Solution of the downward continuation problem by collocation

Summary The modern satellite techniques enable to measure the gravity acceleration in space. The downward continuation of this measurements to the earth's surface is by the closed theory practically impossible. Using the method of collocation we can estimate the values of Δ g in the limited region underneath the observation with a little loss of accuracy. Results of some numerical tests for elevation of 300 km are presented.     

Individual and Synergistic Effects of Metronidazole,Amoxicillin, and Ciprofloxacin on Methane Fermentation with Sewage Sludge

Methane fermentation is widely used to dispose of sewage sludge at wastewater treatment plants (WWTPs), due to production of renewable energy in the form of biogas. Antibiotics present in wastewater may accumulate in a sewage sludge. The aim of the present study is to investigate the impact of three antibiotics from different classes in three different doses on methane production from sewage sludge. For this purpose, metronidazole (MET), amoxicillin (AMO), and ciprofloxacin (CIP) are individually added to anaerobic reactors with sewage sludge collected from municipal WWTP. The antibiotics’ highest concentration (1024 mg kg^?1 of AMO; 512 mg kg^?1 of MET and CIP) lowers methane production and methane content in biogas. MET exerts the most marked effect and lowers methane production to 36.8 ± 3.7 mL CH₄ kg^?1 volatile solids. Tested antibiotics probably inhibit methanogenic archaea, which results in volatile fatty acids (VFAs) accumulation. Addition of MET results in accumulation of many kinds of VFAs with the highest concentration of acetic acid (17.52 ± 1.85 g L^?1). The addition of of AMO results in accumulation of butyric acid only (253.00 ± 15.89 g L^?1). However, addition of CIP results in accumulation of mainly acetic acid (7.58 ± 0.82 g L^?1) and isovaleric acid (2.01 ± 0.41 g L^?1). Next, synergistic effect of these antibiotics in a low concentration of 16 mg kg^?1 of AMO, 8 mg kg^?1 of MET, and 2 mg kg^?1 of CIP is measured in semi‐continuous conditions and causes inbibition of methane production and accumulation of VFAs.     

Time changes of the potential Love tidal parameters k2 and k3

The planet Earth is continuously changing in time, so there are phenomena that require continuous observation, including tidal parameters. The main goal of this study is to analyze time changes of the Love potential tidal parameters. This paper concerns an analysis of the estimated Love numbers k for the second and the third degree tides (numbers k₂ and k₃), associated with the tide variations of the satellite motion. The measured data used for determining the parameters k₂, k₃ were conducted within the period of January 1, 2014 until July 1, 2016 by LAGEOS-1 and LAGEOS-2 satellites. The results were compared with our previous determination of these parameters from LAGEOS data during the period from January 1, 2005 until July 1, 2007 to examine whether any systematic differences and time evolution occur. The adjusted values for k₂ equalling 0.29842 ± 0.00008 and k₃ equalling 0.0901 ± 0.0034 are discussed and compared with the nominal values given in International Earth Rotation and Reference Systems Service standards. The differences between the k₂ and k₃ values obtained for the time interval 2005.0–2007.5 and the results for 2014.0–2016.5 interval are –0.00288 for k₂ and 0.0042 for k₃. The obtained differences in the k₂ and k₃ values may indicate their evolution in time.     

Refinement of the Hardening Soil model within the small strain range

Acta Geotechnica - The popularity of the elasto-plastic Hardening Soil (HS) model is based on simple parameter identification from standard testing and empirical formulas. The HS model is...     

Computation of nitrate concentrations in turbid coastal waters using an in situ ultraviolet spectrophotometer

In order to investigate biogeochemical cycling and dynamics of nutrients, measurement capabilities with sufficient spatial and temporal resolution are required. New ultraviolet-based methods and instrumentation for in situ determination of nitrate provide a powerful tool for these purposes. Here, we present a full dataset obtained by an UV-based process spectrophotometer (ProPS) during a cruise in 2008 in the south-eastern North Sea. Due to highly turbid conditions and mixing water masses, an improved calculation algorithm was performed on the UV absorption data. Nitrate concentrations ranged from 0 to 9 μmol/L on very short timescales, mainly due to tidal effects. Comparison of continuous optical nitrate measurements was performed against conventional wet-chemical analyses of discrete water samples which lead to a standard deviation of 1.7 μmol/L NO₃^?. High resolution measurements performed at a tidal inlet demonstrated the capability to map nitrate dynamics in turbid coastal environments.     

Crustal and uppermost mantle S-wave velocity below the East European Craton in northern Poland from the inversion of ambient-noise records

International Journal of Earth Sciences - The P-wave velocities (Vp) within the East European Craton in Poland are well known through several seismic experiments which permitted to build a...     

