Complex Surface Texture Research Articles

Mechanics of Capillary Forming of Aligned Carbon Nanotube Assemblies

Elastocapillary self-assembly is emerging as a versatile technique to manufacture three-dimensional (3D) microstructures and complex surface textures from arrangements of micro- and nanoscale filaments. Understanding the mechanics of capillary self-assembly is essential to engineering of properties such as shape-directed actuation, anisotropic wetting and adhesion, and mechanical energy transfer and dissipation. We study elastocapillary self-assembly (herein called "capillary forming") of carbon nanotube (CNT) microstructures, combining in situ optical imaging, micromechanical testing, and finite element modeling. By imaging, we identify sequential stages of liquid infiltration, evaporation, and solid shrinkage, whose kinetics relate to the size and shape of the CNT microstructure. We couple these observations with measurements of the orthotropic elastic moduli of CNT forests to understand how the dynamic of shrinkage of the vapor-liquid interface is coupled to the compression of the forest. We compare the kinetics of shrinkage to the rate of evporation from liquid droplets having the same size and geometry. Moreover, we show that the amount of shrinkage during evaporation is governed by the ability of the CNTs to slip against one another, which can be manipulated by the deposition of thin conformal coatings on the CNTs by atomic layer deposition (ALD). This insight is confirmed by finite element modeling of pairs of CNTs as corrugated beams in contact and highlights the coupled role of elasticity and friction in shrinkage and stability of nanoporous solids. Overall, this study shows that nanoscale porosity can be tailored via the filament density and adhesion at contact points, which is important to the development of lightweight multifunctional materials.

An advanced photogrammetric method to measure surface roughness: Application to volcanic terrains in the Piton de la Fournaise, Reunion Island

We present a rapid in situ photogrammetric method to characterize surface roughness by taking overlapping photographs of a scene. The method uses a single digital camera to create a high-resolution digital terrain model (pixel size of ~1.32mm) by means of a free open-source stereovision software. It is based on an auto-calibration process, which calculates the 3D geometry of the images, and an efficient multi-image correlation algorithm. The method is successfully applied to four different volcanic surfaces—namely, a′a lava flows, pahoehoe lava flows, slabby pahoehoe lava flows, and lapilli deposits. These surfaces were sampled in the Piton de la Fournaise volcano (Reunion Island) in October, 2011, and displayed various terrain roughnesses. Our in situ measurements allow deriving digital terrain models that reproduce the millimeter-scale height variations of the surfaces over about 12m2. Five parameters characterizing surface topography are derived along unidirectional profiles: the root-mean-square height (ξ), the correlation length (Lc), the ratio Zs=ξ2/Lc, the tortuosity index (τ), and the fractal dimension (D). Anisotropy in the surface roughness has been first investigated using 1-m-long profiles circularly arranged around a central point. The results show that Lc, Zs and D effectively catch preferential directions in the structure of bare surfaces. Secondly, we studied the variation of these parameters as a function of the profile length by drawing random profiles from 1 to 12m in length. We verified that ξ and Lc increase with the profile length and, therefore, are not appropriate to characterize surface roughness variation. We conclude that Zs and D are better suited to extract roughness information for multiple eruptive terrains with complex surface texture.

Aspects of Harmonic Structure, Voice Leading, and Aesthetic Function in György Ligeti's in Zart Fliessender Bewegung

This essay investigates the nature and origin of the harmonic structure and canonic voice leading that appears in the closing chorale-like coda of the third piece from György Ligeti's Three Pieces for Two Pianos, ‘In zart fliessender Bewegung’, from clues found in the sketches. Extrapolating from the coda, and using additional evidence from his sketches, this essay then traces the pitch–structural relationships between the coda and the melodic fragments that emerge from the complex surface texture in the opening of Bewegung. By briefly exploring structural parallels within Ligeti's mature works, this essay suggests how the compositional approach in Bewegung serves as a bridge between his middle and late styles. This essay concludes by considering how musical meaning in Bewegung is intertwined with the intertextual relationships that exist within Ligeti's oeuvre from at least the mid-1960s to the turn of the century.

