Development of a Model for the Number of Bends During Stirrup Making Process

2020 ◽  
pp. 69-78
Author(s):  
S. N. Waghmare ◽  
Sagar D. Shelare ◽  
C. K. Tembhurkar ◽  
S. B. Jawalekar
Keyword(s):  
Number Of Bends

scholarly journals Vertebrobasilar Artery Geometry and Bisilar Artery Plaques: A High-Resolution Magnetic Resonance Imaging Stydy

2020 ◽  
Author(s):  
Jinmei Zheng ◽  
Bin Sun ◽  
Ruolan Lin ◽  
Yongqi Teng ◽  
Xihai Zhao ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Large Diameter ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Logistic Regression Models ◽  
Vertebrobasilar Artery ◽  
Number Of Bends ◽  
The Relationship

Abstract Background Atherosclerotic plaques are often present in regions with complicated flow patterns. Vascular morphology plays a role in hemodynamics. In this study, we investigate the relationship between the geometry of the vertebrobasilar artery system and the basilar artery (BA) plaque prevalence.Methods We enrolled 290 patients with posterior circulation ischemic stroke. We distinguished four configurations of the vertebrobasilar artery: Walking, Tuning Fork, Lambda, and No Confluence. The diameter of the vertebral artery (VA) and the number of bends in the intracranial VA segment was assessed using three-dimensional time-of-flight magnetic resonance angiography. We differentiated between multi-bending (≥ 3 bends) and oligo-bending (< 3 bends) VAs. High-resolution magnetic resonance imaging was used to evaluate BA plaques. Logistic regression models examined the relationship between the geometry type and BA plaque prevalence.Results After adjusting for sex, age, body mass index ≥ 28, hypertension, and diabetes mellitus, the Walking, Lambda, and No Confluence geometries were associated with the presence of BA plaque. Patients with multi-bending VAs in both the Walking (71.43%, P = 0.003) and Lambda group (40.43%, P = 0.018) had more plaques compared to patients with oligo-bending VAs in these groups. In the Lambda group, the diameter difference between the VAs was larger in patients with BA plaques than that in patients without BA plaques (1.4 mm vs. 0.9 mm, P < 0.001).Conclusions The Walking, Lambda, and No Confluence geometry, ≥ 3 bends in the VAs, and a large diameter difference between the VAs were associated with the presence of BA plaque.

scholarly journals On edge-intersection graphs of k-bend paths in grids

2010 ◽  
Vol Vol. 12 no. 1 ◽  
Author(s):  
Therese Biedl ◽  
Michal Stern
Keyword(s):  
Conflict Resolution ◽  
Planar Graph ◽  
Bipartite Graph ◽  
Outerplanar Graph ◽  
Line Graphs ◽  
Intersection Graphs ◽  
Grid Networks ◽  
Graph Classes ◽  
International Audience ◽  
Number Of Bends

International audience Edge-intersection graphs of paths in grids are graphs that can be represented such that vertices are paths in a grid and edges between vertices of the graph exist whenever two grid paths share a grid edge. This type of graphs is motivated by applications in conflict resolution of paths in grid networks. In this paper, we continue the study of edge-intersection graphs of paths in a grid, which was initiated by Golumbic, Lipshteyn and Stern. We show that for any k, if the number of bends in each path is restricted to be at most k, then not all graphs can be represented. Then we study some graph classes that can be represented with k-bend paths, for small k. We show that every planar graph has a representation with 5-bend paths, every outerplanar graph has a representation with 3-bend paths, and every planar bipartite graph has a representation with 2-bend paths. We also study line graphs, graphs of bounded pathwidth, and graphs with -regular edge orientations.

scholarly journals Design of Novel Catheter Insertion Device

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Erik K. Bassett ◽  
Alexander Slocum
Keyword(s):  
Angular Displacement ◽  
Compressive Force ◽  
Design Tool ◽  
Catheter Insertion ◽  
Target Space ◽  
Radial Clearance ◽  
Oil Drilling ◽  
Insertion Device ◽  
Adjacent Structures ◽  
Number Of Bends

Poor positioning of needles and catheters may result in repeated attempts at correct placement, injury to adjacent structures or infusions into inappropriate spaces. Existing catheter insertion methods do not uniformly provide feedback of the tip location, nor prevent the needle from going beyond the target space. The purpose of this research was to develop a design tool to be used to create a new catheter insertion device. This device would advance a needle in firm tissue but automatically release it upon entrance into the desired space. The system studied consisted of a flexible filament (OD ∼0.9mm) in compression passing through a tube (ID 1.22mm) with both straight and curved sections. A mathematical model based on oil drilling methods was developed to predict the compressive force dissipated in the filament for any given tube geometry. A correction factor on one of the two terms in the model was necessary to achieve best results, but proved to be accurate for all 100+ tests completed. With it, this model accounted for the following parameters: Angular displacement of tube bends, radial clearance, coefficient of friction, lengths, tube and filament radii, number of bends, moment of inertia, and modulus of elasticity. Implementation of this model should allow for a more safe and effective catheter insertion device.

