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Wolfgang Marquardt - One of the best experts on this subject based on the ideXlab platform.

  • Integrated Modeling of Work Processes and Decisions in Chemical Engineering Design
    Industrial Engineering and Ergonomics, 2009
    Co-Authors: Wolfgang Marquardt, Manfred Theißen
    Abstract:

    class relation generalization Notation Fig. 21.1: An integrated ontology for work processes and decisions Integrated Modeling of Work Processes and Decisions 271 A WorkProcess is Composed Of Work Process Elements, which form a network consisting of Work Process Nodes and Work Process Relations. Work Process Nodes comprise Action and Information elements. (An Action corresponds to an Activity in C3. The term Activity had been adopted from the terminology of the activity diagrams in UML 1.x. In the ontology, we have renamed Activity to Action in compliance with the terminology of UML 2.x.) In addition, there are Control Nodes such as Fork Nodes, which indicate the beginning of two or more control flows in parallel (the subclasses of Control Node are not given in the figure). Via the isRefinedBy relation, an Action can be linked to a subordinate WorkProcess which provides a more detailed representation of the Action on a finer level of granularity. Most Work Process Relations are binary Directed Work Process Relations characterized by a source node and a target node (relations hasSource and hasTarget). In a graphical depiction of a work process on the instance level in C3 notation, a Directed Work Process Relation is represented by an arrow from its source to its target; examples of Directed Work Process Relations include the Control Flow between Actions and/or Control Nodes and the Information Flow between Actions and Information elements. The Information Relation is a relation between two Information elements. The Synchronization of two or more Actions (not shown in the figure) is an example of a Work Process Relation which is not directed. P234: Design prod. proc. for PA6 Select mode of operation Continuous mode chosen Design reaction unit VK column ... Project P234 Design production process for PA6 Requirements for PA6 production process Process flow diagram of PA6 process P234: Select mode of operation Select mode of operation Continuous mode chosen Estimate reaction times Estimated reaction times isRefinedBy isRefinedBy Fig. 21.2: A simplistic model of a concrete Design process 272 Marquardt & Theisen To illustrate the use of the process ontology, a simplistic model of a concrete Design process for PA6 (polyamide6, a thermoplastic polymer) is shown in Fig. 21.2. On top, the overall WorkProcess “Project P234” is shown, which contains a single Action “Design production process for PA6” as well as two Information items: The “requirements” the Chemical process must fulfill are the input of the Design Action, whereas the “process flow diagram” is its output. The Design Action itself isRefinedBy a more detailed WorkProcess called “Design production process for PA6”, containing further Actions like “Select mode of operation”, which generates the output Information “Continuous mode chosen”, and “Design reaction unit”, which is based on the chosen mode of operation. For the first Action, an even more detailed WorkProcess is shown, which indicates that some characteristic reaction times had been estimated before the mode of operation was chosen. Obviously, restricting the representation of a Design process to the procedural aspect suffers from several deficiencies. The requirements for the Chemical process are hidden within a simple Information element, although they are decisive for the progress of the Design process. Also, no information is provided about the arguments that have let the Designers choose a continuous mode of operation. In particular, it is unclear why the reaction times were estimated before deciding on the mode of operation. 4 An Ontology for Design Decisions The Decision Representation Language (DRL) by LEE (1990) is an expressive, but nevertheless intuitive graphical notation for such Design rationale. Its ability for representing complex argumentations was decisive for choosing DRL as the foundation for the decision ontology described in this section. As shown in the lower part of Fig. 21.1, all classes of the ontology are derived from the abstract Decision Object. Instances of the five classes given in the left part of the figure, including the Simple Claim, form the nodes of a decision model. A DecisionProblem is a Design problem that requires a Decision; the relation IsASubdecisionOf permits to decompose a Decision. Alternatives are the options meant to solve a DecisionProblem. The desired properties of Alternatives are represented by Goals, which can be decomposed by means of IsASubGoalOf. Two further relations, Achieves and IsAGoodAlternativeFor, are used to evaluate an Alternative with respect to a Goal or a DecisionProblem, respectively. Questions are issues to be considered in the context of a DecisionProblem. Finally, a Decision represents the selection of one Alternative, i.e., it Resolves a certain DecisionProblem. Any statement in a decision model which may be subject to uncertainty or to disaccord is represented by a Claim. Claims are either SimpleClaims or relation classes derived from the abstract IsRelatedTo. In fact, most of the relations between the elements introduced above are derived from IsRelatedTo, i.e., they are Claims. For the sake of clarity, the ranges of hasSource and hasTarget for these relation classes Integrated Modeling of Work Processes and Decisions 273 are given in textual form in Fig. 21.1. For example, in case of Resolves, the range of hasSource is Decision and the range of hasTarget is DecisionProblem. The graphical representation of Resolves on the instance layer is an arrow labeled “Resolves” from a Decision instance to a DecisionProblem instance. Four additional relation classes derived from IsRelatedTo (Supports, Denies, Presupposes, and Exceeds) permit to represent complex argumentations. Denies, in particular, can be used to negate any Claim. Continuous mode PA6 production process Annual capacity of PA6: 40000 t Purity of PA6: 0.99 Molecular weight of PA6: 18000 g/mol

  • Decision process modeling in Chemical Engineering Design
    Computer Aided Chemical Engineering, 2007
    Co-Authors: Manfred Theißen, Wolfgang Marquardt
    Abstract:

    Abstract Documenting the rationale in Design processes is commonly accepted to be rewarding, but rarely done in practice due to the required time and effort. We propose an integrated approach to work process and decision modeling, characterized by both an improved usefulness of the models and less effort for their creation.

