Surface Function Research Articles

RETRACTED: Upper bound analysis of surrounding rock pressure in shallow buried unsymmetrical tunnels based on the Hoke-Brown criterion

This article has been retracted. A retraction notice can be found at https://doi.org/10.3233/JIFS-219433.

Synthesis, topology, molecular docking and dynamics studies of o-phenylenediamine derivative

The N, N’-(1,2-phenylene) bis (1- (4- chlorophenyl) methanimine) (CS4) was synthesized and characterized by infrared (IR), absorption (UV-vis) and NMR (1H and 13C) spectral analyses. The structural parameters, vibrational frequencies, potential energy and the distribution analysis (PED) were calculated by using DFT with the basis set of B3LYP/cc-pVDZ and these spectral values were compared to the experimental values. HOMO and LUMO studied were performed in order to understand the stability and biological activity of the compound. The most reactive sites on the compound were investigated by utilizing MEP energy surface and Fukui function descriptor with the natural population analysis (NPA) of the charges. The study of the natural bond orbitals (NBO) reveals the delocalization of the intramolecular interaction of the charges in the compound. Additionally, topological investigations (ELF, LOL), determination of thermodynamic parameters and noncovalent interaction (NCI) study by using topology (RDG) analysis were also carried out. Finally, the molecular docking and molecular dynamics simulations was carried out by examining against glycosylphosphatidylinositol phospholipase D inhibitor receptor for distinct protein targets (3MZG). Communicated by Ramaswamy H. Sarma

Evaluation of dry eye disease and corneal epithelial mapping in patients with lower eyelid ectropion.

To evaluate the corneal epithelial mapping, ocular surface parameters and their relationship with each other in lower eyelid ectropion patients according to severity. This retrospective study included 48 lower eyelid ectropion patients and 63 healthy individuals as control group. Ocular surface and tear functions were evaluated with ocular surface staining score, tear film break-up time (BUT), non-invasive tear break-up time (NIBUT) and ocular surface disease index (OSDI). Meibography scores and corneal epithelial thickness (CET) mapping were evaluated. The lower eyelid ectropion was classified and divided into subgroups as follows: mild, moderate and severe. There was no significant differences between the groups for age and gender. Compared to controls, CET was significantly thinner at inferior (p = 0.047) and inferior nasal quadrants (p = 0.023) in the ectropion patients. Lower BUT and NIBUT, higher OSDI scores and higher ocular surface staining were observed in the ectropion patients. In the subgroups determined according to the severity of ectropion, ocular surface damage was found to be significantly higher as the severity of ectropion increased (p < 0.05). Patients with lower eyelid ectropion had worse ocular surface findings and more ocular complaints. Furthermore, the inferior and inferior nasal CETs were thinner in patients with lower ectropion.

Efficacy of the combination of cyclosporine and sodium hyaluronate eye drops on dry eye syndrome

Purpose: To investigate the efficacy and adverse effect of cyclosporine combined with sodiumhyaluronate (SH) eye drops on dry eye syndrome (DES).Methods: 148 patients with DES treated in Nanjing Drum Tower Hospital Group Suqian Hospital,Jiangsu Province, China between January 2022 and February 2023 were randomly assigned to control(70 cases) and study groups (78 cases). Control group was treated with SH eye drop (1 drop each onboth eyes 5 - 6 times a day, for 2 months), while study group was treated with both SH (the samedosage and use with control group) and cyclosporine eye drop (1 - 2 drops each for both eyes, 4 - 6times a day, for two months). Tear film stability indices such as schirmer I test (SIT), tear break-up time(BUT) and corneal fluorescein stain (FL) of both groups were analyzed before and after therapy.Results: There was no significant difference in BUT, SIT and FL score between the two groups beforetreatment. Compared with before treatment, BUT and SIT increased significantly (p &lt; 0.05), while FLscore dropped significantly in both groups after treatment (p &lt; 0.05). After treatment, study groupshowed significantly higher BUT and SIT levels, and significantly lower FL score than control group (p &lt;0.05).Conclusion: The combination of cyclosporine eye drops with SH eye drops is effective in treating DES.This combination regimen protects tear film stability, effectively alleviates DES symptoms, improvesocular surface and meibomian gland function, and also increases lacrimal river height, withoutincreasing adverse reactions. Further studies will be required, to provide more evidence for clinicalapplication of this combination regimen.

