Grit Sandpaper Research Articles

Experimental Investigation of Biofouled Ship Control Surface Performance

Abstract Marine biofouling threatens ship safety by causing unexpected control surface performance. To explore these adverse biofouling effects, this paper presents the results of wind tunnel testing using a model-scale, low aspect ratio NACA 0018 control surface. Simulated calcareous biofouling was introduced as coarse-grit sandpaper, and, uniquely, roughness locations and sandpaper grits were varied to better understand any resulting degradation in hydrodynamic performance. Direct experimentation at high (turbulent) chord Reynolds number values suggests that leading-edge biofouling with 36-grit sandpaper results in worst-case performance, with the control surface's average lift-to-drag ratio reduced by 63%. Additional findings are presented, and recommendations for future experimental work are also provided.

Development of an automated radial scanning microscopy-based imaging system and its use for measuring resin canal size and frequency in Pinus taeda

Summary Resin canals produce and transport oleoresins that are important for tree defenses within the Pinaceae family. Rapid measurement techniques are needed to better understand how resin canal characteristics vary due to genetic and environmental effects. Here we describe a semi-automated microscopy imaging system that was built for quantifying longitudinal resin canals. Tree increment cores from 210 loblolly pine (Pinus taeda L.) trees were prepared into radial strips and the transverse surface of the samples polished with 400 and then 600 grit sandpaper. Each sample was imaged along its entire length (pith to bark) with the images collected from a monochrome camera connected to a Plan Fluorite 4× objective lens. The samples were imaged on the transverse surface via transmitted 850 nm near-infrared light directed at the radial surfaces of the samples. A total of 24 153 images were collected and then processed offline in Python using the Open Computer Vision Library (OpenCV) using a series of algorithms including contrast correction, noise removal, thresholding, contour identification, erosion, and dilation. A total of 24 491 resin canals were identified and their size quantified. The resin canals were assigned into annual rings and positioned within the earlywood or latewood of a ring using cross-correlation whereby a pseudo-density value was derived from the images and matched with density values measured by X-ray densitometry. Of the total resin canals identified, 51.5% were in the earlywood and 48.5% in the latewood, with the majority being detected in the earlywood in the first six years and the latewood in years 7 and above. This study represents the most information collected on the resin canals of loblolly pine. The detailed description of the hardware and image analysis methods should serve as a useful guide to others interested in imaging resin canals as well as other anatomical features.

Fabrication of fluorinated superhydrophobic oil-absorption cabins with controllable movement, elasticity, and wear resistance

Superhydrophobic materials that can withstand harsh environments are critical in oil spills. Here, fluorinated superhydrophobic monoliths were prepared in one step based on a high internal phase emulsion (HIPE) templating method. γ-methacryloyloxypropyltrimethoxysilane (KH570)-modified Fe3O4 nanoparticles were added into the emulsion as co-stabilizers and participated in the composition of micro-nano hierarchical structures. The fluorinated alkyl backbone and rough structure enabled the foam to exhibit excellent superhydrophobicity with a water contact angle (WCA) of 153.5° and a sliding angle (SA) of 5.92°. The unique structure and composition of the foam allowed it to maintain stable superhydrophobicity (153.97°) even after severe sandpaper abrasion tests (Drawn 10 m at 7.1 kPa on P400 grit sandpaper). It also demonstrated exceptional hydrophobicity to strong acids, bases, and UV light. The oil-saturated material can be regenerated through a simple extrusion process, showing outstanding reusability. After ten cycles of oil adsorption, the adsorption capacity remains above 90 % of the initial value. The additional magnetic properties of the material enable it to remove oil in confined or hazardous conditions. More importantly, with the assistance of a vacuum pump, the material permits continuous separation of organic solvents from the water. These excellent properties of the foam make it a potential material for treating wastewater.

