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The paper presents an outline of the CHEMDROP field experiment, carried out in November 1994 at the field station of S. Pietro Capofiume in the Po Valley, Italy. The main objective of the project was to address the issue of the size-dependent chemical composition of fog droplets, by experimentally investigating the following processes, which are expected to affect (or be affected by) the chemical
The new trace element measurement technique "photon-tagged Nuclear Reaction Analysis" (pNRA) is introduced and the experimental procedures are described in detail. The pNRA-technique is an ion-beam analytical technique intended for the determination of the abundance of the lightest elements, ranging from lithium to phosphorus. The technique is a complement to the PIXE technique. pNRA is a multipar
A new instrument for the study of cloud droplets and its relation to aerosol particles, the droplet aerosol analyser (DAA), was for the first time used in a field campaign. The DAA has the unique feature of measuring the ambient size of cloud droplets or cloud interstitial aerosol particles together with the size of its dry residue. This is obtained with a two-parameter data acquisition technique
A characterisation of the sources influencing the site for the final field campaign of the EUROTRAC subproject GCE (Ground-based Cloud Experiment) at Great Dun Fell, Cumbria, Great Britain in April-May 1993 is presented. The sources were characterised mainly by means of aerosol filter and cascade impactor data, single particle analysis, gas data, data on aromatic organic compounds, cloud water ion
The droplet activation process and droplet growth was studied during early stages of the formation of orographically-induced clouds. The experimental results were compared with the results obtained with a closed parcel, adiabatic cloud model. Good agreement was in most cases found between model and measurements with respect to cloud droplet number concentration, cloud droplet solute concentration
The size distributions and hygroscopic growth spectra of aerosol particles were measured during the GCE cloud experiment at Great Dun Fell in the Pennine Hills in northern England. Hygroscopic growth is defined as the particle diameter at 90% RH divided by the particle diameter at 10% RH. The fraction of the aerosol particles scavenged by cloud droplets as a function of particle size was also meas
A unipolar diffusion charger with minimal particle losses in the ultrafine size range has been developed. This charger uses two radioactive α-sources to produce ions which are drawn into the charging region by an alternating electric field. The aerosol flow in the centre of the charging region is surrounded by a particle-free sheath air flow to prevent particle losses. Charged aerosol particles mo
The cloud nucleation scavenging process was studied during a joint campaign of the EUROTRAC sub‐project Ground‐based Cloud Experiment. It was found that the particle size has a strong influence on the partitioning of particles between the cloud droplet and the interstitial aerosol reservoirs. A new aerosol sampling unit, the relative humidity processing system, was employed for the extraction of p
An example is given to show the possibility of using a multivariate statistical evaluation technique in order to extract more information from a multielemental PIXE data set. Four weeks of continuous sampling was carried out at a background air pollution monitoring station in Sweden. Samples were collected both in fine and coarse mode, with a cutoff at 2 μm. In the subsequent PIXE analysis of the
A schematic mechanistic box model presenting processes in atmospheric chemical cycles is used to present the main research objectives. From this the main use of PIXE within atmospheric chemistry is discussed. An analytic system giving molecular composition is necessary to fully understand and quantify the chemical and physical pathways described in the model for different compounds. Combining PIXE
This study investigates the relationship between super-fast broadband and firms’ sales and employment level in Sweden. It is important to learn more about this recent technological change and few studies has explored the impact of super-fast broadband on firm outcomes. We use the previous roll-out of second-generation internet access to identify the effect of third-generation internet access. The
The arch is a very efficient load bearing structure, especially when its shape is affine to the funicular of forces. However, if live loads are predominant as compared to permanent uniformly distributed gravity loads, the arch will be subjected to substantial bending moments, thus losing a great part of its structural efficiency. In traditional arch bridges with hangers arranged in a vertical mann
We argue that the human evolutionary heritage with frequent adaptations through geological time to environmental change has affected a trade-off between offspring variability and cancer resistance, and thus favored cancer-prone individuals. We turn the attention to a factor setting the highly cancer-resistant naked mole rat apart from most other mammals: it has remained phenotypically largely unch
Ion-beam thermography (IBT) is used to determine the chemical composition of atmospheric aerosols. The aerosols are analyZed by a combination of four ion-beam techniques PIXE, PESA, pNRA and cPESA during thermography. These techniques monitor the concentrations of the available elements during the stepwise heating of the sample. For each element a thermogram, i.e., the concentration vs. temperatur
The formation and development of orographic clouds was studied in a field experiment comprising several measurement sites at a mountain ridge. The influence of the aerosol population present on the cloud microstructure was studied in relation to the dynamics in the cloud formation. Droplet nucleation scavenging was investigated by the introduction of a non-dimensional particle diameter related to
