Peter McDonald

Professor Peter McDonald


Professor of Physics
+44 (0)1483 686798
19 BB 03

Biography

Research

Research interests

Research projects

Research collaborations

My teaching

My publications

Publications

ACA Muller, KL Scrivener, Agata Gajewicz, Peter McDonald (2013)Use of bench-top NMR to measure the density, composition and desorption isotherm of C-S-H in cement paste, In: Microporous and Mesoporous Materials178pp. 99-103

H nuclear magnetic resonance (NMR), supported by a measurement of the degree of hydration using X-ray diffraction, has been used to fully characterise the nano-scale porosity and composition of calcium-silicate-hydrate (C-S-H), the active component of cement. The resultant "solid" density and composition are ρ = 2.68 g/cm; (Ca). (Si,Al)O. (HO) for an underwater cured, never-dried cement paste with an initial mix water-to-cement ratio of 0.4 after 28 days of hydration. In addition, the first pore-type resolved desorption isotherm of cement that shows the location of water as a function of relative humidity has been measured. Critical to our results is verification of the assignment of the different NMR spin-spin relaxation time components. These have been corroborated with conventional analyses. The new methodology is key to enabling design of cement pastes with lower environmental impact.

M Zalzale, PJ McDonald (2012)Lattice Boltzmann simulations of the permeability and capillary adsorption of cement model microstructures, In: CEMENT AND CONCRETE RESEARCH42(12)pp. 1601-1610 PERGAMON-ELSEVIER SCIENCE LTD
G Hunter, DM Lane, SN Scrimgeour, PJ McDonald, CH Lloyd (2003)Measurement of the diffusion of liquids into dental restorative resins by stray-field nuclear magnetic resonance imaging (STRAFI), In: DENTAL MATERIALS19(7)pp. 632-638 ELSEVIER SCI LTD
PJ McDonald, MN Turner (2015)Combining e ective media and multi-phase methods of Lattice Boltzmann modelling for the characterisation of liquid-vapour dynamics in multi-length scale heterogeneous structural materials, In: MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING24(1)pp. 1-15 IOP PUBLISHING LTD

The combination of the lattice Boltzmann Shan-Chen pseudo-potential method for multiphase fluids (Shan and Chen 1993 Phys. Rev. E 47 1815) and a grey or partial bounce back lattice Boltzmann algorithm for effective media (Walsh et al 2009 Comput. Geosci. 35 1186), is demonstrated for application to liquid-vapour fluid dynamics in porous media with porosity spanning a very wide range of length scales. Liquid / vapour distributions in cellular like structures with cell walls of reduced permeability are seen to follow expectation

MA Etzold, PJ McDonald, AF Routh (2014)Growth of sheets in 3D confinements - a model for the C-S-H meso structure, In: CEMENT AND CONCRETE RESEARCH63pp. 137-142 PERGAMON-ELSEVIER SCIENCE LTD
E Karakosta, PM Jenneson, RP Sear, PJ McDonald (2006)Observations of coarsening of air voids in a polymer-highly-soluble crystalline matrix during dissolution, In: PHYSICAL REVIEW E74(1)ARTN 0pp. ?-? AMERICAN PHYSICAL SOC
AM Gajewicz, E Gartner, K Kang, PJ McDonald, V Yermakou (2016)A 1H NMR relaxometry investigation of gel-­pore drying shrinkage in cement pastes, In: Cement and Concrete Research86pp. 12-19 Elsevier

The first systematic study of the temporal evolution of the pore-size-distribution (PSD) in mature cement pastes following one and two cycles of drying and rewetting is presented. The PSD is measured using 1H nuclear magnetic resonance (NMR) relaxometry. For millimetre sized paste samples dried fairly strongly, the volume of water taken up shortly after rewetting slightly exceeds the pre-drying amount. The volume of water in pores > 10 nm far exceeds that in smaller pores. This reverses the situation observed prior to drying. Over subsequent days the water distribution reverts to its original form, so that the dominant fraction is again in the smaller pores. Since the total water content scarcely changes, this indicates a re-arrangement of the nano-scale porosity. Over two drying–rewetting cycles, both reversible and irreversible changes are seen. The effect is not observed in moderately dried pastes.

V Rodin, A Valori, PJ McDonald (2011)A 1H double-quantum-filtered NMR study of water in cement pastes, In: New Journal of Physics13035017pp. 1-13 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft

The results of a 1H double-quantum-filtered (DQF) nuclear magnetic resonance (NMR) study of water in cement pastes are reported. It is shown that the DQF signal increases with curing time and in sympathy with the loss of mobile single-quantum signal, suggesting strongly that a signal from 1H in chemically combined and strongly confined water is selectively observed. The DQF signal in white cement comprises at least two components: the first is assigned to portlandite (Ca(OH)2); the second is assigned to water in the planar, nanometre-wide, calcium–silicate–hydrate (C–S–H) gel pores. The pore water signal is significantly broader than that expected for bound water. The width is interpreted in terms of the water undergoing a two-dimensional walk in the vicinity of Fe3+ impurities. A simple model is presented and found to be consistent with experiment and the known Fe3+ concentration. In grey cements, a third component is identified and associated with Fe-rich phases. The analysis places a lower bound on the lateral extent of planar C–S–H pores. The change in DQF signal components upon drying a sample mirrors the loss of the singlequantum components observed in a parallel study.

David Faux, Peter McDonald, NC Howlett (2017)Nuclear magnetic resonance relaxation due to the translational diffusion of fluid confined to quasi-two-dimensional pores, In: Physical Review E95(3)033116 American Physical Society

Nuclear magnetic resonance (NMR) relaxation experimentation is an e ective technique for non-destructively probing the dynamics of proton-bearing uids in porous media. The frequencydependent relaxation rate T−1 1 can yield a wealth of information on the uid dynamics within the pore provided data can be t to a suitable spin di usion model. A spin di usion model yields the dipolar correlation function G(t) describing the relative translational motion of pairs of 1H spins which then can be Fourier transformed to yield T−1 1 . G(t) for spins con ned to a quasi-two-dimensional (Q2D) pore of thickness h is determined using theoretical and Monte Carlo techniques. G(t) shows a transition from three- to two-dimensional (2D) motion with the transition time proportional to h2. T−1 1 is found to be independent of frequency over the range 0.01{100 MHz provided h ? 5 nm and increases with decreasing frequency and decreasing h for pores of thickness h < 3 nm. T−1 1 increases linearly with the bulk water di usion correlation time b allowing a simple and direct estimate of the bulk water di usion coe cient from the high-frequency limit of T−1 1 dispersion measurements in systems where the in uence of paramagnetic impurities is negligible. Monte Carlo simulations of hydrated Q2D pores are executed for a range of surfaceto- bulk desorption rates for a thin pore. G(t) is found to decorrelate when spins move from the surface to the bulk, display three-dimensional properties at intermediate times and nally show a bulk-mediated surface di usion (L evy) mechanism at longer times. The results may be used to interpret NMR relaxation rates in hydrated porous systems in which the paramagnetic impurity density is negligible.

Y Liu, AM Gajewicz, V Rodin, W-J Soer, J Scheerder, G Satgurunathan, Peter McDonald, Joseph Keddie (2016)Explanations for Water Whitening in Secondary Dispersion and Emulsion Polymer Films, In: Journal of Polymer Science, Part B: Polymer Physics54(16)pp. 1658-1674 Wiley

The loss of optical transparency when polymer films are immersed in water, which is called “water whitening,” severely limits their use as clear barrier coatings. It is found that this problem is particularly acute in films deposited from polymers synthesized via emulsion polymerization using surfactants. Water whitening is less severe in secondary dispersion polymers, which are made by dispersing solution polymers in water without the use of surfactants. NMR relaxometry in combination with optical transmission analysis and electron microscopy reveal that some of the water sorbed in emulsion polymer films is contained within nano-sized “pockets” or bubbles that scatter light. In contrast, the water in secondary dispersion polymer films is mainly confined at particle interfaces, where it scatters light less strongly and its molecular mobility is reduced. The addition of surfactant to a secondary dispersion creates a periodic structure that displays a stop band in the optical transmission. The total amount of sorbed water is not a good indicator of polymers prone to water whitening. Instead, the particular locations of the water within the film must be considered. Both the amount of water and the size of the local water regions (as are probed by NMR relaxometry) are found to determine water whitening.

David Faux, PJ McDonald (2017)Explicit calculation of nuclear magnetic resonance relaxation rates in small pores to elucidate molecular scale fluid dynamics, In: Physical Review E: Statistical, Nonlinear, and Soft Matter Physics95(3)03117 American Physical Society

Nuclear magnetic resonance (NMR) spin-lattice (T−1 1 ) and spin-spin (T−1 2 ) relaxation rate mea- surements can act as e ective non-destructive probes of the nano-scale dynamics of 1H spins in porous media. In particular, fast- eld-cycling T−1 1 dispersion measurements contain information on the dynamics of di using spins over time scales spanning many orders of magnitude. Previously- published experimental T−1 1 dispersions from a plaster paste, synthetic saponite, mortar and oil- bearing shale are re-analysed using a model and associated theory which describe the relaxation rate contributions due to the interaction between spins ensembles in quasi-two-dimensional (Q2D) pores. Application of the model yields physically-meaningful di usion correlation times for all systems. In particular, the surface di usion correlation time and the surface desorption time take similar values for each system suggesting that surface mobility and desorption are linked processes. The bulk uid di usion correlation time is found to be 2-5 times the value for the pure liquid at room temperature for each system. Re-analysis of the oil-bearing shale yields di usion time constants for both the oil and water constituents. The shale is found to be oil-wetting and the water T−1 1 dispersion is found to be associated with aqueous Mn2+ paramagnetic impurites in the bulk water. These results escalate the NMR T−1 1 dispersion measurement technique as the primary probe of molecular-scale dynamics in porous media yielding di usion parameters and a wealth of information on pore morphology.

We discuss the effect of paramagnetic impurity content (thought to be predominantly Fe3+) in cement pastes on the interpretation of 1H NMR T2–T2 exchange spectra. Through measurements on synthesised C–S–Hwith greatly reduced paramagnetic impurity concentration, we show that the spectra cannot be explained by exchange between regions of different Fe3+ concentration but rather are explained by exchange between regions of different pore size.

