Nanotechnology Engineering

GIOVANNI DE BELLIS

The course introduces the basic principles of rheology and rheometry, both in rotational and oscillatory regime, with a special emphasis on smart fluid, in particular Electro-Rheological ones.

By the end of the course the student will be able to:
- Understand and apply mathematical models underlying the flow behavior of both an ideally viscous and visco-elastc fluid;
- Differentiate fluids, based on their rheological behavior;
- Design and conduct rheometric measurement on materials showing various rheological behavior;
- Understand potential applications of smart fluids in industry;
- Analyze and interpret experimental tests, based on raw data analysis;
- Develop and apply predictive models though software data processing (Matlab).

• Understanding the difference between Newtonian and non-Newtonian fluids;
• Understanding and being able to interpret a flow curve and a viscosity curve;
• Knowing how to interpret the rheological behavior of a material in dynamic regime;
• Understanding and being able to classify electrorheological fluids;
• Being able to prepare a simple electrorheological fluid in the laboratory and characterize it from a rheological point of view

Polarization in dielectrics

Introduction to rheology: ideally viscous fluids and ideally elastic solids. Viscoelasticity. Newtonian and non-Newtonian fluids. Maxwell and Kelvin models. Yield stress. Rheometry: steady state and oscillatory regime measurements. Flow and viscosity curves. Linear viscoelastic region (LVER). Mechanical spectrum. Electrorheological Fluids. The Winslow effect. ER effect of pure liquids. ER effect of colloidal suspensions. Positive, negative, photo and magneto-electrorheological effects. ER materials and applications.
Matlab Environment overview. Variables and built-in constants. Vectors. Matrices. Matrix Indexing. Useful Matrix functions. Plotting. Multiple plots. M-files: Scripts and Functions. Fitting and interpolation. Applications and examples.

Lecture slides

Theoretical lessons and pratical activitisies in the laboratory

Attendance is not compulsory but strongly encouraged, especially as regards laboratory activities

The final exam aims at assessing the level achieved by the student in the acquisition of knowledge and skills, as described in the training objectives.
The evaluation will stem from the examination of two separate tasks:
1) A written report involving the analysis of the topic, the objective, the activity carried out in the laboratory, the results obtained, the discussion of such results, highlighting the personal contribution of the student, in the case of group work;
2) An interview during which the student describes the slides (e.g., a Powerpoint presentation), the contents of the dissertation or of the laboratory report.
The exam is scored on a 0-30 scale, based on the quality of the report, presentation and the answers given to the examiner during the interview.

• What is the difference between the different measurement systems in a rotational rheometer?
• Describe the differences between a GER-type and DER-type electrorheological fluid.
• What are the main mechanical models to describe the viscoelastic behavior of a material?

• Introduction
  to rheology and rheometry. Liquid systems and viscoelastic solids.
  Rheologically relevant parameters: the Deborah number. Ideal models: elastic
  solids and viscous fluids. Rheological parameters in the parallel-plate model:
  shear stress, shear rate, dynamic (absolute) viscosity and kinematic viscosity.
  Fundamental rheological models: Newtonian, Bingham, pseudoplastic
  (shear-thinning), and dilatant (shear-thickening) fluids
  • Books: Lab notes and slides


• Elementary
  mechanical models. Introduction to rheometry and basic geometries. Introduction
  to dynamic tests: purely elastic and purely viscous responses; viscoelastic
  response.
  • Books: Lab notes and slides


• Introduction
  to smart (field‑responsive) fluids. Magnetorheology: principles and main
  operating modes. Electrorheology: definitions. DER and GER electrorheological
  fluids. Polarization models. Application examples.
  • Books: Lab notes and slides


• Introduction
  to the measurement systems used in rotational rheometry. Conversion
  coefficients between instrument parameters (torque, rotational speed, angular
  deflection) and rheological parameters. Rheological measurements. Variation of
  the rheological response of a Newtonian liquid (silicone oil) as a function of
  temperature. First group.
  • Books: Lab notes and slides


• Introduction
  to the measurement systems used in rotational rheometry. Conversion
  coefficients between instrument parameters (torque, rotational speed, angular
  deflection) and rheological parameters. Rheological measurements. Variation of
  the rheological response of a Newtonian liquid (silicone oil) as a function of
  temperature. Second group.
  • Books: Lab notes and slides


• Variation
  of the rheological response of a pseudoplastic liquid (epoxy resin) as a
  function of the concentration of 1D nanostructures (CNF) and dispersion
  quality. Filler concentrations of 0.25 wt%. First group
  • Books: Lab notes and slides


• Variation
  of the rheological response of a pseudoplastic liquid (epoxy resin) as a
  function of the concentration of 1D nanostructures (CNF) and dispersion
  quality. Filler concentrations of 0.25 wt%. Second group
  • Books: Lab notes and slides


• Variation
  of the rheological response of a pseudoplastic liquid (epoxy resin) as a
  function of the concentration of 1D nanostructures (CNF) and dispersion
  quality. Filler concentrations of 0.5 wt%. First group
  • Books: Lab notes and slides


• Variation
  of the rheological response of a pseudoplastic liquid (epoxy resin) as a
  function of the concentration of 1D nanostructures (CNF) and dispersion
  quality. Filler concentrations of 0.5 wt%. Second group
  • Books: Lab notes and slides


• Variation of the rheological response of a pseudoplastic liquid
  (epoxy resin) as a function of the concentration of 1D nanostructures (CNF)
  and dispersion quality. Filler concentration of 1 wt% with variable
  processing time. First group.
  • Books: Lab notes and slides


• Variation
  of the rheological response of a pseudoplastic liquid (epoxy resin) as a
  function of the concentration of 1D nanostructures (CNF) and dispersion
  quality. Filler concentration of 1 wt% with variable processing time. Second
  group.
  • Books: Lab notes and slides


• Variation
  of the rheological response of a dilatant (shear‑thickening) liquid consisting
  of an H₂O/corn‑starch suspension at subcritical (40 wt%) and supercritical (55
  wt%) concentrations, in both rotational and oscillatory modes. First group.
  • Books: Lab notes and slides


• Variation
  of the rheological response of a dilatant (shear‑thickening) liquid consisting
  of an H₂O/corn‑starch suspension at subcritical (40 wt%) and supercritical (55
  wt%) concentrations, in both rotational and oscillatory modes. Second group
  • Books: Lab notes and slides


• Variation
  of the yield stress of an electrorheological fluid as a function of the applied
  external electric field. First group.
  • Books: Lab notes and slides


• Variation
  of the yield stress of an electrorheological fluid as a function of the applied
  external electric field. Second group.
  • Books: Lab notes and slides