Resistivities factors affecting

Moderate insulators with lower resistivity and higher dielectric constant and power factor affected further by the conditions of the test. These materials are often referred to as polar polymers. 

FIGURE 38 Lead coffin. Lead coffin (first—third centuries c.E.) from Jerusalem, Israel. Lead, widely used in many ancient civilizations, was one of the first metals to be recovered from its ores. Lead objects date back from as early as the seventh century b.c.e. In Mesopotamia molten lead was used to fasten bolts and shafts into masonry. In Syria it was made into rods used as currency, and in Greece it was cast into coins. During the Roman Empire the use of lead become so widespread that the health hazards caused by lead exposure are suspected to have been one of the factors affecting the fall of the Roman Empire. Since it is very resistant to corrosion, lead was also used by the Romans, for making coffins as the one illustrated. 

Kagawa and Toyama in Tokyo followed 20 normal 11-yr-old school children once a week from June to December 1972 with a battery of pulmonary-function tests. Environmental factors studied included oxidant, ozone, hydrocarbon, nitric oxide, nitrogen dioxide, sulfur dioxide, particles, temperature, and relative humidity. Temperature was found to be the most important environmental factor affecting respiratory tests. The observers noted that pulmonary-function tests of the upper airway were more susceptible to increased temperature than those of the lower airway. Although the effect of temperature was the most marked, ozone concentration was significantly associated with airway resistance and specific airway conductance. Increased ozone concentrations usually occur at the same time as increased temperature, so their relative contributions could not be determined. 

These results have suggested that mineral dusts that are inert in a particulate form may have biological activity when they occur in a fibrous form. Factors affecting fiber toxicity include length, diameter, respirability resistance to chemical dissolution in biological fluids, and durability. "... 

If a plant deters feeding by an Insect, the mechanism of resistance may be classified as antlxenosls or antibiosis. The critical question is whether the Insect is completely prevented from feeding, thus starving to death (antibiosis), or would eventually feed on that plant when given no choice (antlxenosls). Since the answers to such questions are not always known, this discussion will deal with the factors affecting an insect s behavior in the selection of a host plant, with emphasis on behavior. 

Harvey F. A., McGee E. N., 1952, Factors affecting resistance of silica refractories to abrasion, J. Am. Ceram. Soc., 895. 

Factors Affecting Performance. The flame resistance of a textile fiber is affected by the chemical nature of the fiber, its ease of combustion, the fabric weight and construction, the efficiency of the flame retardant, the environment, and laundering conditions. 

Sullivan, J.T. and Spence, J.V. (1 999) Factors affecting adoptive transfer of resistance to Schistosoma mansoni in the snail intermediate host, Biomphalaria glabrata. journal of Parasitology 85, 1 065-1 071. 

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