Bubble Wall Rupture Model for Open Cell Structure in Starch/Fiber Heterogeneous Composites

2020 ◽  
Vol 14 (2) ◽  
pp. 169-177
Author(s):  
Chuan-Wei Zhang ◽  
Fang-Yi Li ◽  
Jian-Feng Li ◽  
Hai-Yang Lu ◽  
Geng Wang
Keyword(s):  
Cell Structure ◽  
Local Stress ◽  
Point Of View ◽  
Stress Model ◽  
Bubble Wall ◽  
Open Cell ◽  
Biodegradable Composite ◽  
Cell Structures ◽  
Rupture Model ◽  
Conventional Models

Starch/fiber heterogeneous composites were prepared through thermos-cavity foaming machine. Open cell structures are widely distributed in the heterogeneous composites. Bubble wall rupture is an inevitable stage in the formation of open cells. Different from the conventional models to explain the bubble wall rupture from the energy and the wave point of view, this study suggests the "local thinning ultimate stress" model to reveal the bubble wall rupture from the stress perspective. The local stress of the starch bubble wall is increased with the thinning of the bubble wall. The bubble wall ruptures when local stress exceeds the ultimate surface tension. Starch slurry retraction occurs after bubble wall rupturing. The elastic retraction drives partially open cells to fully open cell morphologies in the starch/fiber heterogeneous composite. The developed mechanism was validated by starch/fiber slurry with different viscosities to design a novel biodegradable composite with fully open cell structures.

scholarly journals Improved Mechanical and Sound Absorption Properties of Open Cell Silicone Rubber Foam with NaCl as the Pore-Forming Agent

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 195
Author(s):  
Longgui Peng ◽  
Lei Lei ◽  
Yongqiang Liu ◽  
Lifei Du
Keyword(s):  
Silicone Rubber ◽  
Sound Absorption ◽  
Cell Structure ◽  
Impedance Matching ◽  
Sound Waves ◽  
Absorption Properties ◽  
Open Cell ◽  
Cell Structures ◽  
The Matrix ◽  
Addition Amount

Porous materials hold great potential in the field of sound absorption, but the most abundantly used materials, such as Polyurethane (PU) foam and polyvinyl chloride (PVC) foam, would inevitably bring environmental harms during fabrication. In this study, the nontoxic addition-molded room temperature vulcanized silicone rubber is chosen as the matrix, and NaCl particles are chosen as the pore forming agent to prepare open cell foams via the dissolve-separating foaming method. The effect of different amounts of NaCl (0–100 phr) on the cell structure, mechanical and sound absorption properties is investigated and analyzed. The results indicate that the cell structure could be tailored via changing the addition amount of NaCl, and open cell silicon rubber foams could be achieved with more than 20 phr NaCl addition. Open cell silicon foams show the most effective sound absorption for sound waves in middle frequency (1000–2000 Hz), which should be attributed to the improved impedance matching caused by the open cell structures. Additionally, the mechanical properties, including hardness, tensile strength and corresponding elastic properties, gradually decay to a steady value with the increasing addition amount of NaCl. Therefore, open cell silicone rubber foams are capable of sound absorption in middle frequency.

scholarly journals Lipidomics study of plasma from patients suggest that ALS and PLS are part of a continuum of motor neuron disorders

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Estela Area-Gomez ◽  
D. Larrea ◽  
T. Yun ◽  
Y. Xu ◽  
J. Hupf ◽  
...  
Keyword(s):  
Motor Neuron ◽  
Motor Neurons ◽  
Cell Structure ◽  
Disease Onset ◽  
Point Of View ◽  
Motor Dysfunction ◽  
Cellular Processes ◽  
Progressive Muscle Weakness ◽  
Human Pathology ◽  
Lateral Sclerosis

AbstractMotor neuron disorders (MND) include a group of pathologies that affect upper and/or lower motor neurons. Among them, amyotrophic lateral sclerosis (ALS) is characterized by progressive muscle weakness, with fatal outcomes only in a few years after diagnosis. On the other hand, primary lateral sclerosis (PLS), a more benign form of MND that only affects upper motor neurons, results in life-long progressive motor dysfunction. Although the outcomes are quite different, ALS and PLS present with similar symptoms at disease onset, to the degree that both disorders could be considered part of a continuum. These similarities and the lack of reliable biomarkers often result in delays in accurate diagnosis and/or treatment. In the nervous system, lipids exert a wide variety of functions, including roles in cell structure, synaptic transmission, and multiple metabolic processes. Thus, the study of the absolute and relative concentrations of a subset of lipids in human pathology can shed light into these cellular processes and unravel alterations in one or more pathways. In here, we report the lipid composition of longitudinal plasma samples from ALS and PLS patients initially, and after 2 years following enrollment in a clinical study. Our analysis revealed common aspects of these pathologies suggesting that, from the lipidomics point of view, PLS and ALS behave as part of a continuum of motor neuron disorders.

