Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 31

Full-Text Articles in Engineering

Enhancing The Visibility Of Vernier Effect In A Tri-Microfiber Coupler Fiber Loop Interferometer For Ultrasensitive Refractive Index And Temperature Sensing, Fangfang Wei, Dejun Liu, Zhe Wang, Zhuochen Wang, Gerald Farrell, Qiang Wu, Gang-Ding Peng, Yuliya Semenova Nov 2020

Enhancing The Visibility Of Vernier Effect In A Tri-Microfiber Coupler Fiber Loop Interferometer For Ultrasensitive Refractive Index And Temperature Sensing, Fangfang Wei, Dejun Liu, Zhe Wang, Zhuochen Wang, Gerald Farrell, Qiang Wu, Gang-Ding Peng, Yuliya Semenova

Articles

In this paper a Vernier effect based sensor is analyzed and demonstrated experimentally in a tri-microfiber coupler (Tri-MFC) and polarization-maintaining fiber (PMF) loop interferometer (Tri-MFC-PMF) to provide ultrasensitive refractive index and temperature sensing. The main novelty of this work is an analysis of parameters of the proposed Tri-MFC-PMF with the objective of determining the conditions leading to a strong Vernier effect. It has been identified by simulation that the Vernier effect is a primary factor in the design of Tri-MFC-PMF loop sensing structure for sensitivity enhancement. It is furthermore demonstrated experimentally that enhancing the visibility of the Vernier spectrum in …


Cleanpage: Fast And Clean Document And Whiteboard Capture, Jane Courtney Oct 2020

Cleanpage: Fast And Clean Document And Whiteboard Capture, Jane Courtney

Articles

The move from paper to online is not only necessary for remote working, it is also significantly more sustainable. This trend has seen a rising need for the high-quality digitization of content from pages and whiteboards to sharable online material. However, capturing this information is not always easy nor are the results always satisfactory. Available scanning apps vary in their usability and do not always produce clean results, retaining surface imperfections from the page or whiteboard in their output images. CleanPage, a novel smartphone-based document and whiteboard scanning system, is presented. CleanPage requires one button-tap to capture, identify, crop, and …


New Robust Lpc-Based Method For Time-Resolved Morphology Of High-Noise Multiple Frequency Signals, Jin Xu, Mark Davis, Ruairí De Fréin Aug 2020

New Robust Lpc-Based Method For Time-Resolved Morphology Of High-Noise Multiple Frequency Signals, Jin Xu, Mark Davis, Ruairí De Fréin

Articles

This paper introduces a new time-resolved spectral analysis method based on the Linear Prediction Coding (LPC) method that is particularly suited to the study of the dynamics of low Signal-to-noise Ratio (SNR) signals comprising multiple frequency components. One of the challenges of the time-resolved spectral method is that they are limited by the Heisenberg-Gabor uncertainty principle. Consequently, there is a trade-off between the temporal and spectral resolution. Most of the previous studies are time-averaged methods. The proposed method is a parameterisation method which can directly extract the dominant formants. The method is based on a z-plane analysis of the poles …


Rapid Restoration Techniques For Software-Defined Networks, Ali Malik, Ruairí De Fréin, Benjamin Aziz May 2020

Rapid Restoration Techniques For Software-Defined Networks, Ali Malik, Ruairí De Fréin, Benjamin Aziz

Articles

There is increasing demand in modern day business applications for communication networks to be robust and reliable due to the complexity and critical nature of such applications. As such, data delivery is expected to be reliable and secure even in the harshest of environments. Software-Defined Networking (SDN) is gaining traction as a promising approach for designing network architectures which are robust and flexible. One reason for this is that separating the data plane from the control plane, increases the controller’s ability to configure the network rapidly. When network failure events occur, the network manager may trade-off the optimality of the …


