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2017

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Full-Text Articles in Electrical and Computer Engineering

Magnetic Field Sensor Based On A Combination Of A Microfiber Coupler Covered With Magnetic Fluid And A Sagnac Loop, Fangfang Wei, Arun Mallik, Dejun Liu, Qiang Wu, Gang-Ding Peng, Gerald Farrell, Yuliya Semenova Jul 2017

Magnetic Field Sensor Based On A Combination Of A Microfiber Coupler Covered With Magnetic Fluid And A Sagnac Loop, Fangfang Wei, Arun Mallik, Dejun Liu, Qiang Wu, Gang-Ding Peng, Gerald Farrell, Yuliya Semenova

Articles

This paper proposes a novel magnetic field sensor based on a microfiber coupler (MFC) combined with a magnetic fluid (MF) in a Sagnac loop formed from a polarization maintaining fiber (PMF). Thanks to the small (~2.6μm) waist diameter of the MFC, the resulting interference is strongly influenced by the presence of the MF and this leads to the desirable high sensitivity of the structure to the applied magnetic field. The maximum magnetic field sensitivities of −100pm/mT and −488pm/mT have been experimentally demonstrated with the PMF lengths of 75cm and 20cm respectively in the range of magnetic field strengths from 0 …

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Broadband Acoustic Measurement Of The Agar-Based Tissue Mimicking Material – A Longitudinal Study, Adela Rabell-Montiel, Jacinta Browne, Stephen Pye, Tom Anderson, Carmel Moran Jul 2017

Broadband Acoustic Measurement Of The Agar-Based Tissue Mimicking Material – A Longitudinal Study, Adela Rabell-Montiel, Jacinta Browne, Stephen Pye, Tom Anderson, Carmel Moran

Articles

Commercially available ultrasound quality assurance test phantoms rely upon the long-term acoustic stability of tissue-mimicking-materials (TMMs). The measurement of the acoustic properties can be technically challenging and it is important to ensure its stability. The standard technique is to film-wrap samples of TMM and to measure the acoustic properties in a water bath. In this study, a modified technique is proposed whereby the samples of TMM are measured in a preserving fluid that is intended to maintain their characteristics. The acoustic properties were evaluated using a broadband pulse-echo substitution technique over the frequency range of 4.5 – 50 MHz at …

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Stakeholder Outcomes In A Wind Turbine Investment; Is The Irish Energy Policy Effective In Reducing Ghg Emissions By Promoting Small-Scale Embedded Turbines In Sme's?, Tony Kealy Feb 2017

Stakeholder Outcomes In A Wind Turbine Investment; Is The Irish Energy Policy Effective In Reducing Ghg Emissions By Promoting Small-Scale Embedded Turbines In Sme's?, Tony Kealy

Articles

As a member state of the European Union (EU), Ireland has adopted an energy policy which includes promoting wind powered electricity generators as an economically viable, GHG-reducing, alternative to environmentally damaging fossil-fuel driven electrical generators. This longitudinal, inductive in-depth study investigates the outcomes for the government and other stakeholders involved in a wind turbine project investment by a Small-to-Medium-Enterprise (SME) based in rural Ireland. A case study research methodology is used to acquire and analyse quantitative numerical data from multiple sources including electrical power and energy meters, historical electricity bills and company sustainability reports. The study found that the installation …

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Determination Of Reliable Fatigue Life Predictors For Magnetorheological Elastomers Under Dynamic Equi-Biaxial Loading, Yangen Zhou, Liang Jiang, Shaojuan Chen, Jianwei Ma, Tony Betts, Stephen Jerrams Jan 2017

Determination Of Reliable Fatigue Life Predictors For Magnetorheological Elastomers Under Dynamic Equi-Biaxial Loading, Yangen Zhou, Liang Jiang, Shaojuan Chen, Jianwei Ma, Tony Betts, Stephen Jerrams

