Finite element solution of Navier Stokes equations adapted to a priori error estimates

The paper is based on qualitative properties of the solution of the Navier-Stokes equations for incompressible fluid, and on properties of their finite element solution. In problems with corner-like singularities (e.g. on the well-known L-shaped domain) usually some adaptive strategy is used. In this paper we present an alternative approach. For flow problems on domains with corner singularities we use the a priori error estimates and asymptotic expansion of the solution to derive an algorithm for refining the mesh near the corner. It gives very precise solution in a cheap way. We present some numerical results.

An alternative approach to ascertain the rate-determining steps of TiO2 photoelectrocatalytic reaction by electrochemical impedance spectroscopy

In an attempt to ascertain the rate-determining steps (RDS) of TiO2 photoelectrocatalytic (PEC) reaction, the PEC oxidation of sulfosalicylic acid (SSA) solution in a TiO2-coated electrode reactor system was monitored by applying the electrochemical impedance spectroscopy (EIS) method. In the meantime, an EIS mathematical model was first established to theoretically simulate the PEC reaction. Based on the EIS model, the theoretical simulation indicates three typical reactions in a PEC oxidation process, which include the charge-transfer-dominated reaction, both the charge-transfer- and adsorption-dominated reaction, and the adsorption-dominated reaction. The experimental results of EIS measurement showed that there was only one arc/semicircle on the EIS plane display when the external bias applied was below 200 mV (vs SCE) in the SSA PEC degradation whereas there were two arcs/semicircles when the externally applied bias exceeded 200 mV (vs SCE). The experimental results have a good agreement with the model simulation. The EIS method in this study provides an easier way to determine the RDS in a PEC oxidation process, which would be helpful to better control the reaction in practice.

The rebirth of dependence– offering an alternative understanding of the financial crisis

Purpose – This article aims to contribute to the re-evaluation of the global market system using a Marxist inspired theory of development, dependency.

Design/methodology/approach – This article draws on dependency theory as an alternative means of understanding global relationships. Building on existing literature, it modifies dependency to encapsulate technological developments and trends in the global market.

Findings – Re-evaluating the global market and the relationships that underpin it, through an alternative theory, highlights the fragility of markets and associated relationships. Increasingly, nation states are becoming irrelevant. This presents a problem as the main actors in the global market today are “above” inter-state relations, yet the organs that regulate their behaviour still are grounded in inter-state rhetoric. The relationship between development and underdevelopment remains.

Research limitations/implications – The financial crisis has propagated a wealth of interest in the relationships between states, between multi-national corporations (MNCs) and between MNCs and state. Using this broad theory of modified dependency, it can be applied to a range of different relationships. In the wake of financial crisis, there is the opportunity to raise awareness of these ingrained issues and initiate discussions at national, regional and international levels to alleviate some of the conditions of dependence.

Practical implications – Regardless of the work of national governments and NGOs to instigate development in lesser-developed regions through policy and regulations, unless there is a conscientious commitment from MNCs operating in that region to contribute to development, the result will be the development of underdevelopment and the underdevelopment of development. CSR can help alleviate the conditions of the dependence on capital generated by MNCs, but this is not a solution to an ingrained problem, capitalism.

Originality/value – This article introduces a modified theory of dependency for the first time. It applies the theory to the financial crisis and to the continent of Africa. It considers the role that CSR can play in alleviating the conditions of dependence.

