Solid Interaction Research Articles

Interaction of Atomic Deuterium with Rutile TiO2(011)-(2×1)

Inspired by the significance of hydrogen–solid interaction in hydrogen energy and catalysis, adsorption, diffusion, and desorption behaviors of deuterium atoms in rutile TiO2(011) have been investigated by temperature-programmed desorption (TPD) and ultraviolet photoelectron spectroscopy (UPS). Upon exposure, a small portion of D atoms adsorb at surface oxygen sites, resulting in the band gap states at 1.35 eV below the Fermi level and desorbing as water at ∼400 K. Most of the D atoms will diffuse into the bulk due to the relatively low activation barrier and the huge capacity of the solid material. These bulk D species desorb as D2/HD between 500 and 800 K. While the desorbing D2O from surface hydroxyls saturates at ∼0.10 monolayer (ML), the yielding D2 is about 96 ML (equivalent coverage) at the largest atomic D exposure of 4.54 langmuir and no saturation trend has been observed in the present work. Detailed analysis indicates the bulk D will diffuse back to the surface and recombine as D2 at elevated temperatures. The differences between the behavior of H(D) in rutile TiO2(110) and TiO2(011) have been discussed by considering the presence of additional bridging oxygen atoms between the in-plane and topmost ones on the latter surface. The striking finding that most surface D atoms diffuse into the bulk of rutile TiO2(011) will not only broaden our understanding of the interaction of H/D with the prototypical metal oxide material but also provide clues to investigate the mechanism of H/D involving reactions over TiO2 catalysts, for example, hydrogen evolution and hydrogenation.

The Study on the Effectiveness of Sustainable Customer Relationship Management: Evidence from the Online Shopping Industry

Sustainable development integrates business, environmental, and social objectives into a unified effort to achieve a common goal. Sustainable customer relationship management (CRM) combines company strategy, customer-focused business processes, and computer technologies. From the consumer’s perspective, it lowers psychological, energy, time, and other costs; from the company’s perspective, it offers a means of engaging with customers to build lasting and reliable relationships. The sustainable CRM program provides advantages to businesses in various industries, particularly online commerce. It alludes to a comprehensive strategy that promotes solid interactions between buyers and sellers of goods and services. Since current customer retention is less costly than new customer attraction in competitive markets, especially online shopping, identifying the factors affecting relationship management with stable customers is essential. This investigation intends to evaluate the effect of the use of management information systems (MIS), as well as insights on employee behavior and knowledge, and customer behavior (satisfaction and loyalty), on the effectiveness of sustainable CRM in online shopping. The model is validated using the PLS–SEM technique, and study sample of 293 employees and managers from private organizations. According to the results, the MIS, employee behavior and knowledge, customer satisfaction, and customer loyalty influence the effectiveness of sustainable CRM in online shopping. Furthermore, employee behavior and knowledge positively moderate the relationship between customer loyalty and the effectiveness of sustainable CRM. However, the moderating role of employee behavior and knowledge on customer satisfaction and the effectiveness of sustainable CRM is not confirmed. Overall, taking these characteristics into account might help organizations to take significant steps toward increasing the efficacy of sustainable CRM.

Effect of heterogeneity size on three-phase contact line formation kinetics

Flotation relies on the differences in surface wettability. Although solids with the same hydrophobicity are generally regarded as having the same capture probability, the heterogeneities found on particle surfaces could complicate bubble–solid interactions. For surfaces with the same hydrophobicity and different sizes of inclusions, the heterogeneity size is expected to affect bubble–solid interactions. In this work, Microelectromechanical system techniques were used to fabricate chemically heterogeneous samples with the same hydrophobicity on which discrete hydrophilic dots with different diameters were distributed. The collision and adhesion processes between free-rising bubbles and these chemically heterogeneous surfaces were studied using a high-speed video camera. For all surfaces, the time intervals between successive collisions and the bubble trajectories were similar before bubble rupture. In contrast, the time elapsed between maximum air bubble deformation and rupture varied, with the rupture time appearing random. Nevertheless, the terminal diameter and average expansion velocity after bubble rupture were negatively correlated with the hydrophilic dot diameter. Thus, for heterogeneous surface with discrete hydrophilic dots, the bouncing behaviour of air bubbles before rupture is independent of heterogeneity size, whereas the three-phase contact line expansion behaviour after rupture is related to heterogeneity size. These insights can provide guiding principles for improving the flotation.