Articles

Fatigue life prediction is of great significance in ensuring magnetorheological elastomer (MRE) based rubber components exhibit reliability and do not compromise safety under complex loading and this necessitates the development of plausible fatigue life predictors for MREs. In this research, silicone rubber based MREs were fabricated by incorporating soft carbonyl iron magnetic particles. Equi-biaxial fatigue behaviour of the fabricated MREs was investigated by using the bubble inflation method. The relationship between fatigue life and maximum engineering stress, maximum strain and strain energy density were studied. The results showed that maximum engineering stress and stored energy density can be used as …

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Characterization Of The Sub-Micrometer Hierarchy Levels In The Twist-Bend Nematic Phase With Nanometric Helices Via Photopolymerization: Explanation For The Sign Reversal In The Polar Response, Vitaly Panov, Sithara Sreenilayam, Yuri Panarin, Jagdish Vij, Chris Welch, Georg Mehl Jan 2017

Characterization Of The Sub-Micrometer Hierarchy Levels In The Twist-Bend Nematic Phase With Nanometric Helices Via Photopolymerization: Explanation For The Sign Reversal In The Polar Response, Vitaly Panov, Sithara Sreenilayam, Yuri Panarin, Jagdish Vij, Chris Welch, Georg Mehl

Articles

Photopolymerization of a reactive mesogen mixed with a mesogenic dimer, shown to exhibit the twist-bend nematic phase (NTB), reveals the complex structure of the self-deformation patterns observed in planar cells. The polymerized reactive mesogen retains the structure formed by liquid crystalline molecules in the twist bend phase, thus enabling its observation by scanning electron microscopy (SEM). Hierarchical ordering scales ranging from tens of nanometers to micrometers are imaged in detail. Submicron features, anticipated from earlier X-ray experiments, are visualized directly. In the self-deformation stripes formed in the NTB phase, the average director field is found tilted in …

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Hybrid Graphene–Copper Uwb Array Sensor For Brain Tumor Detection Via Scattering Parameters In Microwave Detection System, Mohd Aminudin Jamlos, Abdul Hafiizh Ismail, Mohd Faizal Jamlos, Adam Narbudowicz Jan 2017

Hybrid Graphene–Copper Uwb Array Sensor For Brain Tumor Detection Via Scattering Parameters In Microwave Detection System, Mohd Aminudin Jamlos, Abdul Hafiizh Ismail, Mohd Faizal Jamlos, Adam Narbudowicz

Articles

Hybrid graphene–copper ultra-wideband array sensor applied to microwave imaging technique is successfully used in detecting and visualizing tumor inside human brain. The sensor made of graphene coated film for the patch while copper for both the transmission line and parasitic element. The hybrid sensor performance is better than fully copper sensor. Hybrid sensor recorded wider bandwidth of 2.0–10.1 GHz compared with fully copper sensor operated from 2.5 to 10.1 GHz. Higher gain of 3.8–8.5 dB is presented by hybrid sensor, while fully copper sensor stated lower gain ranging from 2.6 to 6.7 dB. Both sensors recorded excellent total efficiency averaged …

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Multi-Band Antenna Array Based On Double Negative Metamaterial For Multi Automotive Applications, Mohd Jamlos, Abdulrahman Alqadami,, Imtiaz Islam, Ping Soh, Rizalman Mamat, Khairil Khairi, Adam Narbudowicz Jan 2017

Multi-Band Antenna Array Based On Double Negative Metamaterial For Multi Automotive Applications, Mohd Jamlos, Abdulrahman Alqadami,, Imtiaz Islam, Ping Soh, Rizalman Mamat, Khairil Khairi, Adam Narbudowicz

Articles

Nowadays, the demand for antennas in wireless communication system for automotive applications is rising at a rapid rate [1, 2]. Their usage includes collision avoidance system (CAS), Vehicle-to-vehicle communications, pre-crash safety systems, Global Positioning Systems (GPS), tyre pressure monitoring system (TPMS), Wireless Local Area Network (WLAN), etc. To enhance its effectiveness in these new applications, a small, multi-band, multi-functional antenna is required instead of conventional single band antennas [2, 3]. Such multifunctional antennas with favourable radiation characteristics are more practical in addressing modern antenna design requirements. However, the achievement of the above mentioned antenna’s features using conventional materials and structures …