Inverse planned constant dose rate volumetric modulated arc therapy (VMAT) as an efficient alternative to five-field intensity modulated radiation therapy (IMRT) for prostate

Purpose: The aim of this work was to determine if volumetric modulated arc therapy (VMAT) plans, created for constant dose-rate (cdrVMAT) delivery are a viable alternative to step and shoot five-field intensity modulated radiation therapy (IMRT). Materials and methods: The cdrVMAT plans, inverse planned on a treatment planning system with no solution to account for couch top or rails, were created for delivery on a linear accelerator with no variable dose rate control system. A series of five-field IMRT and cdrVMAT plans were created using dual partial arcs (gantry rotating between 260° and 100°) with 4° control points for ten prostate patients with the average rectal constraint incrementally increased. Pareto fronts were compared for the planning target volume homogeneity and average rectal dose between the two techniques for each patient. Also investigated were tumour control probability and normal tissue complication probability values for each technique. The delivery parameters [monitor units (MU) and time] and delivery accuracy of the IMRT and VMAT plans were also compared. Results: Pareto fronts showed that the dual partial arc plans were superior to the five-field IMRT plans, particularly for the clinically acceptable plans where average rectal doses were less for rotational plans (p = 0·009) with no statistical difference in target homogeneity. The cdrVMAT plans had significantly more MU (p = 0·005) but the average delivery time was significantly less than the IMRT plans by 42%. All clinically acceptable cdrVMAT plans were accurate in their delivery (gamma 99·2 ± 1·1%, 3%3 mm criteria). Conclusions Accurate delivery of dual partial arc cdrVMAT avoiding the couch top and rails has been demonstrated.

Dissidents with an innovation cause? Non-institutionalized actors ’ online social knowledge sharing, solution-finding tensions and technology management innovation

Purpose
– Traditionally, most studies focus on institutionalized management-driven actors to understand technology management innovation. The purpose of this paper is to argue that there is a need for research to study the nature and role of dissident non-institutionalized actors’ (i.e. outsourced web designers and rapid application software developers). The authors propose that through online social knowledge sharing, non-institutionalized actors’ solution-finding tensions enable technology management innovation.

Design/methodology/approach
– A synthesis of the literature and an analysis of the data (21 interviews) provided insights in three areas of solution-finding tensions enabling management innovation. The authors frame the analysis on the peripherally deviant work and the nature of the ways that dissident non-institutionalized actors deviate from their clients (understood as the firm) original contracted objectives.

Findings
– The findings provide insights into the productive role of solution-finding tensions in enabling opportunities for management service innovation. Furthermore, deviant practices that leverage non-institutionalized actors’ online social knowledge to fulfill customers’ requirements are not interpreted negatively, but as a positive willingness to proactively explore alternative paths.

Research limitations/implications
– The findings demonstrate the importance of dissident non-institutionalized actors in technology management innovation. However, this work is based on a single country (USA) and additional research is needed to validate and generalize the findings in other cultural and institutional settings.

Originality/value
– This paper provides new insights into the perceptions of dissident non-institutionalized actors in the practice of IT managerial decision making. The work departs from, but also extends, the previous literature, demonstrating that peripherally deviant work in solution-finding practice creates tensions, enabling management innovation between IT providers and users.

Can the scaling behavior of electric conductivity be used to probe the self-organizational changes in solution with respect to the ionic liquid structure? The case of [C8MIM][NTf2]

Electrical conductivity of the supercooled ionic liquid [C8MIM][NTf2], determined as a function of temperature and pressure, highlights strong differences in its ionic transport behavior between low and high temperature regions. To date, the crossover effect which is very well known for low molecular van der Waals liquids has been rarely described for classical ionic liquids. This finding highlights that the thermal fluctuations could be dominant mechanisms driving the dramatic slowing down of ion motions near Tg. An alternative way to analyze separately low and high temperature dc-conductivity data using a density scaling approach was then proposed. Based on which a common value of the scaling exponent [gamma] = 2.4 was obtained, indicating that the applied density scaling is insensitive to the crossover effect. By comparing the scaling exponent [gamma] reported herein along with literature data for other ionic liquids, it appears that [gamma] decreases by increasing the alkyl chain length on the 1-alkyl-3-methylimidazolium-based ionic liquids. This observation may be related to changes in the interaction between ions in solution driven by an increase in the van der Waals type interaction by increasing the alkyl chain length on the cation. This effect may be related to changes in the ionic liquid nanostructural organization with the alkyl chain length on the cation as previously reported in the literature based on molecular dynamic simulations. In other words, the calculated scaling exponent [gamma] may be then used as a key parameter to probe the interaction and/or self-organizational changes in solution with respect to the ionic liquid structure.

