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Full-Text Articles in Science and Technology Studies

Novel Modulation And Control Strategy For Five-Level Anpc Converter With Unbalanced Dc Voltage Applied To A Single-Phase Grid Connected Pv System, Hamid R. Teymour, Danny Sutanto, Kashem M. Muttaqi, Phil Ciufo Apr 2015

Novel Modulation And Control Strategy For Five-Level Anpc Converter With Unbalanced Dc Voltage Applied To A Single-Phase Grid Connected Pv System, Hamid R. Teymour, Danny Sutanto, Kashem M. Muttaqi, Phil Ciufo

Dr Philip Ciufo

This paper proposes a new control strategy and a novel modulation technique for a grid-connected photo-voltaic (PV) system using a single-phase five-level flying capacitor (FC) based active-neutral-point-clamped (ANPC) converter. The proposed modulator can control the FC voltage to follow the requested reference value and simultaneously generate the required ac output voltage regardless of the values of the dc capacitor voltages of the converter. By implementing this method, smaller values of dc-link and flying capacitors can be used even in applications that could experience ripple or transient in the capacitors voltage. In the grid-connected single-phase five-level ANPC, where the capacitors can ...


Absolute Phase Recovery Of Three Fringe Patterns With Selected Spatial Frequencies, Yi Ding, Jiangtao Xi, Yanguang Yu, Fuqin Deng Jan 2015

Absolute Phase Recovery Of Three Fringe Patterns With Selected Spatial Frequencies, Yi Ding, Jiangtao Xi, Yanguang Yu, Fuqin Deng

Faculty of Engineering and Information Sciences - Papers: Part A

A new temporal approach is presented for the recovery of the absolute phase maps from their wrapped versions based on the use of fringe patterns of three different spatial frequencies. In contrast to the two-frequency method recently published, the method proposed is characterized by better anti-error capability as measured by phase error tolerance bound. A general rule for the selection of the three frequencies is presented, and its relationship to the phase error tolerance bound is derived. Theoretical analysis and experimental results are also presented to validate the effectiveness of the proposed three frequency technique.


Multiplicative Modelling Of Four-Phase Microbial Growth, María Jesús Munoz-Lopez, Maureen P. Edwards, Ulrike Schumann, Robert S. Anderssen Jan 2015

Multiplicative Modelling Of Four-Phase Microbial Growth, María Jesús Munoz-Lopez, Maureen P. Edwards, Ulrike Schumann, Robert S. Anderssen

Faculty of Engineering and Information Sciences - Papers: Part A

Microbial growth curves, recording the four-phases (lag, growth, stationary, decay) of the dynamics of the surviving microbes, are regularly used to support decision-making in a wide variety of health related activities including food safety and pharmaceutical manufacture. Often, the decision-making reduces to a simple comparison of some particular feature of the four-phases, such as the time at which the number of surviving microbes reaches a maximum. Consequently, in order to obtain accurate estimates of such features, the first step is the determination, from experimental measurements, of a quantitative characterization (model) of the four-phases of the growth-decay dynamics involved, which is ...


Using Solar Photovoltaic Thermal Collectors In Phase Change Materials Enhanced Buildings For Thermal Performance Management, Zhenjun Ma, Wenye Lin, Mohammed I. Sohel Jan 2015

Using Solar Photovoltaic Thermal Collectors In Phase Change Materials Enhanced Buildings For Thermal Performance Management, Zhenjun Ma, Wenye Lin, Mohammed I. Sohel

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents the investigation of using air-based solar photovoltaic thermal (PVT) collectors in phase change materials (PCMs) enhanced buildings for effective thermal management. PVT collectors are used to generate electricity and provide low grade heating energy to buildings for winter space heating. PCMs are either integrated into building walls to increase the local thermal mass or used as a temporary centralized thermal storage to store the low grade thermal energy derived from the PVT collectors. The thermal performance of buildings due to the integration of the PVT collectors and PCMs is tested and evaluated through computer simulations. It is ...


