WorldCat Identities

Thapa, Rajesh 1972-

Works: 9 works in 27 publications in 2 languages and 458 library holdings
Genres: Geographic information systems  Maps  World atlases  Handbooks and manuals 
Roles: Author, Editor, Other
Publication Timeline
Most widely held works by Rajesh Thapa
Spatial analysis and modeling in geographical transformation process : GIS-based applications by Yūji Murayama( )

17 editions published in 2011 in English and German and held by 426 WorldCat member libraries worldwide

Currently, spatial analysis is becoming more important than ever because enormous volumes of spatial data are available from different sources, such as GPS, Remote Sensing, and others. This book deals with spatial analysis and modelling. It provides a comprehensive discussion of spatial analysis, methods, and approaches related to human settlements and associated environment. Key contributions with empirical case studies from Iran, Philippines, Vietnam, Thailand, Nepal, and Japan that apply spatial analysis including autocorrelation, fuzzy, voronoi, cellular automata, analytic hierarchy process, artificial neural network, spatial metrics, spatial statistics, regression, and remote sensing mapping techniques are compiled comprehensively. The core value of this book is a wide variety of results with state of the art discussion including empirical case studies. It provides a milestone reference to students, researchers, planners, and other practitioners dealing the spatial problems on urban and regional issues
New Ekta school atlas( )

2 editions published between 2001 and 2002 in English and held by 15 WorldCat member libraries worldwide

Flash flood risk management : a training of trainers manual by Arun Bhakta Shrestha( Book )

2 editions published in 2011 in English and held by 10 WorldCat member libraries worldwide

This manual was designed to help build the capacity of trainers in the field of flash flood risk management it is largely based on ICIMOD's Resource Manual on Flash Risk Management, Module 1 (Shrestha et al. 2008) Module 2 (Shrestha 2008). The manual was fested during the Integrated Approach to Flash Floods and Flood Risk Management in the Hindu Kush-Himalayan Region Training of Trainers Workship which was organised by ICIMOD from 25 Octiber to 2 November 2010 in Kathmandu, and revisions were incorporated
Land assessment framework for peri-urban agriculture : an integrated approach of geospatial and analytic hierarchy process techniques : case study of Hanoi Province, Vietnam by Rajesh Thapa( Book )

1 edition published in 2010 in English and held by 2 WorldCat member libraries worldwide

In order to gain higher productivity and profitability, the competition between demand and supply of land for different activities plays crucial role in land use morphology that challenges urban and peri-urban land use planners and managers. The transformation of conventional More ... agricultural areas to modern cash crops and urban areas is a current trend in peri-urban Hanoi. The land assessment framework for sustainable peri-urban agriculture was a result of the combined techniques of Remote Sensing (RS), Geographic Information System (GIS), and Analytical Hierarchical Process (AHP) integrated with local knowledge. The whole framework identifies the urban sprawl dynamics and directions over the last decade, the land use patterns, and the linkages between peri-urban and urban areas, and it prepares a spatial decision scenario for the peri-urban agriculture at different levels of suitability. This empirical framework provides a cost effective, rapid land evaluation framework which can be easily propagated to other areas and may help policy makers, urban and regional planners, and researchers working in developing countries
Ekta school atlas( )

1 edition published in 2006 in English and held by 1 WorldCat member library worldwide

Phosphinimine zinc complexes and neutral phosphinimines for ring opening polymerization of lactides by Rajesh Thapa( )

1 edition published in 2015 in English and held by 1 WorldCat member library worldwide

