Fiber Length Attrition in Additive Manufacturing

Chopped carbon fibers are used as reinforcements in thermoplastics, but the viscous shear forces that arise in melt-processing reduces the fiber length well below its critical length resulting in only moderate strength and stiffness gains compared to the neat resin. This research project aimed to experimentally determine the effect of the melt–flow portion of a single-screw- extrusion process on carbon fiber length attrition in isolation from the immediately preceding screw–plastication step that is responsible for most of the heat needed for melting. Carbon fibers with an initial length of 2 mm were stirred into 5,000 centipoise and 10,000 centipoise silicone oils at a fiber volume fraction of 10\%. Each suspension was passed through a single–screw–extruder under the same conditions and the resultant fiber length distributions were compared for absolute and relative amounts of length attrition. Silicone oil suspensions of fibers were shown to be a viable method of determining the effect of the melt–phase of the extrusion process.... [RESULTS REDACTED

Letter by Jose Chapiro to Earl Clement Davis

There is a substantial expression of gratitude for Earl Davis in the Acknowledgments section of José Chapiro\u27s 1947 book Thoughts for Each Day selected from the writings of William Ellery Channing: “Finally, I am particularly gratified to inscribe here the name of Earl C. Davis, the sage of Petersham, Massachusetts, and a distinguished citizen of the Free State of William Ellery Channing. A tireless reader, he is also a perpetual student of that ‘gay science’—the word is Nietzsche’s—in which scholarship and life complement and fertilize each other. Earl C. Davis cultivates it with the same joy and earnestness of purpose with which he cultivates the flowers and vegetables in his garden. Above all, he has an uncommon knowledge of the realm of Channing. He has roamed through it many times and in every direction. He knows its apparent beauties and hidden charms, its peaks and its depths; and its sunny landscapes still remain the favorite goal of his spiritual excursions and rambles. Earl C. Davis often served me as guide, as counsellor, and as a source from which I could draw valuable information that it would have been difficult to find elsewhere. I thank him.” (p. 440). The author and his wife Elisabeth gave a copy of the newly published book to Earl and Annie on December 21, 1947. Their gift came with a letter and was inscribed. Both the letter and inscription are available here. Evidently, Earl Davis was not entirely comfortable with this acknowledgement, for there is mention of it in a letter from John Haynes Holmes (1879-1964), who was a fellow student with Earl Davis at the Harvard Divinity School (both graduated in 1904). In a letter to Earl Davis dated April 27, 1949, Holmes writes, “I am amused by what you write of your embarrassment in the matter of Chapiro’s reference to you in the Channing book. I think you are over-sensitive on this point. The tribute to you is wholly deserved, and in the proper place. It would be a real loss to have this gracious tribute of Chapiro to your sympathy and help removed from later editions. And this same opinion of mine applies to Mrs. Hapgood as well as to yourself.” There is some uncertainty as to the dates. The letter is dated December 21, 1947. The book’s publication date is 1948, which is consistent with a early edition gift for Christmas, 1947. The inscription in the book, however, says “Christmas, 1948,” and offers “heartiest wishes for 1949.” The primary downloadable document contains both the original letter followed by the transcription. The three supplementary files are the inscription, the original letter, and the transcription, respectively. The bottom of each item page also features the primary document as an embedded pdf for browsing. Transcription by Davis Baird. Item description based off writing and context provided by Davis Baird.https://commons.clarku.edu/petersham_manuscripts/1007/thumbnail.jp

Traveling wave solutions for non-Newtonian foam flow in porous media

The injection and in-situ generation of foam in porous media successfully control gas mobility and improve the fluids' sweep efficiency inside porous media. Mathematical models describing this problem use two phases, foamed gas and fluid, and usually have a term for foam generation and destruction. Moreover, the non-Newtonian foam behavior is frequently modeled using the Hirasaki and Lawson's formula for foamed gas viscosity. In this paper, we detail how the traveling wave analysis can be used to estimate the propagation profiles and velocity for a range of non-Newtonian foam models in porous media at constant total superficial flow velocity. We reformulate Hirasaki and Lawson's formula in an explicit form allowing us to find traveling wave solutions for the non-Newtonian Linear Kinetic model. Comparing the solution with the one for the Newtonian version, allows us to analyze qualitatively and quantitatively the rheology of the foam flow in porous media.Comment: 20 pages, 7 figure

Ti paate Santa marianu chumu Chachillaa kule kitaa juntsanu pipi nemu deeve

La presente investigación se enmarca a la confección de la canoa como medio de transporte de la nacionalidad chachi, este proceso gracias a las bondades de la naturaleza han perfeccionado un sin número de manifestaciones y valores culturales desarrollando así la cultura material. Entre aquellos saberes más notables es el desarrollo y progreso de los medios de transporte, como elemento importante de la cosmovisión y saber cosmogónico del conocimiento propio de la cultura Chachi. La construcción de la la canoa no se conserva la originalidad ancestral ya que la influencia del desarrollo del medio de transporte como lancha, botes hace que se adapte al ritmo de vida de la sociedad moderma. Es evidente que, después de la investigación se haya rescatado, la valorización de algunos elementos culturales y en lo posterior esto forme parte del currículo en el proceso enseñanza –aprendizaje de los niños y adolescentes chachi Esta investigación ha dado la oportunidad de registrar los elementos culturales de las técnicas de confección de la canoa como medio de transporte de la nacionalidad Chachi, y se constatado que los elementos, no incide en la desvalorización de la elaboración de la canoa tradicional, sino más, bien, se ha constatado la falta de difusión y fortalecimiento de estos elementos culturalesConfección de la canoa, nacionalidad chachi, valores culturales, cosmovisión, saber cosmogónico, ancestral, ritmo de vida, valorización, técnicas de confección, desvalorizaciónLicenciado en Ciencias de la Educación con mención en Educación Intercultural BilingüeCuenc

Coherent states for the hydrogen atom

We construct a system of coherent states for the hydrogen atom that is expressed in terms of elementary functions. Unlike to the previous attempts in this direction, this system possesses the properties equivalent to the most of those for the harmonic oscillator, with modifications due to the character of the problem.Comment: 6 pages, LATEX, using ioplppt.sty and iopfts.sty. v.2: some misprints are corrected. To appear in J.Phys.

t(9;14)(q33;q32) IGH/LHX2

Short Communication on t(9;14)(q33;q32) IGH/LHX2, with data on clinics, and the genes implicated