Ecoprint: An International Journal of Ecology, 2009
In the present paper 10 Cyanophycean algae belonging 10 genera have been described from eastern U... more In the present paper 10 Cyanophycean algae belonging 10 genera have been described from eastern U.P. The genera described are: Chroococcus, Microcystis, Aphanothece, Arthrospira, Spirulina, Lyngbya, Anabaena, Rivularia, and Gloeotrichia. All these forms are being reported for the first time from eastern U.P., India.doi: 10.3126/eco.v13i0.1627Key words: Cyanophycean algaeEcoprint (An International Journal of Ecology) Vol. 13, No. 1, 2006 Page: 35-39
The present work describes the statistical process optimization of a lowcost production process o... more The present work describes the statistical process optimization of a lowcost production process of PLA using organometallic (stannous octoate) compounds. The process optimization for both lactide and polylactide, was developed by factorial design and response surface methodology. The influence of different experimental parameters such as reaction temperature, time, concentration of catalyst and co-initiator concentration on the yield of lactide and polylactide has been evaluated. There are many studies reported on the synthesis of polylactide but no earlier study exists for the application of statistical analysis in determining the interactions among the process variables for lactide and polylactide production. Central composite experimental design with multiple linear regression has been used to estimate the coefficients of the polynomial model equation for the yield(s) of both lactide and polylactide. The statistical significance of polynomial model equation was validated by F test (ANOVA). Determination coefficient (R 2 ) values found to be 0.913 and 0.958 for lactide and polylactide respectively, states that predicted values were in good agreement with the experimental values. Results of the statistical analysis showed that the model fits in all cases. Above synthesised polymer was characterized by FT-IR, 1 H-NMR, DSC and GPC to confirm the polymer structure and properties.
The synthesis and characterization of Th-MCM-41 and U-MCM-41 new members of a growing family of h... more The synthesis and characterization of Th-MCM-41 and U-MCM-41 new members of a growing family of hexagonal packed metallo-silicates molecular sieves are described. The synthesis of these materials was achieved by a “liquid ...
In this study, chitosan/polylactide (CP) blend solutions in trifluoroacetic acid as a co-solvent ... more In this study, chitosan/polylactide (CP) blend solutions in trifluoroacetic acid as a co-solvent with different blend ratio were electrospun. Effects of different CP ratio and process parameters on the diameter of electrospun nanofibers were experimentally investigated. The fiber morphology and the distribution of fiber diameter were investigated by scanning electron microscopy. Response surface methodology (RSM) was used to define and evaluate a quantitative relationship between electrospinning parameters, average fiber diameters and its distribution for each chitosan-polylactide ratio. Applied voltage and polymer solution extrusion rate are the process variables which control the fiber diameter at similar spinning distances (15 cm). Fiber diameter was correlated to these variables by using a second-order polynomial function. The fibers were of diameter ranging from 94 to 389 nm. The predicted fiber diameters were in good agreement with the experimental results. Contour plots were obtained to identify the processing variables suitable for producing nanofibers. It was concluded that ratio of polylactide and chitosan in the blend polymer played an important role to the diameter of fibers and standard deviation of fiber diameter. The processing factors were found statistically significant in the production of nanofibers.
Performance of ultrasound assisted extraction (UAE) technique for the extraction of colourant fro... more Performance of ultrasound assisted extraction (UAE) technique for the extraction of colourant from Dahlia variabilis has been compared with conventional solvent extraction method. It is observed that UAE is more efficient process as compared to solvent extraction. The extracted dye is also characterized by FTIR and UV spectrophotometer. Change in colour with pH of extracted dye is observed due to bathochromic shift from blue green (pH 8.9) to deep red (pH 2.0). The extracted dye is also used for dyeing of wool yarns, generally used in the carpet industries. Good fastness properties of dyed yarn confirm its utility in the textile industries for eco-dyeing. The extracted dye also shows good potential to replace phenolphthalein as an indicator.
Ultrafiltration (UF) membranes were prepared by blending different proportion of polyvinylidene f... more Ultrafiltration (UF) membranes were prepared by blending different proportion of polyvinylidene fluoride (PVDF), sulphonated polyethersulphone (SPES) and nanoparticles of zirconium oxide (ZrO 2 ). The functional groups, surface and cross-sectional morphologies were analysed using Fourier transform infrared, scanning electron microscopy (SEM) and X-ray diffraction, respectively. The presence of particles and pores in the membrane is clearly revealed from the SEM photomicrographs. The effect of different transmembrane pressures is studied to evaluate the performance of membranes. The best value of the permeate flux with a low fouling recovery ratio is obtained at a transmembrane pressure of 0.3 MPa (3 bars). The performance of the membranes having 4 wt% ZrO 2 nanoparticles was studied with and without backwash. The backwashing is capable of restoring the initial flux to about 90%. SPES and ZrO 2 particles were found to play the role of antifouling agent and the hydrophilicity enhancer in the prepared composite membrane.
