Plate Roughness Research Articles

Effects of Gigantochloa apus String Bamboo Fiber Brushes on Heat-Cured Acrylic Resin Plate Surface Roughness.

Purpose: The objective of this study was to assess the impact of string bamboo fiber brushes (Gigantochloa apus) on the surface roughness of heat-cured acrylic resin plates. Materials and Methods: This study used a pretest and posttest laboratory experiment with a control group design, with data obtained from the average surface roughness values of heat-cured acrylic resin plates after brushing using bamboo silk fiber brushes as the test group and conventional denture brushes as the control group. Results: The Shapiro-Wilk test showed that the data were normally distributed, with a total of 32 samples of heat-cured acrylic resin plates (p=0.794). The results of this study found that the average surface roughness values of the anatomical surface of heat-cured acrylic resin plates after being brushed with string bamboo fiber brushes were 0.20 µm and 0.18 µm for the nonanatomical surface. The difference in the average surface roughness of the heat-cured acrylic resin plates, both on anatomical and nonanatomical surfaces, before and after brushing with string bamboo fiber brushes, was 0.0001 (p < 0.05). Conclusion: Bamboo denture toothbrushes exhibit a lower abrasive effect than nylon denture toothbrushes, with the abrasiveness remaining below the threshold requirements established for dental materials.

Development of a New Correlation Model for Heat Transfer in Solar Air Heater with Corrugated Absorber Plates Using Swarm Optimization

Solar air heaters play a crucial role in distributing heated air at low to medium temperatures. The heart of these systems lies in the absorber plate, which directly absorbs solar heat energy and then efficiently transfers it to the flowing air. However, the challenge lies in achieving optimal thermal efficiency by modifying the absorber plate roughness. Traditional smooth absorber plates have a limited contact area for heat transfer, leading to suboptimal performance. Using passive techniques, such as corrugation on the absorber plate, may increase thermal efficiency by creating turbulence in the laminar sublayer. In this study, corrugated solar air heaters are considered, with the absorber plates roughened into square, semicircular, and triangular ribs. The flow characteristics of heat due to the roughness of the absorber plate is simulated using the computational fluid dynamic (CFD) technique. The ANSYS Fluent 2019R3 is used to investigate the turbulent air flow in the absorber plate. The simulation analyses are performed over a Reynolds number range of 4000–18,000 using three different pitches. As the main contribution, two different model equations, namely M1 and M2, for the correlation model of the solar heat transfer were proposed to predict the Nusselt number, where M2 is an original model and M1 is newly established with the fine-tuned coefficients. Also, for the first time in the literature, the recent swarm optimization algorithm, namely Honey Formation Optimization with Single Component (HFO-1), is used to optimize the solar air heater and a comparison study with a popular non-swarm optimization, namely the Generalized Reduced Gradient (GRG) optimization, is provided. The Nusselt number was obtained using HFO-1 with a percentage error (MAPE) of 2.15% and 0.86% for the models M1 and M2, respectively. Moreover, the average achievement of HFO-1 on the proposed correlation models is 50% better than that of the GRG optimization, with respect to the RMSE.

Numerical Investigation of Flow Characteristics in Internally Flowing Pipes with Varying Roughness and Helical Angles of Vortex Generators

In this study, the turbulent behavior inside a pipe containing an aluminum helical vortex generator plate was investigated using computational fluid dynamics (CFD) methods, considering different plate roughness and helical angle values. Accordingly, numerical analyses of velocity and pressure distributions for a liquid flow with a constant inlet velocity of 0.5 m/s and four different helical angles were performed and compared in a computer software. To observe the effects of the roughness values of the metal plate on flow behavior, analyses were conducted for three different roughness values for each helical angle and the results were compared and interpreted. As a result of the study, the combination of a roughness value of 0.04 and a helical angle of 0° led to the highest pressure and velocity values, while the same roughness value combined with a 270° helical angle resulted in the lowest pressure and velocity values. Detailed analysis showed that helical angles (90° and 180°) presented moderate pressure and velocity values, indicating a non-linear relationship between helical angle and flow characteristics. The results demonstrate that optimizing the helical angle and roughness is crucial for enhancing the efficiency of vortex generators. This way, a design will be developed to prevent performance degradation in industrial applications that require flow efficiency and pressure management.