VV Rodin, PJ McDonald, Z Zamani (2013)A nuclear magnetic resonance pulsed field gradient study of self-diffusion of water in hydrated cement pastes, In: Diffusion Fundamentals18(3)pp. 1-7 Diffusion-Fundamentals

The results of one- and two-dimensional 1H nuclear magnetic resonance (NMR) pulsed field gradient (PFG) diffusometry studies of water in white cement paste with a water-to-cement ratio 0.4 and aged from 1 day to 1 year are reported. The study shows that the NMR PFG method is primarily sensitive to the capillary porosity. Data is fit on the basis of a lognormal pore size distribution with pore size dependent relaxation times. The volume mean capillary pore size is 4.2 μm in mature paste, similar to 1 week suggesting that hydrates and gel porosity do not form in the capillary porosity once the latter has been substantially created. No evidence is found of capillary pore anisotropy in cement paste.

E Ciampi, U Goerke, JL Keddie, PJ McDonald (2000)Lateral transport of water during drying of alkyd emulsions, In: LANGMUIR16(3)pp. 1057-1065 AMER CHEMICAL SOC
PJ MCDONALD (1988)A NUCLEAR MAGNETIC-RESONANCE FIELD CYCLING INVESTIGATION OF CHROMIUM AND SILICON DOPED GALLIUM-ARSENIDE, In: SOLID STATE COMMUNICATIONS68(1)pp. 163-166 PERGAMON-ELSEVIER SCIENCE LTD
R Sackin, E Ciampi, J Godward, JL Keddie, PJ McDonald (2001)Fickian ingress of binary solvent mixtures into glassy polymer, In: MACROMOLECULES34(4)pp. 890-895 AMER CHEMICAL SOC
M Jones, PS Aptaker, J Cox, BA Gardiner, PJ McDonald (2012)A transportable magnetic resonance imaging system for in situ measurements of living trees: The Tree Hugger., In: J Magn Reson218pp. 133-140

This paper presents the design of the 'Tree Hugger', an open access, transportable, 1.1MHz (1)H nuclear magnetic resonance imaging system for the in situ analysis of living trees in the forest. A unique construction employing NdFeB blocks embedded in a reinforced carbon fibre frame is used to achieve access up to 210mm and to allow the magnet to be transported. The magnet weighs 55kg. The feasibility of imaging living trees in situ using the 'Tree Hugger' is demonstrated. Correlations are drawn between NMR/MRI measurements and other indicators such as relative humidity, soil moisture and net solar radiation.

PJ McDonald, J Godward, R Sackin, RP Sear (2001)Surface flux limited diffusion of solvent into polymer, In: MACROMOLECULES34(4)pp. 1048-1057 AMER CHEMICAL SOC
M Wallin, PM Glover, AC Hellgren, JL Keddie, PJ McDonald (2000)Depth profiles of polymer mobility during the film formation of a latex dispersion undergoing photoinitiated cross-linking, In: MACROMOLECULES33(22)pp. 8443-8452 AMER CHEMICAL SOC
Mona Ibrahim, C Pardi, Tim Brown, Peter McDonald (2018)Active elimination of radio frequency interference for improved signal-to-noise ratio for in-situ NMR experiments in strong magnetic field gradients, In: Journal of Magnetic Resonance287pp. 99-109 Elsevier

Improvement in the signal-to-noise ratio of Nuclear Magnetic Resonance (NMR) systems may be achieved either by increasing the signal amplitude or by decreasing the noise. The noise has multiple origins – not all of which are strictly “noise”: incoherent thermal noise originating in the probe and pre-amplifiers, probe ring down or acoustic noise and coherent externally broadcast radio frequency transmissions. The last cannot always be shielded in open access experiments. In this paper, we show that pulsed, low radio-frequency data communications are a significant source of broadcast interference. We explore two signal processing methods of de-noising short

JL Keddie, JP Gorce, J Mallégol, PJ McDonald (2004)Understanding water-borne coatings: New techniques to answer old questions, In: Surface Coatings International Part A: Coatings Journal87(2)pp. 70-73
PR Laity, PM Glover, J Godward, PJ McDonald, JN Hay (2000)Structural studies and diffusion measurements of water-swollen cellophane by NMR imaging, In: CELLULOSE7(3)pp. 227-246 KLUWER ACADEMIC PUBL
PDM Hughes, PJ McDonald, EG Smith (1996)Long-range water transport and self-diffusion in zeolite 4A powder beds, In: JOURNAL OF MAGNETIC RESONANCE SERIES A121(2)pp. 147-153 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
Agata Gajewicz-Jaromin, Peter J. McDonald, Arnaud C.A. Muller, Karen L. Scrivener (2019)Influence of curing temperature on cement paste microstructure measured by 1H NMR relaxometry, In: Cement and Concrete Research122pp. 147-156 Elsevier

1H nuclear magnetic resonance (NMR) relaxometry, supported by X-Ray diffraction and thermogravimetric analysis, has been used to characterise microstructure of white cement pastes underwater cured at temperatures in the range 10°C to 60°C. As the temperature increases, so the C-S-H, capillary pore water and interhydrate pore water content all increase; the ettringite and gel pore water content decrease; and the Portlandite content stays constant. A non-linear increase in the C-S-H ‘solid’ and ‘bulk’ densities, that exclude and include gel pore water respectively, has been observed with the increase of temperature. This is accompanied by a decrease in C-S-H water content but no change in the Ca/(Si + Al) ratio. The increase in the C-S-H ‘solid’ density has been attributed to a decrease in the number of locally stacked C-S-H layers. The increase in the C-S-H ‘bulk’ density is additionally attributed to the decrease in the gel porosity.

EG Smith, JW Rockliffe, PJ McDonald, A Lonergan, MR Halse, B Leone, JH Strange (1994)NMR studies of molecular mobility and diffusion in porous systems., In: Magn Reson Imaging12(2)pp. 231-234

The uptake, partitioning, and release of ingredients such as water, oil, surfactant, and ions are important factors to understand and control in the design and manufacture of detergent and personal products. Although conventional pulse NMR (PNMR) spectroscopy continues to be used to analyse bulk molecular mobility and phase composition, more recently MR imaging techniques have created unique opportunities for gaining spatial information about these processes in ways that are noninvasive and potentially quantitative. This paper describes the evaluation of MRI and associated PNMR techniques to study transport in three relevant cases: ion diffusion (e.g., fluoride) in concentrated dispersions, oil transport through powders, and water ingress into porous powders (zeolite). Results are presented to illustrate the potential of multiple pulse and gradient echo MRI methods for dealing with the short T2 scenarios that represent a common problem in quantitative imaging of water in solid-containing composites involving, for instance, zeolite, or silica. Pore-size characterisation results are also presented.

It is shown that broad line gradient echo magnetic resonance imaging is an ideal tool with which to study the ingress of hydrophobic polymer surface treatments into porous building materials, specifically in this case sandstone. It is further shown that the method can be used to quantitatively visualize the movement of water into and through the treated material, both from the surface and bulk, as a function of time. The influence of treatment cure time, cure temperature and substrate hydration on the subsequent water transport have been investigated. For the first time direct evidence of water pumping through a treated surface is presented.

RM Kowalczyk, AM Gajewicz, PJ McDonald (2014)The mechanism of water-isopropanol exchange in cement pastes evidenced by NMR relaxometry, In: RSC ADVANCES4(40)pp. 20709-20715 ROYAL SOC CHEMISTRY
N Fischer, N Fischer, R Haerdtl, PJ McDonald (2015)Is colour change a good measure of a water penetration front?, In: Magazine of Concrete Research67(19)pp. 1048-1053 ICE

© 2015, TELFORD. All rights reserved. GARField nuclear magnetic resonance (NMR) profiling is used to demonstrate that the sharp colour change boundary commonly used to locate the water front in cement and concrete capillary absorption tests is a poor indicator of the true depth of water penetration. Across a range of mortars and concretes, NMR invariably shows a smooth and often nearzero gradient in the degree of saturation at this boundary. Any sharp front that does exist, as might arise from a strong dependence of the effective diffusivity on concentration and a multi-modal pore size distribution on the nanoscale, is always far beyond the colour change line.

DA Faux, SH Cachia, PJ McDonald, JS Bhatt, NC Howlett, SV Churakov (2015)Model for the interpretation of nuclear magnetic resonance relaxometry of hydrated porous silicate materials., In: Phys Rev E Stat Nonlin Soft Matter Phys91(3)pp. 032311-?

Nuclear magnetic resonance (NMR) relaxation experimentation is an effective technique for probing the dynamics of proton spins in porous media, but interpretation requires the application of appropriate spin-diffusion models. Molecular dynamics (MD) simulations of porous silicate-based systems containing a quasi-two-dimensional water-filled pore are presented. The MD simulations suggest that the residency time of the water on the pore surface is in the range 0.03-12 ns, typically 2-5 orders of magnitude less than values determined from fits to experimental NMR measurements using the established surface-layer (SL) diffusion models of Korb and co-workers [Phys. Rev. E 56, 1934 (1997)]. Instead, MD identifies four distinct water layers in a tobermorite-based pore containing surface Ca2+ ions. Three highly structured water layers exist within 1 nm of the surface and the central region of the pore contains a homogeneous region of bulklike water. These regions are referred to as layer 1 and 2 (L1, L2), transition layer (TL), and bulk (B), respectively. Guided by the MD simulations, a two-layer (2L) spin-diffusion NMR relaxation model is proposed comprising two two-dimensional layers of slow- and fast-moving water associated with L2 and layers TL+B, respectively. The 2L model provides an improved fit to NMR relaxation times obtained from cementitious material compared to the SL model, yields diffusion correlation times in the range 18-75 ns and 28-40 ps in good agreement with MD, and resolves the surface residency time discrepancy. The 2L model, coupled with NMR relaxation experimentation, provides a simple yet powerful method of characterizing the dynamical properties of proton-bearing porous silicate-based systems such as porous glasses, cementitious materials, and oil-bearing rocks.

