Surface Parameters Research Articles

The Effect of Varying Parameters of Laser Surface Alloying Post-Treatment on the Microstructure and Hardness of Additively Manufactured 17-4PH Stainless Steel

The Effect of Varying Parameters of Laser Surface Alloying Post-Treatment on the Microstructure and Hardness of Additively Manufactured 17-4PH Stainless Steel

Atomic Layer Growth of Rutile TiO2 Films with Ultrahigh Dielectric Constants via Crystal Orientation Engineering.

In general, the electronic and optical properties of oxide films can significantly benefit from highly textured crystallinity. However, oxide films grown by atomic layer deposition (ALD), a powerful technique for the synthesis of high-quality, nanoscale thin films, usually exhibit amorphous or randomly oriented polycrystalline phases. Here, we demonstrate the growth of highly textured rutile phase ALD TiO2 films through rational substrate design. Both a- and c-axis preferentially oriented TiO2 films are obtained by varying the lattice parameters of the initial ALD growth surface. Under optimized conditions, we find that it is possible to deposit high-quality, c-axis preferentially aligned TiO2 films with a bulk dielectric constant approaching 185, rivaling the single crystal limit. These films display a remarkably high dielectric constant of 117 despite thin thickness of 5.2 nm. Moreover, the addition of a single doping sequence of Al2O3 successfully suppresses leakage currents to levels compatible with modern dynamic random access memory cells, all the while maintaining the high bulk dielectric constant of 137. These results clearly highlight the prospect of utilizing crystal orientation engineering in ALD thin films for emerging semiconductor devices.

Surface parameterisation and spectral synthesis of rapidly rotating stars. Vega as a testbed

Spectral synthesis is a powerful tool with which to find the fundamental parameters of stars. Models are usually restricted to single values of temperature and gravity, and assume spherical symmetry. This approximation breaks down for rapidly rotating stars. This paper presents a joint formalism to allow a computation of the stellar structure — namely, the photospheric radius, $R$, the effective temperature, $T_ eff $, and gravity, $g_ eff $ — as a function of the colatitude, theta , for rapid rotators with radiative envelopes, and a subsequent method to build the corresponding synthetic spectrum. The structure of the star is computed using a semi-analytical approach, which is easy to implement from a computational point of view and which reproduces very accurately the results of much more complex codes. Once $R( eff and eff are computed, the suite of codes atlas and synthe by R. Kurucz are used to synthesise spectra for a mesh of cells in which the star is divided. The appropriate limb-darkening coefficients are also computed, and the final output spectrum is built for a given inclination of the rotation axis with respect to the line of sight. All the geometrical transformations required are described in detail. The combined formalism has been applied to Vega, a rapidly rotating star almost seen pole-on, as a testbed. The structure reproduces the results from interferometric studies and the synthetic spectrum matches the peculiar shape of the spectral lines well. Contexts where this formalism can be applied are outlined in the final sections.

Changes in Ocular Surface Status after 25-gauge Pars Plana Vitrectomy

Purpose: We used a noninvasive ocular surface analyzer to explore changes in the ocular surface parameters of patients who underwent 25-gauge pars plana vitrectomy (PPV).Methods: The medical records of 82 patients (163 eyes) who underwent PPV were retrospectively reviewed. The non-invasive tear film break-up time (NIBUT), the lipid layer thickness, meibomian gland loss status, and the tear meniscus height were measured before, and 1 and 3 months after treatment. Consecutive changes in the ocular surface indices of operative and non-operative fellow eyes were statistically compared. Also, factors that reduced the NIBUT at 1 month after surgery were analyzed.Results: One month after surgery, the NIBUT was significantly decreased in the operative group compared to before surgery (<i>p</i> = 0.006). Compared to non-operative eyes, the NIBUT of operative eyes decreased significantly 1 month after surgery (<i>p</i> = 0.003). Older age and lower preoperative NIBUT (<i>p</i> = 0.029, <i>p</i> = 0.002) were significantly associated with lower NIBUT 1 month after surgery.Conclusions: Twenty-five gauge PPV significantly reduces the NIBUT 1 month after surgery.

