Search results for "Axia"
showing 10 items of 638 documents
Closed-loop bandwidth impact on MVSA for rotor broken bar diagnosis in IRFOC double squirrel cage induction motor drives
2013
This paper investigates the detectability of rotor broken bars in indirect rotor flux oriented control (IRFOC) for variable speed double cage induction motor drives, using vibration signature analysis techniques. The Impact of the closed loop control system cannot be neglected when the detection of rotor asymmetries in the machine is based on the signature analysis of electrical or mechanical variables. Therefore, the investigation of rotor fault components for different bandwidths of closed-loop regulators is necessary to evaluate its relevance in the above listed variables. This paper investigates the impact of the control system on relevance of the fault components computed from axial an…
Comparison of the Rain Flow Algorithm and the Spectral Method for Fatigue Life Determination Under Uniaxial and Multiaxial Random Loading
2008
This paper presents the strain energy density parameter used for fatigue life calculation under random loading by two methods. The first method is based on schematization of energy parameter histories with the rain flow algorithm. The other one is based on moments of the power spectral density function of the energy parameter. The experimental data of fatigue tests of 10HNAP steel under constant amplitude and random uniaxial loading with non-gaussion probability distribution, zero mean value, and wide-band frequency spectrum used for comparison of the rain flow algorithm and the spectral method gave satisfactory results. Next, histories of the random stress tensor with normal probability di…
Concrete columns confined with fibre reinforced cementitious mortars: Experimentation and modelling
2014
Abstract The structural behaviour of concrete columns strengthened with a system made up of fibre nets embedded in an inorganic stabilized cementitious matrix under an uniaxial load was investigated. Medium size specimens with circular and square cross-section were cast and subjected to monotonic uniaxial compression, to investigate the efficiency of a p-Phenylene BenzobisOxazole (PBO) Fibre Reinforced Cementitious Mortar (FRCM) system in increasing both strength and ductility. The experimental results show that the confinement system adopted produced a noticeable increment in strength and ductility, though the low mechanical ratios of fibre considered were not always able to ensure hardeni…
R.C. columns strengthened by PBO-FRCM under axial force and bending moment
2017
Fabric-Reinforced Cementitious Matrix (FRCM) systems, also known as Textile Reinforced Concrete (TRC) are nowadays widely used as confining material to enhance both strength and deformation capacity of columns of seismic resistant r.c. frames. In the past, when carbon fiber was used in the textile, experimental results showed that the efficiency of the wrapping is limited by the connection between substrate and fiber, which is not as effective as when epoxy resins are used. To improve the strength of the connection between fibres and mortar binder in FRCM system, the use of p-Phenylene BenzobisOxazole (PBO), having a molecular structure capable of establishing chemical bonds with hydrated c…
Dynamic Behaviour of an Axially Moving Plate Undergoing Small Cylindrical Deformation Submerged in Axially Flowing Ideal Fluid
2011
Abstract The out-of-plane dynamic response of a moving plate, travelling between two rollers at a constant velocity, is studied, taking into account the mutual interaction between the vibrating plate and the surrounding, axially flowing ideal fluid. Transverse displacement of the plate (assumed cylindrical) is described by an integro-differential equation that includes a local inertia term, Coriolis and centrifugal forces, the aerodynamic reaction of the external medium, the vertical projection of membrane tension, the bending resistance, and external perturbation forces. In the two-dimensional model thus set up, the aerodynamic reaction is found analytically as a functional of the cylindri…
Continuous-Flow Synthesis of Ni(0) Nanoparticles Using a Cone Channel Nozzle or a Micro Coaxial-Injection Mixer
2015
To synthesize nickel(0) nanoparticles by wet chemical reduction using hydrazine with an average size distribution below 100 nm, two different reactor concepts were developed. With a cone channel nozzle, the reactant solutions were sprayed into a batch for further processing and reduction at elevated temperatures. Another concept uses a micro-coaxial injection mixer connected to a heated tube to establish a fully continuously operating reactor. To shorten the time for reduction of the nickel, salt temperatures up to 180 °C are applied. To avoid uncontrolled residence time, the whole system was pressurized up to 80 bar. Approximately 80 L reactant solution, i.e., 1 kg nickel(0) nanoparticles,…
Active mixing inside double emulsion segments in continuous flow
2015
Fast mixing is essential for many microfluidic applications, especially for flow at low Reynolds numbers. A capillary tube-in-tube coaxial flow setup in combination with a glass microreactor was used to produce immiscible multiphase segments. These double emulsion segments are composed of an organic solvent as the shell (outer) phase and a completely fluorinated liquid (Fluorinert® FC-40) as the core (inner) phase. Due to the higher density of the core droplets, they are responsive to changing their position to the force of gravity (g-force). By gently shaking or jiggling the reactor, the core drop flows very fast in the direction of the g-field without leaving the shell organic phase segme…
Permanent magnet bottom-stirred swirling flow in coaxial shallow cylindrical containers
2021
Here, an original rotating permanent magnet (RPM) system placed coaxially with the liquid metal container is studied as an effective means of generating flow in shallow cylinders for potential application in aluminum metallurgy (e.g., for ladle stirring and metal dosing). The studied RPM system generates volume force with strong axial variation and force maximum near the radial midpoint. The numerical and experimental data show that, in the shallow cylinder case, the azimuthal velocity follows the force radial distribution. The resulting velocity maximum occurs near the radial midpoint, unlike in the traditional rotating magnetic field (RMF) stirrer systems, where the velocity maximum occur…
CFD prediction of shell-side flow and mass transfer in regular fiber arrays
2021
Numerical simulations were conducted for fully developed, steady-state flow with mass transfer in fiber bundles arranged in regular lattices. The porosity was 0.5 and the Schmidt number 500. Several combinations of axial flow, transverse flow and flow attack angles in the cross-section plane were considered. The axial and transverse Reynolds numbers Rez , ReT were made to vary from 10(^−4) to 10(^2). Concentration boundary conditions, and the definition of an average Sherwood number, were addressed. Results for the hydraulic permeability were compared with the literature. Both hexagonal and square lattices were found to be hydraulically almost isotropic up to transverse flow Reynolds number…
Volumetric multiple optical traps produced by Devil's lenses
2010
We propose the use of a new diffractive optical element coined Devil's Vortex-Lens (DVL) to produce optical tweezers. In its more general form it results as the combination of a Devil’s lens and a helical vortex phase mask. It is shown that under monochromatic illumination a DVL generates a focal volume with several concatenated doughnut modes that are axially distributed according to the self-similarity of the lens. The orbital angular momentum associated to each link in the chain is investigated.