The investigation of mechanisms in environmental catalysis using time-resolved methods

The formation of nitrogen oxides (NOx) during a combustion process is difficult to avoid because of the large exotherm and the consequent problem of avoiding local high-temperature spikes. Consequently, for many applications, such as for automotive power generation, there will be a continuing need to use catalytic after-treatment to reduce harmful emissions. The investigation of the mechanisms of the key catalytic reactions in environmental catalysis can provide an insight into the action of the catalyst, and time-resolved methods offer a powerful means to study these processes under realistic conditions. The use of Temporal Analysis of Products (TAP) and Steady State Isotopic Transient Kinetic Analysis (SSITKA) methods to investigate the reduction of NOx under various experimental conditions is described. From a detailed analysis of the SSITKA profiles, it is shown that at low temperatures the mechanism for the formation of N-2 and N2O from NO may differ from the conventional high-temperature mechanism. This is supported by density functional theory calculations, which show that the barrier to the formation of N2O from the reaction of N(ads) and NO(ads) may be too high to allow this process to occur at low temperatures. The alternative reaction of NO(ads) + NO(ads) = N2O(g) + O(ads) is shown to be much more favorable and is consistent with the SSITKA analysis. The remarkable effect of hydrogen as a reductant at low temperatures is described, and alternative interpretations of the role of hydrogen are discussed.

Analysing orchestrations with risk profiles and angel-daemon games

In this paper game theory is used to analyse the effect of a number of service failures during the execution of a grid orchestration. A service failure may be catastrophic in that it causes an entire orchestration to fail. Alternatively, a grid manager may utilise alternative services in the case of failure, allowing an orchestration to recover, A risk profile provides a means of modelling situations in a way that is neither overly optimistic nor overly pessimistic. Risk profiles are analysed using angel and daemon games. A risk profile can be assigned a valuation through an analysis of the structure of its associated Nash equilibria. Some structural properties of valuation functions, that show their validity as a measure for risk, are given. Two main cases are considered, the assessment of Orc expressions and the arrangement of a meeting using reputations.

Changing Attitudes of Community Through the Design Charrette Process

The traditional planning process in the UK and elsewhere takes too long to develop, are demanding on resources that are scarce and most times tend to be unrelated to the needs and demands of society. It segregates the plan making from the decision making process with the consultants planning, the politicians deciding and the community receiving without being integrated into the planning and decision making process. The Scottish Planning system is undergoing radical changes as evidenced by the publication of the Planning Advice Note, PAN by the Scottish Executive in July 2006 with the aim of enabling Community Engagement that allow for openness and accountability in the decision making process. The Public Engagement is a process that is driven by the physical, social and economic systems research aimed at improving the process at the level of community through problem solving and of the city region through strategic planning. There are several methods available to engage the community in large scale projects. The two well known ones are the Enquiry be Design and the Charrette approaches used in the UK and US respectively. This paper is an independent and rigorous analysis of the Charrette process as observed in the proposed Tornagrain Settlement in the Highlands area of Scotland. It attempts to gauge and analyse the attitudes, perceptions of the participants the Charrette as well as the mechanics and structure of the Charrette. The study analyzes the Charrette approach as a method future public engagement in and its effectiveness within the Scottish Planning System in view of PAN 2005. The analysis revealed that the Charrette as a method of engagement could be effective in changing attitudes of the community to the design process under certain conditions as discussed in the paper.

Extending BPM Environments of Your Choice with Performance Related Decision Support

What-if Simulations have been identified as one solution for business performance related decision support. Such support is especially useful in cases where it can be automatically generated out of Business Process Management (BPM) Environments from the existing business process models and performance parameters monitored from the executed business process instances. Currently, some of the available BPM Environments offer basic-level performance prediction capabilities. However, these functionalities are normally too limited to be generally useful for performance related decision support at business process level. In this paper, an approach is presented which allows the non-intrusive integration of sophisticated tooling for what-if simulations, analytic performance prediction tools process optimizations or a combination Of Such solutions into already existing BPM environments. The approach abstracts from process modelling techniques which enable automatic decision support spanning processes across numerous BPM Environments. For instance, this enables end-to-end decision support for composite processes modelled with the Business Process Modelling Notation (BPMN) on top of existing Enterprise Resource Planning (ERP) processes modelled with proprietary languages.

“Hegemony Protected by the Armour of Coercion”: Dashiell Hammett’s Red Harvest and the State

This article argues that Dashiell Hammett's 1929 novel Red Harvest is best understood in the context of the consolidation and expansion of the US state following the First World War and the Russian Revolution. It also argues that Hammett's novel constitutes a highly significant articulation of theoretical debates about the nature of political authority and state power in the modern era and speaks about the transition of one state formation to another. Insofar as Red Harvest explores the way in which the state's coercive and ethical character are bound up together, this article argues that Hammett's novel draws upon an understanding of political authority and state power primarily derived from Gramsci, via Marx. Gramsci insists that control cannot be maintained through force alone (and his conception of hegemony, in turn, suggests a power bloc that can become fragmented and disunited in a war of position). In the same way, Red Harvest traces the transformation of the “economic-corporate” state into the expanded or “ethical” State but crucially any ethical dimension, as Gramsci notes, is always beholden to the needs of the capitalist economy. As such, the apparently arbitrary bloodshed in the novel is conceived as a relatively minor realignment in the ranks of the capitalist classes – certainly less serious than the miners' strike that prefigures the novel. What makes this realignment significant is that it calls attention to the state both as repressive and as a site of conflict and compromise. Here, the work performed by the Continental Op and by the crime novel in general – simultaneously buttressing and, to some extent, contesting the power of the state – needs to be understood as part of the process by which the state is consistently enacting hegemony (albeit protected by the armour of coercion). The article concludes by pointing out that while Gramsci is perhaps too willing to dwell upon the state's expanded reach, Red Harvest is more interested in examining possible “cracks and fissures” in the state formation, even if the critique it ultimately offers goes nowhere and yields nothing.

Nitric oxide and hypoxia

NO (nitric oxide) can affect mitochondrial function by interacting with the cytochrome c oxidase (complex IV) of the electron transport chain in a manner that is reversible and in competition with oxygen. Concentrations of NO too low to inhibit respiration can trigger cell defence response mechanisms involving reactive oxygen species and various signalling molecules such as nuclear factor kappa B and AMP kinase. Inhibition of mitochondrial respiration by NO at low oxygen concentrations can cause so-called metabolic hypoxia and divert oxygen towards other oxygen-dependent systems. Such a diversion reactivates prolyl hydroxylases and thus accounts for the prevention by NO of the stabilization of hypoxia-inducible transcription factor. In certain circumstances NO interacts with superoxide radical to form peroxynitrite, which can affect the action of key enzymes, such as mitochondrial complex I, by S-nitrosation. This chapter discusses the physiological and pathophysiological implications of the interactions of NO with the cytochrome c oxidase.

Multi component coupling reactions of N-acetyl-2-azetine

N-Acetyl-2-azetine undergoes Lewis acid catalysed formal [4+2]-cycloaddition with imines derived from aromatic amines to initially give an approximately 1: 1 mixture of exo-endo-diastereoisomeric 1-(2a,3,4,8b-tetrahydro-2H-1,4-diaza-cyclobuta[a]naphthalen-1-yl)-ethanone cycloadducts which were detected by proton NMR spectroscopy. These products, which were too unstable to isolate, and characterise, reacted further with aromatic amines to give 2,3,4-trisubstituted tetrahydroquinolines in good to excellent yield, predominantly as a single diastereoisomer, with the minor diastereoisomer converting to the major diastereoisomer on silica. The cycloaddition was irreversible and a mechanism is presented for the formation of the major diastereoisomer from the mixture of diastereoisomeric intermediates. A range of conditions is described for converting the 2,3,4-trisubsitituted tetrahydroquinolines into 2,3-disubstituted quinolines.

The death of massive stars - I. Observational constraints on the progenitors of Type II-P supernovae

We present the results of a 10.5-yr, volume-limited (28-Mpc) search for supernova (SN) progenitor stars. In doing so we compile all SNe discovered within this volume (132, of which 27 per cent are Type Ia) and determine the relative rates of each subtype from literature studies. The core-collapse SNe break down into 59 per cent II-P and 29 per cent Ib/c, with the remainder being IIb (5 per cent), IIn (4 per cent) and II-L (3 per cent). There have been 20 II-P SNe with high-quality optical or near-infrared pre-explosion images that allow a meaningful search for the progenitor stars. In five cases they are clearly red supergiants, one case is unconstrained, two fall on compact coeval star clusters and the other twelve have no progenitor detected. We review and update all the available data for the host galaxies and SN environments (distance, metallicity and extinction) and determine masses and upper mass estimates for these 20 progenitor stars using the STARS stellar evolutionary code and a single consistent homogeneous method. A maximum likelihood calculation suggests that the minimum stellar mass for a Type II-P to form is m(min) = 8.5(-1.5)(+1) M-circle dot and the maximum mass for II-P progenitors is m(max) = 16.5 +/- 1.5 M-circle dot, assuming a Salpeter initial mass function holds for the progenitor population (in the range Gamma = -1.35(-0.7)(+0.3)). The minimum mass is consistent with current estimates for the upper limit to white dwarf progenitor masses, but the maximum mass does not appear consistent with massive star populations in Local Group galaxies. Red supergiants in the Local Group have masses up to 25 M-circle dot and the minimum mass to produce a Wolf-Rayet star in single star evolution (between solar and LMC metallicity) is similarly 25-30 M-circle dot. The reason we have not detected any high-mass red supergiant progenitors above 17 M-circle dot is unclear, but we estimate that it is statistically significant at 2.4 sigma confidence. Two simple reasons for this could be that we have systematically underestimated the progenitor masses due to dust extinction or that stars between 17-25 M-circle dot produce other kinds of SNe which are not II-P. We discuss these possibilities and find that neither provides a satisfactory solution. We term this discrepancy the 'red supergiant problem' and speculate that these stars could have core masses high enough to form black holes and SNe which are too faint to have been detected. We compare the Ni-56 masses ejected in the SNe to the progenitor mass estimates and find that low-luminosity SNe with low Ni-56 production are most likely to arise from explosions of low-mass progenitors near the mass threshold that can produce a core-collapse.

The Exotic Eclipsing Nucleus of the Ring Planetary Nebula SuWt 2

SuWt 2 is a planetary nebula (PN) consisting of a bright ionized thin ring seen nearly edge-on, with much fainter bipolar lobes extending perpendicularly to the ring. It has a bright (12th magnitude) central star, too cool to ionize the PN, which we discovered in the early 1990s to be an eclipsing binary. Although it was anticipated that there would also be an optically faint, hot, ionizing star in the system, a spectrum from the International Ultraviolet Explorer (IUE) did not reveal a UV source. We present extensive ground-based photometry and spectroscopy of the central binary collected over the ensuing two decades, resulting in the determination that the orbital period of the eclipsing pair is 4.9 days, and that it consists of two nearly identical A1 V stars, each of mass ~2.7 M sun. The physical parameters of the A stars, combined with evolutionary tracks, show that both are in the short-lived "blue-hook" evolutionary phase that occurs between the main sequence and the Hertzsprung gap, and that the age of the system is about 520 Myr. One puzzle is that the stars' rotational velocities are different from each other, and considerably slower than synchronous with the orbital period. It is possible that the center-of-mass velocity of the eclipsing pair is varying with time, suggesting that there is an unseen third orbiting body in the system. We propose a scenario in which the system began as a hierarchical triple, consisting of a ~2.9 M sun star orbiting the close pair of A stars. Upon reaching the asymptotic giant branch stage, the primary engulfed the pair into a common envelope, leading to a rapid contraction of the orbit and catastrophic ejection of the envelope into the orbital plane. In this picture, the exposed core of the initial primary is now a white dwarf of ~0.7 M sun, orbiting the eclipsing pair, which has already cooled below the detectability possible by IUE at our derived distance of 2.3 kpc and a reddening of E(B - V) = 0.40. The SuWt 2 system may be destined to perish as a Type Ia supernova.

Threshold effects in the Teaching Space Allocation Problem with Splitting

Universities aim for good “Space Management” so as to use the teaching space efficiently. Part of this task is to assign rooms and time-slots to teaching activities with limited numbers and capacities of lecture theaters, seminar rooms, etc. It is also common that some teaching activities require splitting into multiple events. For example, lectures can be too large to fit in one room or good teaching practice requires that seminars/tutorials are taught in small groups. Then, space management involves decisions on splitting as well as the assignments to rooms and time-slots. These decisions must be made whilst satisfying the pedagogic requirements of the institution and constraints on space resources. The efficiency of such management can be measured by the “utilisation”: the percentage of available seat-hours actually used. In many institutions, the observed utilisation is unacceptably low, and this provides our underlying motivation: to study the factors that affect teaching space utilisation, with the goal of improving it. We give a brief introduction to our work in this area, and then introduce a specific model for splitting. We present experimental results that show threshold phenomena and associated easy-hard-easy patterns of computational difficulty. We discuss why such behaviour is of importance for space management.

Adsorption and photocatalysed destruction of cationic and anionic dyes on mesoporous titania films: Reactions at the air-solid interface

Cationic dyes, such as methylene blue (MB), Thionine (TH) and Basic Fuschin (BF), but not anionic dyes, such as Acid Orange 7 (AO7), Acid Blue 9 (AB9) and Acid Fuschin (AF), are readily adsorbed onto mesoporous titania films at high pH (pH 11), i.e. well above the pzc of titania (pH 6.5), due to electrostatic forces of attraction and repulsion, respectively. The same anionic dyes, but not the cationic dyes, are readily adsorbed on the same titania films at low pH (pH 3), i.e. well below titania's pzc. MB appears to adsorb on mesoporous titania films at pH 11 as the trimer (lambda(max) = 570 nm) but, upon drying, although the trimer still dominates, there is an absorption peak at 665 nm, especially notable at low [MB], which may be due to the monomer, but more likely MB J-aggregates. In contrast, the absorption spectrum of AO7 adsorbed onto the mesoporous titania film at low pH is very similar to the dye monomer. For both MB and AO7 the kinetics of adsorption are first order and yield high rate constants (3.71 and 1.481 g(-1) min(-1)), indicative of a strong adsorption process. Indeed, both MB and AO7 stained films retained much of their colour when left overnight in dye-free pH 11 and 3 solutions, respectively, indicating the strong nature of the adsorption. The kinetics of the photocatalytic bleaching of the MB-titania films at high pH are complex and not well-described by the Julson-Ollis kinetic model [A.J. Julson, D.F. Ollis, Appl. Catal. B. 65 (2006) 315]. Instead, there appears to be an initial fast but not simple demethylation step, followed by a zero-order bleaching and further demethylation steps. In contrast, the kinetics of photocatalytic bleaching of the AO7-titania film give a good fit to the Julson-Ollis kinetic model, yielding values for the various fitting parameters not too dissimilar to those reported for AO7 adsorbed on P25 titania powder. (C) 2008 Elsevier B.V. All rights reserved.

Children’s Reasoning About the Temporal Order of Past and Future Events

Four- and five-year-olds completed two sets of tasks that involved reasoning about the temporal order in which events had occurred in the past or were to occur in the future. Four-year-olds succeeded on the tasks that involved reasoning about the order of past events but not those that involved reasoning about the order of future events, whereas 5-year-olds passed both types of tasks. Individual children who failed the past-event tasks were not particularly likely to fail the more difficult future-event tasks. However, children's performance on the reasoning tasks was predictive of their performance on a task assessing their comprehension of the terms “before” and “after.” Our results suggest that there may be a developmental change over this age range in the ability to flexibly represent and reason about the before-and-after relationships between events.

