Tests electrical stability

Electrical Stability of Emuisions. The electrical stability test indicates the stability of emulsions of water in oil. The emulsion tester consists of a reliable circuit using a source of variable AC current (or DC current in portable units) connected to strip electrodes. The voltage imposed across the electrodes can be increased until a predetermined amount of current flows through the mud emulsion-breakdown point. Relative stability is indicated as the voltage at the breakdown point. 

Electrical stability The test measures the voltage required to cause current flow between two electrodes immersed in an oil-base mud. The higher the voltage, the greater the stability and, consequently, the greater the drillpipe protection (see API RP 13B for more details [206]). 

Silver iodide particles in aqueous suspension are in equilibrium with a saturated solution of which the solubility product, aAg+ai, is about 10 16 at room temperature. With excess 1 ions, the silver iodide particles are negatively charged and with sufficient excess Ag+ ions, they are positively charged. The zero point of charge is not at pAg 8 but is displaced to pAg 5.5 (pi 10.5), because the smaller and more mobile Ag+ ions are held less strongly than-the 1 ions in the silver iodide crystal lattice. The silver and iodide ions are referred to as potential-determining ions, since their concentrations determine the electric potential at the particle surface. Silver iodide sols have been used extensively for testing electric double layer and colloid stability theories. 

The test for stability (gas evolution) under electric stress must not be confused with tests for the gas content of insulating oil (ASTM D-831, ASTM D-1827, ASTM D-2945). These tests are largely factory control tests to ensure that oils intended for filling equipment have been adequately degassed (because dissolved gas, like gas evolved under stress, could cause void formation). 

To test the electrical stability of the Cu-Zn alloy and Cu on silicon oxide, a 50nm gate oxide with an A1 back contact on p-substrate was prepared. By sputtering through a shadow mask, metal oxide semiconductor (MOS) dots of 1.2mm diameter were developed. The specimens were annealed at different temperatures and tested for bias temperature stability. 

The test methods covered in this chapter are those most closely related to adhesives for die and substrate attachment, surface-mounting of components, underfill, and optoelectronic assembly. Some tests, such as bleedout and electrical stability, for which there are no standard test methods, are not covered but information for these procedures was already addressed in other portions of this book, for example, in Sections 2.1 and 6.1. 

The main electrical properties related to organic materials are volume resistivity (for both conductive and nonconductive adhesives) and dielectric constant and dissipation factor (for insulative materials). Other electrical tests for conductive materials that are more application specific are electrical stability, current-carrying capacity, and interconnect resistance. 

Electrical-stability testing is essential for conductive adhesives used for electrical connections. Electrical conductivity can degrade at elevated temperatures, on aging with or without power, and on exposiue to humidity and temperature. The specific test method used depends on the application. One test used for die-attach adhesives specified in NASA MSFC-SPEC-592 (now inactive) involves a series of gold-plated Kovar tabs attached with conductive epoxy to metal pads on an interconnect substrate. In the test vehicle, a bias of 5 V and cmrent density of 139 3.9 A7cm (900 A/in ) are applied to a series of wire-connected tabs, and the resistance change is measured after exposure to 150 °C periodically up to 1,000 horns. The maximum allowable resistance change is 5%. 

The optical power stability poses a major problem for practical photonic applications. In order to test the stability of the device, we did three different stability tests. There are several drifts due to an applied electric field, an external light, and the guiding laser itself. 

In addition to the dielectric-strength test at power frequency, which remains the basic test, other criteria have been adopted, such as impulse breakdown voltage, partial-discharge voltage and electrical stability under partial discharges as characterized by gassing. 

The statistically non-centrosymmetric polar order of the chromophore units reached during the poling procedure is thermodynamically stable only with the electric field on. Once cooled down at room temperature and switched off the field, that polar order becomes metastable and it will relax to the more stable centrosymmetric arrangement, which is not NLO active. So, an other fundamental issue is to reach an high time stability of the polar order. Industrial standards for device testing require stability of NLO performances for 10 years at 85°C, that are quite severe. 

A very common way of testing emulsion stability is to age samples at various temperatures and to monitor parameters such as apparent viscosity, percentage of phase separation, particle size, zeta-potential, rheological parameters, electrical conductivity, and so forth. 

Electrokinetics. Electrokinetics is a tested technology that has been used for over half a century to dewater and stabilize soils, and has recently been investigated for in situ use at hazardous waste sites (23). Primarily used for metals removal, the technology utilizes an electrical field to generate a flow and concentration gradient in porous and semiporous soils. 

Cathodic protection cannot work with prestressed concrete structures that have electrically insulated, coated pipes. There is positive experience in the case of a direct connection without coated pipes this is protection of buried prestressed concrete pipelines by zinc anodes [38], Stability against H-induced stress corrosion in high-strength steels with impressed current has to be tested (see Section 2.3.4). 

The first experiments with the thermal electric engine were conducted in Russia in 1929 by its inventor, Valentin P. Glushko, who later became a world-famous authority in rocket propulsion. For more than forty years, the United States and Russia have devoted many resources to research and development of various kinds of EREs. First tested in space by the Russians in 1964, these engines have found some limited applications in modern space technology. For more than two decades Russian weather and communication satellites have regularly used electric rocket engines for orbital stabilization. The first spacecraft to employ ERE for main propulsion was the American asteroid exploration probe Deep Space 1, launched in 1998. The performance of... 

The moisture content of a plastic affects such conditions as electrical insulation resistance, dielectric losses, mechanical properties, dimensions, and appearances. The effect on the properties due to moisture content depends largely on the type of exposure (by immersion in water or by exposure to high humidity), the shape of the product, and the inherent behavior properties of the plastic material. The ultimate proof for tolerance of moisture in a product has to be a product test under extreme conditions of usage in which critical dimensions and needed properties are verified. Plastics with very low water-moisture absorption rates tend to have better dimensional stability. 

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