock). Hooke's law: The linear relationship of forces and deformations, or stresses and strains. Humidity, absolute : The weight of water vapor per unit volume. Hydraulic Hammer: A gravity-drop forging hammer that uses hydraulic pressure to lift the hammer between strokes. Hydraulic Jacks: A Hydraulic Jack is a device that uses fluid power to provide lifting force. It can be thought of as two cylinders connected in series, used to provide a mechanical advantage. Hydrocarbon: A compound composed of carbon and hydrogen, the basic elements of countless organic compounds and the principal constituents of petroleum. Hydrocarbons in petroleum fall into three basic categories: the straight-chain paraffins (aliphatic); the cyclic (ring) chain (naphthenic) and the cyclic chain (aromatic). Hydrometer: An instrument for determining the specific gravity or the API gravity of a liquid. Hydrophilic: Having an affinity for water. Hydrophobic: Lacking affinity for water: incapable of uniting or mixing with water. Hysteresis: A term that describes the behavior of a structural member subjected to reversed, repeated load into the inelastic range whose plot of load verses displacement is characterized by loops. The amount of energy dissipated during inelastic loading is indicated by the enclosed area within these loops. Ignitors: Devices which employ a high-energy electrical spark to ignite the pilot gas flame. Impact load: A weight that is dropped or a dynamic load generated by movement of a live load such as vehicles, craneways, etc. Impeller: the rotational element that actually contacts and moves the water. Impervious : Resistant to movement of water; a description of relatively waterproof soils such as clays through which water percolates at about one millionth of the speed with which it passes through gravel. Inductor: A device consisting of one or more associated windings for introducing inductance into an electric circuit with or without a magnetic core. Inert Gas: A gas that will not support combustion or sustain any chemical reaction; e.g., argon or helium. Infiltration: drainage of water through soil Influence line: An influence line is a curve whose ordinates give the values of some particular function (shear, moment, reaction, etc.) in an element due to a unit load acting at the point corresponding to the particular ordinate being considered. Influence lines for statically determinate structures are straight lines and for statically indeterminate structures the lines are curved and their construction involves considerable analysis. Influent: The solution which enters an ion-exchange unit. Infrared Rays: Pertaining to or designating those rays which lie just beyond the red end of the visible spectrum, such as are emitted by a hot non incandescent body. They are invisible and nonactinic and are detected y their thermal effect. Their wave lengths are longer than those of visible light and shorter than those of radio waves. Can be applied in the foundry for drying or core baking operations and for heating dies. Infrared radiant heat are synonymous. Insulation: Any material used to reduce heat transfer in a roof or building. Insulator: A material of such low electrical conductivity that a flow of current through it can usually be neglected. Similarly, a material of low thermal conductivity, such as that used to insulate structures. Interpolation : (1) Inferring the position of a point between known points on a graph by assuming that the variation between them is smooth. Usually the assumption is that the variation is linear (A straight line variation). (2) To estimate untested values which fall between tested values. Invar: An alloy having practically no expansion when heated; 36% Ni, 0.5% Mn, 0.2% C, and the balance Fe. Iron Oxide: This material as prepared for foundry use generally contains about 85% ferric oxide and is produced by pulverizing a high grade of pure iron ore. It can be added to core sand mixes to assist in keeping the core from cracking before the metal solidifies during the casting operation and also helps to resist metal penetration during this period. Added to molding sand mixtures for control of finning and veining. Also may reduce carbon pickup. Isentropic process: A process carried out reversibly without energy interchange as heat. Also a processes carried out with no entropy change. Isobaric process -: An isobaric process is a thermodynamic process in which the pressure remains constant. This is usually obtained by allowed the volume to expand or contract in such a way to neutralize any pressure changes that would be caused by heat transfer. Isolate: (Isolation) To remove a boiler, or any particular part or system of a boiler, form service by closing the manual valves. Isothermal: Changes of volume or pressure under conditions of constant temperature. Isotope: One of several different nuclides having the same number of protons in their nuclei, and hence having the same atomic number, but differing in the number of neutrons and therefore in the mass number. Joist: The metal latch plate in a door frame into which a doorknob plunger latches. Kerb: An upstand. A raised edging to a pavement or path. Kiln: A furnace for the calcination or firing of ceramic materials, including refractories. Kilonewton: One thousand Newtons – the unit of force in the SI system. Newtons are very small, and the kiloNewton is the practical unit most often used by engineers. In imperial terms it is approximately equivalent to the weight of two hundredweights. Abbreviation kN. Kilowatt-hour: A measure of electrical energy consumption. 