# Flow Anisotropy due to Thread-Like Nanoparticle Agglomerations in Dilute Ferrofluids

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## Abstract

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## 1. Introduction

## 2. Materials and Methods

#### 2.1. Overview

#### 2.2. Derivation of Model Predictions

#### 2.3. Experiment

## 3. Results

## 4. Discussion

## 5. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

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**Figure 2.**X-ray, phase-contrast image of magnetized bulk ferrofluid, showing (i) thread-like aggregates aligned with direction of applied uniform magnetic field; and (ii) falling spherical glass ball.

**Figure 3.**Normalized speed vs. angle of the applied field, experimental measurements and model interpolation as in Equation (11): (

**a**) EFH-1 fluid and magnet B; (

**b**) EFH-1 fluid and magnet B; (

**b**) EFH-1 fluid and magnet C; (

**c**) P2XD fluid and magnet C; the value for each configuration is the mean over several repeated “ball-drop” trials in that configuration; the error bars are the standard-deviation from the mean value for the repeated trials in a given configuration.

**Table 1.**Measured magnetoviscosity factor, $\frac{{\eta}_{m}}{{\eta}_{0}}$, and anisotropy factor $\tilde{C}$ for the two applied field strengths (C magnet: 980 G, B magnet: 490 G) and types of ferrofluid (EFH-1, P2XD purified, see text) used in the experiments.

Configuration | $\frac{{\mathit{\eta}}_{\mathit{m}}}{{\mathit{\eta}}_{0}}$ | $\tilde{\mathit{C}}$ |
---|---|---|

EFH-1 with B magnet | 0.76 | 0.58 |

EFH-1 with C magnet | 0 .47 | 1.31 |

P2XD with C magnet | 0.92 | 0.13 |

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**MDPI and ACS Style**

Cali, A.; Lee, W.-K.; Trubatch, A.D.; Yecko, P.
Flow Anisotropy due to Thread-Like Nanoparticle Agglomerations in Dilute Ferrofluids. *Fluids* **2017**, *2*, 67.
https://doi.org/10.3390/fluids2040067

**AMA Style**

Cali A, Lee W-K, Trubatch AD, Yecko P.
Flow Anisotropy due to Thread-Like Nanoparticle Agglomerations in Dilute Ferrofluids. *Fluids*. 2017; 2(4):67.
https://doi.org/10.3390/fluids2040067

**Chicago/Turabian Style**

Cali, Alexander, Wah-Keat Lee, A. David Trubatch, and Philip Yecko.
2017. "Flow Anisotropy due to Thread-Like Nanoparticle Agglomerations in Dilute Ferrofluids" *Fluids* 2, no. 4: 67.
https://doi.org/10.3390/fluids2040067