scholarly journals CAPACITANCE MEASUREMENTS AND ELECTROSTATIC CALIBRATIONS IN EXPERIMENTS MEASURING THE CASIMIR FORCE

2011 ◽  
Vol 03 ◽  
pp. 527-540 ◽  
Author(s):  
R. S. DECCA ◽  
E. FISCHBACH ◽  
G. L. KLIMCHITSKAYA ◽  
D. E. KRAUSE ◽  
D. LÓPEZ ◽  
...  
Keyword(s):  
Casimir Force ◽  
Spherical Surface ◽  
Scaling Law ◽  
Anomalous Scaling ◽  
Capacitance Measurements ◽  
Spherical Surfaces ◽  
Theoretical Predictions ◽  
Coated Surfaces ◽  
Micrometer Size

We discuss the possibility of determining the properties and quality of spherical surfaces used in precise experiments with the help of capacitance measurements. The results of this kind measurements for the lens-plane and sphere-plane, Au coated surfaces are compared with theoretical predictions from various models of perfect and broken sphericity. It is shown that capacitance measurements are incapable of discriminating between models of perfect and modified centimeter-size spherical surfaces in an experiment demonstrating the anomalous scaling law for the electric force. Claims to the contrary in the recent literature are explained by the use of improper comparison. The data from capacitance measurements in an experiment measuring the Casimir force by means of a micromechanical torsional oscillator employing micrometer-size spheres are shown to be in excellent agreement with theoretical predictions using the model of a perfect spherical surface.

scholarly journals CAPACITANCE MEASUREMENTS AND ELECTROSTATIC CALIBRATIONS IN EXPERIMENTS MEASURING THE CASIMIR FORCE

2011 ◽  
Vol 26 (22) ◽  
pp. 3930-3943 ◽  
Author(s):  
R. S. DECCA ◽  
E. FISCHBACH ◽  
G. L. KLIMCHITSKAYA ◽  
D. E. KRAUSE ◽  
D. LÓPEZ ◽  
...  
Keyword(s):  
Casimir Force ◽  
Spherical Surface ◽  
Scaling Law ◽  
Anomalous Scaling ◽  
Capacitance Measurements ◽  
Spherical Surfaces ◽  
Theoretical Predictions ◽  
Coated Surfaces ◽  
Micrometer Size

We discuss the possibility of determining the properties and quality of spherical surfaces used in precise experiments with the help of capacitance measurements. The results of this kind measurements for the lens-plane and sphere-plane, Au coated surfaces are compared with theoretical predictions from various models of perfect and broken sphericity. It is shown that capacitance measurements are incapable of discriminating between models of perfect and modified centimeter-size spherical surfaces in an experiment demonstrating the anomalous scaling law for the electric force. Claims to the contrary in the recent literature are explained by the use of improper comparison. The data from capacitance measurements in an experiment measuring the Casimir force by means of a micromechanical torsional oscillator employing micrometer-size spheres are shown to be in excellent agreement with theoretical predictions using the model of a perfect spherical surface.

scholarly journals Selection criteria of optimal characteristic material and technologies for precision processing of basic working surface of human hip-joint implant

2018 ◽  
Vol 184 ◽  
pp. 01015 ◽  
Author(s):  
Raul Turmanidze ◽  
Predrag Dašić ◽  
Giorgi Popkhadze
Keyword(s):  
Hip Joint ◽  
Spherical Surface ◽  
Sapphire Crystal ◽  
Spherical Surfaces ◽  
Degree Of Orientation ◽  
Original Scheme ◽  
Definition Of ◽  
Influence Degree ◽  
Selection Of

In view of the fact that the endo-prosthesis heads of human hip-joint are operated in extreme conditions, in respect of load, the selection of corresponding material and also increase of precision and quality of machining of spherical surfaces is rather topical task. In the submitted work are reviewed the problems connected with definition of the influence degree of orientation of the sapphire crystal on its workability during diamond grinding with a butt of the ring and elaboration of the perspective, original scheme of formation of the incomplete spherical surface, particularly, of the sapphire head of endo-prosthesis of the human hip-joint.

