Showing papers in "Coatings in 2023"
TL;DR: In this paper , the authors proposed and optimized an ultra-wideband solar absorber based on Ti-Al2O3 cross elliptical disk arrays to obtain the ultrawideband absorption of solar energy.
Abstract: Perfect metamaterial absorbers have attracted researchers’ attention in solar energy harvesting and utilization. An ideal solar absorber should provide high absorption, be ultra-wideband, and be insensitive to polarization and incident angles, which brings challenges to research. In this paper, we proposed and optimized an ultra-wideband solar absorber based on Ti-Al2O3 cross elliptical disk arrays to obtain the ultra-wideband absorption of solar energy. The addition of a cavity greatly improves the energy-absorbing effect in the operating band, which has research value. The absorption spectrum and field distribution were analyzed by the finite difference time domain method. For the physical mechanism, the electric and magnetic field distribution indicates that ultra-wideband absorption is caused by propagation surface plasmon resonance (SPR), localized SPR and Fabry–Perot (F-P) resonance excited between Ti and Al2O3 disks. The results demonstrate that the absorption bandwidth with the absorption rate beyond 90% reaches 1380 nm (385–1765 nm), and the average absorption reaches an astonishing 98.78%. The absorption bandwidth matches the main radiation bandwidth of the solar energy, which is approximately 295–2500 nm according to the data from the literature, and the total thickness of the structure is only 445 nm. Moreover, the ultra-wideband solar absorber is insensitive to the polarization angle and oblique incidence angle. The proposed ultra-wideband solar absorber has research and application value in solar energy harvesting, photothermal conversion and utilization.
22 citations
TL;DR: Wang et al. as discussed by the authors proposed a combination of rubber aggregate and permeable concrete, and the mix ratio of rubber permeability concrete mixture material is designed, which is applied to the engineering of pavement in Hunan Province, and its comprehensive pavement performance is analyzed and evaluated.
Abstract: Permeable concrete is a new type of pavement material, which can effectively improve the urban flood discharge system, and is of great significance to the construction of sponge city. In order to optimize the use effect of permeable concrete and improve the application value of permeable concrete in permeable road engineering, the combination of rubber aggregate and permeable concrete is proposed, and the mix ratio of rubber permeable concrete mixture material is designed, which is applied to the engineering of pavement in Hunan Province, and its comprehensive pavement performance is analyzed and evaluated. The results show that the rubber permeable concrete has the best performance when the water cement ratio is 0.3, the designed porosity is 15%, the rubber particle size is 16 mesh, the rubber content is 15% and the coarse aggregate ratio is 4:6. The removal rates of suspended solids and metal pollutants are 0.65 and 0.72, respectively, which are increased by 0.23 and 0.19, respectively, compared with ordinary permeable concrete. This shows that rubber permeable concrete improves the ecological benefits of permeable concrete pavement, gives full play to the economic benefits of waste rubber products, reduces the construction cost of permeable concrete pavement, and provides assistance for promoting the construction of sponge city.
22 citations
TL;DR: In this article , the antifouling performance of the laser clad coatings (LCCs) is investigated by using the water contact angle/surface energy measurement, scanning electron microscope (SEM) surface observation, and phase composition analysis via XRD (X-ray diffractometer) testing.
Abstract: Laser surface treatment is a very useful technology for the fabrication of functional surfaces. In this study, novel antifouling surfaces are fabricated by laser cladding of TC4 and Ni60 mixed materials in various mass ratios on the surfaces of 316L stainless steel substrates. Parametric studies are carried out to investigate the effects of the mixed powder mass ratios and laser cladding parameters on the antifouling performance of the laser clad coatings (LCCs). The antifouling mechanism of the LCCs is investigated by using the water contact angle/surface energy measurement, scanning electron microscope (SEM) surface observation, and phase composition analysis via XRD (X-ray diffractometer) testing. The experimental results show that the LCCs with Ni60/TC4 mass ratio of 3/7 has better antifouling performance in this study. The antifouling performance of the LCC decreases with the increase in laser scanning speed. Surface energy and surface topography have a significant effect on the antifouling performance of LCCs. In order to get the optimal antifouling performance of LCCs, the Ni60/TC4 mass ratio and laser cladding parameters should be optimized.
13 citations
TL;DR: In this article , the impact of symmetry on evaporation triggered top-gathering of micropillars was studied numerically using a COMSOL multiphysics simulation package.