Novel Experimental Setup For Time-Of-Flight Mass Spectrometry Ion Detection In Collisions Of Anionic Species With Neutral Gas-Phase Molecular Targets, J C. Oller, L Ellis-Gibbings, F Ferreira Da Silva, Paulo Limao-Vieira, Gustavo Garcia Jan 2015

Novel Experimental Setup For Time-Of-Flight Mass Spectrometry Ion Detection In Collisions Of Anionic Species With Neutral Gas-Phase Molecular Targets, J C. Oller, L Ellis-Gibbings, F Ferreira Da Silva, Paulo Limao-Vieira, Gustavo Garcia

Faculty of Engineering and Information Sciences - Papers: Part A

We report a novel experimental setup for studying collision induced products resulting from the interaction of anionic beams with a neutral gas-phase molecular target. The precursor projectile was admitted into vacuum through a commercial pulsed valve, with the anionic beam produced in a hollow cathode discharge-induced plasma, and guided to the interaction region by a set of deflecting plates where it was made to interact with the target beam. Depending on the collision energy regime, negative and positive species can be formed in the collision region and ions were time-of-flight (TOF) mass-analysed. Here, we present data on O-2 precursor projectile ...


Phase Unwrapping Method Based On Multiple Fringe Patterns Without Use Of Equivalent Wavelengths, Limei Song, Yulan Chang, Jiangtao Xi, Qinghua Guo, Xin-Jun Zhu, Xiaojie Li Jan 2015

Phase Unwrapping Method Based On Multiple Fringe Patterns Without Use Of Equivalent Wavelengths, Limei Song, Yulan Chang, Jiangtao Xi, Qinghua Guo, Xin-Jun Zhu, Xiaojie Li

Faculty of Engineering and Information Sciences - Papers: Part A

In order to decrease the noise enhancement in the process of phase unwrapping, we present a new phase unwrapping approach for multiple wavelength phase shift profilometry. In this approach, a series of fringe images with only three wavelengths are captured by the 3D measurement system, and it does not need to calculate the equivalent wavelengths and the equivalent phases. As a result, the noise enhancement is avoided, leading to improved precision in the absolute phase map recovery. Experiment results demonstrate that the proposed method is more robust and effective compared to the existing TWPSP method.


Shadow Removal Method For Phase-Shifting Profilometry, Lei Lu, Jiangtao Xi, Yanguang Yu, Qinghua Guo, Yongkai Yin, Limei Song Jan 2015

Shadow Removal Method For Phase-Shifting Profilometry, Lei Lu, Jiangtao Xi, Yanguang Yu, Qinghua Guo, Yongkai Yin, Limei Song

Faculty of Engineering and Information Sciences - Papers: Part A

In a typical phase-shifting profilometry system for the three-dimensional (3D) shape measurement, shadows often exist in the captured images as the camera and projector probe the object from different directions. The shadow areas do not reflect the fringe patterns which will cause errors in the measurement results. This paper proposed a new method to remove the shadow areas from taking part in the 3D measurement. With the system calibrated and the object reconstructed, the 3D results are mapped on a point-by-point basis into the corresponding positions on the digital micro-mirror device (DMD) of the projector. A set of roles are ...


Multi-Phase Variety Trials Using Both Composite And Individual Replicate Samples: A Model-Based Design Approach, Alison B. Smith, David G. Butler, C R. Cavanagh, Brian R. Cullis Jan 2015

Multi-Phase Variety Trials Using Both Composite And Individual Replicate Samples: A Model-Based Design Approach, Alison B. Smith, David G. Butler, C R. Cavanagh, Brian R. Cullis

Faculty of Engineering and Information Sciences - Papers: Part A

The present paper provides an approach for the design and analysis of variety trials that are used to obtain quality trait data. These trials are multi-phase in nature, comprising a field phase followed by one or more laboratory phases. Typically the laboratory phases are costly relative to the field phase and this imposes a limit on the number of samples that can be tested. Historically, this has been achieved by sacrificing field replication, either by testing a single replicate plot for each variety or a single composite sample, obtained by combining material from several field replicates. An efficient statistical analysis ...


