Impacts of anisotropy coefficient and porosity on the thermal conductivity and P-wave velocity of calcarenites used as building materials of historical monuments in Morocco

It is essential to study the porosity,thermal conductivity,and P-wave velocity of calcarenites,as well as the anisotropy coefficients of the thermal conductivity and P-wave velocity,for civil engineering,and conservation and restoration of historical monuments.This study focuses on measuring the thermal conductivity using the thermal conductivity scanning(TCS)technique and measuring the P-wave ve-locity using portable equipment.This was applied for some dry and saturated calcarenite samples in the horizontal and vertical directions(parallel and perpendicular to the bedding plane,respectively).The calcarenites were selected from some historical monuments in Morocco.These physical properties were measured in the laboratory to find a reliable relationship between all of these properties.As a result of the statistical analysis of the obtained data,excellent linear relationships were observed between the porosity and both the thermal conductivity and porosity.These relationships are characterized by relatively high coefficients of determination for the horizontal and vertical samples.Based on the thermal conductivity and P-wave velocity values in these two directions,the anisotropy coefficients of these two properties were calculated.The internal structure and the pore fabric of the calcarenite samples were delineated using scanning electron microscopy(SEM),while their chemical and mineral compositions were studied using the energy dispersive X-ray analysis(EDXA)and X-ray diffraction(XRD)techniques.

Influence of anisotropy on the electrical conductivity and diffusion coefficient of dry K-feldspar： Implications of the mechanism of conduction

The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa in a frequency range of 10-1 Hz–106 Hz. The measured electrical conductivity along the ⊥ [001] axis direction decreases with increasing pressure, and the activation energy and activation volume of charge carriers are determined to be 1.04 ± 0.06 e V and 2.51 ± 0.19 cm~3/mole, respectively. The electrical conductivity of K-feldspar is highly anisotropic, and its value along the⊥ [001] axis is approximately three times higher than that along the ⊥ [100] axis. At 2.0 GPa, the diffusion coefficient of ionic potassium is obtained from the electrical conductivity data using the Nernst–Einstein equation. The measured electrical conductivity and calculated diffusion coefficient of potassium suggest that the main conduction mechanism is of ionic conduction, therefore the dominant charge carrier is transferred between normal lattice potassium positions and adjacent interstitial sites along the thermally activated electric field.

Estimating aquifer transmissivity using Dar-Zarrouk parameters to delineate groundwater potential zones in Alluri Seetharama Raju District,Andhra Pradesh, India

This study aimed to explore groundwater potential zones in the EGMB of Alluri Seetharama Raju district, Andhra Pradesh, India, for drinking and agriculture purposes. To achieve this goal, 72 Vertical Electrical Soundings(VES) were conducted using the Schlumberger electrode configuration. The resistivity sounding data were analyzed to determine the aquifer thickness, basement depth, Dar-Zarrouk parameters,and aquifer transmissivity. Spatial distribution maps were generated for these parameters to understand the subsurface formation. The analysis revealed a linear groundwater potential zone(8.46 km~2) in the eastern part of the study area, extending in the NNE-SSW direction for 9.6 km. Six VES locations(P24, P27, P29,P30, P33, and P38) in this zone exhibit good potential(>30 m aquifer thickness), while the three VES locations(OP19, P5, and P46) in the central region are recommended for drilling bore wells. Additionally,moderate aquifer thickness(20–30 m) are identified in other VES locations(OP14, OP20, P4, P10, P12,P13, P15, P17, P18, P31, P46, and P50) along streams in the western and central part of the area, which can yield reasonable quantities of water. This information is useful for groundwater exploration and watershed management to meet the demands of tribal population in the study area.

Molecular dynamics study of anisotropic growth of silicon

Based on the Tersoff potential, molecular dynamics simulations have been performed to investigate the kinetic coefficients and growth velocities of Si（100）,（110）,（111）, and（112） planes. The sequences of the kinetic coefficients and growth velocities are μ（（100））〉 μ（（110））〉 μ（（112））〉 μ（（111））and v（（100））〉 v（（110））〉 v（（112））〉 v（（111））, respectively, which are not consistent with the sequences of the interface energies, interplanar spacings, and melting points of the four planes. However,they agree well with the sequences of the distributions and diffusion coefficients of the melting atoms near the solid–liquid interfaces. It indicates that the atomic distributions and diffusion coefficients affected by the crystal orientations determine the anisotropic growth of silicon. The formation of stacking fault structure will further decrease the growth velocity of the Si（111） plane.