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The effects of wood temperature, cutting width, and knots on the surface quality of black spruce cants processed by a chipper-canter were evaluated. Four matched groups of logs were machined at temperatures of 20°C, 0°C, −10°C, and −20°C. Each log was transformed at two cutting widths (CW: 12.7 and 25.4 mm). Knot characteristics were measured on the cant surfaces after log processing. Surface quality of cants was assessed by roughness and waviness parameters and torn grain. The quality of surfaces was affected by the temperature of logs and cutting width. Poorer surface quality was obtained at larger cutting widths. This was caused by increased cutting forces when processing more material at larger cutting widths, compounded by the presence of knots. Waviness and roughness were higher for frozen logs than for unfrozen logs. Although the sub-zero temperatures caused higher cutting forces and vibrations, their effect was partly offset by the strengthening of the earlywood and the brittle behaviour of frozen wood. Correlations and regression analyses showed that the optimisation of the cutting conditions for decreasing waviness and roughness should also reduce the torn grain depth. Moreover, the position and area of knots could be considered to minimise waviness and roughness and the occurrence of torn grain. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical properties of a modified Body-Centred Cubic lattice cell with waved struts have been determined using FEM simulations with solid element mesh. The strut waviness introduces orthotropic properties in the cell and the correlation between geometrical cell parameters and resulting mechanical attitudes is calculated. For a complete determination of all the mechanical constants, uniaxial compression and in-plane shear have been simulated along different loading directions. Attention has been particularly paid to the definition of appropriate boundary constraints able to mimic the periodic condition that applies to a repetitive unit cell. At first, the numerical model has been validated with existing analytical and experimental results available in the literature, then parametric strut waviness has been introduced to this model. A systematic numerical study has been conducted on lattice cells with different density and different wave amplitude. Results have evidenced for the waved struts a considerable increase in the longitudinal uniaxial modulus and a negligible effect on the transverse moduli, while a slight reduction of the shear moduli is generally obtained in all the sliding planes. Poisson's ratios are highly affected both by density and waviness. The obtained results can be useful for the optimized definition of a lattice cell, tailored to the specific mechanical requirements of an advanced component. [ABSTRACT FROM AUTHOR]

The moisture content of wood influences its machinability and the resulting quality of the machined surface. This study aims to explore the impact of varied moisture content on the final quality of beech wood cut by a CO2 laser (Fagus sylvatica L.). Laser cutting was performed on beech lumbers conditioned at moisture levels of 0%, 8%, 12%, and 18%. The laser-cut specimens were evaluated for surface roughness and waviness by using a stylus surface profilometer at three measuring locations: top, middle, and bottom. The total color difference ΔE was also assessed using a spectrophotometer at the same three locations. The most intriguing findings revealed that surface specimens with higher moisture content are lighter than those with lower moisture content. Specifically, the top areas of specimens with different moisture content exhibited lighter shades than those in the middle and bottom areas. Notably, the surface profile of the specimens remained unaffected by variations in moisture content levels. [ABSTRACT FROM AUTHOR]

This paper proposes a novel four degrees of freedom model of angular contact ball bearings (ACBBs) under high-speed effect, in order to characterize the dynamic behavior of rolling bearings with coupling waviness and local defects on the outer race in detail. Firstly, based on bearing quasi-static model, considering centrifugal force, gyroscope moment, the bearing contact stiffness is calculated. Then, the representation model of outer race waviness and the time-varying displacement excitation expression of the bearing with local defects are put forward respectively. On the basis, a dynamic model of ACBBs with coupling factors is built. Finally, the vibration characteristics of the bearing with faults are investigated, the model is verified by the existing experimental results and the influence of different parameters on the bearing dynamics is analyzed. The results show that the bearing fault characteristic frequency is unchanged when the high-speed effect is considered, but the vibration amplitude is smaller than that without the high-speed effect. With the increase of speed, the bearing fault characteristic frequency and vibration amplitude increase. When considering the coupling of outer race waviness and local defects, with the increase of the two factors, the bearing fault characteristic frequency remains unchanged but the vibration amplitude increase. [ABSTRACT FROM AUTHOR]

A vectorized analytical model for the cutting dynamics in the spiral bevel gear face hobbing process has been developed, which is based on machine tool kinematics and vibration vectorization. The structural modal parameters of the cutter head spindle system are obtained through experimental modal analysis with hammer impact testing. The analytical model is utilized to simulate the generation of simulated vibration acceleration signals during spiral bevel gear hobbing. A wavelet threshold denoising method is applied to process the simulated vibration signals of the spiral bevel gear face hobbing with added white noise. Signal processing methods, including short-time Fourier transform are employed for time-domain analysis, frequency-domain analysis, and time–frequency-domain analysis of measured signals and simulated signals, thereby extracting the corresponding statistical features. In addition to the results of the experimental modal analysis, the causes of chatter in spiral bevel gear hobbing are discussed in detail, revealing that the main factor is cutter head vibration in the Y direction of the Hunan ZDCY CNC EQUIPMENT YKA2260 machine tool used in this research. The error in the time-domain characteristic parameters between simulated signals and measured vibration acceleration signals is within 15%, with a difference of 3.5% in spectral peak values. The predicted tooth surface morphology from simulation matches the actual morphology on the workpiece, comprehensively validating the reliability of the cutting dynamics model for the spiral bevel gear face hobbing process. Another conclusion drawn from numerical simulation experiments is that the amount of tooth surface waviness of the spiral bevel gears is the ratio of tool chatter frequency to cutting fundamental frequency. [ABSTRACT FROM AUTHOR]

