A study of electric field behind isolated metal plate in a radiated immunity test set up

2017 ◽  
Vol 6 (2) ◽  
pp. 69-72
Author(s):  
David A. Weston
Keyword(s):  
Test Set ◽  
Author(s):  
Y K Ahn ◽  
J-Y Ha ◽  
Y-H Kim ◽  
B-S Yang ◽  
M Ahmadian ◽  
...  

This paper presents an analytical and experimental analysis of the characteristics of a squeeze-type magnetorheological (MR) mount which can be used for various vibration isolation areas. The concept of the squeeze-type mount and details of the design of a squeeze-type MR mount are discussed. These are followed by a detailed description of the test set-up for evaluating the dynamic behaviour of the mount. A series of tests was conducted on the prototype mount built for this study, in order to characterize the changes occurring as a result of changing electrical current to the mount. The results of this study show that increasing electrical current to the mount, which increases the yield stress of the MR fluid, will result in an increase in both stiffness and damping of the mount. The results also show that the mount hysteresis increases with increase in current to the MR fluid, causing changes in stiffness and damping at different input frequencies.


Author(s):  
Paul Bertier ◽  
Brianna Heazlewood

Abstract External fields have been widely adopted to control and manipulate the properties of gas-phase molecular species. In particular, electric fields have been shown to focus, filter and decelerate beams of polar molecules. While there are several well-established approaches for controlling the velocity and quantum-state distribution of reactant molecules, very few of these methods have examined the orientation of molecules in the resulting beam. Here we show that a buffer gas cell and three-bend electrostatic guide (coupled to a time-of-flight set-up) can be configured such that 70% of ammonia molecules in the cold molecular beam are oriented to an external electric field at the point of detection. With a minor alteration to the set-up, an approximately statistical distribution of molecular orientation is seen. These observations are explained by simulations of the electric field in the vicinity of the mesh separating the quadrupole guide and the repeller plate. The combined experimental apparatus therefore offers control over three key properties of a molecular beam: the rotational state distribution, the beam velocity, and the molecular orientation. Exerting this level of control over the properties of a molecular beam opens up exciting prospects for our ability to understand what role each parameter plays in reaction studies.


The distortion of the lines of flow of an electric current in a thin metal plate by the action of a magnetic field was discovered in 1879. Hall attributed this to the action of the magnetic field on the molecular currents in the metal film, which were deflected to one side or the other and accompanied by a corresponding twist of the equipotential lines. This explanation did not pass without criticism, and another theory of the effect found by Hall was published in 1884. In that paper the author seeks to explain the effect by assuming a combination of certain mechanical strains and Peltier effects, a thermo-electric current being set up between the strained and the unstrained portions. The effect of such strain was to produce a reverse effect in some metals, and these were precisely the metals for which the Hall effect was found to reverse. Aluminium was the only exception. In other respects, however, as shown by Hall in a later paper, Bidwell's theory did not stand the test of experiment, and the results lend no support to his theory, while they are in complete accordance withe the explanation that the molecular currents are disturbed by the action of the magnetic field. On the electron theory of metallic conduction, the mechanism of the Hall effect is more obvious, but at present no satisfactory explanation of the reversal found in some metals is known. Further experiments have made it clear that there is a real deflection of the elementary currents, due to the application of the magnetic field, independent of any effect due to strain.


Holzforschung ◽  
2015 ◽  
Vol 69 (4) ◽  
pp. 457-462 ◽  
Author(s):  
Eva Höllbacher ◽  
Cornelia Rieder-Gradinger ◽  
Daniel Strateva ◽  
Ewald Srebotnik

Abstract A large-scale test set-up was designed to evaluate the volatile organic compound (VOC) emissions of building materials in a real room situation but under laboratory conditions. Two model rooms (ModR) with a volume of 30 m3 each were constructed of the wood-based building materials X-lam and OSB, respectively. Temperature and relative humidity (RH) inside the ModR were kept in a range of 21°C–25°C and 45%–55% RH. VOCs were collected at 13 different times over a period of 23 weeks, and the total VOC (TVOC) concentration was calculated from GC/MS data. Results were quantified as toluene equivalents (TE). In the X-lam-ModR, the TVOC concentration decreased by 64% over the whole measurement period from 115 to 41 μg m-3 TE. Terpenes were the most abundant substance group and accounted, on average, for 80% of the TVOC concentration. In the OSB-ModR, the TVOC concentration decreased by 72% from 443 to 124 μg m-3 TE. Aldehydes showed the highest concentrations, accounting, on average, for 52% of the TVOC, while 38% were terpenes. The results show that this type of test provides realistic data for the praxis.


2013 ◽  
Vol 712-715 ◽  
pp. 1235-1240
Author(s):  
Pei Wu ◽  
Yong An Zhang ◽  
Chuan Zhong Xuan ◽  
Yan Hua Ma

The dynamic mechanical responses of resistance welding machine,which is mainly governed by the mechanical parameters of the machine, is very important to the weld quality especially in projection welding when collapse or deformation of work piece occurs. In this paper, a mathematical model for characterizing the dynamic mechanical response of resistance welding machine and a special test set-up called breaking test set-up have been developed. Based on the model and the test results, the mechanical parameters of the machine were identified, including the equivalent mass, the damping coefficient, and the stiffness for both electrode systems.


Author(s):  
Johan Anderson ◽  
Lars Boström ◽  
Robert Jansson ◽  
Bojan Milovanović

Presented is a comparison between full-scale façade tests where SP Fire 105 and BS 8414-1 were used regarding repeatability and the use of modelling to discern changes in the set-ups. Results show that the air movements around the test set-up (the wind) may have a significant impact on the tests and that the heat exposure to the façade surface will among other depend on the thickness of the test specimen. Also demonstrated was that good results could be obtained by modelling of the façade fire tests giving us the opportunity to use these methods to determine the effect of a change in the experimental setup.


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