N Fischer, R Haerdtl, PJ McDonald (2015)Observation of the redistribution of nanoscale water filled porosity in cement based materials during wetting, In: CEMENT AND CONCRETE RESEARCH68pp. 148-155 PERGAMON-ELSEVIER SCIENCE LTD
JL Keddie, P Ekanayake, AM Koenig, TG Weerakkody, N Barber, D Johannsmann, RP Sear, PJ McDonald (2007)Influence of the colloidal stability of latex particles on their distribution in drying films, In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY234 AMER CHEMICAL SOC
DA Faux, PJ McDonald, S-H Cachia, N Howlett, M Etzold, A Routh (2015)New nanoscale models for water in cement-based materials

A model linking the molecular-scale dynamics of fluids confined to nano-pores to nuclear magnetic resonance (NMR) relaxation rates is proposed. The model is used to re-analyse fast field-cycling spin-lattice relaxation rate measurements for the separate water and oil dispersions from an oil-bearing shale [Korb et al., J. Phys. Chem. C, 118, 199 (2014)]. The model assumes that pore fluid can be characterized by three time constants: the surface and bulk diffusion correlation times and a surface desorption time constant. Results are shown to yield meaningful and consistent intra-pore dynamical time constants, insight into diffusion mechanisms and pore morphology. The shale is found to be oil-wetting and the water dispersion is found to be due to the interaction of aqueous Mn2+ ions with bulk water spins. Clay, mortar and plaster paste dispersions measurements have also been successfully re-analysed and a summary of the results is presented. The results demonstrate the wide applicability of the model which advances NMR dispersion experimentation as a powerful tool for measuring nano-porous fluid properties.

This Guide is an introduction to the basic concepts of using 1H nuclear magnetic resonance (NMR) relaxometry to determine the state of water in cement, and hence the degree of cure of the cement and the cement microstructure, in particular the porosity. The Guide provides information on calibrating the equipment, the NMR responses that can typically be found from cement and on how to quantify the information obtained. Recommendations are made for the specification of suitable equipment, the set-up procedures required, and the experiments to be performed. Detailed results of an international round robin are included to demonstrate the usability, repeatability and accuracy of the method. The preparation of suitable non-cementitious reference materials is discussed.

R Rodriguez, CDLH Alarcon, P Ekanayake, PJ McDonald, JL Keddie, MJ Barandiaran, JM Asua (2008)Correlation of Silicone Incorporation into Hybrid Acrylic Coatings with the Resulting Hydrophobic and Thermal Properties, In: MACROMOLECULES41(22)pp. 8537-8546 AMER CHEMICAL SOC
KL PERRY, PJ MCDONALD, EW RANDALL, K ZICK (1994)STRAY FIELD MAGNETIC-RESONANCE-IMAGING OF THE DIFFUSION OF ACETONE INTO POLY(VINYL CHLORIDE), In: POLYMER35(13)pp. 2744-2748 ELSEVIER SCI LTD
D. A. Faux, P. J. McDonald (2018)Nuclear-magnetic-resonance relaxation rates for fluid confined to closed, channel, or planar pores, In: Physical Review E98(6)063110 American Physical Society

Fast-field-cycling nuclear-magnetic-resonance (FFC NMR) experimentation measures the spin-lattice relaxation rate T1−1=R1 as a function of NMR frequency f. It is a proven technique for probing the nanoscale dynamics of H1 spins over multiple timescales. In many porous systems, fluid is confined to quasi-zero-dimensional (closed), quasi-one-dimensional (channel), or quasi-two-dimensional (planar) pores. Expressions are presented for R1(f) providing simulated dispersion curves for closed, channel, and planar pores where relaxation is associated with fluid movement relative to fixed relaxation centers in the solid. It is shown that fluid confined to nanosized (1–5 nm) spaces can be identified by submillisecond relaxation times for any geometry. The shape and magnitude of R1(f) is shown to be sensitive to pore geometry at low frequency only if relaxation is dominated by the motion of pore bulk fluid. Relaxation in most porous material is dominated by slow-moving surface fluid. Here, the pore geometry can only be distinguished if the relaxation center density is known a priori and then only at very low frequency. Systems containing mixtures of closed, channel, and planar pores of similar characteristic dimension h would present as three peaks at low frequency with closed pores providing the largest R1 and planar pores the smallest. Pore size and shape variability in real systems is shown to diminish the ability to distinguish the three peaks. We show that the ratio T1/T2, where T2 is the spin-spin relaxation time, is a complex function of h, the surface diffusion time constant τℓ, and NMR frequency for f>1 MHz. It is shown that measurements of T1/T2 at 20 MHz in cement paste and hydrocarbon rock capture information on both τℓ and h.

S CLOUGH, PJ MCDONALD (1982)THE CORRELATION OF METHYL TUNNELLING AND THERMALLY ACTIVATED REORIENTATION .2., In: JOURNAL OF PHYSICS C-SOLID STATE PHYSICS15(29)pp. 1039-1042 IOP PUBLISHING LTD
S Zamani, RM Kowalczyk, PJ McDonald (2014)The relative humidity dependence of the permeability of cement paste measured using GARField NMR profiling, In: Cement and Concrete Research57pp. 88-94 Elsevier

The relative humidity (RH) dependence of the water permeability of cement is calculated from the water concentration profile of a paste exposed to an RH gradient and the desorption isotherm. The profile is measured using GARField, standing for Gradient at Right Angles to Field, NMR. The isotherm is derived from other earlier NMR measurements. The Darcy equation gives the intrinsic permeability as 4.6 × 10 m. The apparent intrinsic permeability to water flow shows a broad "U" shape dependence on RH, with a minimum of 7 × 10 m at RH 55%. The "U" shape is attributed to the fact that the transport mechanism involves a coupling of liquid and vapour modes. The data is further analysed in terms of a model of coupled liquid and vapour diffusion and Darcy flow due to Baroghel-Bouny et al. (Cem. Concr. Res. 2011 41 828) from which the relative liquid water and vapour permeabilities are calculated. They are strongly RH dependent. The former increases with increasing RH; the latter decreases. © 2013 Elsevier Ltd.

PJ MCDONALD, BP TORR (1986)IMPROVEMENT OF SIGNAL TO NOISE IN AUTOMATED NUCLEAR-MAGNETIC-RESONANCE EXPERIMENTS, In: JOURNAL OF PHYSICS E-SCIENTIFIC INSTRUMENTS19(7)pp. 563-563 IOP PUBLISHING LTD
A Valori, PJ McDonald, KL Scrivener (2013)The morphology of C-S-H: Lessons from H nuclear magnetic resonance relaxometry, In: Cement and Concrete Research49pp. 65-81 Elsevier

H nuclear magnetic resonance has been applied to cement pastes, and in particular calcium silicate hydrate (C-S-H), for the characterisation of porosity and pore water interactions for over three decades. However, there is now renewed interest in the method, given that it has been shown to be non-invasive, non-destructive and fully quantitative. It is possible to make measurements of pore size distribution, specific surface area, C-S-H density and water fraction and water dynamics over 6 orders of magnitude from nano- to milli-seconds. This information comes in easily applied experiments that are increasingly well understood, on widely available equipment. This contribution describes the basic experiments for a cement audience new to the field and reviews three decades of work. It concludes with a summary of the current state of understanding of cement pore morphology from the perspective of H NMR. © 2013 Elsevier Ltd. All rights reserved.

TB Benson, PJ McDonald (1995)The application of spin echoes to stray-field imaging, In: JOURNAL OF MAGNETIC RESONANCE SERIES B109(3)pp. 314-317 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
Miryea Nicole Borg, D.A. Faux, P.J. McDonald (2019)Lattice Boltzmann Modelling of Water Transport in Hydrates Agglomerates, In: Proceedings 39th Cement and Concrete Science Conference 2019pp. 1-235 University of Bath
PJ MCDONALD, M PINTERKRAINER (1995)HIGH-PRESSURE NMR-STUDY OF METHYL-GROUP TUNNELING IN DIMETHYL SULFIDE, In: MOLECULAR PHYSICS84(5)pp. 1021-1031 TAYLOR & FRANCIS LTD LONDON
David Faux, Rémi Kogon, Villiam Bortolotti, Peter McDonald (2019)Advances in the Interpretation of Frequency-Dependent Nuclear Magnetic Resonance Measurements from Porous Material, In: Molecules24(20) MDPI

Fast-field-cycling nuclear magnetic resonance (FFC-NMR) is a powerful technique for non-destructively probing the properties of fluids contained within the pores of porous materials. FFC-NMR measures the spin–lattice relaxation rate R1(f) as a function of NMR frequency f over the kHz to MHz range. The shape and magnitude of the R1(f) dispersion curve is exquisitely sensitive to the relative motion of pairs of spins over time scales of picoseconds to microseconds. To extract information on the nano-scale dynamics of spins, it is necessary to identify a model that describes the relative motion of pairs of spins, to translate the model dynamics to a prediction of R1(f) and then to fit to the experimental dispersion. The principles underpinning one such model, the 3τ model, are described here. We present a new fitting package using the 3τ model, called 3TM, that allows users to achieve excellent fits to experimental relaxation rates over the full frequency range to yield five material properties and much additional derived information. 3TM is demonstrated on historic data for mortar and plaster paste samples.

AJ HORSEWILL, PJ MCDONALD, D VIJAYARAGHAVAN (1994)HYDROGEN-BOND DYNAMICS IN BENZOIC-ACID DIMERS AS A FUNCTION OF HYDROSTATIC-PRESSURE MEASURED BY NUCLEAR-MAGNETIC-RESONANCE, In: JOURNAL OF CHEMICAL PHYSICS100(3)pp. 1889-1894 AMER INST PHYSICS
AJ Bohris, B Newling, PJ McDonald, A Raoof, NL Tran (1998)A broad-line nuclear magnetic resonance study of water absorption and transport in fibrous cement roofing tiles, In: JOURNAL OF MATERIALS SCIENCE33(4)pp. 859-867 KLUWER ACADEMIC PUBL
CH Lloyd, SN Scrimgeour, G Hunter, JA Chudek, DM Lane, PJ Mcdonald (1999)Solid state spatially resolved H-1 and F-19 nuclear magnetic resonance spectroscopy of dental materials by stray-field imaging, In: JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE10(6)pp. 369-373 KLUWER ACADEMIC PUBL
TB Benson, PJ McDonald, M Mulheron, SO Nwaubani (1998)The use of magnetic resonance imaging techniques in assessing the uptake of surface treatments and water movement through stone faces, In: Materials and Structures31pp. 423-427

This paper addresses some practical questions regarding the influence of hydrophobic treatments on the movement of water in sandstone. The broad line gradient echo magnetic resonance imaging technique has been used for monitoring the depth of penetration of alkyl alkoxysilane treatment into untreated sandstone and subsequently to visualise the movement and spatial distribution profile of water in the untreated and silane treated sandstone matrix. The experimental results show that the effect of hyrdrophobic treatment depends on whether the stone is in short-term or prolonged contact with water. For short term exposure, the presence of a silane treatment prevents the movement of water into and out of the sandstone matrix. However, after continuous long-term contact with water the hydrophobic treatment is unable to prevent the ingress and internal redistribution of water. The ability of water to infiltrate treated regions of sandstone has significant practical implication for stone structures where deterioration may be due to outward movement of water from the interior to the surface of the stone matrix.

