Sprayed Layer Research Articles

Experimental Study of Erosion Prevention Model by Bio-Cement Sand

Microbially induced carbonate precipitation (MICP) technology is employed to reinforce the surface soil of a dam, aiming to prevent erosion caused by water flow and damage to the dam slope. The relationship between penetration depth, calcium carbonate content, and bonding depth was investigated at eight measuring points on the sand slope surface of a mold under different reinforcement durations. It was observed that as grouting reinforcement times increased, there was a gradual increase in calcium carbonate content but a rapid rise in penetration resistance. Moreover, the bonding depth of sand on the bio-reinforced sand slope increased with higher levels of calcium carbonate content. Microbial grouting reinforcement enhanced soil particle bonding force, requiring water flow to overcome this force for activation of sand particles. Consequently, microbial grouting reinforcement significantly improved shear strength and critical starting flow velocity on sand slope surfaces. The experimental results demonstrated that after MICP surface treatment through spraying, a dense and water-stable hard shell layer composed of bonded calcium carbonate and soil particles formed continuously on sample surfaces, effectively enhancing the strength and erosion resistance of sandy soils. These findings provide reliable evidence for silt slope reinforcement and dam erosion prevention.

Layer formation, morphology and photoluminescent properties of ultrasonic spray of pre-formed YVO4:Eu and SiO2 coated ZnS:Mn nanoparticles

In this work, we study the coating process and coating quality of photoluminescent particles deposited on a glass surface in terms of particle distribution and associated film continuity. The dispersion process of commercial ZnS:Mn particles and YVO4:Eu particles synthesized by microwave reactor in aqueous solutions onto solid surface was performed using an ultrasonic atomizer. Two methods of particle deposition were used, one by moving the substrates while spraying and in the second the substrates were not moved. The measured zeta potential values of 42.9 mV and 45.3 mV, respectively, show that the dispersion of YVO4:Eu nanoparticles, in water, is stable at concentrations of 1.2 wt% and 2.4 wt% without the addition of capping agents. It was also found that the dispersion area increases as the flow rate increases from 1 ml/min to 3 ml/min at constant suspension concentration and spraying time. To stabilize the ZnS:Mn particles in solution, either surfactants or a silica capping layer prepared by a sol-gel process were used.The dispersion area encompassing the major amount of dispersed particles was evaluated, The SEM images demonstrate the effectiveness of the ultrasonic atomizer spraying procedure in the disaggregation nanoparticles, as seen by the reduced mean particle size in the sprayed layer compared to the as prepared powder. Finally, this study suggest that the dispersion process of photoluminescent nanoparticles on a substrate holds the potential for optical traceability.

Структурные особенности и трибологические свойства многослойных высокотемпературных плазменных покрытий

Introduction. Multilayer high-temperature coatings obtained using plasma spraying, are studied. The combination of layers of different chemical and phase compositions made it possible to increase wear resistance by 1.5–2.0 times. The purpose of this work is to study the influence of the chemical composition of sprayed coatings on the phase composition, structure, micromechanical and tribological characteristics under conditions of dry sliding friction of surface layers. Materials and methods of research. Coatings A and B consist of sequentially sprayed layers. The first and second layers were sprayed in a reducing atmosphere: the first layer was a heat-resistant self-fluxing powder of two systems: 1 – Fe-Cr-Si-Mn-B-C for coating A and 2 – Fe-Ni-Si-Mn-B-C for coating B; the second layer was a mixture of self-fluxing powder with iron powder in a 1:1 ratio. The third layer was obtained by spraying iron powder in an oxidizing atmosphere to form a metal oxide coating. To create a layer of scale on the surface, coated specimens were subjected to high-temperature annealing at a temperature of 1,000 ℃. The chemical composition and nature of the distribution of elements over the thickness of the coatings were determined by micro-X-ray spectral analysis using a TWSCAN scanning electron microscope with an Oxford energy-dispersive attachment. Microhardness and micromechanical properties were studied using an instrumental microhardness tester of the Fischerscope HM2000 XYm system at a load of 0.980 N. Determination of tribological properties was carried out on a laboratory installation using the “finger-disc” scheme at loads of 30, 75, 100 and 130 N. To measure roughness parameters and obtain 3-D profilometry of surfaces after testing, a non-contact profilometer-profiler Optical profiling system Veeco WYKO NT 1100 was used. Results and discussion. Metallographic studies have shown that the formed multilayer coatings consist of an internal metal layer and an external oxide layer with a total thickness of the entire coating up to 800–850 μm. It is established that the first sprayed layer has the highest level of microhardness, which is due to the high-volume fraction of the strengthening phases contained in it (~ 95 %). It is shown that the coating A has increased wear resistance, which is expressed by minimal weight loss (~ 1.5 times less than that of the coating of the coatimg B), the friction coefficient was f = 0.3 for coating A and f = 0.4 for coating B. The study of wear surfaces has shown that for all selected test loads under sliding friction conditions, the coating of both compositions was preserved, even at a maximum load of 130 N.