Amplitude methods for forming frequency-independent radiation characteristics of multibeam reflector antennas

The trend towards expanding the operating frequency ranges of radio-electronic equipment has led to an increasing interest in recent years in the study of ways to constructing multi-beam frequency-independent reflector antennas, which requires systematization of the principles and methods of their construction. When constructing reflector antennas, methods based on the selection of the directional properties of the feeds and methods based on the selection of the frequency-selective properties of the reflectors are used. Methods based on the choice of directional properties of feeds are divided into methods using horn feeds and methods using feeds in the form of cluster arrays with intersecting apertures. Horn feeds are used to create single-beam reflector antennas. Using cluster arrays, it is possible to form a plurality of beams of frequency-independent partial radiation patterns. Using the example of a hybrid reflector antenna, the possibility of forming nine beams in the azimuthal sector of 20° with a beam width of 3.2° ± 0.45° in the frequency band from 2 to 8 GHz is shown. The level of side lobes outside the working sector in the operating frequency band does not exceed –35 dB, the slope of the direction-finding characteristics varies from 4.8 to 9.8 dB/deg. Among the methods based on the choice of selective properties of reflectors, there are methods using frequency-selective surfaces and methods using corrective coatings on the working surface of the reflector. Frequency-selective surfaces are made in the form of wire meshes with variable pitch, in the form of a set of parabolic plates and in the form of a set of square waveguides with a side size ranging from half-wave at the upper frequency in the middle part of the reflector to half-wave at the lower operating frequency at the edges of the reflector. The disadvantages of using frequency-selective surfaces are the complex and expensive design of the reflector, low antenna efficiency, high side lobes and the need to use a large absorbing screen. When implementing the method using corrective coatings, the separate functions of a frequency-selective surface and a radio-absorbing screen are combined in one structural element – a frequency-dependent corrective coating applied to the working surface of the reflector. Among the advantages of this method, it is worth noting the simple design of the reflector and the possibility of its operation at any polarization, since the reflection characteristics of the coating are practically independent of the type of polarization. A common disadvantage of reflector antennas based on the choice of frequency-selective properties of reflectors is distortion of the shape of the main lobe of partial patterns and a larger range of scatter in the pattern width in the operating frequency band, which prevents the formation of linear direction-finding characteristics and reduces direction-finding accuracy. Due to the low efficiency of multibeam mirror antennas built using amplitude methods for forming frequency-independent radiation characteristics, their use as transmitting antennas is impractical. The completed review and identified features of methods for constructing frequency-independent radiation characteristics can become a methodological basis for the design of broadband multi-beam reflector antenna systems for advanced radio-electronic equipment.

Sliding mode variable structure control of RP manipulator based on computational torque

Study the control problem of a coupled robotic arm with moving and rotating joints, a PID control method based on calculated torque is proposed. Considering that the robot model is difficult to obtain accurately, only its estimation model can be obtained. The output feedback signal is used to define the sliding mode surface function with error signal. Sliding mode variable structure controller(SMVSC) is designed based on the computational torque control method. Taking the mathematical model of RP robot as an example, Experimental calculations have found that the control accuracy can be guaranteed, but there is a significant chattering situation. In engineering practice, it is necessary to process the symbol function.

On the ionic conductivity and mechanical behavior of cellulose-based electrolytes: Applications for rechargeable batteries

Our paper presents two approaches that are potentially industrially scalable to prepare polymer electrolytes for the development of next-generation rechargeable batteries involving new atoms like Na, Zn or Mg: (1) gel polymer electrolytes, GPE, and (2) solid polymer electrolytes, SPE. Cellulose nanocrystals (CNC) are used with different surface functions, surface charge and concentrations as a functional component in both systems. Systematic testing of their ionic conductivity as well as their dynamic mechanical behavior, which is critical for creating mechanically durable systems, has been performed. Higher ionic conductivity reaching up to 2.60 ± 0.57 mS/cm was obtained for cellulose based GPE, which is more than double the ionic conductivity tested for non-renewable Celgard® 2400 (1.15 ± 0.06 mS/cm). Whereas cellulose based SPE showed an ionic conductivity of up to 2.34 ± 0.28 × 10−6 S/cm, and in both systems, tailoring the surface charge on CNC surfaces significantly influenced the counterion mobility thereby improving the ionic conductivity.