Abstract: High-aspect-ratio (HAR) micropillar arrays offer a wide range of applications in micro-contact printing, switchable transparent optical windows, superhydrophobic surfaces, mechanical sensors, and actuators, due to their properties such as large surface area and excellent mechanical compliance. However, owing to their high aspect ratio, these microstructures are prone to lateral deflection by elastocapillary forces in liquid environments, which is known as top-gathering, limiting their manufacturing processes and applications. Here, the impact of symmetry on evaporation triggered top-gathering of micropillars was studied numerically. The initiation of the micropillar deflection due to capillary forces under varying force distributions was simulated using a COMSOL Multiphysics simulation package. The simulation was carried out for the configurations of two, four, and an array of micropillars. For the four micropillar configuration, a new equation was suggested for calculating the micropillar deflection due to elastocapillary forces, using force distributions around the micropillars. The suggested equation was verified by comparison with the experimental observations. The effect of droplet evaporation on deflection/top-gathering of micropillars was also investigated. It was found that initiation of deflection is due to asymmetry at the rim of the droplet, generating domino-like deflection of the other micropillars. This study provides a new equation/criterion for estimating deflection of the micropillars, suggesting array designs that are resistant to such deflections when interacting with liquids.
7 citations
TL;DR: In this paper , a review examines the methods used to optimize the process parameters of laser cladding, including traditional optimization algorithms such as single-factor, regression analysis, response surface, and Taguchi, as well as intelligent system optimization algorithm such as neural network models, genetic algorithms, support vector machines, the new non-dominance ranking genetic algorithm II, and particle swarm algorithms.
Abstract: This review examines the methods used to optimize the process parameters of laser cladding, including traditional optimization algorithms such as single-factor, regression analysis, response surface, and Taguchi, as well as intelligent system optimization algorithms such as neural network models, genetic algorithms, support vector machines, the new non-dominance ranking genetic algorithm II, and particle swarm algorithms. The advantages and disadvantages of various laser cladding process optimization methods are analyzed and summarized. Finally, the development trend of optimization methods in the field of laser cladding is summarized and predicted. It is believed that the result would serve as a foundation for future studies on the preparation of high-quality laser cladding coatings.
7 citations
TL;DR: In this paper , a structural equation modeling (SEM) approach was used to develop a model involving success factors of superhydrophobic coatings in the oil and gas construction industry of Malaysia.
Abstract: In the oil and gas construction industry, the adoption of superhydrophobic coatings is still in the early adoption phase. Due to the lack of research and the importance of hydrophobic coatings in the oil and gas construction business, this study examined the success determinants of superhydrophobic coatings in Malaysia. This quantitative study included a pilot survey to assess questionnaire validity and Exploratory Factor Analysis (EFA) to reduce success variables discovered through a literature review. A structural equation modeling (SEM) approach was used to develop a model involving success factors of superhydrophobic coatings in the oil and gas construction industry of Malaysia. Four constructs in total were found in SEM, namely, performance success, sustainability construct, oil spill management, and safety and economic success. In total, five items were excluded from the model because their loading factors were less than 0.6. All Cronbach Alpha reliability constants were greater than 0.7, the composite reliability indicators were greater than 0.8, and the AVE was greater than 0.6 for all of the constructs, confirming acceptable reliability and validity statistics. Both convergent and discriminant validity confirmed the relationships between all constructs and the latent variable. The observed path coefficients between the constructs and the latent variable were 0.476 for performance success, 0.461 for sustainability success, 0.322 for oil spill management, and 0.242 for safety and economic success. The significance value for all of the constructs was less than 0.05, confirming the strong relationship between the constructs and the critical success of superhydrophobic coatings in the oil and gas industry.
7 citations
TL;DR: By its nature, plasma spraying is a rapid solidification process in which finely powdered material injected into a plasma jet is almost instantly melted and propelled with high velocity, created by a strong magnetohydrodynamic force against a suitable surface as mentioned in this paper .
Abstract: By its nature, plasma spraying is a rapid solidification process in which finely powdered material injected into a plasma jet is almost instantly melted and propelled with high velocity, created by a strong magnetohydrodynamic force against a suitable surface [...]
5 citations
TL;DR: In this paper , the authors examined the thermodynamic and mass transfer of a Carreau-Yasuda magnetic bionanomaterial with gyrotactic micro-organisms, which is facilitated by radiative peristaltic transport.
Abstract: Nanofluids are considered as an effective way to enhance the thermal conductivity of heat transfer fluids. Additionally, the involvement of micro-organisms makes the liquid more stable, which is important in nanotechnology, bio-nano cooling systems, and bio-microsystems. Therefore, the current investigation focused on the examination of the thermodynamic and mass transfer of a Carreau–Yasuda magnetic bionanomaterial with gyrotactic micro-organisms, which is facilitated by radiative peristaltic transport. A compliant/elastic symmetric channel subject to partial slip constraints was chosen. The features of viscous dissipation and ohmic heating were incorporated into thermal transport. We use the Brownian and thermophoretic movement characteristics of the Buongiorno nanofluid model in this study. A set of nonlinear ordinary differential equations are created from the partial differential equations that control fluid flow. The governing system of differential equations is solved numerically via the shooting technique. The results of pertinent parameters are examined through velocity, temperature, motile micro-organisms, concentration, and heat transfer rate.
