Glossary of civil engineering

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This glossary of civil engineering terms pertains specifically to civil engineering and its sub-disciplines. Please see glossary of engineering for a broad overview of the major concepts of engineering.

A

  • Abney level – is an instrument used in surveying which consists of a fixed sighting tube, a movable spirit level that is connected to a pointing arm, and a protractor scale. An internal mirror allows the user to see the bubble in the level while sighting a distant target. It can be used as a hand-held instrument or mounted on a Jacob's staff for more precise measurement.[1][2]
  • Abrams' law – (also called Abrams' water-cement ratio law)[3] is a concept in civil engineering. The law states the strength of a concrete mix is inversely related to the mass ratio of water to cement.[3][4][5][6] As the water content increases, the strength of concrete decreases.
  • Abrasion – is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements.
  • Abrasion resistance
  • Absolute electrode potential – in electrochemistry, according to an IUPAC definition,[7] is the electrode potential of a metal measured with respect to a universal reference system (without any additional metal–solution interface).
  • Absolute pressure – is zero-referenced against a perfect vacuum, using an absolute scale, so it is equal to gauge pressure plus atmospheric pressure.
  • Absolute zero – is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as 0. Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. The theoretical temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as −273.15° on the Celsius scale (International System of Units),[8][9] which equals −459.67° on the Fahrenheit scale (United States customary units or Imperial units).[10] The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition.
  • Absorbance – In chemistry, absorbance or decadic absorbance is the common logarithm of the ratio of incident to transmitted radiant power through a material, and spectral absorbance or spectral decadic absorbance is the common logarithm of the ratio of incident to transmitted spectral radiant power through a material.[11] Absorbance is dimensionless, and in particular is not a length, though it is a monotonically increasing function of path length, and approaches zero as the path length approaches zero.
  • Abutment – refers to the substructure at the ends of a bridge span or dam whereon the structure's superstructure rests or contacts.[12]
  • AC powerPower in an electric circuit is the rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the direction of energy flow.
  • Acceleration – In physics, acceleration is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of any and all forces acting on the object, as described by Newton's Second Law.[13] The SI unit for acceleration is metre per second squared (m s−2). Accelerations are vector quantities (they have magnitude and direction) and add according to the parallelogram law.[14][15] As a vector, the calculated net force is equal to the product of the object's mass (a scalar quantity) and its acceleration.
  • Acid – is a molecule or ion capable of donating a hydron (proton or hydrogen ion H+), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid).[16]
  • Acid-base reaction – is a chemical reaction that occurs between an acid and a base, which can be used to determine pH. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
  • Acid strength – refers to the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a proton, H+, and an anion, A.
  • Acoustic board – is a special kind of board made of sound absorbing materials. Its job is to provide sound insulation.[17][18] Between two outer walls sound absorbing material is inserted and the wall is porous. Thus, when sound passes through an acoustic board, the intensity of sound is decreased. The loss of sound energy is balanced by producing heat energy.
  • Acoustics – is the branch of physics that deals with the study of all mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound.
  • Activated sludge – The activated sludge process is a type of wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa.
  • Activated sludge model –is a generic name for a group of mathematical methods to model activated sludge systems. The research in this area is coordinated by a task group of the International Water Association (IWA). Activated sludge models are used in scientific research to study biological processes in hypothetical systems. They can also be applied on full scale wastewater treatment plants for optimisation, when carefully calibrated with reference data for sludge production and nutrients in the effluent.
  • Active transport – In cellular biology, active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses ATP, and secondary active transport that uses an electrochemical gradient.
  • Actuator – is the mechanism by which a control system acts upon an environment. The control system can be simple (a fixed mechanical or electronic system), software-based (e.g. a printer driver, robot control system), a human, or any other input.[19]
  • Acute angle – an angle that is smaller than a right angle (less than 90°).
  • Adenosine triphosphate – (ATP) is a complex organic chemical that provides energy to drive many processes in living cells, e.g. muscle contraction, nerve impulse propagation, chemical synthesis. Found in all forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer.[20] When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP so that the human body recycles its own body weight equivalent in ATP each day.[21] It is also a precursor to DNA and RNA, and is used as a coenzyme.
  • Adhesion – is the tendency of dissimilar particles or surfaces to cling to one another (cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the cumulative magnitudes of these intermolecular forces, there are also certain emergent mechanical effects.
  • Adiabatic process – In thermodynamics, an adiabatic process is one that occurs without transfer of heat or mass of substances between a thermodynamic system and its surroundings. In an adiabatic process, energy is transferred to the surroundings only as work.[22][23] The adiabatic process provides a rigorous conceptual basis for the theory used to expound the first law of thermodynamics, and as such it is a key concept in thermodynamics.
