scholarly journals Effects of radiation pressure on the evaporative wind of HD 209458b

2020 ◽  
Vol 493 (1) ◽  
pp. 1292-1305 ◽  
Author(s):  
Alex Debrecht ◽  
Jonathan Carroll-Nellenback ◽  
Adam Frank ◽  
Eric G Blackman ◽  
Luca Fossati ◽  
...  
Keyword(s):  
Radiation Pressure ◽  
High Energy ◽  
Line Of Sight ◽  
Hydrodynamic Simulation ◽  
High Energy Radiation ◽  
Hydrodynamic Simulations ◽  
Cometary Tail ◽  
Effects Of Radiation ◽  
Simplified Calculation

ABSTRACT The role of radiation pressure in shaping exoplanet photoevaporation remains a topic of contention. Radiation pressure from the exoplanet’s host star has been proposed as a mechanism to drive the escaping atmosphere into a ‘cometary’ tail and explain the high velocities observed in systems where mass-loss is occurring. In this paper, we present results from high-resolution 3D hydrodynamic simulations of a planet similar to HD 209458b. We self-consistently launch a wind flowing outwards from the planet by calculating the ionization and heating resulting from incident high-energy radiation, and account for radiation pressure. We first present a simplified calculation, setting a limit on the Lyman-α flux required to drive the photoevaporated planetary material to larger radii and line-of-sight velocities. We then present the results of our simulations, which confirm the limits determined by our analytic calculation. We thus demonstrate that, within the limits of our hydrodynamic simulation and for the Lyman-α fluxes expected for HD 209458, radiation pressure is unlikely to significantly affect photoevaporative winds or to explain the high velocities at which wind material is observed, though further possibilities remain to be investigated.

scholarly journals EXTENDED PLANCK SCALE

2003 ◽  
Vol 18 (15) ◽  
pp. 1037-1042 ◽  
Author(s):  
F. I. COOPERSTOCK ◽  
V. FARAONI
Keyword(s):  
Z Boson ◽  
Mass Spectra ◽  
Planck Scale ◽  
Structure Constant ◽  
High Energy ◽  
Fine Structure Constant ◽  
High Energy Radiation ◽  
Planck Mass ◽  
Null Surface

Traditional derivations of the Planck mass ignore the role of charge and spin in general relativity. From the Kerr–Newman null surface and horizon radii, quantized charge and spin dependence are introduced in an extended Planck scale of mass. Spectra emerge with selection rules dependent upon the choice of Kerr–Newman radius to link with the Compton wavelength. The appearance of the fine structure constant suggests the possibility of a variation in time of the extended Planck mass, which may be much larger than the variation in the traditional one. There is a suggestion of a connection with the α value governing high-energy radiation in Z-boson production and decay.

scholarly journals The Role of Low-Energy Electron Interactions in cis-Pt(CO)2Br2 Fragmentation

2021 ◽  
Vol 22 (16) ◽  
pp. 8984
Author(s):  
Maicol Cipriani ◽  
Styrmir Svavarsson ◽  
Filipe Ferreira da Silva ◽  
Hang Lu ◽  
Lisa McElwee-White ◽  
...  
Keyword(s):  
Coordination Compound ◽  
Electron Attachment ◽  
High Energy ◽  
Low Energy ◽  
Carbonyl Complexes ◽  
Secondary Electrons ◽  
High Energy Radiation ◽  
Low Energy Electrons ◽  
In Cis

Platinum coordination complexes have found wide applications as chemotherapeutic anticancer drugs in synchronous combination with radiation (chemoradiation) as well as precursors in focused electron beam induced deposition (FEBID) for nano-scale fabrication. In both applications, low-energy electrons (LEE) play an important role with regard to the fragmentation pathways. In the former case, the high-energy radiation applied creates an abundance of reactive photo- and secondary electrons that determine the reaction paths of the respective radiation sensitizers. In the latter case, low-energy secondary electrons determine the deposition chemistry. In this contribution, we present a combined experimental and theoretical study on the role of LEE interactions in the fragmentation of the Pt(II) coordination compound cis-PtBr2(CO)2. We discuss our results in conjunction with the widely used cancer therapeutic Pt(II) coordination compound cis-Pt(NH3)2Cl2 (cisplatin) and the carbonyl analog Pt(CO)2Cl2, and we show that efficient CO loss through dissociative electron attachment dominates the reactivity of these carbonyl complexes with low-energy electrons, while halogen loss through DEA dominates the reactivity of cis-Pt(NH3)2Cl2.

