scholarly journals Surface roughness rather than surface chemistry essentially affects insect adhesion

2016 ◽  
Vol 7 ◽  
pp. 1471-1479 ◽  
Author(s):  
Matt W England ◽  
Tomoya Sato ◽  
Makoto Yagihashi ◽  
Atsushi Hozumi ◽  
Stanislav N Gorb ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Chemistry ◽  
Coccinella Septempunctata ◽  
Traction Force ◽  
Dominant Factor ◽  
Chemical Compositions ◽  
Specific Chemical ◽  
Chemical Surface ◽  
Ladybird Beetles ◽  
Attachment Ability

The attachment ability of ladybird beetles Coccinella septempunctata was systematically investigated on eight types of surface, each with different chemical and topographical properties. The results of traction force tests clearly demonstrated that chemical surface properties, such as static/dynamic de-wettability of water and oil caused by specific chemical compositions, had no significant effect on the attachment of the beetles. Surface roughness was found to be the dominant factor, strongly affecting the attachment ability of the beetles.

scholarly journals The effect of surface anisotropy in the slippery zone of Nepenthes alata pitchers on beetle attachment

2011 ◽  
Vol 2 ◽  
pp. 302-310 ◽  
Author(s):  
Elena V Gorb ◽  
Stanislav N Gorb
Keyword(s):  
Coccinella Septempunctata ◽  
Carnivorous Plant ◽  
Surface Anisotropy ◽  
Anisotropic Properties ◽  
Surface Samples ◽  
Ladybird Beetles ◽  
Attachment Ability ◽  
Wax Crystals ◽  
Insect Attachment ◽  
Effect Of Surface

The slippery zone in pitchers of the carnivorous plant Nepenthes alata bears scattered prominent lunate cells and displays continuous epicuticular crystalline wax coverage. The aim of this study was to examine the influence of the surface anisotropy, caused by the shape of lunate cells, on insect attachment ability. Traction tests with ladybird beetles Coccinella septempunctata were performed in two types of experiments, where surface samples of (1) intact pitchers, (2) chemically de-waxed pitchers, and (3) their polymer replicas were placed horizontally. Beetle traction forces were measured when they walked on test surfaces in either an upward (towards the peristome) or downward (towards the pitcher bottom) direction, corresponding to the upright or inverted positions of the pitcher. On intact pitcher surfaces covered with both lunate cells and wax crystals, experiments showed significantly higher forces in the direction towards the pitcher bottom. To distinguish between the contributions, from claw interlocking and pad adhesion, to insect attachment on the pitcher surfaces, intact versus claw-ablated beetles were used in the second type of experiment. On both de-waxed plant samples and their replicas, intact insects generated much higher forces in the downward direction compared to the upward one, whereas clawless insects did not. These results led to the conclusion that, (i) due to the particular shape of lunate cells, the pitcher surface has anisotropic properties in terms of insect attachment, and (ii) claws were mainly responsible for attachment enhancement in the downward pitcher direction, since, in this direction, they could interlock with overhanging edges of lunate cells.

scholarly journals Influence of ambient humidity on the attachment ability of ladybird beetles (Coccinella septempunctata)

2016 ◽  
Vol 7 ◽  
pp. 1322-1329 ◽  
Author(s):  
Lars Heepe ◽  
Jonas O Wolff ◽  
Stanislav N Gorb
Keyword(s):  
Environmental Conditions ◽  
Coccinella Septempunctata ◽  
Dry Adhesive ◽  
Ladybird Beetle ◽  
Ambient Humidity ◽  
Ladybird Beetles ◽  
Significant Difference ◽  
Attachment Ability ◽  
Adhesive Fluid

Many insects possess adhesive foot pads, which enable them to scale smooth vertical surfaces. The function of these organs may be highly affected by environmental conditions. Ladybird beetles (Coccinellidae) possess dense tarsal soles of tenent setae, supplemented with an adhesive fluid. We studied the attachment ability of the seven-spotted ladybird beetle (Coccinella septempunctata) at different humidities by horizontal traction experiments. We found that both low (15%) and high (99%) relative humidities lead to a decrease of attachment ability. The significantly highest attachment forces were revealed at 60% humidity. This relationship was found both in female and male beetles, despite of a deviating structure of adhesive setae and a significant difference in forces between sexes. These findings demonstrate that not only dry adhesive setae are affected by ambient humidity, but also setae that stick due to the capillarity of an oily secretion.

