A5101579619- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- X-ray Diffraction in Crystallography
- Physics of Superconductivity and Magnetism
- nanoparticles nucleation surface interactions
- Analytical Chemistry and Chromatography
- Semiconductor Quantum Structures and Devices
- Drug Solubulity and Delivery Systems
- Superconducting Materials and Applications
- Enzyme Structure and Function
- Inhalation and Respiratory Drug Delivery
- Particle accelerators and beam dynamics
- Chemical Thermodynamics and Molecular Structure
- Advanced Chemical Physics Studies
- Semiconductor materials and interfaces
- Silicon Nanostructures and Photoluminescence
- Thermal and Kinetic Analysis
- Catalytic Processes in Materials Science
- Phase Equilibria and Thermodynamics
- Calcium Carbonate Crystallization and Inhibition
- Semiconductor materials and devices
- Solidification and crystal growth phenomena
- Material Dynamics and Properties
- Superconducting and THz Device Technology
- Nuclear Physics and Applications
University of Leeds
2015-2024
Engineering and Physical Sciences Research Council
2021
North Carolina State University
2017-2019
University of Alabama
2019
National Bureau of Economic Research
2017-2019
University of Strathclyde
2019
NHS Digital
2018
Centre for Process Innovation
2016
University of Surrey
2016
International Union of Pure and Applied Chemistry
2014
The conductance of Au-doped Si single crystals was measured during irradiation with 30-nsec $Q$-switched ruby-laser pulses at energy densities above the melting threshold (\ensuremath{\sim}0.9 J/${\mathrm{cm}}^{2}$). sample is determined primarily by thickness molten layer so that solid-liquid interface velocity can be found from current transient. crystallization to 2.7\ifmmode\pm\else\textpm\fi{}0.1 m/sec, in close agreement calculated values based on a heat-flow model.
There has been much recent interest in the role of solution chemistry and particular importance molecular self-assembly nucleation crystalline phases. Techniques such as FTIR NMR have highlighted existence solution-phase dimers which many cases mirror structural synthons found resulting macroscopic crystals. However, there are no reported examples this new insight into phase linked directly to kinetics crystal nucleation. Here for first time, using a combination FTIR, computational...
We have performed intra- and extra-cavity microwave frequency (1–100 GHz) measurements on high quality Y1Ba2Cu3O7−x superconducting thin films (100) LaAlO3 substrates. The ∼0.3 μm fabricated by the pulsed laser deposition technique exhibit transition temperatures >90 K, as determined resistivity ac susceptibility measurements, critical current densities of 5×106 A/cm2 at 77 K. Moreover, ion beam channeling minimum yields ∼3% were measured, indicating extremely crystalline grown...
The accomplishments and the prospects of forming A15 superconductors using electron beam evaporation are reviewed. techniques monitoring controlling discussed. special advantages to synthesis materials pointed out, followed by a number examples. prospect large scale production processing is also considered.
High-field cross-polarisation magic-angle spinning 13C NMR spectra are presented for the four known polymorphs of anhydrous carbamazepine, a dihydrate, and two solvates. These all distinctive, despite relatively low spectral dispersion, give immediate information about crystallographic asymmetric unit. The results trigonal monoclinic forms consistent with published crystal structures. That triclinic form was found to contain molecules in unit, which has recently been confirmed by an X-ray...
O bjectives : The overall aim of this study was to examine the nature relationship between dog‐ownership and canine obesity, explored in two cohorts overweight/obese or non‐overweight dogs (n=125). This paper concentrates on owners’ perception dog weight. M ethods A researcher‐mediated questionnaire used collect data from owners attending a small veterinary practice. Interviewees (n=121) were asked qualitative quantitative questions, designed views their with dogs. R esults Although high...
A framework for conceptualization of scalable solution-crystallization processes cocrystals is developed and demonstrated using carbamazepine-nicotinamide as the model system. Calculation intermolecular interactions crystal lattice energy were carried out to understand structure strength binding synthons well predict likely growth morphology overall rate at scale. Experimental measurements solubility behavior pure components, solid form stability domain, speciation in solution effects on...
Detailed measurements and line-shape fits of the combined LO- TO-phonon assisted electron-hole condensate luminescence lines from laser-excited, high-purity Si are reported in temperature range 2.2 to 13.0\ifmmode^\circ\else\textdegree\fi{}K. These data permit a determination liquid density $n$, chemical potential $\ensuremath{\mu}$, Fermi energy ${E}_{F}$, work function $\ensuremath{\varphi}$, as functions temperature. Fitting these ${T}^{2}$ dependence expected Fermi-liquid theory gives...
