A technique for measurement of a prism apex angle by optical angle sensors with a reference artefact

2021 ◽  
Author(s):  
Yuki Shimizu ◽  
Xu Ma ◽  
Hiraku Matsukuma ◽  
Wei Gao
Keyword(s):  
Apex Angle

scholarly journals DESIGNING A TEMPORARY COLD PROTECTIVE GEAR CONSTRUCTED BY FOLDING NEWSPRINT PAPER CONSIDERING HEAT-RETAINING PROPERTY AND RIGIDITY

2021 ◽  
Vol 1 ◽  
pp. 1123-1132
Author(s):  
Tatsuya Oda ◽  
Shigeru Wesugi
Keyword(s):  
Natural Disaster ◽  
Cold Season ◽  
Apex Angle ◽  
The Body ◽  
Experimental Results ◽  
Protective Gear ◽  
Significant Difference ◽  
Body Shapes

AbstractDuring the cold season, the cold protective products are often short during evacuation life after a natural disaster. If evacuees can make and wear simple cold protective gears by using materials obtainable on site, it will reduce the burden on the evacuees in emergent situation. Therefore, we investigated the structure constructed by folding newsprint paper, which can improve the heat retention effect and be applied to various body shapes. Focusing on the glide reflection structure repeating a smaller chamber, the basic size was determined by experiments with reference to the accordion shape, and the experimental results indicated that the heat retention effect was significantly greater than that of a mere air layer and those of ordinary fabrics. Next, it was found that the apex angle of structure had no significant difference in the heat retention effect. Then, the dimensions of the structure were determined to maintain the air layer under the pressure of the clothes by simulation of structural analyses. Finally, we made a temporary cold protective gear that can practically cover the trunk of the body and found that the heat retention effect was significantly higher than that of unprocessed newsprint and that of accordion shape.

scholarly journals The evolution of gastropod shell form: a developmental model illustrating the roles of heterochrony and non-heterochronic changes

1992 ◽  
Vol 6 ◽  
pp. 245-245
Author(s):  
Sean H. Rice
Keyword(s):  
Growth Rate ◽  
Specific Pattern ◽  
Apex Angle ◽  
Developmental Model ◽  
Gastropod Shell ◽  
Shell Form ◽  
Marine Snails ◽  
Highly Sensitive ◽  
Highly Correlated ◽  
Shell Production

The shape of an isometric gastropod shell can be described completely by specifying the pattern of shell secretion around the aperture (relative to aperture size) and the growth rate of the aperture itself. These descriptors provide a “natural” morphometric in that they correspond to the specific biological processes involved in constructing the shell.Describing shell form in this way allows us to specify what developmental changes must occur during the transition of one shell form to another. In particular, we can distinguish between transitions that can occur through purely heterochronic processes (changes in growth rate) and those that require a change in the specific pattern in which cells of the mantle lay down shell. We can also investigate just what changes occur during the ontogeny of non-isometric shells.Any change in either the pattern of shell secretion or the growth rate of the animal leads to changes in a number of classical morphometric measures, such as apex angle and whorl expansion rate. Those transformations resulting from changes in growth rate, however, are much more predictable than those resulting from changes in the pattern of shell production. A slight increase in the growth rate of the animal, for instance, produces a correspondingly slight increase in the apex angle and the rate of whorl expansion. By contrast, the consequences of a slight change in the pattern of shell production are highly sensitive to just how that change was achieved.Data from 8 genera of marine snails show that the variance within each genus, relative to the variance among all genera, is smaller for measures of aperture shape (which can only be altered through a change in the pattern of secretion of shell material) than for characters that can change through heterochronic transformations (such as apex angle). Furthermore, the shell forms of a number of non isometric shells can be described by a constant pattern of shell production and a variable growth rate.Heterochronic changes thus appear to be the preferred mechanism for changing phenotype in gastropod shells. Those characters that can only be altered by changing the pattern of shell production around the mantle, such as aperture shape, appear to be more conservative than those that can be changed through purely heterochronic transitions. This is consistent with the idea that mutations which alter many characters in a highly correlated manner have a higher probability of being favored by selection than those with relatively unpredictable consequences.

scholarly journals Rational synthesis of an atomically precise carboncone under mild conditions

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw0982 ◽  
Author(s):  
Zheng-Zhong Zhu ◽  
Zuo-Chang Chen ◽  
Yang-Rong Yao ◽  
Cun-Hao Cui ◽  
Shu-Hui Li ◽  
...  
Keyword(s):  
Apex Angle ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
X Ray ◽  
Carbon Allotropes ◽  
X Ray Crystallography ◽  
Mild Conditions ◽  
Research Opportunity ◽  
Insight Into ◽  
Structural Strain

Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.