Despite the significant socioeconomic implications in the link between atmospheric waviness and extreme weather events, future atmospheric waviness trends remain elusive due to uncertainties arising from diverse definitions and insufficient dynamical formalism in existing metrics. This study employs a local wave activity (LWA) metric, whose prognostic equation links wave activity changes to forcing mechanisms, to assess wintertime Northern Hemisphere waviness in ERA5 and HighResMIP data sets. The models generally exhibit high fidelity in reproducing observed waviness, while biases stem primarily from biases in the LWA source, low‐level meridional heat flux, which tend to improve with higher resolutions. Future projections exhibit reduction in LWA, primarily due to suppressed LWA generation, which is mitigated by higher‐resolution models. We found that both biases and reduction of the LWA source are closely associated with sensible heat fluxes from the ocean to the atmosphere, highlighting the potential impacts of resolving ocean currents. Plain Language Summary: This study investigates atmospheric waviness in the Northern Hemisphere during winter, using a measure called local wave activity, which enables identifying causes behind waviness changes. Applying this metric to various climate models with different resolutions and a reanalysis data set, we found that historical simulations by the models generally well capture the observed climatological waviness. Biases are found over Europe and mid‐latitudes in Eurasia and the Pacific, which generally improve with higher‐resolution models. In the future simulation, reduction in waviness over much of the Northern Hemisphere, especially in the Atlantic and Pacific sectors, due to a decreased waviness source is found. Higher‐resolution models mitigate this reduction over North Atlantic. Our findings emphasize the connection between waviness and heat given from the ocean to the atmosphere, highlighting the importance of higher ocean resolution for accurate future waviness projections. This study underscores the significant role of the ocean in shaping atmospheric waviness and its implications for climate predictions. Key Points: Biases in Northern Hemisphere wintertime climatological waviness in historical runs are mostly ameliorated with high‐resolution modelsFuture Northern Hemisphere winter waviness will undergo a general reduction, which is mitigated by high‐resolution models over North AtlanticSensible heat fluxes play a crucial role in both historical biases and future reductions in waviness, highlighting the key role of the ocean [ABSTRACT FROM AUTHOR]

The effects of cutting speed (CS) and feed-per-knife (FK) on the surface quality of black spruce (Picea mariana [Mill.] B.S.P.) cants processed by a chipper-canter were evaluated. Nine matched groups of logs were studied at 20, 25, and 30 m/s of CS, and 19, 25, and 32 mm of FK. Each log was processed at frozen and unfrozen conditions. Knots and grain angle measurements were taken on the cant surfaces after machining. The quality of cants was assessed utilizing waviness, roughness, and torn grain. The results showed that the surface quality was affected by CS and FK. Surface quality improved as FK decreased, likely due to decreasing cutting forces. The waviness tended to improve as CS increased, which could be partly due to the reduction of the non-cutting period between knives at higher CS. The waviness and depth of torn grain were similar for frozen and unfrozen logs. Surface quality varied within the cant, being generally poorer in the lower half. Knots and orientation of spiral grain (left-handed) contributed to diminishing the quality of surfaces. Finally, the results of correlations and regression analyses showed that optimizing the cutting conditions to decrease waviness should also reduce the depth of torn grain. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) nanoplatelets can be used to reinforce neat resin or the matrix phase of fiber composites for improved mechanical properties. Although the oxygen content levels in GO and reduced graphene oxide (rGO) strongly influence the interface with the polymer, experimental-based optimization of the oxygen content for enhanced composite properties is difficult and time-consuming. Fortunately, molecular dynamics (MD) simulation can be used to efficiently predict the interfacial properties of composite on the molecular level and provide physical insight into the effect of the oxygen content of rGO. In this study, MD is used to predict the elastic properties of rGO/epoxy interfaces and the corresponding interfacial shear strength (IFSS) for different oxygen content levels. The results indicate that increasing levels of oxygen in rGO results in interfaces with a reduced in-plane elastic modulus but a substantially higher IFSS. These results are important for the design of rGO/epoxy composites for specific engineering applications. [ABSTRACT FROM AUTHOR]

Abrasive waterjet (AWJ) machining offers the possibility of creating a wide range of features on mechanical parts with different degrees of complexity with a relatively high efficiency. However, after the roughing passes, the surface quality of features such as blind pockets is rather low, with unfavorable implications for surface waviness and form deviations apart from high surface roughness. Apart from the traditional methods for finishing, such as grinding or lapping, it is worth attempting either to improve the surface quality obtained during roughing by an AWJ or to integrate a post-processing step by using a pure WJ in the existing process in order to ameliorate the surface quality. Thus, in the current study, the effect of pure waterjet (WJ) post-processing of machined pockets by AWJ milling on a Ti-6Al-4V workpiece using recycled glass beads was investigated under different conditions. The findings indicate that although the different post-processing treatments by a pure WJ can affect the surface quality on average, these differences are not considerably important, probably due to an insufficient capability of material removal, which hinders the smoothing effect on machined surfaces. Thus, it was indicated that a higher number of post-processing passes under different conditions than those of the roughing pass can be more favorable for efficient post-treatment by a pure WJ. [ABSTRACT FROM AUTHOR]