Study on Plastic Deformation Removal Mechanism and Dislocation Change in Nanogrinding of Single Crystal Silicon Carbide with Random Rough Surface

This investigation centers on exploring the plastic deformation removal mechanism and dislocation dynamics in the nanogrinding of single‐crystal silicon carbide featuring a randomly rough surface. To simulate this, an approach combining the Weierstrass–Mandelbrot fractal surface function with molecular dynamics is employed. Randomly rough surface contours are generated using the Weierstrass–Mandelbrot fractal surface function. By adjusting the fractal dimension, an ideal representation of single‐crystal silicon carbide with randomly rough surfaces is obtained. By combining plastic deformation detection methods, the process of workpiece sliding, plowing, and chip removal is studied, and the plastic deformation removal mechanism of random rough surface grinding is explored. Combining postprocessing methods such as sheer strain and dislocation trajectory, the morphological changes and transformation mechanisms of dislocations are analyzed. Notably, at grinding depth of 33.18 nm, the activation of slip systems induces dislocation formation, enabling plastic deformation. Furthermore, at depths exceeding 144.00‐nm, the emergence of stacking faults on the random rough surface is observed. Throughout the grinding procedure, plastic deformation of debris occurs, leading to the formation of plastic bulges on both sides of the tool, and the debris generated during processing does not impact the defects encountered during secondary grinding of the rough surface.

RECONSTRUCTION OF THE CORNEAL SURFACE OF THE HUMAN EYE USING A COMPUTATIONAL EVOLUTIONARY ALGORITHM. PRACTICAL APPLICATION IN NON-PATHOLOGICAL CASES

Increasingly, the use of geometric modelling techniques in Applied Ophthalmology is significant in the characterization of important pathologies of the cornea, such as Keratoconus. This article presents a novel method for the geometric reconstruction of the corneal surface from optical topography using a genetic algorithm. Traditionally, mathematical programming methods such as the least squares method have been used to obtain the coefficients of the corneal surface function, such as Navarro model or Zernike polynomials. This new method uses non-dominated multivariable genetic algorithm optimization to obtain the surface function coefficients from the point cloud obtained with corneal topographer device. Once the reconstruction is performed, the surface is represented using CAD software, and morphogeometric parameters are obtained. The experimental sample consisted in 33 healthy patients eyes, aged from 11 to 63, and without previous ocular surgeries or pathologies. Topographic data were obtained using a Scheimpflug Sirius tomographer (CSO, Italy). The computational optimization was executed under Matlab software environment (Mathworks, USA). The new method provides a lower mean squared error (MSE) than those obtained by the least squares or the nonlinear programming algorithms. Thus, the morphogeometric parameters obtained from the patient's corneas fit better, allowing for a better analysis of real clinical conditions.

Adhesion Reduction in Plastics Processing by means of laser-generated Microstructuring

Almost all production processes for manufacturing plastic or fiber reinforced plastic (FRP) components have in common that plastic and a steel surface are pressed together in the process. To avoid adhesion, the steel belts are coated with polytetrafluoroethylene (PTFE), ceramics or perfluoroalkoxy (PFA) during calendering, for example. However, the high temperatures of over 250 °C and the alternating mechanical load lead to damage of the coating. This results in adhesion of the coating to the product and loosening of the coating. Due to this, the surface quality of the organic sheets is reduced, and the production process is negatively affected.As the surface function can be controlled by material and surface patterns with different length scales (nm - µm), the surface topography of the belt steel was specifically modified in the roughness and microstructure level in order to reduce the adhesive interaction with the organic sheet. These microstructures were tested in extensive experiments and the results will be presented in this publication. True to the motto from nature to innovation, the micro- and nanostructured surface of the lotus leaf, which is provided with a fine substructure, was used as reference. The aim was to generate such a hierarchical structure by means of direct laser writing in order to avoid adhesions on production surfaces and to substitute the coating of steel strip surfaces. Additionally, a testing method close to the process was developed and evaluated to test the laser structured microstructures, which will also be presented.