PJ McDonald, JP Korb, J Mitchell, L Monteilhet (2005)Surface relaxation and chemical exchange in hydrating cement pastes: A two-dimensional NMR relaxation study, In: PHYSICAL REVIEW E72(1)ARTN 0pp. ?-? AMERICAN PHYSICAL SOC
S CLOUGH, AJ HORSEWILL, PJ MCDONALD, FO ZELAYA (1985)MOLECULAR TUNNELING MEASURED BY DIPOLE-DIPOLE - DRIVEN NUCLEAR MAGNETIC-RESONANCE, In: PHYSICAL REVIEW LETTERS55(17)pp. 1794-1796 AMERICAN PHYSICAL SOC
PJ MCDONALD, GJ BARKER, S CLOUGH, RM GREEN, AJ HORSEWILL (1986)AN NMR INVESTIGATION OF TUNNELING SIDE-BAND IN DIMETHYL SULFIDE, 2-PENTANONE, 2-HEXANONE AND 2-HEPTANONE USING DOUBLE SIDE-BAND IRRADIATION, In: MOLECULAR PHYSICS57(5)pp. 901-908 TAYLOR & FRANCIS LTD
RM Ibberson, PJ McDonald, M PinterKrainer (1997)The crystal structure determination of dimethylsulphide by high-resolution neutron powder diffraction, In: JOURNAL OF MOLECULAR STRUCTURE415(3)pp. 259-266 ELSEVIER SCIENCE BV
S Black, DM Lane, PJ McDonald, DJ Hannant, M Mulheron, G Hunter, MR Jones (1995)THE VISUALIZATION OF THE INGRESS OF POLYMER TREATMENT COATINGS INTO POROUS BUILDING-MATERIALS BY STRAY-FIELD MAGNETIC-RESONANCE-IMAGING, In: Journal of Materials Science Letters14pp. 1175-1177
PDM HUGHES, PJ MCDONALD, MR HALSE, B LEONE, EG SMITH (1995)WATER DIFFUSION IN ZEOLITE-4-A BEDS MEASURED BY BROAD-LINE MAGNETIC-RESONANCE-IMAGING, In: PHYSICAL REVIEW B51(17)pp. 11332-11338 AMERICAN PHYSICAL SOC
TD Hart, AHL Chamberlain, JM Lynch, B Newling, PJ McDonald (1999)A stray field magnetic resonance study of water diffusion in bacterial exopolysaccharides, In: ENZYME AND MICROBIAL TECHNOLOGY24(5-6)pp. 339-347 ELSEVIER SCIENCE INC
S CLOUGH, AJ HORSEWILL, PJ MCDONALD (1984)METHYL TUNNELLING SPECTROSCOPY AND LEVEL-CROSSING PHENOMENA IN SOLID ACETONE, In: JOURNAL OF PHYSICS C-SOLID STATE PHYSICS17(6)pp. 1115-1125 IOP PUBLISHING LTD
PJ MCDONALD, AJ HORSEWILL, DJ DUNSTAN, N HALL (1989)THE PRESSURE-DEPENDENCE OF METHYL TUNNELLING IN MDBP FROM FIELD-CYCLING NMR-SPECTROSCOPY, In: JOURNAL OF PHYSICS-CONDENSED MATTER1(13)pp. 2441-2444 IOP PUBLISHING LTD
TB BENSON, PJ MCDONALD (1995)PROFILE AMPLITUDE-MODULATION IN STRAY-FIELD MAGNETIC-RESONANCE-IMAGING, In: JOURNAL OF MAGNETIC RESONANCE SERIES A112(1)pp. 17-23 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
PJ MCDONALD, D VIJAYARAGHAVAN, PM DEBENHAM, AJ HORSEWILL (1993)PRESSURE-DEPENDENCE OF METHYL TUNNELING IN SOLID DIACETYL - AN EXTENSION TO THE METHYL THERMOMETER MODEL, In: MOLECULAR PHYSICS78(1)pp. 219-228 TAYLOR & FRANCIS LTD
ACA Muller, KL Scrivener, J Skibsted, AM Gajewicz, PJ McDonald (2015)Influence of silica fume on the microstructure of cement pastes: New insights from H NMR relaxometry, In: Cement and Concrete Research74pp. 116-125 Elsevier

H NMR has been used to characterise white Portland cement paste incorporating 10 wt.% of silica fume. Samples were measured sealed throughout the hydration without sample drying. Paste compositions and C-S-H characteristics are calculated based on H NMR signal intensities and relaxation analysis. The results are compared with a similar study of plain white cement paste. While the presence of silica fume has little influence on C-S-H densities, the chemical composition is impacted. After 28 days of sealed hydration, the Ca/(Si + Al) ratio of the C-S-H is 1.33 and the H2O(Si + Al) ratio is 1.10 when 10% of silica fume is added to the white cement. A densification of the C-S-H with time is observed. There are no major changes in capillary, C-S-H gel and interlayer pore sizes for the paste containing silica fume compared to the plain white cement paste. However, the gel/interlayer water ratio increases in the silica fume blend.

Ors Istok, P.J. McDonald, D.A. Faux, A.M. Gajewicz-Jaromin (2019)Sorption Measurements in Cement Paste using GARField MR Imaging, In: Proceedings 39th Cement and Concrete Science Conference 2019pp. 1-235 University of Bath
JS Bhatt, PJ McDonald, DA Faux, NC Howlett, SV Churakov (2014)NMR Relaxation Parameters from Molecular Simulations of Hydrated Inorganic Nanopores, In: INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY114(18)pp. 1220-1228 WILEY-BLACKWELL
PJ McDonald, DM Lane (1999)Magnetic resonance relaxation and imaging, In: POLYMER SURFACES AND INTERFACES IIIpp. 237-267
Magdalena Janota, Peter McDonald, David Faux, Agata Gajewicz-Jaromin (2019)Upscaling towards applications – water transport in C-S-H agglomerates studied by MRI measurements, In: Proceedings 39th Cement and Concrete Science Conference 2019pp. 1-235 University of Bath
Arifah Abdu Rahaman, D.A. Faux, P. J. McDonald (2019)Molecular Dynamics of Paramagnetic and Water in Hydrates, In: Proceedings 39th Cement and Concrete Science Conference 2019pp. 1-235 University of Bath
PM Glover, PJ McDonald, B Newling (1997)Stray-field imaging of planar films using a novel surface coil, In: JOURNAL OF MAGNETIC RESONANCE126(2)pp. 207-212 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
ACA Muller, KL Scrivener, AM Gajewicz, PJ McDonald (2013)Densification of C-S-H measured by H NMR relaxometry, In: Journal of Physical Chemistry C117(1)pp. 403-412 American Chemical Society

The nanoscale morphology of, and pore water interactions in, calcium silicate hydrate (C-S-H), the active component of cement, remain uncertain. H nuclear magnetic resonance (NMR) can fully characterize the nanoporosity of C-S-H in as-prepared material without the need for damaging sample drying. We use NMR to follow the density of C-S-H in sealed cured pastes as a function of degree of hydration (α) and water to cement ratio. We show clear evidence for C-S-H densification. The C-S-H "solid" density, exclusive of gel pore water, slightly decreases from ρ = 2.73 g/cm at α ≈ 0.4 to 2.65 g/cmat α ≈ 0.9 due to an increase in the number of layers in the nanocrystalline aggregates. In the same range, the C-S-H "bulk" density, including gel water, increases from around 1.8 to 2.1 g/cm. The increase corresponds to a transition from growth of low-density product containing gel pores to higher density product devoid of gel pores. We update Powers' classical model from 1947. In contrast to the single "hydrate" of Powers, NMR differentiates between C-S-H and calcium hydroxide and separates out the interlayer water within the C-S-H. It shows a clear nonlinearity in the growth of the different fractions with α. © 2012 American Chemical Society.

Peter McDonald, Ors Istok, Magdalena Janota, Agata Gajewicz-Jaromin, David Faux (2020)Sorption, anomalous water transport and dynamic porosity in cement paste: a spatially localised 1H NMR relaxation study and a proposed mechanis, In: Cement and Concrete Research Elsevier

The link between anomalous water sorption and dynamic porosity in cement pastes is explored using spatially resolved GARField 1H nuclear magnetic resonance (NMR) relaxation analysis. A model is developed in which the effective capillary diffusion coefficient is dependent on the instantaneous pore size distribution. This and earlier data show changes in pore size distribution resultant from changes in saturation that do not occur instantaneously with changes in degree of saturation. Therefore, it is assumed that the pore size distribution is always relaxing exponentially towards a (saturation de pendent) equilibrium. It follows that the diffusivity is sample history (i.e.time) dependent as well as saturation dependent. This is sufficient to ex plain anomalies in rapid capillary water sorption. The same concepts are applied to slow drying. In this case, porosity changes occur on a timescale much shorter than drying so the system is always in dynamic equilibrium and anomalies are therefore not seen.