This work explores the feasibility of nonlinear behavior of doubly clamped single-walled boron nitride nanotube (SW-BNNT)-based nanoresonator. A nonlinear mathematical model of wavy SW-BNNT has been developed for analyzing the geometrical nonlinearity. Dynamic responses of nonlinear model have been analyzed for different waviness factors varying from 0.01 to 0.06 using various tools like time series, phase space, Poincaré map and Fast Fourier Transforms (FFTs). For the analysis, 20 nm length of SW-BNNT has been considered. It has been observed from nonlinear analysis, that for responses with a lower value of waviness (e.g., 0.01) for 20 nm long BNNT, the system's nature loses its periodicity and shows onset of chaos with dense spectrum in Poincaré maps and irregular pattern in time response. Thus, it is concluded that chaotic response with a less strange attractor has been observed when waviness is 0.01. It is also concluded that, with increase in waviness factor from 0.02 to 0.06, the system showed the multi-periodic response with 2-T, 3-T and 4-T periods. The dynamic responses with varying waviness showed that the system behavior is changing from chaotic to periodic. This change in periodicity is one of the characteristics of chaotic solution. [ABSTRACT FROM AUTHOR]

We previously developed a simplified finite element (FE) "unit" model to reproduce the mechanical interaction between the smooth muscle layer and elastic lamina (EL) in the aortic media. Nevertheless, whether this simplified FE model can represent the structure of a real medial wall and whether its modeling technique can help in developing a highly sophisticated and structure-based aortic FE model should be determined. Therefore, this study aimed to computationally represent EL buckling in the aortic medial ring at an unloaded state based on the integrated unit models and reproduce transmural variations in EL waviness across the vascular wall. We confirmed that the inner and outer layers of the medial wall were relatively subjected to compressive and tensile residual stresses, respectively, at the unloaded state, implying that the ring model will open spontaneously when it is radially cut. In addition, the residual stresses computed under such a stress-free condition were comparable to the analytically estimated values, partially supporting the validity of our modeling approach. Although further study is still required, the information obtained in this study will greatly improve the understanding of basic aortic physiology and pathophysiology and provide a basis for performing more sophisticated computational modeling of the aortic wall. [ABSTRACT FROM AUTHOR]

The cylindrical mold is a key element utilized in the manufacture of different cylindrical components for a wide range of applications in industries like automotive, aerospace, medical, and among others. Fine finishing of the cylindric mold with high surface integrity has several benefits such as good fits and tolerance, increased product quality, and high load-bearing capability for components. Recently, a cutting-edge rotating magnetorheological honing (RMRH) method based on permanent magnet tools was developed for the fine finishing of interior cylindrical surfaces with great productivity. Furthermore, many industrial real-time cylindrical molds need to be fine-finished with high productivity to enhance their functionality. To meet these requirements, the RMRH procedure could be the better option. Therefore, the RMRH process is investigated in the current study to finely finish the inner surface of the real-time EN-8 steel mold for plastic bottle caps. To determine how well the real-time EN-8 steel cylindrical mold could be fine-finished using the current process, the response surface technique was used to know the best finishing parameters. The significant % drop in parameters of the surface roughness profile (Ra, Rz, and Rq) of the MR finished real-time EN8 mold surface is achieved as 86.05, 82.17, and 84.62, respectively, after 40 minutes of the RMRH process with the optimal parameters. Also, a considerable improvement in straightness is obtained as the final surface waviness on the inside cylindrical surface of the real-time EN8 mold for plastic bottle caps is decreased from an initial value of 120 nm to 40 nm. Further, circularity and surface morphology tests are carried out over the mold's finished inner surface. After providing the efficient MR finishing using the current process, results indicate that surface properties and functional efficacy of the internal surface of the real-time mold for producing plastic bottle caps have improved. [ABSTRACT FROM AUTHOR]

During the production of components, manufacturers of structures are obliged to meet certain requirements and ensure appropriate quality characteristics. It is especially important during the manufacturing of thin-walled structures, which are subject to many errors during machining due to the reduced rigidity of the products, including the deformation of thin walls, which may be the result of the vibration of the system. The appearance of vibrations reduces the quality of the machined surface affecting the increase in the values of surface topography parameters—waviness and roughness. Thin-wall structures—titanium or nickel alloy, among others—play a key role in the aerospace industry, which constantly strives to reduce the weight of the entire structure while meeting requirements. The present work focuses on the evaluation of the parameters of surface topography, dimensional and shape accuracy during the milling of nickel alloy Inconel 625 samples containing a thin wall in a vertical orientation. The experiment was conducted under controlled cutting conditions using a constant material removal rate. As part of the surface topography section, the distribution of waviness, Wa and Wz, and roughness, Ra and Rz, was determined in selected measurement areas in the direction parallel to the direction of the feed motion. Dimensional deviations, measured with a 3D optical scanner, were determined in selected cross sections in the direction perpendicular and parallel to the bottom of the sample presenting the deflection of the thin-walled structure. The results provide information that the used parameter sets affect the measured quantities to varying degrees. [ABSTRACT FROM AUTHOR]

