Surface Techniques Research Articles

Dorsal Preservation Rhinoplasty-the Perspective of "Preservers" Versus "Structural" Surgeons.

The objective of this study was to describe the surgeons who have incorporated dorsal preservation (DP) into their practice and their techniques. An anonymous form reviewed by the Evidence-Based Rhinoplasty Research Group board was shared on its Telegram group. The study population was divided into three groups based on their answers: "Preservers," "Mainly Structural," and "Structural exclusively." This study included the answers of 145 worldwide surgeons. DP was more common among plastic surgeons than otolaryngologists/facial plastic surgeons; DP techniques were mostly preferred by surgeons with 10-20 years of experience, while structural techniques were mostly preferred by surgeons with > 20 years of experience; 50.8% of the surgeons who prefer DP techniques use it in more than 90% of primaries; surface techniques (ST) have been more used, mainly by surgeons who prefer structural techniques (p < 0.001). ST were considered more stable (p < 0.001), more predictable (p < 0.001), and shorter learning curve (p < 0.001). Many surgeons using DP still perform structural rhinoplasty. The most cited concern was hump persistence/recurrence. DP rhinoplasty is gaining acceptance, and ST are favored for their perceived short learning curve, stability, and predictability. However, concerns about hump recurrence cause some to continue using structural methods alongside DP.

A novel use of non-contact methods in analyzing the physical and technical surface characteristics of different materials using electromagnetic measurement techniques

Researchers and industry professionals often use surface metrology techniques to analyze and quantify these surface characteristics, enabling them to make informed decisions about machining strategies and process improvements. This paper presents a comprehensive exploration of surface characteristics of two different materials i.e., C45 steel and brass using electromagnetic measurement techniques. The research used techniques based on: Coherence Scanning Interferometry, Confocal, Focus Variation and Confocal Fusion. Additionally, different light colours were used for these techniques and measurement methods to assess their impact on the quality of mapping the electromagnetic surface. The results demonstrate that the regardless of the colour of the scanned surface (steel or brass), only approximately 50 % of the profile points achieved a 40 % match with the base profile points by scanning with blue light.

Sub-THz Characterization of Technical Surfaces for Particle Accelerator Vacuum Chambers.

Coatings play a crucial role in the functionality of vacuum chambers in particle accelerators, serving a dual goal by efficiently facilitating pumping and mitigating electron cloud effects. However, their impact on the surface impedance of the chamber walls raises concerns, potentially affecting the machine performance and imposing limitations on achievable energies and currents. Therefore, an electromagnetic characterization is essential for a comprehensive study of accelerator structures, particularly in the context of the next-generation machines where the demand for extremely short particle bunches accentuates the importance of evaluating material responses in the very-high-frequency region. We present a technique for probing the sub-THz response of coating materials by measuring pulsed signals passing through a specifically designed waveguide, in which is placed a slab with the deposited material under test. The proposed methodology allows for a comprehensive exploration of the electromagnetic properties of the most used technical surfaces (substrate plus coatings) in accelerators under realistic conditions, providing valuable insights into their behavior in the sub-THz frequency range. The experimental data of three different Non-Evaporable Getter coating samples, prepared on a copper substrate at the CERN deposition facilities under different sputtering conditions, are discussed. The findings contribute to a deeper understanding of the complex interactions between coatings and accelerator structures, with the aim of optimizing performance and efficiency in the evolving landscape of particle acceleration technologies. The limitations and advantages of the technique are also reported.

On the Validity of the Flow Factor Concept with Respect to Shear-thinning Fluids

This contribution aims to determine the error introduced by assuming constant viscosities in the calculation of the flow factors for non-Newtonian fluids. For this purpose, a simulation model based on the generalized Reynolds equation according to Dowson is used to evaluate shear thinning effects for various oils as well as different technical surfaces.

