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This paper describes two algorithms for generating test signals to efficiently test the linearity of ADCs. Linearity is an important testing item for ADCs, and it takes a long time (hence is costly) to test especially low-sampling-rate, high-resolution ADCs. We have proposed to generate a test signal consisting of multiple-sine waves, to precisely test the linearity for specific important codes (such as around the center of the output codes), using an arbitrary waveform generator (AWG) and an analog filter in our previous studies. Here, we formulate them for general use. Their verification is performed on a single sine wave, and good results are obtained to show the validity of the derivation algorithm.

Aqueous fluids are one of the principal agents of chemical transport in Earth´s interior. The precise determination of fluid fractions is essential to understand bulk physical properties, suc...

Fluid flow on different scales is of interest for several Earth science disciplines like petrophysics, hydrogeology and volcanology. To parameterize fluid flow in large-scale numerical simulations (e.g. groundwater and volcanic systems), flow properties on the microscale need to be considered. For this purpose experimental and numerical investigations of flow through porous media over a wide range of porosities are necessary. In the present study we sinter glass bead media with various porosities, representing shallow depth crustal sediments. The microstructure, namely effective porosity and effective specific surface, is investigated using image processing. We furthermore determine flow properties like hydraulic tortuosity and permeability using both experimental measurements and numerical simulations. By fitting microstructural and flow properties to porosity, we obtain a modified Kozeny-Carman equation for isotropic low-porosity media, that can be used to simulate permeability in large-scale numerical models. To verify the modified Kozeny-Carman equation we compare it to the numerically computed and experimentally measured permeability values.

Isothermal vapor-liquid equilibrium data of propylene oxide-ethylene and ethyl ether-ethylene systems were measured by a static method at 25°C and 40°C. The consistency of experimental results is examined by an enhancement factor of the vapor phase and by the Henry constant (f2/x2) of the liquid phase. By use of the Lewis fugacity rule for ethylene in the vapor phase, the activity coefficients of liquid phase and the fugacity coefficients of vapor phase are evaluated from themodynamic relationships. The P-x-y data of both systems are correlated with the Redlich-Kwong equation modified by Soave and the perturbation equation proposed by Gubbins and Twu. In the normal probability plot of the residuals, the SRK equation gives better correlation results for both systems.