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Tripathi R.,Government Post Graduate College | Kumar A.,Government Post Graduate College | Bharti C.,Tilka Manjhi Bhagalpur University | Sinha T.P.,Bose Institute of India
Current Applied Physics | Year: 2010

Thioglycerol capped nanoparticles of ZnO have been prepared in methanol through chemical technique. Nanostructures of the prepared ZnO particles have been confirmed through X-ray diffraction measurement. The Debye-Scherrer formula is used to obtain the particle size. The average size of the prepared ZnO nanoparticles is found to be 50 nm. The frequency-dependent dielectric dispersion of the sample is investigated in the temperature range from 293 to 383 K and in a frequency range from 100 Hz to 1 MHz by impedance spectroscopy. An analysis of the complex permittivity (ε′ and ε′′) and loss tangent (tan δ) with frequency is performed assuming a distribution of relaxation times. The frequency-dependent maxima of the imaginary part of impedance are found to obey Arrhenius law with activation energy ∼1 eV. The scaling behavior of dielectric loss spectra suggests that the relaxation describes the same mechanism at various temperatures. The frequency-dependent electrical data are analyzed in the framework of conductivity and modulus formalisms. The frequency-dependent conductivity spectra obey the power law. © 2009 Elsevier B.V. All rights reserved.


Tiwari P.C.,Kumaun University | Joshi B.,Government Post Graduate College
Water Resources Management | Year: 2012

The nature of terrain imposes severe limitations on the scale of productive activities as well as on the efficiency of infrastructural facilities in the Indian Himalaya. As a result, biomass based subsistence agriculture constitutes the main source of rural livelihood. During the recent past, rural resource development practices have changed in response to population increase and the resultant increased demand on natural resources as well as increasing socio-economic and political marginalization. This has brought about rapid environmental changes which have reduced the groundwater recharge in the region. About 36% of springs have dried, heads of perennial streams have dried and water discharge in springs and streams has decreased considerably resulting into severe crisis of water for drinking as well as irrigation during the past 20 years. In addition to assessing the impact of recent environmental changes on water resources, this paper attempts to develop a community and user oriented framework for the sustainable development of water resources with a case illustration of Kosi headwater in Kumaon Lesser Himalaya, India. © 2011 Springer Science+Business Media B.V.


Tiwari P.C.,Kumaun University | Joshi B.,Government Post Graduate College
Landslide Science and Practice: Global Environmental Change | Year: 2013

In Himalaya, increasing rainfall variability has accelerated landslide activity damaging cultivated land and devastating agricultural infrastructure. Paper aims to analyze rainfall variability and interpret its linkages with landslides and food security with an example of Kumaon Himalaya. Food security in the region depends on local agricultural production, food purchasing power, and road connectivity. Study revealed that both number of rainy days as well as amount of rainfall reduced respectively by 18 % and 25 % during last 10 years, but incidences of high intensity rainfall, cloud bursts and flash floods have increased. This has triggered landside activity devastating 4.83 ha cultivated land, 800 m canals length and 3,891 m road network ever year. Consequently, food production has declined by 15 % rendering 45 % families highly vulnerable to food insecurity. Adaptive agricultural land use planning and diversification and improvement of rural livelihood could reduce vulnerability of mountain communities to climate change and food insecurity. © Springer-Verlag Berlin Heidelberg 2013.


Singh H.,Government Post Graduate College | Singh H.,Indian Institute of Technology Roorkee | Yadav K.L.,Indian Institute of Technology Roorkee
Journal of the American Ceramic Society | Year: 2014

Spinel-perovskite magnetoelectric (ME) nanocomposites xMgFe2O4-(1-x)BiFeO3, x = 0.1, 0.2, 0.3, and 0.4 were synthesized by sol-gel method and characterized by differential thermal analysis, X-ray diffraction analysis, dielectric and magnetic measurements. The samples were calcined at various temperatures and then the effect of annealing temperature on structural and magnetic properties was studied. From transmission electron microscopy, the average crystal size was found to be 30-50 nm. The magnetic behavior is found to be dependent on annealing temperature and magnesium ferrite content. The dielectric behavior with frequency and temperature has been modified with the induction of magnesium ferrite. The relative change of dielectric constant with magnetic field was observed in the nanocomposites. This relative change of magnetic field-induced dielectric constant can also be expressed by Δε∼ γM2 (where γ is magnetoelectric coupling coefficient). © 2014 The American Ceramic Society.


Gupta R.K.,Government Post Graduate College | Sharma C.,Government Post Graduate College
African Journal of Biotechnology | Year: 2010

Many microorganisms form symbioses with plants that range on a continuous scale, from parasitic to mutualistic. Among these, the most widespread mutualistic symbionts is the arbuscular mycorrhiza, formed between arbuscular mycorrhizal (AM) fungi and vascular flowering plants and other plants. A study of diversity of arbuscular mycorrhizal fungi in Camellia sinensis was conducted in four plantation territories of Uttarakhand. Microscopic analysis of the mycorrhizal status of roots has revealed that samples from all four locations belonged only to AM fungi. The mycorrhizal colonization level was found high thus reflecting the mycotrophic nature of C. sinensis (L.). Results of isolation and identification of spores from all field-collected soil samples has revealed relatively higher spore count. All recovered spores were found to belong to the Glomales Order, represented by Glomaceae family. Isolation has also brought into notice that three groups were dominant: the first one included light yellow colored spores, second, corresponded dark yellow-brown colored spores and third, magenta colored spores. The morphological characters indicated that the spore populations consisted of 3 - 6 morphotypes. The Glomus genus was represented by three species; that is, Glomus mossae, Glomus fasciculatum, Glomus sp. 1 (an unidentified species). © 2010 Academic Journals.


