The magnetic field generated by a pair of coaxial circular loops is analyzed in order to find the optimum separation between the loops for each value of a prescribed homogeneity. For the maximum heterogeneities considered here, 0.1%, 1%, and 10%, the optimum loop spacing is obtained following a graphical procedure so that the length of the homogeneous field region along the axis is the longest possible. This study is extended to regions near the axis and to the entire region surrounding the center, calculating the loop separation that produces the largest homogeneous volume. The field homogeneity of a pair of "Helmholtz" coaxial conical coils is also investigated to obtain the optimum spacing between the conical coils; the volumes calculated with the desired homogeneity are compared with those obtained with a single pair of optimum coaxial loops. A new arrangement is hereby proposed based on double conical coils with optimum separation between the coils and optimum aperture of the cones. Some of the proposed arrangements are carried out in the laboratory where the experimental results are in good agreement with the theoretical predictions.
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http://dx.doi.org/10.1063/1.5079476 | DOI Listing |
Microsc Res Tech
December 2024
Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, Tucumán, Argentina.
Sperm morphology is considered the best indicator of male fertility. In Neotropical bats, important aspects of sperm morphology have been scantly studied. The aim of the present study was to characterize and compare the sperm morphology and morphometry of Artibeus planirostris and Sturnira erythromos.
View Article and Find Full Text PDFJ Cardiothorac Surg
February 2024
Department of Vascular Surgery, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China.
Purpose: To evaluate the efficacy and safety of selective aneurysmal sac neck-targeted embolization in endovascular aneurysm repair (EVAR) in patients with a hostile neck anatomy (HNA).
Materials And Methods: Between October 2020 and June 2022, patients with an abdominal aortic aneurysm (AAA) and HNA who underwent EVAR with a low-profile stent graft and a selective aneurysmal sac neck-targeted embolization technique were analysed. An HNA was defined by the presence of any of the following parameters: infrarenal neck angulation > 60°; neck length < 15 mm; conical neck; circumferential calcification ≥ 50%; or thrombus ≥ 50%.
Zookeys
August 2023
Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA National Museum of Natural History Washington, DC United States of America.
Black corals (Anthozoa: Antipatharia) are an anthozoan lineage in the class Hexacorallia that occur across a wide range of habitats from the tropics to the poles and from surface waters to depths deeper than 8000 m. A new species of black coral, , collected with a remotely operated vehicle 357 m deep off Puerto Rico is recognized in the family Aphanipathidae. The new species is characterized by very long and loosely coiled primary branches and up to 0.
View Article and Find Full Text PDFFront Robot AI
June 2023
Department of Mechanical Engineering, University of Iowa, Iowa City, IA, United States.
Based on the NASA in-Space Assembled Telescope (iSAT) study (Bulletin of the American Astronomical Society, 2019, 51, 50) which details the design and requirements for a 20-m parabolic in-space telescope, NASA Langley Research Center (LaRC) has been developing structural and robotic solutions to address the needs of building larger in-space assets. One of the structural methods studied involves stackable and collapsible modular solutions to address launch vehicle volume constraints. This solution uses a packing method that stacks struts in a dixie-cup like manner and a chemical composite bonding technique that reduces weight of the structure, adds strength, and offers the ability to de-bond the components for structural modifications.
View Article and Find Full Text PDFSurg Neurol Int
January 2023
Department of Neurosurgery, Ehime Prefectural Niihama Hospital, Niihama City, Ehime, Japan.
Background: Endovascular treatment for a ruptured blister-like aneurysm (BLA) has recently become a hopeful approach. BLAs are usually located on the dorsal wall of the internal carotid artery, whereas one located on the azygos anterior cerebral artery (ACA) is so rare, it has never been reported. We report a case of a ruptured BLA arising at the distal bifurcation of an azygos ACA treated by stent-assisted coil embolization.
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