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A large amount of stabilized municipal solid waste (SMSW) obtained in landfill mining operations constitutes about 60–70% of total mining waste. In this study, attempts were made to use SMSW in paver block construction, a unique solution for unpaved urban surfaces considering its ease of handling and low cost. The mechanical and durability properties of the paver block, along with microstructure and mineralogical analysis, were investigated in which various dosages of SMSW vary from 10–50% by the weight of natural sand. The results of various tests, i.e., compressive, flexural strength, abrasion resistance, water absorption, and analysis of microstructure and mineralogical, revealed that SMSW as a partial replacement of natural sand up to 30% replacement could be satisfactorily used in the paver block construction, especially in the low volume roads. Also, the replacements, 40% and 50%, can be used for footpaths, cycle paths, garden parks, domestic drives, and embankment slopes. The geometrical properties and visual aspects were checked to confirm the production standardization of the paver blocks. All the samples have shown promising results in respect of all dimensions. The statistical analysis exhibited that the SMSW had a significant effect on the compressive and flexural strength of the paver block. Therefore, incorporating SMSW as a natural sand replacement will be a sustainable and economical construction solution for light-traffic roads. It also promotes a 'Circular economy' as it recycles the stabilized municipal solid waste. [ABSTRACT FROM AUTHOR]

Hand scrubbing is an absolute precaution to avoid surgical site infections. World Health Organization (WHO) recommends 4-min overall scrubbing (4MS) for surgical hand hygiene. However, we hypothesize that the more methodical 10-stroke counting technique (10SS) via locational partitioning of the arm is superior to WHO's superficial guideline dictating only the duration. The mechanical efficiency of 4MS and 10SS techniques are compared. 24 healthcare professionals were recruited for the study. A novel methodology was devised to quantify the average brightness change of skin-applied UV ink before and after scrubbing via pixel intensity analysis. A black-box setup is constructed with an integrated high-resolution camera to photograph the UV-stained dorsal arm. Each stain was then digitally isolated for brightness comparison. It was observed that the 10SS technique was overall more successful in removing the UV ink in comparison to the 4MS method (p = 0.014). In addition, a bias was observed in removing more percentage of the proximal stains when compared to middle and distal stains with the 4MS technique (p = 0.0027), while location-based brightness change averages were statistically equal with the 10SS technique (p = 0.423). 10SS provided not only a more mechanically efficient scrubbing but also a more homogenous cleaning than 4MS. We recommend the use of the 10SS technique to achieve more effective pre-surgical hand hygiene. • The mechanical efficiency of 4-Minute-Scrub and 10-Stroke-Scrub were compared. • The abrasion efficacy was evaluated through a pixel intensity comparison methodology. • 10SS was overall more successful in removing the UV ink compared to the 4MS method. • 10SS provided more mechanically efficient and homogenous cleaning than 4MS. [ABSTRACT FROM AUTHOR]

Enamel coating has potential application in steel rebar protection due to its high durability, excellent corrosion resistance, and strong coating/concrete interface bond. The newly developed low temperature enamel (LTE) coating has a substantially lower sintering temperature than that of traditional enamel coatings, whereas its adhesion mechanism to the substrate is expected to vary dramatically. In this study, abrasives of various particle sizes were used to blast steel substrates to create various surface states, to investigate the influence of substrate surface roughening on the interfacial properties of LTE coating. The surface roughness of substrates was quantitatively characterized by a 3D optical profiler. The adhesion, impact resistance, and abrasion resistance of LTE coating under different substrate surface states were investigated by pull-off, falling weight impact, and Taber abrasion test, respectively. The results showed that with increasing substrate surface roughness, the adhesion strength and impact resistance of the LTE coating were greatly improved. Within the investigated range, the substrate surface roughness had negligible influence on abrasion resistance. Overall, appropriate substrate surface roughening can provide the LTE coating with sufficient interface adhesion, impact resistance, and abrasion resistance. [ABSTRACT FROM AUTHOR]

Lunar regolith degrades human health and equipment making mitigation paramount for lunar missions. Cryogenic liquid sprays are a recently developed, simple, and convenient concept for dust mitigation in a lunar environment. However, removal efficacy and material degradation under the extreme cryogenic vacuum environment are unknown. Traditional space suit dust mitigation technologies used on the Apollo missions, such as brushing and vacuuming, introduced suit fabric abrasion which must be addressed for all dust mitigation methods considered for lunar implementation. This publication reports the efficacy of dust removal in a simulated airlock vacuum environment and the associated impact of repeated dusting-washing cycles on spacesuit materials. Specimens were impinged with measured liquid nitrogen sprays at different spray angles within a vacuum chamber. Mean mass removal of 98.4% was achieved in a vacuum environment at optimal conditions, correlating to 95.9% removal of particles below 10 μm. To investigate material degradation, a total of 26 samples were cycled a cumulative 233 times through cryogen spray washings under ambient conditions. A degradation scale was created to classify optical microscopy observations. Degradation results indicate minimal spacesuit material abrasion from liquid nitrogen removal. Results additionally show an average of 2.66% increased removal with each subsequent washing cycle for fabric washed twice, possibly due to clogging and occupancy of specific sites. The conclusion is that liquid nitrogen sprays cause relatively less damage than conventional dust mitigation techniques, even under the extremes of cryogenic temperatures and vacuum. • Liquid nitrogen sprays demonstrate up to 98.4% simulant removal in a vacuum environment. • Liquid nitrogen sprays introduce less degradation than alternative lunar dust mitigation techniques after 75 cycles. • Mass fraction removal of lunar dust by liquid nitrogen sprays increases on subsequent washes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Abrasion resistance improvement of antireflective coating on glass by applying hidrophobic antisoiling coating. • Analysis of two different abrasion tests (linear Taber test and oscillating sand test) on antisoiling and antireflective coatings on solar glass covers. • Different degradation mechanisms identified according to the abrasive sand used in the oscillating sand test. • Complete optical characterization together with profilometric and microscope analyses necessary to study abrasion resistance in solar glass covers. The abrasion resistance of the antireflective coatings (ARC) applied on both sides of the parabolic-trough glass tubes is a key point to maintain throughout time the enhanced efficiency which produces the use of this film. The cleaning processes as well as the erosion produced by dust or sand in desert environments can damage the ARC, even removing it, affecting the system efficiency. The use of an antisoiling (AS) treatment on the antireflective (AR) coated solar glass envelopes are reaching increasing interest to reduce soiling and the water consumption associated to cleaning. RIOGLASS AR coated tubular samples were coated with a commercial hydrophobic treatment and the abrasion resistance of the AR + AS coatings combination against sole ARC were studied by carrying out two abrasion tests. Initial average solar transmittance values of 96.9 % and initial average static contact angle of 107° were obtained for the AR + AS samples. The results from the two abrasion tests have shown that the AR + AS coatings combination present a higher resistance to the abrasion. It has also been observed that two different abrasive media in the sand oscillating test produce different degradation mechanisms, (reflection losses versus absorptance losses). Additionally, the results have shown that solar transmittance values are not enough to characterize the abrasion degradation of AR coatings, being also important the haze value. Similar solar transmittance values (93.9 % and 94 %) but with different haze values (1.2 % against 3.2 %) and very different transmittance spectra indicating distinct degradation mechanism were obtained for samples abraded with two different sands. [ABSTRACT FROM AUTHOR]

