Electrochemical copolymerization of thiophene derivatives; a precursor to photovoltaic devices

This work presents an electrochemical technique for the polymerization and copolymerization of thiophene derivatives like 7,9-dithiophene-2yl-8H-cyclopenta[a]acenaphthalene-8-one and 3-hexylthiophene. The structural characterization of chemically synthesized monomers and electrochemically synthesized polymers was carried out by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Thermal characterizations indicate that copolymer has increased thermal stability than that of homopolymer. Morphological studies of the polymerized films carried out by scanning electron microscopy shows network structure of copolymer. Optical properties of the homopolymers and copolymer were studied by UV–visible spectrometer and it was observed that band gap of copolymer is less than the homopolymers. HOMO and LUMO levels, band gap values of the respective polymers were also calculated from the cyclic voltammetry technique with various scan rates. By the peak current obtained from various scan rates shows that all polymerization reactions are diffusion controlled process. Charge transfer resistances of polymers were determined using Nyquist plots. Conductivity of synthesized polymers shows higher conductivity for copolymer than homopolymers.     

Motion tracking system in video based on extensive feature set

In recent years, object detection and tracking has been a dynamic research area. Rapid development of the multimedia and the associated technologies urge the processing of a huge database of video clips. The processing efficiency lies on the search methodologies utilised in the video processing system. Usage of unsuitable search methodologies may make the processing system ineffective. Hence, effective object detection and tracking system is an essential criterion for searching relevant videos from a huge collection of videos. This paper proposes a unique object detection and tracking system where video segmentation, feature extraction, object detection and tracking are combined perfectly using various features. Initially, the database video clips are segmented into different shots before performing the feature extraction process. The proposed system consists of two stages, namely, feature extraction and tracking of object in the video clips. In the feature extraction stage, firstly, colour feature is extracted based on colour quantisation. Next, edge density feature is extracted for the objects present in the query video. Then, the texture feature is extracted based on LGXP technique. Finally, based on these feature extracted, the object will be detected and the detected objects will be tracked by utilising both forward and backward tracking technique. The proposed methodology proved to be more effective and accurate in object detection and tracking.     

Morphological operation and scaled Réyni entropy based approach for masses detection in mammograms

Multimedia Tools and Applications - Detection of suspicious masses in mammograms play a vital role in early diagnosis of breast cancer, to reduce the death rate among women. The presence of masses...     

D–A–D-structured conducting polymer-modified electrodes for detection of lead(II) ions in water

Donor–acceptor–donor-structured thiophene derivative-based conducting polymer poly(7,9-dithiophene-2yl-8H-cyclopenta[a]acenaphthalene-8-one) was chemically synthesized. This polymer was used to modify both glassy-carbon and carbon-paste electrode, which was used to detect lead(II) ions present in water in the range of 1 mM to 0.1 μM. Cyclic voltammetry confirms the formation of the co-ordination complex between the soft segment of polymer and the dissolved lead ion. Anodic stripping voltammetry was carried out by the modified electrode to determine the lower limit of detection of dissolved lead(II) species in the solution. Differential adsorptive stripping and impedance measurements were also conducted to find the lowest possible response of the as-synthesized polymer to lead(II) ion in water. The electrochemical performance of the modified electrodes at different pH (4, 7 and 9) environments was carried out by stripping voltammetry, to get optimum sensitivity and stability under these conditions. Finally, interference analysis was carried out to detect the modified electrode’s sensitivity towards lead ion affinity in water.     

Crystalline and amorphous PEO based ceramic coatings on AA6061: Nanoindentation and corrosion studies

Present study reports the detailed nanomechanical and corrosion behaviours of crystalline and amorphous plasma electrolytic oxidation (PEO) coatings developed on Aluminium alloy-6061. The concentration of sodium silicate in the electrolyte is tailored to achieve crystalline and amorphous natures of the PEO coatings. X-ray diffraction (XRD), scanning electron microscopy (SEM) and nanoprofilometry techniques are utilized to investigate microstructural and morphological properties of the PEO coatings. XRD studies confirmed that crystalline ceramic phases are obtained at lower silicate concentration while amorphous nature occurred for comparatively higher concentration of silicate in the electrolyte. Nanoindentation technique is utilized to study the mechanical properties such as hardness (H) and Young's modulus (E) of the PEO coatings. The scatter of the data is treated with well-established Weibull statistical method. Finally, in depth corrosion behaviour of the coatings are investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. Amorphous coatings exhibited superior mechanical properties compared to the crystalline coatings. This is possibly linked with the presence of aluminosilicate phases and difference in silicon content in the coatings. However, as expected crystalline PEO coatings offer better corrosion resistance than the amorphous coatings and this behaviour is explained in terms of porosity contents of the coatings.     

Effect of different polysorbates on development of self-microemulsifying drug delivery systems using medium chain lipids

The primary objective of this study was to develop lipid-based self-microemulsifying drug delivery systems (SMEDDS) without using any organic cosolvents that would spontaneously form microemulsions upon dilution with water. Cosolvents were avoided to prevent possible precipitation of drug upon dilution and other stability issues. Different polysorbates, namely, Tween 20, Tween 40, Tween 60, and Tween 80, were used as surfactants, and Captex 355 EP/NF (glycerol tricaprylate/caprate) or its 1:1 mixture with Capmul MCM NF (glycerol monocaprylocaprate) were used as lipids. Captex 355-Tween-water ternary phase diagrams showed that oil-in-water microemulsions were formed only when the surfactant content was high (80–90%) and the lipid content low (10–20%). Thus, mixtures of Tweens with Captex 355 alone were not suitable to prepare SMEDDS with substantial lipid contents. However, when Captex 355 was replaced with the 1:1 mixture of Captex 355 and Capmul MCM, clear isotropic microemulsion regions in phase diagrams with sizes in the increasing order of Tween 20?相似文献   

Magnetized CNTs incorporated MBA cross-linked guar gum nano-composite for methylene blue dye removal

In the present work, a magnetized multiwalled carbon nanotube dispersed in chemically cross-linked gaur gum was developed as a nano-composite adsorbent material for the removal of dye from wastewater. The gaur gum, a bio-macromolecule was chemically modified by cross-linking with methylene bis-acrylamide in the presence of sodium hydroxide as a novel approach to prepare the gel matrix. The magnetite nanoparticles loaded multiwalled carbon nanotubes were dispersed in methylene bis-acrylamide cross-linked gaur gum gel during gelation. The nano-composite was characterized for morphological, spectral, and analytical data. The solid form of the nano-composite was evaluated as an adsorbent material for the treatment of water containing methylene blue dye molecules as pollutants by the spectrophotometric method. Adsorption isotherm studies suggested that the Freundlich model was the befitting model for adsorption, indicating the multilayered adsorption and the kinetic study revealed the adsorption to occur by a pseudo-second-order kinetic process. The novel nano-composite is found to be a promising material for the adsorptive removal of dye molecules from dye-contaminated wastewater. The adsorption capacity was observed to be 11 mg/g of the material.