introduction: hydrogen fluoride is one of the materials which is widely used in making glass, cleaning  silicon, manufacturing florescent lamps, ceramics and also in separating uranium isotopes. on the other hand, exposure to this substance could cause health problems including eye, nose, throat and mucus membranes irritation. this study examines the relationship between fluoride (f) in the uri...

Steam-water flow exists in most geothermal reservoirs where steam-water capillary pressure plays an important role in controlling fluid distribution, transfer of liquid between fracture and matrix, well productivity, and even the reserves. However, it is very difficult to measure steam-water capillary pressure due to the phase transformation and the significant mass transfer between the two pha...

In April 1995, the US Geological Survey began a study to determine the occurrence and temporal distribution of 49 pesticides and pesticide metabolites in air and rain samples from an urban and an agricultural sampling site in Mississippi. The study was a joint effort between the National Water-Quality Assessment and the Toxic Substances Programs and was part of a larger study examining the occu...

Water/air, blood/air, oil/air, oil/water, and oil/blood partition (or solubility) coefficients of 17 aromatic hydrocarbons and ketones were measured by a newly developed vial-equilibration method, which needs no direct measurements of the concentration either in the liquid or in the air phase, but only the gas chromatographic peak heights of the air in the sample (in which a test material is co...

The synthesis of micro-sized, uniformly distributed Al2O3-15Vol% Ni powders were studied through three step co-precipitation of hydroxides mixtures from proper solution, calcination at air atmosphere and final step of calcined powders in a carbon bed. Al and Ni hydroxide and amorphous phase were first obtained from their salt’s solutions through chemical co-precipitation method by adjusti...

In April 1995, the U.S. Geological Survey began a study to determine the occurrence and temporal distribution of 49 pesticides and pesticide metabolites in air and rain samples from an urban and an agricultural sampling site in Mississippi. The study was a joint effort between the National WaterQuality Assessment and the Toxics Substances Programs and was part of a larger study examining the oc...

Effects of sample storage methods on the quantity and quality of labile soil organic carbon are not fully understood even though their effects on basic soil properties have been extensively studied. We studied the effects of air-drying and frozen storage on cold and hot water soluble organic carbon (WSOC). Cold- and hot-WSOC in air-dried and frozen-stored soils were linearly correlated with tho...

A new method for sampling and chemical analysis of alphacypermethrin in workplace air has been described. Air samples were taken using a glass tube filled with silica gel with chemically bounded octadecyl phase. Chromatographic determinations were conducted using an HP-5 capillary column (10 m x 0.53 mm) and an electron-capture detector. Alphacypermethrin recovery was 100.15%. The calculated de...