Numerical and Experimental Studies of 3-Dimensional Thermoforming Process

2001 ◽  
Vol 20 (14-15) ◽  
pp. 1182-1190 ◽  
Author(s):  
G. J. Nam ◽  
J. W. Lee
Keyword(s):  
Experimental Studies ◽  
3 Dimensional ◽  
Thermoforming Process

scholarly journals Full-Field Viscoelastic Inflation Response of Bovine Cornea

2008 ◽  
Author(s):  
B. L. Boyce ◽  
T. D. Nguyen ◽  
R. E. Jones
Keyword(s):  
Real Time ◽  
Experimental Studies ◽  
Time Dependent ◽  
Full Field ◽  
3 Dimensional ◽  
Displacement Mapping ◽  
Mapping Tool ◽  
Unique Approach ◽  
In Vivo Characterization

Most previous experimental studies and mechanical cornea models have ignored time-dependence of the cornea’s modulus, with only a few notable exceptions [1–3]. The purpose of the present work was to evaluate the time-dependent properties of cornea tissue independent of scleral contributions in a condition that is as physiologically-relevant as possible without resorting to costly and difficult in vivo characterization. A non-contact 3-dimensional displacement mapping tool was employed to image the entire deformation field across the entire cornea in real-time during pressurization. Unlike prior inflation-based studies, the present study’s unique approach permits dynamic real-time full-field mapping of deformation during inflation for the examination of viscoelasticity, isotropy, and homogeneity.

Estimation of Grasp Envelope Using a 3-Dimensional Kinematic Model of the Hand

2007 ◽  
Vol 51 (15) ◽  
pp. 889-893 ◽  
Author(s):  
Jaewon Choi ◽  
D. Christian Grieshaber ◽  
Thomas J. Armstrong
Keyword(s):  
Kinematic Model ◽  
Experimental Studies ◽  
Design Stage ◽  
Contact Algorithm ◽  
3 Dimensional ◽  
Rotation Method ◽  
Simulation Results ◽  
Practical Information ◽  
Object Shapes ◽  
Simple Contact

A 3-dimensional kinematic model of the hand was developed. The model predicts hand posture using a simple contact algorithm, which detects a contact between hand segments and the object. Using the 3-dimensional kinematic model of the hand, we estimated grasp envelopes because the space requirement for a specific task is an important aspect to be considered in the task's design stage. For this purpose, two hose insertion methods – a straight method and a rotation method – were simulated. The simulation results were compared favorably with the experimental studies by the previous researches. The model can be used to estimate grasp envelopes for varying hand sizes, object sizes, object shapes, and grip types. The model gives useful and practical information about the grasp envelope to the engineers who design parts or work space.

Alternative manufacturing process of 3-dimensional interconnect device using thermoforming process

2021 ◽  
Vol 127 ◽  
pp. 114373
Author(s):  
S. Zulfiqar ◽  
A.A. Saad ◽  
M.F.M. Sharif ◽  
Z. Samsudin ◽  
M.Y.T. Ali ◽  
...  
Keyword(s):  
Manufacturing Process ◽  
3 Dimensional ◽  
Thermoforming Process

PEEK Dental Implants: A Review of the Literature

2013 ◽  
Vol 39 (6) ◽  
pp. 743-749 ◽  
Author(s):  
Andreas Schwitalla ◽  
Wolf-Dieter Müller
Keyword(s):  
Stress Distribution ◽  
Dental Implants ◽  
Literature Search ◽  
Experimental Studies ◽  
Review Of The Literature ◽  
Bone Implant ◽  
3 Dimensional ◽  
Alternative Material ◽  
Dimensional Finite Element ◽  
Chemical Modulation

The insertion of dental implants containing titanium can be associated with various complications (eg, hypersensitivity to titanium). The aim of this article is to evaluate whether there are existing studies reporting on PEEK (polyetheretherketone) as an alternative material for dental implants. A systematic literature search of PubMed until December 2010 yielded 3 articles reporting on dental implants made from PEEK. One article analyzed stress distribution in carbon fiber-reinforced PEEK (CFR-PEEK) dental implants by the 3-dimensional finite element method, demonstrating higher stress peaks due to a reduced stiffness compared to titanium. Two articles reported on investigations in mongrel dogs. The first article compared CFR-PEEK to titanium-coated CFR-PEEK implants, which were inserted into the femurs and evaluated after 4 and 8 weeks. The titanium-coated implants showed significantly higher bone-implant contact (BIC) rates. In a second study, implants of pure PEEK were inserted into the mandibles beside implants made from titanium and zirconia and evaluated after 4 months, where PEEK presented the lowest BIC. The existing articles reporting on PEEK dental implants indicate that PEEK could represent a viable alternative material for dental implants. However, further experimental studies on the chemical modulation of PEEK seem to be necessary, mainly to increase the BIC ratio and to minimize the stress distribution to the peri-implant bone.