An effective textured Novel Object Recognition Test (tNORT) for repeated measure of whisker sensitivity of rodents

Rodents use their whisker system to discriminate surface texture. Whisker-based texture discrimination tasks are often used to investigate the mechanisms encoding tactile sensation. One such task is the textured Novel Object Recognition Test (tNORT). It takes advantage of a tendency of rodents to explore novel objects more than familiar ones and assesses the sensitivity of whiskers in discriminating different textures of objects. It requires little training of the animals and the equipment involved is a simple arena with typically two objects placed inside. The success of the test relies on rodents spending sufficient time exploring these objects. Animals may lose interests in such tasks when performed repetitively within a limited time frame. However, such repeated tests may be crucial when establishing a sensitivity threshold of the whisker system. Here we present an adapted rodent tNORT protocol designed to maintain sustained interest in the objects even with repeated testing. We constructed complex objects from three simple-shaped objects. Different textures were provided by sandpapers of varying grit sizes. To minimise olfactory clues, we used the sandy and the laminar side of the same sandpaper as the familiar and novel textures assigned at random. We subsequently conducted repeated tNORTs on eight rats in order to identify a critical threshold of the sandpaper grit size below which rats would be unable to discriminate the sandy from the laminar side. With an inter-test-interval of seven days and after five tNORTs, the protocol enabled us to successfully identify the threshold. We suggest that the proposed tNORT is a useful tool for investigating the sensitivity threshold of the whisker system of rodent, and for testing the effectiveness of an intervention by comparing sensitivity threshold pre- and post-intervention.

Enhancing the PEEK composites-titanium interface performances through electrochemical treatment in fibre-metal laminates for aerospace applications

In this work, different surface treatments were investigated to improve the adhesion between grade 5 titanium alloy and carbon fibre-reinforced PEEK composites for aerospace applications. Three types of processes were compared: mechanical treatment (MT), carried out by sander with #80 grit sandpaper, chemical treatment, using a silane coupling agent (SIL) and electrochemical treatment, performed by anodic oxidation. The latter was performed by using an ethylene glycol solution composed of 0.5%wt of ammonium fluoride (NH4F) and variable volume content of deionized water: 5%v/v, 20 % v/v, 50 % v/v. The ammonium fluoride content was fixed, while the ethylene glycol percentage depend on the variation of water volume. Two values of electric potential were evaluated: 30V and 50V. Finally, for each potential and water content, three different anodizing times were studied: 10 min, 30 min, and 60 min. Morphology studies were performed through Scanning electron microscopy to evaluate how the anodizing parameters could affect the shape of the nanotubes (NTs) layers. Moreover, short beam shear tests were carried out to evaluate the achieved improvement given by the different surface treatments.

Development and effect of orodispersible film incorporated with Biosilicate for remineralization of dental enamel subjected to cariogenic and erosive challenge.

The objective of this in vitro study was to assess the efficiency of incorporating Biosilicate particles (30 and 50 mg) into an experimental orodispersible film and its efficacy in the remineralization process of bovine dental enamel under cariogenic and erosive challenges. Ninety-nine intact incisors, devoid of cracks or fractures, yielding 198 samples (6 × 6 × 2 mm) via vestibular sectioning using a low-speed diamond disc under water cooling. After flattening the enamel surface with 600, 1200, and 2000 grit sandpaper, the samples were divided into two groups based on the challenges they underwent: cariogenic (0.1 M lactic acid at pH 5.0) or erosive (0.05 M citric acid solution at pH 2.3). Samples from each challenge were further categorized into 11 groups (n = 9) according to the duration of cariogenic (3, 7, and 14 days) or erosive (3, 7, and 10 days) challenge, along with positive control groups (fragments untreated with challenges and treated with different Biosilicate concentrations) and negative controls (fragments treated with artificial saliva for the same periods established for cariogenic and erosive challenges). Treatments with orodispersible films containing Biosilicate (30 and 50 mg) were administered for 2 min per day for 15 days. The highest remineralizing potential was observed in samples treated with Biosilicate after 14 days of cariogenic challenge, irrespective of the concentration tested. For samples subjected to erosive challenge, erosion time did not affect Biosilicate's remineralizing potential. Biosilicate shows promise in terms of remineralizing potential in enamel subjected to cariogenic challenge due to its ability to form hydroxycarbonapatite in mineralized tissues.

