Investigating the Economic Performance of Tunnel Excavation in Iran: 1998–2013

Nowadays, the world is witnessing the ever increasing need of Tunnel excavation due to their unique features and the kind of human applied plans. This has led to increase in demand of excavating this engineering factor. Tunnel excavation process faces a lot of challenges due to environmental and technological complexities which causes the economic evaluation and investigation of this project to be difficult. It is tried to develop the proposed model with regard to efficiency concept in order to evaluate and investigate the efficiency of relative economic performance of Tunnel excavation projects and turn to its modeling and implementing by data envelopment analysis and Fuzzy DEMATEL techniques. The results in Iran showed that the proposed model can turn to investigation and evaluation of economic efficiency of Tunnel excavation by considering two optimistic (ideal) and pessimistic perspectives such that the Tunnel excavation process of “Karaj water transition” and “Cheshmelangan water transition” among 12 rock Tunnel excavation projects of Iran in the time period of 1998–2013 were respectively introduced as the most efficient and the most inefficient rock Tunnel excavation projects.     

The Loewenstein rule: the increase in electron kinetic energy as the reason for instability of Al–O–Al linkage in aluminosilicate zeolites

Problem of Al–O–Al linkage in aluminosilicate materials or Al-avoidance is discussed for two zeolite structures (phillipsite and brewsterite) exchanged with Mg²⁺ cations. All models are fully optimized at periodic Hartree–Fock and hybrid density functional theory levels (the CRYSTAL code). Their properties are then calculated at the periodic level with the same basis sets. The reasons for the instability of the zeolite structures including the Al–O–Al moieties are interpreted on the basis of cell energy decomposition. This destabilization comes from an increase in kinetic energy if the Al–O(Mg)–Al moieties are present in zeolites. This effect is discussed in parallel with already known variational evidences in favor of dominating role of kinetic energy for stability of molecular systems.     

The character of scaling earthquake source spectra for Kamchatka in the 3.5–6.5 magnitude range

The properties of the source spectra of local shallow-focus earthquakes on Kamchatka in the range of magnitudes M _w = 3.5–6.5 are studied using 460 records of S-waves obtained at the PET station. The family of average source spectra is constructed; the spectra are used to study the relationship between M _w and the key quasi-dimensionless source parameters: stress drop Δσ and apparent stress σ_a. It is found that the parameter Δσ is almost stable, while σ_a grows steadily as the magnitude M _w increases, indicating that the similarity is violated. It is known that at sufficiently large M _w the similarity hypothesis is approximately valid: both parameters Δσ and σ_a do not show any noticeable magnitude dependence. It has been established that M _w ≈ 5.7 is the threshold value of the magnitude when the change in regimes described occurs for the conditions on Kamchatka.     

The application of biogeochemistry for gold exploration in the Masjed–Daghi, Julfa, NW Iran

The aims of present study are investigation of endemic plants at Masjed–Daghi area introducing hyperaccumulator and indicator plants for Au, Ag, As, Cu, Mo, Hg, Re, Sb, and Te mineralization and also describe the biogeochemical response pattern over a known Au–Cu mineralized site. The Masjed–Daghi prospecting area is covered by Eocene flysch, andesite, trachyandesite, dacite, rhyodacite, Oligocene agglomerate, and Quaternary deposits. Previous researches reported copper porphyry mineralization and related epithermal gold veins in this area. This study presents that plants with high metal intake enabled us to obtain invaluable information about natural concentrations of chemical elements in the substrate and to recognize new potential areas for mineral prospecting. Stachys inflata has biological absorption coefficient mean exceeding or near hyperaccumulating criterion >1 for most of the elements investigated then could be as a hyperaccumulator. The indicator values belong to S. inflata, Artemisia sp., Salvia sp., Astragalus sp., Peganum harmala, Moltkia coerulea, and Cousinia sp.     

The Contemporary Seismic Deficit in the Kuril–Kamchatka Subduction Zone

Doklady Earth Sciences - Based on an analysis of seismicity for the period of 1900–2018, the seismic potential of the Kuril–Kamchatka subduction zone is estimated, and the geometry of...     

