SH Surface Research Articles

Copper nanoclusters-doped novel carrier with synergistic adsorption-catalytic active sites to enable high-performance dye removal

Enhancing the synergistic interplay between adsorption and catalytic oxidation to amplify Fenton-like effects remains a pivotal challenge in advancing water pollution remediation strategies. In this study, a suite of novel carriers (SH) composed of silica (SiO2) and hydroxyapatite (HAp) in different ratios were synthesized through an amalgamation of the sol–gel and co-precipitation techniques. Notably, various forms of copper (Cu) species, including Cu2+ ions and Cu nanoclusters (Cu NCs), could be stably incorporated onto the SH surface via meticulous loading and doping techniques. This approach has engendered a new class of Fenton-like catalysts (Cu NCs-SH1-5) characterized by robust acid-base tolerance stability and remarkable recyclability. Compared with the previously reported Cu NCs-HAp, this catalyst with lower Cu species content could achieve better performance in adsorbing and degrading dyes under the aid of hydrogen peroxide (H2O2). The catalyst's dual action sites, specifically the adsorption sites (SiOH, POH, slit pores) and catalytic centers (multivalent Cu species), had clear division of labor and collaborate with each other. Further, reactive oxygen species (ROS) identification and astute electrochemical testing have unveiled the mechanism underpinning the cooperative degradation of dyes by three types of ROS, spawned through electron transfer between the Fenton-like catalyst (Cu NCs-SH) and H2O2. From these insights, the mechanism of synergistic adsorption-catalytic removal was proposed.

A Unified Model for Investigating the Propagation of SH Surface Waves in a Piezoelectric Layered Medium

In this paper, a thorough analysis is conducted to examine the propagation characteristics of SH surface waves in a layered medium with a nanoscale piezoelectric guiding layer deposited on an isotropic elastic substrate. Specifically, a two-dimensional analytical model is established, within which the effects of strain gradient, electric field gradient, inertia gradient, and flexoelectricity are considered, as well as interfacial imperfections at the interface between the piezoelectric guiding layer and the elastic substrate, which are characterized by spring models. Within the framework of the variational principle, the governing equations, boundary conditions, and continuity conditions at the interface are derived. Based on these equations, the dispersion relations for SH surface waves are deduced and numerically solved for both the electrically open-circuit and electrically short-circuit cases. A comprehensive investigation of the dispersion relations for the fundamental mode of SH surface waves is subsequently provided, with a detailed discussion on the influence of critical factors. The developed theoretical model, encompassing various size effects observed in nano-scale structures, enables a more precise prediction of surface wave propagation behavior, thereby enhancing the design and application of surface acoustic wave devices.

Insights into emulsion synthesis of self-assembled suprastructures formed by Janus silica particles with -NH2/-SH surface groups.

Spherical particles with tunable anisotropic structures enabled by multiple surface functionalities have garnered interest for their potential applications in adsorption technologies. The presence of diverse functional groups in the surface layer, exhibiting varying acidity and hydrophilicity, can lead to unique characteristics in terms of surface structure and behaviour. In this study, the particles were synthesised using a two-step approach involving surface functionalisation of previously synthesised SiO2 Stöber particles. This was achieved by employing 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-aminopropyltrimethoxysilane (APTMS) in a toluene-in-water emulsion. The resulting particles were found to be nonporous, with a specific surface area of 8 m2 g-1. Their sizes were determined to be up to 350 nm through photon cross-correlation spectroscopy. Moreover, the particles exhibited a high net content of functional groups (both amino and mercapto) of 2 mmol g-1. The organisation of the particles during synthesis was observed through SEM images, providing insights into their structural characteristics. Additionally, the study of Eu(iii), Au(iii), and Ag(i) ions and fluorescein adsorption demonstrated varying interactions on the surface, highlighting the potential applications and versatility of these functionalised particles.