1000 watts being consumed per hour. AbbreviatedkWh. Kinematic Viscosity: Value obtained by dividing the absolute viscosity of a fluid by its mass density. Kink: (1) for rolled products, an abrupt bend or deviation from flat which is caused by localized bending during handling. (2) for extrusions, an abrupt deviation from straightness. A kink can be caused by handling. Knot: Bonding together two or more layers of materials. Laminar: flow condition with no waves, eddies etc. Rarely encountered in open channel flow. Laser: A device that produces a concentrated coherent light beam by stimulating electronic or molecular transitions to lower energy levels. Laser is an acronym for light amplification by stimulated emission of radiation. Lath: The wooden perimeter frame lumber member that bolts onto the face of a foundation wall and supports the wood structural floor. Lattice: Space lattice. Lattice lines and lattice planes are lines and planes chosen so as to pass through collinear lattice points, and non collinear lattice points, respectively. Ledger (for a structural floor): A method used to treat/dispose of sewage in rural areas not accessible to a municipal sewer system. Sewage is permitted to be filtered and eventually discharged into a section of the lot called a leech field. Leveling: The process by which a leveling machine flattens metal strip, coil, or sheets by bending it up and down over the interrupting arcs of upper and lowers sets of long, slender work rolls. Lewis: A device consisting of expanding wedges used for lifting heavy stone masonry. Liquation: (1) The separation of a low-melting constituent of an alloy from the remaining constituents usually apparent in alloys having a wide melting range. (2) Partial melting of an alloy usually as a result of coring or other compositional heterogeneities. Liquefaction : The change of state from a gas to a liquid. (The term liquefaction is usually used instead of condensation when referring to substances which are in a gaseous state at ordinary pressures and temperatures.) Live load: Loads on a member that are not permanent and are likely to be moved at some point in the life of the structure. They can be loads produced by the use and occupancy of the building. These loads do not include dead load, wind load, snow load, or seismic load. Loader: wheeled or tracked vehicle with wide front mounted bucket to scrape and load trucks. Lubricant: Substance interposed between two surfaces in relative motion for the purpose of reducing the friction and/or wear between them. Lubrication: Reduction of friction or wear between two load-bearing surfaces by the application of a lubricant; includes boundary lubrication (thin or interrupted fluid film, especially bearings where wear occurs); mixed film, where some liquid pools support the load; elastohydrodynamic (high-pressure loads increase the lubricant’s viscosity and load carrying capacity, especially in gears); hydrodynamic (a thick fluid film lubrication, especially in journal bearings) and hydrostatic (external pump pressure used to form a thick fluid film, as in start-up of journal bearings).Lubrication, bath: , (see lubrication, flood). Machine Drawing: An engineering drawing which depicts the final size and shape of the part for its end use. Magnesite: A mineral consisting essentially of magnesium carbonate. It is the main ingredient used in basic refractories. Magnetic flux : The rate of flow of magnetic energy across or through a surface. Magnetic Pole: The area on a magnetized part at which the magnetic field leaves or enters the pan. It is a point of maximum attraction in a magnet. Malleable: Capable of being extended or shaped by hammering or rolling. Manhole: Hole in the ground to allow access to underground services; access chamber. Manifold: A conductor with multiple connection ports, generally made from a solid block of metal with internally drilled passageways to minimize the amount of piping required. Manometer: Pressure measuring device. Mastic: Sheets of metal that are slit to form openings within the lath. Used as a plaster base for walls and ceilings and as reinforcing over other forms of plaster base. Matalloid: (a) Element intermediate in luster and conductivity between the true metals and non metals. Arsenic, antimony, boron, tellurium, and selenium, etc., are generally considered metalloids; frequently one allotropic modification of an element will be non metallic, another metalloid in character. Obviously, no hard and fast line can be drawn. (b) In steel metallurgy, metalloid has a specialized, even if erroneous, meaning; it covers elements commonly present in simple steel; carbon, manganese, phosphorus, silicon and sulfur. Median : That portion of a divided highway separating the travelled ways for traffic in opposite directions including inside