We report on the ion emission from impacts of hypervelocity massive gold clusters for use in secondary ion mass spectrometry. Two massive gold clusters are considered, 520 keV Au 400 4+ and 1040 keV Au 2800 8+ . The emission of fragment ions and molecular ions is evaluated for a series of neat samples, glycine, phenylalanine, arginine, and gramicidin S. A 2 to 4-fold increase of molecular ion emission is observed from impacts of 1040 keV Au 2800 8+ versus 520 keV Au 400 4+ . Compared to impacts of 20 keV Ar 2000

No abstract

Copper contamination of drinking water and marine areas is detrimental to human health and the environment. Physical and chemical approaches currently used for copper removal from water tend to be expensive and may introduce chemicals to the water. Using suspended algae to remove copper is a biological approach. Its cost is relatively low, and algae can be used for other purposes after being used for copper removal. However, this approach using algae is currently limited in its usefulness due to technological barriers. For example, chemical agents used to remove suspended algae from water after copper is absorbed, can cause secondary contamination. Using immobilized algae instead of suspended algae can overcome these problems. In this preliminary study, hydrogel filters containing algae cells and those containing no algae cells are printed on an extrusion-based 3D printer. They were used in a custom-build filtration setup for copper removal. Experimental results show that hydrogel filters containing algae cells reduced copper concentration in the test solution by about 83% (from 3 to 0.5 ppm) after one hour of filtration, while hydrogel filters containing no algae cells reduced copper concentration in the test solution by about 50% (from 3 to 1.5 ppm) after one hour of filtration.

No abstract

Element Concentrations). These materials have been used worldwide for quality assurance by a variety of laboratories involved in the determination of major, minor, and trace element content of soils and similar materials. Stocks of these original SRMs were depleted by 2008, and replacement SRMs were produced which became available in 2009. This paper describes, in detail, the process for the renewal of these three soil SRMs including soil collection and preparation methods, homogeneity assessment, experimental design, and the element analysis and data evaluation methods used to provide certified, reference, and information mass fraction values for 44 to 48 major, minor, and trace element constituents. For each SRM, the acid-extractable amount content of selected elements was determined by participants in the US Environmental Protection Agency's Contract Laboratory Program, and summaries of those method-specific results are included as addenda to the Certificates of Analysis.