Understanding the self-pinning driven jamming behavior of colloids in drying droplets

The jamming of the colloids in a dried droplet is influenced by various parameters, where substrate wettability is notably crucial. Evaporating a sessile droplet on a wettable surface advances the pinning of the contact line which leads to the enhancement in the velocity of colloidal particles during the drying of the droplet (Marin et al., 2011). Now, the question arises: will the jamming of the colloidal particles in the case of evaporation of a droplet on the superhydrophobic surface (SH) and air-suspended spray colloidal droplet exhibit the increase in velocity of colloidal particles during drying of the droplet? The drying arrangement of the colloidal particles has been probed using electron microscopy and small-angle X-ray scattering. The fast Fourier transform of the electron microscopy images has been established utilizing ImageJ software. The supraparticles resulting from the evaporation of the droplet on the SH surface as well as by spray drying demonstrated a localized ordered arrangement on the outer surface whereas the arrangement becomes random in the inner region. The transition from ordered to the random arrangement of colloidal particles from the outer region to the inner region is due to the increase in the velocity of the colloidal particles during evaporation. The increase in the velocity can be attributed to the self-pinning of the colloids at the water-air interface resulting in elastic shell formation due to the locking of the colloidal particles in Van der Waals minima. Due to the presence of the menisci between the colloids, the formed shell behaves as nanomembrane, and the evaporation of the solvent through these nanopores accelerates and results in an increase in the velocity of the colloidal particles. Further, increasing polydispersity in the size of colloids led to random disordered jamming even on the top surface of the dried supraparticles.

Resonance frequency of an orthotropic layer to non-principal vertically incident SH body and surface waves

Resonance frequency of an orthotropic layer to non-principal vertically incident SH body and surface waves

The effect of high-voltage electrostatic field on the interactions between duck myofibrillar protein and inulin: An underlying mechanisms study

This study investigated the effect of high-voltage electrostatic field (HVEF) treatment on the interactions between duck myofibrillar protein (MP) and inulin, as well as explored the gel properties of adding inulin to duck MP. Hence, different inulin content (0–30 mg mL−1) were added to duck MP and HVEF treatment was applied in the gelation process.The results revealed that HVEF combined with the addition of 30 mg mL−1 inulin treatment significantly increased (P < 0.05) the water holding capacity and gel strength by 0.20 and 2.61 times, respectively. Moreover, the rheological characteristics and the formation of the three-dimensional network structure was promoted after added inulin and applied HVEF treatment. The HVEF treatment in modifying MP-inulin interaction promoted the conversion of α-helix to β-sheet, β-turn and random coil, significantly increased (P < 0.05) the content of R–SH groups and surface hydrophobicity, thus revealing the underlying mechanisms of the enhancement of duck MP gel performance. Principal component analysis revealed these interrelationships. This data demonstrated that inulin addition combined with HVEF treatment might be a new and effective strategy to enhance the duck MP gel properties.

Semi-analytical solution for the elastic wave propagation due to a dislocation source in a transversely isotropic half-space

SUMMARY In this paper, the 3-D theoretical seismogram at the free surface of an elastic half-space with ‘vertical transverse isotropy (VTI)’ and an ‘elliptic anisotropy‘ is synthesized via semi-analytical formulation. To this end, the time-domain solution is obtained via the Hankel and Laplace integral transforms and the Cagniard contour integration scheme. The formulations include complete Green's functions expressed in compact and elegant formulations in terms of some elementary line integrals over the finite interval (0, π/2), due to the general point force and point double-couple source of arbitrary orientation, varying with time as Heaviside step function. This solution is further implemented to model seismic waves generated from moment tensor source with a ramp-type slip function. The solution clearly delineates compressional P waves, shear SV waves and SH waves, diffracted SPwaves and surface Rayleigh waves, with two critical distances in which the mode conversion happens. The first marks the conversion of the total reflection of SV wave into the diffracted SPwave travelling on the free surface with the velocity of compressional wave. The second, however, marks a location where the order of arrival times of SP and SH waves is reversed. The interesting phenomenon of shear wave splitting by the apparent time lag between the arrivals of SV and SHwaves is further demonstrated. Studied also is the effect of non-double-couple (non-DC) components of the moment tensor of the shear fault. Particularly, it is shown that non-DC components may lead to large amplitude of the P wave in the presence of anisotropy, resulting in the changed polarity of P wave at the onset of the motion. It is found that for the elliptic anisotropy, and for oblique-thrust faults, the isotropic moment (ISO) is always negative if the elastic constants satisfy C11 &amp;gt; C33 and C44 &amp;gt; C66, whereas it is always positive if C11 &amp;lt; C33 and C44 &amp;lt; C66 (for oblique-reverse faults, the situation is reversed). It is shown that for some sedimentary rocks, the decomposition of moment tensor in the general VTI and in its elliptic approximation are close to each other, and that the moment tensor decomposition in VTI media is very sensitive to the elastic coefficients, such that a small change in the elastic constants may lead to a remarkable change in the moment tensor decomposition. Particularly, the effect of elastic constant C13 is shown to be significant. While the time-domain solution obtained in this paper can be also degenerated to the solution in the corresponding isotropic half-space, the Mathematica code of the solution provided can be served as benchmark to other numerical solutions, applicable for the computation of the theoretical seismogram in the involved media.

