Assuring Molded Accuracy of Plastic Involute Worm Gears

2007 ◽  
Author(s):  
Michael T. Weiss ◽  
Roderick E. Kleiss
Keyword(s):  
Single Point ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Error Sources ◽  
Analysis Techniques ◽  
Gear Mesh ◽  
Package Size ◽  
Worm Gears ◽  
High Reduction ◽  
Gear Geometry

Many plastic geared transmissions contain crossed-axis worm drives in the first stage. The purpose is usually to achieve high reduction and/or tailored package size. The need for precision control of worm and helical gear geometry is just as important for this gear mesh as for any other. A myriad of molded flaws can degrade or destroy the performance of these gears. Pitch, tooth thickness, and lead errors are only a few possibilities. Barrel shaped, tapered, or hourglass bodies must be identified and controlled. Asymmetrical teeth are a distinct possibility as well. The only proper way to detect and evaluate these conditions is to scan and analyze these gears in three dimensions. The traditional method of scanning only one section of the tooth on a worm and then scanning the lead at the pitch line will not reveal many molded gear error sources. Measuring pitch or tooth thickness by taking single point measurements around the gear will also miss many errors. We have developed scanning and analysis techniques to accurately map the size and accuracy of these truly three-dimensional involute gear shapes.

scholarly journals 3D Magnetic Reconnection

2010 ◽  
Vol 6 (S271) ◽  
pp. 227-238 ◽  
Author(s):  
Clare E. Parnell ◽  
Rhona C. Maclean ◽  
Andrew L. Haynes ◽  
Klaus Galsgaard
Keyword(s):  
Magnetic Reconnection ◽  
Energy State ◽  
Single Point ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Wide Range ◽  
Field Lines ◽  
Magnetohydrodynamic Models ◽  
The Magnetic Field

AbstractMagnetic reconnection is an important process that is prevalent in a wide range of astrophysical bodies. It is the mechanism that permits magnetic fields to relax to a lower energy state through the global restructuring of the magnetic field and is thus associated with a range of dynamic phenomena such as solar flares and CMEs. The characteristics of three-dimensional reconnection are reviewed revealing how much more diverse it is than reconnection in two dimensions. For instance, three-dimensional reconnection can occur both in the vicinity of null points, as well as in the absence of them. It occurs continuously and continually throughout a diffusion volume, as opposed to at a single point, as it does in two dimensions. This means that in three-dimensions field lines do not reconnect in pairs of lines making the visualisation and interpretation of three-dimensional reconnection difficult.By considering particular numerical 3D magnetohydrodynamic models of reconnection, we consider how magnetic reconnection can lead to complex magnetic topologies and current sheet formation. Indeed, it has been found that even simple interactions, such as the emergence of a flux tube, can naturally give rise to ‘turbulent-like’ reconnection regions.

scholarly journals Implementation of a High-Throughput Pilot Screen in Peptide Hydrogel-Based Three-Dimensional Cell Cultures

2019 ◽  
Vol 24 (7) ◽  
pp. 714-723 ◽  
Author(s):  
Peter Worthington ◽  
Katherine M. Drake ◽  
Zhiqin Li ◽  
Andrew D. Napper ◽  
Darrin J. Pochan ◽  
...  
Keyword(s):  
High Throughput ◽  
Single Point ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Culture Cells ◽  
High Throughput Drug Screening ◽  
Cell Culture Systems ◽  
Starting Point ◽  
Pediatric Brain ◽  
Dimensional Cell

Cell-based high-throughput drug screening (HTS) is a common starting point for the drug discovery and development process. Currently, there is a push to combine complex cell culture systems with HTS to provide more clinically applicable results. However, there are mechanistic requirements inherent to HTS as well as material limitations that make this integration challenging. Here, we used the peptide-based shear-thinning hydrogel MAX8 tagged with the RGDS sequence to create a synthetic extracellular scaffold to culture cells in three dimensions and showed a preliminary implementation of the scaffold within an automated HTS setup using a pilot drug screen targeting medulloblastoma, a pediatric brain cancer. A total of 2202 compounds were screened in the 384-well format against cells encapsulated in the hydrogel as well as cells growing on traditional two-dimensional (2D) plastic. Eighty-two compounds passed the first round of screening at a single point of concentration. Sixteen-point dose–response was done on those 82 compounds, of which 17 compounds were validated. Three-dimensional (3D) cell-based HTS could be a powerful screening tool that allows researchers to finely tune the cell microenvironment, getting more clinically applicable data as a result. Here, we have shown the successful integration of a peptide-based hydrogel into the high-throughput format.

