Controlled photo-discharge of dust in a complex plasma

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Michael McKinlay ◽  
Edward Thomas
Keyword(s):  
High Intensity ◽  
Dusty Plasmas ◽  
Lanthanum Hexaboride ◽  
Magnetized Plasma ◽  
Background Plasma ◽  
Proof Of Concept ◽  
Langmuir Probes ◽  
Complex Plasma ◽  
Dust Charge ◽  
Selection Of

One of the limitations in studying dusty plasmas is that many of the important properties of the dust (like the charge) are directly coupled to the surrounding plasma conditions rather than being determined independently. The application of high-intensity ultraviolet (UV) sources to generate discharging photoelectric currents may provide an avenue for developing methods of controlling dust charge. Careful selection of the parameters of the UV source and dust material may even allow for this to be accomplished with minimal perturbation of the background plasma. The Auburn Magnetized Plasma Research Laboratory (MPRL) has developed a ‘proof-of-concept’ experiment for this controlled photo-discharging of dust; a high-intensity, near-UV source was used to produce large changes in the equilibrium positions of lanthanum hexaboride ( $\textrm {LaB}_6$ ) particles suspended in an argon DC glow discharge with negligible changes in the potential, density and temperature profiles of the background plasma. The shifts in equilibrium position of the dust are consistent with a reduction in dust charge. Video analysis is used to quantify the changes in position, velocity and acceleration of a test particle under the influence of the UV and Langmuir probes are used to measure the effects on the plasma.

Effects of charge dispersion in dusty plasmas

1995 ◽  
Vol 54 (3) ◽  
pp. 373-391 ◽  
Author(s):  
T. K. Aslaksen
Keyword(s):  
Charge Distribution ◽  
Dusty Plasmas ◽  
Dust Particles ◽  
Dust Charge ◽  
Kinetic Effects ◽  
Current Equation

We investigate the charge-dispersive effects on a sheath of monosized dust particles in equilibrium. This is done through describing the dust particles by using equations in (x, v) space (kinetic space) that include terms originating from the charge distribution of the dust particles. The charge-dispersive terms are assumed to be completely determined by the local charging processes. We find that the effects due to these terms are opposed by the ordinary gradient terms in the current equation in kinetic space, and they are therefore smaller than first expected. We also identify kinetic effects that are not included in the usual expression for the dust charge in hydrodynamic space.

QualViz: a tool for visual representation of water quality models

2011 ◽  
Vol 63 (1) ◽  
pp. 171-177
Author(s):  
G. T. Parker
Keyword(s):  
Water Quality ◽  
Conceptual Models ◽  
Dynamic Behaviour ◽  
Specific Model ◽  
Model Complexity ◽  
Proof Of Concept ◽  
Quality Models ◽  
Biochemical Kinetics ◽  
Water Quality Models ◽  
Selection Of

As water quality models and their implementation have become increasingly diverse, complex and proprietary, a need for more thorough understanding of the differences between each alternative arises. The work presented here proposes a novel visualization paradigm for water quality applications which can be used to understand difference between implementations of identical and different conceptual models. A proof-of-concept visualization tool was developed and tested again three scenarios for four different conceptual models of biochemical kinetics. Results show representative figures illustrating how the approach can communicate differences in model complexity and dynamic behaviour. The proposed tool should help ensure more suitable application of water quality models in varied contexts. A discussion of quantifying model complexity in a single metric is also presented, and recommendations are made on the selection of various representational forms for communicating and exploring specific model characteristics.

Resonant electromagnetic wave mixing in a dusty plasma

1996 ◽  
Vol 55 (3) ◽  
pp. 349-358 ◽  
Author(s):  
Jin-Xiu Ma ◽  
M. Y. Yu ◽  
P. K. Shukla
Keyword(s):  
Acoustic Waves ◽  
Electromagnetic Waves ◽  
Phase Conjugation ◽  
Four Wave Mixing ◽  
Dusty Plasmas ◽  
Wave Mixing ◽  
Ion Acoustic Waves ◽  
Charge Fluctuations ◽  
Dust Charge ◽  
Dust Charge Fluctuations

Wave mixing resulting from the resonance of electromagnetic waves with ion acoustic waves modified by dust charge fluctuations is investigated. The corresponding nonlinear susceptibilities are derived and applied to the study of phase conjugation by four-wave mixing. It is shown that dust charge fluctuations can lead to a filling-up of the resonance-induced splitting of the phase-conjugate reflectivity, making the latter a useful tool for the diagnostics of dusty plasmas.

