Imbibition assisted oil recovery

Imbibition describes the rate of mass transfer between the rock and the fractures. Therefore, understanding the imbibition process and the key parameters that control the imbibition process is crucial. Capillary imbibition experiments usually take a long time, especially when we need to vary some parameters to investigate their effects. Therefore, this research presented the numerical studies with the matrix block surrounded by the wetting phase for better understanding the characteristic of spontaneous imbibition, and also evaluated dimensionless time for validating the scheme of upscaling laboratory imbibition experiments to field dimensions. Numerous parametric studies have been performed within the scope of this research. The results were analyzed in detail to investigate oil recovery during spontaneous imbibition with different types of boundary conditions. The results of these studies have been upscaled to the field dimensions. The validity of the new definition of characteristic length used in the modified scaling group has been evaluated. The new scaling group used to correlate simulation results has been compared to the early upscaling technique. The research revealed the individual effects of various parameters on imbibition oil recovery. Also, the study showed that the characteristic length and the new scaling technique significantly improved upscaling correlations

On regional security governance once again: how analysis of the Southern Caucasus can advance the concept

Already introduced to the academic and political debate some years ago, the concept of “security governance” still needs to be clarified. In particular, four main shortcomings need to be overcome to make the concept more useful for an assessment of current security dynamics: in the first place, attention has been devoted more to “governance” than to “security”, while failing to consider the role of the understandings and perceptions of the actors involved in the governance system. Second, the literature on the actors (governmental or not) involved is still fragmented. Third, the literature on security governance has too often been detached from reflections on regionalism, while it would be useful to further explore the relationship between cognitive definitions of regional and security dynamics. Fourth, the literature has predominantly focused on Europe and the transatlantic area, overlooking processes of “region-building” in security terms in other “unexpected” geographical spaces. After proposing avenues to overcome the current gaps in the literature, the Southern Caucasus is chosen as a case study to show the different instances of security governance emerging, thanks to definitions of the region in security terms that have involved regional and external actors, of a state and non-state nature

A health risk assessment for fluoride in Central Europe

Like many elements, fluorine (which generally occurs in nature as fluoride) is beneficial to human health in trace amounts, but can be toxic in excess. The links between low intakes of fluoride and dental protection are well known; however, fluoride is a powerful calcium-seeking element and can interfere with the calcified structure of bones and teeth in the human body at higher concentrations causing dental or skeletal fluorosis. One of the main exposure routes is via drinking water and the World Health Organisation currently sets water quality guidelines for the element. In Central Europe, groundwater resources that exceed the guideline value of 1.5 mg l-1 are widespread and effects on health of high fluoride in water have been reported. The aim of the current project was to develop a geographic information system (GIS) to aid the identification of areas where high-fluoride waters and fluorosis may be a problem; hence, where water treatment technologies should be targeted. The development of the GIS was based upon the collation and digitisation of existing information relevant to fluoride risk in Ukraine, Moldova, Hungary and Slovakia assembled for the first time in a readily accessible form. In addition, geochemistry and health studies to examine in more detail the relationships between high-fluoride drinking waters and health effects in the population were carried out in Moldova and Ukraine demonstrating dental fluorosis prevalence rates of 60–90% in adolescents consuming water containing 2–7 mg l-1 fluoride

Competing magnetic and structural states in multiferroic YMn2{_2}O5{_5} at high pressure

The magnetic, structural, and vibrational properties of YMn${_2}$O${_5}$ multiferroic have been studied bymeans of neutron, x-ray powder diffraction, and Raman spectroscopy at pressures up to 6 and 30 GPa,respectively. Application of high pressure,P >1 GPa, leads to a gradual suppression of the commensurate andincommensurate antiferromagnetic (AFM) phaseswith a propagation vector q = (1/2,0,q${_z}$∼1/4) and appearanceof the commensurate AFM phase with q = (1/2,0,1/2). This observation is sharply contrasting to general trendtowards stabilization of commensurate AFM phase with q = (1/2,0,1/4) found in other RMn${_2}$O${_5}$ compoundsupon lattice compression. At P ∼ 16 GPa a structural phase transformation accompanied by anomalies in latticecompression and pressure behavior of vibrational modeswas observed. The comparative analysis of high-pressureand R-cation radius variation effects clarified a role of particular magnetic interactions in the formation of themagnetic states of RMn${_2}$O${_5}$ compounds