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A novel approach exploiting surfaces and interfaces between liquid oils and porous soil media was used to investigate the role of xanthan gum (XG) in minimizing the spread of petroleum oil spills on land. 1.6 wt% XG added to soil‐based mixture matrixes (topsoil, sand, clay, and moisture) resulted in a 50% reduction in oil spreading area at 0 and 5 wt% moisture content, at 1.3 cm depth of soil matrix. Also recorded was a 45% increase in time taken for the low‐ and medium‐viscosity oils to penetrate this soil depth. XG alters the surface energy and roughness of the soil matrixes, which additionally contributes to a reduction in oil spreading capabilities. Interfacial phenomena between individual oil droplets and soil matrixes demonstrated variable findings of droplet spreading and penetration with XG, depending upon the heterogeneity of the soil matrix itself. XG assisted a reduced lateral spread in heterogeneous soil matrixes and a reduced vertical penetration in clay‐based matrixes. These interfacial results highlighted the often‐observed differing transport phenomena at the interface compared with the bulk. This initial study demonstrates a novel approach to incorporate surface energy phenomena into the suite of soil remediation efforts by introducing natural biopolymers in high‐risk land oil‐spill areas to slow oil contaminant spread. Future studies will further characterize the benefits of XG in containing oil flow. [ABSTRACT FROM AUTHOR]

Copper-based materials in combination with steels are of great interest for various applications in industry, such as tool manufacture, due to their high thermal conductivity. Additive manufacturing (AM) is beneficial for both tailored part geometry and customized material design. With laser-based AM, the copper-steel interface is highly prone to cracking. This study investigates a strategy of laser coating AISI H11 tool steel for a composite material consisting of AISI H11 tool steel and copper (H11/Cu) without using Ni-based interlayers. As an austenite stabilizing element, Ni dilution in H11 could lead to soft retained austenite, impeding wear resistance. The approach in this work employed presintering of tool steel powder to generate a porous H11 preform. Laser-based directed energy deposition (DED-LB/M) was used for coating H11 tool steel on the porous H11 preform followed by copper infiltration of the preform. The investigation of the effects of the main processing parameters: laser power, feed rate, and powder mass flow on the weld track geometry, clearly revealed different mechanisms when coating the porous preform compared to the conventional substrate. Defects at the coating/substrate interface such as cold crack formation were successfully avoided by adjusting the process parameters and process sequence. The developed processing strategy may in the future combine material extrusion of metals (MEX/M) and DED-LB/M to allow for intricate preform geometries and to generate H11 coatings on H11/Cu, respectively. [ABSTRACT FROM AUTHOR]

The free vibration analysis of a perovskite solar cell (PSC) within thermal environments is studied through a quasi-3D plate model. This model is designed to account for the stretching effects and non-uniform shear strains throughout the thickness. The PSC film is represented in the model as a thin laminated plate, comprising five distinct plies: ITO, PEDOT:PSS, perovskite, PCBM, and Au. A graphene platelets reinforced composite (GPLRC) substrate, made of Poly (methyl methacrylate), is assumed to be located under the noted five layers. The GPLRC substrate is conceptualized in the model as a porous foundation with finite depth. The foundation stiffnesses are determined using a modified Vlasov model, and the equivalent Young modulus of the foundation is evaluated using a modified Halpin–Tsai model, introducing the porosity coefficient. It is also considered that the material properties of GPLRC substrates exhibit temperature dependency. For the PSC with all edges simply supported, Navier solution method is applied to obtain the frequencies and associated mode numbers. Based on the results presented in this study, an increase in the porosity and thickness of the substrate can negatively impact the frequencies of the structure. However, natural frequencies experience almost no change if the temperature rises. [ABSTRACT FROM AUTHOR]

An analytical model for droplet impact onto a porous substrate is presented, based on Wagner theory. An idealised substrate boundary condition is introduced, mimicking the effect of fluid entry into a genuinely porous substrate. The asymptotic analysis yields a solution for a small porous correction with free-surfaces and pressures compared with the impermeable case. On a global scale, it is found that the impact region on the substrate grows more slowly with porosity included due to loss of mass into the substrate. The spatial distribution of liquid volume flux into the substrate is also described. Locally near the turn-over regions, the expected jetting along the surface is calculated with the same volume flux but the jet is found to be slower and thicker than for an impermeable substrate. [ABSTRACT FROM AUTHOR]

Commercialization of photoelectrochemical (PEC) water‐splitting devices requires the development of large‐area, low‐cost photoanodes with high efficiency and photostability. Herein, we address these challenges by using scalable fabrication techniques and porous transport layer (PTLs) electrode supports. We demonstrate the deposition of W‐doped BiVO4 on Ti PTLs using successive‐ionic‐layer‐adsorption‐and‐reaction methods followed by boron treatment and chemical bath deposition of NiFeOOH co‐catalyst. The use of PTLs that facilitate efficient mass and charge transfer allowed the scaling of the photoanodes (100 cm2) while maintaining ~90 % of the performance obtained with 1 cm2 photoanodes for oxygen evolution reaction, that is, 2.10 mA cm−2 at 1.23 V vs. RHE. This is the highest reported performance to date. Integration with a polycrystalline Si PV cell leads to bias‐free water splitting with a stable photocurrent of 208 mA for 6 h and 2.2 % solar‐to‐hydrogen efficiency. Our findings highlight the importance of photoelectrode design towards scalable PEC device development. [ABSTRACT FROM AUTHOR]

