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Protecting metal surfaces with organic coatings is one of the most common ways of corrosion protection. The main goal of coating is to insulate the base of the material from the corrosive environment in order to provide long lasting protection. The aim of this research is to show how different coating applications in combination with different drying methods affect the coating surface topography. Two different two-component primers were also observed, one containing zinc in its chemical composition and the other one not, to see if zinc had any effect on the surface topography. The surface topography of coatings is examined by the atomic force microscope. At the nano level, the surface condition is quantitatively described by areal topography parameters, also known as 3D roughness parameters. An accelerated laboratory test in the salt spray chamber was performed to compare topography parameters and evaluate which coating system had the slightest differences in observed parameters before and after exposure to a corrosive environment. All the results were statistically processed and presented.

The promotion of angiogenesis is a fundamental step for efficient organ/tissue reconstitution and replacement. Thus, several strategies to promote vascularization of scaffolds were studied to satisfy this unsolved clinical need. The interface between cells and substrates is a determinant for the success of tissue engineering (TE) strategies. Substrateâ s topography is reported to play a key role in influencing endothelial cell behavior, namely, on its proliferation, metabolic activity, morphology, migration, and secretion of cytokines and chemokines. Therefore, surface topography of the biomaterial-based grafts is a crucial property that is considered in the development of a new TE approach. Herein, we hypothesize that the surface of Rubus fruticosus leaf plays a crucial role in driving angiogenesis since its architecture resembles the vascular structures at a biologically relevant size scale. For this, we produced biomimetic polycaprolactone (PCL) membranes (BpMs) replicating the surface topography of a R. fruticosus leaf by replica molding and nanoimprint lithography. Our results showed an enhanced performance in terms of proliferation of the human endothelial cell line on top of the BpM. Moreover, an asymmetric cellular spatial distribution among the surface of the BpM was observed. These cells seem to have higher density for longer time periods in the region that replicates the leaf veins. Finally, we assess the angiogenic capacity through a chick chorioallantoic membrane assay, revealing that BpMs are more prone to support angiogenesis than flat PCL membranes. We strongly believe that this strategy can bring new insights into developing TE strategies with an enhanced performance in terms of the vascular integration between the host and the scaffolds implanted., This work is a result of the project FROnTHERA (NORTE-01-0145-FEDER-000023), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and Portuguese Foundation for Science and Technology under the doctoral programme in Tissue Engineering, Regenerative Medicine and Stem Cells (PD/59/2013 and PD/BD/128087/2016), and by the project Cells4_IDs (PTDC/BTM-SAL/28882/2017). The authors would like to acknowledge "BLUEBIOLAB.Laboratorio Transfronterizo de Biotecnologia Marina".0474_BLUEBIO-LAB_1_E financed by the European Regional Development Fund.

The surfaces of machined workpieces contain the signature of the manufacturing process. Indeed, the surface inaccuracies can be related to process parameters and machine vibrations. This paper aims at using process monitoring to identify the origin of surface topography defects. Thus, vibration and other process parameter measurements are correlated with profile measurements to establish the relationship between vibrations and surface topography for various process conditions. As each machine and process anomaly is reflected differently in the time and frequency domain, different analyses are applied both to temporal signals such as vibrations and to geometric signals obtained from the micro-geometry of the workpiece. Experimental results validate the diagnostic method and verify that the procedure is effective for the identification of topography defects originated not only from chatter vibrations but also from forced vibration coming from the kinematical chain (unbalance, beating...). The diagnostic method is successfully applied in various machining operations such as turning and grinding.

Tribological properties are determinant in the functionality of contacting surfaces of machine elements. The wear resistance or load bearing capacity influence the lifetime of these parts. In this study tribology-related surface topography parameters (Ssk, Sbi) and the hardness of hard turned surfaces are analyzed after hardness and topography measurements. Correlation coefficients were calculated for their relationships. It was found that the cutting parameters affect the wear resistance and the hardness in the opposite direction.

