Rounded Edges Research Articles

Preparation and characterization of smart hydrogels (magnetic field responsive)

Iron nanoparticles were prepared by using the co-precipitation process, and then used to fabricate magnetic field-responsive hydrogel films. The magnetic nanoparticles' structural, physical-chemical, morphological, and magnetic characteristics and the effect of hydrogel films' coating concentration were studied. The properties of the hydrogel film responsive to the magnetic field were investigated using Fourier analysis spectroscopy infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and a vibration sample magnetometer (VSM). The results indicated that all samples showed good inter-integration of the constituent materials and their functional groups. The hydrogel film samples which were polycrystalline, had broad diffraction peaks and showed constant particle size with nearly spherical particles with rounded edges. The SEM image of the magnetic nanoparticles with and without coating was established for the accumulation of numerous nanoparticles with a 17 nm mean diameter. In addition, the magnetic properties of the magnetic field-sensitive hydrogel films were evident and sufficient for drug delivery to the desired location.

Impact of tip curvature and edge rounding on the plasmonic properties of gold nanorods and their silver-coated counterparts.

Colloidal solutions of gold nanorods and silver-coated gold nanorods were prepared. The seeded growth synthesis protocols were improved by adding a flocculation purification step. The resulting populations of pure gold nanorods and Au@Ag core-shell cuboids were characterized by very low dispersion in size and shape. UV-vis-near-infrared absorption measurements were performed on several batches of well-calibrated nano-objects, supported by calculations based on the discrete dipole approximation, allowed to highlight the impact of various morphological features on the optical response. In addition to the well-known effect of the nanorod aspect ratio on the shift of the longitudinal surface plasmon resonance mode, special attention was paid to changing either the rounding of the nanorod end-caps or that of the edges of the coating silver shell. Nanorods and cuboids were modeled as superellipsoids. This approach enabled us to model precisely their complex shapes using just a few simple parameters and analyze the evolution of their extinction spectra as a function of the rounding of their tips and edges. Such nano-objects are widely used for various applications in fields such as biomedical, biosensing, or surface-enhanced Raman spectroscopy, thus making it crucial to precisely assess the impact of each morphological feature for optimizing their performance.

Preserving surface strain in nanocatalysts via morphology control.

Engineering strain critically affects the properties of materials and has extensive applications in semiconductors and quantum systems. However, the deployment of strain-engineered nanocatalysts faces challenges, in particular in maintaining highly strained nanocrystals under reaction conditions. Here, we introduce a morphology-dependent effect that stabilizes surface strain even under harsh reaction conditions. Using four-dimensional scanning transmission electron microscopy (4D-STEM), we found that cube-shaped core-shell Au@Pd nanoparticles with sharp-edged morphologies sustain coherent heteroepitaxial interfaces with larger critical thicknesses than morphologies with rounded edges. This configuration inhibits dislocation nucleation due to reduced shear stress at corners, as indicated by molecular dynamics simulations. A Suzuki-type cross-coupling reaction shows that our approach achieves a fourfold increase in activity over conventional nanocatalysts, owing to the enhanced stability of surface strain. These findings contribute to advancing the development of advanced nanocatalysts and indicate broader applications for strain engineering in various fields.

Redefinition of precision in finishing milling: Exploring the influence of tool margin and edge micro-radius on surface roughness

This article presents an analysis of microgeometry parameters, specifically the radius of cutting edge rounding, margin width, and rake angle influence on surface roughness in the milling of 7075 alloy. The study is underpinned by a set of 243 cutting tests conducted using 27 mills, each with a unique combination of geometry, feed, and radial infeed. Experimental mathematical models of the roughness parameters were developed. The findings reveal that while the influence of the cutting edge rounding radius on surface roughness is nonlinear and non-monotonic, the margin width has a monotonic effect and is the most significant factor impacting roughness.