Coordinate Transformation-Free Observer-Based Adaptive Estimation Of Distorted Single-Phase Grid Voltage Signal, Hafiz Ahmed, Mominul Ahsan, Mohamed Benbouzid, Alhussein Albarbar, Mohammad Shahjalal, Samet Biricik Jan 2020

Coordinate Transformation-Free Observer-Based Adaptive Estimation Of Distorted Single-Phase Grid Voltage Signal, Hafiz Ahmed, Mominul Ahsan, Mohamed Benbouzid, Alhussein Albarbar, Mohammad Shahjalal, Samet Biricik

Articles

This paper studies the phase and frequency estimation problem of single-phase grid voltagesignal in the presence of DC offset and harmonics. For this purpose, a novel parameterized linear modelof the grid voltage signal is considered where the unknown frequency of the grid is considered as theparameter. Based on the developed model, a linear observer (Luenberger type) is proposed. Then usingLyapunov stability theory, an estimator of the unknown grid frequency is developed. In order to deal with thegrid harmonics, multiple parallel observers are then proposed. The proposed technique is inspired by otherLuenberger observers already proposed in the literature. Those techniques use …


The Missing Parameter In Renewable Energy Power Quality Analysis, I.E. The Coefficient Of Variation: Case Study Of A 3-Mw On-Site Wind Turbine Project In Ireland, Tony Kealy Jan 2020

The Missing Parameter In Renewable Energy Power Quality Analysis, I.E. The Coefficient Of Variation: Case Study Of A 3-Mw On-Site Wind Turbine Project In Ireland, Tony Kealy

Articles

Businesses are employing distributed generation techniques, such as wind turbines, to decarbonise their electrical energy supply by reducing their dependence on fossil-fuel-generated energy. This study investigates the effectiveness of a company making a €3,500,000 investment in a 3-MW on-site wind turbine to supply some or all of their factory electrical loads. The results should benefit the investing company and other potential investors by evaluating the economic, environmental, and social outcomes of the investment. A case study methodology was used. The study found that the payback period was six and a half years, and the turbine installation benefited the environment by …


Performance Investigation Of Peak Shrinking And Interpolating The Papr Reduction Technique For Lte-Advance And 5g Signals, Somayeh Mohammady, Ronan Farrell, David Malone, John Dooley Jan 2020

Performance Investigation Of Peak Shrinking And Interpolating The Papr Reduction Technique For Lte-Advance And 5g Signals, Somayeh Mohammady, Ronan Farrell, David Malone, John Dooley

Articles

Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform generation in wideband digital communication since its first appearance in digital audio broadcasting (DAB) in Europe in 1980s, and it is indeed in use. As has been seen, the OFDM based waveforms work well with time division duplex operation in new radio (NR) systems in 5G systems, supporting delay-sensitive applications, high spectral efficiency, massive multiple input multiple output (MIMO) compatibility, and ever-larger bandwidth signals, which has demonstrated successful commercial implementation for 5G downlinks and uplinks up to 256-QAM modulation schemes. However, the OFDM waveforms suffer from high peak …


Simultaneous Measurement Of Displacement And Temperature Based On Two Cascaded Balloon-Like Bent Fibre Structures, Ke Tian, Ruoning Wang, Meng Zhang, Xiafan Wang, Xin Wang, Guoyong Jin, Elfed Lewis, Gerald Farrell, Pengfei Wang Jan 2020

Simultaneous Measurement Of Displacement And Temperature Based On Two Cascaded Balloon-Like Bent Fibre Structures, Ke Tian, Ruoning Wang, Meng Zhang, Xiafan Wang, Xin Wang, Guoyong Jin, Elfed Lewis, Gerald Farrell, Pengfei Wang

Articles

A low-cost optical fibre sensor based on two cascaded balloon-like bent fibre (BBF) structures for simultaneous displacement and temperature measurement is reported. The sensor is fabricated by cascading two balloon-like bent single-mode fibres (SMFs) which with different bending radii, generating two separate interference dips within a limited wavelength range. The wavelength of the two interference dips exhibits different responses to external displacement and temperature variations, hence simultaneous measurement of displacement and temperature is realized. Experimental results show that the proposed optical fibre sensor achieves a displacement sensitivity of −318.8 pm/μm and a temperature sensitivity of 47.4 pm/°C. Taking advantage of …


