Microrheological Studies of Regenerated Silk Fibroin Solution by Video Microscopy

We have carried out studies on the rheological properties of regenerated silk fibroin (RSF) solution using video microscopy. The degummed silk from the Bombyx mori silkworm was used to prepare RSF solution by dissolving it in calcium nitrate tetrahydrate-methanol solvent. Measurements were carried out by tracking the position of an embedded micron-sized polystyrene bead within the RSF solution through video imaging. The time dependent mean squared displacement (MSD) of the bead in solution and hence, the complex shear modulus of this solution was calculated from the bead's position information. An optical tweezer was used to transport and locate the bead at any desired site within the micro-volume of the sample, to facilitate the subsequent free-bead video analysis. We present here the results of rheological measurements of the silk polymer network in solution over a frequency range, whose upper limit is the frame capture rate of our camera, at full resolution. By examining the distribution of MSD of beads at different locations within the sample volume, we demonstrate that this probe technique enables us to detect local inhomogeneties at micrometer length scales, not detectable either by a rheometer or from diffusing wave spectroscopy.Comment: 5 page

Future Prediction of Land Covers in Devikulam Taluk, Kerala

Land Cover of the Earth is undergoing significant transformation due to natural and human induced interventions. Information about land use change is very essential for planning, monitoring and management of natural resources. Prediction of natural and social causes of land cover change through spatially explicit models is made possible by GIS and other computer based techniques which can define and test relationships between environment and social variables using a combination of existing data, observations on the ground and the data from remote sensing. This study is proposed with an objective to inventory various land cover classes in Devikulam Taluk, Kerala. With the help of temporal data sets, the dynamics of the different land use classes in the study area has also been attempted. An attempt is made to correlate each land cover class for the Land Transformation Model (LTM) developed based upon Markov and Cellular Automata. Using the developed LTM, generation of the future scenario of land cover of the study area has been attempted. This information is expected to be useful for the assessment of land cover change and plan for better land management strategies after a review of the future trends in the land cover patterns. This study shows the extent of forest area which is degraded and converted to other land cover classes

Land Cover Dynamics of Devikulam Taluk-Understanding the Past Scenario

Monitoring land cover change is the most important step in decision making for local or government agencies. Specially for a forest recovery program, understanding of the past scenario of land cover is very essential. It is also very important to understand the past scenario of the land cover for identification of areas for afforestation programs in the country. In this study we have tried to understand the land cover trend before the start of 21st century. IRS LISS-I image of 1989 is the oldest high resolution imagery available, therefore land cover change from 1989. IRS LISS-II imageries for 1993 and 1997 were used by taking into account four year time interval. The imageries were digitally classified and compared to obtain the land cover change statistics. The exact areas were also identified by overlaying the classified imageries. It is observed that an area of about 23790 Ha out of 78721 Ha dense forest in the year 1989 was converted to other land cover category by 1997, which means about 27% of dense forest area was reduced to 19% by 1997. An increase in the built up class was also observed from 1000 Ha in 1989 to about 2074 Ha in 1997. This study has established that a major portion of the forested land were already degraded even before stringent forest Act came into existence. The land cover change pattern also helps in predicting the future land cover trends

Monitoring of Pesticide Residues in Farmgate Samples of Vegetables in Karnataka, India

Fifty Vegetable samples in Ramanagara district of Karnataka, India were analysed for 20 pesticide residues. Vegetable samples were extracted with acetonitrle and the pesticides are partitioned into petroleum ether and evaluated by gas liquid chromatography equipped with ECD and FTD. Recovery studies were performed at 0.1, 0.5 and 1.0 mg kg -1 fortification levels of each compound and the recoveries obtained ranged from 80.5% to 96.2% with relative standard deviations lower than 7%. The method showed good linearity over the range assessed 0.05-1.5mg kg -1 with correlation coefficient> 0.998 and the detection and quantification limits for the pesticides studied varied from 0.0001 to 0.044 mg kg -1 and 0.0005 to 0.0155 mg kg -1 , respectively. All the samples were found to be contaminated; the organo chlorines (83.5%) dominated followed by organophosphates (67%) and pyrethroids (55%). However, 34% of the samples were found to contain the residues of organophosphate insecticides above their respective maximum residue limits (MRL). It is therefore proposed to perform extensive monitoring studies covering all the vegetable crops from different agro-climatic regions of the state to know the exact status of pesticide contamination

Electro‐optic effects in nematic liquid crystals

Experimental results on the electro-optic effects in nematic liquid crystals are presented. A hexagonal grid pattern is observed with (ac + dc) field at a critical frequency f(c) (168 Hz). The time required for the formation of the grid pattern with applied field is estimated

Biological assessment of water pollution: A study of the river Kapila

An attempt has been made to assess the feasibility of application of biological data to evaluate and monitor water pollution of the river Kapila, near Nanjangud, Karnataka. Two pollution index factors, one at the generic level and another at species level of the Algae, have been computed. Significant correlation between biological and some physico-chemical factors has been established. The theme that algae serve as tools of pollution and that their index scores at the species level is a more reliable parameter for the evaluation of water quality has been established. © 1984, Taylor & Francis Group, LLC. All rights reserved

Characterization of Zinc Nanoferrite Doped HPMC Polymers Using X-Ray Diffraction

HPMC Polymer composites were prepared by doping various concentrations of Zinc ferrite nanoparticles using solution casting method. These polymer composites were characterized using X-Ray Diffraction and conductivity measurements. The addition of nanoferrites in the polymer matrix do change the structural and the AC conductivity properties of the film, which is supported by the results obtained and they are discussed briefly in this paper