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Journal ArticleDOI

Powder flowability and density ratios: the impact of granules packing

01 Jul 2003-Chemical Engineering Science (Pergamon)-Vol. 58, Iss: 13, pp 2857-2874
TL;DR: In this paper, a new flowability criterion based on a novel technique to determine a high packing density was proposed, which is more sensitive to differences in flowability, as quantified by the repose angle.
About: This article is published in Chemical Engineering Science.The article was published on 2003-07-01. It has received 222 citations till now. The article focuses on the topics: Angle of repose.
Citations
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Journal ArticleDOI
TL;DR: A review of the emerging research on additive manufacturing of metallic materials is provided in this article, which provides a comprehensive overview of the physical processes and the underlying science of metallurgical structure and properties of the deposited parts.

4,192 citations


Cites methods from "Powder flowability and density rati..."

  • ...Flowability of the powders is measured by Hall flow meter [43,44]....

    [...]

Journal ArticleDOI
TL;DR: In this article, a review of additive manufacturing (AM) techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid-state precipitation, mechanical properties and post-processing metallurgy.
Abstract: Additive manufacturing (AM), widely known as 3D printing, is a method of manufacturing that forms parts from powder, wire or sheets in a process that proceeds layer by layer. Many techniques (using many different names) have been developed to accomplish this via melting or solid-state joining. In this review, these techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid-state precipitation, mechanical properties and post-processing metallurgy. The various metal AM techniques are compared, with analysis of the strengths and limitations of each. Only a few alloys have been developed for commercial production, but recent efforts are presented as a path for the ongoing development of new materials for AM processes.

1,713 citations


Cites background from "Powder flowability and density rati..."

  • ...Further information on the standards associatedwith quantifying powder characteristics and the details of powder science are well described elsewhere.(52) The quality of powder is directly related to the production technique....

    [...]

Journal ArticleDOI
06 Apr 2016
TL;DR: Marshall has unique expertise in leveraging new digital tools, 3D printing, and other advanced manufacturing technologies and applying them to propulsion systems design and other aerospace materials to meet NASA mission and industry needs.
Abstract: Propulsion system development requires new, more affordable manufacturing techniques and technologies in a constrained budget environment, while future in-space applications will require in-space manufacturing and assembly of parts and systems. Marshall is advancing cuttingedge commercial capabilities in additive and digital manufacturing and applying them to aerospace challenges. The Center is developing the standards by which new manufacturing processes and parts will be tested and qualified. Rapidly evolving digital tools, such as additive manufacturing, are the leading edge of a revolution in the design and manufacture of space systems that enables rapid prototyping and reduces production times. Marshall has unique expertise in leveraging new digital tools, 3D printing, and other advanced manufacturing technologies and applying them to propulsion systems design and other aerospace materials to meet NASA mission and industry needs. Marshall is helping establish the standards and qualifications “from art to part” for the use of these advanced techniques and the parts produced using them in aerospace or elsewhere in the U.S. industrial base.

481 citations

Journal ArticleDOI
TL;DR: The physics of granular materials in ambient gases is governed by interparticle forces, gas-particle interaction, geometry of particle positions and geometry of particles contacts as mentioned in this paper, which are strongly dependent on the external forces, boundary conditions and on the assembling procedure.
Abstract: Memento, homo, qui pulvis est et pulverem reverteris. Genesis 3 Polvos seran, mas polvo enamorado. Francisco de Quevedo The physics of granular materials in ambient gases is governed by interparticle forces, gas–particle interaction, geometry of particle positions and geometry of particle contacts. At low consolidations these are strongly dependent on the external forces, boundary conditions and on the assembling procedure. For dry fine powders of micron and sub-micron particle size interparticle attractive forces are typically much higher than particle weight, and particles tend to aggregate. Because of this, cohesive powders fracture before breaking, flow and avalanche in coherent blocks much larger than the particle size. Similarly the drag force for micron sized particles is large compared to their weight for velocities as low as 1 mm/s. Due to this extreme sensitivity to interstitial gas flow, powders transit directly from plastic dense flows to fluidization without passing through collisional re...

450 citations

Journal ArticleDOI
TL;DR: In this paper, the magnetic assisted impaction coater (MAIC) and the hybridizer (HB) were used to coat cornstarch powder with different size silica particles and the improvement in flowability was determined from angle of repose measurements using a Hosokawa powder tester.

393 citations

References
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Book ChapterDOI
01 Jan 1981

5,742 citations

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5,059 citations

Book
01 Nov 1992
TL;DR: In this article, Coulomb's method of wedges and differential slices were used to determine the stress and strain rate of Coulomb material, and the conical yield function was used to predict mass flow rate.
Abstract: 1. Introduction 2. The analysis of stress and strain rate 3. The ideal Coulomb material 4. Coulomb's method of wedges 5. The method of differential slices 6. Determination of physical properties 7. Exact stress analysis 8. Velocity distributions 9. The conical yield function 10. The prediction of mass flow rate Problems Appendices Index.

953 citations

Journal ArticleDOI
TL;DR: In this article, the dilatancy of media composed of rigid particles in contact is studied and an experimental illustration of the effect of the dilated media on the density of the particles is provided.
Abstract: (1885). LVII. On the dilatancy of media composed of rigid particles in contact. With experimental illustrations. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 20, No. 127, pp. 469-481.

840 citations