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E

A mode of learning that takes place electronically, often via the Internet. It requires students to use electronic devices such as computers, tablets and cell phones, usually their own. E-Learning allows learners to conduct sessions at a time and place of their choice and at their own pace, as long as they have access to a device and a Wi-Fi or data connection.

E-stop

An emergency stop switch

EEPROM

Electrically Erasable Programmable Read-Only Memory. A form of memory often used for PLC project backup.

EMI Cable

Electromagnetic Interference Cable. An electrical cable used between a variable speed controller and its motor designed to reduce electromagnetic interference.

EN

The mnemonic for the "Enable" bit in many common functions. The rung remains true while the instruction is executing.

ESD

Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between two objects at different electrical potentials. The term is usually used in the electronics and other industries to describe momentary unwanted currents that may cause damage to electronic equipment.

ESDS

Another cause of ESD damage is through electrostatic induction that is later discharged to an ESD sensitive device, or ESDS. This occurs when an electrically charged object is placed near a conductive object isolated from ground. The presence of the charged object creates an electrostatic field that causes electrical charges on the surface of the other object to redistribute. Even though the net electrostatic charge of the object has not changed, it now has regions of excess positive and negative charges.

EXCLUSIVE NOR Gate

A logic gate that produces a logic 1 output only when all of its inputs are the same (either logic 1's or logic 0's) and produces a logic 0 output when its inputs are not all the same.

EXCLUSIVE OR Gate

A logic gate that produces a logic 1 output when only one of its inputs is a logic 1. It will produce a logic 0 output if it has more than one input of logic 1 or if it has no logic 1 inputs.

Ear muffs

A form of hearing protection consisting of large, padded covers for the entire ear, used to protect from discomfort and hearing loss from noise.

Ear plugs

A form of hearing protection that fits inside the ear canal to filter out noise.

Earth Ground

A conductor that wilt dissipate large electrical currents into the earth

Eccentralizer, Eccentralized

A device or hardware used to position equipment adjacent to the formation, away from the center of the borehole, so that it runs eccentralized.

Eccentricity

A condition that results when a rotating component, such as a turbine shaft, is bent or out of round

Economically producible

A resource that generates revenue that exceeds, or is reasonably expected to exceed, the costs of the operation.

Economizer

A component that transfers heat from combustion gases leaving a boiler to feedwater flowing into the boiler, preheating the water before it enters.

Ediacaran Period

The Ediacaran is a geological period that spans 96 million years from the end of the Cryogenian Period at 635 Mya to the beginning of the Cambrian Period at 538.8 Mya.

Edison-base

The threaded base that is used on standard screw-base plug fuses.

Effective (RMS) Voltage

A value equal to roughly 70% of the peak voltage. Multimeters measure RMS (root mean square) voltages, while oscilloscopes measure peak or peak-to-peak voltages.

Effective Bits

A measure of a digital oscilloscope's ability to accurately reconstruct a signal. Because actual errors include noise and distortion, the frequency and amplitude of the signal, as well as the bandwidth of the instrument, must be specified.

Effective Permeability

A measure of the conductance of a porous medium for one fluid phase when the medium is saturated with more than one fluid. When a second phase is present, the permeability to each phase is referred to as its effective permeability.

Effective Porosity

The interconnected pore volume, or void space, in a rock that contributes to fluid flow in a reservoir. Porosity not considered effective includes water bound to clay particles and isolated vuggy porosity. Only the effective porosity contributes to hydrocarbon production.

Effective Values

AC values based on the relationship that one ampere, peak value, of AC current produces the same heating effect as .707 amperes of DC current; also called RMS values

Effective Voltage

In AC circuits, the voltage based on the relationship that one ampere peak value of AC current produces the same heating effect as 0.707 amperes of DC current. Also, the voltage that actually exists in a stator, combining applied voltage with opposing and aiding voltages.

Efficiency

The amount of energy expended to do work divided by the amount of energy supplied

Effluent

The liquid or process fluid that is discharged from any of the various stages of wastewater treatment or from process equipment (e.g., reactor effluent).

Eight-bit Word

A digital expression of 8 bits; for example, 0100 0111.

Elastic Neutron Scattering

Elastic neutron scattering is where the neutron "bounces" off the nucleus without exciting or destabilizing it. The neutron loses energy with each elastic interaction.

Elastic Wave

Elastic wave propagation involves motion in a medium in which, when particles are displaced, a force proportional to the displacement acts on the particles to restore them to their original position.

Elastic Waves

An elastic wave is a motion in a medium in which, when particles are displaced, a force proportional to the displacement acts on the particles to restore them to their original position.

Elasticity

The characteristic of a solid that causes it to try to return to its original shape after being deformed by stress

Elbow

A type of fitting that is used to change the direction of a conduit run

Elective Training

Depending upon client-selected system settings, users may either self-assign or request approval to take elective courses. Administrators can approve or decline requests, link users or groups of users to a course or courses, set expiration dates and modify or delete elective training linked to a user.

Electric Control System

A safety control system in which an unsafe condition signals the ignition system to ground, shutting off the fuel supply to the prime mover.

Electric Power Supply

A device, or a group of devices, that converts normal generated AC power into power that is suitable for use with electronic equipment.

Electrical Diagram

A diagram that uses symbols to represent the components and connections of an electrical system.

Electrical Distribution System

A system that distributes electric power from a substation.

Electrical Interlock

A circuit arrangement intended to prevent energizing an electrical device in a way that could damage it or that could be unsafe

Electrical shock

The physical reaction of the body to current flow through it.

Electricity

The movement of electrons

Electrochemical Analyzers

Analyzers in which the analysis is based on the interaction of electrical current with a sample material

Electrode

An electrical conductor through which electricity enters or leaves a non-metallic part of a circuit, such as a formation rock during well logging.

Electrofacies

Electrofacies are numerical combinations of petrophysical log responses that reflect specific physical and compositional characteristics of a rock interval; they are determined by multivariate procedures that include principal components analysis, cluster analysis, and discriminant analysis.

Electrolyte

A substance that, when dissolved in water, forms a solution that can conduct electric current. This liquid solution is also generally referred to as an electrolyte.

Electrolyte Solution

An electrolyte solution is a solution that generally contains ions, atoms or molecules that have lost or gained electrons, and is electrically conductive. For this reason they are often called ionic solutions.

Electrolytic Capacitor

A type of polarized capacitor that provides more capacitance in a small space than most other types of capacitors.

Electromagnetic Analyzers

Analyzers that use radiation from specific bandwidths along the electromagnetic spectrum to monitor various properties of sample materials

Electromagnetic Coupling

Transfer of electrical power from one circuit to another circuit through variations in the magnetic field.

Electromagnetic Field (EMF)

A field of magnetic flux cause by electrical current passing through a conductor.

Electromagnetic Induction

The process by which an electromotive force is produced within a conductor when there is relative motion between the conductor and a magnetic field. In transformers, the process by which power is transmitted from a primary winding to a secondary winding via an expanding and contracting magnetic field.

Electromagnetic Methods

Electromagnetic methods are a group of techniques in which natural, or artificially generated, electric or magnetic fields are measured in boreholes in order to map the variations in the formation's electrical properties, resistivity, permeability or permittivity.

Electromagnetic Propagation Logging Tools

Electromagnetic propagation logging tools measure the properties of electromagnetic waves as they move through a formation. Propagation resistivity logs work between about 100 kHz and 10 MHz. Dielectric propagation logs work between 20 and 200 MHz. Logs made above 200 MHz and into the GHz range are known as electromagnetic propagation logs.

Electromagnetic Radiation

Electrical and/or magnetic energy moving through space

Electromagnetic Spectrum

The range of different types of electromagnetic radiation

Electromagnetic Switch

A device that uses electromagnets to open or close a circuit

Electromagnetic Wave

Electromagnetic waves (EM) are waves that are created as a result of vibrations between an electric field and a magnetic field.

Electromagnetic drill

An electric drill used to cut metal It has an electromagnetic base that is energized to secure the drill in place against the work.

Electromagnetic field

A physical field produced by electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction.

Electromagnetism

Magnetism that is created by current flowing through a conductor.

Electromotive Force

An electromotive force is a difference in potential that tends to give rise to an electric current.

