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Soft Nanoscience Letters 2015年第1期5卷 3-11页

作者： pratima parashar pandey Department of Materials Science Mangalore University Mangalagangotri India

Silver particulate thin films on softened polymer blends of Polystyrene (PS)/Poly(2-vinyl pyridine) (P2VP), PS/Poly(4-vinylpyridine) (P4VP), and Poly(vinylpyrollidone) (PVP)/P4VP at a rate of 0.4 nm/s held at a temperature of 457 K in vacuum of 8 × 10-6 Torr by evaporation are deposited. These silver films were characterized by their electrical behavior, optical properties and Scanning electron microscopy (SEM). Silver films deposited on softened PS, and PVP give rise to a very high room temperature resistance approaching that of the substrate resistance due to the formation of a highly agglomerated structure. On the other hand, silver films on softened P2VP and P4VP give rise to a room temperature resistance in the range of tens to a few hundred MΩ/ which is desirable for device applications. Silver films on the composites of PS/P2VP, PS/P4VP and PVP/P4VP show resistances at room temperature. The optical and plasmonic response of Ag nanoparticles onto thin layers of blends shows encapsulation of nanoparticles. The electrical properties and SEM of silver nanoparticles on the thin layers of polymer blends indicate the formation of much smaller, narrower dispersion and wide size distribution.

关键词： Nanoparticles Polymer Blends Thin Films Vapor Deposition Electrical Properties Optical Properties SEM

Preparation and Characterization of Polymer Nanocomposites

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Soft Nanoscience Letters 2020年第1期10卷 1-15页

作者： pratima parashar pandey Applied Sciences CET IILM Greater Noida India

The polymer nanocomposites have been the exponentially growing field of research for developing the materials in last few decades. The remarkable improvement in the polymer nanocomposite is found when a small amount of nanosized particles are added to a polymer matrix. The addition of inorganic solid nanoparticles (typically in the form of fibres, flakes, spheres or fine particles) into polymer matrix increases their physical, structural and mechanical properties. Since the polymer-nano composites have been the staple of modern polymer industry, their durability under various environmental conditions and degradability after their service life are also essential fields of research. This leads to focus on preparation & characterization of polymer nanocomposite. This article is intended to review the status of worldwide research in this aspect. The successful application of nano particles depends upon both the correct preparation techniques followed by testing through characterization. Surface modification can improve the inherent characteristics of the nano particles and serve to prepare nano composites inexistent in nature. Therefore, some tools as their various properties like electrical, optical and morphological can be used to optimize the preparation of polymer nano composites. This chapter will make an overview about different routes to prepare polymer-based nano composites by extrusion, synthesis of nano particles by sol-gel reactions, sputtering and mainly by physical evaporation deposition method.

关键词： Silver Nano-Particle Polymer Composite Electrical Properties Optical Properties DSC FTIR SEM Morphology

Glacier-Glacial Lake Interactions and Glacial Lake Development in the Central Himalaya,India(1994–2017)

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Journal of Earth Science 2021年第6期32卷 1563-1574页

作者： pratima pandey Sheikh Nawaz Ali Prashant Kumar Champati Ray Indian Institute of Remote Sensing DehradunIndia Birbal Sahni Institute of Palaeosciences LucknowIndia

Despite several regional glacier and glacier lake inventories, the relationship between receding glacier, glacial lake evolution(glacial-lake interactions) and their sensitivity to different forcing factors have not been properly understood yet. To better understand these processes, we used satellite images collected in 1994, 2015 and 2017 to monitor the spatially-explicit evolution of glacial lakes and glacier changes. The results show a total of 1 353 glacial lakes covering an area of 7.96 km;in the year 2015. Out of these, a total of 137 glacial lakes having an area of >0.01 km;and located within 2 km periphery of mother glacier have been selected for the monitoring of spatial development between 1994 and 2017. We found an increase in the total lake area from ~4.9 to ~7.73 km;between 1994 and 2017,corresponding to an overall expansion of ~57%. The total area covered by the glaciers associated with these lakes reduced from ~365 km;in 1994 to ~358 km^(2) in 2017, accounting for a glacier loss of ~7 km^(2) and corresponding to ~1.92% reduction. Our study results are in agreement with global glacier behavior, revealing a rapid glacier recession and accelerated glacial lake expansion under an unprecedented climate change scenario. In addition, the results suggest a significant reduction in the glacier area and a close relationship between the glacier melting and lake changes.

关键词： glacial lake expansion glacier change glacier-lake interaction Central Himalaya climate

Regional representation of glaciers in Chandra Basin region,western Himalaya,India

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Geoscience Frontiers 2017年第4期8卷 841-850页

作者： pratima pandey S.Nawaz Ali AL.Ramanathan P.K.Champati ray G.Venkataraman Geosciences and Geohazards Department Indian Institute of Remote Sensing Birbal Sahni Institute of Paleosciences School of Environmental Science Jawaharlal Nehru University Centre of Studies in Resource Engineering Indian Institute of Technology

Hamtah and Chhota Shigri are two nearby,well monitored glaciers of western Himalaya,lying in the same climatic zone and driven by the same climatic *** this study,topographical characteristics of both the glacier have been explored to understand the role of topography in controlling the glacier ***,their topographical characteristics and possible response towards climatic variations have been compared with each other and also with that of the other glaciers in the basin to find out the suitability of these two glaciers to be considered as representative of the *** sensor and multi temporal remote sensing data have been used to carry out to fulfill the *** is found that being in the same climatic zone,the mean accumulation area ratio of Chhota Shigri is 54%and Hamtah is 11%between 1980 and *** comparison to Hamtah,Chhota Shigri glacier has a small upslope area,low compactness ratio indicating the ability of the glacier to receive direct precipitation and solar *** analysis revealed that the Chhota Shigri glacier has a closer resemblance with the other glaciers in the region than Hamtah ***,the topographical settings of Chhota Shigri glacier are suitable for recording and reflecting year-to-year climatic variations.

