We have conducted ultrasonic experiments, between 0.3 and 1 MHz, to measure velocity attenuation ([Formula: see text]) anisotropy of P- S-waves in dry Whitby Mudstone samples as a function stress. found the degree be large 70% for attenuation. The sensitivity P-wave change with applied stress is more conspicuous than S-waves. closure aspect-ratio pores (and/or micro cracks) seems dominant mechanism controlling anisotropy. Generally, highest perceived that their bed layering perpendicular...

This article provides the state-of-the-art on optimal planning and design of future district heating (DH) systems. The purpose is to provide practical information first-step actions for countries with a low DH market share cooling supply. Previous research showed that those countries, establishing heat atlas accurate geographical data an essential prerequisite promote development In this review, techniques building high-quality are elaborated. includes review methodologies thermal energy...

Abstract The crack initiation stress threshold ( $${\sigma }_{\mathrm{ci}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>σ</mml:mi> <mml:mi>ci</mml:mi> </mml:msub> </mml:math> ) is an essential parameter in the brittle failure process of rocks. In this paper, a volumetric strain response method (VSRM) proposed to determine based on two new concepts, i.e., dilatancy resistance state index $${\delta <mml:mi>δ</mml:mi> and maximum value difference...

Underground constructions often encounter water environments, where water–rock interaction can increase porosity, thereby weakening engineering rocks. Correspondingly, the failure criterion for chemically corroded rocks becomes essential in stability analysis and design of such structures. This study enhances applicability Hoek-Brown (H-B) structures operating corrosive conditions by introducing a kinetic porosity-dependent instantaneous mi (KPIM). A multiscale experimental investigation,...

Acoustic signals are used extensively in the oil industry to determine physical properties of reservoir rock. In interpretation these empirical laws play a major role. To obtain more fundamental recorded wavetrains, need for comprehensive theory acoustic wave propagation and damping rocks is obvious. this respect, Biot's (1956a,b) straightforward effective two‐phase theory. contrast Biot, who derived macroscopic equations saturated poro‐elastic material by postulating definite...

We study the wave properties at a fluid/porous‐medium interface by using newly derived closed‐form expressions for reflection and transmission coefficients. illustrate usefulness of these relatively simple applying them to water/porous‐medium (with open‐pore or sealed‐pore boundary conditions), where porous medium consists (1) water‐saturated clay/silt layer, (2) sand (3) an air‐filled (4) layer. observe in frequency range 5 Hz–20 kHz that fast P‐wave S‐wave velocities four materials are...

The dynamic interaction between a rigid porous structure (porosity ϕ) and its saturating fluid is studied. From the microscopic conservation laws constitutive relations, macroscopic equations are derived. An averaging technique proposed discussed by for example Lévy, Auriault Burridge &amp; Keller used, from which we reformulate theory Johnson, Koplik Dashen. then serve to describe high-frequency behaviour of an oscillating within sample. This may be characterized length parameter Λ...

The moisture-induced instability of metal halide perovskites is one the major challenges for perovskite devices. Although compositional engineering has been widely employed to improve overall stability perovskites, its effect on received little attention. Here, we systematically study interaction water with surfaces primary AMX3 (A+ = MA+, FA+, Cs+; M2+ Pb2+, Sn2+; X− I−, Br−), by using Density Functional Theory (DFT) calculations and comprehensive chemical bonding analysis. We reveal that...

Hydrogen as a clean energy source is receiving great attention, and over-ground storage using porous materials has been identified promising alternative to current solutions. The general disadvantage the relatively weak solid–gas interaction adsorption energy, providing low gravimetric volumetric capacities extreme operational conditions. Here we propose Au-doped carbon nanotubes (CNTs) an efficient for reversible hydrogen capture at high temperatures. This work investigates properties of...

Seismoelectric (SE) methods are potentially interesting for subsurface characterization by exploiting the coupling between seismic waves and electromagnetic fields in fluid-saturated porous media. While traditional SE techniques have primarily focused on body-wave-induced signals, recent research has highlighted significant advantages of surface wave-induced including enhanced amplitudes increased sensitivity to near-surface heterogeneities. These characteristics make signals particularly...

Abstract The empirical classification of gamma-ray bursts (GRBs) is based on their distribution in the plane burst duration and spectral hardness. Two distinct distributions, long-soft short-hard bursts, are observed this plane, forming basis for long short scheme. Traditionally, scheme was mapped to two different GRB progenitor classes. However, several recent have challenged mapping. This work investigates how an observer’s viewing angle relative jet axis influences duration-hardness...

Understanding the seismoelectric interface response is important for developing field methods oil exploration and environmental/engineering geophysics. The existing theory has never been validated systematically by controlled experiments. We have designed developed an experimental setup in which acoustic-to- electromagnetic wave conversions at interfaces are measured. An acoustic source emits a pressure that impinges upon porous sample. reflected electric-wave potential recorded wire...

An equilibrium based comparative study of CaCl₂ and MgCl₂ hydrates reveals that have better resistance against hydrolysis compared to hydrates; therefore it can improve the durability chloride salt hydrates.

Due to the requirement for developing more sustainable constructions, natural fibers from agricultural wastes, such as coir fibers, have been increasingly used an alternative in concrete composites. However, influence of on hydration and shrinkage cement-based materials is not clear. In addition, limited information about reinforcing mechanisms can be found. The goal this research investigate effects reaction, microstructure, shrinkages, mechanical properties light-weight aggregate (LWAC)....

The strength criterion of rock is essential for stability control and safety design geotechnical engineering constructions. Due to its widespread adoption, the Mohr–Coulomb (M-C) prominent among criteria. However, M-C constrained by three significant limitations: it fails capture nonlinear response, overlooks critical state, disregards σ2. This study introduces a novel Stress-dependent Instantaneous Friction angle Cohesion (SIFC) model represent convex envelope intact rock, covering spectrum...

The influence of a small amount gas within the saturating liquid porous medium on acoustic wave propagation is investigated. It assumed that volumes are spherical, homogeneously distributed, and they very narrow range bubble sizes. shown compressibility fluid determined by viscous, thermal, newly introduced Biot-type damping oscillating bubbles, with mean size concentration as important parameters. Using super-saturation technique, homogeneous gas–liquid mixture test column obtained. Gas...

A cube-corner angle-measuring interferometer has been developed which reproduces angles up to 30° with a precision of 0.01″. The angular dependence the interference order rigorously follows sine law and any angle in range may be measured an accuracy is limited only by error full scale calibration angle. Theory, construction details, alignment procedures are given. instrument insensitive both translation tilting axis rotation. As constructed had ±15°, suggested improvements should increase...

We designed and developed an experimental setup in which acoustic to electromagnetic (EM) wave conversions at interfaces can be measured. Theoretical results are obtained with electrokinetic full‐waveform theoretical model, where use was made of the Sommerfeld approach. Using bimodal samples, different fluid–solid interface effects saturating fluids were investigated. The contrast between water water‐saturated porous glass samples is larger than oil‐saturated samples. Fontainebleau sandstone...