scholarly journals Experimental setup proposed to measure the quality of a spherical surface using deflectometry and a Hartmann screen

2015 ◽  
Vol 605 ◽  
pp. 012004 ◽  
Author(s):  
A Muñoz-Potosi ◽  
R Díaz-Uribe ◽  
M Campos-García ◽  
F Granados-Agustín
Keyword(s):  
Spherical Surface ◽  
Experimental Setup

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.

Quality assurance for concave-arc ball-end milling cutters

2003 ◽  
Vol 217 (2) ◽  
pp. 181-191 ◽  
Author(s):  
W-F Chen ◽  
H-Y Lai ◽  
C-K Chen
Keyword(s):  
End Milling ◽  
Spherical Surface ◽  
Numerical Control ◽  
Machining Accuracy ◽  
Milling Cutter ◽  
Modelling Procedure ◽  
Profile Errors ◽  
Complicated Surface ◽  
Dies And Moulds

This paper presents a systematic modelling procedure for assessing the profile quality of concave-arc ball-end (CABE) milling cutters with a cylindrical shank. CABE milling cutters are widely used in three-axis numerical control (NC) machines for producing dies and moulds of complicated surface features. Evaluation of the contour quality of the CABE milling cutter is crucial in enhancing machining accuracy and efficiency. In order adequately to describe the shape of the clamped cutter, the centre-line axis of the minimum circumscribed cylinder of the cylinder shank is taken as the referenced datum axis. The minimum circumscribed concave-arc revolving surface and the minimum circumscribed spherical surface are carefully derived in sequence. The profile errors and tolerances are estimated. The quality of the CABE milling cutter is assured by using the proposed modelling procedure, and several numerical examples are presented to illustrate its effectiveness. The results indicate that the present method is feasible and can be extended to enhance the quality of various revolving cutters.

scholarly journals Development and characterisation of a self-powered measurement buoy prototype by means of piezoelectric energy harvester for monitoring activities in a marine environment

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 201
Author(s):  
Damiano Alizzio ◽  
Antonino Quattrocchi ◽  
Roberto Montanini
Keyword(s):  
Resonant Frequency ◽  
Environmental Monitoring ◽  
Power Supply ◽  
Smart City ◽  
Energy Harvester ◽  
Experimental Setup ◽  
Piezoelectric Energy ◽  
Maintenance Service ◽  
Self Powered

<p class="Abstract">In the interest of our society, for example in Smart City but also in other specific backgrounds, environmental monitoring is an essential activity to measure the quality of different ecosystems. In fact, the need to obtain accurate and extended measurements in space and time has considerably become relevant. In very large environments, such as marine ones, technological solutions are required for the use of smart, automatic, and self-powered devices in order to reduce human maintenance service. This work presents a simple and innovative layout for a small self-powered floating buoy, with the aim of measuring and transmitting the detected data for visualization, storage and/or elaboration. The power supply was obtained using a cantilever harvester, based on piezoelectric patches, converting the motion of ripple waves. Such type of waves is characterized by frequencies between 1.50 Hz and 2.50 Hz with oscillation between 5.0 ° and 7.0 °. Specifically, a dedicated experimental setup was created to simulate the motion of ripple waves and to evaluate the suitability of the proposed design and the performance of the used harvester. Furthermore, a dynamic analytical model for the harvester has been defined and the uncertainty correlated to the harvested power has been evaluated. Finally, the harvested voltage and power have shown how the presented buoy behaves like a frequency transformer. Hence, although the used cantilever harvester does not work in its resonant frequency, the harvested electricity undergoes a significant increase.</p><p class="Abstract"><span lang="EN-US"><br /></span></p>

Laser Logic State Imaging Using Transient Voltage Collapse Circuits

2015 ◽  
Author(s):  
Gwanghyeon Baek ◽  
John Keane ◽  
Martin von Haartman
Keyword(s):  
Image Quality ◽  
Experimental Setup ◽  
Voltage Collapse ◽  
Logic State ◽  
Transient Voltage

Abstract A laser based logic state imaging (LLSI) by activating transient voltage collapse (TVC) circuits of SRAM blocks is demonstrated. In order to induce a voltage modulation on a power rail, significant numbers of TVC units are activated. The image quality of LLSI strongly depends on a number of activated TVC circuits. From this experiment, it is concluded that an additional circuit or experimental setup is not necessary for LLSI.

scholarly journals Improvement of a Stitching Operation in the Stitching Linear-Scan Method for Measurement of Cylinders in a Small Dimension