Vibration energy harvesting using piezoelectric cantilevers has been widely studied during the past decade. As an alternative to piezoelectric cantilevers, plate-like energy harvesters can be much more effective in marine, aerospace, and automotive applications. This work presents an exact two-dimensional model that can be used for analyzing thin, moderately thick, and thick piezoelectric bimorph plate vibration harvesters. The model allows to consider for the substrate layer both homogenous materials, and those with varying properties along the thickness direction. For the latter case, porous materials with various porosity distributions are herein considered, and the piezoelectric layers are assumed to be wired in both parallel and series configurations. Rayleigh damping assumptions are also used to model the structural damping of the harvesting system. Using Hamilton's principle and Gauss's law, the energy harvesting model is established based on the first-order and the third-order shear deformation theories. Applying an analytical procedure to the electromechanical governing equations, closed-form steady-state response expressions, which relate the voltage output and the vibration response of the harvester to harmonic input force, are derived. Finally, the proposed model is validated, and the power generation performance of the plate harvester is discussed through conducting extensive parametric studies, covering the effect of design parameters, such as the applied electric load, porosity characteristics, electrical configuration, and geometrical parameters. [ABSTRACT FROM AUTHOR]

Textile-based sensors fabricated using the direct-coating method are the appropriate choice to meet the aspects of flexibility, non-invasiveness, and lightness for continuous monitoring of the human body. The characteristics of the sensor substrate are directly influenced by factors such as the type of weave, thread fineness, fabric density, and the type of polymeric constituent fibers. The fabric used as the sensor substrate, fabricated using the direct-coating method, must be capable of retaining the electrode paste solution, which has higher viscosity, on one surface of the fabric to avoid short circuits during the fabrication process. However, during its application, this fabric should allow the easy passage of analyte solutions with low viscosity as much as possible. Hence, an appropriate fabric construction is required to serve as the substrate for textile-based sensors to ensure the success of the fabrication process and the effectiveness of the resulting sensor's performance. The development of the structural design of the fabric to be used as a substrate for non-invasive biosensors with a multilayer concept is carried out by weaving and sewing processes utilizing polyester-viscose fibers. During the production process, variations are applied, such as weft yarn density, the characterization of wetting time, absorption rate, maximum wetted radius, spreading speed, and accumulative one-way transport index. The most suitable fabric for use as a substrate for non-invasive biosensors with a multilayer concept, such as in this research, is a fabric with a weft thread density of 70 strands per inch, along with the addition of an analyte transfer thread configuration. [ABSTRACT FROM AUTHOR]

In the current study, we report the progress in developing new UV polymerizable hydrophobic biobased coatings from modified vegetable oil for porous substrates like paper and wood. The aim was to produce novel hydrophobic coatings on porous substrates and investigate how the porous nature of the substrates will be affected by different chemical formulations that penetrate into the interior of the substrate during the exposure to different intensities of UV light, and what hydrophobic properties that interaction will result in. The curing formulations were based on acrylated epoxidized linseed oil (AELO) as a prepolymer. For the UV polymerization, 1-hydroxycyclohexyl phenyl ketone (Irgacure 184) was used as a photoinitiator; isobornyl acrylate (IBA) and isosorbide methacrylate (IM) were used as bio-based diluents; hexadecyltrimethoxysilane (HDTMS), vinyl-polydimethylsiloxane (v-PDMS), triethoxyoctylsilane (TEOS) were used as hydrophobic additives and they were added in different concentrations to the AELO curing formulations. The formulations were then cured under UV light on wood and paper substrates. FT-IR analysis showed that the AELO resin was successfully polymerized on both paper and wood substrates, and by contact angle measurements it was found that the highest hydrophobicity was achieved for the coatings that contain HDTMS (108° in average). The layer thickness on wood substrates was in between 9 and 20 µm, and on paper substrates between 8 and 24 µm. Only about a 5° difference in contact angle was observed between the coatings with respect to change in diluents and different UV light intensity. All cured samples showed a good chemical resistance to acetic acid, citric acid and ethyl alcohol after 1 hour exposure; to acetone and ethylbutyl acetate after 10 s, and to benzine after 2 minutes. Outstanding hydrophobic behavior was observed for the HDTMS coatings, however, better physical properties were determined for the coatings containing v-PDMS and TEOS, on which the scratching was observed after the applied force of 1.5 and 0.6 N in comparison to HDTMS coatings (0.4 N). The resulting properties achieved for the AELO coatings indicated that it has a potential to be used for wood coating and packaging application. [ABSTRACT FROM AUTHOR]

How to simultaneously improve the ionic conductivity and mechanical properties is a key problem facing currently used anion-exchange membranes (AEMs). Here, biomass-based bacterial cellulose (BC) was used as a porous template to make TiO2 localized mineralization around the surface of BC nanofibers, and constructed a TiO2-coated BC porous substrate (TiO2@BC) with hierarchical structure. Then, the coated TiO2 nanoparticles was densely grafted by quaternary ammonium groups to obtain high ionic conduction ability. After filling with a polymeric ionic liquid (PIL) with high ion exchange capacity through in situ polymerization and crosslinking, the obtained novel PIL-filled AEM possessed ultrahigh ionic conductivity of 100.5 mS cm−1 at 80 °C, which was 72.1% higher than that of the PIL-filled pure BC membrane (only 58.4 mS cm−1). Moreover, by the aid of the synergistic reinforcement effect of TiO2@BC, the membrane exhibited extremely high dry strength of 95.3 MPa and satisfactory wet strength and flexibility. When at fully hydrate state, the membrane with the size of 1 × 4 cm (width × length) can hang a bottle containing 1000 g of water. The single cell equipped with this membrane output the peak power density of 40.2 mW cm−2, showing its great potential as a high-performance biomass-based AEM.