The most common long-term complication of silicone breast implants (SMI) remains capsular fibrosis. The etiology of this exaggerated implant encapsulation is multifactorial but primarily induced by the host response towards the foreign material silicone. Identified risk factors included specific implant topographies. Of note, breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), has only been observed in response to textured surface implants. We hypothesize that reduction of SMI surface roughness causes less host response hence better cosmetic outcome with fewer complications for the patient. A total of 7 patients received the routinely used CPX®4 breast expander (~60 µM Ra) and the novel SmoothSilk® (~ 4 µM Ra), fixed prepectoral with a titanised mesh pocket and randomized to the left or right breast after bilateral prophylactic NSME (nipple-sparing mastectomy). We aimed to compare the postoperative outcome regarding capsule thickness, seroma formation, rippling, implant dislocation as well as comfortability and practicability. Our analysis shows that surface roughness is an influential parameter in controlling fibrotic implant encapsulation. First time intra-individually compared in patients, our data confirm an improved biocompatibility with minor capsule formation around SmoothSilk® implants with an average shell roughness of 4 µM and in addition an amplification of host response by titanised implant pockets.

Micro milling is a common process for micro structuring component surfaces, e.g. for manufacturing material measures that are applied for the calibration of areal surface topography measuring instruments. In this study, the surface topography of material measures is investigated using various evaluation approaches (integral approach, correlation analysis, Fourier analysis). In doing so, confocal microscope and atomic force microscope measurements are used to compare cutting parameters for the appropriate micro milling process. For two milling tools it is shown that the surface topography depends primarily on the spindle speed and much less on the feed per tooth whereas differences between the milling tools are observed in the tendency to form substructures.

When surfaces with anisotropic texture are moved in different directions related to their assembled counterpart during operation, the friction conditions change, as they are determined by the lay of the topographies. In the article, contributing to the exploration of this characteristic, we analyze the inhomogeneity of the topography on a face milled plane surface with a symmetrical setting in sections at an angle of 30° or 60° to the feed direction. Roughness profiles are recorded at 13 points located equidistantly from each other in each measurement plane, and the degree and distribution of the roughness deviations are determined on the surface.

Surface topography plays an important role in mixed lubrication. However, the influence of the surface topography's morphological characteristics on lubrication performance is still not fully understood. In this article, we employ digital filtering and the Johnson transformation system, and we use a mixed plasto-elastohydrodynamic lubrication model to simulate the lubricated contact between rough spherical surfaces with different morphological characteristic parameters. The influence of skewness, kurtosis, and the wavelength factor, that is, the ratio between the autocorrelation lengths in the transversal and longitudinal directions, on contact pressure, film thickness, and von Mises (subsurface) stress, is examined with the mixed plasto-elastohydrodynamic lubrication model. The results confirm that plastic deformation leads to lower pressure distribution, distributed over a larger contact area than the pure elastohydrodynamic lubrication solution. Moreover, it is found that an increase in the kurtosis may improve the lubrication performance, while the opposite is true for the skewness and the wavelength factor. We believe that the insights obtained by means of the numerical simulations presented herein, would facilitate the design and manufacturing processes of the surfaces used for machine elements operating in the mixed plasto-elastohydrodynamic lubrication regime.

The surface topography of ceramic grinding wheels used in creep feed grinding is examined in this study. Creep feed grinding experiments are performed using seeded gel (SG) grinding wheels. The three-dimensional surface of the grinding wheel is observed using a two-dimensional high-definition laser displacement sensor, and the effective cutting-edge number is calculated based on three-dimensional surface observations. Microscopic wear behaviors of grain cutting edges are examined based on scanning electron microscope (SEM) images. The cutting-edge area percentage is calculated based on SEM images via the discriminant analysis method. Results show that the micro self-sharpening phenomenon can be evaluated quantitatively. Micro sharp cutting edges on grains and normal grinding forces are suppressed. Subsequently, the relationship between the grinding characteristics and behaviors of the SG wheel working surface is investigated.

