Stockholm University

About: Stockholm University is a education organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Supernova. The organization has 21052 authors who have published 62567 publications receiving 2725859 citations. The organization is also known as: University of Stockholm & Stockholms universitet.

Flame retardants in indoor air at an electronics recycling plant and at other work environments.

Abstract: Air samples from a plant engaged in recycling electronics goods, a factory assembling printed circuit boards, a computer repair facility, offices equipped with computers, and outdoor air have been analyzed with respect to their content of brominated hydrocarbon and phosphate ester flame retardants. Polybrominated diphenyl ethers, polybrominated biphenyls, 1,2-bis(2,4,6-tribromophenoxy)-ethane, tetrabromobisphenol A, and organophosphate esters were all detected in the indoor air samples, with the highest concentrations being detected in air from the recycling plant. In air from the dismantling hall at the recycling plant the average concentrations of decabromodiphenyl ether, tetrabromobisphenol A, and triphenyl phosphate were 38, 55, and 58 pmol/m3, respectively. Significantly higher levels of all of these additives were present in air in the vicinity of the shredder at the dismantling plant. This is the first time that 1,2-bis(2,4,6-tribromophenoxy)-ethane and several arylated phosphate esters are reported to be contaminants of air in occupational settings. At all of the other sites investigated, low levels of flame retardants were detected in the indoor air. Flame retardants associated with airborne particles, present at elevated levels, pose a potential health hazard to the exposed workers.

A parameterization scheme for non-convective condensation including prediction of cloud water content

Abstract: A model for non-convective condensation processes has been developed. The model allows condensation to begin before relative humidity reaches 100%. The liquid water content of clouds is a prognostic variable of the model. The rate of condensation is a function of relative humidity and moisture flux convergence. The micro-physical processes involved in the formation of clouds and precipitation are parameterized by assuming that the rate of precipitation formation is a function of the amount of cloud water. Evaporation from falling rain is taken into account. Quantitative tests with the model indicated that it yields reasonable evolution times and water content of clouds, and gives reasonable precipitation amounts.

Factors controlling the acidity of natural rainwater

Abstract: It is often assumed1–4 that the pH of natural rainwater is controlled by the dissociation of dissolved CO2, has a value of 5.6, and that decreases below this are due to the addition of acidic components by human activity. However, decreases could be due to the removal by rainwater of naturally occurring acids from the air (notably H2SO4 in the natural portion of the sulphur cycle). Consideration of the cycling of water and sulphate through the atmosphere and the amount and composition of sulphate aerosol expected to be scavenged by a given amount of cloud water in remote locations indicates that, in the absence of basic materials (such as NH3 and CaCO3), average pH values of ∼5 are expected to occur in pristine locations. This value must vary considerably due to variability in scavenging efficiencies as well as geographical patchiness of the sulphur, nitrogen and water cycles. Thus, pH values might range from 4.5 to 5.6 due to variability of the sulphur cycle alone. Because of widespread concern regarding the acidification of rain, it is important to understand the factors controlling the pH and composition of natural rainwater. We suggest here that there are integral constraints imposed by (1) the requirement for mass continuity in each elemental cycle and (2) the relative concentrations of soluble species and liquid water in cloudy air; these factors must be mutually consistent.

Electron performance measurements with the ATLAS detector using the 2010 LHC proton-proton collision data

Abstract: Detailed measurements of the electron performance of the ATLAS detector at the LHC are reported, using decays of the Z, W and J/psi particles. Data collected in 2010 at root s = 7 TeV are used, corresponding to an integrated luminosity of almost 40 pb(-1). The inter-alignment of the inner detector and the electromagnetic calorimeter, the determination of the electron energy scale and resolution, and the performance in terms of response uniformity and linearity are discussed. The electron identification, reconstruction and trigger efficiencies, as well as the charge misidentification probability, are also presented.