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A novel conductive nano material, nano spinel ferrites having the composition of calcium chromium magnesium nanoferrites (CaxCr0.5−xMg0.5Fe2O4), was fabricated via sol-gel auto combustion process. The main objective was to fabricate highly stable nanocomposite as conductive material. Reaction among highly pure grade magnesium nitrate Mg (NO3)2·6H2O, calcium nitrate Ca (NO3)2·4H2O, and chromium nitrate Cr (NO3)3·9H2O, ferric nitrate Fe (NO3)3·9H2O took place to fabricate the desired material and, later on, an inductance (L)—capacitance (C)—resistance (R) meter (LCR meter) was used to determine the conductive behavior of the material. During characterization, thermogravimetric study confirmed that the stable phase was obtained above 950 °C. Fabricated ferrite FTIR spectrum was observed between 400 cm−1 and 4,500 cm−1. The entire sample’s structural investigation was carried out employing X-ray diffraction. Morphological analysis confirmed that particles possess angular structures having acute angles adjoining surfaces. During conductivity test, all fabricated nanoferrites presented that with the increase of frequency by LCR meter, AC conductivity had been increased. The outcome of doping of calcium on chromium magnesium nanoferrites on structural in addition to dielectric properties was synergistic.

The effects of Mg ion doping on the cobalt-based spinel ferrites nanoparticles synthesized via sol–gel auto-combustion method have been investigated. Dopant concentration values varied in Bi0.2MgxCo0.8−xFe2O4 at x = 0.0, 0.15, 0.35, 0.55, 0.7 and 0.8, respectively. The variation of Mg-Co substitution has a significant effect on the structural, morphological, thermal, electrical and dielectric properties of BiMgCo nanoferrites. The dielectric constant, quality factor, loss coefficient of the material, AC conductivity and its resistivity were studied as a function of increasing frequency in the range of 100 Hz–50 MHz at room temperature. The results are evident of normal behavior of ferrites. Inhomogeneous patterns are observed for all dielectric parameters at lower frequency range but remain constant at high frequencies. This leads to utilize the synthesized material, i.e., BiMgCo nanoferrites for applications in high frequency devices.

Emission tomographic image reconstruction is an ill-posed problem due to limited and noisy data and various image-degrading effects affecting the data and leads to noisy reconstructions. Explicit regularization, through iterative reconstruction methods, is considered better to compensate for reconstruction-based noise. Local smoothing and edge-preserving regularization methods can reduce reconstruction-based noise. However, these methods produce overly smoothed images or blocky artefacts in the final image because they can only exploit local image properties. Recently, non-local regularization techniques have been introduced, to overcome these problems, by incorporating geometrical global continuity and connectivity present in the objective image. These techniques can overcome drawbacks of local regularization methods; however, they also have certain limitations, such as choice of the regularization function, neighbourhood size or calibration of several empirical parameters involved. This work compares different local and non-local regularization techniques used in emission tomographic imaging in general and emission computed tomography in specific for improved quality of the resultant images.