A review focused on the superhydrophobic fabrics with functional properties

AbstractSuperhydrophobic (SH) property is a naturally occurring phenomenon that has a wide range of potential applications such as antiicing, anticorrosion, electrowetting, blood typing, and so forth, and therefore, inspires the researchers to mimic them over artificial surfaces to achieve desired properties. Low surface energy and suitable surface roughness are the two key factors that play a vital role in developing SH surfaces. Hence, when the target substrate is introduced with suitable roughness and consequently functionalized with low surface energy, SH can be incorporated. Owing to the SH's wide range of inherent properties such as stain‐resistant, self‐cleaning, flame retardant, oil/water separation, and so forth as well as tunable functionalities such as electrical conductivity, photocatalytic activity, UV‐protection, and so forth, the development of SH fabrics has gained a lot of research attention in recent years. In this context, the present review focuses on the different applications of SH fabrics and their recent research progress.

Improved gelling and emulsifying properties of myofibrillar protein from frozen shrimp (Litopenaeus vannamei) by high-intensity ultrasound

The deterioration of shrimp protein functionality during chilling and frozen storage has recently attracted wide attention due to its adverse effects on shrimp quality. The high-intensity ultrasound (20 kHz, 400 W) was applied to improve the protein structure and functional properties of frozen shrimp ( Litopenaeus vannamei ) in this study. Fourier transform infrared (FTIR) spectroscopy showed that the cavitation effect of ultrasound could change the secondary structure of myofibrillar protein (MP) by turning the α-helix and random coil to β-sheet and β-turn. The unfolding of MP conformation increased the reactive sulfhydryl content and surface hydrophobicity accordingly. The structure changes eventually led to the significant improvement of protein functionality. Gel properties analysis showed after ultrasonic treatment, the gel strength and water holding capacity of protein gels were increased gradually. Scanning electron microscopy (SEM) images also demonstrated that ultrasound treatment contributed to the formation of stable network structures in protein gels. In addition, ultrasonic homogenization could increase the emulsifying ability (45.54 m 2 /g to 78.82 m 2 /g) and stability of protein in a short time, which might be related to the decrease of particle size. Confocal laser scanning microscope (CLSM) analysis further illustrated that ultrasound treatment made the emulsion distribution more uniform. The application of these findings will improve the deep processing ability and expand the commercialization of frozen shrimp products. • Ultrasonic treatment led to the unfolding of shrimp MP conformation. • Conformational change led to the increase of SH groups and surface hydrophobicity. • Ultrasound increased gel strength and water holding capacity of shrimp MP gel. • Ultrasound increased the emulsifying capacity and stability of frozen shrimp MP. • CLSM analysis illustrated ultrasound made emulsion distribution more uniform.

Improving the Functional Performance of Date Seed Protein Concentrate by High-Intensity Ultrasonic Treatment.