2021 ◽  
Vol 11 (10) ◽  
pp. 4705
Author(s):  
Qiaolin Li ◽  
Yuki Shimizu ◽  
Toshiki Saito ◽  
Hiraku Matsukuma ◽  
Yindi Cai ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Axial Direction ◽  
Small Dimension ◽  
Scanning Probe ◽  
Experimental Setup ◽  
Edge Region ◽  
Roundness Measurement ◽  
Stylus Profiler ◽  
Made In

Attempts are made in this paper to improve the quality of the stitching between adjacent arc-profiles in the stitching linear-scan method for the roundness measurement of a cylinder in a small dimension. The data in the edge region of an arc-profile, which could be influenced by the pressure angle of the measurement probe of a linear-scan stylus profiler, are eliminated in the stitching process to improve the quality of stitching. The effectiveness of the elimination of the edge region of an arc-profile is evaluated by employing the cross-correlation coefficient of two adjacent arc-profiles as an evaluation index. Furthermore, a modification is made to the experimental setup to reduce the misalignment of a workpiece along its axial direction with respect to the scanning probe. Experiments are carried out by using the modified setup to demonstrate the feasibility of the stitching linear-scan method for the roundness measurement of a small cylinder, which is difficult to measure by the conventional rotary-scan method.

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 EVALUATION OF THE QUALITY OF ACTION CAMERAS WITH WIDE-ANGLE LENSES IN UAV PHOTOGRAMMETRY

2016 ◽  
Vol XLI-B1 ◽  
pp. 851-859 ◽  
Author(s):  
H. Hastedt ◽  
T. Ekkel ◽  
T. Luhmann
Keyword(s):  
Eye Lens ◽  
Experimental Setup ◽  
Light Weight ◽  
Wide Angle ◽  
Control Points ◽  
Wide Angle Lens ◽  
Standard Calibration ◽  
Normal Lens ◽  
Fish Eye

The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

Wavefront Reconstruction Using Two In-Line Holograms

2013 ◽  
Vol 718-720 ◽  
pp. 1324-1328
Author(s):  
Lu Rong ◽  
Da Yong Wang
Keyword(s):  
Rate Of Convergence ◽  
Iterative Reconstruction ◽  
Phase Retrieval ◽  
Experimental Setup ◽  
Reconstruction Method ◽  
Rapid Rate ◽  
Wavefront Reconstruction ◽  
Reconstruction Quality ◽  
Fast Dynamic

The reconstruction quality of in-line holography suffers from the superposition of twin images, which blurs the details and degrades the quality of the object wavefront reconstruction. We present an iterative reconstruction method to eliminate twin image and truthfully retrieve the object wavefront. This algorithm has a better elimination effect and more rapid rate of convergence than other phase retrieval methods. An experimental setup was built with dual cameras recording the holograms simultaneously, thus this technique can be employed for investigating fast dynamic phenomina. The effectiveness of the proposed method is validated using different samples.

scholarly journals EVALUATION OF THE QUALITY OF ACTION CAMERAS WITH WIDE-ANGLE LENSES IN UAV PHOTOGRAMMETRY

2016 ◽  
Vol XLI-B1 ◽  
pp. 851-859 ◽  
Author(s):  
H. Hastedt ◽  
T. Ekkel ◽  
T. Luhmann
Keyword(s):  
Eye Lens ◽  
Experimental Setup ◽  
Light Weight ◽  
Wide Angle ◽  
Control Points ◽  
Wide Angle Lens ◽  
Standard Calibration ◽  
Normal Lens ◽  
Fish Eye

The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

scholarly journals Wind inflow observation from load harmonics: initial steps towards a field validation

2020 ◽  
Author(s):  
Marta Bertelè ◽  
Carlo L. Bottasso ◽  
Johannes Schreiber
Keyword(s):  
Independent Method ◽  
Experimental Setup ◽  
Reasonable Accuracy ◽  
Field Validation ◽  
Turbulent Fluctuations ◽  
Air Density ◽  
Time Histories ◽  
Rotor Disk ◽  
Practical Demonstration

Abstract. A previously published wind sensing method is applied to an experimental dataset obtained on a 3.5 MW turbine and a nearby hub-tall met-mast. The method uses blade load harmonics to estimate rotor-equivalent shears and wind directions at the rotor disk. A second independent method is used to extend the met-mast-measured shear above hub height to cover the entire rotor disk. Although the experimental setup falls short of providing a real validation of the method, it still allows for a realistic practical demonstration of some of its main features. The method appears to be robust to turbulent fluctuations and air density changes. Results indicate a good quality of the estimated shear, both in terms of 10-min averages and of resolved time histories, and a reasonable accuracy in the estimation of the yaw misalignment.

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