Microfluidic Flow Direction And Rate Vector Sensor Based On A Partially Gold-Coated Tfbg, Changyu Shen, Dejun Liu, Xiaokang Lian, Tingting Lang, Chunliu Zhao, Yuliya Semenova, Jacques Albert Jan 2020

Microfluidic Flow Direction And Rate Vector Sensor Based On A Partially Gold-Coated Tfbg, Changyu Shen, Dejun Liu, Xiaokang Lian, Tingting Lang, Chunliu Zhao, Yuliya Semenova, Jacques Albert

Articles

In microfluidic chips applications, the monitoring of the rate and the direction of a microfluidic flow is very important. Here, we demonstrate a liquid flow rate and a direction sensor using a partially gold-coated tilted fiber Bragg grating (TFBG) as the sensing element. Wavelength shifts and amplitude changes of the TFBG transmission resonances in the near infrared reveal the direction of the liquid flowing along the fiber axis in the vicinity of the TFBG due to a nanoscale gold layer over part of the TFBG. For a device length of 10 mm (and a diameter of 125 µm for easy …


Nis2 As A Broadband Saturable Absorber For Ultrafast Pulse Lasers, Pengfei Wang, Han Zhang, Yu Yin, Qiuyun Ouyang, Yujin Chen, Elfed Lewis, Gerald Farrell, Masaki Tokurakawa, Sulaiman Wadi Harun, Cong Wang, Shi Li Jan 2020

Nis2 As A Broadband Saturable Absorber For Ultrafast Pulse Lasers, Pengfei Wang, Han Zhang, Yu Yin, Qiuyun Ouyang, Yujin Chen, Elfed Lewis, Gerald Farrell, Masaki Tokurakawa, Sulaiman Wadi Harun, Cong Wang, Shi Li

Articles

Nickel disulfide (NiS2) has recently been found to possess strong nonlinear saturable absorption properties. This feature is highly attractive for nonlinear photonics applications. Ultrafast pulse generation is successfully demonstrated in this article for both Ytterbium- and Erbium-doped fibre lasers using micro-fibre deposited nickel disulfide (NiS2) as a saturable absorber (SA). The fabricated SA device has a modulation depth of 23% at 1.06 μm and 30.8% at 1.55 μm. Stable dissipative soliton operation was achieved at 1064.5 nm with a pulse duration of 11.7 ps and another stable conventional soliton pulse train was also obtained at 1560.2 nm with a pulse …


Negative Curvature Hollow Core Fiber Based All-Fiber Interferometer And Its Sensing Applications To Temperature And Strain, Dejun Liu, Wei Li, Qiang Wu, Haoyu Zhao, Fengzi Ling, Ke Tian, Changyu Shen, Fangfang Wei, Wei Han, Gerald Farrell, Yuliya Semenova, Pengfei Wang Jan 2020

Negative Curvature Hollow Core Fiber Based All-Fiber Interferometer And Its Sensing Applications To Temperature And Strain, Dejun Liu, Wei Li, Qiang Wu, Haoyu Zhao, Fengzi Ling, Ke Tian, Changyu Shen, Fangfang Wei, Wei Han, Gerald Farrell, Yuliya Semenova, Pengfei Wang

Articles

Negative curvature hollow core fiber (NCHCF) is a promising candidate for sensing applications; however, research on NCHCF based fiber sensors starts only in the recent two years. In this work, an all-fiber interferometer based on an NCHCF structure is proposed for the first time. The interferometer was fabricated by simple fusion splicing of a short section of an NCHCF between two singlemode fibers (SMFs). Both simulation and experimental results show that multiple modes and modal interferences are excited within the NCHCF structure. Periodic transmission dips with high spectral extinction ratio (up to 30 dB) and wide free spectral range (FSR) …


