Capillary Uptake Research Articles

Magnetite-latex nanoparticle motion during capillary uptake in thin, porous layers studied with UFI‐NMR

The transport of nanoparticles in porous media has received growing attention in the last decades due to environmental concerns in, for example, the printing industry, filtration, and transport of pollutants. Experimental studies on the imbibition of particle dispersions in porous media with sufficiently high spatial and temporal resolution are still challenging. This study shows how Ultra-Fast Imaging (UFI) NMR is an ideal tool for studying Fe3O4-latex particles penetration with a temporal resolution of 15 ms and spatial resolution of 18 µm. In the first part, it is shown that a calibration curve between the UFI‐NMR signal intensity and the particle concentration exists. In the second part, UFI‐NMR is used to study the penetration of a particles inside a thin nylon membrane during capillary uptake, which revealed liquid-particle front splitting and an inhomogeneous buildup of the particle concentration. Both the liquid-particle front splitting and inhomogeneous build up could be verified by Scanning Electron Microscopy. Our method allows to determine particle concentration profiles during capillary uptake within thin, porous media. Therefore, the technique can be easily extended to study particle penetrations in a wide variety of systems such thin interfaces, biomaterials, films, and filter media.

Modelling Rain Water Ingress in Hygrothermal Simulations

The hygrothermal response of building envelope components is often studied by means of numerical Heat-Air-Moisture (HAM) simulation models. There models aim to capture the most important physics that affect the transport and storage of heat and moisture due to climatic excitations. For a lot of climates and components the wind driven rain load is the main driver for moisture uptake in the construction, and as well, the trigger of important degradation phenomena e.g., freeze-thaw damage, mold growth, wood decay, corrosion, salt transport, algae growth. When building components are subjected to wind driven rain loads and driving rain wind pressures, capillary uptake in porous materials is typically considered in models, but rain water often infiltrates directly into different layers of the construction and these infiltrations may have a significant impact on the hygrothermal behavior. This paper offers a straightforward methodology to take the rain water management of building envelope components into account in hygrothermal simulations. For different types of façade systems a categorical approach is presented to simulate rain water ingress into the different layers. Next to that, also the drainage and retention is discussed in detail. Finally, this methodological approach is embedded in the SAMiRA-framework, which comprises 3 performance levels for each input parameter of the simulations: (i) Superior, (ii) Advanced, (iii) Minimum Requirement Approach. Hence, 3 different levels are offered to implement rainwater infiltration in hygrothermal simulations.

Liquid uptake in porous cellulose sheets studied with UFI-NMR: Penetration, swelling and air displacement

Liquid penetration in porous cellulosic materials is crucial in many technological fields. The complex geometry, small pore size, and often fast timescale of liquid uptake makes the process hard to capture. Effects such as swelling, vapor transport, film flow and water transport within cellulosic material makes transport deviate from well-known relations such as Lucas-Washburn and Darcy's Law. In this work it is demonstrated how Ultra-Fast Imaging NMR can be used to simultaneously monitor the liquid distribution and swelling during capillary uptake of water with a temporal- and spatial resolution of 10 ms and 14.5–18 μm respectively. The measurements show that in a cellulose fiber sheet, within the first 65 ms, liquid first penetrates the whole sheet before swelling takes place for another 30 s. Furthermore, it was observed that the liquid front traps 15 v% of air which is slowly replaced by water during the final stage of liquid uptake. Our method makes it possible to simultaneously quantify the concentration of all three phases (solid, liquid and air) within porous materials during processes exceeding 50 ms (5 times the temporal resolution). We hence believe that the proposed method should also be useful to study liquid penetration, or water diffusion, into other porous cellulosic materials like foams, membranes, nonwovens, textiles and films.

