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University of Cincinnati

1. Ramaswami, Hemant. A Novel Method for Accurate Evaluation of Size for Cylindrical Components.

Degree: MS, Engineering : Mechanical Engineering, 2010, University of Cincinnati

URL: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1267548284

The objective of this thesis is to develop a
methodology to calculate the size of a cylindrical profile
accurately per ANSI standards. The ANSI Y 14.5.1M-1994 standard
defines the size of a cylinder as the size of the largest ball
rolling on a spine such that all points on the surface of the
cylinder are external to it, or the size of the smallest ball
rolling on a spine such that all points on the surface of the
cylinder are internal to it. Current methods of
size evaluation reduce the complexity of the spine and model it as
a straight line. A novel methodology to evaluate the control points
of the spine modeled as a Bezier curve or an Open Uniform B-Spline
curve of a pre-specified degree based on points collected on the
surface of the cylinder has been developed in this thesis. This
provides a quantitative measure of the size of the cylinder in
accordance with ANSI standards. The formulations to evaluate the
maximum inscribing spine and the minimum circumscribing spine are
presented as multi-level optimization problems. The outer level
optimization is used to identify the optimal set of control points
for the spline representing the path of the rolling ball. The inner
level optimization is used to find the nearest point on the curve
corresponding to every point in the dataset. The
optimization formulation has been used to calculate the true size
of cylinders for several published, simulated and real datasets.
These results have been compared to traditional estimates for size
of a cylinder, such as the maximum inscribed, minimum circumscribed
and least squares cylinders. The results indicate that the method
presented in this research conforms better to the ANSI standards as
compared to the traditional methods. Further analysis is presented
to observe the effect of sample size on the results of the
algorithm. It is observed that with an increase in the sample size,
the difference between the results of the presented algorithm and
the traditional methods increases with the presented method
providing more accurate estimates of the size of the
cylinder.
*Advisors/Committee Members: Anand, Sundararaman (Committee Chair).*

Subjects/Keywords: Mechanical Engineering; Size of a Cylinder; Actual Value; Open Uniform B-Spline Curve; B&233; zier Curve; Particle Swarm Optimization

Record Details Similar Records

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^{th} Edition):

Ramaswami, H. (2010). A Novel Method for Accurate Evaluation of Size for Cylindrical Components. (Masters Thesis). University of Cincinnati. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=ucin1267548284

Chicago Manual of Style (16^{th} Edition):

Ramaswami, Hemant. “A Novel Method for Accurate Evaluation of Size for Cylindrical Components.” 2010. Masters Thesis, University of Cincinnati. Accessed October 24, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1267548284.

MLA Handbook (7^{th} Edition):

Ramaswami, Hemant. “A Novel Method for Accurate Evaluation of Size for Cylindrical Components.” 2010. Web. 24 Oct 2020.

Vancouver:

Ramaswami H. A Novel Method for Accurate Evaluation of Size for Cylindrical Components. [Internet] [Masters thesis]. University of Cincinnati; 2010. [cited 2020 Oct 24]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1267548284.

Council of Science Editors:

Ramaswami H. A Novel Method for Accurate Evaluation of Size for Cylindrical Components. [Masters Thesis]. University of Cincinnati; 2010. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1267548284