scholarly journals Selection Criteria of Optimal Characteristic Material and Technologies for Precision Processing of Basic Working Surface of Human Hip-Joint Implant

2017 ◽  
Vol 261 ◽  
pp. 28-35
Author(s):  
Raul Turmanidze ◽  
Giorgi Popkhadze
Keyword(s):  
Hip Joint ◽  
Spherical Surface ◽  
Sapphire Crystal ◽  
Spherical Surfaces ◽  
Degree Of Orientation ◽  
Original Scheme ◽  
Definition Of ◽  
Influence Degree ◽  
Selection Of

In view of the fact that the endo-prosthesis heads of human hip-joint are operated in extreme conditions, in respect of load, the selection of corresponding material and also increase of precision and quality of machining of spherical surfaces is rather topical task.In the submitted work are reviewed the problems connected with definition of the influence degree of orientation of the sapphire crystal on its workability during diamond grinding with a butt of the ring and elaboration of the perspective, original scheme of formation of the incomplete spherical surface, particularly, of the sapphire head of endo-prosthesis of the human hip-joint.

Testing the link between mergers and AGN in the Arp 245 system

2020 ◽  
Vol 15 (S359) ◽  
pp. 192-194
Author(s):  
Elismar Lösch ◽  
Daniel Ruschel-Dutra
Keyword(s):  
Star Formation ◽  
Active Galactic Nucleus ◽  
Spherical Surface ◽  
Galaxy Mergers ◽  
Nuclear Activity ◽  
Upper Limit ◽  
Spherical Surfaces ◽  
Galactic Centers ◽  
Merger Event ◽  
Major Merger

AbstractGalaxy mergers are known to drive an inflow of gas towards galactic centers, potentia- lly leading to both star formation and nuclear activity. In this work we aim to study how a major merger event in the ARP 245 system is linked with the triggering of an active galactic nucleus (AGN) in the NGC galaxy 2992. We employed three galaxy collision numerical simulations and calculated the inflow of gas through four different concentric spherical surfaces around the galactic centers, estimating an upper limit for the luminosity of an AGN being fed the amount of gas crossing the innermost spherical surface. We found that these simulations predict reasonable gas inflow rates when compared with the observed AGN luminosity in NGC 2992.

Research on Transition Zones of Spherical Surface Parts in 3D Rolling Process

2014 ◽  
Vol 687-691 ◽  
pp. 3-6
Author(s):  
Da Ming Wang ◽  
Ming Zhe Li ◽  
Zhong Yi Cai
Keyword(s):  
Sheet Metal ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Rolling Process ◽  
Experimental Results ◽  
Transition Zones ◽  
Spherical Surfaces ◽  
Sheet Width ◽  
Forming Precision ◽  
Roll Gap

3D rolling is a novel technology for three-dimensional surface parts. In this process, by controlling the gap between the upper and lower forming rolls, the sheet metal is non-uniformly thinned in thickness direction, and the longitudinal elongation of the sheet metal is different along the transverse direction, which makes the sheet metal generate three-dimensional deformation. In this paper, the transition zones of spherical surface parts in 3D rolling process are investigated. Spherical surface parts with the same widths but different lengths are simulated in condition of the same roll gap, and their experimental results are presented. The forming precision of forming parts and the causes of transition zones in the head and tail regions are analyzed through simulated results. The simulated and experimental results show that the lengths of transition zones of spherical surfaces in the head and tail regions are fixed values in condition of the same sheet width and roll gap.

Study of The Tool Path Generation Method of an Ultra-Precision Spherical Complex Surface Based on a Five-Axis Machine Tool

2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun
Keyword(s):  
Surface Roughness ◽  
Tool Path ◽  
Spherical Surface ◽  
Tool Path Generation ◽  
Path Generation ◽  
Tool Paths ◽  
Spherical Surfaces ◽  
Spherical Complex ◽  
Ultra Precision ◽  
Five Axis

