Fate of Benzalkonium Chloride in a Sewage Sludge Low Temperature Conversion Process Investigated by LC‐LC/ESI‐MS/MS

Thermocatalytic low temperature conversion (LTC) is a new method for the disposal of sewage sludge. Using this method, sludge is converted into a residual solid (coal) along with reaction water, oil, and non‐condensable gases. The oil can be used as an energy source and the coal as a substitute for charcoal. To this end, it is important to determine whether there are any easily available contaminants present in the coal generated by the process. Contaminants that can be strongly sorbed by sewage sludge solids are, e. g., pharmaceuticals and disinfectants. As an example the fate of the persistent and strong adsorbing disinfectant benzalkonium chloride (BAC) has been investigated within the LTC process. The sewage sludge was spiked with BAC and then subjected to the LTC process. The resulting coal was extracted and analyzed using LC‐LC/ESI‐MS/MS (ion trap). BAC could not be detected in the LTC coal, although it could be extracted from the spiked sludge before the LTC treatment. It can thus be concluded that the investigated compound is not easily available in the coal, and hence that its use does not present a risk.     

3D mapping as a tool for the planning of preservation measures on sculptures made of natural stone

The article deals with the comparison between 2D and 3D evaluation of surface areas of sculptures. The objects chosen for investigation were Apollo (Carrara Marble, Potsdam Sanssouci), Flora (Laas Marble, Castle and Park Nymphenburg Munich) and Juno (Cotta Sandstone, Baroque Garden Großsedlitz/Dresden). Photographs showing the sculptures from all sides were used for calculating 2D surface areas with AutoCAD 2018 software. 3D models were generated with T-Scan 2 (Steinbichler Company), and 3D surface areas were evaluated with CAD software Geomagic Studio. The results show that 3D total surface area determinations of virtual 3D models are much more precise than 2D determinations on photographs. The values of the total surface area differ significantly. In case of Apollo 2D measurement captures only 66% of the real total surface. For measuring surface roughness, standardized Bosch sandpapers with P classification were used. Microphotographs of marble and sandstone surfaces show the development and the general optical appearance of increasing roughness. As expected, 2D calculation gives smaller values than 3D calculation also in case of surface roughness. In case of Apollo the P400 roughness area calculated with 2D measurement yields only 26% of the real area calculated with 3D. The accuracy of the surface 2D measurement clearly depends on the complexity of the sculpture because undercuts cannot be captured on photographs. It is shown that accurate information about the distribution of damage phenomena helps to improve planning conservation measures.     

Multiscale formulation for coupled flow-heat equations arising from single-phase flow in fractured geothermal reservoirs

Efficient heat exploitation strategies from geothermal systems demand for accurate and efficient simulation of coupled flow-heat equations on large-scale heterogeneous fractured formations. While the accuracy depends on honouring high-resolution discrete fractures and rock heterogeneities, specially avoiding excessive upscaled quantities, the efficiency can be maintained if scalable model-reduction computational frameworks are developed. Addressing both aspects, this work presents a multiscale formulation for geothermal reservoirs. To this end, the nonlinear time-dependent (transient) multiscale coarse-scale system is obtained, for both pressure and temperature unknowns, based on elliptic locally solved basis functions. These basis functions account for fine-scale heterogeneity and discrete fractures, leading to accurate and efficient simulation strategies. The flow-heat coupling is treated in a sequential implicit loop, where in each stage, the multiscale stage is complemented by an ILU(0) smoother stage to guarantee convergence to any desired accuracy. Numerical results are presented in 2D to systematically analyze the multiscale approximate solutions compared with the fine scale ones for many challenging cases, including the outcrop-based geological fractured field. These results show that the developed multiscale formulation casts a promising framework for the real-field enhanced geothermal formations.     

On multicomponent gas diffusion and coupling concepts for porous media and free flow: a benchmark study

Computational Geosciences - Multicomponent gas transport in porous media and at the interface between porous media and free flow occurs in a wide range of technical and environmental systems....     

Mining Trajectory Data and Geotagged Data in Social Media for Road Map Inference

As mapping is costly and labor‐intensive work, government mapping agencies are less and less willing to absorb these costs. In order to reduce the updating cycle and cost, researchers have started to use user generated content (UGC) for updating road maps; however, the existing methods either rely heavily on manual labor or cannot extract enough information for road maps. In view of the above problems, this article proposes a UGC‐based automatic road map inference method. In this method, data mining techniques and natural language processing tools are applied to trajectory data and geotagged data in social media to extract not only spatial information – the location of the road network – but also attribute information – road class and road name – in an effort to create a complete road map. A case study using floating car data, collected by the National Commercial Vehicle Monitoring Platform of China, and geotagged text data from Flickr and Google Maps/Earth, validates the effectiveness of this method in inferring road maps.     

