DaviD chesney - Academia.edu (original) (raw)

Papers by DaviD chesney

Analytica Chimica Acta, 1999

Journal of Chromatography A, 1991

Analytical Chemistry, 1992

SupercrHlcal fluld extractlon wlth carbon dloxlde has been found to be Mecthre for the Watlon of ... more SupercrHlcal fluld extractlon wlth carbon dloxlde has been found to be Mecthre for the Watlon of reddue levels (0.1-1 ppm) of 2,ddkhlorophennol hom selected plant tlwes. The 2,4dkhbroph.nol reddue8 were Incompletely extracted wlth wpercrltlcal C02 alone, dnce a substantlal fractlon of the 2,44chlorophend was covalently attached to the plant matrlx. An acld pretreatment procedure was developed to partlally hydrolyze the plant tluue prior to extractlon, re-Ieadng the bound 2,4-dlchlorophenol reddues. Steam dlstlllatlon showed higher reddue Ieveb for fleld-treated straw samples. T)lb k atlrlbuted to the greater degree of hyfkolysk Inherent h the stem dktllatlon procedure. Supercrttkal C02 extractbn of fldbtreated 8 w d samples showed hlgher levels of 2,4dkhlorophenol redduer than dld steam Wlatkn. The supercrttlcal fluld extractant was able to solvate 2,4dlchbroplwnol reddues In the Interlor of the seed and trawmrl themtothesurfaceforcdkctlon. Theaqu8o"edkmwed In steam dtalllatton was unable to penetrate the hydfophoMc seed matrlx to the same degree. WhHe the actual extractlon tbne e x p e r l d In wpercrltkal fluld extraction was far less than that of steam dktlllatlon (45 mln vs 6 h, respectively), the total remple preparatbn tbne was sLnllar In both methods.

Journal of Chemical and Engineering Data, 2006

The binary (solute + CO 2 ) equilibrium solubilities of six substituted phenols (2,5-dimethyl phe... more The binary (solute + CO 2 ) equilibrium solubilities of six substituted phenols (2,5-dimethyl phenol, 2,3-dimethyl phenol, 2,4,6-trimethyl phenol, 2,3,5-trimethyl phenol, 4-phenyl phenol, and 4-tert-butyl phenol) were determined at a temperature of 308 K in the pressure range of 10.1 to 28.0 MPa. Solubility data were obtained using a dynamic approach with a simple and reliable apparatus. The mole fraction solubilities of substituted phenols ranged from 5.14 × 10 -5 to 2.56 × 10 -2 . Solubilities of three ternary (two solutes + CO 2 ) systems were investigated at a temperature of 308 K in the pressure range of 10.1 to 28.0 MPa. In the 4-phenyl phenol + 2,3,5-trimethyl phenol and 4-phenyl phenol + 2,4,6-trimethyl phenol systems, the solubility of 4-phenyl phenol was enhanced relative to its binary solubility by 22.9 % and 217 %, respectively. The 2,3,5-trimethyl phenol and 2,4,6-trimethyl phenol did not exhibit any solubility enhancements in the two ternary systems. Accurate solubilities could not be measured for the 2,5-dimethyl phenol + 4-tert-butyl phenol ternary system due to the existence of a liquid phase under the conditions studied.

Separation Science and Technology, 2011

The commercial value of phenols is often reduced due to the presence of colored impurities. Sever... more The commercial value of phenols is often reduced due to the presence of colored impurities. Several conventional techniques have been used for the purification of phenols. However, conventional purification techniques are tedious and make use of hazardous and expensive organic solvents. In this study, we present a new method for purification of an aged-discolored (orange) commercial 2,3-dimethyl phenol (2,3-DMP) reagent (97%) using supercritical fluid CO2 (SCF CO2), as an extraction solvent. A supercritical fluid extraction (SFE)/purification apparatus was constructed and purification of the reagent under different extraction conditions was investigated. Based on the differential solubility of the 2,3-DMP and the impurities in SCF CO2, the commercial reagent was successfully purified by SFE; the purified 2,3-DMP was a white solid of high purity (>99.5%). The SFE method was also applied to purify a recently purchased batch of 2,3-DMP reagent. We found that the reagent purified by SFE was of a higher quality than a commercially available analytical standard.

