Small theropod and bird teeth from the late Cretaceous (late Campanian) Judith River Group, Alberta

2002 ◽  
Vol 76 (4) ◽  
pp. 751-763 ◽  
Author(s):  
Julia T. Sankey ◽  
Donald B. Brinkman ◽  
Merrilee Guenther ◽  
Philip J. Currie
Keyword(s):  
Late Cretaceous ◽  
Flat Surface ◽  
Flat Surfaces ◽  
Wear Pattern ◽  
A Share

A collection of over 1,700 small theropod teeth from the Judith River Group (Campanian;˜79.5–74 Ma) allows our understanding of the diversity and variation of small theropods in this assemblage to be refined. In addition to the previously recognized taxa, a series of morphologically distinct groups are recognized that may represent distinct taxa in some cases. Teeth with the Paronychodon-like features of a flat surface with longitudinal ridges on one side are resolved into a few discrete morphotypes. Two of these are included in Paronychodon lacustris and two additional morphotypes are hypothesized to represent distinct taxa, here referred to as ?Dromaeosaurus morphotype A and Genus and species indet. A. The teeth of Paronychodon lacustris and ?Dromaeosaurus morphotype A share a distinctive wear pattern that suggests tooth functioning involved contact between the flat surfaces of opposing teeth. Two species of Richardoestesia, R. gilmorei and R. isosceles, are present in the assemblage. Additionally, bird teeth are identified in the assemblage and are described in this review.Bivariate plots were used to document the variation in the theropod teeth, especially in the features that distinguish between Richardoestesia gilmorei, R. isosceles, Saurornitholestes, and Dromaeosaurus. Considerable overlap is present in all plots, so although the teeth are morphologically distinct, they are not easily distinguished by quantitative means.

scholarly journals Designing bioinspired surfaces for water collection from fog

2018 ◽  
Vol 377 (2138) ◽  
pp. 20180269 ◽  
Author(s):  
Dev Gurera ◽  
Bharat Bhushan
Keyword(s):  
Flat Surface ◽  
Unit Area ◽  
Water Repellency ◽  
Vertical Axis ◽  
Collection Rate ◽  
Flat Surfaces ◽  
Single Cone ◽  
Water Collection ◽  
The Difference ◽  
Conical Surfaces

A systematic study is presented on various water collectors, bioinspired by desert beetles, desert grass and cacti. Three water collecting mechanisms including heterogeneous wettability, grooved surfaces, and Laplace pressure gradient, were investigated on flat, cylindrical, conical surfaces, and conical array. It is found that higher water repellency in flat surfaces results in higher water collection rate and inclination angle (with respect to the vertical axis) has little effect. Surfaces with heterogeneous wettability have higher water collection rate than surfaces with homogeneous wettability. Both cylindrical and conical surfaces resulted in comparable water collection rate. However, only the cone transported the water droplets to its base. Heterogeneity, higher inclination and grooves increased the water collection rate. A cone has a higher collection rate per unit area than a flat surface with the same wettability. An array of cones has higher collection rate per unit area than a single cone, because droplets in a conical array coalesce, leading to higher frequency of droplets falling. Adding heterogeneity further increases the difference. Based on the findings, scaled-up designs of beetle-, grass- and cactus-inspired surfaces and nets are presented. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.

scholarly journals Laser-written colours on silver: optical effect of alumina coating

Nanophotonics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 807-822 ◽  
Author(s):  
Jean-Michel Guay ◽  
Antonino Calà Lesina ◽  
Graham Killaire ◽  
Peter G. Gordon ◽  
Choloong Hahn ◽  
...  
Keyword(s):  
Time Domain ◽  
Finite Difference Time Domain ◽  
Flat Surface ◽  
Atomic Layer ◽  
Alumina Coating ◽  
Optical Effect ◽  
Alumina Film ◽  
Flat Surfaces ◽  
Layer Deposition ◽  
Difference Time

AbstractIn this paper we discuss the optical response of laser-written plasmonic colours on silver coated via the atomic layer deposition of alumina. These colours are due to nanoparticles distributed on a flat surface and on a surface with periodic topographical features (i.e. ripples). The colours are observed to shift with increasing alumina film thickness. The colours produced by surfaces with ripples recover their original vibrancy and hue after the deposition of film of thickness ~60 nm, while colours arising from flat surfaces gradually fade and never recover. Analysis of the surfaces identifies periodic topographical features to be responsible for this behaviour. Finite-difference time-domain simulations unravel the role played by the alumina thickness in colour formation and confirm the rotations and recovery of colours for increasing alumina thickness. The coloured surfaces were evaluated for applications in colourimetric and radiometric sensing showing large sensitivities of up to 3.06/nm and 3.19 nm/nm, respectively. The colourimetric and radiometric sensitivities are observed to be colour dependent.