The hydrocarbon-generation potential of the Domanik rocks in the Volga–Ural petroliferous basin

The factors that are responsible for the formation of the hydrocarbon-generation potential and its occurrence in the Devonian carbonate sequences (Domanik Formation) of the Volga–Ural petroliferous basin are considered. The rocks of this formation are characterized by a high generation potential that is sufficient for the formation of large oil and gas accumulations. The highly carbonaceous deposits lack reservoirs.     

The role of water resources in the evolution of the Israeli–Lebanese border

The current location of the border between Lebanon and Palestine, today's Israel, is a product of various competing forces. The Zionist Organization aspired to include the entire Galilee region up to the lower reaches of the Litani River (also known as the Kassimiyah River) within Palestine. The river itself was the desired northern border of the country. The Zionists supported their position by employing instrumental arguments that were largely related to the availability of water resources. On the other hand, residents of the upper Galilee, today's southern Lebanon, demanded that they be included with Lebanon. They used their trade links with Beirut, and cultural and familial ties with other parts of Lebanon to support their position. These instrumental and expressive arguments appear to have assisted in the demarcation of the border between Lebanon and Palestine. Currently, access to the water resources, not necessarily control over them, is likely to influence negotiations between Israel and Lebanon over the future of the Israeli-occupied security zone in southern Lebanon.     

The first Lu–Hf zircon isotope data for gabbro–diorite–tonalite associations of the Urals

Doklady Earth Sciences - The Lu–Hf isotope systematics of zircon from the gabbro–plagiogranite association (gabbro, diorite, tonalite, and plagiogranite), which is one of the most...     

Anisotropic Scattering of the Radio Emission of the Pulsar B0833–45 in the Vela Supernova Remnant

Very Long Baseline Interferometry (VLBI) observations of the pulsar B0833–45 have been carried out as part of the scientific program of the RadioAstron mission. Ground support was provided by the Long Baseline Array, which includes radio telescopes in Australia and other countries in the southern hemisphere. The VLBI observations of the pulsar are analyzed in order to derive the parameters characterizing the scattering of the pulsar radio emission: the angular size of the scattering disk, the spatial scale of the diffraction pattern, the drift velocity of this pattern relative to the observer, the pulse scattering time scale, and the characteristic scintillation time and frequency scales, as well as the index of the electrondensity fluctuation spectrum. Comparison of these values with the predictions of the theory of scattering on a thin screen enables the determination of the position of the effective screen along the line of sight. Estimates made using various methods give distances to the screen from the observer of 0.79 to 0.87 times the total distance to the pulsar. Although the position of the screen is beyond the boundary of the Vela supernova remnant, this object may play the dominant role in the scattering. The scattering disk is an ellipse with a 2:1 axis ratio and with the inferred position angle of the major axis being ≈ 50°, based on the changes in the visibility-function amplitude for various orientations of the projected baseline. This conclusion is supported by the shape of the visibility-function amplitude as a function of the delay.

     

The Apparent Polar Wander Path for South America during the Permian–Triassic

Many of the controversies that arise in global reconstructions for Permian–Triassic time could be resolved by taking into account the large latitudinal and counter-clockwise movement of Gondwana during that interval of time. The proper trace of the apparent polar wander curve should differentiate one position for the Early Permian, another position for the Late Permian and yet another for the Triassic. By doing so and comparing the Apparent Polar Wander Paths (APWP) of South America and Africa it is easy to see that both curves have the same shape, therefore it is possible to arrive at a good fit between them, which previous analyses were unable to achieve. This new proposed Permian–Triassic track of the APWP reveals a hook not hitherto recognized that should be accounted for in global reconstructions.     

Phytoplankton,protozooplankton and nutrient dynamics in the Bornholm Basin (Baltic Sea) in 2002–2003 during the German GLOBEC Project