The incidence of periprosthetic joint infections (PJIs) is ~2% of total procedures and it is expected to rise due to an ageing population. Despite the large burden PJI has on both the individual and society, the immune response to the most commonly isolated pathogens, i.e., Staphylococcus aureus and Staphylococcus epidermidis, remains incompletely understood. In this work, we integrate the analysis of synovial fluids from patients undergoing hip and knee replacement surgery with in-vitro experimental data obtained using a newly developed platform, mimicking the environment of periprosthetic implants. We found that the presence of an implant, even in patients undergoing aseptic revisions, is sufficient to induce an immune response, which is significantly different between septic and aseptic revisions. This difference is confirmed by the presence of pro- and anti-inflammatory cytokines in synovial fluids. Moreover, we discovered that the immune response is also dependent on the type of bacteria and the topography of the implant surface. While S. epidermidis seems to be able to hide better from the attack of the immune system when cultured on rough surfaces (indicative of uncemented prostheses), S. aureus reacts differently depending on the contact surface it is exposed to. The experiments we performed in-vitro also showed a higher biofilm formation on rough surfaces compared to flat ones for both species, suggesting that the topography of the implant could influence both biofilm formation and the consequent immune response.

AF1410 is a low carbon high alloy ultra-high strength steel. It not only has high strength and high toughness, but also has a high stress corrosion resistance. However, due to the characteristics of hard quality and poor thermal conductivity, AF1410 is a difficult material to process. In the process of milling, the geometric factors of process parameters, the flexible deformation of milling cutter and the flutter of the process system all affect the surface roughness, which makes it difficult to predict the surface roughness of milling parts. In order to solve this problem, a prediction model for surface topography of ultrahigh strength steel AF1410 was studied. To solve this problem, this paper studies the formation of milling surface topography, considers the dynamic displacement of the milling system, proposes a modeling method of surface topography based on the dynamic characteristics of the milling system and forms a prediction model. On this basis, the surface topography of ultra-high strength steel is simulated and analyzed, and the accuracy of the model is verified by experiments. The study realizes the prediction of milling surface topography of AF1410 parts and reveals the formation mechanism of milling surface topography from geometric and physical perspectives.

Electrical discharge machining is one of the most important non-conventional machining processes for removing material from electrically conductive materials by the use of controlled electric discharges. EDM is a non-contact machining process, therefore, is free from mechanical stresses. This paper investigates the machining Al7075-T6 alloy by EDM using a copper electrode. Al7075-T6 alloy was selected, because of its growing use in a lot of engineering applications. The effect of electrical parameters, peak current and pulse-on time, on the surface integrity, was studied. Area surface roughness parameters (arithmetical mean height, Sa, and maximum height, Sz) were measured on all samples and 3D surface characterization has been carried out with confocal laser scanning microscopy. The experimental results showed that the surface roughness is mainly affected by the pulse-on time., Електроерозійна обробка (ЕЕО) є одним з найбільш важливих нетрадиційних виробничих процесів і використовується для обробки з високою точністю електропровідних матеріалів, які важко обробляти звичайними процесами обробки. ЕЕО знаходить широке застосування в багатьох інженерних додатках, таких як обробка хірургічних компонентів, штампів та виготовлення прес-форм, а також в автомобільній і аерокосмічній промисловості. Останнім часом за допомогою електроерозійної обробки обробляються також м'які матеріали, такі як алюмінієві сплави, які широко використовуються в багатьох галузях промисловості, таких як морське, аерокосмічне, автомобільне та електричне обладнання. З усіх алюмінієвих сплавів серія 7xxx (яка також має назву алюмінієво-цинковий сплав) є найміцнішою серією алюмінієвих сплавів які підлягають деформації з кращими показниками на старіння і поліпшеними механічними властивостями. У цій статті досліджується обробка алюмінієвого сплаву Al7075-T6 за допомогою ЕЕО з використанням мідного електрода. Al7075-T6 - це високоміцний сплав, який використовується в якості конструкційного матеріалу в морських, автомобільних і авіаційних виробництвах, а також підходить для використання в ливарних формах. Було вивчено вплив пікового струму і тривалості імпульсу на шорсткість поверхні (SR). Характеристики поверхні також оцінювали за допомогою конфокальної лазерної сканувальної мікроскопії. Загалом, можна помітити, що піковий струм не має значного впливу на Sa. З іншого боку, збільшення часу включення призводить до збільшення Sa. Зокрема, Sa збільшився до 50,8% при збільшенні часу імпульсу від 100 до 500 мкс. Оброблена поверхня характеризується наявністю розподілу кратерів, які перекриваються, з нерівномірними слідами течії розплавленого металу і частинок відходів. Розмір утворених кратерів залежить від параметрів обробки і, отже, піковий струм і час імпульсу впливають на топографію поверхні.