Selection of Single Harmonic Emission Peak for Producing Isolated Attosecond Pulse via Chirped-UV Combined Field

2019 ◽  
Vol 75 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Hang Liu ◽  
Li-Qiang Feng
Keyword(s):  
High Intensity ◽  
Laser Field ◽  
Laser Intensity ◽  
Potential Method ◽  
Emission Peak ◽  
Harmonic Emission ◽  
Low Intensity ◽  
Isolated Attosecond Pulse ◽  
Intensity Laser ◽  
Selection Of

AbstractA potential method to produce isolated attosecond pulses (IAPs) by using low-intensity chirped-UV combined field has been investigated. The results can be separated into three parts. First, by properly introducing the mid-chirp or down-chirp of the low-intensity laser field, the harmonic cutoff can be extended and achieve the referenced value, which is produced from the high-intensity referenced field. Moreover, the spectral continuum is contributed by a single harmonic emission peak, which is beneficial to produce IAPs. However, the harmonic yield is very low due to the lower driven laser intensity. Second, by properly adding a UV pulse, the harmonic yield can be enhanced and achieve the referenced value due to the UV resonance ionisation. The intensity of the combined field is lower than that of the referenced field, which reduces the experimental requirements for producing high-intensity spectral continuum. Third, with the introduction of the positive or negative inhomogeneous effect of the mid-chirped combined field or down-chirped combined field, respectively, the similar harmonic cutoff and harmonic yield can also be obtained but with a much lower driven laser intensity. Finally, by superposing the harmonics on the spectral continuum, the IAPs with the durations of sub-38 as can be obtained.

scholarly journals Comparative study of dust acoustic solitons in two-temperature ion homogeneous and inhomogeneous plasmas

2020 ◽  
Vol 14 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Rashmi Srivastava ◽  
Hitendra K. Malik ◽  
Devi Singh
Keyword(s):  
Solitary Waves ◽  
Inhomogeneous Plasma ◽  
Low Frequency ◽  
Soliton Solutions ◽  
Dusty Plasmas ◽  
Number Density ◽  
Dust Charge ◽  
Plasma Species ◽  
Dust Acoustic ◽  
Two Temperature

AbstractThe dust acoustic solitary waves are theoretically investigated in dusty plasmas for different cases of with and without density gradients. These low-frequency solitary waves are studied using appropriate Korteweg–de Vries equations obtained using relevant stretched coordinates. The soliton solutions in homogeneous plasma, weakly inhomogeneous plasma and strongly inhomogeneous plasma, are thoroughly investigated for studying the effect of different parameters like dust charge and density of all the plasma species on the soliton profiles. The combination of the dust charge with its number density changes the dynamics of the solitons and that is further affected by the number density of the hot ion with respect to the cold ions.

Proof of Concept of an Endoscopic Sutureless Valve Sizer

2016 ◽  
Vol 11 (5) ◽  
pp. 337-341 ◽  
Author(s):  
Marco Vola ◽  
Juan Pablo Maureira ◽  
Vito Giovanni Ruggieri ◽  
Jean-François Fuzellier ◽  
Salvatore Campisi ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Early Stage ◽  
Ascending Aorta ◽  
Aortic Annulus ◽  
Laboratory Evaluation ◽  
Proof Of Concept ◽  
Valve Size ◽  
Sutureless Valve ◽  
Selection Of

Objective In this paper, we present an endoscopic expandable sizer conceived to allow thoracoscopic aortic valve replacement with a sutureless prosthesis using a dynamic sizing of the aortic annulus. Methods Ten aortic torsos were prepared using a five-trocar thoracoscopic setting. Once the aortotomy was performed and the aortic valve leaflets removed, the technical feasibility of the endoscopic sizing (introduction into the trocar, expansion into the aortic annulus, determination of the valve size, and retraction) with the device was assessed. In case of successful thoracoscopic sizing, endoscopic implantation of a sutureless valve (five LivaNova Perceval prosthesis and five Medtronic 3f Enable bioprosthesis) was performed. Before ascending aorta closure, we assessed the appropriate sealing of the bioprosthesis in the native annulus with camera visualization and a nerve hook inspection. Results All the 10 endoscopic sizings were technically feasible. The scheduled aortic sutureless valve implantations were successfully performed. In all cases, fitting and placement of the sutureless bio-prosthesis in the flaccid heart was satisfactory, with no paraprosthetic leakage detectable by the nerve hook. Conclusions The use of the endoscopic expandable sizer is technically possible. In this early-stage test in the flaccid heart, selection of the valve size was satisfactory during thoracoscopic sutureless aortic bioprosthesis implantation. Further laboratory evaluation with fluid dynamics (aortic root pressurization) will be performed before a clinical study is started.