Journal of Chemical and Engineering Data, 2008

ABSTRACT The equilibrium solubilities of benzoic acid (BA), salicylic acid (SAL), and acetylsalic... more ABSTRACT The equilibrium solubilities of benzoic acid (BA), salicylic acid (SAL), and acetylsalicylic acid (ASA) were determined in binary (solute + CO2), ternary (two solutes + CO2), and quaternary systems (three solutes + CO2) at temperatures ranging from (308 to 328) K and pressures ranging from (10.1 to 28.0) MPa. Solubility data were obtained using a dynamic approach with a simple and reliable apparatus. Polar mixed-solid solute systems demonstrated solubility enhancements, which were consistent with the entrainer effect. In all the polar ternary systems studied, at least one component exhibited solubility enhancements. In the polar quaternary system studied, the solubility of each component increased in comparison to each binary system; the solubility of ASA, SAL, and BA was enhanced up to 484 %, 248 %, and 43 %, respectively. The high solubility enhancements observed in our study indicate that solute–solute interactions are significant in the supercritical fluid (SCF) phase. The solubility enhancements observed in the polar mixed-solid solute systems studied resulted in a decrease in selectivity of SCF CO2. However, in a quaternary system consisting of BA, SAL, and fluoranthene (FLU), the selectivity of SCF CO2 for SAL versus FLU increased by a factor of 2.7 due to specific solute–solute interactions. This study showed that solute−solute interactions in mixed solid solute systems can result in an increase in the solubility of solutes and also the selectivity of SCF CO2.

International Journal of Healthcare Technology and Management, 2009

... Kay Penny Centre of Mathematics, Napier University Craiglockhart Campus, Edinburgh, EH14 1DJ,... more ... Kay Penny Centre of Mathematics, Napier University Craiglockhart Campus, Edinburgh, EH14 1DJ, UK Email: k.penny@napier.ac.uk Peter Oakley ... Kay Penny is a lecturer in statistics at Napier University in Edinburgh, Scotland. ...

We assessed whether there is a recognisable pattern of facial morphology in photographs of a seri... more We assessed whether there is a recognisable pattern of facial morphology in photographs of a series of 62 children with idiopathic congenital talipes equinovarus (CTEV). Photographs were scored for a number of facial characteristics by a research team comprising orthopaedic surgeons and clinical geneticists, to identify a subgroup of children with idiopathic CTEV, who shared characteristic facial features. Seven children were identified as having a "CTEV face". There was good correlation between the "CTEV face" and the individual facial features. Repeatability of the assessment was good, and there was good correlation between the geneticists and the orthopaedic surgeons, suggesting that no special training in dysmorphology is required to identify the "CTEV face". There is a subgroup of children with idiopathic CTEV who can be reliably identified by their facial characteristics. The significance of this finding is unclear but it may be of use in clinical genetic studies, and studies of the aetiology of CTEV.

Worldwide, 1-4 per 1,000 births are affected by clubfoot. Clubfoot etiology is unclear, but both ... more Worldwide, 1-4 per 1,000 births are affected by clubfoot. Clubfoot etiology is unclear, but both genetic and environmental factors are thought to be involved. Low folate status in pregnant women has been implicated in several congenital malformations, and folate metabolism may be affected by polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR). Using a case-parent-triad design, the authors investigated whether the MTHFR C677T polymorphism, and maternal periconceptional folic acid supplement use, influenced risk of isolated clubfoot. Three hundred seventy-five United Kingdom case-parent triads were recruited in 1998-1999. Among the children, there was a significant trend of decreasing clubfoot risk with increasing number of T alleles: relative risk for CT vs. CC ¼ 0.75, 95% confidence interval: 0.57, 0.97; relative risk for TT vs. CC ¼ 0.57, 95% confidence interval: 0.35, 0.91; p trend ¼ 0.006. This association was not modified by maternal folic acid use. Maternal MTHFR genotype did not influence clubfoot risk for the offspring overall, although a possible interaction with folic acid use was found. This is the first known report of a specific genetic polymorphism associated with clubfoot. The direction of the association is intriguing and suggests that DNA synthesis may be relevant in clubfoot development. However, clubfoot mechanisms are poorly understood, and the folate metabolism pathway is complex. Further research is needed to elucidate these relations.