High-precision transit observations of the exoplanet WASP-13b with the RISE instrument

WASP-13b is a sub-Jupiter mass exoplanet orbiting a G1V type star with a period of 4.35 d.The current uncertainty in its impact parameter (0 < b < 0.46) results in poorly definedstellar and planetary radii. To better constrain the impact parameter, we have obtained highprecisiontransit observations with the rapid imager to search for exoplanets (RISE) instrumentmounted on 2.0-m Liverpool Telescope. We present four new transits which are fitted witha Markov chain Monte Carlo routine to derive accurate system parameters. We found anorbital inclination of 85. ◦ 2 ± 0. ◦ 3 resulting in stellar and planetary radii of 1.56 ± 0.04 Rand 1.39 ± 0.05RJup, respectively. This suggests that the host star has evolved off the mainsequence and is in the hydrogen-shell-burning phase.We also discuss how the limb darkeningaffects the derived system parameters.With a density of 0.17ρJ,WASP-13b joins the group oflow-density planets whose radii are too large to be explained by standard irradiation models.We derive a new ephemeris for the system, T0 = 245 5575.5136 ± 0.0016 (HJD) and P =4.353 011 ± 0.000 013 d. The planet equilibrium temperature (Tequ = 1500 K) and the brighthost star (V = 10.4mag) make it a good candidate for follow-up atmospheric studies.

A study of new photocatalyst indicator inks

This article reports the behaviour of three photocatalyst indicator inks, based on the redox dyes: methylene blue (NIB), resorufin (Rf) and 2,6-dichloroindophenol (DCIP), and assess their performance in comparison to the pioneering resazurin (Rz)-based ink for the rapid assessment of the activity of very thin, photocatalyst films, such as Activ (TM) self-cleaning glass. From a commercial 'demonstrator of photocatalysis' perspective, all three redox dyes appear more attractive compared to Rz since all generate colourless products in the ink formulation when photoreduced on Activ (TM) under anaerobic conditions, whereas, the reduced product from Rz, the redox dye resorufin, Rf. is pink in colour. However, the ink based on Rf is far too slow to effect the rapid measurement of photocatalytic activity even in the absence of oxygen, and in the presence of oxygen the latter inhibits the overall kinetics of photoreduction by re-oxidising the reduced product, dihydroresorufin, HRf, back to Rf. Similarly, despite the attractive rapid rate of photobleaching for NIB under anaerobic conditions, compared to the other redox dyes, the reduced product of the MB-based ink. leuco-MB, is so oxygen-sensitive that the ink cannot be photoreduced under aerobic conditions, thus rendering the ink unsuitable for use in the field. The DCIP-based ink is slightly less easy to photoreduce under both anaerobic and ambient atmospheric conditions compared to the Rz-based ink. However. in addition to its more attractive colour change, the DCIP-based ink is unaffected by the ambient level of oxygen present (%O-2) and the relative humidity (%RH), whereas, for the Rz-based ink, both parameters effect the photoreduction kinetics. By incorporating the DCIP ink into a felt-tipped pen, the ink is suitable for use in the laboratory and field to perform not only a qualitative test, but also to allow a semi-quantitative analysis of photocatalytic activity by eye. (C) 2007 Elsevier B.V. All rights reserved.

The effect of construction pattern and unit interlock on the structural behaviour of block pavements

The maintenance or even replacement of cracked pavements requires considerable financial resources and puts a large burden on the budgets of local councils. In addition to these costs, local councils also face liability claims arising from uneven or cracked pedestrian pavements. These currently cost the Manchester City Council and Preston City Council around £6 million a year each. Design procedures are empirical. A better understanding of the interaction between paving blocks, bedding sand and subbase was necessary in order to determine the mode of failure of pavements under load. Increasing applied stress was found to mobilise ‘‘rotational interlock’’, providing increased pavement stiffness and thus increased load dissipation resulting in lower transmitted stress on the subgrade. The indications from the literature
review were that pavements are designed to fail by excessive deformation and that paving blocks remained uncracked at failure. This was confirmed with experimental data which was obtained from tests on segments of pavements that were laid/constructed in a purpose built test frame in the laboratory.