Sergio Mendez, PhD

Chemical Engineering, CSULB

We are devloping a low-cost, portable sensor to screen for type II diabetes.  Electrical and optical circuitry were designed to track chemical reactions of patient salivary samples.  The reaction chamber was fabricated with a 3-D printer.  The chemical reactions were modeled with the COMSOL Multiphysics simulation software.  The students involved in this project used this device to propose a new start-up company at the  CSULB Innovation Challenge.  The goals of this project are to continue refining the electronics of the device, gain a better understanding of salivary chemistry, and to start-up a new biotech company.

We recently purchased both Siemens and Allen-Bradley programmable logic controllers (PLCs).  In addition, we also have National Instruments data acquisition hardware with the LabVIEW programming software.  We have assembled and tested a batch chemical process to extract CBD and essential oils from hemp (Cannabis) plant materials.  This includes process control schemes as well as automation to increase product quality, reduce labor costs and to ensure human safety. This Youtube video describes the automated system.

We have a license for COMSOL Multiphysics finite element software.  We have already modeled many unit operations in the undergraduate Chemical Engineering teaching lab.  The modules utilized so far are chemical reaction engineering, heat transfer, computational fluid dynamcs and (P.I.D.) process control.  Current work is being done to simulate exotic prototypes of heat sinks with the goal of maximizing the heat transfer while minimizing the amount of metal needed.

Chlorofluorohydrocarbons (CFC) refrigerants have been phased out since they have high ozone depletion potential. Their replacements were hydrofluorocarbon (HFC) that have been found to exhibit high global warming potential.  The next generation of refrigerants, therefore, will be blends of low global warming potential refrigerants. We are conducting thermodynamic modeling of such azeotropic, ternary mixtures.

Thermodynamics at the Beach

https://sites.google.com/view/thermo-at-lb/home

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Our goal in this project was to fabricate a green composite material that could potentially be used for building applications.  We intended to make it as green as possible by using mostly plant based materials as well as agricultural waste residues.  The main challenge was getting the polyurethane chemistry to yield foam with optimum mechanical properties.

In a related project, we performed the vacuum infusion lay-up process to make rigid hemp laminates that were utilized for concrete structure reinforcement.

The electrospinning process was used to form co-axial silica/copolymer fibers.  The block copolymer had a fraction that would yield lamellar nanostructure.  The copolymer fibers after thermal annealing exhibited two orientations of lamellae that were affected by the cylindrical confinement. Professor Joo at Cornell was the principal investigator.

Molecular dynamics simulations were performed to model a nanoparticle/copolymer system.  Since the nanoparticle was defined as being selective to one of the copolymer blocks, it was segrated to that region of the lamellar structure.  The effect of shear was also investigated.  This work was done under the guidance of Professors Escobedo and Joo at Cornell University.

Microfluidic flow-focusing devices were utilized to generate monodisperse, nanostructured silica microparticles.  This was done with water-in-oil emulsion.  The aqueous phase contained the chemical precursors that subsequently solidified ex-situ.   This work was done in collaboration with Professor David Weitz from Harvard University.

This project had multiple facets.  There was the synthesis of polymer thin films, the characterization of the thermoresponsive behavior, bacteria adhesion properties, and the theoretical modeling.  There were collaborators from two universities and two national labs.

Theoretical methods as well as Monte Carlo and molecular dynamics simulations were utilized to model the thermodynamics of polymer solutions.  The main goal was to illucidate the effect of explicit solvent on the polymer equilibrium structure.  Dr. John Curro from Sandia National Labs was the principal investigator.