Abstract: A filter is used to remove undesirable frequency information from a dynamic signal. This paper shows that the Znotch filter filtering technique can be applied to remove the noise nuisance from a machining signal. In machining, the noise components were identified from the sound produced by the operation of machine components itself such as hydraulic system, motor, machine environment and etc. By correlating the noise components with the measured machining signal, the interested components of the measured machining signal which was less interfered by the noise, can be extracted. Thus, the filtered signal is more reliable to be analysed in terms of noise content compared to the unfiltered signal. Significantly, the I-kaz method i.e. comprises of three dimensional graphical representation and I-kaz coefficient, Z∞ could differentiate between the filtered and the unfiltered signal. The bigger space of scattering and the higher value of Z∞ demonstrated that the signal was highly interrupted by noise. This method can be utilised as a proactive tool in evaluating the noise content in a signal. The evaluation of noise content is very important as well as the elimination especially for machining operation fault diagnosis purpose. The Z-notch filtering technique was reliable in extracting noise component from the measured machining signal with high efficiency. Even though the measured signal was exposed to high noise disruption, the signal generated from the interaction between cutting tool and work piece still can be acquired. Therefore, the interruption of noise that could change the original signal feature and consequently can deteriorate the useful sensory information can be eliminated.
Abstract: The objective of this paper is to analyze the
performance of a double-sided axial flux permanent magnet
brushless DC (AFPM BLDC) motor with two-phase winding.
To study the motor operation, a mathematical dynamic model
has been proposed for motor, which became the basis for
simulations that were performed using MATLAB/SIMULINK
software package. The results of simulations were presented
in form of the waveforms of selected quantities and the
electromechanical characteristics performed by the motor. The
calculation results show that the two-phase motor version
develops smooth torque and reaches high efficiency. The twophase
motor can be applied where more smooth torque is
required. Finally a study on the influence of switching angle
on motor performance shows that when advance switching
technique is used, the motor operates with the highest
efficiency.
Abstract: Fabrication and efficiency enhancement of non-mercury, high efficiency and green field emission lamps using carbon nano-materials such as carbon nanotubes as cathode field emitters was studied. Phosphor was coated on the ITO glass or metal substrates as the anode. The luminescence efficiency enhancement was carried out by upgrading the uniform of the emitters, improving electron and thermal conductivity of the phosphor and the optimization of the design of different cathode/anode configurations. After evaluation of the aforementioned parameters, the luminescence efficiency of the field emission lamps was raised.
Abstract: Intelligent Video-Surveillance (IVS) systems are
being more and more popular in security applications. The analysis
and recognition of abnormal behaviours in a video sequence has
gradually drawn the attention in the field of IVS, since it allows
filtering out a large number of useless information, which guarantees
the high efficiency in the security protection, and save a lot of human
and material resources. We present in this paper ADABeV, an
intelligent video-surveillance framework for event recognition in
crowded scene to detect the abnormal human behaviour. This
framework is attended to be able to achieve real-time alarming,
reducing the lags in traditional monitoring systems. This architecture
proposal addresses four main challenges: behaviour understanding in
crowded scenes, hard lighting conditions, multiple input kinds of
sensors and contextual-based adaptability to recognize the active
context of the scene.
Abstract: Nowadays, HPC, Grid and Cloud systems are evolving
very rapidly. However, the development of infrastructure solutions
related to HPC is lagging behind. While the existing infrastructure is
sufficient for simple cases, many computational problems have more
complex requirements.Such computational experiments use different
resources simultaneously to start a large number of computational
jobs.These resources are heterogeneous. They have different
purposes, architectures, performance and used software.Users need a
convenient tool that allows to describe and to run complex
computational experiments under conditions of HPC environment.
This paper introduces a modularworkflow system called SEGL
which makes it possible to run complex computational experiments
under conditions of a real HPC organization. The system can be used
in a great number of organizations, which provide HPC power.
Significant requirements to this system are high efficiency and
interoperability with the existing HPC infrastructure of the
organization without any changes.
Abstract: The excellent suitability of the externally excited synchronous
machine (EESM) in automotive traction drive applications
is justified by its high efficiency over the whole operation range and
the high availability of materials. Usually, maximum efficiency is
obtained by modelling each single loss and minimizing the sum of all
losses. As a result, the quality of the optimization highly depends on
the precision of the model. Moreover, it requires accurate knowledge
of the saturation dependent machine inductances. Therefore, the
present contribution proposes a method to minimize the overall losses
of a salient pole EESM and its inverter in steady state operation based
on measurement data only. Since this method does not require any
manufacturer data, it is well suited for an automated measurement
data evaluation and inverter parametrization. The field oriented control
(FOC) of an EESM provides three current components resp. three
degrees of freedom (DOF). An analytic minimization of the copper
losses in the stator and the rotor (assuming constant inductances) is
performed and serves as a first approximation of how to choose the
optimal current reference values. After a numeric offline minimization
of the overall losses based on measurement data the results are
compared to a control strategy that satisfies cos (ϕ) = 1.
Abstract: In this paper the authors propose a flexible electronic solution, to improve the energetic efficiency of a thermo plant. This is achieved by replacing the mechanical gear box, placed traditionally between a gas turbine and a synchronous generator; by a power electronic converter. After reminding problematic of gear boxes and interest of a proposed electronic solution in high power plants, the authors describe a new control strategy for an indirect frequency converter, which is characterized by its high efficiency due to the use of SWM: Square Wave Modulation. The main advantage of this mode is the quasi absence of switching losses. A control method is also proposed to resolve some problems incurred by using square wave modulation, in particular to reduce the harmonics distortion of the output inverter voltage and current. Simulation examples as well as experimental results are included.
Abstract: Due to the high increase in and demand for a wide assortment of applications that require low-cost, high-efficiency, and compact systems, RF power amplifiers are considered the most critical design blocks and power consuming components in wireless communication, TV transmission, radar, and RF heating. Therefore, much research has been carried out in order to improve the performance of power amplifiers. Classes-A, B, C, D, E and F are the main techniques for realizing power amplifiers.
An implementation of high efficiency class-F power amplifier with Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) was realized in this paper. The simulation and optimization of the class-F power amplifier circuit model was undertaken using Agilent’s Advanced Design system (ADS). The circuit was designed using lumped elements.
Abstract: Sol-gel method has been used to fabricate
nanocomposite films on glass substrates composed halloysite clay
mineral and nanocrystalline TiO2. The methodology for the synthesis
involves a simple chemistry method utilized nonionic surfactant
molecule as pore directing agent along with the acetic acid-based solgel
route with the absence of water molecules. The thermal treatment
of composite films at 450oC ensures elimination of organic material
and lead to the formation of TiO2 nanoparticles onto the surface of
the halloysite nanotubes. Microscopy techniques and porosimetry
methods used in order to delineate the structural characteristics of the
materials. The nanocomposite films produced have no cracks and
active anatase crystal phase with small crystallite size were deposited
on halloysite nanotubes. The photocatalytic properties for the new
materials were examined for the decomposition of the Basic Blue 41
azo dye in solution. These, nanotechnology based composite films
show high efficiency for dye’s discoloration in spite of different
halloysite quantities and small amount of halloysite/TiO2 catalyst
immobilized onto glass substrates. Moreover, we examined the
modification of the halloysite/TiO2 films with silver particles in order
to improve the photocatalytic properties of the films. Indeed, the
presence of silver nanoparticles enhances the discoloration rate of the
Basic Blue 41 compared to the efficiencies obtained for unmodified
films.