The BOS and DOS (BathOxfordStrathclyde and DurhamOxfordStrathclyde) Networks
Objectives
The DOS, and its predecessor BOS, network unites researchers with an interest in anisotropy or directionality in materials, be they solids or liquids. The network brings together for the first time leading research groups in continuum mechanics from Durham, Oxford and Strathclyde.
Anisotropy means the "existence of special or distinguished directions" and "reduced symmetry" since all directions are not
physically equivalent. This, in turn, implies directional physical, optical, mechanical and rheological properties that pave the
way for new applications. Nematic liquid crystals are classical examples of anisotropic complex fluids for which the constituent
asymmetric molecules have translational freedom but tend to align along certain preferred directions, leading to longrange
orientational order.
Apala Majumdar leads the Strathclyde side, and specializes in the mathematics and modelling of nematic liquid
crystals, in particular spatiotemporal pattern formation for nematics in confined geometries and how their orientational
anisotropy may be tailored by material properties, geometrical properties and temperature using techniques from the calculus
of variations, algebraic topology, dynamical systems approaches and numerical studies. Her work is largely motivated by
questions in the display industry or new experiments on nanoconfined systems.
Ian Griffiths leads the Oxford side, and has recently started to specialize in anisotropic solids, for example, porous media with nonperiodic pores
and spatially dependent permeabilities. This can be mathematically studied using new techniques in homogenization theory,
with new applications in filtration and environmental problems. A recently studied example concerns a porositygraded filter,
whose porosity varies with depth, such as fibrous filters and ceramic filters. Each of these materials offers the possibility
of improved performance either by filtering out particles more uniformly in the depth or by reducing the pressure required to
drive fluid through the filter, and there is ample scope for new mathematical insights from asymptotics, analysis and upscaling
methods.
Nigel Mottram coled the Strathclyde side until his recent move to the University of Glasgow. He specializes in the mathematics and applications of nematic liquid crystals, with a more recent interest
in bioinspired active liquid crystals. Active liquid crystals are inherently nonequilibrium systems,
constantly producing and dissipating energy with striking and unique mechanical and rheological responses,
such as low Reynolds number turbulence, rapid density fluctuations and exotic singularities.
Active liquid crystals are ubiquitous in biology, common examples being the cell cytoskeleton and the human DNA
and a lot remains to be understood about the active terms in the phenomenological theories for
active systems and the new resulting anisotropies.
Halim Kusumaatmaja leads the Durham side, and is interested in a wide range of soft matter and biological problems which often show anisotropic behaviour. Examples of current interest include phase behaviour on nonuniform curved surfaces, spreading dynamics on structured surfaces, and reconfigurable elastic structures. His work is largely motivated by a strong interest to understand and mimic nature for engineering and industrial applications. He uses a combination of analytical and numerical techniques. The latter include Monte Carlo, Molecular Dynamics, lattice Boltzmann and energy landscape exploration techniques.
Meeting 7: Durham hosted (remote)
13 September 2021
Speakers:

Philip Hands (Edinburgh). Liquid crystal lasers: Lowcost, compact and tuneable light sources.

Debasish Das (Strathclyde). Active chiral particles driven by electric and magnetic fields

Gaetano Napoli (Salento). Cooling a spherical nematic shell

Adam Townsend (Durham). Microorganisms swimming through structured networks: from the point of view of the microorganism

Joseph Cousins (Glasgow). onuniqueness of equilibrium states for a static ridge of nematic liquid crystals

Aurore Loisy (AixMarseille). Selfpropulsion of a drop of active nematic
Meeting 6: Oxford hosted (remote)
18 September 2020
Speakers:

David MacTaggart (University of Glasgow). Anisotropy in magnetohydrodynamics  effects on nonlinear instabilities

Hilary Ockendon (University of Oxford). Recycling carbon fibres.

Sam Avis (Durham University). Reconfigurability of 3D buckled mesostructures.

Jingmin Xia (University of Oxford). A double Landaude Gennes mathematical model of smectic A liquid crystals.

Linda Cummings (New Jersey Institute of Technology). Dewetting and dielectrowetting in thin films of nematic liquid crystal.
Meeting 5: Durham hosted (remote)
8 July 2020
Speakers:

Priya Subramanian (Mathematical Institute, University of Oxford) – Title TBD

Margarita Staykova (Physics, University of Durham) – Tearing of lipid and polymeric membranes upon stretch

Chris Prior (Mathematical Sciences, University of Durham) – Modes of internal buckling of bundle system

Joseph Cousins (Mathematics and Statistics, University of Strathclyde) – A static ridge of nematic liquid crystal

Anders AufderhorstRoberts (Physics, University of Leeds) – Title: TBD
Meeting 4: Strathclyde hosted (remote)
12 May 2020
Speakers:

Francesco Giglio (School of Mathematics and Statistics, University of
Glasgow) – Exact equations of state for nematics

Mark Miller (Department of Chemistry, Durham University) –
Continuum percolation of nanorod mixtures in quadrupole fields

Joshua Walton (Department of Mathematics and Statistics, University of
Strathclyde) – Active Fluid Flows in TwoDimensional Geometries

Elsen TJHung (Department of Physics, Durham University)
– Splaybend phases in 2d liquid crystals: longrange order and beamsplitter

Alison Ramage (Department of Mathematics and Statistics, University of Strathclyde)
– A Moving Mesh Finite Element Methods for Modelling Defects in Liquid Crystals
Meeting 3: Strathclyde
24 September 2019
Speakers:

Apala Majumdar (Bath, Mathematics/Strathclyde, Mathematics and Statistics) – Pattern Formation in Confined Nematic Systems

Josh Walton (Strathclyde, Mathematics and Statistics) – Pressuredriven states in channel flow of active nematic liquid crystals

Oliver Whitehead (Oxford, Mathematics) – Active and passive driving in liquid crystal devices

Oliver Henrich (Strathclyde, Physics) – Microfluidic flow of colloidliquid crystal composite materials

Joseph Cousins (Strathclyde, Mathematics and Statistics) –Nematic liquid crystal flow during the manufacture of liquid crystal devices

Carl Brown (Nottingham Trent, Physics) – Competition of flow and electric field alignment in nematics
Meeting 2: Oxford
22 May 2019
Speakers:
Patrick Farrell (Mathematics, Oxford) – Computing disconnected bifurcation diagrams of partial differential equations
Lidong Fang (Natural Sciences, Shanghai Jiao Tong University) – Bifurcation diagrams in the Landau de Gennes theory on rectangles
Josh Walton (Mathematics and Statistics, Strathclyde) – Ericksen–Leslie and QTensor models of spontaneous flow transitions in active nematic liquid crystals
Marcin MuchaKruczynski (Physics, Bath) – Van der Waals heterostructures
Magdalena Lesniewska (Physics, Strathclyde) – Microfluidic flow of colloid–liquidcrystal composite materials
Andreas Muench – Thinfilm models for an active gel (Mathematics, Oxford)
Meeting 1: Bath
10 April 2019
Speakers:
Selected publications
[1] Flow and nematic director profiles in a microfluidic channel: the interplay of nematic material constants and backflow
S. Mondal, I.M. Griffiths, F. Charlet & A. Majumdar
2018
MDPI Fluids (in press)
[2] Nematohydrodynamics for Colloidal SelfAssembly and Transport Phenomena
S. Mondal, A. Majumdar & I.M. Griffiths
2018
J. Coll. Interf. Sci. (in press)
[3] Solution landscapes in nematic microfluidics
M. Crespo, A. Majumdar, A. Manuel Ramos & I.M. Griffiths.
2017
Physica D, 351352, 113.