Systematic review of ocular surface treatments in the setting of thyroid eye disease.

Approximately 85% of patients with thyroid eye disease experience ocular surface symptoms. Although corneal exposure plays a role in inducing inflammatory changes to the ocular surface, multiple studies reveal more complexity to the abnormal tear film composition and parameters in thyroid eye disease patients including those who do not have proptosis or increased corneal exposure. Currently, a majority of cases of thyroid associated dry eye symptoms are given treatments intended for ocular surface disease arising from different etiologies. Medline via Ovid, Cochrane CENTRAL, PubMed, and Google Scholar were systematically searched for articles evaluating the efficacy of treatments for dry eye symptoms in patients with thyroid eye disease. Articles were from all geographic regions and dates ranged from inception until October 2023. Seven papers ultimately met inclusion criteria and were included in this review. These papers revealed that multiple topical and non-topical treatment modalities address dry eye symptoms in thyroid eye disease and improve subjective and objective ocular surface parameters. However, due to the few studies that exist and due to disparities in sample size and study design, no overwhelming best practices were identified that could influence clinical practice. This systematic review identifies the current treatments that exist and highlights the clear unmet need for a large population suffering with dry eye symptoms. Ideally, further well-designed investigations into this area would target topical, non-invasive modalities to develop first line options for thyroid eye disease patients.

Use of Heat-Applied Coatings to Reduce Wear on Agricultural Machinery Components

This article presents the effect of the conditions of abrasive compounds on the wear of samples made by different methods. The 28MnB5 steel was used, which is intended for agricultural components, to which two arc and laser coatings were applied. The study included the analysis of microstructure, microhardness, roughness, and tribological experiments on a dedicated stand. The arc coating was found to significantly improve the tribological properties compared to the samples without the coating. Varied wear results were obtained for the laser coating depending on the parameters of the abrasive compound. Studies of the surface roughness of the samples showed that the concentration and pH of the abrasives have a significant effect on the changes in the surface parameters after the tribological tests. The results of the tribological experiments indicated that wear resistance for some of the abrasive mass conditions was improved by the application of heat-applied coatings. In addition, it was found that the power consumption on the stand was the highest for abrasive mass conditions of a 10% moisture content and a pH of 10. For these test conditions, the mass loss was four times higher than for the parameter with W0% and pH7. The energy consumption of the stand was 60 kWh lower for this variant than for the parameter with W10% and pH10. The results of the study have important practical applications that can help in the selection of materials for agricultural machinery components, depending on the abrasive mass conditions.

Multimedia Photogrammetry with non-planar Water Surfaces – Accuracy Analysis on Simulation Basis

Abstract. If multimedia-photogrammetry is used for the generation of point clouds of submerged objects or of the water bottom, Snell’s law has to be considered. When the images are taken from air, image rays are refracted at the air-water interface. This results in the collinearity equations being no longer valid. Bundle block adjustment can still be solved by adding additional terms considering Snell’s law. Existing approaches usually assume that the water surface is flat. Refractive indices and water height can either be measured separately or included as unknowns in the adjustment. However, when the water surface is not flat due to the presence of waves, assuming a planar water surface leads to large geometric errors. This work will analyze the significance of those errors and propose a way of including water surface parameters as unknowns into the bundle block adjustment, both based on simulated data. The simulation reproduces multiple images taken simultaneously, e.g. from synchronized UAV cameras or from cameras on tripods.