The evaluation of surface quality after milling still represents a challenge due to the stratified structure of wood. In this paper, the surface quality of beech wood obtained by profile milling was analyzed differentiating between tool marks, fuzzy grain, and accidental surface gaps overlapped onto the deep anatomical cavities. The samples were milled at two rotation speeds, 3308 rpm (n1) and 6594 rpm (n2), and two feed speeds of 6.53 m/min (vf1) and 23.74 m/min (vf2). After the samples were cut, approximately 600 m of beech wood were further processed before measuring the surface quality again. The surface waviness measured by Wa increased more than double when the feed speed increased from vf1 to vf2. Rk increased with the feed speed (with the feed per tooth, fz, for a constant n, respectively) for n2 by a significant 57%. An increase in the rotation speed from n1 to n2 has reduced Rk, but the effect was not significant. The processing quality, Rk, measured at different depths did not differ statistically, in spite of the local differences in the cutting speed. The moment of measuring the surface roughness, such as immediately after sharpening or after a working period, influenced the surface quality. After the tool processed 600 m of beech material, the surface quality improved by 30%. The statistical analysis showed that the most important factor affecting the surface quality was the feed speed (implicitly fz, for constant n and number of cutters). [ABSTRACT FROM AUTHOR]

This study investigates the relationship between measured gloss and the microstructure of printed UV-inks containing aluminum pigments. Using a laboratory flexo printing machine, UV-inks containing leafing-type vacuum metallized pigments were printed onto Chromolux paper and primed MultiArt Gloss paper. The time between printing and curing of the ink (dwell time) was varied between the experimental runs. For some samples, hot air was applied onto the uncured UV-ink during the dwell time. The influence of heat (hot air) and dwell time on gloss and the topography of the pigment layer as well as the influence of the substrate was investigated. Roughness and waviness data were obtained using a confocal microscope (Sensofar PLu Neox), gloss measurements were obtained using an IQ-S gloss meter. It was shown that a longer dwell time as well as hot air has a positive influence on the specular gloss measured on the metallic ink printed on Chromolux paper. Also, good correlations could be found between specular gloss, roughness, and waviness, respectively. For primed Multi Art Gloss paper, however, a longer dwell time and hot air can have a negative influence on specular gloss. Also, correlations between roughness, waviness and specular gloss are not as strong as for Chromolux paper. [ABSTRACT FROM AUTHOR]

The nanocomposites reinforced by carbon nanotubes (CNTs) exhibit great advantages in many fields. Many scholars focused on evaluating elastic properties of nanocomposites. There are somewhat disagreements between theoretical and experimental results. The waviness of the nanotubes is considered as one important factor affecting on the effective elastic modulus of nanocmposites. The present paper aims to develop a new model to replace the wavy carbon nanotubes with "effective fiber". With the help of "effective fiber", the effective modulus of nanocomposites with randomly oriented tubes can be predicted based on the micromechanics. In this study, the Mori-Tanaka effective-field method is modified, and the analytical expressions are derived for the effective elastic modulus of carbon nanotube-reinforced composites. The effects of waviness and agglomeration on the effective modulus are also analyzed. It is shown that they can reduce the stiffness of carbon nanotubes, significantly. Moreover, the effective elastic modulus of nanocomposites is very sensitive to the waviness and agglomeration. [ABSTRACT FROM AUTHOR]

Titanium and nickel alloys are used in the creation of components exposed to harsh and variable operating conditions. Such components include thin-walled structures with a variety of shapes created using milling. The driving factors behind the use of thin-walled components include the desire to reduce the weight of the structures and reduce the costs, which can sometimes be achieved by reducing the machining time. This situation necessitates, among other things, the use of new machining methods and/or better machining parameters. The available tools, geometrically designed for different strategies, allow working with similar and improved cutting parameters (increased cutting speeds or higher feed rates) without jeopardizing the necessary quality of finished products. This approach causes undesirable phenomena, such as the appearance of vibrations during machining, which adversely affect the surface quality including the surface roughness. A search is underway for cutting parameters that will minimize the vibration while meeting the quality requirements. Therefore, researching and evaluating the impact of cutting conditions are justified and common in scientific studies. In our work, we have focused on the quality characteristics of horizontal thin-walled structures from Ti6Al4V titanium alloys obtained in the milling process. Our experiments were conducted under controlled cutting conditions at a constant value of the material removal rate (2.03 cm3⁄min), while an increased value of the cut layer was used and tested for use in finishing machining. We used three different cutting tools, namely, one for general purpose machining, one for high-performance machining, and one for high-speed machining. Two strategies were adopted: adaptive face milling and adaptive cylindrical milling. The output quantities included the results of acceleration vibration amplitudes, and selected surface topography parameters of waviness (Wa and Wz) and roughness (Ra and Rz). The lowest values of the pertinent quantities were found for a sample machined with a high-performance tool using adaptive face milling. Surfaces typical of chatter vibrations were seen for all samples. [ABSTRACT FROM AUTHOR]

Abstract Despite the significant socioeconomic implications in the link between atmospheric waviness and extreme weather events, future atmospheric waviness trends remain elusive due to uncertainties arising from diverse definitions and insufficient dynamical formalism in existing metrics. This study employs a local wave activity (LWA) metric, whose prognostic equation links wave activity changes to forcing mechanisms, to assess wintertime Northern Hemisphere waviness in ERA5 and HighResMIP data sets. The models generally exhibit high fidelity in reproducing observed waviness, while biases stem primarily from biases in the LWA source, low‐level meridional heat flux, which tend to improve with higher resolutions. Future projections exhibit reduction in LWA, primarily due to suppressed LWA generation, which is mitigated by higher‐resolution models. We found that both biases and reduction of the LWA source are closely associated with sensible heat fluxes from the ocean to the atmosphere, highlighting the potential impacts of resolving ocean currents.

