Kinetics of the selective reduction of NO with CH4 over an In-Fe2O3/HZSM-5 catalyst

A kinetic model presented for the selective reduction of NO with CH4 over an InFe2O3/HZSM-5 catalyst by considering the process as a combination of two simultaneous reactions: NO+O2CH4 (reaction 1) and O-2+CH4 (reaction 2). Linear regression calculation was employed to find the kinetic parameters. It was found that although the activation energies of the two reactions were almost identical, the reaction rate constants were dramatically different, namely, k(1)much greater than k(2), indicating that the NO+O-2+CH4 reaction was more preferable to take place on the In-Fe2O3/HZSM-5 catalyst as compared with the O-2+CH4 reaction.

Effects of prior heavy exercise on V(over dot)O-2 kinetics during heavy exercise are related to changes in muscle activity

Burnley, M., Doust, J.H., Ball, D. and Jones, A.M. (2002) Effects of prior heavy exercise on VO2 kinetics during heavy exercise are related to changes in muscle activity. Journal of Applied Physiology 93, 167-174. RAE2008

Influence of blood donation on O-2 uptake on-kinetics, peak O-2 uptake and time to exhaustion during severe-intensity cycle exercise in humans

Thatcher, Rhys, et al., 'Influence of blood donation on O-2 uptake on-kinetics, peak O-2 uptake and time to exhaustion during severe-intensity cycle exercise in humans', Experimental Physiology (2006) 91(3) pp.499-509 RAE2008

Time required for the restoration of normal heavy exercise Vo(2) kinetics following prior heavy exercise

Burnley, M., Doust, J. and Jones, A. (2006). Time required for the restoration of normal heavy exercise Vo(2) kinetics following prior heavy exercise. Journal of Applied Physiology. 101(5), pp.1320-1327 RAE2008

Secondary structure effects on DNA hybridization kinetics: a solution versus surface comparison

The hybridization kinetics for a series of designed 25mer probe�target pairs having varying degrees of secondary structure have been measured by UV absorbance and surface plasmon resonance (SPR) spectroscopy in solution and on the surface, respectively. Kinetic rate constants derived from the resultant data decrease with increasing probe and target secondary structure similarly in both solution and surface environments. Specifically, addition of three intramolecular base pairs in the probe and target structure slow hybridization by a factor of two. For individual strands containing four or more intramolecular base pairs, hybridization cannot be described by a traditional two-state model in solution-phase nor on the surface. Surface hybridization rates are also 20- to 40-fold slower than solution-phase rates for identical sequences and conditions. These quantitative findings may have implications for the design of better biosensors, particularly those using probes with deliberate secondary structure.

Dissolution kinetics of octadecanethiolate monolayers electro-adsorbed on Au(1 1 1)

Monolayers of octadecanethiolate on Au(1 1 1) surface were formed under electrochemical control. The influence of the formation time on the reductive desorption process was studied by cyclic voltammetry and chronoamperometry. When the formation time is increased, the reductive desorption peak observed on the voltammograms is significantly shifted in the negative direction, while the cathodic charge is only slightly affected. This behaviour is attributed to a higher degree of organisation of the monolayers for longer formation times, highlighting the role of defect sites in promoting the dissolution. A good agreement was found between our experimental chronoamperograms and theoretical models describing the dissolution process by a shrinkage mechanism. It is demonstrated that a reorganisation process takes place, consisting in the merging of small condensed domains into larger ones. This annealing phenomenon is time and potential dependent, the largest condensed domains being obtained for the longest formation times and least negative potentials. © 2008 Elsevier B.V. All rights reserved.

Kinetics of anti-Campylobacter jejuni monomeric and polymeric immunoglobulin A1 and A2 responses in serum during acute enteritis.