Porous Bioceramics (Open Cell Foams) Expanded in Vacuum

2006 ◽  
Vol 309-311 ◽  
pp. 1023-1026
Author(s):  
E.T. Uzumaki ◽  
C.S. Lambert
Keyword(s):  
Zirconium Oxide ◽  
Cell Structure ◽  
The Body ◽  
Carbon Coatings ◽  
Open Cell ◽  
Glass Foam ◽  
Open Cell Foams ◽  
Titanium Foam ◽  
Porous Bioceramics ◽  
Scanning Electron

In this study, porous bioceramics (titanium foam with diamond-like carbon coatings, glass foam and zirconium oxide foam) were produced using expansion in vacuum. The porosity, the pore size and pore morphology can be adjusted in agreement with the application. The different 3D structures were obtained by varying the parameters of the process. The microstructure and morphology of the porous materials were observed by scanning electron microscopy (SEM) and optical microscopy. The foam exhibit an open-cell structure with interconnected macropores, which provide the potential for tissue ingrowths and the transport of the body fluids.

Fuel Cells vs. Competing Technologies

2003 ◽  
Author(s):  
Supramanian Srinivasan ◽  
Lakshmi Krishnan ◽  
Andrew B. Bocarsly ◽  
Kan-Lin Hsueh ◽  
Chiou-Chu Lai ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Direct Methanol Fuel Cells ◽  
Cell Structure ◽  
Proton Exchange ◽  
Point Of View ◽  
Direct Methanol ◽  
Energy Conversion Systems ◽  
Competing Technologies

Investments of over $1 B have been made for Fuel Cell R&D over the past five decades, for space and terrestrial applications; the latter includes military, residential power and heating, transportation and remote and portable power. The types of fuel cells investigated for these applications are PEMFCs (proton exchange membrane fuel cells), AFCs (alkaline fuel cells), DMFCs (direct methanol fuel cells), PAFCs (phosphoric acid fuel cells), MCFCs (molten carbon fuel cells), SOFCs (solid oxide fuel cells). Cell structure, operating principles, and characteristics of each type of fuel cell is briefly compared. The performances of fuel cells vs. competing technologies are analyzed. The key issues are which of these energy conversion systems are technologically advanced and economically favorable and can meet the lifetime, reliability and safety requirements. This paper reviews fuel cells vs. competing technologies in each application category from a scientific and engineering point of view.

Computational and Experimental Studies of Cellular Samples Manufactured Using Additive Methods for Use in Advanced Lightweight Designs of Engine Parts

2020 ◽  
Author(s):  
Liubov Magerramova ◽  
Michael Volkov ◽  
Oleg Volgin ◽  
Pavel Kolos
Keyword(s):  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Cell Structure ◽  
Experimental Studies ◽  
Cellular Structures ◽  
Uniaxial Tensile ◽  
Porous Structures ◽  
Lattice Cell ◽  
Cell Structures ◽  
Homogeneous Materials

Abstract The use of cellular structures is one way to reduce the weight of engine parts. Cellular structures are used to provide rigidity and strength for parts subject to compression, bending, and shock loads. Failure of the individual elements of a lattice/cell structure does not result in the destruction of the entire part; this stands in contrast to the structure of a conventional homogeneous metal object, in which cracks will continue to increase with increasing load, causing the destruction of the entire part. Lattice/cell structures have relatively high characteristics of rigidity and strength, excellent thermal insulation properties, energy absorption characteristics, and high fatigue resistance. The use of this type of structure in engine part construction opens up new opportunities for advanced aviation applications. However, the deformation behavior of porous and metallic structures differs significantly from that of conventional homogeneous materials. Samples with cellular and porous structures are themselves designs. Therefore, procedures for strength testing and interpretation of experimental results for cellular and porous structures differ from those for samples derived from homogeneous materials. The criteria for determining the properties of cellular structures include density, stiffness, ability to accumulate energy, etc. These parameters depend on the configuration of the cells, the size of each cell, and the thickness of the connecting elements. Mechanical properties of cellular structures can be established experimentally and confirmed numerically. Special cellular specimens have been designed for uniaxial tensile, bending, compression, shear, and low-cycle fatigue testing. Several variants of cell structures with relative densities ranging from 13 to 45% were considered. Specifically, the present study examined the stress-strain states of cell structures from brands “CobaltChrome MP1” powder compositions obtained by laser synthesis on an industrial 3D printer Concept Laser M2 Cusing Single Laser 400W. Numerical simulations of the tests were carried out by the finite element method. Then, the most rational cellular structures in terms of mass and strength were established on the basis of both real and numerical experiments.