Application of automatic image analysis to evaluate the anisotropy of autoclaved aerated concrete for moisture transport

Autoclaved aerated concrete (AAC) is an artificial building material commonly applied in energy efficient buildings. Blocks of AAC are characterized by relatively homogenous distribution of pores and their dimensions. However, during manufacturing there occurs irregular pores positioning which may influence water transport processes. This phenomenon is called anisotropy which could be evaluated using standard gravimetric or electric methods of moisture detection. In this article we propose a method of level of anisotropy evaluation using image analysis. During the research a set of AAC samples was prepared and examined using time domain reflectometry (TDR) method for capillary uptake phenomenon and in parallel the cross-sections visual analyses were conducted. Both techniques confirmed the anisotropic features of the tested material.

Parameters of Concrete Modified with Micronized Chalcedonite.

The PN-EN 197-1:2012 standard allows the use of additives as the main component above 5.0% by mass, as well as as a secondary component in an amount less than 5.0% by mass of cement. Proper selection of additives positively affects the rheological characteristics and hardened concrete parameters during longer maturity periods. Additives have already become an integral component of concrete mixes. The aim of the research is to confirm the possibility of using the tested additive in the composition of concrete mixes in an amount of 15% relative to the amount of cement, which would solve the problem of storing and utilizing waste generated during the production of broken chalcedonite aggregates. The planned laboratory tests were carried out for concrete of three classes, C30/37, C35/45, C40/50, according to the PN-EN 206+A1:2016-2 standard, with the addition of chalcedonite dust in a constant amount of 15% relative to cement, and three series without additives as control series. The additive used for concrete mixes was chalcedonite dust with a diameter below 72 μm. It is waste from a broken aggregate mine. The research program included rheological tests of fresh concrete mix, i.e., air content, consistency, bulk density, as well as parameters of hardened concrete mix-compressive strength, absorbability, and capillary uptake. Compressive strength was tested after 7, 14, 28, 56, and 90 days. The laboratory tests aimed to verify whether the addition of 15% chalcedonite dust additive would not worsen the predicted hardened concrete parameters resulting from the designed concrete classes. All three tested series, C30/37, C35/45, and C40/50, with the addition of 15% chalcedonite dust relative to the amount of cement, achieved the assumed strength classes after 28 days of maturation. Concrete mix components were correctly designed. The addition of chalcedonite dust to the concrete mix did not cause a decrease in compressive strength to the extent that the analyzed series did not meet the normative requirements for concrete classes according to the PN-EN 206+A1:2014 standard. The results of absorbability testing indicate water absorption below 5%, while the increase in sample mass in the capillary uptake test gained similar values.

Hygro-thermal characterization of the hemp concrete modified with the gum Arabic admixture

This paper presents the investigation of the hygro-thermal properties of hemp concrete modified with gum Arabic (GA) admixture. The effects of modifying agents on the composite: density, total porosity, thermal conductivity, vapor permeability, sorption/desorption curves, and capillary uptake were studied. The main findings were the following. A slight tendency to increase density (i.e., from 444.2 to 450.2 kg/m3) and decrease porosity (i.e., from 79.5 to 79.0 %) with an increase in the admixture content was observed. The exception was the composite with the lowest amount of GA admixture (i.e., 1 % wt.), which had a lower density (i.e., 440.5 kg/m3) and higher porosity (i.e., 79.8 %) than the reference composite with no admixture. Thermal conductivity for dry composites rose by approximately 10 % for higher amounts of GA admixture (i.e., to 0.1179 and 0.1181 W/m/K for 3 and 5 % wt. of GA, respectively), while for lower ones (i.e., 1 % wt.), it was comparable to reference hempcrete (0.1067 W/m/K for reference vs 0.1053 W/m/K for 1 % wt. of GA). An increase in the moisture content of composites increased thermal conductivity but also reduced its variation for different GA contents. All composites had similar water vapor permeabilities on the levels of 3∙10-11 and 5∙10-11 kg/m/s/Pa for dry and wet caps, respectively, and no simple relationship was found between water vapor permeability and GA content. The addition of GA caused the shift of sorption/desorption curves in the direction of higher moisture contents, increasing amounts of absorbed water more than two times in higher relative humidities. The presence of higher amounts of GA (i.e., 3 and 5 % wt.) reduced the height of the water rise by capillaries, i.e., by 10.3 and 21.0 %, respectively, after 8 days of testing, and slowed down the progress of capillary uptake. However, the composite with 1 % wt. GA absorbed 16.7 % more water than the reference sample.

