In the paper, the Reynolds transport theorem (RTT) for three phase systems is developed, in terms associated with a moving control volume. The basic tools applied to the derivation are the generalized transport theorem by Truesdell and Toupin, and generalized surface transport theorem by Aris as well as Slattery. The final results referenced to a generic extensive quantity demonstrate the theorem in the integral instantaneous form. As a further illustration of applicability of the theorem relation developed some specific forms are deduced from such as for multiphase systems in terms of fixed control volume, surface systems and homogeneous spatial systems.

Structures and characteristics ofwideband small-size phase shiftersmade with the use of single parallel stubs are presented in this paper. The stubs can be short-circuited or open-circuited on termination. Such devices arewell known, but are primarily used as components of filters ormatching circuits. The novelty, then, comes from the establishment of simple, but helpful formulae, which enable to describe the insertion phase shift and differential phase shift of a line with short and open stubs connected in parallel. These equations can be very useful for designing complex microwave multi-ports. The results of simulations and measurements of the devices, which were designed and made, are shown herein. It was also proved that the presented devices have several usable operating frequency sub-bands, and that the differential phase shift values in the higher sub-bands are greater than those in the lower operating frequency ranges. Thanks to this, the described phase shifters can be used in more than one frequency sub-band. It was stated that in the conditions under analysis, larger phase shifts can be achieved using open-circuited stubs rather than short-circuited stubs. However, the phase shifters with shorted parallel stubs can operate in a wider frequency band.

The exact measurement of multiphase flow is an important and essential task in the oil and petrochemical related industries. Several methods have already been proposed in this field. In the existing methods, flow rate measurement depends on the fluid flow pattern. Flow pattern recognition requiring calibration has created instability in such systems. In this paper, a imple and reliable method is proposed which is based on ultrasonic tomography. It is free from calibration and instability problems that existing methods have. The obtained data from a 32-digit array of ultrasonic sensors have been used and the two-phase flow rate including liquid and gas phases have been calculated through a simple algebraic algorithm. Simulation results show that while applying this method the measurement technique is independent from the fluid flow pattern and the system error is decreased. For the proposed algorithm, the average amount of the spatial imaging error (SIE) for a bubble at different positions inside the pipe is about 5%.

To obtain anti-corrosive thermo-diffusion zinc coatings, the authors use highly effective zinc saturating mixtures. This technology makes it possible to obtain coatings with a high zinc content in the δ-phase as well as a zinc-rich phase of FeZn13 (ζ-phase) on the coating surface. As a result of long-term studies into the corrosion properties of thermo-diffusion zinc (TDZ) coatings conducted by the authors, a number of features of their corrosive behavior have been established. The corrosion rate of those coatings in desalted and chloride-containing media is lower than those of galvanic or hot-dip zinc coatings. The corrosion behavior depends on the content of zinc on the surface and the texture features of the coating. The results showed that on the surface of thermo-diffusion coatings in the corrosion on media containing chloride ions, zinc hydroxychloride (simonkolleite – Zn5Cl2[OH]8[H2O]) has been formed. Compared to coatings obtained by other methods, the rate of simonkolleite formation was higher on TDZ coatings, which might have a positive effect on their resistance in aggressive atmospheres.

The single-phase voltage loss is a common fault. Once the voltage-loss failure occurs, the amount of electrical energy will not be measured, but it is to be calculated so as to protect the interest of the power supplier. Two automatic calculation methods, the power substitution and the voltage substitution, are introduced in this paper. Considering the lack of quantitative analysis of the calculation error of the voltage substitution method, the grid traversal method and MATLAB tool are applied to solve the problem. The theoretical analysis indicates that the calculation error is closely related to the voltage unbalance factor and the power factor, and the maximum calculation error is about 6% when the power system operates normally. To verify the theoretical analysis, two three-phase electrical energy metering devices have been developed, and verification tests have been carried out in both the lab and field conditions. The lab testing results are consistent with the theoretical ones, and the field testing results show that the calculation errors are generally below 0.2%, that is correct in most cases.

In this paper we review the significant political events and economic forces shaping contemporary mi-gration within and into Europe. Various data sources are deployed to chronicle five phases of migration affecting the continent over the period 1945–2015: immediate postwar migrations of resettlement, the mass migration of ‘guestworkers’, the phase of economic restructuring and family reunion, asylum-seek-ing and irregular migration, and the more diverse dynamics unfolding in an enlarged European Union post-2004, not forgetting the spatially variable impact of the 2008 economic crisis. In recent years, in a scenario of rising migration globally, there has been an increase in intra-European migration com-pared to immigration from outside the continent. However, this may prove to be temporary given the convergence of economic indicators between ‘East’ and ‘West’ within the EU and the European Eco-nomic Area, and that ongoing population pressures from the global South, especially Africa, may inten-sify. Managing these pressures will be a major challenge from the perspective of a demographically shrinking Europe.