Intense Mid-Infrared Emission At 3.9 Μm In Ho3+-Doped Zbya Glasses For Potential Use As A Fiber Laser, Haiyan Zhao, Ruicong Wang, Xin Wang, Shijie Jia, Yaxian Fan, Elfed Lewis, Gerald Farrell, Shunbin Wang, Pengfei Wang Jan 2020

Intense Mid-Infrared Emission At 3.9 Μm In Ho3+-Doped Zbya Glasses For Potential Use As A Fiber Laser, Haiyan Zhao, Ruicong Wang, Xin Wang, Shijie Jia, Yaxian Fan, Elfed Lewis, Gerald Farrell, Shunbin Wang, Pengfei Wang

Articles

Intense mid-infrared emission at 3.9 µm in Ho3+-doped ZBYA glasses with direct upper laser level (Ho3+ : 5 I5) pumping at a wavelength of 888 nm is reported for the first time, to the best of our knowledge. Spectroscopic parameters were determined using the Judd–Ofelt theory and the measured absorption spectrum. The maximum emission cross section of the Ho3+-doped ZBYA glass is estimated to be 2.7 × 10−21 cm2 at 3906 nm. Additionally, fluorescence spectra and lifetimes of ZBYA glasses with different Ho3+ ion doping concentrations were measured. The results provide theoretical and experimental basis for better selection of rare-earth-doped …


Calibration To Mitigate Near-Field Antennas Effects For A Mimo Radar Imaging System, Ha Hoang, Matthias John, Patrick Mcevoy, Max Ammann Jan 2020

Calibration To Mitigate Near-Field Antennas Effects For A Mimo Radar Imaging System, Ha Hoang, Matthias John, Patrick Mcevoy, Max Ammann

Articles

A calibration method for a high-resolution hybrid MIMO turntable radar imaging system is presented. A line of small metal spheres is employed as a test pattern in the calibration process to measure the position shift caused by undesired antenna effects. The unwanted effects in the antenna near-field responses are analysed, modelled and significantly mitigated based on the symmetry and differences in the responses of the MIMO configuration.


Indirect Sliding Mode Control For Dc-Dc Sepic Converters, Hasan Komurcugil, Samet Biricik, Naki Guler Jan 2020

Indirect Sliding Mode Control For Dc-Dc Sepic Converters, Hasan Komurcugil, Samet Biricik, Naki Guler

Articles

This article presents an indirect sliding mode control (SMC) for single-ended primary-inductor converters (SEPIC). Unlike the conventional SMC methods, the proposed SMC method employs a sliding surface function based on the input current error only. The use of such sliding surface function not only simplifies the implementation but also reduces the cost of implementation. It is shown that the output voltage control can be achieved indirectly. The input current reference is generated by a proportional-integral (PI) regulator. The existence condition and the region of the closed-loop system are determined for all possibilities of the PI gains. The performance of the …


Carbon-Based Interlayers In Perovskite Solar Cells, Aleksandr P. Litvin, Xiaoyu Zhang, Kevin Berwick, Anatoly V. Fedorov, Weitao Zheng, Alexander V. Baranov Jan 2020

Carbon-Based Interlayers In Perovskite Solar Cells, Aleksandr P. Litvin, Xiaoyu Zhang, Kevin Berwick, Anatoly V. Fedorov, Weitao Zheng, Alexander V. Baranov

Articles

Perovskites are solution-processed, high-performance semiconductors of interest in low-cost photovoltaics. The interfaces between the perovskite photoactive layers and the top and bottom contacts are crucial for efficient charge transport and minimizing trapping. Control of the collection of charge carriers at these interfaces is decisive to device performance. Here, we review recent progress in the realization of efficient perovskite solar cells using cheap, easily processed, stable, carbon-based interlayers. Interface materials including graphene, carbon nanotubes, fullerenes, graphene quantum dots and carbon dots are introduced and their influence on device performance is discussed.