Effects of seam and surface texture on tennis balls aerodynamics

Currently, serving becomes a dominant factor in tennis tournament as the ball travels faster and sometimes the returning player and spectators are unable to follow the track of the ball. As a result, the game becomes boring causing the spectator to lose passion for the game. The reduced speed of the ball can make the game more enjoyable. The understanding of aerodynamic behaviour of tennis balls is important in helping to design and develop a ball that can slow down the game. The complex surface texture of a tennis ball may affect its aerodynamic behaviour as well. As limited information on aerodynamic behaviour of contemporary tennis balls are available, a study was undertaken to investigate the effects of seam and surface texture of a range of commercially manufactured tennis balls. The drag coefficients were analysed and compared. The surface texture and seam orientation showed a noticeable variation in drag coefficients among these balls.

Dihexadecyl Phosphate-Assisted Synthesis of Unusual Calcium Carbonate Microspherules

The interesting finding is reported that unusual calcium carbonate (CaCO3) microspherules had been synthesized by simply mixing calcium chloride and ammonium bicarbonate with the assistance of dihexadecyl phosphate (DHP, an anionic lipid). The experimental results indicate that as-prepared CaCO3 microspherules with complex surface texture are predominantly vaterite with high stability. DHP plays a critical role in the formation of the well-defined CaCO3 microspherules.

Surface pore tension and adsorption characteristics of polluted sediment

Most natural sediment particles have numerous pores and a complex surface texture which facilitates their adsorption of contaminants. Particle surface structure, therefore, is an important instrumental factor in the transport of contaminants, especially in water environments. This paper reports on the results of adsorption-desorption experiments to analyze polluted sediment surface pore tension characteristics performed on samples from the bottom of Guanting Reservoir. In our analysis, the Frenkel-Halsey-Hill (FHH) equation is applied to calculate the fractal dimensions of particles to quantify the surface roughness and pore tension characteristics. The results show that the surface fractal dimensions of sediment particle surfaces normally measure from 2.6 to 2.85. The volume of pores smaller than 10 nm changes significantly after being contaminated with pollutants and the fractal dimension decreases because the pores adsorb the contaminants.

Crystallization of Calcium Carbonate Mineral with Hierarchical Structures in DMF Solution under Control of Poly(ethylene glycol)-b-poly(l-glutamic acid): Effects of Crystallization Temperature and Polymer Concentration

CaCO3 superstructures with complex forms and hierarchical surface textures were mineralized in the presence of peptide type block copolymer poly(ethylene glycol)-b-poly(l-glutamic acid) (PEG-b-pGlu) as a crystal growth modifier in dimethyl formamide (DMF) solution. Spindle-like CaCO3 crystals with a rather smooth surface and a size of 10 µm in length and a maximum diameter of 6 µm were mineralized at 24 ± 2 °C. Unique ellipsoid-like CaCO3 particles with many similar thorns distributed on the particle surface formed when the mineralization temperature was kept at 14 ± 2 °C. Complex column-like CaCO3 superstructures comprised of many tiny rods and irregular particles were observed at 4 ± 2 °C. In addition, when the reagent concentration is varied, the morphology of CaCO3 changes from a mixture of spherical and ellipsoidal structures to a kind of complex ellipsoidal superstructure whose surface is attached by many hierarchical tubular structures, and then to a complex columnar structure, when the concentrati...