High-resolution coherence scanning immersion interferometry for characterization of technical surface topographies

Zusammenfassung Die Kohärenz-Scanning- Interferometrie ist eine berührungslose optische Messmethode zur hochauflösenden dreidimensionalen Charakterisierung von Oberflächentopographien. Um die laterale Auflösung eines Interferenzmikroskops zu verbessern, wurde erstmals ein Linnik-Interferometer mit hochaperturigen Immersionsobjektiven aufgebaut und zur Messung technischer Oberflächen eingesetzt. Diese Studie zeigt den Einfluss eines Immersionsmediums zur Verbesserung der lateralen Auflösung und vergleicht Immersions- und Nicht-Immersionssysteme in Bezug auf Signalbildung und Übertragungsverhalten im dreidimensionalen Ortsfrequenzraum. Die Messergebnisse von transparenten AMONIL®-Gittern zeigen eine signifikante Verbesserung der Signalqualität im Vergleich zum Nicht- Immersionssystem. Außerdem werden Messergebnisse von Halbkugeln vorgestellt, die durch Substrate Sonformal Imprint Lithography substrukturiert wurden.

Rapid Detection of Cleanliness on Direct Bonded Copper Substrate by Using UV Hyperspectral Imaging.

In the manufacturing process of electrical devices, ensuring the cleanliness of technical surfaces, such as direct bonded copper substrates, is crucial. An in-line monitoring system for quality checking must provide sufficiently resolved lateral data in a short time. UV hyperspectral imaging is a promising in-line method for rapid, contactless, and large-scale detection of contamination; thus, UV hyperspectral imaging (225-400 nm) was utilized to characterize the cleanliness of direct bonded copper in a non-destructive way. In total, 11 levels of cleanliness were prepared, and a total of 44 samples were measured to develop multivariate models for characterizing and predicting the cleanliness levels. The setup included a pushbroom imager, a deuterium lamp, and a conveyor belt for laterally resolved measurements of copper surfaces. A principal component analysis (PCA) model effectively differentiated among the sample types based on the first two principal components with approximately 100.0% explained variance. A partial least squares regression (PLS-R) model to determine the optimal sonication time showed reliable performance, with R2cv = 0.928 and RMSECV = 0.849. This model was able to predict the cleanliness of each pixel in a testing sample set, exemplifying a step in the manufacturing process of direct bonded copper substrates. Combined with multivariate data modeling, the in-line UV prototype system demonstrates a significant potential for further advancement towards its application in real-world, large-scale processes.

Preservation Rhinoplasty by the Ones Who Do It: A Worldwide Survey.

Dorsal preservation (DP) rhinoplasty techniques, including surface techniques (STs) and foundation techniques (FTs) have garnered significant attention internationally over the past few years. The practice patterns and opinions from 117 of these surgeons were surveyed from a cohort of these surgeons who participate in an online Evidence-Based Rhinoplasty Research Group. The findings of the survey are merely a snapshot of the international rhinoplasty community's practices, yet did capture data from surgeons from a diverse geographic, years of experience, and training background. STs were most used for the bone changes, and the high-strip technique was preferred for the cartilaginous septal surgery. STs are mostly performed by younger surgeons (<10 years of experience), whereas FTs were more common in older surgeons (10-30 years of experience). STs were considered more stable (p < 0.001), more predictable (p < 0.001), and associate with a shorter learning curve (p = 0.015). Revision surgery rates were not different. Regarding why many surgeons using DP still perform structural rhinoplasty, the most cited concern was hump persistence/recurrence. In summary, among surgeons using DP rhinoplasty techniques, the majority perform DP in over half of their primary rhinoplasty surgeries, highlighting the importance of updating educational programs in medical training, conferences, and courses.