A Knowledge-Based Tool for the Selection of Design Options During the Competitive Tendering of Vehicle Systems

Volume 3 ◽  
2004 ◽  
Author(s):  
Clive I. Kerr ◽  
Rajkumar Roy ◽  
Peter J. Sackett
Keyword(s):  
Automotive Industry ◽  
Proof Of Concept ◽  
Competitive Tendering ◽  
Knowledge Based ◽  
Vehicle System ◽  
Tier 1 ◽  
Vehicle Systems ◽  
Design Options ◽  
Selection Of

In the automotive industry the activities of documenting the design options and generating the necessary request for quotations, for Tier 1 system suppliers to be awarded contracts for design and development, is complex and time-consuming since these activities are predominately manual and paper-based. Thus, a knowledge-based tool is being developed to aid the selection of the design options for vehicle systems during competitive tendering. The tool is based on ontologies in order to provide a common and shared definition for the options available for a given vehicle system. An overview of this approach is provided and, as a ‘proof of concept’, a case study involving seating systems is presented. This paper shows, through the seating system case study, how the functionalities and features of a vehicle system can be selected and documented in order to streamline the business process of contracting out product development through the supply chain.

scholarly journals High INtensity Interval Training In pATiEnts with intermittent claudication (INITIATE): protocol for a multicentre, proof-of-concept, prospective interventional study

BMJ Open ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. e038825
Author(s):  
Sean Pymer ◽  
Amy Harwood ◽  
Said Ibeggazene ◽  
Gordon McGregor ◽  
Chao Huang ◽  
...  
Keyword(s):  
Intermittent Claudication ◽  
High Intensity ◽  
Interval Training ◽  
Walking Distance ◽  
Peak Power Output ◽  
Service Research ◽  
Proof Of Concept ◽  
High Intensity Interval Training ◽  
Supervised Exercise ◽  
High Intensity Interval

IntroductionThe first-line recommended treatment for patients with intermittent claudication (IC) is a supervised exercise programme (SEP), which includes a minimum of 2-hours of exercise per week over a 12-week period. However, provision, uptake and adherence rates for these SEP programmes are poor, with time constraints cited as a common participant barrier. High-intensity interval training (HIIT) is more time-efficient and therefore has the potential to overcome this barrier. However, evidence is lacking for the role of HIIT in those with IC. This proof-of-concept study aims to consider the safety, feasibility, tolerability and acceptability of a HIIT programme for patients with IC.Methods and analysisThis multicentre, single-group, prospective, interventional feasibility study will recruit 40 patients with IC, who will complete 6 weeks of HIIT, 3 times a week. HIIT will involve a supervised programme of 10×1 min high-intensity cycling intervals at 85%–90% peak power output (PPO), interspaced with 10×1 min low intensity intervals at 20%–25% PPO. PPO will be determined from a baseline cardiopulmonary exercise test (CPET) and it is intended that patients will achieve ≥85% of maximum heart rate from CPET, by the end of the second HIIT interval. Primary outcome measures are safety (occurrence of adverse events directly related to the study), programme feasibility (including participant eligibility, recruitment and completion rates) and HIIT tolerability (ability to achieve and maintain the required intensity). Secondary outcomes include patient acceptability, walking distance, CPET cardiorespiratory fitness measures and quality of life outcomes.Ethics and disseminationEthical approval was obtained via a local National Health Service research ethics committee (Bradford Leeds – 18/YH/0112) and recruitment began in August 2019 and will be completed in October 2020. Results will be published in peer-reviewed journals and presented at international conferences and are expected to inform a future pilot randomised controlled trial of HIIT versus usual-care SEPs.Trial registration numberNCT04042311; Pre-results.

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