A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete—Particular consideration of 12% chromium steel

AbstractThe critical chloride content Ccrit is an indicator of the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content Ccrit of mild and alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests employing more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, against the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing.

Moisture transport and steel rebar corrosion in repair composites incorporating Nano-Fibrillated Cellulose (NFC)

Repair of deteriorating concrete infrastructure remains a major challenge. The concern is that current repair materials are not able to prevent premature failure after a repair has been performed. Thus, an engineered repair mortar that can enhance the durability of repaired composites by mitigating moisture transport and its debilitating influence on deterioration mechanisms such as steel rebar corrosion would be highly coveted. In this study, the influence of reinforcing a repair mortar with 0.1% by volume of Nano-Fibrillated Cellulose (NFC) on the capillary water transport in monolithic and composite specimens was investigated. Micro Computed Tomography (CT) imaging was also utilized in evaluating the microstructure of sorptivity test specimens. Thereafter, the influence of repair mortars on the corrosion behavior of deformed steel rebar was investigated via natural and accelerated tests. In these tests, concrete substrates had an embedded rebar in it, and repair mortars were applied on the top creating a composite specimen with a repair interface. Some of the parameters measured were surface resistivity, half-cell potential, overlay delamination time, residual rebar pullout load and rebar corrosion degree.Sorptivity tests indicated that the NFC is indeed capable of refining the pore structure through internal curing and thus reducing the capillary uptake of water. Moreover, the tendency of the NFC to entrap micro voids, especially near the repair interface, thereby indirectly reducing moisture transport and saturation of composite specimens was confirmed by CT imaging. Natural and accelerated corrosion test results demonstrated that NFC addition inhibited rebar corrosion as indicated by reduced rebar corrosion degree and delayed delamination of the repair overlay. The NFC also provided superior surface resistivity and a higher rebar pullout load capacity after corrosion.

Influence of the Direction of Mixture Compaction on the Selected Properties of a Hemp-Lime Composite.

The aim of the research presented in the article was to check the differences in the hygro-thermal and mechanical properties of hemp-lime composites with different shives fractions, depending on the direction of mixture compaction. The research part of the paper presents the preparation method and investigation on the composites. Thermal conductivity, capillary uptake, as well as flexural and compressive strengths were examined. Additionally, an analysis of the temperature distribution in the external wall insulated with the tested composites was performed. The results confirm that the direction of compaction influences the individual properties of the composites in a similar way, depending on the size of the shives. The differences are more pronounced in the case of the composite containing longer fractions of shives. Both thermal conductivity of the material and the capillary uptake ability are lower in the parallel direction of the compaction process. Composites exhibit greater stiffness, but they fail faster with increasing loads when loaded in the direction perpendicular to compaction.

A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete: Particular consideration of 12% chromium steel

AbstractThe critical chloride content Ccrit is an indicator for the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content Ccrit of mild and an alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests using more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, with the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing.

Physical and Mechanical Properties of Sustainable Hydraulic Mortar Based on Marble Slurry with Waste Glass

This paper aims to propose and characterize a sustainable hydraulic mortar entirely obtained by the reuse of waste materials, with marble slurry coming from quarries in the north-western Sicily and glass powder coming from a waste collection plant in Marsala (Province of Trapani). The first was used as raw material to produce the mortar binder by a kilning and slaking process, while the second was used as a pozzolanic additive. The chemical and morphological characterization of the marble slurry was done by XRD, FTIR, STA and SEM analyses. Glass powder was analyzed through particle size distribution measurements, XRD and standard pozzolanic tests. Hydraulic mortars constituted by slaked lime from kilned marble slurry and waste glass powder (LGS) were prepared beside commercial Natural Hydraulic Lime (NHL) based mortars (NGS) and air-hardening lime (LSS)-based mortars. Mechanical and absorption properties of the mortars were investigated as a function of the grain size of the glass powder by means of three-point bending and compressive strength tests, capillary uptake, helium pycnometry and simultaneous thermal analysis. The results demonstrated that the formulation LGS exhibits significantly improved mechanical and absorption properties compared to air-hardening mortars (LSS). It confirms the possibility of producing a more sustainable hydraulic mortar exclusively from waste materials for civil engineering.