The methodology of surface topography research plays a key role in identifying and describing the wear mechanism, including the tribological wear traces. In the published literature, wear traces are most often described based on the surface morphology created in the operation process (microscopic image – optical microscope OM, scanning electron microscope SEM, atomic force microscope AFM); less frequently used are 2D profile description (contact or non-contact profilometer) or 3D topography (profilometer, confocal microscope, interference microscope, focus variation microscope). Each method of testing the worn surface has its own characteristics and purposefulness of use. The combination of different methods enables a comprehensive assessment of the surface topography created in the operation process and the characterisation of tribological wear traces. This work presents the main issues in the range of research methodology of the surface topography created in the operation process (operated/worn surface topography) – the purpose of research, research programme, research methods and tools, analysis of research results (quantitative – parametric and qualitative – nonparametric). The research methodology of the surface topography and tribological wear traces is presented on selected examples. The method of conducting a comprehensive analysis, including all elements – surface morphology, 2D profile analysis and 3D topographic analysis – is discussed.

Materials science is about understanding the relationship between a material’s structure and its properties—in the sphere of mechanical behavior, this includes elastic modulus, yield strength, and other bulk properties. We show in this issue that, analogously, a material’s surface structure governs its surface properties—such as adhesion, friction, and surface stiffness. For bulk materials, microstructure is a critical component of structure; for surfaces, the structure is governed largely by surface topography. The articles in this issue cover the latest understanding of these structure–property connections for surfaces. This includes both the theoretical basis for how properties depend on topography, as well as the latest understanding of how surface topography emerges, how to measure and understand topography-dependent properties, and how to engineer surfaces to improve performance. The present article frames the importance of surface topography and its effect on properties; it also outlines some of the critical knowledge gaps that impede progress toward optimally performing surfaces.Graphical abstract

Introduction. The article is devoted to one of the problems in the development of oil and gas fields - the construction of correct geological models of the subsurface space. Researchers from various scientific groups around the world have proposed various ways to improve the accuracy of the computer simulations used in this process. The purpose of this study is to assess the degree of influence of the day surface relief and the anisotropy of the upper part of the geological section on the recorded seismic signal using a realistic model of the Orenburg field as an example.Materials and methods. A seismogeological model describing the Lower Permian interval of the Orenburg geological section is considered. According to well data, the elastic properties of geological formations were estimated: density and propagation velocities of longitudinal and transverse waves. There is a high contrast of P-wave velocities estimated from sonic logs. The reservoir in this model is confined to the lower layers. It is composed of sulfate-carbonate media, uniform in density and acoustic properties. Using the grid-characteristic method, zero-offset synthetic seismograms were calculated. The choice of structural curvilinear computational grids made it possible to correctly consider the relief of the day surface.Research results. In this work, two different models were compared. The first model included the anisotropy of the upper part of the section and the topography of the day surface. In the second model, the upper boundary of the computational domain was flat, and the entire medium was considered within the framework of an isotropic linear elastic model. The analysis of synthetic seismograms showed that the anisotropy inherent in this model does not significantly affect the recorded seismic wave field. However, considering the relief of the day surface significantly shifts the times of arrival of reflected waves.Discussion and Conclusion. The algorithm presented in the paper can be used to verify the field data processing graph, since the assessment of the anisotropy of the medium is a standard step in building a velocity model. The presented approach can be extended to 3D models of realistic dimensions.

