scholarly journals Miniaturization re-establishes symmetry in the wing folding patterns of featherwing beetles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pyotr N. Petrov ◽  
Sergey E. Farisenkov ◽  
Alexey A. Polilov
Keyword(s):  
Cross Sections ◽  
High Speed ◽  
Laser Scanning ◽  
Video Recording ◽  
Confocal Laser ◽  
Minimum Duration ◽  
Rove Beetles ◽  
Miniature Robots ◽  
Folding Pattern ◽  
Wing Folding

Abstract Most microinsects have feather-like bristled wings, a state known as ptiloptery, but featherwing beetles (family Ptiliidae) are unique among winged microinsects in their ability to fold such wings. An asymmetrical wing folding pattern, found also in the phylogenetically related rove beetles (Staphylinidae), was ancestral for Ptiliidae. Using scanning electron, confocal laser scanning, and optical microscopy, high-speed video recording, and 3D reconstruction, we analyze in detail the symmetrical wing folding pattern and the mechanism of the folding and unfolding of the wings in Acrotrichis sericans (Coleoptera: Ptiliidae) and show how some of the smaller featherwing beetles have reverted to strict symmetry in their wing folding. The wings are folded in three phases by bending along four lines (with the help of wing folding patches on the abdominal tergites) and locked under the closed elytra; they unfold passively in two phases, apparently with the help of the elasticity provided by resilin unevenly distributed in the wing and of convexities forming in the cross-sections of the unfolding wing, making it stiffer. The minimum duration of folding is 3.5 s; unfolding is much more rapid (minimum duration lowest recorded in beetles, 0.038 s). The folding ratio of A. sericans is 3.31 (without setae), which is greater than in any beetle in which it has been measured. The symmetrical wing folding pattern found in A. sericans and in all of the smallest ptiliids, in which ptiloptery is especially pronounced, is the only known example of symmetry re-established during miniaturization. This direction of evolution is remarkable because miniaturization is known to result in various asymmetries, while in this case miniaturization was accompanied by reversal to symmetry, probably associated with the evolution of ptiloptery. Our results on the pattern and mechanisms of wing folding and unfolding can be used in robotics for developing miniature biomimetic robots: the mechanisms of wing folding and unfolding in Ptiliidae present a challenge to engineers who currently work at designing ever smaller flying robots and may eventually produce miniature robots with foldable wings.

Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions

2022 ◽  
pp. 002203452110617
Author(s):  
F.S. de Lucena ◽  
S.H. Lewis ◽  
A.P.P. Fugolin ◽  
A.Y. Furuse ◽  
J.L. Ferracane ◽  
...  
Keyword(s):  
Bond Strength ◽  
Cross Sections ◽  
Laser Scanning ◽  
Adhesive System ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Gap Formation ◽  
Bond Stability ◽  
Occlusal Surfaces ◽  
Before And After

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey’s test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

Intra-operative application of confocal endomicroscopy using a rigid endoscope

2013 ◽  
Vol 127 (6) ◽  
pp. 599-604 ◽  
Author(s):  
T Just ◽  
H W Pau
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Confocal Laser ◽  
Scanning System ◽  
Tissue Pressure ◽  
Perforation Plate ◽  
Confocal Endomicroscopy ◽  
Rigid Endoscope ◽  
Operative Evaluation

AbstractObjective:To introduce the application of confocal endomicroscopy during microlaryngoscopy, to enable intra-operative evaluation of human laryngeal epithelium.Methods:A rigid endoscope was connected to the scanner head of a Heidelberg Retina Tomograph II confocal laser scanning system via an adapter. The endoscope was gently placed on the surface of a vocal fold through a laryngoscope during microlaryngoscopy.Results:The application of confocal endomicroscopy using a rigid endoscope enabled technical improvements (i.e. improved image quality, automatic volume scan, and reduced tissue pressure due to the presence of a perforation plate with central hole at the end of the endoscope) which permitted greater sensitivity and improved handling. Confocal endomicroscopy provided good quality, in vivo, en-face images and enabled an assessment of laryngeal epithelium volume.Conclusion:This method enables the surgeon to monitor epithelial changes in pre-malignant lesions. The combination of confocal endomicroscopy together with optical coherence tomography (as a complementary technique that provides optical cross-sections) should be further explored in a formal clinicopathological study.