Effect of HVOF spray coating on the tribological surface of onshore gate valves

Gate valve is one of the most common design concepts in onshore Oil & Gas installations. This equipment is composed of a wedge-shaped obturator that performs linear sliding movements during activation. Fluid sealing is achieved through metallic contact between the surfaces of the gate and seat components. Metal surfaces are commonly hardened by heat treatment or coated with Stellite 6 alloy by plasma-transferred arc welding (PTAW). The application of high-velocity oxygen fuel (HVOF) coatings on these surfaces for wedge-gate valves has not yet been foreseen. In addition, comparative studies on the tribological performance of technical surfaces used in onshore wedge-gate valves are also scarce. Therefore, this study presents the results of tests performed on specimens using a ball-on-flat tribometer with linear reciprocating sliding, simulating a gate valve tribosystem in operation: flat (gate) and ball (seat). Martensitic stainless steel 13Cr was used with the contact interfaces under the following conditions: (A) heat treated, (B) Stellite 6 coating by PTAW, (C) Stellite 6 coating by HVOF, and (D) tungsten carbide coating by HVOF. The flat/ball tribological pairs investigated were A/B (TRIM 8), B/B (TRIM 5), C/B, and D/B. The coefficient of friction (COF), surface wear, and wear mechanisms were comparatively evaluated. The results showed that the newly proposed surfaces (C and D) are promising alternatives to reduce material consumption and improve the performance of valves in operation according to the application requirements.

High‐Speed Laser Surface Structuring for Thermal Spray Coating Preparation

The preparation of surfaces for coating processes is indispensable for maximal adhesion and good coating results. These technical surfaces can be treated by chemical, mechanical, or physical procedures. In thermal spray coating, grit blasting is a standard process for surface preparation. This mechanical roughening and activation of the surfaces is fast and easy to handle. On the negative side, the grit gets wasted and the generated pattern is inflexible. Therefore, attempts to substitute grit blasting with a laser application is discussed in this article. Herein, a theoretical evaluation of high‐speed laser surface texturing (LST) is performed to find limits and points for the optimization of these processes. To estimate the surface processing rates, continuous wave, nanosecond, and ultrashort pulse laser machined dimples and grooves are investigated, and results of the spray coatings are presented afterward. The steel substrates are coated with Stellite 6 and tungsten. Adhesion tests and coating structures are analyzed. In terms of the optimization of the laser texturing, in situ temperature measurements show the influence of the laser process speed on the thermal load of the substrate. The influence of the number of scanning repetitions on heat accumulation during LST is also analyzed.

Research on the impact of China's reform to delegate power, streamline administration, and optimize government services on the technology innovation efficiency of the pharmaceutical manufacturing industry.

The government has recently implemented reforms aimed at delegating power, streamlining administration, and optimizing government services. This reform has eliminated barriers that impede the growth of various industries, thereby unleashing innovative potential. Additionally, there have been several medical policies, including changes to medical insurance and centralized volume-based procurement. China's pharmaceutical market has undergone significant changes, leading to increased demands for innovation technology efficiency in pharmaceutical manufacturing. The three-stage BCC theory was employed to assess the effectiveness of technology innovation in the industry under this reform. Calculate precise comprehensive technical efficiency values, pure technical efficiency values, and scale efficiency values for technological innovation in the pharmaceutical industry across 30 provinces from 2018 to 2020, after removing environmental factors. In 2020, Jiangsu and Shandong and nine other provinces reached the comprehensive technical efficiency frontier surface, joining Tianjin, Zhejiang, and Guangdong provinces. However, Gansu, Qinghai, Ningxia, and Xinjiang still need to catch up due to their smaller industrial scale and lack of technology. To ensure the effectiveness of reforms, it is crucial to fully consider provincial differences. Articulating national and provincial policies is necessary to allow efficient provinces to continue and allocate resources toward less efficient provinces to improve overall efficiency.

Influence of Laser Process Factors on Laser‐Induced X‐Ray Emission in High‐Repetition Laser Processes