  • workflow and information centered support of Design processes the improve perspective
    Computers & Chemical Engineering, 2004
    Co-Authors: Wolfgang Marquardt, Manfred Nagl
    Abstract:

    Design process excellence is considered a major differentiating factor between competing enterprises since it determines the constraints within which plant operation and supply chain management are confined. The most important prerequisite to establish such Design process excellence is a proper management of all the Design process activities and the associated information. Starting from an analysis of the characteristics of Chemical Engineering Design processes, some important open research issues are identified. They include the development of an integrated information model of the Design process, a number of innovative functionalities to support collaborative Design, and the a-posteriori integration of existing software tools to an integrated Design support environment. Some of the results obtained and experiences gained in the last years in the collaborative research center IMPROVE at RWTH Aachen University are presented.

  • Workflow and information centered support of Design processes—the IMPROVE perspective
    Computers & Chemical Engineering, 2004
    Co-Authors: Wolfgang Marquardt, Manfred Nagl
    Abstract:

    Design process excellence is considered a major differentiating factor between competing enterprises since it determines the constraints within which plant operation and supply chain management are confined. The most important prerequisite to establish such Design process excellence is a proper management of all the Design process activities and the associated information. Starting from an analysis of the characteristics of Chemical Engineering Design processes, some important open research issues are identified. They include the development of an integrated information model of the Design process, a number of innovative functionalities to support collaborative Design, and the a-posteriori integration of existing software tools to an integrated Design support environment. Some of the results obtained and experiences gained in the last years in the collaborative research center IMPROVE at RWTH Aachen University are presented.

  • Workflow and information centered support of Design processes
    Computer Aided Chemical Engineering, 2003
    Co-Authors: Wolfgang Marquardt, Manfred Nagl
    Abstract:

    Abstract Design process excellence is considered a major differentiating factor between competing enterprises since it determines the constraints within which plant operation and supply chain management are confined. The most important prerequisite to establish such Design process excellence is a proper management of all the Design process activities and the associated information. Starting from an analysis of the characteristics of Chemical Engineering Design processes, some important open research issues are identified. They include the development of an integrated information model of the Design process, a number of innovative functionalities to support collaborative Design, and the a-posteriori integration of existing software tools to an integrated Design support environment. Some of the results obtained and experiences gained in the last years in the collaborative research center IMPROVE at RWTH Aachen University are presented.

Manfred Nagl - One of the best experts on this subject based on the ideXlab platform.

  • workflow and information centered support of Design processes the improve perspective
    Computers & Chemical Engineering, 2004
    Co-Authors: Wolfgang Marquardt, Manfred Nagl
    Abstract:

    Design process excellence is considered a major differentiating factor between competing enterprises since it determines the constraints within which plant operation and supply chain management are confined. The most important prerequisite to establish such Design process excellence is a proper management of all the Design process activities and the associated information. Starting from an analysis of the characteristics of Chemical Engineering Design processes, some important open research issues are identified. They include the development of an integrated information model of the Design process, a number of innovative functionalities to support collaborative Design, and the a-posteriori integration of existing software tools to an integrated Design support environment. Some of the results obtained and experiences gained in the last years in the collaborative research center IMPROVE at RWTH Aachen University are presented.

  • Workflow and information centered support of Design processes—the IMPROVE perspective
    Computers & Chemical Engineering, 2004
    Co-Authors: Wolfgang Marquardt, Manfred Nagl
    Abstract:

    Design process excellence is considered a major differentiating factor between competing enterprises since it determines the constraints within which plant operation and supply chain management are confined. The most important prerequisite to establish such Design process excellence is a proper management of all the Design process activities and the associated information. Starting from an analysis of the characteristics of Chemical Engineering Design processes, some important open research issues are identified. They include the development of an integrated information model of the Design process, a number of innovative functionalities to support collaborative Design, and the a-posteriori integration of existing software tools to an integrated Design support environment. Some of the results obtained and experiences gained in the last years in the collaborative research center IMPROVE at RWTH Aachen University are presented.

  • Workflow and information centered support of Design processes
    Computer Aided Chemical Engineering, 2003
    Co-Authors: Wolfgang Marquardt, Manfred Nagl
    Abstract:

    Abstract Design process excellence is considered a major differentiating factor between competing enterprises since it determines the constraints within which plant operation and supply chain management are confined. The most important prerequisite to establish such Design process excellence is a proper management of all the Design process activities and the associated information. Starting from an analysis of the characteristics of Chemical Engineering Design processes, some important open research issues are identified. They include the development of an integrated information model of the Design process, a number of innovative functionalities to support collaborative Design, and the a-posteriori integration of existing software tools to an integrated Design support environment. Some of the results obtained and experiences gained in the last years in the collaborative research center IMPROVE at RWTH Aachen University are presented.

