Search

Your search keyword '"Nordon, Alison"' showing total 340 results
Start Over Author "Nordon, Alison"
340 results on '"Nordon, Alison"'

1. The Effect of Particle Size and Concentration on Low-Frequency Terahertz Scattering in Granular Compacts

Author

Murphy, Keir N, Naftaly, Mira, Nordon, Alison, and Markl, Daniel

Subjects
Physics - Optics, Physics - Applied Physics
Abstract

Fundamental knowledge of scattering in granular compacts is essential to ensure accuracy of spectroscopic measurements and determine material characteristics such as size and shape of scattering objects. Terahertz time-domain spectroscopy (THz-TDS) was employed to investigate the effect of particle size and concentration on scattering in specially fabricated compacts consisting of borosilicate microspheres in a polytetrafluoroethylene (PTFE) matrix. As expected, increasing particle size leads to an increase in overall scattering contribution. At low concentrations, the scattering contribution increases linearly with concentration. Scattering increases linearly at low concentrations, saturates at higher concentrations with a maximum level depending on particle size, and that the onset of saturation is independent of particle size. The effective refractive index becomes sublinear at high particle concentrations and exceeds the linear model at maximum density, which can cause errors in calculations based on it, such as porosity. The observed phenomena are attributed to the change in the fraction of photons propagating ballistically versus being scattered. At low concentrations, photons travel predominately ballistically through the PTFE matrix. At high concentrations, the photons again propagate ballistically through adjacent glass microspheres. In the intermediate regime, photons are predominately scattered.

Published
2023

2. Integrated Continuous Process Design for Crystallisation, Spherical Agglomeration, and Filtration of Lovastatin

Author

Brown, Cameron J., McGinty, John, Islam, Muhammad T., Rajoub, Nazer, Arjmandi-Tash, Omid, Ottoboni, Sara, Shahid, Muhid, Urwin, Stephanie J., Lee, Ye Seol, Chong, Magdalene W. S., Papathanasiou, Foteini, Prakash, Aruna S., Prasad, Elke, Spence, Bronwyn, Sefcik, Jan, Robertson, John, Smith, Rachel, Litster, James D., Price, Chris J., Nordon, Alison, Adjiman, Claire S., and Florence, Alastair J.

Published
2024
Full Text
View/download PDF

4. Digital process design to define and deliver pharmaceutical particle attributes

Author

Urwin, Stephanie J., Chong, Magdalene W.S., Li, Wei, McGinty, John, Mehta, Bhavik, Ottoboni, Sara, Pathan, Momina, Prasad, Elke, Robertson, Murray, McGowan, Mark, al-Attili, Mais, Gramadnikova, Ekaterina, Siddique, Mariam, Houson, Ian, Feilden, Helen, Benyahia, Brahim, Brown, Cameron J., Halbert, Gavin W., Johnston, Blair, Nordon, Alison, Price, Chris J., Reilly, Chris D., Sefcik, Jan, and Florence, Alastair J.

Published
2023
Full Text
View/download PDF

13. Estimation of Particle Size Distribution and Aspect Ratio of Non-Spherical Particles From Chord Length Distribution

Author

Agimelen, Okpeafoh S., Hamilton, Peter, Haley, Ian, Nordon, Alison, Vasile, Massimiliano, Sefcik, Jan, and Mulholland, Anthony J.

Subjects
Physics - Data Analysis, Statistics and Probability
Abstract

Information about size and shape of particles produced in various manufacturing processes is very important for process and product development because design of downstream processes as well as final product properties strongly depend on these geometrical particle attributes. However, recovery of particle size and shape information in situ during crystallisation processes has been a major challenge. The focused beam reflectance measurement (FBRM) provides the chord length distribution (CLD) of a population of particles in a suspension flowing close to the sensor window. Recovery of size and shape information from the CLD requires a model relating particle size and shape to its CLD as well as solving the corresponding inverse problem. This paper presents a comprehensive algorithm which produces estimates of particle size distribution and particle aspect ratio from measured CLD data. While the algorithm searches for a global best solution to the inverse problem without requiring further a priori information on the range of particle sizes present in the population or aspect ratio of particles, suitable regularisation techniques based on relevant additional information can be implemented as required to obtain physically reasonable size distributions. We used the algorithm to analyse CLD data for samples of needle-like crystalline particles of various lengths using two previously published CLD models for ellipsoids and for thin cylinders to estimate particle size distribution and shape. We found that the thin cylinder model yielded significantly better agreement with experimental data, while estimated particle size distributions and aspect ratios were in good agreement with those obtained from imaging., Comment: 30 pages, 9 figures, accepted in the Chemical Engineering Science Journal

Published
2014

14. Measuring proteins in H2O using 2D-IR spectroscopy: pre-processing steps and applications toward a protein library.

Author

Rutherford, Samantha H., Greetham, Gregory M., Parker, Anthony W., Nordon, Alison, Baker, Matthew J., and Hunt, Neil T.

