See
My website http://www.iact.csic.es/personal/julyan_cartwright
My Google scholar page http://scholar.google.com/citations?user=V78-fnAAAAAJ
and my Arxiv page http://arxiv.org/a/cartwright_j_1
for more information
Chemical gardens are biomimetic plantlike growths formed by a mixture of salts which precipitate ... more Chemical gardens are biomimetic plantlike growths formed by a mixture of salts which precipitate by a combination of the fluid dynamics of convection forced by osmosis, free convection and chemical reactions. Chemical gardens may be implicated in other phenomena which involve precipitation across a colloidal gel membrane that separates two different aqueous solutions, for example, in the context of geophysical pattern formation in geothermal vents, as well as in cement technology and metal corrosion processes. ...
Philosophical Transactions of the Royal Society B: Biological Sciences, 2019
How is sensing carried out by cilia in the mouse node, zebrafish Kupffer's vesicle and simila... more How is sensing carried out by cilia in the mouse node, zebrafish Kupffer's vesicle and similar left–right (LR) organizer organs in other species? Two possibilities have been put forward. In the former, cilia would detect some chemical species in the fluid; in the latter, they would detect fluid flow. In either case, the hypothesis is that an imbalance would be detected between this signalling coming from cilia on the left and right sides of the organizer, which would initiate a cascade of signals leading ultimately to the breaking of LR symmetry in the developing body plan of the organism. We review the evidence for both hypotheses. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’.
We derive from kinetic theory, fluid mechanics and thermodynamics the minimal continuum-level equ... more We derive from kinetic theory, fluid mechanics and thermodynamics the minimal continuum-level equations governing the flow of a binary, non-electrolytic mixture in an isotropic porous medium with osmotic effects. For dilute mixtures, these equations are linear and in this limit provide a theoretical basis for the widely used semi-empirical relations of Kedem & Katchalsky (Kedem & Katchalsky 1958 Biochim. Biophys. Acta 27, 229–246 (doi:10.1016/0006-3002(58)90330-5)), which have hitherto been validated experimentally but not theoretically. The above linearity between the fluxes and the driving forces breaks down for concentrated or non-ideal mixtures, for which our equations go beyond the Kedem–Katchalsky formulation. We show that the heretofore empirical solute permeability coefficient reflects the momentum transfer between the solute molecules that are rejected at a pore entrance and the solvent molecules entering the pore space; it can be related to the inefficiency of a Maxwellian...
Self-organizing precipitation processes, such as chemical gardens forming biomimetic micro- and n... more Self-organizing precipitation processes, such as chemical gardens forming biomimetic micro- and nanotubular forms, have the potential to show us new fundamental science to explore, quantify, and understand nonequilibrium physicochemical systems, and shed light on the conditions for life's emergence. The physics and chemistry of these phenomena, due to the assembly of material architectures under a flux of ions, and their exploitation in applications, have recently been termed chemobrionics. Advances in understanding in this area require a combination of expertise in physics, chemistry, mathematical modeling, biology, and nanoengineering, as well as in complex systems and nonlinear and materials sciences, giving rise to this new synergistic discipline of chemobrionics.
Chemical gardens and clock reactions are two of the best-known demonstration reactions in chemist... more Chemical gardens and clock reactions are two of the best-known demonstration reactions in chemistry. Until now these have been separate categories. We have discovered that a chemical garden confined to two dimensions is a clock reaction involving a phase change, so that after a reproducible and controllable induction period it explodes.
