AN - Engineering Definitions: Updated Periodically

analogue Pertaining to data in the form of continuously variable physical quantities. Contrast with digital. A waveform is analogue if it is continuous and varies over an arbitrary range.

analogue back up An alternate method of process control by conventional analogue instrumentation in the event of a failure in the computer system.

analogue control Implementation of automatic control loops with analogue (pneumatic or electronic) equipment. analogue signal An analogue signal is a continuously variable representation of a physical quantity, property, or condition such as pressure, flow, temperature, etc.

analogue simulation The calculation of the time or frequency domain response of electrical circuits to input stimulus. It assembles and solves a set of simultaneous equations associated with circuit topology.

angle of repose A characteristic of bulk solids equal to the maximum angle with the horisontal at which an object on an inclined plane will retain its position without tending to slide; the tangent of the angle of repose equals the coefficient of static friction.

angle valve A valve design in which one port is colinear with the valve stem or actuator, and the other port is at right angles to the valve stem.

angstrom A unit of length defined as 1/643 8.4696 of the wavelength of the red line in the Cd spectrum; largely replaced by the SI unit nanometer, or 10 9 meters.

angular momentum The product of a body's moment of inertia and its angular velocity.

angular momentum flowmeter A device for determining mass flow rate in which an impeller turning at constant speed imparts angular momentum to a stream of fluid passing through the meter; a restrained turbine located just downstream of the impeller removes the angular momentum, and the reaction torque is taken as the meter output. Also called an "axial flowmeter."

angular velocity Rate of motion along a circular path, measured in terms of angle traversed per unit time.

anhydrous Describing a chemical or other solid substance whose water of crystallisation has been removed.

anisotropic Exhibiting different properties when characteristics are measured along different directions or axes.

annealing Treating metals, alloys or glass by heating and controlled slow cooling, primarily to soften them and remove residual internal stress.

annular nozzle A nozzle whose inlet opening is ring shaped rather than an open circle.

annunciator A device or group of devices that call attention to changes in process conditions that have occurred. Usually included are sequence logic circuits, labeled visual displays, audible devices, and manually operated acknowldege and reset push buttons.

antialias filter A low-pass filter designed to block frequencies greater than one-half the measuring rate.

anti cavitation trim A combination of plug and seat ring or plug and cage that by its geometry permits noncavitating operation or reduces the tendency to cavitate, thereby minimising damage to the valve parts, and the downstream piping.

anti noise trim A combination of plug and seat ring or plug and cage that by its geometry reduces the noise generated by fluid flowing through the valve.

anti reset windup Device or circuit that prevents the saturation of the integral mode of a controller that develops during times when control cannot be achieved. Helps to prevent the controlled variable from overshooting its set point when the obstacle to control is removed.

anti surge control Control by which the unstable operating mode of compressors known as "surge" is avoided.

An Overview of Laser Technology

The word laser is an acronym that stands for "light amplification by stimulated emission of radiation." In a fairly unsophisticated sense, a laser is nothing more than a special flashlight. Energy goes in, usually in the form of electricity, and light comes out. But the light emitted from a laser differs from that from a flashlight, and the differences are worth discussing. You might think that the biggest difference is that lasers are more power- ful than flashlights, but this conception is more often wrong than right. True, some lasers are enormously powerful, but many are much weaker than even the smallest flashlight. So power alone is not a distinguishing characteristic of laser light.
Now it'senough to say that there are three differences between light from a laser and light from a flashlight. First, the laserbeam is much narrower than a flashlight beam. Second, the white light of a flashlight beam contains many different colors of light, while the beam from a laser contains only one, pure color. Third, all the light waves in a laserbeam are aligned with each other, while the light waves from a flashlight are arranged randomly. The significance of this differ- ence will become apparent as you read through the next several chapters about the nature of light.

Lasers come in all sizes—from tiny diode lasers small enough to fit in the eye of a needle to huge military and research lasers that fill a three-story building. And different lasers can produce many different colors of light. As we explain in Chapter 2, the color of light depends on the length of its waves. Listed in Table 1.1 are some of the important commercial lasers. The "light" produced by carbon dioxide lasers and neodymium lasers can- not be seen by the human eye because it is in the infrared portion of the spectrum. Red light from a ruby or helium-neon laser, and green and blue light from an argon laser, can be seen by the human eye. But the krypton-fluoride laser's output at 248 nm is in the ultraviolet range and cannot be directly detected visually. Interestingly, few of these lasers produce even as much power as an ordinary 100-W lightbulb. What's more, lasers are not even very efficient. To produce 1W of light, most of the lasers 1 would require hundreds or thousands of watts of electricity. What makes lasers worthwhile for many applications, however, is the narrow beam they produce. Even a fraction of a watt, crammed into a supernarrow beam, can do things no lightbulb could ever do.

The ruby, yttrium aluminum garnet (YAG), and glass lasers listed are solid-state lasers. The light is generated in a solid, crystalline rod that looks much like a cocktail swizzlestick. All the other lasers listed are gas lasers, which generate light in a gaseous medium like a neon sign. If there are solid- state lasers and gaseous lasers, it's logical to ask if there's such a thing as a liquid laser. The answer is yes. The most common example is the organic dye laser, in which dye dissolved in a liquid produces the laser light.

TOTAL - a global energy group

As the fifth largest publicly-traded integrated oil and gas company in the world and a major actor in the chemicals business, Total has operations in more than 130 countries on five continents with approximately 97,000 employees.
To meet growing energy needs on a long-term basis, Total’s strategy involves deploying a sustainable growth model combining the acceptability of its activities with a sustained program of profitable investments.
Our ambitions:

* preparing for future energies, i.e. innovating and pursuing our research efforts to support the development of new energies and to contribute to moderating demand;

* developing our corporate policy based on responsibility, diversity, mobility and fairness in every country in which we operate;

* meeting sustainable development challenges by placing greater value on natural resources, protecting the environment, adapting our activities to the culture of the host country and engaging in dialogue with local communities; and

* cultivating and strengthening the relationships with our shareholders by providing regular and transparent information and communication.

ADGAS - Abu Dhabi Gas Liquifaction Company

To achieve our vision through the safe and efficient production, marketing, sale and delivery of LNG, LPG and natural gases, pentane and sulphur; building on our ADGAS history, solid partnerships and human capital.
We will strive to sustain our recognized international reputation for reliability, integrity and efficiency and to continually improve HSE and business performance. We will attract, develop and retain competent and dedicated staff ”.
We aim to do this by being a world class efficient and reliable company, through adhering to the highest Health, Safety, & Environment standards and through employees who are dedicated to Quality, Professionalism and Cost Effectiveness"