BMC Musculoskeletal Disorders, 2007

Background Outcome following management of congenital talipes equinovarus (clubfoot) can be asses... more Background Outcome following management of congenital talipes equinovarus (clubfoot) can be assessed in a number of ways. Bjonness stated simply that "the patient is the final judge of whether he has a good foot"; a purely subjective assessment. Others have employed objective measures. Combining subjective evaluation with a more objective assessment of movement and position of the foot, is likely to give a more comprehensive picture of the final result of clubfoot. The purpose of this study was to compare subjective and objective outcome following management of clubfoot, and evaluate sex differences in outcome. Methods We used a patient-administered subjective assessment of outcome following treatment of clubfoot and compared it with objective anthropometry and range of movement of the ankle to assess and compare subjective and objective outcome in clubfoot. Statistical analysis was performed using Pearson correlation coefficients. Significance was tested using Student's t-test test. Results Objective outcome can be assessed using length of the foot, calf circumference and range of movement at the ankle. These are easy to measure, reproducible, and correlate well with subjective outcome. Objective outcome is comparable for boys and girls. However, subjectively, female patients and their parents are less happy with the results of management of clubfoot. Conclusion There is a correlation between the anthropometric measures and the subjective outcome and an objective grading can be designed using foot length, calf muscle bulk and range of movement at the ankle.

Trauma audit is intended to develop effective care for injured patients through process and outco... more Trauma audit is intended to develop effective care for injured patients through process and outcome analysis, and dissemination of results. The system records injury details such as the patient's sex and age, the mechanism of the injury, various measures of the severity of the injury, ...

The Space Weather Modeling Framework (SWMF) aims at providing software architecture for integrate... more The Space Weather Modeling Framework (SWMF) aims at providing software architecture for integrated modeling of different domains of Sun-Earth system and high-performance physics-based space weather simulation. The SWMF component architecture promotes collaboration between developers of individual physics models and empowers them by providing coupling context and parallel and distributed computing support. The framework design places minimal requirements on components. The webbased Graphical User Interface facilitates the remote access to the framework even from scientific groups that do not have an access to supercomputers or clusters otherwise.

The NASA-funded Space Weather Modeling Framework (SWMF) is developed to provide "plug and play" t... more The NASA-funded Space Weather Modeling Framework (SWMF) is developed to provide "plug and play" type Sun-to-Earth simulation capabilities serving the space physics modeling community. In its fully developed form, the SWMF will comprise a series of interoperating models of physics domains, ranging from the surface of the Sun to the upper atmosphere of the Earth. In its current form the SWMF links together five models: Global Magnetosphere, Inner Heliosphere, Ionosphere Electrodynamics, Upper Atmosphere, and Inner Magnetosphere. The framework permits to switch models of any type. The SWMF is a structured collection of software building blocks that can be used or customized to develop Sun-Earth system modeling components, and to assemble them into application. The SWMF consist of utilities and data structures for creating model components and coupling them. The SWMF contains Control Model, which controls initialization and execution of the components. It is responsible for component registration, processor layout for each component and coupling schedules. A component is created from the user-supplied physics code by adding a wrapper, which provides the control functions and coupling interface to perform the data exchange with other components. Both the wrapper and coupling interface are constructed from the building blocks provided by the framework itself. The current SWMF implementation is based on the latest component technology and uses many important concepts of Object-Oriented Programming emulated in Fortran 90. Currently it works on Linux Beowulf clusters, SGI Origin 2000 and Compaq ES45 machines.

