1,982 research outputs found

    Aw-Aw-Tam Indian Nights: Being the Myths and Legends of the Pimas of Arizona

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    This is a book from the beginning of the twentieth century about the folklore of the Pima Indians and the skills they have attained in order to survive. The tales here are consistent with other Native American mythology of the Southwestern United States. According to the book, “these were stories which he used to hear his father tell, they being handed down from father to son, and that when he was little he did not pay much attention, but when he grew older he determined to learn them, and asked his father to teach him, which his father did, and now he knew them all.

    Influence of temperature and sliding speed on the subsurface microstructure evolution of EN AW-6060 under sticking friction conditions

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    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conference Proceedings 1896, 140012 (2017) and may be found at https://doi.org/10.1063/1.5008168.The microstructure evolution of the friction boundary layer of the aluminum alloy EN AW-6060 was investigated. Sticking friction tests at different temperatures and sliding speeds were carried out. A severe deformation below the friction surface was observed by means of LOM and EBSD mapping. Thus, the thickness variation and the grain structure of the high deformation zone could be described. Fibrous structure was observed at 300 °C and 400 °C, while equiaxed grains with high misorientation angle (>15°) were generated at higher temperatures. Additionally, abnormal grain growth and coarse grains were detected at high sliding speeds (10 mm/s, 42 mm/s) at 450°C and 500 °C respectively

    Author-Suggested, Weighted Citation Index: A Novel Approach for Determining the Contribution of Individual Researchers

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    A novel scientometric index, named ‘author-suggested, weighted citation index’ (Aw-index) is proposed to indicate the scientific contribution of any individual researcher. For calculation of the Aw-index, it is suggested that during the submission of a scholarly article, the corresponding author would provide a statement, agreed upon by all the authors, containing weightage factors against each author of the article. The author who contributed more to the article would secure a higher weightage factor. The summation of the weightage factors of all the authors of an article should be unity. The citation points a researcher receives from a scholarly publication is the product of his/her weightage factor for that article and the total number of citations of the article. The Aw-index of any individual researcher is the summation of the citation points he/she receives for all his/her publications as an author. The Aw-index provides the opportunity to the group of authors of a multi-authored article to determine the quantum of partial citations to be attributed to each of them. Through an illustrative example, a comparison of the proposed index with the major scientometric indexes is presented to highlight the advantages of the Aw-index

    Influence of Process Parameters on the Quality of Aluminium Alloy EN AW 7075 Using Selective Laser Melting (SLM)

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    AbstractSelective laser melting (SLM) is an additive manufacturing process, forming the desired geometry by selective layer fusion of powder material. Unlike conventional manufacturing processes, highly complex parts can be manufactured with high accuracy and little post processing. Currently, different steel, aluminium, titanium and nickel-based alloys have been successfully processed; however, high strength aluminium alloy EN AW 7075 has not been processed with satisfying quality. The main focus of the investigation is to develop the SLM process for the wide used aluminium alloy EN AW 7075. Before process development, the gas-atomized powder material was characterized in terms of statistical distribution: size and shape. A wide range of process parameters were selected to optimize the process in terms of optimum volume density. The investigations resulted in a relative density of over 99%. However, all laser-melted parts exhibit hot cracks which typically appear in aluminium alloy EN AW 7075 during the welding process. Furthermore the influence of processing parameters on the chemical composition of the selected alloy was determined

    Zhedanov's Algebra AW(3) and the Double Affine Hecke Algebra in the Rank One Case. II. The Spherical Subalgebra

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    This paper builds on the previous paper by the author, where a relationship between Zhedanov's algebra AW(3) and the double affine Hecke algebra (DAHA) corresponding to the Askey-Wilson polynomials was established. It is shown here that the spherical subalgebra of this DAHA is isomorphic to AW(3) with an additional relation that the Casimir operator equals an explicit constant. A similar result with q-shifted parameters holds for the antispherical subalgebra. Some theorems on centralizers and centers for the algebras under consideration will finally be proved as corollaries of the characterization of the spherical and antispherical subalgebra

    Automating the determination of wave speed using the pu-loop method

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    The PU-loop (pressure-velocity loop) is a method for determining wave speed and relies on the linear relationship between the pressure and velocity in the absence of reflected waves. This linearity of the PU-loop during early systole, which is directly related to wave speed, has always been established by eye. This paper presents a new technique that establishes this linearity and thus determining wave speed online. Pressure and flow were measured in the ascending aorta of 11 anesthetised dogs. The slope of the PU-loop, indicating wave speed was determined by eye and by using the new technique. The difference between the slopes of the two methods is in the order of 3%. The new technique is convenient and allows for the online assessment of wave speed, which could be used as a bedside tool for the assessment of arterial compliance
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