Accounting For The Local Field When Determining The Dielectric Loss Spectra Of Metals In The Region Of The Frequencies Of Volume, Surface And Localized Plasmon Oscillations, Tatiana Perova, Igor Shaganove, Kevin Berwick Jan 2020

Accounting For The Local Field When Determining The Dielectric Loss Spectra Of Metals In The Region Of The Frequencies Of Volume, Surface And Localized Plasmon Oscillations, Tatiana Perova, Igor Shaganove, Kevin Berwick

Articles

The optical constant of bulk metal is used to determine the dispersion of the local field under one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) confinement. 3D confinement, expressed as ε mic 2 (ω3D), corresponds to the dielectric loss spectra of spherical particles with a diameter, d, much less than the wavelength of the beam used to measure the spectrum (d << λ). Excellent agreement with the results of Mie theory and experimental data for solid colloids within alkali halide crystals was observed. The function expressed as ε mic 2 (ω1D) allows the measurement of spectral micro-characteristics in the frequency range of the longitudinal collective motion of the free electrons. This corresponds to the spectrum of dielectric losses of bulk plasma oscillations. The function ε mic 2 (ω2D) describes the spectra of the dielectric losses of surface plasma oscillations in thin metal films. It is shown that the peak positions of ε mic 2 (ω3D), ε mic 2 (ω2D) and ε mic 2 (ω1D) spectra for simple metals, viz. alkali metals as well as Al, Be, Mg, Ga, In, Sn and Si, are in agreement with experimental results from electron-energy-loss spectroscopy and various optical techniques.


Self-Similar Pcosecond Pulse Compression For Supercontinuum Generation At Mid-Infrared Wavelength In Silicon Strip Waveguides, Yujun Cheng, Jinhui Yuan, Chao Mei, Feng Li, Zhe Kang, Binbin Yan, Xian Zhou, Qiang Wu, Kuiru Wang, Xinzhu Sang, Keping Long, Chongxiu Yu, Gerald Farrell Jan 2020

Self-Similar Pcosecond Pulse Compression For Supercontinuum Generation At Mid-Infrared Wavelength In Silicon Strip Waveguides, Yujun Cheng, Jinhui Yuan, Chao Mei, Feng Li, Zhe Kang, Binbin Yan, Xian Zhou, Qiang Wu, Kuiru Wang, Xinzhu Sang, Keping Long, Chongxiu Yu, Gerald Farrell

Articles

Self-similar pulse compression has important application in highly coherent supercontinuum (SC) generation. In this paper, we numerically present the mid-infrared self-similar picosecond pulse compression in a tapered suspended silicon strip waveguide, which is designed with exponentially decreasing dispersion profile along the direction of propagation. When the variation of the Kerr nonlinear coefficient ��(z), linear and nonlinear losses, higher-order nonlinearity, and higher-order dispersion are taken into consideration, the simulation result shows that a 1 ps input pulse centered at wavelength 2.8 μm could be self-similarly compressed to 47.06 fs in a 3.9-cm waveguide taper, along with a compression factor ��c of …


On The Chirp Function, The Chirplet Transform And The Optimal Communication Of Information, Jonathan Blackledge Jan 2020

On The Chirp Function, The Chirplet Transform And The Optimal Communication Of Information, Jonathan Blackledge

Articles

—The purpose of this extended paper is to provide a review of the chirp function and the chirplet transform and to investigate the application of chirplet modulation for digital communications, in particular, the transmission of binary strings. The significance of the chirp function in the solution to a range of fundamental problems in physics is revisited to provide a background to the case and to present the context in which the chirp function plays a central role, the material presented being designed to show a variety of problems with solutions and applications that are characterized by a chirp function in …


Applications Of Artificial Intelligence To Cryptography, Jonathan Blackledge, Napo Mosola Jan 2020