Proceedings of the Royal Society B: Biological Sciences, 2016
The degree to which biological control is exercised compared to physical control of the organizat... more The degree to which biological control is exercised compared to physical control of the organization of biogenic materials is a central theme in biomineralization. We show that the outlines of biogenic calcite domains with organic membranes are always of simple geometries, while without they are much more complex. Moreover, the mineral prisms enclosed within the organic membranes are frequently polycrystalline. In the prismatic layer of the mollusc shell, organic membranes display a dynamics in accordance with the von Neumann–Mullins and Lewis Laws for two-dimensional foam, emulsion and grain growth. Taken together with the facts that we found instances in which the crystals do not obey such laws, and that the same organic membrane pattern can be found even without the mineral infilling, our work indicates that it is the membranes, not the mineral prisms, that control the pattern, and the mineral enclosed within the organic membranes passively adjusts to the dynamics dictated by the...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Clocks run through the history of physics. Galileo conceived of using the pendulum as a timing de... more Clocks run through the history of physics. Galileo conceived of using the pendulum as a timing device on watching a hanging lamp swing in Pisa cathedral; Huygens invented the pendulum clock; and Einstein thought about clock synchronization in his Gedankenexperiment that led to relativity. Stokes derived his law in the course of investigations to determine the effect of a fluid medium on the swing of a pendulum. I sketch the work that has come out of this, Stokes drag, one of his most famous results. And to celebrate the 200th anniversary of George Gabriel Stokes’ birth I propose using the time of fall of a sphere through a fluid for a sculptural clock—a public kinetic artwork that will tell the time. This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
We present the second half of the papers from the Stokes 200 symposium celebrating the bicentenar... more We present the second half of the papers from the Stokes 200 symposium celebrating the bicentenary of George Gabriel Stokes. This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
The year 2019 marked the bicentenary of George Gabriel Stokes, who in 1851 described the drag—Sto... more The year 2019 marked the bicentenary of George Gabriel Stokes, who in 1851 described the drag—Stokes drag—on a body moving immersed in a fluid, and 2020 is the centenary of Christopher Robin Milne, for whom the game of poohsticks was invented; his father A. A. Milne’s The House at Pooh Corner , in which it was first described in print, appeared in 1928. So this is an apt moment to review the state of the art of the fluid mechanics of a solid body in a complex fluid flow, and one floating at the interface between two fluids in motion. Poohsticks pertains to the latter category, when the two fluids are water and air. This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Weak bubble plumes carry liquid from the environment upwards and release it at multiple intermedi... more Weak bubble plumes carry liquid from the environment upwards and release it at multiple intermediate levels in the form of radial intrusive currents. In this study, laboratory experiments are performed to explore the spreading of turbulent axisymmetric bubble plumes in a liquid with linear density stratification. The thickness, volumetric flowrate and spreading rates of multiple radial intrusions of plume fluid were measured by tracking the movement of dye injected at the source of bubbles. The experimental results are compared with scaling predictions. Our findings suggest that the presence of multiple intrusions reduces their spreading rate, compared to that of a single intrusion. This work is of relevance to the spreading of methane plumes issuing from the seabed in the Arctic Ocean, above methane-hydrate deposits. The slower, multiple spreading favours the presence of methane-rich seawater close to the plume, which may reduce the dissolution of methane in the bubbles, and thus p...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Condensed matter is thermodynamically unstable in a vacuum. That is what thermodynamics tells us ... more Condensed matter is thermodynamically unstable in a vacuum. That is what thermodynamics tells us through the relation showing that condensed matter at temperatures above absolute zero always has non-zero vapour pressure. This instability implies that at low temperatures energy must not be distributed equally among atoms in the crystal lattice but must be concentrated. In dynamical systems such concentrations of energy in localized excitations are well known in the form of discrete breathers, solitons and related nonlinear phenomena. It follows that to satisfy thermodynamics such localized excitations must exist in systems of condensed matter at arbitrarily low temperature and as such the nonlinear dynamics of condensed matter is crucial for its thermodynamics. This article is part of the theme issue ‘Stokes at 200 (Part 1)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Although we humans have known since the first smokey campfires of prehistory that our activities ... more Although we humans have known since the first smokey campfires of prehistory that our activities might alter our local surroundings, the nineteenth century saw the first indications that humankind might alter the global environment; what we currently know as anthropogenic climate change. We are now celebrating the bicentenaries of three figures with a hand in the birth of climate science. George Stokes, John Tyndall and John Ruskin were born in August 1819, August 1820 and February 1819, respectively. We look back from the perspective of two centuries following their births. We outline their contributions to climate science: understanding the equations of fluid motion and the recognition of the need to collect global weather data together with comprehending the role in regulating terrestrial temperature played by gases in the atmosphere. This knowledge was accompanied by fears of the Earth’s regression to another ice age, together with others that industrialization was ruining human...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Sir George Gabriel Stokes PRS was for 30 years an inimitable Secretary of the Royal Society and i... more Sir George Gabriel Stokes PRS was for 30 years an inimitable Secretary of the Royal Society and its President from 1885 to 1890. Two hundred years after his birth, Stokes is a towering figure in physics and applied mathematics; fluids, asymptotics, optics, acoustics among many other fields. At the Stokes 200 meeting, held at Pembroke College, Cambridge from 15–18th September 2019, an invited audience of about 100 discussed the state of the art in all the modern research fields that have sprung from his work in physics and mathematics, along with the history of how we have got from Stokes’ contributions to where we are now. This theme issue is based on work presented at the Stokes 200 meeting. In bringing together people whose work today is based upon Stokes’ own, we aim to emphasize his influence and legacy at 200 to the community as a whole. This article is part of the theme issue ‘Stokes at 200 (Part 1)’.
Stingless bees of the genus Tetragonula construct a brood comb with a spiral or a target pattern ... more Stingless bees of the genus Tetragonula construct a brood comb with a spiral or a target pattern architecture in three dimensions. Crystals possess these same patterns on the molecular scale. Here, we show that the same excitable-medium dynamics governs both crystal nucleation and growth and comb construction in Tetragonula , so that a minimal coupled-map lattice model based on crystal growth explains how these bees produce the structures seen in their bee combs.