Electron

A negatively charged particle that orbits around the nucleus of an atom.

Electrons

The electron is a subatomic particle carrying a negative electric charge. It has no known components or substructure. Therefore, the electron is generally believed to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton.

Electrostatic material

Charged materials also have an electrostatic field and lines of force associated with them.

Electrostatic precipitator

An emission control device that uses plates, wires, and an electrostatic field to remove contaminants or catalyst particles from a gas or flue gas stream before it is released to the atmosphere.

Elevation drawing

A side view of a building or diagram showing the locations of major pieces of equipment relative to a certain elevation, usually sea level, showing height but no interior detail.

Elevator

An elevator is a hinged mechanism that may be closed around drill pipe, or other drill string components, to facilitate either lowering them into the wellbore or lifting them out of the wellbore.

Elevator, Elevators

An elevator is a hinged mechanism that may be closed around drill pipe, or other drill string components, to facilitate either lowering them into the wellbore or lifting them out of the wellbore.

Emergency

Any occurrence, such as equipment failure, rupture of containers, or failure of control equipment, that results or could result in an uncontrolled release of a hazardous substance or endangerment of personnel.

Emergency Shutdown

An unplanned or unscheduled furnace shutdown; a situation in which a furnace is shut down immediately to reduce the risks of danger and damage

Emergency response

A response effort by employees from outside the immediate release area or by other designated responders (e.g., mutual aid groups, local fire departments) to an occurrence that results, or is likely to result, in an uncontrolled release of a hazardous substance.

Emissions

Substances that are discharged into the air.

Emitter

One element of a transistor. In a bi-polar transistor, the emitter is one of the poles.

Employee

An individual employed in a laboratory workplace who may be exposed to hazardous chemicals in the course of his or her assignments.

Employee Assessment (EA)

See, Self-Assessment

Employee Statement [evidence]

As part of knowledge evidence, an employee may provide a personal statement how they would respond to a situation that might arise, describing the process, procedure and/or response to a situation. The Assessor would confirm the content of the statement by questioning the employee further.

Emulsified Asphalt

A type of liquid asphalt produced by mixing straight-run asphalt and chemically-treated water.

Emulsifying Agent

The substance which determines the stability of an emulsion by forming a film around the suspended droplets.

Emulsifying Agents

Substances which hold emulsions together, such as asphalt, paraf¬fins, some minerals, etc.

Emulsion

A mixture of two liquids that do not normally mix (such as oil and water), held together by emulsifying agents. The general name given to the mixture of fluids in a well stream.

Emulsion Stability

Measured by the degree of difficulty in breaking the emulsion; affected by several factors.

Encoder

A feedback device typically used with a variable speed controller to monitor the position and speed of a shaft by generating pulses as the shaft turns.

End grinder

A medium-sized portable power grinder with a shaft that runs parallel to the axis of the tool casing. The grinding wheel or other attachment is located at one end of the grinder. Also called a pencil grinder or a horizontal grinder.

Endless Sling

A continuous loop of wire rope or synthetic material sometimes called a grommet sling

Endothermic Reaction

A reaction that absorbs or requires heat to keep going.

Endothermic reactions

Chemical reactions that absorb heat.

Ene

A suffix for the name of a hydrocarbon whose carbon atoms are linked together by at least one double bond.

Energized

The state of a conducting device, or material, that is electrically connected to a source of electric current.

Energy

The ability or capacity for doing work, existing in several forms that can be converted from one to another. Electrical energy is usually measured in kilowatt-hours, while heat energy is usually measured in British thermal units.

Energy Source

A component that provides the energy necessary for a system to perform its task

Energy control program

A program that helps ensure that machinery is not energized and is inoperative while it is being serviced or maintained.

Engine hour meter

An instrument on a forklift's dashboard that records the total number of hours the engine has been in operation.

Engineering Units

The physical measurement units in which process measurements are calculated and displayed, such as psi, cubic meters per hour, inches of water, or gallons per minute.

Engineering controls

Controls (e.g., sharps disposal containers, self-sheathing needles) that isolate or remove the bloodborne pathogens hazard from the workplace.

