Concluding remarks and perspectives on the evolution and seismic tools activity (ESTA) of the CoRoT community

A first part gives a summary of the main conclusions stemmed from the different comparisons reported in this book. One main conclusion is: with some care in the computations, one is able to obtain frequency differences between different computations which are smaller than required by Corot challenges. This is true for high frequency modes. Small frequency differences are much less easily obtained for low frequencies around the fundamental radial mode frequency. Care here means: having the same physics, same constants of physics, same input stellar parameters, computing models and oscillations with enough self numerical consistent accuracy. The ESTA group has built reference grids of models and associated oscillation frequencies and made them available to the community. In a second part of the present paper, a study case is considered in order to show the need and the use of such reference grids. Finally some perspectives concerning the remaining tasks are suggested.     

Complex coastal change in response to autogenic basin infilling: An example from a sub‐tropical Holocene strandplain

Thick bay‐fill sequences that often culminate in strandplain development serve as important sedimentary archives of land–ocean interaction, although distinguishing between internal and external forcings is an ongoing challenge. This study employs sediment cores, ground‐penetrating radar surveys, radiocarbon dates, palaeogeographic reconstructions and hydrodynamic modelling to explore the role of autogenic processes – notably a reduction in wave energy in response to coastal embayment infilling – in coastal evolution and shoreline morphodynamics. Following a regional 2 to 4 m highstand at ca 5·8 ka, the 75 km² Tijucas Strandplain in southern Brazil built from fluvial sediments deposited into a semi‐enclosed bay. Holocene regressive deposits are underlain by fluvial sands and a Pleistocene transgressive–regressive sequence, and backed by a highstand barrier‐island. The strandplain is immediately underlain by 5 to 16 m of seaward‐thickening, fluvially derived, Holocene‐age, basin‐fill mud. Several trends are observed from the landward (oldest) to the seaward (youngest) sections of the strandplain: (i) the upper shoreface and foreshore become finer and thinner and shift from sand‐dominated to mud‐dominated; (ii) beachface slopes decrease from >11° to ca 7°; and (iii) progradation rates increase from 0·4 to 1·8 m yr^?1. Hydrodynamic modelling demonstrates a correlation between progressive shoaling of Tijucas Bay driven by sea‐level fall and sediment infilling and a decrease in onshore wave‐energy transport from 18 to 4 kW m^?1. The combination of allogenic (sediment supply, falling relative sea‐level and geology) and autogenic (decrease in wave energy due to bay shoaling) processes drove the development of a regressive system with characteristics that are rare, if not unique, in the Holocene and rock records. These findings demonstrate the complexities in architecture styles of highstand and regressive systems tracts. Furthermore, this article highlights the diverse internal and external processes and feedbacks responsible for the development of these intricate marginal marine sedimentary systems.     

Calibration and application of a continuum damage model on the simulation of stone masonry structures: Gondar church as a case study

The conservation and rehabilitation of monuments is a matter of important investigation, and the need for accurate structural analysis, capable of effectively predicting the structural behaviour of this type of constructions, under static and dynamic loads, is increasing. Currently there are numerous computational methods and tools, supported by different theories and strategies with different levels of complexity, computation time and cost which are available to perform such analyses. A complex analysis is not always synonym of a better result and the choice of a method over another depends mostly on the purpose of the analysis. This work aims at evaluating the capacity of a non linear continuum damage model (Faria et al. in Int J Solids Struct 35(14):1533–1558, 1998), originally developed for concrete structures, to simulate the behaviour of stone masonry structures. In particular, the seismic response of an old stone masonry construction, the Gondar church, is analysed considering different levels of geometrical and material complexity. The verification and calibration procedures use the experimental results from tests performed on stone masonry walls at the Laboratory for Earthquake and Structural Engineering of the Faculty of Engineering of Porto University and from other tests found in the bibliography (Vasconcelos in Experimental investigations on the mechanics of stone masonry: Characterization of granites and behaviour of ancient masonry shear walls. PhD Thesis, Universidade do Minho, Guimar?es, Portugal, 2005). The results are compared, assessing the differences and the importance of using complex tools, such as the continuum damage model, to better simulate and understand the global behaviour of such constructions.     