Thomas E. Marlin - One of the best experts on this subject based on the ideXlab platform.

  • Teaching “operability” in undergraduate Chemical Engineering Design education
    Computers & Chemical Engineering, 2010
    Co-Authors: Thomas E. Marlin
    Abstract:

    Abstract This paper presents a proposal for increased emphasis on operability in the Chemical Engineering capstone Design courses. Operability becomes a natural aspect of the process Design courses for a project that is properly defined with variation in operations and model uncertainty. Key topics in operability are operating window, flexibility, reliability, safety, efficiency, operation during transitions, dynamic performance, and monitoring and diagnosis. The key barrier to improved teaching and learning of operability is identified as easily accessed and low-cost educational materials, and a proposal is offered to establish a portal open to all educators.

  • Teaching "Operability" in Undergraduate Chemical Engineering Design Education (Presented at ASEE Conference, June 2007, Honolulu)
    2008
    Co-Authors: Thomas E. Marlin
    Abstract:

    This paper presents a proposal for increased emphasis on operability in the Chemical Engineering capstone Design courses. Operability becomes a natural aspect of the process Design course for a project that is properly defined with various scenarios and uncertainty. Key topics in operability are the operating window, flexibility, reliability, safety, efficiency, operation during transitions, dynamic performance, and monitoring and diagnosis. Each is discussed in the paper with process examples and its relationship to prior learning and process Design decisions. The key barrier to improved teaching and learning of operability is identified as easily accessed and low cost educational materials, and a proposal is offered to establish a portal open to all educators.

  • AC 2007-80: TEACHING OPERABILITY IN UNDERGRADUATE Chemical Engineering Design EDUCATION
    2007
    Co-Authors: Thomas E. Marlin
    Abstract:

    This paper presents a proposal for increased emphasis on operability in the Chemical Engineering capstone Design courses. Operability becomes a natural aspect of the process Design course for a project that is properly defined with various scenarios and uncertainty. Key topics in operability are the operating window, flexibility, reliability, safety, efficiency, operation during transitions, dynamic performance, and monitoring and diagnosis. Each is discussed in the paper with process examples and its relationship to prior learning and process Design decisions. The key barrier to improved teaching and learning of operability is identified as easily accessed and low cost educational materials, and a proposal is offered to establish a portal open to all educators.

David L. Mobley - One of the best experts on this subject based on the ideXlab platform.

  • Using MD Simulations To Calculate How Solvents Modulate Solubility
    Journal of chemical theory and computation, 2016
    Co-Authors: Shuai Liu, Shannon Cao, Kevin Hoang, Kayla L. Young, Andrew S. Paluch, David L. Mobley
    Abstract:

    Here, our interest is in predicting solubility in general, and we focus particularly on predicting how the solubility of particular solutes is modulated by the solvent environment. Solubility in general is extremely important, both for theoretical reasons - it provides an important probe of the balance between solute-solute and solute-solvent interactions - and for more practical reasons, such as how to control the solubility of a given solute via modulation of its environment, as in process chemistry and separations. Here, we study how the change of solvent affects the solubility of a given compound. That is, we calculate relative solubilities. We use MD simulations to calculate relative solubility and compare our calculated values with experiment as well as with results from several other methods, SMD and UNIFAC, the latter of which is commonly used in Chemical Engineering Design. We find that straightforward solubility calculations based on molecular simulations using a general small-molecule force field outperform SMD and UNIFAC both in terms of accuracy and coverage of the relevant Chemical space.

Horst Kehlen - One of the best experts on this subject based on the ideXlab platform.

  • Thermodynamics of semicontinuous mixtures using equations of state with group contributions
    Fluid Phase Equilibria, 1997
    Co-Authors: Uwe Baer, D. Browarzik, Horst Kehlen
    Abstract:

    Abstract In the Chemical Engineering Design of industrial distillation columns data on the vapor-liquid equilibrium of complex mixtures are very important. Because of the expense of the experimental determination of such data, there is interest in their accurate prediction. Multicomponent mixtures such as petroleum or petroleum fractions contain a large number of similar Chemical species. The method of continous thermodynamics is suitable for the description of the vapor-liquid equilibria of these systems. Continuous thermodynamics is based on the application of a continuous distribution function for describing the composition of multicomponent mixtures. Coupled with activity coefficient models, this method is shown to be convenient for the prediction of vapor-liquid equilibria. However, applications have been limited to low pressures. Therefore, in this paper a model for the prediction of vapor-liquid equilibria based on a two-parameter cubic equation of state is developed. These parameters are calculated using the mixing rule of Wong and Sandler [1] which allows the inclusion of group contribution models (e.g. UNIFAC, modified UNIFAC or ASOG).