5 citations
TL;DR: In this paper , the authors developed models of the stress intensity factor for both edge and center cracks using the extended finite element method, and compared these models to results from the NASGRO method and the optimal mesh sizes for both the crack elements and overall units.
Abstract: The stress intensity factor represents a vital parameter within the realm of linear elastic fracture mechanics. It acts as the cornerstone in determining crack propagation and evaluating damage tolerance. However, calculating this factor is a complex task. To surmount this challenge, models of the stress intensity factor for both edge and center cracks were developed using the extended finite element method. The result of this effort is the ability to calculate the stress intensity factor at the crack tip under different loads and normalized crack lengths. The accuracy of these calculations was confirmed by comparing them to results from the NASGRO method, and the optimal mesh sizes for both the crack elements and overall units were established. Further analysis, conducted through MATLAB’s regression analysis, led to the development of an empirical model. This model was found to be both simple and reliable, making it an ideal tool for engineering applications.
5 citations
TL;DR: In this paper , the authors presented the study results of CrN/TiN multi-layer coatings, as well as single-layer TiN and CrN coatings on Cr12MoV cold work die steel deposited by the vacuum-arc plasma-assisted method.
Abstract: The paper presents the study results of CrN/TiN multi-layer coatings, as well as single-layer TiN and CrN coatings on Cr12MoV cold work die steel deposited by the vacuum-arc plasma-assisted method. Three CrN/TiN coatings of 8-, 16-, and 32-layers were deposited, in which the thickness of each layer was 500 nm, 250 nm and 125 nm, respectively. All of the coatings reveal a face-centered cubic structure with highly oriented (111) growth. The hardness of the CrN/TiN multi-layer coatings was about 27 GPa. Changing the architecture of CrN/TiN multi-layer coatings by reducing the thickness of the CrN and TiN layers from 500 nm to 125 nm promotes a smooth decrease in both the wear parameter and the coefficient of friction. By using an X-ray phase analysis with synchrotron radiation, it was found that 32-layer CrN/TiN coating retained thermal stability during heating in air to a temperature of 1120–1125 °C, and in a vacuum at least to a temperature of 1200 °C.
5 citations
TL;DR: In this article , a review summarizes the theoretical basis of anti-icing behavior and mechanisms, influencing factors of antiicing properties, potential techniques of superhydrophobic surfaces on transmission lines, and, finally, presents future development challenges and prospects of super-hydrophilic surfaces in the antiicing protection of overhead transmission lines.
Abstract: The icing on overhead transmission lines is one of the largest threats to the safe operation of electric power systems. Compared with other security accidents in the electric industry, a sudden ice disaster could cause the most serious losses to electric power grids. Among the numerous de-icing and anti-icing techniques for application, direct current ice-melting and mechanical de-icing schemes require power cuts and other restrictive conditions. Superhydrophobic coating technology has been widely focused for good anti-icing properties, low cost and wide application range. However, the special structure of curved transmission lines, complicated service environments, and variated electric performance could significantly limit the application of superhydrophobic anti-icing coatings on overhead transmission lines. In particular, superhydrophobic surfaces can be achieved by combining the rough micro-nano structure and modification agents with low surface energy. Compared with superhydrophobic coatings, superhydrophobic surfaces will not increase the weight of the substrate and have good durability and stability in maintaining the robust structure to repeatedly resist aging, abrasion, corrosion and corona damages, etc. Therefore, this review summarizes the theoretical basis of anti-icing behavior and mechanisms, influencing factors of anti-icing properties, potential techniques of superhydrophobic surfaces on transmission lines, and, finally, presents future development challenges and prospects of superhydrophobic surfaces in the anti-icing protection of overhead transmission lines.
TL;DR: In this article , the effects of wind speeds, ambient temperatures and salt contents on ice adhesion strength for wind turbine blades were evaluated under various conditions, including wind speed, ambient temperature and salt content.
Abstract: When wind turbines work in a cold and humid environment, especially offshore condition, ice accretion on the blade surfaces has a negative effect on the aerodynamic performance. In order to remove the ice from the wind turbine blade, the adhesive characteristics of atmospheric icing on the blade surface should be mastered under various conditions. The objective of this study is to evaluate the effects of offshore atmospheric conditions, including wind speeds, ambient temperatures and, especially, the salt contents on ice adhesion strength for wind turbine blades. The experiments were conducted on a NACA0018 blade airfoil under conditions including an ambient temperature of −3 °C~−15 °C, wind speed of 6 m/s~15 m/s and salt content of 1~20 mg/m3. The results showed that salt content was the most important factor affecting the ice adhesion strength, followed by ambient temperature and wind speed. The interactive effect of wind speed and salt content, ambient temperature and salt content were extremely significant. The research can provide a reference for the anti-icing for offshore wind turbines.
