Ratan Boruah

Ambient air quality and emission characteristics in and around a non-recovery type coke oven using high sulphur coal

The objective of this study is to determine the concentrations of gaseous species and aerosols in and around a non-recovery type coke making oven using high sulphur coals. In this paper, physico-chemical properties of the feed coal sample are reported along with the collection and measurement of the emitted gases (SO2, NO2, and NH3) and aerosol particles (PM2.5, PM10) during the coal carbonization in the oven. The coals used are from northeast India and they are high sulphur in nature. The concentrations of the gases e.g., SO2, NO2 and NH3 emitted are observed to be within the limit of National Ambient Air Quality Standard for 24h. The mean PM10 and PM2.5 concentrations are found to be 125.4 μg/m(3) and 48.6 μg/m(3) respectively, as measured during three days of coke oven operations. About 99% of the SO2 in flue gases is captured by using an alkali treatment during the coke oven operation. A Principal Component Analysis (PCA) after Centred Log Ratio (clr) transformation is also performed to know the positive and negative correlation among the coal properties and the emission parameters.

Soy flour nanoparticles for controlled drug delivery: effect of crosslinker and montmorillonite (MMT)

Soy flour (SF)–Montmorillonite (MMT) nanoparticles crosslinked with glutaraldehyde (GA) have been made and used as a carrier for isoniazid. The nanoparticles have been characterized by fourier transmission infra-red spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission emission microscopy (TEM). The effects of MMT and glutaraldehyde on the nanoparticles have been assessed with regard to swelling, encapsulation efficiency and consequently, the release of isoniazid in different mediums. The drug release mechanism has been studied for different time periods by UV-Vis spectroscopy. Cytotoxicity testing has been performed by MTT assay analysis. The results imply that the nanoparticles can be exploited as a potential drug carrier for controlled release applications.

Lycopene coupled ‘trifoliate’ polyaniline nanofibers as multi-functional biomaterial

Bio-conjugation seems to be an unparalleled avenue to tailor the shape-size-bioactivity accord of nanomaterials. In this backdrop, conjugation of tomato peel lycopene through the green chemistry tool of sonication, under statistically optimized parameters led to the morphological alteration of polyaniline (PAni) nanofiber from linear to biomimetic ‘runner’ morphology with trifoliate branching as observed under TEM. X-ray diffractogram was suggestive of alterations in the d-spacing and strain in the polymer backbone post lycopene binding. Post bio-conjugation, the semiconducting-behavior of the PAni nanofibers was retained although lycopene coupling resulted in a decrease in the formers conductivity. DMol3 was employed for the quantum molecular calculations of lycopene interacting with PAni (via non-covalent functionalization involving π–π stacking) and its solvation study. The contribution to HOMO came from the lycopene unit whereas the LUMO had contribution from the aromatic ring of PAni in the conjugated system. The bioactivity of the PAni nanofibers post bio-conjugation was attested by free radical scavenging and anti-lipid peroxidation of liver tissue homogenate. Epiflorescence microscopic imaging demonstrated the cytocompatibility with L929 normal cell line while the nuclear fragmentation and membrane blebbing of apoptotic HeLa cells vouched for the anticancer action of the conjugated system. Furthermore, the reported system exhibited a stimulatory effect on Cucumis sativus seed germination. Thus the study marshals in support of modulated morphology and desirable bio-action of nanoscaled biomaterials via bio-conjugation for advanced applications.

X-ray (Radial Distribution Function, RDF) and FT-IR analysis of high sulphur Tirap (India) coal

AbstractA preliminary study has been performed on high sulphur coals from Tirap colliery of Assam, India, using X-ray (RDF) technique and FT-IR spectroscopy. XRD pattern of the coal shows that it is amorphous in nature. Function of radial distribution analysis (FRDA) indicates that coal is lignite in type and there is no evidence of graphite like structures. The first maximum in the FRDA at R=0·133 nm relates to the C–C aliphatic bond (type C–CH=CH–C), and the second maximum at R=0·25 nm relates to the distance between carbon atoms of aliphatic chains that are located across one carbon atom. The curve intensity profiles obtained from FRDA show quite regular molecular packets for this coal. FT-IR study shows the presence of aliphatic –CH, –CH2 and –CH3 groups, aliphatic C–O–C stretching associated with –OH and –NH stretching vibrations and HCC rocking (single and condensed rings).

