15,519 research outputs found
Stacking the Equiangular Spiral
We present an algorithm that adapts the mature Stack and Draw (SaD) methodology for fabricating the exotic Equiangular Spiral Photonic Crystal Fiber. (ES-PCF) The principle of Steiner chains and circle packing is exploited to obtain a non-hexagonal design using a stacking procedure based on Hexagonal Close Packing. The optical properties of the proposed structure are promising for SuperContinuum Generation. This approach could make accessible not only the equiangular spiral but also other quasi-crystal PCF through SaD
Evaluation of electric and magnetic fields distribution and SAR induced in 3D models of water containers by radiofrequency radiation using FDTD and FEM simulation techniques
In this study, two software packages using different numerical techniques
FEKO 6.3 with Finite-Element Method (FEM) and XFDTD 7 with Finite Difference
Time Domain Method (FDTD) were used to assess exposure of 3D models of square,
rectangular, and pyramidal shaped water containers to electromagnetic waves at
300, 900, and 2400 MHz frequencies. Using the FEM simulation technique, the
peak electric field of 25, 4.5, and 2 V/m at 300 MHz and 15.75, 1.5, and 1.75
V/m at 900 MHz were observed in pyramidal, rectangular, and square shaped 3D
container models, respectively. The FDTD simulation method confirmed a peak
electric field of 12.782, 10.907, and 10.625 V/m at 2400 MHz in the pyramidal,
square, and rectangular shaped 3D models, respectively. The study demonstrated
an exceptionally high level of electric field in the water in the two identical
pyramid shaped 3D models analyzed using the two different simulation
techniques. Both FEM and FDTD simulation techniques indicated variations in the
distribution of electric, magnetic fields, and specific absorption rate of
water stored inside the 3D container models. The study successfully
demonstrated that shape and dimensions of 3D models significantly influence the
electric and magnetic fields inside packaged materials; thus, specific
absorption rates in the stored water vary according to the shape and dimensions
of the packaging materials.Comment: 22 pages, 30 figures and 2 table
Recommended from our members
Soft Glass Equiangular Spiral Photonic Crystal Fiber for Supercontinuum Generation
An equiangular spiral photonic crystal fiber (ES-PCF) design in soft glass is presented that has high nonlinearity ( gamma > 5250 W-1 middot km-1 at 1064 nm and gamma > 2150 W-1 middot km-1 at 1550 nm) with a low and flat dispersion (D ~ 0.8 ps/kmmiddotnm and dispersion slope ~ -0.7 ps/km middot nm2 at 1060 nm). The design inspired by nature is characterized by a full-vectorial finite element method. The ES-PCF presented improves over the mode confinement of triangular core designs and dispersion control of conventional hexagonal PCF, combining the advantages of both designs; it can be an excellent candidate for generating supercontinuum pumped at 1.06 mum
Melacak Pemikiran Pembaruan Hukum Islam di Indonesia
Efforts to reform Islamic law, among others, characterized by attempts a review of materials jurisprudence based on the reinterpretation of the texts. This is done because the interpretation of the results given earlier scholars are very thick with the conditions of his time which is certainly different from the situation today. So, the update is needed for the actualization of Islamic teachings relating to the rule of law as contained in the texts. In this case, does not mean changing or leaving the texts of the Qur'an or hadith of the Prophet, but just update the interpretation of the texts to fit with the times. This study is intended to explore some of the basics of thought leaders who are giving birth to a step-by-step reform of Islamic law in Indonesia. Through the identification and exploration of the reformers thought leaders can be affirmed that in some aspects of Islamic law is needed contextualization or development taking into account the social conditions and the times in order to continue dialectic with people's lives and the growing age
High-Dimensional Stochastic Design Optimization by Adaptive-Sparse Polynomial Dimensional Decomposition
This paper presents a novel adaptive-sparse polynomial dimensional
decomposition (PDD) method for stochastic design optimization of complex
systems. The method entails an adaptive-sparse PDD approximation of a
high-dimensional stochastic response for statistical moment and reliability
analyses; a novel integration of the adaptive-sparse PDD approximation and
score functions for estimating the first-order design sensitivities of the
statistical moments and failure probability; and standard gradient-based
optimization algorithms. New analytical formulae are presented for the design
sensitivities that are simultaneously determined along with the moments or the
failure probability. Numerical results stemming from mathematical functions
indicate that the new method provides more computationally efficient design
solutions than the existing methods. Finally, stochastic shape optimization of
a jet engine bracket with 79 variables was performed, demonstrating the power
of the new method to tackle practical engineering problems.Comment: 18 pages, 2 figures, to appear in Sparse Grids and
Applications--Stuttgart 2014, Lecture Notes in Computational Science and
Engineering 109, edited by J. Garcke and D. Pfl\"{u}ger, Springer
International Publishing, 201
Recommended from our members
Design and Characterization Low-loss modes in Dielectric-Coated Hollow-core waveguides at THz Frequency
Designs of hollow-core rectangular, circular, and elliptical waveguides with inner coating of silver and polystyrene (PS) are presented for low-loss terahertz guidance. The PS thickness deposited over silver is optimized to achieve the lowest possible loss for each waveguide at the frequency of 2.5 THz. The mode also tends to be a near-Gaussian in shape, easy for coupling to transmitter and receiver. The lowest propagation loss of 0.13 dB/m is obtained for the mode in a circular waveguide with 2200 ÎĽm bore diameter by using a full-vectorial finite element method. It is also shown here that rectangular and elliptical waveguides with a similar core area offer a lower loss value for the Hp21 mode and the LP02 mode, respectively, compared to a circular waveguide. Besides this optimized rectangular waveguide not only shows a minimum loss of 0.09 dB/m but with 4 times higher loss for the other polarization, hence the polarization state of the signal can also be maintained in this waveguide
Recommended from our members
Ultra low bending loss equiangular spiral photonic crystal fibers in the terahertz regime
An Equiangular Spiral Photonic Crystal Fiber (ES-PCF) design in Topas® for use in the Terahertz regime is presented. The design shows ultra low bending loss and very low confinement loss compared to conventional Hexagonal PCF (H-PCF). The ES-PCF has excellent modal confinement properties, together with several parameters to allow the optimization of the performance over a range of important characteristics. A full vector Finite Element simulation has been used to characterize the design which can be fabricated by a range of techniques including extrusion and drilling
Implications of a Quantum Mechanical Treatment of the Universe
We attempt to treat the very early Universe according to quantum mechanics.
Identifying the scale factor of the Universe with the width of the wave packet
associated with it, we show that there cannot be an initial singularity and
that the Universe expands. Invoking the correspondence principle, we obtain the
scale factor of the Universe and demonstrate that the causality problem of the
standard model is solved.Comment: LaTex, 5 pages, 1 figure, to be published in Mod. Phys. Lett.
- …