Three Dimensional Vibration Measurements Using a Five-Axis Scanning Laser Vibrometry System

2007 ◽  
Author(s):  
Patrick F. O’Malley ◽  
John A. Judge ◽  
Joseph F. Vignola
Keyword(s):  
Single Point ◽  
Three Dimensional ◽  
Laser Doppler Vibrometer ◽  
Three Dimensions ◽  
Surface Velocity ◽  
Experimental Facility ◽  
Laser Vibrometry ◽  
Data Set ◽  
Single Beam ◽  
Five Axis

This paper describes an experimental facility designed to measure three-dimensional velocity components using a five-axis laser vibrometry system. A single-point laser Doppler vibrometer (LDV) is mounted on three orthogonal translation stages, and the beam is directed to the target specimen by means of a mirror mounted at the intersection of the axes of two rotational stages. The result is a system with which the vibration of points on the surface of the test specimen can be measured from multiple angles, and these multiple measured components of the surface velocity are combined to determine the full velocity vector in three-dimensions. This system allows collection of a richer data set for more detailed vibration analysis, measurement of vibration of non-planar surfaces, and greater control over measurements compared to conventional single-beam scanning LDV, while greatly reducing experimental facility costs compared with threedimensional LDV systems that use multiple lasers.

Sub-Diffraction Limit Three Dimensional Particle Tracking Velocimetry

2013 ◽  
Author(s):  
Craig A. Snoeyink ◽  
Gordon Christopher ◽  
Sourav Barman ◽  
Steve Wereley
Keyword(s):  
Imaging System ◽  
Optical Measurement ◽  
Single Point ◽  
Bessel Beam ◽  
Three Dimensional ◽  
Diffraction Limit ◽  
Point Of View ◽  
Three Dimensions ◽  
Three Dimension ◽  
Single View

Here we present an optical measurement technique and image analysis process capable of tracking particles in three dimensions with a single point of view. In addition to single view 3D-PTV, the optical system is capable of tracking individual particles even at particle-particle spacings that are closer then the diffraction limit of the base imaging system. The measurement system, termed Bessel Beam Microscopy (BBM), functions as an attachment for a microscope that fits between the microscope base and camera. The addition of the BBM attachment transforms the point spread function (PSF) of the microscope allowing two unique functions: single image superresolution imaging, and the extraction of three dimension location information of particles without calibration. The result is a fluid characterization tool with unique capabilities for velocimetry and characterization of the dynamics of dense fluid-particle suspensions.

scholarly journals Multipoint observations of plasma phenomena made in space by Cluster

2015 ◽  
Vol 81 (3) ◽  
Author(s):  
M. L. Goldstein ◽  
P. Escoubet ◽  
K.-Joo Hwang ◽  
D. E. Wendel ◽  
A.-F. Viñas ◽  
...  
Keyword(s):  
Electric Fields ◽  
Single Point ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Full Description ◽  
Interstellar Space ◽  
Cluster Data ◽  
Magnetospheric Multiscale Mission ◽  
Using Data ◽  
The Many

Plasmas are ubiquitous in nature, surround our local geospace environment, and permeate the universe. Plasma phenomena in space give rise to energetic particles, theaurora, solar flares and coronal mass ejections, as well as many energetic phenomena in interstellar space. Although plasmas can be studied in laboratory settings, it is often difficult, if not impossible, to replicate the conditions (density, temperature, magnetic and electric fields, etc.) of space. Single-point space missions too numerous to list have described many properties of near-Earth and heliospheric plasmas as measured bothin situand remotely (seehttp://www.nasa.gov/missions/#.U1mcVmeweRYfor a list of NASA-related missions). However, a full description of our plasma environment requires three-dimensional spatial measurements. Cluster is the first, and until data begin flowing from the Magnetospheric Multiscale Mission (MMS), the only mission designed to describe the three-dimensional spatial structure of plasma phenomena in geospace. In this paper, we concentrate on some of the many plasma phenomena that have been studied using data from Cluster. To date, there have been more than 2000 refereed papers published using Cluster data but in this paper we will, of necessity, refer to only a small fraction of the published work. We have focused on a few basic plasma phenomena, but, for example, have not dealt with most of the vast body of work describing dynamical phenomena in Earth's magnetosphere, including the dynamics of current sheets in Earth's magnetotail and the morphology of the dayside high latitude cusp. Several review articles and special publications are available that describe aspects of that research in detail and interested readers are referred to them (see for example, Escoubet et al. 2005Multiscale Coupling of Sun-Earth Processes, p. 459, Keith et al. 2005Sur. Geophys.26, 307–339, Paschmann et al. 2005Outer Magnetospheric Boundaries: Cluster Results, Space Sciences Series of ISSI. Berlin: Springer, Goldstein et al. 2006Adv. Space Res.38, 21–36, Taylor et al. 2010The Cluster Mission: Space Plasma in Three Dimensions, Springer, pp. 309–330 and Escoubet et al. 2013Ann. Geophys.31, 1045–1059).

