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Metallic Rod (metallic + rod)

Distribution by Scientific Domains
Engineering75%

Selected Abstracts

More stabilized triple-band antenna with a rolled radiating arm and a metallic rod for mobile applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009
Xingyu Zhang
Abstract In this article, a compact design of a flexible planar inverted-F antenna (PIFA) is proposed for triple-band (GSM/DCS/PCS) mobile phone application. The main radiating element of the antenna, which generates the GSM and DCS resonant modes, is printed on a flexible printed circuit board (FPCB) and rolled in a form of cylinder. To improve the construction stability of the antenna, a metallic rod is inserted into the centre of the rolled antenna. The metallic rod acting as a parasitic element of the antenna also generates the PCS resonant mode. The antenna prototype was fabricated and measured. Good agreement between the measurement and simulation results is obtained. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 891,894, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24197 [source]

Surgical correction of scoliosis: Numerical analysis and optimization of the procedure

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 9 2010
J. F. Aguilar Madeira
Abstract A previously developed model is used to numerically simulate real clinical cases of the surgical correction of scoliosis. This model consists of one-dimensional finite elements with spatial deformation in which (i) the column is represented by its axis; (ii) the vertebrae are assumed to be rigid; and (iii) the deformability of the column is concentrated in springs that connect the successive rigid elements. The metallic rods used for the surgical correction are modeled by beam elements with linear elastic behavior. To obtain the forces at the connections between the metallic rods and the vertebrae geometrically, non-linear finite element analyses are performed. The tightening sequence determines the magnitude of the forces applied to the patient column, and it is desirable to keep those forces as small as possible. In this study, a Genetic Algorithm optimization is applied to this model in order to determine the sequence that minimizes the corrective forces applied during the surgery. This amounts to find the optimal permutation of integers 1, ,, n, n being the number of vertebrae involved. As such, we are faced with a combinatorial optimization problem isomorph to the Traveling Salesman Problem. The fitness evaluation requires one computing intensive Finite Element Analysis per candidate solution and, thus, a parallel implementation of the Genetic Algorithm is developed. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Superspace description of the modulated structure of the metal-salt-hybrid Bi7,,,,Ni2Br5,,,2, (, = 1/9)

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2009
B. Wahl
The compound Bi7,,,,Ni2Br5,,,2, = (Bi3Ni)2[Bi1,,,,Br4]Br1,,2, (, = 1/9) is a sub-bromide of the intermetallic phase Bi3Ni. Its crystal structure contains metallic rods, [Bi3Ni], which are embedded in a salt-like matrix of bromido-bismuthate(III) and bromide anions. The non-stoichiometry originates from the variation of the number n of trans edge-sharing octahedra in the [BinBr4n,+,2](n,+,2), oligomers (3 ,n, 5), as well as from vacancies on the sites of the isolated Br atoms. The simplified structure is described in the orthorhombic space group Cmcm with a = 4.0660,(4), b = 23.305,(3), c = 17.130,(2),Å. It shows a statistical distribution of vacancies and orientational disorder of the concatenated octahedra. By choosing the modulation vector q = a*/9 + b*/2, the additional weak reflections of the diffraction pattern can be indexed. In the [3,+,1]-dimensional superspace group Pmnm(,½0)000, an ordered structure model is achieved. The modulated crystal structure bears a strong resemblance to the somewhat higher oxidized sub-bromide Bi7,,,,Ni2Br5 (, = 1/9). [source]