Heat Transport in Unsaturated Zone Thermal Energy Storage – Analysis with Two-Phase and Single-Phase Models

We analyze a field experiment where ambient air is injected into the soil during the summer and extracted again during the winter. A multiphase model accounting for the conductive transport as well as the convective transport with the moving liquid and gas phases is used along with a more simplified single-phase model where the convective transport is due to the gas alone. The latter model also accounts for subzero wintertime temperatures. The multiphase model captures well both the seasonal variations and the actual test sequence, the main calibration being in the adjustment of medium permeabilities based on the observed pressure responses. The effect of the injection pump on the temperature and humidity of the injection air needs to be known accurately. Taking into account the humidity of the injection air explicitly instead of using humidity-corrected enthalpy values also has an effect. The effect of various humidity and specific enthalpy assumptions is of the order of 1–1.5°C, while ignoring the wintertime subzero temperatures has an effect of 1–2°C. These differences are of the same order of magnitude as the heterogeneity-introduced differences in field data. Using the simplified single-phase model typically appears to cause a difference of 1–2°C, but can yield an even higher deviation of the order of 3–4°C.     

Waveform control of orientation-dependent ionization of DCl in few-cycle laser fields

Strong few-cycle light fields with stable electric field waveforms allow controlling electrons on time scales down to the attosecond domain. We have studied the dissociative ionization of randomly oriented DCl in 5 fs light fields at 720 nm in the tunneling regime. Momentum distributions of D(+) and Cl(+) fragments were recorded via velocity-map imaging. A waveform-dependent anti-correlated directional emission of D(+) and Cl(+) fragments is observed. Comparison of our results with calculations indicates that tailoring of the light field via the carrier envelope phase permits the control over the orientation of DCl(+) and in turn the directional emission of charged fragments upon the breakup of the molecular ion.     

Untersuchung von Mehl

Ohne Zusammenfassung     

Schwefelbestimmung in Stahl und Eisen

Ohne Zusammenfassung     

Wasserzusatz

Ohne Zusammenfassung     

Die Trennung des Zinns von anderen Metallen, insbesondere die Bestimmung desselben durch F?llung Mit Cupferron

Ohne Zusammenfassung     

Multi-element determination with solid sampling by laser ablation using electrothermal atomisation and continuum source coherent forward scattering spectrometry

Laser ablation allows fast and easy sampling of solids with a spatial resolution of some (μm vertical and some 30 μm lateral. The deposition of the laser generated aerosol in a graphite furnace in combination with continuum source CFS allows simultaneous multi-element analysis and the use of internal standards. The aerosol is transported into the graphite furnace with the inert gas flow and deposited by means of a corona discharge inside the tube. The deposition efficiency shows an enhancement by about three orders of magnitude, compared to the deposition without a field. The analytical precision and accuracy has been tested with metals and mineral samples as glassy cinder from a waste incineration plant.