Lasers have established themselves as a versatile tool that generates innovations in a wide range of fields, from automotive to surface engineering, medical applications, etc. A current research field for lasers is surface texturing in biomimetic, which aims to mimic nature‐inspired functionalities and mechanisms, for example, to tailor and control wetting, adhesion/friction, or optical properties of technical surfaces. Therefore, ultrashort pulse lasers are often the right choice to alter surface structures at microscopic scale. Moreover, the ongoing trend toward high‐average power lasers reaching “kilowatt class” levels even for ultrashort pulse lasers seems to be beneficial to increase throughput of this powerful laser technology for industrial production. However, several recent studies are reported on harmful X‐ray emissions arising from high‐intense ultrashort laser pulses which must be considered as a secondary laser beam hazard in risk assessment. Shining light on this topic, this article reports on a set of experiments investigating X‐rays emission induced by ultrashort pulse laser processing of different laser‐pretreated stainless steel sheets. The X‐ray measurements show the effect of roughness and scan number on the laser‐induced X‐ray emission dose. In addition, the dependency of X‐ray emission on the scan direction relatively to the laser beam polarization state is discussed.

Micro- and Nano-Roughness Separation Based on Fractal Analysis.

When describing the tribological behaviour of technical surfaces, the need for full-length scale microtopographic characterization often arises. The self-affine of surfaces and the characterisation of self-affine using a fractal dimension and its implantation into tribological models are commonly used. The goal of our present work was to determine the frequency range of fractal behaviour of surfaces by analysing the microtopographic measurements of an anodised aluminium brake plunger. We also wanted to know if bifractal and multifractal behaviour can be detected in real machine parts. As a result, we developed a new methodology for determining the fractal range boundaries to separate the nano- and micro-roughness. To reach our goals, we used an atomic force microscope (AFM) and a stylus instrument to obtain measurements in a wide frequency range (19 nm-3 mm). Power spectral density (PSD)-based fractal evaluation found that the examined surface could not be characterised by a single fractal dimension. A new method capable of separating nano- and micro-roughness has been developed for investigating multifractal behaviour. The presented procedure separates nano- and micro-roughness based on the geometric characteristics of surfaces. In this way, it becomes possible to specifically examine the relationship between the micro-geometry that can be measured in each wavelength range and the effects of cutting technology and the material structure that creates them.

Smoothness assurance of the restorable surface of the cones of drill bits by cubic splines

The article covers the issues of the application of the spline functions in engineering practice, in particular, in the design of cone drill bits. The polynomial splines, which most commonly used in computational methods are also described. It is also expedient to indicate three important advantages of the spline function for describing the design of cone drill bits. Obtaining a unified mathematical equation for the technical surface of the cones of drill bits is a routine work. The construction of a cubic spline causes difficulties due to the determination of the parameters of the spline, which requires the solution of a system of linear algebraic equations. At the same time, the constructed splines provide second-order smoothness in any direction of the surface line. Further splines of the fifth degree which is reduced to solving a complex system of equations have been developed.

Selective lethal impact of blue laser radiation compared to high-power LED irradiation on naturally grown biofouling in the context of underwater biofouling cleaning

Technological advances in blue laser sources are expanding the possibilities for using high-power laser radiation, particularly in the range of 1 kW and above, in marine environments, due to the reduced absorption of laser radiation below 550 nm in water. These developments are creating new opportunities for high power laser underwater applications. One key application is the removal of biofouling from submerged technical surfaces like ship hulls by causing lethal damage to attached organisms. This research investigated the effect of radiation power density on lethal damage to organisms, focusing on naturally grown biofouling. Experiments were carried out with different power densities in the range from high-power blue light emitting diodes (LED) at 0.02 W/mm² to high-power blue lasers at 3.88 W/mm². These results help to understand the relationship between radiation parameters and biological responses, which is crucial for optimizing environmentally friendly technologies.

CATHODIC PLASMA ELECTROLYTIC DEPOSITION (CPED) TECHNIQUE FOR SURFACE STRENGTHENING OF TITANIUM AND TITANIUM ALLOYS: A MINI REVIEW

Due to the unique properties of titanium (Ti) and its alloys, it has a particularly wide range of applications in aerospace, automotive, medical and other fields. However, the problems of low surface hardness, high friction coefficient and low wear resistance of Ti alloys limit its development to a certain extent. The destruction of Ti and its alloys often occurs on the surface of materials such as wear damage, corrosion, and oxidation resistance. Therefore, the exploration and application of surface strengthening technology is particularly important. The cathodic plasma electrolytic deposition (CPED) technology, as a surface modification technology, can achieve better adhesion and facilitate the material to achieve better comprehensive performance. This paper briefly introduces the basic concepts, principles and development progress of CPED. Starting from the preparation of ceramic coatings, metal coatings, diamond-like carbon films and composite coatings, it summarizes the application of CPED in Ti and its alloys. Applications in alloys to improve thermal oxidation resistance, wear resistance, corrosion resistance, and film-based adhesion. At the end, its development in the new era environment is prospected.