Dental Microwear Texture Analysis of Varswater Bovids and Early Pliocene Paleoenvironments of Langebaanweg, Western Cape Province, South Africa

The extensive early Pliocene mammalian assemblages at Langebaanweg hold the potential to provide important information about paleoenvironments of the southwestern tip of Africa, an area that today consititutes the Fynbos Biome. We here add to a growing body of literature on the paleoenviornments of the site with an examination of dental microwear textures of bovids from the Varswater Formation. Microwear texture analysis is a new, automated and repeatable approach that measures whole surfaces in three dimensions without observer error. A study of extant ruminants indicates that grazers have more anisotropic microwear surface textures, whereas browsers have more complex microwear surface textures. Fossil bovids recovered from the Muishond Fontein Pelletal Phosphorite Member vary in their microwear textures, with some taxa falling within the extant browser range, some closer to extant grazers, and others in between. These results are consistent with scenarios suggesting mosaic habitats including fynbos vegetation, some (probably C3) grasses, and woodland elements when these fossils were accumulated.

Slicing of CAD models in ETL format

PurposeETL format is a newly proposed CAD format, which is both simple enough that CAD models in this format can be easily sliced, and capable of describing solids with arbitrarily complex surface details. This paper aims to provide a method for slicing CAD models in ETL format.Design/methodology/approachThe proposed slicing method is based on a method for slicing CAD models in colour STL format. Affine mapping method is used to calculate the colour of the intersection polygon of a voxel in the slicing result volume dataset, and a triangular facet that constitutes the geometry of the described object, when the facet has texture mapping definition.FindingsThe proposed slicing method is simple and robust. Implementations have demonstrated its feasibility.Originality/valueThe proposed slicing method is meaningful to preparing data for the rapid formation of models with complex surface details, including colour and textures.

Recent advances in colour rapid prototyping

Colour Rapid Prototyping (CRP) is a new field of rapid prototyping. An introduction to its recent advances is presented as follows. A new CAD format, the ETL format, has been proposed. It is both simple enough and capable of describing solids with arbitrarily complex surface textures. A new method for slicing CAD models in colour STL format and the ETL format has also been proposed. It is actually a voxelisation process. Other procedures for preparing colouring data for CRP have been presented as well, including thickening coloured regions in slicing result volume datasets and halftoning colour volume datasets. Finally comes an outlook on CRP.

Quantitative Evaluation for Influence of Complex Surface Texture on Fatigue Reliability from Meso-characteristics (3rd Report, Approximated Calculation of Stress Concentration of 2-Dimensional Complex Surface)

In this paper, the practical method to estimate the stress concentration factor (SCF) of two dimensional surface complex roughness is proposed. In the present method, the surface roughness is approximated with an infinite row of colinear notches which consists on “the local configuration” and “the average configuration”. The SCF values of the notches are calculated independently, and the SCF of the surface roughness is obtained by the superposition of each SCF values. The application limit of the present method is examined with the exact or Finite Element Method (FEM) solution. Moreover, the problem of colinear row of arbitrary notches which are satisfied with the application limit is solved by the present method and FEM. Comparing the present solution with FEM solution, the validity of the present method is examined.

Quantitative Evaluation for Influence of Complex Surface Texture on Fatigue Limit Reliability from Mesocharacteristics (2nd Report, Method to Predict Fatigue Limit Reliability and Its Application to Axisymmetric Surface Roughness)

In this paper, a method to predict the fatigue limit reliability of specimens with various surface roughness is proposed. First, the mechanical profile for fatigue limit is proposed. This is obtained from the ineffective crack length. Then the equivalent notch depth is proposed to treat a rough surface as a smooth surface with a notch. Next, a method to predict the fatigue limit reliability is discussed. As the surface roughness is expressed with the spectrum analysis, computational simulation is used to produce surface profiles. And stress analysis described in the first report is carried out for each specimen. Then a fatigue limit of an arbitrary metal specimen with an arbitrary small notch can be estimated. Moreover, rotating bending fatigue tests of 0.1% carbon steel with a complex surface are carried out. Then the experimental fatigue limit data is compared with the present estimated values. As results, the validity of the present meso-analysis is examined.