Investigation of Relationship between Instrumented Indentation Nominal Hardness and Reduced Elastic Modulus with Large Apex Angle Indenter

2012 ◽  
Vol 198-199 ◽  
pp. 193-196
Author(s):  
De Jun Ma ◽  
Jun Hong Guo ◽  
Wei Chen ◽  
Zhong Kang Song
Keyword(s):  
Elastic Modulus ◽  
Measurement Error ◽  
Apex Angle ◽  
Instrumented Indentation ◽  
Included Angle ◽  
Cube Corner ◽  
Order Polynomial ◽  
Strength Material ◽  
Relationship Of ◽  
The Relationship

Based on dimensional analysis, finite element numerical calculation is undertaken on elastic–plastic solids to investigate the relationship between instrumented indentation nominal hardness Hn and reduced elastic modulus Er for three different apex angle indenters. The half-included angles of axisymetric conical indenter models are 62.9°, 70.3°and 85.566° which are corresponding to the real indenters of cube corner indenter with 60° face angle, Berkovich indenter with 65.27° face angle and cube corner indenter with 85° face angle, respectively. The relationship between a nominal hardness/reduced elastic modulus (Hn/Er) and elastic work/total indentation work (We/Wt) is established with a sixth-order polynomial form for each apex angle indenter. For rigid indenter of instrumented indentation model, reduced elastic modulus Er=1/[(1+v2)/E], where E and v are elastic modulus and Poisson’s ratio of the indented material. Therefore, Hn/Er–We/Wt relationship can be used to give estimates of E. Accuracy estimation for the each relationship of each half-included angle indenter shows that the large half-included angle of 85.566° gives better Er measurement error of +11.56% for a low yield strength material(e.g., materials for which σy=100MPa, n=0 and E=200GPa), while for the smaller half-included angle of 62.9° or 70.3° indenter, the measurement error is > ±12.74%. The research in this paper confirms that Hn/Er–We/Wt relationship of large apex angle indenter such as 85.566° half-included angle is recommended to be used for estimating the elastic modulus E of indented material.

Study on Reducing Apex Angle Burnt Rate during Laser Cutting Based on Path Transformation

2012 ◽  
Vol 39 (8) ◽  
pp. 0803006
Author(s):  
邓前松 Deng Qiansong ◽  
赵辰丰 Zhao Chenfeng ◽  
陈亮 Chen Liang ◽  
石明国 Shi Mingguo ◽  
杨卫红 Yang Weihong ◽  
...  
Keyword(s):  
Laser Cutting ◽  
Apex Angle

Numerical Computation of Apex Angle Effects on Taylor Vortices in Rotating Conical Cylinders Systems

2002 ◽  
Vol 35 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Mohamed Nabil Noui-Mehidi ◽  
Naoto Ohmura ◽  
Kunio Kataoka
Keyword(s):  
Numerical Computation ◽  
Apex Angle ◽  
Taylor Vortices

scholarly journals Approximation algorithms for tours of orientation-varying view cones

2020 ◽  
Vol 39 (4) ◽  
pp. 389-401
Author(s):  
Nikolaos Stefas ◽  
Patrick A Plonski ◽  
Volkan Isler
Keyword(s):  
Approximation Algorithm ◽  
Ground Plane ◽  
Orientation Angle ◽  
Apex Angle ◽  
Field Of View ◽  
Plane Normal ◽  
Polynomial Time Approximation Algorithm ◽  
New Variant ◽  
Angle Difference ◽  
Novel Variant