shoulders. Melting Point: The temperature at which a pure metal, compound or eutectic changes form solid to liquid; the temperature at which the liquid and the solid are in equilibrium. Membrane: A thin sheet or layer. Metal lath: Plastic, transparent copies of a blueprint. Metallic Glass: A noncrystalline metal or alloy commonly produced by drastic supercooling of a molten alloy by molecular deposition, which involves growth from the vapor phase (e.g., thermal evaporation and sputtering) or from a liquid phase (e.g., electroless deposition and electrodeposition), or by external action techniques (e.g., ion implantation and ion beam mixing). Meuller-breslau principle: Is a simple method to draw approximate shapes of influence lines. Micron: 10-6 m; one millionth of a meter. Microscopic: Visible at magnifications above 25x. Mile: Unit of length in the Imperial system; 1760 yards, equal to 1609.344 metres. Mill: (1) A factory in which metals are hot Mobility: Analogous to fluidity, the property of a lubricating grease that permits flow under pressure, as in centralized grease dispensing systems. Mobility is evaluated by low-temperature testing that simulates winter field conditions. Modulating : Type of device or control which tends to adjust by increments (minute changes) rather than by either full on or full off operation. Modulus of elasticity: A measure of the amount by which something can be deformed by a force and recover when the force is removed. Modulus of Rigidity: Of a material suffering shear, the ratio of the intensity of the shear stress across the section to the shear strain, i.e., to the angle of distortion in radians; expressed in pounds or tons per square inch. Modulus Of Rigidity: In a torsion test the ratio of the unit shear stress to the displacement caused by it per unit length in the elastic range. See Shear Modulus Modulus Of Rupture: Used in both bending and torsion testing. In bending, the modulus of rupture is the bending moment at fracture divided by the section modulus. In torsion, modulus of rupture is the torque at fracture divided by the polar section modulus. Mold: An iron-casting container used to hold and cool molten metal as it solidifies. Molding: A mixture of cement (or lime) with sand and water used in masonry work. Monolithic: Any structure made of a continuous mass of material or cast as a single piece Monomer : A molecule, usually an organic compound, having the ability to join with a number of identical molecules to form a polymer. Mortar: A company that borrows money from a bank, lends it to consumers to buy homes, then sells the loans to investors. Moulding: Timber (or other material in imitation of timber) shaped into a pattern and used for decorative details such as skirting, picture rail and so on. Traditional moulding shapes include quadrant, ogee, torus, chamfered,glass bead, half round, dowel and so on. Muller: A type of foundry sand-mixing machine. Neoprene : Synthetic rubber resistant to chemical compound, oil, light, etc Notching: Cutting out various shape from the edge of a strip, blank or part. Nozzle: Loose hemp or jute fiber that's impregnated with tar or pitch and used to caulk large seams or for packing plumbing pipe joints Nucleus: 1. The first structurally stable particle capable of initiating recrystallization of a phase or the growth of a new phase, and separated from the matrix by an interface. 2. The heavy central core of an atom, in which most of the mass and the total positive electrical charge are concentrated. Offset: When a coil sidewall is winding up straight and suddenly moves in or out to another position and then continuing to wind up straight. Ohm’s law : The relationship between current and voltage in a circuit. It states that current is proportional to voltage and inversely proportional to resistance. Expressed algebraically, in DC circuits I=E/R; in AC circuits I=E/R. Optical Pyrometer: A temperature measuring device through which the observer sights the heated object and compares its incandescence with that of an electrically heated filament whose brightness can be regulated; or the intensity of the light emitted from the object may be varied through filters and compared with a constant light source. Organic Acid: An organic compound with acid properties, obtained from such organic substances as animal, vegetable and mineral oils; for example, a fatty acid. Chemically, organic acids most often contain a carboxyl group (COOH). Oriffice: An opening of controlled size used to measure or control the flow of gases. Osmosis : The passage of water through permeable membrane separating two solutions of different concentration; the water passes into the more concentrated solution. Oval: A hot rolled carbon steel bar product which is oval in cross section. Oxidation : The reaction of an element or substance with oxygen, e.g., iron is oxidized by reaction with oxygen to form rust (iron oxide). Oxide: Usually refers in the steel industry to oxide of iron, of which there are three principal ones: FeO, Fe3O,4, Fe2O3. In addition, there are many mixtures of these oxides which form on the surface of steel at different temperatures and give the steel different colors, such as