Supporting Manufacturing Process Changes with an Innovative Microscopy Method

Abstract Bakelite Chemicals LLC has developed an innovative microscopy technique to view adhesives “in use.” The cornerstone of the method is based on sample preparation. Samples of a composite wood product are sanded to a highly polished surface using a progression of sandpaper grits from lowest to highest. This preparation technique differs significantly from historical preparation techniques, which rely on soaking or embedding samples followed by thin-section creation using a microtome. The wet preparation technique causes wood cells compressed during production of the composite to swell and change how the adhesive is seen within those cells. The addition of water to the sample can also move uncured adhesive around the bond line. These changes can significantly alter the interpretation of how the adhesive performs during the manufacturing process. The new preparation technique combined with standard fluorescence microscopy has provided a groundbreaking and accessible ability to understand how an adhesive responds to process changes in manufacturing. Improving the understanding of the dynamic relationship between the adhesive and manufacturing processes will be crucial in helping the wood products industry take advantage of the rapid improvements in processing technology.

Impact of sandpaper grit size on drag reduction and plastron stability of super-hydrophobic surface in turbulent flows

In this work, we experimentally investigated the impact of surface roughness on drag reduction as well as the plastron stability of superhydrophobic surfaces (SHSs) in turbulent flows. A series of SHSs were fabricated by spraying hydrophobic nanoparticles on sandpapers. By changing the grit size of sandpapers from 240 to 1500, the root mean square roughness height (krms) of the SHSs varied from 4 to 14 μm. The experiments were performed in a turbulent channel flow facility, where the mean flow speed (Um) varied from 0.5 to 4.4 m/s, and the Reynolds number (Rem) based on Um and channel height changed from 3400 to 26 400. The drag reduction by SHSs was measured based on pressure drops in the fully developed flow region. The plastron status and gas fraction (φg) were simultaneously monitored by reflected-light microscopy. Our results showed a strong correlation between drag reduction and krms+ = krms/δv, where δv is the viscous length scale. For krms+ < 1, drag reduction was independent of krms+. A maximum 47% drag reduction was observed. For 1 < krms+ < 2, less drag reduction was observed due to the roughness effect. And for krms+ > 2, the SHSs caused an increase in drag. Furthermore, we found that surface roughness influenced the trend of plastron depletion in turbulent flows. As increasing Rem, φg reduced gradually for SHSs with large krms, but reduced rapidly and maintained as a constant for SHSs with small krms. Finally, we found that as increasing Rem, the slip length of SHS reduced, although φg was nearly a constant.

The effect of abrading treatment method on the bonding surface characteristics and fracture behavior of glass fiber-epoxy composite adhesive joints

The effect of the mechanical abrading method on the bonding surface characteristics and fracture response of glass fiber-reinforced polymer (GFRP) composite adhesively bonded joints was investigated. Double cantilever beam specimens were manufactured by bonding GFRP substrates with an epoxy adhesive to evaluate the mode-I adhesive joint fracture response. The bonding surfaces were treated with degreasing and abrading methods utilizing sandpapers with various grit sizes ranging from P60 to P800. The results showed that the sandpaper grit size can considerably change the bonding surface properties comprising the surface energy, roughness, morphology, and water drop contact angle and consequently, it can affect the joint fracture behavior. Reducing the sandpaper grit size continuously increased the surface roughness but there were optimum values for the surface energy and water drop contact angle. The fracture resistance of adhesive joints followed the trend of bonding surface energy as the higher the bonding surface energy, the higher the joint fracture resistance. The fracture energy and load-bearing capacity of adhesive joints were improved by 62 and 34%, respectively, when the joint bonding surfaces were abraded with P240. However, further reducing the sandpaper grit size to P60 caused a decrease in the fracture energy and load-bearing capacity of adhesive joints by 18 and 44%, respectively, compared to the joint with degreased and non-abraded bonding surfaces. Moreover, the abrading method considerably changed the microscopic and macroscopic failure modes of adhesive joints.

Thermoforming of partially biodegradable hybrid thermoplastic composites for bone plate applications

This study introduces a partially biodegradable composite of carbon fibre/Nylon and Magnesium alloy (Mg) wire/polylactic acid (PLA) for bone fracture healing, focusing on its mechanical properties, with Young's modulus, flexural strength, and interlaminar shear strength investigated under different forming conditions. The Mg wires were subjected to mechanical and chemical treatments (with 80 and 220 grit sandpapers and phytic acid) to improve mechanical performance. Optimal treatment conditions were determined, and material test results were compared with microscopic observations. Using the recommended forming conditions, a hybrid composite bone plate was thermoformed for potential medical use.