English system

The system of linear measurement that includes yards, feet, and inches

Engulfment

The surrounding and effective capture of a person by a liquid or finely divided (flowable) solid substance that can be aspirated to cause death by filling or plugging the respiratory system or that can exert enough force on the body to cause death by strangulation, constriction, or crushing.

Enhanced Hydrocarbon Recovery

Enhanced hydrocarbon recovery, sometimes termed tertiary recovery, is the extraction of hydrocarbons from a producing field which cannot be recovery otherwise.

Enhanced Oil Recovery

Enhanced oil recovery (EOR), or tertiary recovery, is a process for extracting oil that has not already been retrieved through the primary or secondary oil recovery techniques.

Enhanced oil recovery (EOR)

One or more methods applied to an underground reservoir after the primary production phase to improve recovery of hydrocarbons and make it more productive or productive again.

Enhancement type MOSFET

A type of MOSFET that does not have a channel between the source and drain. Current flow is controlled by the capacitance effect between the gate and the substrate. The enhancement type MOSFET will only conduct when the gate potential is opposite to the polarity of the source.

Entrained Gas

Gas dissolved in the well-stream liquids.

Entropy

Entropy is a lack of order or predictability; gradual decline into disorder.

Entry

The action by which a person passes through an opening into a permit-required confined space. Entry includes ensuing work activities in that space and is considered to have occurred as soon as any part of the entrant's body breaks the plane of an opening into the space.

Entry permit (permit)

The written or printed document that is provided by the employer to allow and control entry into a permit space and that contains the information specified in paragraph (f) of the OSHA Permit Required Confined Space Standard.

Entry supervisor

The person (such as the employer, foreman, or crew chief) responsible for determining if acceptable entry conditions are present at a permit space where entry is planned, for authorizing entry and overseeing entry operations, and for terminating entry.

Envelope

In oscilloscopy, the outline of a signal's highest and lowest points acquired over many repetitions. In electronics, the circle drawn around a transistor symbol to indicate a discrete component.

Environmental assessment

A study that can be required to assess the potential direct, indirect and cumulative environmental impacts of a project.

Epicondylitis

Inflammation of the tendons located at the elbow that control wrist movements. Depending on which tendon is involved, it is referred to as tennis elbow or golfers elbow.

Epithermal Neutron Porosity Measurement

A measurement based on the slowing down of neutrons between a source and one or more detectors that measure neutrons at the epithermal level (between approximately 0.4 and 10 eV). The slowing down process is dominated by hydrogen. By measuring neutrons at the epithermal rather than thermal level, the response is a purer estimate of hydrogen index, unaffected by thermal absorbers.

Epithermal Neutrons

Epithermal neutrons (0.025 eV; 0.4 eV) are neutrons of kinetic energy greater than thermal.

Equal spread method

A type of parallel offset in which the side-by-side pipes remain a constant distance apart before, during, and after the offset.

Equal-Pressure Torch

A type of torch in which oxygen and acetylene are mixed in a mixing chamber inside the torch body

Equalizer

The cross bar connecting the pitman arms to the walking beam.

Equalizer Bearing

The pivot point between the equalizer and the walking beam. This can be either a journal bearing or a roller bearing.

Equalizer plate

A rigging connector that has three or more holes and is commonly used to level loads when the sling legs are of unequal length

Equation

A statement showing that the mathematical expressions on each side of an equal sign are equivalent

Equilateral triangle

A triangle that has three equal sides and three equal angles

Equilibrium

A state of balance

Equilibrium (static) state

The state of a body at rest; the conditions that exist in a transistor when no biasing potential is applied.

Equilibrium Reaction

A reversible reaction; a reaction in which reactants form products and products revert back into reactants

Equipment Arrangement Diagram

A drawing showing the exact location of major equipment in a system; often referred to as a floor plan.

Equipment Location Index

A reference that typically lists, identifies, and gives the location of equipment

Equivalent Circulating Density

The effective density exerted by a circulating fluid against the formation that takes into account the pressure drop in the annulus above the point being considered.

Equivalent fractions

Fractions that have the same value but are expressed with different numerators and different denominators

Ergonomic risk factors

Factors that when severe enough, or after a long enough period to time, either alone but especially in combination, can result in an MSD. Ergonomic risk factors include awkward postures, force, repetition, static postures, contact stress vibration, and cold temperatures.

