An assessment of the viability of alternatives to biodiesel transport fuels

© 2019 Elsevier Ltd This work presents an economic feasibility study of using algae and biochar burial strategies to offset carbon emission from the use of conventional fossil-derived transport fuels. The economic feasibility is quantified on the basis that the final price of the decarbonised fossil-derived diesel should be lower or equal to the price of biodiesel which is deemed to be the next best alternative. The extra costs associated with the carbon capture/offset via algae and biochar burial are estimated for the most typical scenarios using the economic models developed as part of this work. In addition, High Dimensional Model Representation based global sensitivity analyses are performed in order to quantify the influence of key model parameters on the overall costs. It was found that using algae burial to offset carbon emissions is not viable for principle reasons such as the amount of water required and the burial of phosphate as well as more than doubling the current diesel price. This price is mainly due to the high costs of pumping dilute algae slurry underground. The biochar burial approach, on the other hand, was found to be much more economically viable as it only increases the conventional diesel price by a small amount. This comparably low price is due to the revenue generated from selling the electricity produced from the pyrolysis by-products. In addition, the global sensitivity analysis revealed that the overall costs were the most sensitive to the wood price, as the wood feedstock may either be an income or an expenditure

Imprinting founders’ blueprints on management control systems

In this paper we seek to understand the influence of founders on the design and use of management control systems (MCS) through a theoretical lens known as imprinting. The organizational literature shows that founders are a source of imprinting, since their unique background informs the blueprint for their organization, which can affect patterns of organizational design and development. We undertake a case study of an innovative early-stage growth-focused manufacturing firm established by founders who espoused a commitment blueprint (one of five possible blueprints). Founders who have a commitment blueprint aim to establish a workplace where employees feel an intense emotional attachment to each other and the firm and are passionate about the firm's vision. We examine how founders’ commitment blueprint influences the design and use of MCS. We show that the imprint of a founder's commitment blueprint is reflected in the design and use of cultural controls and employee selection to establish a workplace that fosters an intense emotional attachment and identification comparable to a family's, with an organizational culture where employees are committed and passionate about the firm. While these controls have previously been shown to make up the central components of a commitment blueprint, our results reveal a reliance on cultural controls and employee selection is not exclusive, but supported and reinforced through managers’ design and use of personnel controls, results controls, action controls, penalties, and informal controls. We also find a reluctance to implement controls that are seen as bureaucratic, since it is felt they would negatively influence the organizational culture

Modelling PAH curvature in laminar premixed flames using a detailed population balance model

© 2016 The Combustion Institute A detailed population balance model, which includes the kinetic Monte Carlo-aromatic site (KMC-ARS) model for detailed polycyclic aromatic hydrocarbon (PAH) growth, is used to compute the Gauss curvature of PAHs in laminar premixed ethylene and benzene flames. Previous studies have found that capping of an embedded 5-member ring causes curvature in graphene edges. In this work, a capping process is added to the KMC-ARS model with the rate coefficient of the capping reaction taken from the work of You et al. (2011). We demonstrate that the Gauss–Bonnet theorem can be used to derive a correlation between the number of 5- and 6-member rings in a PAH and its Gauss curvature (or radius of curvature), independent of where the 5-member ring is embedded within the PAH structure. Numerical simulation yields satisfactory results when compared to the experimentally determined Gauss curvature reported in the literature. Computed and experimental fringe length distributions are also compared and the results suggest that PAHs smaller than the size required for inception are able to condense onto particles.This research is supported by the National Research Foundation, Prime Minister’s Office, Singapore under its CREATE programme. Mr. Edward K. Y. Yapp was supported by the Gates Cambridge, Cambridge, UK. Prof. Markus Kraft was supported by the Weierstrass Institute for Applied Analysis and Stochastics, Berlin, Germany

