Intercomparison Study of Six HTDMAs: Results and Recommendations

We report on an intercomparison of six different hygroscopicity tandem differential mobility analysers (HTDMAs). These HTDMAs are used worldwide in laboratory experiments and field campaigns to measure the water uptake of aerosol particles and have never been intercompared. After an investigation of the different design of the instruments with their advantages and inconveniencies, the methods for calibration, validation and data analysis are presented. Measurements of nebulised ammonium sulphate as well as of secondary organic aerosol generated from a smog chamber were performed. Agreement and discrepancies between the instruments and to the theory are discussed, and final recommendations for a standard instrument are given, as a benchmark for laboratory or field experiments to ensure a high quality of HTDMA data.JRC.H.2-Climate chang

Quantity increase and functional affinity/avidity decrease of anti-FcεRI and anti-IgE autoantibodies in chronic spontaneous urticaria.

Background. Patients with autoimmune forms of chronic spontaneous urticaria (aiCSU) exhibit autoantibodies against the high-affinity IgE receptor (FcεRI) and IgE. As the presence of these autoantibodies does not correlate with disease activity, the functional affinity/avidity may be relevant in aiCSU. This exploratory study aimed to characterize the quantity and avidity of autoantibodies against IgE and FcεRI over 6 months. Methods. The serum of 49 patients with CSU and 30 healthy control subjects was obtained at baseline and 6 months. Serum was analyzed by ELISA, to determine the quantity and avidity of anti-IgE and anti-FcεRI autoantibodies, and by basophil activation test (CU-BAT). Results. An increase in the quantity of anti-FcεRI and anti-IgE antibodies and a simultaneous decrease in avidity was found in all patients with CSU after 6 months: median anti-IgE increased from 6.7 ng/mL (IQR 5.1-12.5) to 23.8 ng/mL (IQR 12.3-121.5), p less than 0.001, median anti-FcεRI from 52.4 ng/mL (IQR 26.3-111.4) to 129.5 ng/mL (IQR 73.7-253.7), p less than 0.001. Median anti-IgE avidity decreased from 75.8% (IQR 55.3-90.8) to 56.4% (IQR 30.6-76.2), p=0.019 and median anti-FcεRI avidity from 75.1% (IQR 49.8-90.0) to 52.2 (IQR 38.2-60.1), p less than 0.001. In contrast, the frequency of activated basophils did not change significantly over time. Surprisingly, autoantibody avidity did not correlate with basophil activation. Conclusions. Both the quantity and avidity of anti-FcεRI and anti-IgE antibodies change over time, demonstrating that the CU-BAT is more suitable to diagnose aiCSU. In addition, the avidity of anti-FcεRI and anti-IgE antibodies do not correlate with CU-BAT and disease activity, suggesting that further factors independent of anti-FcεRI and anti-IgE autoantibodies contribute to aiCSU

Intercomparison study of six HTDMAs : results and recommendations

We report on an intercomparison of six different hygroscopicity tandem differential mobility analysers (HTDMAs). These HTDMAs are used worldwide in laboratory experiments and field campaigns to measure the water uptake of aerosol particles and have never been intercompared. After an investigation of the different design of the instruments with their advantages and inconveniencies, the methods for calibration, validation and data analysis are presented. Measurements of nebulised ammonium sulphate as well as of secondary organic aerosol generated from a smog chamber were performed. Agreement and discrepancies between the instruments and to the theory are discussed, and final recommendations for a standard instrument are given, as a benchmark for laboratory or field experiments to ensure a high quality of HTDMA data.Peer reviewe

A 17 month climatology of the cloud condensation nuclei number concentration at the high alpine site Jungfraujoch

Between May 2008 and September 2009 the cloud condensation nuclei (CCN) number concentration, N-CCN, was measured at the high alpine site Jungfraujoch, which is located in the free troposphere most of the time. Measurements at 10 different supersaturations (0.12%-1.18%) were made using a CCN counter (CCNC). The monthly median NCCN values show a distinct seasonal variability with similar to 5-12 times higher values in summer than in winter. The major part of this variation can be explained by the seasonal amplitude of total aerosol number concentration (similar to 4.5 times higher values in summer), but it is further amplified (factor of similar to 1.1-2.6) by a shift of the particle number size distribution toward slightly larger sizes in summer. In contrast to the extensive properties, the monthly median of the critical dry diameter, above which the aerosols activate as CCN, does not show a seasonal cycle (relative standard deviations of the monthly median critical dry diameters at the different supersaturations are 4-9%) or substantial variability (relative standard deviations of individual data points at the different supersaturations are less than 18-37%). The mean CCN-derived hygroscopicity of the aerosol corresponds to a value of the hygroscopicity parameter k of 0.20 (assuming a surface tension of pure water) with moderate supersaturation dependence. NCCN can be reliably predicted throughout the measurement period with knowledge of the above-mentioned averaged k value and highly time-resolved (similar to 5 min) particle number size distribution data. The predicted N-CCN was within 0.74 to 1.29 times the measured value during 80% of the time (94,499 data points in total at 10 different supersaturations)

Novel Principle of Aero/Hydro-Dynamic Lift Creation, Methods of Its Technical Implementation and Prospects of Its Application

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Создание максимально возможной подъемной силы является актуальной задачей для ряда технических устройств: летательных аппаратов, подводных аппаратов, ветрогенераторов, гидрогенераторов и т. д. К сожалению, все известные в настоящее время методы создания аэро/гидродинамической подъемной силы уже полностью используются. Тем не менее, авторы этой статьи обнаружили новый принцип создания подъемной силы, представленный в этой статье и названный авторами «энергодифференциальный принцип создания аэро/гидродинамической подъемной силы». Этот новый принцип может использоваться как в сочетании с традиционными методами создания подъемной силы, так и в отдельности. В статье рассматриваются различные способы реализации энергодифференциального принципа создания аэро/гидродинамической подъемной силы и возможности его применения в авиации, ветроэнергетике и др. Показано, что использование этого принципа позволяет, в частности, создать новый тип ветрогенераторов, которые будут более энергоэффективными, чем существующие. Creating the highest possible lifting force is an urgent task for a number of technical devices: aircraft, underwater apparatuses, wind generators, hydro-generators, etc. Unfortunately, all currently known methods of aero/hydro lift creation are already completely used. However, the authors of this paper discovered a novel principle of creating lift, presented in this paper and named by the authors “energy-difference principle of creation of the aero/hydro-dynamic lift”. This new principle can be used both in combination with traditional methods of creating a lifting force and separately. The paper discusses various methods of implementing energy-difference principle of creation of the aero/hydro-dynamic lift and the possibility of its application in aviation, wind power, etc. It is shown that the use of this principle allows, in particular, to create a new type of wind generators that are more energy efficient than the existing ones