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Reneb - Running The European Network Of Biological Dosimetry And Physical Retrospective Dosimetry, Ulrike Kulka, Michael Abend, Liz Ainsbury, Christophe Badie, Joan-Francesc Barquinero, Leonardo Barrios, Christina Beinke, Emanuela Bortolin, Alexandra Cucu, Fiona Lyng Jan 2017

Reneb - Running The European Network Of Biological Dosimetry And Physical Retrospective Dosimetry, Ulrike Kulka, Michael Abend, Liz Ainsbury, Christophe Badie, Joan-Francesc Barquinero, Leonardo Barrios, Christina Beinke, Emanuela Bortolin, Alexandra Cucu, Fiona Lyng

Articles

Purpose: A European network was initiated in 2012 by 23 partners from 16 European countries with the aim to significantly increase individualized dose reconstruction in case of large-scale radiological emergency scenarios.

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A Packaged Whispering Gallery Mode Strain Sensor Based On A Polymer Wire Cylindrical Micro Resonator, Vishnu Kavungal, Gerald Farrell, Qiang Wu, Arun Mallik, Yuliya Semenova Jan 2017

A Packaged Whispering Gallery Mode Strain Sensor Based On A Polymer Wire Cylindrical Micro Resonator, Vishnu Kavungal, Gerald Farrell, Qiang Wu, Arun Mallik, Yuliya Semenova

Articles

We propose a whispering gallery mode (WGM) strain sensor formed by a polymer-wire cylindrical micro resonator for strain measurement applications. WGMs are generated by evanescently coupling light into the polymer-wire resonator from a silica fiber taper fabricated by the micro heater brushing technique. Accurate and repeatable measurements of a strains up to one free spectral range (FSR) shift of the WGMs (corresponding to 0.33 % of the polymer-wire elongation, 3250 μɛ) are demonstrated experimentally with the proposed sensor. Practical packaging method for the proposed strain sensor on a glass microscope slide has also been realized making the sensor portable and …

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Adaptive Linear Prediction For Optimal Control Of Wind Turbines, Mahinsasa Narayana, Keith Sunderland, Ghanim Putrus, Michael Conlon Jan 2017

Adaptive Linear Prediction For Optimal Control Of Wind Turbines, Mahinsasa Narayana, Keith Sunderland, Ghanim Putrus, Michael Conlon

Articles

In order to obtain maximum power output of a Wind Energy Conversion System (WECS), the rotor speed needs to be optimised for a particular wind speed. However, due to inherent inertia, the rotor of a WECS cannot react instantaneously according to wind speed variations. As a consequence, the performance of the system and consequently the wind energy conversion capability of the rotor are negatively affected. This study considers the use of a time series Adaptive Linear Prediction (ALP) technique as a means to improve the performance and conversion efficiency of wind turbines. The ALP technique is introduced as a real …

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Carbon Nanomaterials And Their Application To Electrochemical Sensors: A Review, Aoife Power, Shaneel Chandra, Brian Gorey, James Chapman Jan 2017

Carbon Nanomaterials And Their Application To Electrochemical Sensors: A Review, Aoife Power, Shaneel Chandra, Brian Gorey, James Chapman

Articles

Carbon has long been applied as an electrochemical sensing interface owing to its unique electrochemical properties. Moreover, recent advances in material design and synthesis, particularly nanomaterials, has produced robust electrochemical sensing systems that display superior analytical performance. Carbon nanotubes (CNTs) are one of the most extensively studied nanostructures because of their unique properties. In terms of electroanalysis, the ability of CNTs to augment the electrochemical reactivity of important biomolecules and promote electron transfer reactions of proteins is of particular interest. The remarkable sensitivity of CNTs to changes in surface conductivity due to the presence of adsorbates permits their application as …

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Strain Sensor Based On Grourd-Shaped Single-Mode-Multimode-Single-Mode Hybrid Optical Fibre Structure, Ke Tian, Gerald Farrell, Xianfan Wang, Wenlei Yang, Yifan Xin, Haidong Liang, Elfed Lewis, Pengfei Wang Jan 2017

