Resistive element

Incandescent Lamps, Electronic Tubes, and Resistance Elements. Articles fashioned in any form from molybdenum and tungsten usually fall within the bounds of powder metallurgy. These metals normally are first produced as a powder. Both molybdenum and tungsten are used as targets in x-ray tubes, for stmctural shapes such as lead and grid wires in electron tubes, and as resistance elements in furnaces. 

Vitreous silica is used for gas-heated or electrically heated devices ia various shapes, eg, as a tube or muffle because of its electrical resistivity, impermeabihty, and low expansion. In its simplest form, an electric-resistance furnace consists of a vitreous siUca tube or pipe on which the resistance element is wound (see Furnaces, ELECTRIC). Because of its iadifference to temperature gradients, a tubular furnace of vitreous siUca maybe made to operate at different temperatures at various portions of the tube, either by arrangement of the heating elements or by cooling sections of the tube with water. Vitreous siUca pipes may be employed ia vacuum-iaduction and gas-fired furnaces (see Vacuum technology) (221). 

Siace the early 1970s, development work has been reported on thick-film, thin-film, and other resistance elements which are made by deposition rather than wound from wine. Such thermometers might have certain advantages of size, response time, cost, etc. These do not have the stabiUty or iaterchangeabihty of wrought-wke elements. 

The power dissipated in an AC circuit with only resistive elements is... 

Winter heating items fitted within room air-conditioners may be electric resistance elements, hot water or steam coils, or reverse cycle (heat pump). One model of water-cooled unit operates with a condenser water temperature high enough to be used also in the heating coil. 

Hot-Wall Reactors. A hot-wall reactor is essentially an isothermal furnace, which is often heated by resistance elements. The parts to be coated are loaded in the reactor, the temperature is raised to the desired level, and the reaction gases are introduced. Figure 5.6 shows such a furnace which is used for the coating of cutting tools with TiC, TiN, and Ti(CN). These materials can be deposited alternatively under precisely controlled conditions. Such reactors are often large and the coating of hundreds of parts in one operation is possible (see Ch. 18). 

P-gp is expressed in tumor tissue and serves as a barrier to increased accumulation of cytotoxic anticancer drugs within the cancer cell by actively pumping the drug out of the cell. It is a multidrug resistance element by virtue of the fact that it is promiscuous in terms of substrate selectivity. It, like the cytochromes P450, will accept a wide diversity of structural types. For example, a small sampling of drugs that are substrates for P-gp... 

A number of studies were done in order to determine which of these various factors contribute to the large peak separations observed here. First, it is well known that the effects of resistive elements can be obviated by applying positive feedback [132]. When positive feedback was applied to a thin-film confrol elecfrode similar fo fhaf described in Fig. 27, the peak separation decreased from 0.8 to —0.35 V (Fig. 28). These data show that resistance does, indeed, contribute to the large AEp values observed here. However, the fact that —0.35 V of this peak splitting cannot be removed by applying positive feedback clearly indicates that slow electron transfer kinetics also contribute to AEp. ... 

These selected studies demonstrate that carefully designed aminoglycosides can maintain antibiotic activity despite the presence of resistance elements that would inactivate compounds in current clinical use. 

In practice, poor charge mobility, energetic disorder, carrier trapping, and physical aberrations comphcate device characterization. The effects of these nonidealities are often modeled according to an equivalent circuit shown in Fig. 12. Incorporating all specific series resistive elements as R, and all specific parallel resistances as R, one obtains the expression... 

Simonsen G.S., H. Haaheim, K.H. Dahl, H. Kruse, A. Lovseth, O. Olsvik, and A. Sundsfjord (1998). Transmisssion of vanA-type vancomycin-resistant enterococci and vanA resistance elements between chicken and humans at avoparcin-exposed farms. Microbial Drug Resistance—Mechanisms Epidemiology and Disease 4 313-318. 

A method for continuous determination of ionization wave propagation was developed (See Refs 9 11)- Basically the system uses a linear resistance element that is imbedded in the chge and usually positioned on the axis where chge symmetry will provide interactions of the greatest magnitude. In its... 

Later in the research, a variation of the resistance element technique was developed to permit the continuous measurement of a compression wave position with respect to time. With this modification the compression wave movement, during the period prior to establishment of an exothermal reaction, could be studied. The pressure-actuated resistance probe consists of a thin-walled me-... 

HPDB propint, deton ceased in the 1.25 cm diam segment (as indicated by arrow) but readily propagated thruout the next larger segment of 1.7 cm. Two typical resistance element records are shown in Figs 14 and 15 of the Rept. Fig 14 is reproduced here as Fig 2 without oscillogram. The steady-state rate was 6.5 mm/microsec... 

In 1967, Massmann described a heated graphite furnace in which no auxiliary electrode was used, i.e. the graphite tube was both the resistance element and the furnace. The sample was micro-pipetted directly into a 55 mm long, 6.5 mm internal diameter, 1.5 mm wall thickness tube via a small 2 mm diameter orifice. The absorption tube device and a graphite... 

To obtain a gas sensitive continuum we used a special technique for sensor manufacturing, which allowed formation of a mesoscopic point-contact multistructure of TCNQ salts (Fig. 7.1). This structure is a set of a large number of resistant elements, namely point contacts [23], formed in the points of touching of the lateral... 

The air bath may be either a flame or electrically heated metal casting (Note 2), or an electric-resistance element (Note 3)... 

Foreign DNA is ligated to cleaved pBR322. Where ligation is successful, the ampicillin-resistance element is disrupted. The tetracycline-resistance element remains intact. 

Bacteria have two classes of transposons. Insertion sequences (simple transposons) contain only the sequences required for transposition and the genes for proteins (transposases) that promote the process. Complex transposons contain one or more genes in addition to those needed for transposition. These extra genes might, for example, confer resistance to antibiotics and thus enhance the survival chances of the host cell. The spread of antibiotic-resistance elements among disease-causing bacterial populations that is rendering some antibiotics ineffectual (pp. 925-926) is mediated in part by transposition. 

Resistance element, e.g. man-ganin 2) 0-30 1 in 103 0.1 (depends on pressure) Probably the mostly used secondary gauge for the range 10-30 kbar... 

Thermistor bead element. A thermal conductivity detection device in which a small glass-coated semiconductor sphere is used as the variable resistive element in the cell chamber. 

FILAMENT. The resistive element (I) in a common electric lamp and (2) in a thermionic tube through which current is passed to provide the temperature required for thermionic emission. The surface of the filament may supply the emission, or the filament may be employed as a heater for an indirectly heated cathode. 

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