TL;DR: In this article , the effect of incorporating a mix of reinforcement particles of a hard and soft nature on the microstructure and mechanical and physical properties of a high-strength aluminum alloy, AA7075, was studied.
Abstract: This work studies the effect of incorporating a mix of reinforcement particles of a hard and soft nature on the microstructure and mechanical and physical properties of a high-strength aluminum alloy, AA7075. A friction stir processing technique was used for compositing the surface of this alloy. The vanadium carbide (VC) was selected to be the hard reinforcement, while the boron nitride (BN) and graphene nanoplates (GNPs) were chosen as soft reinforcements. Mono VC, hybrid reinforcements combined of 50 vol.% VC and 50 vol.% BN, and triple reinforcements combined of 33.4 vol.% VC, 33.3 vol.% BN, and 33.3 vol.% GNPs were used for producing the composites. Intensive grain refinement was observed, 930%, in the composite with triple reinforcements. The microhardness and the ultimate compressive strength were improved and reached b0, 29%, respectively, in composites that contained GNPs. The thermal properties were significantly improved, and the coefficients of thermal expansion (CTE) and thermal conductivity decreased to 88% and 15%, respectively. The composite’s electrical conductivity was decreased by 58% with triple reinforcements.
TL;DR: In this paper , the differences in the corrosion properties and protective ability of two bi-layer systems obtained on low-carbon steel in a model corrosive medium of 5% NaCl solution are presented.
Abstract: This study aimed to present the differences in the corrosion properties and protective ability of two bi-layer systems obtained on low-carbon steel in a model corrosive medium of 5% NaCl solution. These newly developed systems consist of Zn-Co (3 wt.%) or Zn-Ni (10 wt.%) alloy coatings as under-layers and a very thin TiO2 sol-gel film as a top-layer. Scanning electron microscopy (SEM) is used for characterization of the surface morphology of the samples indicating that some quantitative differences appear as a result of the different composition of both zinc alloys. Surface topography is investigated by means of atomic force microscopy (AFM), and the hydrophobic properties are studied by contact angle (CA) measurements. These investigations demonstrate that both sample types possess grain nanometric surface morphology and that the contact angle decreases very slightly. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for characterization of the chemical composition and electronic structure of the samples. The roughness Rq of the Zn-Ni/TiO2 is 49.5 nm, while for Zn-Co/TiO2, the Rq value is 53.4 nm. The water contact angels are 93.2 and 95.5 for the Zn-Ni/TiO2 and Zn-Co/TiO2 systems, respectively. These investigations also show that the co-deposition of Zn and Ni forms a coating consisting entirely of Ni2Zn11, while the other alloy contains Zn, Co and the intermetallic compound CoZn13. The corrosion resistance and protective ability are estimated by potentiodynamic polarization (PDP) curves, as well as polarization resistance (Rp) measurements for a prolonged test period (35 days). The results obtained are compared with the corrosion characteristics of ordinary zinc coating with an equal thickness. The experimental data presents the positive influence of the newly developed systems on the enhanced protective properties of low-carbon steel in a test environment causing a localized corrosion—lower corrosion current density of about one magnitude of order (~10−6 A.cm−2 for both systems and ~10−5 A.cm−2 for Zn) and an enhanced protective ability after 35 days (~10,000–17,000 ohms for the systems and ~900 ohms for Zn).
TL;DR: In this paper , an electrochemically assisted deposition of CaP coatings on the titanium alloy, TiAlNb, which is commonly used commercially as an implant material in orthopaedic devices, was examined.
Abstract: Calcium phosphate-based (CaP) bioceramic materials are widely used in the field of bone regeneration, both in orthopaedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The formation of CaP coatings on high-strength implant materials such as titanium alloys combines the superior mechanical properties of metals with the osteoconductive properties of CaP materials. In this work, the electrochemically assisted deposition of CaP coatings on the titanium alloy, TiAlNb, which is commonly used commercially as an implant material in orthopaedic devices, was examined. The barrier properties (electronic properties) of unmodified and CaP-modified titanium alloy were tested in situ in a simulated physiological solution, Hanks’ solution, under in vitro conditions of real implant applications using electrochemical impedance spectroscopy (EIS). The morphology and microstructure of the obtained CaP deposit were characterised by scanning electron microscopy (SEM) and chemical composition was assessed by energy dispersive X-ray spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The aim was to investigate the effect of calcium phosphate CaP coating on the corrosion resistance of the titanium TiAlNb alloy and to understand better the deposition process in the production of bioactive functional coatings on metallic implant materials.
TL;DR: In this article , the authors provide a brief overview of methods for protecting stainless steel from corrosion using a new approach based on superhydrophobization of the surface of stainless steel using laser processing followed by the deposition of a layer of a substance with a low surface energy.