Subjects
BLOOD proteins, SPECTROMETRY, PROTEINS, NOISE control, GEOTHERMAL resources
Abstract

The ability of two-dimensional infrared (2D-IR) spectroscopy to measure the amide I band of proteins in H2O rather than D2O-based solvents by evading the interfering water signals has enabled in vivo studies of proteins under physiological conditions and in biofluids. Future exploitation of 2D-IR in analytical settings, from diagnostics to protein screening, will, however, require comparisons between multiple datasets, necessitating control of data collection protocols to minimize measurement-to-measurement inconsistencies. Inspired by analytical spectroscopy applications in other disciplines, we describe a workflow for pre-processing 2D-IR data that aims to simplify spectral cross-comparisons. Our approach exploits the thermal water signal that is collected simultaneously with, but is temporally separated from the amide I response to guide custom baseline correction and spectral normalization strategies before combining them with Principal Component noise reduction tools. Case studies show that application of elements of the pre-processing workflow to previously published data enables improvements in quantification accuracy and detection limits. We subsequently apply the complete workflow in a new pilot study, testing the ability of a prototype library of 2D-IR spectra to quantify the four major protein constituents of blood serum in a single, label-free measurement. These advances show progress toward the robust data handling strategies that will be necessary for future applications of 2D-IR to pharmaceutical or biomedical problems. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

24. Solid-state NMR studies of inclusion compounds

Author

Nordon, Alison

Subjects
541, Physical chemistry
Abstract

The work contained within this thesis is a study of inclusion compounds using solid-state NMR. Such compounds typically exhibit static and/or dynamic disorder, which precludes the use of diffraction-based techniques to obtain detailed structural information. Hence, due to its ability to probe local environments, solid- state NMR can be used to provide information which would otherwise be inaccessible. However, the dynamic nature of the guest molecules within inclusion compounds can yield unusual results for routinely applied experiments, such as cross polarisation, heteronuclear dipolar decoupling and dipolar dephasing. Therefore, some of the more fundamental aspects of solid-state NMR have first been explored. The inclusion compounds of particular interest are those which contain urea or thiourea as the host species. The ordering of guest molecules and host dynamics have been investigated via both one- and two-dimensional (^13)C and (^1)H NMR experiments for the 2-hydroxyalkane/urea inclusion compounds. For the 1-fluorotetradecane/urea inclusion compound, an approach involving a combination of (^1)H→(^13)C and (^19)F→(^13)C cross-polarisation experiments, with both single-channel (^H) and double-channel decoupling ((^1)H,(^19)F) has been devised to assign (^13)C resonances and hence deduce guest ordering. Steady-state and transient (^19)F MAS NOE experiments have been used to probe the dynamics of the 1-fluorotetradecane/urea inclusion compound. Using the considerable sensitivity advantage of (^19)F NMR, over that of (^13)C, a detailed study of the conformational dynamics exhibited by fluorocyclohexane molecules included within thiourea has been performed via bandshape analysis, selective polarisation inversion and 2D exchange experiments. Intermolecular distance measurements have been determined for adjacent fluoroalkane molecules within urea tunnels using a series of static (^19)F NMR experiments. From the results obtained, conclusions regarding the mutual orientations of adjacent end-groups in such compounds have been made.

Published
1997

30. Temperature Correction of Spectra to Improve Solute Concentration Monitoring by In Situ Ultraviolet and Mid-Infrared Spectrometries toward Isothermal Local Model Performance

Author

Chong, Magdalene W. S., primary, McGlone, Thomas, additional, Chai, Ching Yee, additional, Briggs, Naomi E. B., additional, Brown, Cameron J., additional, Perciballi, Francesca, additional, Dunn, Jaclyn, additional, Parrott, Andrew J., additional, Dallin, Paul, additional, Andrews, John, additional, Nordon, Alison, additional, and Florence, Alastair J., additional

Published
2022
Full Text
View/download PDF

33. The CMAC MicroFactory : mefenamic acid

Author

Chong, Magdalene, Brown, Cameron, Mustoe, Chantal, McGinty, John, Li, Wei, Pathan, Momina, Ottoboni, Sara, Prasad, Elke, Robertson, Murray, Mehta, Bhavik, McGowan, Mark, Siddique, Humera, Raval, Vishal, Pereira Diaz, Laura, Siddique, Mariam, Eales, William, Turner, Alice, Johnston, Blair, Robertson, John, Halbert, Gavin, Price, Chris, Benyahia, Brahim, Rielly, Chris, Sefcik, Jan, Nordon, Alison, McGlone, Thomas, Smith, Kenneth, Feilden, Helen, Houson, Ian, and Florence, Alastair