2. Gupta, Aman. Ultra-High Field MR Diffusion Tensor Imaging Characterization of Rabbit Tendons and Ligaments.

Degree: 2012, University of Illinois – Chicago

URL: http://hdl.handle.net/10027/9137

Tendons and ligaments are dense, fibrous connective tissues that
facilitate transmission of loads from muscle to bone (tendon) or from
bone to bone (ligament). These tissues are subjected to wear and tear
from day-to-day mechanical usage leading to sprains, tendinopathies,
or ruptures, each of which is a major source of musculoskeletal
disability. Clinically, the diagnosis of tendon and ligament injury is
based on a clinical examination as well as magnetic resonance imaging
(MRI) of the relevant tissues. MRI is a reliable, non-invasive tool
for detecting large and complete tears; however, conventional T1 and
T2-weighted grayscale images exhibit poor contrast and a low
signal-to-noise ratio which makes identification of low-grade injuries
more challenging to delineate. Therefore, there exists a need for
reliable, quantitative and more robust imaging approaches to assess
tendon and ligament microstructure and integrity.
One of these MR approaches is diffusion tensor imaging (DTI), an
advanced MRI technique primarily used in neuroimaging applications.
DTI assesses tissue microstructural organization by quantifying the 3D
diffusion of water molecules within tissues. It relies on the basic
diffusion principle that water molecules diffuse more readily along
(i.e., parallel to), rather than across physical barriers (e.g.,
collagen fibers). Diffusion of water molecules can be quantified by
the diffusion tensor in each voxel, whereby the magnitude and
orientation of water diffusion can be computed throughout the tissue,
thus revealing the fiber microstructure. The primary aims of the
proposed studies are to demonstrate applicability and reliability of
the DTI technique for tendons and ligaments, and determine the
sensitivity of b-values to DTI derived parameters of tissue integrity.
This is the first study to show feasibility and applicability of DTI
on Tendons and Ligaments at ultra-high magnetic fields with high
resolutions and measure DTI metrics from both tissue types. High
Fractional Anisotropy values of 0.67 for semitendinosus tendons and
0.66 for medial collateral ligaments shows the highly anisotropic
nature of these soft connective tissues.Axial diffusivity is about 3
times the radial diffusivity which shows diffusion directional
anisotropy indicating diffusion preference along the fibers then
across them. The present study showed fiber tractography of these
tissues at ultra-high magnetic fields with a histological correlation
confirming the highly-organized parallel collagen fiber
microstructure. Diffusion tensor imaging is sensitive to the
diffusional anisotropy differences and can show microstructural
differences between tendons and ligaments through DTI metrics at 11. 7
T field strength. The current work also found the most feasible range
of b-values of 300-600 s/mm2 which will be best suited for these
tissue types at the given magnetic field strength of 11.7T and get
more reliable DTI measurements.
DTI metrics can provide insight into 3D tissue integrity and
…
*Advisors/Committee Members: Magin, Richard L. (advisor), Wang, Vincent M. (committee member), Stebbins, Glenn T. (committee member), Royston, Thomas J. (committee member), Akpa, Belinda S. (committee member), Zelazny, Anthony M. (committee member).*

Subjects/Keywords: Diffusion Tensor Imaging; Tendon; Ligament; Magnetic Resonance Imaging; ultra-high field; Fractional Anisotropy; Mean Diffusivity; Tractography; b-value optimization

…Specific Aim 3: *Optimization* aim
To determine sensitivity of *b*-*value* on diffusion tensor metrics… …generated using
DTIstudio for two semitendinosus tendons for a *b*-*value* of 200. The fiber tracts… …are
shortened and less dense at this *b*-*value* indicating limited sensitivity of low *b*-*value*… …using
DTIstudio for two semitendinosus tendons for a *b*-*value* of 500. The fiber tracts are long… …and denser at this *b*-*value*…

Record Details Similar Records

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^{th} Edition):

Gupta, A. (2012). Ultra-High Field MR Diffusion Tensor Imaging Characterization of Rabbit Tendons and Ligaments. (Thesis). University of Illinois – Chicago. Retrieved from http://hdl.handle.net/10027/9137

Note: this citation may be lacking information needed for this citation format:

Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^{th} Edition):

Gupta, Aman. “Ultra-High Field MR Diffusion Tensor Imaging Characterization of Rabbit Tendons and Ligaments.” 2012. Thesis, University of Illinois – Chicago. Accessed October 24, 2020. http://hdl.handle.net/10027/9137.

Note: this citation may be lacking information needed for this citation format:

Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^{th} Edition):

Gupta, Aman. “Ultra-High Field MR Diffusion Tensor Imaging Characterization of Rabbit Tendons and Ligaments.” 2012. Web. 24 Oct 2020.

Vancouver:

Gupta A. Ultra-High Field MR Diffusion Tensor Imaging Characterization of Rabbit Tendons and Ligaments. [Internet] [Thesis]. University of Illinois – Chicago; 2012. [cited 2020 Oct 24]. Available from: http://hdl.handle.net/10027/9137.

Note: this citation may be lacking information needed for this citation format:

Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gupta A. Ultra-High Field MR Diffusion Tensor Imaging Characterization of Rabbit Tendons and Ligaments. [Thesis]. University of Illinois – Chicago; 2012. Available from: http://hdl.handle.net/10027/9137

Not specified: Masters Thesis or Doctoral Dissertation