Abstract: Stainless steel has become an integral part of modern engineering materials and daily life due to its mechanical efficiency, strength, recyclability, high resistance to oxidation and corrosive attack, which make it the ideal material for many kinds of applications. At the same time, steel suffers from certain types of corrosion, such as intergranular corrosion, or contact corrosion that develops when stainless steel comes into contact with carbon steel or another metal with a different electrochemical potential. Finally, pitting corrosion is a serious problem often occurring when stainless steel parts work in sea water. This paper provides a brief overview of methods for protecting stainless steel from corrosion using a new approach based on superhydrophobization of the surface of stainless steel using laser processing followed by the deposition of a layer of a substance with a low surface energy. The review discusses the mechanisms of corrosion protection by such coatings and the properties of superhydrophobic coatings presented in the literature. Superhydrophobic protective coatings on stainless steel have been shown to significantly reduce corrosion, with some demonstrating a decrease in corrosion current of up to 156 times. However, a more comprehensive analysis of the mechanisms contributing to this effect, as well as a comparison with anti-corrosion coatings on other metals, suggests that the combination of these mechanisms has the potential to create even more durable and effective surfaces for corrosion protection of stainless steel.
TL;DR: In this article , a detailed description of the materials features, failure mechanism, and failure modeling for both CMC substrate and EBC coatings are presented, and various methods for failure analyses and their pros and cons are discussed.
Abstract: Ceramic matrix composites with environmental barrier coatings (CMC/EBCs) are the most promising material solution for hot section components of aero-engines. It is necessary to access relevant information and knowledge of the physical properties of various CMC and EBCs, the characteristics of defects and damages, and relevant failure mechanisms. Then, effective failure prediction models can be established. Individually assessing the failure of CMC and EBCs is not a simple task. Models considering the synergetic effect of coating properties and substrate fibrous architecture are more reasonable and more challenging. This paper offers a review and a detailed description of the materials features, failure mechanism, and failure modeling for both CMC substrate and EBC coatings. The various methods for failure analyses and their pros and cons are discussed. General remarks on technical development for failure modeling are summarized subsequently.
TL;DR: In this article , Asian plant extracts (APE) and essential oils (EOs) with antioxidant and antimicrobial properties were incorporated into EF for the inhibition of microbial growth in the food matrix.
Abstract: Asian plants (AP) have long been used as natural food preservatives in the food industry. Asian plant extracts (APE) and essential oils (EOs) with antioxidant and antimicrobial properties were incorporated into edible film (EF) for the inhibition of microbial growth in the food matrix. However, information on the utilization of these antibacterial EFs on the storage application of different local food products has not been thoroughly reviewed. Hence, this review gives an overview of the physicochemical, mechanical, antioxidant, and antibacterial properties of EF incorporated with AP and their storage application for the preservation of food products. For their applicability as food packaging, the potency of these EFs to be used as food packaging in preventing food spoilage or foodborne pathogens was also thoroughly reviewed. The addition of APE and EOs into the packaging matrix demonstrated the potential to prolong the storage of food products by preserving food quality (pH, colors, and lipid oxidation) and safety during storage, and the inhibition zones of some extracts against the pathogens demonstrated are weaker in comparison to the standard antibiotic drug used (WHO standards). In conclusion, the freshness of food products could be retained and lengthened by using EF with APE and Eos as active edible food packaging. However, additional research is required to significantly improve its antibacterial activity, producibility, and technical feasibility for long-term market use.
TL;DR: In this paper , the authors evaluated how home bleaching affected the translucency parameter (TP), contrast ratio (CR), total color difference (ΔE), and surface roughness (Ra) of various aesthetic dental ceramics, including innovative ultra-translucent zirconia.
Abstract: The optical qualities of cutting-edge aesthetic dental ceramics are crucial for great aesthetics and may be impacted by various bleaching methods. The objectives of this study were to evaluate how home bleaching affected the translucency parameter (TP), contrast ratio (CR), total color difference (ΔE), and surface roughness (Ra) of various aesthetic dental ceramics, including innovative ultra-translucent zirconia. The three varieties of ceramics that were tested—IPS e.max-Press (IPS); classic zirconia with feldspathic layering (LZr); and translucent zirconia (TZr)—were each represented by seven samples. The samples were bleached at home using 15% carbamide peroxide for six hours a day for seven days. Each specimen’s pre- and post-bleaching CIE L*a*b* values were measured using a spectrophotometer, and the TP, CR, and ΔE were determined. Ra values were measured via 3D profilometry. In comparison to the pre-stage results, statistical analysis showed a significant decrease in TP and increase in CR for LZr and TZr in the post-stage (p < 0.05), but not for IPS (p = 0.398). The results also showed substantial variations in ΔE for the three ceramics (p = 0.020). Ra readings during the post-stage were noticeably greater than those at the pre-stage (p = 0.018). Home bleaching had an impact on the optical characteristics and surface texture of the dental ceramics. Additionally, IPS had greater color stability than LZr and TZr.