Subjects
RM
Published
2022

36. Measuring proteins in H2O using 2D-IR spectroscopy: pre-processing steps and applications toward a protein library

Author

Rutherford, Samantha H., Greetham, Gregory M., Parker, Anthony W., Nordon, Alison, Baker, Matthew, Hunt, Neil T., Rutherford, Samantha H., Greetham, Gregory M., Parker, Anthony W., Nordon, Alison, Baker, Matthew, and Hunt, Neil T.

Abstract

The ability of two-dimensional infrared (2D-IR) spectroscopy to measure the amide I band of proteins in H2O rather than D2O-based solvents by evading the interfering water signals has enabled in vivo studies of proteins under physiological conditions and in biofluids. Future exploitation of 2D-IR in analytical settings, from diagnostics to protein screening, will, however, require comparisons between multiple datasets, necessitating control of data collection protocols to minimize measurement-to-measurement inconsistencies. Inspired by analytical spectroscopy applications in other disciplines, we describe a workflow for pre-processing 2D-IR data that aims to simplify spectral cross-comparisons. Our approach exploits the thermal water signal that is collected simultaneously with, but is temporally separated from the amide I response to guide custom baseline correction and spectral normalization strategies before combining them with Principal Component noise reduction tools. Case studies show that application of elements of the pre-processing workflow to previously published data enables improvements in quantification accuracy and detection limits. We subsequently apply the complete workflow in a new pilot study, testing the ability of a prototype library of 2D-IR spectra to quantify the four major protein constituents of blood serum in a single, label-free measurement. These advances show progress toward the robust data handling strategies that will be necessary for future applications of 2D-IR to pharmaceutical or biomedical problems.

Published
2022

37. Deep learning for near-infrared spectral data modelling: Hypes and benefits

Author

Química analítica, Kimika analitikoa, Mishra, Puneet, Passos, Dário, Marini, Federico, Xu, Junli, Amigo Rubio, José Manuel, Gowen, Aoife A., Jansen, Jeroen J., Biancolillo, Alessandra, Roger, Jean Michel, Rutledge, Douglas N., Nordon, Alison, Química analítica, Kimika analitikoa, Mishra, Puneet, Passos, Dário, Marini, Federico, Xu, Junli, Amigo Rubio, José Manuel, Gowen, Aoife A., Jansen, Jeroen J., Biancolillo, Alessandra, Roger, Jean Michel, Rutledge, Douglas N., and Nordon, Alison

Abstract

Deep learning (DL) is emerging as a new tool to model spectral data acquired in analytical experiments. Although applications are flourishing, there is also much interest currently observed in the scientific community on the use of DL for spectral data modelling. This paper provides a critical and compre-hensive review of the major benefits, and potential pitfalls, of current DL tecnhiques used for spectral data modelling. Although this work focuses on DL for the modelling of near-infrared (NIR) spectral data in chemometric tasks, many of the findings can be expanded to cover other spectral techniques. Finally, empirical guidelines on the best practice for the use of DL for the modelling of spectral data are provided.

Published
2022

40. A structured approach to implementation of measurements : crystallisation in the mefenamic acid MicroFactory

Author

Chong, Magdalene, Li, Wei, Brown, Cameron, McGinty, John, Robertson, Murray, Johnston, Blair, Sefcik, Jan, Benyahia, Brahim, Rielly, Chris, and Nordon, Alison

Subjects
RM
Abstract

The CMAC workflow approach Since the development of the seminal workflow for seeded continuous cooling crystallisations, a number of workflows have been developed within CMAC that cover various processes including early stage crystallisation development, impurity rejection, and isolation.

Published
2022
Full Text
View/download PDF

50. Theoretical analysis of ultrasonic vibration spectra from multiple particle-plate impact

Author

Carson, Gillian, Mulholland, Anthony J., Nordon, Alison, Gachagan, Anthony, and Hayward, Gordon

Subjects
Fluid dynamics -- Analysis, Ultrasonic transducers -- Design and construction, Ultrasonic transducers -- Evaluation, Vibrational spectra -- Evaluation, Business, Electronics, Electronics and electrical industries
Abstract

The article presents a new model, which is used for the theoretical analysis of the vibrations that are produced from the multiple particle-plate impact. The study of these vibrations has been shown to be extremely effective in recovering the different particle sizes present in the carrier fluid.

Published
2009

Catalog

Books, media, physical & digital resources
See catalog results