This in vitro investigation assessed how frequency of erosive challenges and duration of toothbrushing abrasion influenced non-carious cervical lesions (NCCLs) development and morphology. Design: Experimental units were prepared using extracted human premolars assigned to four erosive-abrasive frequency protocols (n=16): F0. No acid exposure (negative control), F2.5 K. Acid exposure (1 % citric acid at natural pH) every 2500, F5K. 5000 and F15K. 15000 brushing-strokes. All groups were brushed for 55000 total brushing-strokes. Three-dimension images of the teeth were captured at baseline, after 15000, 35000 and 55000 brushing-strokes, using an intraoral scanner (TRIOS4, 3Shape). WearCompare software (Leeds Digital Dentistry) was used to analyze volumetric tooth loss (mm3) by superimposition followed by subtraction analysis. Lesion angle was measured (ImageJ, NIH) and morphology visually classified. Data were analyzed using ANOVA and Fisher's Exact tests adopting two-sided 5 % significance level. Results: Tooth loss increased with brushing-strokes overall (p<0.001) and for each erosive-abrasive protocol (p<0.001). Acid exposure significantly increased tooth loss (p<0.001), regardless of brushing interval (p<0.001), however by 35000 strokes no tooth loss difference was observed among acid-exposed groups (p>0.05). Control had significantly sharper mean lesion angle (59°) than all acid-exposed groups (∼145°) (p<0.001), and significantly different lesion shape with 94 % wedge-shaped lesions versus 0 %, respectively (p<0.001). In contrast to the control, acid exposure was associated to more striated lesions. Conclusions: Simulated NCCLs developed and progressed differently and more rapidly in the presence of acidic challenges, regardless of their frequency. Exposure to acid impacted the morphology of lesions. • Exposure to acid challenges significantly increase development of NCCLs. • Frequency of erosion and abrasion impacts NCCLs development and morphology. • NCCLs etiological factors and morphology can aid in early diagnosis and management. [ABSTRACT FROM AUTHOR]

Solar energy capture and storage using falling solid particles are being explored for cost-effective next generation concentrating solar power systems. A critical consideration in this technology is the abrasion wear caused by the sliding of the particles under varying speed and pressure over component surfaces. This study presents computational modeling of a subsystem comprising a particle storage bin discharging through a flow control valve that is prone to abrasive wear. The effects of several geometric parameters are systematically evaluated for their impact on spatial and temporal abrasion rates in the storage bin, the control valve, and the valve housing. The findings provide insights into the locations most susceptible to abrasion, and the use of targeted abrasion mitigation coatings is illustrated. [ABSTRACT FROM AUTHOR]

The addition of powdered activated carbon (PAC) has been widely accepted as a solution to alleviate membrane fouling and maintain a sustainable flux in membrane bioreactor (MBR) and anaerobic membrane bioreactor (AnMBR). This is due to PAC's unique characteristics, such as serving as a supportive medium for bacterial attachment and growth, achieving adsorption of organic foulants and providing abrasion effect that minimizes the formation of cake layers on membrane surfaces. While majority of ultrafiltration (UF) membranes used in MBR and AnMBR application are polymeric, no study has yet investigated the integrity of polymeric UF membranes with the addition of PAC adsorbents. The abrasive effects of PAC on membrane surfaces under gas sparging in AnMBR or air scouring in MBR have not been studied, and no guidelines have been established for selecting a reliable PAC for such purposes. To address these concerns, this study systemically investigated the integrity of polymeric UF membranes with five different types of PACs to establish recommendations for PAC selection. Based on the integrity testing of polymeric UF membranes, a recommendation for PAC selection was formulated, highlighting bulk density and Gold Number (GN) as pivotal criteria. Five distinct types of PACs were studied to determine the optimal characteristics for polymeric UF membranes, considering variations in raw materials (coal-based and wood-based), activation methods (chemical and steam), particle morphology (sharp and granular), bulk densities (ranging from 0.23 to 0.6 kg/L) and GNs (spanning from 0.1 to > 6.0). The investigation extended beyond 100 d or until irreversible defects were observed in the UF membranes. This study provides guidelines for selecting PACs to be used with polymeric UF membranes, aiming to improve membrane performance while minimising their impact on membrane surfaces. [Display omitted] • Bulk density (kg/L) and Gold Number (GN) are key characteristics on PAC selection. • Abrasion of polymeric UF membrane depends on raw material and activation method of PAC. • Coal-based & steam-activated PAC to be ≤ 0.35 kg/L and ≤ GN 6.0, regardless of MLSS. • Wood-based & chemical-activated PAC to be ≤ 0.35 kg/L and ≤ GN 1.0 with MLSS. • Wood-based & chemical-activated PAC to be ≤ 0.35 kg/L and ≤ GN 0.1 without MLSS. [ABSTRACT FROM AUTHOR]

The present study investigates the tribological properties of a newly developed multicomponent aluminium weight-light multicomponent alloy for wear based on the Al80Mg10Si5Cu5 system for lightweight automotive applications, especially back drum discs. The samples were manufactured by High-Pressure Die Casting (HPDC) employing cast alloy returns and secondary aluminium ingots and were tested at room temperature (RT) and 200 °C. It has been observed that the Al80Mg10Si5Cu5 alloy offers a higher hardness and wear resistance at RT and especially at 200 °C compared with the AlSi9Cu3 reference alloy (x10 times reduction in wear rate). The impact of maintaining the external surface layer (skin) of HPDC cast parts has been studied for the ball-on disc test, showing improved tribological properties and the possibility of avoiding the machining of contact surfaces. The as-cast Al80Mg10Si5Cu alloy with the surface layer showed a wear rate coefficient of 5 × 10−4 mm3/N.m2 at RT, a 50 % lower than that of the sample without skin. Solution heat-treated samples (72 h at 440 °C, water quenching at 75 °C, and natural aging) with the surface layer showed a wear rate coefficient of 11 × 10−4 mm3/N.m2, approximately 20 % lower than the sample without a surface layer. The wear rate of AlSi9Cu3 alloy decreased by more than 50 % in the samples without skin at RT. At 200 °C, wear rate coefficients were lower in the samples with the surface layer. • Investigation of the tribological properties of a newly developed Al80Mg10Si5Cu5 alloy for wear at high temperatures. • Increased ×10 times the wear resistance of AlSi9Cu3 alloy at 200 °C. • A new study on the effect of cast surface over the wear properties at room temperature and at 200 °C. • The surface of cast parts can increase the resistance to wear by 50 %. [ABSTRACT FROM AUTHOR]

The outstanding strength-to-weight ratio and corrosion resistance of titanium have made it the material of choice in the aerospace industry and medicine. The alpha–beta alloy Ti6Al4V is particularly preferred for its excellent mechanical and bio-compatible properties. Despite its advantages, the low thermal conductivity and poor tribological performance of titanium pose significant challenges during manufacturing and in operation. This research offers deep insights into the high strain rate behavior of Ti6Al4V under abrasive load, such as e.g. experienced in machining, by modifying the standard scratch test setup and using optimized Johnson–Cook material parameters to perform Material Point Method (MPM) simulations. The MPM simulations provide accurate predictions of the data gathered through high strain rate scratch experiments. We found an increase in the von Mises stress distribution as well as the normal and tangential forces required to perform a scratch of the same depth as the strain rate increases. The morphology of the scratch profiles also showed an increase in the height of the ridges that form as the scratching speed increases. These findings are in line with the increase in yield strength and work hardening with growing strain rate. This study bridges the gap between simulation models and experimental observations by providing insights for improved machining strategies and surface treatments that can enhance the performance of Ti6Al4V in demanding applications. • High velocity scratches performed at comparable speeds as abrasive events. • The scratches performed at 6.5 m/s close the gap with meshless simulations. • Meshless simulations capture the effects entailed by high strain rates. • These insights will aid better machining and abrasion simulations of Ti6Al4V. [ABSTRACT FROM AUTHOR]