Strain Sensor Based On Grourd-Shaped Single-Mode-Multimode-Single-Mode Hybrid Optical Fibre Structure, Ke Tian, Gerald Farrell, Xianfan Wang, Wenlei Yang, Yifan Xin, Haidong Liang, Elfed Lewis, Pengfei Wang

Articles

A fibre-optic strain sensor based on a gourd-shaped joint multimode fibre (MMF) sandwiched between two single-mode fibres (SMFs) is described both theoretically and experimentally. The cladding layers of the two MMFs are reshaped to form a hemisphere using an electrical arc method and spliced together, yielding the required gourd shape. The gourd-shaped section forms a Fabry-Perot cavity between the ends of two adjacent but noncontacting multimode fibres’ core. The effectiveness of the multimode interference based on the Fabry-Perot interferometer (FPI) formed within the multimode inter-fibre section is greatly improved resulting in an experimentally determined strain sensitivity of −2.60 pm/με over …

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A Curvature Sensor Based On Twisted Single-Mode-Multimode-Single-Mode Hybrid Optical Fiber Structure, Ke Tian, Yifan Xin, Wenlei Yang, Tao Geng, Jing Ren, Ya-Xian Fan, Gerald Farrell, Elfed Lewis, Pengfei Wang Jan 2017

A Curvature Sensor Based On Twisted Single-Mode-Multimode-Single-Mode Hybrid Optical Fiber Structure, Ke Tian, Yifan Xin, Wenlei Yang, Tao Geng, Jing Ren, Ya-Xian Fan, Gerald Farrell, Elfed Lewis, Pengfei Wang

Articles

An optical fiber curvature sensor based on a twisted multimode fiber (MMF) sandwiched between two single-mode fibers (SMF) is proposed and investigated theoretically and experimentally. The measured transmission spectrum exhibits good agreement with theoretical predictions. Compared with a traditional single-mode-multimode-single-mode fiber structure sensor, the proposed configuration offers a higher average curvature sensitivity of -2.42 nm/m -1 over a curvature measurement range of 0-1.7390 m -1 and -7.09 dB/m -1 at an operating wavelength of 1537 nm. The temperature sensitivity of this sensor has been determined as 0.01 nm/°C over a wavelength range of 1535-1550 nm and circa 0.007 dB/°C at …

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Investigation Of The Self-Imaging Position Of A Singlemode-Multimode-Singlemode Optical Fiber Structure, Xianfan Wang, Elfed Lewis, Pengfei Wang Jan 2017

Investigation Of The Self-Imaging Position Of A Singlemode-Multimode-Singlemode Optical Fiber Structure, Xianfan Wang, Elfed Lewis, Pengfei Wang

Articles

In this paper, a theoretical and experimental investigation of the multimode interference induced self-imaging phenomenon in a singlemode-multimode-singlemode (SMS) fiber structure is described. The simulated transmission spectra based on guided modal propagation analysis and beam propagation method are presented and compared with experimental obtained results. The temperature dependence of the self-imaging position of the SMS fiber structure is also investigated. These investigations provide excellent opportunities for multiple future applications including telecommunications and sensing.

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A Chalcogenide Multimode Interferometric Temperature Sensor Operating At A Wavelength Of 2 Μm, Lin She, Pengfei Wang, Weimin Sun, Xianfan Wang, Wenlei Yang, Gilberto Brambilla, Gerald Farrell Jan 2017

A Chalcogenide Multimode Interferometric Temperature Sensor Operating At A Wavelength Of 2 Μm, Lin She, Pengfei Wang, Weimin Sun, Xianfan Wang, Wenlei Yang, Gilberto Brambilla, Gerald Farrell

