Additivity of State Inventories of Greenhouse-Gas Emissions

In addition to national inventories of emissions of greenhouse gases, there are inventories for most, but not all, states constituting the United States. This paper analyzes the state inventories to see if reported emissions of carbon dioxide, methane, and nitrous oxide are additive. Considerable reanalysis of the state inventories is required before they can be added to yield a larger-scale inventory. Some specific sources were considered by some states but not by others. Estimation techniques evolved over time as inventories were produced, and there are instances of both double-counting (two states reporting the same emission) and omission (neither state reporting the same emission), where interstate transfers of energy or materials occurred. Nevertheless, the inventories, when adjusted for obvious double-counting or omissions, are probably approximately additive, although it is difficult to quantify the extent to which this is true.     

Worldwide Availability of Silver

This article summarizes and interprets estimates, by the US Bureau of Mines and others, of the availability of silver from primary and secondary sources in market economy countries. Despite conservative measurements, ample silver to support expansion of its use in industrial applications was found to exist. Supply from only portions of this resource base can be expected to respond to changes in silver demand, because factors other than price are the major determinant of the flow of silver from large segments of its resource base.     

Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4 +-N). In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at di erent carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30°C, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine (NH2OH), nitrite (NO2??) and nitrate (NO3??) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.