Consecutive observations of the relationship between eroded contact surfaces and motion of breaking arc at each breaking operation

2005 ◽  
Author(s):  
J. Sekikawa ◽  
T. Kubono
Keyword(s):  
Contact Surfaces ◽  
The Relationship

Robotic Peg-Hole Insertion Operations using a Six-Component Force Sensor

1993 ◽  
Vol 207 (5) ◽  
pp. 289-306 ◽  
Author(s):  
H Qiao ◽  
B S Dalay ◽  
R M Parkin
Keyword(s):  
Initial Conditions ◽  
Industrial Robot ◽  
Force Sensor ◽  
Force Sensors ◽  
Geometric Uncertainties ◽  
Two Measures ◽  
Contact Surfaces ◽  
Novel Strategy ◽  
The Relationship ◽  
Component Force

Peg-hole insertion is a widely used industrial robot process. For precise insertion it is common to use force sensors to obtain the deviation between the peg and the hole. In this paper, several examples of six-component force sensors, which are designed to measure the forces and torques in all directions, are reviewed. The problem of how to obtain the deviation between the peg and the hole from the measurement of the forces and the torques exerted on the sensors is then discussed. It is shown that the angle between the peg and the hole and the roughness of the contact surfaces (the end surface of the peg and the surface surrounding the hole) would significantly influence the identification of deviation, no matter how small they are. Two measures to address these phenomena are introduced. A novel strategy of the high-precision chamferless peg-hole insertion with a wrist force sensor is presented and verified experimentally. This strategy is constructed: to obtain the relationship between the peg and hole from the force sensor signal when angular misalignment and the defects of the contact surfaces are present to reduce the angular and lateral errors and to achieve precise chamferless robotic peg-hole insertion. In this paper, it is shown that the insertion can be effected with a reasonably large range of initial conditions. The principle is to move and rotate the peg from an area having many geometric uncertainties to a new area, where the deviation of the peg and hole can be obtained.

Relationship between Listeria monocytogenes and Listeria spp. in Seafood Processing Plants

2013 ◽  
Vol 76 (7) ◽  
pp. 1279-1282 ◽  
Author(s):  
WALID Q. ALALI ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Listeria Monocytogenes ◽  
Raw Materials ◽  
Food Products ◽  
Published Data ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Processing Plants ◽  
Contact Surfaces ◽  
Seafood Processing ◽  
The Relationship

The objective of this study was to evaluate the relationship between prevalence of Listeria monocytogenes as an outcome and Listeria spp. as an explanatory variable by food products, food contact surfaces, and nonfood contact surfaces in seafood processing plants by using peer-reviewed published data. Nine sets of prevalence data of L. monocytogenes and Listeria spp. were collected from published studies and used for the analyses. Based on our analysis, the relationship between L. monocytogenes prevalence and Listeria spp. prevalence in food products (incoming raw materials and finish products) was significant (P = 0.04) with (low) R2 = 0.36. Furthermore, Listeria spp. were not a good indicator for L. monocytogenes when testing food contact surfaces (R2= 0.10). Listeria spp. were a good indicator for L. monocytogenes only on nonfood contact surfaces (R2= 0.90). On the other hand, the presence of Listeria spp. on food contact surfaces (R2= 0.002) and nonfood contact surfaces (R2= 0.03) was not a good indicator for L. monocytogenes presence in food products. In general, prevalence of Listeria spp. does not seem to be a good indicator for L. monocytogenes prevalence in seafood processing plants.

scholarly journals The Effects of Shear Stress on the Lubrication Performances of Oil Film of Large-Scale Mill Bearing

2009 ◽  
Vol 76-78 ◽  
pp. 713-718
Author(s):  
Jian Mei Wang ◽  
Qing Xue Huang ◽  
Zheng Yi Jiang ◽  
Kiet Tieu
Keyword(s):  
Shear Stress ◽  
Large Scale ◽  
Film Flow ◽  
Lubricating Oil ◽  
Oil Film ◽  
Lubrication Performance ◽  
Shear Performance ◽  
Contact Surfaces ◽  
The Relationship ◽  
Bearing System

A new coupling numerical algorithm has been developed to integrate Finite Difference Method (FDM) with Boundary Element Method (BEM) to analyze shear performance of oil film by iteratively solving a series of equations such as the film flow velocity and shear stress equations for contact bodies in bearing system. With consideration of the variations of viscosity and density with pressure and temperature, the effects of shear stress of oil film layers on lubrication performance of contact surfaces under different loadcases were discussed. Moreover, Germany-made Anton Paar MRD (Magnetic Rheologic Device) was used to determine the relationship between the viscosity and shear stress of lubricating oil. The conclusions were verified to be beneficial to the further study on lubricating performance of heavy contact components and to prolong their service lives.