The four- vs. alternative six-factor structure of the French WISC-IV: Comparison using confirmatory factor analyses

Exploratory and confirmatory factor analyses reported in the French technical manual of the WISC-IV provides evidence supporting a structure with four indices: Verbal Comprehension (VCI), Perceptual Reasoning (PRI), Working Memory (WMI), and Processing Speed (PSI). Although the WISC-IV is more attuned to contemporary theory, it is still not in total accordance with the dominant theory: the Cattell-Horn-Carroll (CHC) theory of cognitive ability. This study was designed to determine whether the French WISC-IV is better described with the four-factor solution or whether an alternative model based on the CHC theory is more appropriate. The intercorrelations matrix reported in the French technical manual was submitted to confirmatory factor analysis. A comparison of competing models suggests that a model based on the CHC theory fits the data better than the current WISC-IV structure. It appears that the French WISC-IV in fact measures six factors: crystallized intelligence (Gc), fluid intelligence (Gf), short-term memory (Gsm), processing speed (Gs), quantitative knowledge (Gq), and visual processing (Gv). We recommend that clinicians interpret the subtests of the French WISC-IV in relation to this CHC model in addition to the four indices.

La réinstallation, une alternative à l'asile ?

"La réinstallation de réfugiés est, selon l’Agenda pour la protection, à la fois une solution durable, un outil de solidarité à l’égard des pays de premier asile, et un outil de protection des réfugiés. Au cours des dernières années, le concept de réinstallation a évolué de telle façon qu’il semble en voie d’acquérir un objectif supplémentaire; celui de promouvoir une migration ordonnée au détriment de l’asile dit « spontané ». L’impératif sécuritaire pousse les États de réinstallation à resserrer leur contrôle sur les flux migratoires, ce qui a d’importants impacts sur le nombre de réfugiés et de demandeurs d’asile (en baisse depuis 2003); mais ces États doivent par ailleurs respecter les obligations internationales qu’ils ont contractées précédemment à l’égard du droit des réfugiés. Dans ce contexte, une nette tendance à concevoir la réinstallation comme un contrepoids aux effets négatifs de la sécurisation des frontières, ainsi que comme une alternative à l’asile, est perceptible. Le Canada, l’un des leaders de la réinstallation au niveau mondial, participe de cette tendance."

Welfare criteria from choice: the sequential solution

We study the problem of deriving a complete welfare ordering from a choice function. Under the sequential solution, the best alternative is the alternative chosen from the universal set; the second best is the one chosen when the best alternative is removed; and so on. We show that this is the only completion of Bernheim and Rangel's (2009) welfare relation that satisfies two natural axioms: neutrality, which ensures that the names of the alternatives are welfare-irrelevant; and persistence, which stipulates that every choice function between two welfare-identical choice functions must exhibit the same welfare ordering.

Le traitement de la toxicomanie comme alternative à l’incarcération : un sentier rocailleux

Toxicomanie et criminalité sont des comportements fréquemment associés. Dans un objectif de réduction de la récidive, le traitement des toxicomanes apparaît dans la littérature américaine comme une solution plus efficace que l'incarcération et beaucoup moins dispendieuse. Qu'en est-il au Québec ? Pour répondre à cette question, 20 intervenants de la région de Montréal et de Trois-Rivières œuvrant dans le domaine de la justice, de la sécurité publique et de la santé et des services sociaux ont été rencontrés dans le cadre de groupes de discussion. Les résultats de la consultation montrent que si le traitement des toxicomanes judiciarisés est une idée intéressante en soi, plusieurs difficultés surgissent dans son application en raison notamment de la différence de culture des milieux impliqués. Cependant, une bonne communication, le respect des expertises de chacun, et une certaine tolérance vis-à-vis des objectifs de ses partenaires constituent des conditions qui rendraient possible, du moins sur papier, les expériences de déjudiciarisation en matière de toxicomanie.

