Bryan Torres Maldonado

I was a PhD student at the University of Pennsylvania in the Mechanical Engineering and Applied Mechanics. I was advised by Prof. Arratia (Penn Complex Fluids Lab). My research objective was to understand how microorganisms affects the sedimentation of passive particles. Prior to starting at Penn, I worked in pharmaceutical industry and a medical device industry as an intern. I graduated with a Bachelor of Science degree in mechanical engineering from University of Puerto Rico Mayaguez campus in 2017.



  1. Sedimentation of particles in presence of microorganisms, we investigate the dynamics of the sedimentation of spherical colloids at various E. coli concentration within the dilute regime.
  2. Bacteria tumbling in presence of polymers, we investigate how the presence of polymer affect the dynamics of swimming microorganisms, such as the tumbling frequency of E. coli.
  3. Oscillatory microfluidic rheometer (OMFR), Oscillatory rheology plays an essential role to understand many fluids of practical interest, such fluids are known as complex fluids.  Here, we are developing a method that can accurately measure material properties of complex fluids at frequency and stresses ranges that overcome the capabilities of commercial rheometers.

Previous Experience

  • Quality Assurance Intern, Lilly del Caribe, PR, 2016
  • Undergraduate researcher, UPenn, PA, 2016
  • Manufacturing Engineer Intern, Medtronic, PR, 2014-2015
  • Reliability Engineer Intern, Johnson Controls, PR, 2014


  • Bryan O. Torres Maldonado, K. L. Galloway, Quentin Brosseau, and Paulo E. Arratia, “Phase-separation during sedimentation of dilute bacterial suspensions”, In revision, (2021).
  • Jaspreet Singh, Alison E. Patteson, Bryan O. Torres Maldonado, Prashant K. Purohit, and Paulo E. Arratia, “Bacterial activity hinders particle sedimentation”, Soft Matter, (2021).
  • Somayeh Farhadi, Sergio Machaca, Justin Aird, Bryan O. Torres Maldonado, Stanley Davis, Paulo E. Arratia, and Douglas J. Durian, “Dynamics and Thermodynamics of Air-Driven Active Spinners” Soft Matter, 14, 5588-5594, (2018).


  • Sedimentation of passive particles in the presence of swimming microorganisms, 73rd Annual Meeting of the APS Division of Fluid Dynamics (DFD) virtual meeting, Chicago, Illinois, Nov. 2020
  • Sedimentation of passive particles in the presence of swimming microorganisms, 11th Northeastern Complex Fluids & Soft Matter Workshop (NCS11), New Jersey Institute of Technology (NJIT), Newark, New Jersey, May 2019

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