A compact stair-climbing wheelchair with two 3-DOF legs and a 1-DOF base

2016 ◽  
Vol 43 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Chang-Hyuk Lee ◽  
Kyung-min Lee ◽  
Jehong Yoo ◽  
In-su Kim ◽  
Young-bong Bang
Keyword(s):  
Degrees Of Freedom ◽  
Flat Surface ◽  
Estimation Method ◽  
Stable Condition ◽  
Stair Climbing ◽  
Joint Power ◽  
Content Type ◽  
Flat Surfaces ◽  
Simple Estimation ◽  
The Stability

Purpose – The purpose of this paper is to describe a compact wheelchair, which has two 3-degrees of freedom (DOF) legs and a 1-DOF base (the total DOF of the leg system is 7) for stair-climbing, and wheels for flat surface driving. Design/methodology/approach – The proposed wheelchair climbs stairs using the two 3-DOF legs with boomerang-shaped feet. The leg mechanisms are folded into the compact wheelchair body when the wheelchair moves over flat surfaces. The authors also propose a simple estimation method of stair shape using laser distance sensors, and a dual motor driving system to increase joint power. Findings – The proposed wheelchair can climb arbitrary height and width stairs by itself, even when they are slightly curved. During climbing, the trajectory of the seat position is linear to guarantee the comfort of rider, and the wheelchair always keeps a stable condition to ensure the stability in an emergency stop. Originality/value – The wheelchair mechanism with foldable legs and driving wheels enables smooth stair climbing, efficient flat surface driving and additional useful motions such as standing and tilting.

Fabrication of Porous Metal Bonded Diamond Grinding Wheels for Flat-Surface Nanomachining

MRS Bulletin ◽  
2001 ◽  
Vol 26 (7) ◽  
pp. 544-546 ◽  
Author(s):  
Koji Matsumaru ◽  
Atsushi Takata
Keyword(s):  
Flat Surface ◽  
Porous Metal ◽  
Small Scale ◽  
Grinding Wheels ◽  
Related Area ◽  
Flat Surfaces ◽  
Diamond Grinding ◽  
The Creation

The articles thus far in this MRS Bulletin issue on Emerging Methods for Micro- and Nanofabrication have addressed the creation of structures or devices on a small scale. What is implicit in some of these articles is that a substrate of sufficient flatness is available upon which to build these structures in a controlled way. A related area, therefore, is the formation of these flat surfaces, as well as the development of the tools to make them.

The adhesive attitudes of some gill-parasitic capsalid monogeneans

1991 ◽  
Vol 65 (4) ◽  
pp. 280-285 ◽  
Author(s):  
I. D. Whittington ◽  
G. C. Kearn
Keyword(s):  
Teleost Fish ◽  
Flat Surface ◽  
Gill Arch ◽  
Pharyngeal Tooth ◽  
Flat Surfaces ◽  
Coral Trout ◽  
Gill Chamber ◽  
Attachment Sites ◽  
Secondary Lamellae ◽  
Gill Raker

ABSTRACTA description is given of three contrasting adhesive attitudes exhibited by three species of capsalid monogeneans from the gills of three different species of teleost fish from Heron Island, Queensland, Australia. The proximal end of the primary lamella of the coral trout, Plectropomus maculatus has a wide inner border, free from secondary lamellae, on each flat face. The haptor of Trochopus plectropomi is small enough to attach to this flat surface without folding. Benedenia sp. 1 attaches itself to the gills of stripey, Lutjanus carponatatus, by folding the haptor longitudinally around the inner edge of the primary lamella. Most specimens of T. plectropomi and all specimens of Benedenia sp. 1 were orientated with the anterior end projecting towards the tip of the primary lamella. Benedenia sp. 2 generally prefers relatively flat surfaces in the gill chamber but is more versatile in its choice of attachment sites on its host, the blacktip cod, Epinephelus fasciatus; two specimens were attached to the gill arch, one to a gill raker and one to the dorsal pharyngeal tooth pad.

Role of Two-Dimensional Surface Characteristics in Pictorial Depth Perception

1978 ◽  
Vol 46 (3) ◽  
pp. 875-881 ◽  
Author(s):  
Margaret A. Hagen ◽  
Rochelle Glick ◽  
Barbara Morse
Keyword(s):  
Error Rate ◽  
Flat Surface ◽  
Relative Size ◽  
Surface Characteristics ◽  
Picture Perception ◽  
Essential Difference ◽  
Glass Pane ◽  
Flat Surfaces ◽  
Pictorial Perception ◽  
Clear Glass

The purpose of the present experiment was to test the hypothesis that flat surface information for the plane of projection is the essential difference between ordinary and pictorial perception. Adults were asked to make relative size judgments of pairs of squares and triangles placed and pictured at various distances. The conditions were: real scene controls, life-size slides and prints, and real scenes viewed through clear glass, textured glass, a screen and a 50-mm lens. The error rate was significantly lower with real scenes than with either slides or prints which did not differ. The control data for real scenes were used for comparison to test for the effects of interposed flat surfaces on size judgments of real scenes. Viewing real scenes through either a clear glass pane or a 50-mm lens increased the error rate two and one-half times that of the controls for real scenes. Neither textured glass nor a screen significantly affected error rate. Results were interpreted as supporting the hypothesis that information about a flat surface for the plane of projection is the critical variable determining the special character of picture perception.