Superhydrophobicity being a widely-used characteristic in functional materials that has attracted much interests in academic and industrial applications, such as self-cleaning, anti-corrosion, anti-drag, and anti-icing. Until now, the durability of superhydrophobicity is still a big challenge to limit its extensive applications. Method: Here, we develop a fully superhydrophobic strategy with super durability in a porous medium. The porous medium is achieved as a fully superhydrophobic bulk by treating with the 1 H,1 H,2 H,2 H-PerfluorodecyltriMethoxysilane (FAS-17) at 95 °C. Due to the capillary effect, the FAS-17 liquid readily flows to the whole of the porous medium to modify all surface for superhydrophobicity. Significant Findings: Evaluated via various treatments, including sanding 30 times, repeated exposure at −20 °C to 350 °C 100 times, and immersing in solutions of pH from 3 to 12, the superhydrophobic surface maintains a stabilized contact angle with a slight change. Additionally, this strategy would be a general method which is applicable to many porous media, including Co 3 O 4 , CeO 2 , Fe 2 O 3 , MnO 2 , CuO, and MgO. This work shows the great potential of the fully superhydrophobic porous medium to provide a simple way to design superhydrophobic materials with super durability and facilitates valid avenues for functional surface designing. [Display omitted] • A fully hydrophobic strategy with super durability in a porous medium is proposed. • The prepared hydrophobic bulk has multiple hydrophobic surfaces and excellent mechanical properties. • The hydrophobic bulk can maintain a stable contact angle even under extreme conditions. • This strategy is a universal method applicable to broad ranges of porous media. [ABSTRACT FROM AUTHOR]

Fly ash (FA), a hazardous byproduct of coal combustion in power plants, poses significant environmental and health risks due to improper disposal and utilization. This study introduces a facile, sustainable, and cost-effective method for converting FA into a robust superhydrophobic material for various substrates. -FA particles are modified with polydopamine (PD) in water and covalently grafted with octadecylamine (ODA) via the Michael Addition-Schiff Base reactions, resulting in robust superhydrophobic FA (SH-FA) with a water contact angle (WCA) of 163° (±3.1). When applied as a coating to jute, cotton, polyester fibers, PU sponge, and wood, they became superhydrophobic, with WCAs ranging from 154.7 to 161.2° except for the wood substrate, which achieved a WCA of 132° (±3°). The coated polyester fabric exhibited remarkable durability, retaining consistent WCA values after 70 abrasion cycles, 75 adhesive tape peelings, and 20 detergent washing cycles. It also showcased excellent self-cleaning properties, effectively repelling dust and various liquids. Additionally, the coated PU sponge demonstrated exceptional performance in separating oil from different oil/water mixtures, achieving rapid separation of organic solvents within seconds and maintaining a separation efficiency of over 98% even after 12 reuse cycles. These results indicate the potential for transforming FA through effective management. Sustainable transformation of fly ash into multifunctional durable superhydrophobic coatings. [Display omitted] • Fly ash was upcycled into a superhydrophobic coating. • Fly ash was treated with polydopamine and octadecylamine in water/alcohol. • The modified fly ash displayed a water contact angle of 163° (±3.1°). • The fly ash coating performed exceptionally well on fabrics, wood, and sponges. • The coating exhibited high durability and stability. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the in situ/in vivo effect of quercetin on dentin erosion and abrasion. Human dentin blocks (2 × 2 × 2 mm) were embedded and assigned to 6 groups: 75 μg/mL, 150 μg/mL and 300 μg/mL quercetin (Q75, Q150, Q300); 120 μg/mL chlorhexidine (CHX, positive control); and deionized water and ethanol (the negative controls). The specimens were treated with the respective solutions for 2 min and then subjected to in situ /in vivo erosive/abrasive challenge for 7 d as follows: in vivo erosion 4 times a day and then in vivo toothbrush abrasion after the first and last erosive challenges of each day. Dentin loss was assessed by profilometry. An additional dentin specimen was used to evaluate the penetration depth of quercetin into dentin by tracking the spatial distribution of its characteristic Raman peak. Moreover, dentin blocks (7 × 1.7 × 0.7 mm) were used to detect the impact of quercetin on dentin-derived matrix metalloproteinase (MMP) inhibition by in situ zymography, and the inhibition percentage (%) was calculated. Additionally, the potential collagen crosslinking interactions with quercetin were detected by Raman spectroscopy, and the crosslinking degree was determined with a ninhydrin assay. Fully demineralized dentin beams (0.5 × 0.5 × 10 mm) were used to evaluate the impact of quercetin on the mechanical properties of dentin collagen fibre by the ultimate micro-tensile strength test (μUTS). The data were analysed by one-way analysis of variance and Tukey's test (α = 0.05). Compared to the negative controls, all treatment solutions significantly reduced dentin loss. The dentin loss of Q150 and Q300 was significantly less than that of CHX (all P < 0.05). The amount of quercetin decreased with increasing dentin depth, and the maximum penetration depth was approximately 25–30 µm. In situ zymography showed that quercetin significantly inhibited the activities of dentin-derived MMPs. The inhibitory percentages of Q75 and Q150 were significantly lower than that of CHX (all P < 0.05), but no significant difference was found between Q300 and CHX (P = 0.58). The collagen crosslinking interactions with quercetin primarily involved hydrogen bonding and the degree of crosslinking increased in a concentration-dependent manner. Statistically significant increases in μUTS values were observed for demineralized dentin beams after quercetin treatment compared with those of the control treatments (all P < 0.05). This study provides the first direct evidence that quercetin could penetrate approximately 25–30 µm into dentin and further prevent dentin erosion and abrasion by inhibiting dentin-derived MMP activity as well as crosslinking collagen of the demineralized organic matrix. [ABSTRACT FROM AUTHOR]

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression (25%), bending (90°), and torsion (26°/cm) equivalent to five life-years of severe limb flexions. Abrasion was assessed using an abrasion damage score (ADS, range 1–7) for each deformation mode. Misago produced the least abrasion and no stent fractures (ADS 3). Innova caused small abrasion under compression and torsion but large damage under bending (ADS 7). Supera performed well under bending and compression but caused damage under torsion (ADS 8). AbsolutePro produced significant abrasion under bending and compression but less damage under torsion (ADS 12). Zilver fractured under all three deformations and severely abraded the tube under bending and compression (ADS 15). SmartControl and SmartFlex fractured under all three deformations and produced significant abrasion due to strut penetration (ADS 20 and 21). ADS strongly correlated with clinical 12-month primary patency and target lesion revascularization rates, and the described method of assessing peripheral stent abrasiveness can guide device selection and development. Poor outcomes of peripheral arterial disease stenting are related to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our study presents the first attempt at assessing peripheral stent abrasiveness, and the proposed method is applied to compare the abrasion damage caused by Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera peripheral stents using artery-mimicking synthetic tubes and cyclic deformations equivalent to five life-years of severe limb flexions. The abrasion damage caused by stents strongly correlates with their clinical 12-month primary patency and target lesion revascularization rates, and the described methodology can be used as a cost-effective and controlled way of assessing stent performance, which can guide device selection and development. [Display omitted] [ABSTRACT FROM AUTHOR]

• FB-TGA long-term cycles reveal periodic abrasion/agglomeration behaviors. • OC fatigue fracture resulted in intermittent and extensive particle fragmentation. • OC agglomeration start at the FB-TGA bottom and accelerate upwards. • Intermittent contributions in mechanical, thermal, and chemical stress on abrasion. • The industrial assessment of abrasion and agglomeration of hematite and ilmenite OC. Abrasion and agglomeration characteristics of hematite and ilmenite oxygen carriers (OCs) were investigated over long-term redox cycles by fluidized bed thermogravimetric analysis. The concept of OC fatigue failure was introduced, characterized by abrupt and large-scale particle fragmentation during the moderate abrasion stage. A periodic abrasion pattern emerged, where each instance of fatigue failure temporarily exacerbated abrasion and intensified thermal and mechanical stresses. Chemical stress was identified as the predominant driver of OC attrition and fatigue failure, contributing to over 50% abrasion after 40 min redox and increasing to 90% by the 162th cycle. Agglomeration exhibited an accelerating deterioration trend, initiating at the reactor base and progressively extending upward. Hematite OC demonstrated high susceptibility to abrasion and fatigue failure, undergoing extensive particle fragmentation after 10 cycles, with attrition rate increasing from 1.8 wt.%/h to 16 wt.%/h. Ilmenite OC demonstrated remarkable resistance to abrasion and agglomeration, with an estimated lifetime of 3800 h and endurance of 1350 redox cycles before experiencing agglomeration-induced defluidization. Agglomeration was significantly exacerbated under deep reduction and fixed bed situations, leading to phase separation of Fe 2 TiO 5 , the emergence of fully molten surfaces, and formation of an iron-rich layer within 45 redox cycles. It is recommended to control the OC residence time within an optimal range to prevent excessive reduction and ensure efficient performance. A fundamental trade-off in OC performance was underscored, necessitating a balancing between oxygen transport capacity, reactivity and resistance to abrasion and agglomeration. [ABSTRACT FROM AUTHOR]