Deposition mechanism and fracture characterization of 434 stainless steel HOVF coating on T6061 aluminum alloy

434 stainless steel coatings have been applied T6061 alloy using High-Velocity Oxygen Fuel (HVOF) as a deposition technique for surface performance improvement. The relationship between the coating's deposition characteristics of thickness, homogeneity, porosity, and hardness and the spraying parameters of mainly the number of sprayed-layers and spraying distance was revealed. The coating's fracture behaviors was further studied using three-point bending and digital image correlation (DIC) technology, which allows the observation of the crack progression and record the stress distribution on the coatings. Results showed that the crack progression always occur at the oxides between the different sprayed layers or surrounding semi-melted feedstock particles, the crack progression mode is mainly depending on the number and location of oxides in the coating. Then, the crack progression mainly continued through the interface between sprayed layers while the oxide content approach or exceed a critical value of 12 %. Finally, a model for the coating fracture mechanism was established to explain the interface bonding performance between the coating and the substrate.

Elaboration of spinel Co3O4 via cost-effective chemical spray pyrolysis for enhanced photo-response

Co3O4 thin layers were produced through spray pyrolysis, varying the spray duration from 10 to 25 minutes. Various characterizations were employed to explore the impact of spray durations on the sprayed layers properties. They exhibited a cubic structure with strong preferred orientation along the (111) direction. Morphological analysis indicated a good morphology as the duration increased. Compositional analysis confirmed the predominant presence of Co and O in the growing layer. Optical properties revealed an augmentation in absorption with prolonged duration. The band-gap energy decreased from 1.45 to 1.40 eV for durations from 10 to 20 minutes. The optical and electrical properties were influenced by duration. Notably, Co3O4 (20 minutes) exhibited a significant variation in resistance between light ON and OFF. These findings highlight the ability to tailor the properties of Co3O4 compound by optimizing the spray duration for the effective fabrication of photo-sensors.

Debonding of Porous Coating: A Late Failure Mode of Uncemented, Partially Threaded Acetabular Components—Retrieval Analysis

Titanium plasma-sprayed (TPS) porous coatings have been used in total hip arthroplasty for decades. They are considered reliable, and very few failure cases have been described so far. This retrieval study described a series of 20 acetabular components—where total or partial debonding occurred during in vivo use and aimed to explain the underlying failure mechanisms. Implants were examined using optical and electron microscopy (SEM), metallographic sections of retrievals were prepared while pathologic samples of periprosthetic tissues were examined for presence of wear debris. Data from metallographic slides indicated that debonding was initiated at free borders of the coating and tended to progress at the interface between the TPS layer and the shell. In some cases, total debonding occurred leading material wear of both the TPS layer and acetabular shell leading to massive release of metallic debris and accelerated polyethylene wear in third body mechanism. SEM examination demonstrated that splats forming the TPS layer exhibited features suggesting a high temperature gradient between the plasma sprayed layer and the substrate material existed, leading to porosity of splats and suboptimal bonding strength. This study demonstrated that coating application parameters and certain design features (screw holes, fins) may promote long-term failure due to debonding. Surgeons should be aware of this complication as it is most likely underreported, while manufacturers should consider more rigorous pre-clinical testing as suboptimal coating bonding may result in failures during long-term clinical use.

