Computation of Natural Frequencies of Planar Lattice Structure.

1987 ◽  
Author(s):  
James H. Williams ◽  
Nagem Jr. ◽  
Raymond J.
Keyword(s):  
Natural Frequencies ◽  
Lattice Structure ◽  
Planar Lattice

scholarly journals Vibration Analysis of Fused Deposition Modelling Printed Lattice Structure Bar for Application in Automated Device

2018 ◽  
Vol 7 (3.17) ◽  
pp. 21 ◽  
Author(s):  
M S. Azmi ◽  
R Ismail ◽  
R Hasan ◽  
M R. Alkahari
Keyword(s):  
Fused Deposition Modeling ◽  
Natural Frequencies ◽  
Lattice Structure ◽  
Acrylonitrile Butadiene Styrene ◽  
Force Sensor ◽  
Body Part ◽  
Fused Deposition Modelling ◽  
Vibration Testing ◽  
Fused Deposition ◽  
Vibration Technique

The purpose of this study is to investigate the effect of size of strut radius to the natural frequencies of acrylonitrile-butadiene-styrene (ABS) polymer lattice-structure bar material by using vibration technique. The lattice structured cellular material parts with body-centered-cubic (BCC) topological design are manufactured using fused deposition modeling (FDM) additive manufacturing (AM) technique with aim to reduce the overall weight of automated device. The specimens are tested by using set up consist of fabricated test rig, accelerometer, force sensor, power amplifier, shaker and signal generator/analyzer. The first mode natural frequency obtained from the vibration testing for specimen with 1.0 mm strut radius is 278 Hz while specimen with 1.2 mm strut radius is 441 Hz. The results obtained from vibration testing show that bigger size of strut radius will yield higher natural frequencies and the lattice structure bar is suitable for use as arm body part in automated device. By utilizing FDM AM, industry will be able to benefit in term of saving in fabrication cost as well as energy consumption. 

Natural Frequencies of a Simple 3D Printed Lattice Structure

2021 ◽  
Author(s):  
Katarina Monkova ◽  
Peter Pavol Monka ◽  
Jan Vanca ◽  
Romana Hricova ◽  
Lucia Knapcikova ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Lattice Structure ◽  
3D Printed

Structural analysis of the photosynthetic membrane from Ectothiorhodospira halochloris

1983 ◽  
Vol 41 ◽  
pp. 740-741
Author(s):  
H. Engelhardt ◽  
R. Guckenberger ◽  
W. Baumeister
Keyword(s):  
Lattice Structure ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Rhodopseudomonas Viridis ◽  
Photosynthetic Membranes ◽  
Ectothiorhodospira Halochloris ◽  
Main Components

Bacterial photosynthetic membranes contain, apart from lipids and electron transport components, reaction centre (RC) and light harvesting (LH) polypeptides as the main components. The RC-LH complexes in Rhodopseudomonas viridis membranes are known since quite seme time to form a hexagonal lattice structure in vivo; hence this membrane attracted the particular attention of electron microscopists. Contrary to previous claims in the literature we found, however, that 2-D periodically organized photosynthetic membranes are not a unique feature of Rhodopseudomonas viridis. At least five bacterial species, all bacteriophyll b - containing, possess membranes with the RC-LH complexes regularly arrayed. All these membranes appear to have a similar lattice structure and fine-morphology. The lattice spacings of the Ectothiorhodospira haloohloris, Ectothiorhodospira abdelmalekii and Rhodopseudomonas viridis membranes are close to 13 nm, those of Thiocapsa pfennigii and Rhodopseudomonas sulfoviridis are slightly smaller (∼12.5 nm).

Electron-Channelling Patterns: Principles and Techniques

1976 ◽  
Vol 34 ◽  
pp. 400-401
Author(s):  
David C. Joy
Keyword(s):  
Crystal Structure ◽  
Electron Flux ◽  
Lattice Structure ◽  
Incident Beam ◽  
Bloch Wave ◽  
Crystalline Solid ◽  
Angle Of Incidence ◽  
Electron Channelling ◽  
Regular Arrangement ◽  
Backscattered Signals

In a crystalline solid the regular arrangement of the lattice structure influences the interaction of the incident beam with the specimen, leading to changes in both the transmitted and backscattered signals when the angle of incidence of the beam to the specimen is changed. For the simplest case the electron flux inside the specimen can be visualized as the sum of two, standing wave distributions of electrons (Fig. 1). Bloch wave 1 is concentrated mainly between the atom rows and so only interacts weakly with them. It is therefore transmitted well and backscattered weakly. Bloch wave 2 is concentrated on the line of atom centers and is therefore transmitted poorly and backscattered strongly. The ratio of the excitation of wave 1 to wave 2 varies with the angle between the incident beam and the crystal structure.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

Structure of stacking faults in pyrite using TEM techniques

1992 ◽  
Vol 50 (1) ◽  
pp. 358-359
Author(s):  
Raja Subramanian ◽  
Kenneth S. Vecchio
Keyword(s):  
Lattice Structure ◽  
Stacking Faults ◽  
Covalent Bond ◽  
Group Symmetry ◽  
Iron Pyrite ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Contrast Analysis ◽  
Chlorine Ions

The structure of stacking faults and partial dislocations in iron pyrite (FeS2) have been studied using transmission electron microscopy. Pyrite has the NaCl structure in which the sodium ions are replaced by iron and chlorine ions by covalently-bonded pairs of sulfur ions. These sulfur pairs are oriented along the <111> direction. This covalent bond between sulfur atoms is the strongest bond in pyrite with Pa3 space group symmetry. These sulfur pairs are believed to move as a whole during dislocation glide. The lattice structure across these stacking faults is of interest as the presence of these stacking faults has been preliminarily linked to a higher sulfur reactivity in pyrite. Conventional TEM contrast analysis and high resolution lattice imaging of the faulted area in the TEM specimen has been carried out.

Distortion in lattice-resolution scanned-probe microscope images

1993 ◽  
Vol 51 ◽  
pp. 522-523
Author(s):  
L. Fei
Keyword(s):  
Film Studies ◽  
Lattice Structure ◽  
Substrate Material ◽  
Repulsive Force ◽  
Instrument Calibration ◽  
Microscope Images ◽  
Probe Microscope ◽  
Electron Microscopes ◽  
Diffraction Patterns ◽  
Lattice Resolution

Scanned probe microscopes (SPM) have been widely used for studying the structure of a variety material surfaces and thin films. Interpretation of SPM images, however, remains a debatable subject at best. Unlike electron microscopes (EMs) where diffraction patterns and images regularly provide data on lattice spacings and angles within 1-2% and ∽1° accuracy, our experience indicates that lattice distances and angles in raw SPM images can be off by as much as 10% and ∽6°, respectively. Because SPM images can be affected by processes like the coupling between fast and slow scan direction, hysteresis of piezoelectric scanner, thermal drift, anisotropic tip and sample interaction, etc., the causes for such a large discrepancy maybe complex even though manufacturers suggest that the correction can be done through only instrument calibration.We show here that scanning repulsive force microscope (SFM or AFM) images of freshly cleaved mica, a substrate material used for thin film studies as well as for SFM instrument calibration, are distorted compared with the lattice structure expected for mica.

Compressive properties of the lattice structure with a new process

2020 ◽  
Vol 35 (23-24) ◽  
pp. 3157-3169
Author(s):  
Qingyuan Xu ◽  
Shuguang Li ◽  
Runsheng Hu ◽  
Mengmeng Liu ◽  
Dong Wang ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Compressive Properties ◽  
New Process

Abstract

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