Abstract The improvement of ultra-precision machining technology has significantly boosted the demand for the surface quality and surface accuracy of the workpieces to be machined. However, the geometric shapes of workpiece surfaces cannot be adequately manufactured with simple plane, cylindrical, or spherical surfaces because of their different applications in various fields. In this research, a method was proposed to generate tool paths for the machining of complex spherical surfaces based on an ultra-precise five-axis turning and milling machine with a C-Y-Z-X-B structure. Through the proposed tool path generation method, ultra-precise complex spherical surface machining was achieved. First, the complex spherical surface model was modeled and calculated, and then it was combined with the designed model to generate the tool path. Then the tool paths were generated with a numerically controlled (NC) program. Based on an ultra-precision three-coordinate measuring instrument and a white light interferometer, the machining accuracy of a workpiece surface was characterized, and t[1]he effectiveness of the provided tool path generation method was verified. The surface roughness of the machined workpiece was less than 90 nm. Furthermore, the surface roughness within the spherical region appeared to be less than 30 nm. The presented tool path generation method in this research produced ultra-precision spherical complex surfaces. The method could be applied to complex spherical surfaces with other characteristics.

scholarly journals Features selection approaches for an objective control of cosmetic quality of coated surfaces

2020 ◽  
Vol 8 (2) ◽  
pp. 024007
Author(s):  
S Bessonnet ◽  
M El Mansori ◽  
S Mezghani ◽  
N Coniglio ◽  
R Pee ◽  
...  
Keyword(s):  
Features Selection ◽  
Objective Control ◽  
Coated Surfaces

Experimental Investigation of Polymeric Material Removal by Low Diffraction Laser Beam

2002 ◽  
Vol 124 (2) ◽  
pp. 475-480
Author(s):  
Xuanhui Lu ◽  
Y. Lawrence Yao ◽  
Kai Chen
Keyword(s):  
Laser Beam ◽  
Polymeric Material ◽  
Material Removal ◽  
Beam Quality ◽  
Power Level ◽  
Average Power ◽  
Laser Material ◽  
Theoretical Predictions ◽  
Removal Processes

Effects of improved beam quality of a low diffraction laser beam on laser material removal processes are experimentally investigated in a polymeric material. The experimental results are in agreement with theoretical predictions. The results show that the low diffraction beam has marked advantages over the Gaussian beam in ablation-dominated material removal processes in terms of larger depth and smaller taper at the same average power level.

scholarly journals Living Structure Down to Earth and Up to Heaven: Christopher Alexander

Urban Science ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 96 ◽  
Author(s):  
Bin Jiang
Keyword(s):  
Physical Phenomenon ◽  
Scaling Law ◽  
Mathematical Concept ◽  
Daily Lives ◽  
Jane Jacobs ◽  
Christopher Alexander ◽  
The World ◽  
Structural Nature ◽  
Small Things

Discovered by Christopher Alexander, living structure is a physical phenomenon, through which the quality of the built environment or artifacts can be judged objectively. It has two distinguishing properties just like a tree: “Far more small things than large ones” across all scales from the smallest to the largest, and “more or less similar things” on each scale. As a physical phenomenon, and mathematical concept, living structure is essentially empirical, discovered and developed from miniscule observation in nature- and human-made things, and it affects our daily lives in some practical ways, such as where to put a table or a flower vase in a room, helping us to make beautiful things and environments. Living structure is not only empirical, but also philosophical and visionary, enabling us to see the world and space in more meaningful ways. This paper is intended to defend living structure as a physical phenomenon, and a mathematical concept, clarifying some common questions and misgivings surrounding Alexander’s design thoughts, such as the objective or structural nature of beauty, building styles advocated by Alexander, and mysterious nature of his concepts. For this purpose, we first illustrate living structure—essentially organized complexity, as advocated by the late Jane Jacobs (1916–2006)—that is governed by two fundamental laws (scaling law and Tobler’s law), and generated in some step by step fashion by two design principles (differentiation and adaptation) through the 15 structural properties. We then verify why living structure is primarily empirical, drawing evidence from Alexander’s own work, as well as our case studies applied to the Earth’s surface including cities, streets, and buildings, and two logos. Before reaching conclusions, we concentrate on the most mysterious part of Alexander’s work—the luminous ground or the hypothesized “I”—as a substance that pervasively exists everywhere, in space and matter including our bodies, in order to make better sense of living structure in our minds.

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