Intragranular deformation mechanisms in calcite deformed by high-pressure torsion at room temperature

Mineralogy and Petrology - Polycrystalline calcite was deformed to high strain at room-temperature and confining pressures of 1–4 GPa using high-pressure torsion. The high confining...     

A hydrographic time series station in the Wadden Sea (southern North Sea)

In the tidal inlet between the East Frisian islands of Langeoog and Spiekeroog, southern North Sea, a time-series station was set up in autumn 2002 as part of the research programme BioGeoChemistry of Tidal Flats run by the University of Oldenburg. The purpose of the station is to provide continuous data on physical, biological and chemical parameters. In addition to instruments recording basic hydrographic and meteorological parameters, the time-series station is equipped with acoustic Doppler profilers for measuring surface waves and current profiles. Compact optical spectrometers are being used for spectral measurements of seawater transmission and for daylight reflectance. Additional sensors were installed for measuring oxygen, nutrients and methane in the seawater. The data shall help to quantify the flux of dissolved and suspended matter between the backbarrier tidal flat and the open sea and to characterise the material transformation in the tidal flat area by biogeochemical processes over the tidal cycle. Due to its novel design, operation of the station is also possible during winter and under extreme weather conditions (gales, storm surges, and sea ice) when data sampling with conventional platforms such as research vessels, buoys, or smaller poles could not be performed in the past. In this way, time series of data are obtained, which include events that are most relevant to the evolution of this coastal area. The performance of the station and its equipment are presented with data covering 6 years of operation. Time series of air and water temperature as well as seawater salinity demonstrate the multiyear dynamics of these parameters in the East Frisian Wadden Sea. Hydrographic data collected under specific meteorological conditions such as gales and storm surges exemplify the all-weather capabilities of the station and its value for studying hydrographic processes in the Wadden Sea.     

Distributions and characteristics of dissolved organic matter in temperate coastal waters (Southern North Sea)

The spatial and temporal distributions of chromophoric dissolved organic matter (CDOM) and dissolved organic carbon (DOC) was studied in the East-Frisian Wadden Sea (Southern North Sea) during several cruises between 2002 and 2005. The spatial distribution of CDOM in the German Bight shows a strong gradient towards the coast. Tidal and seasonal variations of dissolved organic matter (DOM) identify freshwater discharge via flood-gates at the coastline and pore water efflux from tidal flat sediments as the most important CDOM sources within the backbarrier area of the Island of Spiekeroog. However, the amount and pattern of CDOM and DOC is strongly affected by various parameters, e.g. changes in the amount of terrestrial run-off, precipitation, evaporation, biological activity and photooxidation. A decoupling of CDOM and DOC, especially during periods of pronounced biological activity (algae blooms and microbial activity), is observed in spring and especially in summer. Mixing of the endmembers freshwater, pore water, and open sea water results in the formation of a coastal transition zone. Whilst an almost conservative behaviour during mixing is observed in winter, summer data point towards non-conservative mixing.     

Atom probe tomography of space‐weathered lunar ilmenite grain surfaces

The surfaces of airless bodies, such as the Moon and asteroids, are subject to space weathering, which alters the mineralogy of the upper tens of nanometers of grain surfaces. Atom probe tomography (APT) has the appropriate 3‐D spatial resolution and analytical sensitivity to investigate such features at the nanometer scale. Here, we demonstrate that APT can be successfully used to characterize the composition and texture of space weathering products in ilmenite from Apollo 17 sample 71501 at near‐atomic resolution. Two of the studied nanotips sampled the top surface of the space‐weathered grain, while another nanotip sampled the ilmenite at about 50 nm below the surface. These nanotips contain small nanophase Fe particles (~3 to 10 nm diameter), with these particles becoming less frequent with depth. One of the nanotips contains a sequence of space weathering products, compositional zoning, and a void space (~15 nm in diameter) which we interpret as a vesicle generated by solar wind irradiation. No noble gases were detected in this vesicle, although there is evidence for ⁴He elsewhere in the nanotip. This lunar soil grain exhibits the same space weathering features that have been well documented in transmission electron microscope studies of lunar and Itokawa asteroidal regolith grains.