MATERIALS FOR IMPREGNATION OF POROUS METALLIZATION THERMAL SPRAYED ANTICORROSIVE COATINGS OF SUBMERSIBLE OILFIELD EQUIPMENT. Part 2

The use of thermal sprayed coatings in aggressive petroleum fluid is limited due to the presence of porosity in it. When fluid gets into the pores, corrosion processes begin and thereby reduce the protective properties of thermal sprayed coating. The application of impregnating compounds makes it possible to seal open porosity and prevent the penetration of aggressive environments into the metal under the coating, thereby increasing the barrier properties of the coating. Epoxy polymer materials demonstrate high corrosion resistance and are widely used in the oil industry to protect pipeline elements and submersible oilfield equipment during operation. The second part of the article presents both traditional polymer impregnation materials and new compositions with magnetic nanoparticles and nanocarbon fillers (fullerenes, graphene and nanotubes) which, due to the created magnetic field, are evenly distributed throughout the polymer matrix and increase the crack resistance of the matrix. Polymer impregnating materials of both domestic and foreign production based on phenolic, epoxy, acrylic and urethane resins, modes of their application, conditions of their operation and temperature restrictions are considered. The possibility of using existing independent anti-corrosion polymer coatings as an impregnation of metallization thermal sprayed layers is discussed. Their advantages and disadvantages are highlighted. Examples of self-healing polymer matrices are given that are capable of recognizing the onset of corrosion processes and responding by releasing appropriate effective self-healing agents. The possibility of adding inhibitors to the polymer matrix is described, which helps to increase the anti-corrosion properties of the coating and thereby increase the time between failures of equipment. The issue of normative regulation of the use of impregnating compositions in various fields of industry is covered. The main directions of research that need to be carried out to solve the problem of using polymer materials as the most promising impregnating compositions for anti-corrosion thermal sprayed coatings of submersible oilfield equipment have been identified. First of all, it is necessary to reduce the viscosity of polymer resins to increase their penetration into open pores.

Study on Microstructure and Wear Resistance of WC-based Cermet Coatings Prepared by HVAF

Abstract To mitigate the risk of vapor corrosion damage to the overflow mechanical parts, WC-based metal-ceramic coatings were applied to the surface of a 45-gauge steel substrate by supersonic air-assisted flame spraying (HVAF). The mechanical and wear-resistant qualities of the coating were identified by Vickers micro-hardness, ball-disc friction, and wear test, as well as optics, scanning electron, X-ray diffractometer, and white light interferometer systems. The findings demonstrate the layered structure of the WC-based coating, which is made up of the bonded phase and its distribution of hard phase particles that are diffusely dispersed. The coating is free of cracks, inclusions, and other defects, and its structure and organization are dense with a porosity of 0.86 ± 0.05%. The phenomenon of oxidative decarburization did not occur in the process of preparing the WC hard phase for WC-based metal-ceramic coatings. As a result, the coating’s micro-hardness of 11.83 ± 0.55 GPa is eight times that of the substrate. The results of comparing the three-dimensional abrasion patterns of the coating and the substrate reveal that the coating has superior abrasion resistance because its width and depth of abrasion are smaller than that of the substrate and a lot of furrows have formed on the substrate material’s surface. In contrast, the sprayed layer only had faint traces of abrasion. After three years of actual service, the impeller surface coating is essentially unaltered, which effectively addresses the issue of vapor corrosion damage to the slurry pump’s impeller and extends the pump’s service life to guarantee the overflow mechanical components operate safely and steadily.

Corrosion behavior of austenitic stainless steel and nickel-based welded joints in underwater wet welding

Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103 m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.