Thermo-Chemical Dressing of Coarse Grained Diamond Grinding Wheels

2012 ◽  
Vol 565 ◽  
pp. 211-216 ◽  
Author(s):  
Oltmann Riemer ◽  
Yildirim Mutlugünes
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Coarse Grained ◽  
Confocal Laser ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Dressing Method ◽  
Diamond Sample ◽  
Friction Pressure

This paper deals with a novel dressing method for coarse grained, single layered metal bonded grinding wheels based on the dynamic friction polishing. The diamond friction polishing technique utilizes the thermo-chemical reaction between a diamond sample and a metal tool rotating at high speed. Here, the tips of the diamond grains of a rapidly rotating grinding wheel are thermo-chemically flattened due to the contact with two slowly rotating steel calottes at predetermined friction pressure pd and grinding wheel velocity vsd. Dressing experiments have been carried out changing the friction pressure pd and the grinding wheel velocity vsd. The generated topography of the grinding wheel has been characterized by a confocal laser scanning microscope. Thus, the flattened grains with an average grain protrusion hk could be measured and the influence of the friction pressure and grinding wheel velocity on the dressing process is shown.

Elastic Wing Deployments in Beetles and Their Folding Mechanisms

2015 ◽  
Author(s):  
Kazuya Saito ◽  
Yoji Okabe
Keyword(s):  
High Speed ◽  
Wing Development ◽  
Deployable Structures ◽  
Ladybird Beetle ◽  
Rove Beetles ◽  
Insect Wing ◽  
Symmetric Pattern ◽  
Strength And Stiffness ◽  
Sufficient Strength ◽  
Wing Folding

Foldable hindwings in beetles are one of the ultimate deployable structures. They have sufficient strength and stiffness to tolerate 20–1000 beats per second in the flight position, although they can be folded and unfolded nearly instantly depending on the situation. This study focuses on a group of beetles that have unfolding-stable-type wings and aims to reveal their wing-folding/unfolding mechanisms. These beetles use their wing elasticity for deployment and can therefore quickly take off. First, on the basis of the reports of entomologists, the authors describe the factors related to the actuation of insect wing folding and unfolding. Then, the detailed motions involved in take-off and wing storing in ladybird beetles and rove beetles are observed by a high-speed camera. The analysis of these movies reveals the detailed processes of wing-unfolding and folding in these two species. Intrinsic elasticity plays a major role in wing development in both species. In the case of wing storing, a ladybird beetle folds its hindwings into a symmetric pattern using a simple up–down movement of the abdomen, whereas rove beetles also use their abdomens for wing-folding, but their movements are more complex, and the crease patterns are asymmetric. Finally, the characteristics of each wing-folding mechanism are summarized and the potential for engineering applications are discussed. Wing-folding/unfolding mechanisms in these insects have various unique capabilities which will provide new possibilities for designing deployable structures.

Characteristics of Hydrodynamically Focused Streams for Use in Microscale Particle Image Velocimetry (Micro-PIV)

2006 ◽  
Author(s):  
Piotr M. Domagalski ◽  
Michal M. Mielnik ◽  
Ingrid Lunde ◽  
Lars R. Sætran
Keyword(s):  
Particle Image Velocimetry ◽  
Cross Sections ◽  
Laser Scanning ◽  
Particle Image ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Hydrodynamic Focusing ◽  
Micro Piv ◽  
Image Velocimetry ◽  
Sheet Width

This paper presents the characteristics of hydrodynamically focused streams to be used in Microscale Particle Image Velocimetry (micro-PIV). The investigation was done by means of Confocal Laser Scanning Microscopy (CLSM) in channels of cross sections 260 × 200 μm and 1040 × 800 μm, within the downstream velocities range from 0,1 to 2,5 cm/s. The formulation of a curvature of the sheet, its dependence on the side stream ratio and overall downstream velocity is discussed qualitatively and quantitatively. The results show that the curvature is highly dependent on the velocities of the system. Sheet characteristics such as curvature and observed sheet width variation become amplified with higher velocities. This leads to conclusion that hydrodynamic focusing is promising as a selective seeding technique for use in micro-PIV up to velocities of few cm/s. However, the fact that this is the upper velocity range in microfluidics, renders the SeS-PIV technique as a very suitable tool for complicated flows visualization.

