Direct discretizations of bi-variate population balance systems with finite difference schemes of different order

The accurate and efficient simulation of bi-variate population balance systems is nowadays a great challenge since the domain spanned by the external and internal coordinates is five-dimensional. This report considers direct discretizations of this equation in tensor-product domains. In this situation, finite difference methods can be applied. The studied model includes the transport of dissolved potassium dihydrogen phosphate (KDP) and of energy (temperature) in a laminar flow field as well as the nucleation and growth of KDP particles. Two discretizations of the coupled model will be considered which differ only in the discretization of the population balance equation: a first order monotone upwind scheme and a third order essentially non-oscillatory (ENO) scheme. The Dirac term on the right-hand side of this equation is discretized with a finite volume method. The numerical results show that much different results are obtained even in the class of direct discretizations

Finite element LES and VMS methods on tetrahedral meshes

AbstractFinite element methods for problems given in complex domains are often based on tetrahedral meshes. This paper demonstrates that the so-called rational Large Eddy Simulation model and a projection-based Variational Multiscale method can be extended in a straightforward way to tetrahedral meshes. Numerical studies are performed with an inf–sup stable second order pair of finite elements with discontinuous pressure approximation

A numerical method for the simulation of an aggregation-driven population balance system

A population balance system which models the synthesis of urea is studied in this paper. The equations for the flow field, the mass and the energy balances are given in a three-dimensional domain and the equation for the particle size distribution (PSD) in a four-dimensional domain. This problem is convection-dominated and aggregation-driven. Both features require the application of appropriate numerical methods. This paper presents a numerical approach for simulating the population balance system which is based on finite element schemes, a finite difference method and a modern method to evaluate convolution integrals that appear in the aggregation term. Two experiments are considered and the numerical results are compared with experimental data. Unknown parameters in the aggregation kernel have to be calibrated. For appropriately chosen parameters, good agreements are achieved of the experimental data and the numerical results computed with the proposed method. A detailed study of the computational results reveals the influence of different parts of the aggregation kernel

A numerical method for the simulation of an aggregation-driven population balance system

A population balance system which models the synthesis of urea is studied in this paper. The equations for the flow field, the mass and the energy balances are given in a three-dimensional domain and the equation for the particle size distribution (PSD) in a four-dimensional domain. This problem is convection-dominated and aggregation-driven. Both features require the application of appropriate numerical methods. This paper presents a numerical approach for simulating the population balance system which is based on finite element schemes, a finite difference method and a modern method to evaluate convolution integrals that appear in the aggregation term. Two experiments are considered and the numerical results are compared with experimental data. Unknown parameters in the aggregation kernel have to be calibrated. For appropriately chosen parameters, good agreements are achieved of the experimental data and the numerical results computed with the proposed method. A detailed study of the computational results reveals the influence of different parts of the aggregation kernel

Askwith Library Services - Guerilla Test of Advance Media Booking Service

The purpose of this test was to assess the overall usability of the Advance Media Booking interface, to identify any common problems users encountered with the interface, and recommend possible changes to improve the interface.Usability Grouphttp://deepblue.lib.umich.edu/bitstream/2027.42/107008/1/AskwithGuerillaTest.pd

Guerilla Test of Library Gateway Navigation Menu

The goal of this test was to determine if users understood the functionality and menu items of the global navigation menu on the Gateway. Specifically, we wanted to learn if users understood that the menu provided access to global library information as opposed to local (specific) library information. In addition, we also asked users about their preferences on how specific library web pages should be listed when they click on the MLibraries menu option.Usability Grouphttp://deepblue.lib.umich.edu/bitstream/2027.42/107010/1/Gateway_Header_Guerilla_Report.pd

A numerical method for the simulation of an aggregation-driven population balance system