Energy-size relationship and starch modification in planetary ball milling of quinoa

The effects of speed (250–450 rpm) and time (10–50 min) on milling energy (E), particle size distribution (PSD), crystallinity degree (CD), damaged starch (DS), microstructure, hydration and pasting properties of flours obtained in a planetary ball mill (PBM) were investigated. As increasing milling severity quinoa flours showed polydispersed PSD (peaks at 417, 40 and 2 μm) with a shift towards smaller size and greater dispersion (Span: 3.0–5.2) as well as particles with rounded edges and polished surfaces (SEM images). The relationship E − D50 were satisfactorily predicted by the Walker's equation. The hydration tests as function of temperature and milling conditions revealed a complex flour behavior due to differences in PSD, composition, and DS content. The increasing milling energy caused a decrease in peak viscosity (PV), trough viscosity (TV) and final viscosity (FV) of up to 36%, 29%, and 25%, respectively. Significant correlations between flour attributes were found (DS-CD, r = −0.83, p < 0.01; PV-D50, r = 0.92, p < 0.01; TV-D50, r = 0.94, p < 0.01; FV-D50, r = 0.90, p < 0.01) denoted the increase of starch degradation as milling severity rises. These results can be used to improve the manufacture and the selection criteria of quinoa flour with specific functional attributes.

Simple dynamical model that leads to sputter cone formation.

We introduce a model for sputter cone formation that includes only the angular dependence of the sputter yield and a fourth-order smoothing effect like surface diffusion. In one dimension, a sputter cone is a particular kind of shock wave that is known as an undercompressive shock. Simulations of our model show that a wide variety of initial conditions lead to the formation of sputter cones and that the opening angle of the cones does not depend on the detailed form of the initial condition. In two dimensions, a sputter cone is a higher-dimensional analog of an undercompressive shock. For two particularly simple choices of parameters, a sputter cone is a four-sided pyramid with rounded edges that is produced by the superposition of two orthogonal, one-dimensional undercompressive shocks.

Simulation and Algorithmic Optimization of the Cutting Process for the Green Machining of PM Green Compacts.

Powder metallurgy (PM) technology is extensively employed in the manufacturing sector, yet its processing presents numerous challenges. To alleviate these difficulties, green machining of PM green compacts has emerged as an effective approach. The aim of this research is to explore the deformation features of green compacts and assess the impact of various machining parameters on the force of cutting. The cutting variables for compacts of PM green were modeled, and the cutting process was analyzed using Abaqus (2022) software. Subsequently, the orthogonal test ANOVA method was utilized to evaluate the significance of each parameter for the cutting force. Optimization of the machining parameters was then achieved through a genetic algorithm for neural network optimization. The investigation revealed that PM green compacts, which are brittle, undergo a plastic deformation stage during cutting and deviate from the traditional model for brittle materials. The findings indicate that cutting thickness exerts the most substantial influence on the cutting force, whereas the speed of cutting, the tool rake angle, and the radius of the rounded edge exert minimal influence. The optimal parameter combination for the cutting of PM green compacts was determined via a genetic algorithm for neural network optimization, yielding a cutting force of 174.998 N at a cutting thickness of 0.15 mm, a cutting speed of 20 m/min, a tool rake angle of 10°, and a radius of the rounded edge of 25 μm, with a discrepancy of 4.05% from the actual measurement.

Viscous crack healing in soda–lime–magnesium–silicate–ZrO2 glass matrix composites

AbstractThe present study investigates the influence of the crystal volume content on viscous crack healing in glass ceramic glass sealants. To ensure constant microstructure during healing, soda–lime–magnesium silicate glass matrix composites with varied volume fractions of ZrO2 filler particles were used. Crack healing was studied on radial cracks induced by Vickers indentation, which were stepwise annealed to monitor the healing progress by confocal laser scanning microscopy. Confirming previous studies, healing of radial cracks in pure glass was found delayed by global flow phenomena like crack widening and crack edge and tip rounding to minimize the sample surface. With increasing ZrO2 filler content, these global flow phenomena were progressively inhibited whereas local flow phenomena like sharp crack tip healing could still occur. As a result, crack healing was even accelerated by filler particles up to a maximum filler content of 17 vol% whereas crack healing was fully suppressed only at 33 vol% filler content.

Effect of Countersample Coatings on the Friction Behaviour of DC01 Steel Sheets in Bending-under-Tension Friction Tests.