Ocean engineering components are subjected to intense corrosion and abrasion. To address these challenges, the Fe-based amorphous composite coating was engineered for compatibility with these harsh conditions. The Fe-based amorphous composite coating, incorporating TiN x , demonstrated improved nanomechanical properties, offering enhanced resistance against external forces. The integration of TiN x acted as a structural backbone, limiting crack propagation within the amorphous matrix. Although the corrosion resistance of this composite coating was slightly reduced, it demonstrated improved durability subjected to hydraulic machinery corrosion abrasion working condition. Notably, under conditions of higher tribological pair speeds and increased sand concentrations, this composite coating exhibited significantly lower weight loss increase and reduced wear rates escalation compared to coatings made entirely from Fe-based amorphous material. Moreover, the composite coating exhibited diminished susceptibility to erosion damage, with reduced size and severity of erosion craters. These underlying mechanisms are thoroughly discussed in the paper. • TiN x phase and Fe-based amorphous exhibit excellent bonding condition. • TiN x enhancing Fe-based amorphous coating possesses excellent nanomechanical properties. • Composite coating shows great corrosion-abrasion resistance statistically and morphologically. [ABSTRACT FROM AUTHOR]

Shoeprint reconstruction is essential in forensic science, but it is also challenging due to various inconsistencies in the patterns, textures, sizes, abrasions, etc. of shoeprints. The computational reconstruction of sharper and more complete shoeprints is conventionally conducted using handcrafted features, and it often requires human intervention. Prior studies using end-to-end machine learning approaches are limited in number and have not achieved a high level of performance. In this paper, we propose a model named ShoeRec, which employs variational autoencoder (VAE) as a component in a U-Net-like architecture to reconstruct missing regions and borders in shoeprint images. ShoeRec incorporates skip connections to preserve key patterns and employs VAE in the bottleneck to facilitate the reconstruction of desired shoeprints with the restoration of detail as perceived by humans. As a U-Net, the model skips the contextual information from the encoder to the decoder, and the compressed features in the latent space via VAE optimize the probabilistic distribution for reconstructing complete shoeprints. The reconstruction operation is automatically tuned according to the objective function, so as to reduce the structural correlation between the original and projected shoeprint and restore the absent information in the desired shoeprints. To the best of our knowledge, ShoeRec is the first deep learning infusion model that specializes in shoeprint reconstruction. The shoeprints reconstructed by ShoeRec have a close match with the originals in terms of both structures and patterns, and ShoeRec outperforms state-of-the-art generative models in human evaluation. • An end-to-end deep learning model focuses on shoeprint reconstruction for forensics. • Reconstruction of existing patterns together with the generation of missing regions. • Missing regions reconstruction is specifically designed based on the loss function. • The proposed model performs well for noisy, blurry, and partial input images. • Model outperforms state-of-the-art generative models in terms of human evaluation. [ABSTRACT FROM AUTHOR]

In this work, wear mechanisms of electrodeposited Ni–W and Ni–W/Al 2 O 3 coatings sliding against Si 3 N 4 and AISI 52100 steel have been comparatively studied. For both Ni–W and its composite coatings sliding against Si 3 N 4, worn morphology shows the tribochemical reaction (tribooxidation) followed by abrasive wear is the dominated mechanism. Comparing with Ni–W coatings, the protective oxide layer is slower peeled off at tribooxidation stage and wear debris are easier squeezed on the Ni–W/Al 2 O 3 during abrasive wear stage. The incorporated Al 2 O 3 provide load bearing effect during microploughing and improve the wear resistance. As sliding against AISI 52100 steel, wear rate of Ni–W/Al 2 O 3 is several times higher than that of Ni–W coatings. Conformity between surfaces of the Ni–W coating and counterbody leads to mild smoothening wear, while the plastic deformation dominated delamination makes severe wear of Ni–W/Al 2 O 3. Deformation resistance of the coatings and transition of counterbodies materials from ceramic to hard metal are responsible for the different wear mechanisms. For Si 3 N 4 ceramic, low thermal conductivity leads to tribooxidation followed by abrasive wear of both Ni–W and Ni–W/Al 2 O 3 coatings. Relatively high deformation resistance of Ni–W coatings is responsible for the conformity as the premise for mild wear sliding against AISI 52100. Low deformation resistance of composite coatings induced by weak interfaces between Al 2 O 3 and Ni–W matrix makes delamination sustained. • Effect of counterbodies on wear behavior of Ni–W and Ni–W/Al 2 O 3 coatings is revealed. • Against Si 3 N 4 or AISI 52100, Ni-W/Al 2 O 3 has better or much worse anti-wear than Ni-W. • Wear mechanism of Ni–W and Ni–W/Al 2 O 3 vs. Si 3 N 4 is tribooxidation followed abrasion. • Ni–W and Ni–W/Al 2 O 3 vs. AISI 52100 exhibit mild smoothening and severe delamination. • Deformation resistance of coatings are responsible for wear mechanisms. [ABSTRACT FROM AUTHOR]

This study investigates the microstructural characteristics, mechanical properties, and slurry abrasion resistance of WC-10Co-4Cr and WC-10Co-4Cr + GNPs coatings deposited using the High-Velocity Oxy-Fuel (HVOF) process. Cross-sectional micrographs, EDS line scans, and spectra reveal uniform distribution and proper adhesion of tungsten carbide particles, cobalt, chromium, and graphene nanoplatelets (GNPs) throughout the WC-10Co-4Cr + GNPs coating. Microstructural analysis indicates denser structure and reduced porosity in the WC-10Co-4Cr + GNPs coating, leading to enhanced abrasion resistance. Mechanical testing demonstrates higher microhardness and bond strength in the WC-10Co-4Cr + GNPs coating, attributed to the incorporation of GNPs and Laser Surface Texturing (LST). Slurry abrasion tests show substantial reductions in mass loss for both coatings compared to the pristine substrate, with the WC-10Co-4Cr + GNPs coating exhibiting superior performance due to its densification and lubrication effect of GNPs. Overall, the WC-10Co-4Cr + GNPs coating presents a promising solution for applications requiring high wear resistance and durability in harsh environments. [Display omitted] • WC-10Co-4Cr + GNPs coatings exhibit superior wear resistance and mechanical properties. • Addition of GNPs results in a denser coating structure with reduced porosity. • Laser surface texturing enhances the bond strength of WC-10Co-4Cr + GNPs coatings. • This reported coating is best-suitable for practical application. [ABSTRACT FROM AUTHOR]

The abrasive behavior of M 2 AlX MAX phase materials (Ti 2 AlC, Cr 2 AlC, Ti 2 AlN) was investigated using sandblasting tests with glass beads and alumina particles. Interpretations are based on the specimens' morphologies before and after the sandblasting tests. Overall, the abrasive behavior appears to be related to the brittleness index B , which is a function of the hardness, elastic modulus and fracture toughness. An extension of the analysis to literature data for different hardened and unhardened glasses indicated that this qualitative evaluation factor B can support in the prediction of the abrasive behavior of a wider range of brittle materials. [ABSTRACT FROM AUTHOR]