CFD investigation of post-combustion CO2 capture using an industrial spray tower: Regulation effects of spray schemes

The use of spray towers for post-combustion CO2 capture has attracted growing industrial interest. However, its practical application is hampered by a lack of knowledge about CO2 spray absorption on an industrial scale. Herein, we developed a numerical model to explore the potential of the spray tower for CO2 removal at a 330 MW coal-fired power plant. The model was developed in the Euler-Lagrange framework integrated with interphase transfer models. The variations of gas-droplet flow, CO2 removal efficiency, CO2 loading of rich solution, and temperature distribution under different spray schemes were investigated. It was found that gas flow hydrodynamics and CO2 removal performance can be regulated by the spray scheme. Compared to the conventional downward spray scheme, the lower nozzle layer adopted an upward spray scheme can improve the uniformity of the gas flow and results in several advantages: (1) average droplet residence time is extended by 5.2 %; (2) CO2 removal efficiency increases from 79.1 % to 82.9 %. This improvement is attributed to two factors: one is the droplet’s re-distribution, lowering the gas flow resistance in the region below the first spray layer near the inlet; the other is the change in gas-droplet interaction whereby the upward-moving droplets entrain the gas to flow upwards. Moreover, we investigated the effects of the spray schemes under varying flue gas loads. Under these conditions, the upward spray mode adopted in the first layer shows the best CO2 removal performance. Further theoretical analysis reveals the mechanisms underlying the regulation effect. The findings in this work will benefit the design and optimization of the industrial-scale spray tower for CO2 removal.

Study of the Effectiveness of Corrosion Resistance Growth by Application of Layered AlN–TiO2 Coatings

The work is devoted to the study of the use of AlN–TiO2 coatings as protective materials against corrosion and natural aging, as well as a rise in wear resistance of the steel surface under long-term mechanical influences. The choice of oxy-nitride coatings obtained by magnetron sputtering by layer-by-layer deposition of layers of aluminum nitride and titanium oxide with layer thicknesses of the order of 50 nm and 100 nm as objects of study is due to their high resistance to external influences, which can have a significant impact on growth in the resistance to degradation processes associated with hydrogenation during the operation of steel structures. During determination of the hydrophobicity/hydrophilicity of AlN–TiO2 coatings, it was found that the applied coatings, regardless of the conditions for their preparation, have hydrophobic properties (the contact angle is ~125–130°), which are preserved both during corrosion tests (except for TiO2 coatings, for which the change in the contact angle after corrosion tests is ∆ ~ 10°) and when modeling natural aging processes. During the tribological tests of coating samples, it was found that a growth in the number of spray layers (when alternating them) leads to a rise in wear resistance, both in the case of the initial samples and for samples subjected to corrosion in a model solution of 0.1 M NaCl and when simulating natural aging processes.

Method of 3D Coating Accumulation Modeling Based on Inclined Spraying.

In the process of repairing the surface of products in aviation, aerospace, and other fields by spraying, accurate 3D cumulative-coating modeling is an important research issue in spraying-process simulation. The approach to this issue is a 3D cumulative-coating model based on inclined spraying. Firstly, an oblique spraying layer cumulative model was established, which could quickly collect the coating thickness distribution data of different spray distances. Secondly, 3D cumulative-coating modeling was conducted with the distance between the measuring point and the axis of the spray gun and the spraying distance between the measuring points as the input parameters, and the coating thickness of the measuring point as the output parameter. The experimental results show that the mean relative error of the cumulative model of the oblique spraying layer is less than 4.1% in the case of a 170~290 mm spraying distance and that the model is applicable in the range of -80~80 mm, indicating that the data on the oblique spraying coating proposed in this paper is accurate and fast. The accuracy of the 3D cumulative-coating model proposed in this paper is 1.2% and 21.5% higher than that of the two similar models, respectively. Therefore, the approach of 3D cumulative-coating modeling based on inclined distance spraying is discovered, demonstrating the advantages of fast and accurate modeling and enabling accurate 3D cumulative-coating modeling for spraying process simulation.

