Dynamic analysis of column-supported hyperboloidal shells

The dynamic response of hyperboloidal shells on discrete column supports is studied using a curved rotational shell finite element. In this finite element formulation, the displacement field over each element domain is approximated by polynomial functions in which the coefficients of the linear terms correspond to the nodal values of the displacements and the higher order terms vanish at the nodal circles. The stiffness and mass matrices associated with the equations of motion are derived from Hamilton's variational principle and include the effects of transverse shearing deformation and rotatory inertia. Since the formulation, as such, involves a great many degrees of freedom because of the use of higher order displacement functions, the kinematic condensation technique is employed to reduce the order of the dynamic problem The dynamic analysis indicates the importance of realistically modelling the base region of the shell. Studies on a prototype tower indicates that the base flexibility reduces the natural frequencies of the shell and increases the displacements near the base. The magnitude of this reduction, which could be significant, depends primarily on the tangential stiffnesses of the supporting columns and is hardly affected by the thickened ring beam at the base.     

Precise position determination using a Galileo E5 single-frequency receiver

The European Galileo system offers one dedicated signal that is superior to all other signals currently available in space, namely the broadband signal E5. This signal has a bandwidth of at least 51 MHz using an AltBOC modulation. It features a code range noise at centimeter level. Additionally, the impact of multipath effects on this signal is significantly lower compared to all other available GNSS signals. These unique features of Galileo E5 drastically improve the precision of code range measurements and hence enable precise single-frequency positioning. Certain scientific and non-scientific applications in the positioning domain could likely benefit from the exploitation of E5 measurements. A positioning approach based on an additive combination of code range and carrier phase measurements (CPC—“code-plus-carrier”) to eliminate the ionospheric delay could be used to perform precise positioning over long distances. Unfortunately, this derived observable contains the ambiguity term as an additional unknown what normally requires longer observation windows in order to allow sufficient convergence of the ambiguity parameters. For this reason, a rapid convergence algorithm based on Kalman filtering was implemented in addition to the conventional CPC approach that is also discussed. The CPC-based results yield a positioning precision of 2–5 cm after a convergence time of about 3 h. The rapid convergence filter allows fixing the ambiguity terms within a few minutes, and the obtained position results are at the sub-decimeter level. Regarding one selected test, real data from Galileo experimental satellite GIOVE A were used in order to confirm our assumptions. However, since the current Galileo constellation is not sufficient for real-world positioning trials yet, all major results are based on simulated data.     

Paleo-stratigraphic permeability anisotropy controls supergene mimetic martite goethite deposits

The Hamersley Basin in Western Australia is one of the world's largest iron ore-producing regions, hosting two types of ore in banded iron formations: the high-grade martite-microplaty haematite and the supergene martite-goethite ores. With the high-grade ores almost entirely mined in the last decade, the supergene ores have more recently become the dominant resource of interest. Consequently, understanding the genesis of these martite-goethite deposits is a critical step for exploration. Yet, although various models exist, there is still no consensus on how these mineral resources formed, complicating the prediction of resource volume and location. Here, we show that the paleo-stratigraphic permeability anisotropy (with higher permeability along strata than across) controls the supergene mimetic enrichment transport process and, subsequently, the mineralisation distribution. We introduce a flow model that implicitly represents strata with a potential function that orients the permeability tensor accurately. The numerical solver uses automatic mesh adaptivity to deliver robust solutions. By accurately reproducing the mineralisation patterns in specific deposits, we identify and quantify the paleo-water table level and permeability anisotropy ratio as the two main controlling parameters for the mineralisation distribution. These insights provide new timing constraints for the mineralisation and the physical process of iron enrichment, suggesting much more potential mineralisation volume in the paleo-reconstructed zones than previously anticipated. These flow models allow us to draw geological conclusions with few a priori assumptions required for the genetic model in which the transport component is dominant. The predictive power of this methodology will allow targeted drilling to narrow down the prospective areas and lower exploration costs. Furthermore, the methodology's generality applies to other commodities in sedimentary basins involving supergene processes and will improve our understanding of various genetic models.     

