The New Method To Calibrate Iso/cie General Skies modelled In Artificial Skies

2021 ◽  
pp. 11-20
Author(s):  
Stanislav Darula ◽  
Richard Kittler
Keyword(s):  
New Method ◽  
Electrical System ◽  
Illumination System ◽  
Sky Type ◽  
Fish Eye ◽  
Very High ◽  
Calibration Step

Recently sky luminance distributions under fifteen ISO/CIE sky types were standardised in relative terms, i.e. all elementary sky luminance are normalised by the zenith luminance in nature. However, these standard sky luminance patterns can be characterised also in their physical units, see in CIE215:20014 which can be reduced by suitable intensity scales to simulate the very high natural sky luminance in laboratory under artificial sky domes. For the design of the electric illumination system of the artificial sky the appropriate zenith luminance for each sky type has to be derived respecting the indicatrix and gradation functions of each sky type. Thus, the sky patterns simulated in the artificial sky can be calibrated either by luminance measurements or by analysing fish-eye photos taken from the sky centre showing the smoothness and gradual changes of homogeneous sky type luminance patterns. The sky luminance images can be utilised to proceed with the adjustment or dimming of the LED electrical system to the final calibration check containing zenith luminance and exterior illuminance in the second calibration step.

Review on Switches for Power Applications: Macro to Micro

2019 ◽  
Vol 12 (3) ◽  
pp. 200-209
Author(s):  
Femi Robert
Keyword(s):  
Leakage Current ◽  
Power Loss ◽  
Low Cost ◽  
Electrical System ◽  
High Isolation ◽  
Fast Switching ◽  
Environmental Friendly ◽  
State Resistance ◽  
Very High ◽  
Bulk Production

Background: Switches are important component in electrical system. The switches needs to have the advantages of low ON-state resistance, very high OFF-state resistance, high isolation, no leakage current, less power loss, fast switching, high linearity, small size, arcless and low cost in bulk production. Also these switches have to be reliable and environmental friendly. Methods: In this paper, macro and microswitches for power applications are extensively reviewed and summarized. Various types of switches such as mechanical, solid-state, hybrid and micromechanical switches have been used for power applications are reviewed. The importance and challenge in achieving arcless switching is presented. Results: The use of micromechanical switches for power applications, actuation techniques, switching modes, reliability and lifetime are also reviewed. The modeling and design challenges are also reviewed. Conclusion: The applications of micromechanical switches shows that the switches can reduce the leakage current in battery operated systems and reduce the size of the system considerably.

scholarly journals Stellar magnetic imaging from spectropolarimetric data

1996 ◽  
Vol 176 ◽  
pp. 53-60 ◽  
Author(s):  
J.-F. Donati
Keyword(s):  
Small Amplitude ◽  
High Accuracy ◽  
Spectral Lines ◽  
New Method ◽  
Doppler Imaging ◽  
Magnetic Imaging ◽  
Active Stars ◽  
Surface Fields ◽  
Very High

In this paper, I will review the capabilities of magnetic imaging (also called Zeeman-Doppler imaging) to reconstruct spot distributions of surface fields from sets of rotationnally modulated Zeeman signatures in circularly polarised spectral lines. I will then outline a new method to measure small amplitude magnetic signals (typically 0.1% for cool active stars) with very high accuracy. Finally, I will present and comment new magnetic images reconstructed from data collected in 1993 December at the Anglo-Australian Telescope (AAT).

scholarly journals Critical Dynamics of Defects and Mechanisms of Damage-Failure Transitions in Fatigue

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2554
Author(s):  
Oleg Naimark ◽  
Vladimir Oborin ◽  
Mikhail Bannikov ◽  
Dmitry Ledon
Keyword(s):  
Fatigue Damage ◽  
Kinetic Equations ◽  
Experimental Methodology ◽  
Preliminary Deformation ◽  
Scaling Properties ◽  
In Situ Data ◽  
Number Of Cycles ◽  
Fish Eye ◽  
Very High

An experimental methodology was developed for estimating a very high cycle fatigue (VHCF) life of the aluminum alloy AMG-6 subjected to preliminary deformation. The analysis of fatigue damage staging is based on the measurement of elastic modulus decrement according to “in situ” data of nonlinear dynamics of free-end specimen vibrations at the VHCF test. The correlation of fatigue damage staging and fracture surface morphology was studied to establish the scaling properties and kinetic equations for damage localization, “fish-eye” nucleation, and transition to the Paris crack kinetics. These equations, based on empirical parameters related to the structure of the material, allows us to estimate the number of cycles for the nucleation and advance of fatigue crack.

