  The aqueous magnetic nanofluid consists of superparamagnetic nanoparticles,
with a typical size 10-12 nm. On the application of the magnetic field, these
nanoparticles align heterogeneously and form a chain or chain-like structure.
This structure is observed using a microscope. Although such chain or
microstructure formation is well reported in many articles, the method to
identify and determine chain parameters, e.g., chain length, width, and
associated counts, are scare. Similarly, inter-chain or successive distance is
one of the critical parameters for the development of magnetic nanofluid based
devices. This paper describes Magnetic Field induced Chain Parameters (MFCP)
and Magnetic Field induced Interchain Distance (MFID) a set of new ImageJ
methods to identify and determine (i) chain length, width, and associated
counts, along with (ii) successive distance of the chains respectively in the
magnetic nanofluid. This utilises a macro files such as MFCPji.txt and
MFIDji.txt for ImageJ, which can be used on microscopic image of magnetic
nanofluid without and with application of magnetic field. The method requires
no specialised scientific equipment and can be run entirely using free to
download software. The examples of microstructure formations in two different
magnetic fluids (A & B) are discussed. The results of the associated weighted
average chain width and counts, as well as the successive distance between the
chains, are reported. The chain parameters are useful to determine diffraction
grating angle. The MFCPji and MFIDji macros has been integrated into a macro
tool set that can be configured to be run on ImageJ start up. The MFCPji and
MFIDji are available from the following Uniform Resource Locator (URLs):
https://github.com/urveshsoni/ImageJ -- Macros
https://ruchadesailab.wordpress.com/publication/
