The Relationship between Texture Gradient and Perceived Slant-in-Depth: Direct or Mediated?

Perception ◽  
1981 ◽  
Vol 10 (6) ◽  
pp. 695-702 ◽  
Author(s):  
William Epstein
Keyword(s):  
Surface Texture ◽  
Direct Perception ◽  
Texture Gradient ◽  
Textured Surface ◽  
Perceptual Representation ◽  
Rectangular Grid ◽  
Optical Texture ◽  
Rectangular Grids ◽  
Interstimulus Intervals ◽  
The Relationship

Judgments were obtained of the surface texture and rotation in depth of a briefly-exposed monocularly-viewed rectangular grid rotated in depth and a set of projective equivalents of the grid presented in the frontalparallel plane. The judgments were secured when the grids were presented alone and when they were followed by a masking textured surface after interstimulus intervals (ISIs) ranging from 0 to 120 ms. In the absence of the mask judged texture varied corresponding to the variations of optical texture both for the rotated rectangular grids and the frontalparallel projections. Judgements of orientation in the absence of the mask varied corresponding to the variations in objective orientation for the rectangular grid and corresponding to the projective equivalent rotations for the frontalparallel projections. Introduction of the mask at ISI = 0 led to disruption of discriminative gradient and orientation judgments. The degree of disruption decreased as ISI increased. These findings were interpreted as supporting a mediational hypothesis of the relationship between optical texture and perceived slant-in-depth. In contrast to the direct perception hypothesis advanced by Gibson, the mediational hypothesis assigns an important role to the perceptual representation of the optical gradient. When the formation of this representation is arrested by processing of the mask, the relationship between optical texture and perceived slant-in-depth is disrupted.

Numerical and experimental study on the effect of surface texture with roughness orientation considered under a mixed lubrication state

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junru Wang ◽  
Quandai Wang ◽  
Yueyan Li ◽  
Meiling Guo ◽  
Pengyang Li ◽  
...  
Keyword(s):  
Surface Texture ◽  
Surface Texturing ◽  
Mixed Lubrication ◽  
Laser Surface ◽  
Geometric Parameters ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Asperity Contact ◽  
Content Type ◽  
Texture Parameters

Purpose The purpose of this paper is to investigate the effects of surface texture with roughness orientation considered on tribological properties under a mixed lubrication state numerically and experimentally. Design/methodology/approach Based on the average Reynolds equation and asperity contact model, the impacts of surface texture parameters and roughness orientation on lubrication properties have been calculated using finite difference method. Tin–bronze samples with various prescribed surface texture geometric parameters and roughness orientation were fabricated by laser surface texturing technique, and the tribology performance of the textured surface was studied experimentally. Findings The effects of surface geometric parameters and roughness orientation parameters have been discerned. The experimental observations are in good agreement with the numerical prediction, which suggests that the numerical scheme adopted in this work is suitable in capturing the surface texture and roughness effect under mixed lubrication state. Originality/value By meticulously controlling the surface roughness and surface texture geometric characteristics based on the laser surface texturing process, samples with prescribed surface texture parameters and roughness orientation consistent with that in theoretical studies were fabricated and the theoretical model and results were verified experimentally.

The Influence of Surface Texture on Abrasive Wear

2019 ◽  
Vol 823 ◽  
pp. 33-40 ◽  
Author(s):  
Yu Tong Hu ◽  
Yong Yong He ◽  
Wei Wang
Keyword(s):  
Friction Coefficient ◽  
Femtosecond Laser ◽  
Abrasive Wear ◽  
White Light ◽  
Surface Texture ◽  
Friction Surface ◽  
Surface Texturing ◽  
Experimental Results ◽  
The Relationship ◽  
Main Factor

Friction happens everywhere. Abrasives generated in tribological process will result in secondary wear. Abrasive wear is a kind of rather common but harmful wear, which is the main reason for the damage of fifty-percent mechanical components by friction. Surface texturing is an effective method to improve the tribological and lubricating performance of tribo-pairs. In this paper, with different-size diamond particles added into the lubricant and a surface of the tribo-pairs textured by different parameters (diameter and depth) with femtosecond laser, the relationship between the surface texture and the abrasive wear was researched, and the influence of the texture on the abrasive wear was analyzed. The friction experiments were carried out on UMT3. The microstructures were tested and analyzed by SEM, microscope and White Light Interferometer respectively. The experimental results showed that the size of the surface texture, compared with that of abrasives, is the main factor which determines the friction coefficient. As the size of the surface texture is much bigger than that of the abrasives, the texture can accommodate the abrasives efficiently, and thus the friction coefficient is reduced efficiently.

scholarly journals Comparison of the Influences of Surface Texture and Boundary Slip on Tribological Performances

