Sudip Dasgupta

Layered Double Hydroxides Based Ceramic Nanocapsules as Reservoir and Carrier of Functional Anions

An extensive study of the intercalation of a number of commercially important anions into a range of layered double hydroxides (LDHs) has been presented. Intercalating anions include key drugs, vitamins, fragrances, dye, etc. The immense potential of LDH systems as reservoirs and carrier of different functional anions was demonstrated. The release of the guest anions was studied in representative conditions.

Bioactive Glass and Biopolymer Based Composite Scaffold for Bone Regeneration

The composite scaffold of chitosan-gelatin reinforced with bioactive glass particles was prepared using freeze drying method after blending chitosan and gelatin solution with bioactive glass where glutaraldehyde acted as a cross-linking agent for biopolymers. Bioactive glass particles were synthesized using sol-gel route and characterized using XRD and FTIR. The composite scaffold was prepared at a fixed solid loading of 30 wt% with a composition of gelatin, chitosan and bioactive glass at 20:50:30 in weight. Characteristic IR band for (–C=N–) bond in the prepared composite scaffold confirmed inter gelatin and chitosan-gelatin cross-linking in the scaffold with the help of glutaraldehyde. Total porosity in the scaffold varied between 75% and 80% as determined by Archimedes principle. Microstructural investigation using scanning electron microscopy revealed well interconnected porosity in the scaffold with pore size in the range of 100–150 μm. Bioactive glass particles were found to be well dispersed in the pore wall of biopolymer matrix. The developed scaffold exhibited an average compressive strength of 2.48 MPa which is close to the lower limit of compressive strength of spongy bone. In vitro bioactivity was assessed after immersing the scaffold in simulated body fluid, with a result indicating an entire coverage of the scaffold with a thick deposition of carbonated apatite after 10 days. MTT assay on the mesenchymal stem cells (MSCs) cultured scaffold showed that the scaffold supported MSCs proliferation up to 7 days of cell culture.

Dispersion Patterns of Suspended Particulate Matters from Furnaces in Glass Industries: Seasonal and Meteorological Effects

The area of the present study covers the glass industries at Firozabad, the glass town, which lies in the pollution sensitive area of Taj trapezium. The objective is to estimate the dispersion of stack emitted particulate matters in different wind-flow conditions (viz. low, average and high turbulent conditions or on calm conditions). Seasonal and meteoro-logical effects on dispersion and the spatial distribution of ground level concentrations were interpreted on the basis of Bosanquet Model of dispersion. A software on IBM PC compatible system has been developed to take care of all the computations concerned and to draw the wind rose and equipollution rose from the base data.

A Rapid Complexometric Method for the Determination of ZnO, Al2O3 and P2O5 in Phosphate-Based Glasses

A rapid complexometric method has been developed for determination of ZnO, Al2O3 and P2O5 in zinc-phosphate glasses. Aluminium and zinc are determined in one aliquot, and P2O5 in another, from the same stock solution. The method is based on the complexation of both the metals with a known amount of EDTA. EDTA is then selectively released from Al-EDTA complex by NaF and titrated. The unreleased EDTA establishes zinc. The determination of phosphorus involves precipitation of phosphate with a known excess of lanthanum solution at 60°–70°C and back titration of the excess with EDTA at pH 5.3, zinc and aluminium being premasked with EDTA. Results obtained with synthetic solutions as well as glass samples following the method are quite agreeable to those obtained by the standard methods.

Stepwise Complexometric Determinations of Calcium and Magnesium in Lime and Magnesia Bearing Materials

A simple and rapid complexometric method for stepwise titration of calcium and magnesium, when present in unfavourable ratios, has been successfully worked out. The method is based on the direct titration of calcium of pH 12 with EDTA, using thymolphthaleincalcein indicator. The adsorption of metallochromic indicator and any Ca2+ has been prevented by the prior addition of titan yellow which masks magnesium by lake formation. Glycerine is also added as a protective colloid to stabilize the lake and to prevent coprecipitation of Ca(OH)2. After dissolution of the lake in HC1 acid, subsequent addition of ascorbic acid, then ammonia and ammonia buffer, for controlling the pH at 10, Mg is determined in the same aliquot by direct titration with EDTA using Eriochrome Black T indicator. The method has been successfully applied for the determination of calcium oxide and magnesium oxide in magnesite, dolomite, asbestos and other lime and magnesia bearing materials.

