Introduction

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Physical Mechanism ◽  
Thermal Ecology ◽  
Evolutionary Processes ◽  
Physical Mechanisms ◽  
The Subject

This introduces the subject, laying out the organisation of the book and emphasising the importance of both simple underlying physical mechanisms and evolutionary variability to thermal ecology. It distinguishes physical mechanism from statistical description, and the importance of evolutionary processes in comparisons across species.

scholarly journals Sting Jets in Simulations of a Real Cyclone by Two Mesoscale Models

2010 ◽  
Vol 138 (11) ◽  
pp. 4054-4075 ◽  
Author(s):  
Oscar Martínez-Alvarado ◽  
Florian Weidle ◽  
Suzanne L. Gray
Keyword(s):  
Small Scale ◽  
Extratropical Cyclones ◽  
Vertical Resolution ◽  
Mesoscale Models ◽  
Physical Mechanisms ◽  
The United Kingdom ◽  
Scale Modeling ◽  
Surface Measurements ◽  
The Subject ◽  
Comparison Of The Results

Abstract The existence of sting jets as a potential source of damaging surface winds during the passage of extratropical cyclones has recently been recognized. However, there are still very few published studies on the subject. Furthermore, although it is known that other models are capable of reproducing sting jets, in the published literature only one numerical model [the Met Office Unified Model (MetUM)] has been used to numerically analyze these phenomena. This article aims to improve our understanding of the processes that contribute to the development of sting jets and show that model differences affect the evolution of modeled sting jets. A sting jet event during the passage of a cyclone over the United Kingdom on 26 February 2002 has been simulated using two mesoscale models, namely the MetUM and the Consortium for Small Scale Modeling (COSMO) model, to compare their performance. Given the known critical importance of vertical resolution in the simulation of sting jets, the vertical resolution of both models has been enhanced with respect to their operational versions. Both simulations have been verified against surface measurements of maximum gusts, satellite imagery, and Met Office operational synoptic analyses, as well as operational analyses from the ECMWF. It is shown that both models are capable of reproducing sting jets with similar, though not identical, features. Through the comparison of the results from these two models, the relevance of physical mechanisms, such as evaporative cooling and the release of conditional symmetric instability, in the generation and evolution of sting jets is also discussed.

Evolution and Scientific Theories of Changeability

2010 ◽  
Vol 22 (1) ◽  
pp. 115-133
Author(s):  
Boguslawa Lewandowska ◽  
Keyword(s):  
Research Methods ◽  
Natural Sciences ◽  
Synthetic Theory ◽  
Scientific Theories ◽  
Evolutionary Processes ◽  
Significant Group ◽  
Theory Of Evolution ◽  
Scientific Cognition ◽  
The Subject ◽  
Determinism And Indeterminism

Evolutionary processes are conditioned both by unique phenomena and probabilistic ones. Given probabilistic factors, one may speak of changeability of evolution. This essay attempts to model evolutionary processes by modeling changeability in the natural sciences. Yet a framework of determinism and indeterminism appears inadequate to apprehend evolutionary processes. Autodeterminism is a more promising framework for addressing the causal, functional, and probabilistic dimension of evolution. Such an approach ensures the possibility of perceiving and presenting the complexity of evolution. The essay proposes that the synthetic theory of evolution conjoins factors of evolution, determinism, and changeability. The question still remains whether one can say that real being, which exists in the stream of time, is the subject of philosophy. This puzzle may be resdved by showing that besides the scientific cognition of nature, there is another possible cognition--the philosophical cognition. This is reflected in a significant group of problems of philosophical cosmology which are not addressed by the natural sciences due to their research methods.

Physical Mechanisms of Thermal Transport in Nanofluids

2011 ◽  
Author(s):  
John Shelton ◽  
Frank Pyrtle
Keyword(s):  
Thermal Conductivity ◽  
Thermal Energy ◽  
Energy Exchange ◽  
System Analysis ◽  
Energy Transport ◽  
Physical Mechanism ◽  
Conductivity Enhancement ◽  
Physical Mechanisms ◽  
Dynamics Simulations ◽  
Thermal Energy Transport

Using molecular dynamics simulations, an analysis of the thermal conductivity enhancement of a copper/argon nanofluid is performed. First, verification of an increase of as much as ∼30% in the thermal conductivity of the theoretical nanofluid over the corresponding base fluid, due to increasing nanoparticle concentration, is presented. Thermal energy transport is then decomposed into potential, kinetic, and virial components, based on the Green-Kubo autocorrelation function used to calculate thermal conductivity from the microscopic properties of the system. Analysis of these components showed that as the concentration of the nanoparticle increases, the energy transported through the system, due to collisions within the fluid, decreases by as much as 80%. Additionally, the nanofluid system increasingly displays characteristics of an amorphous-like material with increasing concentration. The decrease in energy exchange, due to collisions, suggests another physical mechanism is present for thermal energy transport. Therefore, it is proposed that thermal diffusion is the physical mechanism that more significantly affects thermal energy transport within a nanofluid than had been previously suggested.

