Period analysis at high noise level

Analytical expressions are derived for the variances of some types of the periodograms due to normal-distributed noise present in the data. The equivalence of the Jurkevich and the Warner and Robinson methods is proved. The optimum phase cell number of the Warner and Robinson method is given; this number depends on the data length, signal form and noise level. The results are illustrated by numerical examples.     

Aufgaben der Felsmechanik bei neuzeitlichen Tunnelrekonstruktionen

Zusammenfassung Aufgaben der Felsmechanik bei neuzeitlichen Tunnelrekonstruktionen. Für die neuzeitliche Tunnelbauweise müssen neue Erkundungsmethoden mit erweitertem Umfang felsmechanischer Prüfungen angewandt werden. Diese Forderung soll ebenso bei Rekonstruktionen erfüllt werden. Außer den mechanischen Eigenschaften werden auch die innere Spannung im Felsmassiv und in der Ausmauerung, die Mächtigkeit der gelockerten Zone sowie die Injektions- und Verankerungsmöglichkeit bestimmt.

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Summary The Function of Rock Mechanics in Modern Tunnelling. For modern methods of tunnel driving it is necessary to apply new procedures of geological investigations including large-scale rock mechanics tests. This view holds equally for reconstruction projects. In addition to the mechanical properties of the rock masses it is necessary to determine the intrinsic stresses in the rock and in the tunnel lining, the thickness of the inelastic (relaxed) zone around the tunnel, as well as the possibility of grouting and anchoring.

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Résumé Application de la mécanique des roches aux méthodes modernes de construction et de reconstruction des tunnels. Dans la technique moderne des tunnels il est nécessaire d'appliquer de nouvelles méthodes de reconnaissance comportant davantage d'essais de mécanique des roches. La même exigence est valable pour la reconstruction des tunnels. Outre les propriétés mécaniques du massif rocheux, on déterminera aussi les contraintes dans le rocher et dans le revêtement, l'épaisseur de la zone décomprimée et même les possibilités d'injection et de boulonnage.

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Vortrag, gehalten beim XIX. Geomechanik-Kolloquium in Salzburg am 17. Oktober 1969.

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Mit 2 Abbildungen     

Intercomparisons of earth gravity models by means of lumped coefficients: Terms for eccentricity and longitude

The comparisons of the Earth gravity field models by the order of their harmonic coefficients, performed with the basic lumped coefficients (Planet. Space Sci.29, 653, 1981, Paper I) are here extended to cover all harmonic coefficients (both odd and even degree). The lumped coefficients (the “e-terms” and “longitudinal” terms), corresponding to 18 Earth models, are compared mutually (Figs. 2–15). The large differences, observed for various models and orders, are of particular interest: they are gathered into Table 1. The result of Paper I was a little pessimistic. The same is true here: various inhomogeneities, sometimes very large, in the accuracy of the harmonic coefficients must exist—even for low orders. Most of our comments and objections, however, relate to the older Earth models, which have only a historical value now. Our comparisons are only relative ones; an actual test of the accuracy of the models (their calibration) is possible via data with independent status (Kloko?ník, 1982, 1983).     

Current Atmospheric Deposition Loads and Their Trends in the Czech Republic Determined by Mapping the Distribution of Moss Element Contents

Biomonitoring of atmospheric deposition loads of 13, 14 and 35 elements and their compounds through moss analysis was carried out in the Czech Republic (CZ) in 1991, 1995 and 2000, respectively. The last biomonitoring campaign revealed very high contents of typical soil elements and lanthanides in southern Moravia. The variations in current element contents in moss, which can be explained by the action of six factors, were correlated with altitude, with total biennial precipitation, and with the bedrock types in the sampling plots. The element contents in moss samples repeatedly collected from the identical plots showed a steady decrease in atmospheric deposition loads in the CZ in the last decade of the 20th century. The main reasons for this phenomenon are listed. The results of cluster analyses and PCAs have found no substantial changes in the qualitative element composition of atmospheric deposition in CZ in recent years. Isoline maps are presented, which document changes in the distribution of Cd, Pb and S contents in moss in 1995 and 2000. An estimate of absolute deposition loads (g m^–2 year^–1) for given areas of the CZ can be made, using the list of bulk deposition indices.     