Quantitative Evaluation for Influence of Complex Surface Texture on Fatigue Limit Reliability from Mesocharacteristics. 1st Report. Stress Analysis of Infinite Plate with Complex Surface Profile.

The influence of surface roughness on fatigue limit is evaluated by a surface factor and a safe factor and they don't have the distinct physical meanings. To discuss a quantitative evaluation of surface roughness on fatigue limit reliability, the exact solution is given for a problem of an infinite plate with a complex profile under tension. The solution is obtained with the complex variable method. Some simple periodical notch problems are analyzed with the solution and also the method is shown to solve a problem of a complex profile.

Mars Global Surveyor observations of Martian fretted terrain

The Martian fretted terrain between latitudes 30° and 50°N and between 315° and 360°W has been reexamined in light of new Mars Orbiter Camera (MOC) and Mars Orbiter Laser Altimeter (MOLA) data from Mars Global Surveyor. Much of the terrain in the 30°–50° latitude belt in both hemispheres has a characteristic stippled or pitted texture at MOC (1.5 m) scale. The texture appears to result from partial removal of a formerly smooth, thin deposit as a result of sublimation and deflation. A complex history of deposition and exhumation is indicated by remnants of a former, thicker cover of layered deposits. In some hollows and on some slopes, particularly those facing the pole, are smooth textured deposits outlined by an outward facing escarpment. Throughout the study area are numerous escarpments with debris flows at their base. The escarpments typically have slopes in the 20°–30° range. At the base of the escarpment is commonly a deposit with striae oriented at right angles to the escarpment. Outside this deposit is the main debris apron with a surface that typically slopes 2°–3° and complex surface textures suggestive of compression, sublimation, and deflation. The presence of undeformed impact craters indicates that the debris flows are no longer forming. Fretted valleys contain lineated fill and are poorly graded. They likely form from fluvial valleys that were initially like those elsewhere on the planet but were subsequently widened and filled by the same mass‐wasting processes that formed the debris aprons. Slope reversals indicate that downvalley flow of the lineated fill is minor. The ubiquitous presence of breaks in slope formed by mass wasting and the complex surface textures that result from mass wasting, deflation, and sublimation decreases the recognizability of the shorelines formerly proposed for this area.

Radiosity including complex surfaces and geometric textures using solid irradiance and virtual surfaces

Procedural techniques for modeling complex surfaces (fractals, implicit surfaces, etc.) and geometric textures (texel maps, displacement maps, etc.) cannot be integrated efficiently into most current radiosity algorithms, since these techniques impose a geometry limited to patches (elementary surfaces). The usual way for including the above-mentioned complex features consists of applying a high rate sampling into small triangles. Often, the resulting enormous geometric complexity (millions of triangles) overloads the memory and computation capacity. In this paper, a radiosity approach for integrating efficiently all kinds of complex surfaces and geometric textures is presented. It is based on the use of virtual surfaces, solid irradiance and ray tracing techniques. The virtual surfaces simplify the overall geometry. They are used to calculate energy exchanges in the scene during the first pass of the radiosity simulation. The solid irradiance is used to estimate the incoming radiance on any point of the complex surface or geometric texture in order to compute the illumination of this point during the final rendering process (second pass). Finally, ray tracing techniques, adapted to the “direct” (e.g. without intermediate geometry) rendering of implicit, fractal or displacement mapped surfaces, allow us to avoid the high rate sampling into small triangles.

Computer Rigid Disk Surface Assessment With Laser Interferometry Using DDS

Laser interferometry in conjunction with the data dependent systems (DDS) methodology is first used in this paper to eliminate errors caused by instrumentation and software, and to recover the surface topography of a computer rigid disk used for illustration. The DDS methodology is then applied once more to decompose the surface height profile into a series of exponential and sinusoidal modes. The significant modes are related to the waviness and surface roughness resulting from different manufacturing processes. Surface reconstruction using only the important modes is presented. This provides a visual as well as mathematical description of the resultant effect of each process. The methodology can characterize very complex surface textures, reducing the reliance on complicated and expensive instruments needed for inspection, and replacing them with relatively inexpensive but reliable computation.