Principles of Thermal Ecology: Temperature, Energy, and Life

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Physical Environment ◽  
Fossil Record ◽  
Final Section ◽  
Thermal Ecology ◽  
Complex Relationship ◽  
Physical Mechanisms ◽  
Influence Of Temperature On ◽  
Rigorous Framework ◽  
Effects Of Temperature ◽  
The Relationship

Temperature affects everything. It influences all aspects of the physical environment and governs any process that involves a flow of energy, setting boundaries on what an organism can or cannot do. This novel textbook explores the key principles behind the complex relationship between organisms and temperature, namely the science of thermal ecology. It starts providing a rigorous framework for understanding the nature of temperature and the flow of energy in and out of the organism, before describing the influence of temperature on what organisms can do, and how fast they can do it. Central to this is the relationship between temperature and metabolism, which then forms the basis for an exploration of the effects of temperature on growth and size. Two chapters cover first endothermy (including how this expensive lifestyle might have evolved), and then when and how this is suspended in torpor and hibernation. With these fundamental principles covered, the book’s final section explores thermal ecology itself, incorporating the important extra dimension of interactions with other organisms. After an examination of the relationship between temperature, energy and diversity, an entire chapter is devoted to the crucially important subject of the nature of climate change and how organisms are responding to this. Throughout the book, emphasis is placed on the need for an understanding of the underlying physical mechanisms, and the important insights that can be gained from the historical and fossil record.

scholarly journals The heterogeneous nucleation of threading dislocations on partial dislocations in III-nitride epilayers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
J. Smalc-Koziorοwska ◽  
J. Moneta ◽  
P. Chatzopoulou ◽  
I. G. Vasileiadis ◽  
C. Bazioti ◽  
...  
Keyword(s):  
Heterogeneous Nucleation ◽  
Physical Mechanism ◽  
Dislocation Nucleation ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Physical Mechanisms ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Device Applications ◽  
Very High

Abstract III-nitride compound semiconductors are breakthrough materials regarding device applications. However, their heterostructures suffer from very high threading dislocation (TD) densities that impair several aspects of their performance. The physical mechanisms leading to TD nucleation in these materials are still not fully elucidated. An overlooked but apparently important mechanism is their heterogeneous nucleation on domains of basal stacking faults (BSFs). Based on experimental observations by transmission electron microscopy, we present a concise model of this phenomenon occurring in III-nitride alloy heterostructures. Such domains comprise overlapping intrinsic I1 BSFs with parallel translation vectors. Overlapping of two BSFs annihilates most of the local elastic strain of their delimiting partial dislocations. What remains combines to yield partial dislocations that are always of screw character. As a result, TD nucleation becomes geometrically necessary, as well as energetically favorable, due to the coexistence of crystallographically equivalent prismatic facets surrounding the BSF domain. The presented model explains all observed BSF domain morphologies, and constitutes a physical mechanism that provides insight regarding dislocation nucleation in wurtzite-structured alloy epilayers.

scholarly journals Magnetic white dwarfs: Observations, theory and future prospects

2016 ◽  
Vol 25 (01) ◽  
pp. 1630005 ◽  
Author(s):  
Enrique García–Berro ◽  
Mukremin Kilic ◽  
Souza Oliveira Kepler
Keyword(s):  
Magnetic Fields ◽  
White Dwarfs ◽  
Current Status ◽  
Future Prospects ◽  
Physical Mechanisms ◽  
Weak Magnetic Fields ◽  
Interesting Class ◽  
The Subject ◽  
Points Of View ◽  
The Magnetic Field

Isolated magnetic white dwarfs have field strengths ranging from [Formula: see text][Formula: see text]G to [Formula: see text][Formula: see text]G, and constitute an interesting class of objects. The origin of the magnetic field is still the subject of a hot debate. Whether these fields are fossil, hence the remnants of original weak magnetic fields amplified during the course of the evolution of the progenitor of white dwarfs, or on the contrary, are the result of binary interactions or, finally, other physical mechanisms that could produce such large magnetic fields during the evolution of the white dwarf itself, remains to be elucidated. In this work, we review the current status and paradigms of magnetic fields in white dwarfs, from both the theoretical and observational points of view.

scholarly journals The Impact of Nanofluids on Droplet/Spray Cooling of a Heated Surface: A Critical Review

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 80
Author(s):  
Yunus Tansu Aksoy ◽  
Yanshen Zhu ◽  
Pinar Eneren ◽  
Erin Koos ◽  
Maria Rosaria Vetrano
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heated Surface ◽  
Spray Cooling ◽  
Heat Transfer Process ◽  
Transfer Enhancement ◽  
Physical Mechanisms ◽  
The Subject ◽  
The Impact ◽  
Droplet Spray

Cooling by impinging droplets has been the subject of several studies for decades and still is, and, in the last few years, the potential heat transfer enhancement obtained thanks to nanofluids’ use has received increased interest. Indeed, the use of high thermal conductivity fluids, such as nanofluids’, is considered today as a possible way to strongly enhance this heat transfer process. This enhancement is related to several physical mechanisms. It is linked to the nanofluids’ rheology, their degree of stabilization, and how the presence of the nanoparticles impact the droplet/substrate dynamics. Although there are several articles on droplet impact dynamics and nanofluid heat transfer enhancement, there is a lack of review studies that couple these two topics. As such, this review aims to provide an analysis of the available literature dedicated to the dynamics between a single nanofluid droplet and a hot substrate, and the consequent enhancement or reduction of heat transfer. Finally, we also conduct a review of the available publications on nanofluids spray cooling. Although using nanofluids in spray cooling may seem a promising option, the few works present in the literature are not yet conclusive, and the mechanism of enhancement needs to be clarified.