TB Benson, PJ McDonald (1995)Developments in STRAFI for the quantitative relaxation analysis of solvent inhibition into polymers, In: BULLETIN OF MAGNETIC RESONANCE, VOL 17, NOS 1-4, DECEMBER 1995pp. 172-173
PJ MCDONALD, D VIJAYARAGHAVAN, PM DEBENHAM, AJ HORSEWILL (1994)THE PRESSURE-DEPENDENCE OF MOLECULAR-DYNAMICS MEASURED BY NMR, In: PHYSICA B202(3-4)pp. 346-350
S BOOTH, S CLOUGH, PJ MCDONALD (1984)NMR DOUBLE SIDEBAND SATURATION SPECTROSCOPY, In: JOURNAL OF PHYSICS C-SOLID STATE PHYSICS17(14)pp. L379-L381 IOP PUBLISHING LTD
S CLOUGH, PJ MCDONALD, FO ZELAYA (1984)THE TRANSITION FROM FREE QUANTUM TUNNELLING TO THERMALLY DRIVEN MOTION OF METHYL-GROUPS, In: JOURNAL OF PHYSICS C-SOLID STATE PHYSICS17(25)pp. 4413-4420 IOP PUBLISHING LTD
A HEIDEMANN, S CLOUGH, PJ MCDONALD, AJ HORSEWILL, K NEUMAIER (1985)TUNNELING MOTIONS OF METHYL-GROUPS IN MANGANESE ACETATE TETRAHYDRATE, In: ZEITSCHRIFT FUR PHYSIK B-CONDENSED MATTER58(2)pp. 141-148 SPRINGER

1H nuclear magnetic resonance (NMR) relaxation analysis of water in progressively dried white cement paste is used to estimate the width and relative specific area of intra-C–S–H sheet pores and inter-C–S–H particle gel pores. The measurement is based on the ratio of solid echo to free induction decay signal amplitudes and the observation that as water is removed, so the surface fraction contributing to the solid echo increases. The intra- and inter-C–S–H pores are found to be 1.5 nm and 4.1 nm thick respectively. The total specific area and volume ratio is 2.4 and 0.88 respectively. The volume ratio of readily evaporable water within the pore types is 0.63. Hence, the sheet porosity is 47% of the total or 38% if based solely on evaporable water. The method is distinct from NMR analyses based on the relaxation time. There is good agreement between the measured widths by the two methods.

PJ McDonald, T Pritchard, SP Roberts (1996)Diffusion of water at low saturation levels into sandstone rock plugs measured by broad line magnetic resonance profiling, In: JOURNAL OF COLLOID AND INTERFACE SCIENCE177(2)pp. 439-445 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
PJ MCDONALD, PF TOKARCZUK (1989)AN NMR MULTIPLE PULSE SEQUENCE FOR THE IMAGING OF SOLIDS USING SINUSOIDALLY DRIVEN MAGNETIC-FIELD GRADIENTS, In: JOURNAL OF PHYSICS E-SCIENTIFIC INSTRUMENTS22(11)pp. 948-951 IOP PUBLISHING LTD
PJ MCDONALD, AR LONERGAN (1992)2-DIMENSIONAL FOURIER-TRANSFORM NMR IMAGING OF SOLIDS USING MULTIPLE PULSE LINE NARROWING, In: PHYSICA B176(3)pp. 173-179 ELSEVIER SCIENCE BV
M Wyrzykowski, Peter McDonald, KL Scrivener, P Lura (2017)Water Redistribution within the Microstructure of Cementitious Materials due to Temperature Changes Studied with 1H NMR, In: Journal of Physical Chemistry C121(50)pp. 27950-27962 American Chemical Society

Changes of water state within the pore structure of cement paste due to temperature changes are followed by means of 1H-proton nuclear magnetic resonance (NMR) relaxation analysis. The study shows that with increasing temperature, the signal due to water contained in the smallest C-S-H interlayer spaces decreases while that from the larger gel pores, and to a lesser extent from the capillary pores, increases. On cooling, the opposite behavior is observed with complete reversibility. The observed changes in water populations appear to be instantaneous compared to the rate of temperature change in the samples. These changes are postulated to be responsible for macroscopically observed changes of relative humidity in pores during heating/cooling and are therefore key in understanding thermal deformations of cement based materials. It is evident that the previous hypothesis of microstructural delayed water transport being responsible for macrostructural delayed thermal deformations can be rejected. Different microstructural mechanisms are discussed that could explain the redistribution in water signals, namely water migration and pore rearrangement mechanisms.

PETER JOHN MCDONALD, MIRYEA NICOLE BORG, DAVID ARTHUR FAUX (2021)Mesoscale modelling of dynamic porosity in cement hydrate gel during a water sorption cycle: a lattice Boltzmann study, In: Cement and concrete research Elsevier

We describe a lattice Boltzmann modelling framework for fluid sorption coupled to a dynamic model of cement hydrate microstructure upon which it is possible to explore ideas of water sorption in cement emergent from NMR and other recent experimental studies. The results of the first simulations using the model are presented. We show that it is possible to extract transport and microstructural relaxation parameters from the simulations that are in good qualitative agreement with experiment. We discuss limitations of the methodology.

PJ McDonald, J Mitchell, M Mulheron, PS Aptaker, J Korb, L Monteilhet (2007)Two-dimensional correlation relaxometry studies of cement pastes performed using a new one-sided NMR magnet, In: Cement and Concrete Research37pp. 303-309

We present preliminary results of the first NMR T(1)-T(2) two-dimensional relaxation Correlation experiments performed using a one-sided NMR system in cement based materials. Two-dimensional correlation relaxometry has itself only recently been demonstrated in cement paste where it proved to be a particularly sensitive probe of pore-water dynamics providing direct information on exchange of water between the gel and capillary pore networks. Further to this we have observed differences in the structural development of a selection of cement pastes throughout the early stages of hydration and verified the theoretical frequency dependence of the ratio T(1)/ T(2). When coupled with instrumentation developments in one-sided NMR magnets the way is opened to detailed, spatially resolved studies of the development of hydration and porosity in the surface layers (top 50 mm) of cementitious materials. A new magnet, suitable for such applications, is discussed. (C) 2006 Elsevier Ltd. All rights reserved.

PJ MCDONALD, JJ ATTARD, DG TAYLOR (1987)A NEW APPROACH TO THE NMR IMAGING OF SOLIDS, In: JOURNAL OF MAGNETIC RESONANCE72(2)pp. 224-229 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
PJ McDonald, AM Gajewicz, R Morrell (2016)1H NMR characterisation of pore water in cement materials, In: Proceedings of the 36th Cement and Concrete Science Conference

This paper presents summary results of a Round Robin Trial to examine the reproducibility and robustness of 1H NMR relaxation analysis of water in cements. The results have elsewhere been used to evidence a good practice guide for the characterization of cement using 1H NMR relaxation analysis. A summary of the good practice is presented

J-P Korb, PJ McDonald, L Monteilhet, AG Kalinichev, RJ Kirkpatrick (2007)Comparison of proton field-cycling relaxometry and molecular dynamics simulations for proton-water surface dynamics in cement-based materials, In: CEMENT AND CONCRETE RESEARCH37(3)pp. 348-350 PERGAMON-ELSEVIER SCIENCE LTD
Peter McDonald, James West (2018)Expanding the skills base, In: Physics Worldpp. 17-17 IOP Publishing Ltd.

The role of a PhD programme is to train students for a career in research – be it at university or in industry. In our experience, almost all physics students who begin a PhD hope for an academic career, yet the overwhelming majority eventually move into industry where they contribute hugely to the research and development of firms. Although this picture seems to be accepted by those now embarking on a PhD, many students still have little idea how they could exploit their physics PhD beyond the narrow confines of their research project. In 2008 – a difficult time for UK physics, which suffered funding cuts and department closures – nine university departments in the south east of England came together to form the South East Physics network (SEPnet). This collaboration helped revive physics in the region by focusing on outreach as well as student employability via a summer industry placement scheme. In 2013 SEPnet launched GRADnet to give PhD physics students greater awareness of opportunities outside academia and a broader set of the skills that are needed to exploit them.

PJ MCDONALD, KL PERRY, SP ROBERTS (1993)A REPETITIVE PULSE VARIANT OF BROADLINE GRADIENT-ECHO MAGNETIC-RESONANCE-IMAGING, In: MEASUREMENT SCIENCE AND TECHNOLOGY4(8)pp. 896-898 IOP PUBLISHING LTD
PF TOKARCZUK, PJ MCDONALD (1992)PROPERTIES AND DERIVATIVES OF THE SOLID-STATE IMAGING SEQUENCE ZIGZAG, In: JOURNAL OF MAGNETIC RESONANCE99(2)pp. 225-234 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
J Mitchell, P Bluemler, PJ McDonald (2006)Spatially resolved nuclear magnetic resonance studies of planar samples, In: PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY48(4)pp. 161-181 PERGAMON-ELSEVIER SCIENCE LTD
MA Etzold, PJ McDonald, DA Faux, AF Routh (2015)Filling of three-dimensional space by two-dimensional sheet growth, In: Physical Review E: Statistical, Nonlinear, and Soft Matter Physics92(4) American Physical Society
JP Gorce, NB Milestone, PJ McDonald (2006)Probing the water phases and microstructure in a model cement blend matrix used for the encapsulation of intermediate level nuclear wastes, In: Materials Research Society Symposium Proceedings932pp. 767-774

The changes in microstructure and content of water phases during hydration of a 3:1 BFS:OPC blend are investigated by Mercury Intrusion Porosimetry (MIP), freeze-drying, Thermal Gravimetric Analysis (TGA) and 1H Nuclear Magnetic Resonance (NMR) relaxometry. MIP indicates that during the blend hydration, a reduction in the population of capillary pores (larger than about 100 nm) occurs while the population of gel pores (smaller than few tens of nanometres) increases. Between 3 and 90 days, the porosity estimated by MIP decreases from about 36% down to 18% while the median pore size decreases from about 140 nm down to 6 nm. 1HNMR relaxometry shows that after 1 day of hydration, nearly 70% of the evaporable water is held in capillary pores while about 30% is present in gel pores. After two weeks, most of the evaporable water (90%) is found in pores smaller than few tens of nanometres. : The amount of evaporable water detected by freeze drying decreases from less than 20 wt.% after one week of hydration down to about 16.3 wt.% after 90 days while the amount of chemical ly bound water related to the degree of advancement of the cement hydration and detected by TGA increases from 8 wt.% to 10.3 wt.%. During hydration the BFS:OPC blend matrix evolves from an open microporous network to one of a poorly connected network of water rich nanopores with increasing amounts of chemically bound water. © 2006 Materials Research Society.

JP Korb, L Monteilhet, PJ McDonald, J Mitchell (2007)Microstructure and texture of hydrated cement-based materials: A proton field cycling relaxometry approach, In: Cement and Concrete Research37pp. 295-302

We show how the measurement of proton nuclear magnetic spin-lattice relaxation as a function of magnetic field strength (and hence nuclear Larmor frequency) can provide reliable information on the microstructure (specific surface area and pore size distribution) throughout the progressive hydration of cement-based materials. We present in details the experimental and theoretical characteristic features of the relaxation dispersion to support an interpretation in terms of coupled solid-liquid relaxation at pore interfaces, surface diffusion, and nuclear paramagnetic relaxation. The measurement does not require any drying temperature modification and is sufficiently fast to be applied continuously during the progressive hydration of the material. Coupling this method with the standard proton nuclear spin relaxation and high resolution NMR allows us to follow the development of micro-scale texture within the material. (C) 2006 Elsevier Ltd. All rights reserved.

