High Roughness Research Articles

A nanofiltration membrane with outstanding antifouling ability: Exploring the structure-property-performance relationship

Membrane fouling is inevitable during nanofiltration of industrial liquids. Understanding the influence of membrane physicochemical properties and structures on its antifouling performance can guide the membrane selection and preparation. In this study, the antifouling ability of three commercial nanofiltration membranes (NF270, NFA4 and DK) was assessed using organic foulants with different charge patterns. Besides, the pristine and fouled membranes were systematically characterized. The results showed that although the negatively charged polyamide membrane had a strong antifouling ability to negatively charged substances, the fouling extent was still affected by the membrane pore size distribution. For the small foulants with positive charge, driven by electrostatic adsorption effect, they were easier to be anchored on the membrane surface with higher roughness. Due to the synergistic effect of membrane charge and roughness, the flux decay ratio increased from 5.1% for the NFA4 to 63.1% for the DK with more negative charge and highest roughness. Moreover, according to FTIR, XPS deep profiling and SEM cross-section analysis, it was found that the structure of the separation layer (e.g., single/double layer or cross-linking density in horizontal/longitudinal) closely related to its antifouling performance. Therefore, a nanofiltration membrane with narrow pore size distribution, moderate charge, smooth and hydrophilic surface is more prone to resist organic fouling formation. The outcomes of the work also offer several strategies to prepare antifouling nanofiltration membranes.

Extraction and Characterization of Antimicrobial surgical Suture from the bast of Tinospora Cordifolia

ABSTRACT Tinospora cordifolia, a climbing plant of south-east Asia, has been used as an Ayurveda for thousands years for its extraordinary medicinal properties. Two of its special properties are antimicrobial and anti-infection property. The objective of the study is to produce surgical suture from the bast of Tinospora cordifolia and evaluate the related chemical, physical and mechanical properties of that suture. In this work, the antimicrobial activity analysis by agar disc diffusion method, tensile strength analysis with digital single thread strength tester for both straight pull and knot pull, creep test, thread count by Beesley’s Balance, moisture analysis by Reynold & Branson rapid regain tester and surface roughness analysis by Homel roughness tester have been conducted. The Agar disc diffusion method indicates the thread contains antimicrobial properties, tensile strength is perfect for being used as a surgical suture with 38% reducing in knot pull than straight pull, fineness is also in the range where moisture content and regain is more than most of the natural fibers with higher roughness, lacking, suggesting a perfect natural surgical suture for Tex-medical applications.

Magnetic Nanoparticle-Based Surface-Assisted Laser Desorption/Ionization Mass Spectrometry for Cosmetics Detection in Contaminated Fingermarks: Magnetic Recovery and Surface Roughness.

In this work, we propose a matrix-free approach for the analysis of fingermarks (FMs) contaminated with five cosmetic products containing different active pharmaceutical ingredients (APIs) using surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). For this purpose, a magnetic SALDI substrate based on Fe3O4-CeO2 magnetic nanoparticles was prepared, characterized, and optimized for the analysis of contaminated FMs without sample pretreatment. Initially, groomed FM and cosmetic products were separately analyzed, and their major components were successfully detected. Subsequently, FMs contaminated with Ordinary serum and Skinoren, Dermovate, Bepanthen, and Eucerin creams were analyzed, and components of FM and cosmetics were detected. The stability of the cosmetics in FMs was studied over an interval of 28 days, and all components showed good stability in FM for 4 weeks. Recovery of contaminated FMs from different surfaces utilizing a few microliters of the magnetic substrate was carried out using a simple external magnetic field from ceramic, plastic, metal, and glass. Successful retrieval of the API and FM components was achieved with magnetic recovery, and glass exhibited the best recovery, whereas ceramic tile demonstrated the lowest recovery. This was supported by atomic force microscopy study, which revealed that the ceramic surface had higher roughness than the other surfaces employed in this study, which adversely affected the magnetic maneuvering. This proof-of-concept investigation extends the application of SALDI-MS in forensic analysis of contaminated FMs by exploring cosmetics as exogenous materials and their stability and recovery from different surfaces.