The influence mechanism of bitumen components on its macroscopic and microscopic properties: Analysis based on polyphosphoric acid modification

In order to investigate the impact of bitumen components on its overall properties, various modified bitumen with 1.0 %PPA or 2.0 %SBS/SBR + 0.6 %PPA were prepared. The influence of PPA dosage on bitumen’s physical properties were evaluated, and the macroscopic and microscopic properties of each bitumen sample were characterized by DSR, BBR and atomic force microscopy observation. The components of bitumen were separated through SARA test, and the infrared spectroscopy of asphaltenes was further analyzed. The findings suggest a significant impact on bitumen with PPA incorporation, the elastic recovery properties of bitumen at high temperatures were enhanced due to a more stable colloidal structure was formed by the dispersion and interaction of macromolecular asphaltenes. However, the low-temperature rheological properties of bitumen were impaired by reason of a relatively reduced flowable lightweight component. Specifically, the large asphaltenes clusters were dispersed cause PPA reacted with the –OH bonds of alcohols in bitumen by phosphorylation. By modeling the correlation between bitumen component contents and its microscopic surface parameters, the asphaltenes decomposition was demonstrated to be an important factor on the microscopic morphology, which was also related to the content of saturates and aromatics. Thus, a method for deconstructing bitumen from a compositional perspective is proposed.

Machine learning in prediction of residual stress in laser shock peening for maximizing residual compressive stress formation

Laser Shock Peening (LSP) is an advanced technique for enhancing surface properties, drawing significant interest for its ability to induce beneficial residual stresses in materials. Traditional LSP design processes, reliant on manual parameter selection, often result in imprecise control over the stress distribution, necessitating multiple iterations and high costs. This study introduces a machine learning (ML)-based approach, utilizing the Random Forest (RF) algorithm, to automate and optimize the design of LSP parameters for nickel-aluminium bronze surfaces. Our findings demonstrate the RF model’s capability to accurately predict and optimize residual stress distributions, achieving compressive stresses up to 472 MPa with a notable reduction in design iterations. The model forecasts both uniform and non-uniform stress patterns, particularly identifying areas susceptible to Residual Stress Holes (RSH) with improved precision. With an Absolute Percentage Error (APE) of only 6.2 %, our approach significantly outperforms traditional ML algorithms, offering a novel method for efficiently designing complex residual stress fields in LSP applications.

Analysis of Geochemical Parameters for Surface and Groundwater in Zuru Local Government Area of Kebbi State, Nigeria

Study’s Excerpt/Novelty• This study provides novel insights into the geochemical parameters of surface and groundwater in Zuru, Kebbi State, revealing significant differences in water quality. • By systematically comparing these values against WHO standards, the research identifies groundwater as more suitable for consumption and domestic use. • This comparative analysis offers new, region-specific data that contributes to the understanding of water quality in southern Kebbi State, addressing a critical gap in localized environmental health research. Full Abstract As one of the fundamental elements of life, living nature could not survive without water. Contaminated water consumption can lead to water-borne diseases and can also cause gastrointestinal illnesses, nervous system illnesses, reproductive effects, and chronic diseases such as cancer. In this study, some geochemical parameters were analysed for surface and undergroundwater around Zuru in southern part of Kebbi state. The result was compared with WHO's prescribed standard for quality water consumption. Four samples of each surface and groundwater were collected from various geographical locations within Zuru for analyses to determine density, conductivity, total hardness, calcium (Ca2+) hardness, magnesium (Mg2+) hardness, pH, and total dissolved solids (TDS) by employing scientific and technological approaches. Surface water has higher values for mean total hardness (93.8 mg/L), the average value for calcium (62.0 mg/L), magnesium (Mg2+) hardness (44.0 mg/L), and the mean value for total dissolved solids (TDS) (620 mg/L), while groundwater has lower values for mean total hardness (30.0 mg/L), the average value for calcium (26.0 mg/L), magnesium (Mg2+) hardness (17.0 mg/L) and mean value for total dissolved solids (TDS) (564.5 mg/L). Groundwater has higher values of average density (0.92 g/cm3), conductivity (114.3µS/cm), and average pH level (7.0), while surface water has lower values of average density for (0.90 g/cm3), conductivity (76.1µS/cm), and average pH level (6.9). The research has shown that groundwater is favourably more recommended for drinking and other domestic usages.