The Milky Way’s stellar disk

A suite of vast stellar surveys mapping the Milky Way, culminating in the Gaia mission, is revolutionizing the empirical information about the distribution and properties of stars in the Galactic stellar disk. We review and lay out what analysis and modeling machinery needs to be in place to test mechanism of disk galaxy evolution and to stringently constrain the Galactic gravitational potential, using such Galactic star-by-star measurements. We stress the crucial role of stellar survey selection functions in any such modeling; and we advocate the utility of viewing the Galactic stellar disk as made up of ‘mono-abundance populations’ (MAPs), both for dynamical modeling and for constraining the Milky Way’s evolutionary processes. We review recent work on the spatial and kinematical distribution of MAPs, and point out how further study of MAPs in the Gaia era should lead to a decisively clearer picture of the Milky Way’s dark-matter distribution and formation history.     

Burying processes carried out by a mobile transversal dunefield, Paracuru County, State of Ceará, Brazil

The migration of dunes and the consequent burying of the city of Paracuru by a transversal dunefield with perpendicular ridges oriented to the dominant windstream have been investigated. Overlapping aerial photographs taken during different flights have been used as a reference. Two sediment transportation directions were identified: the first is fed by the prevailing easterly winds; the second corresponds to the secondary southeasterly winds. With the maintenance of current wind conditions and pluvial precipitation, dunes will bury part of Paracuru town in approximately 120 years. Within this context, the geological evolution model that was applied proved to be satisfactory for the comprehension of sediment transportation mechanisms along the transversal dunes. Considering the prognosis in relation to Paracuru and its urban growth towards the dunefield, it is necessary to continue to study aeolian dynamics, aiming to develop support for the elaboration of future projects directed towards environmental management of the area.     

Adsorption of diclofenac on activated carbon and its hypochlorination in the presence of dissolved organic matter

The nonsteroidal anti-inflammatory drug “diclofenac” is the pharmaceutically active ingredient of several medicines. Since the compound is used in many of its water-soluble salt forms, it is one of the most frequently found pollutants in different parts of the water cycle. Its reaction with sodium hypochlorite was investigated in the presence of humic substances and sandy soil extract at neutral pH at 25 and 250 mg/L initial concentrations. In the lower concentration, the reaction follows a pseudo-first-order kinetics, while at the higher concentration, it is described as the sum of two first-order reactions. These kinetic results, together with the organic chlorine content of the residues, indicated that both chlorination and oxidation took place. The chlorination is significantly faster. The colloids present catalyze the reactions: The clay minerals of soil extract accelerated the chlorination, while the humic acids could work as photocatalysts in the oxidation, while these compounds themselves were chlorinated. The adsorption of diclofenac on activated carbon was enhanced by humic substances, and every isotherm had a breaking point near to 3 mg/L equilibrium concentration (c _e) resulting in two steps. According to the measurements of the zeta potential, the system proved to be relatively stable at this c _e value, but at higher diclofenac concentrations the stability retained only in the presence of the hydrophilic fulvic acid. The results supported the adsorption hypothesis that in the first step the charge transfer interaction while in the second step hydrogen bond formation plays the key role.     

Material characteristics and building technique for the rammed earth wall of the 13th Korean fortress in Ganghwa

This study identifies the technique applied for building the rammed earth wall of the 13th Korean fortress, Ganghwa Jungseong, by analyzing its physical, mineralogical, granulometric, and geochemical characteristics. Furthermore, mutual homogeneities between the rammed earth wall and host rock, top soil, and sub-surface soil collected around the fortress were interpreted. The ground of the rammed earth wall was not created artificially but made via soil preparations containing loamy soils from weathered bedrock. The foundation part was built using various layers of soils having different colors, magnetic susceptibilities, particle sizes, and organic components. In particular, a layer of loamy saprolite was generated to enhance the stability of the foundation and improve ventilation and draining throughout the structure. The body of the wall is composed of silty loam at the bottom and silty loam to loam from the middle to the top. Techniques that alternately harden soils using different particle sizes enable external shock absorption and prevent crack formation owing to temperature changes during winter and summer. The rammed earth wall and the soils around the fortress contained related rock-forming materials had similar magnetic susceptibilities and geochemical characteristics, which indicated that they have a genetically common source. Moreover, the rammed earth wall was built using the soil weathered from the banded gneiss because it was correlated to the banded gneiss constituting the bedrock around the fortress.