Porous germanium (PGe) nanostructures attract a lot of attention for various emerging applications due to their unique properties. Consequently, there is an increasing need for the development of low‐cost synthesis routes that are compatible with large‐scale production. Bipolar electrochemical etching (BEE) is a widely used solution for producing porous Ge layers. However, the lack of controllable production of large‐scale uniform PGe layers is the limiting factor for mainstream applications. Large‐scale homogeneous PGe layers formation is demonstrated by improving the BEE process. The PGe structures demonstrate excellent homogeneity in thickness and porosity, with a relative variation of below 2% across the 100 mm wafer. Furthermore, this process enables accurate tuning of the PGe's physical properties through variation of the etching parameters. PGe structures with porosity ranging from 40% to 80% and an adjustable thickness, while preserving low surface roughness are demonstrated, giving access to a large variety of PGe nanostructures for a wide range of applications. Ellipsometry and X‐ray reflectivity are employed to measure the porosity and thickness of PGe layers, providing fast and non‐destructive methods of characterization. These findings lay the groundwork for the large‐scale production of high‐quality PGe layers with on‐demand characteristics. [ABSTRACT FROM AUTHOR]

It remains an extreme challenge to fabricate artificial joint materials with applicability of mechanical properties compared with bones, superior biocompatibility, anti-friction and wear resistance performances. Here, we report an effective strategy to simultaneously enhance the anti-friction and wear resistance performance of Ti6Al4V substrate through optimizing the porosity and sputtering a high-entropy alloy (HEA) coating. The progressive scratch experiments are carried out to equivalently imitate the scratch deformation process induced by hard particles and evaluate the anti-friction and wear resistance performances, which directly reveal the significantly decreased coefficient of friction (COF) of porous substrate based on suitable pore diameter covered with HEA coating compared with pure Ti6Al4V substrate. The porous design is verified to effectively weaken the stress shielding effect and simultaneously improve the hydrodynamic lubrication. Attributed to the coupling effects of pore structure-induced “flexibility” and HEA coating-induced surface hardening, the composite structure exhibits low COF value, wear volume and enhanced scratch resistance. The design concept would facilitate the development of novel medical implant materials with requirements of anti-friction and wear resistance.

Semiconductor-based freestanding membranes (FSM) have recently emerged as a highly promising area of advanced materials research. Their unique properties, such as lightweight and flexibility, make them attractive for a wide range of disruptive device applications. However, the production of high-quality, single-crystalline FSM, especially from elemental materials such as germanium (Ge), remains a significant challenge. In this work, we report on the formation of easily detachable wafer-scale Ge FSM on porous Ge (PGe) substrate. The proposed method relies on low-temperature Ge epitaxy, allowing to preserve the porous structure's integrity during the FSM formation, and an easy substrate preparation for multiple reuses. Analysis of the surface morphology as a function of the deposited Ge thickness reveals that the FSM formation occurs in two distinct regimes. During the initial epitaxial regime, the Ge growth is governed by 3D nucleation on the PGe top surface. The nanoscale islands size increase, and consequent coalescence are found to increase the surface roughness up to a critical thickness, allowing full coalescence of islands into a 2D epilayer. The analysis of the membrane's surface morphology for various thicknesses shows continuous improvement, achieving sub nanometer surface roughness. Moreover, we demonstrate that the FSM formation process is applicable regardless the PGe porosity and thickness, while offering facile and sustainable substrate reconditioning for multiple FSM generation from the same substrate. Our findings open new opportunities to produce lightweight and flexible, high-performance optoelectronics based on Ge FSM, while ensuring reduction of both cost and critical materials consumption.

Abstract Porous germanium (PGe) nanostructures attract a lot of attention for various emerging applications due to their unique properties. Consequently, there is an increasing need for the development of low‐cost synthesis routes that are compatible with large‐scale production. Bipolar electrochemical etching (BEE) is a widely used solution for producing porous Ge layers. However, the lack of controllable production of large‐scale uniform PGe layers is the limiting factor for mainstream applications. Large‐scale homogeneous PGe layers formation is demonstrated by improving the BEE process. The PGe structures demonstrate excellent homogeneity in thickness and porosity, with a relative variation of below 2% across the 100 mm wafer. Furthermore, this process enables accurate tuning of the PGe's physical properties through variation of the etching parameters. PGe structures with porosity ranging from 40% to 80% and an adjustable thickness, while preserving low surface roughness are demonstrated, giving access to a large variety of PGe nanostructures for a wide range of applications. Ellipsometry and X‐ray reflectivity are employed to measure the porosity and thickness of PGe layers, providing fast and non‐destructive methods of characterization. These findings lay the groundwork for the large‐scale production of high‐quality PGe layers with on‐demand characteristics.

How to simultaneously improve the ionic conductivity and mechanical properties is a key problem facing currently used anion-exchange membranes (AEMs). Here, novel AEMs were prepared using quaternized bacterial cellulose (QBC) as a dual-functional substrate and then filled with a polymeric ionic liquid (poly(vinylbenzyl) trimethylammonium chloride, PVD) with high ion-exchange capacity through in situ polymerization and crosslinking. The dense quaternary ammonium groups grafted on the surface of BC nanofibers greatly increased the ionic conductivity, while the special three-dimensional network structure of BC significantly enhanced the tensile strength and chemical stability of the obtained PVD filled quaternized BC (QBC/PVD) membranes. The ionic conductivity of QBC/PVD membrane reached as high as 111 mS cm−1 at 80°C, which was 109% higher than that of the pure BC/PVD membrane (only 53 mS cm−1). Moreover, the QBC/PVD membrane exhibited extremely high dry strength of 72.3 MPa and satisfactory wet strength and flexibility, this membrane can hang a container containing 500 g of water when at fully hydrated state. The alkaline direct methanol fuel cell equipped with QBC/PVD output a peak power density of 64 mW cm−2, showing its great application potential as an AEM.