  • Aerobic digestion – is a process in sewage treatment designed to reduce the volume of sewage sludge and make it suitable[24] for subsequent use.[25] More recently, technology has been developed that allows the treatment and reduction of other[26] organic waste, such as food, cardboard and horticultural waste.
  • Aerodynamics – is the study of the motion of air, particularly its interaction with a solid object, such as an airplane wing. It is a sub-field of fluid dynamics and gas dynamics, and many aspects of aerodynamics theory are common to these fields.
  • Afocal system – In optics an afocal system (a system without focus) is an optical system that produces no net convergence or divergence of the beam, i.e. has an infinite effective focal length.[27]
  • Agricultural engineering – is the engineering discipline that studies agricultural production and processing. Agricultural engineering combines the disciplines of mechanical, civil, electrical and chemical engineering principles with a knowledge of agricultural principles according to technological principles. A key goal of this discipline is to improve the efficacy and sustainability of agricultural practices.[5]
  • Albedo – is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body (e.g. a planet like Earth). It is dimensionless and measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects all incident radiation).
  • Algae
  • Algebra – is one of the broad parts of mathematics, together with number theory, geometry and analysis. In its most general form, algebra is the study of mathematical symbols and the rules for manipulating these symbols;[28] it is a unifying thread of almost all of mathematics.[29] It includes everything from elementary equation solving to the study of abstractions such as groups, rings, and fields. The more basic parts of algebra are called elementary algebra; the more abstract parts are called abstract algebra or modern algebra. Elementary algebra is generally considered to be essential for any study of mathematics, science, or engineering, as well as such applications as medicine and economics. Abstract algebra is a major area in advanced mathematics, studied primarily by professional mathematicians.
  • Algorithm – is an unambiguous specification of how to solve a class of problems. Algorithms can perform calculation, data processing and automated reasoning tasks.
  • Alkane – In organic chemistry, an alkane, or paraffin (a historical name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single.[30] Alkanes have the general chemical formula CnH2n+2.
  • Alkene – In organic chemistry, an alkene is an unsaturated hydrocarbon that contains at least one carbon–carbon double bond.[31]
  • Alkyne – In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond.[32]
  • Alloy – is a combination of metals or of a metal and another element. Alloys are defined by a metallic bonding character.[33]
  • Alternating current – is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans and electric lamps into a wall socket. A common source of DC power is a battery cell in a flashlight. The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.[34][35]
  • Ammeter – is a measuring instrument used to measure the current in a circuit.
  • Amino acidAmino acids are organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid.[36][37][38] The key elements of an amino acid are carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), although other elements are found in the side chains of certain amino acids.
  • Amorphous solid – In condensed matter physics and materials science, an amorphous or non-crystalline solid is a solid that lacks the long-range order that is characteristic of a crystal.
  • Ampere – often shortened to "amp",[39] is the base unit of electric current in the International System of Units (SI).[40][41] It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics.
  • Amphoterism – In chemistry, an amphoteric compound is a molecule or ion that can react both as an acid and as a base.[42] Many metals (such as copper, zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation states of the oxide. Al2O3 is an example of an amphoteric oxide.
  • Amplifier – An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the power of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. An amplifier is a circuit that has a power gain greater than one.[43][44][45]
  • Amplitude
  • Anaerobic digestion
  • Angular acceleration – is the rate of change of angular velocity. In three dimensions, it is a pseudovector. In SI units, it is measured in radians per second squared (rad/s2), and is usually denoted by the Greek letter alpha (α).[46]
  • Anion – is an ion with more electrons than protons, giving it a net negative charge (since electrons are negatively charged and protons are positively charged).[47]
  • Annealing (metallurgy)
  • Anode
  • ANSI
  • Archimedes' principle – states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the center of mass of the displaced fluid.[48] Archimedes' principle is a law of physics fundamental to fluid mechanics. It was formulated by Archimedes of Syracuse.[49]
  • Architecture – is both the process and the product of planning, designing, and constructing buildings or any other structures.[50] Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements.
  • Architectural engineering – also known as Building Engineering or Architecture Engineering, is the application of engineering principles and technology to building design and construction.
  • Arrhenius equation
  • Atom
  • Austenitization
  • Automation – is the technology by which a process or procedure is performed with minimal human assistance.[51] Automation [52] or automatic control is the use of various control systems for operating equipment such as machinery, processes in factories, boilers and heat treating ovens, switching on telephone networks, steering and stabilization of ships, aircraft and other applications and vehicles with minimal or reduced human intervention.
  • Automaton – is a self-operating machine, or a machine or control mechanism designed to automatically follow a predetermined sequence of operations, or respond to predetermined instructions.[53]
  • Autonomous vehicle -

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See also

References

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  4. Abrams law, air and high water-to-cement ratios by ELSEVIER
  5. "ASABE". www.asabe.org. Retrieved 2018-04-13.
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