To evaluate two-body wear (2BW) and three-body wear (3BW) of different CAD/CAM and direct restorative materials against zirconia using a dual-axis chewing simulator and an ACTA wear machine. 3 CAD-CAM resin-based composite or polymer infiltrated ceramic network blocs, 1 lithium disilicate CAD-CAM ceramic (LS 2), 3 direct resin composites, amalgam and bovine enamel were tested. For 2BW, 8 flat specimens per material were produced, grinded, polished, stored wet (37 °C, 28d) and tested (49 N, 37 °C, 1,200,000 cycles) against zirconia. For 3BW, specimens (n = 10) were stored accordingly, and tested against a zirconia antagonist wheel (3Y-TZP, d = 20 mm, h = 6 mm; 200,000 cycles, F = 15 N, f = 1 Hz, 15% slip) in millet seed suspension. Wear resistance was analysed in a 3D optical non-contact profilometer, measuring vertical wear depth and volume loss for 2BW and mean wear depth and roughness (R a) for 3BW. Vickers hardness (15 s, HV2) was measured. Statistical analysis was performed using non-parametric tests (Mann-Whitney-U test, p < 0.05). 2BW and 3BW have a different impact on material surfaces. Similar wear resistance was observed for direct and indirect resin based materials with analogous filler configurations in both methods. Bovine enamel exhibited the best wear resistance in 2BW, but the least wear resistance in 3BW against zirconia. Regarding 2BW, a direct/indirect composite material pair of the same manufacturer showed the significantly highest mean volume losses (2.72/2.85 mm³), followed by LS 2 (1.41 mm³). LS 2 presented the best wear resistance in 3BW (mean wear depth 2.85 µm), combined with the highest mean Vickers hardness (598 MPa). No linear correlation was found between Vickers hardness and both wear testing procedures. The zirconia antagonists showed no recordable signs of wear. Dental restorative materials behave differently in 2BW and 3BW laboratory testing. Vickers hardness testing alone cannot hold for a correlation with wear behavior of materials. Micromorphological investigation of material composition can reveal insights in wear mechanisms related to variations in filler technologies. • Materials respond differently under two- and three-body wear loading conditions. • Surface hardness is no general predictor of wear resistance of dental materials. • Wear of resin-based composites is mainly influenced by filler configuration. • Polished zirconia creates substantial antagonist wear on various dental materials. [ABSTRACT FROM AUTHOR]

As PV cleaning machines become widely adopted in desert regions, there is concern that frequent dry-brushing might abrade modules' anti-reflective coating (ARC). It is common to study ARC abrasion via accelerated lab tests, which typically differ from real-world PV cleaning regarding sample format, test conditions and characterization tools. This paper reviews research on PV ARC cleaning abrasion, focusing on differences in experimental techniques between the lab and field. The main conclusions are: (1) coupon tests should be verified with full-size modules due to dependence of coating properties on sample size, (2) lab tests should be verified outdoors with non-accelerated cleaning schedules because abrasion is largely caused by the soiling layer itself when brushing, (3) reflectivity is well suited to measuring ARC abrasion because it can be performed in the field and is reasonably consistent with module optical performance, (4) different ARCs exhibit a wide range of abrasion susceptibility whereas bare glass is essentially immune to dry brushing. [ABSTRACT FROM AUTHOR]

Steel slag has been investigated as a potential aggregate for pavement-wearing courses in road engineering. The volume stability, resistance to high and low temperatures, and water stability for asphalt mixtures containing steel slag have been widely studied. As for the skid resistance, previous studies have primarily focused on the initial performance. The relationship between the steel slag's appearance morphology and skid resistance during the wearing process remains to be further explored. It is essential to undertake a comparative study on the long-term skid resistance of steel slag and conventional aggregates to address the differences. This research picked two steel slags and two types of conventional aggregates (granite and limestone) as research samples. The chosen aggregate samples underwent various degrees of wear treatment with the Los Angeles abrasion machine, and their angularity was examined utilizing an aggregate image measurement system (AIMS). Based on the polishing pre-treatment, the micro-texture of the aggregates was observed with the assistance of a laser confocal microscope, and its correlation with skid resistance was determined. British pendulum number (BPN) tests were also conducted and analyzed at various polishing durations. The results show that steel slag has a low abrasion rate and higher initial angularity and abrasion resistance compared to natural stones. The micro-texture analysis demonstrates that steel slags have a coarser roughness, more contact points, and more durable abrasion resistance. Additionally, the fluctuations in BPN further prove that steel slag has superior initial and sustained skid resistance. Overall, steel slag can be a promising alternative for pavement-wearing course aggregate due to its superior long-term skid resistance. [ABSTRACT FROM AUTHOR]

This is a reply to the recently published paper Road markings and microplastics- A critical literature review. In our opinion, that paper presented a deceptive picture, of why we found it necessary to write a short reply where we comment on two major flaws: the stated lack of road markings in environmental samples, and the definition of microplastics. We discuss possible reasons for the absence of positive findings in environmental samples and relate that to two of the major issues within the research area of microplastics- the complexity of environmental samples and the analytical difficulties. We also argue that it can be relevant for upcoming studies to report both total microplastic concentration and polymer content to facilitate the comparison between studies since the definition of microplastics might change over time. [ABSTRACT FROM AUTHOR]

Wood-plastic composites (WPC) can be regarded as environmentally-friendly materials which are mainly manufactured with recycled wood and thermoplastics. However, it is difficult to decorate WPCs with wood veneer using the types of polar adhesives which are commonly used in the woodworking industry due to the nonpolar and nonporous surfaces of WPCs. In the present study, four kinds of abrasive material, including sanding paper, industrial scouring pad, nylon and steel wire wheels were evaluated as a means of promoting adhesion between a wood fiber/high-density polyethylene (WF/HDPE) board and wood veneer using an isocyanate-crosslinking polyvinyl acetate adhesive. Based on the test results of bonding strength and water resistance, it was found that neither the sanding paper commonly used in the woodworking industry, nor steel wire commonly used in the WPC industry were particularly effective, with the scouring pad approach (nylon substrate entangled with silicon carbide) being the best choice. Scanning electron microscopy, Fourier-transform infrared spectroscopy, contact angle measurements, and roughness tests were used to analyze the surface properties of abraded surfaces. Although all four abrasion materials scraped the surface plastic layer off and exposed the wood fibers, they formed significantly different morphologies and affected surface wettability. A combination of suitable surface roughness and enough fiber exposure was found to be necessary for a WF/HDPE composite to build a good glue line. Abrasion with an industrial scouring pad might be a simple and effective method for removing a surface layer and aiding the application of a decorative layer. [ABSTRACT FROM AUTHOR]

Synergistic erosion caused by cavitation, abrasion and corrosion is a common issue for hydraulic and marine structures in rivers and oceans with high concentrations of sediments. Erosive experiments using a vibratory apparatus and a stirring apparatus, are performed on cement paste and mortar subjected to tap water, sediment suspensions (0.01–0.1-mm sizes and 30–150-kg/m3 concentrations), and sodium chloride solutions (0.5–15%). The experimental results demonstrate that cavitation erosion is the dominant failure mechanism. Micro jet and shock wave accompanied by the collapse of cavitation bubble clouds lead to a broadening of the original micro crack and pore. The cumulative mass losses linearly aggravate with the prolongation of exposure duration entering an acceleration period. The increasing sizes and concentrations of sediments aggravate the synergistic erosion due to the accelerated sediments by bubble collapse and heterogeneous nucleation of sediments. Sodium chloride weakens the cavitation resistance of cement mortar with a threshold value of 1.5% concentration. The mass loss caused by cavitation corrosion increases sharply at concentrations of NaCl smaller than 1.5% and then slowly increases. Chlorine ions penetrate the micro crack and result in the dissolution of the calcium silicate hydrate and the formation of the expanding compound with the enlarged porosity, decreasing the compressive strength. The addition of NaCl and sediment in the suspension aggravates the cavitation erosion and no suppression is observed. • Cavitation erosion comes to an acceleration period at 10 min and then enters a steady-state period. • Sediment and NaCl respectively aggravate cavitation erosion for cement paste and mortar. • A threshold value of NaCl concentration is 1.5% and before the value, cavitation corrosion sharply increases. [ABSTRACT FROM AUTHOR]

