scholarly journals Preliminary Investigation of Static and Dynamic Properties of SLM Lattice Structures for Robotic Applications

2018 ◽  
pp. 260-267 ◽  
Author(s):  
M. Sortino ◽  
G. Totis ◽  
F. Scalzo ◽  
E. Vaglio
Keyword(s):  
Dynamic Properties ◽  
Preliminary Investigation ◽  
Lattice Structures ◽  
Robotic Applications

scholarly journals Basic research of the consideration of additive manufactured lattice structures under thermoand fluid dynamic loads

2019 ◽  
Vol 299 ◽  
pp. 01009
Author(s):  
Karim Abbas ◽  
Laura Thurn ◽  
Julia Kessler ◽  
Fabian Eichler
Keyword(s):  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Basic Research ◽  
Periodic Lattice ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Lightweight Structures

This scientific research deals with lattice structures manufactured with laser powder bed fusion. Laser powder bed fusion is part of additive manufacturing. The so called layered construction is an increasingly used innovative manufacturing process that can be used to realize new design possibilities. Lightweight structures or bionic structures play a key role here. The focus of this work is on periodic lattice structures. In addition to saving resources and reducing the weight of components, lattice structures have particularly pronounced mechanical properties. However, little is known about their thermo- and fluid-dynamic properties. This work describes the first influencing factors of lattice structures ina thermo- and fluid-dynamic context using a case study. The aim of this paper is to evaluate important design and simulation criteria of lattice structures. Different lattice structures are considered, whose strut geometry is varied. The case study is carried out using a heat exchanger. While classical heat exchangers have lamellar structures, the substitution of these by lattice structures is evaluated. Thiswork represents a first consideration of the most important parameters and gives an overview of the most important core points.

Dynamic Continuum Models of Large Platelike Lattice Structures

1991 ◽  
Author(s):  
Usik Lee
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Continuum Models ◽  
Periodic Lattice ◽  
Lattice Structures ◽  
Straightforward Method ◽  
Energy Equivalence ◽  
Mass Matrices ◽  
Equivalent Continuum ◽  
The Continuum

Abstract A rational and straightforward method is introduced for developing continuum models of large platelike periodic lattice structures based on energy equivalence. The procedure for developing continuum plate models involves the use of existing well-defined finite element matrices for the easy calculation of strain and kinetic energies of a repeating cell, from which the reduced stiffness and mass matrices are obtained in terms of continuum degrees-of-freedom defined in this paper. The equivalent continuum plate properties are obtained from the direct comparison of the reduced matrices for continuum plate with those for lattice plate. Free vibration analyses for the continuum and lattice plates are conducted to evaluate the continuum method proposed in this paper. Numerical results show that the present continuum method gives very reliable structural and dynamic properties compared to other well-recognized methods.

Surface ultrastructure of danazol treated rat endometrium: A SEM study

1983 ◽  
Vol 41 ◽  
pp. 556-557
Author(s):  
R.P. Apkarian ◽  
J.S. Sanfilippo
Keyword(s):  
Cross Sections ◽  
Reproductive Tract ◽  
Preliminary Investigation ◽  
Breast Disease ◽  
Distal Segment ◽  
Uterine Horn ◽  
Female Reproductive Tract ◽  
Ultrastructural Changes ◽  
Cycle Phase ◽  
Sprague Dawley

The synthetic androgen danazol, is an isoxazol derivative of ethisterone. It is utilized in the treatment of endometriosis, fibrocystic breast disease, and has a potential use as a contraceptive. A study was designed to evaluate the ultrastructural changes associated with danazol therapy in a rat model. The preliminary investigation of the distal segment of the rat uterine horn was undertaken as part of a larger study intended to elucidate the effects of danazol on the female reproductive tract.Cross-sections (2-3 mm in length) of the distal segment of the uterine horn from sixteen Sprague-Dawley rats were prepared for SEM. Ten rats in estrus served as controls and six danazol treated rats were noted to have alterations of the estrus cycle i.e. a lag in cycle phase or noncycling patterns. Specimens were fixed in 3% glutaraldehyde in 0.05M phosphate buffer containing CaCl2 at pH 7.0-7.4 and chilled to 4°C. After a brief wash in distilled water, specimens were passed through a graded series of ethanol, critical point dryed in CO2 from absolute ethanol, and coated with 6nm Au. Observations were made with an IS1-40 SEM operated at 15kV.

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

1988 ◽  
Vol 46 ◽  
pp. 204-205
Author(s):  
Kazumichi Ogura ◽  
Michael M. Kersker
Keyword(s):  
High Resolution ◽  
Layer Structure ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Beam Current ◽  
Lattice Structures ◽  
Super Lattice ◽  
Different Types ◽  
Backscattered Electron ◽  
Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

A Comparison of the Ultrastructural Morphology of Hepatic Necrosis in BDF1 Mice

1981 ◽  
Vol 39 ◽  
pp. 586-587
Author(s):  
Becky Jackson
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Preliminary Investigation ◽  
Hepatic Necrosis ◽  
Hepatic Tissue ◽  
Pronounced Increase ◽  
Glycogen Store ◽  
Ultrastructural Morphology ◽  
Mitochondrial Integrity ◽  
Glycogen Stores

