scholarly journals Interrelationship between Lab, Space, Astrophysical, Magnetic Fusion, and Inertial Fusion Plasma Experiments

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 35
Author(s):  
Mark Koepke
Keyword(s):  
Laboratory Experiments ◽  
Theoretical Models ◽  
Space Physics ◽  
Inertial Fusion ◽  
Magnetic Fusion ◽  
Fusion Plasma ◽  
Laboratory Plasma ◽  
Plasma Parameters ◽  
Wide Range ◽  
Laboratory Investigations

The objectives of this review are to articulate geospace, heliospheric, and astrophysical plasma physics issues that are addressable by laboratory experiments, to convey the wide range of laboratory experiments involved in this interdisciplinary alliance, and to illustrate how lab experiments on the centimeter or meter scale can develop, through the intermediary of a computer simulation, physically credible scaling of physical processes taking place in a distant part of the universe over enormous length scales. The space physics motivation of laboratory investigations and the scaling of laboratory plasma parameters to space plasma conditions, having expanded to magnetic fusion and inertial fusion experiments, are discussed. Examples demonstrating how laboratory experiments develop physical insight, validate or invalidate theoretical models, discover unexpected behavior, and establish observational signatures for the space community are presented. The various device configurations found in space-related laboratory investigations are outlined.

scholarly journals Onset of fast magnetic reconnection and particle energization in laboratory and space plasmas

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
F. Pucci ◽  
M. Velli ◽  
C. Shi ◽  
K. A. P. Singh ◽  
A. Tenerani ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Theoretical Models ◽  
Laboratory Plasma ◽  
Plasma Parameters ◽  
Astrophysical Plasmas ◽  
Plasma Dynamics ◽  
Laboratory Plasmas ◽  
Wide Range ◽  
Kinetic Effects

The onset of magnetic reconnection in space, astrophysical and laboratory plasmas is reviewed discussing results from theory, numerical simulations and observations. After a brief introduction on magnetic reconnection and approach to the question of onset, we first discuss recent theoretical models and numerical simulations, followed by observations of reconnection and its effects in space and astrophysical plasmas from satellites and ground-based detectors, as well as measurements of reconnection in laboratory plasma experiments. Mechanisms allowing reconnection spanning from collisional resistivity to kinetic effects as well as partial ionization are described, providing a description valid over a wide range of plasma parameters, and therefore applicable in principle to many different astrophysical and laboratory environments. Finally, we summarize the implications of reconnection onset physics for plasma dynamics throughout the Universe and illustrate how capturing the dynamics correctly is important to understanding particle acceleration. The goal of this review is to give a view on the present status of this topic and future interesting investigations, offering a unified approach.

Dynamics and Performance of a Harmonically Excited Vertical Impact Damper

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Sanjiv Ramachandran ◽  
George Lesieutre
Keyword(s):  
Loss Factor ◽  
Vertical Direction ◽  
Theoretical Models ◽  
Coefficient Of Restitution ◽  
Numerical Continuation ◽  
Particle Impact ◽  
Impact Damper ◽  
High Loss ◽  
Wide Range ◽  
And Performance

Particle impact dampers (PIDs) have been shown to be effective in vibration damping. However, our understanding of such dampers is still limited, based on the theoretical models existing today. Predicting the performance of the PID is an important problem, which needs to be investigated more thoroughly. This research seeks to understand the dynamics of a PID as well as those parameters which govern its behavior. The system investigated is a particle impact damper with a ceiling, under the influence of gravity. The base is harmonically excited in the vertical direction. A two-dimensional discrete map is obtained, wherein the variables at one impact uniquely dictate the variables at the next impact. This map is solved using a numerical continuation procedure. Periodic impact motions and “irregular” motions are observed. The effects of various parameters such as the gap clearance, coefficient of restitution, and the base acceleration are analyzed. The dependence of the effective damping loss factor on these parameters is also studied. The loss factor results indicate peak damping for certain combinations of parameters. These combinations of parameters correspond to a region in parameter space where two-impacts-per-cycle motions are observed over a wide range of nondimensional base accelerations. The value of the nondimensional acceleration at which the onset of two-impacts-per-cycle solutions occurs depends on the nondimensional gap clearance and the coefficient of restitution. The range of nondimensional gap clearances over which two-impacts-per-cycle solutions are observed increases as the coefficient of restitution increases. In the regime of two-impacts-per-cycle solutions, the value of nondimensional base acceleration corresponding to onset of these solutions initially decreases and then increases with increasing nondimensional gap clearance. As the two-impacts-per-cycle solutions are associated with high loss factors that are relatively insensitive to changing conditions, they are of great interest to the designer.