Macro-micro investigation on the coefficient of friction on the interface between steel and cast-in-place UHPC

The interface friction force between steel and Ultra-high performance concrete (UHPC) can significantly enhance the shear loading capacity and fatigue performance of steel-UHPC composite structures. Current research on interface friction primarily focuses on the coefficient of friction (COF) on steel-concrete interface. However, using the COF of steel-normal concrete (NC) interface to assess the steel-UHPC interface performance might be debatable and lack accuracy, due to the substantial differences in material properties and compositions between UHPC and NC. In this study, the COF on the interface between the steel plate and cast-in-place UHPC was investigated, and the effects of the steel plate roughness and interface normal stress on the COF were considered. The COF of steel-UHPC was compared with those of steel-NC. The steel plate surface microstructure was also tested using a microscope after experiments. It is recommended that the COF between UHPC and NC and a natural steel plate should be considered as 0.803 and 0.704, respectively, under interface normal stress levels ranging from 0.5 MPa to 9 MPa. The adopted COF in the existing numerical analyses for steel-UHPC structures was conservative, underestimating the value by 37.73 % to 62.64 % compared to the recommended value in this paper. Moreover, when the steel plate roughness of steel-UHPC specimens increased by 1.324 times, the maximum increase in the COF was 11.75 %. However, when the interface normal stress increased by 17 times, the COF on the steel-UHPC interface decreased by a maximum of 12.57 %. Compared to steel-NC specimens, the COF of steel-UHPC showed a maximum increase of 14.25 % under an interface normal stress of 0.5 MPa and 12.98 % under an interface normal stress of 9 MPa.

Film Cooling Performances Under Various Upstream Roughness Conditions: Experimental Investigations and Similarity Hypothesis

Abstract Roughness caused by deposition, erosion, and additive manufacturing can significantly affect gas turbine efficiency. Previous research has often examined film cooling performance under limited roughness configurations, resulting in inconclusive findings. In this study, film cooling performances under various upstream roughness conditions were investigated to simulate the roughness-affected film cooling performance of the suction side and the endwall. Three roughness heights (k/D = 0.1, 0.2, and 0.4) and shapes (ks/k = 0.17, 0.67, and 1.95) were selected to cover a wide range of surface roughness characteristics. Three blowing ratios were examined (M = 0.5, 1.0, and 1.5). The weakly roughened surfaces showed improved cooling effectiveness as k/D increased. Meanwhile, the moderately and severely roughened surfaces showed a decrease in cooling effectiveness with increasing k/D at M = 0.5 and 1.0 but an increase at M = 1.5. Cases with shallower and higher roughness elements at M = 1.5 outperformed the smooth plate. Subsequently, a similarity hypothesis for film cooling effectiveness was proposed. At all blowing ratios, the scaled cooling effectiveness profiles converged around the smooth plate results for ks/D &amp;lt; 0.391, encompassing common turbine roughness scales, including irregularly roughened surfaces. Deviations emerged at ks/D = 0.782, and they were correlated with the deteriorated regions observed at various blowing ratios. Ensemble-averaged scaled cooling effectiveness exponentially grew with increasing roughness scale for all blowing ratios, and empirical expressions based on smooth plate result and roughness scale were proposed.

Physical and Chemical Properties of High-Temperature Silicone-Based Polymer Coatings Applied on Different Surface Roughnesses

High-temperature coatings play a crucial role in protecting surfaces exposed to extreme temperatures, corrosion, and other harsh environments. This paper focuses on the physical and chemical properties of solvent-borne and water-borne high-temperature silicone-based polymer coatings applied on two types of surface roughness of carbon steel plates. The corrosion protection performance of the coatings was characterized using a salt spray chamber, humidity chamber, electrochemical impedance spectroscopy (EIS) measurements, and differential scanning calorimetry (DSC). The physical properties of high-temperature coatings were determined using the Shore D hardness method and cross-cut adhesion tests. This study investigates the effects of different surface preparation methods on coating adhesion, which is considered to be a crucial property of organic coatings for corrosion protection durability. The thermal stability of the coating was tested using furnace cyclic testing. The results show that high-temperature coatings in general exhibit excellent thermal stability, high adhesion strength, and good resistance to warm and humid environments, except in the conditions of a salty atmosphere. This study reveals that coating performance is affected by the composition and surface preparation method. This study can be useful for coating manufacturers and researchers interested in understanding the physical and chemical properties of high-temperature coatings and their applications in various environments.

