Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Optics (3)
- Applied Mathematics (2)
- Biological and Chemical Physics (2)
- Mathematics (2)
- Medicine and Health Sciences (2)
-
- Analytical, Diagnostic and Therapeutic Techniques and Equipment (1)
- Atomic, Molecular and Optical Physics (1)
- Chemistry (1)
- Condensed Matter Physics (1)
- Diagnosis (1)
- Diseases (1)
- Elementary Particles and Fields and String Theory (1)
- Fluid Dynamics (1)
- Materials Chemistry (1)
- Optometry (1)
- Partial Differential Equations (1)
- Virus Diseases (1)
- Keyword
-
- Holography (3)
- Amblyopia (1)
- Bangerter foils (1)
- Biomedical use (1)
- Black Holes (1)
-
- COVID-19 (1)
- Cavitation erosion (1)
- Chiral (1)
- Convalescing (1)
- Deep water model (1)
- Dielectric permittivity (1)
- Dielectric spectroscopy (1)
- Diffusers (1)
- Dirichlet-Neumann Operator (1)
- Electrode Kinetics (1)
- Electrolyte Stability (1)
- Ferroelectric nematics (1)
- Fiber optics (1)
- Field and String Theory models and techniques (1)
- Glutathione (1)
- Grating (1)
- Hamiltonian (1)
- Heat Transfer Fluid (1)
- Holographic diffusers (1)
- Holographic sensor (1)
- Holographic wavefront sensing (1)
- Human Serum (1)
- Hydrophobicity (1)
- Industrial control (1)
- KdV equation (1)
Articles 1 - 12 of 12
Full-Text Articles in Physics
Renormalized Stress-Energy Tensor For Scalar Fields In Hartle-Hawking, Boulware, And Unruh States In The Reissner-Nordström Spacetime, Julio Arrechea, Cormac Breen, Adrian Ottewill, Peter Taylor
Renormalized Stress-Energy Tensor For Scalar Fields In Hartle-Hawking, Boulware, And Unruh States In The Reissner-Nordström Spacetime, Julio Arrechea, Cormac Breen, Adrian Ottewill, Peter Taylor
Articles
In this paper, we consider a quantum scalar field propagating on the Reissner-Nordström black hole spacetime. We compute the renormalized stress-energy tensor for the field in the Hartle-Hawking, Boulware and Unruh states. When the field is in the Hartle-Hawking state, we renormalize using the recently developed “extended coordinate” prescription. This method, which relies on Euclidean techniques, is very fast and accurate. Once, we have renormalized in the Hartle-Hawking state, we compute the stress-energy tensor in the Boulware and Unruh states by leveraging the fact that the difference between stress-energy tensors in different quantum states is already finite. We consider a …
Raman Spectroscopic Analysis Of Human Serum Samples Of Convalescing Covid-19 Positive Patients, Hugh Byrne, Naomi Jackson, Jaythoon Hassan
Raman Spectroscopic Analysis Of Human Serum Samples Of Convalescing Covid-19 Positive Patients, Hugh Byrne, Naomi Jackson, Jaythoon Hassan
Articles
Rapid screening, detection and monitoring of viral infection is of critical importance, as exemplified by the rapid spread of SARS-CoV-2, leading to the worldwide pandemic of COVID-19. This is equally the case for the stages of patient convalescence as for the initial stages of infection, to understand the medium and long terms effects, as well as the efficacy of therapeutic interventions. Optical spectroscopic techniques potentially offer an alternative to currently employed techniques of screening for the presence, or the response to infection. In this study, the ability of Raman spectroscopy to distinguish between samples of the serum of convalescent COVID-19 …
Optical Characterisation Of Holographic Diffusers And Bangerter Foils For Treatment Of Amblyopia, Matthew Hellis, Suzanne Martin, Matthew Sheehan, Kevin Murphy
Optical Characterisation Of Holographic Diffusers And Bangerter Foils For Treatment Of Amblyopia, Matthew Hellis, Suzanne Martin, Matthew Sheehan, Kevin Murphy
Articles
Amblyopia is a significant issue for children worldwide, and current treatment methods have drawbacks that can hinder treatment effectiveness and/or patient experience. This study proposes a new treatment method using holographic diffusers while also comparing their optical characteristics to a current treatment method (Bangerter foils). Holographic diffusers were developed by optically patterning thin polymer layers on a micron scale. Two compositions of photopolymer (acrylamide and diacetone acrylamide based) are analysed herein. Characterisation shows that holographic diffusers of either composition can achieve a wide range of on-axis intensity reductions, allowing for precise and customisable treatment levels by altering recording exposure time …