ВОССТАНОВЛЕНИЕ ИЗНОШЕННЫХ ПОВЕРХНОСТЕЙ ТРЕНИЯ СКОЛЬЖЕНИЯ ГАЗОДИНАМИЧЕСКИМ НАПЫЛЕНИЕМ МЕДНО-ЦИНКОВЫХ ПОКРЫТИЙ

Preliminary studies of copper and copper-zinc coatings obtained by gas-dynamic spraying have shown high mechanical and tribological properties of the formed functional surfaces. The influence of the modes of spraying and subsequent heat treatment on copper-zinc gas dynamic coatings has been little studied. (Research purpose) The research purpose is investigating the effect of technological modes of spraying, as well as subsequent heat treatment of the coating on its phase composition, structure and properties. (Materials and methods) The coating was applied using a Dimet gas dynamic installation with different overlap of the sprayed layers and subsequent heat treatment of the resulting coating at different temperatures and exposure times. The structure of the coating was studied using an X-ray diffractometer and a spectrometer. Cohesive properties were determined on a bursting testing machine by the "ring separation" method, tribological properties were determined on the MT-8 stand during reciprocating sliding of flat mating bodies. (Results and discussion) It was determined that the chemical and phase composition of the copper-zinc coating applied with a displacement of the nozzle by two millimeters and an air flow temperature of 450 degrees Celsius, after heat treatment in the temperature range of 420-430 degrees Celsius and a holding time of 180 minutes corresponds to two-phase brass type L65. The study of the parameters of the copper lattice shows that after exposure in the furnace for 60 minutes, a two-phase structure is formed based on solid solutions of zinc in copper with different copper content and an electronic-type solid solution based on CuZn. (Conclusions) Tribological tests of the copper-zinc coating in the I-20A industrial oil medium revealed the presence of mutual mass transfer of copper and zinc from the coating to the counterbody and vice versa, which is accompanied by a wear-free effect at a load of up to 10 megapascals. The cohesive strength of the copper-zinc coating depends on the time of heat treatment (phase composition) and after 60 minutes of exposure exceeds the initial values (approximately 78 megapascals) and reaches approximately 93 megapascals.

Multicriteria optimization of heat-resistant coatings detonation spraying technology

The paper presents the multi-criteria optimization results of heat-resistant coatings detonation spraying technology. The following criteria for optimization of detonation spraying technology are chosen: critical deformation of coating fracture, adhesion-cohesion equal strength of coating and specific technological cost of coating application. Dependences of the strength properties values of the studied detonation coatings at change of technological and constructive factors have been obtained. It is proved that the greatest influence on the mechanical properties of the studied detonation coatings is exerted by the material of the hardened part and the material composition of the sprayed coating, which is caused by the difference in their thermophysical, chemical and mechanical properties, as well as by the physical and chemical processes occurring during the formation of the sprayed layer. The optimum technological parameters allowing to obtain coatings with specified mechanical properties have been established.

Structural optimization and flow field simulation of gas distribution device in desulfurization tower

AbstractIn order to comply with ultra‐low emission requirements and further reduce the concentration of SO2 emissions from coal‐fired power plants, a novel distributor has been proposed to enhance the uniformity of fluid distribution in the desulfurization tower. The distributor ensures that the inlet flue gas comes into even contact with the slurry droplets ejected from the nozzle, thereby improving the removal efficiency of SO2. The research focuses on a circular desulfurization tower using ammonia‐based desulfurization. To study the enhancement of non‐empty tower desulfurization efficiency, a CFD‐DPM model based on the Euler–Lagrange method has been established. The accuracy of the model has been verified through comparison with experimental or validated data, ensuring its reliability in predicting the performance of the proposed distributor in enhancing desulfurization efficiency in the circular desulfurization tower. The simulation results demonstrate that the addition of the new inflow gas distributor leads to a significantly thinner flue gas escape zone in the circular desulfurization tower. The flue gas flow velocity at the wall side of the tower, above the distributor, increases by only about 1 m/s with the rise of the horizontal cross section, and there is hardly any flue gas escape zone observed. The addition of the distributor increases the pressure drop in the local area, while optimizing the flow field in other areas and reducing the turbulent dissipation energy, which in turn reduces the full tower pressure drop from 701 to 474 Pa. Additionally, the flue gas at the outlet of the distributor is uniformly dispersed, with gas velocity distribution unevenness values of 0.558, 0.587, and 0.601, respectively, which are 15.9%, 14.0%, and 14.0% lower than the unevenness value of the empty tower spraying, at a depth of 1 m below each spray layer. These improvements in gas flow distribution and pressure drop contribute to better control of ammonia escape and aerosol phenomenon, while also enhancing the desulfurization efficiency.

