Environmental Impact Assessment of High Pressure Water Scrubbing Biogas Upgrading Technology

The aim of this work was to assess the burdens of a process in terms of environmental and health impacts, resource depletion issues, and energy demand based on the ability of the Life Cycle Assessment methodology to link the environmental impacts with the mass and energy flows. The analysis was done in terms of process and environmental performances of high pressure water scrubbing (HPWS) system applied for biogas upgrading. The application of process simulation based on the Aspen Plus® software has been considered as supportive for the calculation of mass and energy balances. Data processed using GaBi 4: Software showed that global warming, acidification, and human toxicity potentials were the main impact categories associated with the HPWS process. These indicators are largely related to the exhaust gas from the desorption column and the indirect emissions generated during energy consumption. The life cycle inventory study resulted in the development of a database with a vast inventory of data regarding HPWS technology. A basis for assessing potential improvements in the environmental performance of the system is provided. Future studies in this area will address the economical evaluation of the HPWS technology, so as to maximize economic efficiency and minimize environmental impacts.     

Geoelectrical investigations by means of resistivity methods in karst areas in Romania

The applicability of resistivity methods to ground water investigations is well recognized. As water-saturated rock formations have a lower electrical resistivity than dry ones, an electrical resistivity survey should result in low resistivity anomalies. Normally, such anomalies are interpreted to indicate areas of potentially significant ground water flows. In karst areas, however, interpretation may not be as straightforward: for example, large electrically conductive domains can represent water bearing zones, whose fluid-permeability may be poor; alternatively, fast flow conduits, which may be unsaturated, occur as slender objects, and not as clear anomalous features. In order to deal with such extreme heterogeneities, resistivity investigations require some specific adjustments. One example is the so-called “mise à la masse” method. In Romania, it was used to trace the cold karst water inflows that detrimentally affected the commercial exploitation of a thermal spring, Hercules at Baile Herculane. Conventional geoelectrical approaches––such as using resistivity highs to detect air-filled cave passages, are proved to be less efficient in the considered karst investigations.     

Note on the evolution of a Miocene composite volcano in an extensional setting, Zârand Basin (Apuseni Mts., Romania)

Bontâu is a major eroded composite volcano filling the Miocene Zârand extensional basin, near the junction between the Codru-Moma and Highi?-Drocea Mountains, at the tectonic boundary between the South and North Apuseni Mountains. It is a quasi-symmetric structure (16–18 km in diameter) centered on an eroded vent area (9×4 km), buttressed to the south against Mesozoic ophiolites and sedimentary deposits of the South Apuseni Mountains. The volcano was built up in two sub-aerial phases (14–12.5 Ma and 11–10 Ma) from successive eruptions of andesite lava and pyroclastic rocks with a time-increasing volatile budget. The initial phase was dominated by emplacement of pyroxene andesite and resulted in scattered individual volcanic lava domes associated marginally with lava flows and/or pyroclastic block-and-ash flows. The second phase is characterized by amphibole-pyroxene andesite as a succession of pyroclastic eruptions (varying from strombolian to subplinian type) and extrusion of volcanic domes that resulted in the formation of a central vent area. Numerous debris flow deposits accumulated at the periphery of primary pyroclastic deposits. Several intrusive andesitic-dioritic bodies and associated hydrothermal and mineralization processes are known in the volcano vent complex area. Distal epiclastic deposits initially as gravity mass flows and then as alluvial volcaniclastic and terrestrial detritic and coal filled the basin around the volcano in its western and eastern part. Chemical analyses show that lavas are calc-alkaline andesites with SiO₂ ranging from 56–61%. The petrographical differences between the two stages are an increase in amphibole content at the expense of two pyroxenes (augite and hypersthene) in the second stage of eruption; CaO and MgO contents decrease with increasing SiO₂. In spite of a ～4 Ma evolution, the compositions of calc-alkaline lavas suggest similar fractionation processes. The extensional setting favored two pulses of short-lived magma chamber processes.     

On the orbital eccentricity on an eclipsing binary system

A new method is presented to precisely deduce the orbital eccentricity of an eclipsing binary from observed epochs of its light minima. Application to the system V526 Sagittarii givese=0.2220±0.0016.     

Equipotential surfaces in close binary systems: Remarks on the time-dependent potential function

By use of the mass-point model, the equations of the equipotential surfaces are reviewed. A difference between the time-dependent potential function and zero relative velocity surfaces is put in evidence. A drawback in the time-dependent transformation between (, , ) and (x, y, z) coordinate systems is underlined.     

Late Miocene–Quaternary volcanism, tectonics and drainage system evolution in the East Carpathians, Romania

Middle Miocene (Sarmatian) convergence created the fold and thrust belt of the Eastern Carpathians of Romania, which subsequently experienced post-collisional crustal deformation combined with calc-alkaline and alkalic-basaltic volcanism in late Miocene–Quaternary time. This deformation led to the rise of the Cǎlimani–Gurghiu–Harghita volcanic mountains and to the subsidence of the N–S-oriented intramontane Borsec/Bilbor–Gheorgheni–Ciuc and Braşov pull-apart basins, and the E-oriented monocline-related Fǎgǎraş basin. The regional drainage network is the composite of:

(1) Older E-, SE- and S-flowing rivers, which cross the Carpathians, radiate towards the foreland and were probably established during the Middle Miocene (Sarmatian) collision event.

(2) A more recent drainage system related to the contemporaneous development of the volcanoes and intramontaneous basins, which generally drains westward into the Transylvanian Basin since late Miocene time and has been capturing the older river system.

The older river drainage system has also been modified by Late Pliocene–Quaternary folding, thrusting and monoclinal tilting along the Pericarpathian orogenic front and by reactivated transverse high angle basement faults, which cross the Eastern Carpathian foreland.     

Numerical investigation of the influence of extreme hydrodynamic forces on the geometry of structures using OpenFOAM

The main focus of the present study is to numerically examine the effects of tsunami-like-induced hydrodynamic loading applied to free-standing structures with various architectural geometries. To accomplish these goals, the authors employed a multi-phase numerical model utilizing the volume of fluid method in the three-dimensional space. The second objective of the present study is to improve the understanding of hydrodynamic loads on structural components in order to develop practical guidelines for the engineering design of structures located in areas with a high risk of tsunami hazards. In order to evaluate the performance of the numerical model, the results of the simulation are compared with various available experimental data and physical modeling studies. The tsunami-like wave was reproduced via a sudden release of water located in an impounding reservoir located at the upstream part of a flume in the form of a dambreak wave. The shear force exerted by the hydrodynamic force on the square and round structures in the downstream area is estimated to obtain the value of tsunami loading. Finally, the validated numerical model is employed to examine the influence of the structure’s geometry on the hydrodynamic loads exerted on it.