Effects of sludge properties in a combined process of mesophilic anaerobic-aerobic digestion

The combined medium-temperature anaerobic digestion and medium-temperature aerobic digestion (MAND/MAD) is a strategy that is suitable for the disposal of conventional activated sludge. The MAND/MAD sludge stabilization process was performed at three retention times (17, 24, and 38 days) of anaerobic digestion (AND-time) with further duration up to 22 days of the MAD process. The retention time of the MAND process had an important role in sludge stabilization. Its extension enhanced sludge stability in the aerobic digestion stage. During a MAD process, values of volatile/total solids ratio (VS/TS) presented the lowering course for the three investigated retention AND-times. The relatively long retention time of MAND leads to a higher level of soluble organic compounds (SCOD) and extracellular polymers (EPS) in the supernatant. Due to the shorter capillary uptake time at the end of digestion in the MAND/MAD system, the sludge with an AND-time of 38 days was extremely susceptible to dewatering compared to the sludge with an AND-time of 17 and 24 days.

Glow-in-the-Dark Patterned PET Nonwoven Using Air-Atmospheric Plasma Treatment and Vitamin B2-Derivative (FMN)

Flavin mononucleotide (FMN) derived from Vitamin B2, a bio-based fluorescent water-soluble molecule with visible yellow-green fluorescence, has been used in the scope of producing photoluminescent and glow-in-the-dark patterned polyester (PET) nonwoven panels. Since the FMN molecule cannot diffuse inside the PET fiber, screen printing, coating, and padding methods were used in an attempt to immobilize FMN molecules at the PET fiber surface of a nonwoven, using various biopolymers such as gelatin and sodium alginate as well as a water-based commercial polyacrylate. In parallel, air atmospheric plasma activation of PET nonwoven was carried for improved spreading and adhesion of FMN bearing biopolymer/polymer mixture. Effectively, the plasma treatment yielded a more hydrophilic PET nonwoven, reduction in wettability, and surface roughness of the plasma treated fiber with reduced water contact angle and increased capillary uptake were observed. The standard techniques of morphological properties were explored by a scanning electron microscope (SEM) and atomic force microscopy (AFM). Films combining each biopolymer and FMN were formed on PS (polystyrene) Petri-dishes. However, only the gelatin and polyacrylate allowed the yellow-green fluorescence of FMN molecule to be maintained on the film and PET fabric (seen under ultraviolet (UV) light). No yellow-green fluorescence of FMN was observed with sodium alginate. Thus, when the plasma-activated PET was coated with the gelatin mixture or polyacrylate bearing FMN, the intense photoluminescent yellow-green glowing polyester nonwoven panel was obtained in the presence of UV light (370 nm). Screen printing of FMN using a gelatin mixture was possible. The biopolymer exhibited appropriate viscosity and rheological behavior, thus creating a glow-in-the-dark pattern on the polyester nonwoven, with the possibility of one expression in daylight and another in darkness (in presence of UV light). A bio-based natural product such as FMN is potentially an interesting photoluminescent molecule with which textile surface pattern designers may create light-emitting textiles and interesting aesthetic expressions.

Influence of Hemp Shives Size on Hygro-Thermal and Mechanical Properties of a Hemp-Lime Composite.

Different fractions of hemp shives are used in the mixtures of the hemp–lime composite. The market offers shives of different granulation. It depends on the type of industrial hemp and on the capabilities of decortication machines. The aim of the research presented in the article is to check differences in the mechanical and hygro-thermal properties of composites with different shives fractions. The research part of the paper presents the preparation method and investigation on hemp–lime composites. Apparent density, total porosity, thermal conductivity, capillary uptake, vapor permeability, specific heat, mass absorptivity, flexural and compressive strength were examined. The results confirm that the shives fraction influences the individual properties of the composites. Hemp–lime composites with fine shives are characterized by higher water absorption, thermal conductivity, mechanical strength, vapor permeability as well as lower capillary-lifting capacity and specific heat than composites with thick shives.