Date kernel is a plant-derived byproduct that has the potential to be converted into a high-value-added food ingredient, such as protein concentrate, in the food industry. Ultrasound, which is an alternative method for improving the functional properties of food proteins, is an effective physical treatment for modifying protein functionality. Solubility is the main criterion that primarily affects other functional properties of protein concentrates, such as emulsification, foaming, and water and oil binding. The aim of this study is to enhance the techno-functional performance of date seed protein concentrate (DSPC) by maximizing the solubility via a high-intensity ultrasound (HIUS) treatment at a fixed frequency of 20 kHz. The effect of ultrasonic homogenization under varying amplitudes and times (amplitude of 40, 60, and 80% for 5, 10, and 15 min, respectively) on the functional properties of the DSPC was investigated by using the response surface methodology (RSM). A face-centered central composite design (FC-CCD) revealed that the optimal process conditions of HIUS were at an amplitude of 80% for 15 min. The physicochemical and functional properties of the ultrasound-applied concentrate (DSPC-US) were determined under the optimum HIUS conditions, and then these properties of DSPC-US were compared to the native DSPC. The results showed that the solubility of all DSPC samples treated by HIUS was significantly (p &lt; 0.05) higher than that of the native DSPC. In addition, emulsion activity/stability, foaming activity/stability, and oil-binding capacity increased after HIUS homogenization treatments, whereas the water-binding capacity decreased. These changes in the techno-functional properties of the DSPC-US were explained by the modification to the physicochemical structure of the DSPC (particle size, zeta potential, SDS-PAGE, SEM, FTIR, DSC, free SH content, surface hydrophobicity, and intrinsic emission). This work revealed that HIUS could be an effective treatment for enhancing the functional properties of date seed protein concentrate.

Impacts of sonication and high hydrostatic pressure on the structural and physicochemical properties of quinoa protein isolate dispersions at acidic, neutral and alkaline pHs.

Herein, 1wt% quinoa protein isolate (QPI) was exposed to sonication using a 20kHz ultrasonicator equipped with a 6mm horn (14.4W, 10mL, up to 15min) or high hydrostatic pressure (HHP, up to 600MPa, 15min) treatments at pH 5, pH 7, and pH 9. The changes to physicochemical properties were probed by SDS-PAGE, FTIR, free sulfhydryl group (SH), surface hydrophobicity (H0), particle size and solubility. As revealed by SDS-PAGE, substantial amounts of 11S globulin participated in the formations of aggregates via SS bond under HHP, particularly at pH 7 and pH 9. However, protein profiles of QPI were not significantly affected by the sonication. Free SH groups and surface hydrophobicity were increased after the sonication treatment indicating protein unfolding and exposure of the embedded SH and/or hydrophobic groups. An opposite trend was observed in HHP treated samples, implying aggregation and reassociation of structures under HHP. HHP and sonication treatments induced a decrease in ordered secondary structures (random coil and β-turn) accompanied with an increase in disordered secondary structures (α-helix and β-sheet) as probed by FTIR. Finally, the sonication treatment induced a significant improvement in the solubility (up to ∼3 folds at pH 7 and ∼2.6 folds at pH 9) and a reduction in particle sizes (up to ∼3 folds at pH 7 and ∼4.4 folds at pH 9). However, HHP treatment (600MPa) only slightly increased the solubility (∼1.6 folds at pH 7 and ∼1.2 folds at pH 9) and decreased the particle size (∼1.3 folds at pH 7 and ∼1.2 folds at pH 9). This study provides a direct comparison of the impacts of sonication and HHP treatment on QPI, which will enable to choose the appropriate processing methods to achieve tailored properties of QPI.

Mackinawite‐Supported Reduction of C1 Substrates into Prebiotically Relevant Precursors

AbstractMackinawite has unique structural properties and reactivities when compared to other iron sulfides. Herein we provide evidence for the mackinawite‐supported reduction of KCN into various reduced compounds under primordial conditions. We proposed a reaction mechanism based on the nucleophilic attack by the deprotonated mackinawite ‐SH surface groups at the carbon atom of HCN. The initial binding of the substrate and the subsequent reduction events are supported by DFT calculations and further experiments using other substrates, such as KSCN, KOCN and CS2. Until now, conversion of CN− into CH4 and NH3 has been limited to nitrogenase cofactors or molecular Fe‐CN complexes. Our study provides evidence for mackinawite‐supported cleavage of the C−N bond under ambient conditions, which opens new avenues for investigation of other substrates for mackinawite‐supported reactions while shedding light on the relevance of this type of reaction to the origin of life on Earth.