A REVIEW ON FABRICATION TYPES OF MICRO/NANO HIERARCHICAL STRUCTURES AND THEIR APPLICATIONS IN AEROSPACE ENGINEERING

This review paper discusses various nano/microstructures and fabrication techniques. The nano/ microstructure materials like nano/micropatterned polymer and hierarchical structured surfaces employ different fabrication processes which is the main purpose of this review paper to identify the best technique for Aerospace applications.. The common nano/micro patterned polymer surfaces fabrication technique is by using soft lithography. Hierarchical structured surfaces fabrication techniques are by using soft lithography, self-assembly and by drag reduction from shark skin. They have a special and excellent surface functions namely hydrophobicity, structure color, drag reduction, anti-adhesion, color camouflages and other features. Super hydrophobic surfaces are used for various applications, such as solar panels, cutlery, roof tiles, fabrics, self-cleaning windows, windshields, buildings paints, external paints for ships and others. The main applications in aerospace are the airfoil design, self-cleaning window glasses or paints and anti-corrosion metal surfaces. The methods employed to arrive on our specific applications are description on nano/micro hierarchical structures, useful natural replicas for these strictures, identifying their surface functions and unique benefits as well as the recommended fabrication processes and applications. The best application we found is the riblet fabrication used in airplanes and airfoils geometries. These hierarchical structured surfaces are fabricated by drag reduction from shark skin.

Recent Patents on Manufacturing Microtextured Surface

Background: Surface microtextured technology is an expansion and extension of biomimicry in the tribology field, promoting vigorous development in microtextured tribology. Through artificial means, tiny convex hulls, craters, or stripes of specific size and arrangement are processed on the friction surfaces to change the morphology and contact angle of the surfaces and improve the surface contact state or the lubrication effect. The function and properties of microtextured surfaces are determined by optimizing their geometrical parameters, but the microtextured geometrical parameters require a high-level machining quality. It is necessary to analyze and summarize the existing research on manufacturing microtextured surfaces. By summarizing the preparation methods of microtextured surfaces in the past decade, some valuable conclusions are drawn to predict the future development of technology for manufacturing microtextured surfaces and provide a reference for researchers in related fields. This paper summarizes the representative patents related to the methods of manufacturing microtextured surfaces, analyzes the properties of the microtextured surfaces produced by each method, and discusses the advantages and disadvantages of these methods. The existing problems are summarised through the analyses of patents related to microtextured preparation methods. The future development of new preparation methods has prospected. By cooperating with various processing technologies and optimizing the processing methods, the microtextured surfaces can meet various functional requirements, and the manufacturing precision is higher than before. The processing method needs further improvement according to the working conditions. More new technologies will be invented to create microtextured surfaces.

Ultra-low work function of caesiated surfaces and impact of selected gas species

Modern high-power negative hydrogen ion sources rely predominantly on the surface production of negative hydrogen ions. Hence, low work function converter surfaces are mandatory, for which the alkali metal Cs is commonly evaporated into the ion source to lower the work function of refractory metals by surface adsorption. To study the work function behaviour upon caesiation under the typically given non-ultra-high vacuum conditions, investigations are performed at a dedicated laboratory experiment. In a vacuum environment dominated by water vapour, the work function evolution is found to be dependent on the flux ratio of Cs to H2O onto the surface. For sufficiently high flux ratios, ultra-low work functions in the range of 1.25±0.10 eV are generated with excellent reproducibility. In the absence of Cs evaporation, the work function gradually increases under the influence of the residual gases, and re-caesiation processes lead to lower quantum efficiencies and higher work functions of typically 1.9–2.1 eV. While the addition of hydrogen and deuterium gas at several Pa as well as the leakage of inert gases (argon and nitrogen) into the vacuum system have a negligible influence on the caesiation process, small amounts of oxygen with partial pressures of ∼10-2–10-1 Pa lead to an instant reduction of the Cs density in the gas phase by several orders of magnitude and to an increase in the work function of the order of 1 eV. After the oxygen exposure is terminated, however, the Cs density and work function fully recover within several minutes.