Facile formation of porous, multilayer reduced graphene oxide electrodes using electrophoretic deposition and flash sintering

A reduced graphene oxide (rGO) film is mechanically fragile; therefore, transferring it to another substrate without damage is crucial. Hence, a technique that facilitates the formation of an integrated rGO film that holds adhesion with the substrate is desired. Moreover, a rGO film on metal is promising as an electrode for energy storage devices. This work presents the formation of rGO film on copper using electrophoretic deposition (EPD) and flash sintering. Briefly, a stable aqueous dispersion of graphene oxide (GO) layers was used to form a uniform GO film on copper at a fixed deposition voltage and time duration. To reduce the GO film without detaching it from copper, pulse energy (1–10 J cm−2) was varied for a fixed exposure time (10 ms) and a single micropulse. At pulse energy of 6 J cm−2, the structural studies indicated turbostratic stacking (decreased interlayer spacing) and restored crystallinity (decreased peak intensity ratio of D and G bands). The morphology showed voids between stacked rGO layers and high roughness in the film. The reduction resulted in mesoporous and high surface area (373 m2 g−1) multilayer rGO film. Due to restored electrical conductivity, the rGO film showed a specific capacitance of 475.8 F g−1 at a scan rate of 2 mV s−1. An increase in contact angle from ∼66° to ∼81° also validated the reduction. The combination of EPD and flash sintering offers rapid and eco-friendly formation of binder-free rGO film on copper, promising as an electrode for supercapacitors.

Interface analysis of Mg/Sc and Sc/Mg bilayers using X-ray reflectivity

• Interfaces at the Mg/Sc and Sc/Mg bilayers are investigated. • Bilayers are studied by secondary ion mass spectrometry and x-ray reflectivity. • Mg-on-Sc and Sc-on-Mg interfaces in the bilayers are found to be asymmetric. Mg/Sc and Sc/Mg bilayers were studied to investigate their interfaces. Time-of-flight secondary ion mass spectroscopy and grazing incidence x-ray reflectivity are combined to determine the realistic structure of the bilayer stack: thickness, refractive index, and roughness of layers and interlayers respectively. In addition, soft x-ray reflectivity measurements provide sensitive information about the chemical environment of scandium, when the incident photon energy is tuned in the vicinity of the Sc L-absorption edge (∼ 400 eV). Both Mg-on-Sc and Sc-on-Mg interfaces have high roughness (∼1 nm) and a MgSc compound interlayer but are shown to be asymmetric.

Extraction and mapping of downpour impact and their Cumulonimbus origin, 20 May 2020, Vâlcea (Romania) via Sentinnel-1 SAR dual polarization

The aim of this work is to study the impact and characteristics of the meteorological phenomenon that occurred on May 20, 2020 in Vâlcea County, Romania. For this purpose, we used SAR radar images from the Sentinel-1 series at different dates, before, during and after the event. The methodology consists in exploiting and combining the two polarisations, VV and VH, of the recorded radar wave. The results obtained can be summarised as the extraction of areas completely covered by water and areas characterised by high roughness and very high humidity. The latter (roughness/humidity) can have two different origins. The first one corresponds to an area affected by downpours, giving a high roughness due to the interaction of water drops with the ground and also to the presence of hail, amplified by the wind factor. On the other hand, the second one coincides, quite simply, with the presence of a thundercloud, precisely a Cumulonimbus, which formed in that particular place as a result of the favourable geomorphological characteristics and meteorological conditions, giving a high humidity due to the high water content. We also determined the total impacted area of about 96.71 km2, whose 60.17 km2 of water covered area, which is 2.45% of the study area. The remaining 36.54 km2 (1.49%) represents the affected rough surface, located in the plain, or the humid surface corresponding to the area of the Cumulonimbus head covering the plain.