Water quality and presence of pesticides in a tropical coastal wetland in southern Mexico

The water quality of the Pozuelos-Murillo lagoon system in southern Mexico was evaluated during three periods between March and October 2002, with particular emphasis on the detection of organochlorine and organophosphorous pesticide residues in water and sediments. Physicochemical and microbiological parameters of water were also measured and integrated in a water quality index (WQI). Multivariate analysis was used to regionalise the lagoon system as a function of the behaviour of all measured parameters. Solid phase micro-extraction followed by gas chromatography (SPME-GC) was used for pesticide analysis. The concentration of phosphorous was found to be higher than that of nitrogenous compounds. This, besides a deficiency in dissolved oxygen and a high organic matter concentration (as COD), reflects eutrophication processes in some areas of the system. Measured levels of faecal coliforms and oils and greases were above the limits established by Mexican law and comparable to the concentrations reported for other highly polluted systems in Mexico. Residues of DDD (2.0 microg L(-1)) in water and DDE (247 ng g(-1)) and endosulfan I (814 ng g(-1)) sediments were detected by SPME-GC. The spatial distribution of these contaminants implies major potential risks because the most polluted sites were found to be those with the highest fishing activity. Although in general the WQI is on acceptable levels (65-80%), some contamination problems are evident.     

Spatial and temporal variability of hard-bottom macrofauna in a disturbed coastal lagoon (Sacca di Goro, Po River Delta, Northwestern Adriatic Sea)

The sessile and mobile macrobenthos on artificial hard bottoms was studied in 12 stations of the Sacca di Goro lagoon, a brackish, highly stressed water basin in the delta of the river Po, open to the Northwestern Adriatic Sea. Three sampling surveys were carried out in June and September 2000 and June 2001 in order to make three types of temporal comparisons: (i) on a seasonal scale, before and after a summer dystrophic event; (ii) on an annual basis, before and after the works of excavation of a canal through the outer sand bank; (iii) on a multiannual scale, comparing the data with those of a survey carried out in 1988. The biocoenoses did not show large fluctuations after a moderately severe summer dystrophic crisis, while the digging of the canal caused clear changes in the macrobenthos community structure after one year. The long-term comparison showed a shift in the community patterns after a decade.     

The k -2 Rupture Model Parametric Study: Example of the 1999 Athens Earthquake

We employ a realistic finite-extent k ^-2 stochastic source model with k-dependent rise time, introduced by Bernard et al. (1996) and extended by Gallovi and Brokeová (2004), to synthesize the strong ground motions in near source distances. For a given magnitude, this rupture model involves a number of free parameters (fault dimensions, slip roughness, maximum rise time, slip velocity function). We study their influence on the peak ground acceleration (PGA) maps (parametric study) for an example of the 1999 Athens earthquake of M _w = 5.9. The observed macroseismic intensities serve us as a rough constraint on the simulated PGA's to find a set of suitable k ^-2 models. These models agree with empirical source scaling relations.     

Investigation of natural and anthropogenic hydrocarbon inputs in sediments using geochemical markers. I. Santos, SP--Brazil

A study on the inputs of organic matter to marine sediments of Santos Bay and Estuary, located in southeastern S?o Paulo State, Brazil, is presented here. The following geochemical markers were identified and quantified: aliphatic hydrocarbons (normal and isoprenoid alkanes), petroleum biomarkers, linear alkylbenzenes (LABs) and polycyclic aromatic hydrocarbons (PAHs). Sediment samples, collected at 15 sites in the bay and surrounding channels, were extracted and analyzed by gas chromatography with flame ionization and mass spectrometer detectors. Total concentrations varied from 0.17 to 107.80 microg g(-1) for aliphatics, from 47.2 to 2560.1 ng g(-1) for petroleum biomarkers, from 16.9 to 430.6 ng g(-1) for LABs and from 79.6 to 15389.1 ng g(-1) for PAHs. Anthropogenic contributions were apparent, indicating the influences of the Cubatao industrial complex, sewage outfalls along the area, the waste deposit of Santos city and storage facilities for petroleum and derivatives, based on the higher concentrations of geochemical markers detected.     

Marine quality assessment by use of benthic species-abundance distributions: a proposed new protocol within the European Union Water Framework Directive

The aim of this study is to develop a new method for classification of marine benthic quality according to the European Union Water Framework Directive. Tolerance values to environmental disturbance were determined in an objective analysis for benthic species along the Swedish west coast by using 4676 samples from 257 stations. Based on a combination of the species tolerance values, abundance and diversity, a benthic quality index (BQI) was calculated for the assessment of environmental status at a particular station. The qualification of BQI was evaluated in relation to known spatial and temporal gradients of disturbance.