AMOLED flexible display are becoming popular, but the waviness in the middle of the display screen has greatly affected the user experience. Waviness will become more visible with the usage time, which is still the main concern of foldable products in the display industry. But the middle crease has become one of the main reasons why the sales of folding mobile phones have not been popular as present, mainstream mobile phone and screen manufacturers are in the analysis stage of Waviness mechanism. Therefore, this article mainly analyzes the causes of waviness in the folding screen from multiple factors, and draws its main influence mechanism. In this paper, based on the theoretical analysis and simulation results, the development direction of Film and OCA properties is proposed, which provides the possibility for the waviness‐free foldable AMOLED display. [ABSTRACT FROM AUTHOR]

With the market for organic light‐emitting diodes expanding, the devices' cushioning capabilities and lightweight design are attracting more attention and causing issues. In this study, a unique type of pressure‐sensitive silicone adhesive is proposed. Meanwhile, a damping silicone pressure‐sensitive adhesive is added to the light‐emitting diode module, increasing its drop height from 40 to 55 mm and satisfying the controlled demand for the cushioning quality. [ABSTRACT FROM AUTHOR]

A vectorized analytical model for the cutting dynamics in the spiral bevel gear face hobbing process has been developed, which is based on machine tool kinematics and vibration vectorization. The structural modal parameters of the cutter head spindle system are obtained through experimental modal analysis with hammer impact testing. The analytical model is utilized to simulate the generation of simulated vibration acceleration signals during spiral bevel gear hobbing. A wavelet threshold denoising method is applied to process the simulated vibration signals of the spiral bevel gear face hobbing with added white noise. Signal processing methods, including short-time Fourier transform are employed for time-domain analysis, frequency-domain analysis, and time–frequency-domain analysis of measured signals and simulated signals, thereby extracting the corresponding statistical features. In addition to the results of the experimental modal analysis, the causes of chatter in spiral bevel gear hobbing are discussed in detail, revealing that the main factor is cutter head vibration in the Y direction of the Hunan ZDCY CNC EQUIPMENT YKA2260 machine tool used in this research. The error in the time-domain characteristic parameters between simulated signals and measured vibration acceleration signals is within 15%, with a difference of 3.5% in spectral peak values. The predicted tooth surface morphology from simulation matches the actual morphology on the workpiece, comprehensively validating the reliability of the cutting dynamics model for the spiral bevel gear face hobbing process. Another conclusion drawn from numerical simulation experiments is that the amount of tooth surface waviness of the spiral bevel gears is the ratio of tool chatter frequency to cutting fundamental frequency.

In the present study, the bending analysis of multi walled carbon nanotubes (MWCNTs) reinforced laminated tapered spherical composite panels subjected to transverse loading conditions is carried out using the finite element method (FEM) with displacement fields derived from high order shear deformation theory. In this regard, the elastic properties of the polymeric nanocomposite, considering the MWCNTs agglomeration, waviness and interphase thickness between the MWCNTs and polymer matrix were computed by employing various micromechanical approaches. Subsequently, glass-fiber were introduced as a reinforcement phase, and the overall elastic properties of a three-phase MWCNT/fiber/polymer hybrid nanocomposite material were obtained using Chamis model. The accuracy of the developed FE formulation were verified using the experimental and numerical data available in the open literature. After verification, the deflection and stresses of the panel are numerically determined for various taper configurations. Further, detailed parametric analysis is carried out to explore the influence of various parameters such as CNT content, agglomeration, waviness, interphase area, thickness ratio, curvature ratio and taper configurations on the bending results of laminated tapered spherical panels. It was observed that an increase in the weight fraction of CNTs, an equal number of agglomeration parameter and the thickness of the interphase have a positive effect in minimizing the deflection and stresses. It was also observed that the TC-2 and TC-3 taper configurations results the highest and lowest deflection. Finally, it can be concluded the current work can serve as a guide for the effective design and development of CNT reinforced composite structures. [ABSTRACT FROM AUTHOR]

It is of great significance for improving the precision and error analysis of the aircraft altitude measurement system to accurately understand the influence of aircraft nose skin waviness on the flow around the total static pressure probe and the pressure of the measuring hole. The effect of the nose skin waviness on the hole pressure of the total static pressure probe was studied by using computational fluid dynamics method. The numerical simulation method was verified based on the single probe configuration. For a single air-craft nose configuration, the influence of skin waviness on the pressure in the spatial area near the pre-installation position of the probe was studied. For the combination configuration of the probe and aircraft noses, including the theoretical aircraft nose and the waviness nose, the influence of the skin waviness on the flow around the total static pressure probe and the pressure at the measuring hole was studied. The results show that the numerical simulation method can meet the requirements of the numerical simulation of the flow field around the total static pressure probe on the nose surface. The influence of the waviness on the pressure coefficient at the measuring hole of the probe increases with the increase of Mach number. For a fixed Mach number, the influence of waviness decreases with the increase of the angle of attack at the first group of pressure measuring holes, and increases first and then decreases with the increase of the angle of attack at the second group of pressure measuring holes. [ABSTRACT FROM AUTHOR]

This paper relates to the selection of a machine learning model for predicting the surface waviness of rolled products. An experimental study was carried out using the skew rolling method with three tapered rolls. The products were shaped with variable process parameters. The obtained results were used as a training data set for selected regression models. The random forest model was determined to be the most effective due to the highest value of the coefficient of determination R2. The influence of individual process parameters on the waviness value was calculated using the SHAP library. [ABSTRACT FROM AUTHOR]