Open-Cell Foam Metal Production and Characterization by Aluminum Solid Mold Investment Casting

2019 ◽  
Author(s):  
Kerem Altug Guler
Keyword(s):  
Investment Casting ◽  
Replication Process ◽  
Open Cell ◽  
Metal Fabrication ◽  
Cell Structures ◽  
Closed Cell ◽  
Small Complex ◽  
Open Cell Foam ◽  
Foam Metal ◽  
Cell Foam

Foam metals can be categorized in two basic classes: open-cell and closed-cell structures, which both have different numerous unique properties. Up to the present, several production processes have been developed for each class. Investment casting is known as a replication process for open-cell foam metal fabrication. Solid mold, which can be evaluated as a subtechnique of the investment casting, is specialized especially for small complex shapes with ultrathin sections. This work is a presentation of aluminum open-cell foam production with solid mold investment casting using two different kinds of patterns. The first one is “burnable,” in which liquid metal directly fills the shape of pattern and the second is “leachable,” in which metal takes the form of intergranular network shape of porous salt preforms.

Technological Exercise of Cell Structure Forming

2017 ◽  
Vol 736 ◽  
pp. 122-126 ◽  
Author(s):  
S.N. Larin ◽  
V.I. Platonov ◽  
G.A. Nuzgdin
Keyword(s):  
Liquid Fuel ◽  
Cell Structure ◽  
Experimental Studies ◽  
Single Layer ◽  
Processing Parameters ◽  
Utilization Factor ◽  
Specific Strength ◽  
Cell Structures ◽  
Critical Strain Rate ◽  
Material Utilization

Single-layer and multi-layer cell structures are used for manufacturing of shells of liquid fuel tankers, as well as of "dry" shells of products, wings, fairings, etc. However, conventional methods of production by means of milling do not allow achieving the required specific strength. In this connection, diffusion bonding by means of gas pressure and gas forming at specified temperature and speed conditions are extremely important. Studies conducted by authors help model the processes and calculate the necessary processing parameters: pressure, critical strain rate, deformation rate (deformation time). This paper describes the manufacturing technology for these products, in which the solutions are based on theoretical and experimental studies, which provide: an increase in specific strength; reduction in weight of the product; reduction of labor intensity and increase in material utilization factor.

Cell structure and mechanical properties of microcellular PLA foams prepared via autoclave constrained foaming

2020 ◽  
pp. 026248932093032
Author(s):  
Jinwei Chen ◽  
Ling Yang ◽  
Dahua Chen ◽  
Qunshan Mai ◽  
Meigui Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Size ◽  
Cell Structure ◽  
Saturation Pressure ◽  
Tensile Modulus ◽  
Cell Structures ◽  
Wide Range ◽  
The Mean ◽  
Constrained Foaming ◽  
The Relationship

Microcellular polylactic acid (PLA) foams with various cell size and cell morphologies were prepared using supercritical carbon dioxide (sc-CO2) solid-state foaming to investigate the relationship between the cell structure and mechanical properties. Constrained foaming was used and a wide range of cell structures with a constant porosity of ∼75% by tuning saturation pressure (8–24 MPa) was developed. Experiments varying the saturation pressure while holding other variables’ constant show that the mean cell size and the mean cell wall thickness decreased, while the cell density and the open porosity increased with increase of pressure. Tensile modulus of PLA foams decreased with increasing the saturation pressure, but the specific tensile modulus of PLA foams was still 15–80% higher than that of solid PLA. Tensile strength and elongation at break first increased with increasing saturation pressure up to 16 MPa and then decreased with further increasing saturation pressure (20 MPa and 24 MPa) at which opened-cell structure produced. Compressive modulus, compressive strength, and compressive yield stress also followed the same variation trend. The results indicated that not only cell size plays an important role in properties of PLA foams but also cell morphology can influence these properties significantly.

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