Influences of various parameters on shear stiffness of bolted joints subjected to shear load

Parameters which affect shear stiffness characteristics of bolted joints subjected to shear load should be elucidated in order to design mechanical structures for functionality focusing not only on their strength and self-loosening but also on their shear stiffness. In this study, we have both experimentally and analytically investigated the behaviors of a bolted joint subjected to shear load and primary parameters which determine the shear stiffness characteristics of bolted joints. The experiments have been conducted applying the shear load four times repeatedly on clamped plates of a bolt/nut assembly with washers. We measured the shear stiffness of bolted joints and the shear load at which the slippage started to occur between the clamped plates. Four types of washers were used in the experiments with different contact areas on the clamped plates in order to reveal the effect of contact area of washers. We also conducted FE analysis under the same conditions. As the results, it was seen that the shear stiffness slightly increased with an increase in the clamp force of bolted joint. The shear stiffness was not influenced by the number of loading cycles. It was also seen that the amount of rotational deformation in the bolted joint depended on the slippage between the clamped plates. Although the rotation deformation was very small until the slippage occurrence, the rotational deformation remarkably increased after the slippage occurred. In general, it is well-known that the joining portion of lap jointed plates by spot welding, for example, slightly and rotationally deformed, but it has never been elucidated that the inclination angle due to the rotational deformation depends on the slippage between the clamped plates in the bolted joint. It was also seen that the shear stiffness until the slippage occurrence increased with an increase in the contacting surface area between the clamped plates. Although we investigated the effect of surface roughness of the clamped plates only in the experiments, we cannot clearly reveal its effect on the shear stiffness. But it is seen from the FE analysis result that the friction coefficient between clamped plates had a slight influence on the shear stiffness. The result shows that the shear stiffness of bolted joint mainly depends not only on the slip resistance between the clamped plates but also on increase of the contact surface between the washers and clamped plates. The results can be applied in order to control the shear stiffness of lap-jointed plates by spot welding and so on.

Influence of Initial Surface Roughness on LIPSS Formation and Its Consecutive Impact on Cell/Bacteria Attachment for TiAl6V4 Surfaces (Adv. Mater. Technol. 12/2023)

Laser-Induced Structuring In article number 2201802, Lamborghini Sotelo, Silke Christiansen, and co-workers demonstrate Laser-Induced Periodic Surface Structures (LIPSS) for a one-step micro and nano surface structuring of different surfaces; however, their formation process still presents an open problem. This study explores the influence of the initial surface roughness of metal plates on the formation of LIPSS. The generated structures are then tested as biocompatible surfaces for bone implant treatment.

DETERMINATION OF SLIP‐FACTOR BETWEEN FRICTION SHIMS AND SHOT‐BLASTED STEEL SURFACES

AbstractThis paper presents the results of an experimental testing campaign performed to determine slip‐factor between the faying surfaces of shot‐blasted steel plates and state‐of‐the‐art friction shims. In total five experimental tests were performed as consistent with the provisions of EN1090‐2 Annex G to determine the slip‐factor between the faying surfaces. The results of the experimental test campaign showed that the surface roughness of the steel plates needs to be suitable for the selected type of the friction shims to enrich the slip‐resistance of the bolted‐connections. The test procedure was simulated with a commercial finite‐element analysis software, Abaqus, to compare the empirically determined slip‐factor and the penalty friction formulation of the software. It is shown that the slip‐factor definition of EN1090 – 2 Annex G fits in a very good agreement to the penalty friction formulation of the software to estimate the slip‐resistance of the bolted connections. The differences between the test results and the outputs of the finite element analysis are discussed in detail with a novel representation of non‐linear stick‐slip transition path for the slip‐resistant bolted connections. A further parametric study was performed to understand the impact of the geometric parameters on the slip‐resistance and the load‐slip behaviour of the faying surfaces.