Applications Of Artificial Intelligence To Cryptography, Jonathan Blackledge, Napo Mosola

Articles

This paper considers some recent advances in the field of Cryptography using Artificial Intelligence (AI). It specifically considers the applications of Machine Learning (ML) and Evolutionary Computing (EC) to analyze and encrypt data. A short overview is given on Artificial Neural Networks (ANNs) and the principles of Deep Learning using Deep ANNs. In this context, the paper considers: (i) the implementation of EC and ANNs for generating unique and unclonable ciphers; (ii) ML strategies for detecting the genuine randomness (or otherwise) of finite binary strings for applications in Cryptanalysis. The aim of the paper is to provide an overview on …


Reformulating The Binary Masking Approach Ofadress As Soft Masking, Ruairí De Fréin Jan 2020

Reformulating The Binary Masking Approach Ofadress As Soft Masking, Ruairí De Fréin

Articles

Binary masking forms the basis for a number of source separation approaches that havebeen successfully applied to the problem of de-mixing music sources from a stereo recording.A well-known problem with binary masking is that, when music sources overlap in the time-frequencydomain, only one of the overlapping sources can be assigned the energy in a particulartime-frequency bin. To overcome this problem, we reformulate the classical pan-pot source separationproblem for music sources as a non-negative quadratic program. This reformulation gives rise toan algorithm, called Redress, which extends the popular Adress algorithm. It works by definingan azimuth trajectory for each source based on …


Optimal Sizing Of Energy Storage With Embedded Wind Power Generation, Nicholas Roche, Jane Courtney Jan 2020

Optimal Sizing Of Energy Storage With Embedded Wind Power Generation, Nicholas Roche, Jane Courtney

Articles

Energy storage technologies are key to increased penetration of renewable energies on the distribution system. Not only do they increase availability of energy, but they contribute to the overall reliability of the system. However, the cost of large-scale storage systems can often be prohibitive, and storage needs to be sized appropriately, both to fill the energy gaps inevitable in renewable energies such as wind and to minimize costs. In this work, a Monte Carlo Simulation is performed to optimally size an energy storage system while minimizing overall system cost. 30 years of historical wind speed data are used to model …


Investigation On The Polarization Dependence Of An Angled Polished Multimode Fibre Structure, Ruoning Wang, Ke Tian, Meng Zhang, Yuxuan Jiang, Libo Yuan, Guoyong Jin, Gerald Farrell, Elfed Lewis, Pengfei Wang Jan 2020

Investigation On The Polarization Dependence Of An Angled Polished Multimode Fibre Structure, Ruoning Wang, Ke Tian, Meng Zhang, Yuxuan Jiang, Libo Yuan, Guoyong Jin, Gerald Farrell, Elfed Lewis, Pengfei Wang

Articles

An angled polished multimode (APM) fibre structure is described for the first time, to the best our knowledge, and its polarization dependence is investigated theoretically and experimentally. Two angled planes are established in the multimode fibre (MMF) section of a single-mode-multimode-single-mode (SMS) fibre structure using the fibre side-polishing technique, forming the APM fibre structure. This designed circular asymmetric geometry induces different propagation characteristics for the TE and TM modes within the MMF. Simulated and experimental results both show that this difference is enhanced as the polishing angle increases, and a maximum extinction ratio (ER) of the spectrum of 13 dB …


Color Variation Of The Up-Conversion Luminescence In Er3+-Yb3+Co-Doped Lead Germanate Glasses And Microsphere Integrated Devices, Meng Zhang, Ke Tian, Shunbin Wang, Libo Yuan, Gerald Farrell, Elfed Lewis, Pengfei Wang Jan 2020

Color Variation Of The Up-Conversion Luminescence In Er3+-Yb3+Co-Doped Lead Germanate Glasses And Microsphere Integrated Devices, Meng Zhang, Ke Tian, Shunbin Wang, Libo Yuan, Gerald Farrell, Elfed Lewis, Pengfei Wang