scholarly journals Insect attachment on crystalline bioinspired wax surfaces formed by alkanes of varying chain lengths

2014 ◽  
Vol 5 ◽  
pp. 1031-1041 ◽  
Author(s):  
Elena Gorb ◽  
Sandro Böhm ◽  
Nadine Jacky ◽  
Louis-Philippe Maier ◽  
Kirstin Dening ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Coccinella Septempunctata ◽  
Fold Reduction ◽  
Adhesive Pads ◽  
Highly Hydrophobic ◽  
Chain Lengths ◽  
Attachment Ability ◽  
Insect Attachment

The impeding effect of plant surfaces covered with three-dimensional wax on attachment and locomotion of insects has been shown previously in numerous experimental studies. The aim of this study was to examine the effect of different parameters of crystalline wax coverage on insect attachment. We performed traction experiments with the beetle Coccinella septempunctata and pull-off force measurements with artificial adhesive systems (tacky polydimethylsiloxane semi-spheres) on bioinspired wax surfaces formed by four alkanes of varying chain lengths (C36H74, C40H82, C44H90, and C50H102). All these highly hydrophobic coatings were composed of crystals having similar morphologies but differing in size and distribution/density, and exhibited different surface roughness. The crystal size (length and thickness) decreased with an increase of the chain length of the alkanes that formed these surfaces, whereas the density of the wax coverage, as well as the surface roughness, showed an opposite relationship. Traction tests demonstrated a significant, up to 30 fold, reduction of insect attachment forces on the wax surfaces when compared with the reference glass sample. Attachment of the beetles to the wax substrates probably relied solely on the performance of adhesive pads. We found no influence of the wax coatings on the subsequent attachment ability of beetles. The obtained data are explained by the reduction of the real contact between the setal tips of the insect adhesive pads and the wax surfaces due to the micro- and nanoscopic roughness introduced by wax crystals. Experiments with polydimethylsiloxane semi-spheres showed much higher forces on wax samples when compared to insect attachment forces measured on these surfaces. We explain these results by the differences in material properties between polydimethylsiloxane probes and tenent setae of C. septempunctata beetles. Among wax surfaces, force experiments showed stronger insect attachment and higher pull-off forces of polydimethylsiloxane probes on wax surfaces having a higher density of wax coverage, created by smaller crystals.

scholarly journals The Effect of Two-Stage Acid Treatment on Surface Behavior and Improvement of Bioactivity of Nitinol Alloy

2020 ◽  
Vol 11 (3) ◽  
pp. 10690-10702
Keyword(s):  
Surface Roughness ◽  
Chemical Modification ◽  
Surface Chemistry ◽  
Healing Process ◽  
In Vitro Study ◽  
Surface Chemical ◽  
Two Stage ◽  
Nitinol Alloy ◽  
Surface Chemical Modification

Surface properties, including morphology, submicron morphology, and surface chemistry, are essential factors that affect the quality and manner of biological responses at the site of tissue contact with the implant, affecting the bone healing process. In this in vitro study, morphology and biocompatibility of nitinol (NiTi) memory alloy surfaces mechanically polished and modified with a chemical solution consisting of three types of acid (HCl-HF-H3PO4) and then chemical operations in solution (HNO3 and HCl) with a Volumetric scale of 1:1 and examined at ambient temperature. 75 samples were used for surface chemical modification, biological evaluations, and surface roughness, and also 9 samples as control. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and nitinol alloy (NiTi) surface roughness measurements were performed to analyze the surfaces. Besides, MG-63 cells were cultured on different nitinol alloy levels to evaluate adhesion and cell growth and proliferation. Data were analyzed using t-test and one-way analysis of variance. The results show that the chemical surface modification operation with two-stage acid solution had a higher roughness compared to the unmodified surfaces and the surface chemical modification operation with the acidic solution with an only solution consisting of (HCl-HF-H3PO4). Cell culture evaluations also showed that the two-stage modified nitinol levels showed significant cell adhesion and significant growth and proliferation compared to the tertiary acid-modified and unmodified levels. The surface chemical modification method for nitinol alloy can change the surface chemistry and change the surface morphology and create sub-micron scale roughness. This can increase the connectivity of the implant tissue and reduce the toxic effect of nickel.

scholarly journals Mechanical properties of NiTi and CuNiTi wires used in orthodontic treatment. Part 2: Microscopic surface appraisal and metallurgical characteristics

