Cast Plastic Research Articles

Predicting Residual Stresses due to Solidification in Cast Plastics

A method is developed for the quantitative prediction of thermally induced residual stresses in polymeric materials. During processing, when the polymeric material is cooling down from an elevated temperature, to room temperature, a strain becomes 'frozen-in' the material. Different cooling processes will cause different amounts of the strain to become frozen-in. The residual stresses are then just a material response to the frozen-in strains at a uniform room temperature, well after processing. A link between thermal history and frozen-in strains is found to be the 'residual' temperature field. The thermo-mechanical response of the material to the applied residual temperature field is identical to the response to frozen-in strains only. By knowing the residual temperature field, the residual stress problem can be considered as a thermal stress problem, which can be solved using various commercial numerical packages. The numerical algorithm for determining the residual temperature field is also presented. It accommodates various elements of the Finite Volume mesh topology as the Finite Volume method is used to carry out the thermo-mechanical analysis. The procedure includes tracking integration paths always orthogonal to the solidification front at any point and numerical integration of frozen-in temperature gradients along them. The application of the method is illustrated by predicting residual stresses in a polymeric plate subjected to controlled cooling conditions.

Melt cast elastomeric PBX — processing and properties overview

Thermoplastic, rubbery binder systems are being developed for melt cast plastic bonded explosives. These materials are tailored for the existing Navy i In the event of rapid mobilization, present-day curable PBX's could not be processed in-house in large volume. Production would revert to older melt ca Melt cast binder systems will be described and the processability and physical properties of the PBX compositions will be presented.

Three-dimensional myocardial and ventricular shape: a surface representation.

To date, a detailed three-dimensional (3D) analysis of cardiac shape and size has not been available. Accordingly, we developed a method for such an analysis using sectioned hearts and a computer-based 3D description of the epi- and endocardial surfaces of the left and right ventricles (LV and RV) and the interventricular septum. The accuracy of this analysis as a function of section thickness (hs) was evaluated and reference axes for the LV, RV, and myocardium determined in eight canine hearts. After diastolic arrest, the RV, LV, and their atria were fixed in formaldehyde solution at pressures of 6 and 12 cmH2O, respectively. The hearts were then cast (plastic or gelatin) and sectioned, and the surfaces were digitized. We found that 1) accurate 3D computer reconstructions and computed volumes of the LV, RV, and myocardium were obtained then hs less than or equal to 5 mm, 2) the apex-to-base circumference and cross-sectional area relations could be approximated provided hs less than 10 mm, and 3) the section centers of gravity for the LV, RV, and myocardium defined three distinct vertical lines. Thus, an accurate description of 3D configuration is obtainable by a 5-mm section thickness. The centers of gravity provide a set of geometrical references for the study of shape in normal and diseased hearts.

Urethane Cast Plastics in Furniture

Urethane Cast Plastics in Furniture

Cast Plastic Laser Pump Cavities

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text Harold A. Daw and Jerald R. Izatt, "Cast Plastic Laser Pump Cavities," Appl. Opt. 3, 984-985 (1964) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Specially cast plastic scintillators developed by argonne laboratory

Specially cast plastic scintillators developed by argonne laboratory

Cast Plastics from 2-Furaldehyde

Cast Plastics from 2-Furaldehyde

Oxygen Absorption by Cast Plastic Films

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxygen Absorption by Cast Plastic FilmsJ. W. WestwaterCite this: Ind. Eng. Chem. 1948, 40, 8, 1494–1500Publication Date (Print):August 1, 1948Publication History Published online1 May 2002Published inissue 1 August 1948https://doi.org/10.1021/ie50464a034© American Chemical SocietyRIGHTS & PERMISSIONSArticle Views39Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (909 KB) Get e-Alerts

Crystals and crystal lenses.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Crystals and crystal lenses. Henroteau, F. Abstract M any materials have been used for the making of lenses. Cood optical glass, especially in large pieces, is expensive to produce and in aspherical lenses, such as Schmidt correctors, is long and tedious to grind and to polish. Recently plastics have been used but they are subject to strains and are easily scratched and deformed. More- over, cast plastic lenses could never have the accuracy of glass ones for astronomical purposes, because having to be made at fairly high temperatures, they are somewhat distorted and have a slightly different refractive index after cooling. Transparent crystals, grown to any size, are absolutely homogenous and have constant refractive indices. Many crystals, moreover, are transparent in a much wider range of the spectrum than glass and can be used for many applications in the infrared and in the ultraviolet. Beautiful crystals of sodium chloride, potassium bromide, lithium fluoride and other chemicals crystallizing in the cubic system have been produced by special methods involving fusion followed by slow cooling. Methods are being developed by the writer and his associates in the laboratories of the Farnsworth Television and Radio Corporation, in Fort Wayne, Indiana, to produce crystals from solutions in water. A large, single crystal of ammonium alum, weighing more than two kilograms, was recently obtained and could have been develo~ed by accretion to wei~h much more than that. Also an apparatus has just been completed by means of which lenses can be made out of soluble cubic crystals, using controlled dissolution. The principle of this apparatus is the following: A negative form of the lens surface, spherical, aspherical or even skew is made out of insoluble material. This form is cooled and moist air is blown toward it with the result that a very thin film of moisture, perhaps one micron thick, is formed over it. A crystal, say of sodium chloride, attached to a rigid stem which moves back and forth by means of a motor is brought into contact with this film and then removed. A thickness of the order of one micron is dissolved where the crystal was in contact with the film. The dissolved part is then blown off by a strong blast of air which also removes the rest of the original film on the form. A new film is then produced on the form and the operation just described is repeated again and again until the outside surface of the crystal has taken the exact shape of the form. Farnsworth Television and Radio Corporation, Fort Wayne, Ind. Publication: The Astronomical Journal Pub Date: June 1945 DOI: 10.1086/105849 Bibcode: 1945AJ.....51..122H full text sources Publisher | ADS |