Designing Developable Mechanisms From Flat Patterns

Volume 10: 44th Mechanisms and Robotics Conference (MR) ◽

10.1115/detc2020-22445 ◽

2020 ◽

Author(s):

Lance P. Hyatt ◽

Amanda Lytle ◽

Spencer P. Magleby ◽

Larry L. Howell

Keyword(s):

Spherical Mechanisms ◽

Tools And Methods ◽

Flat Pattern

Abstract This paper presents tools and methods to design cylindrical and conical developable mechanisms from flat, planar patterns. Equations are presented that relate the link lengths and link angles of planar and spherical mechanisms to the dimensions in a flat configuration. These flat patterns can then be formed into curved, developable mechanisms. Guidelines are established to determine if a mechanism described by a flat pattern can exhibit intramobile or extramobile behavior. A developable mechanism can only potentially exhibit intramobile or extramobile behavior if none of the links extend beyond half of the flat pattern. The behavior of a mechanism can change depending on the location of the cut of the flat pattern. Different joint designs are discussed including lamina emergent torsional (LET) joints. Physical examples are presented.

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A procedure for cross-sectioning materials for TEM analysis without ion milling

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176848 ◽

1990 ◽

Vol 48 (4) ◽

pp. 742-743

Author(s):

J.P. Benedict ◽

Ron Anderson ◽

S. J. Klepeis

Keyword(s):

Surface Topography ◽

Milling Time ◽

Specimen Preparation ◽

Ion Milling ◽

Cleaning Operation ◽

Tem Analysis ◽

Platinum Silicide ◽

Surface Alteration ◽

Polishing Damage ◽

Tools And Methods

Traditional specimen preparation procedures for non-biological samples, especially cross section preparation procedures, involves subjecting the specimen to ion milling for times ranging from minutes to tens of hours. Long ion milling time produces surface alteration, atomic number and rough-surface topography artifacts, and high temperatures. The introduction of new tools and methods in this laboratory improved our ability to mechanically thin specimens to a point where ion milling time was reduced to one to ten minutes. Very short ion milling times meant that ion milling was more of a cleaning operation than a thinning operation. The preferential thinning and the surface topography that still existed in briefly ion milled samples made the study of interfaces between materials such as platinum silicide and silicon difficult. These two problems can be eliminated by completely eliminating the ion milling step and mechanically polishing the sample to TEM transparency with the procedure outlined in this communication. Previous successful efforts leading to mechanically thinned specimens have shown that problems center on tool tilt control, removal of polishing damage, and specimen cleanliness.

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Assessing Language and Literacy Skills of School-Aged Children

Perspectives on School-Based Issues ◽

10.1044/sbi9.2.66 ◽

2008 ◽

Vol 9 (2) ◽

pp. 66-70

Author(s):

Jennifer Walz Garrett

Keyword(s):

Literacy Skills ◽

Assessment Tools ◽

Treatment Goals ◽

Miscue Analysis ◽

Language And Literacy ◽

Speech Language Pathologists ◽

School Aged Children ◽

School Based ◽

Assessment Procedures ◽

Tools And Methods

Abstract School-based speech-language pathologists assess students to establish eligibility, collect baselines for treatment goals, determine progress during intervention and verify generalization of skills. Selecting appropriate assessment tools and methods can be challenging due to time constraints, agency regulations, and availability of tests. This article will describe legal considerations, types of assessments, and the factors involved with the selection and use of various assessment procedures and tools. In addition, speech-language pathologists will learn to calculate words correct per minute (WCPM) and perform miscue analysis, which can provide additional language and literacy information about a child's educational needs.

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