Axial Strain Measurements in Skeletal Muscle at Various Strain Rates

A noncontact optical system using high speed image analysis to measure local tissue deformations and axial strains along skeletal muscle is described. The spatial resolution of the system was 20 pixels/cm and the accuracy was ±0.125mm. In order to minimize the error associated with discrete data used to characterize a continuous strain field, the displacement data were fitted with a third order polynomial and the fitted data differentiated to measure surface strains using a Lagrangian finite strain formulation. The distribution of axial strain along the muscle-tendon unit was nonuniform and rate dependent. Despite a variation in local strain distribution with strain rate, the maximum axial strain, Exx = 0.614 ± 0.045 mm/mm, was rate insensitive and occurred at the failure site for all tests. The frequency response of the video system (1000 Hz) and the measurement of a continuous strain field along the entire length of the structure improve upon previous noncontact optical systems for measurement of surface strains in soft tissues.

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Failure Site Transition During Drop Testing of Printed Wiring Assemblies

Advances in Electronic Packaging, Parts A, B, and C ◽

10.1115/ipack2005-73014 ◽

2005 ◽

Cited By ~ 3

Author(s):

J. Varghese ◽

A. Dasgupta

Keyword(s):

Strain Rate ◽

Strain Energy ◽

High Speed ◽

Local Strain ◽

Surface Mount ◽

Rate Dependent ◽

Bend Tests ◽

Consistency Of The Test ◽

The Impact ◽

Failure Site

This paper is part of an ongoing effort to develop a test methodology to examine the durability of surface mount interconnects under impact loading conditions. Literature indicates that as the drop height is increased, there is a transition in the failure site from the ductile solder to the brittle intermetallic. Not much work has been done to understand this phenomenon. This study considers damage accumulated in the interconnects in terms of the local strain in the printed wiring assembly (PWA), local strain rate and component acceleration. The advantage is that the results are less dependant on structure and loading, because damage is quantified in terms of specimen response rather than the loading. A simple test specimen is fabricated to concentrate the study on interconnect failure mechanisms. An instrumented, repeatable test setup is developed to conduct high speed bend tests and drop tests on the specimen. All tests are replicated twice for proof of consistency of the test data. The paper presents the results of the high speed bend tests. As expected, the durability of the specimen decreases monotonically with PWA strain. On the other hand, the durability first increases and then decreases as the PWA strain rate increases. Failure analysis shows a transition in the failure site from solder to intermetallic. It is hypothesized that for a given package design, the rate dependent material properties determine the partitioning of the strain energy of deformation. Yield stress of the solder and fracture toughness of the intermetallic are identified as the key parameters. More tests are needed to understand this rate dependent strain energy partitioning. The end goal is to develop a consistent, accurate and generic methodology for ranking the impact durability of different surface mount interconnects technologies.

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Strain analysis with nanometer resolution using a conventional transmission electron microsopy technique: electron diffraction contrast imaging revisited

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137215 ◽

1995 ◽

Vol 53 ◽

pp. 168-169

Author(s):

Koenraad G F Janssens ◽

Omer Van der Biest ◽

Jan Vanhellemont ◽

Herman E Maes ◽

Robert Hull

Keyword(s):

Electron Diffraction ◽

Strain Field ◽

Elastic Strain ◽

Strain Analysis ◽

Local Strain ◽

Contrast Imaging ◽

Strain Characterization ◽

Physical Mechanisms ◽

Diffraction Contrast ◽

Transmission Electron

There is a growing need for elastic strain characterization techniques with submicrometer resolution in several engineering technologies. In advanced material science and engineering the quantitative knowledge of elastic strain, e.g. at small particles or fibers in reinforced composite materials, can lead to a better understanding of the underlying physical mechanisms and thus to an optimization of material production processes. In advanced semiconductor processing and technology, the current size of micro-electronic devices requires an increasing effort in the analysis and characterization of localized strain. More than 30 years have passed since electron diffraction contrast imaging (EDCI) was used for the first time to analyse the local strain field in and around small coherent precipitates1. In later stages the same technique was used to identify straight dislocations by simulating the EDCI contrast resulting from the strain field of a dislocation and comparing it with experimental observations. Since then the technique was developed further by a small number of researchers, most of whom programmed their own dedicated algorithms to solve the problem of EDCI image simulation for the particular problem they were studying at the time.

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Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

Tire Science and Technology ◽

10.2346/1.2965832 ◽

2008 ◽

Vol 36 (3) ◽

pp. 211-226 ◽

Cited By ~ 9

Author(s):

F. Liu ◽

M. P. F. Sutcliffe ◽

W. R. Graham

Keyword(s):

High Speed ◽

Slip Rate ◽

Material Model ◽

Contact Forces ◽

Block Modeling ◽

Rate Dependent ◽

Linear Viscoelastic Material ◽

Linear Viscoelastic ◽

The Impact ◽

Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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High speed optical switching gain based EDFA model with 30 Gb/s NRZ modulation code in optical systems

Journal of Optical Communications ◽

10.1515/joc-2020-0223 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Mahmoud M. A. Eid ◽

Ahmed Nabih Zaki Rashed ◽

Keyword(s):

Optical Fiber ◽

High Speed ◽

Optical Switching ◽

Fiber Amplifier ◽

Optical Systems ◽

Power Budget ◽

Erbium Doped Fiber Amplifier ◽

Amplifier Model ◽

Modulation Rate ◽

Modulation Code

AbstractThis study presents high speed optical switching gain based Erbium doped fiber amplifier model. By using the proposed model the optical fiber loss can be minimized. The system is stabilized with the power budget of 25.875 mW a long 75 km as a length of optical fiber in this study can be verified. The modulation rate of 10 Gb/s can be upgrade up to reach 30 Gb/s. The suitable power for the optical transmitter is −2.440 dBm and NRZ modulation code is verified. The receiver sensitivity can be upgraded with the minimum bit error rate and max Q factor are 1.806 e−009 and 5.899.