Overcoming Tegumentary Numbness in Seeds of Crotalaria spectabilis and Crotalaria paulinea

Objective: To evaluate the efficiency of dormancy breaking methods in seeds of C. paulinea and C. Spectabilis. Theoretical reference: Species of crotalaria, such as C. paulinea and C. spectabilis, found in the Brazilian territory, are used as green manure in large crops and vegetable productions. However, the presence of tegumentary hardness in their seeds can result in failures in soil cover, which favor the emergence of weeds. Method/design/approach: The research was carried out at the Laboratório de Análise de Sementes of the Departamento de Agronomia, at the Universidade Federal de Viçosa, Minas Gerais. Twenty treatments were applied to the seeds to break dormancy, using mechanical scarification with 120 grit sandpaper, hot water in an oven at 90 °C for five and seven minutes, and immersion in sodium hypochlorite at four concentrations, 2%, 4%, 6% and 8%, for four times, two, four, six and eight hours. Results and conclusion: The most efficient treatments for breaking this dormancy in both species of crotalaria were scarification with sandpaper and immersion in water at 90±3 °C for seven minutes. Treatments using sodium hypochlorite were not effective in reducing the number of hard seeds. Originality/value: Feasibility of the methods applied to break dormancy in seeds of C. paulinea and C. Spectabilis, since they are used for green manure, and control of Aedes aegypti, among other purposes.

Integrated design of a robust superhydrophobic cement mortar layer via sizing sand grains

This work reported a facile route for fabricating super-hydrophobic concrete via sizing sand grains. It was found that mixing the sands with a size ranging from 150–180 μm into cement enabled the formation of a lotus-like surface with a papillary structure at micro-scale. SEM showed that the size of bumper was about 3 μm. When spraying a fluorocarbon solution onto this surface, the porous nature of the cement matrix showed the advantage of taking the fluorocarbon into the internal structure of the concrete via capillary force. As a result, the sub surface up to a depth of ∼1.5 mm were transformed into a thick superhydrophobic layer directly. The contact angle (CA) of water droplets could reach 157° on this surface, and which could remain more than 150° after abrasion 100 cycles under a weight of 300 g at 360 grit sandpaper. This thick hydrophobic layer significantly reduced the corrosion rate of the steel the concrete at the Cl- environment by 620 times. The measurement of British pendulum number and compression strength revealed that this superhydrophobic layer was beneficial for maintaining the friction coefficient of the concrete surface in wet condition without altering the mechanical integrity of the concrete.

Nickel plating on wood and wood composite surfaces: Characterization of surface durability

In this study, the performance of nickel plating on wooden surfaces was investigated. Black pine (BP), medium density fiber board (MDF) and particle board (PB) were used for the wooden samples. After the sample surfaces were sanded with 200, 500 and 1000 grit sandpaper and varnished with polyurethane varnish (150 g/m2), they were nickel plated using a spray gun and compressed air. After drying the samples at room temperature for 72 h, scratch analyses were performed according to TS EN 15186 (2012) and TS EN ISO 2409 (2020) and abrasion analyses were performed according to TS EN 13329 +A. The staining resistance of the samples was determined according to the DIN 53799 standard. According to the results, surface strength of the MDF samples was lower than those of PB and BP. The scratch analysis results for the black nickel coating were lower than those for TS EN 15186 (2012). However, it was higher according to TS EN ISO 2409 (2020) scratch analysis. In terms of stain resistance, all samples were found to be resistant to water, soap, tea, and acetone stains, except for coffee stains. Upon visual examination, a slight coffee stain was observed on the sample surfaces. As a result, in the light of surface strength analysis, it was concluded that the surfaces of wooden boards are not suitable for nickel plating.

The Effect of Surface Texture on Teflon as Electrification Layer of 360° Lateral-Sliding Mode Triboelectric Generator

Harvesting neglected mechanical energy from daily activities and converting it into electrical energy is a crucial start towards clean, low-cost, and sustainable energy. In this work, we report a development of a Teflon-based rotating triboelectric generator (TEG) and its relationship with rotational speed. The texture on Teflon was modified by uni-directionally rubbing the sandpaper with three different grit numbers; 500, 1000, and 1500 respectively, 50 times each. The surface roughness of the Teflon was measured using Mitutoyo Surface Roughness Machine SJ-310 before and after undergoing the 360° lateral sliding mode TEG test. The highest surface roughness was from 500 grit sandpaper, forming a Ra of 1.550 µm. Moreover, this surface of Teflon generated the highest output voltage of 25.3 mV at 1500 rpm with a calculated power density of 0.37 mW/m2. This simple technique gives an overview of how the surface texture may improve the electrical output of TEG by integrating the electrification contact area of TEG.