Chemical gardens are biomimetic plantlike growths formed by a mixture of salts which precipitate ... more Chemical gardens are biomimetic plantlike growths formed by a mixture of salts which precipitate by a combination of the fluid dynamics of convection forced by osmosis, free convection and chemical reactions. Chemical gardens may be implicated in other phenomena which involve precipitation across a colloidal gel membrane that separates two different aqueous solutions, for example, in the context of geophysical pattern formation in geothermal vents, as well as in cement technology and metal corrosion processes. ...
Philosophical Transactions of the Royal Society B: Biological Sciences, 2019
How is sensing carried out by cilia in the mouse node, zebrafish Kupffer's vesicle and simila... more How is sensing carried out by cilia in the mouse node, zebrafish Kupffer's vesicle and similar left–right (LR) organizer organs in other species? Two possibilities have been put forward. In the former, cilia would detect some chemical species in the fluid; in the latter, they would detect fluid flow. In either case, the hypothesis is that an imbalance would be detected between this signalling coming from cilia on the left and right sides of the organizer, which would initiate a cascade of signals leading ultimately to the breaking of LR symmetry in the developing body plan of the organism. We review the evidence for both hypotheses. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’.
We derive from kinetic theory, fluid mechanics and thermodynamics the minimal continuum-level equ... more We derive from kinetic theory, fluid mechanics and thermodynamics the minimal continuum-level equations governing the flow of a binary, non-electrolytic mixture in an isotropic porous medium with osmotic effects. For dilute mixtures, these equations are linear and in this limit provide a theoretical basis for the widely used semi-empirical relations of Kedem & Katchalsky (Kedem & Katchalsky 1958 Biochim. Biophys. Acta 27, 229–246 (doi:10.1016/0006-3002(58)90330-5)), which have hitherto been validated experimentally but not theoretically. The above linearity between the fluxes and the driving forces breaks down for concentrated or non-ideal mixtures, for which our equations go beyond the Kedem–Katchalsky formulation. We show that the heretofore empirical solute permeability coefficient reflects the momentum transfer between the solute molecules that are rejected at a pore entrance and the solvent molecules entering the pore space; it can be related to the inefficiency of a Maxwellian...
Self-organizing precipitation processes, such as chemical gardens forming biomimetic micro- and n... more Self-organizing precipitation processes, such as chemical gardens forming biomimetic micro- and nanotubular forms, have the potential to show us new fundamental science to explore, quantify, and understand nonequilibrium physicochemical systems, and shed light on the conditions for life's emergence. The physics and chemistry of these phenomena, due to the assembly of material architectures under a flux of ions, and their exploitation in applications, have recently been termed chemobrionics. Advances in understanding in this area require a combination of expertise in physics, chemistry, mathematical modeling, biology, and nanoengineering, as well as in complex systems and nonlinear and materials sciences, giving rise to this new synergistic discipline of chemobrionics.
Chemical gardens and clock reactions are two of the best-known demonstration reactions in chemist... more Chemical gardens and clock reactions are two of the best-known demonstration reactions in chemistry. Until now these have been separate categories. We have discovered that a chemical garden confined to two dimensions is a clock reaction involving a phase change, so that after a reproducible and controllable induction period it explodes.
Proceedings of the Royal Society B: Biological Sciences, 2016
The degree to which biological control is exercised compared to physical control of the organizat... more The degree to which biological control is exercised compared to physical control of the organization of biogenic materials is a central theme in biomineralization. We show that the outlines of biogenic calcite domains with organic membranes are always of simple geometries, while without they are much more complex. Moreover, the mineral prisms enclosed within the organic membranes are frequently polycrystalline. In the prismatic layer of the mollusc shell, organic membranes display a dynamics in accordance with the von Neumann–Mullins and Lewis Laws for two-dimensional foam, emulsion and grain growth. Taken together with the facts that we found instances in which the crystals do not obey such laws, and that the same organic membrane pattern can be found even without the mineral infilling, our work indicates that it is the membranes, not the mineral prisms, that control the pattern, and the mineral enclosed within the organic membranes passively adjusts to the dynamics dictated by the...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Clocks run through the history of physics. Galileo conceived of using the pendulum as a timing de... more Clocks run through the history of physics. Galileo conceived of using the pendulum as a timing device on watching a hanging lamp swing in Pisa cathedral; Huygens invented the pendulum clock; and Einstein thought about clock synchronization in his Gedankenexperiment that led to relativity. Stokes derived his law in the course of investigations to determine the effect of a fluid medium on the swing of a pendulum. I sketch the work that has come out of this, Stokes drag, one of his most famous results. And to celebrate the 200th anniversary of George Gabriel Stokes’ birth I propose using the time of fall of a sphere through a fluid for a sculptural clock—a public kinetic artwork that will tell the time. This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