scholarly journals Young planets under extreme UV irradiation

2018 ◽  
Vol 612 ◽  
pp. A25 ◽  
Author(s):  
D. Kubyshkina ◽  
M. Lendl ◽  
L. Fossati ◽  
P. E. Cubillos ◽  
H. Lammer ◽  
...  
Keyword(s):  
Equilibrium Temperature ◽  
High Energy ◽  
High Energy Radiation ◽  
Hydrodynamic Simulations ◽  
Planetary Evolution ◽  
Atmospheric Escape ◽  
Stellar Radiation ◽  
Extreme Uv ◽  
High Level ◽  
Increasing Temperature

The K2-33 planetary system hosts one transiting ~5 R⊕ planet orbiting the young M-type host star. The planet’s mass is still unknown, with an estimated upper limit of 5.4 MJ. The extreme youth of the system (<20 Myr) gives the unprecedented opportunity to study the earliest phases of planetary evolution, at a stage when the planet is exposed to an extremely high level of high-energy radiation emitted by the host star. We perform a series of 1D hydrodynamic simulations of the planet’s upper atmosphere considering a range of possible planetary masses, from 2 to 40 M⊕, and equilibrium temperatures, from 850 to 1300 K, to account for internal heating as a result of contraction. We obtain temperature profiles mostly controlled by the planet’s mass, while the equilibrium temperature has a secondary effect. For planetary masses below 7–10 M⊕, the atmosphere is subject to extremely high escape rates, driven by the planet’s weak gravity and high thermal energy, which increase with decreasing mass and/or increasing temperature. For higher masses, the escape is instead driven by the absorption of the high-energy stellar radiation. A rough comparison of the timescales for complete atmospheric escape and age of the system indicates that the planet is more massive than 10 M⊕.

Photo-degradation of monoazo dye blue 13 using advanced oxidation process

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Aqueous Solution ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
High Energy ◽  
Uv Exposure ◽  
H2o2 Concentration ◽  
Oxidizing Agent ◽  
Photo Degradation ◽  
High Energy Radiation ◽  
Uv Lamp

The high energy radiation overcome the bonding of solute in a solution and H2O2 acts as an oxidizing agent and generates a free radical in the solution which results in photo-degradation by converting the solute in to simple form and resultantly, colored substance under the effect of photo-degradation becomes colorless. The photo-degradation of monoazo dye Blue 13 in an aqueous solution was investigated using a laboratory scale UV lamp in the presence of H2O2 and for maximum degradation of dye, the independent parameter UV power, UV exposure time, pH and H2O2 concentration were optimized. It was found that neither UV in the presence of H2O2 is able to degrade Blue 13 under optimum condition. The results revealed that the use of both UV and H2O2 have pronounced effect on the discoloration of dyes which could be used for management of textile effluents contain waste dyes.

Fundamentality

2017 ◽  
Author(s):  
Richard Healey
Keyword(s):  
Quantum Theory ◽  
High Energy Physics ◽  
Physical Property ◽  
Natural World ◽  
High Energy ◽  
Quantum Field Theories ◽  
Fundamental Physics ◽  
The World ◽  
Energy Physics

The metaphor that fundamental physics is concerned to say what the natural world is like at the deepest level may be cashed out in terms of entities, properties, or laws. The role of quantum field theories in the Standard Model of high-energy physics suggests that fundamental entities, properties, and laws are to be sought in these theories. But the contextual ontology proposed in Chapter 12 would support no unified compositional structure for the world; a quantum state assignment specifies no physical property distribution sufficient even to determine all physical facts; and quantum theory posits no fundamental laws of time evolution, whether deterministic or stochastic. Quantum theory has made a revolutionary contribution to fundamental physics because its principles have permitted tremendous unification of science through the successful application of models constructed in conformity to them: but these models do not say what the world is like at the deepest level.

scholarly journals Challenges and Opportunities for CsPbBr3 Perovskites in Low- and High-Energy Radiation Detection

2021 ◽  
pp. 1290-1314
Author(s):  
Lotte Clinckemalie ◽  
Donato Valli ◽  
Maarten B. J. Roeffaers ◽  
Johan Hofkens ◽  
Bapi Pradhan ◽  
...  
Keyword(s):  
Radiation Detection ◽  
High Energy ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Challenges And Opportunities

scholarly journals Pannexins and Connexins: Their Relevance for Oocyte Developmental Competence

2021 ◽  
Vol 22 (11) ◽  
pp. 5918
Author(s):  
Paweł Kordowitzki ◽  
Gabriela Sokołowska ◽  
Marta Wasielak-Politowska ◽  
Agnieszka Skowronska ◽  
Mariusz T. Skowronski
Keyword(s):  
Assisted Reproductive Technologies ◽  
Mammalian Species ◽  
Atp Release ◽  
Reproductive Technologies ◽  
High Energy ◽  
Developmental Competence ◽  
Physiological Processes ◽  
Protein Group ◽  
Multicellular Organisms

