Atmospheric conditions, surveying

Human Exposure. The threshold of perception of ammonia varies from person to person and may also be influenced by atmospheric conditions, values as low as 0.4-2 mg/m3 (0.5-3 ppm) are reported in [1374], but 50 ppm may easily detected by everybody [1375]. Surveys [1376] found concentrations from 9-45 ppm in various... 

Solid catalysts for the metathesis reaction are mainly transition metal oxides, carbonyls, or sulfides deposited on high surface area supports (oxides and phosphates). After activation, a wide variety of solid catalysts is effective, for the metathesis of alkenes. Table I (1, 34 38) gives a survey of the more efficient catalysts which have been reported to convert propene into ethene and linear butenes. The most active ones contain rhenium, molybdenum, or tungsten. An outstanding catalyst is rhenium oxide on alumina, which is active under very mild conditions, viz. room temperature and atmospheric pressure, yielding exclusively the primary metathesis products. 

Mapping the GSC survey data for Hg concentrations in stream sediments in terms of local flow-channel and upland/lowland patterns provides a new means to evaluate these data in relation to local geologic and topographic conditions and configurations. Overlaying other geo-referenced data layers such as climate and atmospheric deposition maps including Hg deposition will reveal additional association-patterns between Hg in stream sediments and surrounding factors. 

Atmospheric visibility is a property valued by many people, as has been shown in consumer surveys, in addition to affecting transportation safety and the amount of solar energy reaching the ground. In the East, visibility can be reduced to 5 km or less under hazy, humid conditions (25). In the arid west, it can exceed 200 km under ideal conditions. 

Under the conditions of the reduction of regional hydrographic measurements and surveys on the entire sea scale, the study of the interannual SST variability may be based only on the regular and permanently replenished information with a high spatio-temporal resolution. Such satellite information about the SST is acquired by the measurements with Advanced Very High Resolution Radiometers (AVHRR) onboard the satellites of the National Oceanic and Atmospheric Administration (NOAA). The efficiency of the use of these satellite data for the studies of the spatio-temporal variability of the Black Sea temperature regime was demonstrated in [8-13]. 

Monitoring of changes in the radioecological situation around each radiation-hazardous enterprise is the main methodic principle of information survey. Measurements, which frequency and scope depend on location and specific condition of every environmental contamination source, are conducted as follows monitoring of seawater, aerosols - every day dry land, atmospheric depositions - every week drinking water - every month coastal and marine vegetation, fish, benthos - once a year. 

The surface properties of various phases corresponding to the same chemical formula can substantially differ from one crystallographic form to another. This is well known, and the information about the crystallographic form of the adsorbents is specified in many publications on adsorption, especially when the compound of interest forms more than one phase showing a sufficient stability at the experimental conditions. Since the present survey is devoted to adsorption studies performed at room temperatme and atmospheric pressure the phases existing only at very high pressures or at very high (or very low) temperatures are not considered. 

Further support for the importance of variable oxidation state of the metal oxide is provided by titanium and vanadium oxide additive studies on MgH2. In a study of Mg-20 wt% rutile Ti02 prepared by RMA in a H2 atmosphere, it was found that complete H2 desorption occurred in 9 min at 350 °C in 0.1 MPa H2 (Wang et al, 2000). In the survey of a range of oxide materials by Oelerich et al. (2001), a 0.03 wt% Ti02 addition to ball milled MgH2 for 20h resulted in a material which took only 7 min for complete desorption at 573 K in vacuum, while 0.06 wt% V2O5 addition under the same conditions showed complete desorption in 5 min which is also an oxide of a multivalent metal. 

The purpose of this review paper is to survey the principles of high temperature oxidation or high temperature corrosion. A typical situation is that of a metal exposed to a hot gas which can act as an oxidant. In many cases the oxidation product forms a layer which separates the reactants, the metal and the gas atmosphere. Under special conditions, the kinetics are diffusion controlled, i. e,, the rate of the reaction (the rate of oxide thickness growth) depends on the diffusion of species, ions and electrons, through the layer (sometimes called a tarnish layer). Actually when a metal or alloy is exposed to a corrosive gas, the reaction kinetics may be controlled by one or more of the following steps ... 

Some of the discrepancies between the Wiepking-Doyle data and the Soden-McLeish data may have been systematic. The Wiepking-Doyle (linear) results were based on a sample population that uniformly had a 12 percent moisture content. The Soden-McLeish (exponential) results,however, were derived in part from the Doyle et al. work based on samples with 9.5 percent moisture content, and in part on their own experiments for which no moisture contents were reported. It is difficult to tell whether these variations in percent moisture could have biased the results significantly. No moisture-related effects on the properties of balsa wood have been evaluated explicitly in any of the literature references surveyed here. To the extent that moisture contents were reported at all, they ranged generally from 8 to 12 percent. This range appears to be a normal condition for kiln-dried balsa wood exposed to ambient atmosphere in temperate climates. (Note The ASTM Standard Method of Testing Small Clear Specimens of... 

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