A Graph-Theory-Based Method for Topological and Dimensional Representation of Planar Mechanisms as a Computational Tool for Engineering Design

1987 ◽

Vol 109 (3) ◽

pp. 322-328 ◽

Cited By ~ 1

Author(s):

D. G. Olson ◽

A. G. Erdman ◽

D. R. Riley

Keyword(s):

Graph Theory ◽

Directed Graph ◽

Dimensional Synthesis ◽

Planar Mechanisms

This paper presents an overview of a component-based approach for the dimensional synthesis of planar mechanisms. The components on which the approach is based are called triads, dyads, and free vectors, and can be synthesized for up to five precision positions. A straight-forward method for formulating dimensional synthesis procedures for arbitrarily complex planar mechanisms is developed, and demonstrated by an example using inspection. The method utilizes the concept of the directed graph, which is an enhancement of the usual graph theory representation of mechanisms. Because the method is based on graph theory, it is believed that it could be easily automated.

Download Full-text

Frameworks for Organizing Design Performance Metrics

Volume 1A: 34th Computers and Information in Engineering Conference ◽

10.1115/detc2014-35135 ◽

2014 ◽

Author(s):

Briana Lucero ◽

Peter Ngo ◽

Julie Linsey ◽

Cameron J. Turner

Keyword(s):

Engineering Design ◽

Performance Metrics ◽

Critical Role ◽

Computational Tool ◽

Bond Graphs ◽

Computational Tools ◽

Design For X ◽

Technical Performance ◽

Design By Analogy

Computational tools for aiding design-by-analogy have so far focused on function- and keyword-based retrieval of analogues. Given the critical role of performance and benchmarking in design, there is a need for performance metrics-driven analogy retrieval that is currently unmet. Towards meeting this need, a study has been done to investigate and propose frameworks for organizing the myriad technical performance metrics in engineering design, such as measures of efficiency. Such organizational frameworks are needed for the implementation of a computational tool which can retrieve relevant analogies using performance metrics. The study, which takes a deductive approach, defines a hierarchical taxonomy of performance metrics akin to the functional basis vocabulary of function and flow terms. Its derivation follows from bond graphs, control theory, and Design for X guidelines.

Download Full-text

A First Class of Computational Tools for Preliminary Engineering Design

14th Design Automation Conference ◽

10.1115/detc1988-0060 ◽

1988 ◽

Author(s):

K. L. Wood ◽

E. K. Antonsson

Keyword(s):

Fuzzy Sets ◽

Engineering Design ◽

Preliminary Design ◽

Functional Requirement ◽

Computational Tool ◽

Computational Tools ◽

Input Parameters ◽

Implementation Scheme ◽

Design Calculations ◽

Fuzzy Parameters

Abstract Preliminary engineering design intrinsically consists of imprecise descriptions of the input parameters. We present new conceptual and algorithmic procedures for dealing with such imprecise descriptions. Specifically, a two-part method is outlined for performing design calculations on these “fuzzy” parameters, as well as determining a measure for the parameters’ coupling. By interpreting the input set of variables for preliminary design in terms of fuzzy sets, we demonstrate how the engineer may associate his subjective meaning with the input parameters and the output functional requirement, leading to the foundation of our approach. An example of the method highlights the primary issues and the implementation scheme as a computational tool.

Download Full-text

Reconstruction of Objects from their Projections Using Orthogonal Functions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071788 ◽

1973 ◽

Vol 31 ◽

pp. 268-269

Author(s):

Elrnar Zeitler

Keyword(s):

Unit Area ◽

Three Dimensional ◽

One Dimension ◽

Spatial Density ◽

Dimensional Representation ◽

Orthogonal Functions ◽

Object A ◽

Plane Normal ◽

Dimensional Object ◽

Spatial Density Distribution

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projectionWhere the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.

Download Full-text

Revealing gross three-dimensional structure in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127712 ◽

1987 ◽

Vol 45 ◽

pp. 656-657

Author(s):

Sterling P. Newberry

Keyword(s):

Freeze Drying ◽

Three Dimensional ◽

Dimensional Structure ◽

Small Object ◽

Final Solution ◽

Dimensional Representation ◽

X Ray ◽

Three Dimensional Representation ◽

Freeze Dried ◽

Critical Point Drying

The beautiful three dimensional representation of small object surfaces by the SEM leads one to search for ways to open up the sample and look inside. Could this be the answer to a better microscopy for gross biological 3-D structure? We know from X-Ray microscope images that Freeze Drying and Critical Point Drying give promise of adequately preserving gross structure. Can we slice such preparations open for SEM inspection? In general these preparations crush more readily than they slice. Russell and Dagihlian got around the problem by “deembedding” a section before imaging. This some what defeats the advantages of direct dry preparation, thus we are reluctant to accept it as the final solution to our problem. Alternatively, consider fig 1 wherein a freeze dried onion root has a window cut in its surface by a micromanipulator during observation in the SEM.

Download Full-text

Resolution and measurement in the scanning electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127256 ◽

1987 ◽

Vol 45 ◽

pp. 534-537 ◽

Cited By ~ 2

Author(s):

Michael T. Postek

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Engineering Design ◽

Resolving Power ◽

Practical Applications ◽

Instrument Resolution ◽

Accurate Definition ◽

Definition Of ◽

Scanning Electron ◽

Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

Download Full-text