The University of Michigan's Space Weather Modeling Framework (SMWF) aims at providing framework ... more The University of Michigan's Space Weather Modeling Framework (SMWF) aims at providing framework for physics based space weather simulations, as well as for various space physics applications. The SWMF combines numerical models of the Solar Corona, Inner Heliosphere, Solar Energetic Particles, Global Magnetosphere, Inner Magnetosphere, Radiation Belts, Ionosphere and Upper Atmosphere into a parallel, high performance model. We present SWMF results from the October 29, 2003 storm, in which the global magnetosphere (BATSRUS), inner magnetosphere (RCM), ionospheric electrodynamics, and upper atmospheric models (GITM) are run together driven by data from the upstream ACE satellite. We will present comparisons between the simulation results and data from different magnetospheric satellites. We will further present model comparisons between the global magnetosphere run with and without the inner magnetosphere coupling.

Journal of Geophysical Research, 2005

1] The Space Weather Modeling Framework (SWMF) provides a high-performance flexible framework for... more 1] The Space Weather Modeling Framework (SWMF) provides a high-performance flexible framework for physics-based space weather simulations, as well as for various space physics applications. The SWMF integrates numerical models of the Solar Corona, Eruptive Event Generator, Inner Heliosphere, Solar Energetic Particles, Global Magnetosphere, Inner Magnetosphere, Radiation Belt, Ionosphere Electrodynamics, and Upper Atmosphere into a high-performance coupled model. The components can be represented with alternative physics models, and any physically meaningful subset of the components can be used. The components are coupled to the control module via standardized interfaces, and an efficient parallel coupling toolkit is used for the pairwise coupling of the components. The execution and parallel layout of the components is controlled by the SWMF. Both sequential and concurrent execution models are supported. The SWMF enables simulations that were not possible with the individual physics models. Using reasonably high spatial and temporal resolutions in all of the coupled components, the SWMF runs significantly faster than real time on massively parallel supercomputers. This paper presents the design and implementation of the SWMF and some demonstrative tests. Future papers will describe validation (comparison of model results with measurements) and applications to challenging space weather events. The SWMF is publicly available to the scientific community for doing geophysical research. We also intend to expand the SWMF in collaboration with other model developers.

The Space Weather Modeling Framework (SMWF) aims at providing a flexible plug-and-play type frame... more The Space Weather Modeling Framework (SMWF) aims at providing a flexible plug-and-play type framework for physics based space weather simulations, as well as for various space physics applications. The SWMF combines numerical models of the Inner Heliosphere, Solar Energetic Particles, Global Magnetosphere, Inner Magnetosphere, Radiation Belt, Ionosphere and Upper Atmosphere into a parallel, high performance model. All the components can be replaced with alternatives, and one can use only a subset of the components. The components are coupled to the control module via standardized interfaces, and an efficient parallel coupling toolkit is used for the pair-wise coupling of the components. The execution and parallel layout of the components is controlled by SWMF. Both serial and concurrent execution models are supported. With concurrent execution the SWMF can run faster than real time on massively parallel machines. The configuration, compilation and execution of the framework can be done with a user friendly Graphical User Interface. The SWMF enables us to do simulations that were not possible with the individual components. We highlight some numerical simulations obtained with the SWMF. The SWMF has been developed with the support of NASA HPCC, and MURI DoD in the past 2 years.

Poetry is the kind of thing poets write. -Robert Frost Man, if you gotta ask, you'll never know. ... more Poetry is the kind of thing poets write. -Robert Frost Man, if you gotta ask, you'll never know. -Louis Armstrong A POET IS LIMITED in the materials he can use in creating his works: all he has are words to express his ideas and feelings. These words need to be precisely right on several levels at once: