Cluster Density and the IMF

Observed variations in the IMF are reviewed with an emphasis on environmental density. The remote field IMF studied in the LMC by several authors is clearly steeper than most cluster IMFs, which have slopes close to the Salpeter value. Local field regions of star formation, like Taurus, may have relatively steep IMFs too. Very dense and massive clusters, like super star clusters, could have flatter IMFs, or inner-truncated IMFs. We propose that these variations are the result of three distinct processes during star formation that affect the mass function in different ways depending on mass range. At solar to intermediate stellar masses, gas processes involving thermal pressure and supersonic turbulence determine the basic scale for stellar mass, starting with the observed pre-stellar condensations, and they define the mass function from several tenths to several solar masses. Brown dwarfs require extraordinarily high pressures for fragmentation from the gas, and presumably form inside the pre-stellar condensations during mutual collisions, secondary fragmentations, or in disks. High mass stars form in excess of the numbers expected from pure turbulent fragmentation as pre-stellar condensations coalesce and accrete with an enhanced gravitational cross section. Variations in the interaction rate, interaction strength, and accretion rate among the primary fragments formed by turbulence lead to variations in the relative proportions of brown dwarfs, solar to intermediate mass stars, and high mass stars.Comment: 14 pages, 3 figures, to be published in ``IMF@50: A Fest-Colloquium in honor of Edwin E. Salpeter,'' held at Abbazia di Spineto, Siena, Italy, May 16-20, 2004. Kluwer Academic Publishers; edited by E. Corbelli, F. Palla, and H. Zinnecke

Vapor space characterization of waste Tank 241-U-106: Results from samples collected on March 7, 1995. Waste Tank Vapor Program

This report describes inorganic and organic analyses results from samples obtained from the headspace of the Hanford waste storage Tank 241-U-106 (referred to as Tank U-106). The results described here were obtained to support safety and toxicological evaluations. Quantitative results were obtained for the inorganic compounds ammonia (NH{sub 3}), nitrogen dioxide (NO{sub 2}), nitric oxide (NO), and water (H{sub 2}O) Sampling for hydrogen cyanide (HCN) and sulfur oxides (SO{sub x}) was not requested. The NH{sub 3} concentration was 16% greater than that determined from an ISS sample obtained in August 1994; the H{sub 2}O concentration was about 10% less. In addition, quantitative results were obtained for the 39 TO-14 compounds plus an additional 14 analytes. Of these, 5 were observed in two or more canisters above the 5-ppbv reporting cutoff. Eleven organic tentatively identified compounds (TICS) were observed in two or more canisters above the reporting cutoff of (ca.) 10 ppbv and are reported with concentrations that are semiquantitative estimates based on internal-standard response factors. The 10 organic analytes with the highest estimated concentrations account for approximately 90% of the total organic components in Tank U-106. Three permanent gases, nitrous oxide (N{sub 2}O), hydrogen (H{sub 2}) and carbon dioxide (COD were also detected

Vapor space characterization of waste Tank 241-BY-111: Results from samples collected on November 15, 1994

This report describes results of the analyses of tank-headspace samples taken from the Hanford waste Tank 241-BY-111 (referred to as Tank By-111). Pacific Northwest Laboratory (PNL) contracted with Westinghouse Hanford company (WHC) to provide sampling devices and to analyze inorganic and organic analytes collected from the tank headspace and ambient air near the tank. The target analytes for TO- 14 compounds were extended to include 14 analytes identified by the Toxicological Review Panel for Tank C-103 and reported by Mahlum et al. (1994). Program management included these analytes for future tank analyses as identified in the fiscal year work plan. This plan is attached to a letter dated 9/30/94 and addressed to Mr. T.J. Kelly of WHC. The plan also requires PNL to analyze for the permanent gases as shown in Table 3.7. The sample job was designated S4083, and samples wee collected by WHC on November 16, 1994, using the vapor sampling system (VSS). The results of the analyses are expected to be used to estimate the potential toxicity of tank-headspace gas as described in Data Quality Objectives for Generic In-Tank Health and Safety Vapor Issue Resolution, WHC-SD-WM-DQO-002, Rev. 0

Waste Tank Vapor Program: Vapor space characterization of Waste Tank 241-T-107. Results from samples collected on January 18, 1995

This report describes inorganic and organic analyses results from samples obtained from the headspace of the Hanford waste storage Tank 241-T-107 (referred to as Tank T-107). The results described here were obtained to support safety and toxicological evaluations. A summary of the results for inorganic and organic analytes is listed in Table 1. Detailed descriptions of the results appear in the text. Quantitative results were obtained for the inorganic compounds ammonia (NH{sub 3}), nitrogen dioxide (NO{sub 2}), nitric oxide (NO), and water (H{sub 2}O). Sampling for hydrogen cyanide (HCN) and sulfur oxides (SO{sub x}) was not requested. In addition, quantitative results were obtained for the 39 TO-14 compounds plus an additional 14 analytes. Of these, I was observed above the 5-ppbv reporting cutoff. Six organic tentatively identified compounds (TICs) were observed above the reporting cutoff of (ca.) 10 ppbv and are reported with concentrations that are semiquantitative estimates based on internal-standard response factors. The estimated concentration of all 7 organic analytes observed in the tank headspace are listed in Table I and account for approximately 100% of the total organic components in Tank T-107. Two permanent gases, carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O), were also detected in the tank-headspace samples

Development and validation of a preparation and cleanup method for hydrocarbon containing samples for the analysis of volatile organic compounds

Samples obtained from the Hanford single shell tanks are contaminated with normal paraffin hydrocarbon (NPH) as hydrostatic fluid from the sampling process or can be native to the tank waste. The contamination is usually high enough that a dilution of up to several orders of magnitude may be required before the sample can be analyzed by the conventional purge and trap concentration followed by gas chromatography/mass spectrometry methodology. This can prevent detection and measurement of organic constituents that are present at lower concentration levels. To eliminate or minimize the problem, a sample cleanup method has been developed and validated and is presented in this document

Zukunft der Arbeit und Arbeit der Zukunft in Deutschland

Due to the fact that the unemployment rate of high skilled labour in Germany is about 3% in the last 30 years, this paper deals with theories that account for heterogeneous labour. The main finding is that the reduction of the labour costs cannot reduce the aggregated unemployment rate substantially. An important conclusion is that the skill upgrading of the labour force is slower than that of labour demand. The future of work in Germany lies not in low paid low skilled jobs, but in high(er) skilled occupation. Copyright Verein für Socialpolitik und Blackwell Publishers Ltd, 2006