Surface hydrophobisation of mortars with waste aggregate by nanopolymer trietoxi-isobutyl-silane and methyl silicon resin

The paper explores the possibility of applying the nanopolymer trietoxiisobutylsilane and methyl silicon resin for hydrophobisation of mortars with the lightweight aggregate addition (PVC + PUR + WD). The investigation involved the mortars with two types of hydrophobic agents, without and with waste addition (5; 10; 15%). The results and discussion referring to their micro-structure together with the interfacial transition zone (ITZ). Physical and mechanical properties, frost resistance, water absorption, as well as vapor permeability were investigated. The influence of hydrophobisation on the SFE value, CA and microroughness characteristic was also determined. The surface hydrophobisation of mortars using the A1 preparation reduced the water absorption and vapour permeability by 94.6%. The A1 agent reduced the weight loss after the F-T test by 88.9%. Surface hydrophobisation increased the CA value, and reduced the SFE value for the L5 and L10 mortars by over 3 times. The greatest effect on the decrease of A2 preparation roughness was proven. The efficiency of both agents was confirmed by the capillary uptake test conducted using the TDR equipment.

Predicting monoclonal antibody pharmacokinetics following subcutaneous administration via whole-body physiologically-based modeling.

Use of the subcutaneous (SC) route for administering monoclonal antibodies (mAbs) to treat chronic conditions has been hindered because of an incomplete understanding of fundamental mechanisms controlling mAb absorption from the SC site, and due to the limited translatability of preclinical studies. In this paper, we report on the development and evaluation of a whole-body physiologically-based model to predict mAb pharmacokinetics following SC administration. The circulatory model is based on the physiological processes governing mAb transport and includes two mAb-specific parameters representing differences in pinocytosis rate and the diffusive/convective transport rates among mAbs. At the SC administration site, two additional parameters are used to represent mAb differences in lymphatic capillary uptake and in pre-systemic clearance. Model development employed clinical intravenous (IV) plasma PK data from 20 mAbs and SC plasma PK data from 12 of these mAbs, as obtained from the literature. The resulting model reliably described both the IV and SC measured plasma concentration data. In addition, a metric based on the positive charge across the mAb's complementarity determining region vicinity was found to positively correlate with the model-based estimates of the mAb-specific parameter governing organ/tissue pinocytosis transport and with estimates of the mAb's SC lymphatic capillary clearance. These two relationships were incorporated into the model and accurately predicted the SC PK profiles of three out of four separate mAbs not included in model development. The whole-body physiologically-based model reported herein, provides a platform to characterize and predict the plasma disposition of monoclonal antibodies following SC administration in humans.

Toward Bioluminescent Materials by Plasma Treatment of Microfibrous Nonwovens, Followed by Immobilization of One or Both Enzyme(s) (Luciferase and FMN Reductase) Involved in Luminescent Bacteria.

Bioluminescent living organisms emit light through a specific biocatalyzed reaction involving a luciferin substrate and a luciferase enzyme. The present work investigated the possibility of creating optimal luminescence by immobilization of one or both the enzymes Luciferase (Luc) and FMN reductase (Red) involved in a bioluminescent bacterial system onto a plasma-activated microfibrous PET nonwoven. Parameters affecting the catalytic activity and efficiency of the bacterial system in aqueous medium were determined by luminescence intensity measurements using a luminometer. Two types of plasma, air atmospheric plasma (ATMP) and cold remote plasma (CRPNO) treatment, were used to activate the PET nonwoven. Further, one or both enzyme(s) were immobilized using a physical adsorption technique, without or with the use of natural biopolymers (gelatin and starch) and bovine serum albumin-BSA protein, to improve enzyme stability and activity. Coimmobilization of both Red and Luc enzymes on the CRPNO plasma-activated nonwoven in the presence of BSA led to the maximum luminescence. As high as 60,000 RLU equivalent to that of an LED light used for calibration was observed and showed stable intensity up to 6 min. Fiber surface analysis was tested using wettability tests (water contact angle and capillary uptake), while scanning electron microscopy, atomic force microscopy, and electron spectroscopy for chemical analysis showed changes in fiber surface morphology and chemical functional groups. A considerable increase in "N" atom content after coimmobilization of enzymes in the presence of BSA was detected. This study is the first successful attempt to use a biomimetic strategy for immobilization of enzymes involved in bacterial luminescence on a plasma-activated microfibrous nonwoven in an attempt to attain bioluminescent materials.

