This paper is focused on improving the quality of nowcasting solar irradiance by enhancing the clear sky component of the model. A simple linear correction for the average atmospheric transmittance is proposed. The correction is based on the most recent measurements recorded prior the forecasting moment. The proposed procedure was tested against data measured on the Solar Platform of the West University of Timisoara. Overall results demonstrates a notable improvement in the clear sky model accuracy.
Intercomparison exercises of radon instruments play an important part when it comes to domestic survey as well as international or national mapping in dwellings, soil or water. Therefore, it is of prime interest to improve and standardize technical methods of measurement and also to verify quality assurance through comparison between different instruments and techniques. In the present paper is described the latest intercomparison exercise performed between the Laboratory of Environmental Radioactivity (hereafter called LER) of our department and other 15 different teams around Europe. The test has been held at two radon reference sites located 60 km SW of Prague, Czech Republic.
Carmen Ionescu, Emilian Panaitescu and Mihai Stoicescu
In most of the applications involving neural networks, the main problem consists in finding an optimal procedure to reduce the real neuron to simpler models which still express the biological complexity but allow highlighting the main characteristics of the system. We effectively investigate a simple reduction procedure which leads from complex models of Hodgkin-Huxley type to very convenient binary models of Hopfield type. The reduction will allow to describe the neuron interconnections in a quite large network and to obtain information concerning its symmetry and stability. Both cases, on homogeneous voltage across the membrane and inhomogeneous voltage along the axon will be tackled out. Few numerical simulations of the neural flow based on the cable-equation will be also presented.
In this paper it is present a non contact method for 3D measurements on parabolic surface antenna. In order to obtain modal parameters and modal shapes of a parabolic surface antenna a Microflown USP (Ultimate Sound Probe) is used. Microflown sensors are close to antenna and can be used for the non contact measurement of the normal component of the structural velocity.
The information-theoretical entropy, also called the “classical” entropy, was introduced by Wehrl in terms of the Glauber coherent states (CSs) | z > , i.e. the CSs corresponding to the one-dimensional harmonic oscillator (HO-1D). In the present paper, we have focused our attention on the examination of the information-theoretical entropy, i.e. the Wehrl entropy, for both the pure and the mixed (thermal) states of some quantum oscillators.
Ivan Banik, Jozefa Lukovičová, Gabriela Pavlendová and Rudolf Podoba
The paper deals with the problem of decreasing level of knowledge of university students due to the changes of the school system in Slovakia. As the commonly repeated words connected with education in 21st.century are key competencies, we tried to look at the problems and challenges in teaching physics from this point of view. The role of classical experiments in our computerized world is also discussed.
It is shown that the bending of FCN and FNC molecules adsorbed on Si (100) - (2 × 1) surface, is due to the Renner-Teller effect induced by the orbital charge transfers by adsorption. From ab initio calculations of free FCN and FNC and the molecules adsorbed on the model Si9H12 cluster, the orbital charge transfers to and from the molecules were calculated, the vibronic coupling constants were estimated, and the curvature K of the adiabatic potentials for the bending coordinate of adsorbed molecules was evaluated. Calculations show that for both side-on adsorbed species, as well as for end-on adsorbed FNC molecule K<0 that leads to their bending. For the end-on adsorbed FCN K>0, and this molecule remains linear
Strontium aluminate (SrAl2O4) and the indium aluminate (SrIn2O4) spinels have been proven to be efficient host materials, which offer the possibility of generating broadband emission after doping with rare earth trivalent ions. The present work is devoted to the calculation of the crystal field parameters and the energy levels of the trivalent europium doped in SrAl2O4 and SrIn2O4 spinels, using the superposition model of the crystal field. Using the intrinsic parameters for Eu3+-O2− bonds, and the geometry structure of the each crystal, we modeled the CFPs and simulated the low-lying energy levels schemes. The obtained results are compared with the experimental data and discussed.
Zinc aluminate (ZnAl2O4) doped with rare earth metal ions has been investigated most frequently because of the unique luminescent properties resulting from its stability and high emission quantum yields. The present work is devoted to calculate the Judd-Ofelt parameters (Ω2, Ω4 and Ω6) of the trivalent europium doped in ZnAl2O4 spinel, the quality factor (Q) and the branching ratio (β).