scholarly journals Novel lightweight open-cell polypropylene foams for filtering hazardous materials

RSC Advances ◽  
2020 ◽  
Vol 10 (30) ◽  
pp. 17694-17701
Author(s):  
Fei Wu ◽  
Pengke Huang ◽  
Haibin Luo ◽  
Jin Wang ◽  
Bin Shen ◽  
...  
Keyword(s):  
Hazardous Materials ◽  
Porous Structures ◽  
Open Cell ◽  
Extrusion Foaming

Lightweight polypropylene foams with similar geometries but different porous structures were prepared as filters for potentially hazardous materials via supercritical CO2 extrusion foaming without the use of harmful reagents and the problems of floating micro-nano fibers.

Characterization of laminar flow in periodic open-cell porous structures

2019 ◽  
Vol 201 ◽  
pp. 397-412 ◽  
Author(s):  
Pedro Jorge ◽  
Miguel A.A. Mendes ◽  
Eric Werzner ◽  
José M.C. Pereira
Keyword(s):  
Laminar Flow ◽  
Porous Structures ◽  
Open Cell

Analysis of variability in additive manufactured open cell porous structures

2017 ◽  
Vol 231 (6) ◽  
pp. 534-546
Author(s):  
Sam Evans ◽  
Eric Jones ◽  
Pete Fox ◽  
Chris Sutcliffe
Keyword(s):  
Porous Material ◽  
Pore Size ◽  
Porous Structures ◽  
Micro Computed Tomography ◽  
Microscopy Imaging ◽  
Geometric Properties ◽  
Open Cell ◽  
Material Thickness ◽  
Cell Structures ◽  
The Mean

In this article, a novel method of analysing build consistency of additively manufactured open cell porous structures is presented. Conventionally, methods such as micro computed tomography or scanning electron microscopy imaging have been applied to the measurement of geometric properties of porous material; however, high costs and low speeds make them unsuitable for analysing high volumes of components. Recent advances in the image-based analysis of open cell structures have opened up the possibility of qualifying variation in manufacturing of porous material. Here, a photogrammetric method of measurement, employing image analysis to extract values for geometric properties, is used to investigate the variation between identically designed porous samples measuring changes in material thickness and pore size, both intra- and inter-build. Following the measurement of 125 samples, intra-build material thickness showed variation of ±12%, and pore size ±4% of the mean measured values across five builds. Inter-build material thickness and pore size showed mean ranges higher than those of intra-build, ±16% and ±6% of the mean material thickness and pore size, respectively. Acquired measurements created baseline variation values and demonstrated techniques suitable for tracking build deviation and inspecting additively manufactured porous structures to indicate unwanted process fluctuations.

Extrusion Foaming System for Fabricating Open-Cell Structure of Low Density Polyethylene (LDPE)

2012 ◽  
Vol 550-553 ◽  
pp. 891-896
Author(s):  
Dong Won Jung ◽  
Dong Hong Kim ◽  
Bong Chun Kim ◽  
E. K. Lee ◽  
J. C. Park ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Cell Structure ◽  
Processing Parameters ◽  
Expansion Ratio ◽  
Sem Analysis ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Cell Content ◽  
Open Cell ◽  
Extrusion Foaming

Low Density Polyethylene (LDPE) foam of open-cell type was manufactured through extrusion foaming system using a physical blowing agent for the application of sound absorption. For the purpose of enhancing the open cell content, salt powder was blended with LDPE changing the content and particle size. Scanning electron microscopy (SEM) analysis was carried out in order to observe the cell morphology. With a view to characterizing the open-cell structure, open-cell content and expansion ratio were measured with extruded foams. Finally the effect of formulation and processing parameters on cell morphology was investigated.

scholarly journals Photogrammetric analysis of additive manufactured metallic open cell porous structures

2018 ◽  
Vol 24 (8) ◽  
pp. 1380-1391 ◽  
Author(s):  
Samuel Evans ◽  
Eric Jones ◽  
Peter Fox ◽  
Chris Sutcliffe
Keyword(s):  
Pore Size ◽  
Low Cost ◽  
High Volume ◽  
Porous Structures ◽  
Micro Computed Tomography ◽  
Open Cell ◽  
Content Type ◽  
Material Thickness ◽  
Computed Tomography Scanning ◽  
Photogrammetric Method