Inertial capillary uptake of drops.

Uptake of liquid drops into capillary tubes has been experimentally studied and quantitatively analyzed. In experiments, drops of water and aqueous glycerol (≤50 wt%) were drawn into cylindrical borosilicate glass and quartz tubes with an inner diameter of 0.50-0.75mm. The meniscus height rise was measured using high-speed images captured at 4000 frames per second, and results within a conservatively defined inertial regime indicate constant uptake velocity. An increase in the inertial velocity with drop curvature was observed due to increasing Laplace pressure in the drop, as drop sizes were comparable to the width of the capillary tubes. Measured velocities were slower than predicted by a purely inertial-capillary model and best described by introducing a contact line friction, consistent with the observed variability and viscosity dependence of the results. Mean friction coefficients in borosilicate capillaries ranged from 169±1 for 50 wt% glycerol drops to 218±1 for water drops. Peaks in the instantaneous Laplace pressure caused by surface oscillations were also measured. Correlations with uptake velocity were qualitatively apparent, with a delay between peaks of similar magnitude to the inertial-capillary oscillation time.

Effects of mussel shell aggregates on hygric behaviour of air lime mortar at different ages

Mussel shells, composed of calcium carbonate (>95%) and organic matter, are suitable alternatives to conventional sand in mortar. In addition, the use of lime instead of cement as a binder has also been considered for sustainable construction materials as well as in restorative applications.This study aims to contribute to the knowledge of air lime mortar through the analysis of the water transport properties of air lime mortar produced with mussel shell aggregates at different ages. Four mortar groups were obtained from the reference mortar by replacing limestone sand with mussel shell sand at substitution rates of 25%, 50%, and 75%. Water absorption, capillary uptake, weight variation, and drying from the fresh state up till one and two years were determined. The organic matter content and flaky seashell shape are responsible for the main differences observed between the mussel mortars and reference mortar. These two characteristics promote transport tortuosity paths and hydrophobic behaviour leading to reduced capillary uptake and increased drying resistance index. Furthermore, they enhance water retention, which increases the carbonation rate.

Capillary Uptake Monitoring in Lime-Hemp-Perlite Composite Using the Time Domain Reflectometry Sensing Technique for Moisture Detection in Building Composites.

The use of waste plants in the production of building materials is consistent with the principles of sustainable development. One of the ideas involves using hemp shives as an aggregate for the production of a composite used as a filling of the timber frame construction of the walls. The most important disadvantage of using the building materials based on organic components is their susceptibility to the water influence. The wall material is exposed to rising groundwater. The research part of the paper presented the preparation method and the investigation of the hemp-perlite-lime composites. Flexural and compressive strength, apparent density, total porosity, thermal conductivity, and mass absorptivity were examined. The main research part pertained to the analysis of capillary uptake occurrence in the composites, being the important phenomenon present in the external walls. The study on this phenomenon was carried out using the technique of indirect moisture evaluation—Time Domain Reflectometry (TDR). The indirect readouts were additionally verified with the traditional evaluation using the gravimetric method based on the PN-EN 1925 standard. The study proved that the tested composites were characterized by low apparent density, thermal conductivity, strength parameters, high total porosity, and mass absorptivity. The partial replacement of hemp shives by expanded perlite had a beneficial effect on the tested properties of composites.