Articles

Abstract—Lead germanate glass samples co-doped with different Er3+/Yb3+ concentrations were prepared and the color variation of the up-conversion emissions in these glasses was observed using a 980 nm laser pump. A practical optical integrated device based on Er3+ -Yb3+ co-doped lead germanate glass microsphere and a special fiber structure, consisting of single mode fiber (SMF), multimode fiber (MMF) and a suspended tricore hollow fiber (STCHF) is described. As the pump light is coupled into the microsphere from the cores suspended inside the STCHF, the microsphere fixed in the air hole of the STCHF is excited and the up-conversion emissions are …


A Closed-Loop Renewable Energy Evaluation Framework, Tony Kealy Jan 2020

A Closed-Loop Renewable Energy Evaluation Framework, Tony Kealy

Articles

Many businesses that have embraced renewable energy projects as part of their corporate sustainability efforts lack direction concerning how the projects are assessed. This study presents a framework that prescribes the necessary stages that allow a robust project evaluation to take place. The framework should assist practitioners in ascertaining if renewable energy projects, such as wind turbines and hydroelectric generators, contribute to energy cost savings and a reduction in CO2 emissions. The conceptual framework was developed using empirical data accessed from an 850-kW wind turbine case study and a 40-kW hydro-electric case study and embraced the action research methodology. Both …


Crystal-Field Engineering Of Ultrabroadband Mid-Infrared Emission In Co2+-Doped Nano-Chalcogenide Glass Composites, Xiasong Lu, Runan Zhang, Yindong Zhang, Shaoqian Zhang, Jing Ren, Lukas Strizik, Thomas Wagner, Gerald Farrell, Pengfei Wang Jan 2020

Crystal-Field Engineering Of Ultrabroadband Mid-Infrared Emission In Co2+-Doped Nano-Chalcogenide Glass Composites, Xiasong Lu, Runan Zhang, Yindong Zhang, Shaoqian Zhang, Jing Ren, Lukas Strizik, Thomas Wagner, Gerald Farrell, Pengfei Wang

Articles

unable and ultrabroadband mid-infrared (MIR) emissions in the range of 2.5–4.5 μm are firstly reported from Co2+-doped nano-chalcogenide (ChG) glass composites. The composites embedded with a variety of binary (ZnS, CdS, ZnSe) and ternary (ZnCdS, ZnSSe) ChG nanocrystals (NCs) can be readily obtained by a simple one-step thermal annealing method. They are highly transparent in the near- and mid-infrared wavelength region. Low-cost and commercially available Er3+-doped fiber lasers can be used as the excitation source. By crystal-field engineering of the embedded NCs through cation- or anion-substitution, the emission properties of Co2+ including its emission peak wavelength and bandwidth can be …


Impact Assessment Of High-Power Domestic Ev Charging Proliferation Of A Distribution Network, Arsalan Zaidi, Keith Sunderland, Michael Conlon Jan 2020

Impact Assessment Of High-Power Domestic Ev Charging Proliferation Of A Distribution Network, Arsalan Zaidi, Keith Sunderland, Michael Conlon

Articles

Transport electrification is becoming the mainstream as a means to improve efficiency, performance, andsustainability of transportation systems. Electrical vehicles (EVs) can help to de-carbonise the environment, but a downside isthe technical issues presented to the low-voltage distribution network. To quantify the stochastic nature of transport-affectedelectrification, probabilistic load flow is employed. Monte Carlo-based simulation is applied to accommodate the probabilisticuncertainties associated with variable EV charging patterns. This study considers high-power charging (up to 11 kW) at thedomestic level while monitoring power quality variations (voltage drop, voltage unbalance factor, voltage sag) standards. Thiswork focuses on the Irish and UK, distribution system operator's–transmission …


A Wide Frequency Scanning Printed Bruce Array Antenna With Bowtie And Semi-Circular Elements, Zeeshan Ahmed, Patrick Mcevoy, Max Ammann Jan 2020