SUMMARY A population balance system that models the synthesis of urea is studied in this paper. The equations for the flow field, the mass and the energy balances are given in a three-dimensional domain, while the equation for the particle size distribution is given in a four-dimensional domain. This problem is convection-dominated and aggregation-driven. Both features require the application of appropriate numerical methods. This paper presents a numerical approach for simulating the population balance system, which is based on finite element schemes, a finite difference method and a modern method to evaluate convolution integrals that appear in the aggregation term. Two experiments are considered and the numerical results are compared with experimental data. Unknown parameters in the aggregation kernel have to be calibrated. For appropriately chosen parameters, good agreements are achieved of the experimental data and the numerical results computed with the proposed method. A detailed study of the computational results reveals the influence of different parts of the aggregation kernel

A numerical method for the simulation of an aggregation-driven population balance system

SUMMARY A population balance system that models the synthesis of urea is studied in this paper. The equations for the flow field, the mass and the energy balances are given in a three-dimensional domain, while the equation for the particle size distribution is given in a four-dimensional domain. This problem is convection-dominated and aggregation-driven. Both features require the application of appropriate numerical methods. This paper presents a numerical approach for simulating the population balance system, which is based on finite element schemes, a finite difference method and a modern method to evaluate convolution integrals that appear in the aggregation term. Two experiments are considered and the numerical results are compared with experimental data. Unknown parameters in the aggregation kernel have to be calibrated. For appropriately chosen parameters, good agreements are achieved of the experimental data and the numerical results computed with the proposed method. A detailed study of the computational results reveals the influence of different parts of the aggregation kernel

A Cloud-Based Collaboration Platform for Model-Based Design of Cyber-Physical Systems

Businesses, particularly small and medium-sized enterprises, aiming to start up in Model-Based Design (MBD) face difficult choices from a wide range of methods, notations and tools before making the significant investments in planning, procurement and training necessary to deploy new approaches successfully. In the development of Cyber-Physical Systems (CPSs) this is exacerbated by the diversity of formalisms covering computation, physical and human processes. In this paper, we propose the use of a cloud-enabled and open collaboration platform that allows businesses to offer models, tools and other assets, and permits others to access these on a pay-per-use basis as a means of lowering barriers to the adoption of MBD technology, and to promote experimentation in a sandbox environment

Current Perspectives on Awareness Information to Support Real-Time Communication

Abstract-Sharing awareness information to help remote people establish real-time communication has been a research area for the past couple decades. Much of the work so far has focused on sharing awareness for communication availability in the work setting. Yet several recent trends suggest the need to reconsider the contexts and assumptions around awareness research. Increasing deployment of communication technology in homes and the blurring of home and work boundaries means that more communication interactions involve the home. The popularity of mobile smartphones adds the mobile context and the sensor capabilities integrated into mobile devices. Given the broadened scope of where and how communication occurs and the importance of being able to smoothly negotiate starting and ending conversations, there is an opportunity to reconsider awareness research in today's environment. We identify current challenges and opportunities in awareness research from perspectives beyond focusing just on the workplace to include technologies and use practices in the home and mobile contexts. Keywords-awareness; availability; presence; awareness; computer-mediated communication; workplace; home; mobile I. RECONSIDERING AWARENESS INFORMATION For the past couple decades, research on presence and awareness has explored how to help people time and negotiate their attempts to establish communication over distance. Yet during the course of those years, much of the technology and use practice landscape has changed in ways that have a direct impact on how people use and interpret awareness information. The increased use of computer-mediated communication (CMC) in the home adds a distinctly different context in which to establish communication. The growing popularity of mobile smartphones not only adds a mobile context for establishing communication, but also offers new sensing capabilities that increases the amount of awareness information available. In light of these recent developments, we identify several important dimensions for reconsidering awareness information to support real-time communication. A. Awareness in the Workplace Context Much of the prior awareness research has focused on workbased communication, typically in the office setting of a work environment. For example, the early Media Space work Hudson et al. [4] conducted an Experience Sampling Method study to identify what are the strongest indicators for availability in the workplace. They concluded that the presence of speech (i.e., that a person was already engaged in conversation with someone else) was strongly correlated with being unavailable for new interaction. Sophisticated models for predicting presence and availability based on on-line calendar and computer activity information that is readily available have also been developed in the work context [5], [6]. More recently, Dugan et al. Sharing awareness in the workplace can leverage many resources and conditions that are typical of a work environment. The traditionally higher performance computin