The aim of this article is to provide an analysis of the influence of the type of hard anti-wear coatings on the friction behaviour of DC01 deep-drawing steel sheets. DC01 steel sheets exhibit high formability, and they are widely used in sheet metal forming operations. The tribological properties of the tool surface, especially the coating used, determine the friction conditions in sheet metal forming. In order to carry out the research, this study developed and manufactured a special bending-under-tension (BUT) friction tribometer that models the friction phenomenon on the rounded edges of tools in the deep-drawing process. The rationale for building the tribotester was that there are no commercial tribotesters available that can be used to model the phenomenon of friction on the rounded edges of tools in sheet forming processes. The influence of the type of coating and sheet deformation on the coefficient of friction (CoF) and the change in the topography of the sheet surface were analysed. Countersamples with surfaces prepared using titanium + nitrogen ion implantation, nitrogen ion implantation and electron beam remelting were tested. The tests were carried out in conditions of dry friction and lubrication with oils with different kinematic viscosities. Under dry friction conditions, a clear increase in the CoF value, with the elongation of the samples for all analysed types of countersamples, was observed. Under lubricated conditions, the uncoated countersample showed the most favourable friction conditions. Furthermore, oil with a lower viscosity provided more favourable conditions for reducing the coefficient of friction. Within the entire range of sample elongation, the most favourable conditions for reducing the CoF were provided by uncoated samples and lubrication with S100+ oil. During the friction process, the average roughness decreased as a result of flattening the phenomenon. Under dry friction conditions, the value of the Sa parameter during the BUT test decreased by 20.3-30.2%, depending on the type of countersample. As a result of the friction process, the kurtosis and skewness increased and decreased, respectively, compared to as-received sheet metal.

Arc-enhanced glow discharge ion etching of WC-Co cemented carbide for improved PVD thin film adhesion and asymmetric cutting edge preparation of micro milling tools

Wear-resistant thin films on cutting tools require effective ion etching to enhance adhesion and thus extended tool service life. Arc enhanced glow discharge (AEGD) ion etching, characterized by high ionization degrees and high etch rates, was applied to ultrafine-grained WC-Co cemented carbide, commonly used for micromilling cutters. The effect of AEGD ion etching on the surface integrity of WC-Co and the resulting adhesion behavior of a TiAlSiN thin film was investigated by varying the etching time in comparison with conventional glow discharge (GD) ion etching. In addition, the impact of intensive etching on the cutting edge geometry of micro end cutters and, in turn, on the cutting performance in micromilling of hardened and annealed high-speed steel was evaluated.AEGD achieves remarkable etch rates of 12 nm/min at extended etching times, which are 100 times greater than conventional glow discharge (GD) ion etching. Prolonged AEGD ion etching for ≥30 min removes entire near-surface WC grains and exposes carbides beneath, resulting in increased surface roughness. After the etching process, polished WC-Co substrates exhibit a slight reduction in residual compressive stresses, which steadily decrease with increasing AEGD ion etching time. Furthermore, a TiAlSiN thin film demonstrates high adhesion on AEGD-etched surfaces compared to GD ion etching. Even a brief 5 min AEGD ion etching ensures the highest adhesion class according to the Rockwell C indentation test. Moreover, the intensive material removal results in significant changes in cutting edge geometry of micro end cutters, yielding substantial cutting edge rounding and an asymmetrical shape with form-factors Κ ≥ 2. In cutting tests, the resulting cutting edge geometries effectively reduce the wear formation and the associated wear-related increase in process forces during micromilling hardened and tempered powder metallurgical high-speed steel. In summary, AEGD ion etching emerges as a highly effective method for both enhancing thin film adhesion and preparing adapted asymmetrical cutting edge geometries for micromilling tools.