3D porous electrodes have been considered as a new paradigm shift for increasing the energy storage of pseudocapacitive micro-supercapacitors for on-chip electronics. However, the conformal deposition of active materials is still challenging when highly porous structures are involved. In this work, we have investigated the atomic layer deposition (ALD) of ruthenium dioxide RuO2 on porous Au and Pt architectures prepared by hydrogen bubble templated electrodeposition, with area enlargement factors ranging from 400 to 10 000 cm2/cm2. Using proper ALD conditions, a uniform RuO2 coverage has been successfully obtained on porous Au, with a specific electrode capacitance of 8.1 mF cmâˆ'2 and a specific power of 160 mW cmâˆ'2 for a minute amount of active material. This study also shows the importance of the chemical composition and reactivity of the porous substrate for achieving conformal deposition of a ruthenium oxide layer. [ABSTRACT FROM AUTHOR]

Diffusion dialysis (DD) for acid recovery is significantly restricted by the poor acid dialysis coefficient (UH+) of anion exchange membranes (AEMs). To overcome such problem, porous AEMs with extremely high free space volume have been fabricated herein based on porous membrane substrate, drawing inspiration from the dissolution‐diffusion concept. Specifically, chloromethylated polyethersulfone (CMPES) has been used as the starting material to create the porous substrate via non‐solvent phase inversion, then in‐situ crosslinked and quaternized using ethylenediamine (EDA) and N‐methylimidazole (NMI), respectively. In this study, the degrees of modification of EDA and NMI are controlled to adjust the microstructure and DD performance of the produced porous AEMs. The ideal AEM's UH+ and acid/salt separation factor (S) are 4.3 and 2.6 times greater, respectively, than those of the commercial DF‐120 membrane at the same condition. Additionally, it shows strong organic solvent resistance and thermal stability, and therefore demonstrate the potential for widespread use. [ABSTRACT FROM AUTHOR]

• The stability of LIBS detection of Sr in liquid is improved by using a foam titanium substrate. • The porous foam titanium substrate can suppress the influence of the CRE. • The RSD of the spectral intensity of Sr element reaches a minimum of 3.7%. In order to improve the stability of Laser-Induced Breakdown Spectroscopy (LIBS) detection of dried liquid droplets, a method using foam metal substrates to suppress the coffee ring effect (CRE) is proposed. Foam titanium is employed as the sample substrate, with irregular micropores and grooves on its surface. Due to the rapid infiltration of liquid droplets into the porous substrate and the diffusion of residual droplets on the foam titanium substrate, the capillary effect between the grooves and residual droplets effectively suppresses CRE. Analysis using the Washburn theory is conducted to explain the formation of CRE on titanium alloy substrates and the suppression of the coffee ring by foam titanium substrates. Two-dimensional line scans of rectangular dried liquid droplet samples on foam titanium, titanium alloy, filter paper, and polymethyl methacrylate (PMMA) substrates are performed using LIBS to verify the formation or suppression of CRE. The experiment analyzes the influence of foam titanium substrate pore size and thickness on detection stability. The results show that the relative standard deviation (RSD) of the Sr I 407.67 nm spectral intensity in foam titanium substrates with a thickness of 1.5 mm and pore size of 50 μm is the smallest (RSD = 3.7 %), which is lower than that of titanium alloy, filter paper, and PMMA substrates (RSD = 17 %, RSD = 6.7 %, RSD = 23 %, respectively), indicating that foam titanium substrates can effectively suppress the coffee ring effect. Four calibration curves for Sr I 407.67 nm on different substrates are established, and the fitting effect of foam titanium substrates is better, with a fitting coefficient R2 = 0.997 and ARSD = 5.3 %, and a limit of detection (LOD) of 0.48 μg/mL. The results indicate that foam titanium substrates can effectively suppress the coffee ring effect, improve the detection sensitivity and prediction accuracy of heavy metals, and provide a favorable reference for platform selection in the pretreatment process of LIBS technology. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) has attracted attention as an excellent membrane material for water treatment and desalination owing to its high mechanical strength, hydrophilicity, and permeability. In this study, composite membranes were prepared by coating GO on various polymeric porous substrates (polyethersulfone, cellulose ester, and polytetrafluoroethylene) using suction filtration and casting methods. The composite membranes were used for dehumidification, that is, water vapor separation in the gas phase. GO layers were successfully prepared via filtration rather than casting, irrespective of the type of polymeric substrate used. The dehumidification composite membranes with a GO layer thickness of less than 100 nm showed a water permeance greater than 1.0 × 10−6 mol/(m2 s Pa) and a H2O/N2 separation factor higher than 104 at 25 °C and 90–100% humidity. The GO composite membranes were fabricated in a reproducible manner and showed stable performance as a function of time. Furthermore, the membranes maintained high permeance and selectivity at 80°C, indicating that it is useful as a water vapor separation membrane.

The turbulent flow through a plane channel bounded by a single permeable wall is considered; this is a problem of interest since a carefully chosen distribution of grains and voids in the porous medium can result in skin friction reduction for the flow in the channel. In the homogenization approach followed here, the flow is not resolved in the porous layer, but an effective velocity boundary condition is developed (and later enforced) at a virtual interface between the porous bed and the channel flow. The condition is valid up to order two in terms of a small gauge factor, the ratio of microscopic to macroscopic length scales; it contains slip coefficients, plus surface and bulk permeability coefficients, which arise from the solution of microscale problems solved in a representative elementary volume. Using the effective boundary conditions, free of empirical parameters, direct numerical simulations are then performed in the channel, considering a few different porous substrates. The results, examined in terms of mean values and turbulence statistics, demonstrate the drag-reducing effects of porous substrates with streamwise-preferential alignment of the solid grains. [ABSTRACT FROM AUTHOR]

The production of natural astaxanthin is usually accomplished by suspended cultivation of the microalgae Haematococcus pluvialis. In this study, for the purpose of cost reduction, H. pluvialis is grown in pilot scale angled twin-layer porous substrate photobioreactors with light energy from red/blue LEDs that can produce red light, blue light, or a combination of blue-red light. The total dry biomass of the microalgae reached a maximum of 40.74 g.m-2 under blue-red LEDs. The early initiation of blue-red LED illumination (on day 2) after algae immobilization in the biofilm resulted in the highest accumulation of astaxanthin in the dry biomass, which reached a maximum of 1.3% (w/w) after 10 d of culture.