Seersucker woven fabrics are characterized by their unique structure and properties. Surface topography is a crucial feature of the seersucker woven fabrics. It influences the appearance and performance of fabrics. Till now, no testing method has been developed to assess the seersucker woven fabrics from the point of view of their surface geometry and to quantify the seersucker effect. In the present work, the non-contact optical method has been used to determine the parameters and functions characterizing the surface geometry of the cotton seersucker woven fabric. The aim of this work was to analyse the possibility of use of the MicroSpy® Profile profilometer in complex characterization of the investigated fabric and separately the flat and puckered areas of the fabric. The obtained results confirmed that the selected surface parameters and functions are able to distinguish both phases of the seersucker woven fabric: flat and puckered. The results are the starting point for further investigations of the seersucker woven fabrics in order to quantify the seersucker effect. [ABSTRACT FROM AUTHOR]

For the slicing of superhard silicon nitride ceramics, diamond wire sawing technology has great potential for application, and its slicing surface characteristics are an important indicator of cutting quality. In this paper, the sawing experiments of silicon nitride ceramics were carried out within the range of industrial processing parameters of diamond wire sawing (saw wire speed: 800–1600 m/min, workpiece feed speed 0.1–0.4 mm/min). The effects of cutting parameters on the surface morphology, surface roughness and waviness of the as-sawn slices were analyzed. The results show that within the range of sawing parameters for industrial applications, the material on the diamond wire as-sawn surface of silicon nitride ceramics is removed mainly in a brittle mode, with the slice morphology showing brittle pits and regularly distributed wire marks in the 20–55 μm scale range. The surface roughness of the slices along the workpiece feed direction ranges from 0.27 to 0.38 μm and decreases with increasing saw wire speed and decreasing feed rate. The surface waviness ranges from 0.09 to 0.21 μm, which is in good agreement with the changing trend of the sliced-surface roughness. The results of the study provide an experimental reference for promoting the engineering application of diamond wire sawing technology to the processing of silicon nitride ceramic slices. [ABSTRACT FROM AUTHOR]

The evaluation of waviness, also known as orange peel, is essential for the quality control of materials in industrial fields working with high gloss materials, e.g., coatings, automotive and metal fabrication. This paper presents an affordable noncontact method for waviness analysis based on a single image of the light source reflected from the surface under study. The spatial perturbations along the contour of the light source reflection are compared to the ideal contour and analyzed in the Fourier domain to obtain standard features that have been compared to commercial ripple characterization device. Additional three method-specific features are proposed and evaluated. Our method has been tested on a set of ten orange peel standards, ten effect, and three solid coating samples and shows promising performance in waviness characterization of glossy surfaces. [ABSTRACT FROM AUTHOR]

The Boron Nitride Nanotube (BNNT) is capable of sensing the masses even below the zeptogram level when it is used as a resonator. The surface of BNNT is considered to be straight in most of the existing literatures. In this work, wavy surface of BNNT is considered, and its effect on the mass sensing capabilities of BNNT is investigated. A nonlinear mathematical model is developed by applying the continuum mechanics approach on surface deviated (wavy) BNNT of a hollow cylindrical geometry with thin wall. The model is normalized to the nanoscale level, and the degrees of nonlinearity arise due to waviness are identified in BNNT mass sensing application. The deformation in nanostructures is nonlinear that causes oscillations of large amplitude. The midplane stretching and waviness factor of a single walled BNNT, which is clamped at both of its end, are considered to investigate its frequency response to the attached mass. It is proposed to include waviness surface of BNNT to develop more accurate biomass sensor. It is further found that there is a shift in the resonance frequency due to surface waviness of BNNT as compared to straight BNNT. The future perspective of this study is to investigate methods to optimize the wavy structure of BNNTs for improved biomolecule detection. This could involve studying the effect of different wave patterns, sizes, and amplitudes on the sensor's sensitivity and selectivity.

Among all the structural formations, fiber-like structure is one of the most common modalities in organisms that undertake essential functions. Alterations in spatial organization of fibrous structures can reflect information of physiological and pathological activities, which is of significance in both researches and clinical applications. Hence, the quantification of subtle changes in fiber-like structures is potentially meaningful in studying structure-function relationships, disease progression, carcinoma staging and engineered tissue remodeling. In this study, we examined a wide range of methodologies that quantify organizational and morphological features of fibrous structures, including orientation, alignment, waviness and thickness. Each method was demonstrated with specific applications. Finally, perspectives of future quantification analysis techniques were explored. [ABSTRACT FROM AUTHOR]

Abrasive wear can have a detrimental effect on machinery, especially in the mining and construction industries. To prolong machinery lifetime and cut down energy consumption, a thorough understanding of abrasive wear is essential: surface topography measurement and interpretation (including form, waviness, and roughness) are vitally important. However, the potentially crucial influence of surface topography intricacies on tribological behavior has been obscured since roughness and waviness are considered simple scalar quantities in most cases (e.g., roughness Ra and waviness Wt). In this work, the complete waviness profile of the sliding track was used to shed light on the influence of surface topography on abrasive wear. Bearing steel (100Cr6, AISI 52100) pins and disks were tribologically tested in a flat-on-flat contact with Al2O3-based slurries as interfacial medium. Using slurries with two different particle sizes, 5 and 13 μm, we found that friction fluctuates only with small abrasive particles (5-µm slurry) and relatively low waviness disks. It was found that even small surface deviations (albeit minimized and controlled for) can significantly increase the friction coefficient—up to 91%. Remarkably, not only are frictional fluctuations strongly correlated with the disk’s initial waviness profile, but these small fluctuations correlate with unevenly distributed high wear. These findings enhance our understanding of the friction wear structure and provide the basis for exploring how surfaces can be optimized for better tribological performance. [ABSTRACT FROM AUTHOR]