• Strong size dependency in wear rates in Bond abrasiveness test. • Wear rates deviate from linearity at short times and also at long tumbling times, when sample replacement does not occur. • Variation of product fineness as a function of paddle hardness. • Good correlation between % −1 mm in Bond abrasiveness test and LA abrasion index. Nearly 80 years ago Fred Bond proposed his abrasiveness test, also known as Allis Chalmers abrasion test, together with empirical equations that have been used to predict the wear of mill and crusher liners, besides grinding media. Although those equations have been widely criticized over the years, in particular owing to the limited accuracy of the correlations originally proposed to predict wear, it remains the most widely used test to measure ore abrasiveness in the minerals industry. The work analyzes the test, through experiments conducted under conditions that differ from those originally proposed by Bond in order to gain insights on metal wear and particle breakage. The effects of particle size, ore competence, metal hardness and time of batch operation are analyzed. It is shown that initial particle size strongly affects the rate of wear, that the intensity of fragmentation varies with hardness of the paddle and that the size distribution from the ground material offers a valid proxy for ore competence that may be useful in geometallurgical studies. [ABSTRACT FROM AUTHOR]

Particulate attrition is of interest for novel carbon-capture processes such as chemical looping combustion because the makeup cost of oxygen carrier is a significant portion of operating cost. Thus, models to study and predict attrition of various oxygen carriers in fluidized bed systems are being developed. One of the regions of concern in fluidized bed systems is the high-velocity jet region near gas distributors in a fluid bed. This work studies the attrition of hematite particles using a modified ASTM apparatus to measure the particle size distribution throughout the experiment. Bed weight and gas velocity were varied. Hematite particles above the corresponding threshold value had a severe variation of particle size distributions which decreased with time. Weight fractions of the sieves over time were fit to a linear, time-variant population balance model to offer insight into particle attrition. The first-order rate constant was modified as a decaying exponential. Unlabelled Image • Attrition of hematite particles studied using a modified ASTM apparatus. • Particle size distribution recorded throughout the experiment. • Data fit to a linear, time-variant population balance model for attrition insight. • First-order PBM rate constant was modified to a decaying exponential term. [ABSTRACT FROM AUTHOR]

The present study focuses on the comparison of cathodic arc deposited AlCrN (ternary coating) and Ag alloyed a-C (amorphous carbon base coating) on chrome nitride (CrN) medical grade 316 LVM stainless steel. The work comprises of morphological, structural, nanomechanical and tribological evaluation in physiological simulated body fluid (SBF) lubrication following conditions pertaining to simulated hip joint. According to the findings, H/E, H3/E2 and E coating /E substrate significantly effect the nanomechanical and tribological properties of the coatings. While a-C:Ag/CrN exhibited better L y value compared to AlCrN/CrN due to better surface quality, the later has shown higher L c2 value during nanoscratch test attributed to lower H3/E2 and higher plastic work done. Inspite of lower friction coefficient, a-C:Ag/CrN observed higher wear rate during simulated tribotest attributed to low hardness, separate graphitic structure due to Ag doping and sudden increase of friction coefficient ascribed to severe abrasive delamination of a-C:Ag top layer. The wear mechanism observed under SEM microscopy indicate severe adhesion of Ti6Al4V counterbody on AlCrN/CrN coated surface. The size of wear debris obtained with AlCrN/CrN-Ti6Al4V tribopair was larger in size compared to a-C:Ag/CrN-Ti6Al4V tribopair. Nevertheless, despite inferior surface quality and lower L y value and larger wear debris size, AlCrN/CrN coating performed better in nanoscratch (at L c2 value) and demonstrated lower wear in simulated tribotest in physiological SBF condition. [ABSTRACT FROM AUTHOR]

Hybrid designs with the combination of metal and long fiber reinforced thermoplastics (LFT) offer a great opportunity to reduce component weight for automotive applications. Production costs are typically high due to complex processes and challenging end machining. A complete manufacturing process chain for simultaneous hybrid design production is presented. Hybrid forming, a manufacturing process combining metal sheet forming, LFT compression molding and bonding, was developed to manufacture an automotive lightweight component, finally end machined by innovative waterjet techniques. Besides optimizing waterjet end machining strategies, waterjet controlled-depth machining was used to remove LFT material selectively, resulting in increased hybrid production flexibility. [ABSTRACT FROM AUTHOR]

Abrasive waterjet (AWJ) machining has proven to be one of the most flexible non-conventional production techniques for difficult-to-machine materials. However, the prediction of process results is challenging since multiple physical processes occur simultaneously. Until now, the use of alternative abrasive material for special applications has received limited attention. In this work, different solid materials of altered shape and mechanical properties were used to analyze the physical phenomena experimentally. A ceramic and a steel abrasive material of either circular or angular geometry were used. The experiments were conducted by AWJ controlled-depth machining on 42CrMo4 steel in various structural modifications regarding the interference of particle interactions. Furthermore the study aims to gain a fundamental understanding of the AWJ erosion process of different abrasive grit for a better prediction and optimization of AWJ machining, in particular for future applications. [ABSTRACT FROM AUTHOR]

A novel approach is presented for simulating non-spherical particles in the discrete element method (DEM). A particle's shape is described through a hierarchy of representations using spherical harmonic expansions. The expansion is computed at nodes, obtained by discretising the particle's surface. A low-degree expansion, i.e., one containing few terms, is sufficient to approximate a particle's overall shape without any surface texture. Expansions are computed to high degrees only at interparticle contacts, rather than for the entire particle, which reduces the computational cost. The advantages of this approach include the ability to simulate a wide range of particle shapes and adaptive resolution depending on spatial and temporal considerations. An additional unique benefit is that changes of particle shape due to chipping can be captured in DEM for the first time. This is accomplished by progressively omitting more of the highest-degree terms from the expansion to give an increasingly smooth surface. Unlabelled Image • Spherical harmonic expansions inherently contain a hierarchical description of non-spherical particles. • A set of coefficients ensures that low-degree shape expansions bound higher-degree expansions. • Identification of a suitable discretisation method to describe the particle's surface. • Possibility to simulate particles with adaptive fidelity, depending on location and time. • Abrasion processes captured by omitting terms from the spherical harmonic expansions. [ABSTRACT FROM AUTHOR]

Pad asperities in chemical-mechanical polishing (CMP) provide necessary forces for mechanical abrasion. This article investigates the abrasive behaviour of polishing pads at the asperity contact scale. A contact mechanics model predicts that compliant and soft asperities or rigid and hard asperities may solely achieve either large contact area or high indentation depth respectively, whereas bi-layered asperities can enable both the enlarged contact and deep abrasion. Hemispherical pad micro-asperities with precise dimensions, including the new bi-layered design, were fabricated using thermal reflow and micro-replica molding techniques and their polishing behaviours were experimentally compared using a pin-on-disk polishing setup. [ABSTRACT FROM AUTHOR]

Attrition rate R a,j versus new stirring factor α new. • The new stirring factor α new was a key factor for jet attrition. • The α new fit well the effect of bed height on jet attrition. • The top size of fines formed by attrition increased with α new. • The attrition rate increased linearly with α new. Particle attrition is a major challenge when handling bulk solid materials with fluidized beds due to its ability to cause particle loss. Herein, the particle attrition induced by the gas jets on a perforated plate distributor in a bubbling fluidized bed was investigated for CO 2 adsorbent particles. An attrition tube, which used air as the fluidizing gas, was used as the fluidized bed. At a constant fluidizing velocity, the initial static bed height and orifice gas velocity were considered as variables. It was confirmed that abrasion dominated the particle attrition. The trend indicating the change in the maximum size of the particles (d pm,a) formed by attrition followed that of the attrition rate (i.e., the formation rate of fine particles via attrition). A new stirring factor that combined the model developed by Werther and Xi with the original stirring factor adequately explained the effect of the static bed height on both the attrition rate and d pm,a when the initial static bed height was greater than the length of the orifice gas jet that penetrated the bed. The attrition rate increased linearly with the new stirring factor. However, d pm,a increased exponentially with the new stirring factor. Relationships were successfully proposed to enable the estimation of the attrition rate and d pm,a for the CO 2 adsorbent particles. This study provided the evidence indicating the significance of the effect of bed height on particle attrition induced by the gas jet on the distributor. Moreover, proper models for correlating the attrition rate and the maximum size of the fine particles formed by attrition in the bubbling fluidized bed were provided. [ABSTRACT FROM AUTHOR]