The turbulent flow through a plane channel bounded by a single permeable wall is considered; this is a problem of interest since a carefully chosen distribution of grains and voids in the porous medium can result in skin friction reduction for the flow in the channel. In the homogenization approach followed here, the flow is not resolved in the porous layer, but an effective velocity boundary condition is developed (and later enforced) at a virtual interface between the porous bed and the channel flow. The condition is valid up to order two in terms of a small gauge factor, the ratio of microscopic to macroscopic length scales; it contains slip coefficients, plus surface and bulk permeability coefficients, which arise from the solution of microscale problems solved in a representative elementary volume. Using the effective boundary conditions, free of empirical parameters, direct numerical simulations are then performed in the channel, considering a few different porous substrates. The results, examined in terms of mean values and turbulence statistics, demonstrate the drag-reducing effects of porous substrates with streamwise-preferential alignment of the solid grains.

A porous substrate plays an important role in constructing a thin-film composite forward osmosis (TFC-FO) membrane. To date, the morphology and performance of TFC-FO membranes are greatly limited by porous substrates, which are commonly fabricated by non-solvent induced phase separation (NIPS) or thermally induced phase separation (TIPS) processes. Herein, a novel TFC-FO membrane has been successfully fabricated by using cellulose triacetate (CTA) porous substrates, which are prepared using a nonsolvent-thermally induced phase separation (N-TIPS) process. The pore structure, permeability, and mechanical properties of CTA porous substrate are carefully investigated via N-TIPS process (CTAN-TIPS). As compared with those via NIPS and TIPS processes, the CTAN-TIPS substrate shows a smooth surface and a cross section combining interconnected pores and finger-like macropores, resulting in the largest water flux and best mechanical property. After interfacial polymerization, the obtained TFC-FO membranes are characterized in terms of their morphology and intrinsic transport properties. It is found that the TFC-FO membrane supported by CTAN-TIPS substrate presents a thin polyamide film full of nodular and worm-like structure, which endows the FO membrane with high water permeability and selectivity. Moreover, the TFC-FO membrane supported by CTAN-TIPS substrate displays a low internal concentration polarization effect. This work proposes a new insight into preparing TFC-FO membrane with good overall performance.

Metallization of polyethylene (PE) using thermal spray techniques has proved difficult due to its low melting point and softness. In this study, metallic coatings were applied on porous polyethylene substrates using a twin wire-arc spray process. Commercially available polyethylene sheets, 3 mm in thickness, were used as substrates. Copper (Cu), aluminum (Al), and zinc (Zn) were successfully deposited on the porous polymer, without prior surface preparation, to form coatings with thickness of about 400 µm. Coating surface morphology and cross-sections were examined using a scanning electron microscope. Individual metal splats on the porous and non-porous substrates were observed to study the differences in the bonding mechanisms. The adhesion strength and electrical resistivity of the coatings on porous PE were evaluated. It was found that the bond strength of all three metallic coatings was found to be higher than the ultimate fracture strength of the porous. These results suggest that porosity in the polymer helps to overcome the challenges of metallizing polyethylene and provides a significant reduction in the weight of the polymer. Therefore, all these properties aided in fabricating an extremely lightweight, composite material with potential use in thermal management applications. [ABSTRACT FROM AUTHOR]

Ion-exchange membranes (IEMs) are a core component that greatly affects the performance of electrochemical energy conversion processes such as reverse electrodialysis (RED) and all-vanadium redox flow battery (VRFB). The IEMs used in electrochemical energy conversion processes require low mass transfer resistance, high permselectivity, excellent durability, and also need to be inexpensive to manufacture. Therefore, in this study, thin-reinforced anion-exchange membranes with excellent physical and chemical stabilities were developed by filling a polyethylene porous substrate with functional monomers, and through in situ polymerization and post-treatments. In particular, the thin-reinforced membranes were made to have a high ion-exchange capacity and a limited degree of swelling at the same time through a double cross-linking reaction. The prepared membranes were shown to possess both strong tensile strength (>120 MPa) and low electrical resistance (2). As a result of applying them to RED and VRFB, the performances were shown to be superior to those of the commercial membrane (AMX, Astom Corp., Japan) in the optimal composition. In addition, the prepared membranes were found to have high oxidation stability, enough for practical applications.

This article presents the blade coating analysis of viscous nanofluid passing over a porous substrate using a flexible blade coater. Water-based copper nanoparticles are considered to discuss the blade coating process. The lubrication approximation theory is applied to develop the flow equations. The analytical solution is obtained for velocity, volumetric flow rate, and pressure gradient, while shooting method is applied to obtain the pressure, thickness, and load. Different models for dynamic viscosity have been applied to observe the impact of related parameters on pressure, pressure gradient, and velocity. These results are presented graphically. Interesting engineering quantities such as load, deflection, and thickness are computed numerically and are shown in the tabulated form. It is found that nanoparticle volume fraction increases the pressure gradient, pressure and has minor effects on velocity. For model 1, an increase in the volume fraction reduces the coating thickness, load, and deflection, while model 2 has opposite effects on the mentioned quantities. Also, model 2 has a greater impact on pressure and pressure gradient when compared to model 1. [ABSTRACT FROM AUTHOR]