Influence of magnetic-abrasive machining parameters on ceramic cutting tools for technological quality assurance of precision products from cold-resistant steels

In connection with the development of the Far North and Siberia, the issues of wear resistance of equipment and technological methods for processing precision products from cold-resistant steel are of particular relevance. At low temperatures, steel exhibits a loss of ductility and toughness and an increased tendency to brittle fracture. The achievement of the required quality of machining of precision products made of cold-resistant steels is significantly influenced by the tool and the technology of its manufacture. One of such tools involved in the processing of cold-resistant steels is ceramic plates of the VOK-60 brand. This article discusses an alternative method of finishing a tool based on cutting ceramics &ndash; magnetic abrasive processing. This is a modern solution for tool processing, which allows you to obtain high quality workpieces from cold-resistant steels with minimal defects in their surface layer. The quality of the surface layer of the product during magnetic abrasive processing is influenced by many parameters, some of which will be studied in this article: electromagnetic induction, processing time, rotational speed and feed rate. The influence of these input parameters on the surface roughness of ceramic plates will be considered taking into account the combined influence on each other. The success of application of magnetic abrasive processing can be judged by the topography of the surface of the cutting ceramic plates, made using an electron microscope, as well as the results of roughness analysis using a profilometer. The data obtained during the study demonstrated the importance of individual input factors in the processing of products. Based on the results of experimental studies, recommendations have been formulated to improve the efficiency of applying the process of magneticabrasive processing in the preparation of ceramic cutting plates.

Investigation of Machining Parameters in Thin-Walled Plate Milling Using a Fixture with Cylindrical Support Heads

Construction, processing, biomedical instruments, electronics, automobiles, and aerospace widely use thin-wall parts. Mostly, these thinwalled parts are machined using either a peripheral milling machine or an end milling machine with the help of fixtures. In this study, three different material thin-walled parts (i.e., Inconel 718, AISI 316L, and Al 6061) are machined in end milling using a newly designed fixture with cylindrical heads, and the surface roughness and deformation with different machining parameters are compared. The optimum values of the machining parameters feed, speed, and depth of cut have been found to improve the surface roughness of thin-walled plates by arresting the deformation using the proposed fixture. Analysis of variance (ANOVA) results show that the speed is the most influential parameter in the case of displacement for AISI 716L and Al 6061, feed is the most influential parameter in the case of surface roughness for Inconel 718 and AISI 716L, and speed is the most influential parameter in the case of displacement and surface roughness for Al 6061. The use of fixtures provides a significant reduction in the deformation and surface roughness during the machining in end milling machine.

Analysis of the Influence of Build Plate Pre-Treatment and Process Parameters on the Bonding of Additively Manufactured Parts of TiAl&lt;sub&gt;6&lt;/sub&gt;V&lt;sub&gt;4&lt;/sub&gt; to the Build Plate

In this paper, the influence of the surface roughness of build plates as well as the process parameters laser power, scan speed and exposure curing time on the bonding of additively manufactured components made of TiAl6V4 to the build plates is analyzed. These analyses are carried out with build plates made of Titanium Grade 2 and AlMgSi0.5. The analyses show that higher surface roughness leads to lower bending strength and thus poorer bonding of components on the build plate. In addition, it is shown that the bending strength normalized to the bonding surface decreases at high laser power, especially at high scanning speeds. Furthermore, multiple exposure results in lower flexural strength.

Bionic coating imitating reflection characteristics of plant leaf in solar spectrum waveband for hyperspectral camouflage

Imitating the reflection characteristics of plant leaves in solar spectrum waveband with bionic coatings can effectively counter the hyperspectral detection technology in the vegetation background. Herein, inspired by the formation mechanisms of the reflection characteristics of plant leaves, a bionic coating containing chromium oxide (Cr2O3) particles and a hydrophilic inorganic salt dispersed in a polyvinyl alcohol (PVA) matrix is prepared on metal plates, and a theoretical model was constructed to clarify the bionic mechanisms. Results show that the Cr2O3 particles exhibit absorption characteristics similar to those of chlorophyll and scattering characteristics similar to those of multilayer cells in plant leaves, thereby enabling the bionic coating to imitate the reflection characteristics in the visible and near-infrared waveband. Meanwhile, the hydrophilic inorganic salt can absorb moisture molecules in the air when the bionic coating is placed in natural environments, thereby absorbing incident radiation and imitating the water absorption valleys. Moreover, it was found that there is only non-freezing bound water in the bionic coating with a differential scanning calorimeter, thus the moisture absorption processes associated with the hydrophilic hydroxyl groups in PVA matrix were considered when determining the mass transfer characteristics in a natural environment. In the whole solar spectrum, the bionic coating can significantly suppress the high reflectance of the metal plates when the volume fraction of Cr2O3 particles is 0.81 % and the coating thickness is greater than 0.2 mm. Increasing the surface roughness of the metal plates can further improve the suppressing performance in the range from 800 to 1300 nm, achieving a better similarity of the reflection curves between the bionic coating and the plant leaves. The outstanding imitation performance of the key reflection characteristics of the plant leaves confirms the remarkable application potential of the bionic coating in the field of hyperspectral camouflage.