yellow, brown, purple, blue and red. Oxides must be thoroughly removed from the surface of steel objects which are to be coated with tin, zinc, or other metals. (see Scale) Oxidizing Agent: A compound that causes oxidation, thereby itself being reduced. Pans: The area beneath the conveyor belts in the coal bucket area. Paraffin Wax: A high-VI crystalline substance removed from paraffinic crudes after distillation, composed of unbranched straight chain hydrocarbons that are solid at room temperature.Waxes are primarily used for waterproofing and candles; in small quantities, they degrade the low-temperature properties of lubricants. Parapet: A wall that subdivides spaces within any story of a building or room. Pascal: The SI unit of measure for stress or force per unit area (N/m^2). Pascal’s Law: Axiom stating that the pressure on a confined fluid is transmitted undiminished and with equal force to all equal areas of the container. Passive pressure : A pressure acting to counteract active pressure. Pavement : The uppermost layer of material placed on the travelled way or shoulders. This term is used interchangeably with surfacing. Peak hour : The hour during the morning andevening when the greatest number of Pedestal: Tests that a soil engineer performs on earth to determine the feasibility of installing a leech field type sewer system on a lot. A test to determine if the soil on a proposed building lot is capable of absorbing the liquid affluent from a septic system. Pedestal: A metal box installed at various locations along utility easements that contain electrical, telephone, or cable television switches and connections. Penetration: Condition where molten metal has penetrated into the sand, resulting in a mixture of metal and sand adhering to the casting. Permeability: A powdered solid used in paint or enamel to give it a color. Petrolatum: Product made from the residuals of paraffinic crudes, consisting primarily of high molecular weight amorphous waxes, with some grades containing microcrystalline waxes. It is pale to yellow in color, with oily or grease-like characteristics, used in some lubricants and rust preventives or as a lay-up lubricant for some kinds of wire rope. Pier: A masonry column; a jetty. Pier cap : The top part of a bridge pier which uniformly distribute the concentrated loads from the bridge over the pier. Pier shaft : The part of a pier structure which is supported by the pier foundation. Pig Iron: Hot metal or blast furnace product cast to ingots. Pigment: A powdered solid used in paint or enamel to give it a color. Pipe arch: a squished CMP culvert that has greater invert width. Pit : Any borrow pit, mine, quarry or surface excavation to obtain sand, clay, gravel, etc. Plastic limit : The water content at the lower limit of the plastic state of a clay. It is the minimum water content at which a soil can be rolled into a thread of 1/8 inch diameter without crumbling. Plumb bob: The plumbing drain and waste lines that are installed beneath a basement floor. Plunger (Lube Systems): Slide valve that controls the valve port. Ply: Cement made by heating clay and crushed limestone into a brick and then grinding to a pulverized powder state. Plywood: A vertical framing member usually designed to carry a beam. Often a 4 x 4, a 6 x 6, or a metal pipe with a flat plate on top and bottom. Pneumatic : Operated by air pressure. Pointing: The surface treatment of the mortar between bricks or other masonry units. There are various styles of pointingflush, struck and weathered, recessed, tuck, bucket handle etc. (Fr. jontoiement, m). Poisson's ratio: Defined as the ratio of the unit lateral strain to the unit longitudinal strain. It is constant for a material within the elastic range. For structural steel, the value is usually taken as 0.3. It gradually increases beyond the proportional limit, approaching 0.5. Polarity: The direction of current flow in a DC circuit. By convention, current flows from plus to minus. Electron flow is actually in the opposite direction. Polarization: (1) The change from the open-circuit electrode potential as the result of the passage of current. (2) A change in the potential of an electrode during electrolysis, such that the potential of an anode becomes more noble, and that of a cathode more active than their respective reversible potentials. Often accomplished by formation of a film on the electrode surface. Polarization : the partial or complete polar separation of positive and negative electric charges in a nuclear, atomic, molecule or chemical system Polyesters: Synthetic resins, usually obtained from polymerization of a dibasic acid with a dihydric alcohol, not normally used as lubricant stocks. (see Diester (Dibasic Acid Ester)) Polymers: Organic compounds created by polymerization that become progressively heavier and acquire diverse properties as the multiple linkages increase. The original monomer may be a gas or a liquid; according to the extent of polymerization, the final product will be a high molecular weight liquid or solid that retains the same proportion of elements as the original monomer. Polyolesters: A class of synthetic esters formed by reacting fatty acids with a polyol such as glycol; physical