From March 2002 to until April 2003 we investigated the seasonal nutrient and phytoplankton dynamics in the central Bornholm Basin (Baltic Sea) within the framework of the German GLOBEC Project. We choose a nested approach consisting of vertical fluorescence profiles, phytoplankton counts and nutrient analyses. The Fluoroprobe (MultiProbe, BBE Moldaenke) is capable of distinguishing four algal groups (Cryptophyceae, Cyanophyceae, Chlorophyceae, Bacillariophyceae + Dinophyceae). Winter nutrient concentrations were about 5 μM NO₃ and 0.5 μM PO₄ in the central Basin. The spring phytoplankton bloom was dominated by the diatom Skeletonema sp. and reached a maximum of about 270 μg C/l before the onset of the seasonal stratification. Protozooplankton was dominated by the Mesodinium rubrum (a phototrophic ciliate = Myrionecta rubra) and reached a maximum biomass of about 200–300 μg C/l about 2 weeks after the demise of the diatom spring bloom. During summer, the water column was stratified and a subsurface maximum developed near the thermocline consisting of Bacillariophyceae, Cryptophycea and other phototrophic flagellates. Phytoplankton and protozooplankton biomass was generally low. Nutrient concentrations point towards a nitrogen limitation during this period. The stratification period ended during September and surface nutrient concentrations increased again. Protozooplankton reached a second maximum during September. With the Fluoroprobe small scale structures in the plankton community could be detected like a subsurface Cryptophyceae maximum near the thermocline that however, could not be confirmed by cell counts. The chlorophyll a estimate of the Fluoroprobe was in good agreement with the phytoplankton biomass estimated from counts. We conclude that only by combining modern sensing technology with microscopy, the small-scale dynamics and taxonomic spectrum of the plankton can be fully captured.     

The Geochemical Zoning of the Peschanka Porphyry–Epithermal System in the West of the Chukchi Peninsula

The results of chemical analyses and the data on core samples for 266 drill holes were used to identify the geochemical zoning of the Peschanka porphyry–epithermal system. A 3D model of geochemical zoning was developed using factor analysis and GIS technologies to represent the spatial distribution of elemental associations and mineral assemblages. The lateral and longitudinal zoning patterns are described. The AgPbZn: CuAuMo ratio is suggested as an indicator of vertical zoning that allows to evaluate the erosion level of porphyry copper stockworks.     

The unconformity-related palaeokarst in the uppermost Ediacaran carbonate rocks in the northwestern Tarim Block,NW China: implication for sedimentary evolution during the Ediacaran–Cambrian transition

ABSTRACT

The unconformity between the Ediacaran and Cambrian and its associated palaeokarst was well preserved within the Aksu area of the northwestern margin of the Tarim Block and provides new insights into the sedimentary evolution of the Tarim Basin during the Ediacaran–Cambrian transition. In this contribution, the typical palaeokarst features in the uppermost Ediacaran dolostones at nine outcrops in the Aksu area were documented, including palaeocaves, cave-sediment infills, solution vugs, and pores. Large-scale collapsed breccia assemblages in palaeocaves indicate that strong karstification had occurred in the south belt from the Xiaoerburak to Kule sections. Karst characterized by small-scale caves and solution vugs at the Chigebrak and Kakebashi sections suggests that the karstification in the north belt was not stronger than that in the south belt. Whereas sparse solution pores and small vugs can only be observed at the Sugetbrak and Yuermeinak sections, demonstrating that the karstification was weak in the middle belt. Combined with the thickness of sediments in the base of the Cambrian which subsequently overlay on the Ediacaran–Cambrian unconformity, it is speculated that the palaeo-upland was probably located in the middle belt from the Sugetbrak to Yuermeinak sections and the slope was developed in the south and north belts during the Ediacaran–Cambrian transition. The palaeokarst documented in the uppermost Ediacaran dolostones in the Aksu area illustrates an important sedimentary hiatus of the Tarim Block during the Ediacaran–Cambrian transition, which might be due to the sea-level fall at the end of the Ediacaran.     

The use of press data in the development of a database for rainfall-induced landslides in Tegucigalpa,Honduras, 1980–2005

The capital city of Honduras, Tegucigalpa, suffers from the occurrence of destructive landslides on a yearly basis. During the rainy season, damages to infrastructure as well as injuries, casualties and homeless individuals resulting from landslides are reported in the press. This paper presents the development of a database for rainfall-induced landslides for the period 1980–2005, based on the news reported by two local newspapers. The editions comprehended during the study period have been scrutinized, and articles focusing on landslides, tropical storms, hurricanes, floods and vulnerability of the city have been collected. The interpretation of these archives has allowed the compilation of valuable data of approximately 400 landslides. The analyses of monthly and annual precipitation during the study period show how extreme rainfall events like Hurricane Mitch in October of 1998 have significantly contributed to the initiation of landslides. In addition, the assessment of the slums and neighborhoods affected by landslides during the study period reveals an evident link between the social and physical vulnerability of Tegucigalpa. In order to estimate the reliability of this press-based database, the set of landslides that have been reported as a result of Hurricane Mitch in the press archives has been compared with two inventories based on the interpretation of aerial photographs taken in 1999 and 2001. It is shown that the analysis of the landslide damage left after the hurricane can be enriched with the detailed temporal data provided in the archives and the precise location of these events determined by the aerial photographs. Despite the difficulties faced in the compilation of this database, a good comprehension of the temporal and spatial distribution of landslides in Tegucigalpa has been achieved.     

