Selection and inspection of power plant elements with application of probability methods

Probabilistic criteria of overload and destruction risks at substantiation of the chosen power components of electric installations under operating conditions and emergency influences are developed. The example of inspection of rigid modular trunks of the Surgut State District Power Station-1 is shown

From Solar to Stellar Brightness Variations: The Effect of Metallicity

Context. Comparison studies of Sun-like stars with the Sun suggest an anomalously low photometric variability of the Sun compared to Sun-like stars with similar magnetic activity. Comprehensive understanding of stellar variability is needed, to find a physical reasoning for this observation. Aims. We investigate the effect of metallicity and effective temperature on the photometric brightness change of Sun-like stars seen at different inclinations. The considered range of fundamental stellar parameters is sufficiently small so the stars, investigated here, still count as Sun-like or even as solar twins. Methods. To model the brightness change of stars with solar magnetic activity, we extend a well established model of solar brightness variations, SATIRE (which stands for Spectral And Total Irradiance Reconstruction), which is based on solar spectra, to stars with different fundamental parameters. For that we calculate stellar spectra for different metallicities and effective temperature using the radiative transfer code ATLAS9. Results. We show that even a small change (e.g. within the observational error range) of metallicity or effective temperature significantly affects the photometric brightness change compared to the Sun. We find that for Sun-like stars, the amplitude of the brightness variations obtained for Str\"omgren (b + y)/2 reaches a local minimum for fundamental stellar parameters close to the solar metallicity and effective temperature. Moreover, our results show that the effect of inclination decreases for metallicity values greater than the solar metallicity. Overall, we find that an exact determination of fundamental stellar parameters is crucially important for understanding stellar brightness changes.Comment: 12 pages, 12 figures, accepted in A&

A new approach to long-term reconstruction of the solar irradiance leads to large historical solar forcing

The variable Sun is the most likely candidate for natural forcing of past climate change on time scales of 50 to 1000 years. Evidence for this understanding is that the terrestrial climate correlates positively with solar activity. During the past 10,000 years, the Sun has experienced substantial variations in activity and there have been numerous attempts to reconstruct solar irradiance. While there is general agreement on how solar forcing varied during the last several hundred years --- all reconstructions are proportional to the solar activity --- there is scientific controversy on the magnitude of solar forcing. We present a reconstruction of the Total and Spectral Solar Irradiance covering 130 nm--10 $\mu$m from 1610 to the present with annual resolution and for the Holocene with 22-year resolution. We assume that the minimum state of the quiet Sun in time corresponds to the observed quietest area on the present Sun. Then we use available long-term proxies of the solar activity, which are $^{10}$Be isotope concentrations in ice cores and 22-year smoothed neutron monitor data, to interpolate between the present quiet Sun and the minimum state of the quiet Sun. This determines the long-term trend in the solar variability which is then superposed with the 11-year activity cycle calculated from the sunspot number. The time-dependent solar spectral irradiance from about 7000 BC to the present is then derived using a state-of-the-art radiation code. We derive a total and spectral solar irradiance that was substantially lower during the Maunder minimum than observed today. The difference is remarkably larger than other estimations published in the recent literature. The magnitude of the solar UV variability, which indirectly affects climate is also found to exceed previous estimates. We discuss in details the assumptions which leaded us to this conclusion.Comment: 9 pages, 5 figures, accepted for publication in Astronomy&Astrophysic

The role of the Fraunhofer lines in solar brightness variability

The solar brightness varies on timescales from minutes to decades. A clear identification of the physical processes behind such variations is needed for developing and improving physics-based models of solar brightness variability and reconstructing solar brightness in the past. This is, in turn, important for better understanding the solar-terrestrial and solar-stellar connections. We estimate the relative contributions of the continuum, molecular, and atomic lines to the solar brightness variations on different timescales. Our approach is based on the assumption that variability of the solar brightness on timescales greater than a day is driven by the evolution of the solar surface magnetic field. We calculated the solar brightness variations employing the solar disc area coverage of magnetic features deduced from the MDI/SOHO observations. The brightness contrasts of magnetic features relative to the quiet Sun were calculated with a non-LTE radiative transfer code as functions of disc position and wavelength. By consecutive elimination of molecular and atomic lines from the radiative transfer calculations, we assessed the role of these lines in producing solar brightness variability. We show that the variations in Fraunhofer lines define the amplitude of the solar brightness variability on timescales greater than a day and even the phase of the total solar irradiance variability over the 11-year cycle. We also demonstrate that molecular lines make substantial contribution to solar brightness variability on the 11-year activity cycle and centennial timescales. In particular, our model indicates that roughly a quarter of the total solar irradiance variability over the 11-year cycle originates in molecular lines. The maximum of the absolute spectral brightness variability on timescales greater than a day is associated with the CN violet system between 380 and 390 nm.Comment: 9 pages, 4 figures, accepted for publication in Astronomy&Astrophysic