properties vary according to the polyols and acids used. Polyolesters formulated as lubricants have low volatility and good oxidation stability at high temperatures; they are used as base oils for turbines, compressors, jet engines and automotive engines and as base fluids for certain greases. Ponding: The gathering of water at low or irregular areas on a roof. Porosity: the percentage of open spaces between pieces of gravel cobble etc. Portland cement: A component of concrete and mortars which combines with water to provide the cement agent. Named for its resemblance to Portland stone. Post-tensioning : A method of pressurising concrete in which the cables are pulled or the concrete is jacked up after it has been placed. This method is usual for bridges and heavy structures which are placed in place. Precast concrete: Concrete components made in a factory or yard and transported to the site. Precipitation: A process whereby salts drop or come out of a water solution. Precision : Of a measurement, the fineness with which it has been read, therefore, precision is different from accuracy. Prime coat : The initial application of a low viscosity bituminous material to an absorbent surface, preparatory to any subsequent treatment, for the purpose of hardening or toughening the surface and promoting adhesion between it and the superimposed constructed layer. Purlin: A horizontal structural member which supports a sloping roof covering, with or without rafters, and which carries the roof loads to the primary framing members. Putty: A man-made or machine-made clay tile used to finish a floor or wall. Generally 6 X 6 X 1/4 thick Pvc (polyvinyl chloride): A widely used plastic - the main uses include water pipes, waste pipes and floor covering. Pyrometry: A method of measuring temperature with any type of temperature indicating instruments. Quartzite: A compact granular rock composed of quartz. It is a metamorphosed sandstone, and siliceous cement is often so blended with the quartz grains as to give the rock a nearly homogeneous texture. Primary material in silica brick. Quicklime : Unslaked lime (calcium oxide). Rack : An array of gears spaced on a straight bar. Racking: A tem used to describe the placing of metal parts to be heat treated on a rack or tray. This is done to keep parts in a proper position to avoid heat-related distortions and to keep the parts separated. Rebar : Refers to steel rods, which are put infootings and grade beams in a concrete foundation. Refractive Index: (ASTM D 1218) number indicating the angle through which a ray of light is deflected as it passes through a solid or fluid medium; the number that expresses the ratio of the sine of the angle of incidence to the sine of the angle of refraction. Typically used for monitoring water-based fluids or solutions. Rehabilitation : The improvement of an existing roadway surface by improving the existing surface or by removing (milling) a specified thickness of the existing pavement and placement of additional pavement layers. Reinforced: To strengthen by the addition of new or extra material (e.g. reinforced concrete, steel rods are embedded to give additional strength). Relative humidity (rh): The ratio of water vapor in the air as compared to the maximum amount of water vapor that may be contained. Resolution: The capacity of an optical or radiation system to separate closely spaced forms or entities; also, the degree to which such forms or entities can be discriminated. Retaining wall: A wall designed to resist the lateral displacement of soil, water, or any other type of material. Retentions: The board placed on the ridge of the roof onto which the upper ends of other rafters are fastened. Reverse osmosis : A process that reverses (by the application of pressure) the flow of water in the natural process of osmosis so that it passes from the more concentrated to the more dilute solution. Revert: Recycled sprues, gates, risers, defective castings and machine chips. Reynolds Numbers: Used in hydraulics and in casting gating theory. A dimensionless value (dynamic viscosity/density) describing the fairly sudden shift of flow from laminar to turbulent. Re >2,000 represents turbulent flow. Laminar flow is seldom experienced in runner and gating systems. Rheology: The study of the deformation and/or flow of matter in terms of stress, strain, temperature and time. Apparent viscosity and penetration of grease are examples of rheological properties. Right-of-way : A general term denoting land, property of interest therein, usually in a strip, acquired for or devoted to transportation purposes. Riser: Each of the vertical boards closing the spaces between the treads of stairways. Rivet: Before structural steel I and H sections became available engineers made up sections by joining narrow plates together using steel rivets with a head formed by hammering while red-hot. Rivets are no longer used for connecting structural steelwork in the UK, with fabrications mostly replaced by ready made sections, and with bolting and welding available which are both faster and safer for connections. The presence of rivets in an existing structure can help in dating it, and usually indicates steelwork