The near-surface anisotropy is one of the factors leading to an inaccurate velocity estimation in the shallow area, which has a strong impact on the static correction of land data and seismic imaging of the subsurface in depth. To investigate the anisotropy influence, the consideration of medium anisotropy in near-surface seismic modeling becomes necessary. In the oil and gas industry, finite-difference (FD) methods are commonly used for seismic wave modeling, thanks to their simplicity, accuracy, and high efficiency. However, for near-surface modeling, the implementation of free-surface boundary conditions and nonflat topography representation are the two main obstacles preventing the effectiveness of FD methods. To address these two issues in the vertical transversely isotropic anisotropic scenarios, we have developed a simple and efficient method for the discrete model design which can be easily applied to the conventional Cartesian-grid FD modeling. Our method involves: (1) the parameter-averaging method for implicitly implementing the stress-free condition by a modification of model anisotropy parameters near the (non) flat free-surface boundary and (2) an independent wavefield superposition with modeling results of different parameter configurations to accurately represent the rugged topography and significantly reduce the staircase diffractions caused by a staircase approximation of continuous surface in the Cartesian-grid discretization. For validation of this method, we conduct several numerical tests in 2D and 3D spaces. The accuracy is demonstrated by a comparison of the spectral-element solutions of SPECFEM in modeling the seismic wave propagation in the presence of an irregular free surface. From the aspect of computational efficiency, it is more promising in practical applications due to the use of wavefield superposition strategy in this method which does not require finer spatial sampling to eliminate the staircase diffractions.

The critical role and mechanism of the topography of materials to regulate the function and fate of mesenchymal stem cells are reported.

Revealing forming mechanism of workpiece surface topography plays an important role in improving ultraprecision turning. In this paper, the forming mechanism of the turning workpiece surface topography is analyzed and verified by the theoretical simulation and experiment respectively. First, the factors directly related to the turning process are analyzed, and a volumetric error model is built and discussed, which considered geometric errors, tool geometry, spindle vibrations, feed rate, cut depth, and feed system position change. The vibration mechanism and laws of the spindle system under multi-field coupling is analyzed, and the effect of the spindle axial vibration on the turning surface topography is studied. In addition, influence of coupled vibrations on the turning surface texture is analyzed, and an equivalent machining model is constructed to identify crucial geometric errors of the workpiece surface topography. Finally, a homemade ultraprecision machine tool system is built and used for turning the workpiece surface, and the tested results of the surface topography demonstrate Ra is better, 10 nm and Rv is better, 20 nm. The end face of the workpiece forms periodically fluctuating wave and ripple patterns, and the comparison between theoretical analysis and experimental detection of the surface topography is verified.

Particle removal from the surface of a substrate has been an issue in numerous fields for a long time. In semiconductor processes, for instance, the formation of clean surfaces by removing photoresist (PR) must be followed in order to create neat patterns. Although PR removal has been intensively investigated recently, little is known about how ultraviolet (UV) and developer solutions alter the PR resin (and in what manner) near the surface. While varying the exposure times of UV and developer solution, we investigated the topographic changes on the surfaces of PR resin films and particles. The measured surface properties were then correlated with the detachment force determined using films, and eventually with the residual PR particle removal percentages obtained in a microchannel. Using a positive PR and a base developer solution, we demonstrated that UV causes the surface of PR resin to become hydrophilic and wavy, whereas the developer solution produces a surface with a larger degree of roughness by swelling and partially dissolving the resin. Ultimately, the increased roughness decreased the effective contact area between PR resins, hence decreasing the detachment force and increasing the particle removal percentages. We anticipate that our findings will help understand residual particle issues, particularly on the removal mechanism of PR resins based on surface topography.

