73 research outputs found
Data supporting University of Southampton Doctoral thesis 'Simulation of Lubricant Properties and their Interactions with Surfaces'
No full textThis very large dataset (539 GB) is available on request in part or whole please complete the form for access https://library.soton.ac.uk/datarequest
The folders 2_feb_supp4_results.zip up to retrieve_200_reax_comp_archer.zip, include files and results of Chapter 5 of the thesis (Confined NEMD simulations).
The folders 24_Oct_20_3more_temps_pao2_viscos_t150_1_6.50.zip up to finalextra16_t100_9000.zip, include files and results of Chapter 4 of the thesis (Bulk NEMD simulations).
The folders 26_Oct_glyc_t30dens1_10k_1.zip up to the end of the list, include files and results of Chapter 3 of the thesis (EMD simulations)*.
*Note: The last two zips in this list, 9_jan_21_young_file_retrieve_100_ft2_lite_sim_ReaxFF_compression.zip and 9_jan_21_young_file_retrieve_200_ft1_lite_sim_ReaxFF_compression.zip belong to Chapter 5 of the thesis (Confined NEMD simulations)
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The marriage record of Graves, W. H. and Mathas, Mary E
No full textMarriage license for W.H. Graves and Mary E. Mathas. William Groves was the Justice of the Peace
Simulation of Lubricant Properties and their Interactions with Surfaces
No full textThe behaviour of lubricants at operational conditions, such as at high temperatures and pressures, is a topic of great industrial interest. In particular, viscosity and the viscosity-pressure relation are especially important for applications and their determination by computational simulations is very desirable. In this thesis we evaluate methods to compute these quantities based on fully atomistic molecular dynamics simulations which are computationally demanding but also have the potential to be most accurate. We tested several molecules that are used as lubricants, such as 9,10-dimethyloctadecane, main component of PAO-2 base oil, which was used as the main lubricant for our simulations. The methods used for the viscosity simulations are the Green-Kubo equilibrium molecular dynamics (EMD-GK), the direct computation of viscosity from shear during non-equilibrium MD (NEMD) and the use of confined NEMD, where the fluid is confined within explicitly defined iron oxide wall surfaces, at pressures of up to 1.0 GPa and various temperatures (40-150 degrees Celsius). We present the theory behind these methods and investigate how the simulation parameters affect the results obtained, to ensure viscosity convergence with respect to the simulation intervals and all other parameters. We show that by using each method in its regime of applicability, we can achieve good agreement between simulated and measured values. NEMD simulations at high pressures captured zero shear viscosity successfully, while at 40 degrees Celsius EMD-GK is only applicable to pressures up to 0.3 GPa, where the viscosity is lower. In NEMD, longer and multiply repeated simulations reduce the standard deviation of viscosity, which is essential at lower pressures. Additionally, by using confined NEMD simulations, it was demonstrated that the film thickness of the fluid affects viscosity, and as we increase the number of lubricant molecules, we approach the viscosity value of the bulk fluid derived from NEMD simulations.Another aspect of these methods is the choice of the utilised force field for the atomic interactions. This was investigated by selecting three different commonly used force fields. We have explored several methods for calculating viscosity and we obtained results of particular industrial interest.<br/
Data supporting the thesis 'Simulations of rheological properties of lubricants under operational conditions'
No full textThe dataset is divided in
IDEAL : This folder contains the data regarding the result chapter on Ideal mixtures of two esters obtained via LAMMPS software. It contains the input files, output files, jupyter notebooks with the analysis as well as molecular dynamics trajectories and files to reproduce the simulations and data.
MIXTURE2: This folder contains the data regarding the mixture 2 (non-ideal mixtures result chapter) obtained via LAMMPS software. Specifically, it contains the input files, output files, jupyter notebooks with the analysis as well as molecular dynamics trajectories and files to reproduce the simulations and data.
MIXTURE2: This folder contains the data regarding the mixture 2 (non-ideal mixtures result chapter) obtained via LAMMPS software. Specifically, it contains the input files, output files, jupyter notebooks with the analysis as well as molecular dynamics trajectories and files to reproduce the simulations and data.
Bicyclo_Butylbenzene: This folder contains the data regarding the two of the component of the mixtures used in the non-ideal mixtures result chapter obtained via LAMMPS software. Specifically, it contains the input files, output files, jupyter notebooks with the analysis as well as molecular dynamics trajectories and files to reproduce the simulations and data.
Non_ideal_1_2_4GPa and non_ideal_1bar_05GPa : These folders contain the data regarding the mixture 1 of the non-ideal result chapter obtained via LAMMPS software. Specifically, it contains the input files, output files, jupyter notebooks with the analysis as well as molecular dynamics trajectories and files to reproduce the simulations and data.
CONFINED: This folder contains the data regarding the result chapter on confined system obtained via LAMMPS software. It contains the input files, output files, jupyter notebooks with the analysis as well as molecular dynamics trajectories and files to reproduce the simulations and data. Part of the data necessary to reproduce the data in chapter have been published in another thesis, ref. to doi:10.5258/SOTON/D2436
Hematite: This folder contains the data regarding the result chapter on hematite+zddp obtained via the ONETEP software. It contains the input files, output files, jupyter notebooks with the analysis as well as pseudopotential and any file needed to reproduce the work.