Partial discharge induced decomposition and by-products generation properties of HFO-1234ze(E)/CO2: a new eco-friendly gas insulating medium

HFO-1234ze(E) is introduced as a new eco-friendly insulating gas for medium-voltage gas-insulated equipment (MV-GIE). However, there are few reports on the partial discharge (PD) induced decomposition and gaseous, solid by-product generation characteristics of HFO-1234ze(E)/CO2. Herein, the PD decomposition characteristics of HFO-1234ze(E)/CO2 were explored based on a needle-plate electrode that simulates the metal protrusion defect in MV-GIE. The partial discharge inception voltage, and phase-resolved partial discharge of HFO-1234ze(E)/CO2 under different mixing ratios, PD intensity and duration time at 0.15 MPa were obtained. Meanwhile, the PD-induced decomposition and generation of gaseous, solid by-products of HFO-1234ze(E)/CO2 were analyzed. A three-zone pattern that describes the gas–solid metal interface interaction was proposed for the first time. It is found that the increase of HFO-1234ze(E) content brings superior insulation performance, while the precipitation of gaseous (CF4, C2F6, CHF3, C3HF7) and solid by-products gradually aggravated. In order to avoid the negative impact of PD-induced decomposition on the insulation and service life of MV-GIE, the optimal HFO-1234ze(E) content of 30% is recommended. Based on the optimal mixing ratio (30% HFO-1234ze(E)/70% CO2), the effect of gas pressure and electrode materials on solid precipitation, breakdown voltage was also explored. This work guides the development of HFO-1234ze(E) based MV-GIE and understanding the solid by-products precipitation mechanism of eco-friendly insulating gas.

Joining of Cast Iron and Phosphor Bronze Through Liquid–Solid Interaction: Effect of Ni and Cu Coating on Interfacial Microstructures and Mechanical Properties of Bimetallic Composites

Joining of Cast Iron and Phosphor Bronze Through Liquid–Solid Interaction: Effect of Ni and Cu Coating on Interfacial Microstructures and Mechanical Properties of Bimetallic Composites

The in situ 1 MeV Kr - irradiation study of amorphisation resistance for the Ln2TiO5 (Ln = Lanthanides and Yttrium) Series. A review

The ongoing study of ion – solid interactions is integral for the further development of advanced material technologies servicing semiconductor and nuclear materials. This review focusses on the in situ ion-irradiation, 1 MeV krypton ions, coupled with transmission electron microscopy technique used to characterise the radiation response of Ln2TiO5 (Ln = lanthanides and yttrium) series of ceramic compounds. This series consists of three distinct poly-types; orthorhombic, hexagonal and cubic symmetries, a total of 25 different compounds, allowing radiation response trends within and between structure groups to be investigated. There are three major radiation response characteristics investigated; fundamental damage cascade models, critical fluence of ions required for a crystalline to amorphous transition, and critical temperature for maintaining crystallinity.

Clone particles: A simplified technique to enforce solid boundary conditions in SPH

A simplified technique for the enforcement of boundary conditions along solid profiles is proposed in the framework of the Smoothed Particle Hydrodynamics. The main idea relies on a local definition of the normal and tangent vectors to the solid body, along with a local mirroring of the flow fields. This compound approach allows for a robust and accurate modelling of the fluid–solid interaction close to acute angles and sharp profiles. Numerical benchmarks at increasing complexity are considered to prove the reliability of the proposed technique: hydrostatic test cases, flow past cylinders with elliptic, triangular and spiked circular profile and, finally, a roto-translating motion of a spiked cylinder. The results are compared and validated with other numerical methods.