dating to before about the 1950s. Roller: (1) In rolling mill terminology, a part of a roller table which transports steel from stand to stand as contrasted with roll which is a part of a stand of rolls and serves to reduce the cross-section of the steel specimen which is being rolled. (2) Term applied to the man in charge of the actual rolling. Runway: The rails, beams, brackets and framework on which the crane operates. Rust : corrosion product consisting of hydrated iron oxides; this term is applicable only to ferrous (iron containing) alloys Rusting: Corrosion mechanism of iron and steel when iron oxide is formed. Passive stainless steel does not rust, but iron or steel contamination on the surface will, which gives consumer a false impression concerning the stainless steel itself. Passivation of stainless steel parts in a nitric acid solution will remove this contamination while maintaining the passivity of the stainless steel surface. Safety Factor: The ratio of burst pressure to rated pressure under specific static pressure and temperature conditions. Sag: Semi-Autogeneous Grinding mill. Used in mineral extraction to grind ore to a fine consistency for further extraction processes. Sapwood: Wood from outside of trunk, usually high in starch Scaffold: A framework for temporary access to building works. The traditional way to build a scaffold in the UK used to be with timber poles connected together with wire bonds. Standardised 1 15/16 inch (49mm) steel tube with proprietary steel connectors came into widespread use after the second world war, based on war surplus tubing that had been used in beach defenses. Various proprietary scaffolding systems are also available and may cost less, but tube and fittings scaffolding has the advantage of flexibility. Scaffolding: A temporary structure specifically erected to support access platforms or working platforms. Scour: localized erosion of substrate and banks by river flow. Scouring: (1) A wet or dry cleaning process involving mechanical scrubbing. (2) A wet or dry mechanical finishing operation, using fine abrasive and low pressure, carried out by hand or with a cloth or wire wheel to produce satin or butler-type finishes. Scrap: Iron or steel discard, or cuttings, or junk metal, which can be reprocessed. Scrapers: aquatic invertebrates that feed by scraping the surface of rocks for algae Sediment : Any material, mineral or organic matter deposited by water, air, etc., often called silt. Segment: A part of the mandrel that moves in and out to expand to hold a coil or collapse to release a coil. Segregation: Nonuniform distribution of alloying elements, impurities or phases. Separator: A tank type pressure vessel installed in a steam pipe to collect condensate to be trapped off and thus providing comparatively dry steam to the connected machinery. Sheave: A grooved wheel or pulley used with a rope or chain to change direction and point of application of a pulling force. Sheet piles : Closely set piles of timber, reinforced or pressurised concrete, or steel driven vertically into the ground to keep earth or water out of an excavation Shrub: small to medium plant of woody character generally with multiple stems. Sigmet: Significant Meteorological Information. A type of weather advisory regarding severe weather conditions (thunderstorms, turbulence, icing, volcanic ash, etc.) which could pose a threat to all types of aircraft. AIRMET is a less inclusive type of advisory. Silt : sediment particles ranging from 0.004 to 0.06 mm (0.00016 to 0.0024 inch) in diameter Sludge: A deposit on a heat transfer surface that does not have the hard, crystalline structure of a scale but is softer and less dense. Sluice gate: a manually or automatically operated sliding or rotating panel to restrict flow into or out of a culvert Slump: The area below the eaves and overhangs. The underside where the roof overhangs the walls. Usually the underside of an overhanging cornice. Slump cone: A mould into which concrete to be tested by the ‘Slump Test’ is placed, which is of standard construction in the form of a cone Slurry: A term loosely applied to any clay-like dispersion. It may be used to wash ladles or other refractory linings to impart a smooth surface; as a bonding addition to molding sand; as a thin loam over specially made molds or as a mixture to fine joints or cracks of a core, etc. Soffit: A large pipe that carries liquid and solid wastes to a sewer or septic tank. Solidification: The change in state from liquid to solid upon cooling through the melting temperature or melting range. Soundness : Resistance to both physical and chemical deterioration. Splice: The connection between two chord members or other structural members joined at their ends by welding or bolting to form a single, longer member. Spout: A trough through which the metal flows from the furnace to the ladle. Stability: The property of a body to maintain its shape and remain rigid when detached from its support. Stack: 1. A component of a hydraulic system that runs an individual function of that system. 