The opening up of the global positioning system (GPS) for non-military uses provided a new impetus for the study of the sea surface topography (SST) and geoid, especially in coastal areas which are important from the viewpoint of the climate crisis. The application of the “GPS/GNSS on boat” method, as an alternative to traditional (indirect and direct) methods, has provided detailed SST maps in coastal and oceanic areas with an accuracy of up to few centimeters. In this work we present the first critical review concerning the evolution of the “GPS/GNSS on boat” method over a period of 27 years. Twenty-one papers, covering the 27 years of related research, are critically reviewed, focusing on the innovations they introduce, the solutions they present and the accuracy they achieve. Further improvement of the method, principally of its accuracy, and the extension of SST measurements to additional coastal environments open new perspectives for the examination of open geophysical problems and climate change.

In this review, the authors provide a general review of current research themes where complex surface topography plays a role. Recent innovations and research possibilities have opened up using modern microtopography creation techniques. This review considers a large range of themes in limited depth to provide an introduction and to illustrate how broad the field is and, to those already working in the area, to help gain a broad perspective. Due to the breadth of scope, this review does not go into much depth into any given area. This review aims to provide a comprehensive understanding of and practical guidance on the modern use of micro- and nanotopography to control water; adhesion; wettability; biological adhesion, including implants, cell culture and biofouling; and directional fluid transport. The broad range of functionality is highlighted in the many interfacial interactions. However, the methods allowing economy of scale allowing these surfaces to be used commonly is still in development. To make this review more accessible, the authors have chosen to concentrate on open-access articles to cite.

The paper presents probabilistic aspects of diagnostics of grinding processes with consideration of metrological aspects of evaluation of topography of machined surfaces and selected problems of assessment of machining accuracy. The processes of creating the geometric structure of the ground surface are described. It was pointed out that the distribution of features important for process diagnostics depends on the mechanism of cumulative effects of random disturbances. Usually, there is a multiplicative mechanism or an additive mechanism of the component vectors of relative displacements of the tool and workpiece. The paper describes a method for determining the classification ability of specific parameters used to evaluate stereometric features of ground surfaces. It is shown that the ability to differentiate the geometric structure of a certain set of surfaces using a selected parameter depends on the geometric mean of the differences in normalized and sorted, consecutive values of this parameter. A methodology is presented for evaluating the ability of various parameters to distinguish different geometric structures of surfaces. Further, on the basis of analyses of a number of grinding processes, a methodology was formulated for proceeding leading to a comprehensive evaluation of machining accuracy and forecasting its results. It was taken into account that in forecasting the accuracy of grinding, it is necessary to determine the deviations, arising under the conditions of multiplicative interaction of the effects of various causes of inaccuracy. Examples are given of processes in which, due to the deformation of the technological system, dependent on the position of the zone and machining force, varying temperature fields and tool wear, the distributions of dimensional deviations are not the realization of stationary processes. It was emphasized that on the basis of the characteristics of the dispersion of the deviation value in the sum set of elements, it is not possible to infer its causes. Only the determination of the “instantaneous” values of the deviation dispersion parameters allows a more complete diagnosis of the process.

