A model-driven software engineering workflow and tool architecture for servitised manufacturing

Modern manufacturing businesses increasingly engage in servitisation, by offering advanced services along with physical products, and creating “product–service systems”. Information Technology infrastructures, and especially software, are a critical part of modern service provision. However, software development in this context has not been investigated and there are no development methods or tools specifically adapted to the task of creating software for servitised businesses in general, or manufacturing in particular. In this paper, we define the requirements for software engineering in servitised manufacturing. Based on these, we describe a model-driven software engineering workflow for servitised manufacturing, supporting both structural and behavioural modelling of the service system. Furthermore, we elaborate on the architecture of an appropriate model-driven Integrated Development Environment (IDE). The proposed workflow and a prototype implementation of the IDE were evaluated in a set of industrial pilots, demonstrating improved communication and collaboration between participants in the software engineering process.     

Simplified hydrolysis models for the optimal design of two-stage anaerobic digestion.

This note shows that Contois kinetics, when used to describe the hydrolysis of biodegradable solids, are preferable to the traditional first-order kinetics when considering the optimal design of a steady-state two-stage anaerobic digester system.     

Combined chemical and biological treatment of azo dye-containing wastewaters

Wastewaters produced in textile industrial processes contain organic dyes, such as azo dyes, which are not amenable to direct biological treatment. This work examines the possibility of combining ozonation with biological treatment for the effective treatment of wastewaters containing the azo dye Orange II. Oxalate, formate, and benzene-sulfonate are found to be the final products of ozonation. Sulfonated aromatics such as benzene-sulfonate cause organic pollution and are not readily degradable because of their xenobiotic character. For the biological treatment of the ozonation products, activated sludge acclimated to the main product (benzene-sulfonate) was used, and batch experiments under aerobic conditions were performed. On the basis of experimental data, mathematical models describing both processes were developed. An overall mathematical model describing the integrated chemical and biological treatment of the dye was used to estimate the cost of the whole process. The implications of this study for the design of effective dye-containing wastewater treatment plants are discussed.     

Sensitivity analysis of a biofilm model describing mixed growth of nitrite oxidisers in a CSTR.

A simple kinetic model has been developed for describing nitrite oxidation by autotrophic aerobic nitrifiers in a CSTR reactor, in which mixed (suspended and attached) growth conditions are prevailing. In this work, a critical dimensionless parameter is identified containing both biofilm characteristics and microbial kinetic parameters, as well as the specific (per volume) surface of the reactor configuration used. Evaluation of this dimensionless parameter can easily provide information on whether or not wall attachment is critical, and should be taken into account either in kinetic studies or in reactor design, when specific pollutants are to be removed from the waste influent stream. The effect of bulk dissolved oxygen (DO) concentration on the validity of this model is addressed and minimum non-limiting DO concentrations are proposed depending on the reactor configuration.     

Application of ADM1 for the simulation of anaerobic digestion of olive pulp under mesophilic and thermophilic conditions.

The management of the wastewater originating from olive oil producing industries poses a serious environmental problem. Recently, two-phase production of olive oil has been developed, leading to almost complete elimination of the bulk of the generated wastewater and, is thus regarded as an environmentally friendly technology. However, the main waste stream (olive pulp) is a slurry material characterized by high solids concentration (approximately 30%), requiring stabilisation before its final disposal. The anaerobic digestion of olive pulp is studied in this work under mesophilic and thermophilic conditions in CSTR-type digesters. The digesters were fed with water-diluted (1:4) olive pulp at an HRT of 20 days and an OLR of 3.94 kg COD m(-3) d(-1). In order to study the process kinetics, the digesters were subjected to impulse disturbances of different substrates. The IWA anaerobic digestion model was used to simulate the reactors' response. Some key process parameters, such as the specific maximum uptake rate constants and the saturation constants for the volatile fatty acids degradation were estimated and compared with the standard values suggested by the ADM1.