Spatial and Temporal Variations in Land Surface Temperature as an Indicator of Learning Comfort Level in Banten Province

Increasing population and rapid development of built-up land can cause an increase in land surface temperature. These changes are often associated with many factors, including changes in land use, and surface parameters, economic development, and vegetation. This research aims to analyze the temperature factor as an indicator of indoor thermal comfort to support the learning process in schools in the Banten Province area. This research uses a spatial temporal approach with descriptive statistical analysis. Based on the results, show that the land surface temperature at each school location in Banten province shows conditions that are not constant. The number of schools with uncomfortable conditions varies from 2019 (89.07%), 2020 (42.65%), 2021 (45.66%), 2022 (82.66%), and 2023 (52.44%). This shows that there has been a decrease in uncomfortable conditions for studying by 36.63% in the last 5 years.

Comparison of autologous serum and platelet-rich plasma in the treatment of severe dry eye and persistent epithelial defects

PurposeTo compare the efficacy of topical autologous serum and platelet-rich plasma (PRP) in patients with severe dry eye and persistent epithelial defects. MethodsSixty-seven eyes of 42 patients including 12 Sjogren, 11 meibomian gland dysfunction, 8 post penetrating keratoplasty, 5 acne rosacea, 5 chemical burn and 3 neurotophic keratopathy were analyzed. Best corrected visual acuity, Schirmer, Ocular Surface Disease Index (OSDI), tear break-up time, Oxford staining scores were measured before the treatment and 1 month. One month scores of two groups were compared. ResultsThirty three eyes received autologous serum and 34 received PRP. There was no statistically significant differences between two groups in ocular surface parameters at baseline. Statistically significant improvements were achieved in both groups in all parameters at 1 month (p < 0.05). Schirmer score improved from 7.9 ± 7.6 to 10.6 ± 8.4 mm in autologous serum (p < 0.001) and from 10.9 ± 9.5 to 13.3 ± 10.1 in PRP (p < 0.001); BUT from 4.3 ± 2.7 to 6.7 ± 3.4 s (p < 0.001) and 4.5 ± 3.0 to 6.0 ± 3.6 (p < 0.001); OSDI from 47.7 ± 14.7 to 25.7 ± 11.0 (p < 0.001) and from 54.1 ± 17.3 to 26.8 ± 11.0 (p < 0.001); Oxford score from 4.0 ± 1.0 to 1.3 ± 1.1 in (p < 0.001) and 3.9 ± 0.9 to 1.6 ± 1.3 (p < 0.001) respectively. Significant visual improvement was achieved with PRP from 0.81 ± 0.73 LogMAR to 0.72 ± 0.63 (p = 0.025), whereas insignificant with serum from 0.60 ± 0.65 to 0.57 ± 0.67 (p = 0.147). Mean epithelial healing time was 6.7 ± 4.7 (2–14) days in serum and 3.6 ± 1.9 (2–7) in PRP (p = 0.195). ConclusionsBoth treatments are equally effective in severe dry eye and persistent epithelial defects. Although, visual gain is higher in PRP, autologous serum may be preferable due to low cost.

Effect of nitrogen/oxygen ratios on surface charge distributions generated by repetitive surface dielectric barrier discharges

Studies on the dielectric surface parameters and dielectric barrier discharges (DBD) characteristics considering the influence of gases in DBD on the surface charge distribution are scarce. Thus, to overcome this research gap, this study measured the potential distributions of AC-driven surface DBD in oxygen (O2), synthetic air and nitrogen (N2) as background gases using the Pockels effect. The results showed that the patterns of the filamentary discharges generated during the positive voltage polarity phase differed depending on the O2 ratio. In addition, the electrostatic repulsion forces between the residual charge and the newly created filament were analysed from the measured potential distribution and the greatest effect was observed in air, rather than in N2 and O2. The potential distribution was transformed into a charge density distribution and compared with the discharge luminescence in air and N2. The results showed that the shape of the filament tip differed between the charge density and discharge luminescence only in the case of air, which was attributed to the effect of attachment reactions on the formation of residual charge. The measurements showed that in a surface discharge, similar to the case in a volume discharge, the photoionisation and ionisation coefficients significantly affected the geometrical properties of the discharges.