convergent-beam diffraction from surfaces

1987 ◽  
Vol 45 ◽  
pp. 30-33
Author(s):  
J. A. Eades ◽  
A. E. Smith ◽  
D. F. Lynch
Keyword(s):  
Reciprocal Lattice ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
Three Dimensions ◽  
Plane Figure ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Beam Patterns ◽  
Beam Diffraction

It is quite simple (in the transmission electron microscope) to obtain convergent-beam patterns from the surface of a bulk crystal. The beam is focussed onto the surface at near grazing incidence (figure 1) and if the surface is flat the appropriate pattern is obtained in the diffraction plane (figure 2). Such patterns are potentially valuable for the characterization of surfaces just as normal convergent-beam patterns are valuable for the characterization of crystals.There are, however, several important ways in which reflection diffraction from surfaces differs from the more familiar electron diffraction in transmission.GeometryIn reflection diffraction, because of the surface, it is not possible to describe the specimen as periodic in three dimensions, nor is it possible to associate diffraction with a conventional three-dimensional reciprocal lattice.

Extension of the Spatial PDI Model to Three Dimensions

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien
Keyword(s):  
Population Density ◽  
Dimensional Space ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Upper Bounds ◽  
Three Dimensions ◽  
Lower And Upper Bounds ◽  
Density Index ◽  
Three Dimensional Space

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.

scholarly journals Free partition functions and an averaged holographic duality

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Nima Afkhami-Jeddi ◽  
Henry Cohn ◽  
Thomas Hartman ◽  
Amirhossein Tajdini
Keyword(s):  
Partition Function ◽  
Spectral Gap ◽  
Central Charge ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Partition Functions ◽  
General Constraints ◽  
Dimensional Gravity ◽  
Holographic Duality

Abstract We study the torus partition functions of free bosonic CFTs in two dimensions. Integrating over Narain moduli defines an ensemble-averaged free CFT. We calculate the averaged partition function and show that it can be reinterpreted as a sum over topologies in three dimensions. This result leads us to conjecture that an averaged free CFT in two dimensions is holographically dual to an exotic theory of three-dimensional gravity with U(1)c×U(1)c symmetry and a composite boundary graviton. Additionally, for small central charge c, we obtain general constraints on the spectral gap of free CFTs using the spinning modular bootstrap, construct examples of Narain compactifications with a large gap, and find an analytic bootstrap functional corresponding to a single self-dual boson.

Turbulent three-dimensional dielectric electrohydrodynamic convection between two plates

2012 ◽  
Vol 696 ◽  
pp. 228-262 ◽  
Author(s):  
A. Kourmatzis ◽  
J. S. Shrimpton
Keyword(s):  
Spatial Data ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Energy Budgets ◽  
Turbulent Regime ◽  
Scalar Flux ◽  
Wide Range ◽  
Scalar Variance

AbstractThe fundamental mechanisms responsible for the creation of electrohydrodynamically driven roll structures in free electroconvection between two plates are analysed with reference to traditional Rayleigh–Bénard convection (RBC). Previously available knowledge limited to two dimensions is extended to three-dimensions, and a wide range of electric Reynolds numbers is analysed, extending into a fully inherently three-dimensional turbulent regime. Results reveal that structures appearing in three-dimensional electrohydrodynamics (EHD) are similar to those observed for RBC, and while two-dimensional EHD results bear some similarities with the three-dimensional results there are distinct differences. Analysis of two-point correlations and integral length scales show that full three-dimensional electroconvection is more chaotic than in two dimensions and this is also noted by qualitatively observing the roll structures that arise for both low (${\mathit{Re}}_{E} = 1$) and high electric Reynolds numbers (up to ${\mathit{Re}}_{E} = 120$). Furthermore, calculations of mean profiles and second-order moments along with energy budgets and spectra have examined the validity of neglecting the fluctuating electric field ${ E}_{i}^{\ensuremath{\prime} } $ in the Reynolds-averaged EHD equations and provide insight into the generation and transport mechanisms of turbulent EHD. Spectral and spatial data clearly indicate how fluctuating energy is transferred from electrical to hydrodynamic forms, on moving through the domain away from the charging electrode. It is shown that ${ E}_{i}^{\ensuremath{\prime} } $ is not negligible close to the walls and terms acting as sources and sinks in the turbulent kinetic energy, turbulent scalar flux and turbulent scalar variance equations are examined. Profiles of hydrodynamic terms in the budgets resemble those in the literature for RBC; however there are terms specific to EHD that are significant, indicating that the transfer of energy in EHD is also attributed to further electrodynamic terms and a strong coupling exists between the charge flux and variance, due to the ionic drift term.

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