Study on Choice of Reference Planes for 3D Machined Surface Roughness of SiCp/Al Composites during High Speed Milling Process

2010 ◽  
Vol 150-151 ◽  
pp. 129-132 ◽  
Author(s):  
Yang Jun Wang ◽  
Ming Zhou ◽  
Yuan Jing Zhang
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Chemical Vapour ◽  
Least Square ◽  
Confocal Laser ◽  
Machined Surface ◽  
High Speed Milling ◽  
Least Square Fitting ◽  
Fitting Method ◽  
Least Square Fitting Method

This paper presents an experimental study in high speed milling of SiCp/Al composites. Machining tests were carried out on a high speed milling machine by using chemical vapour deposition (CVD) diamond coated tools. The surface micro-topography was tested by the OLS3000 Confocal Laser Scanning Microscope. The Gaussian filtering method and the least square fitting method were used to treat the measured results. Two methods are compared according to the effect on keeping important original surface’s character. The results showed that the least square fitting method is suitable due to its good accordance to the original surface’s character.

Suspension Mixing and Segregation in 1D, 2D, and 3D Flows

2007 ◽  
Author(s):  
James F. Gilchrist ◽  
Changbao Gao
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Chaotic Advection ◽  
Confocal Laser ◽  
Particle Velocities ◽  
Complicated Geometries ◽  
3D Flows ◽  
2D And 3D ◽  
Suspension Structure

Particles in concentrated flowing suspension in pressure-driven flows tend to migrate away from the walls toward the center of the channel. Demixing due to shear-induced migration inhibits mixing and near wall transport. We investigate the competition between mixing and segregation in flows with complicated geometries that generate 3D chaotic advection, resulting in nontrivial concentration patterns. Using high-speed confocal laser scanning microscopy, we directly image the microspheres to measure the interplay between chaotic advection and the 3D spatial concentration profile, local particle velocities, and suspension structure.

Research of the Treatment Parameters Effects on the Layer Formation during Wire-Feed Laser-TIG Deposition with Aluminum Alloy

2019 ◽  
Vol 822 ◽  
pp. 496-503
Author(s):  
V.V. Somonov ◽  
I.A. Tsibulskiy ◽  
Nikita G. Kislov ◽  
Alexander A. Lanin
Keyword(s):  
Cross Sections ◽  
Laser Power ◽  
High Speed ◽  
Video Recording ◽  
Experimental Studies ◽  
Metallographic Analysis ◽  
Layer Formation ◽  
Aluminum Wire ◽  
High Speed Video ◽  
Wire Feed

The paper presents the results of an investigation of the influence parameters of laser radiation on the formation of the deposition layer during laser-TIG direct deposition of aluminum wire. Experimental studies have focused on the determination the dependence shape of layer on the laser power, the distance between axis of laser beam and axis of arc, arc parameters. High-speed video recording of the process was carried out. The metallographic analysis of cross-sections of the samples was performed.

Distribution of Biomolecules in Porous Nitrocellulose Membrane Pads Using Confocal Laser Scanning Microscopy and High-Speed Cameras

2013 ◽  
Vol 85 (7) ◽  
pp. 3723-3729 ◽  
Author(s):  
Liyakat Hamid Mujawar ◽  
Abid Aslam Maan ◽  
Muhammad Kashif Iqbal Khan ◽  
Willem Norde ◽  
Aart van Amerongen
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
High Speed ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser ◽  
Nitrocellulose Membrane
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