One-pot facile green synthesis of biocidal silver nanoparticles

The plant root extract mediated green synthesis method produces monodispersed spherical shape silver nanoparticles (AgNPs) with a size range of 15–30 nm as analyzed by atomic force and transmission electron microscopy. The material showed potent antibacterial and antifungal properties. Synthesized AgNPs display a characteristic surface plasmon resonance peak at 420 nm in UV–Vis spectroscopy. X-ray diffractometer analysis revealed the crystalline and face-centered cubic geometry of in situ prepared AgNPs. Agar well diffusion and a colony forming unit assay demonstrated the potent biocidal activity of AgNPs against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas diminuta and Mycobacterium smegmatis. Intriguingly, the phytosynthesized AgNPs exhibited activity against pathogenic fungi, namely Trichophyton rubrum, Aspergillus versicolor and Candida albicans. Scanning electron microscopy observations indicated morphological changes in the bacterial cells incubated with silver nanoparticles. The genomic DNA isolated from the bacteria was incubated with an increasing concentration of AgNPs and the replication fidelity of 16S rDNA was observed by performing 18 and 35 cycles PCR. The replication efficiency of small (600 bp) and large (1500 bp) DNA fragments in the presence of AgNPs were compromised in a dose-dependent manner. The results suggest that the Thalictrum foliolosum root extract mediated synthesis of AgNPs could be used as a promising antimicrobial agent against clinical pathogens.

Study of Optical and Photovoltaic Properties of N-Alkyl Substituted Polycarbazole Derivative and Its Copolymer with Thiophene

Poly(9-dodecylcarbazole) (PDDC) and poly[(9-dodecylcarbazole)-co-thiophene] (PDDCT) were studied for optical and electrochemical properties and found the polymers as promising material to be used for the solar cell. The electrochemical band gap for the polymers PDDC and PDDCT were calculated to be 2.21 eV and 1.91 eV, respectively. The absorption spectra showed broad absorption over the wavelength range of 350–590 nm with maximum absorptions at 414 and 443 nm (λmax), respectively, for PDDC and PDDCT. The polymeric photovoltaic cells based on blend of polymer and TiO2 nanoparticles were fabricated and the power conversion efficiency (PCE) of the photovoltaic cells were measured to be 0.11% and 0.14%, respectively, for PDDC and PDDCT, and improved the same up to 0.18% and 0.24% upon annealing of the active layer films at 150°C for 30 minutes.

Surface Plasmon Resonance-Based Protein Bio-Sensing Using a Kretschmann Configured Double Prism Arrangement

In this paper, we demonstrate bio-sensing response of bio-medically relevant proteins by employing a surface plasmon resonance (SPR)-based experimental setup that uses a set of double prisms in Kretschmann configuration. The SPR signal of nanoscale Ag-films of varying thicknesses was first monitored experimentally and then verified through computational simulation. The SPR signal was found to be substantially modulated at the metal-dielectric interface when the nanoscale Ag-films are exposed to bio-molecules, such as catalase, papain, bovine serum albumin, trypsin, and lysozyme, which were evaluated independently.

Utilization of two agrowastes for adsorption and removal of methylene blue: kinetics and isotherm studies

Fresh water streams contaminated with synthetic dye-containing effluents pose a threat to aquatic and human life either by preventing aquatic photosynthesis or by entering into the food chain. Adsorptive removal of such dyes with potent biosorbents is an important technique to reduce bioaccumulation and biomagnifications of the dyes in human life. We report use of betel nut (BN) husk and banana peel (BP), two most abundant ligno-cellulosic wastes, as efficient adsorbents for the removal of the basic dye methylene blue (MB). The adsorption by BN and BP was consistently high over wide ranges of pH and temperature, suggesting their dye removal potential in diverse conditions. Physico-chemical studies, e.g. scanning electron microscopy and Fourier transform-infrared spectroscopy studies, revealed changes in surface topology and functional moieties of BN and BP post adsorption, implying dye interaction with the biomass surface. The dye adsorption in both cases followed pseudo-second-order kinetics. While adsorption of MB by BN was better fitted with the Temkin isotherm model, adsorption with BP followed both Langmuir and Freundlich isotherm models. Our studies concluded that both adsorbents efficiently remove MB from its aqueous solution with BP proved to be marginally superior to BN.

Laboratory measurements of the light scattering properties of bentonite clay particles embedded in a cylindrical polymer matrix

The volume scattering function and degree of linear polarization of randomly oriented bentonite clay particles were investigated as a function of scattering angle at 543.5 nm, 594.5 nm and 632.8 nm incident laser wavelengths by using a detector array-incorporated laboratory light scattering setup. Readings were taken in steps of 1° from an angle of 10° to 170° and each detector was separated from the next one by an angle of 10°. A transparent cylindrical polymer matrix made of cycloaliphatic amine-cured thermosetting epoxy resin was used to hold the scattering samples in front of the laser beam. For background correction the measurements were taken in differential mode.

Development of an Internet Web Application for the Study of Surface Plasmon Resonance Spectroscopy

An online web application was developed for the study of surface plasmon resonance (SPR) of different materials using angular and wavelength modulation. The present web application investigates the optical characteristics of the spectral and angular responses of a Kretschmann SPR sensor configuration that is widely applied for biological and chemical sensing by using the characteristic transmission matrix (CTM) method. The accuracy, efficiency, and reliability of the web application were validated by comparing the results generated by using the web application with other benchmark theoretical results and results of SPR experiments with standard samples.