Constant-phase element identification in conductivity sensors using a single square wave

This paper proposes a novel method to measure the electrical conductivity of solutions in the time domain by using a single square-wave current and two titanium electrodes. This method allows us to determine both the conductivity (σ) of the solution and the two parameters of the constant-phase element (CPE) due to the electrodes. Experimental results show that the proposed method achieves conductivity measurement ranges close to those obtained with platinum probes or tetrapolar measurements, which are more expensive, and provides information about electrode condition.Peer Reviewe

Measurement of three independent components in impedance sensors using a single square wave

Two-wire impedance-based sensors involving electrolytes add the impedance of the electrodes to the electrical impedance of the medium to measure. An equivalent circuit for the measured impedance is a resistance in series with the parallel combination of another resistance and a capacitance. If the two electrodes are modelled by equal impedances, the equivalent circuit for the complete set up consists of three impedance components, which can be determined from three independent measurements. This paper describes a novel method to obtain those three components using a single square wave voltage (period 2T) instead of several sine waves and provides the equations to calculate their value from the three current intensity amplitudes measured at T/8, 3T/8 and 5T/8. Other measurement times would need different equations, but the same procedure applies. Anyway, the proposed method keeps the advantages of synchronous detection and relies on analytical solutions instead of the customary curve fitting procedures. Computer simulation and experimental results obtained by measuring the conductivity of known electrolyte samples validate the proposed methodPeer Reviewe

Extreme wave events in the southeastern Iberia coast: Blocks and megablocks as an indicator of tsunamis or extreme storms

Whilst the SW coast of the Iberian Peninsula has a significant record of extreme wave events (EWE), mostly associated with tsunamis, the Mediterranean coast offers a smaller record of these events, although some historical tsunamis with limited impact have been cited on the coast. In general, these studies have been based on the geological record of detrital sequences of sands and silts. In this case, we have focused on the study of coastal deposits of blocks and megablocks in Cope, Murcia (SE of Iberian Peninsula). Here, blocks greater than 1 m and located up to 4 masl were generated by an EWE associated to either a tsunamis or great storm. An unmanned aerial vehicle (drone) has been utilized to perform aerial photogrammetry, which complemented terrestrial photogrammetry of higher resolution.This has been processed to develop a 3D model of the terrain and obtain the dimensional and spatial parameters of these blocks. Different models have been used to calculate potential tsunami wave heights and scale of storms capable of generating such deposits (Nott, 2003; Engel and May, 2012). The results confirm the process of generating force required to generate the block ridges at this site

Archaeological survey in the Blue Nile area, Central Sudan. Prospección arqueológica en el área del Nilo Azul, Sudán Central

Se presentan los resultados de una prospección intensiva del área de Wadi Soba-el-Hasib al este de Jartum en la orilla oriental del Nilo Azul y una exploración del Nilo Azul aguas arriba hasta Singa. El objetivo principal fueron losrestos prehistóricos, con un 80% de yacimientos mesolíticos (EarlyKhartoum), siendo el resto neolítico(Shaheinab-Jebel Moya) junto a escasos restos paleolíticos. Porprimera vez se han registrado yacimientosimportantes del Neolítico Final en el Sudán Central, siempreen áreas lejanas al Nilo de la Butana y laGezira. Se han aplicado métodos estadísticos multivariantes a los procesos de formación, seriación cerámica ymodelos de asentamiento. Se advierte elpaso primero de una explotación acuática por grupos móviles a unaconcentración demográfica decazadores-pastores de sabana, que luego adoptan una economía móvil contúmulos funerarios comoúnico resto arqueológico hasta la época moderna.The results are presented of an intensive survey of the Wadi Soba-el-Hasib area east of Khartoum on the east bank of the Blue Nile and the exploration of the Blue Nile Basin upstream to Singa. The survey focused mainly on the Prehistoric sites, with the Mesolithic period (Early Khartoum) as the mostly represented with more than 80% of the discovered sites, the Neolithic sites (Shaheinab-Jebel Moya) making up most of the remainder 20%. Very few Palaeolithic sites were recorded. Late Neolithic sites of large size have been found for the first time in the Central Sudan, all of them located away from the Blue Nile in the Butana and Gezira plains. Site structure and formation processes, ceramic seriation and settlement patterns have been analysed applying statistical multivariate methods to the survey quantitative data. Some historical trends have been noticed. The first is the change from a Nilewadi aquatic exploitation by small mobile groups towards demographic concentration of near-sedentary savanna hunting herding populations. During the Late Neolithic period the groups adopted a mobile economy and their only archaeological record thereafter are the burial tumuli fields up to the Christian and Islamic periods