A simple method for determining the effective elastic modulus of wavy single-wall carbon nanotubes (SWCNTs) is presented in this paper. The effective modulus of curved SWCNTs is derived using Castigliano's theorem. The effect of curvature on the effective modulus is studied. This method is verified by finite element analysis (FEA). The distributions of effective moduli are studied by Monte Carlo simulation. The effective modulus of a general wavy SWCNT is derived by considering the SWCNT as a number of curved SWCNT sections. [ABSTRACT FROM AUTHOR]

Seersucker woven fabrics are characterized by their unique structure and properties. Surface topography is a crucial feature of the seersucker woven fabrics. It influences the appearance and performance of fabrics. Till now, no testing method has been developed to assess the seersucker woven fabrics from the point of view of their surface geometry and to quantify the seersucker effect. In the present work, the non-contact optical method has been used to determine the parameters and functions characterizing the surface geometry of the cotton seersucker woven fabric. The aim of this work was to analyse the possibility of use of the MicroSpy® Profile profilometer in complex characterization of the investigated fabric and separately the flat and puckered areas of the fabric. The obtained results confirmed that the selected surface parameters and functions are able to distinguish both phases of the seersucker woven fabric: flat and puckered. The results are the starting point for further investigations of the seersucker woven fabrics in order to quantify the seersucker effect.

Because of the time-dependent characteristics of the polymers, carbon nanotube (CNT)-reinforced polymer nanocomposites exhibit great viscoelastic nature. Besides, it also has advantages in strength and stiffness. Therefore, a sufficient understanding of their rheological behavior is necessary if the materials are to be used in the aerospace industry. The paper's objective is to track the vibrational responses of a multi-scale hybrid nanocomposite beam for the first time while accounting for the wavy form and the time dependency of the polymer. To do this, the homogenization process combines the mix-ture's rule with the modified Halpin-Tsai model. The results demonstrate that assigning a large value to the polymer's characteristic relaxation time may delay the structure's vibration suppression. Furthermore, the results show that hybrid nanocomposites made of wavy CNTs are unable to offer optimal frequencies in comparison to those produced from straight CNTs. [ABSTRACT FROM AUTHOR]

Among all the structural formations, fiber-like structure is one of the most common modalities in organisms that undertake essential functions. Alterations in spatial organization of fibrous structures can reflect information of physiological and pathological activities, which is of significance in both researches and clinical applications. Hence, the quantification of subtle changes in fiber-like structures is potentially meaningful in studying structure-function relationships, disease progression, carcinoma staging and engineered tissue remodeling. In this study, we examined a wide range of methodologies that quantify organizational and morphological features of fibrous structures, including orientation, alignment, waviness and thickness. Each method was demonstrated with specific applications. Finally, perspectives of future quantification analysis techniques were explored.

The formation of waviness on the working surfaces of bearing parts is associated with fluctuations in the size of the cut layer of metal and changes in the components of the cutting force. Laplace operators were used to model the centerless grinding system based on the construction of the transfer function and the characteristic equation. It was found that the formation of waviness depends on the position of the hodograph of the movement of the vector of the center of the part in the complex plane, which in turn depends on the geometric parameters of the rigid supports of the centerless grinder machine. This makes it possible, based on hodographs and the angular orientation of their asymptotes, to determine the geometric stability of the process depending on the angles of adjustment of the rigid supports of the grinder machine. Two methodological approaches were used to confirm the correctness of the hypotheses. The first one is a multiplication of wave’s hodographs. The second one is regeneration displacement and the coincidence of the combined hodograph of regeneration and waviness displacement mechanisms with the hodograph of infinitely rigid machine displacement. The diagrams which allow choosing geometry of adjustment of rigid support that allows to increase or decrease parameters of certain harmonics are developed. The 3D diagram allows setting the local minima, characterized by acceptable geometric adjustment conditions, providing regulated waviness of the working surfaces of bearing parts.

Abrasive waterjet (AWJ) machining offers the possibility of creating a wide range of features on mechanical parts with different degrees of complexity with a relatively high efficiency. However, after the roughing passes, the surface quality of features such as blind pockets is rather low, with unfavorable implications for surface waviness and form deviations apart from high surface roughness. Apart from the traditional methods for finishing, such as grinding or lapping, it is worth attempting either to improve the surface quality obtained during roughing by an AWJ or to integrate a post-processing step by using a pure WJ in the existing process in order to ameliorate the surface quality. Thus, in the current study, the effect of pure waterjet (WJ) post-processing of machined pockets by AWJ milling on a Ti-6Al-4V workpiece using recycled glass beads was investigated under different conditions. The findings indicate that although the different post-processing treatments by a pure WJ can affect the surface quality on average, these differences are not considerably important, probably due to an insufficient capability of material removal, which hinders the smoothing effect on machined surfaces. Thus, it was indicated that a higher number of post-processing passes under different conditions than those of the roughing pass can be more favorable for efficient post-treatment by a pure WJ.