Application of the probabilistic technologies to power plant design

In the report the developed approach for choice and substantiation of power equipment, current-carrying parts and switching devices using existing and proposed probabilistic method of borders selection of input and output data (SBID) is presented. SBID method allows to receive complete probabilistic characteristics or probability distribution laws (PDL) of output data as functional dependence from the arguments (input data) by probabilistic characteristics of arguments. Any task, including electrical values in operating modes and transient conditions in power system can be exposed as dependence on input or output data. Due to SBID method, the PDL of input data processing results of these dependencies may be received. PDL allows to calculate risks of overload of the power components in the operating modes and destruction, also power equipment parameters, current-carrying parts and switching devices are going to be selected on the basis of the minimum specified risks

The in vivo quantitative assessment of the effectiveness of low-dose photodynamic therapy on wound healing using optical coherence tomography

The effect of low-dose photodynamic therapy on in vivo wound healing was investigated using optical coherence tomography. This work aims to develop an approach to quantitative assessment of the wound’s state during wound healing including the effect of low-dose photodynamic therapy using topical application of two different photosensitizers, 5-aminolevulinic acid and methylene blue, and two laser doses of 1 J/cm2 and 4 J/cm2. It was concluded that the laser dose of 4 J/cm2 was better compared to 1 J/cm2 and allowed the wound healing process to accelerate

Properties of sunspots in cycle 23: I. Dependence of brightness on sunspot size and cycle phase

In this paper we investigate the dependence of umbral core brightness, as well as the mean umbral and penumbral brightness on the phase of the solar cycle and on the size of the sunspot. Albregtsen & Maltby (1978) reported an increase in umbral core brightness from the early to the late phase of solar cycle from the analysis of 13 sunspots which cover solar cycles 20 and 21. Here we revisit this topic by analysing continuum images of more than 160 sunspots observed by the MDI instrument on board the SOHO spacecraft for the period between 1998 March to 2004 March, i.e. a sizable part of solar cycle 23. The advantage of this data set is its homogeneity, with no seeing fluctuations. A careful stray light correction, which is validated using the Mercury transit of 7th May, 2003, is carried out before the umbral and penumbral intensities are determined. The influence of the Zeeman splitting of the nearby NiI spectral line on the measured 'continuum' intensity is also taken into account. We did not observe any significant variation in umbral core, mean umbral and mean penumbral intensities with solar cycle, which is in contrast to earlier findings for the umbral core intensity. We do find a strong and clear dependence of the umbral brightness on sunspot size, however. The penumbral brightness also displays a weak dependence. The brightness-radius relationship has numerous implications, some of which, such as those for the energy transport in umbrae, are pointed out.Comment: 16 pages, 21 postscript figures, accepted for publication in A&

In vivo quantification of the effectiveness of topical low-dose photodynamic therapy in wound healing using two-photon microscopy

The effect of low-dose photodynamic therapy on in vivo wound healing with topical application of 5-aminolevulinic acid and methylene blue was investigated using an animal model for two laser radiation doses (1 and 4 J/cm2). A second-harmonic-generation-to-auto-fluorescence aging index of the dermis (SAAID) was analyzed by two-photon microscopy. SAAID measured at 60–80 μm depths was shown to be a suitable quantitative parameter to monitor wound healing. A comparison of SAAID in healthy and wound tissues during phototherapy showed that both light doses were effective for wound healing; however, healing was better at a dose of 4 J/cm2

ВІДБІР ІНФОРМАТИВНИХ ПОКАЗНИКІВ ВАРІАБЕЛЬНОСТІ РИТМУ СЕРЦЯ – МАРКЕРІВ РЕАКЦІЇ НА ЕМОЦІЙНІ СТИМУЛИ

On the basis of multivariate statistical analysis developed method for the separation of informative indicators of heart rate variability (HRV), which have diagnostic value for the objective assessment of operator's emotional reaction from watching emotive videos. The technique consists of two stages: 1) multivariate analysis of variance; 2) stepwise discriminate analysis with different strategies of feature selection. The total average classification accuracy 4 states of operators by 10 informative indices (two of which are indicators of the results of self -report and other indicators HRV) reached 95.7 %.На основе методов многомерного статистического анализа разработана двухэтапная методика выделения информативных показателей вариабельности ритма сердца (ВРС), имеющих диагностическую ценность для объективной оценки реакции операторов на эмоционально окрашенные видеоклипы. Методика состоит из двух этапов: 1) многомерного дисперсионного анализа; 2) пошагового дискриминантного анализа с различными стратегиями отбора признаков. Общая средняя точность классификации четырех состояний операторов по 10 информативным показателям (два из которых - по результатам самоотчета, а другие показатели - вариабельности ритма) достигала 95,7 %.На основі методів багатовимірного статистичного аналізу розроблено методику виділення інформативних показників варіабельності ритму серця (ВРС), що мають діагностичну цінність для об'єктивної оцінки реакції операторів на емоційно забарвлені відеокліпи. Методика складається з двох етапів: 1) багатомірного дисперсійного аналізу; 2) покрокового дискримінатного аналізу з різними стратегіями відбору ознак. Загальна середня точність класифікації чотирьох станів операторів за 10 інформативними показниками (два з яких - за результатами самозвіту, а інші показники варіабельності ритму) досягала 95,7 %