: Comparative study of dye degradation using TiO 2 -activated carbon nanocomposites as catalysts ... more : Comparative study of dye degradation using TiO 2 -activated carbon nanocomposites as catalysts in photocatalytic, sonocatalytic, and photosonocatalytic reactor, Desalination and Water Treatment,
Culturable methanotrophic bacteria (CMB) were studied in the soils of forest and savanna of tropi... more Culturable methanotrophic bacteria (CMB) were studied in the soils of forest and savanna of tropical dry deciduous forest ecosystems employing most probable number (MPN) technique. The spatiotemporal study was conducted at the six sites differing in the soil physicochemical properties and vegetational cover. CMB population was high in the moist sites compared to the dry sites and in sub soil below 10 cm depth. The top soil population ranged between 7.0 × 10 4 to 7.1 × 10 6 g -1 dry soil. The population declined exponentially with depth. In temporal study at bimonthly interval for two consecutive years, high CMB population was in winter that declined 10 -20 fold in rain. The CMB population variation was explained solely by temperature (59%), temperature and soil nitrate (76%), and temperature soil nitrate and moisture (77.4%) in the step wise regression analysis.
Cellulases have wide applications in the biofuel industry. The three main components, namely endo... more Cellulases have wide applications in the biofuel industry. The three main components, namely endoglucanase, exoglucanase, and -glucosidase effectively convert lignocellulosic biomass into fermentable sugar. The commercial production of cellulase is done using the submerged fermentation; however, it is costly and less economic for biofuels production. Moreover, microbial cellulase production process suffers from various bottlenecks. Because of the low cost, production of cellulase using solid-state fermentation by fungi is preferable. Therefore, the present review provides an overview on cellulase, main aspects of cellulase production and present scenario of cellulase production in the biofuels industry.
Ecoprint: An International Journal of Ecology, 2009
In the present paper 10 Cyanophycean algae belonging 10 genera have been described from eastern U... more In the present paper 10 Cyanophycean algae belonging 10 genera have been described from eastern U.P. The genera described are: Chroococcus, Microcystis, Aphanothece, Arthrospira, Spirulina, Lyngbya, Anabaena, Rivularia, and Gloeotrichia. All these forms are being reported for the first time from eastern U.P., India.doi: 10.3126/eco.v13i0.1627Key words: Cyanophycean algaeEcoprint (An International Journal of Ecology) Vol. 13, No. 1, 2006 Page: 35-39
The present work describes the statistical process optimization of a lowcost production process o... more The present work describes the statistical process optimization of a lowcost production process of PLA using organometallic (stannous octoate) compounds. The process optimization for both lactide and polylactide, was developed by factorial design and response surface methodology. The influence of different experimental parameters such as reaction temperature, time, concentration of catalyst and co-initiator concentration on the yield of lactide and polylactide has been evaluated. There are many studies reported on the synthesis of polylactide but no earlier study exists for the application of statistical analysis in determining the interactions among the process variables for lactide and polylactide production. Central composite experimental design with multiple linear regression has been used to estimate the coefficients of the polynomial model equation for the yield(s) of both lactide and polylactide. The statistical significance of polynomial model equation was validated by F test (ANOVA). Determination coefficient (R 2 ) values found to be 0.913 and 0.958 for lactide and polylactide respectively, states that predicted values were in good agreement with the experimental values. Results of the statistical analysis showed that the model fits in all cases. Above synthesised polymer was characterized by FT-IR, 1 H-NMR, DSC and GPC to confirm the polymer structure and properties.
The synthesis and characterization of Th-MCM-41 and U-MCM-41 new members of a growing family of h... more The synthesis and characterization of Th-MCM-41 and U-MCM-41 new members of a growing family of hexagonal packed metallo-silicates molecular sieves are described. The synthesis of these materials was achieved by a “liquid ...