2. The boiler exhaust pipe. Each stack is equipped with a stack cap for isolating the boiler from the atmosphere and two butterflies for directing the gases. Stiff : (adj.) ability to resist deformation; stiffness (n.) the measure of a structure's capacity to resist deformation Stiffener: A member used to strengthen another member against buckling or to distribute load or to transfer shear. Usually a flat bar, plate, or angle welded perpendicular to the longitudinal axis of the member. Stovl: Short Take-Off and Vertical Landing. Strut: A structural member used as a brace to resist axial forces. Subbase course : One or more layers of specified or selected materials, of designed thickness, placed on the subgrade to support a base course. Subgrade : The roadbed materials beneath the pavement structure. The top prepared surface of the subgrade is called finished subgrade elevation. Sublimation: A change of state directly from solid to gas without appearance of liquid. Suction: A partial vacuum due to wind loads on a building which cause a load in the outward direction. Tachometer: An instrument used to measure the revolutions per minute (rpm) of a rotating shaft of a turbine. Tandem: tandem axle (rear) dump truck. Tandem roller : A road roller having rolls (drums) of about the same diameter behind each other on the same track. Tendon : A pressurising bar, cable, rope, strand or wire. Thermal Cracking: A process utilizing heat to break high molecular weight substances into smaller units; facilitated in a controlled manner during refining by the presence of a catalyst. Tie Bar: Bar or rod shaped part of the casting added to prevent distortion caused by uneven contraction between separated members. Timber: Wood used for building applications Torsion: Stain created in a material by a twisting action. Correspondingly, the stress within the material resisting the twisting. Transformation: A constitutional change in a solid metal, e.g., the change from gamma to alpha iron, or the formation of pearlite from austenite. Transistor: An active semiconductor device used for providing power amplification and having three or more terminals. A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. Transverse Direction: A direction perpendicular to the direction of working Trench: In joinery, a groove. In drainage and plumbing, the excavation in which pipes are laid. In foundations, the excavation in which footings are placed Truss: An engineered and manufactured roof support member with “zig-zag” framing members. Does the same job as a rafter but is designed to have a longer span than a rafter. Turfing : The covering of an earth surface with growing grass cut from another site. It can also be revetment to slopes which are usually covered by water, made by laying turves on the slope according to a technique like sliced block work. Uniaxial Stress: A state of stress in which two of the three principal stresses are zero. See also principal stress (normal). (see Principal Stress (normal)) Upstream: The inlet side of an instrument, a pump, valve, etc.. Vacuum pump : Special high efficiency device used for creating high vacuums for testing or drying purposes. Valley: The internal angle formed by two inclined slopes of a roof of an internal corner. Water Column: Device to which the water glass is mounted. The water column is connected to the top and bottom of the steam drum through piping and the water seeks the same level in the column as it is in the boiler. This coupled with the water glass and level controller allows the water level in the boiler to be controlled and measured. Weathering: Exposure of materials to the outdoor environment. Weathering Steel: A steel using alloying elements such as copper, chromium, silicon and nickel to enhance resistance to atmospheric corrosion. (Refer to ASTM A 606) Wedge: In any given coil, the variance in width from one edge to the opposite edge. Because USSM buys narrow width (12 to 14) coils slit from wider coils, the wedge effect presents an ongoing problem in shape and gauge control. Welding Fabrication: Welding fabrication is a production process that uses welding to assemble components and produce a final part. The welding fabrication process uses a heat source to melt the adjoining workpieces and a a filler material is added to the joint, mixing with the melted material, and finally hardening into the weld joint. There are many different kinds of welding, with the heat source being supplied by fire, electricity, and lasers, among others. Workability: The characteristic or group of characteristics that determines the ease of forming a metal into desired shapes. Wrinkling: A coating defect consisting of the formation of small ridges or folds in the coating which resemble the surface of a prune, but are usually smaller in size. Wrought Iron: An iron produced by direct reduction of ore or by refining molten cast iron under conditions where a pasty mass of solid iron with included slag is produced. The iron has a low carbon content. Young's Modulus: The coefficient of elasticity of stretching. For a stretched wire, Young’s Modulus is theratio of the stretching force per unit cross-sectional area to the elongation per unit length. The values of Young’s Modulus for metals are of the order 10(12) dynes per square cm.

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