Modelling of Catalytic Combustion in a Deformable Porous Burner Using a Fluid–Solid Interaction (FSI) Framework

The various concepts involved in the mathematical modeling of the fluid-solid interactions (FSIs) of catalytic combustion processes occurring within a porous burner are presented and discussed in this paper. The following aspects of them are addressed: (a) the relevant physical and chemical phenomena appearing at the interface between the gas and the catalytic surface; (b) a comparison of mathematical models; (c) a proposal of a hybrid two/three-field model, (d) an estimation of the interphase transfer coefficients; (e) a discussion of the proper constitutive equations and the closure relations; and (f) a generalization of the Terzaghi concept of stresses. Selected examples of application of the models are then presented and described. Finally, a numerical verification example is presented and discussed to demonstrate the application of the proposed model.

Dissimilar cavitation dynamics and damage patterns produced by parallel fiber alignment to the stone surface in holmium:yttrium aluminum garnet laser lithotripsy.

Recent studies indicate that cavitation may play a vital role in laser lithotripsy. However, the underlying bubble dynamics and associated damage mechanisms are largely unknown. In this study, we use ultra-high-speed shadowgraph imaging, hydrophone measurements, three-dimensional passive cavitation mapping (3D-PCM), and phantom test to investigate the transient dynamics of vapor bubbles induced by a holmium:yttrium aluminum garnet laser and their correlation with solid damage. We vary the standoff distance (SD) between the fiber tip and solid boundary under parallel fiber alignment and observe several distinctive features in bubble dynamics. First, long pulsed laser irradiation and solid boundary interaction create an elongated "pear-shaped" bubble that collapses asymmetrically and forms multiple jets in sequence. Second, unlike nanosecond laser-induced cavitation bubbles, jet impact on solid boundary generates negligible pressure transients and causes no direct damage. A non-circular toroidal bubble forms, particularly following the primary and secondary bubble collapses at SD = 1.0 and 3.0 mm, respectively. We observe three intensified bubble collapses with strong shock wave emissions: the intensified bubble collapse by shock wave, the ensuing reflected shock wave from the solid boundary, and self-intensified collapse of an inverted "triangle-shaped" or "horseshoe-shaped" bubble. Third, high-speed shadowgraph imaging and 3D-PCM confirm that the shock origins from the distinctive bubble collapse form either two discrete spots or a "smiling-face" shape. The spatial collapse pattern is consistent with the similar BegoStone surface damage, suggesting that the shockwave emissions during the intensified asymmetric collapse of the pear-shaped bubble are decisive for the solid damage.

Bio-inspired water-driven electricity generators: From fundamental mechanisms to practical applications

Harvesting water energy in various forms of water motion, such as evaporation, raindrops, river flows, ocean waves, and other, is promising to relieve the global energy crisis and reach the aim of carbon neutrality. However, this highly decentralized and distributed water energy poses a challenge on conventional electromagnetic hydropower technologies that feature centralization and scalization. Recently, this problem has been gradually addressed by the emergence of a myriad of electricity generators that take inspiration from natural living organisms, which have the capability to efficiently process and manage water and energy for survival in the natural competition. Imitating the liquid–solid behaviors manifested in ubiquitous biological processes, these generators allow for the efficient energy conversion from water–solid interaction into the charge transfer or electrical output under natural driving, such as gravity and solar power. However, in spite of the rapid development of the field, a fundamental understanding of these generators and their ability to bridge the gap between the fundamentals and the practical applications remains elusive. In this review, we first introduce the latest progress in the fundamental understanding in bio-inspired electricity generators that allow for efficient harvesting water energy in various forms, ranging from water evaporation, droplet to wave or flow, and then summarize the development of the engineering design of the various bio-inspired electricity generator in the practical applications, including self-powered sensor and wearable electronics. Finally, the prospects and urgent problems, such as how to achieve large-scale electricity generation, are presented.