HVAC CAD Layout Tools: A Case Study of University/Industry Collaboration

1996 ◽  
Author(s):  
Jonathan Cagan ◽  
Richard Clark ◽  
Pratip Dastidar ◽  
Simon Szykman ◽  
Paul Weisser
Keyword(s):  
Collaborative Research ◽  
Hvac Systems ◽  
Design Tools ◽  
Industry Collaboration ◽  
Effective Partnership ◽  
Number Of Bends ◽  
The University ◽  
University Industry ◽  
Traditional Manner

Abstract An effective partnership between industry and the university resulted in the system of design tools for the layout of HVAC systems presented in this paper and illustrated with the design of a heat pump. The system provides tools to assist in the placement of components and routing of tubes between the components. Traditional tubes, tubes that have minimized length and number of bends, and those that are impossible to route in the traditional manner, are generated. The paper provides insight on both the collaborative research interaction and the resulting set of tools.

Residual Stresses in CANDU Feeder Bends: Effect of Bend Radius

2006 ◽  
Author(s):  
M. Yetisir ◽  
R. Donaberger ◽  
R. Rogge
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Cold Work ◽  
Symmetry Plane ◽  
Large Radius ◽  
Bend Radius ◽  
Root Cause ◽  
Number Of Bends ◽  
Crack Susceptibility ◽  
Calculated Level

Since 1997, sections of nine feeder pipes have been removed at the Point Lepreau Generating Station (PLGS) because of cracking. All PLGS feeder cracks are axial in orientation and are located in the feeder bends. In all cases, cracks were either at the inside surface of the bend flanks (approximately 60° from the intrados symmetry plane) or at the outside surface of the bend extrados. Root cause analyses indicated that the residual stress has a significant role in these failures. In a typical feeder, there are a number of bends and welds, which are potential locations of high residual stresses. To reduce inspection scope, or to identify the highest risk components, a relative ranking of crack susceptibility is needed. This can be achieved using the residual stress data of these components. This paper compares the measured residual stress data in tight-radius and large-radius CANDU feeder bends. It was found that residual stresses are significantly higher for the bends with small bend radius (r) over diameter (D) ratios (for example, r/D = 1.5) as compared to those bends with large r/D ratios (r/D &gt; 4). The differences in the magnitude of residual stress are consistent with the measured and calculated level of cold work in the two types of bends. It was concluded that the likelihood of cracking in large-radius bends is significantly smaller than that in tight-radius bends.

scholarly journals FPT-ALGORITHMS FOR MINIMUM-BENDS TOURS

2011 ◽  
Vol 21 (02) ◽  
pp. 189-213 ◽  
Author(s):  
VLADIMIR ESTIVILL-CASTRO ◽  
APICHAT HEEDNACRAM ◽  
FRANCIS SURAWEERA
Keyword(s):  
Traveling Salesman Problem ◽  
Traveling Salesman ◽  
Fixed Parameter Tractable ◽  
Line Segments ◽  
Fpt Algorithms ◽  
Fixed Parameter ◽  
Axis Parallel ◽  
Np Complete ◽  
Number Of Bends ◽  
Straight Lines

This paper discusses the κ-BENDS TRAVELING SALESMAN PROBLEM. In this NP-complete problem, the inputs are n points in the plane and a positive integer κ, and we are asked whether we can travel in straight lines through these n points with at most κ bends. There are a number of applications where minimizing the number of bends in the tour is desirable because bends are considered very costly. We prove that this problem is fixed-parameter tractable (FPT). The proof is based on the kernelization approach. We also consider the RECTILINEAR κ-BENDS TRAVELING SALESMAN PROBLEM, which requires that the line-segments be axis-parallel. 1 Note that a rectilinear tour with κ bends is a cover with κ-line segments, and therefore a cover by lines. We introduce two types of constraints derived from the distinction between line-segments and lines. We derive FPT-algorithms with different techniques and improved time complexity for these cases.

A New Pipe Routing Approach for Aero-Engines by Octree Modeling and Modified Max-Min Ant System Optimization Algorithm

2016 ◽  
Vol 34 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Y.-F. Qu ◽  
D. Jiang ◽  
X.-L. Zhang
Keyword(s):  
Optimization Algorithm ◽  
System Optimization ◽  
Ant System ◽  
Solution Quality ◽  
Dynamic Update ◽  
Pipe Routing ◽  
Efficiency And Effectiveness ◽  
Speed Up ◽  
Aero Engines ◽  
Number Of Bends

AbstractAero-engines usually contain a lot of pipes and cables which have an important influence on product performance and reliability. In this paper, a new pipe routing approach for aero-engines is proposed. First, an adaptive octree modeling method is presented according to the characteristics of the layout space. After considering three types of engineering constraints, the total length of pipelines, the total number of bends and the natural frequency of pipelines are modeled as the optimal objective. Then, a Modified Max-Min Ant System optimization algorithm (MMMAS), which uses layered node selection and dynamic update mechanism, is proposed for pipe routing. For branch pipelines, ant colony searches in groups and parallel to improve the solution quality and speed up the convergence greatly. Finally, numerical comparisons with other current approaches in literatures demonstrate the efficiency and effectiveness of the proposed approach. And a case study of pipe routing for aero-engines is conducted to validate this approach.

Sign in / Sign up

Export Citation Format

Share Document