scholarly journals Performance of PV Panel Mounting Structure for Flat Surface and Roof-Top in UAE Climatic Conditions

2015 ◽  
Vol 07 (1) ◽  
Keyword(s):  
High Probability ◽  
Flat Surface ◽  
Air Flow ◽  
Climatic Conditions ◽  
Pv System ◽  
Flat Surfaces ◽  
Pv Panel ◽  
Short Span ◽  
Flat Roof ◽  
Surface Mounting

PV Panel mounting structure for ground, flat surface and rooftops are getting common and gaining their popularity for several reasons, with availability of vast land that can easily be turned into flat surfaces and flat roof tops of buildings, there is a high probability of such products getting common in short span of time in this region. Conventional mounting structures require ample amount of time for them to be ready for installation, such flat surface mounting structures reduces or eliminates a huge chunk of expense. The efficiency is effected due to the tilt which is obvious, but the effect on performance of the rooftop PV system due to temperature and less air flow is discussed in this paper.

scholarly journals Tendon-derived biomimetic surface topographies induce phenotypic maintenance of tenocytes in vitro

2020 ◽  
Author(s):  
Aysegul Dede Eren ◽  
Aliaksei Vasilevich ◽  
E. Deniz Eren ◽  
Phanikrishna Sudarsanam ◽  
Urandelger Tuvshindorj ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Shape ◽  
Flat Surface ◽  
Flat Surfaces ◽  
Tissue Culture Polystyrene ◽  
Surface Topographies ◽  
And Function ◽  
Shape Changes

AbstractThe tenocyte niche contains biochemical and biophysical signals that are needed for tendon homeostasis. The tenocyte phenotype is correlated with cell shape in vivo and in vitro, and shape-modifying cues are needed for tenocyte phenotypical maintenance. Indeed, cell shape changes from elongated to spread when cultured on a flat surface, and rat tenocytes lose the expression of phenotypical markers throughout five passages. We hypothesized that tendon gene expression can be preserved by culturing cells in the native tendon shape. To this end, we reproduced the tendon topographical landscape into tissue culture polystyrene, using imprinting technology. We confirmed that the imprints forced the cells into a more elongated shape, which correlated with the level of Scleraxis expression. When we cultured the tenocytes for seven days on flat surfaces and tendon imprints, we observed a decline in tenogenic marker expression on flat but not on imprints. This research demonstrates that native tendon topography is an important factor contributing to the tenocyte phenotype. Tendon imprints therefore provide a powerful platform to explore the effect of instructive cues originating from native tendon topography on guiding cell shape, phenotype and function of tendon-related cells.

Formation of quality indicators for flat surfaces of machine parts when running them with a reinforcing roller

2021 ◽  
pp. 401-405
Author(s):  
V.I. Butenko ◽  
Ph.A. Pastukhov
Keyword(s):  
Quality Indicators ◽  
Flat Surface ◽  
Rolling Force ◽  
Functional Dependence ◽  
Roughness Parameter ◽  
Technological Problem ◽  
Flat Surfaces ◽  
Machine Parts ◽  
Rolling Mode

The forming of parameters of quality of parts flat surfaces during their rolling by strengthening roller is studied and it is shown that for each value of rolling force there are extremely achievable indicators of quality of the surface layer. It has been established that the spread of quality indicators values on the strengthened surface of the part is stabilized and becomes minimal after three passes of the roller. The functional dependence of the roughness parameter value of the part flat surface on it’s previous value and rolling mode is obtained, which allows solving a number of technological problem.

Prototype Model of Walking Robot

2014 ◽  
Vol 613 ◽  
pp. 21-28 ◽  
Author(s):  
Tadeusz Mikolajczyk ◽  
Tomasz Fas ◽  
Tomasz Malinowski ◽  
Łukasz Romanowski
Keyword(s):  
Control System ◽  
Flat Surface ◽  
Degree Of Freedom ◽  
Prototype Model ◽  
Walking Robot ◽  
Flat Surfaces ◽  
Simple Idea ◽  
Centre Of Gravity

The purpose of this paper is to elaborate not on the bionic pattern of walking robot. Our own simple idea of 4 degree of freedom (DOF) walking robot with the ability to walk on flat surfaces, rotate and climbing upstairs was made using vertical moved legs with rotary foot and additional controlled mass. In this paper, based on former idea, prototype model for only flat surface walking task 3 DOF were presented. Parts of the robot are moving thanks to servo motors. The paper contains kinematics and centre of gravity analysis, presentation of robot and its control system made using Pololu controller. Conducted experiments confirmed presented idea.

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