Measurability of kinetic temperature from metal absorption-line spectra formed in chaotic media

We present a new method for recovering the kinetic temperature of the intervening diffuse gas to an accuracy of 10%. The method is based on the comparison of unsaturated absorption-line profiles of two species with different atomic weights. The species are assumed to have the same temperature and bulk motion within the absorbing region. The computational technique involves the Fourier transform of the absorption profiles and the consequent Entropy-Regularized chi^2-Minimization [ERM] to estimate the model parameters. The procedure is tested using synthetic spectra of CII, SiII and FeII ions. The comparison with the standard Voigt fitting analysis is performed and it is shown that the Voigt deconvolution of the complex absorption-line profiles may result in estimated temperatures which are not physical. We also successfully analyze Keck telescope spectra of CII1334 and SiII1260 lines observed at the redshift z = 3.572 toward the quasar Q1937--1009 by Tytler {\it et al.}.Comment: 25 pages, 6 Postscript figures, aaspp4.sty file, submit. Ap

Bounds on the fine structure constant variability from FeII absorption lines in QSO spectra

The Single Ion Differential alpha Measurement (SIDAM) method for measuring fine stucture variations (daa)and its figures of merit are illustrated together with the results produced by means of FeII absorption lines of QSO intervening systems. The method provides daa ~= -0.12(+/- 1.79) ppm (parts-per-million) at zabs = 1.15 towards HE 0515--4414 and daa = 5.66(+/-2.67) ppm at zabs= 1.84 towards Q 1101--264, which are so far the most accurate measurements for single systems. SIDAM analysis for 3 systems from the Chand et al. (2004) sample provides inconsistent results which we interpret as due to calibration errors of the Chand et al. data at the level of about 10 ppm. In one system evidence for photo-ionization Doppler shift between MgII and FeII lines is found. This evidence has important bearings on the Many Multiplet method where the signal for daa variability is carried mainly by systems involving MgII absorbers. Some correlations are also found in the Murphy et al. sample which suggest larger errors than previously reported. Thus, we consider unlikely that both the Chand et al. and Murphy et al. datasets could provide an estimate of daa with an accuracy at the level of 1 ppm. A new spectrograph like the ESPRESSO project will be crucial to make progress in the astronomical determination of daa.Comment: Talk given at ACFC 2007 "Atomic Clocks and Fundamental Constants" conference, Bad Honnef, June 2007, Savely Karshenboim and Ekkehard Peik editor

High-Precision Measurements of Delta alpha/alpha from QSO Absorption Spectra

Precise radial velocity measurements (delta v/c ~ 10^{-7}) of FeII lines in damped Ly-alpha systems from very high quality VLT/UVES spectra of quasars HE0515-4414 and Q1101-264 are used to probe cosmological time dependence of the fine structure constant, alpha. It is found that between two redshifts z1 = 1.15 and z2 = 1.84 the value of Delta alpha/alpha changes at the level of a few ppm: (alpha_z2 - alpha_z1)/alpha_0 = 5.43 +/- 2.52 ppm. Variations of alpha can be considered as one of the most reliable method to constrain the dark energy equation of state and improvements on the accuracy of the wavelength calibration of QSO spectra are of great importance.Comment: 4 pages, 2 figures, Invited contribution to the proceedings of "Precision Spectroscopy in Astrophysics", Aveiro, Portugal, 11-15 Sep. 2006, eds. L. Pasquini, M. Romaniello and N. C. Santos (Springer-Verlag series "ESO Astrophysics Symposia"

Research for Modification of Concrete with Ash-containing Waste of Dnistrovska PSPS (Ukraine)

The object of reseaerch is concrete samples modified with ash-containing fillers and plasticizers. As practice shows, the use of secondary resources is an important issue in the field of construction and entails significant savings. The issue is also considered from the point of view of environmental protection. The study is aimed at determining the effect of modification of concrete with ash-containing waste on the strength characteristics using the example of the hydroelectric power station of the Dnistrovska PSPS (Sokyriany district, Chernivtsi region, Ukraine). The main hypothesis of the study is the assumption that varying components such as fly ash, water glass, and superplasticizers will make it possible to obtain concrete with specified strength characteristics. To achieve the aim, the authors decided to use in the study the superplasticizer SikaPlast-520N and BETO-plast, Portland cement M400 and sands of the quarries of the Parkan and Suklei regions (Moldova). According to the plan of the experiment, studies of the influence of hardening conditions on the structure and properties of modified concrete samples were carried out. Destructive testing of samples was carried out in the laboratory directly on a hydraulic press.The results of experiments without the addition of liquid glass and the introduction of a minimum amount of fly ash and experiments with the introduction of a minimum amount of fly ash and the addition of 3 % water glass are presented. To determine the dynamics of strength gain, tests were carried out on 7, 14 and 28 days. The presented results of the study of the samples on day 7 show a gain of more than 50 % strength. This indicates the possibility of reducing the curing period of structural concrete in the formwork system. A more complete and objective idea of the quality of concrete is possible while taking into account the average strength of concrete and its homogeneity.Today, there is no unified theory that can relate the different properties of cement and filler to the final properties of a composite material. The issue of modifying concrete compositions when using fine aggregate from other quarries requires additional research. At the same time, the results of the experiment show that the use of microfillers based on wastes from the Dnistrovska PSPS provide ample opportunities not only for saving binders, but also for improving the physical, mechanical and operational characteristics of concrete

High-Precision Measurements of Deltaalphaalpha, from QSO Absorption Spectra

International audiencePrecise radial velocity measurements (deltaupsilo/c ˜ 10-7) of Fell lines in damped Lyalpha systems from very high quality VLT/UVES spectra of quasars HE 0515-4414 and Q 1101-264 are used to probe cosmological time dependence of the fine structure constant, alpha. It is found that between two redshifts z 1 = 1.15 and z 2 = 1.84 the value of Deltaalpha/alpha changes at the level of a few ppm: (alphaz2 --- alphaz1)/alpha0 = 5.43 ± 2.52 ppm. Variations of alpha can be considered as one of the most reliable method to constrain the dark energy equation of state and improvements on the accuracy of the wavelength calibration of QSO spectra are of great importance