Investigation on interfacial properties of conventional and functional modified TiO2/water nanofluids

The interfacial properties of conventional and functional modified nanofluids, including tension and contact angle, are investigated experimentally. The conventional nanofluids are prepared by mixing pure TiO2 nanoparticles into water containing surfactants, and the functional modified nanofluids are prepared by adding 3-aminpropyltriethoxysilane (APTS) or γ-glycidoxypropyltrimethoxysilane (GPTMS) treated nanoparticles into water. The results show that the surface tension of both conventional and functional modified nanofluids shows a decreasing trend with the elevating nanoparticle concentration and temperature. The surface roughness of copper plates as well as the nanoparticle loading would both have obvious effects on the contact angle. The surface tension and contact angle of conventional nanofluids decrease with the increasing surfactant concentration. Among all tested samples, the APTS modified nanofluids have larger surface tension and contact angle, which indicates a poorer wettability. The sodium dodecyl sulfate (SDS) added nanofluids have better wettability, in which smaller surface tension and contact angle are found.

Modeling of processing parameters for the cutting of rolled tungsten plates via abrasive water jet

Tungsten is a promising candidate for plasma-facing material in tokamaks. This study aims at determining whether the cut-surface roughness of rolled tungsten plates (RTPs) can be improved using an abrasive water jet (AWJ) through tests combined with modeling of the cutting-process parameters. Based on the key factors affecting the cut-surface roughness, the magnitude and type of test factors were increased, compared with the previous study. A batch test was designed and conducted to investigate the use of an AWJ to cut an RTP and obtain more comprehensive sample data. In addition, the multivariate linear regression method was employed to establish a multivariate quadratic response surface regression model of the relationship between the cutting-process parameters and the cut-surface roughness based on the roughness sample data. Moreover, a backpropagation (BP) artificial neural network (ANN) model was developed based on the cutting-process parameters to predict the cut-surface roughness. The two models were compared and experimentally validated, which showed that the BP ANN model exhibits relatively high accuracy. Thus, the established model can help to improve cut-surface quality and cutting efficiency.

Electrochemical Aging and Characterization of Graphite-Polymer Based Composite Bipolar Plates for Vanadium Redox Flow Batteries

Three bipolar plates (BPP) comprised of a composite of polypropylene or polyvinylidene fluoride polymer and varying average graphite particle size were studied for application in a vanadium redox flow battery (VRFB). The BPPs were electrochemically aged via 3000 cyclic voltammetry curves in 1.8 M VOSO4 + 2.0 M H2SO4 electrolyte. After every 500th cycle the aging progression was determined by performing cyclic voltammetry on the bipolar plates in 0.1 M H2SO4 solution where the double layer capacitance, the quinone/hydroquinone and the vanadium species redox activity were quantitatively evaluated. Prior to the aging, the composite plates were extensively characterized using various physical methods. The performed studies reveal that the wettability, surface roughness and accessible porosity of the bipolar plates significantly influence their electrochemical stability. Cycling tests in vanadium redox flow single cells at a constant current density of 60 mA cm−2 revealed a close correlation of the cell efficiencies to the electrochemical stability of the bipolar plates. Thus, the proposed electrochemical characterization method can be an effective foresight to predict the applicability of a bipolar plate in a vanadium redox flow battery.