2014 ◽  
Vol 19 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Marco Abdo Gravina ◽  
Cristiane Canavarro ◽  
Carlos Nelson Elias ◽  
Maria das Graças Afonso Miranda Chaves ◽  
Ione Helena Vieira Portella Brunharo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Test Methods ◽  
Chemical Compositions ◽  
Wire Surface ◽  
Morphologic Characteristics ◽  
Fracture Region ◽  
Traction Test ◽  
Niti Wires ◽  
Electronic Microscope

OBJECTIVE: This research aimed at comparing the qualitative chemical compositions and the surface morphology of fracture regions of eight types of Nickel (Ni) Titanium (Ti) conventional wires, superelastic and heat-activated (GAC, TP, Ormco, Masel, Morelli and Unitek), to the wires with addition of copper (CuNiTi 27oC and 35oC, Ormco) after traction test. METHODS: The analyses were performed in a scanning electronic microscope (JEOL, model JSM-5800 LV) with EDS system of microanalysis (energy dispersive spectroscopy). RESULTS : The results showed that NiTi wires presented Ni and Ti as the main elements of the alloy with minimum differences in their composition. The CuNiTi wires, however, presented Ni and Ti with a significant percentage of copper (Cu). As for surface morphology, the wires that presented the lowest wire-surface roughness were the superelastic ones by Masel and Morelli, while those that presented the greatest wire-surface roughness were the CuNiTi 27oC and 35oC ones by Ormco, due to presence of microcavity formed as a result of pulling out some particles, possibly of NiTi. 4 The fracture surfaces presented characteristics of ductile fracture, with presence of microcavities. The superelastic wires by GAC and the CuNiTi 27oC and the heat-activated ones by Unitek presented the smallest microcavities and the lowest wire-surface roughness with regard to fracture, while the CuNiTi 35oC wires presented inadequate wire-surface roughness in the fracture region. CONCLUSION: CuNiTi 35oC wires did not present better morphologic characteristics in comparison to the other wires with regard to surfaces and fracture region.

Surface Modification of a-C:H(N) Thin Films by Plasma Treatment

2005 ◽  
Vol 11 (S03) ◽  
pp. 162-165 ◽  
Author(s):  
L. von Mühlen ◽  
R. A. Simao ◽  
C. A. Achete
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Optical Properties ◽  
Surface Modification ◽  
Surface Chemistry ◽  
Plasma Treatment ◽  
Surface Properties ◽  
Functional Groups ◽  
Material Properties ◽  
Modify Surface

Surface chemistry and topography of materials are generally preponderant factors in a series of material properties, such as adhesion, wettability, friction and optical properties [1]. Wettability of films, for example, can be altered significantly by modifying its surface roughness and also by incorporating functional groups. Plasma treatment is a powerful and versatile way to modify surface properties of amorphous nitrogen-incorporated carbon thin films (a-C:H(N)) and obtain materials with improved properties, once it is possible to modify the surfaces in a controlled way by specific settings of plasma conditions. [2 - 4]

Growth of Silicon Films Onto Fluororesin Surface by ArF Excimer Laser

1993 ◽  
Vol 334 ◽  
Author(s):  
T. Miyokawa ◽  
M. Okoshi ◽  
K. Toyoda ◽  
M. Murahara
Keyword(s):  
Surface Roughness ◽  
Surface Modification ◽  
Excimer Laser ◽  
High Density ◽  
Silicon Films ◽  
Chemical Compositions ◽  
Xps Analysis ◽  
Modification Process ◽  
Arf Excimer Laser ◽  
Mixed Gases

AbstractSilicon films were deposited on a fluororesin surface. The process was divided into two steps: surface modification process and silicon CVD onto the modified parts. In the modification process, SiH4 and B(CH3)3 mixed gases were used with ArF excimer laser. Fluorine atoms of the surface were pulled out by boron atoms which were photo—dissociated from B(CH3)3 and were replaced with silicon atoms released from SiH4. In the CVD process, SiH4 gas was used with high—density excited ArF excimer laser. Silicon films were deposited onto the nuclei by photodecomposition of SiH4.Chemical compositions of the modified layers and the deposited parts were inspected by XPS analysis. 1000 Å thickness of the deposited silicon films was confirmed by the surface roughness interference–meter.

scholarly journals Effects of 1450-ppm Fluoride-containing Toothpastes Associated with Boosters on the Enamel Remineralization and Surface Roughness after Cariogenic Challenge