Ergonomics

The science of fitting jobs to people. Ergonomics, which encompasses knowledge about physical abilities, limitations and other human characteristics, is used to prevent MSDs.

Error

The difference between the set point and the value of a process variable (also called deviation). In variable speed controllers, the difference between the command signal and the feedback signal.

Estimated ultimate recovery (EUR)

The sum of reserves remaining as of a given date and cumulative production as of that date.

Eth

A prefix for the name of a hydrocarbon that has two carbon atoms.

Ethane

A colorless, odorless, light gaseous hydrocarbon (C2H6) belonging to the paraffin series. Used especially to make ethylene, the first step in making plastics.

Ethernet

A communications protocol used to allow the implementation of large local area and wide area networks

Etiologic

Of or relating to the branch of medical science concerned with the causes and origins of diseases; the term “etiologic agent” is synonymous with “infectious substance.”

European Community (EC)

European countries that have formed a single trading bloc.

Evacuated Cylinder

A sample cylinder which has had the air removed from it by use of a vacuum pump.

Evaporate

To change from a liquid state to a gaseous or vapor state.

Evaporation

The process by which a liquid changes to a gas or vapor state; the conversion of water droplets to water vapor.

Evaporator

The component in a refrigeration system that removes heat from a heat source. Also, an auxiliary vessel that uses heat transfer to vaporize and remove a portion of a liquid stream from a process unit.

Evaporite

An evaporite is a water-soluble mineral sediment that results from concentration and crystallization by evaporation from an aqueous solution.

Evaporite, Evaporitic

An evaporite is a water-soluble mineral sediment that results from concentration and crystallization by evaporation from an aqueous solution.

Examples

Information included in Chapter 9 of the NEC to demonstrate how to perform load calculations for various types of buildings, feeders, and branch circuits

Excavation Effect

The excavation effect is that part of the effect of gas on the neutron porosity measurement that is not explained by differences in the hydrogen index. By using the concept of hydrogen index, the only significant contributor to the neutron porosity in a gas zone is the liquid-filled porosity, since the hydrogen indices of gas and matrix are close to zero. However, the resultant liquid-filled porosity is found to be too low. The error comes from treating the gas-filled porosity as matrix. If this matrix is excavated and replaced with gas, the correct response can be predicted.

Excelsior

Sometimes called "hay" and is used for filtering oil and water emulsions.

Exceptions

Information in the NEC that follows code sections. Exceptions describe alternative methods, to be used under specific conditions, to the rules stated in the corresponding code sections.

Excess Air

The amount of air that is supplied to a furnace in excess of the theoretical minimum amount required for combustion.

Excess flow valve

A check valve that cuts off flow of product or vapor to a pressure tank car when flow rates exceed limits.

Excitation

Current flow that creates the magnetic field that causes induction in an AC generator.

Excited State

An excited state is any state with energy greater than the ground state.

Exciter

A device that produces and supplies direct current to a generator's rotor windings for AC generator excitation.

Exhaust Gas

The gas produced when fuel burns in a boiler furnace. Exhaust gas must be pushed or drawn out of the furnace and discharged from the plant through the stacks

Exothermic Reaction

A reaction that produces heat after it is started.

Exothermic reactions

Chemical reactions that give off heat.

Expand

To increase in volume or size.

Expander-Compressor

A machine which transfers energy from one gas stream to another by use of an expander and centrifugal compressor mounted on a common shaft.

Expansion Joint

A type of coupling that is used to compensate for expansion and contraction in a conduit run

Expansion Valve

The component in a refrigeration system that lowers the refrigerant's temperature and pressure by allowing it to expand rapidly before flowing to the evaporator.

Exploration Phase

The phase of petroleum operations which covers the search for oil or gas by carrying out detailed geological and geophysical surveys followed by exploratory drilling.

Exploration Process

The exploration process attempts to discover potentially commercial volumes of hydrocarbons through the successful drilling of well-defined exploration prospects, for which the risk of failure has been defined and reduced as much as cost effectively possible for each prospect, within its own subsurface context and its uncertainties.

E

E&P

E-learning