Plasma-Sprayed Coatings Resist Erosion in Wire-Wrapped Screens

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 21158, “Development of Plasma-Sprayed Coatings To Improve the Erosion Resistance of Wire-Wrapped Screens,” by Lukas Ochmann, SPE, and Mohd M. Amro, SPE, TU Bergakademie Freiberg, and Bernd Gronde, Fraunhofer IKTS Hermsdorf, et al. The paper has not been peer reviewed. Copyright 2021 International Petroleum Technology Conference. Reproduced by permission. _ A newly developed coating is put on the outside (i.e., facing the formation) of standard wire-wrapped screens to make the slots erosion-resistant. The coating consists of ceramic or hard metal and is applied by plasma spraying. An extensive development and verification program was conducted to guarantee defined slot widths, corrosion resistance, and mechanical strength of coating and screen. The coating improves resistance against erosion, can withstand corrosive well environments, and features mechanical properties suitable to be safely installed in any well. Thermal Spraying and Composition of Coatings The screens are coated using thermal spraying. This process uses a hot plasma jet to melt powdery materials and apply them to a solid surface. The molten particles solidify on the surface and form a hard coating with little porosity. No chemical reaction exists between the base material and the coating. Several different steps are necessary to coat a wire-wrapped screen. First, the screen is sandblasted in a distinct way to provide a defined surface roughness. After that, a thin bonding layer is applied by thermal spraying. This intermediate layer further improves the adhesion of the functional layer. This erosion-resistant main layer, which consists of hard metal or ceramic, is applied next by thermal spraying. The coating is finished by filling up the pores of the sprayed layers with a liquid sealer. The coating changes the geometry of the slots, slightly reducing the slot size and creating a less-sharp slot opening. By adjustment of the process parameters of the thermal spraying and choice of the correct initial slot width, defined and constant slot widths can be produced for the final product. Corrosion Investigation All samples and future prototypes are based on 1.4404 (316L) stainless steel. Combinations of four bonding layers, six functional layers, and five sealers were investigated. In total, 237 different samples were corroded under different conditions. The samples were submerged halfway into the brine so that the effect of the three-phase interface (brine, gas, and sample) could be investigated over a period of multiple weeks (minimum 3 weeks, maximum 18 weeks) at 60°C. Further experiments were conducted with nitrogen and hydrogen atmospheres for 3 weeks. The first tests were conducted with samples made from wire-wrapped screens. A second batch of tests was performed with coupons for tensile bond tests.

Finite element modeling of the electrical impedance tomography technique driven by machine learning

To create a human-like skin for a robotic application, current touch sensor technologies have a few drawbacks. Electrical Impedance Tomography (EIT) is a candidate for this application due to its applicability over complex geometries; nevertheless, it has accuracy concerns. This study employs artificial neural networks (ANNs) to investigate the accuracy and capability of EIT-based touch sensors. A finite element (FE) model is utilized to solve the forward EIT problem while simultaneously determining the system’s comprehensive mechanical response. The FE model is comprised of a polyurethane (PU) foam domain, a conductive spray layer and a set of sixteen electrodes. To replicate the process of touching the sensor body, a punch of varying diameters and touch forces is utilized. The mechanical response of the sensor body is modeled using the hyperfoam material model calibrated through experimental uniaxial and shear test data, while the electric conductivity of the sprayed skin surface is obtained experimentally as function of applied strain. The viscoelastic behavior of the PU foam material is also obtained experimentally. These experimental data were implemented in the FE model through user subroutines to model the mechanical and electrical properties of the sensor in the EIT forward problem. The traditional EIT inverse problem image reconstruction was replaced utilizing ANNs as an alternative to extract mechanics based parameters. The ANNs were created to predict the spatial coordinates of the touch point, and they were proven to be extremely accurate. Using the EIT voltage readings as input, the ANNs were utilized to forecast the system’s mechanical behavior such as contact pressure, contact area, indentation depth, and touching force.