Curvature modulated structural and magnetic properties of CoO/Co thin films deposited onto 2-D nanosphere array

The importance and applications of nanoscale magnetic storage devices has been of current interest owing to the extensive research interest in magnetic nanocaps. Continuing their research trend, we have attempted to synthesize and characterize an important isolated magnetic nanocaps system constituting Co and its oxide. CoO/Co thin films were deposited onto self-assembled arrays of polystyrene (PS) nanospheres (∼600 nm diameter) under ultra-high vacuum environment using electron beam evaporation technique. The magnetic and structural properties of these nanostructures were then compared with those of simultaneously deposited films on bare Si substrate (referred to as reference film). The studied film and the reference film were grown in polycrystalline manner as observed from X-ray diffraction measurements while their roughnesses as observed from X- ray reflectivity were quite different. X- ray reflectivity showed that for the reference films well defined Kiessig oscillations appeared suggesting low roughness in the deposited films, while the films on PS followed the curvature of underlying nanospheres and thus have very high roughness resulting in the disappearance of Kiessig oscillations. Magnetic measurements exhibited a drastically high coercivity when the substrate was changed from flat (Si) to curved one (PS). As the film thickness was increased, the coercivity first showed a slight decrement (4.92 kA/m) and beyond 40 nm film thickness, it showed some enhancement (14.2 kA/m). The exchange bias measurements also showed interesting results with variation in film thickness. Co 10 nm film deposited on PS showed negative exchange bias of −127 kA/m which decreased to −26 kA/m in 100 nm film. The overall results were explained by correlating the magnetic and microstructural properties of the thin films as a function of thickness.

Loss of reef roughness increases residence time on an idealized coral reef

Through idealized, numerical models this paper investigates flows on a reef geometry which has received significant attention in the literature; a shallow, fringing reef with deeper, shore-ward pools or lagoons. Given identical model geometries and varying only reef flat drag coefficients between model runs (C_D = [0.001,0.005,0.01,0.05,0.1]), two distinct circulation patterns emerge. One is related to low reef water levels and high roughness, and efficiently flushes the entire reef system resulting in low residence times (an ‘open reef’). The other is related to high reef water levels and low roughness, and in spite of the development of an offshore undertow, this dynamic is inefficient at flushing the reef-pool system and facilitating exchange flow with offshore waters (a ‘closed reef’). This paper shows that even given indistinguishable geometry and offshore conditions, this information is insufficient to predict reef dynamics, and suggests that reef roughness (and thus reef health) plays a comparable role in determining circulation patterns and residence times. Furthermore, a transition from open to closed or vice versa caused by e.g., a loss of reef roughness or increase in mean sea level could have implications for transport and mixing of nutrients and water masses, as well as larval dispersal.

Correlation between Thickness and Optical Properties in Nanocrystalline γ-Monoclinic WO3 Thin Films

Results from the analysis of the variation of structural defects, such as oxygen vacancies indicate that by adjusting the thickness of the WO3 films, fabricated by DC reactive sputtering, it is possible to modulate the oxygen vacancies concentration. This has a tremendous influence on the applications of these semiconductor materials. The thicknesses analyzed here are 42, 66, and 131 nm. After the annealing process at 500 °C, films were directly transformed to a stable γ-monoclinic crystal structure with P21/n space group, with a preferential orientation in the (200) plane. Atomic force microscopy exhibits nanometer range particle size with the highest roughness and higher surface area for the thinner film. FTIR analysis shows the presence of characteristic bands of the double bond stretching vibrational modes (W=O) and stretching vibrations of the γ(W-O-W) bonds corresponding to the monoclinic WO3. Raman bands located at 345, and 435 cm−1 are ascribed to the presence of W5+ species that induces the formation of oxygen vacancies VO. The thinner film shows a decrease in the optical indirect band gap attributed to the formation of oxygen vacancies in combination with W5+ species that induce the formation of energy states within the forbidden band gap range.

Digital printing systems and office papers interactions and the effects on print quality

Abstract In this study, electrophotographic printing and inkjet printing systems were applied to some commercial A4 office papers and their effects on print quality were determined. It is to evaluate the print quality by determining the test parameters that measure the print quality by applying electrophotographic printing and inkjet printing systems to some commercial office papers that have determined the surface properties and optical properties supplied from the market. Print quality was measured by testing with parameters such as delta gloss 60°, print lightness, print chroma, print density. As a result of the tests determined for print quality; print density values were low in A4 office papers with high roughness and porosity values, and the specular gloss values of the samples decreased in both printing applications. In electrophotographic printing; it was determined that darker colors formed with print lightness parameter, and the color scale increases in two-sided printing with print chroma values. It was determined that the color scale of print chroma values increased in two-sided prints. It was determined that mostly some commercial office papers were positively affected by printing on one side in inkjet printing and by printing on two-sided in electrophotographic printing.