关键词： Himalaya Glacier Regional representation Topography Remote sensing

Decision-making by nematodes in complex microfluidic mazes

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Advances in Bioscience and Biotechnology 2011年第6期2卷 409-415页

作者： Santosh pandey Andrew Joseph Roy Lycke Archana parashar 不详

Nematodes are microscopic, soil-dwelling worms that navigate through soil particles in search of food or a suitable host. Most nematode species employ a myriad of physical and chemical cues that define their navigation strategies. Here, we demonstrate a microfluidic method to observe and characterize the physical aspects of nematode navigation at real-time. The microfluidic devices comprise a series of interconnected T-maze or cylindrical structures of varying geometry. At each physical intersection, nematodes are given the choice to migrate left or right. We found that this decision-making of nematodes is influenced by the angle of intersection of T-maze structures. We further showed that nematodes can be passively directed to move in a linear direction by carefully adjusting the position and spacing of cylindrical obstacles in its path. The experiments were conducted on two nematodes (non-parasitic C. elegans and pigparasitic Oesophagostomum dentatum) and in the absence of any chemical or electrical stimulants.

关键词： C. elegans Navigation Maze Microorganism Microfluidics

Removal of Chromium(III) from the Waste Solution of an Indian Tannery by Amberlite IR 120 Resin

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International Journal of Nonferrous Metallurgy 2012年第3期1卷 32-41页

作者： pratima Meshram Sushanta Kumar Sahu Banshi Dhar pandey Vinay Kumar Tilak Raj Mankhand Department of Metallurgical Engineering IIT BHU Varanasi India Metal Extraction & Forming Division CSIR-National Metallurgical Laboratory Jamshedpur India

The extraction of chromium(III) from a model waste solution and also from a waste solution of an Indian tannery with Amberlite IR 120 resin is described, and the performance of this resin is compared with other similar resins. The parameters that were optimized include effect of mixing time, pH, loading and elution behaviours of chromium(III) for this resin. Sorption of chromium(III) on Amberlite IR 120 followed Freundlich isotherm and Langmuir isotherm model, and the maximum sorption capacity was determined to be 142.86 mg Cr(III)/g of the resin. Higher Freundlich constant (Kf) values (6.30 and 13.46 for aqueous feed of 500 and 1000 ppm Cr(III)) indicated strong chemical interaction through ion exchange mechanism of the metal ion with the resin. The kinetic data showed good fit to the Lagergren first order model for extraction of chromium(III). Desorption of chromium(III) from the loaded resin increased with the increase in concentration of eluent (5-20% H2SO4). With 20% (v/v) sulphuric acid solution 94% chromium(III) was eluted in three stages. Elution of the Cr(III) in the column experiments was however, found to be lower (82%) than that of the shake flask data. In case of Indian tannery’s waste solution, it was observed that almost total chromium was extracted in four stages with Amberlite IR 120.

关键词： Chromium(III) Ion exchange Amberlite IR 120 Tannery Waste Solution

Crucial, But not Systematically Investigated: Rock Glaciers, the Concealed Water Reservoirs of the Himalayas: An Opinion

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Journal of Atmospheric Science Research 2023年第2期6卷 33-41页

作者： Sheikh Nawaz Ali pratima pandey Birbal Sahni institute of Palaeosciences Lucknow226007India Indian Institute of Remote Sensing Dehradun248001India

The current article is an opinion on the sensitivity of high mountain regions which are the most fragile,sensitive and vulnerable to ongoing climate *** impacts are especially severe on the high mountain communities owing to their weak socio-economic profile,limited livelihood resources and agricultural *** melting of glaciers and changes in the snow cover under the climate change scenario is leading to the scarcity of freshwater supplies,affecting both local and downstream *** in the precipitation patterns have been suggested to cause droughts,impact restricted agriculture,and limit the availability of water for domestic ***,the high mountain areas contain distinct flora and fauna,and climate change is not just altering them,but also has resulted in biodiversity loss as species are unable to adapt to the changing *** of its higher altitudes and semi-arid to arid climate,the consequences of climate change are more evident in the higher *** change is affecting the availability of key resources,such as freshwater and agriculture and pasture lands,resulting in food and water insecurity and their reliance on imports from other *** a result,high mountain communities in the Himalayas are progressively shifting to higher glacier valleys in search of suitable cultivable land with adequate *** are engaging in agro-pastoral activities around thermokarst lakes(Oasis)atop rock glaciers as part of this *** actions underscore the crucial role of rock glaciers in dealing with and adjusting to the consequences of climate *** its relevance,rock glacier research in the Himalayan region is still in its *** purpose of this work is to emphasise the significance of these major climate-resilient water resources,as well as the methodology that must be adopted for their systematic and compressive investigations.

关键词： Climate change Rock glaciers Evolving agricultural practices Systematic study Higher Himalayas