Abstract This study was performed to characterize surface topography and microhardness of 40 wt pct NiCrBSiC-60 wt pct WC hard coating on TC4 titanium after coaxial laser cladding via Laser Induced Breakdown Spectroscopy (LIBS) and machine learning. The high content of the hard WC particles is accomplished to enhance the abrasion wear resistance of such alloy. Various powder feeding rates were carried out during laser cladding process. The energy-dispersive X-ray analysis assured that W content in the metal matrix notably increased from 26.19 to 53.49 pct while the Ti content decreased from about 15.16 to 0.46 pct for the clad layer processed at 20 and 60 g min−1, respectively. The LIBS measurements successfully estimated such elements’ concentration as well as the clad layers' topography indicating that the effect of material matrix is a crucial challenge. Therefore, canonical correlation analysis and Belsley collinearity diagnostics were established to identify the essential emission lines from the whole spectra. Then, an optimized adaptive boosted random forest classifier was developed for microhardness investigation, with accuracy, sensitivity, and F1 score values of 0.9667. The results, confirmed by the metallurgical study, clarified that most of the titanium and tungsten emission lines have a significant impact on the surface topography as well as the microhardness values. The misclassification was attributed to the matrix effect such that the samples processed at 40 and 60 g min−1 were comparable in microstructure and chemical characterization unlike the one processed at 20 g min−1. Vickers microhardness of the metal matrix coating increased with the increase in the powder feeding rate, which is assured by the quantitative classification model. Graphical Abstract

In conventional grinding (CG), camshafts with wide profiles suffer from poor quality and low efficiency because the large contact area between the grinding wheel and camshaft profile limits the diffusion of grinding temperature, leading to burn defects. Swing grinding (SG) can mitigate these problems as it involves a reciprocating motion along the axis of the grinding wheel; however, the lack of understanding of machined surface topography has restricted its application. Therefore, in this study, a surface topography prediction model was proposed based on the distribution, shape, and trajectory of grains. The model was verified through experiments, and the mean error was 10.2% for Rax and 3.8% for Ray ; the roughness along the grinding direction was Rax , and the roughness along the vertical grinding direction was Ray . Compared to CG, SG has a 8% lower Rax . The influence of the wheel speed and feed rate in SG is consistent with that in CG. Rax exhibited a periodic trend with an increase in the swing amplitude and a monotonically decreasing trend with an increase in the swing frequency. The variation trend of Ray with the swing amplitude was the same as that of Rax . Furthermore, Ray exhibited a nonlinear increasing trend with an increase in swing frequency. Considering the processing and practical application of camshafts, the swing amplitude should be within 4 mm, the swing frequency should be within 3 Hz, the grinding wheel speed should be large, and the feed rate should be small.

Purpose To estimate the criterion validity of sagittal thoracolumbar spine measurement using a surface topography method in a clinical population against the gold standard and to estimate concurrent validity against two non-radiographic clinical tools. Methods In this cross-sectional validity study, thoracolumbar curvature was measured in adults with spinal conditions recruited from a specialist orthopaedic hospital. A surface topography method using a Kinect sensor was compared to three other measurement methods: spinal radiograph (gold standard), flexicurve and digital inclinometer. Correlation coefficients and agreement between the measurement tools were analysed. Results Twenty-nine participants (79% female) were included in criterion validity analyses and 38 (76% female) in concurrent validity analyses. The surface topography method was moderately correlated with the radiograph (r = .70, p r = .32, p = .89). The surface topography method was highly correlated with the flexicurve (rs = .91, p r = .82, p r = .74, p r = .74, p Conclusions The surface topography method showed moderate correlation and agreement in thoracic spine with the radiograph (criterion validity) and high correlation with the flexicurve and digital inclinometer (concurrent validity). Compared with other non-radiographic tools, this surface topography method displayed similar criterion validity for kyphosis curvature measurement.

In this paper, the validity of the application of an autocorrelation function for resolving some surface topography measurement problems was presented. Various types of surfaces were considered: plateau-honed, honed with burnished dimples, ground, turned, milled, laser-textured, or isotropic. They were measured with stylus and non-contact (optical) methods. Extraction of selected features, such as form and waviness (defined as an L-surface) and high-frequency measurement noise (S-surface) from raw measured data, was supported with an autocorrelation function. It was proposed to select the analysis procedures with an application of the autocorrelation function for both profile (2D) and areal (3D) analysis. Moreover, applications of various types of regular (available in the commercial software) analysis methods, such as least-square-fitted polynomial planes, selected Gaussian (regression and robust) functions, median filter, spline approach, and fast Fourier transform scheme, were proposed for the evaluation of surface topography parameters from ISO 25178 standards.