TL;DR: A review of the advances in CSAM advances in the last decade, considering new materials, process parameters optimization, post-treatments, and hybrid processing is presented in this article .
Abstract: Cold Spray Additive Manufacturing (CSAM) produces freeform parts by accelerating powder particles at supersonic speed which, impacting against a substrate material, trigger a process to consolidate the CSAM part by bonding mechanisms. The literature has presented scholars’ efforts to improve CSAM materials’ quality, properties, and possibilities of use. This work is a review of the CSAM advances in the last decade, considering new materials, process parameters optimization, post-treatments, and hybrid processing. The literature considered includes articles, books, standards, and patents, which were selected by their relevance to the CSAM theme. In addition, this work contributes to compiling important information from the literature and presents how CSAM has advanced quickly in diverse sectors and applications. Another approach presented is the academic contributions by a bibliometric review, showing the most relevant contributors, authors, institutions, and countries during the last decade for CSAM research. Finally, this work presents a trend for the future of CSAM, its challenges, and barriers to be overcome.
TL;DR: In this article , the most widely used polymer materials are discussed for integrated photonics and four significant sensing applications of polymer-waveguide-based sensors which include biosensing, gas sensing, temperature sensing and mechanical sensing have been debated.
Abstract: In the realization of photonic integrated devices, materials such as polymers are crucial. Polymers have shown compatibility with several patterning techniques, are generally affordable, and may be functionalized to obtain desired optical, electrical, or mechanical characteristics. Polymer waveguides are a viable platform for optical connectivity since they are easily adaptable to on-chip and on-board integration and promise low propagation losses <1 dB/cm. Furthermore, polymer waveguides can be made to be extremely flexible, able to withstand bending, twisting, and even stretching. Optical sensing is an interesting field of research that is gaining popularity in polymer photonics. Due to its huge potential for use in several industries, polymer waveguide-based sensors have attracted a lot of attention. Due to their resilience to electromagnetic fields, optical sensors operate better in difficult situations, such as those found in electrical power generating and conversion facilities. In this review, the most widely used polymer materials are discussed for integrated photonics. Moreover, four significant sensing applications of polymer-waveguide based sensors which include biosensing, gas sensing, temperature sensing and mechanical sensing have been debated.
TL;DR: In this paper , the authors introduce three main types of multi-color LEDs: the organic LED, colloidal quantum dots (CQDs) LED, and CQD-organic hybrid LED.
Abstract: Multi-color light-emitting diodes (LEDs) with various advantages of color tunability, self-luminescence, wide viewing angles, high color contrast, low power consumption, and flexibility provide a wide range of applications including full-color display, augmented reality/virtual reality technology, and wearable healthcare systems. In this review, we introduce three main types of multi-color LEDs: the organic LED, colloidal quantum dots (CQDs) LED, and CQD–organic hybrid LED. Various strategies for realizing multi-color LEDs are discussed including red, green, and blue sub-pixel side-by-side arrangement; vertically stacked LED unit configuration; and stacked emitter layers in a single LED. Finally, according to their status and challenges, we present an outlook of multi-color devices. We hope this review can inspire researchers and make a contribution to the further improvement of multi-color LED technology.
TL;DR: In this article , the surface chemical properties of ZnO NPs coated with three different surfactant biomolecules, namely polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS), were investigated.
Abstract: The uncertainties in ZnO-mediated toxicity and particle stability in a biological system remain a challenge and mitigate against deployment as next-generation nanoparticles (NPs), especially in biomedical applications. With that perspective, the present study investigates the surface chemical properties of ZnO NPs coated with three different surfactant biomolecules, namely polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS) to control the toxicity-induced potentials. On the testing of the surface-functionalized ZnO NPs, notable changes in the particle sizes, morphology, zeta potential, and hydrodynamic size compared to the pure ZnO NPs are observed. In addition, FTIR spectroscopy, TGA, XRD, XPS, and HRTEM analysis showed significant changes in the surface structures and surface functional groups of the three different ZnO NPs on surface functionalization. Following the physical characterization, the cell viability of rat liver BRL-3A-treated ZnO–PEG, ZnO–CTAB, and ZnO–SDS compared to pure ZnO NPs (<50%) falls between 70% and 95% in a dose-determined manner. The cells treated with the pure ZnO NPs showed a higher percentage of apoptotic cells (~61%), which is significantly higher than the 3.4%, 1.5%, and 0.6% for ZnO–PEG-, ZnO–CTAB-, and ZnO–SDS-treated cells (respectively). Furthermore, the surface functionalization was significantly observed to reduce the content of reactive oxygen species (ROS) to 13.6%, 9.7%, and 2.6% compared to the content level of ~71% from the pure ZnO-treated cells. Besides the marked impairment of mitochondrial potentials induced by the pure ZnO NPs, the surfactant–ZnO NPs were observed to slow down the induction of DNA fragmentation and retain the structural integrity of mitochondrial membranes. The toxicity effects are controlled in the order of ZnO–SDS > ZnO–CTAB > ZnO–PEG, i.e., anionic > cationic > non-ionic. Overall from the analysis, the study stresses the importance of having a suitable surface ligand for the ZnO NPs so as to use them in the biomedical sector.