Evaluation of root surface roughness produced by hand instruments and ultrasonic scalers: An in vivo study.

Background. The aim of periodontal treatment is to remove bacterial plaque and dental calculus by hand and power-driven instruments. However, the comparison of the effectiveness of these instruments has always been controversial. Therefore, this in vivo study investigated and compared the effects of hand and ultrasonic piezoelectric instruments on the roughness of dental surfaces under an atomic force microscope (AFM). Methods. In this study, 35 periodontally hopeless teeth were selected and randomly divided into four groups (n=7). The control group consisted of teeth that had to be extracted for orthodontic or prosthetic treatment (n=7). In group one, scaling and root planing were performed using hand instruments. In other groups, scaling and root planing were performed using piezoelectric ultrasonic instruments with low to high power, respectively. Then the scaled teeth were extracted for analysis under an atomic force microscope. Results. This study showed that root roughness significantly differed between different experimental groups (P<0.027). The root roughness (Rq) in the SRP2 group significantly differed from the control group (P<0.05), while no significant differences were observed between the other groups. Furthermore, the least roughness was observed in the SRP3 group, with the highest roughness in the SRP2 group. Conclusion. Within the limitation of this study, there were no significant differences in surface roughness between different powers of the ultrasonic device.

Development and Investigation of Mesoporous Bioactive Glass/Zein Coatings Electrodeposited on Titanium Alloy for Biomedical Applications

The objective of the present work was the development of cathodic electrophoretic deposition (EPD) to obtain composite coatings of mesoporous sol–gel glass (MSGG) particles embedded in a zein matrix on Ti-13Nb-13Zr substrates. To deposit robust and repeatable coatings, a direct current EPD and pulsed direct current EPD as well as the deposition kinetics were investigated, including the deposition yield and deposition rate. The stability of the suspension was determined based on the zeta potential and conductivity. Macroscopically homogeneous coatings with a thickness of about 10 µm and various volume fractions of MSGG were subjected to further examination. Coatings were uniform, exhibiting open porosity and showing excellent adhesion to the substrates. Both zein and MSGG particles revealed an amorphous structure. The coated substrates demonstrated greater resistance to electrochemical corrosion in Ringer's electrolyte in comparison with the virgin (non-coated) substrate. The coatings showed high roughness and moderate hydrophilicity. The incubation of the coated substrates in concentrated 1.5 simulated body fluid (1.5SBF) showed the formation of carbonate hydroxyapatite. The composite coatings showed improved antibacterial properties against gram-negative E. coli and gram-positive S. aureus bacteria compared to pure zein coatings. Electrophoretic MSGG/zein composite coatings should be further investigated in terms of their osteoconductive behavior, to confirm their suitability for medical applications in orthopedics.

Effect of roughness and acidic medium on wear behavior of dental resin composite

BackgroundThe aim of the study was to investigate whether the citric acid and rough surface have a synergistic effect leading to severe wear behavior of resin composite.Materials and methodsDisk-shaped (Ø15 × 1.5 mm) specimens of resin composite (n = 12) with different initial roughness were prepared. Reciprocating ball-on-flat wear tests were performed under distilled water and citric acid (pH = 5.5) respectively. The coefficient of friction (COF), wear volume loss, and duration of the running-in period were quantified to assess the wear performance. And the values were analyzed with one-way ANOVA (α = 0.05). Regression analysis was applied to examine the influence of Ra values and mediums on the wear data. The wear morphology was analyzed by scanning electron microscopy and a 3D profilometer.ResultsThe average COF was higher in distilled water than in citric acid but was independent of the surface roughness. For the composite, the volume loss of worn area and running-in period increased with surface roughness when tested under distilled water. However, these increasing trends were not found in citric acid. All specimens exhibited mild wear behavior with low COF and less superficial abrasion in acidic medium.ConclusionsThe effect of initial roughness on wear behavior depends on the medium. In distilled water, resin composites with high initial roughness exhibit a longer running-in time, which eventually leads to a significant increase in material loss. The adverse effects of high roughness can be alleviated by the lubrication of citric acid, which can maintain a mild wear behavior regardless of initial surface roughness.