Transport codes used for space radiation protection require accurate nuclear fragmentation cross sections as input. The fragmentation process is modeled in two stages: a fast step, called abrasion or knockout, and a slower step, called evaporation or ablation. In this work, the ablation step is calculated via Monte Carlo (MC) methods using the recently modified legacy EVAporation (EVA) code. The code is based on the Weisskopf-Ewing particle emission formalism and has been extensively overhauled and modernized. Updates include a new nuclear mass table and modifications to the nuclear level density expression. The new formulation enables calculated results to exhibit the odd-even effect observed in experimental measurements. The revised ablation code, EVAporation-University of Tennessee, Knoxville (EVA-UTK), has been coupled with the quantum multiple scattering abrasion formalism incorporated in the nuclear fragmentation code, Optical PoTential FRAGmentation (OPTFRAG), and resulted in substantial improvements in agreement between fragmentation cross section estimates and experimental measurements. [ABSTRACT FROM AUTHOR]

Silver (Ag) doping in carbon matrix have shown promising results in anti-bacterial potency. Adhesion of diamond-like-coating (DLC) on steel substrates is inferior; however, this can be circumvented by employing interlayers to it. In the present study, Ag incorporated DLC coating with chromium interlayer (Ag-DLC/Cr) was deposited on surgical SS using cathodic arc deposition technique. The topographical, morphological and structural analysis of the coating was performed using AFM, XRD, Raman spectroscopy and FTIR studies. The nanomechanical and wear performance of the coating was evaluated using nanoindentation, nanoscratch, dry sliding simulated tribotest and Vickers microhardness tests. Depositing chromium interlayer to DLC film resulted in improved hardness, adhesion and elastic modulus of the substrate due to sp3 content and formation of transmittal chromium carbide in the coating. Moreover, Ag doping causes formation of ductile bridges in carbon matrix enabling it to absorb more energy during deformation. While the coating exhibited higher strain hardening exponent and lower plastic work contributing to higher scratch hardness, lower deformation and no pile-up; the coating simultaneously resulted in reduction of wear rate by four orders of magnitude. SEM micrographs suggest emanation of lubricious film during tribotests due to dispersion of soft Ag clusters on the top layer, resulting in lower friction coefficient. Also, the sticky nature of DLC particles on the counter-face acted as an anti-adhesive agent thereby preventing transfer of material from the counterbody during tribotest. Lastly, the friction dynamics during dry sliding and Vickers microhardness test post tribotests highlights enhanced durability of Ag-DLC/Cr coated substrates. [ABSTRACT FROM AUTHOR]

TiAlN and AlCrN coating has been deposited on MDC-K hot work tool steel by PVD technique. The microstructure, elemental composition, nanomechanical and wear properties of bare nitrided and coated surface were evaluated using XRD, Raman spectroscopy, FE-SEM along with EDS, nanoindentation and nanoscratch test. AFM have showed improvement in surface with reduction in friction coefficient by ∼47.62% and ∼45.71% with TiAlN and AlCrN coating respectively. The mechanical properties of MDC-K tool steel substrate such as hardness, elastic modulus and strain hardening exponent got improved post coating wherein TiAlN coating had exhibited higher wear resistance (H/E), improved plastics deformation resistance (H3/E2), high scratch hardness and lower specific wear rate compared to AlCrN coating. This led to lower pile up and plastic deformation in TiAlN coating. In addition to this, wear behavior of bare nitrided, TiAlN and AlCrN coated surface were evaluated under different tribological conditions. Bare nitrided surface worn out due to abrasive wear mechanism whereas AlCrN coating exhibited both smooth and rough surface due to adhesive and abrasive wear mechanism. Furthermore, TiAlN coated surface exhibited lower specific wear rate and superior micro-hardness compare to bare nitrided and AlCrN coated surface post tribotests. [ABSTRACT FROM AUTHOR]

For an effective machining of high-performance materials, high-strength cutting materials, e.g. cubic boron nitride (CBN), with high resistance to any kind of wear are used. However, these materials must also be able to be machined in order to produce geometric elements such as chip breakers or chip grooves. According to the current state of the art, grinding and laser beam technology are used for this purpose. In this paper, an attempt was made to use the erosive removal mechanism of abrasive water jet technology to cut a harder material with a softer abrasive. Within the framework of a full factorial test plan, the removal rate, the macroscopic kerf geometry on CBN were investigated by means of abrasive water jet machining. It could be proven that it is possible to remove a harder material with a softer abrasive by means of abrasive water jet technology. [ABSTRACT FROM AUTHOR]

The effect of Y 2 O 3 addition on structure, mechanical properties and tribological properties of Al 2 O 3 -13 wt% TiO 2 coating was investigated. The addition of 20 wt% Y 2 O 3 resulted in better densification, stabilization of alpha (α) alumina phase and improvement in fracture toughness of Al 2 O 3 -13 wt% TiO 2 coating. Abrasive wear tests were performed over a range of loads and sliding speeds. The stabilization of α alumina phase further increased with an increase in severity of wear test conditions, as noted from X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS) analysis of worn coatings. Al 2 O 3 -13 wt% TiO 2 -20 wt% Y 2 O 3 coating displayed lower friction coefficient and lower abrasive wear rate than Al 2 O 3 -13 wt% TiO 2 coating, which was due to synergistic effect of α alumina phase and formation of magneli phase oxide of titanium; Ti 2 O 3. Friction energy map was used to rationalize observed wear rates, to identify different regimes of wear and degradation modes of coatings. [ABSTRACT FROM AUTHOR]

A new method to model the abrasion of granular particles using the discrete element method is demonstrated in this paper. This new, simple method is based on a classical theory of abrasive wear, relating the volume of solid lost to the frictional work at particle contacts. The modelling technique is demonstrated in simulations of railway ballast using realistically-shaped particles, which are compared to experimental data. The new abrasion model correctly introduces stress-dependent behaviour at small strains into the simulations, which is essential for any realistic discrete element model. [ABSTRACT FROM AUTHOR]

This paper investigates the limitations of widely used 3D Wadell's roundness and true sphericity metrics for characterizing granular materials. It introduces two improved indices: the mesoscale interlocking index and the radial distance factor. The study involves diverse particles scanned using optical interferometry and X-ray computed tomography. A mean curvature method is employed for surface segmentation, and a computationally efficient 3D mesh simplification procedure is proposed. Python scripts are developed for surface segmentation, mesh simplification, and 3D shape characterization. The new indices are validated by assessing angular and rounded 3D particles and changes in the shape of aggregates through the Los Angeles abrasion test. The results demonstrate the ability of the proposed indices to differentiate visually similar particles with identical Wadell's roundness and true sphericity, showcasing their effectiveness in accurately describing particle shape. The statistical distribution of 3D particle curvatures offers an alternative method for understanding particles' shape and abrasion. [Display omitted] • Accurate local curvature-based methods for segmentation and shape characterization. • Enhanced Shape indices: Mesoscale Interlocking Index and Radial Distance Factor. • Local curvatures for 3D shape and abrasion: an alternative method. • Abraded aggregate particles show enhanced index sensitivity to minor shape change. [ABSTRACT FROM AUTHOR]

In the Xinjiang region of China, transmission tower coatings undergo consistent wear from wind gravel flow (WGF), which jeopardizes their durability. This study assesses the effect of wind speed, attack angle, and gravel size on the durability and wear patterns of graphite/epoxy coatings by experiment and simulation. The results show that these coatings exhibit characteristics that bridge the gap between elasticity and plasticity, and larger gravel particles cause more damage than their smaller counterparts. From our experiments, a graphite/epoxy coatings abrasion model was formulated. Additionally, numerical simulations provided insights into the pressure variations on the abrasion surface and the dynamics of the neighboring flow field. This study provides guidance for the protection of electrical systems in the Gobi's windy areas. [ABSTRACT FROM AUTHOR]