SN Scrimgeour, CH Lloyd, G Hunter, JA Chudek, DM Lane, PJ McDonald (1998)Nuclear magnetic resonance imaging of fluoride in solid dental cements., In: JOURNAL OF DENTAL RESEARCH77pp. 785-785 AMER ASSOC DENTAL RESEARCH
DJ Eisenstein, DH Weinberg, E Agol, H Aihara, CA Prieto, SF Anderson, JA Arns, E Aubourg, S Bailey, E Balbinot, R Barkhouser, TC Beers, AA Berlind, SJ Bickerton, D Bizyaev, MR Blanton, JJ Bochanski, AS Bolton, CT Bosman, J Bovy, HJ Brewington, WN Brandt, B Breslauer, J Brinkmann, PJ Brown, JR Brownstein, D Burger, NG Busca, H Campbell, PA Cargile, WC Carithers, JK Carlberg, MA Carr, Y Chen, C Chiappini, J Comparat, N Connolly, M Cortes, RAC Croft, LND Costa, K Cunha, JRA Davenport, K Dawson, ND Lee, GFPD Mello, FD Simoni, J Dean, S Dhital, A Ealet, GL Ebelke, EM Edmondson, JM Eiting, S Escoffier, M Esposito, ML Evans, X Fan, BF Castella, LD Ferreira, G Fitzgerald, SW Fleming, A Font-Ribera, EB Ford, PM Frinchaboy, AEG Perez, BS Gaudi, J Ge, L Ghezzi, BA Gillespie, G Gilmore, L Girardi, JR Gott, A Gould, EK Grebel, JE Gunn, J-C Hamilton, P Harding, DW Harris, SL Hawley, FR Hearty, JIG Hernandez, S Ho, DW Hogg, JA Holtzman, K Honscheid, N Inada, II Ivans, L Jiang, P Jiang, JA Johnson, C Jordan, WP Jordan, G Kauffmann, E Kazin, D Kirkby, MA Klaene, J-P Kneib, GR Knapp, CS Kochanek, L Koesterke, JA Kollmeier, RG Kron, D Lang, JE Lawler, J-ML Goff, BL Lee, YS Lee, JM Leisenring, Y-T Lin, J Liu, DC Long, CP Loomis, S Lucatello, B Lundgren, RH Lupton, B Ma, Z Ma, N MacDonald, C Mack, S Mahadevan, MAG Maia, E Malanushenko, V Malanushenko, SR Majewski, M Makler, R Mandelbaum, C Maraston, D Margala, P Maseman, KL Masters, CK McBride, P McDonald, ID McGreer, RG McMahon, OM Requejo, B Menard, J Miralda-Escude, HL Morrison, F Mullally, D Muna, H Murayama, AD Myers, T Naugle, AF Neto, DC Nguyen, RC Nichol, DL Nidever, RW O'Connell, RLC Ogando, MD Olmstead, DJ Oravetz, N Padmanabhan, M Paegert, N Palanque-Delabrouille, K Pan, P Pandey, JK Parejko, I Paris, P Pellegrini, J Pepper, WJ Percival, P Petitjean, R Pfaffenberger, J Pforr, S Phleps, C Pichon, MM Pieri, F Prada, AM Price-Whelan, MJ Raddick, BHF Ramos, C Ryle, IN Reid, J Rich, GT Richards, GH Rieke, MJ Rieke, H-W Rix, AC Robin, HJ Rocha-Pinto, CM Rockosi, NA Roe, E Rollinde, AJ Ross, NP Ross, B Rossetto, AG Sanchez, B Santiago, C Sayres, R Schiavon, DJ Schlegel, KJ Schlesinger, SJ Schmidt, DP Schneider, K Sellgren, A Shelden, E Sheldon, M Shetrone, Y Shu, JD Silverman, J Simmerer, AE Simmons, T Sivarani, MF Skrutskie, A Slosar, S Smee, VV Smith, SA Snedden, KG Stassun, O Steele, M Steinmetz, MH Stockett, T Stollberg, MA Strauss, M Tanaka, AR Thakar, D Thomas, JL Tinker, BM Tofflemire, R Tojeiro, CA Tremonti, MV Magana, L Verde, NP Vogt, DA Wake, X Wan, J Wang, BA Weaver, M White, SDM White, JC Wilson, JP Wisniewski, WM Wood-Vasey, B Yanny, N Yasuda, C Yeche, DG York, E Young, G Zasowski, I Zehavi, B Zhao (2011)SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems, In: Astron.J.142pp. 72-?

Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic surveys on three scientific themes: dark energy and cosmological parameters, the history and structure of the Milky Way, and the population of giant planets around other stars. In keeping with SDSS tradition, SDSS-III will provide regular public releases of all its data, beginning with SDSS DR8 (which occurred in Jan 2011). This paper presents an overview of the four SDSS-III surveys. BOSS will measure redshifts of 1.5 million massive galaxies and Lya forest spectra of 150,000 quasars, using the BAO feature of large scale structure to obtain percent-level determinations of the distance scale and Hubble expansion rate at z100 per resolution element), H-band (1.51-1.70 micron) spectra of 10^5 evolved, late-type stars, measuring separate abundances for ~15 elements per star and creating the first high-precision spectroscopic survey of all Galactic stellar populations (bulge, bar, disks, halo) with a uniform set of stellar tracers and spectral diagnostics. MARVELS will monitor radial velocities of more than 8000 FGK stars with the sensitivity and cadence (10-40 m/s, ~24 visits per star) needed to detect giant planets with periods up to two years, providing an unprecedented data set for understanding the formation and dynamical evolution of giant planet systems. (Abridged)

S CLOUGH, PJ MCDONALD (1983)THE NUMBER OF SPIN SYMMETRY SPECIES OF TUNNELLING MOLECULAR GROUPS, In: JOURNAL OF PHYSICS C-SOLID STATE PHYSICS16(30)pp. 5753-5764 IOP PUBLISHING LTD
B Newling, PM Glover, JL Keddie, DM Lane, PJ McDonald (1997)Concentration profiles in creaming oil-in-water emulsion layers determined with stray field magnetic resonance imaging, In: LANGMUIR13(14)pp. 3621-3626 AMER CHEMICAL SOC
J Mallegol, JP Gorce, O Dupont, C Jeynes, PJ McDonald, JL Keddie (2002)Origins and effects of a surfactant excess near the surface of waterborne acrylic pressure-sensitive adhesives, In: LANGMUIR18(11)pp. 4478-4487 AMER CHEMICAL SOC
E Karakosta, PJ McDonald (2007)An MRI analysis of the dissolution of a soluble drug incorporated within an insoluble polymer tablet, In: APPLIED MAGNETIC RESONANCE32(1-2)pp. 75-91 SPRINGER WIEN
JL Keddie, E Ciampi, PJ McDonald, JM Salamanca (1999)Magnetic resonance imaging of the film formation of waterborne coatings., In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY218pp. U621-U621 AMER CHEMICAL SOC
PJ McDonald, EP O'Reilly (1989)Ultrasound speedometer, In: Physics Education24(4)pp. 237-239
PM Glover, PS Aptaker, JR Bowler, E Ciampi, PJ McDonald (1999)A novel high-gradient permanent magnet for the profiling of planar films and coatings, In: JOURNAL OF MAGNETIC RESONANCE139(1)pp. 90-97 ACADEMIC PRESS INC
PJ McDonald, EP O'Reilly (1989)Vibrating-bar depth gauge, In: Physics Education24(4)pp. 239-240
PJ McDonald, PS Aptaker, J Mitchell, M Mulheron (2007)A unilateral NMR magnet for sub-structure analysis in the built environment: The Surface GARField, In: Journal of Magnetic Resonance185pp. 1-11

A new, portable NMR magnet with a tailored magnetic field profile and a complementary radio frequency sensor have been designed and constructed for the purpose of probing in situ the sub-surface porosity of cement based materials in the built environment. The magnet is a one sided device akin to a large NMR-MOUSE with the additional design specification of planes of constant field strength vertical bar B(0)vertical bar parallel to the surface. There is a strong gradient G in the field strength perpendicular to these planes. As with earlier GARField magnets, the ratio G/vertical bar B(0)vertical bar is a system constant although the method of achieving this condition is substantially different. The new magnet as constructed is able to detect signals 50 mm ((1)H NMR at 3.2 MHz) away from the surface of the magnet and can profile the surface layers of large samples to a depth of 35-40 mm by moving the magnet, and hence the resonant plane of the polarising field, relative to the sample surface. The matching radio frequency excitation/detector coil has been designed to complement the static magnetic field such that the polarising B(0) and sensing B(1) fields are, in principal, everywhere orthogonal. Preliminary spatially resolved measurements are presented of cement based materials, including two-dimensional T(1)-T(2) relaxation correlation spectra. (c) 2007 Published by Elsevier Inc.

Mateusz Wyrzykowski, Agata Gajewicz-Jaromin, Peter J McDonald, David J Dunstan, Karen L. Scrivener, Pietro Lura (2019)Water Redistribution-Microdiffusion in Cement Paste Under Mechanical Loading Evidenced by 1H NMR, In: The Journal of Physical Chemistry C123(26)pp. 16153-16163 American Chemical Society

The mobility of water within the microstructure of hardened cement paste has been at the center of a long-lasting debate, motivated by the need to understand the fundamental mechanisms that play a role in drying, shrinkage, creep and thermal expansion. Our 1H NMR results show for the first time that externally-applied pressure can lead to migration of water within the microstructure (microdiffusion). Upon compression, the gel water signal decreases. For the most part, this is accommodated by a corresponding increase in the signal of water in larger, interhydrate and capillary spaces. However, there is also an increase in the signal corresponding to the water in most confined spaces. Normally such tiny spaces are classified as hydrate interlayers. However, we do not conclude that there is a significant increase in interlayer water. Rather we attribute this part of the increase to a rearrangement of the microstructure upon compression with some water confined in increasingly small gel pore spaces. These findings show that the deformability of the microstructure (C-S-H gel) at the expense of gel porosity may explain part of the macroscopic deformations due to short-term creep.