this large dataset 515GB is available 'on request' due to size. Please complete the request form at
https://library.soton.ac.uk/datarequest</span
A new broccoli × broccoli immortal mapping population and framework genetic map: tools for breeders and complex trait analysis
No full textA unique broccoli x broccoli doubled haploid (DH) population has been created from the F-1 of a cross between two DH broccoli lines derived from cultivars Green Duke and Marathon. We genotyped 154 individuals from this population with simple sequence repeat and amplified fragment length polymorphism markers to create a B. oleracea L. var. italica 'intra-crop' specific framework linkage map. The map is composed of nine linkage groups with a total length of 946.7 cM. Previous published B. oleracea maps have been constructed using diverse crosses between morphotypes of B. oleracea; this map therefore represents a useful breeding resource for the dissection of broccoli specific traits. Phenotype data have been collected from the population over five growing seasons; the framework linkage map has been used to locate quantitative trait loci for agronomically important broccoli traits including head weight (saleable yield), head diameter, stalk diameter, weight loss and relative weight loss during storage, as well as traits for broccoli leaf architecture. This population and associated linkage map will aid breeders to directly map agronomically important traits for the improvement of elite broccoli cultivars
Evaluation of methods for viscosity simulations of lubricants at different temperatures and pressures: a case study on PAO-2
No full textThe behavior of lubricants at operational conditions, such as at high pressures, is a topic of great industrial interest. In particular, viscosity and the viscosity-pressure relation are especially important for applications and their determination by computational simulations is very desirable. In this study we evaluate methods to compute these quantities based on fully atomistic molecular dynamics simulations which are computationally demanding but also have the potential to be most accurate. We used the 9,10-dimethyloctadecane molecule, main component of PAO-2 base oil as the lubricant for our tests. The methods used for the viscosity simulations are the Green-Kubo equilibrium molecular dynamics (EMD-GK) and non-equilibrium molecular dynamics (NEMD), at pressures of up to 1.0 GPa and various temperatures (40-150 degrees Celsius). We present the theory behind these methods and investigate how the simulation parameters affect the results obtained, to ensure viscosity convergence with respect to the simulation intervals and all other parameters. We show that by using each method in its regime of applicability, we can achieve good agreement between simulated and measured values. NEMD simulations at high pressures captured zero shear viscosity successfully, while at 40 degrees Celsius EMD-GK is only applicable to pressures up to 0.3 GPa, where the viscosity is lower. In NEMD, longer and multiply repeated simulations improve the confidence interval of viscosity, which is essential at lower pressures. Another aspect of these methods is the choice of the utilized force field for the atomic interactions. This was investigated by selecting two different commonly used force fields
General runner removal and the Mullineux map
No full textAbstractWe prove a new ‘runner removal theorem’ for q-decomposition numbers of the level 1 Fock space of type Ae−1(1), generalising earlier theorems of James–Mathas and the author. By combining this with another theorem relating to the Mullineux map, we show that the problem of finding all q-decomposition numbers indexed by partitions of a given weight is a finite computation
Cellularity and subdivision of KLR and weighted KLRW algebras
No full textWeighted KLRW algebras are diagram algebras generalizing KLR algebras. This
paper undertakes a systematic study of these algebras culminating in the
construction of homogeneous affine cellular bases in affine types A and C,
which immediately gives cellular bases for the cyclotomic quotients of these
algebras. In addition, we construct subdivision homomorphisms that relate
weighted KLRW algebras for different quivers. As an application we obtain new
results about the (cyclotomic) KLR algebras of affine type, including
(re)proving that the cyclotomic KLR algebras of type A^{(1)}_{e} and
C^{(1)}_{e} are graded cellular algebras.Comment: 53 pages, revision with several changes, many figures, to appear in
Math. Ann., comments welcom
The Ariki--Koike algebras and Rogers--Ramanujan type partitions
No full textIn 2000, Ariki and Mathas showed that the simple modules of the Ariki--Koike
algebras (when
the parameters are roots of unity and ) are labeled by the so-called
Kleshchev multipartitions. This together with Ariki's categorification theorem
enabled Ariki and Mathas to obtain the generating function for the number of
Kleshchev multipartitions by making use of the Weyl--Kac character formula. In
this paper, we revisit this generating function for the case. This
case is particularly interesting, for the corresponding Kleshchev
multipartitions have a very close connection to generalized Rogers--Ramanujan
type partitions when and . Based on
this connection, we provide an analytic proof of the result of Ariki and Mathas
for and . Our second objective is
to investigate simple modules of the Ariki--Koike algebra in a fixed block. It
is known that these simple modules in a fixed block are labeled by the
Kleshchev multiparitions with a fixed partition residue statistic. This
partition statistic is also studied in the works of Berkovich, Garvan, and
Uncu. Employing their results, we provide two bivariate generating function
identities when
Calculating shear viscosity with confined non-equilibrium molecular dynamics: a case study on hematite - PAO-2 lubricant
No full textThe behaviour of confined lubricants at the atomic scale as affected by the interactions at the surface-lubricant interface is relevant in a range of technological applications in areas such as the automotive industry. In this paper, by performing fully atomistic molecular dynamics, we investigate the regime where the viscosity starts to deviate from the bulk behaviour, a topic of great practical and scientific relevance. The simulations consist of setting up a shear flow by confining the lubricant between iron oxide surfaces. By using confined Non-Equilibrium Molecular Dynamics (NEMD) simulations at a pressure range of 0.1-1.0 GPa at 100 °C, we demonstrate that the film thickness of the fluid affects the behaviour of viscosity. We find that by increasing the number of lubricant molecules, we approach the viscosity value of the bulk fluid derived from previously published NEMD simulations for the same system. These changes in viscosity occurred at film thicknesses ranging from 10.12 to 55.93 Å. The viscosity deviations at different pressures between the system with the greatest number of lubricant molecules and the bulk simulations varied from −16% to 41%. The choice of the utilized force field for treating the atomic interactions was also investigated.</p
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