Computational modelling in chemical engineering

Presentation given at the 60th anniversaryComputational modelling in chemical engineering: from science to technolog

Education for Sustaining Peace through Historical Memory

Informed by the author’s long-standing work on violent conflict, peace and education in countries of the Global South, particularly Colombia, this open access book presents a comprehensive narrative about the relationship between peace education, historical memory and the sustaining peace agenda, advocating for the adoption of a new perspective on education for sustaining peace through historical memory. Education on and for peace in countries wrestling with, or emerging from, protracted violent conflict is up against major challenges, and both conventional and critical approaches to peace education are limited to address these. Incorporating a focus on historical memory, without losing sight of its own pitfalls, into peace education can support learners and teachers to come to grips with achieving positive, peace-sustaining change at both the micro (individual) and macro (social and institutional) levels, and to develop concepts and practices of effective and legitimate alternatives to violence and war. Conceived in these terms, historical memory-oriented peace education also stands to enhance the work-in-progress that is the UN-led sustaining peace agenda, including its Sustainable Development Goals

Nigeria's Post-1999 Political Settlement and Violence Mitigation in the Niger Delta

Almost fifteen years after transitioning to civilian-electoral rule, Nigeria is still wrestling with the legacy of a protracted period of military government and the ‘resource curse’ associated with its huge oil wealth. The ‘Niger Delta question’, as it is often referred to in Nigeria, is not close to resolution. The region has temporarily been pacified and oil production has gone up again, though it still falls short of Nigeria’s full production potential. But the reintegration of former mid-ranking militant commanders and fighters is faltering and social unrest persists due to high youth unemployment and poverty. Large scale organised criminal activity continues, and violence could quickly re-erupt and send the Delta back to where it was before 2009 if no remedying action is taken by the Nigerian authorities and their international partners.DFI

‘External Stresses’ and Violence Mitigation in Fragile Contexts: Setting the Stage for Policy Analysis

Following on from the World Bank’s World Development Report 2011 on conflict, security and development, a debate has emerged about the role of so-called ‘external stresses’ in generating ‘new’ forms of violence and insecurity in poor and fragile countries. The Bank posits that the combination of internal stresses (e.g. low income levels, high youth unemployment) and external stresses (e.g. cross-border conflict spillovers, illicit drug trafficking) heightens the risk of different forms of violence, which are not confined to inter-state and civil war but range from communal conflicts to criminal violence and terrorism. This perspective is useful, yet a more comprehensive and nuanced framework for policy analysis is called for, based on the recognition that external stresses: (a) tend to involve external, internal as well as transnational actors and variables that are often interrelated; (b) create both losers and winners, and can promote the interests of powerful state and non-state groups in and outside of the country or world region under ‘stress’; and (c) do not all have the same kind of impact on states and societies in terms of generating violence.DFI

An improved stochastic algorithm for temperature-dependent homogeneous gas phase reactions

We propose an improved stochastic algorithm for temperature-dependent homogeneous gas phase reactions. By combining forward and reverse reaction rates, a significant gain in computational efficiency is achieved. Two modifications of modelling the temperature dependence (with and without conservation of enthalpy) are introduced and studied quantitatively. The algorithm is tested for the combustion of n-heptane, which is a reference fuel component for internal combustion engines. The convergence of the algorithm is studied by a series of numerical experiments and the computational cost of the stochastic algorithm is compared with the DAE code DASSL. If less accuracy is needed the stochastic algorithm is faster on short simulation time intervals. The new stochastic algorithm is significantly faster than the original direct simulation algorithm in all cases considered

Education for Sustaining Peace through Historical Memory

Informed by the author’s long-standing work on violent conflict, peace and education in countries of the Global South, particularly Colombia, this open access book presents a comprehensive narrative about the relationship between peace education, historical memory and the sustaining peace agenda, advocating for the adoption of a new perspective on education for sustaining peace through historical memory. Education on and for peace in countries wrestling with, or emerging from, protracted violent conflict is up against major challenges, and both conventional and critical approaches to peace education are limited to address these. Incorporating a focus on historical memory, without losing sight of its own pitfalls, into peace education can support learners and teachers to come to grips with achieving positive, peace-sustaining change at both the micro (individual) and macro (social and institutional) levels, and to develop concepts and practices of effective and legitimate alternatives to violence and war. Conceived in these terms, historical memory-oriented peace education also stands to enhance the work-in-progress that is the UN-led sustaining peace agenda, including its Sustainable Development Goals

Numerical study of a stochastic particle method for homogeneous gas phase reactions

In this paper we study a stochastic particle system that describes homogeneous gas phase reactions of a number of chemical species. First we introduce the system as a Markov jump process and discuss how relevant physical quantities are represented in terms of appropriate random variables. Then, we show how various deterministic equations, used in the literature, are derived from the stochastic system in the limit when the number of particles goes to infinity. Finally, we apply the corresponding stochastic algorithm to a toy problem, a simple formal reaction mechanism, and to a real combustion problem. This problem is given by the isothermal combustion of a homogeneous mixture of hepthane and air modelled by a detailed reaction mechanism with 107 chemical species and 808 reversible reactions. Heptane as described in this chemical mechanism serves as model-fuel for different types of internal combustion engines. In particular, we study the order of convergence with respect to the number of simulation particles, and illustrate the limitations of the method

Some Analytic Solutions for Stochastic Reactor Models Based on the Joint Composition PDF

The stochastic reactor models Partially Stirred Reactor (PaSR) and Partially Stirred Plug Flow Reactor (PaSPFR) have been investigated. These models are based on a simplified joint composition PDF transport equation. Analytic solutions for five different Cauchy problems for the PDF transport equation as given by the stochastic reactor models are presented. In all cases, molecular mixing in the stochastic reactor models is described by the LMSE mixing model. The analytic solutions have been found by combining the method of characteristics with a set of ordinary differential equations for the statistical moments to account for the functional dependence of the coefficients in the corresponding PDF transport equation. For each case an example problem is discussed to illustrate the behavior of the analytic solution