Disturbance of alveolar lining layer: effects on alveolar microstructure

To further study the influence of altered surface tensions on alveolar micromechanics, we analyzed the structure-function relationships in excised rabbit lungs filled with or rinsed by a fluorocarbon (approximately 15 mN/m) or by hexadecane (approximately 25 mN/m). The lungs were fixed and dehydrated by vascular perfusion, and the tissue samples were analyzed by light, transmission, and scanning electron microscopy. We made three observations. 1) Pressure-volume (P-V) loops hexadecane-filled lungs are shifted to the left and coincide with those of saline-filled lungs, indicating near-zero interfacial tension. In accordance, the alveolar microstructure and surface area of hexadecane-filled lungs resemble those of saline-filled lungs. 2) The P-V loops of fluorocarbon-filled lungs are not shifted to the left but coincide with those of fluorocarbon-rinsed lungs. Under both conditions, the alveolar microstructure is qualitatively identical and the alveolar surface areas are markedly reduced compared with normal air-filled lungs. These findings show that fluorocarbon-filled or fluorocarbon-rinsed lungs are subjected to similar interfacial tensions at the alveolar level. 3) Hexadecane-rinsed lungs show a pear-shaped P-V curve and a complex surface texture of peripheral air spaces. These results, together with in vitro observations, suggest a metamorphic interplay between lung surfactant and hexadecane in lining the surface and determining the surface tension. Evidently, the effects of foreign liquids introduced into the lung on the structure-function relationship cannot accurately be predicted from their in vitro surface tensions. This fact should be considered in the development of artificial surfactants.

Fractal Dimension Analysis of Mandibular Bones: Toward a Morphological Compatibility of Implants

In addition to biological and mechanical compatibilities for promising implant materials, a morphological compatibility is proposed by the authors. It has been reported by many investigators that implant surface with appropriate roughness and pore size exhibit better bone ingrowth activities. However, these parameters cannot characterize the complexity of surface textures. In the present study, dentulous and edentulous mandibular alveolar bones were utilized. Four segments from each mandible were subjected to the Fractal Dimension (DF) analysis. It was found that the dentulous mandible showed the DF of 1.81 +/- 0.03 while the edentulous mandible exhibited DF of 1.55 +/- 0.07, indicating that the former has more complex surface texture. It was also found that there could be a linear relationship between the surface roughness and the fractal dimension.

The use of a direct bonded microfilled composite resin veneer

This technique creates a direct bonded microfilled composite resin veneer that replicates the complex color distribution and surface texture of the natural tooth structure. Duplicating the complexity of natural tooth color can be repeated by recording the different layers of color used in their sequence of placement.

Morphology and chemistry of projectile residue in small experimental impact craters

Small‐scale impact craters (5‐7 mm in diameter) were produced with a light gas gun in high purity Au and Cu targets using soda lime glass (SL) and man‐made basalt glass (BG) as projectiles. Maximum impact velocity was 6.4 km/s resulting in peak pressures of approximately 120–150 GPa. Copious amounts of projectile melts are preserved as thin glass liners draping the entire crater cavity; some of this liner may be lost by spallation, however. SEM investigations reveal complex surface textures including multistage flow phenomena and distinct temporal deposition sequences of small droplets. Inasmuch as some of the melts were generated at peak pressures >120 GPa, these glasses represent the most severely shocked silicates recovered from laboratory experiments to date. Major element analyses reveal partial loss of alkalis; Na2O loss of 10–15% is observed, while K2O loss may be as high as 30–50%. Although the observed volatile loss in these projectile melts is significant, it still remains uncertain whether target melts produced on planetary surfaces are severely fractionated by selective volatilization processes.