The oocyte is the major determinant of embryo developmental competence in all mammalian species. Although fundamental advances have been generated in the field of reproductive medicine and assisted reproductive technologies in the past three decades, researchers and clinicians are still trying to elucidate molecular factors and pathways, which could be pivotal for the oocyte’s developmental competence. The cell-to-cell and cell-to-matrix communications are crucial not only for oocytes but also for multicellular organisms in general. This latter mentioned communication is among others possibly due to the Connexin and Pannexin families of large-pore forming channels. Pannexins belong to a protein group of ATP-release channels, therefore of high importance for the oocyte due to its requirements of high energy supply. An increasing body of studies on Pannexins provided evidence that these channels not only play a role during physiological processes of an oocyte but also during pathological circumstances which could lead to the development of diseases or infertility. Connexins are proteins that form membrane channels and gap-junctions, and more precisely, these proteins enable the exchange of some ions and molecules, and therefore they do play a fundamental role in the communication between the oocyte and accompanying cells. Herein, the role of Pannexins and Connexins for the processes of oogenesis, folliculogenesis, oocyte maturation and fertilization will be discussed and, at the end of this review, Pannexin and Connexin related pathologies and their impact on the developmental competence of oocytes will be provided.

scholarly journals Signatures of the Carrier Envelope Phase in Nonlinear Thomson Scattering

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 528
Author(s):  
Marcel Ruijter ◽  
Vittoria Petrillo ◽  
Thomas C. Teter ◽  
Maksim Valialshchikov ◽  
Sergey Rykovanov
Keyword(s):  
Laser Pulse ◽  
Radiation Spectrum ◽  
Thomson Scattering ◽  
High Energy ◽  
Phase Changes ◽  
High Energy Radiation ◽  
Carrier Envelope Phase ◽  
High Intensity Laser ◽  
Experimental Parameters ◽  
Intensity Laser

High-energy radiation can be generated by colliding a relativistic electron bunch with a high-intensity laser pulse—a process known as Thomson scattering. In the nonlinear regime the emitted radiation contains harmonics. For a laser pulse whose length is comparable to its wavelength, the carrier envelope phase changes the behavior of the motion of the electron and therefore the radiation spectrum. Here we show theoretically and numerically the dependency of the spectrum on the intensity of the laser and the carrier envelope phase. Additionally, we also discuss what experimental parameters are required to measure the effects for a beamed pulse.

scholarly journals POS1388 ULTRASOUND FOR PANNICULITIS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 977.1-977
Author(s):  
A. Potapova ◽  
O. Egorova ◽  
O. Alekseeva ◽  
A. Volkov ◽  
S. Radenska-Lopovok
Keyword(s):  
Dynamic Range ◽  
Subcutaneous Fat ◽  
Diagnostic Value ◽  
High Energy ◽  
Contralateral Side ◽  
Imaging Method ◽  
Non Invasive ◽  
M 12

Background:Ultrasound (US) is a non-invasive and safe imaging method that allows in vivo differentiation of the morphological structures of subcutaneous fat (SCF) tissue in in normal and pathology.Objectives:Reveal features of ultrasound changes in SCF in panniculitis (Pn).Methods:57 patients (f – 45, m - 12) aged 18 - 67 years with an initial diagnosis of erythema nodosum and a disease duration of 3.6 ± 1.4 years were examined. In addition to the general clinical examination, a computed tomography of the chest organs and a pathomorphological examination of a skin biopsy from the site of the node were performed. Ultrasound was performed on a MyLabTwice apparatus (ESAOTE, Italy) using a multi-frequency linear transducer (10-18 MHz) with the PD technique, the parameters of which were adapted for recording low-speed flows (PRF 300-600 Hz, low filter, dynamic range - 20-40 dB), the presence of vascularization was assessed not only in the affected area, but also on the contralateral side using high-energy Doppler.Results:33 patients were diagnosed with septal Pn (SPn), 24 - lobular Pn (LPn). In all cases, the diagnosis was verified by histological examination. Ultrasound made it possible to assess the thickness, echoicity and vascularization of the SCF. In 35 patients, significant thickening of the SCF was revealed (as compared to the contralateral side), of which in 14 cases with SPn, in 21 - with LPn. Significant diffuse thickening of the SCF with the contralateral side was observed in 18 patients, incl. in 12 (66%) patients with LPn. Limited thickening was more typical for SPn (73%). A significant increase in the echoicity of the SCF was noted in all forms of Pn. A “lobular” echo pattern with an anechogenic environment was observed in 25 patients, of which 18 (72%) had LPn. An increase in vascularization compared to the contralateral side was recorded in 30 cases (SPn-17, LPn-13).Conclusion:The obtained preliminary results indicate the important role of ultrasound in assessing the depth and prevalence of the inflammatory process at Pn. To clarify the diagnostic value of this method, further studies are needed on a larger sample of patients.Disclosure of Interests:None declared

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