A portable and affordable extensional rheometer for field testing

Hallmark, Bart; Bryan, MP; Bosson, Ed; Butler, Simon; Hoier, Tom; Magens, Ole; Pistre, Nicolas; Pratt, Lee; Ward, Betsy-Ann; Wibberley, Sam; Wilson, D.I.

doi:10.1088/0957-0233/27/12/125302

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…The extensional rheology was characterised using a Sey.mour extensional rheometer constructed in house based on previous designs. [45,46] The slurry was loaded to 1.9 mm plates with a separation of 0.5 mm, which was rapidly moved to 5 mm in ~0.005 s. The filament was imaged and the time between the end of the strike and the break-up of the filament measured using inhouse MATLAB code, averaged over 3 repeats.…”

Section: Rheologymentioning

confidence: 99%

Impact of Formulation and Slurry Properties on Lithium‐ion Electrode Manufacturing

Reynolds,

Faraji Niri,

Hidalgo

et al. 2023

Batteries & Supercaps

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The characteristics and performance of lithium‐ion batteries typically rely on the precise combination of materials in their component electrodes. Understanding the impact of this formulation and the interdependencies between each component is critical in optimising cell performance. Such optimisation is difficult as the cost and effort for the myriad of possible combinations is too high. This problem is addressed by combining a design of experiments (DoE) and advanced statistical machine learning approach with comprehensive experimental characterisation of electrode slurries and coatings. An industry relevant graphite anode system is used, and with the aid of DoE, less than 30 experiments are defined to map impact of different weight fractions of active material (80–96 wt%), conductive additive (Carbon Black at 1–10 wt%) and a two‐component binder system (Carboxymethyl Cellulose (CMC) at 1–3 wt% and Styrene Butadiene Rubber (SBR), at 1–7 wt%). Using Explainable Machine Learning (XML) methods, correlations between the formulation, slurry weight percentage (30–50 wt% in water) and coating speed (1–15 m/min) are quantified. Slurry viscosity, while known to depend on the CMC concentration, is also heavily influenced by carbon black and SBR when at high concentration, as is common in research. Viscosity increasing components also improve adhesion, by improving dispersion and hindering binder migration. Conductivity of the coating on current collector is sensitive to the current collector‐coating interface, which makes it a highly useful probe. Improvements in cell capacity are observed with higher viscosity formulations (High weight percentage, CMC content), attributed to reduction in migration and slumping of the slurry on the current collector. SBR had a negative impact at any concentration due to its insulating nature, and carbon black reduces gravimetric capacity when included at high concentrations. The insights from this study facilitate the formulation optimisation of electrodes providing improved slurry design rules for future high performance electrode manufacturing.

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Section: Rheologymentioning

confidence: 99%

Impact of Formulation and Slurry Properties on Lithium‐ion Electrode Manufacturing

Reynolds,

Faraji Niri,

Hidalgo

et al. 2023

Batteries & Supercaps

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“…Recently, many novel techniques have been developed to bring the fields of engineering and medicine closer together through measurements, diagnostic tools, and biomimetic inspiration [15]. The current engineering methods investigating bolus rheology, such as novel extensional and couette flow rheometers [16,17], lead to complementary understandings of material flow and deformation. There has been an exploration of new sensation methods of rheology such as ultrasound velocimetry [18].…”

Section: Soft-robotic Esophageal Swallowing As a Clinically-inspired ...mentioning

confidence: 99%

Soft-robotic esophageal swallowing as a clinically-inspired bolus rheometry technique

Dirven

Allen

Wang

et al. 2017

Meas. Sci. Technol.

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To investigate the impact of viscosity and peristaltic transport parameters on manometric pressure signatures, a reproducible swallowing process is required. Due to inter- and intra-subject variability from swallow to swallow, the human body does not represent an optimal mechanism for such an investigation. A smooth and continuous swallowing soft-robot has been developed to produce biomimetic swallowing trajectories, and is proposed to operate as a bench-top bolus rheometric investigation method. The method compares conventional viscometry and pressure signature findings from robotic swallowing experiments. The robotic aspect of experimentation involved 450 biomimetic swallows (10 repetitions of 45 unique experiments). The method examined swallowing transport in three dimensions: bolus formulation, peristaltic wavelength, and peristaltic velocity, each of which are known to contribute to safe and effective swallowing in vivo. It is found that the pressure gradients and magnitudes are commensurate with clinical reports on biological swallowing, on the order of 100 mmHg peak, however, the relationship between viscosity and pressure signatures is less clear. Bolus transport cannot be predicted as a function of bolus viscosity alone. Traditional viscometric data at 50 s−1, as used in clinical practice, may not be a strong indicator of swallow effort, safety, or efficacy in vivo.

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“…Advances in imaging technology mean that these portable versions of these devices can be constructed at reasonable cost. 2 Care needs to be taken in making rheometrical measurements, as the behaviour of a non-Newtonian sample can be influenced by how it was loaded into the device. Care also needs to be taken in interpreting the measurements, particularly with suspensions which may be subject to the phenomenon of wall slip.…”

Section: Rheometrical Measurementsmentioning

confidence: 99%