Review Of Solid-Liquid Phase Change Materials And Their Encapsulation Technologies, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis Jan 2015

Review Of Solid-Liquid Phase Change Materials And Their Encapsulation Technologies, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis

Faculty of Engineering and Information Sciences - Papers: Part A

Various types of solid-liquid phase change materials (PCMs) have been reviewed for thermal energy storage applications. The review has shown that organic solid-liquid PCMs have much more advantages and capabilities than inorganic PCMs but do possess low thermal conductivity and density as well as being flammable. Inorganic PCMs possess higher heat storage capacities and conductivities, cheaper and readily available as well as being non-flammable, but do experience supercooling and phase segregation problems during phase change process. The review has also shown that eutectic PCMs have unique advantage since their melting points can be adjusted. In addition, they have relatively high ...


Modeling Minimum Transport Boundary For Fluidized Dense-Phase Pneumatic Conveying Systems, G Setia, Soumya Suddha Mallick, Renhu Pan, Peter W. Wypych Jan 2015

Modeling Minimum Transport Boundary For Fluidized Dense-Phase Pneumatic Conveying Systems, G Setia, Soumya Suddha Mallick, Renhu Pan, Peter W. Wypych

Faculty of Engineering and Information Sciences - Papers: Part A

For the reliable design of fluidized dense-phase pneumatic conveying systems, it is of paramount importance to accurately estimate blockage conditions or the minimum transport boundary. Existing empirical models for the fluidized dense-phase conveying of fine powders are either based on a limited number of products and pipelines or have not been tested for their accuracy and stability over a wide range of scale-up conditions. In this paper, based on the test results of 22 different powders conveyed through 38 pipelines, a unified model for the minimum transport boundary has been developed that represents gas Froude number as a function of ...


An In-Situ Neutron Diffraction Study Of A Multi-Phase Transformation And Twinning-Induced Plasticity Steel During Cyclic Loading, Ahmed A. Saleh, Donald W. Brown, Elena V. Pereloma, Bjorn Clausen, Christopher H. J Davies, Carlos N. Tome, Azdiar A. Gazder Jan 2015

An In-Situ Neutron Diffraction Study Of A Multi-Phase Transformation And Twinning-Induced Plasticity Steel During Cyclic Loading, Ahmed A. Saleh, Donald W. Brown, Elena V. Pereloma, Bjorn Clausen, Christopher H. J Davies, Carlos N. Tome, Azdiar A. Gazder

Faculty of Engineering and Information Sciences - Papers: Part A

In-situ neutron diffraction during cyclic tension-compression loading (þ3.5% to 2.8%) of a 17Mn-3Al-2Si-1Ni-0.06C steel that exhibits concurrent transformation and twinning -induced plasticity effects indicated a significant contribution of intragranular back stresses to the observed Bauschinger effect. Rietveld analysis revealed a higher rate of martensitic transformation during tension compared to compression. Throughout cycling, a0-martensite exhibited the highest phase strains such that it bears an increasing portion of the macroscopic load as its weight fraction evolves. On the other hand, the e-martensite strain remained compressive as it accommodated most of the internal strains caused by the shape misfit associated ...


Improving Fault Ride-Through Of Three Phase Voltage Source Inverter During Symmetrical Fault Using Dc Link Fault Current Limiter, Mehrdad Tarafdar Hagh, Amin Jalilian, Seyed Behzad Naderi, Michael Negnevitsky, Kashem M. Muttaqi Jan 2015

Improving Fault Ride-Through Of Three Phase Voltage Source Inverter During Symmetrical Fault Using Dc Link Fault Current Limiter, Mehrdad Tarafdar Hagh, Amin Jalilian, Seyed Behzad Naderi, Michael Negnevitsky, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

The majority of distributed generation (DG) units utilize three phase voltage source inverter (VSI) to exchange electric power with the utility grid. The VSI employs semiconductor devices (SDs) with limited current withstand capabilities which are very vulnerable during grid faults. However, to ensure a secure and reliable operation of power systems at high penetration level of the DGs, most of the new grid codes worldwide require that the VSIs must have fault ride-Through (FRT) capability. This paper presents a DC link fault current limiter (DLFCL) based VSI FRT scheme to improve its FRT capability. In the proposed scheme, the DLFCL ...