Constructing a ‘moment of crisis’ and its adequate solution

The rejection of the European Constitution marks an important crystallization point for debate about the European Union (EU) and the integration process. The European Constitution was envisaged as the founding document of a renewed and enlarged European Union and thus it was rather assumed to find wide public support. Its rejection was not anticipated. The negative referenda in France and the Netherlands therefore led to a controversial debate about the more fundamental meaning and the consequences of the rejection both for the immediate state of affairs as well as for the further integration process. The rejection of the Constitution and the controversy about its correct interpretation therefore present an intriguing puzzle for political analysis. Although the treaty rejection was taken up widely in the field of European Studies, the focus of existing analyses has predominantly been on explaining why the current situation occurred. Underlying these approaches is the premise that by establishing the reasons for the rejection it is possible to derive the ‘true’ meaning of the event for the EU integration process. In my paper I rely on an alternative, discourse theoretical approach which aims to overcome the positivist perspective dominating the existing analyses. I argue that the meaning of the event ‘treaty rejection’ is not fixed or inherent to it but discursively constructed. The critical assessment of this concrete meaning-production is of high relevance as the specific meaning attributed to the treaty rejection effectively constrains the scope for supposedly ‘reasonable’ options for action, both in the concrete situation and in the further European integration process more generally. I will argue that the overall framing suggests a fundamental technocratic approach to governance from part of the Commission. Political struggle and public deliberation is no longer foreseen as the concrete solutions to the citizens’ general concerns are designed by supposedly apolitical experts. Through the communicative diffusion and the active implementation of this particular model of governance the Commission shapes the future integration process in a more substantial way than is obvious from its seemingly limited immediate problem-solving orientation of overcoming the ‘constitutional crisis’. As the European Commission is a central actor in the discourse production my analysis focuses on the specific interpretation of the situation put forward by the Commission. In order to work out the Commission’s particular take on the event I conducted a frame analysis (according to Benford/Snow) on a body of key sources produced in the context of coping with the treaty rejection.

Voronoi, Delaunay, and Block-Structured Mesh Refinement for Solution of the Shallow-Water Equations on the Sphere

Alternative meshes of the sphere and adaptive mesh refinement could be immensely beneficial for weather and climate forecasts, but it is not clear how mesh refinement should be achieved. A finite-volume model that solves the shallow-water equations on any mesh of the surface of the sphere is presented. The accuracy and cost effectiveness of four quasi-uniform meshes of the sphere are compared: a cubed sphere, reduced latitude–longitude, hexagonal–icosahedral, and triangular–icosahedral. On some standard shallow-water tests, the hexagonal–icosahedral mesh performs best and the reduced latitude–longitude mesh performs well only when the flow is aligned with the mesh. The inclusion of a refined mesh over a disc-shaped region is achieved using either gradual Delaunay, gradual Voronoi, or abrupt 2:1 block-structured refinement. These refined regions can actually degrade global accuracy, presumably because of changes in wave dispersion where the mesh is highly nonuniform. However, using gradual refinement to resolve a mountain in an otherwise coarse mesh can improve accuracy for the same cost. The model prognostic variables are height and momentum collocated at cell centers, and (to remove grid-scale oscillations of the A grid) the mass flux between cells is advanced from the old momentum using the momentum equation. Quadratic and upwind biased cubic differencing methods are used as explicit corrections to a fast implicit solution that uses linear differencing.