Articles

This paper investigated the fabrication of a singlemode-multimode-singlemode fiber structure based on a chalcogenide (As2S3 and AsxS1−x) multimode fiber sandwiched between two standard silica singlemode fibers using a commercial fiber fusion splicer. The temperature dependence of this hybrid fiber structure was investigated and a first proof of concept showed that the hybrid SMS fiber structure has an average experimental temperature sensitivity of circa 84.38 pm/°C over a temperature range of 20 °C∼100°C at the wavelength range around 2 μm. The measured results show a general agreement with numerical simulations based on a guided-mode propagation analysis method. Our result provides a …

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Directional Modulation For Compact Devices, Adam Narbudowicz Jan 2017

Directional Modulation For Compact Devices, Adam Narbudowicz

Articles

A new directional modulation system which uses radiation pattern data for modulation encoding is proposed. The approach allows compact multiport antennas (e.g. MIMO capable antennas) to be used for directional modulation, replacing extensive arrays. The modulation weighting coefficients are calculated with a fixed, antenna specific equation, thus reducing computational complexity. The solution is intended to enhance privacy in small, battery-operated wireless devices, required for “Internet of Things” applications.

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Design Of A Compact, Fully-Autonomous 433 Mhz Tunable Antenna For Wearable Wireless Sensor Applications, John Buckley, Kevin Mccarthy, Domenico Gaetano, Loizos Loizou, Brendan O'Flynn, Cian O'Mathuna Jan 2017

Design Of A Compact, Fully-Autonomous 433 Mhz Tunable Antenna For Wearable Wireless Sensor Applications, John Buckley, Kevin Mccarthy, Domenico Gaetano, Loizos Loizou, Brendan O'Flynn, Cian O'Mathuna

Articles

The authors present the design of a tunable 433 MHz antenna that is tailored for wearable wireless sensor applications. This study first presents a detailed analysis of the measured impedance characteristics of a chosen antenna under test (AUT) in varying proximity to a human test subject. Instead of limiting the analysis to the head and hand only, this analysis measures the AUT impedance at varying distances from 11 different body positions. A novel antenna equivalent circuit model is then developed that enables both the free-space and total on-body AUT impedance variation to be rapidly computed using a circuit simulator instead …

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Glass-Ceramic Optical Fiber Containing Ba2 Tisi2o8 Nanocrystals For Frequency Conversion Of Lasers, Zaijin Fang, Xusheng Xiao, Xin Wang Xin Wang, Zhijun Ma, Elfed Lewis, Gerald Farrell, Pengfei Wang, Jing Ren, Haitao Guo, Jianrong Qiu Jan 2017

Glass-Ceramic Optical Fiber Containing Ba2 Tisi2o8 Nanocrystals For Frequency Conversion Of Lasers, Zaijin Fang, Xusheng Xiao, Xin Wang Xin Wang, Zhijun Ma, Elfed Lewis, Gerald Farrell, Pengfei Wang, Jing Ren, Haitao Guo, Jianrong Qiu

Articles

A glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba2TiSi2O8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic …

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The Effect Of The Local Field And Dipole-Dipole Interactions On The Absorption Spectra Of Noble Metals And The Plasmon Resonance Of Their Nanoparticles, I.I. Shaganov, T.S. Perova, Kevin Berwick Jan 2017

The Effect Of The Local Field And Dipole-Dipole Interactions On The Absorption Spectra Of Noble Metals And The Plasmon Resonance Of Their Nanoparticles, I.I. Shaganov, T.S. Perova, Kevin Berwick

Articles

An analysis of the effect of free and bound electrons on the optical properties of noble metals and their nanoparticles is performed, based on the Drude-Lorentz model. It is shown that the shifts in the absorption bands of plasmons localized in spherical nanoparticles with respect to the zero frequency of free electrons in a bulk metal can be estimated using the theory of resonant dipole-dipole interactions. The calculation includes account for differences between the effective and average electromagnetic fields. It is established that the difference in oscillator strength for free electrons in the bulk metal, obtained using the Drude-Lorentz model, …

