Retardation devices

Delay Release Assembly. An item which releases a retardant device on a bomb, to reduce the velocity of the bomb in flight. 

Two special retardation devices find wide application in the design of optical po-larimeters. These are the quarter-wave plate with 8 = jc/2 and the half wave plate with 8 = re. The utility of a quarter-wave plate can be demonstrated by observing its effect on... 

An important use of bromine compounds is in the production of flame retardants (qv). These are of the additive-type, which is physically blended into polymers, and the reactive-type, which chemically reacts during the formation of the polymer. Bromine compounds are also used in fire extinguishers. Brominated polymers are used in flame retardant appHcations and bromine-containing epoxy sealants are used in semiconductor devices (see... 

In an electrooptic material the phase retardation angle is controlled by altering birefringence, which is in turn controlled by the potential of an apphed electric field. An electrooptic device thus acts as a variable phase optical retardation plate, and can be used to modulate the wavelength or intensity of an incident beam. 

Automated soldering operations can subject the mol ding to considerable heating, and adequate heat deflection characteristics ate an important property of the plastics that ate used. Flame retardants (qv) also ate often incorporated as additives. When service is to be in a humid environment, it is important that plastics having low moisture absorbance be used. Mol ding precision and dimensional stabiUty, which requites low linear coefficients of thermal expansion and high modulus values, ate key parameters in high density fine-pitch interconnect devices. 

Transmitter/Actuator Networks With the advent of smart transmitters and smart actuators, the limitations of the 4-20 milliamp analog signal transmission retard the full utilization of the capabilities of the smart devices. For smart transmitters, the following capabilities are required ... 

One of the most stringent and most widely accepted test is UL 94 that concerns electrical devices. This test, which involves burning a specimen, is the one used for most flame-retardant plastics. In this test the best rating is UL 94 V-0, which identifies a flame with a duration of 0 to 5 s, an afterglow of 0 to 25 s, and the presence of no flaming drips to ignite a sample of dry, absorbent cotton located below the specimen. Tlie ratings go from V-0, V-l, V-2, and V-5 to HB, based on specific specimen thicknesses. 

To solve the measurement problem and obtain quantitative results (retardation, magnitude of the residual strain, etc.), various techniques are used. An example is using a very simple device known as a wedge compensator (ASTM D 4093). It is placed between the... 

Worldwide consumption of performance additives (excluding plasticisers) grew from just over 2.7 mt in 1996 to 3.6 mt in 2001. Flame retardants make up 31 % of the volume and stabilisers, impact modifiers and lubricants each account for around 16-17%. Flame retardant markets (construction, E E devices, automotive) are headed for unprecedented development and change, being threatened by environmental, health... 

Generally, silyl substituents seem to retard the hole-transporting ability of PPV. As a result, devices fabricated from silyl-substituted PPVs suffer from a high turn-on voltage. To improve the EL efficiency of PLEDs fabricated from Si-PPVs, the introduction of additional hole injection layer or copolymerization with electron-rich comonomers is required. 

Goodwin, M. J. and Gillham, R. W., 1982, Two Devices for in Situ Measurements of Geotechnical Retardation Factors In Proceedings of the Second International Hydro-geological Conference (edited by G. Ozoray), International Association of Hydrogeologists, Canadian National Chapter, pp. 91-98. 

Mechanically operated screens are vibrated by means of an electromagnetic device as shown in Figure 1.40, or mechanically as shown in Figure 1.41. In the former case the screen itself is vibrated, and in the latter, the whole assembly. Because very rapid accelerations and retardations are produced, the power consumption and the wear on the bearings are high. These screens are sometimes mounted in a multi-deck fashion with... 

The principle of operation of this device is simple. A small amount of the flowing water volumetrically displaces foam concentrate from the tank into the main water stream. The working pressure of the vessel must, of course, be above the maximum static water pressure encountered in the system. This type of proportioner may consist of one tank or pressure container with a watertight divider so that it operates as two tanks, two tanks separately connected to the water and foam solution lines, or the tanks in the system may each be fitted with flexible diaphragms or bladders to separate the "driving" water from foam concentrate or they may rely simply on differences in density of the two liquids to retard mixing during operation. 

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