The uniformly continuous theorem of fractal interpolation surface function and its proof

&lt;abstract&gt; &lt;p&gt;In order to research uniform continuity of fractal interpolation surface function on a closed rectangular area, the accumulation principle was applied to prove uniform continuity of fractal interpolation surface function on a closed rectangular area. First, fractal interpolation surface function was constructed by affine mapping. Second, the continuous concept of fractal interpolation surface function at a planar point in a three-dimensional cartesian coordinate space system and uniform continuity of fractal interpolation surface function on a closed rectangular area were defined in the paper. Finally, the uniformly continuous theorem of fractal interpolation surface function was proven through accumulation principle in the paper. The conclusion showed that fractal interpolation surface was uniformly continuous function on a closed rectangular area.&lt;/p&gt; &lt;/abstract&gt;

High-fidelity synthesis of microhole templates with low-surface-energy-enabled self-releasing photolithography.

Material patterning through templates has provided an efficient way to meet the critical requirement for surface function in various fields. Here, we develop a self-releasing photolithographic process to make large-area freestanding templates with precise patterns. The low surface energy of substrates by hydrophobic treatment with proper silane modification ensures the template self-releasing. This method eliminates the need of mechanical separation or any sacrificial layers. Major steps including UV exposure and baking are optimized to realize high-quality structures and the final release of templates. The negative photoresists of SU-8 and polyimide are chosen to confirm the feasibility of this process. Wafer-scale freestanding templates with uniform microhole arrays are obtained with high structural fidelity, smooth surfaces and excellent flexibility. The hole size ranges from several to several tens of micrometers with an extremely low variation (<1%). These advantages could promote the application of precisely structured templates for surface patterning in material and surface science.

Porous Metallic Implants from Additive Manufacturing to Biocorrosion: A Review

The improved bulk and surface function of manufactured implants has advanced implantation procedures, leading to a decline in surgical risks. Many current techniques discussed in the literature are related to additive manufacturing (AM) of lightweight implants based on reliable, precise, flexible scaffolds and capable of mimicking bone properties while incorporating other useful features. These techniques have evolved for the production of a variety of biocompatible materials. AM has progressed beyond prototype to full-scale manufacturing of metals, polymers and ceramic products. However, metallic implants often fail in vivo due to biocorrosion and deterioration, limiting implant longevity. This study reviews current trends and approaches to enhancing the surface corrosion resistance of porous metallic implants and the effect of interfacial films on biological activity. The art of porous metallic implants manufactured by AM and their biocorrosion behaviour are discussed. This review also evaluates future trends and perspectives in additively manufactured synthetic orthopaedic implants porous with enhanced surface morphology.

Envisioning the future: optically transparent metasurface-based solar thermophotovoltaic with high conversion efficiency

Transparent solar thermo-photovoltaic (TPV) technology combines visible transparency and solar energy conversion. They are developed for their potential applications in buildings and vehicles windows, where conventional opaque solar cells may not be feasible. TPV’s offer a promising solution to harness solar energy without compromising aesthetics or functionality of transparent surfaces. Broadband absorption at UV and IR frequencies and simultaneous transmission at visible frequencies can be achieved by fabricating metamaterials that employ semi-conducting oxides. In this study, an optically transparent metasurface (OTM) based STPV composed of indium tin oxide (ITO) is introduced as the transparent metal and ZnS as a substrate layer. Our design offers a cost-effective and scalable solution for large-scale fabrication. The designed OTM structure exhibits exceptional absorption capabilities, achieving an absorption rate of up to 99% in the UV region. Additionally, it achieves over 90% absorptivity in the far infrared range and maintains a high average transmittance at visible frequencies. Furthermore, the absorption remains consistently high, exceeding 90%, even when the incident angle is less than 70° for both TE and TM polarization waves. This innovative design holds promise for various applications requiring high-performance transparent metasurface absorbers/emitters. The proposed transparent metasurface based STPV holds great potential for efficient utilization in combined solar/thermal conversion systems.