The intensity and kinetics of the serum polymeric and monomeric immunoglobulin A1 (IgA1) and IgA2 antibody responses to Campylobacter jejuni were analyzed. A rapid and marked serum IgA antibody response involving both the monomeric and polymeric components of IgA was observed after C. jejuni infections. IgA antibodies reached a peak of activity in serum during week 2 after the first symptoms of enteritis, about 10 days before the peak of IgG activity. Polymeric IgA accounted for most of the anti-C. jejuni activity at the peak of the IgA response (median, 90%; range, 44 to 98%) but rapidly disappeared from serum over a few weeks. In contrast, the serum monomeric IgA antibody response was low and was maintained over a prolonged period of time. Anti-C. jejuni IgA detected in the serum of healthy blood donors was mainly monomeric (median, 83%; range, 17 to 94%). In both the patients and the positive controls, IgA1 was the predominant (greater than 85%) subclass involved, even when the IgA antibody response was mainly polymeric. Our results suggest that polymeric IgA antibody responses are linked to a strong or persisting antigenic stimulation or both. Polymeric IgA antibodies appear to be a potential marker of acute C. jejuni infections, and their determination could provide a useful tool for the serological diagnosis of recent C. jejuni infections.

Using fractal downscaling of satellite precipitation products for hydrometeorological applications

The objective of spatial downscaling strategies is to increase the information content of coarse datasets at smaller scales. In the case of quantitative precipitation estimation (QPE) for hydrological applications, the goal is to close the scale gap between the spatial resolution of coarse datasets (e.g., gridded satellite precipitation products at resolution L × L) and the high resolution (l × l; L»l) necessary to capture the spatial features that determine spatial variability of water flows and water stores in the landscape. In essence, the downscaling process consists of weaving subgrid-scale heterogeneity over a desired range of wavelengths in the original field. The defining question is, which properties, statistical and otherwise, of the target field (the known observable at the desired spatial resolution) should be matched, with the caveat that downscaling methods be as a general as possible and therefore ideally without case-specific constraints and/or calibration requirements? Here, the attention is focused on two simple fractal downscaling methods using iterated functions systems (IFS) and fractal Brownian surfaces (FBS) that meet this requirement. The two methods were applied to disaggregate spatially 27 summertime convective storms in the central United States during 2007 at three consecutive times (1800, 2100, and 0000 UTC, thus 81 fields overall) from the Tropical Rainfall Measuring Mission (TRMM) version 6 (V6) 3B42 precipitation product (~25-km grid spacing) to the same resolution as the NCEP stage IV products (~4-km grid spacing). Results from bilinear interpolation are used as the control. A fundamental distinction between IFS and FBS is that the latter implies a distribution of downscaled fields and thus an ensemble solution, whereas the former provides a single solution. The downscaling effectiveness is assessed using fractal measures (the spectral exponent β, fractal dimension D, Hurst coefficient H, and roughness amplitude R) and traditional operational scores statistics scores [false alarm rate (FR), probability of detection (PD), threat score (TS), and Heidke skill score (HSS)], as well as bias and the root-mean-square error (RMSE). The results show that both IFS and FBS fractal interpolation perform well with regard to operational skill scores, and they meet the additional requirement of generating structurally consistent fields. Furthermore, confidence intervals can be directly generated from the FBS ensemble. The results were used to diagnose errors relevant for hydrometeorological applications, in particular a spatial displacement with characteristic length of at least 50 km (2500 km2) in the location of peak rainfall intensities for the cases studied. © 2010 American Meteorological Society.

Radium and barium removal through blending hydraulic fracturing fluids with acid mine drainage.

Wastewaters generated during hydraulic fracturing of the Marcellus Shale typically contain high concentrations of salts, naturally occurring radioactive material (NORM), and metals, such as barium, that pose environmental and public health risks upon inadequate treatment and disposal. In addition, fresh water scarcity in dry regions or during periods of drought could limit shale gas development. This paper explores the possibility of using alternative water sources and their impact on NORM levels through blending acid mine drainage (AMD) effluent with recycled hydraulic fracturing flowback fluids (HFFFs). We conducted a series of laboratory experiments in which the chemistry and NORM of different mix proportions of AMD and HFFF were examined after reacting for 48 h. The experimental data combined with geochemical modeling and X-ray diffraction analysis suggest that several ions, including sulfate, iron, barium, strontium, and a large portion of radium (60-100%), precipitated into newly formed solids composed mainly of Sr barite within the first ∼ 10 h of mixing. The results imply that blending AMD and HFFF could be an effective management practice for both remediation of the high NORM in the Marcellus HFFF wastewater and beneficial utilization of AMD that is currently contaminating waterways in northeastern U.S.A.