Technique of Real-Time Detection of Technical Surface Defects

Technique of Real-Time Detection of Technical Surface Defects

Machine learning guided development of high-performance nano-structured nickel electrodes for alkaline water electrolysis

Utilizing a human in the loop Bayesian optimisation paradigm based on Gaussian process regression, we optimized an Ni electrodeposition method to synthesize nano-structured, high-performance hydrogen evolution reaction electrodes. Via exploration-exploitation stages, the synthesis process variables current density, temperature, ligand concentration and deposition time were optimized influencing the deposition layer morphology and, consequently, hydrogen evolution reaction activity. The resulting structures range from micrometre-sized, star-shaped features to nano-sized sandpaper-like structures with very high specific surface areas and good hydrogen evolution reaction activity. Using the overpotential at 10 mA cm−2 as the figure of merit, hydrogen evolution reaction overpotentials as low as -117 mV were reached, approaching the best known technical high surface area electrodes (e.g. Raney Ni). This is achieved with considerably fewer experiments than what would have been necessary with a linear grid search, as the machine learning model could capture the unintuitive interdependencies of the synthesis variables.

Laser‐Textured Surfaces: A Way to Control Biofilm Formation?

AbstractBacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria‐repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria‐repellent surfaces lies in the contactless and aseptic large‐area laser‐processing of technical surfaces. Tailored surface textures, enabled by different laser‐processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state‐of‐the‐art review of laser‐surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser‐processed surfaces, the challenges of anti‐microbial surface designs are discussed, and future directions will be outlined.

A novel method for measurements of surface topography in previously inaccessible areas

Abstract Since mechanical properties of parts in mechanical engineering are influenced in many ways by their surface structure, detailed knowledge of the surface structure is essential for predicting and describing these properties. Tactile and optical measurement methods are well established but cannot always reach every area of a part due to geometric constraints. To enable measurements in these areas, a method utilizing impressions and a laser scanning microscope is proposed. It is easy to use and able to correctly reproduce surface structures of technical surfaces, which is proven by a comparison of original parts and impressions of three surface areas on an example specimen. Two application examples from the domain of fatigue strength tests are shown. The surface structure is measured directly in the notch radius of shaft shoulders and inside hollow shafts made in different manufacturing processes. Utilizing modern optical measurement instruments, the proposed method enables accurate measurements of surface structure in previously inaccessible areas.

Investigation of Oxide Thickness on Technical Aluminium Alloys—A Comparison of Characterization Methods

In this study the oxide layer of technical 6xxx aluminium surfaces, pickled as well as passivated, were comparatively investigated by means of transmission electron microscopy (TEM), Auger electron and X-ray photoelectron spectroscopy (AES, XPS), the latter in two different operating modes, standard and angle resolved mode. In addition, confocal microscopy and focused ion beam cutting were used for structural studies of the surfaces and for specimen preparation. The results illustrate in detail the strengths and weaknesses of each measurement technique. TEM offers a direct way to reliably quantify the thickness of the oxide layer, which is in the range of 5 nm, however, on a laterally restricted area of the surface. In comparison, for AES, the destructiveness of the electron beam did not allow to achieve comparable results for the thickness determination. XPS was proven to be the most reliable method to reproducibly quantify the average oxide thickness. By evaluating the angle resolved XPS data, additional information on the average depth distribution of the individual elements on the surface could be obtained. The findings obtained in this study were then successfully used for the investigation of the increase in the aluminium oxide thickness on technical samples during an aging test of 12 months under standard storage conditions.