Aerosol retrieval over snow using the RemoTAP algorithm

Abstract. In order to conduct accurate aerosol retrieval over snow, the Remote Sensing of Trace Gases and Aerosol Products (RemoTAP) algorithm developed by SRON Netherlands Institute for Space Research is extended with a bi-directional reflection distribution function (BRDF) for snow surfaces. The capability of the extended algorithm is validated with both synthetic measurements and real satellite measurements from the Polarization &amp;amp; Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar (PARASOL), and a comparison has been made to retrievals with the baseline RemoTAP (without a snow kernel). For retrievals with real PARASOL observations, we use pixels over Aerosol Robotic Network (AERONET) stations for validation and we use the MODIS snow cover products to identify pixels over snow. We evaluate the retrieved aerosol optical thickness (AOT) at 550 nm (τ550), single-scattering albedo (SSA) at 550 nm (ω550) and Ångström exponent (AE) for 440–870 nm (AE440−870). The experiments with both synthetic and real data show that the extended RemoTAP maintains capability for snow-free pixels and has obvious advantages in accuracy and the fraction of successful retrievals for retrieval over snow, especially over surfaces with snow cover &gt;75 %. According to the real-data experiment, we find that the retrieval algorithm has difficulty in fitting the PARASOL 1020 nm band, where snow reflectance is significantly lower than that for the visible bands. When we perform a four-band retrieval (490, 565, 670, 865 nm) with the extended RemoTAP, we obtain a good retrieval result for τ550, ω550 and AE440−870. Therefore, the four-band retrieval with the extended RemoTAP is recommended for aerosol retrieval over snow.

Seasonality in land-ocean connectivity and local processes control sediment bacterial community structure and function in a High Arctic tidal flat.

Climate change is altering patterns of precipitation, cryosphere thaw, and land-ocean influxes, affecting understudied Arctic estuarine tidal flats. These transitional zones between terrestrial and marine systems are hotspots for biogeochemical cycling, often driven by microbial processes. We investigated surface sediment bacterial community composition and function from May to September along a river-intertidal-subtidal-fjord gradient. We paired metabarcoding of in situ communities with in vitro carbon-source utilization assays. Bacterial communities differed in space and time, alongside varying environmental conditions driven by local seasonal processes and riverine inputs, with salinity emerging as the dominant structuring factor. Terrestrial and riverine taxa were found throughout the system, likely transported with runoff. In vitro assays revealed sediment bacteria utilized a broader range of organic matter substrates when incubated in fresh and brackish water compared to marine water. These results highlight the importance of salinity for ecosystem processes in these dynamic tidal flats, with the highest potential for utilization of terrestrially derived organic matter likely limited to tidal flat areas (and times) where sediments are permeated by freshwater. Our results demonstrate that intertidal flats must be included in future studies on impacts of increased riverine discharge and transport of terrestrial organic matter on coastal carbon cycling in a warming Arctic.

Application of Profilometric Measurements in an Assessment of Woven Fabrics Surface Geometry

ABSTRACT The surface roughness of the textile materials is one of the crucial features influencing the appearance and functionality of fabrics and products made of them. The surface roughness of textile materials can be measured using the contact or non-contact methods. In the presented work, the non-contact method using the MicroSpy® Profile profilometer was applied to assess the quality of surface of the cotton woven fabrics of plain and 3/1S twill weave. Determination of surface geometry parameters and functions was done using the Mark III software according to the DIN EN ISO 4287 standard. Results showed that the twill woven fabric is characterized by greater roughness than the plain woven fabric. The profiles created along the warp and weft have different shapes dependably on fabric weave. The autocorrelation function reflects the weave pattern of the woven fabrics. Performed investigations confirmed that the non-contact method of measurement of fabric surface geometry by means of the profilometer provides very detailed and complex data about the fabrics’ surface quality.