Mate availability facilitates cannibalistic behaviour in a nest brooding fish: effects of timing during the brood cycle

Behaviour ◽  
2011 ◽  
Vol 148 (2) ◽  
pp. 247-264 ◽  
Author(s):  
Masanori Kohda ◽  
Nobuhiro Ohnishi ◽  
Noboru Okuda ◽  
Tomohiro Takeyama ◽  
Omar Myint
Keyword(s):  
Laboratory Experiments ◽  
Gravid Female ◽  
Theoretical Models ◽  
Filial Cannibalism ◽  
Mate Availability ◽  
Stimulus Female ◽  
Trade Offs ◽  
Future Reproduction ◽  
Cannibalistic Behaviour ◽  
The Subject

AbstractFilial cannibalism, eating one's own viable offspring, is accepted as an adaptive response to trade-offs between current and future reproduction. Theoretical models predict that high mate availability may induce more filial cannibalism, but this prediction is rarely tested. To examine this prediction, we performed laboratory experiments using the nest breeding goby Rhinogobius flumineus. Subject males were allowed to mate with a gravid female and care for the broods. A separate gravid female housed in a small cage (stimulus-female) was shown to the subject males at one of three different points during the brood cycle: prior to spawning, within 1 day after spawning and 1 week after spawning. Empty cages were shown as a control. Males that were shown the stimulus-female before spawning cannibalised more eggs than control males. In contrast, males that were shown the stimulus-females after spawning cannibalised as few eggs as control males did. Additionally, males that were shown the stimulus-female prior to spawning did not court females more intensively than other males. Thus, we suggest that the presence of an additional mate, rather than energy expenditure associated with courtship directed toward an additional mate, can facilitate males to cannibalise their eggs.

Optimization of Growth Conditions of Citrus Anthracnose Agent Colletotrichum gloeosporioides Isolates in Tunisia

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Ben Hadj-Daoud H ◽  
◽  
Ben Salem I ◽  
Boughalleb-M’Hamdi N ◽  
◽  
...  
Keyword(s):  
Morphological Traits ◽  
Laboratory Experiments ◽  
Plant Pathogens ◽  
Colletotrichum Gloeosporioides ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Fruit Drop ◽  
Nutritional Conditions ◽  
Solid Media ◽  
Wide Range

Background: Colletotrichum gloeosporioides is important plant pathogens on a wide range of plant hosts such as citrus causing pre- or post-harvest infections as anthracnose, post-bloom fruit drop, tearstain and stem-end rot on fruit, or wither-tip of twigs. Method: The optimization of growth conditions of this pathogen was performed (solid media, temperature, pH and water potential under laboratory experiments). Results: Our results revealed that the maximum radial growth of C. gloeosporioides was recorded on SDA medium. All isolates were able to grow on PDA at temperatures of 15 and 30°C (over 0.7cm/day). Optimal growth radial was recorded at pH 5, 6, 7 and 8. Similar responses were obtained with both salt types, but, in general, C. gloeosporioides was more tolerant to KCl than NaCl. Conclusion: Studies of cultural, morphological traits of the pathogen are prominent to understand the response of the pathogen in different environmental and nutritional conditions.

