S. K. Mehta

Microemulsions: Thermodynamic and Dynamic Properties

Mixing two immiscible liquids (such as oil and water) using emulsifier and energy inputs has been the matter of study for decades. In early 1890’s extensive work have been carried out on macroemulsions (i.e. oil dispersed in water in the form of fine droplets or vice versa) (Becher, 1977) and several theories and methods of their formation have been vastly explored (Lissant 1976 and 1984). However going along the line, microemulsion systems were well opted because of their stability and isotropic nature. Microemulsions are basically thermodynamically stable, isotropically clear dispersions of two immiscible liquids such as oil and water stabilized by the interfacial film of any surfactant and/or cosurfactant. Although a microemulsion is macroscopically homogeneous, or quasi-homogeneous but structured microscopically. Microemulsions in comparison to micellar systems are superior in terms of solubilization potential and thermodynamic stability and offers advantages over unstable dispersions, such as emulsions and suspensions, since they are manufactured with little energy input (heat, mixing) and have a long shelf life (Constantinides, 1995). The term “microemulsion” was first coined by Schulman group (Schulman et al., 1959). However, ambiguity in the microemulsion terminology persists till today as some authors differentiate them from swollen micelles (which either contain low volume fraction of water and oil) and transparent emulsions (Prince, 1977, Malcolmson et al., 1998). One of the unique factors associated with microemulsions is the presence of different textures such as oil droplets in water, water droplets in oil, bicontinuous, lamellar mixtures etc., which are formed by altering the curvature of interface with the help of different factors such as salinity, temperature, etc. Such a variety in structure of microemulsion is a function of composition of the system. Phase study greatly helps to elucidate different phases that exist in the region depending upon the composition ratios. One peculiarity of microemulsions lies in the fact that these structures are interchangeable. Construction of phase diagram enables determination of aqueous dilutability and range of compositions that form a monophasic region (Fig. 1). One of the unique factor associated with microemulsions is the presence of different structures as classified by Winsor (Winsor, 1948). Winsor I (o/w), Winsor II (w/o), Winsor III (bicontinuous or middle phase microemulsion) and Winsor IV systems are formed by altering the curvature of interface with the help of different factors such as salinity, temperature, etc. Where Type I indicates

Multifaceted Approach for the Fabrication of Metallomicelles and Metallic Nanoparticles Using Solvophobic Bisdodecylaminepalladium (II) Chloride as Precursor

A one-pot synthesis of solvophobic bisdodecylaminepalladium(II) chloride (complex 1) was performed. Complex 1 was characterized using X-ray crystallography and other techniques, namely, mass spectrometry, Fourier transform infrared, NMR, elemental analysis, etc. A multifaceted approach was taken to explore the potential applications of complex 1. The micellization ability of complex 1 was estimated using conductivity method in n-alcohols. The metallomicelles are formed in alcohols, and the process is thermodynamically spontaneous in nature. Using complex 1 as precursor, palladium (Pd) nanoparticles were fabricated using two-phase redox method, where reduction is being performed in core of metallomicelles formed by complex 1 in dichloromethane (DCM). The micellization in DCM is confirmed by small-angle X-ray scattering (SAXS). The SAXS measurements reveal that the micellar of core 4-5 nm is being formed, which further controls the size of nanoparticle. This approach was advantageous in terms of size control, methodology, and yield. Pd nanoparticles were characterized using transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and UV-visible spectroscopy and were also screened for bovine serum albumin interactions. Complex 1 and Pd nanoparticles were found to possess antimicrobial property with broad spectrum and are active against bacteria and fungi. The cytotoxicity analyses were performed over healthy cells (Vero cell lines extracted from kidney of green monkey), and the results reveal IC50 value of 10 μg/mL for complex 1.