During the production of components, manufacturers of structures are obliged to meet certain requirements and ensure appropriate quality characteristics. It is especially important during the manufacturing of thin-walled structures, which are subject to many errors during machining due to the reduced rigidity of the products, including the deformation of thin walls, which may be the result of the vibration of the system. The appearance of vibrations reduces the quality of the machined surface affecting the increase in the values of surface topography parameters—waviness and roughness. Thin-wall structures—titanium or nickel alloy, among others—play a key role in the aerospace industry, which constantly strives to reduce the weight of the entire structure while meeting requirements. The present work focuses on the evaluation of the parameters of surface topography, dimensional and shape accuracy during the milling of nickel alloy Inconel 625 samples containing a thin wall in a vertical orientation. The experiment was conducted under controlled cutting conditions using a constant material removal rate. As part of the surface topography section, the distribution of waviness, Wa and Wz, and roughness, Ra and Rz, was determined in selected measurement areas in the direction parallel to the direction of the feed motion. Dimensional deviations, measured with a 3D optical scanner, were determined in selected cross sections in the direction perpendicular and parallel to the bottom of the sample presenting the deflection of the thin-walled structure. The results provide information that the used parameter sets affect the measured quantities to varying degrees.

The evaluation of surface quality after milling still represents a challenge due to the stratified structure of wood. In this paper, the surface quality of beech wood obtained by profile milling was analyzed differentiating between tool marks, fuzzy grain, and accidental surface gaps overlapped onto the deep anatomical cavities. The samples were milled at two rotation speeds, 3308 rpm (n1) and 6594 rpm (n2), and two feed speeds of 6.53 m/min (vf1) and 23.74 m/min (vf2). After the samples were cut, approximately 600 m of beech wood were further processed before measuring the surface quality again. The surface waviness measured by Wa increased more than double when the feed speed increased from vf1 to vf2. Rk increased with the feed speed (with the feed per tooth, fz, for a constant n, respectively) for n2 by a significant 57%. An increase in the rotation speed from n1 to n2 has reduced Rk, but the effect was not significant. The processing quality, Rk, measured at different depths did not differ statistically, in spite of the local differences in the cutting speed. The moment of measuring the surface roughness, such as immediately after sharpening or after a working period, influenced the surface quality. After the tool processed 600 m of beech material, the surface quality improved by 30%. The statistical analysis showed that the most important factor affecting the surface quality was the feed speed (implicitly fz, for constant n and number of cutters).

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the increased requirement of miniaturization structures on hard and brittle substrates, micro abrasive air jet turning technology has become a promising machining technology for manufacturing miniaturization structures. This paper presents an investigation on multi-pass radial-mode micro abrasive air jet turning of fused silica. The effect of machining parameters on the depth of cut and materials removal rate was analyzed. The waviness and striation formation mechanisms were studied. It was found that increasing the number of passes significantly increases the depth of cut and materials removal rate. When the surface speed is reduced, the depth of cut and materials removal rate significantly increases. The waviness may be attributed to the intersection and overlap of the adjoint jet footprint. The crossed striations have been found, which may lead to the elimination of the striation. A predictive model of the material removal rate was developed using the dimensional analysis method. The model was assessed and shown to be able to give adequate predictions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Basrah Researches (Sciences) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The friction behaviour of ZnO nanowires on natural graphite (NG) and highly oriented pyrolytic graphite (HOPG) substrates was tested in ambient conditions by use of optical microscopy based nanomanipulation. Nanowires on the step-free and waviness-free NG substrate exhibit a diameter-independent nominal frictional shear stress of 0.48 MPa, and this provides a benchmark for studying how the surface topography of graphite influences nanowire friction. Nanowires on the HOPG substrate present a significant diameter-dependent frictional shear stress, increasing from 0.25 to 2.78 MPa with the decrease of nanowire diameter from 485 to 142 nm. The waviness of HOPG has a limited effect on the nanowire friction, as a nanowire can fully conform to the substrate. The surface steps on the HOPG can significantly enhance the nanowire friction and lead to a much higher frictional shear stress than that on NG due to mechanical blocking and the presence of a Schwoebel barrier at step edges. The surface steps, however, can also generate small wedge-shaped gaps between a nanowire and substrate, and thus reduce the nanowire friction. With the decrease in nanowire diameter, the capacity for the nanowire to better conform to the substrate reduces the length of the wedge-shaped gaps, leading to the observed increase in nanowire friction. The results have improved our understanding of the unique friction behaviour of nanowires. Such an improved understanding is expected to benefit the design and operation of nanowire-friction-based devices, including bio-inspired fibrillar adhesives, soft grippers, rotary nanomotors, and triboelectric nanogenerators. [ABSTRACT FROM AUTHOR]

We studied the effect of the cutting speed during fine turning of the hardened KhVG steel on the force components and the cutting temperature, roughness and waviness of the machined surface. Finishing turning was carried out with cutters with the mechanical fastening of square tetrahedral plates (inserts) made of cubic boron nitride, manufactured in high-pressure machines from cBN and aluminum powders. The plate materials differed in phase composition, structure fineness, and physical and mechanical characteristics. With an increase in cutting speed from 0.8 to 5.5 m/s, the temperature of the cutter tip in the cutting zone increases nonlinearly from 650 to 1100°C, and the average values of the components and the resultant cutting force, the standard deviations of the components and the resultant cutting force, the amplitude of harmonic oscillations of the cutting force, the parameters of roughness and waviness of the machined surface decrease. It is advisable to use tools with a cubonite grain size of 2/1, 3/2, 7/5 and a cBN and AlN phase composition for the finishing turning of hardened KhVG steel. Tools with the grain size of the initial cBN powder 7/5 and the phase composition of the composite 87 wt % cBN + 13 wt % AlN demonstrated the best results. [ABSTRACT FROM AUTHOR]