Electro-optic time profile monitors for femtosecond electron bunches at the soft x-ray free-electron laser FLASH

Precise measurements of the temporal profile of ultrashort electron bunches are of high interest for the optimization and operation of ultraviolet and x-ray free-electron lasers. The electro-optic (EO) technique has been applied for a single-shot direct visualization of the time profile of individual electron bunches at FLASH. This paper presents a thorough description of the experimental setup and the results. An absolute calibration of the EO technique has been performed utilizing simultaneous measurements with a transverse-deflecting radio-frequency structure that transforms the longitudinal bunch charge distribution into a transverse streak. EO signals as short as 60 fs (rms) have been observed using a gallium-phosphide (GaP) crystal, which is a new record in the EO detection of single electron bunches and close to the physical limit imposed by the EO material properties. The data are in quantitative agreement with a numerical simulation of the EO detection process

First results from the CERN Axion Solar Telescope (CAST)

Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.Comment: 4 pages, accepted by PRL. Final version after the referees comment

The search for solar axions in the CAST experiment

The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: g$_{a\gamma}<0.9\times10^{-10}$ GeV$^{-1}$ at 95% C.L. for axion masses m$_{a} <$ 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV.The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: g$_{a\gamma}<0.9\times10^{-10}$ GeV$^{-1}$ at 95% C.L. for axion masses m$_{a} <$ 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV

Standardizacija kontrolnih laboratorijskih metoda u mljekarstvu - određivanje količine suhe tvari u mlijeku

Suha tvar, odnosno suha tvar bez masti mlijeka, potonju dobivamo računskim putem iz analitičkih podataka, značajne su za kvalitetu mlijeka, za randman mliječnih proizvoda, a u mnogim zemljama predstavljaju i osnovu za cijenu mlijeka. Našim Pravilnikom (1970) propisana je donja granica 8,5"/o suhe tvari bez masti za normalno mlijeko, a izračunava se pomoću Fleischmannove formule. Analitičku problematiku u vezi navedenih sastojaka spominju i Đorđevič i Carić (1973). Doprinos traženju odgovarajuće analitičke metode je i predloženi rad

Multi-horizon air pollution forecasting with deep neural networks

Air pollution is a global problem, especially in urban areas where the population density is very high due to the diverse pollutant sources such as vehicles, industrial plants, buildings, and waste. North Macedonia, as a developing country, has a serious problem with air pollution. The problem is highly present in its capital city, Skopje, where air pollution places it consistently within the top 10 cities in the world during the winter months. In this work, we propose using Recurrent Neural Network (RNN) models with long short-term memory units to predict the level of PM10 particles at 6, 12, and 24 h in the future. We employ historical air quality measurement data from sensors placed at multiple locations in Skopje and meteorological conditions such as temperature and humidity. We compare different deep learning models’ performance to an Auto-regressive Integrated Moving Average (ARIMA) model. The obtained results show that the proposed models consistently outperform the baseline model and can be successfully employed for air pollution prediction. Ultimately, we demonstrate that these models can help decision-makers and local authorities better manage the air pollution consequences by taking proactive measures

Određivanje količine masti u slatkom vrhnju

Kontrola količine masti u slatkom vrhnju značajna je s tehnološkog stajališta za mljekarska poduzeća, a s kontrolnog, u odnosu mljekara-potrošač-inspekcija. U nastojanjima za primjenom jedinstvenih rutinskih analitičkih metoda u našoj praksi, poduzeli smo istraživanje butirometrijskih metoda određivanja mliječne masti u slatkom vrhnju. Iznijeti podaci mogu poslužiti kao osnova za razmatranje

МЕТОДИ ЗА ОПРЕДЕЛУВАЊЕ НА БЕНЗОАТИ И СОРБАТИ ВО ХРАНА

The results obtained from determination of benzoates and sorbates in different food matrix using High performance liquid chromatography and UV spectroscopy are presented in this paper. The obtained results from determination, using HPLC method 1, is accurate and precise enough for determination of benzoates and sorbates in cheese, jam, jelly, marmalade and fat. The total time for analysis of test samples (extraction and HPLC analysis) is less than 20 min. For HPLC method 2, sodium salicylate is used as an internal standard to improve the precision and accuracy of the method. The tests results showed that some compounds added in cookies as vanilla and flavoring substances in yoghurt and pickles, interferes with sodium benzoate and potassium sorbate signals. The obtained concentrations of benzoates and sorbates using HPLC method 2 were lower than the obtained concentration using UV method