Synthesis of superhydrophobic FAS-EP/PTFE coating with excellent drag reduction performance and mechanical robustness

Superhydrophobic (SHP) materials have great potential for applications in self-cleaning, anti-fouling, anti-corrosion and drag reduction, but their poor mechanical robustness is a fundamental problem that hinders their practical application. In this work, we successfully and rapidly prepared SHP coating with good durability and drag reduction properties by a simple drop-coating technique after chemical modification and physical mixing. We investigated the effects of modification with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane (FAS-17), a low surface free energy material, and the filling content of Poly tetra fluoroethylene (PTFE) on the hydrophobic property of the as-prepared coating. The maximum water contact angle (WCA) and the minimum sliding angle (SA) of the coating were 160.2 ± 0.4° and 5°, respectively. The coating maintained superhydrophobicity after 4.4 m of abrasion with 400 grit sandpaper and 3 h of water impact, indicating its excellent mechanical durability. In addition, it has outstanding self-cleaning and self-repairing properties. Moreover, the coating was innovatively applied to the surface of the chute, because it remarkably reduced the adhesion between the wet foam block and the chute. These findings here provide a novel insight into the design of a robust SHP coating and suggest a new potential application in express sorting industry for drag reduction.

Effects of the Surface Roughness of Six Wood Species for Furniture Production on the Wettability and Bonding Quality of Coating

Wood surface roughness, surface free energy (SFE), wettability, and bonding quality for water-based acrylic coatings were investigated. The samples tested in this study included Pinus radiata, Pinus sylvestris, Larch, Hemp oak, Catalpa tree, and Camphor. Sandpaper with grits of 180, 240, 320, 400, and 500 was utilized to sand wood surfaces. The van OSS-Chaudhury-Good equation (vOCG) was used to calculate the SFE values. The modified model (M-D) was used to calculate the wettability based on the contact angle change rate (K value). The higher the K value, the faster the contact angle approaches equilibrium. A cross-cut test was used to evaluate the coating’s bonding quality. The anatomical structure of wood has an impact on the roughness of hardwood. The equilibrium contact angle is influenced by the wood species and sandpaper grit size. Sanding can make the surface of wood more wettable. Radiata pine that had been sanded to 180 grit had the highest SFE value. After finishing with waterborne acrylic, hardwood had a slightly better coating adhesion than softwood. Hemp oak wood had the lowest coating adhesion (0.6) and the highest K value (0.82). The best bonding quality (0.4) was supplied by the camphor wood with the lowest K value (0.13). Wettability in terms of K values was a good indication of determining the bonding quality of the water-based acrylic coatings.

Polymer-Metal Adhesion of Single-Lap Joints Using Fused Filament Fabrication Process: Aluminium with Carbon Fiber Reinforced Polyamide

Additive manufacturing (AM) is often used for prototyping; however, in recent years, there have been several final product applications, namely the development of polymer-metal hybrid (PMH) components that have emerged. In this paper, the objective is to characterize the adhesion of single-lap joints between two different materials: aluminium and a polymer-based material manufactured by fused filament fabrication (FFF). Single-lap joints were fabricated using an aluminium substrate with different surface treatments: sandpaper polishing (SP) and grit blasting (GB). Three filaments for FFF were tested: acrylonitrile butadiene styrene (ABS), polyamide (PA), and polyamide reinforced with short carbon fibers (PA + CF). To characterize the behaviour of these single-lap joints, mechanical tension loading tests were performed. The analysis of the fractured surface of the joints aimed to correlate the adhesion performance of each joint with the occurred failure mode. The obtained results show the impact of surface roughness (0.16 < Ra < 1.65 µm) on the mechanical properties of the PMH joint. The ultimate lap shear strength (ULSS) of PMH single-lap joints produced by FFF (1 < ULSS < 6.6 MPa) agree with the reported values in the literature and increases for substrates with a higher surface roughness, remelting of the primer (PA and PA + CF), and higher stiffness of the polymer-based adherent.