Effects of Superheated Steam Treatment on the Allergenicity and Structure of Chicken Egg Ovomucoid.

The aim of this study was to explore the effects of an emerging and efficient heating technology, superheated steam (SS), on the allergenicity and molecular structure of ovomucoid (OVM). OVM was treated with 120–200 °C of SS for 2 to 10 min. The allergenicity (IgG/IgE binding abilities and cell degranulation assay) and molecular structure (main functional groups and amino acids modification) changes were investigated. The IgG-binding ability of OVM decreased and the releases of β-hex and TNF-γ were inhibited after SS treatment, indicating that the protein allergenicity was reduced. Significant increases in oxidation degree, free SH content and surface hydrophobicity were observed in SS-treated OVM. The protein dimer and trimer appeared after SS treatment. Meanwhile, obvious changes occurred in the primary structure. Specifically, serine can be readily modified by obtaining functional groups from other modification sites during SS treatment. Moreover, the natural OVM structure which showed resistance to trypsin digestion was disrupted, leading to increased protein digestibility. In conclusion, SS-induced OVM aggregation, functional groups and amino acids modifications as well as protein structure alteration led to reduced allergenicity and increased digestibility.

SH surface waves in a coated half-space with various types of interfaces

We investigated the propagation of SH surface wave in a coated half-space with imperfect interfaces. By constructing the interface between the surface layer and the half-space with a combination of a spring layer and a thin membrane (in the scope of surface/interface elasticity), we established a combined model for the interface. This combined interface model can degenerate to other interface models by taking the interfacial parameters to various limits. To demonstrate the new findings, we drew dispersion curves of the SH surface waves with the newly established interface models and discussed their dispersion features. The present study completes the whole range influence of the imperfect interfaces on the SH surface waves propagating in coated half-spaces.

Influence of atmospheric-pressure cold plasma-induced oxidation on the structure and functional properties of egg white protein

This study examined the effects of atmospheric-pressure cold plasma (ACP) on the structure and functional properties of egg white protein (EWP). Egg white solution was treated with ACP for 0, 10, 20, 30, and 40 min. The structural unfolding of EWP was confirmed as the exposed free SH group content and surface hydrophobicity increased during the 30 min treatment; however, 40 min of ACP treatment showed the opposite tendency, suggesting the formation of protein aggregates. The emulsion stability of egg white emulsions was the highest at 30 min but decreased again at 40 min. In addition, the proportion of large droplets decreased as the treatment time increased up to 30 min. As a result, moderate oxidation was induced during 30 min of ACP treatment, which could contribute to the enhancement of functional properties of EWP. However, excessive oxidation caused by further ACP treatment negatively affected the enhanced functional properties. Industrial relevanceEgg whites are used as functional ingredients for a variety of food products, so the quality and functionality of egg whites can directly affect the productivity of the final products. The present study suggests the moderate oxidation of egg white protein induced by atmospheric-pressure cold plasma, which could contribute to the enhancement of functional properties. These applied studies can serve as a cornerstone for the establishment of advanced oxidation techniques that can enhance the functionality of egg whites without chemical additives, and consequently contribute to the improvement of food quality and productivity.

Surface/interface effect on the propagation of high-frequency SH surface waves in an ultra-thin FGP over-layer bonded to a substrate

Surface/interface effect on the propagation of high-frequency SH surface waves in an ultra-thin FGP over-layer bonded to a substrate

Patterned superhydrophobic surface fabrication by coupled atmospheric pressure RF and pulsed volume dielectric barrier discharges

