Taslima Khanam

Three dimensional digital holographic profiling of micro-fibers

A method to measure the size, orientation, and location of opaque micro-fibers using digital holography is presented. The method involves the recording of a digital hologram followed by reconstruction at different depths. A novel combination of automated image analysis and statistical techniques, applied on the intensity of reconstructed digital holograms is used to accurately determine the characteristics of the micro-fibers. The performance of the proposed method is verified with a single fiber of known length and orientation. The potential of the method for measurement of fiber length is further demonstrated through its application to a suspension of fibers in a liquid medium.

On-line digital holographic measurement of size and shape of microparticles for crystallization processes

Crystallization is a widely used chemical process that finds applications in pharmaceutical industries. In an industrial crystallization process, it is not only important to produce pure crystals but also to control the shape and size of the crystals, as they affect the efficiency of downstream processes and the dissolution property of the drug. The effectiveness of control algorithms depend on the availability of on-line, real-time information about these critical properties. In this paper, we investigate the use of lens-less in-line digital holographic microscopy for size and shape measurements for crystallization processes. For this purpose, we use non-crystalline spherical microparticles and carbon fibers with known sizes present in a liquid suspension as test systems. We propose an algorithm to extract size and shape information for a population of microparticles from the experimentally recorded digital holograms. The measurements obtained from the proposed method show good agreement with the corresponding known size and shape of the particles.

Compact digital holographic microscopes and application

Digital Holographic Microscopy (DHM) has shown increased interest over the recent years with applications ranging from MEMS inspection and testing, to Microscopy of cells and also for particle sizing and characterization. Various set-ups have been exploited for these applications. In this paper we describe three of such compact set-ups suitable for each of the above mentioned areas.

Comparison of Image Processing Methods for the Detection of Particle from Digital Hologram

Two image processing methods for the detection of particle based on digital holography are presented and compared. The image processing methods are developed based on edge detection and threshold based segmentation. The proposed methods have been applied on reconstructed images of holograms of ceramic beads and certified microspheres. Particle size distribution obtained for both methods are found to be in good agreement with the actual size, but the processing speed for threshold based detection has found to be faster in compared to the edge detection method.

Ionic Liquid – Assisted Synthesis and Characterization of Cerium Oxide Nanocubes for Degradation of Methylene Blue

Cerium Oxide (CeO2) nanocubes are synthesized by using hydrothermal treatment method in the presence of four different types of ionic liquid such as acetate anion, phosphate anion, and dicyanamide anion. Ceria nanocubes has been consisted with average size of 16 to 31 nm in diameter and characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), and surface analyzer and porosimetry analysis (ASAP). Ceria nanocubes have higher photocatalytical ability in the degradation of methylene blue as compared to commercial ceria nanoparticles which are confirmed through ultraviolet-visible spectroscopy (UV/Vis).