The growth rates of the {001} and {011} crystal faces ibuprofen were measured as a function solution crystallisation environment from which likely interfacial kinetic mechanisms characterised.
The key intermolecular (synthonic) interactions, crystal morphology, and surface interfacial stability of the anti-inflammatory drug RS-ibuprofen are examined in relation to its bulk chemistry, rationalize growth behavior as a function crystallization environment. OH···O H-bonding dimers between adjacent carboxylic acid groups calculated be strongest (intrinsic) synthons, with other important synthons arising due interactions less-polar phenyl ring aliphatic chain. Morphological prediction,...
When determining crystal structures of organic molecular materials from high-resolution powder diffraction data, the key step is generation reliable trial for final refinement. The subject study reported here pharmaceutical material anhydrous theophylline (3,7-dihydro-1,3-dimethyl-1H-purine-2,6-dione), which contains both oxygen and nitrogen as possible hydrogen bond acceptor atoms. A systematic search direct space was employed to assess every packing arrangement asymmetric unit within...
Conditions required for in situ growth of YBaCuO thin films by reactive electron-beam evaporation have been explored. Three sources activated oxygen (atomic from microwave discharge, plasma generated electron beams, and an ion beam) were compared. The best results so far obtained with atomic oxygen. Epitaxial high critical currents grown on SrTiO/sub 3/ [100] [110], Al/sub 2/O/sub (1102), MgO at 600 degrees C. Evaporation rates controlled a rate monitor using absorption.< <ETX...
A recently developed method (Hammond et al., 2006) for estimating solution binding at crystal habit surfaces and hence interfacial tension is extended to calculations of solution-effected attachment energies the prediction solvent-mediated morphology. The validated through examination morphology aspirin crystallized from aqueous ethanolic solutions. influence supersaturation on resultant also discussed with reference differing intermolecular packing this material's different surfaces....
The molecular assembly and subsequent nucleation of para-amino benzoic acid (PABA) from ethanolic solutions is probed using a multi-scale multi-technique approach. This applied by examining interrelating information regarding the molecular, solution-state, cluster, solid-state surface structures to understand why alpha form PABA crystallised in preference its low temperature beta form. Calculations suggest that conformational changes within solute molecule play little or no role directing...
The synthonic modeling approach provides a molecule-centered understanding of the surface properties crystals. It has been applied extensively to understand crystallization processes. This study aimed investigate functional relevance formulation inhalation powders by assessing cohesivity three active pharmaceutical ingredients (APIs, fluticasone propionate (FP), budesonide (Bud), and salbutamol base (SB)) commonly used excipient, α-lactose monohydrate (LMH). is found that FP (−11.5 kcal/mol)...
A polythermal methodology to assess the mechanisms and kinetics of solution crystallisation is described used in connection with a recently proposed model for dependence critical undercooling on cooling rate (D. Kashchiev, A. Borissova, R. B. Hammond, K. J. Roberts, Cryst. Growth, 312 (2010) 698–704; Phys. Chem. B, 114 5441–5446). This first principles allows determination parameters that could otherwise only be obtained by combined application both isothermal methods. The validated through...
A workflow for tailor-made additive screening and crystallization control using a combination of molecular modeling experimental techniques is presented. The impact seven structurally analogous additives, the majority which contain carboxylic acid group, on nucleation α-para-aminobenzoic assessed. Intermolecular grid search used to determine dimer interaction energies. Of these, three additives are found form stronger group interactions with compound. Solvation energy calculations...
Classical homogeneous nucleation theory has been integrated with molecular modeling techniques to model the effects of cluster shape-anisotropy associated from solution. In this approach, geometric shape a crystal nucleus is modeled assuming it equates predicted growth morphology resultant macroscopic later simulated via an attachment energy using empirical intermolecular force calculations adopting atom−atom approximation. A new coupled integrating theory, morphological simulation and...
Crystallization in solutions under steady cooling is considered the case of instantaneous nucleation, which all crystallites appear at once solution and grow absence born subsequently. Expressions are obtained for total crystallite volume as a function steadily increasing undercooling. These expressions employed determining dependence relative critical undercooling uc crystallization on rate q. The resulting uc(q) formula reveals physical meaning parameters linear relationship, often...
Low-salinity water flooding of formation in rock cores is, potentially, a promising technique for enhanced oil recovery (EOR), but details the underlying mechanisms remain unclear. The salinity effect on interface between and was investigated here using molecular dynamics (MD) simulation method. n-Decane selected as representative component, SPC/E all-atom optimized potentials liquid simulations (OPLS-AA) force fields were used to describe water/oil/ionic interactions saltwater n-decane...