Papers by Keyword: Interference

Abstract: One off the most powerful assembly technique is the shrink-fitting process.It is found in many fields such us mechanics, petroleum, military industries as well as in nuclear power plants etc. This article developed an analytical formulation of shrink-fitted Functionally Graded Material axisymmetric thick-walled cylinder based on the linear plane elasticity theory. The stresses and displacement fields in the thick cylindrical shells are calculated using the laws of linear elasticity. The resulting displacements and stresses are analyzed, and particularly the residual contact pressure and her relationship with the interference values. The results show that the variation of the FGM material composition has a clear effect on the fit pressure in the intersection area of the two fitted cylinders. The value of this pressure affects the distribution of radial and tangential stresses in the FGM cylinder walls. Subsequently, we highlighted the influence of the interference value, on the residual contact pressure which increases with the increase of the interference value. The stresses are modeled for a case study using MATLAB software. keywords. shrink-fit, FGM, Interference, residual stress, Elasticity.

Abstract: In present work, two types of Interferometric Fiber Optic Sensor (Fabry – Perot & Modal Sensor) have been demonstrate and investigated. The main parameter studied of this contribute is the sensitivity, the strain could be induced by make a stress on the optical fiber. The strain effect at the fiber due to variation of the intensity in the output of the optical fiber. Then, the modes of electromagnetic waves that propagate in the fiber could be analyzed to determine the sensitivity depend on fringe rates. I conclude from this study the Extrinsic Fabry – Perot Interferometry structure is more sensitive than Modal Sensor.

Abstract: The study focuses on the effect of low-frequency noise on resistance converter of teraommeters to test cable insulation. A mathematical pendulum was used to simulate low frequency electromagnetic interference. It was found that the greatest effect is exerted by dynamic effects of electrostatic charges that accumulate on the printed circuit board, electronic components, structural elements of the resistance-to-voltage converter, and on the test cable sheath. The effect of constant and alternating magnetic fields on measurement of resistance of insulating materials is insignificant.

Abstract: In this paper is considered the autocorrelator of ultrashort pulses based a Michelson interferometer, his schemes and operating principles. The method of measuring ultrashort pulses is given. The schemes and principles of operation of the main nodes of the autocorrelation receiver are presented: the optical-mechanical part (the construction of the Michelson interferometer) and the electronic part, which includes a photodetector module, a control and data processing unit with a speaker amplifier, and a personal computer.

Abstract: Many machine components work within an elastohydrodynamic lubrication (EHL) regime. Unconfined space is widely used in EHL formulas for to evaluate film thickness, which is related to operating conditions and material properties. In classical theoretical EHL studies, film pressure matches the loading balance and the location of the lubricated components can be adjusted. In the present study, the lubrication performance is analyzed based on a confined space. A thrust ball bearing lubrication simulation system is designed and used to examine the relationship between velocity and film thickness. It was found that the central film thickness and minimum film thickness increased as entrainment velocity increased. Fluctuations in the film thickness curve were observed, which may have arisen from slight gap variations in the ball-plate contact area.

Abstract: With the advancement in telecommunication in indoor environment, the use of wireless technology for information systems has drastically increased. The intensive use of indoor wireless devices in 2.4GHz and 5.8GHz ISM bands causes mutual interference in neighboring networks which degrades the system performance. Secure personal communication within such wireless networks is also another important problem. A band-stop frequency selective surface (operating in the WLAN frequency band) which is attached to the walls of buildings can provide a solution for these interference and security problems. In this work, a new band-stop hybrid frequency selective surface element consisting of two circular looped type geometries is introduced which is capable of attenuating the incoming 2.4GHz and 5.8GHz ISM signals minimum 13dB for all polarizations and incident angles varies from 0⁰ to 45⁰. Besides, a periodic cell size (p=26,5mmm) which is almost one fifth of the first resonance wavelength is obtained.

Abstract: In this study, numerical experiment of flow around the close two airfoils which arranged in parallel with attack angle was performed. The aspect of flow and the instantaneous fluid force act on symmetrical airfoil (NACA0012) with attack angle were investigated using a vortex method at the Reynolds number Re=4.05×10⁵, in ranges of the distance ratio L/c = 0.0, 0.25, 0.50 and 1.0 (here, L/c = 0.0 means single airfoil case) and the attack angle α = 0, 5, 10 and 15 degrees, (here, α =15 degree case is performed on single airfoil case only). As a result of calculations, in the case of two airfoils, the large lift was able to be obtained as compared with the single airfoil, but it was found in it that they are about 1.5 times in the case of single airfoil. And it was shown that the fluid force characteristic of each airfoil of two airfoils differs from the case of single airfoil.

Abstract: Traveling wave in transit, wave head is easy to produce distortion and affected by environmental interference, so accurately measuring the head of traveling wave singularity occurrence time become extremely difficult. The key to improve the precision of traveling wave detection is to accurately capture the happening time of wave head of singular points. Recently, traveling wave singularity detection usually use wavelet, EMD-HHT transform technique, but both have mixing phenomenon, affecting the accuracy of detection. In this paper, we propose a new method that use Duffing chaotic oscillator to suppress traveling wave interference signal. By Matlab simulation and it is proved that this method can effectively suppress noise singular point. Meanwhile, we propose an anti-mixing EEMD-HHT wave head detection technology. Through simulation experiment and field test, it is proved that, compared with EMD, EEMD can more accurately identify the traveling wave arrival time, detection accuracy increasing by 1.52%.

Abstract: For 7050-T7451 plate with the thickness of 16mm, ∅6 hi-bolts were installed with 0.11mm interference by electromagnetic riveting. Split-sleeve cold expansion was employed with 4% expansion. Combine joining of 4% expansion+0.11mm interference was carried out. The effect of strengthening was estimated from microstructure, stress and fatigue life. The results show that the microstructures are the same before and after strengthened. Along the installing direction, materials flow locate near the exit. Residual compressive stresses generate by strengthening process and gradually increase by the process of interference bolted joining, split-sleeve cold expansion and combine joining, within some diameter in the exit. The fatigue lives N₅₀ also gradually increase by the process of interference bolted joining, split-sleeve cold expansion and combine joining.

Abstract: This paper describes a preliminary study of the possibility for greenhouse interference during ammonia measurement in the 200nm-230 nm region. An absorption spectrum for ammonia was compared with the greenhouse gases absorption lines to theoretically justify that there were no discernible interference effects during the ammonia concentration measurements. It was theoretically found that the primary greenhouse gases namely ozone, methane and nitrous oxide have no significant interference for ammonia sensing in the 200nm-210 nmregion.