The Coulomb–Mohr Law and the Change in the Stress–Strain State of a Landslide Prone Mass

Doklady Earth Sciences - The stresses at the points of the ground mass are determined and distributed according to the Coulomb–Mohr law in the main stresses, under compression conditions. The...     

Geochemical modelling of CO2–water–rock interactions in a potential storage formation of the North German sedimentary basin

The lower Triassic/Bunter sandstone and lower Jurassic/Rhät formations of the Northern Germany sedimentary basin constitute feasible reservoirs for the storage of CO₂ from combustion of fossil fuels or industrial production processes. This study presents analyses of geochemical interactions between CO₂, formation fluid and rock of these potential reservoirs using geochemical modelling in order to assess the short and long term impact of CO₂ sequestration. Batch equilibrium modelling was performed first for assessing the consistency of fluid and mineralogy field data and for identifying potential secondary minerals under the influence of injected CO₂. Inclusion of reaction kinetics in the batch models allowed an observation of reaction paths and to estimate the time frame of geochemical reactions. Finally, one-dimensional equilibrium reactive transport modelling was used in order to investigate the direction of reactions under conditions of fluid flow and mass transport and to quantify feedbacks of reactions on transport processes.Results of the simulations performed show that dawsonite may act as the main CO₂ storage mineral in both formations, while the carbonates calcite and dolomite dissolve over time. Also, changes in porosity and permeability are significant in the equilibrium reactive transport simulations. The time scale of kinetically controlled reactions observed in the kinetic batch modeling, however, suggests that CO₂ mineral trapping in both formations requires very long time frames, and hence other mechanisms such as structural or solubility trapping seem to be more relevant within the injection or early post-injection phase for the studied formations.     

The Ureg Nuur Pt-bearing volcanoplutonic picrite–basalt association in the Mongolian Altay as evidence for a Cambrian–Ordovician Large Igneous Province

The paper discusses geological, mineralogical, petrographic, and geochemical data on the Ureg Nuur volcanoplutonic association of high-Mg volcanic and subvolcanic rocks located among Vendian–Cambrian accretionary structures in the Mongolian Altay. These rocks have a high potassium alkalinity (K₂O/Na₂O up to 1.2), are enriched in LILE and Sr, and have negative Zr–Hf and Nb anomalies in multielement spectra; this confirms the suprasubduction type of the source of melts. The geological setting and established age (512.4 ± 6.1 Ma, ³⁹Ar–⁴⁰Ar dating of biotite phenocrysts) evidence picritic magmatism at the accretionary stage of the development of the Altay fragment of the Paleoasian ocean. This indicates a large igneous province related to a mantle plume.     

The “coal–bauxite–iron” structure in the ore-bearing rock series as a prospecting indicator for southeastern Guizhou bauxite mines

Bauxite deposits in southeastern Guizhou occur in the lower Permian Liangshan Formation. The rock series bearing the sedimentary bauxite exhibit a typical “coal–bauxite–iron” structure, in which the lower part consists of bauxitic shale intercalated with siderite concretions, the middle part consists of bauxitic rock intercalated with multilayer lenticular or earthy bauxite, and the upper part consists of carbonaceous shales and sandstones intercalated with coal seams. The paralic, coastal and paludal depositional environments at one time had a stable tectonic setting. By studying the elemental geochemistry of the ore-bearing rock series, it can be seen that the common presence of the “coal–bauxite–iron” structure has resulted from (1) the extensive desilication and iron depletion during the formation of the sedimentary bauxite due to the varying physical and chemical environment, and (2) the sufficient supply of organic matter by the external environment. Such geological anomalies that resulted from the physical and chemical changes during the formation of the layered structure in the ore-bearing rock series can serve as a mineralization indicator in prospecting for new deposits.