Engineering Dictionary

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An alphabetical listing of General terms and items.

Lag   Dico Tools
1. A time delay between the output of a signal and the response of the instrument to which the signal is sent. 2. A time relationship between two waveforms where a fixed reference point on one wave occurs after the same point of the reference wave.

Laminar Flow   Dico Tools
Streamlined flow of a fluid where viscous forces are more significant than inertial forces, generally below a Reynolds number of 2000.

Large Scale Integration (LSI)   Dico Tools
The combining of about 1,000 to 10,000 circuits on a single chip. Typical examples of LSI circuits are memory chips and microprocessor.

Latent Heat   Dico Tools
Expressed in BTU per pound. The amount of heat needed (absorbed) to convert a pound of boiling water to a pound of steam.

Latera Praetorii   Dico Tools
The central area between the via principalis and via quintana, where the head quarters (principia), the commanding officers house (praetorium), the granary (horreum) and sometimes the hospital (valetudiunarium).

Lavra   Dico Tools
Byzantine monastic retreat, sometimes fortified.

Leakage Rate   Dico Tools
The maximum rate at which a fluid is permitted or determined to leak through a seal. The type of fluid, the differential Limits of Error

Least-squares Line   Dico Tools
The straight line for which the sum of the squares of the residuals (deviations) is minimized.

Licence To Crenellate   Dico Tools
A warrant of royal permission to build a castle or to fortify an existing structure such as a manor house.

Life Cycle   Dico Tools
The minimum number of pressure cycles the transducer can endure and still remain within a specified tolerance.

Lilia   Dico Tools
Circular pits provided with sharpened stakes at the bottom in addition to the defences of a Roman fort. An example was found at the Antonine wall fort at Rough Castle.

Limes, Limites   Dico Tools
The frontier barriers of the Roman Empire, using natural barriers where possible and series of castra stativa linked by ramparts topped by palisades.

Limits Of Error   Dico Tools
A tolerance band for the thermal electric response of thermocouple wire expressed in degrees or percentage defined by ANSI specification MC-96.1 (1975).

Line   Dico Tools
A work raised by an army extending from one position or post to another, the army encamped behind the work and used it to guard the territory the work traversed.

Line Of Approach   Dico Tools
A trench dug at right angles from the covert way by the besieged garrison so to enfilade an enemy's position.

Line Of Circumvallation   Dico Tools
Earthworks consisting of a parapet with a ditch in front, punctuated by redans which flank the parapet, built in conjunction with lines of contravallation, and used to defend a besiegers camp and positions against a relieving army.

Linearity   Dico Tools
The closeness of a calibration curve to a specified straight line. Linearity is expressed as the maximum deviation of any calibration point on a specified straight line during any one calibration cycle.

Lines Cremaillere   Dico Tools
Lines of defence consisting of alternating short and long faces at right angles to one another. See cremaillere.

Lines Of Bastions   Dico Tools
A succession of lines of defence consisting of bastioned curtain walls (eg. those of a concentric castle).

Lines Of Contravallation   Dico Tools
See contrevallation, counter vallation.

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Lines Of Defence   Dico Tools
(1) Any artificial, semi-natural or natural obstacle which can be used to impede an enemy's approach (eg. fortification, ditch, terrain, etc.). (2) The distance between a bastions salient angle and the opposing flank; the bastion flank. (3) A series of fortified outposts.

Lines Of Tenailles   Dico Tools
A series of salient and re-entering angles formed by parapets.

Liquid Junction Potential   Dico Tools
The potential difference existing between a liquid-liquid boundary. The sign and size of this potential depends on the composition of the liquids and the type of junction used.

Lis, Liss   Dico Tools
(1) A form of defence similar to a palisade consisting of upright stakes tied together by vines and twigs. (2) An Irish fortification consisting of a circular mound surrounded by a ditch, used as protection for a village.

Lisiere, Liziere   Dico Tools
The berm or walkway along a parapet. 

Lists   Dico Tools
An area set aside for jousting, which was incorrectly applied in the 19th century to the spaces between two lines of curtain wall or a bailey in the mistaken belief that joust took place there. (Teut.).

Load   Dico Tools
The electrical demand of a process expressed as power (watts), current (amps) or resistance (ohms).

Load Impedance   Dico Tools
The impedance presented to the output terminals of a transducer by the associated external circuitry.

Lodgement   Dico Tools
A work made by besiegers in the part of a fortification taken by their actions, and used to hold it against counter attack.

Logarithmic Scale   Dico Tools
A method of displaying data (in powers of ten) to yield maximum range while keeping resolution at the low end of the scale.

Loop Resistance   Dico Tools
The total resistance of a thermocouple circuit caused by the resistance of the thermocouple wire. Usually used in reference to analog pyrometers which have typical loop resistance requirements of 10 ohms.

Loop, Loophole, Loup   Dico Tools
(1) A narrow opening in the wall or merlon of a fortification, through which missiles were discharged at the enemy, positioned to command the approaches, as well as protecting the weak spots. Designed to provide the maximum amount of protection for the defenders as well as give a reasonable field of fire. See arrow loop, gun loop. (2) The circle at the end or at the centre of an arrow slit which was used to increase the field of fire. Also known as an oilet. See arrow loop, arrow slit.

Lorica   Dico Tools
The palisade made from villi or the sharpened stakes lashed together and rammed into the top of the ramparts forming the parapet surrounding a Roman encampment.

Low Artillery Outwork   Dico Tools
See hornwork, ravelin.

LS-TTL Compatible   Dico Tools
For digital input circuits, a logic 1 is obtained for inputs of 2.0 to 5.5 V which can source 20 A, and a logic 0 is obtained for inputs of 0 to 0.8 V which can sink 400 A. For digital output signals, a logic 1 is represented by 2.4 to 5.5 V with a current source capability of at least 400 A; and a logic 0 is represented by 0 to 0.6 V with a current sink capability of at least 16 MA. "LS" stands for low-power Schottky.

LS-TTL Unit Load   Dico Tools
A load with LS-TTL voltage levels, which will draw 20 A for a logic 1 and -400 A for a logic 0.

LSD (Least-Significant Digit)   Dico Tools
The rightmost active (non-dummy) digit of the display.

Lunette   Dico Tools
(1) A small work generally situated before the curtain, in a ditch full of water, consisting of two faces forming a re-entering angle, and was used to enfilade the ditch. (2) A field work consisting of two faces forming a salient angle and to flanks parallel to the capital. (3) A work situated on either side of ravelin, and the other face is perpendicular to half or two thirds of the faces of the ravelin, and the other face is nearly so to the faces of the bastion. (4) A work sited forward of the second ditch, opposite to the places of arms, the same as a ravelin except for its situation. (Fr. lunette, dim. of Lune, moon).

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