Robin Adey-Johnson, J. Sam Henderson, David A. Faux, Paul J. Mclean, Peter J. McDonald (2018)Lattice boltzmann modelling of the water sorption cycle in a model wood microstructure: the role of cell wall pits and preliminary results for water induced swelling, In: Proceedings of Timber 2018 The Institute of Materials, Minerals and Mining (IOM3)

This paper describes results that combine Shan-Chen two-phase (liquid-vapour) and partial-bounce back (semi-permeable membrane) methods of Lattice Boltzmann numerical modelling of fluid dynamics in order to understand how bordered pits influence the drying and rewetting of wood. In addition, preliminary results that introduce pressure induced distortion are included.

Robin Adey-Johson, J. Paul Mclean, Jan Van den Bulcke, Joris Van Acker, Peter J. McDonald (2018)A geometrical model of softwood anatomy for fluid mechanics simulations, In: Proceedings of Timber 2018pp. 1-5 The Institute of Materials, Minerals and Mining (IOM3)

This paper demonstrates a model of softwood geometry that can be used for multiscale modelling of the longitudinal movement of water through spruce wood. Previous results obtained from a high resolution X-ray CT scan and subsequent image analysis of a large number of Norway spruce tracheids were here used to produce a model that can represent the variability in wood anatomy found within a timber joist or log. A demonstration of that model is given.

PJ McDonald, E Ciampi, JL Keddie, M Heidenreich, R Kimmich (1999)Magnetic-resonance determination of the spatial dependence of the droplet size distribution in the cream layer of oil-in-water emulsions: Evidence for the effects of depletion flocculation, In: Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics59(1)pp. 874-884 The American Physical Society

It is shown that a combination of pulsed-field-gradient spin-echo ~PGSE! nuclear-magnetic-resonance~NMR! restricted diffusion analysis and NMR imaging may be used to measure the spatial dependence of the droplet size distribution in the cream layer of turbid oil-in-water emulsions. 1H-13C cyclic J cross-polarization PGSE is introduced as a technique for this purpose in cases where selective observation of the oil component ~or other carbohydrate constituent! is required. With this method, 13C nuclei are chemical shift selectively excited by cross-polarization from coupled 1H partners. An optimum detection sensitivity is ensured by transferring the polarization back to the coupled protons with which the combined imaging and diffusion experiment is then carried out. The spatial dependence of the oil droplet size distribution was measured for a series of emulsions containing various fractions of gum xanthan thickener dissolved in the water. The experimental results are compared with a recent model of the creaming process due to Pinfield, Dickinson, and Povey @J. Colloid Interface Sci. 166, 363 ~1994!#. When no gum xanthan is present, the experimental results are in good agreement with the model. However, the model fails to describe the droplet distribution for emulsions with a gum xanthan concentration of the order of 0.1 wt %. The discrepancy is discussed in terms of depletion flocculation and depletion stabilization.

J Mallegol, G Bennett, PJ McDonald, JL Keddie, O Dupont (2006)Skin development during the film formation of waterborne acrylic pressure-sensitive adhesives containing tackifying resin, In: J ADHESION82(3)pp. 217-238 TAYLOR & FRANCIS LTD
J Boguszynska, MCA Brown, PJ McDonald, J Mitchell, M Mulheron, J Tritt-Goc, DA Verganelakis (2005)Magnetic resonance studies of cement based materials in inhomogeneous magnetic fields, In: Cement and Concrete Research35pp. 2033-2040

Single-sided magnets give hope that Nuclear Magnetic Resonance (NMR) might in future be used for in situ characterisation of hydration and water transport in the surface layers of concrete slabs. Towards that end, a portable NMR-MOUSE (MObile Universal Surface Explorer) has been used to follow the hydration of gypsum based plaster, a Portland cement paste and concrete mortar. The results compare favourably to those obtained using a standard laboratory bench-top spectrometer. Further, stray field imaging (STRAFI) based methods have been used with embedded NMR detector coils to study water transport across a mortar/topping interface. The measured signal amplitudes are found to correlate with varying sample conditions. (c) 2005 Elsevier Ltd. All rights reserved.

M Zalzale, PJ McDonald, KL Scrivener (2013)A 3D lattice Boltzmann effective media study: understanding the role of C-S-H and water saturation on the permeability of cement paste, In: MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING21(8)ARTN 0pp. ?-? IOP PUBLISHING LTD
Robert Schulte Holthausen, Peter McDonald (2020)On the quantification of solid phases in hydrated cement paste by 1H nuclear magnetic resonance relaxometry, In: Cement and Concrete Research135106095 Elsevier

Different solid phases, important to cement paste hydration, are investigated with low-field benchtop 1H nuclear magnetic resonance (NMR). A combination of the well-established quadrature echo pulse sequence with variable pulse gap together with a T1 saturation recovery quadrature echo pulse sequence is used. The results illustrate the diversity in the 1H NMR relaxation behaviour of solid phases that prospects the differentiation in more complex materials. We propose a procedure to obtain quantified values of the solid compounds using these unique relaxation responses of solids, called finger print, and apply this technique to well-hydrated white and ordinary Portland cement paste. Based on the results, needs and ways for future improvements are discussed.

M Cifelli, PJ McDonald, CA Veracini (2004)Translational self diffusion in 4-n-octyloxy-4 '-cyanobiphenyl (8OCB) exploited with a static field gradient H-1 NMR diffusometry approach, In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS6(19)pp. 4701-4706 ROYAL SOC CHEMISTRY
J Cox, PJ McDonald, BA Gardiner (2010)A study of water exchange in wood by means of 2D NMR relaxation correlation and exchange, In: HOLZFORSCHUNG64(2)pp. 259-266 WALTER DE GRUYTER & CO
E Ciampi, U Goerke, PJ McDonald, JG Chambers, B Newling (2002)Spatially-resolved magnetic resonance study of the dissolution interface between soaps and water, In: JOURNAL OF PHYSICS D-APPLIED PHYSICS35(11)PII S0022-pp. 1271-1281 IOP PUBLISHING LTD
I Hopkinson, RAL Jones, S Black, DM Lane, PJ McDonald (1997)Fickian and Case II diffusion of water into amylose: a stray field NMR study, In: CARBOHYDRATE POLYMERS34(1-2)pp. 39-47 ELSEVIER SCI LTD
L Monteilhet, J-P Korb, J Mitchell, PJ McDonald (2006)Observation of exchange of micropore water in cement pastes by two-dimensional T-2-T-2 nuclear magnetic resonance relaxometry, In: PHYSICAL REVIEW E74(6)ARTN 0pp. ?-? AMERICAN PHYSICAL SOC
E Ciampi, M van Ginkel, PJ McDonald, S Pitts, EY Bonnist, S Singleton, AM Williamson (2011)Dynamic in vivo mapping of model moisturiser ingress into human skin by GARfield MRI., In: NMR Biomed24(2)pp. 135-144

We describe the development of in vivo one-dimensional MRI (profiling) using a GARField (Gradient At Right angles to Field) magnet for the characterisation of side-of-hand human skin. For the first time and in vivo, we report measurements of the NMR longitudinal and transverse relaxation parameters and self-diffusivity of the upper layers of human skin with a nominal spatial resolution better than 10 µm. The results are correlated with in vivo confocal Raman spectroscopy measurements of water concentration and natural moisturiser factors, and discussed in terms of known skin biology and microstructure of the stratum corneum and viable epidermis. The application of model moisturiser solutions to the skin is followed and their dynamics of ingress are characterised using the MRI methodology developed. Selected hydrophilic and lipophilic formulations are studied. The results are corroborated by standard in vivo measurements of transepidermal water loss and hydration status. A further insight into moisturisation mechanisms is gained. The effect of two different penetration enhancers on a commonly used skin care oil is also discussed, and different timescales of oil penetration into the skin are reported depending on the type of enhancer.

JM Salamanca, E Ciampi, DA Faux, PM Glover, PJ McDonald, AF Routh, ACIA Peters, R Satguru, JL Keddie (2001)Lateral drying in thick films of waterborne colloidal particles, In: LANGMUIR17(11)pp. 3202-3207 AMER CHEMICAL SOC
JP Gorce, D Bovey, PJ McDonald, P Palasz, D Taylor, JL Keddie (2002)Vertical water distribution during the drying of polymer films cast from aqueous emulsions, In: EUROPEAN PHYSICAL JOURNAL E8(4)pp. 421-429 SPRINGER-VERLAG
DA Faux, PJ McDonald, NC Howlett, JS Bhatt, SV Churakov (2013)Nuclear magnetic resonance relaxometry of water in two and quasi-two dimensions, In: PHYSICAL REVIEW E87(6)ARTN 0pp. ?-? AMER PHYSICAL SOC
M Dias, J Hadgraft, PM Glover, PJ McDonald (2003)Stray field magnetic resonance imaging: a preliminary study of skin hydration, In: JOURNAL OF PHYSICS D-APPLIED PHYSICS36(4)PII S0022-pp. 364-368 IOP PUBLISHING LTD
A Chowdhury, A Gillies, PJ McDonald, M Mulheron (2001)Vapour phase application of hydrophobic coatings to cement-based materials, In: Magazine of Concrete Research53pp. 347-352

A new method of applying hydrophobic coatings to cement-based materials based on exposure to the treatment vapour is proposed. The method is demonstrated for the application of monomeric alkyl (isobutyl) alkoxy silane to cement paste and mortar samples manufactured and cured under a variety of conditions. The efficacy of the treatment is compared to conventional flood coating using magnetic resonance imaging (specifically SPRITE) to monitor the time dependent uptake of water into treated samples. It is concluded that the method as proposed is of significant benefit for some of the samples.

