Ion selectivity in multi-channel CDI: Permselectivity of porous carbon capacitive membrane electrodes used in multi-channel capacitive deionisation

Capacitive deionisation (CDI) is a desalination technology that removes ionic species from water through electrostatic attraction. Recently, a new CDI cell architecture has been developed with multiple channels and electrodes. Here, the ions are driven to migrate from channel to channel to desalinate the water. The inner electrodes of such a...

Impact of clay mineralogy on the petrophysical properties of tight sandstones

A full petrographic and petrophysical characterization of tight sandstones has been conducted as part of ongoing study of Carbon Dioxide Enhanced Oil and Gas Recovery (CO₂-EOR/EGR) and CO₂sequestration. The main purpose of this study is to give novel perception into the interplay of the rock characteristics and fluid...

Effects of fir-wood biochar on CH4 oxidation rates and methanotrophs in landfill cover soils packed at three different proctor compaction levels

Application of biochar to landfill cover soils can purportedly improve methane (CH4) oxidation rates, but understanding the combined effects of soil texture, compaction, and biochar on the activity and composition of the methanotrophs is limited. The amendment of wood biochar on two differently textured landfill cover soils at three compaction...

A reappraisal of the ink-bottle effect and pore structure of cementitious materials using intrusion-extrusion cyclic mercury porosimetry

Reliable characterization of the pore structure is essentially important for transport-related durability studies of cementitious materials. Mercury intrusion porosimetry has been commonly used for pore structure measurement while the ink-bottle effect significantly affects the trustworthiness of pore size features of cementitious materials....

Drying shrinkage of alkali-activated concrete -State-of-the-art: a research study into the mechanisms, the influencing factors, and mitigation strategies of drying shrinkage of alkali-activated concrete

Alkali-activated concrete (AAC) has emerged as an environmentally friendly alternative to conventional concrete, as It is a cement-free concrete made by activating precursors (mainly low-cost, low-CO2 industrial by-products) with alkalis. AAC has demonstrated some remarkable mechanical properties and long-term performance (e.g., high strength,...

Characterization and Chemical Performance Assessment of Cementitious Materials: In Relation to the Dutch Case of Geologic Disposal of Nuclear Waste

In this study, non-destructive methods are applied to quantify the influence of concrete degradation by geologic conditions on the ability to retain nuclear waste deep underground in The Netherlands. Nuclear reactors play an important role in all four scenarios of the recent report of the IPCC to reach the CO2 reduction goals. Safety related...

Effect of pore size distribution and particle size of porous metal oxides on phosphate adsorption capacity and kinetics

Phosphate is a vital nutrient but its presence in surface waters even at very low concentrations can lead to eutrophication. Adsorption is often suggested as a step for reducing phosphate down to very low concentrations. Porous metal oxides can be used as granular adsorbents that have a high surface area and hence a high adsorption capacity....

Mesoscopic modeling of the impact behavior and fragmentation of porous concrete

This study presents the numerical analyses conducted to investigate the impact behavior of different porous concretes, which have also been cast and tested experimentally. For a realistic representation of the real porous concretes containing arbitrary shaped air pores, a mesh generation code was developed in which the aggregates in the...

Ink-bottle effect and pore size distribution of cementitious materials identified by pressurization-depressurization cycling mercury intrusion porosimetry

Capturing the long-term performance of concrete must be underpinned by a detailed understanding of the pore structure. Mercury intrusion porosimetry (MIP) is a widely used technique for pore structure characterization. However, it has been proven inappropriate to measure the pore size distribution of cementitious materials due to the ink-bottle...

Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

Experiments have been carried out to study the influence of moisture condition, including moisture content and its distribution, on the chloride diffusion in partially saturated ordinary Portland cement mortar. The mortar samples with water-to-cement (w/c) ratios of 0.4, 0.5 and 0.6, cured for 1 year, were preconditioned to uniform water...

Expansion and degradation of cement paste in sodium sulfate solutions

External sulfate attack is a progressive degradation process that may cause expansion, cracking, loss of binder cohesion and increased permeability in cementitious materials. Crystallization pressure theory has often been referred to as the most likely mechanism. However, thus far the stress causing the expansion has not been quantified. In...

Characterization and comparison of capillary pore structures of digital cement pastes

More and more studies are based on digital microstructures of cement pastes obtained either by numerical modelling or by experiments. A comprehensive understanding of the their pore structures, therefore, becomes significant. In this study, the pore structure of a virtual cement paste (HYMO-1d) generated by cement hydration model HYMOSTRUC 3D...

Particulate structure and microstructure evolution of concrete investigated by DEM: Part 2: Porosimetry in hydrating binders

Durability of concrete in engineering structures is becoming more and more of a major problem. Research into such problems is complicated and expensive, however. Developments in computer technology make it possible nowadays realistically simulating cementitious materials and studying its pore network structure. In this paper use is made of the...

Discrete element modeling approach to porosimetry for durability risk estimation of concrete

The paper introduces a novel approach to porosimetry in virtual concrete, denoted as random node structuring (RNS). The fresh state of this particulate material is produced by the DEM system HADES. Hydration simulation is a hybrid approach making use of wellknown discretization and vector methods. Particle interferences (overlap) in the dynamic...

Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

Purpose This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. Methods The method applies the MATLAB image processing toolbox to images of coated particles taken with Confocal Laser Scanning...