In this study, chitosan/polylactide (CP) blend solutions in trifluoroacetic acid as a co-solvent ... more In this study, chitosan/polylactide (CP) blend solutions in trifluoroacetic acid as a co-solvent with different blend ratio were electrospun. Effects of different CP ratio and process parameters on the diameter of electrospun nanofibers were experimentally investigated. The fiber morphology and the distribution of fiber diameter were investigated by scanning electron microscopy. Response surface methodology (RSM) was used to define and evaluate a quantitative relationship between electrospinning parameters, average fiber diameters and its distribution for each chitosan-polylactide ratio. Applied voltage and polymer solution extrusion rate are the process variables which control the fiber diameter at similar spinning distances (15 cm). Fiber diameter was correlated to these variables by using a second-order polynomial function. The fibers were of diameter ranging from 94 to 389 nm. The predicted fiber diameters were in good agreement with the experimental results. Contour plots were obtained to identify the processing variables suitable for producing nanofibers. It was concluded that ratio of polylactide and chitosan in the blend polymer played an important role to the diameter of fibers and standard deviation of fiber diameter. The processing factors were found statistically significant in the production of nanofibers.
Performance of ultrasound assisted extraction (UAE) technique for the extraction of colourant fro... more Performance of ultrasound assisted extraction (UAE) technique for the extraction of colourant from Dahlia variabilis has been compared with conventional solvent extraction method. It is observed that UAE is more efficient process as compared to solvent extraction. The extracted dye is also characterized by FTIR and UV spectrophotometer. Change in colour with pH of extracted dye is observed due to bathochromic shift from blue green (pH 8.9) to deep red (pH 2.0). The extracted dye is also used for dyeing of wool yarns, generally used in the carpet industries. Good fastness properties of dyed yarn confirm its utility in the textile industries for eco-dyeing. The extracted dye also shows good potential to replace phenolphthalein as an indicator.
Ultrafiltration (UF) membranes were prepared by blending different proportion of polyvinylidene f... more Ultrafiltration (UF) membranes were prepared by blending different proportion of polyvinylidene fluoride (PVDF), sulphonated polyethersulphone (SPES) and nanoparticles of zirconium oxide (ZrO 2 ). The functional groups, surface and cross-sectional morphologies were analysed using Fourier transform infrared, scanning electron microscopy (SEM) and X-ray diffraction, respectively. The presence of particles and pores in the membrane is clearly revealed from the SEM photomicrographs. The effect of different transmembrane pressures is studied to evaluate the performance of membranes. The best value of the permeate flux with a low fouling recovery ratio is obtained at a transmembrane pressure of 0.3 MPa (3 bars). The performance of the membranes having 4 wt% ZrO 2 nanoparticles was studied with and without backwash. The backwashing is capable of restoring the initial flux to about 90%. SPES and ZrO 2 particles were found to play the role of antifouling agent and the hydrophilicity enhancer in the prepared composite membrane.
: Comparative study of dye degradation using TiO 2 -activated carbon nanocomposites as catalysts ... more : Comparative study of dye degradation using TiO 2 -activated carbon nanocomposites as catalysts in photocatalytic, sonocatalytic, and photosonocatalytic reactor, Desalination and Water Treatment,
Culturable methanotrophic bacteria (CMB) were studied in the soils of forest and savanna of tropi... more Culturable methanotrophic bacteria (CMB) were studied in the soils of forest and savanna of tropical dry deciduous forest ecosystems employing most probable number (MPN) technique. The spatiotemporal study was conducted at the six sites differing in the soil physicochemical properties and vegetational cover. CMB population was high in the moist sites compared to the dry sites and in sub soil below 10 cm depth. The top soil population ranged between 7.0 × 10 4 to 7.1 × 10 6 g -1 dry soil. The population declined exponentially with depth. In temporal study at bimonthly interval for two consecutive years, high CMB population was in winter that declined 10 -20 fold in rain. The CMB population variation was explained solely by temperature (59%), temperature and soil nitrate (76%), and temperature soil nitrate and moisture (77.4%) in the step wise regression analysis.
Cellulases have wide applications in the biofuel industry. The three main components, namely endo... more Cellulases have wide applications in the biofuel industry. The three main components, namely endoglucanase, exoglucanase, and -glucosidase effectively convert lignocellulosic biomass into fermentable sugar. The commercial production of cellulase is done using the submerged fermentation; however, it is costly and less economic for biofuels production. Moreover, microbial cellulase production process suffers from various bottlenecks. Because of the low cost, production of cellulase using solid-state fermentation by fungi is preferable. Therefore, the present review provides an overview on cellulase, main aspects of cellulase production and present scenario of cellulase production in the biofuels industry.
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Papers by Dr. P K Mishra