Effect of chemical post-processing on surfaces and sub-surface defects in electron beam melted Ti-6Al-4V

Surfaces after chemical post-processing treatments of electron beam melting (EBM) produced Ti-6Al-4V have been studied. Targeted chemical treatment allowed the study of variation in surface quality with material removal depth. Characterization of surface and defect morphologies were made, comparing two chemical post-processing methods, Hirtisation® and chemical milling with different milling depths. Surface topography was characterized using white light interferometry and subsurface defect distribution was studied using X-ray computed tomography (XCT). The morphology of the surface at different milling depths was compared to the sub-surface information from XCT scans of the as-built material. Furthermore, Hot Isostatic Pressing (HIP) treated material was documented for comparison. Results show that post-processed surfaces contain a number of different defects of mixed morphology, position and origin. Post-processing deteriorates the surface quality with increased removal depth due to the presence of sub-surface defects. The position of sub-surface defects in relation to the material surface coincides with the depth at which contour-hatch interactions are likely to have occurred during the EBM building process. The distribution of this sub-surface defect population is anisotropic in the building (horizontal) plane and reasons for this are explored. Hirtisation® produces surfaces morphologically different from chemically milled surfaces. This difference was found to contribute to Hirtisation® producing surfaces with higher roughness (Sa) than chemically milled surfaces at comparable removal depth. HIP did remove all detectable sub-surface defects but microstructural artefacts indicating healed porosity were found.

Surface morphology, roughness, and corrosion resistance of dental implants produced by additive manufacturing

Ti–6Al–4V alloy (ASTM F136) is the Ti alloy mainly used for machined dental and orthopedic implants. Additive manufacturing (AM) or additive layer manufacturing (ALM) is the industrial process name for 3D printing. The AM include some processes among them selective laser melting (SLM), and electron beam melting (EBM). The AM is used to make products with complex and customized geometries. However, these techniques have limitations in terms of surface finishing quality. Implants produced by AM have high roughness and the presence of partially unfused particles on the surface which decreases the reactions among the device and cells and proteins in the body environment. The objective of the present work is to compare the surface morphologies and corrosion resistance of machined and SLM Ti–6Al–4V samples before and after acid etching. The surface characterization was performed using scanning electron microscopy (SEM) and optical profilometry. The corrosion resistance was analyzed using open circuit potential (OCP), potentiodynamic polarization, chronoamperometry, and zero resistance amperometry. Galvanic corrosion of Ti–6Al–4V in contact with Co–Cr–Mo alloys was analyzed. The results showed that the presence of unfused particles on the Ti–6Al–4V SLM sample surface decreased the corrosion resistance. The hydrofluoric acid (HF) surface etching increased the corrosion resistance of the SLM samples. Ti–6Al–4V SLM treated with HF solution for 20 min showed the highest corrosion resistance and lowest roughness surface. After sanding, both machined and SLM Ti–6Al–4V samples showed similar corrosion resistance in the 0.9% NaCl electrolyte with and without fluoride.

Soft Microdenticles on Artificial Octopus Sucker Enable Extraordinary Adaptability and Wet Adhesion on Diverse Nonflat Surfaces (Adv. Sci. 31/2022)

Biomimetics In article number 2202978, Tae-Heon Yang, Changhyun Pang, and co-workers report a highly adaptive soft microstructured switchable adhesion device, which is inspired by the geometric and material characteristics of the tiny denticles on the surface of an octopus sucker. Owing to the presence of artificial microdenticles, the adhesive device demonstrates effective transport on soft, curved objects with high roughness in dry and wet conditions.