Surfactant Coated Silica Nanoparticles as Smart Scavengers for Adsorptive Removal of Naphthalene

This manuscript represents the synthesis of silica nanoparticles modified with four different types of cationic surfactants. The surfactant capped nanoparticles have better control over the size of silica nanoparticles. The as formed as model nanomaterials were used for the removal of naphthalene, a simple white crystalline polycyclic aromatic hydrocarbon (PAH) from aqueous media. The obtained materials were characterized by various microscopic and spectroscopic techniques. The average particle size of nanoparticles was approximately between 50 and 75 nm. The removal kinetic and adsorption studies were also conducted on silica nanoparticles with different contact time, initial concentrations of silica and naphthalene to achieve the optimum adsorption conditions. CPB functionalized nanoparticles have displayed higher removal efficiency of more than 85% as compared to 75 to 80% in case of CTAB, CTAC and CPC functionalized silica nanoparticles. The effects of various parameters like pH, adsorbent doses, naphthalene concentration and addition of salt have also been investigated for better understanding of the removal efficacy of prepared nanoparticles.

A Discourse Linking Tool for English Language Texts comprising Lexicon building and Ontology Creation

Natural Language text is not bound by a fixed structure. For a machine to understand the language, the challenge lies in resolving the ambiguities and capturing innovativeness. Due to its unstructured nature, discourse linking, required for understanding and generating text by a machine is a challenging task. Also, dealing with sentences varied in nature and changing them into generic structure is an additional challenge. This paper presents a way to create a discourse linking tool for English language. This tool is based on specially created lexicon and hand-crafted rules suited for discourse linking purpose. Currently available lexicons such as dictionaries, WordNet, etc. are not suited as they lack domain knowledge. Therefore, an ontology is developed for political news domain which serves as a lexicon and its inherent relations are used for discourse linking purpose.

Bilingual data extraction and auto summarisation

Text Extraction plays an important role in finding valuable information. As a result of rapid growth of available multimedia documents on web and increasing requirement for information, identification, indexing and retrieval, several research have been done on text extraction. Here, a methodology to build a system for text extraction has been presented that is designed to provide support to the applications like Natural Language Processing that requires the data to be in specific format. The data from various formats is extracted and is easily exported to a database. So this tool will be highly useful for creation of data repository and data bank. Also, to speed up the extraction from large size files, research was done and so, large size files are split into small size chunks and efficient use of parallel processing is done to provide faster results. Along with that, Bilingual support is provided, i.e., files of both English and Hindi language can be easily extracted, building respective data banks. Keywords are the important terms, sometimes called, index terms that contain some kind of valuable information about the document. Automatic keyword extraction is the task to identify a small set of words, which can be designated as keywords for that document, and thus provide a brief idea about the document. An effective Keyword Extraction technique has been discussed that can be applied to extract keywords effectively, that uniquely identify a document. A summary is a shortened version of a text of the document that describes the main points of the original document in brief. Automatic summarisation is the task of generating a summary of any input document by the computer. This summary can be used instead for reading the whole content/text resulting in particularly interested.

The Perceived Preferences and Priority Pattern of Farm Graduates towards Higher Agricultural Education Vis-À-Vis Employment

Abstract The study was conducted on the final year students of College of Agriculture, CCS HAU, Hisar to ascertain their preference pattern for specialization in higher agricultural education and their priority pattern for employment. There were 86 students in all, of which 44 students were from 4-year programme and 42 students were from 5-year programme. The study revealed that the 4-year Agriculture stream graduates ranked Agronomyat the top followed by Horticulture, Entomology, Plant Breedingand Extension Educationat 2nd, 3rd, 4th and 5th, respectively. Nematologywas the least preferred subject and Agricultural Meteorologywas the least but one. The 6 year Agriculture programme graduates ranked Agronomyagain at the top followed by Plant Breeding, Entomology, Extension Educationand Horticulture. The first five subjects preferred for higher agricultural education are identical with minor differences in ranking, maintaining Agronomyat the top. Regarding job areas, Civil/Administrative jobs remained the first choice of 4-year programme final year students of college of Agriculture followed by Educational and Research Institutional jobs, State Govt. Jobs, Agro based public sector, Agro-based private sectorand Self employment, while , General jobsand Farmingwere the least preferred job areas. The same priority pattern was observed among 6-year programme students except that they preferred State govt. jobsover Educational and Research Institutional jobs.