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This market research paper has been prepared under the supervision of Prof. Dr. Wolfgang Veit of Cologne University of Applied Sciences and Prof. Dr. Carol Scovotti of University of Wisconsin-Whitewater in the course of the inter-university cross-border collaboration student research project “Export Opportunity Surveys (EOS)”. This study explores organic oats export opportunities to the German and US markets.
Online-measurement systems for agricultural and industrial AD plants – A review and practice test
(2014)
Online-measurement systems for AD plants in general are crucial to allow for detailed and comprehensive process monitoring and provide a basis for the development and practical application of process optimisation and control strategies.
Nevertheless, the online measurement of key process variables such as Volatile Fatty Acids (VFA) and Total Alkalinity (TA) has proven to be difficult due to extreme process conditions. High Total Solids (TS) concentrations and extraneous material often damage the sensors or have a strong negative impact on measurement quality and long-term behaviour.
Consequently, there is a need for new robust and accurate online-measurement systems.
The purpose of this paper is to give an overview of existing online-measurement systems, to present the current state of research and to show the results of practice tests at an agricultural and industrial AD plant. It becomes obvious that a broad variety of measurement solutions have been developed over the past few years, but that the main problem is the upscaling from lab-scale to practical application at full-scale AD plants. Results from the practice tests show that an online-measurement of pH, ORP, TS is possible.
In this paper a closed-loop substrate feed control for agricultural biogas plants is proposed. In this case, multi-objective nonlinear model predictive control is used to control composition and amount of substrate feed to optimise the economic feasibility of a biogas plant whilst assuring process stability. The control algorithm relies on a detailed biogas plant simulation model using the Anaerobic
Digestion Model No. 1. The optimal control problem is solved using the state-of-the-art multi-objective optimization method SMS-EGO. Control performance is evaluated by means of a set point tracking problem in a noisy environment.
Results show, that the proposed control scheme is able to keep the produced electrical energy close to a set point with an RMSE of 0.9 %, thus maintaining optimal biogas plant operation.
Anaerobic Digestion of spent grains: Potential use in small-scale Biogas Digesters in Jos, Nigeria
(2014)
In order to ascertain biogas yield potential and applicability of spent grains (SG)1 in small-scale biogas production, laboratory batch fermentation was performed with various masses of dry and wet SG using sewage sludge (SS)2 and digested maize silage (DMs) 3 as inoculums. Different volumes of biogas and CH4 were measured with higher volumes observed for batch fermentation with DMs in com-parison to those produced by SS. Results from the study reveals minimum biogas yield of 118.10 L/kg
VS and maximum yields of 769.46 L/kg VS, which are indicative of the possible use of SG for domestic biogas production in Jos, Nigeria. The study established the fact that the use of both dry and wet SG results in the yield of a useful amount of biogas having 40 - 60 % CH4 content depending on the inoculum and amount of volatile solids present. Using the parameters of dry matter and volatile solids contents analysed for SG and DMs, it was estimated that a reactor volume of 6.47 m3 would be capable of meeting the daily cooking needs of rural households in Jos, Nigeria.
The utilization of roadside-green-cuttings (grass) for anaerobic digestion increases provides an additional possible source of organic waste for use as a renewable energy source. Grass can be used as a substrate to increase biogas yield. Nevertheless, the anaerobic digestion of this kind of waste can be limited due to the fact that it could be contaminated with heavy metals, in particular from traffic emissions and industrial activity. For this reason the biogas production of grass from a busy road was assessed. Samples of roadside-grass were washed with an organosulphide, which is used for the removal of heavy metals from wastewater.
A comparison of the anaerobic digestion of washed and unwashed roadside grass was performed. Results showed that the anaerobic digestion of the unwashed grass was much more effective than the washed grass. A second experiment was carried out and co-fermentation of manure and farm-grass was prepared for anaerobic digestion. Lead was added in the concentrations 500, 1000 and 2000 mg Pb2+/kg. The results showed that the higher the lead concentration, the lower the inhibition of the biogas yield. The grass could be acting as phytoremediator for high lead concentrations. The grass could contain organic compounds, which can as-similate heavy metals.
The amount of data produced and stored in multiple types of distributed data sources is growing steadily. A crucial factor that determines whether data can be analyzed efficiently is the use of adequate visualizations. Almost simultaneously with the ongoing availability of data numerous types of visualization techniques have emerged. Since ordinary business intelligence users typically lack expert visualization knowledge, the selection and creation of visualizations can be a very time- and knowledge-consuming task. To encounter these problems an architecture that aims at supporting ordinary BI users in the selection of adequate visualizations is developed in this thesis. The basic idea is to automatically provide visualization recommendations based on the concrete BI scenario and formalized visualization knowledge. Ontologies that formalize all relevant knowledge play an important role in the developed architecture and are the key to make the knowledge machine-processable.
This paper is grounded in the emerging field of web science and shall contribute to its further classification and demarcation by illustrating the current state of »web-native research methods«. It builds upon an initial arraying work of Richard Rogers, who coined the term »Digital Methods« for research with methods that were »born« in the web, and illustrated and organized them in his eponymous book in 2013. This paper attempts to develop a more appropriate illustration of the Digital Methods by following the web’s very own, hypertextual, network-like nature, in particular by construing an ontological representation on the base of the Web Ontology Language (OWL). By virtue of decomposing the book into granular information units and their subsequent reassembly into OWL entities, immediate access to the entire knowledge domain can be provided, and coherencies, interrelations and distinctions between concepts become apparent. The ontology’s structure was induced narrowly along the provided examples of research projects and subsequently clustered in topic groups, of which the three most important ones were (a) the Digital Methods as an arraying space of web-native methodology, (b) a collection of concrete applications of these Digital Methods in research projects, and (c) a hierarchical scheme of traditional sciences with a distinct interest in answering research questions with help of Digital Methods. Subsequently, the ontology was evaluated in three general dimensions: Deriving user stories and scenarios provided means to validate the utilization quality; the accuracy and reliability of the resulting structure was validated with help of a control group of web-native research projects; and process control instruments served as a validator for the ontology’s correctness. Despite the ontology itself, this paper also resulted in a first interpretation of the produced information: Statements about research practise in social science, politics and philosophy were as possible as findings about commonly applied varieties of methods. Concluding, the present paper proposes a process of ontology engineering, an evaluation of the ontology’s value, and an interpretation of the ontology’s content.
This paper gives an overview of the development of Fair Trade in six European countries: Austria, France, Germany, the Netherlands, Switzerland and the United Kingdom. After the description of the food retail industry and its market structures in these countries, the main European Fair Trade organizations are analyzed regarding their role within the Fair Trade system. The following part deals with the development of Fair Trade sales in general and with respect to the products coffee, tea, bananas, fruit juice and sugar. An overview of the main activities of national Fair Trade organizations, e.g. public relation activities, completes the analysis. This study shows the enormous upswing of Fair Trade during the last decade and the reasons for this development. Nevertheless, it comes to the conclusion that Fair Trade is still far away from being an essential part of the food retail industry in Europe.
This paper presents a series of flow and temperature measurements on the principal heat network of :metabolon in Lindlar, Germany. These measurements intend to show the behaviour of the system on specific production areas of :metabolon for future monitoring and optimisation purposes. Such measurements allow the analysis of the system’s heat flow through the network, which showed that losses exist, some areas. The results demonstrate successfully that the temperature and flow changes deserve more detailed and fixed monitoring in specific areas to help the user decide the optimum measuring point.