The thickness of an ultrathin blocking layer for anodic aluminum oxide (AAO)-supported thin-film solid oxide fuel cells is determined. The atomic layer-deposited (ALD) ultrathin yttria-stabilized zirconia (YSZ) blocking layer for gadolinia-doped ceria (GDC) electrolyte cell is deposited on 300 nm-thick Pt anode-coated AAO substrates. The surface of AAO substrates is examined to be non-uniform in terms of pore size and bump inclination by field emission scanning electron microscopic analysis. While the average pore size is 130 nm, the pore size ranges from 36 to 207 nm. While the average slope angle is 42°, the slope angle ranges from 9° to 79°. A growth modelling result considering the pore sizes and the slope angles presents that highly reliable ALD-deposited YSZ blocking layers need to be thicker than 93 nm. This prediction well corresponds to the evolution of open circuit voltages for 400 nm-thick GDC electrolyte cells with 60 nm-thick and 120 nm-thick ALD-deposited YSZ blocking layers. [ABSTRACT FROM AUTHOR]

Commercialization of photoelectrochemical (PEC) water-splitting devices requires the development of large-area, low-cost photoanodes with high efficiency and photostability. Herein, we address these challenges by using scalable fabrication techniques and porous transport layer (PTLs) electrode supports. We demonstrate the deposition of W-doped BiVO 4 on Ti PTLs using successive-ionic-layer-adsorption-and-reaction methods followed by boron treatment and chemical bath deposition of NiFeOOH co-catalyst. The use of PTLs that facilitate efficient mass and charge transfer allowed the scaling of the photoanodes (100 cm 2 ) while maintaining ~90 % of the performance obtained with 1 cm 2 photoanodes for oxygen evolution reaction, that is, 2.10 mA cm -2 at 1.23 V vs. RHE. This is the highest reported performance to date. Integration with a polycrystalline Si PV cell leads to bias-free water splitting with a stable photocurrent of 208 mA for 6 h and 2.2 % solar-to-hydrogen efficiency. Our findings highlight the importance of photoelectrode design towards scalable PEC device development., (© 2023 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Foams have recently been characterised as ideal products for pharmaceutical and topical use applications for the delivery of topical active agents. Foams are usually produced in a wet form but in a number of applications moderately dry foams are required. Drying of foam under terrestrial conditions proceeds under the action of gravity, which is impossible under microgravity condition. Below a new method of drying foams under microgravity condition is suggested. According to this method foam should be placed on a porous support, which will absorb the liquid from foam based on capillary forces only. The final liquid content inside the foam can be achieved by a proper selection of the porous support. The suggested method allows drying foams under microgravity conditions. Interaction of foams with porous support under terrestrial conditions was developed only recently and theoretically investigated (Arjmandi-Tash, O.; Kovalchuk, N.; Trybala, A.; Starov, V. Foam Drainage Placed on a Porous Substrate. Soft Matter2015, 11 (18), 3643–3652) followed by a theory of foam drainage on thin porous substrates (Koursari, N.; Arjmandi-Tash, O.; Johnson, P.; Trybala, A.; Starov, M. V. Foam Drainage Placed on Thin Porous Substrate. Soft Matter, 2019, (submitted)), where rate of drainage, radius of the wetted area inside the porous layer and other characteristics of the process were predicted. The latter model is modified below to investigate foam drying under microgravity conditions. Model predictions are compared with experimental observations for foam created using Triton X-100 at concentrations above CMC. Wetted radius inside the porous substrate was measured and results were compered to model predictions. Experimental observations for spreading area versus time show reasonable agreement with theoretical predictions for all investigated systems. [ABSTRACT FROM AUTHOR]

Tailoring pore-creating method to fit the various demands of different researchers is the frontier issue in the research of electrode capacitance of boron-doped diamond (BDD). Two critical factors in achieving the desired capacitance are the pore size and shape. This work compares the characteristics and applicability of various pore-creating methods, and reveals the influence mechanism of factors such as surface area, size and shape of the pore, on the capacitance of BDD electrodes. Obtained results could facilitate researchers to develop a personalized pore-creating method to achieve the desired capacitance. [ABSTRACT FROM AUTHOR]

Highlights • Simultaneous thermal and hydraulic improvement of double layer MCHS is shown. • Figure of merit is used to consider heat transfer and pressure drop simultaneously. • Optimum designs are revealed at different porosities, flow rates, and materials. Abstract Effect of utilizing porous substrates on thermal and hydraulic performance of double-layered microchannel heat sinks (MCHSs) is comprehensively analyzed in this work. Thermal resistance and pumping power of the porous double layer MCHSs are evaluated to find optimized designs which improve heat transfer while requiring lower pumping power compared to conventional MCHSs. Conjugate heat transfer is numerically simulated by developing three dimensional models of porous MCHSs with different solid and porous fin thicknesses at the top and bottom channels. For design optimization, various performance parameters are evaluated and compared to conventional microchannels by changing the porous substrate and solid fin thickness. The results show that for every combination set of geometrical parameters in double-layered MCHS, an optimized porous double-layered MCHS can be found which can enhance thermal and hydraulic performance. Studying the heat transfer effectiveness and pumping power effectiveness of the new porous double-layered MCHSs simultaneously indicate this. The enhancement is shown in all scenarios where the top and bottom channel can have different solid-porous thickness. The superior performance of porous double-layered microchannels is verified for different range of Reynolds number, porosity of substrates, and heat sink material. [ABSTRACT FROM AUTHOR]