Stepwise complexometric determination of calcium and magnesium, and manganese in blast furnace slags and manganese minerals

A simple and rapid complexometric method for stepwise titration of Ca and Mg, and Mn in blast furnace slags and manganese minerals has been worked out without involving any separation of manganese. The method is based on the joint titration of Ca and Mg at pH 10 using naptholgreenorthocresolphthalein-ammonium chloride mixed indicator after masking manganese effectively with KCN and bubbling air through the solution (30° -40°C) for 10 minutes. Manganese is then titrated at the same pH in the presence of indicator solution containing eriochrome black T, titan yellow and triethanol amine after reducing the Mn (III) hexacyano complex to Mn (II) cyanide complex with ascorbic acid. Calcium is, however, determined from a separate aliquot by direct titration with EDTA using calcein-thymolphthalein indicator after masking Mn with TEA and K CN. © 1980 Taylor & Francis Group, LLC.

A Scheme for Rapid Analysis of Enamels and Frits

A scheme has been worked out for rapid and accurate analysis of enamels and frits. The scheme enables the determination of seventeen different constituents from a stock solution of single decomposition. The stock solution was prepared by decomposing the sample with hydrofluoric and sulphuric acids. Lead and barium were separated as sulphates prior to the determination of other constituents and then lead sulphate was separated from barium sulphate for the first time with EDTA at pH 4.3. Different aliquots were used for determination of sodium and potassium by flame photometry; cadmium and zinc by polarography and traces of iron, chromium, nickel, copper, cobalt and manganese by spectrophotometry. From another aliquot of the stock solution interfering elements were removed by mercury-cathode electrolysis and then zirconium, aluminium, calcium and magnesium were determined by complexometric methods and titanium by the spectrophotometric or polarographic method. Separate samples were decomposed for determinat...

Review of Small Scale Glass Industries of Firozabad: Problems in Respect of Pollution and Remedial Suggestions

The glass industries of Firozabad have been emitting considerable amount of Suspended Particulate Matters (SPM) and toxic gases into the atmosphere. The main source of these pollutants is inefficient primitive furnaces. The problem was thoroughly investigated in the light of the sources of pollution and their effects on human beings. In this paper, some remedial measures have been suggested to minimize the pollution created by these industries.

An Integrated Scheme for Rapid Analysis of Glass and other Silicate Materials without using Costly Platinum Wares and the Toxic KCN

An integrated scheme for chemical analysis of soda-lime-silica glass and a few other silicate raw materials, having the following significant features, has been developed.(a) Nickel and teflon wares have been introduced in the place of costly platinum articles; (b) interferences due to nickel as contaminant during fusion and silica from the matrix have been overcome by external addition of Al3+ as collector and O-phenanthroline as the masking agent; (c) use of toxic KCN which is invariably used in the common analytical processes has been done away with; and (d) the time and cost of an analysis have been drastically reduced.Following the developed scheme, samples of soda-lime glasses, clays etc have been analysed. The results show a satisfactory conformity with those obtained by standard methods.

Spectrophotometric determination of silver in ceramic water filter candle using dithizone

A spectrophotometric method has been developed for determination of small amounts of silver dopE�d in ceramic water filter candle using dithizone as a chromogenic reagent. The studies revealed that (i) the Amax of the Ag2-dithizonate complex Jay at 570 nm, (ii) the optical density was linear up to 10 ppm of silver, (iii) at pH 10-11 the complex was stable up to 4 hrs, above which it precipitated out, (iv) the alkaline dithizone solution retained its complexing property for a period of 6 hrs and (v) interferences due to AI, Fe, Ti etc were sequistered by adding EDT A and TEA prior to development of colour. Results obtained with the present method agreed well with those obtained by atomic absorption spectrophotometry. © 1985 Taylor & Francis Group, LLC.