Enhancing photovoltaic applications through precipitating agents in ITO/CIS/CeO2/Al heterojunction solar cell

In this groundbreaking study, we successfully synthesized both cerium oxide and copper indium sulphate nanoparticles via co-precipitation method and the same is spray coated on ITO substrate by Jet Nebulizer Spray Pyrolysis (JNSP) technique. A comprehensive characterization of the structural, morphological and Photo-diode properties was conducted using a range of advanced techniques. X-ray diffraction revealed a superior mono-crystalline cubic fluorite structure with a preferred orientation along the (111) plane, indicating exceptional crystal quality. Scanning electron microscopy and transmission electron microscopy images showed the formation of disk-shaped particles with sharp rounded edges, averaging ∼ 5 nm in size. Fourier transform infrared spectroscopy identified the phonon band envelope of the metal oxide (CeO2) network at 848 cm−1 while photoluminescence spectroscopy revealed blue and blue-green emission in the visible spectrum. Thermogravimetric-differential thermal analysis exhibited a total weight loss of 19.52 % with four distinct exothermic and endothermic peaks. X-ray photoelectron spectroscopy confirmed the presence of Ce and O elements, with a minor amount of carbon absorbed from the atmosphere and revealed the dominant occurrence of Ce4+ and minority occurrence of Ce3+. The maximum power conversion efficiency of 0.23 % was achieved for samples prepared using NH3 precipitant making them highly suitable for photovoltaic applications. This work paves the way for future research in optimizing cerium oxide nanoparticles for high-performance photovoltaic devices potentially leading to breakthroughs in renewable energy harvesting.

Enhancing Pump as Turbine (PAT) performances: A numerical investigation into the impact of impeller leading edge rounding

Pump As Turbine (PAT) utility represents a major advance in the field of hydraulic engineering. This work aims to improve the PAT performance characteristics. The sharp impeller leading edge (original impeller) was revealed by flow analysis as exhibiting negative effects on the PAT performances due to flow separation and flow misalignment. The performances of rounded and original impeller leading edge were studied by Computational Fluid Dynamic (CFD) method carried out on ANSYS CFX. Although impeller leading edge rounding has notably improved the performances in off design conditions, the difference of efficiency between the both impeller types was decreasing when increasing the discharge. The hydraulic head generated by the rounded impeller leading edge was also slightly higher at part load conditions, but when increasing the discharge, the difference between the both heads became negligible. It appeared from numerical simulations that the impeller leading edge rounding allows to decrease the hydraulic losses of the individual sub-domains except the outlet pipe. For the seek of a comprehensive analysis, the significant losses were computed for the two impeller geometries. It was observed that the shock losses and swirling losses of the rounded impeller leading edge were lower at part load conditions, but when increasing the discharge, the both losses were lower for the original impeller geometry. The rounded impeller leading edge exhibited as well lower wall frictional losses for the entire operating range of discharge.

Сравнительный прочностной анализ алмазных сегментов канатных камнерезных станков

The paper discusses the different shapes of diamond segments for stone cutting machines. The purpose of this research is to find ways to improve the abrasion resistance of the diamond segments, reduce the vibration load and increase the cutting efficiency. The operating conditions of stone-cutting machines are analysed, as well as the ways of increasing the efficiency of diamond segments by changing their shape. A calculation of the loads arising during operation of the diamond segments is made, and the results are verified using an experimental setup. The initial shape is analysed and the stresses that exceed the material parameters are found. In order to reduce the stresses, a diamond segment with rounded edges is simulated. Segments with bevelled edges and conical shape are also considered. Based on the experimental results, it is found that one of the promising shapes is that with rounded edges.

Fluid resonance in narrow gaps formed by three-box system with sharp and round edge profiles under irregular wave actions

Fluid resonance within narrow gaps in multiple-box systems with sharp and round edge profiles under irregular wave actions are investigated by using a viscous fluid flow solver based on OpenFOAM® package. In difference to the two-peak behavior under regular wave actions, the variation of free surface amplitudes in narrow gaps with incident spectral peak frequencies show the single-peak behavior, including the sharp and round edge profiles. Spectral analysis indicates that the wave spectrums of fluid oscillations in narrow gaps mainly around the first- and/or second-order resonant frequencies. The second-order fluid resonance is easier to be aroused for round edge profiles than that for sharp edge profiles. Furthermore, the statistical and histogram results indicate the significant periods are always around the resonant frequencies; while the corresponding standard deviations approach to cover the region between two resonant frequencies. The above results confirm that the wave responses in narrow gaps mainly oscillate with two resonant frequencies under irregular wave actions.

