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Dr. Shri Ramaswamy

Professor and Department Head
Ph.D. 1990, State University of New York
Bio-based Products Engineering, Paper science and engineering
Phone: (612) 624-8797
E-mail: shri@umn.edu
Ramaswamy Research Group website

Areas of Interest
Transport in porous media, process engineering and product development, bio-based polymers

We come across porous materials in many walks of life including rocks, sand, biological materials and wood, paper and board. Our research primarily centers around developing a better understanding of the fundamental characteristics of porous materials and how they relate to transport processes. This is then used in designing more energy efficient manufacturing processes and also “engineer” products specifically tailored to meet required end-use applications.

View 3D image of cellulose fiber structure (paper) using high resolution (~1.0 micron) X-ray micro computed tomography (obtained in collaboration with PFI, Norway) (30MB .avi file)

Using X-ray micro computed tomography (X- µCT), a relatively new technique used in advanced materials research, we are developing sophisticated methods to visualize and characterize the complex, internal and surface three-dimensional structure of porous materials. These provide a non-intrusive tool to quantify the structural details such as porosity, interfacial area, tortuosity, pore size distribution, structural anisotrophy etc.

Using the Minnesota Supercomputing Institute resources, we are also developing numerical methods such as Brownian motion random walk simulation to estimate the transport properties of porous media such as diffusivity, permeability, conductivity using actual 3D images. Working in collaboration with a consortium of international researchers we are in the process of developing high resolution tomography techniques (using facilities in the European Synchrotron Radiation Facility (ESRF, Grenoble, France)) as well as additional methods for estimating transport, mechanical and optical properties of porous media.

One of our other major research effort focuses on theoretical and experimental methods to study fluid flow and heat and mass transfer in compressible porous media. In many consumer product applications such as tissue and towel products optimizing energy efficiency and end-use product properties are intricately related to the internal structure and transport. Our current effort focuses on through air drying of tissue and towel, role of non-uniformity on momentum, heat and mass transfer in porous media, vacuum dewatering and in-plane and transverse permeability of porous media.

View video of exit air temperature distribution during convective drying of tissue (2.5MB .avi file)

A relatively new area of study is transport and degradation kinetics of bio-based polymers. Emerging bio-products (derived from renewable bio-resources) such as Poly Lactic Acid can be used in making many of the day-to-day products such as plates, cups, etc. One of the interesting aspects of these products is that they are bio-degradable. Our research, funded by the Initiative on Renewable Energy and the Environment (IREE), aims to better understand the transport of moisture in bio-based polymers and how they relate to changes in crystallinity and mechanical properties. This will then be used in optimizing the composition and manufacturing process of PLA.

Courses Taught

* BP 4401/5401 Bio-based Products Engineering
* BP 4502W Process and Products Design II
* BP 4313/5313 Pulp and Paper Unit Operations
* BP 4314/5314 Papermaking Processes and Process Engineering Laboratory

Selected Publications

Ramaswamy, S., M. Gupta, A. Goel, U. Aaltosalmi, M. Kataja, A. Koponen, B.V. Ramarao, “The 3D structure of fabric and its relationship to liquid and vapor transport” , Colloids and Surfaces A Physicochemical and Engineering Aspects, 241 :323-333, (2004)

Li, P., Ramaswamy, S., Bjegovic, P., "Pre-emptive control of moisture content in paper manufacture using surrogate measurements", Transactions of the Institute of Measurement and Control, 2003, 25, 1, 99, 36-56

Bandyopadhyay, A., Ramarao, B.V., Ramaswamy, S. “Transient moisture diffusion through paperboard materials” Colloids and Surfaces A. Physicochemical and Engineering Aspects (206): 455-467 July 2002

Ramaswamy, S., A. Goel, D. Choi, A. Bandyopadhyay and B. V. Ramarao. “The 3 Dimensional Structure of paper and its relationship to liquid and vapor transport.” In ‘The Science of Papermaking.- Trans. 12th Fundamental Research Symposium’. The Pulp and Paper Fundamental Research Society, Bury, Lancashire BL9 0UF, UK (2001).

Ramaswamy, S., Ryan, M., Huang, S., “Through air drying under commercial conditions” Drying Technology International Journal 19 (10): 2577-2592 (2001)

Ramaswamy, S. Lindsay, J. “Role of Vapor Formation in High Intensity Drying: Description and Comparison of two models” Nordic Pulp and Paper Research Journal vol. 13 (4): 48-58 December (1998)