Understanding the role of ZnO nanosheet surface in photocatalytic dye degradation: The key to effective wastewater treatment

The current study proposes an introduction of interfering ions to the reaction medium as a simple way for obtaining efficient visible-light driven photocatalysts with active surface based on ZnO nanosheets. 9 samples with different morphological and structural parameters were obtained via simple and inexpensive precipitation and hydrothermal methods. XRD, SEM, FTIR, SSA, XPS, Raman, absorption spectra and DLS methods were used for ZnO nanosheet characterisation. An original approach was used to determine the amount of defects by processing Raman spectra via software specially designed for this purpose. XPS was used to estimate an overall amount of oxygen vacancies in the samples, and the DFT method was employed to model oxygen vacancies in the crystal structure. The latter were verified via absorption spectra. The most effective sample showed a dye degradation efficiency of 94 % after 60 min of irradiating by a common LED lamp available in a local store. The kinetic studies showed that the rate of adsorption and photodegradation depends on the DFT-calculated “surface-dye” interaction energy. Consequently, by regulating the ratio of ZnO nanosheet surface parameters, adsorption and photodegradation efficiency against a particular dye can be improved.

Studies of indium nanostructures growth models on A3B6 layered templates

This article explores the surface architecture formation on layered A3B6 semiconductors, such as In4Se3, InSe, and InTe, focusing on kinetics of surface roughness parameters, such as RMS, skewness and kurtosis, and power spectral density (PSD) under indium deposition studied through large-scale 1 × 1 µm2 and 150 × 150 nm2 scanning tunneling microscopy (STM) images analysis. Our findings reveal common kinetics of surface parameters across different crystals, suggesting fundamental similarities in their interface kinetics. Particularly, PSD analysis elucidates the role of low-frequency spatial structures, underscoring their significance in surface roughness kinetics to some extent independent of the specific layered crystal surface structure.

Finite Element Analysis of Plastic Deformation in Ultrasonic Vibration Superimposed Face Milling of Steel X46Cr13.

Ultrasonic vibration superimposed face milling enables the generation of predefined surface microstructures by an appropriate setting of the process parameters. The geometrical reproducibility of the surface characteristics depends strongly on the plastic material deformation. Thus, the precise prediction of the emerging surface microstructures using kinematic simulation models is limited, because they ignore the influence of material flow. Consequently, the effects of plastic as well as elastic deformation are investigated in depth by finite element analysis. Microstructured surfaces resulting from these numerical models are characterized quantitatively by areal surface parameters and compared to those from a kinematical simulation and a real machined surface. A high degree of conformity between the values of the simulated surfaces and the measured values is achieved, particularly with regard to material distribution. Deficits in predictability exist primarily due to deviations in plastic deformation. Future research can address this, either by implementing a temperature consideration or adapting specific modeling aspects like an adjusted depth of cut or experimental validated material parameters.