Abstract Shape Aesthetics: Contour, Complexity, Motion, and Individual Variability

Abstract The aesthetics of abstract shapes — shapes devoid of meaning or familiarity — offer an intriguing subject for study, as it can offer insights into how we perceive and appreciate visual stimuli, shedding light on the underlying mechanisms of visual cognition and the nature of artistic experience. This research investigates the impact of contour type (angular versus rounded edges) and complexity (number of vertices) on aesthetic preferences, including their potential interaction. Additionally, we explored the influence of movement as an aesthetic variable, given its potential to enhance complexity, though the relationship between movement and complexity remains unexplored. Our findings indicate that both contour type and complexity significantly influence preferences, with shapes featuring curved contours and fewer vertices being favoured. This highlights the aesthetic appeal of curvature and simplicity. Contrary to expectations, movement did not have a noticeable effect on aesthetic judgements. While no overall interaction between contour type and complexity was found, this lack of interaction was obscured by significant individual differences. Specifically, within individuals, strong interactions between contour type and complexity were observed. It appears that these individual differences are due more to the varying emphasis (dominance) placed on each variable rather than a difference in the preference for specific characteristics. Future research should further analyse these individual differences to understand the nuanced dynamics of aesthetic preferences.

Numerical investigation of elliptical trailing edge on cascade loss of transonic turbine airfoils

Abstract The shape and thickness of the trailing edge are important factors in the supersonic loss in transonic cascades. To investigate the influence of trailing edge shape, a prismatic turbine cascade and a three-dimensional cascade with an elliptic trailing edge were analyzed with numerical simulation by changing different elliptic axis ratios ER. It was indicated that the shock wave and its mixing with the wake were the important sources of loss in the transonic prismatic cascade. With the increase of exit Mach number, shock waves are generated rapidly and migrate downstream, and the shock loss and the total loss of the prismatic cascade are both accrescent. Increasing the elliptical axis ratio could weaken shock waves and delay shock waves. In the loss state region 3, the cascade loss of the ER3 blade is reduced by 8% compared with the round trailing edge cascade. As the elliptical axis ratio of the three-dimensional cascade is increasing, the profile loss and secondary loss are reduced. However, an excessive elliptical axis ratio could lead to an increase in tip leakage loss. Within the range of ER values from 0 to 3, the total loss of the transonic three-dimensional cascade reached minimization when ER was 3.0.

Emendation of Rhodomonas marina (Cryptophyceae): insights from morphology, molecular phylogeny and water-soluble pigment in an Arctic isolate

Rhodomonas (Cryptophyceae) and species assigned to this genus have undergone numerous taxonomic revisions. This also applies to R. marina studied here as it was originally assigned as a species of Cryptomonas and later considered a variation of R. baltica, the type species. Despite being described more than 130 years ago, R. marina still lacks a comprehensive characterization. Light and electron microscopy were employed to delineate a strain from western Greenland. The living cells were 18 μm long and 9 μm wide, elliptical in shape with a pointed to rounded posterior and truncated anterior in lateral view. Two sub-equal flagella emerged from a vestibulum, where also a furrow extended. In transmission electron microscopy, the furrow was associated with a tubular gullet and the pyrenoid embedded in a deeply lobed chloroplast. The chloroplast contained DNA in perforations and was surrounded by starch grains. A tubular nucleomorph was enclosed within the pyrenoid matrix. In scanning electron microscopy, the inner periplast consisted of rectangular plates with rounded edges and posteriorly these were replaced by a sheet-like structure. The water-soluble pigment was Crypto-Phycoerythrin type I (Cr-PE 545). A phylogenetic inference based on SSU rDNA confirmed the identity of strain S18 as a species of Rhodomonas as it clustered with congeners but also Rhinomonas, Storeatula, and Pyrenomonas. These genera formed a monophyletic clade separated from a diverse assemblage of other cryptophyte genera. To further explore the phylogeny of R. marina a concatenated phylogenetic analysis based on the SSU rDNA-ITS1-5.8S rDNA-ITS2- LSU rDNA region was performed but included only closely related species. The secondary structure of nuclear internal transcribed spacer 2 was predicted and compared to similar structures in related species. Using morphological and molecular signatures as diagnostic features the description of R. marina was emended.