Effect of Packing Structure Evolution on the Flow Characteristics in a Binary Composite Packed Bed Based on DEM-CFD Method

The evolution of mesoscale structures of particle packing in binary composite packed beds and their effects on flow characteristics and wall effects were investigated using the discrete element method (DEM) and computational fluid dynamics (CFD). The DEM model was used to build a series of randomly mixed packing structures of particles in accordance with the dynamic change of mass ratio between particles in two size ranges, which were then confirmed by the findings of an X-ray tomography (CT) scan. The results show that the packing structure of b25s75 was conducive to reducing the influence of wall effect in packed bed reactors. For b25s75, the dimensionless distance of radial porosity fluctuation from the wall is 0.3705, which is the smallest among the five packing models, indicating that this structure plays a suppressive role on the wall effect. In addition, the uniformity of velocity and temperature distributions in both the radial and axial directions of different packing structures were compared. The standard deviations of radial relative velocity distributions in the packed beds of b100, b75s25, b25s75 and s100 are 0.28, 0.178, 0.139 and 0.156, respectively, indicating that the stacking mode of b25s75 can make the fluid flow and the gas–solid interactions more uniform.

The Effect of Liquid–Solid Interactions upon Nucleate Boiling on Rough Surfaces: Insights from Molecular Dynamics

Despite the fact that engineered surface enabling remarkable phase change heat transfer have elicited increasing attention due to their ubiquitous applications in thermal management, the underlying mechanisms of intrinsic rough structures as well as the surface wettability on bubble dynamics remain to be explored. Therefore, a modified molecular dynamics simulation of nanoscale boiling was conducted in the present work to investigate bubble nucleation on rough nanostructured substrates with different liquid-solid interactions. Specifically, the initial stage of nucleate boiling was mainly investigated and the bubble dynamic behaviors were quantitively studied under different energy coefficients. Results shows that as the contact angle decreases, the nucleation rate increases, because liquid obtains more thermal energy there compared with that on less wetting surfaces. The rough profiles of the substrate can provide nanogrooves, which can enhance initial nucleate embryos, thereby improving thermal energy transfer efficiency. Moreover, atomic energies are calculated and adopted to explain how bubble nuclei are formed on various wetting substrates. The simulation results are expected to provide guidance towards surface design in state-of-the art thermal management systems, such as the surface wettability and the nanoscale surface patterns.

Combustion‐enabled underwater vehicles (CUVs) in dynamic fluid environment

AbstractUnderwater vehicles have opened a unique path to multifunctionality and environmental adaptability. However, inadequate studies have been conducted to investigate the dynamic principle and performance of underwater vehicles in real applications with complex external conditions. Here, we propose a type of combustion‐enabled underwater vehicles that can perform stable high‐speed motions under dynamic fluid environment. Experiments are conducted to test the kinematic performance. Numerical simulations are developed to investigate the fluid–solid interaction phenomenon, and theoretical modeling is derived to study the dynamic principle of the combustion actuation process. The experimental, numerical, and theoretical results are compared with satisfactory agreements. The underwater vehicles perform ~3.4 body‐length distance within 0.2 s and a maximum speed of ~30 body‐length per second in horizontal direction. Parametric studies are conducted to investigate the sensitivity of the key factors to the kinematic performance of the reported underwater vehicles. In the end, we report the hybrid combustion‐enabled underwater vehicles (CUVs) that combined with propeller to realize continuous driving for multi‐mode operations. The experimental, numerical, and theoretical results indicate that hybrid CUVs can achieve more flexible and controllable motion performance.

Tracing spatial confinement in semiconductor quantum dots by high-order harmonic generation