Longitudinal asymmetry of craters' density distributions on the icy satellites

Crater's density distribution versus satellitographical longitude was searched for seven icy satellites: two of Jupiter (Ganymede and Callisto) and five of Saturn (Mimas, Tethys, Dione, Rhea and Iapetus). Craters were classified according to their size. Four bins of the craters' diameter were used. Density distributions were found in the longitudinal sectors of the near-equatorial stripes that circumscribe the satellites. The size distributions (R-plots) were done independently for each of the eight longitudinal sectors of the satellites. Searching for the leading/trailing (apex/antapex) and the near-side/far-side asymmetry was done. It was found that the crater density is longitudinally asymmetric for all seven satellites being studied. However, the apex–antapex asymmetry is much less pronounced than predicted by theory of Zahnle et al. (2003), for impacts on the satellites by ecliptic comets. We conclude that the impact craters observed on the considered satellites are mostly originated from planetocentric swarm of debris. In that case longitudinal asymmetry is not expected, as stated by Horedt and Neukum, 1984a, Horedt and Neukum, 1984b. However, cratering longitudinal asymmetry that we observe for Mimas perfectly agrees with calculations of Alvarellos et al. (2005). It is very likely that important part of craters on Mimas were formed due to impacts of ejecta originated from crater Herschel.     

Web-Based GIS as a Tool for Supporting Marine Research

Collecting marine data during hydroacoustic research surveys is a complex task, which not only consists of measurements but also analysis, validation, and interpretation of information acquired by various sensors. Automatic integration, visualization, and processing of collected data allow for a more precise investigation of the researched phenomena. The paper presents a dedicated Web-based system for fusion and dissemination of data from satellite imagery, hydrological measurements using CTD probes, acoustic surveys by multibeam systems, side-scan sonars and singlebeam echosounders, as well as live radar feed and oil spill spread models. The system has been designed as a tool for supporting research using the aforementioned techniques.     

Biosorption of cadmium(II), lead(II) and cobalt(II) from aqueous solution by biochar from cones of larch (<Emphasis Type="Italic">Larix decidua</Emphasis> Mill. <Emphasis Type="Italic">subsp. decidua</Emphasis>) and spruce (<Emphasis Type="Italic">Picea abies</Emphasis> L. H. Karst)

Because of their physicochemical properties, biochars can be used as sorption materials for removal of toxic substances. The purpose of the present study was to determine whether biochar obtained from cones of larch (Larix decidua Mill. subsp. decidua) and spruce (Picea abies L. H. Karst) could be used as a sorbent for Cd²⁺, Pb²⁺ and Co²⁺ in aqueous solutions. So far, this feedstock had not been tested in this respect. The material was subjected to pyrolysis at 500 and 600 °C for the duration of 5, 10 and 15 min. The obtained pyrolysates were found to differ in terms of pH and the contents of the essential macroelements. The different values of these parameters were determined for varying temperature, duration of the pyrolysis process and type of feedstock. Sorption capacities of the biochars for removal of Cd²⁺, Pb²⁺ and Co²⁺ were examined using simulated contamination of aqueous solutions with salts of these metals. The findings showed the highest, nearly complete, removal for Pb²⁺ were maximum 99.7%, and almost three times lower value for Cd²⁺ and Co²⁺ (respectively, 35.7 and 24.8%). It was demonstrated that pyrolysis of conifer cones produced optimum sorption capacities when the process was conducted at a temperature of 500 °C for the duration of 5 min. It was shown that products of spruce cone pyrolysis were characterized by better sorption capacity in comparison with products of larch cone pyrolysis. The properties of conifer cone biochar create the possibility of using it as an adsorbent in water and wastewater treatment as well as in production of filters and activated carbon.     

Identification of seismic anomalies caused by gas saturation on the basis of theoretical P and PS wavefield in the Carpathian Foredeep,SE Poland

The thin-layer build of the Carpathian Foredeep Miocene formations and large petrophysical parameter variation cause seismic images of gas-saturated zones to be ambiguous, and the location of prospection wells on the basis of anomalous seismic record is risky. A method that assists reservoir interpretation of standard recorded seismic profiles (P waves) can be a converted wave recording (PS waves). This paper presents the results of application of a multicomponent seismic survey for the reservoir interpretation over the Chałupki Dębniańskie gas deposit, carried out for the first time in Poland by Geofizyka Kraków Ltd. for the Polish Oil and Gas Company. Seismic modeling was applied as the basic research tool, using the SeisMod program based on the finite-difference solution of the acoustic wave equation and equations of motion. Seismogeological models for P waves were developed using Acoustic Logs; S-wave model (records only from part of the well) was developed on the basis of theoretical curves calculated by means of the Estymacja program calibrated with average S-velocities, calculated by correlation of recorded P and PS wavefields with 1D modeling. The conformity between theoretical and recorded wavefields makes it possible to apply the criteria established on the basis of modeling for reservoir interpretation. Direct hydrocarbon indicators (bright spots, phase change, time sag) unambiguously identify gas-prone layers within the ChD-2 prospect. A partial range of the indicators observed in the SW part of the studied profile (bright spot that covers a single, anticlinally bent seismic horizon) points to saturation of the horizon. The proposed location is confirmed by criteria determined for converted waves (continuous seismic horizons with constant, high amplitude) despite poorer agreement between theoretical and recorded wavefields.