AbstractSuperhydrophobic (SH) surfaces have great potential in numerous applications. Plasma polymerization is one of the most efficient technologies for engineering SH surfaces due to its unique feature of tailoring surface chemistry and surface topography simultaneously. Herein, a novel sandwich‐like plasma device that consists of contiguous two‐stage dielectric barrier discharges (DBDs) driven by the time‐modulated radiofrequency (RF) and pulsed power sources is proposed to polymerize hexamethyldisilazane (HMDSN) at atmospheric pressure for the purpose of SH surface engineering. The coordination of dual power sources shows effective performances in plasma operation and material surface treatment, compared to the case driven by any power source alone. Easy ignition and enhanced stability are achievable for the upper RF DBD with the assistance of the bottom pulsed DBD. Vice versa, a diffuser pulsed discharge is obtainable with the input of abundant active and energetic species and precursor fragments from the upper RF plasma. Diagnostic measurements by optical emission spectroscopy and Mie scattering demonstrate that HMDSN fragmentation and nanoparticle nucleation are initiated predominantly by the RF‐driven plasma. These species and nanoparticles are further fragmented and dispersed in the bottom pulsed discharge. Consequently, the desired SH surface is fabricated with a similar pattern to that of the pulsed DBD geometry. This study provides a new pathway based on the plasma‐assisted method to control surface hydrophobicity and provides insights on a new plasma deposition method suitable for atmospheric pressure material processing.

Mercury Adsorption on Thiol-Modified Porous Boron Nitride: A Combined Experimental and Theoretical Investigation

Heavy metal pollutants from industrial wastewater pose a great threat to public health and ecosystem safety. In this paper, a thiol-modified porous boron nitride (pBN–SH) adsorbent synthesized by a facile acid-etching method was studied for the highly selective adsorption of Hg(II) in a complex environment. pBN–SH was characterized by X-ray diffraction, thermogravimetric, elemental analysis, Brunauer–Emmett–Teller analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. The effect of adsorption dosage, pH, contact time, and temperature on Hg(II) adsorption was comprehensively investigated. Characterized results show that thiol groups are loaded on the surface of pBN through oxygen-containing groups and π–π bond. Due to the abundant structural defects and surface modification of functional groups, pBN–SH can effectively capture Hg(II) from water. Compared with the pristine pBN, the adsorption capacity of pBN–SH increases significantly by nearly 2.1 times, which suggests broad application prospects of pBN–SH in removing the Hg(II) aspect. Experimental results corresponding to the pseudo-second-order kinetic, the intra-particle diffusion model, and the Langmuir isotherm demonstrate that pBN–SH holds a high potential in environmental remediation. In addition, the recovered pBN–SH loaded with Hg(II) waste can be available for a valid catalyst for the conversion of phenylacetylene to acetophenone, providing a new way for the reuse of Hg(II)-adsorbed materials. Density functional theory calculations revealed that multitudinous defects and thiol functional groups on the pBN–SH surface, electrostatic attraction, and ligand exchange are responsible for the excellent Hg(II)-selective adsorption capability discovered in the experiment.

Electromagnetoacoustic SH surface waves: Formula for the velocity, existence and uniqueness

The propagation of electromagnetoacoustic SH surface waves (called briefly EMA-SH waves) in non-dispersive piezoelectric media was investigated by Li (1996). Romeo (2004) has derived a formula for the wave velocity. However, it is not valid for all values of material parameters belonging to the existence domain of EMA-SH waves. In this paper, a new formula for the velocity of EMA-SH waves has been derived using the complex function method. This formula is valid for all values of material parameters in the existence domain of EMA-SH waves and more simple than corrected Romeo’s formula. Based on the obtained formula, it is shown that whenever an EMA-SH wave exists, it is unique. We have found the necessary and sufficient condition in an explicit and very simple form for an EMA-SH wave to exist. The correction of Romeo’s formula has been made that makes this formula valid in whole existence domain of EMA-SH waves.

Quantitative analysis of rivulet/ice formation on a heated airfoil by Color-Coded Point Projection method

Ice accumulation on aircraft wings can cause a loss in lift and increased drag. Since the formation of different phenomena like rivulets, water runback, and ice ridges is probable, a better understanding of the underlying physics of these complex phenomena is highly desired. Therefore, having an advanced experimental technique capable of quantifying and characterizing the amount of water or ice will be of high interest. In the present study, a novel Colour-Coded Point Projection (CCPP) method is proposed and used in experiments to investigate the rivulet and ice formation on Al and SH surfaces over a NACA 0012 airfoil with a heated leading edge in the icing wind tunnel. The thickness profiles of rivulets and accreted ice were measured successfully and the effect of heating area on the leading edge and type of the surface were captured. The results showed that the proposed method is a valuable tool for on-line ice/water thickness measurements in an icing wind tunnel.