323,520 research outputs found
Increasing output power of electromagnetic vibration energy harvesters using improved Halbach arrays
No full textThis paper extends previously published studies into the performance of Halbach arrays for electromagnetic vibration energy harvesting. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field to almost zero on the other side. This arrangement can improve electromagnetic coupling in a limited space. Previous research showed that although the Halbach array has higher magnetic field density compared to normal magnet layouts, its magnetic flux change rate is not necessarily high. Thus, output powers of energy harvesters with standard Halbach arrays are not always greater than those with normal magnet layouts. Two improvements to the Halbach arrays that lead to increased output power of electromagnetic vibration energy harvesters are presented in this paper. Test results showed that the proposed improved Halbach arrays can increase the output power of energy harvesters by a factor of seven compared to the standard Halbach array
Electromagnetic vibration energy harvesting using an improved Halbach array
No full textThis paper reports an electromagnetic vibration energy harvester using an improved Halbach array. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field on the other side to almost zero. Previous research showed that although the Halbach array has higher magnetic field density compared to normal magnet layouts, its magnetic flux gradient is not as high. Thus, output powers of energy harvesters with Halbach arrays were found to be less than those with normal magnet layouts. This paper proposes an improved Halbach array that achieves both high magnetic field strength and magnetic flux gradient. Test results showed that the improved Halbach array can increase the output power of energy harvesters by a factor of seven compared to the previous Halbach design and by a factor of 1.5 compared to the normal configuration
Vibration energy harvesting using the Halbach array
No full textThis paper studies the feasibility of vibration energy harvesting using a Halbach array. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field to almost zero on the other side. This arrangement can improve electromagnetic coupling in a limited space. The Halbach array offers an advantage over conventional layouts of magnets in terms of its concentrated magnetic field and low-profile structure, which helps improve the output power of electromagnetic energy harvesters while minimizing their size. Another benefit of the Halbach array is that due to the existence of an almost-zero magnetic field zone, electronic components can be placed close to the energy harvester without any chance of interference, which can potentially reduce the overall size of a self-powered device. The first reported example of a low-profile, planar electromagnetic vibration energy harvester utilizing a Halbach array was built and tested. Results were compared to ones for energy harvesters with conventional magnet layouts. By comparison, it is concluded that although energy harvesters with a Halbach array can have higher magnetic field density, a higher output power requires careful design in order to achieve the maximum magnetic flux gradient
Marriner S. Eccles correspondence related to Eccles quotations [07]
No full textCorrespondence from 1965 through 1967 between Marriner S. Eccles and friends, associates, and publishers who sent him published citations of and references to Mr. Eccles. Correspondents included economics author Irving S. Michelman; Hugh S. Norton, professor of economics at the University of South Carolina; and economist Eliot Janeway
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
The astrochemical observatory: Computational and theoretical focus on molecular chirality changing torsions around O – O and S – S bonds
No full textThe observation of hydrogen peroxide in the interstellar medium represents a remarkable discovery for the astrochemistry community. The prototypical role that this molecule, arguably the simplest chiral molecule, plays in the evolution of life in biospheres, is related to the chirality change transitions associated with the torsional motions around the O - O and the S - S bonds. In this paper, we present an overview on the state-of-art of possible experiments to demonstrate chiral effects discrimination and computational tools applied to peroxides and persulfides
Scientometric Portrait of Nobel Laureate S. Chandrasekhar
No full textScientometric analysis of the publications productivity of Nobel Laureate S. Chandrasekhar is documented
Band Alignment and Electrical Investigations of Ultra-Thin Al2O3 on Si by E-beam Evaporation
No full textThe continuous downscaling leads the search of high-gate dielectrics. The films amorphous in nature offered good mechanical flexibility, smooth surfaces and better uniformity associated with low leakage current density. In this work, 16 nm thick amorphous Al2O3 films on silicon substrate are fabricated by E-beam evaporation. The high value of refractive index (1.76) extracted from ellipsometry analysis directs the deposition of compact film. The AFM analysis reveal a flat surface with small RMS surface roughness 1.5 angstrom. The band gap is extracted from O-1s electron loss spectra and was found 6.7 eV and band alignment of Al2O3/Si is derived from the UPS measurements. The films are incorporated in Metal Insulator -Semiconductor (MIS) capacitor to perform the electrical measurement. The flat band voltage (V-FB), dielectric constant () and oxide trapped charges (Q(ot)) extracted from high frequency (1 MHz) C-V curve are - 0.4 V, 8.4 and 2 x 10(11) cm(-2), respectively. The small flat band voltage - 0.4 V, narrow hysteresis and very little frequency dispersion suggest an exceptional good Al2O3/Si interface with small quantity of trapped charges in the oxide. The leakage current density was 4.27 x 10(-8) A/cm(2) at 1 V. The moderate dielectric constant and low leakage current density with ultra-smooth surface is quite useful towards its application in future CMOS and memory devices
Model based defect characterization in composites
No full textWork is reported on model-based defect characterization in CFRP composites. The work utilizes computational models of the interaction of NDE probing energy fields (ultrasound and thermography), to determine 1) the measured signal dependence on material and defect properties (forward problem), and 2) an assessment of performance-critical defect properties from analysis of measured NDE signals (inverse problem). Work is reported on model implementation for inspection of CFRP laminates containing multi-ply impact-induced delamination, with application in this paper focusing on ultrasound. A companion paper in these proceedings summarizes corresponding activity in thermography. Inversion of ultrasound data is demonstrated showing the quantitative extraction of damage properties.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Roberts, R., and S. Holland. "Model based defect characterization in composites." In AIP Conference Proceedings, vol. 1806, no. 1, p. 090015. AIP Publishing LLC, 2017, and may be found at
DOI: 10.1063/1.4974659.
Copyright 2017 Author(s).
Posted with permission
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