A. Younus

Investigation on reconstruction methods applied to 3D terahertz computed tomography.

3D terahertz computed tomography has been performed using a monochromatic millimeter wave imaging system coupled with an infrared temperature sensor. Three different reconstruction methods (standard back-projection algorithm and two iterative analysis) have been compared in order to reconstruct large size 3D objects. The quality (intensity, contrast and geometric preservation) of reconstructed cross-sectional images has been discussed together with the optimization of the number of projections. Final demonstration to real-life 3D objects has been processed to illustrate the potential of the reconstruction methods for applied terahertz tomography.

A Review on Preparation, Properties and Applications of Polymeric Nanoparticle-Based Materials

Polymeric nanoparticles (PNPs)-based materials have gained much deliberation due to advancement in polymer science and technology. PNPs are playing an eccentric role in broad spectrum of applications. The importance of these materials lies in idiosyncratic features associated with PNPs. Due to the impact of the materials on nanotechnology; a comprehensive review has been presented here. We covered not only different techniques for the fabrication of PNPs, but also highlighted the properties and parameters involved and enhanced in PNP-based materials. Moreover the worth of PNP-based materials in applications regarding nanocomposites, drug delivery for cancer treatment, and photovoltaic relevance has been discussed. GRAPHICAL ABSTRACT

Terahertz tomographic imaging of XVIIIth Dynasty Egyptian sealed pottery

A monochromatic millimeter-wave imaging system coupled with an infrared temperature sensor has been used to investigate historic objects preserved at the Museum of Aquitaine (France). In particular, two-dimensional and three-dimensional analyses have been performed in order to reveal the internal structure of nearly 3500-year-old sealed Egyptian jars.

Polymer/Graphite Nanocomposites: Physical Features, Fabrication and Current Relevance

Advancement from graphite to functional polymer/graphite nanocomposite is presented in this review article. These materials are comprised of graphite as filler, i.e., carbon-based thermodynamically stable, pseudo–-two-dimensional (2D), planar and layered solid material. Graphite and its modified forms propose unique properties to composites as high surface area, thermal and electrical conductivity as well as mechanical and barrier properties compared to neat polymers. Fine dispersion of graphitic fillers depends on selection of the appropriate fabrication technique including solution mixing; melt blending and in-situ polymerization. The corresponding significance of polymer/graphite-based nanomaterials, challenges, exploitation and future aspects of the materials is overviewed. GRAPHICAL ABSTRACT

Novel Hybrids of Polystyrene Nanoparticles and Silica Nanoparticles-Grafted-Graphite Via Modified Technique

We have designed polystyrene nanoparticles through modified nanoprecipitation cosolvent evaporation technique and conventional nanoprecipitation and solvent evaporation. Polystyrene nanoparticles were embedded with silica nanoparticles and graphite to analyze scope of nanoprecipitation cosolvent evaporation. Ultraviolet–visible spectroscopic revealed decreased band gap of polystyrene nanoparticles obtained via nanoprecipitation cosolvent evaporation. Scanning electron microscopic showed uniform morphology of polystyrene nanoparticles and polystyrene nanoparticles-based nanocomposites engendered by nanoprecipitation cosolvent evaporation. X-ray diffraction disclosed presence of crystalline domains due to silica nanoparticles content in amorphous structure. Glass transition temperature was increased from 94 (polystyrene) to 124°C (PSNPs/SiNPs 0.6) and 137°C (PSNPs/SiNPs/G 0.6) with filler loading. Electrical conductivity of PSNPs/SiNPs/G 0.6 was also found to be higher (1.53 S/cm). GRAPHICAL ABSTRACT

Terahertz-pulse imaging for non-destructive analysis of layered art paintings

Terahertz-pulsed imaging is employed to reveal primary graphite sketches covered with multiple layers of paintings. Buried layer information, such as handmade sketches drawn with pencil leads were identified by both reflection and transmission 2D imaging.

A Continuous Millimeter-Wave Imaging Scanner for Art Conservation Science

A monochromatic continuous millimeter-wave imaging system coupled with an infrared temperature sensor has been used to investigate artistic objects such as painting artworks or antiquities preserved at the museum of Aquitaine. Especially, 2D and 3D analyses have been performed in order to reveal the internal structure of a nearly 3500-year-old sealed Egyptian jar.

Non-destructive inspection of opaque objects with a 3D millimeter-wave tomographic scanner

Flexible monochromatic millimeter wave system coupled with an infrared temperature sensor demonstrates large size 3D visualization of manufactured opaque phantoms with different refractive index contrasts. Peculiarities such as boundary effects, refraction and diffraction losses will be discussed.

Consideration of refraction losses for time-domain terahertz computed tomography

Terahertz computed tomography has been performed using a time-domain terahertz spectrometer. Refraction losses induced by the transmission of the terahertz radiation through the samples have been taken into account in order to reconstruct the three-dimensional aspect of complex shape objects.

Millimeter continuous wave imaging for non-destructive investigation of artistic materials

A monochromatic millimeter wave system coupled with an infrared temperature sensor has been used to investigate pictorial artworks. The flexibility of the system makes it possible to rapidly reveal buried layer information such as a graphite handmade sketch covered by paintings.