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Selective Doping Of Ni2+ In Highly Transparent Glass-Ceramics Containing Nano-Spinels Znga2o4 And Zn1+Xga2−2xgexo4 For Broadband Near-Infrared Fiber Amplifiers, Zhigang Gao, Yinyao Liu, Jing Ren, Zaijin Fang, Xiaosong Lu, Elfed Lewis, Gerald Farrell, Jun Yang, Pengfei Wang Jan 2017

Selective Doping Of Ni2+ In Highly Transparent Glass-Ceramics Containing Nano-Spinels Znga2o4 And Zn1+Xga2−2xgexo4 For Broadband Near-Infrared Fiber Amplifiers, Zhigang Gao, Yinyao Liu, Jing Ren, Zaijin Fang, Xiaosong Lu, Elfed Lewis, Gerald Farrell, Jun Yang, Pengfei Wang

Articles

Selective doping of Ni2+ in octahedral sites provided by nanocrystals embedded in glass-ceramics (GCs) is crucial to the enhancement of broadband near-infrared (NIR) emission. In this work, a NIR emission with a full-width-at-half-maximum (FWHM) of 288 nm is first reported from ZnGa2O4: Ni2+ nano-spinels embedded GCs with excellent transparency. A comparison is made of the NIR luminescence properties of Ni2+ doped GCs containing ZnGa2O4, germanium-substituted ZnGa2O4 nano-spinels (Zn1+xGa2−2xGexO4), and Zn2GeO4/Li2Ge4O9 composite nanocrystals that are free of Ga3+. The results show that ZnGa2O4: Ni2+ GCs exhibit a significantly enhanced NIR emission. The incorporation of the nucleating agent TiO2 is favored in …

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The Electrochemical Deposition Of Zn-Mn Coating From Choline Choloride-Urea Deep Eutectic Solvent, Mihael Bucko, David Culliton, Tony Betts, Jelena Bajat Jan 2017

The Electrochemical Deposition Of Zn-Mn Coating From Choline Choloride-Urea Deep Eutectic Solvent, Mihael Bucko, David Culliton, Tony Betts, Jelena Bajat

Articles

Electrochemical and microscopic techniques were used for characterization of Zn˗Mn coatings electrodeposited from choline chloride˗urea deep eutectic solvent. Cyclic voltammograms show that there was no discernible Mn reduction peak when only Mn2+ was present in DES solution. The distinct Mn peak developed only upon addition of Zn2+ to the solution, probably due to previous Zn nucleation on the steel substrate. It was found that 22-27 wt.% Mn, was deposited at current densities of 3-8 mA cm-2, amounts significantly higher than in aqueous electrolytes. Since higher deposition current densities resulted in the formation of a porous surface consisting of clusters of …

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Passive Photonic Integrated Ratiometric Wavelength Monitor With Resolution Better Than 15pm, Pengfei Wang, Agus Muhamad Hatta, Haoyu Zhao, Wenlei Yang, Jing Ren, Yaxian Fan, Gerald Farrell, Gilberto Bramilla Jan 2017

Passive Photonic Integrated Ratiometric Wavelength Monitor With Resolution Better Than 15pm, Pengfei Wang, Agus Muhamad Hatta, Haoyu Zhao, Wenlei Yang, Jing Ren, Yaxian Fan, Gerald Farrell, Gilberto Bramilla

Articles

This paper presents a compact and low-loss photonic integrated device consisting of a Y-branch and a pair of multimode interferometers (MMI) for a ratiometric wavelength monitoring around 1550 nm on silicon-on-insulator (SOI) technique. Two MMIs are designed in terms of width and length to achieve overlapping but opposite slope spectral responses used as two edge filters over a wavelength measurement range from 1500 nm to 1600 nm. The developed integrated photonic ratiometric structure demonstrates a suitable discrimination range for a high-speed passive wavelength measurement, with a high resolution better than 15 pm over a 100 nm wavelength range.

