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Sustainable economic development is also determined by the availability of primary energy supply. Geographical incoherence of energy production and consumption areas leads to new challenges in providing consumers with energy. The purpose of this work is to analyze and assess trends and problems related to the provision of energy resources, mainly of the natural gas for Republic of Moldova in the context of new challenges in the natural gas market and rhe changes in their transport infrastructure. The investigative methodology is based on the analysis of time series of production, consumption and import of energy resources at global and regional level in 1990-2017. It is proposed to using the linear approximation functions. The coefficients and the its signs of these functions ("plus" or "minus") and the value of and the determination coefficient are used for the quantitative analysis of the production, consumption and import trends of primary energy and natural gas. Europe and Asia ensure their energy balance by massive energy imports. The Southeast European region, including the Republic of Moldova, imports large sums of primary energy resources. The need to import natural gas in the Romania-Moldova-Ukraine sub-zone is currently estimated at about 12 million tons of oil equivalent. The new energy corridors for the transportation of natural gas will lead to new challenges regarding the natural gas supply of the Republic of Moldova. Information on possible scenarios of natural gas supply to the Republic of Moldova is presented and the estimated costs for natural gas transport for these scenarios are presented.

The purpose of this paper is to estimate the possibility of technical use of the 110 kV voltage lines (OPL) for the interconnection of the power systems of the Republic of Moldova and Romania, taking into account in the unified power system regime, which includes the power system of the CIS countries, of Moldova, Romania, Ukraine and other countries in the region.In the calculation scheme of the permanent synchronous regime of the integrated system, the interconnection zone of the Moldovan and Romanian systems was highlighted for the lines of 110 kV: Stanca-Costeşti, Ţuţora (Fai) -Ungheni and Hushi-Cioara.Transformer phase difference angle adjustment devices have been introduced in the 110 kV OPLto provide the bidirectional power shift regime. In the existing topology of electricity networks, power flows at the power system interface are directed from the Republic of Moldova to Romania.Changing the direction of the power flows is possible through the 110 kV OPLA when equipped with phase shift devices. The results of the calculations of the permanent regime have demonstrated the possibility of achieving the reciprocal power exchange regime between the interconnected power systems by adjusting the phase difference angle. It was shown the possibility of stable operation when using 110 kV overheadpowerlines as interconnection lines of the Moldovan and Romanian power systems.The issue of interconnection through the 110 kV lines is complex and requires an individual approach to how to achieve it.

Types of intersystem controlled tie-lines, that may allow the joint work of power systems of Moldova, Ukraine and Romania, are proposed in this paper. The use of intersystem controlled ac transmission lines based on compact one-circuit overhead transmission lines (OHTL) and two-circuit controlled self-compensated OHTL (CSCTL) with phase-shifting transformers on the other hand is also stated. Two types of phase-shifting transformers are considered: the first one – with bounded range of phase angle control between the voltage vectors’ system at the output with respect to the other at the input; the second one – with circular rotation of one voltage vectors’ system with respect to the other. The first type of devices is aimed to control the power flows within the system or through the intersystem tie-lines of synchronously operating systems. The second type of phase-shifting transformers is aimed to interconnect power systems that operate non-synchronously and to control the power flows between them through connecting OHTL. The first type of devices was introduced in calculation model in 330 kV Moldavskaya GRES – Chisinau OHTL and the second one – in the OHTL that are connecting the power systems of Moldova and Romania. The dependences of power flows through power system’s and intersystems’ OHTL are established on base of performed calculations, research and analysis.

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

Subtle anomalies in how the structure of metallic osmium evolves with pressure are detected using powder X-ray diffraction measurements at ultra-high static pressures; the anomaly at 440 gigapascals is attributed to an electronic transition caused by pressure-induced interactions between core electrons. Osmium at extreme pressures The platinum group element osmium is one of the most incompressible of all metals and little is known about its response to extreme compression because the required pressure regime is so difficult to reach. Leonid Dubrovinsky et al. now report powder X-ray diffraction observations of osmium at unprecedentedly high static pressures attained using the state-of-the-art micro-ball nanodiamond anvil cell technique. They detect subtle anomalies in how the structure of the metal evolves at pressures above 770 gigapascals (7.7 megabars). Advanced calculations attribute the anomalies to a type of electronic transition previously unknown for the platinum group and similar metals and caused by pressure-induced interactions between core electrons. The core-level crossing or CLC transition involves pressure-induced interactions between core electrons, leading to observable changes of the material properties. The ability to perform experiments at static pressures that affect the core electrons of even the most incompressible of elements opens up new avenues in the search for new states of matter under extreme conditions. Metallic osmium (Os) is one of the most exceptional elemental materials, having, at ambient pressure, the highest known density and one of the highest cohesive energies and melting temperatures.sup.1. It is also very incompressible.sup.2,3,4, but its high-pressure behaviour is not well understood because it has been studied.sup.2,3,4,5,6 so far only at pressures below 75 gigapascals. Here we report powder X-ray diffraction measurements on Os at multi-megabar pressures using both conventional and double-stage diamond anvil cells.sup.7, with accurate pressure determination ensured by first obtaining self-consistent equations of state of gold, platinum, and tungsten in static experiments up to 500 gigapascals. These measurements allow us to show that Os retains its hexagonal close-packed structure upon compression to over 770 gigapascals. But although its molar volume monotonically decreases with pressure, the unit cell parameter ratio of Os exhibits anomalies at approximately 150 gigapascals and 440 gigapascals. Dynamical mean-field theory calculations suggest that the former anomaly is a signature of the topological change of the Fermi surface for valence electrons. However, the anomaly at 440 gigapascals might be related to an electronic transition associated with pressure-induced interactions between core electrons. The ability to affect the core electrons under static high-pressure experimental conditions, even for incompressible metals such as Os, opens up opportunities to search for new states of matter under extreme compression., Author(s): L. Dubrovinsky [sup.1] , N. Dubrovinskaia [sup.2] , E. Bykova [sup.1] [sup.2] , M. Bykov [sup.2] , V. Prakapenka [sup.3] , C. Prescher [sup.3] , K. Glazyrin [sup.4] , [...]

Laser heating in a diamond anvil cell (DAC) is a common method for studying material behavior at high-pressure and high-temperature conditions. It has been previously proven that during continuous wave (CW) laser heating of a sample, carbon of the diamond anvils is mobilized, and its diffusion into the sample can lead to undesirable chemical reactions, which, if not detected, may cause misinterpretations of the results of the experiment. Minimizing the heating time with the use of a pulsed laser (PL) is thought to reduce the risk of possible carbon contamination of the sample; however, this has not been proven experimentally. Here, we report the results of our comparative study of the effect of pulsed and continuous wave (CW) laser heating on the mobilization of carbon and its chemical interaction with iron in a diamond anvil cell. Using X-ray absorption near edge structure spectroscopy, Synchrotron Mössbauer Source spectroscopy, and Synchrotron X-ray diffraction, we examined iron samples that were laser heated in DACs in various pressure transmitting media (neon, argon, and potassium chloride). According to our results, the use of the PL heating does not prevent the sample from carbon contamination. A reaction between carbon and iron happens within a few seconds even at moderate temperatures. We found that one analytical technique was generally insufficient to fully characterize the phase composition of the laser-heated samples. [ABSTRACT FROM AUTHOR]