TL;DR: In this paper , the inhibitory effect of Ilex paraguariensis extract on the corrosion of aluminum in 0.1 M HCl solution, in the temperature range of 298-323 K, was studied by using weight loss tests, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS).
Abstract: In the present work, the inhibitory effect of Ilex paraguariensis (Yerba Mate) extract on the corrosion of aluminum in 0.1 M HCl solution, in the temperature range of 298–323 K, was studied by using weight loss tests, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS). The extract of Ilex paraguariensis exhibits improved inhibitory action as its concentration increases while its performance is maintained despite an increase in temperature. EIS theoretical data according to a suitable proposed equivalent circuit were successfully fitted to the experimental data. The adsorption of organic compounds followed a modified Langmuir isotherm behaviour. Derived thermodynamic parameters indicate the occurrence of both chemical and physical adsorption.
TL;DR: In this article , a mixture of mixed-anionic aqueous solutions is used to obtain active powders for bioceramics production in the CaO-SiO2-P2O5-Na2O system.
Abstract: Synthesis from mixed-anionic aqueous solutions is a novel approach to obtain active powders for bioceramics production in the CaO-SiO2-P2O5-Na2O system. In this work, powders were prepared using precipitation from aqueous solutions of the following precursors: Ca(NO3)2 and Na2HPO4 (CaP); Ca(NO3)2 and Na2SiO3 (CaSi); and Ca(NO3)2, Na2HPO4 and Na2SiO3 (CaPSi). Phase composition of the CaP powder included brushite CaHPO4‧2H2O and the CaSi powder included calcium silicate hydrate. Phase composition of the CaPSi powder consisted of the amorphous phase (presumably containing hydrated quasi-amorphous calcium phosphate and calcium silicate phase). All synthesized powders contained NaNO3 as a by-product. The total weight loss after heating up to 1000 °C for the CaP sample—28.3%, for the CaSi sample—38.8% and for the CaPSi sample was 29%. Phase composition of the ceramic samples after the heat treatment at 1000 °C based on the CaP powder contained β-NaCaPO4 and β-Ca2P2O7, the ceramic samples based on the CaSi powder contained α-CaSiO3 and Na2Ca2Si2O7, while the ceramics obtained from the CaPSi powder contained sodium rhenanite β-NaCaPO4, wollastonite α-CaSiO3 and Na3Ca6(PO4)5. The densest ceramic sample was obtained in CaO-SiO2-P2O5-Na2O system at 900 °C from the CaP powder (ρ = 2.53 g/cm3), while the other samples had densities of 0.93 g/cm3 (CaSi) and 1.22 (CaPSi) at the same temperature. The ceramics prepared in this system contain biocompatible and bioresorbable phases, and can be recommended for use in medicine for bone-defect treatment.
TL;DR: In this paper , an experimental test was performed to study the bond behavior between steel rebar and concrete reinforced by polyvinyl alcohol (PVA) fibers, and the results showed that PVA fibers decreased the compressive strength of concrete, but increased splitting tensile, flexural, and direct tensile strength.
Abstract: An experimental test was performed to study the bond behavior between steel rebar and concrete reinforced by polyvinyl alcohol (PVA) fibers. Twenty specimens were prepared and subjected to the pull-out test. Four different fiber volume contents (0%, 0.2%, 0.4%, and 0.6%) were considered and the concrete with the strength grade of C35 was designed in the present study. The effects of PVA fibers, rebar diameter, and cover depth on bond behavior were clarified. The effects of PVA fibers on the mechanical property of concrete were also studied. The results show that PVA fibers decreased the compressive strength of concrete, but increased splitting tensile, flexural, and direct tensile strength. PVA fibers negatively affected bonding in the ascending branch both for the pull-out and the splitting failure cases, but improved the bonding in the descending branch after peak stress for the splitting failure case. In the present test, the maximum decrement of bond strength was about 16.2% for specimens with less than 0.6% PVA fibers. PVA fibers restricted both the macro-cracking and micro-cracking for the splitting cases, the former were much more significant than the latter. The effects of rebar diameter and cover depth on bonding became slight and significant with the increasing content of PVA fibers, respectively.
TL;DR: In this paper , the authors analyzed the variations of a two-fluid electro-osmotic flow of viscoelastic fluid flow through a channel using the Ellis equation.