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Session TU3A: High Speed ICs and Technologies for Optical Systems

2004 IEE Radio Frequency Integrated Circuits (RFIC) Systems Digest of Papers RFIC-04 ◽

10.1109/rfic.2004.1320605 ◽

2004 ◽

Keyword(s):

High Speed ◽

Optical Systems

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A micromirror array with annular partitioning for high-speed random-access axial focusing

Light Science & Applications ◽

10.1038/s41377-020-00420-6 ◽

2020 ◽

Vol 9 (1) ◽

Author(s):

Nathan Tessema Ersumo ◽

Cem Yalcin ◽

Nick Antipa ◽

Nicolas Pégard ◽

Laura Waller ◽

...

Keyword(s):

Adaptive Optics ◽

Visual Information ◽

High Speed ◽

Random Access ◽

General Purpose ◽

Phase Shifting ◽

Optical Systems ◽

Piston Motion ◽

Refresh Rate ◽

Circular Symmetry

Abstract Dynamic axial focusing functionality has recently experienced widespread incorporation in microscopy, augmented/virtual reality (AR/VR), adaptive optics and material processing. However, the limitations of existing varifocal tools continue to beset the performance capabilities and operating overhead of the optical systems that mobilize such functionality. The varifocal tools that are the least burdensome to operate (e.g. liquid crystal, elastomeric or optofluidic lenses) suffer from low (≈100 Hz) refresh rates. Conversely, the fastest devices sacrifice either critical capabilities such as their dwelling capacity (e.g. acoustic gradient lenses or monolithic micromechanical mirrors) or low operating overhead (e.g. deformable mirrors). Here, we present a general-purpose random-access axial focusing device that bridges these previously conflicting features of high speed, dwelling capacity and lightweight drive by employing low-rigidity micromirrors that exploit the robustness of defocusing phase profiles. Geometrically, the device consists of an 8.2 mm diameter array of piston-motion and 48-μm-pitch micromirror pixels that provide 2π phase shifting for wavelengths shorter than 1100 nm with 10–90% settling in 64.8 μs (i.e., 15.44 kHz refresh rate). The pixels are electrically partitioned into 32 rings for a driving scheme that enables phase-wrapped operation with circular symmetry and requires <30 V per channel. Optical experiments demonstrated the array’s wide focusing range with a measured ability to target 29 distinct resolvable depth planes. Overall, the features of the proposed array offer the potential for compact, straightforward methods of tackling bottlenecked applications, including high-throughput single-cell targeting in neurobiology and the delivery of dense 3D visual information in AR/VR.

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A simple hydrodynamic model for the strain field produced in a target by the penetration of a high speed long rod projectile

International Journal of Engineering Science ◽

10.1016/0020-7225(78)90070-8 ◽

1978 ◽

Vol 16 (11) ◽

pp. 845-858 ◽

Cited By ~ 21

Author(s):

A. Tate

Keyword(s):

Hydrodynamic Model ◽

Strain Field ◽

High Speed ◽

Long Rod

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Diamond-Like Carbon Coating—It'S Application for Polymeric Substrates

MRS Proceedings ◽

10.1557/proc-239-647 ◽

1991 ◽

Vol 239 ◽

Author(s):

Fred M. Kimock ◽

Alex J. Hsieh ◽

Peter G. Dehmer ◽

Pearl W. Yip

Keyword(s):

High Speed ◽

Protective Coatings ◽

Ion Beam ◽

Chemical Exposure ◽

Optical Systems ◽

Impact Behavior ◽

Organic Liquids ◽

Diamond Like Carbon ◽

Dlc Coating ◽

The Impact

ABSTRACTWe report on a recently commercialized Diamond-Like Carbon (DLC) coating that has been deposited on polycarbonate at near room temperature, via a unique ion beam system. Aspects of high speed impact behavior, chemical resistance, abrasion resistance, and thermal stability of the coating are examined. Results of scanning electron microscopy studies indicate that adhesion of the DLC coating is very good; no delamination of the coating was found on ballistically tested specimens. The well-bonded DLC coating did not cause the impact performance of polycarbonate to become brittle. Chemical exposure test results show that the DLC coating is capable of protecting polycarbonate from chemical attack by aggressive organic liquids. These ion beam deposited DLC coatings have considerable potential as protective coatings for optical systems.

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Damage Observation and Analysis of a Rock Brazilian Disc Using High-Speed DIC Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.70.87 ◽

2011 ◽

Vol 70 ◽

pp. 87-92 ◽

Cited By ~ 9

Author(s):

Shao Peng Ma ◽

Dong Yan ◽

Xian Wang ◽

Yan Yan Cao

Keyword(s):

Strain Field ◽

Damage Evolution ◽

High Speed ◽

Failure Process ◽

Tensile Load ◽

Brazilian Test ◽

Elastic Model ◽

Strain Fields ◽

Brazilian Disc ◽

Damage And Failure

Observation of damage evolution is of great importance to the understanding of the failure process of rock materials. High-speed DIC system is constructed and used to observe the strain field evolution of the granodiorite disc in Brazilian test. The strain fields at different load levels are analyzed based on the stain abnormality indicator (SAI) which is the ratio of the strain measured in experiment to the strain from theoretical solution in an isotropy and elastic model. SAI could be used to indicate the damage in the specimen. The process of damage and failure of the specimen in Brazilian disc test is quantitatively analyzed and deeply discussed according to the strain fields and the statistics of SAI. Experimental results in this paper show that the failure process of the disc specimen in Brazilian test is not simple crack propagation under tensile load, but a complicated damage evolution procedure.

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