A surface topography characterization parameter system based on fractal parameters has been established, and several estimation methods for these fractal parameters have been suggested accordingly. Since scale dependence exists in these conventional methods, it is necessary to find an estimation method for characterization parameters with uniqueness. An estimation method for ideal fractal parameters for multi-scale measurement of polished surface topography is proposed in this study. Polished surfaces of two materials, WC-Ni and 9Cr18Mo, are measured under multi-scale for frequency component analysis. This study proposes an estimation method for ideal fractal parameters based on a modified determination method for the scale-free region and the decomposition of frequency components into three classifications. The reasonable results verify the existence of ideal fractal parameters: for the WC-Ni surface, ideal fractal dimension D = 1.3 and scale coefficient G = 2.23×1020μm; for the 9Cr18Mo surface, ideal fractal dimension D = 1.2 and scale coefficient G = 3.33×1033μm. Additionally, it is revealed that the scale-dependent components conform to the same regulation on the same instrument by comparing the results of two materials. The conclusions of this study are expected to support tribology research and mechanical engineering related to surface topography.

Improving the performance of nanocarriers remains a major challenge in the clinical translation of nanomedicine. Efforts to optimize nanoparticle formulations typically rely on tuning the surface density and thickness of stealthy polymer coatings such as poly(ethylene glycol) (PEG). Here, we show that modulating the surface topography of PEGylated nanoparticles using bottlebrush block copolymer (BBCP) significantly enhances circulation and tumor accumulation providing an alternative strategy to improve nanoparticle coatings. Specifically, nanoparticles with rough surface topography achieve high tumor cell uptake in vivo due to superior tumor extravasation and distribution compared to conventional smooth-surfaced nanoparticles. Furthermore, surface topography profoundly impacts the interaction with serum proteins resulting in the adsorption of fundamentally different proteins onto the surface of rough-surfaced nanoparticles formed from BBCPs. We envision that controlling the nanoparticle surface topography of PEGylated nanoparticles will enable the design of improved nanocarriers in various biomedical applications.

The combination of the pellet additive manufacturing (PAM) process and green ceramic machining within the same hybrid machine is a very promising route to obtain green ceramic parts with complex shapes, smooth surface topography and tight tolerances. However, there is still a lack of data due to the novelty of this manufacturing route. This article studies the possible influence of the build and in-plane directions on the cutting forces and surface topography during the milling of Y-TZP green ceramic parts obtained by the PAM process. The RMS cutting forces, arithmetic and total roughness (Ra and Rt, respectively) were measured. The in-plane direction (aligned with one of the horizontal part edges) did not have a significant influence neither on the cutting forces nor on the surface topography. Conversely, the build direction has a significant effect on the cutting forces recorded. The layers deposited the furthest from the build platform required 57.5% less force to be milled than those in contact with it. The surface topography was not significantly modified across the build direction, all values of Ra were within the 0.8 µm Ra class while all Rt values were < 5 µm.

Laser engraving process is widely used for various industrial applications, such as the creation of small and complex geometries with ultra-high precision. As surface topography can affect the functionality of produced surfaces in various ways, it is required to carry out comprehensive experimental work in order to correlate the laser engraving process parameters with surface topography characteristics. In the current paper, the surface topography of SAE304 stainless steel specimens in respect to laser power, scanning speed and pulse repetition rate is studied through microscope observations. The findings indicate that the scanning speed is the most dominant parameter regarding surface roughness and from the viewpoint of surface quality, it is suggested that higher scanning speed, lower power and pulse repetition rate values should be employed.