Ideas for Creating a Stimulating Undergraduate Paleobiology Course: Emphasis on Student-Directed Learning, Evolution, and the Chronological Succession of Phanerozoic Life

2012 ◽  
Vol 12 ◽  
pp. 11-20
Author(s):  
David Sunderlin
Keyword(s):  
Learning Outcomes ◽  
Scientific Inquiry ◽  
Life Science ◽  
Course Design ◽  
Individual Interest ◽  
Design Strategies ◽  
Evolutionary Processes ◽  
Skill Sets ◽  
Directed Learning ◽  
The Subject

It is commonly noted that students with no prior coursework in paleobiology are intrigued with it. Whatever the reason, many students look forward to an undergraduate course in the subject, even if they are not earth or life science majors. We, as instructors, can seize on this interest and build on it with careful course design. Here I describe a deliberate pedagogical approach in my undergraduate paleobiology course using repeated student-directed learning (SDL) activities. I also detail two course design strategies that I have found to be particularly successful: 1) placing uncommonly heavy emphasis on evolutionary processes, and 2) studying fossil groups according to their general chronological succession through the Phanerozoic. Specifically, SDL in this course involves a suite of activities that the students have some role in designing, such as choosing the study organism for an analysis or developing hypotheses for testing with data collected from the field. SDL activities are integrated into each course module, helping to create a learning environment of scientific inquiry that balances prescribed readings and lecture components with individual, interest-driven research investigations into captivating aspects of the discipline. The course design highlights evolutionary processes early in the term, then follows an unorthodox, chronological approach to organismal paleobiology in the course's second half. The strategies described here have met with success over many course iterations, both in terms of student evaluations of their own learning and in assessment of how students reach learning outcomes regarding the acquisition of knowledge and scientific research skill-sets.

scholarly journals Low-Latitude Atmosphere-Ionosphere Effects Initiated by Strong Earthquakes Preparation Process

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Sergey Pulinets
Keyword(s):  
Physical Mechanism ◽  
Vertical Projection ◽  
Equatorial Anomaly ◽  
Low Latitude ◽  
Strong Earthquakes ◽  
Physical Mechanisms ◽  
Longitudinal Asymmetry ◽  
The Earth ◽  
Magnetic Conjugacy

Ionospheric and atmospheric anomalies registered around the time of strong earthquakes in low-latitude regions are reported now regularly. Majority of these reports have the character of case studies without clear physical mechanism proposed. Here we try to present the general conception of low-latitude effects using the results of the recent author’s publications, including also rethinking the earlier results interpreted basing on recently established background physical mechanisms of anomalies generation. It should be underlined that only processes initiated by earthquake preparation are considered. Segregation of low-latitude regions for special consideration is connected with the important role of ionospheric equatorial anomaly in the seismoionospheric coupling and specific character of low-latitude earthquake initiated effects. Three main specific features can be marked in low-latitude ionospheric anomalies manifestation: the presence of magnetic conjugacy in majority of cases, local longitudinal asymmetry of effects observed in ionosphere in relation to the vertical projection of epicenter onto ionosphere, and equatorial anomaly reaction even on earthquakes outside equatorial anomaly (i.e., 30–40 LAT). The equality of effects morphology regardless they observed over land or over sea implies only one possible explanation that these anomalies are initiated by gaseous emanations from the Earth crust, and radon plays the major role.

Current understanding of mesospheric transport processes

1987 ◽  
Vol 323 (1575) ◽  
pp. 655-666 ◽  
Keyword(s):  
Gravity Waves ◽  
Chemical Constituents ◽  
Transport Processes ◽  
Small Scale ◽  
Dynamical Structure ◽  
Strongly Coupled ◽  
Physical Mechanisms ◽  
Waves And Tides ◽  
The Subject ◽  
And Diffusion

The chemistry and transport processes taking place in the mesosphere (approximately 50—85 km altitude) are strongly coupled. In recent years, the physical mechanisms influencing the transport processes of the mesosphere have become better understood, through both theoretical and observational studies. Perhaps most importantly, a theoretical framework for describing the momentum deposition and diffusion due to breaking small-scale gravity waves has been developed and shown to result in thermal, chemical and dynamical structure that closely resembles observations. The transport due to planetary waves and tides has also been the subject of study. In this paper, the transport processes influencing mesospheric distributions of chemical constituents are briefly reviewed.

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