2020 ◽  
Vol 14 (01) ◽  
pp. 161-170
Author(s):  
Pedro Luiz Santos Tomaz ◽  
Letícia Almeida de Sousa ◽  
Kayanne Freire de Aguiar ◽  
Thales de Sá Oliveira ◽  
Marcelo Henrick Maia Matochek ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Longitudinal Section ◽  
Enamel Surface ◽  
Physical Parameters ◽  
Specific Chemical ◽  
Caries Lesion ◽  
Ph Cycling

Abstract Objectives This in vitro study investigated the remineralization potential of 1450 ppm, fluoride-containing toothpastes containing different active remineralization agents after cariogenic challenge with pH cycling. The enamel surface roughness after brushing and the chemical and physical characteristics of the toothpastes tested were also analyzed. Materials and Methods Fifty-six bovine enamel blocks were obtained (4 × 4 × 6 mm) and divided into three thirds: intact (untreated), demineralized (artificial caries lesion), and treated (caries lesion, pH cycling, and brushing with dentifrices). Seven commercially available fluoride toothpastes (1450 ppm F): three with anti-erosion claims (Candida Professional [CPP], Colgate Total 12 Daily Repair [CDR], Regenerate Enamel Science [RES]); three with desensitizing claims (Bianco Pro Clinical [BPP], Elmex Sensitive [ESS], and Regenerador Diário DentalClean [RDC]); and one standard regular-fluoride toothpaste Colgate Total 12 (CTT) were selected. During pH cycling (demineralization 6 h/remineralization 18 h) for 7 days, the treated third was brushed with the different dentifrices for 10 minutes in a brushing machine before immersion in a remineralizing solution. The Knoop hardness (25 g, 10 second of the surface, and longitudinal section were then evaluated at eight depths (10 to 330 μm). Mean and percentage of surface hardness recovery (% SHR) were calculated. Surface enamel roughness (Ra) was also evaluated. The pH, %weight of particles, zeta potential, and polydispersity index of toothpaste slurries were also evaluated. Statistical Analysis Data were statistically analyzed (ANOVA/Tukey, 5%). Results The %SHR of CPP was significantly lower than the others (p < 0.05). The enamel subsurface was more effectively remineralized when treated with BPP, ESS, and RDC. The surface roughness was higher when the demineralized third was treated with CTT, RDC, and RES and after the cariogenic challenge (p < 0.05). For some of the products tested, there was no relationship between surface remineralization and subsurface remineralization. Although toothpastes CPP and RDC present the lowest %SHR means, both products effectively remineralize within the subsurface carious lesion. Regression analysis demonstrated no strong correlations of the enamel surface roughness with the chemical and physical parameters. Conclusions Most but not all the fluoride toothpastes were able to remineralize the enamel surface. No specific chemical or physical parameter alone correlated with the surface roughness.

scholarly journals Analysis of Surface Roughness and Flank Wear Using the Taguchi Method in Milling of NiTi Shape Memory Alloy with Uncoated Tools

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1259
Author(s):  
Emre Altas ◽  
Hasan Gokkaya ◽  
Meltem Altin Karatas ◽  
Dervis Ozkan
Keyword(s):  
Surface Roughness ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Flank Wear ◽  
Cutting Tools ◽  
Dominant Factor ◽  
Niti Shape Memory Alloy ◽  
Machining Parameters ◽  
Nose Radius ◽  
Dry Cutting

The aim of this study was to optimize machining parameters to obtain the smallest average surface roughness (Ra) and flank wear (Vb) values as a result of the surface milling of a nickel-titanium (NiTi) shape memory alloy (SMA) with uncoated cutting tools with different nose radius (rε) under dry cutting conditions. Tungsten carbide cutting tools with different rε (0.4 mm and 0.8 mm) were used in milling operations. The milling process was performed as lateral/surface cutting at three different cutting speeds (Vc) (20, 35 and 50 m/min), feed rates (fz) (0.03, 0.07 and 0.14 mm/tooth) and a constant axial cutting depth (0.7 mm). The effects of machining parameters in milling experiments were investigated based on the Taguchi L18 (21 × 32) orthogonal sequence, and the data obtained were analyzed using the Minitab 17 software. To determine the effects of processing parameters on Ra and Vb, analysis of variance (ANOVA) was used. The analysis results reveal that the dominant factor affecting the Ra is the cutting tool rε, while the main factor affecting Vb is the fz. Since the predicted values and measured values are very close to each other, it can be said that optimization is correct according to the validation test results.

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