Chamola A.,Hemwati Nandan Bahuguna Garhwal University | Singh H.,Government Post Graduate College | Naithani U.C.,Hemwati Nandan Bahuguna Garhwal University
Advanced Materials Letters | Year: 2011

(1-x)BaTiO3-xPZT(65/35) ceramics were prepared by high temperature solid state reaction technique. Structural properties of the compounds were examined using an X-ray diffraction (XRD) technique to confirm the formation of phase at room temperature. Detailed studies of dielectric properties of (1-x) BaTiO3-xPZT(65/35) for all compositions were in temperature range 30-200 °C reveal that the compound have transition temperature well above at the room temperature. While pure BaTiO3 ceramics exhibited a sharp phase transformation expected for normal ferroelectrics, phase transformation behavior of the (1-x) BaTiO3-xPZT(65/35) solid solutions became more diffuse with increasing PZT(65/35) contents. The diffusivity of the dielectric peaks in the compound exhibited the values between 1 and 2 where the higher value indicates the greater disorder in the systems. This was primarily evidenced by an increased broadness in the dielectric peak, with a maximum peak width occurring at x = 0.5. The temperature dependence of ac conductivity indicated that the electrical conductivity decrease above TC on increasing the PZT(65/35) contents. This increase in the conductivity is attributed to the increase in polarizability of the materials around Tc, due to oxygen vacancies. © 2011 VBRI press.


Tiwari P.C.,Kumaon University | Joshi B.,Government Post Graduate College
Environmental Science and Policy | Year: 2015

This paper examines the role of local and regional institutions in environmental governance in Hindu Kush Himalaya (HKH). These institutions have been playing a significant role in regional environmental governance, particularly through generating and disseminating critical knowledge, mobilizing resources and addressing marginality, and regional environmental fragility. However, local and regional institutions have not yet comprehensively addressed the issues of poverty, livelihood, food security, gender inequality, education and social marginalization that affect the entire process of environmental governance. Community access to and involvement in critical socio-economic sectors such as infrastructure and health and education systems, including their governance processes, did not improve due to a lack of inter-linkages within and between local and regional institutions. This underlines the need for capacity building and the development of partnerships and horizontal and vertical linkages among local, regional and national institutions. These practical advances would facilitate improved access to new knowledge, technology and critical information and encourage the movement of financial resources to local levels. © 2014 Elsevier Ltd.


Verma K.L.,Government Post Graduate College
Latin American Journal of Solids and Structures | Year: 2014

Analysis for general closed form solution of the thermoelastic waves in anisotropic heat conducting materials is obtained by using the solution technique for the biquadratic equation in the framework of the generalized theory of thermoelasticity. Obtained results are general in nature and can be applied to the materials of higher symmetry classes such as transvesely isotropic, cubic, and isotropic materials. Uncoupled and coupled thermoelasticity are the particular cases of the obtained results. Numerical computations are carried out on a fiber reinforced heat conducting composite plate modeled as a transversely isotropic media. The two dimensional slowness curves corresponding to different thermal relaxations are presented graphically and characteristics displayed are analyzed with thermal relaxations. © 2014, Brazilian Association of Computational Mechanics. All rights reserved.


Negi C.S.,Government Post Graduate College
Mountain Research and Development | Year: 2010

Cultural diversity in remote mountain regions is closely linked to biodiversity, as there is a symbiotic relationship between habitats and cultures, and between ecosystems and cultural identity; indeed, religious rules and rituals often strengthen this relationship and are characterized by a conservation ethic. The present paper presents an analysis of information collected from knowledgeable members of mountain communities in the State of Uttarakhand, Central Himalaya. The data collected are analyzed within the framework of traditional knowledge-based systems (TKBS) methodology, using the conservation purpose of rules and practices as a means of typifying the information on sacred natural sites (forests/groves, pastures, water bodies), on the phenomenon of dedicating forests to a deity, on the inherent taboos regarding resource exploitation, and on other traditional beliefs and customs, in order to understand the environmental and conservationist implications of these rules and practices. The analysis shows that the cultural precepts of remote Uttarakhand mountain communities can be considered a precondition for sustainable development. In fact, the association of religion with ecosystem management is inherent in traditional Himalayan communities' culture; one cannot think of ecological systems in the Himalaya without religion. However, this knowledge and related conservation rules need to be strengthened in the face of current change. © 2010 International Mountain Society.


Negi C.S.,Government Post Graduate College
Indian Journal of Natural Products and Resources | Year: 2014

Morels, also known as sponge mushrooms, belong to the genus Morchella Dill. The present paper deals with the most commonly exploited species of this genus in the Darma valley, district Pithoragarh, Kumaun Himalaya with an aim to improve upon the knowledge base about these macrofungi for further exploration. © 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.

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