• Surface modification of MFPW flakes improves the delamination process. • Surface modification allows the penetration of the dissolving agent inside MFPW. • The delamination time strongly depends on the distance between the microholes. • Abrasion of the MFPW surface increases the specific surface of the cross section area. Multilayer flexible packaging waste (MFPW) represents a critical issue in the field of waste management. The heterogeneous composition of this type of plastic makes its recyclability challenging. In this context, the delamination process appears to be a promising way to recycle the polymers layers separately. However, this process is still limited for a few MFPW. This work propose an innovative way to improve the delamination process using three surface modification techniques (mechanical and laser microperforation (µP), and abrasion) on the MFPW surface in order to accelerate the diffusion of the dissolving agent. The delamination was tested in a 10 % sodium hydroxide solution at 25ºC. Under this study, the mechanical µP and the abrasion gave the best results of delamination compared to the laser µP (total delamination in 25 min vs 45 min, respectively). It was concluded that the distance between the microholes was an important factor in both µP techniques. [Display omitted] [ABSTRACT FROM AUTHOR]

Presently, scrap tire polymeric fibers (STF) have limited reuse value in most countries of the world, hence it is largely land filled or used as an eco-unfriendly tire derived fuel (TDF). Unfortunately, toxic gases and acids could be released from these aforementioned STF management strategies. Therefore, in this study, an alternative reuse approach for the STF was explored; the possibility that it could enhance the flexural post-crack residual strength and wear resistance of cement composites were examined. Furthermore, the likelihood of improving the aforementioned properties through the hybridization of the STF with commercial macro fibers such as steel hook-end (HE) and polypropylene (PP) fibers was also evaluated. The cement composites investigated consist of a set of 0.50 water-to-cement (w/c) ratio mortar and two sets of concrete batches corresponding to 0.50 and 0.40 w/c ratios. Results indicate that the post-crack residual strengths of mortar and concrete mixtures singly reinforced with the STF was about 0.10 MPa and 0.10 – 0.20 MPa, respectively. Hence, these STF reinforced cement composites have no useful structural application value. However, with the hybridization of 0.35% STF with 0.2 – 0.5% macro fibers, mortar mixtures with post-crack residual strengths ranging from 1.4 to 3.1 MPa were attained as a result of the positive synergy between the STF and the HE fibers. Hybrid 0.35% STF and 0.35% HE fiber reinforcement of concrete also led to a positive synergy and improvement in post-crack residual strength capacity, especially for the 0.50 w/c ratio mixture. Relative to the plain concrete, 0.35% STF or hybrid combination of 0.35% STF and 0.35% PP had no impact on concrete abrasion resistance. Conversely, cumulative volume loss of concrete reinforced with hybrid 0.35% STF and 0.35% HE fibers decreased by approximately 8.9% and 16.1% for 0.50 and 0.40 w/c ratio concrete mixtures, respectively. All-in-all, these results suggest that in lieu of its present use as a TDF, the STF hybridized with HE fibers could actually be used as a sustainable, discrete fiber reinforcement for cement-based repair applications where slightly enhanced flexural post-crack performance and resistance to abrasive wear are desired. • Alternate reuse option for scrap tire fibers (STF) in cement composites was studied. • Composites singly reinforced with the STF had limited post-crack residual strength. • Post-crack performance improved with the hybridization of the STF with steel fibers. • But, improvement in residual strength was only obtained in low-strength composites. • Wear resistance was also enhanced due to synergy between the STF and steel fibers. [ABSTRACT FROM AUTHOR]

Topography studies of concrete-ice abrasion were made to proceed in our understanding of the mechanisms of concrete wear by ice on Arctic offshore structures. The effects on various initial surfaces of a B75 normal-weight concrete (smooth, rough, sawn) and on the sawn surface of a LB60 lightweight concrete were studied during concrete-ice abrasion experiments. The degradation of a concrete surface appears mainly as valley formation resulting from air voids opening, or aggregate protrusion and cutting of peaks. The various initial roughness conditions were found to lead to an evolution with both increasing (at both meso- and microscale) and converging roughness. Protrusions from both lightweight and normal-weight aggregates were observed on sawn surfaces. Greater abrasion is seen on lightweight concrete and its initial roughness was much affected by the porous aggregate. • Concrete surfaces with different initial roughness were abraded by ice. • The concrete roughness increased at different scales during the test. • Abrasion of concrete was related to opening of voids and cutting of peaks. • Protrusion of both light and normal density aggregate was observed. • The wear caused sharp wear particles from both concrete and ice. [ABSTRACT FROM AUTHOR]

Two new low alloyed steels were developed with different fracture toughness values but at similar level of hardness with same composition and microstructural phase. The steels were subjected to impact-abrasion wear test. This work examines specifically the additional role of toughness during impact-abrasion wear, using a newly developed high toughness steel. Microstructural characterisation of the damaged samples revealed that better toughness helps resist both impact and abrasion damage. • The main aim of the work presented here was to examine specifically the role of fracture toughness of a newly developed steel on impact abrasion. • This study is the first of its kind to develop steels with two levels of toughness without changing either composition or micro structural phase, and at similar hardness level. • The newly developed steel which has high toughness performed better in impact abrasion wear compared to the high hardness and low toughness steel. Both steels have same composition, and same microstructural phase. • The steel with the greater ductility revealed a greater hardness in the vicinity of the wear surfaces after the impact-tumbler tests despite its initial lower hardness. [ABSTRACT FROM AUTHOR]

Abstract A transparent spinel ceramic is compared to different types of glasses, including unhardened and hardened material, as well as a polymer in terms of mechanical behavior and optical appearance before and after mechanical exposure. The mechanical behavior of the materials is compared on the basis of depth-sensitive indentation and ring-on-ring bending tests, deriving hardness, elastic modulus, and fracture stress data. The focus of this research is the analysis of specimens after certain exposure times of sand blasting and different loads during scratch tests via weight balance, confocal laser scanning, and optical microscopes to assess wear resistance including surface roughness, mass loss, critical loads, and initial damage. Results are critically discussed in terms of differences in the performance of the diverse materials and the correlation of optical appearance, abrasive behavior, and apparent scratch testing damage. The overall comparison of properties and application relevant to damage resistance indicates that the tested transparent ceramic and the surface hardened Gorilla glass are superior to all other tested variants. [ABSTRACT FROM AUTHOR]

Highlights • RAP fraction up to 35% may be used for DBM mixes without rejuvenator. • WMA additive ensure the longevity even in the worst conditions of moisture. • WMA mixes have better long-term performance than HMA mixes. • WMA as an anti-ageing product for asphalt mixes. • Cantabro abrasion for dense asphalt mixes indicate bonding. Abstract This paper is an attempt to enhance the long-term performance of Reclaimed Asphalt Pavement (RAP) inclusive dense bituminous macadam (DBM) mixes, in post ageing condition, via inclusions of a Warm Mix Additive. Two sources of Reclaimed Asphalt Pavement (RAP) with two inclusion proportions (35% and 70%) were considered. The effect of inclusions of both the technologies (RAP & WMA) on various properties of DBM mixes such as Marshall Stability, retained Marshall Stability, indirect tensile strength (wet & dry), rutting resistance and Cantabro abrasion loss were studied. Inclusions of WMA was found to significantly improve the aforementioned properties of the DBM mixes regardless of the type of aggregate used. Moreover, the RAP-WMA mixes were found to retain much of its properties even after long-term ageing as compared to RAP-HMA mixes. RAP fraction up to 35% may be used for DBM mixes without much compromising the mechanical and durability properties of the same (as found in the present study). Incorporation of WMA in these mixes would further improve the properties and would ensure the longevity even in the worst conditions of moisture. [ABSTRACT FROM AUTHOR]