Visually activated sprinklers applied in atria to mitigate the interaction of water spray with the smoke layer

This research investigates the fire suppression effectiveness of sprinklers in a large atrium of a public transport hub in Taipei, Taiwan, during a fire using FDS. The thermally-activated sprinkler had the shortcoming of delayed activation, with a thick smoke layer accumulating at the ceiling. Thereafter, the interaction of sprinkler spray with the thick smoke layer would cause a large amount of smoke falling to the floor level, significantly impacting safe egress. The novelty of this study is to couple a sprinkler system with a vision-based fire flame detection system (VFDS) having the advantage of locating the fire instantly to suppress fire. A combination of different atrium heights, fire sizes, and scenarios for a total of 27 cases were investigated. The research results have indicated that VFDS-activated sprinklers can suppress an atrium fire at the early stage, greatly reduce the amount of smoke generation and smoke accumulation. In consequence, the interaction of water spray and smoke layer is largely mitigated to prevent early fall of smoke. When the fire is suppressed, the atrium can maintain a clear height that is crucial to safe egress. The research finding of VFDS-activated sprinklers system is significant for fire safety of buildings with large atria.

Teflon-Based Gas Diffusion Electrode with a Novel Current Collector Concept for Scalable Highly Efficient CO2 Reduction Electrolyzers

In this work we developed a novel type of GDE that combines a PTFE membrane as GDL with an on top sprayed copper catalyst layer and a polymer coated metallic current collector. It is well known that PTFE based GDE`s are a good solution to circumvent flooding phenomena, however the scalability was so far not addressed in the CO2 reduction field. To use PTFE based GDE`s industrially we developed a metallic current collector with polymer coating and show different methods of implementing those. We will show the basic concept of the idea and the validation in lab scaled electrolyzes (5 cm2 and 100 cm2) and will give a future outlook on further development and use-case scenarios.

Efficient degradation of dye wastewater by catalytic ozonation reactive ceramic membrane with facile spraying of nano Ti[sbnd]Mn oxides: A pilot scale attempt

The traditional treatments of dye wastewater exist obvious drawbacks of low efficiency but high energy consumption. To solve this problem, based on the concept of combining degradation and separation, an integrated process of TiMn oxides catalytic ozonation and ceramic membranes (CM) was proposed to degrade dye wastewater in this paper. Specifically, TiO2/MnO2 hybrid catalysts were loaded on the surface of CM with a spraying printing method to prepare a reactive ceramic membrane (TiO2/MnO2-CM). The degradation efficiency and permeate flux of the TiO2/MnO2-CM + O3 system on Rhodamine B (RhB) were investigated. The SEM results illustrated that the catalyst was successfully loaded on the surface of CM. Additionally, the degradation efficiency of RhB was 100 % in 40 min under the conditions of catalyst spray layers 12, ozone concentration 2.5 g/cm3, and initial concentration of RhB 20 mg/L, and the permeate flux of TiO2/γ-MnO2-CM was as high as 125.399 kg/ (m2·h). Supplementarily, the study revealed that TiO2/γ-MnO2-CM could increase the concentration of ozone in water and catalyze ozone to produce more hydroxyl radicals (•OH), and the concentration of dissolved ozone was 0.7545 mg/L, •OH 68.16 μmol/L respectively. Eventually, the catalytic ozonation TiO2/γ-MnO2-CM device was scaled up, which treated 96 L RhB with a degradation efficiency of 100 % in 50 min. The work gives a solid foundation and scientific value for the industrial application of reactive CM in water or wastewater treatment.