Construction and Validation of Surface Soil Moisture Inversion Model Based on Remote Sensing and Neural Network

Surface soil moisture (SSM) reflects the dry and wet states of soil. Microwave remote sensing technology can accurately obtain regional SSM in real time and effectively improve the level of agricultural drought monitoring, and it is of great significance for agricultural precision irrigation and smart agriculture construction. Based on Sentinel-1, Sentinel-2, and Landsat-8 images, the effect of vegetation was removed by the water cloud model (WCM), and SSM was retrieved and validated by a radial basis function (RBF) neural network model in bare soil and vegetated areas, respectively. The normalized difference vegetation index (NDVI) calculated by Landsat-8 (NDVI_Landsat-8) had a better effect on removing the influence the of vegetation layer than that of NDVI_Sentinel-2. The RBF network model, established in a bare area (R = 0.796; RMSE = 0.029 cm3/cm3), and the RBF neural network model, established in vegetated areas (R = 0.855; RMSE = 0.024 cm3/cm3), have better simulation effects on SSM than a linear SSM inversion model with single polarization. The introduction of surface parameters to the RBF neural network model can improve the accuracy of the model and realize the high-accuracy inversion of SSM in the study area.

Evaluation of adjuvant role of topical cyclosporine 1% in acute Stevens-Johnson syndrome: a randomised control trial

PurposeTo evaluate the role of topical cyclosporine A 1% (CsA) as an adjuvant therapy in patients with acute Stevens-Johnson syndrome (SJS).MethodsThis is a randomised controlled trial in which 44 patients...

Interactive design of discrete Voss nets and simulation of their rigid foldings

Voss nets are surface parametrizations whose parameter lines follow a conjugate network of geodesics. Their discrete counterparts, so called V-hedra, are flexible quadrilateral meshes with planar faces such that opposite angles at every vertex are equal; by replacing this equality condition with the closely related constraint that opposite angles are supplementary, we get so-called anti-V-hedra. In this paper, we study the problem of constructing and manipulating (anti-)V-hedra. First, we present a V-hedra generator that constructs a modifiable (anti-)V-hedron in a geometrically exact way, from a set of simple conditions already proposed by Sauer in 1970; our generator can compute and visualize the flexion of the (anti-)V-hedron in real time. Second, we present an algorithm for the design and interactive exploration of V-hedra using a handle-based deformation approach; this tool is capable of simulating the one-parametric isometric deformation of an imperfect V-hedron via a quad soup approach. Moreover, we evaluate the performance and accuracy of our tools by applying the V-hedra generator to constraints obtained by numerical optimization. In particular, we use example surfaces that originate from one-dimensional families of smooth Voss surfaces – each spanned by two isothermal conjugate nets – for which an explicit parametrization is given. This allows us to compare the isometric deformation of the smooth target surface with the rigid folding of the optimized (imperfect) V-hedron.

Does VS30 reflect seismic amplification? Observations from the West Bohemia Seismic Network

The present study addresses verification of average seismic shear-wave velocity from the surface to a depth of 30 m (VS30) as a suitable proxy for a seismic amplification. For this purpose, we used instrumentally homogeneous and spatially dense seismic network WEBNET (West Bohemia Seismic Network), designed to monitor an intraplate earthquake swarm activity in the West Bohemia/Vogtland region (Czech Republic/Germany). Using a Multichannel analysis of surface waves (MASW) shear-wave velocity models and parameters VS30 and H800 (depth of Vs > 800 m/s) were obtained at 17 WEBNET sites. VS30 were compared with (i) H800 and (ii) determined bedrock densities. To understand the relation between VS30 and site amplification, VS30 values were correlated with amplitudes of two earthquakes: (1) Mw 6.4 Petrinja, Croatia (12/2020) and (2) Mw 4.2 SE of Vienna, Austria (03/2021) both recorded by the WEBNET. The correlation analysis examined four categories of seismic waves in nine frequency windows and described the relation between amplification and VS30 using newly defined regression model. The results show that for the regression model, the frequency window with the highest correlation is in the 1–3 Hz range, and this dependence is statistically best observed in the full wave record. The amplification generally decreases with increasing VS30. However, a large scatter in amplification within Eurocode 8 category B is observed. Based on the observations a new general approach is put forward to finely indicate the relation between amplification and VS30 and the use of other site proxies is discussed.