A Simple Model of the Entrainment of Particles in a Gap Considering Elasticity

2008 ◽  
Author(s):  
Zhenyuan Zhong ◽  
Youyun Zhang ◽  
Haiyan Han
Keyword(s):  
Friction And Wear ◽  
Plane Surface ◽  
Sliding Surface ◽  
Dimensional Model ◽  
Sliding Surfaces ◽  
Contact Surfaces ◽  
Entrainment Of Particles ◽  
Lubricated Contact ◽  
Relationship Of ◽  
The Relationship

Many researches are conducted on the effect of particles on lubricated friction and wear of contact surfaces, which shows that particles between two contact surfaces increase lubricated friction and do a great effect to the wear of two sliding surfaces. Similar phenomena also occur when a hard containment particle is being entrained into the lubricated contact. This paper presents a simple two dimensional model which describes the entrainment of particles in a gap. Considering elasticity of the sliding surfaces, the model treats conditions under which a spherical particle of size d can be entrained into a gap between a sliding surface and a fixed plane surface. These conditions are determined by size of the particles, d, and friction coefficients between the particle and the sliding surface, and the particle and the plane, denoted by μs and μp respectively. For the particles to be entrained into the contact, this model predicts the maximum of particles size and the relationship of μs and μp.

A New Method Developed for Fractal Dimension and Topothesy Varying With the Mean Separation of Two Contact Surfaces

2006 ◽  
Vol 128 (3) ◽  
pp. 515-524 ◽  
Author(s):  
Jeng Luen Liou ◽  
Jen Fin Lin
Keyword(s):  
Fractal Dimension ◽  
Power Spectrum ◽  
Contact Spot ◽  
Experimental Results ◽  
Spot Number ◽  
Spectrum Function ◽  
The Mean ◽  
Contact Surfaces ◽  
The Relationship ◽  
Scaling Coefficient

Instead of a general consideration of the fractal dimension (D) and the topothesy (G*) as two invariants in the fractal analysis of surface asperities, these two roughness parameters in the present study are varied by changing the mean separation (d*) of two contact surfaces. The relationship between the fractal dimension and the mean separation is found first. By equating the structure functions developed in two different ways, the relationship among the scaling coefficient in the power spectrum function, the fractal dimension, and topothesy of asperity heights can be established. The variation of topothesy can be determined when the fractal dimension and the scaling coefficient have been obtained from the experimental results of the number of contact spots and the power spectrum function at different mean separations. A numerical scheme is developed in this study to determine the convergent values of fractal dimension and topothesy corresponding to a given mean separation. The theoretical results of the contact spot number predicted by the present model show good agreement with the reported experimental results. Both the fractal dimension and the topothesy are elevated by increasing the mean separation. Significant differences in the contact load or the total contact area are shown between the models of constant D and G* and variable D and G* as the mean separation is reduced to smaller values.

scholarly journals Developing Smart Measurement Device to Measure Kinetic Friction Coefficients of Bi-Tilt Isolator

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ming-Hsiang Shih ◽  
Wen-Pei Sung
Keyword(s):  
Friction Coefficient ◽  
Image Correlation ◽  
Kinetic Friction ◽  
Measurement Device ◽  
Friction Coefficients ◽  
Measuring Device ◽  
Contact Surfaces ◽  
Relationship Of ◽  
The Relationship ◽  
Smart Measurement

A sliding vibration isolation system, affected by a kinetic friction force, provides a flexible or energy dissipation system for a structure. The kinetic friction coefficient of the contact surfaces between the moving parts changes with the relative moving velocity of the two contact surfaces. In this study, a smart measuring device is proposed to measure the kinetic friction coefficients of materials. The Arduino boards Arduino Nano, Arduino MPU-9250, and Arduino SD modules were combined to create this proposed smart device and mounted on three aluminum extrusions constructed as a horizontal platform. Then, varying amounts of steel gaskets were applied to adjust the various slopes for sliding tests. The time history of the acceleration and displacement responses of test object movements in the sliding process were respectively, recorded and detected by this proposed smart measuring device and the digital image correlation method (DIC). Statistical analyses of all test responses were used to derive the relationship of velocity to kinetic friction coefficient. Test and analysis results showed that (1) the relationship of velocity to kinetic friction coefficient for the conditions of mild lubrication and no lubrication displayed a trend of first decreasing and then increasing with increasing speed, respectively and (2) the relationship of velocity to kinetic friction coefficient for the condition of full lubrication revealed that the kinetic friction coefficient decreased with increasing speed. Test results demonstrated that this proposed smart measurement device, which is low in price and easy to assemble, can easily measure the kinetic friction coefficient of a material under various lubrication conditions.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Tinkering with cognitive gadgets: Cultural evolutionary psychology meets active inference

2019 ◽  
Vol 42 ◽  
Author(s):  
Paul Benjamin Badcock ◽  
Axel Constant ◽  
Maxwell James Désormeau Ramstead
Keyword(s):  
Evolutionary Psychology ◽  
Research Program ◽  
Active Inference ◽  
Innovative Research ◽  
Cognitive Faculties ◽  
Cultural Evolutionary ◽  
The Relationship

Abstract Cognitive Gadgets offers a new, convincing perspective on the origins of our distinctive cognitive faculties, coupled with a clear, innovative research program. Although we broadly endorse Heyes’ ideas, we raise some concerns about her characterisation of evolutionary psychology and the relationship between biology and culture, before discussing the potential fruits of examining cognitive gadgets through the lens of active inference.

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