Metal complexes of a tetraazacyclophane: solution and molecular modelling studies

An alternative synthetic approach to yield the compound 2,3,5,6,8,9,11,14-octahydrobenzo[1][ 1,4,7,10]tetraazacyclotetradecine (bz[14]N-4) is presented. The protonation constants of bz[14]N-4 and the stability constants of its complexes with Ni2+, Cu2+, Zn2+, Cd2+, Pb2+ were determined in H2O at 25degreesC with ionic strength 0.10 mol dm(-3) in KNO3 and they were compared with structurally related macrocycles cyclam (1,4,8,11-tetraazacyclotetradecane) and cyclen (1,4,7,10-tetraazacyclododecane). These studies indicate that only 1 : 1 ( M : L) species are formed in solution, and the ligand exhibits a high affinity for larger ions such as Cd2+ and Pb2+. The X-ray study of [bz[14]N4H3](3+) shows that an inclusion compound with a chloride counter-anion is formed through NH...Cl hydrogen bonds. Spectroscopic data in solution ( electronic and NMR spectra) showed that the macrocycle adopts a planar arrangement upon metal complexation. Molecular mechanics calculations reveal that in spite of the presence of the benzene ring in the macrocyclic framework this ligand can encapsulate metal ions with different stereo-electronic sizes in square planar arrangements. Our results indicate that the presence of the benzene ring in the backbone of the bz[14]N-4 confers a coordination behaviour intermediate between that of cyclam and cyclen.

Recovery of norbixin from a raw extraction solution of annatto pigments using colloidal gas aphrons (CGAs)

Annatto dyes are widely used in food and are finding increasing interest also for their application in the pharmaceutical and cosmetics industry. Bixin is the main pigment extracted from annatto seeds and accounts for 80% of the carotenoids in the outer coat of the seeds; norbixin being the water-soluble form of the bixin. Typically annatto dyes are extracted from the seeds by mechanical means or solutions of alkali, edible oil or organic solvents, or a combination of the two depending on the desired final product. In this work CGAs are investigated as an alternative separation method for the recovery of norbixin from a raw extraction solution of annatto pigments in KOH. A volume of CGAs generated from a cationic surfactant (CTAB) solution is mixed with a volume of annatto solution and when the mixture is allowed to settle it separates into the top aphron phase and the bottom liquid phase. Potassium norbixinate presented in the annatto solution will interact with the surfactant in the aphron phase, which results in the effective separation of norbixin. Recovery= 94% was achieved at a CTAB to norbixin molar ratio of 3.3. In addition a mechanism of separation is proposed here based on the separation results with the cationic surfactant and an anionic surfactant (bis-2-ethyl hexyl sulfosuccinate, AOT) and measurements of surfactant to norbixin ratio in the aphron phase; electrostatic interactions between the surfactant and norbixin molecules result in the fort-nation of a coloured complex and effective separation of norbixin. (c) 2005 Elsevier B.V. All rights reserved.

Alternative explanations for rising dissolved organic carbon export from organic soils

Since 1988, there has been, on average, a 91% increase in dissolved organic carbon (DOC) concentrations of UK lakes and streams in the Acid Waters Monitoring Network (AWMN). Similar DOC increases have been observed in surface waters across much of Europe and North America. Much of the debate about the causes of rising DOC has, as in other studies relating to the carbon cycle, focused on factors related to climate change. Data from our peat-core experiments support an influence of climate on DOC, notably an increase in production with temperature under aerobic, and to a lesser extent anaerobic, conditions. However, we argue that climatic factors may not be the dominant drivers of DOC change. DOC solubility is suppressed by high soil water acidity and ionic strength, both of which have decreased as a result of declining sulphur deposition since the 1980s, augmented during the 1990s in the United Kingdom by a cyclical decline in sea-salt deposition. Our observational and experimental data demonstrate a clear, inverse and quantitatively important link between DOC and sulphate concentrations in soil solution. Statistical analysis of 11 AWMN lakes suggests that rising temperature, declining sulphur deposition and changing sea-salt loading can account for the majority of the observed DOC trend. This combination of evidence points to the changing chemical composition of atmospheric deposition, particularly the substantial reduction in anthropogenic sulphur emissions during the last 20 years, as a key cause of rising DOC. The implications of rising DOC export for the carbon cycle will be very different if linked primarily to decreasing acid deposition, rather than to changes in climate, suggesting that these systems may be recovering rather than destabilising.