PurposeThis paper aims to introduce a novel method for the analysis of open cell porous components fabricated by laser-based powder bed metal additive manufacturing (AM) for the purpose of quality control. This method uses photogrammetric analysis, the extraction of geometric information from an image through the use of algorithms. By applying this technique to porous AM components, a rapid, low-cost inspection of geometric properties such as material thickness and pore size is achieved. Such measurements take on greater importance, as the production of porous additive manufactured orthopaedic devices increases in number, causing other, slower and more expensive methods of analysis to become impractical.Design/methodology/approachHere the development of the photogrammetric method is discussed and compared to standard techniques including scanning electron microscopy, micro computed tomography scanning and the recently developed focus variation (FV) imaging. The system is also validated against test graticules and simple wire geometries of known size, prior to the more complex orthopaedic structures.FindingsThe photogrammetric method shows an ability to analyse the variability in build fidelity of AM porous structures for use in inspection purposes to compare component properties. While measured values for material thickness and pore size differed from those of other techniques, the new photogrammetric technique demonstrated a low deviation when repeating measurements, and was able to analyse components at a much faster rate and lower cost than the competing systems, with less requirement for specific expertise or training.Originality/valueThe advantages demonstrated by the image-based technique described indicate the system to be suitable for implementation as a means of in-line process control for quality and inspection applications, particularly for high-volume production where existing methods would be impractical.

scholarly journals Thermo-Responsive Shape Memory Effect and Conversion of Porous Structure in a Polyvinyl Chloride Foam

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2025
Author(s):  
Tao Xi Wang ◽  
Lu Lu Chang ◽  
Yun Hui Geng ◽  
Xing Shen
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Polyvinyl Chloride ◽  
Shape Recovery ◽  
Porous Structures ◽  
Cell Level ◽  
Open Cell ◽  
Optical Images ◽  
Closed Cell

In this paper, a thermo-responsive shape memory effect in a polyvinyl chloride thermoset foam is characterized. Excellent shape recovery performance is observed in foam samples programmed both at room temperature and above their transition temperature. The conversion of porous structures in the foam from closed-cell to open-cell after a shape memory effect cycle is revealed via a series of specially designed oil-dripping experiments and optical images of the micro pores. Programming the strain higher than 20% results in an apparent increase in open-cell level, whereas programming temperatures have almost no influence.

Open-Cell Metallic Porous Materials Obtained Through Space Holders—Part I: Production Methods. A Review

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
Lenko Stanev ◽  
Mihail Kolev ◽  
Boris Drenchev ◽  
Ludmil Drenchev
Keyword(s):  
Liquid Phase ◽  
Porous Materials ◽  
Inorganic Materials ◽  
Structure Parameters ◽  
Porous Structures ◽  
Structural Elements ◽  
Open Cell ◽  
Production Methods ◽  
Flexible Application ◽  
Removal Technique

This article presents a review of current methods for production of metallic open-cell porous materials through space holders. The methods are divided into two major groups: on the basis of sintering and using liquid phase processing. Details about technologies are given, and their relations to structure parameters of obtained materials are discussed. Methods with 11 different space holders are described. The space holders could be metallic or nonmetallic (organic and inorganic) materials which could be leached or burned depending on removal technique. It is concluded that the flexible application of different space holders offers opportunities for obtaining large variety of metallic porous structures. A new line of development should be elaboration of complex techniques for production of porous structure with graded pore size and/or porosity which will meet various engineering requirements and will open new possibilities for applications as functional and structural elements. The next part of this work is devoted to the structure, the properties, and application of the open-cells porous materials obtained through space holders.

155. Emergency Management of Patients Contaminated with Hazardous Materials

1999 ◽  
Author(s):  
K.A. Packard ◽  
N. Moss ◽  
J. McCarthy ◽  
M. Jay
Keyword(s):  
Emergency Management ◽  
Hazardous Materials
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