Effect of surface roughness on low-cycle fatigue behaviors of 316LN stainless steel in borated and lithiated high-temperature pressurized water

Low-cycle fatigue behaviors of 316LN stainless steel with three surface roughness were investigated in high-temperature pressurized water at different strain rates (0.001−0.04%/s) under strain amplitude of 0.3%. More significant reduction of fatigue life was found for samples with higher roughness. The environmental fatigue effects with different surface roughness were strain rate dependent and the weakened effect at low strain rates was related to the plastic deformation layers which enhanced the diffusion of Cr and played an inhibiting role on fatigue crack growth. Besides, the fatigue damage mechanisms for polished and rough samples are discussed.

Assessing the Efficacy of Whole-Body Titanium Dental Implant Surface Modifications in Inducing Adhesion, Proliferation, and Osteogenesis in Human Adipose Tissue Stem Cells.

Although the influence of titanium implants' micro-surface properties on titanium discs has been extensively investigated, the research has not taken into consideration their whole-body effect, which may be considered possible using a combinatorial approach. Five titanium dental implants with a similar moderate roughness and different surface textures were thoroughly characterized. The cell adhesion and proliferation were assessed after adipose-tissue-derived stem cells (ADSCs) were seeded on whole-body implants. The implants' inductive properties were assessed by evaluating the osteoblastic gene expression. The surface micro-topography was analyzed, showing that hydroxyapatite (HA)-blasted and bland acid etching implants had the highest roughness and a lower number of surface particles. Cell adhesion was observed after 24 h on all the implants, with the highest score registered for the HA-blasted and bland acid etching implants. Cell proliferation was observed only on the laser-treated and double-acid-etched surfaces. The ADSCs expressed collagen type I, osteonectin, and alkaline phosphatase on all the implant surfaces, with high levels on the HA-treated surfaces, which also triggered osteocalcin expression on day seven. The findings of this study show that the morphology and treatment of whole titanium dental implants, primarily HA-treated and bland acid etching implants, impact the adherence and activity of ADSCs in osteogenic differentiation in the absence of specific osteo-inductive signals.

Construction and anti-corrosion behavior study of silanol-modified Ni-WS2 superhydrophobic composite coating

In this study, a novel superhydrophobic composite coating is prepared by a two-step method. Firstly, the Ni-based deposition coating is fabricated via composite electrodeposition with WS2 granules worked as dispersed phase particles, and the roughness of deposit coating can be adjusted by changing the added amount of sulfide in the bath. The prepared Ni-WS2 deposit exhibits sufficiently high roughness and suitable micro-nano morphology. Then, hexadecyltrimethoxysilane (HDTMS) is used to modify the deposition coating with low surface energy to obtain silanol-modified Ni-WS2 coating with superhydrophobic properties. The superhydrophobic behavior of the composite coating conforms to the Cassie-Baxter model, with low adhesion to aqueous solutions. When the addition amount of WS2 particles in the plating solution during the electrodeposition process is 5 g·L−1, the prepared composite coating has the excellent superhydrophobic properties. The water contact angle of the composite coating is 154.7° ± 2 and the sliding angle can reach 6°. And the superhydrophobic composite coating exhibits excellent corrosion resistance.

The enhanced antibacterial effect of BNNS_Van@CS/MAO coating on Mg alloy for orthopedic applications

The development of multifunctional Mg-based active implants with controllable degradation and antibacterial capabilities has become a hotspot in the research field of biodegradable metallic materials. To this end, a BN nanosheets (BNNS) _vancomycin (Van) @chitosan (CS) nanocomposite coating containing two antibacterial components (BNNS and Van) was prepared on Mg alloys via a micro-arc oxidation (MAO) pre-treatment combined with following electrodeposition. The related characterizations of the coating show that the composite coating has a high roughness, hydrophobicity and fair corrosion resistance. In vitro antibacterial experiments show that the BNNS_Van@CS/MAO composite coating have obvious inhibitory effect on the growth of both E. coli and S. aureus. The antibacterial effect of the BNNS_Van@CS/MAO composite coating was attributed to the synergistic effect of CS, BNNS and Van. This study provides a valuable surface modification strategy for developing multifunctional Mg-based implants with good corrosion resistance and antibacterial properties.