Directional sensitivity of bone conduction stimulation on the otic capsule in a finite element model of the human temporal bone

Sound transmission to the human inner ear by bone conduction pathway with an implant attached to the otic capsule is a specific case where the cochlear response depends on the direction of the stimulating force. A finite element model of the temporal bone with the inner ear, no middle and outer ear structures, and an immobilized stapes footplate was used to assess the directional sensitivity of the cochlea. A concentrated mass represented the bone conduction implant. The harmonic analysis included seventeen frequencies within the hearing range and a full range of excitation directions. Two assessment criteria included: (1) bone vibrations of the round window edge in the direction perpendicular to its surface and (2) the fluid volume displacement of the round window membrane. The direction of maximum bone vibration at the round window edge was perpendicular to the round window. The maximum fluid volume displacement direction was nearly perpendicular to the modiolus axis, almost tangent to the stapes footplate, and inclined slightly to the round window. The direction perpendicular to the stapes footplate resulted in small cochlear responses for both criteria. A key factor responsible for directional sensitivity was the small distance of the excitation point from the cochlea.

Experimental investigations on the effect of upstream-edge rounding on the BARC configuration

We experimentally investigate the influence of upstream-edge roundness on the flow around a 5:1 rectangular cylinder. We examine various values of edge curvature radius, ranging from nearly sharp edges to r/D=0.1104 at Reynolds number Re=40000, based on the freestream velocity and the crossflow dimension of the cylinder. Additionally, we explore the combined effects of edge roundness and (i) Reynolds number (Re=20000−80000) and (ii) angle of attack (|α|≤2deg). For all examined Re and α, limited sensitivity to upstream-edge rounding is observed up to r/D=0.0360, with results close to those obtained for nominally sharp edges. For r/D≥0.0781, and fixed Re and α=0deg, a noticeable decrease in the size of the mean recirculation region alongside the rectangular cylinder, lr, is observed with increasing r/D. For r/D≥0.0781, the flow features are also sensitive to Re, with a reduction in the length of the mean recirculation with increasing Re. The reduction of lr with increasing r/D and Re is due to the detached shear layer becoming more tilted towards the cylinder. Finally, for r/D≥0.0781, the effect of α, that is the increase of lr on the leeward side surface and the opposite on the windward side, is more important than for small r/D values.

Neuro-ophthalmic Tests for Assessment of Vision Before and After Phacoemulsification in Cataractous Dogs

Background: The aim of current study was to assess pre and post-operative vision status through neuro-ophthalmic examination of 24 canine eyes after phacoemulsification with implantation of different acrylic intra ocular lenses. Methods: The study was conducted on 24 canine eyes. Preoperatively, detailed neuro-ophthalmic tests viz. Menace response, Pupillary light reflex (PLR), Obstacle Course and Moving object (cotton ball) were conducted for assessment of vision due to cataract and to exclude other ocular pathologies. Dogs were divided in four groups with 6 eyes in each group and subjected to phacoemulsification procedure for removal of cataractous lens and implanted with square edge or round edge, hydrophilic or hydrophobic intra ocular lenses (IOL). Post operatively, aforementioned neuro-ophthalmic tests were conducted on 3, 7 and 15 days and scores were given and comparatively analysed for vision acuity. Result: Preoperatively, neuro-opthalmic tests indicated poor and absent vision in eyes affected with various stages of cataract. Post operatively, the visual outcome in dogs of all treatment groups were assessed from the scores obtained in various neuro-ophthalmic tests. Neuro-ophthalmic evaluation revealed restoration of vision in 50% dogs in group I, II, IV and in 66.66% dogs of group III on day 15 after phacoemulsification and intraocular lens (IOL) implantation. It was concluded that neuro-ophthalmic tests are useful and mandatory protocols for pre and post-operative vision assessment in dogs with cataract.