Longitudinal Dynamics of 3-Dimensional Components of Selfhood After Severe Traumatic Brain Injury: A qEEG Case Study

2017 ◽  
Vol 48 (5) ◽  
pp. 327-337 ◽  
Author(s):  
Andrew A. Fingelkurts ◽  
Alexander A. Fingelkurts
Keyword(s):  
Brain Injury ◽  
Experimental Studies ◽  
Diffuse Axonal Injury ◽  
Brain Network ◽  
The Self ◽  
Functional Network ◽  
3 Dimensional ◽  
Brain Functional Network ◽  
Rehabilitation Programs ◽  
Clinically Significant

In this report, we describe the case of a patient who sustained extremely severe traumatic brain damage with diffuse axonal injury in a traffic accident and whose recovery was monitored during 6 years. Specifically, we were interested in the recovery dynamics of 3-dimensional components of selfhood (a 3-dimensional construct model for the complex experiential selfhood has been recently proposed based on the empirical findings on the functional-topographical specialization of 3 operational modules of brain functional network responsible for the self-consciousness processing) derived from the electroencephalographic (EEG) signal. The analysis revealed progressive (though not monotonous) restoration of EEG functional connectivity of 3 modules of brain functional network responsible for the self-consciousness processing, which was also paralleled by the clinically significant functional recovery. We propose that restoration of normal integrity of the operational modules of the self-referential brain network may underlie the positive dynamics of 3 aspects of selfhood and provide a neurobiological mechanism for their recovery. The results are discussed in the context of recent experimental studies that support this inference. Studies of ongoing recovery after severe brain injury utilizing knowledge about each separate aspect of complex selfhood will likely help to develop more efficient and targeted rehabilitation programs for patients with brain trauma.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

Structural preservation and absolute contrast of catalase crystal sections prepared with tannic acid

1983 ◽  
Vol 41 ◽  
pp. 448-449
Author(s):  
C.W. Akey ◽  
M. Szalay ◽  
S.J. Edelstein
Keyword(s):  
Tannic Acid ◽  
Beef Heart ◽  
X Rays ◽  
Screw Axis ◽  
General Applicability ◽  
Thin Sections ◽  
Beef Liver ◽  
3 Dimensional ◽  
Dimensional Reconstruction ◽  
Structural Preservation

Three methods of obtaining 20 Å resolution in sectioned protein crystals have recently been described. They include tannic acid fixation, low temperature embedding and grid sectioning. To be useful for 3-dimensional reconstruction thin sections must possess suitable resolution, structural fidelity and a known contrast. Tannic acid fixation appears to satisfy the above criteria based on studies of crystals of Pseudomonas cytochrome oxidase, orthorhombic beef liver catalase and beef heart F1-ATPase. In order to develop methods with general applicability, we have concentrated our efforts on a trigonal modification of catalase which routinely demonstrated a resolution of 40 Å. The catalase system is particularly useful since a comparison with the structure recently solved with x-rays will permit evaluation of the accuracy of 3-D reconstructions of sectioned crystals.Initially, we re-evaluated the packing of trigonal catalase crystals studied by Longley. Images of the (001) plane are of particular interest since they give a projection down the 31-screw axis in space group P3121. Images obtained by the method of Longley or by tannic acid fixation are negatively contrasted since control experiments with orthorhombic catalase plates yield negatively stained specimens with conditions used for the larger trigonal crystals.

Deviations from Ideal Decagonal Symmetry in Electron Diffraction Patterns of the “Decagonal” Phase in the Al-Co-Cu Alloy System

1991 ◽  
Vol 49 ◽  
pp. 914-915
Author(s):  
Atul S. Ramani ◽  
Earle R. Ryba ◽  
Paul R. Howell
Keyword(s):  
Electron Microscope ◽  
Alloy System ◽  
Nominal Composition ◽  
Dimensional Lattice ◽  
3 Dimensional ◽  
Decagonal Phase ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Lattice Periodicity ◽  
Diffraction Patterns

The “decagonal” phase in the Al-Co-Cu system of nominal composition Al65CO15Cu20 first discovered by He et al. is especially suitable as a topic of investigation since it has been claimed that it is thermodynamically stable and is reported to be periodic in the dimension perpendicular to the plane of quasiperiodic 10-fold symmetry. It can thus be expected that it is an important link between fully periodic and fully quasiperiodic phases. In the present paper, we report important findings of our transmission electron microscope (TEM) study that concern deviations from ideal decagonal symmetry of selected area diffraction patterns (SADPs) obtained from several “decagonal” phase crystals and also observation of a lattice of main reflections on the 10-fold and 2-fold SADPs that implies complete 3-dimensional lattice periodicity and the fundamentally incommensurate nature of the “decagonal” phase. We also present diffraction evidence for a new transition phase that can be classified as being one-dimensionally quasiperiodic if the lattice of main reflections is ignored.

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