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Qiyin Lin ◽  
Baotong Li
Keyword(s):  
Surface Texture ◽  
Slip Velocity ◽  
Structure Parameters ◽  
Textured Surfaces ◽  
Slider Bearing ◽  
Boundary Slip ◽  
Surface Textures ◽  
Slip Surfaces ◽  
Texture Structure ◽  
The Relationship

Close attentions have been widely paid to the engineering textured and slip surfaces for improving bearing tribological performances. Comparison studies on the tribological characteristics of slip and textured surfaces are carried out in this work. The analysis results point out that the influences of surface texture and boundary slip on tribological performances of slider bearing are strongly similar. For the determinate surface textures, there is one and only value of slip velocity to make the tribological performances of textured and slip surfaces in agreement. The corresponding relation between the slip velocity and the texture structure parameters is also obtained, and the size of slip velocity is directly related to the texture geometry parameters including its position parameters. This study will help us to further understand the relationship between boundary slip and surface texture and also the slip phenomenon.

Effect of Coarse Aggregate Morphology on the Resilient Modulus of Hot-Mix Asphalt

2005 ◽  
Vol 1929 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Tongyan Pan ◽  
Erol Tutumluer ◽  
Samuel H. Carpenter
Keyword(s):  
Surface Texture ◽  
Coarse Aggregate ◽  
Resilient Modulus ◽  
Asphalt Binder ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Maximum Aggregate Size ◽  
Asphalt Mixes ◽  
Aggregate Morphology ◽  
The Relationship

The resilient modulus measured in the indirect tensile mode according to ASTM D 4123 reflects effectively the elastic properties of asphalt mixtures under repeated load. The coarse aggregate morphology quantified by angularity and surface texture properties affects resilient modulus of asphalt mixes; however, the relationship is not yet well understood because of the lack of quantitative measurement of coarse aggregate morphology. This paper presents findings of a laboratory study aimed at investigating the effects of the material properties of the major component on the resilient modulus of asphalt mixes, with the coarse aggregate morphology considered as the principal factor. With modulus tests performed at a temperature of 25°C, using coarse aggregates with more irregular morphologies substantially improved the resilient modulus of asphalt mixtures. An imaging-based angularity index was found to be more closely related to the resilient modulus than an imaging-based surface texture index, as indicated by a higher value of the correlation coefficient. The stiffness of the asphalt binder also had a strong influence on modulus. When the resilient modulus data were grouped on the basis of binder stiffnesses, the agreement between the coarse aggregate morphology and the resilient modulus was significantly improved in each group. Although the changes in aggregate gradation did not significantly affect the relationship between the coarse aggregate morphology and the resilient modulus, decreasing the nominal maximum aggregate size from 19 mm to 9.5 mm indicated an increasing positive influence of aggregate morphology on the resilient modulus of asphalt mixes.

A Design of Coverage Area for Textured Surface of Sliding Journal Bearing Based on Genetic Algorithm

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Hui Zhang ◽  
Mahshid Hafezi ◽  
Guangneng Dong ◽  
Yang Liu
Keyword(s):  
Genetic Algorithm ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Textured Surface ◽  
The Novel ◽  
Eccentricity Ratio ◽  
Coverage Area ◽  
Elliptical Shape ◽  
Bearing Load ◽  
Rectangular Grids

This paper aims to improve the tribological performance of journal bearings by optimizing the coverage area of circular microtextures in divergent region of the sleeve. A numerical model is proposed to calculate the friction coefficient and bearing load of textured journal bearings. The surface of the sleeve is divided into rectangular squares. Textures that located at the center of rectangular grids are assumed to be present or absent, marked as 1 and 0, respectively. Afterward, different texture coverage area arrangements are evolved and selected based on the genetic algorithm (GA). The area of semi-elliptical shape is obtained as the novel and preferable textured coverage area design for journal bearings. Influences of width and eccentricity ratio are discussed, which confirm the semimajor and semiminor axes of the semi-elliptical shape of texture coverage area equal to one-third of the circumferential length and half of the width of the journal bearing, respectively.