Analog Holographic Wavefront Sensor For Defocus And Spherical Aberration Measurement Recorded In A Photopolymer, Emma Branigan, Suzanne Martin, Matthew Sheehan, Kevin Murphy
Analog Holographic Wavefront Sensor For Defocus And Spherical Aberration Measurement Recorded In A Photopolymer, Emma Branigan, Suzanne Martin, Matthew Sheehan, Kevin Murphy
Articles
An analog holographic wavefront sensor (AHWFS), for measurement of low and high order (defocus and spherical aberration) aberration modes has been developed as volume phase holograms in a photopolymer recording medium. This is the first time that high order aberrations such as spherical aberration can be sensed using a volume hologram in a photosensitive medium. Both defocus and spherical aberration were recorded in a multi-mode version of this AHWFS. Refractive elements were used to generate a maximum and minimum phase delay of each aberration which were multiplexed as a set of volume phase holograms in an acrylamide based-photopolymer layer. The …
Collective Relaxation Processes In Nonchiral Nematics, Neelam Yadav, Yuri Panarin, Wanhe Jiang, Georg H. Mehl, Jagdish Vij
Collective Relaxation Processes In Nonchiral Nematics, Neelam Yadav, Yuri Panarin, Wanhe Jiang, Georg H. Mehl, Jagdish Vij
Articles
Nematic–nematic transitions in a highly polar nematic compound are studied, in thick cells in which the molecules are aligned parallel to the substrates but perpendicular to the applied electric field, using dielectric spectroscopy in the frequency range 1 Hz to 10 MHz over a wide temperature range. The studied compound displays three nematic phases under cooling from the isotropic phase: ubiquitous nematic N; high polarizability NX; and ferroelectric nematic NF. Two collective processes were observed. The dielectric strength and relaxation frequency of one of the processes P2 showed a dependence on the thickness of the cell. The process P1 is …
Cavitation Erosion And Corrosion Resistance Of Hydrophobic Sol-Gel Coatings On Aluminium Alloy, Manasa Hegde, Joseph Mohan, Muhammad Qasim Mushtaq Warraich, Yvonne Kavanagh, Brendan Duffy, Edmond F. Tobin
Cavitation Erosion And Corrosion Resistance Of Hydrophobic Sol-Gel Coatings On Aluminium Alloy, Manasa Hegde, Joseph Mohan, Muhammad Qasim Mushtaq Warraich, Yvonne Kavanagh, Brendan Duffy, Edmond F. Tobin
Articles
Cavitation erosion and erosion-corrosion are the popular failure modes of hydronautics components namely propellers, valves, turbines etc which occurs due to mechanical destructions and electrochemical corrosion. Erosion corrosion is caused due to surge in the number of solid particles affecting the surfaces whereas cavitation erosion is caused due to steady collapse of cavities or bubbles. Aluminium alloys are widely used in marine renewable industries owing to its high strength, light weight and good corrosion resistance. Despite that, cavitation and erosion-corrosion are the limiting factors for these alloys. The aim of the present work is to produce a coating system capable …
Feature Papers In Optical Sensors 2022, Vittorio M. N. Passaro, Yuliya Semenova, Benjamin Miller
Feature Papers In Optical Sensors 2022, Vittorio M. N. Passaro, Yuliya Semenova, Benjamin Miller
Articles
Today, optical sensors are the subject of a very significant number of studies and applications. Many well-established technologies, including free-space optics, integrated photonics, and fiber optics approaches, have been developed in recent decades to fabricate and develop increasingly more efficient optical sensors for applications ranging from industrial control to monitoring the environment, biomedical use, and even as part of the Internet of Things.
