Use Of A Web Based Virtual Laboratory To Introduce Mass Transfer Processes In Environmental Engineering And Science Courses

This paper describes the development of a web-based laboratory as a means to introduce advanced mass transfer processes concepts in environmental engineering and science courses. This web-based laboratory is comprised of interactive user-friendly input interfaces, customizable output interfaces, illustrative Help and Tutorial sections, a relational database, and a finite element in space and finite difference in time numerical engine. Architecture used to develop and implement this system is briefly discussed. The virtual laboratory employs spherical particles representative of a number of matrices of interest to environmental engineers, including water treatment systems and subsurface contaminant fate and transport. Users of the laboratory may define physical and chemical characteristics of up to five different particles, including up to five separate reactive regions within each particle. Complex mass transfer processes, including linear and nonlinear sorption and Fickian and non-Fickian diffusion processes, are capable of being modeled for each reactive domain within each particle. Two types of boundary conditions, reflective of completely mixed flow reactors and completely mixed batch reactors, are also included. Illustrations of the education benefits derived from use of the web-based laboratory are demonstrated by two examples. Introduction Understanding the complex processes controlling the mass distribution, transportation, reaction, and transformation of contaminants within the natural or engineered environment is critical for sustainable agricultural practices, water and wastewater treatment, and effective and efficient contaminant remediation. Communicating an understanding of the underlying concepts of mass transfer processes, however, has been a difficult challenge in civil and environmental engineering education [1]. While students may be well-grounded in the fundamental theories of mass transfer processes after completion of traditional coursework, they may not be as well prepared to transition to practicing engineering and conducting state-of-the-art research, because of the inability to apply known concepts to new problems, and the inability or reluctance to construct numerical models. Proceedings of the 2003 American Society for Engineering Education Annual Conference & Exposition Copyright © 2003, American Society for Engineering P ge 8.227.1 This paper describes the development of a virtual mass transfer processes laboratory (MTPL) as a means to introduce advanced mass transfer concepts in environmental engineering and science courses. Subsequent to this introduction, descriptions of the conceptual and numerical models of MTPL are presented. Following a brief presentation of the system architecture, system components are introduced. Illustrations of the educational benefits that may be derived from use of the web-based laboratory are then demonstrated by the presentation of two case studies. Mass Transfer Processes Laboratory Conceptual Model MTPL models mass transfer into and out of spherical particles in two types of ideal reactors: completely mixed flow reactors (CMFR) and completely mixed batch reactors (CMBR). Twelve different types of mass transfer conditions, corresponding to linear and nonlinear sorption with Fickian and/or non-Fickian diffusion processes, are coupled with different boundary conditions of the CMFR and CMBR. These problems are solved numerically by using finite element method in space and finite difference method in time. Up to five different types of particles, with up to five separate reactive domains in each particle, can be used in MTPL. Mass Transfer Processes Laboratory System Architecture This web-based laboratory is comprised of interactive user-friendly input interfaces, customizable output interfaces, illustrative Help and Tutorial sections, which are supported by a relational database, and a finite element in space and finite difference in time numerical engine. CORBA technology provides the connection between the numerical model and the web server. Figure 1 provides a general illustration of the MTPL system architecture.