Chaotic-Sequence-Based Channel Estimation Algorithm for Secure Optical OFDM Systems

2014 ◽  
Vol 602-605 ◽  
pp. 3165-3168 ◽  
Author(s):  
Han Dong Wang ◽  
Li Qun Huang ◽  
Feng Yao
Keyword(s):  
Channel Estimation ◽  
Binary Sequence ◽  
Estimation Algorithm ◽  
Original Data ◽  
Chaotic Sequence ◽  
New Method ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Optical Ofdm ◽  
Very High

In this paper, in order to improve the security of optical OFDM system, we propose a new method to generate the pilot sequence of channel estimation using chaotic sequence. Firstly, we assign initial values to chaotic system, and calculate a chaotic sequence through an iteration method, then converting it into a binary sequence as the pilot of a DFT-based channel estimation algorithm. When the receiving end doesn’t know the chaotic-sequence-based pilot, the system will have very high BER, and can not restore the original data, which indicate that the new method provides a certain degree of security for optical OFDM systems without increasing the system complexity.

Study on Interior Fracture Property of High Strength Steel in Very High Cycle Regime

2012 ◽  
Vol 482-484 ◽  
pp. 1169-1175
Author(s):  
Ren Hao Jiang ◽  
Wei Li ◽  
Yan Ping Shi ◽  
Jiang He
Keyword(s):  
Crack Propagation ◽  
Fracture Property ◽  
Crack Nucleation ◽  
Fatigue Property ◽  
High Strength ◽  
Bearing Steel ◽  
Stable Crack Propagation ◽  
The Matrix ◽  
Fish Eye ◽  
Very High

Based on the fracture mechanics theory and fracture surface topography analysis (FRASTA) method, the interior fracture property of a bearing steel in very high cycle regime was studied by means of rotary bending fatigue test. As a result, this bearing steel represents the duplex S-N curves characteristic, where the interior inclusion-induced fracture is the predominant fracture mode in very high cycle regime. The rough granular bright facet (GBF) area corresponding to smaller inclusion is usually formed in the lifetime larger than 106 cycles, whose formation progress can be interpreted as the slow crack nucleation based on decohesion of spherical carbide from the matrix. The fatigue property in the fish-eye region outside of GBF can be interpreted as the stable crack propagation progress and that outside of fish-eye is instable crack propagation progress. The stress intensity factor ranges of GBF and fish-eye, ΔKGBF and ΔKfish-eye, can be regarded as the threshold values of controlling stable propagation and instable propagation of interior crack, respectively.

A New Method to Improve the Voltage Distribution and Electric Field Control for Conceder Bushing

2011 ◽  
Vol 110-116 ◽  
pp. 5184-5188
Author(s):  
Mahdi Hassani ◽  
Seyed Siavash Karimi Madahi ◽  
Hassan Feshki Farahani ◽  
Hossein Sarabadani
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Power Transformer ◽  
New Method ◽  
Power Transformers ◽  
Voltage Profile ◽  
Pollution Effects ◽  
Potential Surfaces ◽  
Very High ◽  
Profile Reduction

Capacitor bushings are one of the key components in power transformers. Although their price is a negligible part of the total price of the power transformer, their quality has a significant effect on performance and reliability of power transformers. In high voltage capacitor bushings, the intensity of voltage and electric field on bushing abacus is very high. This high intensity is also observed in flange parts. The amount of multi layer insulator among the electrodes or floating plates in capacitor bushing make equi-potential surfaces and reduction of electric field in these areas can greatly improve the capacitor bushing performance. In this paper, we investigate the reduction of field intensity and electrical tension and also improvement in voltage control by displacing floating plates which are in the form of aluminum foils stick to impregnated paper. To calculate the field intensity, we used the MAXWELL software using FEM (Finite element method). Using this new method of placing capacitor core its effect on voltage profile reduction and field electrical tension is shown. Over voltage and pollution effects are also investigate on power transformer bushings.

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