Preliminary investigation has indicated similarity in hepatic ultrastructural morphology in nutritional deprivation, and cyanide induced hepatic necrosis. Analysis of hepatic tissue has indicated disruption of intracellular membranes, specifically, reduction in rough endoplasmic reticulum (RER) mitochondrial integrity, and glycogen stores. An increase in smooth endoplasmic reticulum (SER) portion was observed.To further investigate the apparent equivalence of necrotic morphology, ultrastructura1ly, BDF1 mice were subjected to senescence, nutritional deprevation, potassium cyanide (KCN) induced toxemia, and acetaminophen induced toxemia. Controls were utilized to ellucidate non-necrotic hepatocellular normals. U1trastructura1 investigation of controls (Fig. 1) shows densely granular RER, abundant glycogen stores, and morphologically normal mitochondria. Subjects with acetaminophen induced necrosis exhibit reduced normal RER with increased levels of dialated, vesicular RER in apparent conversion to SER (Fig. 2), loss of mitochondrial integrity, and glycogen store reduction. Senescent subjects exhibit a pronounced increase in SER and loss of glycogen store. (Fig. 3). Investigation of the senescent SER at high magnification (Fig. 5) indicates that the SER is arising from degranulating and vesiculating RER.

Ultrastructural Effects of Acute Kepone Treatment in Rats

1976 ◽  
Vol 34 ◽  
pp. 286-287
Author(s):  
Richard L. Klein ◽  
Åsa K. Thureson-Klein ◽  
Harihara M. Mehendale
Keyword(s):  
Neurological Disorders ◽  
Corn Oil ◽  
Preliminary Investigation ◽  
Reproductive Capacity ◽  
Ultrastructural Changes ◽  
Lipid Deposition ◽  
Severe Toxicity ◽  
Sprague Dawley ◽  
Ether Anesthesia ◽  
Sprague Dawley Rats

KeponeR (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one) is an insecticide effective against ants and roaches. It can cause severe toxicity in fishes, birds, rodents and man. Prominent effects include hepatic lipid deposition and hypertrophy, impairment of reproductive capacity and neurological disorders. Mitochondrial oligomycin-sensitive Mg2+-ATPase is also inhibited. The present study is a preliminary investigation of tissue ultrastructural changes accompanying physiological signs of acute toxicity, which after two days treatment include: pronounced hypersensitivity and tremor, various degrees of anorexia and adipsia, and decreased weight gain.Three different series of adult male Sprague-Dawley rats (Charles River or CD-I) were treated by intubation with Kepone in corn oil at a dose of 50 mg per kg for 3 successive days or at 200 ppm in food for 8 days. After ether anesthesia, rats were immediately perfused via a cannula in the left ventricle with 4% p-formaldehyde and 0.5% glutaraldehyde in Millonig's phosphate buffer at pH 7.2 for 20-30 min at 22°C.

The distribution of antigen on the surface of RBL-2H3 rat basophilic leukemia cells observed by back-scattered electron imaging

1986 ◽  
Vol 44 ◽  
pp. 274-275
Author(s):  
R.F. Stump ◽  
J.R. Pfeiffer ◽  
JC. Seagrave ◽  
D. Huskisson ◽  
J.M. Oliver
Keyword(s):  
Cell Surface ◽  
Dynamic Properties ◽  
Leukemia Cells ◽  
Antigen Binding ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Rat Basophilic Leukemia Cells ◽  
Electron Imaging ◽  
Basophilic Leukemia

In RBL-2H3 rat basophilic leukemia cells, antigen binding to cell surface IgE-receptor complexes stimulates the release of inflammatory mediators and initiates a series of membrane and cytoskeletal events including a transformation of the cell surface from a microvillous to a lamellar topography. It is likely that dynamic properties of the IgE receptor contribute to the activation of these responses. Fewtrell and Metzger have established that limited crosslinking of IgE-receptor complexes is essential to trigger secretion. In addition, Baird and colleagues have reported that antigen binding causes a rapid immobilization of IgE-receptor complexes, and we have demonstrated an apparent increase with time in the affinity of IgE-receptor complexes for antigen.

Lattice imaging of precipitates in Al-Zn-Mg alloy

1986 ◽  
Vol 44 ◽  
pp. 412-413
Author(s):  
C. K. Wu
Keyword(s):  
Grain Boundaries ◽  
Homogeneous Nucleation ◽  
Alloy System ◽  
Mg Alloy ◽  
List Type ◽  
Lattice Structures ◽  
Type Number ◽  
Orientation Relationships ◽  
Lattice Imaging ◽  
The Matrix

The precipitation phenomenon in Al-Zn-Mg alloy is quite interesting and complicated and can be described in the following categories:(i) heterogeneous nucleation at grain boundaries;(ii) precipitate-free-zones (PFZ) adjacent to the grain boundaries;(iii) homogeneous nucleation of snherical G.P. zones, n' and n phases inside the grains. The spherical G.P. zones are coherent with the matrix, whereas the n' and n phases are incoherent. It is noticed that n' and n phases exhibit plate-like morpholoay with several orientation relationship with the matrix. The high resolution lattice imaging techninue of TEM is then applied to study precipitates in this alloy system. It reveals the characteristics of lattice structures of each phase and the orientation relationships with the matrix.

Nucleosome dynamics

2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  
Keyword(s):  
High Resolution ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Dynamic Properties ◽  
Structure And Dynamics ◽  
Nucleosome Dynamics ◽  
Sharp Focus ◽  
Recent Advances ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.

Sign in / Sign up

Export Citation Format

Share Document