In the investigation of criminal cases involving metallic weapons such as firearms and knives, the trace metal detection test (TMDT) and the transfer detection technique are two effective and on-the-spot methods to link a suspect and a suspected metallic weapon. In general, these tests need to be conducted on suspects' hands or done by lifting trace metals from their hands within 3 days of the crime being committed. However, if no suspects are arrested within this period, neither of these two techniques is applicable. This paper presents preliminary development of a modified TMDT to overcome the intrinsic disadvantages of conventional TMDTs. The method primarily focuses on the secondary imprints on porous substrates that are transferred unconsciously from the palms of criminals after handling galvanized weapons. The modified TMDT was established by studying the effect of various factors on secondary imprints on porous substrates. We also tested the effectiveness of the modified TMDT for common porous substrates and galvanized weapons and its relative sensitivity in a depletion series. Additionally, the storage conditions of the developed secondary imprints as physical evidence were studied under different time lapses and light conditions. Finally, we proposed an improved procedure for detecting metal traces formed in the use of metallic weapons and subsequent activities at a crime scene. The modified TMDT provides a novel method for investigators to demonstrate the relationship between a suspect and a metallic weapon, thus reducing the heavy reliance of conventional TMDTs on suspects and the time limit available to visualize or lift metal traces. For this reason, it can be used as a complementary and remedial method for conventional TMDTs, especially when suspects are not arrested within 3 days of the commission of a crime. Furthermore, the improved procedure can serve as a guide for investigators to apply the TMDT series properly to solving the cases involving metallic weapons. [ABSTRACT FROM AUTHOR]

In this paper we propose a mathematical and physical model of a porous substrate, evaluate influence of the pores size and quantity on the substrate's specific surface and present experimental results of the heat leakage kinetics by the porous substrate. Performances of the porous aluminium oxide printed circuit board with the record heat conductivity of 120 W/mK are presented. [ABSTRACT FROM AUTHOR]

An anode-supported honeycomb SOFC gives high volumetric power density and improves thermo-mechanical durability at high temperatures. We have so far fabricated and tested a honeycomb cell with a cathode layer of LSM and an electrolyte layer of 8YSZ on a porous anode honeycomb substrate of Ni/8YSZ. The anode-supported honeycomb cell exhibited promising volumetric power densities. In the present study, current-voltage and current-volumetric power density characteristics of the cells having different flow channel arrangements of the anode and cathode are measured under various inlet hydrogen fuel flow rates to show the effect of three-dimensional transport and distribution of the fuel in the porous anode substrate on the cell performance. We measure ohmic resistances of the honeycomb cells by current interruption method, and indicate the impact of nickel catalyst re-oxidation in the anode substrate by the fuel depletion with the flow channel arrangements resulting in high ohmic resistances and deactivation of the nickel catalyst. In low inlet fuel flow rate, smaller number of the anode flow channel is thereby advantageous, while larger number of the anode flow channel is advantageous in high inlet fuel flow rate. We also discuss suitable flow channel arrangements depending on inlet fuel flow rate to choose an appropriate operation mode.

Physical Developer (PD) is an underutilized technique for the development of latent marks on porous surfaces that have been wet, or as a subsequent technique in a development sequence. It is a multistep technique that works by selectively reducing silver ions to silver metal at nucleating sites in fingermark residue. Its use is associated with a plethora of issues, largely surrounding the inherent instability of the working solution. Recently, one of the components of the working solution, Synperonic N, has ceased production, and the recommended replacement is Tween 20. This article addresses factors during PD processing using Tween 20, other than reagent formulations that should be considered when using the technique. [ABSTRACT FROM AUTHOR]

Highlights • The sonophotocatalytic decolorization of a toxic dye was evaluated via 3D-PS/nphs. • Two different nphs were fabricated on each side of the 3D-PS by sonoloading process. • Response surface methodology (RSM) was used to optimize the decolorization process. • Begazol Black B was completely decolorized by 3D-PS/nphs at 40 min. • Sonoloaded nphs on the 3D-PS were shown 93% durability after 50 h treatment. Abstract In this study, sonophotocatalytic decolorization of Begazol Black B by double-sided, sonoloaded nanophotocatalysts (nphs) on 3D porous substrate (3D-PS) was reported for the first time. Sonoloading is a facile fabrication route that allows two-sided loading of nphs on 3D-PS. Morphology of the 3D-PS and the presence of the nphs were studied using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Moreover, the durability of the nphs on the 3D-PS was studied using X-ray fluorescence. The central composite design based on response surface methodology was employed to find the maximum yield of sonophotocatalytic decolorization and optimize the process variables (initial BBB concentration, initial H 2 O 2 concentration, pH and ultrasonication time). Complete decolorization was achieved at only 40 min treatment under the optimum conditions. Moreover, sonoloaded nphs on 3D-PS exhibited 93% durability after 50 h sonophotocatalytic decolorization. The anticipated values of the decolorization efficiency showed excellent agreement with the experimental values (R 2 = 0.9823, Adj- R 2 = 0.9657). Furthermore, the kinetic analysis demonstrated that the sonophotocatalytic decolorization followed the Langmuir-Hinshelwood kinetic model. Finally, a comparative study between sonocatalytic, photocatalytic and sonophotocatalytic processes was conducted at the optimum condition. The results revealed that sonophotocatalytic process can markedly enhance the decolorization efficiency compared to sonocatalytic and photocatalytic methods due to the enhanced reactive radical generation. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

A comprehensive study utilizing porous substrates in microchannel heat sinks (MCHS) is presented in this work to find an optimized design which improves thermal and hydraulic performance of conventional microchannels. Three dimensional models of MCHS with different solid and porous fin thicknesses have been analyzed in this work. A parametric optimization has been done on the thickness of the solid and porous fin, and various performance parameters are evaluated for different MCHSs. The results are compared with the conventional heat sinks and demonstrate that for every combination set of MCHS geometrical parameters, there is an optimized porous design which can improve the thermal and hydraulic performance at the same time, or at least improving one while keeping the other at the same level as a conventional heat sink. This improvement is examined for different ranges of Reynolds numbers and pumping powers. Optimization process has been applied for porous MCHSs with various heat sink material and porosities. The superior effect of optimized porous design has been observed in all cases. [ABSTRACT FROM AUTHOR]