Diccionario biográfico de Colegiales Mayores Españoles. 1560-1650

Ponencia presentada en el Instituto de Investigaciones de Historia del Derecho -INHIDE- (Buenos Aires) el día 2 de septiembre de 2021

Presence of boulders associated with an extreme wave event in the western Mediterranean (Cape Cope, Murcia, Spain): Possible evidence of a tsunami

The region of Murcia, in the southeast of the Iberian Peninsula, experiences moderate tectonic activity, with earthquakes of up to 6.2–6.9 Mw recorded. Even with seismic activity of this scale there is no geological or instrumental record of tsunamis affecting the area. The presence at Cape Cope, Murcia of a ridge of metre-sized imbricated boulders (comprised of Upper Pleistocene sediments) reaching a height of up to 4m above sea level, indicates that there has been an extreme wave event in the area during the Holocene. Through studying the wave conditions generated during large storms in this area, the boulder ridges appear to have been caused by extreme waves associated with a seismic event, as a tsunami

Improving the coastal record of tsunamis in the ESI-07 Scale : Tsunami Environmental Effects Scale (TEE-16 Scale)

This paper discusses possibilities to improve the Environmental Seismic Intensity Scale (ESI-07 scale), a scale based on the effects of earthquakes in the environment. This scale comprises twelve intensity degrees and considers primary and secondary effects, one of them the occurrence of tsunamis. Terminology and physical tsunami parameters corresponding to different intensity levels are often misleading and confusing. The present work proposes: i) a revised and updated catalogue of environmental and geological effects of tsunamis, gathering all the available information on Tsunami Environmental Effects (TEEs) produced by recent earthquake-tsunamis; ii) a specific intensity scale (TEE-16) for the effects of tsunamis in the natural environment at coastal areas. The proposed scale could be used in future tsunami events and, in historic and paleo-tsunami studies. The new TEE-16 scale incorporates the size specific parameters already considered in the ESI-07 scale, such as wave height, run-up and inland extension of inundation, and a comprehensive and more accurate terminology that covers all the different intensity levels identifiable in the geological record (intensities VI-XII). The TEE-16 scale integrates the description and quantification of the potential sedimentary and erosional features (beach scours, transported boulders and classical tsunamites) derived from different tsunami events at diverse coastal environments (e.g. beaches, estuaries, rocky cliffs,). This new approach represents an innovative advance in relation to the tsunami descriptions provided by the ESI-07 scale, and allows the full application of the proposed scale in paleoseismological studies. The analysis of the revised and updated tsunami environmental damage suggests that local intensities recorded in coastal areas do not correlate well with the TEE-16 intensity (normally higher), but shows a good correlation with the earthquake magnitude (Mw). Tsunamis generated by earthquakes can then be considered efficient processes in the direct transference of the "energy" released by offshore seismogenic sources to the nearest coastal areas, even over distances of hundreds of kilometres (>200km). This scale, as the previous ones, is independent of the earthquake type (i.e. style of faulting) and only focuses on the environmental effects triggered by tsunamis of seismic origin

Habitat Constraints in Epikarstic Waters of an Iberian Peninsula Cave System

14 páginas, 6 figuras, 11 tables et al..The epikarstic waters of a restricted sector of the Ojo Guareña cave (north Iberian Peninsula) were investigated to characterize the physico-chemical variation in an annual cycle, to improve the scarce knowledge of the aquatic cave fauna on the Iberian Peninsula, to look for distribution patterns of species per habitat along the annual cycle, and to search for the environmental basis (either physico- or hydro-geochemical) that could explain species distribution in the epikarst. The habitats studied included all puddles and gours present in the sector selected making a total of 51 chemical and 42 biological samples for the entire cycle. The waters show no appreciable contaminationand exhibit small chemical variations throughout the year which are patently affected by external weather conditions. The 53 taxa found belong to ten higher taxonomic groups (Oligochaeta, Turbellaria, Mollusca, Copepoda, Ostracoda, Isopoda, Bathynellacea, Tardigrada, Acarina and Cnidaria), and consist mainly of crustacea with a total of 27 species. Fourteen species were stygobionts (belonging to ten genera), nine of which are new to science and ten of which are endemic. Cave pools that appeared to be more stable in terms of water volume and mineralization, had a lower pCO2 and were carbonate oversaturated, harboured the greatest number of taxa. It is these pools that can maintain strictly cave dwelling species. Pools with lower levels of mineralization and greater water volume fluctuations had a lower diversity of fauna and in general lacked stygobiotic species.Projects PASCALIS EVK2-CT-2001-00121; Convenio Junta de Castilla y León-CSIC (2002-2004) and BTE2002-04492-C02-02.Peer reviewe