We report here on results of systematic experimental-theoretical investigation of high-order harmonic generation (HHG) in layers of CdSe semiconductor quantum dots of different sizes and a reference bulk CdSe thin film. We observe a strong decrease in the efficiency, up to complete suppression of HHG with energies of quanta above the band gap for the smallest dots, whereas the intensity of below band gap harmonics remains weakly affected by the dot size. In addition, it is observed that the suppression of the above gap harmonics is enhanced with increasing the driving wavelength. These systematic investigations allow us to develop a simple physical picture explaining the observed suppression of the highest harmonics: the discretization of electronic energy levels seems to be not the predominant contribution to the observed suppression but rather the confined dot size itself, causing field-driven electrons to scatter off the dot's walls. The reduction in the dot size below the classical electron oscillatory radius and the corresponding scattering limits the maximum acceleration by the laser field. Moreover, this scattering leads to a chaotization of motion, causing dephasing and a loss of coherence, therefore suppressing the efficiency of the emission of highest-order harmonics. Our results demonstrate a regime of intense laser-nanoscale solid interaction, intermediate between the bulk and single-molecule response, and are crucial for nanophotonic platforms aiming at control over high-order harmonic properties and efficiency.

Adsorption of chalcogenide gas by 2H-MoSe2 monolayer modified by transition metal

Nowadays, detecting the more hazardous sulphur group of gases (H2S, SO2) is increasingly essential, and there is a need to find a readily fabricated, low-cost, high-performance 2D material. This study investigated the selective detection of H2S and SO2 by MoSe2 monolayers and Pt-doped MoSe2 monolayers using first-principles calculations. Our results show that the dopant dramatically enhances the activity of the material, creating solid interactions with the material surface and that Pt-doped MoSe2 monolayers have the potential to selectively detect these toxic gases because of their different conductive tendencies. This work provides insights into the potential application of unexplored TMDs as chemically resistant sensors for the detection of poisonous gases, which may be of importance for environmental monitoring and industrial manufacturing.

Characterization of oil-in-water microemulsions based on ethoxylated surfactant for paraffinic deposits removal

Paraffin deposition is still a challenge in the oil industry and could be extremely costly until reaching the production stop. Microemulsions are surfactant-based systems able to prevent or remediate paraffin deposition. This work reports the characterization of an oil-in-water (O/W) microemulsion system (ME) with the potential for removing paraffinic deposits. The systems were characterized regarding phase equilibrium, droplet size, and rheology for three different phase oil components: kerosene, xylene, and Diesel. Moreover, fluid–solid interaction experiments were performed in order to evaluate the capacity of solubilization and understand how the rheological behavior is modified after paraffin solubilization. The O/W microemulsion prepared under different compositions tends to form Winsor-IV with particle size varying from 2.9 up to 56.7 nm. Wettability between the paraffin and microemulsion tends to increase with time, being completely spread for some of the systems obtained. A content of 5 % wt. of paraffin on the microemulsion system does not alter the phase equilibrium and the rheology behavior. We observe a slight alteration in the absolute viscosity values, between 10 and 60 °C, but not affecting flow assurance conditions.

Mathematical problems of dynamical interaction of fluids and multiferroic solids

In the paper, we consider a three-dimensional mathematical problem of fluid-solid dynamical interaction, when an anisotropic elastic body occupying a bounded region is immersed in an inviscid fluid occupying an unbounded domain . In the solid region, we consider the generalized Green–Lindsay's model of the thermo-electro-magneto-elasticity theory. In this case, in the domain we have a six-dimensional thermo-electro-magneto-elastic field (the displacement vector with three components, electric potential, magnetic potential, and temperature distribution function), while we have a scalar acoustic pressure field in the unbounded domain . The physical kinematic and dynamical relations are described mathematically by the appropriate initial and boundary-transmission conditions. Using the Laplace transform, the dynamical interaction problem is reduced to the corresponding boundary-transmission problem for elliptic pseudo-oscillation equations containing a complex parameter τ. We derive the appropriate norm estimates with respect to the complex parameter τ and construct the solution of the original dynamical problem by the inverse Laplace transform. As a result, we prove the uniqueness, existence, and regularity theorems for the dynamical interaction problem. Actually, the present investigation is a continuation of the paper [Chkadua G, Natroshvili D. Mathematical aspects of fluid-multiferroic solid interaction problems. Math Meth Appl Sci. 2021;44(12):9727–9745], where the fluid-solid interaction problems for elliptic pseudo-oscillation equations associated with the above mentioned generalized thermo-electro-magneto-elasticity theory are studied by the potential method and the theory of pseudodifferential equations.