Lab-on-Chip is currently considered the technology with the potential to revolutionize future biochemical analysis providing miniaturized, low-reagent volume microchips as an alternative to traditional benchtop analysis. Automated control of droplet flow is currently a key objective in microfluidics research, aiming for droplet logic microfluidic circuits. To this end, microfluidic research has been following the electronics paradigm, with several digital fluidic components being demonstrated towards the realization of digital fluidic circuits for automated liquid control and delivery. In this work, we introduce a new concept of microfluidic pressure controlled field-effect transistors (pFETs), towards droplet logic operations. Using a fluidic with porous and hydrophobic walls, the inherently pinned plug depins by pressure application through the porous wall (backpressure), thus enabling the actuation and the downward transportation of the plug due the action of gravity. This concept resembles the logic operation of a metal–oxide–semiconductor field-effect transistor (MOSFET). The pFET operating parameters are thus defined in a manner analogous to MOSFET digital switches and their dependence on the channel width is studied also for the first time. The successful operation of pFET devices for droplet logic operation is verified in continuous ON/OFF cycles, achieving OFF-ON and ON-OFF switching times under 1 s (0.864 s and 0.841 s respectively) and therefore promising rapid liquid switching times, comparable to electronic circuit ones. [ABSTRACT FROM AUTHOR]

Two-ply composite membranes with separation layers from chitosan and sulfoethylcellulose were developed on a microporous support based on poly(diphenylsulfone-N-phenylphthalimide) and investigated by use of X-ray diffraction and scanning electron microscopy methods. The pervaporation properties of the membranes were studied for the separation of aqueous alcohol (ethanol, propan-2-ol) mixtures of different compositions. When the mixtures to be separated consist of less than 15 wt % water in propan-2-ol, the membranes composed of polyelectrolytes with the same molar fraction of ionogenic groups (-NH3+ for chitosan and -SO3- for sulfoethylcellulose) show high permselectivity (the water content in the permeate was 100%). Factors affecting the structure of a non-porous layer of the polyelectrolyte complex formed on the substrate surface and the contribution of that complex to changes in the transport properties of membranes are discussed. The results indicate significant prospects for the use of chitosan and sulfoethylcellulose for the formation of highly selective pervaporation membranes. [ABSTRACT FROM AUTHOR]

A novel metal-organic framework film MIL-124 film was prepared on porous α-Al 2 O 3 ceramic plate by in situ synthesizing. After introducing Eu 3+ ions to the free -COOH sites of the MIL-124 ligand channels, a luminescent MOF film MIL-124@Eu 3+ was obtained. Based on the chemical reaction between NH 3 and the -COOH, the formation of -COONH 4 which was demonstrated by FT-IR spectrum, affected the energy transfer between Eu 3+ ions and ligand, quenching the characteristic emission of MIL-124@Eu 3+ film. The limit of detection to ammonia was calculated as 26.2 ppm in ambient air. The XRD results demonstrated the long-term stability of this ammonia sensor. The excellent performance and economical synthesizing strategy of the MIL-124@Eu 3+ film exhibited potential application of this sensor for detecting ammonia gas. [ABSTRACT FROM AUTHOR]

In this paper the effects of the suspension preparation conditions on suspension coating of porous substrates were investigated. Alumina suspensions were prepared using varying types of additives, including non-ionic polyethylene glycol (PEG), cationic polyethylene imine (PEI), and anionic sodium carboxymethyl cellulose (CMC). Prepared suspensions were coated on porous SiC substrates by spin coating. The flow curves of the suspensions were measured, whereas their particle dispersion states were also observed directly using an optical microscope. In addition, the surface and cross-section of each coating were observed by SEM and analysed by EDX. Finally, the air permeability of each coating was measured. For the suspension with PEG, alumina particles dispersed well in the suspension and the added PEG formed a network structure, resulting in a homogeneous coating on the surface of the substrate with less particle penetration into the substrate pores. For the suspension with CMC and the suspension with PEI, since particles flocculated in the suspensions, particle penetration into the substrate pores hardly occurred, however, the formed coating was inhomogeneous. [ABSTRACT FROM AUTHOR]

At the core of translational challenges in tissue engineering is the mechanistic understanding of the underpinning biological processes and the complex relationships among components at different levels, which is a challenging task due to the limitations of current tissue culture and assessment methodologies. Therefore, we proposed a novel scale-down strategy to deconstruct complex biomatrices into elementary building blocks, which were resembled by thin modular substrate and then evaluated separately in miniaturised bioreactors using various conventional microscopes. In order to investigate cell colonisation within porous substrate in this proof-of-concept study, TEM specimen supporters (10-30 μm thick) with fine controlled open pores (100∼600 μm) were selected as the modular porous substrate and suspended in 3D printed bioreactor systems. Noninvasive imaging of human dermal fibroblasts cultured on these free-standing substrate using optical microscopes illustrated the complicated dynamic processes used by both individual and coordinated cells to bridge and segment porous structures. Further in situ analysis via SEM and TEM provided high-quality micrographs of cell-cell and cell-scaffold interactions at microscale, depicted cytoskeletal structures in stretched and relaxed areas at nanoscale. Thus this novel scaled-down design was able to improve our mechanistic understanding of tissue formation not only at single- and multiple-cell levels, but also at micro- and nanoscales, which could be difficult to obtain using other methods. [ABSTRACT FROM AUTHOR]