A Wide Frequency Scanning Printed Bruce Array Antenna With Bowtie And Semi-Circular Elements, Zeeshan Ahmed, Patrick Mcevoy, Max Ammann

Articles

A printed edge-fed counterpart of the wire Bruce array antenna, for frequency scanning applications, is presented in this paper. The unit-cell of the proposed antenna consists of bowtie and semi-circular elements to achieve wide bandwidth from below 22 GHz to above 38 GHz with open-stopband suppression. The open-stopband suppression enables a wide seamless scanning range from backward, through broadside, to forward endfire. A sidelobe threshold level of −10 dB is maintained to evaluate efficient scanning performance of the antenna. The antenna peak realized gain is 15.30 dBi, and, due to its compact size, has the ability to scan from −64° …


Anti-Resonance, Inhibited Coupling And Mode Transitionin Depressed Core Fibers, Xiaokang Lian, Gerald Farrell, Qiang Wu, Wei Han, Changyu Shen, Youqiao Ma, Yuliya Semenova Jan 2020

Anti-Resonance, Inhibited Coupling And Mode Transitionin Depressed Core Fibers, Xiaokang Lian, Gerald Farrell, Qiang Wu, Wei Han, Changyu Shen, Youqiao Ma, Yuliya Semenova

Articles

The depressed core fiber (DCF), consisting of a low-index solid core, a high-index cladding and air surrounding, is in effect a bridge between the conventional step-index fiber and the tube-type hollow-core fiber from the point of view of the index profile. In this paper the dispersion diagram of a DCF is obtained by solving the full-vector eigenvalue equations and analyzed using the theory of anti-resonant and the inhibited coupling mechanisms. While light propagation in tube-type hollow-core fibers is commonly described by the symmetric planar waveguide model, here we propose an asymmetric planar waveguide for the DCFs in an anti-resonant reflecting …


Application Of Demand Response To Improve Voltage Regulation With High Dg Penetration, Chittesh Veni Chandran, Malabika Bassu, Keith Sunderland, Shivananda Pukhrem, João Catalão Jan 2020

Application Of Demand Response To Improve Voltage Regulation With High Dg Penetration, Chittesh Veni Chandran, Malabika Bassu, Keith Sunderland, Shivananda Pukhrem, João Catalão

Articles

The ability of a consumer friendly demand response based voltage control (DR-VC) program to improve the voltage regulation in a low voltage distribution network (LVDN) with high penetration of DG is investigated. The use of active and reactive power management to regulate the nodal voltage in a distribution network with simple incremental reduction algorithm, in conjunction with DR, is proposed as a solution for over voltage and undervoltage issues in the LVDN. The algorithm micromanages the load and generation in the network enabling the operator to utilize grid resources economically and efficiently while maintaining fairness between consumers with minimum inconvenience. …


The Effect Of High Background And Dead Time Of An Ingaas/Inp Single-Photon Avalanche Photodiode On The Registration Of Microsecond Range Near-Infrared Luminescence, P. S. Parfenov, A. P. Litvin, D. A. Onishchuk, K. A. Gonchar, Kevin Berwick, A. V. Fedorov, A. V. Baranov Jan 2020

The Effect Of High Background And Dead Time Of An Ingaas/Inp Single-Photon Avalanche Photodiode On The Registration Of Microsecond Range Near-Infrared Luminescence, P. S. Parfenov, A. P. Litvin, D. A. Onishchuk, K. A. Gonchar, Kevin Berwick, A. V. Fedorov, A. V. Baranov

Articles

The effects of a high background count and a microsecond dead time interval on a gated InGaAs/InP single-photon avalanche photodiode (SPAD) during microsecond luminescence decay registration are discussed. It is shown that the background count rate of the SPAD limits its use for time-resolved and steady-spectral measurements, and that a “pile-up” effect appears in the microsecond range.