We present the second half of the papers from the Stokes 200 symposium celebrating the bicentenar... more We present the second half of the papers from the Stokes 200 symposium celebrating the bicentenary of George Gabriel Stokes. This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
The year 2019 marked the bicentenary of George Gabriel Stokes, who in 1851 described the drag—Sto... more The year 2019 marked the bicentenary of George Gabriel Stokes, who in 1851 described the drag—Stokes drag—on a body moving immersed in a fluid, and 2020 is the centenary of Christopher Robin Milne, for whom the game of poohsticks was invented; his father A. A. Milne’s The House at Pooh Corner , in which it was first described in print, appeared in 1928. So this is an apt moment to review the state of the art of the fluid mechanics of a solid body in a complex fluid flow, and one floating at the interface between two fluids in motion. Poohsticks pertains to the latter category, when the two fluids are water and air. This article is part of the theme issue ‘Stokes at 200 (part 2)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Weak bubble plumes carry liquid from the environment upwards and release it at multiple intermedi... more Weak bubble plumes carry liquid from the environment upwards and release it at multiple intermediate levels in the form of radial intrusive currents. In this study, laboratory experiments are performed to explore the spreading of turbulent axisymmetric bubble plumes in a liquid with linear density stratification. The thickness, volumetric flowrate and spreading rates of multiple radial intrusions of plume fluid were measured by tracking the movement of dye injected at the source of bubbles. The experimental results are compared with scaling predictions. Our findings suggest that the presence of multiple intrusions reduces their spreading rate, compared to that of a single intrusion. This work is of relevance to the spreading of methane plumes issuing from the seabed in the Arctic Ocean, above methane-hydrate deposits. The slower, multiple spreading favours the presence of methane-rich seawater close to the plume, which may reduce the dissolution of methane in the bubbles, and thus p...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Condensed matter is thermodynamically unstable in a vacuum. That is what thermodynamics tells us ... more Condensed matter is thermodynamically unstable in a vacuum. That is what thermodynamics tells us through the relation showing that condensed matter at temperatures above absolute zero always has non-zero vapour pressure. This instability implies that at low temperatures energy must not be distributed equally among atoms in the crystal lattice but must be concentrated. In dynamical systems such concentrations of energy in localized excitations are well known in the form of discrete breathers, solitons and related nonlinear phenomena. It follows that to satisfy thermodynamics such localized excitations must exist in systems of condensed matter at arbitrarily low temperature and as such the nonlinear dynamics of condensed matter is crucial for its thermodynamics. This article is part of the theme issue ‘Stokes at 200 (Part 1)’.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Although we humans have known since the first smokey campfires of prehistory that our activities ... more Although we humans have known since the first smokey campfires of prehistory that our activities might alter our local surroundings, the nineteenth century saw the first indications that humankind might alter the global environment; what we currently know as anthropogenic climate change. We are now celebrating the bicentenaries of three figures with a hand in the birth of climate science. George Stokes, John Tyndall and John Ruskin were born in August 1819, August 1820 and February 1819, respectively. We look back from the perspective of two centuries following their births. We outline their contributions to climate science: understanding the equations of fluid motion and the recognition of the need to collect global weather data together with comprehending the role in regulating terrestrial temperature played by gases in the atmosphere. This knowledge was accompanied by fears of the Earth’s regression to another ice age, together with others that industrialization was ruining human...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Sir George Gabriel Stokes PRS was for 30 years an inimitable Secretary of the Royal Society and i... more Sir George Gabriel Stokes PRS was for 30 years an inimitable Secretary of the Royal Society and its President from 1885 to 1890. Two hundred years after his birth, Stokes is a towering figure in physics and applied mathematics; fluids, asymptotics, optics, acoustics among many other fields. At the Stokes 200 meeting, held at Pembroke College, Cambridge from 15–18th September 2019, an invited audience of about 100 discussed the state of the art in all the modern research fields that have sprung from his work in physics and mathematics, along with the history of how we have got from Stokes’ contributions to where we are now. This theme issue is based on work presented at the Stokes 200 meeting. In bringing together people whose work today is based upon Stokes’ own, we aim to emphasize his influence and legacy at 200 to the community as a whole. This article is part of the theme issue ‘Stokes at 200 (Part 1)’.
Stingless bees of the genus Tetragonula construct a brood comb with a spiral or a target pattern ... more Stingless bees of the genus Tetragonula construct a brood comb with a spiral or a target pattern architecture in three dimensions. Crystals possess these same patterns on the molecular scale. Here, we show that the same excitable-medium dynamics governs both crystal nucleation and growth and comb construction in Tetragonula , so that a minimal coupled-map lattice model based on crystal growth explains how these bees produce the structures seen in their bee combs.
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Papers by Julyan Cartwright