Late cretaceous Arman’ flora of Magadan oblast: Paleoclimatic interpretation

The Arman’ flora belongs to the formation of the same name in the Arman’ River basin and Nel’khandzha-Khasyn interfluve. It includes about 80 fossil plant species. The similarity of this flora to the reliably dated fossil floras of northwestern Kamchatka and the Pekul’nei Range dates it to being Turonian and Coniacian in age, which is corroborated by isotopic (U-Pb and ⁴⁰Ar/³⁹Ar) dating of the plant-bearing layers. The CLAMP method is used to estimate quantitative climatic variables, according to which the Arman’ flora existed in a temperate humid climate with warm summers and mild winters. This climate is especially similar to the conditions reconstructed from fossil plants of the Turonian Penzhina flora and the Coniacian Kaivayam and Tylpegyrgynai floras of Northeast Asia.     

Classification and regression tree theory application for assessment of building damage caused by surface deformation

A framework of applying the classification and regression tree theory (CART) for assessing the concrete building damage, caused by surface deformation, is proposed. The prognosis methods used for approximated building hazard estimation caused by continuous deformation are unsatisfactory. Variable local soil condition, changing intensity of the continuous deformation and variable resistance of the concrete buildings require the prognosis method adapted to the local condition. Terrains intensely induced by surface deformation are build-up with hundreds of building, so the method of their hazard estimation needs to be approximated and relatively fast. Therefore, promising might be addressing problems of reliable building damage risk assessment by application of classification and regression tree. The presented method based on the classification and regression tree theory enables to establish the most significant risk factors causing the building damage. Chosen risk factors underlie foundation for the concrete building damage prognosis method, which was caused by the surface continuous deformation. The established method enabled to assess the severity of building damage and was adapted to the local condition. High accuracy of shown approach is validated based on the independent data set of the buildings from the similar region. The research presented introduces the CART to determination of the risk of building damage with the emphasis on the grade of the building damage. Since presented method bases on the observations of the damages from the previous subsidence, the method might be applied to any local condition, where the previous subsidence is known.     

The Metamorphic Evolution and Tectonic Significance of the Sumdo High and Ultrahigh Pressure Metamorphic Terrane, Central-South Lhasa Block, Tibet

Asthemaintectoniccomponentofthe Himalayan–Tibetan orogen,the Lhasa terrane has received much attention as it records the entire history of the orogeny.The occurrence of high pressure eclogite in the Sumdo complex in central Lhasa terrane has a significant importance on the understanding of the Paleo-Tethys subduction and plate itineration processes in this area.The petrological,geochemical and geochronological data of eclogite and associated blueschist and garnet-bearing mica schist from Sumdo,Jilang and Bailang area have been briefly reviewed to explore the origin and metamorphic evolution of this suture.Eclogites from the Sumdo complex have experienced low temperature,high pressure to ultrahigh pressure metamorphism,revealing a fastsubduction and exhumation process in a typical oceanic subduction zone.The large P-T range between different eclogites in the literature may be affected by the big error of unappropriated using geothermobarometry and may also because of slices of subducted blocks derived from different depths juxtapose together during exhumation.By summarizing the U-Pb,Lu-Hf and Sm-Nd ages of eclogites,the eclogite facies metamorphism is likely to occur in early Triassic during 245-225 Ma,but not the previously accepted late Permian at ca.260 Ma by the reinterpretation of the former geochronological data from literature.The opening of Paleo-Tethys Ocean between the Lhasa terrane initiate prior to ca.280 Ma and ultimate closure to integrate the Lhasa terrane was no earlier than225 Ma and may triggered by the initial subduction of Bangong-Nujiang Tethys Ocean in the north.     

Twentieth century variability of surface humidity as the climate change indicator in Kraków (Southern Poland)

Air humidity is an element that plays an important role among meteorological processes within the atmosphere; however, the variety of humidity indices makes the global view of air moisture changes difficult. Long-term variability of air humidity in Kraków was examined by time-series (1901–2000) analysis of vapour pressure and saturation deficit values and their characteristic days with the background of temperature and saturated vapour pressure changes. Long-term variability of air humidity in Kraków has been visible above all in variations of saturation deficit. It should be connected with the contemporary temperature growth and the city development as the atmospheric water vapour content (described by vapour pressure) becomes relatively stable (with no significant tendencies). The parameter showed well-marked trends over the examined period. The growth of saturation deficit values predominated in the warm half of a year (above all in August: an increase in SD value by 3.0 hPa per century). Apart from atmospheric circulation variability, gradual rise in the number of inhabitants and higher development density contributed to the decline in the city’s air humidity; however, the causes of changes in air humidity should be also attributed to natural factors, mainly to variation of air circulation reinforced by the operation of anthropogenic factors. Using air humidity as the indicator, the results that confirm climatic fluctuations in central Europe in the twentieth century obtained earlier were verified and some new aspects of present climate change were given.