Tuning PVDF Membrane Porosity and Wettability Resistance via Varying Substrate Morphology for the Desalination of Highly Saline Water.

Here, we report the fabrication of a series of highly efficient polyvinylidene fluoride (PVDF) membranes via substrate morphology variations. A wide range of sandpaper grit sizes (150-1200) were utilized as casting substrates. The effect of the penetration of abrasive particles present on the sandpapers on the casted polymer solution was tuned, and the impact of these particles on porosity, surface wettability, liquid entry pressure and morphology were investigated. The membrane distillation performance of the developed membrane on sandpapers was evaluated for the desalination of highly saline water (70,000 ppm). Interestingly, the utilization of cheap and widely available sandpapers as a substrate for casting can not only help in tuning the MD performance, but also in producing highly efficient membranes with stable salt rejection (up to 100%) and a 210% increase in the permeate flux over 24 h. The findings in this study will help in delineating the role of substrate nature in controlling the produced membrane characteristics and performance.

Facile fabrication of flexible superhydrophobic surfaces with high durability and good mechanical strength through embedding silica nanoparticle into polymer substrate by spraying method

Flexible superhydrophobic surfaces have been attracting more and more attention due to their foldable property. However, the superhydrophobic structure was easily damaged or destroyed owing to their poor interfacial force between substrate and superhydrophobic coating. Herein, fluorinated silica nanoparticles (F-SiO2) were sprayed onto the wet poly(amide–imide) (PAI) surface, which made F-SiO2 easily went into PAI substrate to enhance the durability of superhydrophobic surface. The PAI/F-SiO2 flexible surface exhibited a water contact angle (CA) of beyond 160° and a sliding angle (SA) of as low as 3°, while the tensile strength (34 MPa) was comparable to that of PAI substrate (35.8 MPa). Encouragingly, the superhydrophobicity and hierarchical porous structure of PAI/F-SiO2 surface were maintained even they were folded by 5000 times or underwent sandpaper abrasion test (500 cm of wear on a 1200 grit sandpaper under 50 g load), while the nanocomposites failed the sandpaper abrasion test when F-SiO2 were sprayed onto completely dried PAI surface. More importantly, the CA and SA just slightly decreased when PAI/F-SiO2 surfaces were heated at 300 °C for 24 h due to the unique surface morphology and high thermal stability of PAI, which is one of the highest thermal stabilities for flexible superhydrophobic films. In addition, PAI/F-SiO2 surfaces maintained superhydrophobic after hot water jet impact, acid–base immersing, UV irradiation, and ultrasonic treatment, indicating the fabricated surfaces could be used for practical application especially under harsh conditions. Furthermore, the superhydrophobic surfaces possessed icephobic properties. It should be noted that PAI/F-SiO2 surfaces showed such excellent properties, although their fabricating procedure did not undergo any optimization. This wet spraying method was also used to fabricate flexible superhydrophobic surfaces with other polymers as substrates such as poly(acrylic acid) (PAA), thermoplastic polyurethane (TPU), polystyrene (PS), and poly(vinyl alcohol) (PVA). Therefore, the simple strategy provided a general route to prepare flexible superhydrophobic films with high durability.

Experimental research on the polished surface quality of hard anodized film of aluminum alloy

An experimental study was conducted for the surface polishing of the oxide film after hard anodizing of 2D70 aluminum alloy. The surface roughness and surface morphology of aluminum alloy before, after anodizing and after polishing were analyzed, and the effects of polishing force, polishing speed, feeding amount and sandpaper grit on the polished surface roughness were investigated experimentally. The results showed that the surface roughness of 2D70 aluminum alloy decreased by 1 grade on average after hard anodizing. The hard anodized film surface has more linear protrusions, large pits and a large number of small pores. After polishing, the linear protrusions and small pores disappear, and a small number of new linear grooves appear, while the condition of large pits does not change much. The depth of small pores on the oxide film surface is within 11μm in most cases. As the polishing force, feeding amount and sandpaper grit increase, the decreasing trend of roughness value also gradually increases, and the decreasing trend of the thickness of hard anodic oxide film gradually increases. As the polishing speed increases, there is no clear trend in the decreasing trend of rough