I Hopkinson, RAL Jones, PJ McDonald, B Newling, A Lecat, S Livings (2001)Water ingress into starch and sucrose : starch systems, In: POLYMER42(11)pp. 4947-4956 ELSEVIER SCI LTD
J Mallegol, AM Barry, E Ciampi, PM Glover, PJ McDonald, JL Keddie, M Wallin, A Motiejauskaite, PK Weissenborn (2002)Influence of drier combination on through-drying in waterborne alkyd emulsion coatings observed with magnetic resonance profiling, In: JOURNAL OF COATINGS TECHNOLOGY74(933)pp. 113-124 FEDERATION SOC COATING TECH
AC Hellgren, M Wallin, PK Weissenborn, PJ McDonald, PM Glover, JL Keddie (2001)New techniques for determining the extent of crosslinking in coatings, In: PROGRESS IN ORGANIC COATINGS43(1-3)pp. 85-98
SP ROBERTS, PJ MCDONALD, T PRITCHARD (1995)A BULK AND SPATIALLY-RESOLVED NMR RELAXATION STUDY OF SANDSTONE ROCK PLUGS, In: JOURNAL OF MAGNETIC RESONANCE SERIES A116(2)pp. 189-195 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
P McDonald, J Strange (1998)Magnetic resonance and porous materials, In: PHYSICS WORLD11(7)pp. 29-34 IOP PUBLISHING LTD
PJ McDonald (1997)Stray field magnetic resonance imaging, In: PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY30pp. 69-99 PERGAMON-ELSEVIER SCIENCE LTD
JL Keddie, JP Gorce, J Mallegol, M Wallin, AM Barry, E Ciampi, A Motiejauskaite, PM Glover, PJ McDonald, PK Weissenborn (2001)MR profiling of film formation and crosslinking in waterborne alkyd emulsions and emulsion paints., In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY222pp. U378-U378 AMER CHEMICAL SOC
DF Brougham, AJ Horsewill, A Ikram, RM Ibberson, PJ McDonald, M PinterKrainer (1996)The correlation between hydrogen bond tunneling dynamics and the structure of benzoic acid dimers, In: JOURNAL OF CHEMICAL PHYSICS105(3)pp. 979-982 AMER INST PHYSICS
J Godward, E Ciampi, M Cifelli, PJ McDonald (2002)Multidimensional imaging using combined stray field and pulsed gradients, In: JOURNAL OF MAGNETIC RESONANCE155(1)pp. 92-99 ACADEMIC PRESS INC ELSEVIER SCIENCE
PJ McDonald, J Mitchell, M Mulheron, L Monteilhet, J Korb (2007)Two-dimensional correlation relaxation studies of cement pastes, In: Magnetic Resonance Imaging25pp. 470-473

Two-dimensional nuclear magnetic resonance relaxation correlation studies of cement pastes have been performed on a unilateral magnet, the Surface GARField. Through these measurements, the hydration process can be observed by monitoring the evolution of porosity. Characteristic relaxation time distributions have been observed in different cement pastes: fresh white cement, prehydrated white cement and ordinary Portland cement. The observed T-1/T-2 ratio in these cements has been shown to agree with expectations based on high field values. (C)) 2007 Elsevier Inc. All rights reserved.

AJ Bohris, U Goerke, PJ McDonald, M Mulheron, B Newling, B Le Page (1998)A broad line NMR and MRI study of water and water transport in Portland cement pastes, In: Magnetic Resonance Imaging16pp. 455-461

The results of a magnetic resonance spin-spin relaxation analysis and broad-line magnetic resonance imaging (MRI) (gradient-echo and stray-held imaging) study of water and water transport in Portland cement pastes are presented. The effect of varying the cure conditions and the water to cement (w/c) ratio of the sample mix are discussed. The water sorptivity and the concentration dependence of the hydraulic diffusion coefficient are calculated for samples prepared with a 0.5 w/c ratio and, therefore, an open pore structure. In the case of 0.3 w/c ratio samples, little water transport is observed, and a closed pore structure is inferred. (C) 1998 Elsevier Science Inc.

JJ Attard, PJ McDonald, SP Roberts, T Taylor (1994)Solid state NMR imaging of irreducible water in reservoir cores for spatially resolved pore surface relaxation estimation., In: Magn Reson Imaging12(2)pp. 355-359

The use of solid state NMR imaging in reservoir core applications has long been proposed. This paper describes the use of a simple, robust technique in the first such application. One- and two-dimensional images of the irreducible brine in a sandstone and carbonate reservoir core are demonstrated. The applicability of solid state NMR imaging to pore surface relaxation estimation is discussed.

PDM Hughes, PJ McDonald, NP Rhodes, JW Rockliffe, EG Smith, J Wills (1996)A stray field magnetic resonance imaging study of the drying of sodium silicate films, In: JOURNAL OF COLLOID AND INTERFACE SCIENCE177(1)pp. 208-213 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
PJ McDonald, A Akhmerov, LJ Backhouse, S Pitts (2005)Magnetic resonance profiling of human skin in vivo using GARField magnets, In: JOURNAL OF PHARMACEUTICAL SCIENCES94(8)pp. 1850-1860 JOHN WILEY & SONS INC
B Leone, MR Halse, JH Strange, AR Lonergan, PJ McDonald, E Smith (1994)Ingress of water into zeolite 4A powder plugs., In: Magn Reson Imaging12(2)pp. 247-248

One dimensional profiles of the concentration of water absorbed from vapour diffusing into compacted type 4A zeolite powder have been obtained by broadline NMR imaging. After an induction period of approximately 6 h, a region of full hydration advances linearly with time into the zeolite plug. This behaviour is typical of Case II diffusion. A simple numerical simulation gives good agreement with the experimental results.

L Backhouse, M Dias, JP Gorce, K Hadgraft, PJ McDonald, JW Wiechers (2004)GARField magnetic resonance profiling of the ingress of model skin-care product ingredients into human skin in vitro, In: JOURNAL OF PHARMACEUTICAL SCIENCES93(9)pp. 2274-2283 JOHN WILEY & SONS INC
P Ekanayake, PJ McDonald, JL Keddie (2009)An experimental test of the scaling prediction for the spatial distribution of water during the drying of colloidal films, In: EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS166(1)pp. 21-27
Y Holl, JL Keddie, PJ McDonald, WA Winnik (2001)Drying modes of polymer colloids, In: ACS Symposium Series790pp. 2-26

This chapter reviews the complex step of drying in the latex film formation process. Drying modes have a profound effect on drying rates and on the final properties of films, primarily through their influence on film morphology and the distribution of water-soluble species. Three distinct drying modes (acting separately, successively or together) can be defined, namely homogeneous drying (in which the water concentration remains uniform in the sample throughout the drying process), drying normal to the surface (where a dry layer of increasing thickness develops from the air surface of the latex coating); and lateral drying (where dry areas increase in size in a direction parallel to the substrate). Details are given on the current knowledge and understanding of these drying modes. The last section of the chapter considers the main parameters controlling the drying modes, i.e. thickness and geometric effects, the structure and rheology of the dispersion, particle viscoelasticity, and the overall rate of water loss.

KL PERRY, PJ MCDONALD, AS CLOUGH (1994)CASE-II DIFFUSION IN THE PVC AND ACETONE SYSTEM, In: MAGNETIC RESONANCE IMAGING12(2)pp. 217-219 PERGAMON-ELSEVIER SCIENCE LTD
G Bennett, JP Gorce, JL Keddie, PJ McDonald, H Berglind (2003)Magnetic resonance profiling studies of the drying of film-forming aqueous dispersions and glue layers, In: MAGNETIC RESONANCE IMAGING21(3-4)pp. 235-241 ELSEVIER SCIENCE INC
U Goerke, AHL Chamberlain, EA Crilly, PJ McDonald (2000)Model for water transport into powdered xanthan combining gel swelling and vapor diffusion, In: PHYSICAL REVIEW E62(4)pp. 5353-5359 AMERICAN PHYSICAL SOC
PJ McDonald (1996)The application of broad line MRI to the study of porous media, In: MAGNETIC RESONANCE IMAGING14(7-8)pp. 807-810 PERGAMON-ELSEVIER SCIENCE LTD
Robin Adey-Johnson, J Paul Mclean, Jan Van den Bulcke, Joris Van Acker, Peter J. McDonald (2019)Micro-CT measurements of within-ring variability in the longitudinal hydraulic pathways in Norway spruce, In: IAWA JOURNAL Brill Academic Publishers

This study aimed to define the variability in the microstructure of Norway spruce within an annual ring by examining differences between earlywood and latewood. In particular we were interested in obtaining new information on bordered pit occurrence and locations relative to tracheid ends, plus the lumina dimensions and longitudinal overlap of tracheids that collectively define the longitudinal hydraulic pathways. A stacked series of X-ray micro-CT scans of an annual ring of Norway spruce were made and stitched together longitudinally to form a three-dimensional volume. The imaging resolution was carefully chosen to capture both longitudinal and transverse anatomical details. Measurements of tracheid length; overlap; radial lumen diameter and bordered pit location were made semi-automatically using image analysis. The distribution of radial lumen diameter was used to define earlywood and latewood. Then bordered pit linear density and spatial distribution, tracheid length and overlap were analysed, presented and contrasted for earlywood and latewood. Further differences between earlywood and latewood were found only in bordered pit linear density. Clear trends in radial lumen diameter and pit linear density were observed with radial position within the growth ring. These results provide new information on the variability of the Norway spruce microstructure within an annual ring.

PJ McDonald, S Stapf, P Fantazzini, V Bortolotti, J Mitchell (2013)Proceedings of the 11th International Bologna Conference on Magnetic Resonance in Porous Media (MRPM11), In: MICROPOROUS AND MESOPOROUS MATERIALS178pp. 1-2 ELSEVIER SCIENCE BV
M Zalzale, M Ramaioli, KL Scrivener, PJ McDonald (2016)Gray free-energy multiphase lattice Boltzmann model with effective transport and wetting properties, In: Physical Review E: Statistical, Nonlinear, and Soft Matter Physics94(5)

The paper shows that it is possible to combine the free energy lattice Boltzmann approach to multi-phase modelling of fluids involving both liquid and vapour with the partial bounce back lattice Boltzmann approach to modelling effective media. Effective media models are designed to mimic the properties of porous materials with porosity much finer than the scale of the simulation lattice. In the partial bounce back approach, an effective media parameter or bounce back fraction controls fluid transport. In the combined model, a wetting potential is additionally introduced that controls the wetting properties of the fluid with respect to interfaces between free space (white nodes), effective media (grey nodes) and solids (black nodes). The use of the wetting potential combined with the bounce back parameter gives the model the ability to simulate transport and sorption of a wide range of fluid / material systems. Results for phase separation, permeability, contact angle and wicking in grey media are shown. Sorption is explored in small sections of model multi-scale porous systems to demonstrate two-step desorption, sorption hysteresis and the ink-bottle effect.