Viscosity Effect on Thermocapillary Rupture of Falling Liquid Films

2010 ◽  
Author(s):  
Dmitry Zaitsev ◽  
Andrey Semenov ◽  
Oleg Kabov
Keyword(s):  
Heat Flux ◽  
Film Thickness ◽  
Inclination Angle ◽  
Theoretical Models ◽  
Liquid Films ◽  
Liquid Viscosity ◽  
Inclined Plate ◽  
Film Rupture ◽  
Generalize Data ◽  
Wide Range

Rupture of a subcooled liquid film flowing over an inclined plate with a 150×150 mm heater is studied for a wide range of liquid viscosity (dynamic viscosity μ = (0.91–17.2)x10−3 Pa·s) and plate inclination angle with respect to the horizon (Θ = 3–90 deg). The main governing parameters of the experiment and their respective values are: Reynolds number Re = 0.15–54, heat flux q = 0–224 W/cm2. The effect of the heat flux on the film flow leads to the formation of periodically flowing rivulets and thin film between them. As the heat flux grows the film thickness between rivulets gradually decreases, and, upon reaching a certain threshold heat flux, qidp, the film ruptures in the area between the rivulets. The threshold heat flux increases with the flow rate of liquid and with the liquid viscosity, while the plate inclination angle has little effect on qidp. Criterion Kp, which is traditionally used in the literature to predict thermocapillary film rupture, was found to poorly generalize data for high viscous liquids (ethylene glycol, and aqueous solutions of glycerol) and also data for Θ≤45 deg. The criterion Kp was modified by taking into account characteristic critical film thickness for film rupture under isothermal conditions (no heating), deduced from existing theoretical models. The modified criterion has allowed to successfully generalize data for whole ranges of μ, Re, Θ and q, studied.

scholarly journals Sustaining community-university partnerships

2011 ◽  
Vol 4 ◽  
pp. 1-11 ◽  
Author(s):  
Simon Northmore ◽  
Angie Hart
Keyword(s):  
Research Question ◽  
Theoretical Models ◽  
The United States ◽  
University Partnerships ◽  
Reciprocal Relationships ◽  
Mutual Learning ◽  
Community Needs ◽  
Wide Range ◽  
University Partnership

In recent years there has been a huge growth in the academic literature on community-university partnership working. However, much of this is practice based and the issue of how such partnerships can be sustained over time is not adequately reflected in the literature. This introductory chapter lays the foundations for the subsequent thirteen articles by first discussing notions of sustainability, in part by providing a brief overview of the Community University Partnership Programme (Cupp) at the University of Brighton, UK. After a period of rapid growth, we are increasingly concerned with how to sustain the reciprocal relationships that underpin long-term engagement, a situation exacerbated by potential looming funding cuts. Paradoxically, however, this article suggests that while funding is an important element of sustainability, the current economic challenges may help to generate sustainability as community-university partnerships are forced to examine what other factors contribute to lasting relationships. It is these ‘other factors’ that the articles in this collection fruitfully explore. Coming from the United States, the United Kingdom and Australia, they examine the core research question that concerns us: how do we address the challenges of building sustainable community-university partnerships, especially with disadvantaged and excluded communities, at a time of diminishing resources? Despite the wide range of community needs and methodological diversity involved, the articles suggest that some common characteristics underpin sustainability. These include: genuine reciprocity; mutual learning; and a creative approach to partnership building that recognises the diverse purposes of partners. This introductory chapter concludes that there is a need to further refine our understanding of community-university partnerships through the development of more theoretical models of sustainability. Keywords: sustainability, partnerships, reciprocal relationships, mutual learning

scholarly journals Multilayer modelling of waves generated by explosive submarine volcanism

2021 ◽  
Author(s):  
Matthew W. Hayward ◽  
Colin N. Whittaker ◽  
Emily M. Lane ◽  
William Power ◽  
Stéphane Popinet ◽  
...  
Keyword(s):  
Underwater Explosion ◽  
Theoretical Models ◽  
Mono Lake ◽  
Tsunami Source ◽  
Computationally Efficient ◽  
Relative Significance ◽  
Submarine Volcanism ◽  
Wave Characteristics ◽  
Wide Range ◽  
Source Models