Evaluation Of The Photon Contributions To The Solar Energy Conversion For Organic Luminescent Down-Shifting Liquid Beam Splitters In Hybrid Photovoltaic-Thermal (Pvt) Applications Using Raytracing Monte Carlo Simulations, Kenneth Coldrick
Articles
A hybrid photovoltaic-thermal (PVT) system combines photovoltaic (PV) and photo-thermal (PT) energy collection into a single structure, enhancing the potential to achieve greater solar energy conversion efficiencies. Such enhanced efficiencies can result in greater economic returns and could promote a larger uptake of PVT devices in cold and temperate climate countries. Through the utilization of a Monte Carlo ray-tracing model, this work provides new insights into the optical, electrical, and thermal characteristics of PVT devices. In particular, the work focuses on evaluating the behaviour of novel luminescent imidazole-phenanthroline-based working fluids that were previously experimentally investigated as liquid spectral beam splitters …
Color-Changing Reflection Hologram For Quality Assurance Of Therapeutic Ultrasound Systems, Tatsiana Mikulchyk, John Walsh, Jacinta Browne, Izabela Naydenova, Dervil Cody
Color-Changing Reflection Hologram For Quality Assurance Of Therapeutic Ultrasound Systems, Tatsiana Mikulchyk, John Walsh, Jacinta Browne, Izabela Naydenova, Dervil Cody
Articles
The acoustic output of clinical therapeutic ultrasound equipment requires regular quality assurance (QA) testing to ensure the safety and efficacy of the treatment and that any potentially harmful deviations from the expected output power density are detected as soon as possible. A hologram, consisting of a reflection grating fabricated in an acrylate photopolymer film, has been developed to produce an immediate, visible, and permanent change in the color of the reconstructed hologram from red to green in response to incident ultrasound energy. The influence of the therapeutic ultrasound insonation parameters (exposure time, ultrasound power density, and proximity to the point …
Review-Electrode Kinetics And Electrolyte Stability In Vanadium Flow Batteries, Andrea Bourke, Daniela Oboroceanu, Nathan Quill, Catherine Lenihan, Maria Alhajji Safi Maria Alhajji Safi, Mallory A. Miller, Robert F. Savinell, Jesse S. Wainright, Varsha Sasikumarsp, Maria Rybalchenko, Pupak Amini, Niall Dalton, Robert P. Lynch, D. Noel Buckley
Review-Electrode Kinetics And Electrolyte Stability In Vanadium Flow Batteries, Andrea Bourke, Daniela Oboroceanu, Nathan Quill, Catherine Lenihan, Maria Alhajji Safi Maria Alhajji Safi, Mallory A. Miller, Robert F. Savinell, Jesse S. Wainright, Varsha Sasikumarsp, Maria Rybalchenko, Pupak Amini, Niall Dalton, Robert P. Lynch, D. Noel Buckley
Articles
Two aspects of vanadium flow batteries are reviewed: electrochemical kinetics on carbon electrodes and positive electrolyte stability. There is poor agreement between reported values of kinetic parameters; however, most authors report that kinetic rates are faster for VIV/VV than for VII/VIII. Cycling the electrode potential increases the rates of both reactions initially due to roughening but when no further roughening is observed, the VII/VIII and VIV/VV reactions are affected oppositely by the pretreatment potential. Anodic pretreatment activates the electrode for the VII/VIII reaction, and deactivates it for VIV/VV. Three states of the carbon surface are suggested: reduced and oxidized states …
The Lagrangian Formulation For Wave Motion With A Shear Current And Surface Tension, Conor Curtin, Rossen Ivanov
The Lagrangian Formulation For Wave Motion With A Shear Current And Surface Tension, Conor Curtin, Rossen Ivanov
Articles
The Lagrangian formulation for the irrotational wave motion is straightforward and follows from a Lagrangian functional which is the difference between the kinetic and the potential energy of the system. In the case of fluid with constant vorticity, which arises for example when a shear current is present, the separation of the energy into kinetic and potential is not at all obvious and neither is the Lagrangian formulation of the problem. Nevertheless, we use the known Hamiltonian formulation of the problem in this case to obtain the Lagrangian density function, and utilising the Euler-Lagrange equations we proceed to derive some …
Improving The Angular Visibility Of Photopolymer-Based Reflection Holograms For Sensing Applications, Tatsiana Mikulchyk, Kevin Murphy, John Walsh, Suzanne Martin, Dervil Cody, Izabela Naydenova
Improving The Angular Visibility Of Photopolymer-Based Reflection Holograms For Sensing Applications, Tatsiana Mikulchyk, Kevin Murphy, John Walsh, Suzanne Martin, Dervil Cody, Izabela Naydenova
Articles
Volume reflection hologram-based sensors are designed to visibly change colour in response to a target stressor or analyte. However, reflection holograms fabricated in thick photopolymer films are highly angularly selective, making these sensors challenging to view and interpret by non-experts. Here, the use of speckle holography to improve the visibility of reflection holograms is presented. A novel recording approach combining speckle recording techniques with Denisyuk reflection recording geometry is described. The recorded speckle reflection grating operates as a series of multiplexed reflection gratings with a range of spatial frequencies, capable of reflecting light at a wider range of angles. A …