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Enhanced Network Voltage Management (Nvm) Techniques Under The Proliferation Of Rooftop Solar Pv Installation In Low Voltage Distribution Network (Lvdn), Shivananda Pukhrem, Malabika Basu, Michael Conlon, Keith Sunderland Jan 2017

Enhanced Network Voltage Management (Nvm) Techniques Under The Proliferation Of Rooftop Solar Pv Installation In Low Voltage Distribution Network (Lvdn), Shivananda Pukhrem, Malabika Basu, Michael Conlon, Keith Sunderland

Articles

Proliferation of rooftop solar PV distributed generator (PVDG) installation in low voltage distribution network (LVDN) imposes voltage fluctuation challenges that are a threat to distribution system operators. Reactive power control (RPC) methods are insufficient in isolation to combat the overvoltage fluctuations manifested in LVDN with significant grid-tied PVDG installations. Whereas active power curtailment (APC) control can alleviate the voltage fluctuation in such situations and it is achieved at the cost of reduced active power injection. This paper explores how deficiencies in both RPC and APC as separate approaches can be mitigated by suitably combining RPC and APC algorithms. Strategies combining …

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Design And Investigation Of De Vries Liquid Crystals Based On 5-Phenyl-Pyrimidine And (R,R)-2,3-Epoxyhexoxy Backbone., S.P. Sreenilayam", D. Rodriguez-Lojo, V. P. Panov, V. Swaminathan, J. K. Vij, Yuri Panarin, E. Gorecka, A. Panov, P.J. Stevenson Jan 2017

Design And Investigation Of De Vries Liquid Crystals Based On 5-Phenyl-Pyrimidine And (R,R)-2,3-Epoxyhexoxy Backbone., S.P. Sreenilayam", D. Rodriguez-Lojo, V. P. Panov, V. Swaminathan, J. K. Vij, Yuri Panarin, E. Gorecka, A. Panov, P.J. Stevenson

Articles

Calamitic liquid crystals based on 5-phenyl-pyrimidine derivatives have been designed, synthesized, and characterized. The 5-phenyl pyrimidine core was functionalized with a chiral (R,R)-2,3-epoxyhexoxy chain on one side and either siloxane or perfluoro terminated chains on the opposite side. The one involving a perfluorinated chain shows SmA^{*} phase over a wide temperature range of 82 °C, whereas the siloxane analog exhibits both SmA^{*} and SmC^{*} phases over a broad range of temperatures, and a weak first-order SmA^{*}-SmC^{*} transition is observed. For the siloxane analog, the reduction factor for the layer shrinkage R (relative to its thickness at the SmA^{*}-SmC^{*} transition temperature, …

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Miniaturized Dual-Band Antenna Array With Double-Negative (Dng) Metamaterial For Wireless Applications, Abdulrahman Shueai Mohsen Alqadami, Mohd Faizal Jamlos, Ping Jack Soh, Sharul Kamal Abdul Rahim, Guy Vandenbosch, Adam Narbudowicz Jan 2017

Miniaturized Dual-Band Antenna Array With Double-Negative (Dng) Metamaterial For Wireless Applications, Abdulrahman Shueai Mohsen Alqadami, Mohd Faizal Jamlos, Ping Jack Soh, Sharul Kamal Abdul Rahim, Guy Vandenbosch, Adam Narbudowicz

Articles

A miniaturized dual-band antenna array using a negative index metamaterial is presented for WiMAX, LTE, and WLAN applications. This left-handed metamaterial plane is located behind the antenna array, and its unit cell is a combination of split-ring resonator, square electric ring resonator, and rectangular electrical coupled resonator. This enables the achievement of a metamaterial structure exhibiting both negative permittivity and permeability, which results in antenna size miniaturization, efficiency, and gain enhancement. Moreover, the proposed metamaterial antenna has realized dual-band operating frequencies compared to a single frequency for normal antenna. The measured reflection coefficient (S11) shows a 50.25% bandwidth in the …

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Grid Voltage Sensorless Single-Phase Half-Bridge Active Filter And Dc Bus Voltage Regulation, Samet Biricik Jan 2017

Grid Voltage Sensorless Single-Phase Half-Bridge Active Filter And Dc Bus Voltage Regulation, Samet Biricik