Abstract. Theoretical source models of underwater explosions are often applied in studying tsunami hazards associated with submarine volcanism; however, their use in numerical codes based on the shallow water equations can neglect the significant dispersion of the generated wavefield. A non-hydrostatic multilayer method is validated against a laboratory-scale experiment of wave generation from instantaneous disturbances and at field-scale submarine explosions at Mono Lake, California, utilising the relevant theoretical models. The numerical method accurately reproduces the range of observed wave characteristics for positive disturbances and suggests a previously unreported relationship of extended initial troughs for negative disturbances at low dispersivity and high nonlinearity parameters. Satisfactory amplitudes and phase velocities within the initial wave group are found using underwater explosion models at Mono Lake. The scheme is then applied to modelling tsunamis generated by volcanic explosions at Lake Taupō, New Zealand, for a magnitude range representing ejecta volumes between 0.04–0.4 km3. Waves reach all shores within 15 minutes with maximum incident crest amplitudes around 4 m at shores near the source. This work shows that the multilayer scheme used is computationally efficient and able to capture a wide range of wave characteristics, including dispersive effects, which is necessary when investigating submarine explosions. This research therefore provides the foundation for future studies involving a rigorous probabilistic hazard assessment to quantify the risks and relative significance of this tsunami source mechanism.

scholarly journals SHEETFLOW SEDIMENT TRANSPORT UNDER SKEWED - ASYMMETRIC WAVES AND CURRENTS

2012 ◽  
Vol 1 (33) ◽  
pp. 50 ◽  
Author(s):  
Le Phuong Dong ◽  
Shinji Sato
Keyword(s):  
Sediment Transport ◽  
Laboratory Experiments ◽  
Fine Sand ◽  
Sand Transport ◽  
Phase Lag ◽  
Half Cycle ◽  
Experimental Conditions ◽  
Wide Range ◽  
Waves And Currents ◽  
Asymmetric Flows

Prototype scale laboratory experiments have been conducted to investigate the sheetflow sediment transport of uniform sands under different skewed-asymmetric oscillatory flows. Experimental results reveal that in most of the case with fine sand, the “cancelling effect”, which balances the on-/off-shore net transport under pure asymmetric/skewed flows and results a moderate net transport, was developed for combined skewed-asymmetric flow. However, under some certain conditions (T > 5s) with coarse sands, the onshore sediment transport was enhanced by 50% under combined skewed-asymmetric flows. Sand transport mechanism under oscillatory sheetflow conditions is also studied by comparing the maximum bed shear stress and the phase lag parameter at each half cycle. A comparison of measurements including the new experimental data with a number of practical sand transport formulations shows that the Dong et al. (2013) formulation performs the best in predicting the measured net transport rates over a wide range of experimental conditions

scholarly journals Reproduction of Semantic Content of Subjects, Predicates, and Objects and Its Dependence on the Use Of Attributes and Adverbial Modifiers in Sentence Composition

2021 ◽  
pp. 30-47
Author(s):  
Sergey V. Malanov ◽  
◽  
Marina S. Polyakova ◽  
Keyword(s):  
Theoretical Models ◽  
Semantic Content ◽  
Additional Research ◽  
Independent Variables ◽  
Wide Range ◽  
Dependent Variables ◽  
The Subject ◽  
Adverbial Modifiers

In the article describes the influence of syntactic organization of speech utterances on peculiarities of actualization and reproduction of their subject-semantic content (meanings). There has been tested the hypotheses that the semantic content of subjects, predicates, and objects is reproduced more efficiently: 1) when attributes are used in the composition of statements with nouns (subjects and objects), and with verbs (predicates) – adverbial modifiers; 2) when there is a deliberate focus on highlighting the semantic content of nouns or verbs in the composition of statements. The methods of varying lexical and syntactic means in the text composition presented to respondents were used as independent variables. The language means respondents used to manifest fragments of semantic content were analyzed as dependent variables. The study involved 90 respondents (72 men, 18 women) aged 25-40. While the first hypothesis has been confirmed, the second still requires additional research. The results obtained indicate that in updating and reproducing the subject-semantic content of speech utterances it is the attribution of signs and properties to objects and processes that is of great importance.The experimental organization scheme used in the study reveals a wide range of patterns that can serve to confirm / refute various hypotheses and theoretical models in psycholinguistics.

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