Experimental study on friction coefficient and temperature rise of heavy-load grease-lubricated spherical plain bearings with surface texture

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jinlong Shen ◽  
Tong Zhang ◽  
Jimin Xu ◽  
Xiaojun LIU ◽  
Kun Liu
Keyword(s):  
Friction Coefficient ◽  
Temperature Rise ◽  
Surface Texture ◽  
Tribological Performance ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Roughness Parameters ◽  
Heavy Load ◽  
Friction Coefficients ◽  
Content Type

Purpose This paper aims to improve the tribological performance of grease-lubricated spherical plain bearings (SPBs) under heavy load, dimple-type textures were prepared by laser on the outer surface of the inner ring. The influence of roughness parameters of a textured surface on reducing friction coefficient and temperature rise was also explored. Design/methodology/approach This study adopts a laser processing method to fabricate dimple-type textures. Three-dimensional roughness parameters were used to characterize the textured surfaces. The friction coefficients of five SPBs with surface texture and one original commercially available SPB without surface texture under different nominal loads were measured on a self-established test rig. The data of temperature rise were obtained by nine embedded thermal couples. Findings The results indicate that SPBs with textures generally exhibit lower friction coefficients than the original SPB without textures. The dimple depth has a significant influence on improving the tribological performance, which coincides with the analysis by surface roughness parameters. A textured surface with negative Ssk and high Vvc has the minimum temperature rise. Originality/value As it is too difficult to arrange sensors into heavy-load SPBs, there are few reports about the temperature characteristics. Through nine embedded thermal couples, the distribution of temperature rise on the inner ring of SPBs was given in this study. The positive effect of surface texture on reducing temperature rise and friction coefficient was verified, which is beneficial for the design of heavy-load SPBs.

scholarly journals Efficient Sampling Grids for Timber Cruises

2004 ◽  
Vol 21 (2) ◽  
pp. 80-82 ◽  
Author(s):  
John R. Brooks ◽  
Harry V. Wiant
Keyword(s):  
Forest Inventory ◽  
Travel Distance ◽  
Total Field ◽  
Rectangular Grid ◽  
Square Grid ◽  
Efficient Sampling ◽  
Rectangular Grids ◽  
Time Savings

Abstract Equations are provided to permit forest inventory specialists to quantitatively estimate the total field inventory travel distance, and thus time, based solely on inputs of property size, the number of inventory samples desired, and the type of systematic grid employed. Total inventorytravel time is estimated for square and varying rectangular grid spacings for property sizes from 100 to 10,000 ac to estimate the time savings for rectangular grids over square grid patterns for the same number of inventory samples.

Laser Scan System to Establish 3-D Surface Texture and Predict Friction of Pavement

2011 ◽  
Vol 145 ◽  
pp. 339-343 ◽  
Author(s):  
Shih Huang Chen ◽  
Ching Tsung Hung ◽  
Chang Hua Yu ◽  
Hung Wen Chung ◽  
Chia Hao Chen
Keyword(s):  
Surface Texture ◽  
Asphalt Concrete ◽  
Correlation Coefficients ◽  
High Definition ◽  
Porous Asphalt ◽  
3D Texture ◽  
Key Factor ◽  
Stone Mastic Asphalt ◽  
Computer Simulation Program ◽  
The Relationship

Friction of pavement is the most popular tropic which is concerned by drivers and engineers, surface texture are also widely regarded as key factor to influence it. The brief object of this study is to establish the relationship between 3 D texture and friction. In the study, the mixtures include Dense Grade Asphalt Concrete (DGAC), Stone Mastic Asphalt (SMA), and Porous Asphalt (PA). High Definition Scan Texture Machine (HDSTM) with 2D Laser CCD was adopted to measure the 2 D texture of Asphalt concrete specimens, and British Portable Tester (BPN) was also used to evaluate friction of various mixture specimen surfaces. The study was attempted to further create initial 3 D model with data of HDSTM and Computer Simulation Program. Correlation coefficients between the ratio of Surface area in unit area (SA/A) and friction was up to 0.8. SA/A could be regards as the best feasible factor to estimate the mixture surface in the ability of skid resistance, and. Based on above results, 3D texture parameter is remarkable for evaluation of friction and is was worthy of further study.

Destroying Uniformity: Using Fungi to Add a Tactile and Visual Experience to Functional Wood

Leonardo ◽  
2011 ◽  
Vol 44 (2) ◽  
pp. 144-151 ◽  
Author(s):  
Sara C. Robinson
Keyword(s):  
Functional State ◽  
Surface Texture ◽  
Visual Experience ◽  
Functional Context ◽  
The Relationship

Recent Western preference for functional wooden objects has promoted an ideal of clear, smooth, straight-grained lumber. However, wood does not need to be free of defects to be functional. This paper explores the relationship between decay and functionality in terms of parergonal aesthetics by presenting the use of fungi to alter surface texture and color on wooden bowls. In addition, the bowls' altered but functional state forces the viewer to reconsider modern views on the role of defect-free wood within a functional context.

157. The relationship between optical texture and co2 reactivity of metallurgical coke

Carbon ◽  
1982 ◽  
Vol 20 (2) ◽  
pp. 142
Author(s):  
Seiji Nishida ◽  
Hideo Fujita ◽  
Mitsumasa Hijiriyama
Keyword(s):  
Metallurgical Coke ◽  
Co2 Reactivity ◽  
Optical Texture ◽  
The Relationship
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