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In this paper, a method is presented for the control of grid voltage sensorless single-phase half-bridge shunt active power filter to reduce the grid current harmonics of low-power single-phase non-linear loads. The proposed system forces the grid current to be sinusoidal without sensing and processing the grid voltage on the line. For this reason, instead of grid voltage the load current is processed by using self-tuning filter to generate reference grid current to eliminate current harmonic distortions. In order to design a low-cost system, a half-bridge voltage source converter is used to reduce driver circuits. In addition, the switching losses …

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The Different Stages Of Prpd Pattern For Negative Point To Plane Corona Driven By A Dc Voltage Containing A Ripple, Tobias Dezenzo, Thomas Betz, Andreas Schwarzbacher Jan 2017

The Different Stages Of Prpd Pattern For Negative Point To Plane Corona Driven By A Dc Voltage Containing A Ripple, Tobias Dezenzo, Thomas Betz, Andreas Schwarzbacher

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This paper presents the different patterns, which can be observed by means of a phase resolved partial discharge analysis, when a negative dc voltage is applied to a point to plane arrangement in air. The required phase relation is obtained due to the ripple being present on the dc voltage generated by a half-wave rectification. Phase resolved partial discharge patterns are given from corona onset to glow inception. Discharge pulses appearing at the test object are used to support physical explanations of the pattern occurrence. It is shown that five clearly identifiable patterns accompany the evolution of corona discharges when …

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Time-Varying And Constant Switching Frequency-Based Sliding-Mode Control Methods For Transformerless Dvr Employing Half-Bridge Vsi, Hasan Komurcugil, Samet Biricik Jan 2017

Time-Varying And Constant Switching Frequency-Based Sliding-Mode Control Methods For Transformerless Dvr Employing Half-Bridge Vsi, Hasan Komurcugil, Samet Biricik

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This paper presents time-varying and constant switching frequency based sliding-mode control (SMC) methods for three-phase transformerless dynamic voltage restorers (TDVRs) which employ half-bridge voltage source inverter. An equation is derived for the time-varying switching frequency. However, since the time-varying switching frequency is not desired in practice, a smoothing operation is applied to the sliding surface function within a narrow boundary layer with the aim of eliminating the chattering effect and achieving a constant switching frequency operation. The control signal obtained from the smoothing operation is compared with a triangular carrier signal to produce the pulse width modulation signals. The feasibility …

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Nano-Magnetic Resonance Imaging (Nano-Mri) Gives Personalized Medicine A New Perspective, Lorenzo Rosa, Jonathan Blackledge, Albert Boretti Jan 2017

Nano-Magnetic Resonance Imaging (Nano-Mri) Gives Personalized Medicine A New Perspective, Lorenzo Rosa, Jonathan Blackledge, Albert Boretti

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This paper reviews some of the major and most recent advances in nanoscale-magnetic resonance imaging (nano-MRI) for personalized medicine (PM). Nano-MRI may drastically expand the capabilities of the traditional magnetic resonance images (MRI), down to the nanometer scale and possibly, in the near future, at the atomic scale. Nano-MRI is potentially able to observe structures which cannot be seen using today’s molecular imaging, with sensitivities of many billions of times better than MRI as currently used in hospitals, for example. The paper briefly reports on the foremost research themes in nano-MRI.

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Aphonic: Adaptive Thresholding For Noise Cancellation In Smart Mobile Environments, Ruairí De Fréin Jan 2017

Aphonic: Adaptive Thresholding For Noise Cancellation In Smart Mobile Environments, Ruairí De Fréin

Articles

We propose a signal-channel, adaptive threshold selection technique for binary mask construction, namely APHONIC, (AdaPtive tHreshOlding for NoIse Cancellation) for smart mobile environments. Using this mask, we introduce two noise cancellation techniques that perform robustly in the presence of real-world interfering signals that are typically encountered by mobile users: a violin busker, a subway and busy city square sounds. We demonstrate that when the power of the time-frequency components of the voice of a mobile user does not significantly overlap with the components of the interference signal, the threshold learning and noise cancellation techniques significantly improve the Signal-to-Interference Ratio (SIR) …

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