Detection of Energetic Ions Based on Tapered Optical Fiber

Single-mode tapered optical fibers (TOF) are well-known for applications in sensing. In this work, we demonstrate the use of tapered optical fibers to detect charged particles (ions) irradiated at various energies, fluences, and species. In this experiment, two different ion species, namely, Ar+ and N+, have been used to irradiate tapered optical fibers at various fluences and energies. The variations in the free spectral range (FSR), period, and transmission power loss from the ion beam irradiated TOFs are picked up by the optical spectrum analyzer (OSA). We were able to identify ions with energy as low as 80 keV because of the change in the refractive index of the cladding material caused by the implanted ions. The observed changes in spectra are explained using the results of COMSOL simulations. Using Monte Carlo-based TRI3DYN ion–solid interaction simulation, the surface modification and defect formation caused by ion beams as well as the implantation profile in the TOF have been predicted. These results are further corroborated by experimental studies such as scanning electron microscopy and Raman scattering spectroscopy. Such a tapered optical fiber-based detection method will aid in the creation of portable equipment to identify charged particles in nuclear reactors and in space exploration.

Black Phosphorus Nanosheets Decorated Multiscale Zinc Ferrite Spheres Toward Swift and Humidity-Tolerant Breath Acetone Sensing

Unreasonable acetone emission from various cosmetic and industrial products readily imposes severe ecological harm and human health through airborne transmission and groundwater circulation, thus necessitating the pressing requirement of sensitive and swift acetone detection. To this end, chemoresistive MEMS acetone sensors featuring the sensing layer of a few black phosphorus (BP) nanosheets-modified multiscale zinc ferrite (ZnFe2O4) spheres were leveraged in this work. After the optimization of constituent combination and operation temperature, the 0.5 wt% BP/ZnFe2O4 sensors could recognize 0.1–2 ppm acetone at 188 °C. With respect to pure ZnFe2O4 analog, the 0.5 wt% BP/ZnFe2O4 sensors delivered approximately twofold response enhancement (5.34 versus 2.73 toward 0.5-ppm acetone) and stronger sensitivity (5/ppm versus 3/ppm). Also, excellent selectivity, repeatability, and long-term stability were exhibited. The response/recovery times of 6/63 s toward 0.5-ppm acetone manifested a swift balance of gas–solid interaction. Inspiringly, the sensor showed an excellent humidity-resistant response toward 100-ppb acetone. Moreover, the simulated detection revealed a high application potential in diabetic monitoring featuring sub-ppm acetone and a high moisture environment. The ameliorated sensor performance after incorporating few but modest BP could be attributed to the consequent larger specific surface area, richer oxygen vacancies, and numerous p-n heterojunctions.

Comparative studies on performance of plain, perforated, threaded, and threaded–perforated pin fin: A numerical approach

AbstractA heat sink is a thermal management system for electrical and electronic appliances whose performance is a function of fin geometry, arrangement, and flow field. Earlier research addressed the enhancement in the heat dissipation capacity of the sink with a change in the geometry of the fin. However, the change should increase the heat transfer rate per unit weight and per unit volume. One such attempt is made in the present work, which deals with numerical forced convection heat transfer simulation over a pin fin with three different surface modifications, namely, threads, equilateral triangular perforation, and threads with perforations. A numerical investigation is performed for 0.5773–2.5574 mm pitch of threads, 3–4.8 mm size of perforation, and 2–8 m/s velocities of air. To describe the flow pattern around the fin and its variation with surface modification, streamline profiles are drawn which reveals that the fluid–solid interaction is improved either with threaded or perforated surface and is maximum for threaded–perforated fin. The enhanced convection rates bring down the local fin temperature and the maximum fin temperature, where the drop is more for the threaded surface than that of the perforated surface because of turbulence. A 10° drop in maximum fin temperature is achieved by replacing a plain pin fin with a threaded–perforated pin fin, and the drop is 8° with threads alone and 6° only with perforations. The increased fineness of threads and size of perforation further bring down the maximum fin temperature.