The normal force evolution of the substrate during the withdrawal process

AbstractThe evolution of normal force on the smooth plate immersed in Newtonian and yield stress fluids was investigated during the dip coating. The influences of withdrawal velocity, liquid rheological property, and plate roughness were elaborated. For all fluids, the variation of force versus the withdrawing height was divided into four stages. Importantly, the control forces for coating in each stage were determined, which are in turn viscous force‐capillary, viscous force‐gravity, capillary‐viscous force, and gravity. The critical value of normal force controlled from capillary to viscous effect during drainage was adopted to calculate the surface tension. The possibility of measuring the surface tension was verified under the negligible interference of viscous effect and film instability through a detailed analysis on the evolution of force in a series of tests. Accordingly, the applicable conditions with the low withdrawal speed, high viscosity, and rough surface were finally achieved. This work can provide a theoretical basis for the film‐formation mechanism and surface tension measurement in dip coating.

Effect of surface structure on the kinetic of THF hydrate formation

The most important aim of this study is to check the surface effect on THF/H2O hydrate formation by the volumetric method [Asadi et al. J. Mol. Liq., https://doi.org/10.1016/j.molliq.2019.111200]. A wide variety of experiments have been conducted to investigate effective parameters on hydrate formation. Suitable additives and operational conditions have been already studied while the effect of other parameters including surface efficacy has not been considered. Hence, the experiments have been done at atmospheric pressure in a cell that has a prefabricated surface. Therefore, the modified surfaces used here are 304 stainless steel specimens with specific roughness which have been coarsened through laser. Since the roughness and wettability of metallic plates play a critical role in hydrophobicity or hydrophilicity of surfaces, the contact angles have been measured between 123.00 and 23.47°changing the speed of laser radiation. It is demonstrated, increasing radiation speed forms a hydrophilic surface. Moreover, hydrate nucleation and growth have been rapidly recorded via volume changes of solution. Subsequently, the most effective surface has been recognized according to induction and relaxation time as well as the rate of hydrate formation. The results show that developing a hydrophilic surface, the rate of THF hydrate formation is highly increased. Therefore, this study can provide a new viewpoint in the relation of surface structure and the kinetics of THF/H2O hydrate formation.

Evaluation of surface changes of stainless steel miniplates and screws following retrieval

The objective of the present study is to evaluate the surface changes like corrosion, surface roughness, micro-fractures and tensile strength of stainless steel mini plates and screws. The study was carried out at the Department of Oral and Maxillofacial Surgery, Meghna Institute of Dental Sciences, Nizamabad for a duration of 3 years. Around 34 stainless steel miniplates and 101 stainless steel screws complied to treat maxillofacial fractures of 20 patients for the rigid internal fixation were retrieved. Then the surface changes like corrosion, surface roughness, micro-fractures were evaluated using stereo microscope and scanning electron microscope whereas the tensile strength was measured using a universal testing machine.: The surface roughness and micro-fractures were seen in 100% of the stainless steel miniplates and screws whereas corrosion degradation was seen in 65%. Thereafter, when the tensile strength was evaluated, a mean value of 497N was found to be exhibited by the retrieved miniplates which was enough to withstand the masticatory forces. Through our study, we emphasize to the need for the proper handling techniques to be followed at the time of implant placements so as to avoid implants failures and occurring of other biogenic complications.

Experimental Study of the Factors Influencing the Performance of the Bonding Interface between Epoxy Asphalt Concrete Pavement and a Steel Bridge Deck

The bonding between pavement and a steel bridge deck is a key component affecting the structural integrity of steel deck pavement and delamination is a major cause. The bonding interface of steel deck pavement was systematically investigated to evaluate the interactive influences of factors, such as the air void of the asphalt concrete pavement, the surface roughness of the steel deck, the thickness of the zinc-rich epoxy primer, and the waterproof bonding membrane, on the bond strength of the pavement interface, through simulated loading, brine immersion, pull-off, and interface observation experiments. The results show that a low air void (&lt;3.0%) was a necessary condition for the corrosion resistance and bonding reliability of the steel deck pavement structure, and a zinc-rich epoxy primer provided an additional guarantee for corrosion resistance of the steel deck pavement; additionally, the combination of steel deck plate roughness in the range of 120–140 μm and zinc-rich epoxy primer thickness in the range of 80–110 μm led to a high bond strength, which was also conducive to the corrosion resistance of the steel bridge plate. The steel deck pavement structure should be designed through combinatorial optimization of multiple factors to create an integrated waterproof and anticorrosion bonding system.