A detailed particle model for polydisperse aggregate particles

The mathematical description of a new detailed particle model for polydisperse aggregate particles is presented. An aggregate particle is represented as a collection of overlapping spherical primary particles and the model resolves the composition, radius and position coordinates of each individual primary to form a detailed geometrical description of aggregate morphology. Particles transform under inception, coagulation, surface growth, sintering and coalescence processes. The new particle description is used to model the aerosol synthesis of titanium dioxide (TiO2) aggregates from titanium tetraisopropoxide (TTIP) precursor. TiO2 particles are formed through collision-limited inception and growth reactions of Ti(OH)4 from the gas-phase, produced from the thermal decomposition of TTIP. Coupling between the particle population balance and detailed gas-phase chemistry is achieved by operator splitting. A numerical study is performed by simulating a simple batch reactor test case to investigate the convergence behaviour of key functionals with respect to the maximum number of computational particles and splitting time step. Finally, a lab-scale hot wall reactor is simulated to demonstrate the advantages of a detailed geometrical description. Simulated particle size distributions were in reasonable agreement with experimental data. Further evaluation of the model and a parametric sensitivity study are recommended

The emergence of management controls in an entrepreneurial company

The dilemma faced by founders of entrepreneurial companies is how to scale their business while staying in control. While the accounting literature has found that financial controls are important to rapidly scale a business, we do not know how these controls emerge in entrepreneurial companies in relation to other management controls. Using a case study of an entrepreneurial company that rapidly scaled its business, this study examines the management controls that emerged to become a package of controls. We highlight the importance of the management control package remaining in balance, with controls working together interdependently in a complementary fashion

Workplace experience of radiographers: impact of structural and interpersonal interventions

PURPOSE: Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. METHODS: A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. RESULTS: At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. CONCLUSION: Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period

Design technologies for eco-industrial parks: From unit operations to processes, plants and industrial networks

© 2016 Elsevier Ltd. The concept of eco-industrial park (EIP) has recently become the subject of a great deal of attention from industry and academic research groups. This paper proposes a series of systematic approaches for multi-level modelling and optimisation in EIPs. The novelties of this work include, (1) building a four-level modelling framework (from unit level to process level, plant level and industrial network level) for EIP research, (2) applying advanced mathematical modelling methods to describe each level operation, (3) developing efficient methodologies for solving optimisation problems at different EIP levels, (4) considering symbiotic relations amongst the three networks (material, water and energy networks) at the top EIP level with the boundary conditions of economic, social and legal requirements. For methodology demonstration, two cases at process level and industrial network level respectively are tested and solved with the developed modelling and optimisation strategies. Finally, the challenges and applications in future EIP research are also discussed, including data collection, the extension of the current networks to EIPs, and the feasibility of the proposed methodologies for complex EIP problems. The extended EIPs include the combination of material exchanges, energy systems and waste-water treatment networks. The aspects considered for future industrial ecology are carbon emission, by-product reuse, water consumption, and energy consumption. The main object of this paper is to explain the detailed model construction process and the development of optimisation approaches for a complex EIP system. In future work, this system is expected to share services, utility, and product resources amongst industrial plants to add value, reduce costs, improve environment, and consequently achieve sustainable development in a symbiosis community

Modelling of soot formation in a diesel engine with the moment projection method

© 2017 The Author(s). In this work, the recently developed moment projection method (MPM) is coupled with the Stochastic Reactor Model engine code to simulate the formation of soot in a direct injection diesel engine. The simulations take into account convective heat transfer, turbulent mixing, and adopts a detailed chemical mechanism so that the concentrations of soot precursors can be predicted. The soot model considered in this work is based on integration and modification of existing sub-models for soot inception, coagulation, condensation, surface growth and oxidation. The soot moment equations are solved using MPM which has been proven to be accurate and robust. A single-cylinder research version of the Great Wall 4D20 diesel engine with exhaust gas recirculation is modelled for two test cases with different injection timings, injection pressures and fuel consumptions. Simulations are fast (on the order of minutes) and comparison of computed and experimental pressure and heat release rate are in excellent agreement. The amount of soot produced is in qualitative agreement with measurements of diesel smoke opacity.This research is supported by the National Research Foundation, Prime Minister’s office, Singapore under its CREATE programme

Extension of moment projection method to the fragmentation process

© 2017 Elsevier Inc. The method of moments is a simple but efficient method of solving the population balance equation which describes particle dynamics. Recently, the moment projection method (MPM) was proposed and validated for particle inception, coagulation, growth and, more importantly, shrinkage; here the method is extended to include the fragmentation process. The performance of MPM is tested for 13 different test cases for different fragmentation kernels, fragment distribution functions and initial conditions. Comparisons are made with the quadrature method of moments (QMOM), hybrid method of moments (HMOM) and a high-precision stochastic solution calculated using the established direct simulation algorithm (DSA) and advantages of MPM are drawn