This article considers the problem of finding a shortest tour to visit viewing sets of points on a plane. Each viewing set is represented as an inverted view cone with apex angle [Formula: see text] and height [Formula: see text]. The apex of each cone is restricted to lie on the ground plane. Its orientation angle (tilt) [Formula: see text] is the angle difference between the cone bisector and the ground plane normal. This is a novel variant of the 3D Traveling Salesman Problem with Neighborhoods (TSPN) called Cone-TSPN. One application of Cone-TSPN is to compute a trajectory to observe a given set of locations with a camera: for each location, we can generate a set of cones whose apex and orientation angles [Formula: see text] and [Formula: see text] correspond to the camera’s field of view and tilt. The height of each cone [Formula: see text] corresponds to the desired resolution. Recently, Plonski and Isler presented an approximation algorithm for Cone-TSPN for the case where all cones have a uniform orientation angle of [Formula: see text]. We study a new variant of Cone-TSPN where we relax this constraint and allow the cones to have non-uniform orientations. We call this problem Tilted Cone-TSPN and present a polynomial-time approximation algorithm with ratio [Formula: see text], where [Formula: see text] is the set of all cone heights. We demonstrate through simulations that our algorithm can be implemented in a practical way and that by exploiting the structure of the cones we can achieve shorter tours. Finally, we present experimental results from various agriculture applications that show the benefit of considering view angles for path planning.

scholarly journals Models for evaluating craters morphology, relation of indentation hardness and uniaxial compressive strength via a flat-end indenter

2018 ◽  
Vol 10 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Ligang Zhang ◽  
Xiao Fei Fu ◽  
G. R. Liu ◽  
Shi Bin Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Internal Friction ◽  
Uniaxial Compressive Strength ◽  
Poisson’S Ratio ◽  
Failure Process ◽  
Apex Angle ◽  
Poisson's Ratio ◽  
Percentage Error ◽  
Indentation Hardness ◽  
Angle Of Internal Friction

AbstractIn this work, the intensive theoretical study and laboratory tests are conducted to evaluate the craters morphology via the flat-ended indenter test, relationship of indentation hardness (HRI) and uniaxial compressive strength (UCS). Based on the stress distribution, failure process and Mohr–Coulomb failure criterion, the mathematical mechanical models are presented to express the formation conditions of “pulverized zone” and “volume break”. Moreover, a set of equations relating the depth and apex angle of craters, the ratio of indentation hardness and uniaxial compressive strength, the angle of internal friction and Poisson’s ratio are obtained. The depth, apex angle of craters and ratio of indentation hardness and uniaxial compressive strength are all affected by the angle of internal friction and Poisson’s ratio. The proposed models are also verified by experiments of rock samples which are cored from Da Qing oilfield, the percentage error between the test and calculated results for depth, apex angle of craters and the ratio of HRI and UCS are mainly in the range of –1.41%–8.92%, –5.91%–3.94% and –8.22%–13.22% respectively for siltstone, volcanic tuff, volcanic breccia, shale, sand stone and glutenite except mudstone, which demonstrates that our proposed models are robust and effective for brittle rock.

Fundamental aspects of the vortex flow on cones. Angular characterization of hyperlifting vortex torques; the law of filiation

2008 ◽  
Vol 86 (8) ◽  
pp. 1027-1031 ◽  
Author(s):  
A Abene ◽  
V Dubois
Keyword(s):  
Wind Tunnel ◽  
Vortex Flow ◽  
Secondary Structures ◽  
Current Theory ◽  
Vortex Structures ◽  
Apex Angle ◽  
Slender Bodies ◽  
The Law

This paper describes in detail the fundamental aspects of the vortex flow developed on the upper surface of a cone having an apex angle of 68.6°. It is one of a large number of studies carried out in the wind tunnel of the Valenciennes University aerodynamics and hydrodynamics laboratory whereby visualizations have enabled the flow of vortex structures to be monitored and consequently their development and positioning, under the influence of apex angles and at increasing angles of incidence, to be determined and defined. The existence and the preferential nature of intervortex angles are here confirmed and it has been found, by analogy with studies carried out on other types of slender bodies, that the law of filiation is applicable to the angular characterization of hyperlifting vortex torques and to the angular correspondence existing between their main and secondary structures. These findings suggest that there is a certain universality in the behaviour of these properties although no current theory would seem to be able as yet to provide a straightforward explanation of the phenomena.PACS Nos.: 44, 47

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