Abstract: The in vitro fabrication of big osteoarticular implants integrating biomaterials and cells is of tremendous interest because these tissues have a limited ability to regenerate. However, the growth of such cells in vitro is highly problematic, especially later in the culture, when the extracellular matrix has almost filled the initial porous network. Thus, the fluid flow required to properly perfuse the sample cannot be obtained by the hydraulic driving force alone. Fluid pumping is a central concern of a microfluidic system and electro-osmotic pumps (EOPs) are commonly employed for this purpose. Using electro-kinetic equations as a basis, this study analyzed the variations of a two-fluid electro-osmotic flow of viscoelastic fluid flow through a channel. The behavior of the fluid was studied through the Ellis equation. This is how the electro-osmotic pump functions, as demonstrated in the literature that it electrically drags a conducting fluid across a non-conducting fluid through interfacial dragging force along the channel. A steady-state analytical solution for the system in a conducting fluid channel was studied by undertaking an interface planner for fluids exhibiting Newtonian rheological properties. The pumping characteristics were studied in detail by using the Ellis model’s parameters. The fluid rheology was studied, which showed the viability of this technique.
TL;DR: In this paper , the principle of cold spray technology and the deposition mechanism of the composite coatings are introduced, and the effects of key CS process parameters (particle velocity, particle morphology, and substrate state) on the quality of the Cu-based composite coating are summarized.
Abstract: Copper (Cu)-based composite coatings have been widely applied in all kinds of important industry fields due to their outstanding comprehensive properties. The preparation temperature of a composite coating is the key factor affecting the properties, so the cold spray (CS) technology is characterized by low-temperature solid-state deposition, which ensures its emergence as the most promising technology for preparing the Cu-based composite coatings. In this paper, first, the principle of CS technology and the deposition mechanism of the coatings are introduced. On this basis, the deposition mechanism of Cu-based metal/ceramic composite coatings is further explored. Secondly, the effects of key CS process parameters (particle velocity, particle morphology, and substrate state) on the quality of the Cu-based composite coatings are summarized, and the current research status of cold-sprayed Cu-based composite coatings in the fields of corrosion resistance, wear resistance, self-lubricating properties, and electrical conductivity is reviewed. Moreover, the improvement of the performance of Cu-based composite coatings by various post-process treatments of coatings, such as heat treatment (HT) and friction stir processing (FSP), is elaborated. Finally, the future development of Cu-based composite coatings and CS technology is prospected.
TL;DR: In this article , the authors designed a nanocomposite method for the fabrication of MoS2/Co3O4 heterojunction with an extremely productive photocatalytic capability.
Abstract: Photocatalytic hydrogen production joined with simultaneous organic compound removal is a potential but challenging approach for both environmental modification and reusable energy generation. In this study, we designed a nanocomposite method for the fabrication of MoS2/Co3O4 heterojunction with an extremely productive photocatalytic capability. The as-fabricated MoS2/Co3O4 nanocomposites displayed greatly enhanced the hydrogen production (3825 μmol/g/h) and methyl violet dye (MV) contaminant removal (apparent kinetic constant of 0.038 min−1) activity. The nanocomposites’ structures had a better specific surface area, numerous active sites, and enhanced the transport ability of charge carriers to promote the photocatalytic activity. The increase in Co3O4 improved the visible-light absorption efficiency and narrowed energy bandgap and served as a highway for charge carriers to facilitate the transfer and separation and inhibit the combination of photoinduced charge carriers. The migration route of the photoexcited charges, the formation pathway, and the function of various reactive oxygen species (such as O2− and •OH) are discussed. The optimized energy band structure and high electron transfer rate of the S-scheme heterojunction nanocomposite promotes the evolution of H2 and the removal of pollutants, which shows an excellent potential in a stable and efficient photocatalytic hydrogen evolution and environment remediation.
TL;DR: In this paper , a review of the state-of-the-art associated with micro-arc oxidation is carried out, focusing on the influence of aluminium alloys on the appearance of the coating and its characteristics before considering the electrolyte formulation.
Abstract: This review proposes to carry out a state-of-the-art associated with micro-arc oxidation. Firstly, the different aspects of the growth mechanisms of the oxides are detailed. Then, the formation of micro-arcs and the case of soft-spark treatment are discussed. Then, the electrolytic reactions involved in the layer construction are outlined. We focused on the influence of aluminium alloys on the appearance of the coating and its characteristics before considering the electrolyte formulation. We have concentrated some of our efforts on silicate-based electrolytes, mainly used in research and industry. The importance of electrical parameters in layer formation is detailed later. The main factors studied in the literature are the current source, current density, treatment frequency and duration, and duty cycle. We have also noted the different phase compositions identified in the literature. Finally, since the process is particularly advantageous for protecting the surfaces of aluminium parts against wear, we conclude this review by presenting work on the tribological properties of this coating. In this final section, we highlight the work on the wear-reducing properties and tribological mechanisms identified in the literature. Particular attention is paid to the relationship between the nature of the substrates used, the role of the electrolyte and the counterpart choice on the friction and wear results.