Achiral arenesulfonates ligands having a (NNN) or (NNO) side arm have been developed (Chapter 2) and their respective zinc ethyl complexes, NNNZnEt 3.2 and NNOZnEt 3.3, have been synthesized and characterized using spectroscopic methods (Chapter 3). NNNZnEt as well as NNOZnEt complexes are stable under nitrogen atmosphere. In the NNOZnEt 3.3 complex the protons associated with the pendant (dimethylamino)ethyl arm are broad indicating that a fluxional process is operative, most likely dissociation of the (dimethylamino)ethyl arm at 25 °C in CD2Cl2. The fluxional behavior present in the 1H NMR spectrum of 3.2 could be arrested by cooling the CD2Cl2 solution to -60 °C. In Chapter 3, the reactivity of 3.2 and 3.3 with alcohols was explored in detail. NNOZnEt was found to be unstable in the presence of alcohols. The NNNZnEt complex does not show any reactivity with weak acids (pKa = 16), such as ethanol, anthrylmethanol or anthrylethanol. Strong acids (pKa = 8-10) like phenols protonate the zinc ethyl bond to produce zinc phenoxide complexes with release of ethane. The rate of the reaction is directly proportional to the acid strength (pKa) of the alcohols. The NNNZnEt complex as well as its corresponding phenoxides show dynamic behavior at 25 °C. The dimethylaminoethyl arms in these complexes are hemilable as indicated by 1H, 13C, 31P and variable temperature NMR, i.e., the dynamic behavior of these complexes was demonstrated. The detail structure of the NNNZnEt was elucidated by examining the single X-crystal structure of analogous air stable NNNZnMe complex. Zinc phenoxides 3.10-3.12 were isolated in good yield by reaction of NNNZnEt complex and one equivalent of the corresponding solid phenols in CH2Cl2 under N2. Zinc phenoxides 3.10- 3.12 were characterized by 1H, 13C, and 31P and multi-dimensional NMR. Fluxional behavior was observed at 25 °C for the pendant (dimethylamino)ethyl arm in complexes 3.10-3.12 as also seen in zinc alkyl complexes 3.7 and 3.13. The dynamic behavior due to association and disassociation of the (dimethylamino) ethyl arm in complexes 3.10- 3.12 could be halted by cooling the CD2Cl2 solutions to -40 °C. Complexes 3.10-3.12 were stable in dry CD2Cl2 for several days at 25 °C and 12 hours at 45 °C. The catalytic activity of zinc phenols with lactide were tested on NMR scale reactions. The discrete zinc phenoxide as well as in situ generated zinc phenoxides 3.10-3.12 show low catalytic activity with dl-lactide. The low reactivity of zinc phenoxides with dl-lactide is probably due to the low electrophilicity of the zinc center. In the second part of this dissertation (Chapter 4), a series of tolyl/phenylethyl phosphinimines 4.1-4.8 were synthesized by Staudinger reaction between azide and various phosphines. These phosphinimines were characterized using 1H, 13C, 31P NMR. In general, the phosphininimine only ring substituted with an electron donating group, such as methoxy or dimethylanino, enhances the basicity of the phosphinimines. The correlation between the basicity of the phosphinimines and the downfield shift of the alcohol hydroxyl group when activated by phosphinimine was studied. The catalytic activity of these phosphinimines towards ring opening polymerization of lactide is correlated by alcohol hydroxyl proton shift when interacted with an alcohol (1:1) in nonhydrogen bonding solvent CDCl3 at 25 °C under N2 atmosphere. The phosphinimines 4.5 to 4.14 were tested for ROP of lactides and their correlation with the basicity estimated with alcohol activation was shown. These phosphinimines represent highly active catalysts for ROP under N2 at ambient temperature. The phosphinimine 4.7 reacts with lactide monomer even in absence of alcohol initiation with reasonable reaction rate. Phosphinimines initiate the ROP of lactide even in the absence of initiating alcohol. However, the addition of alcohol enhances the rate of the reaction. We anticipate that the ease of handling of these catalysts, combined with their high reactivity on the ROP of lactide will make them useful to the synthetic community
Regioselectivity in free radical bromination of unsymmetrical dimethylated pyridines by Rajesh Thapa( )

1 edition published in 2009 in English and held by 1 WorldCat member library worldwide

During a literature review some curious inconsistencies in the free radical bromination of picolines were noted. To achieve a better understanding of the mechanisms and regioselectivity we reran these reactions, extending our work to unsymmetrical lutidines using N-bromosuccinimide in limiting amount. Characterization of the products was done with GC/MS and H NMR. The regioselectivity of bromination in unsymmetrical dimethylpyridines shows that nitrogen in the ring is deactivating inductively. The competition between 2,3, 2,4 and 2,5 dimethyl pyridine towards bromination results with bromination in the methyl group farthest from the N in the ring. 3,4-Lutidine shows only the 4,4- dibrominated product
Cr:forsterite laser frequency comb stabil[a]zation and development of portable frequency references inside a hollow optical fiber by Rajesh Thapa( )

1 edition published in 2008 in English and held by 1 WorldCat member library worldwide

We have made significant accomplishments in the development of portable frequency standard inside hollow optical fibers. Such standards will improve portable optical frequency references available to the telecommunications industry. Our approach relies on the development of a stabilized Cr:forsterite laser to generate the frequency comb in the near-IR region. This laser is self referenced and locked to a CW laser which in turn is stabilized to a sub-Doppler feature of a molecular transition. The molecular transition is realized using a hollow core fiber filled with acetylene gas. We finally measured the absolute frequency of these molecular transitions to characterize the references. In this thesis, the major ideas, techniques and experimental results for the development and absolute frequency measurement of the portable frequency references are presented. A prism-based Cr:forsterite frequency comb is stabilized. We have effectively used the prism modulation along with power modulation inside the cavity in order to actively stabilize the frequency comb. We have also studied the carrier-envelope-offset frequency (f0) dynamics of the laser and its effect on laser stabilization. A reduction of f0 linewidth from [similar to]2 MHz to [similar to]20 kHz has also been observed. Both our in-loop and out-of-loop measurements of the comb stability showed that the comb is stable within a part in 10^11 at 1-s gate time and is currently limited by our reference signal. In order to develop this portable frequency standard, saturated absorption spectroscopy is performed on the acetylene v1+v3 band near 1532 nm inside different kinds of hollow optical fibers. The observed linewidths are a factor 2 narrower in the 20 um fiber as compared to 10 um fiber, and vary from 20-40 MHz depending on pressure and power. The 70 um kagome fiber shows a further reduction in linewidth to less than 10 MHz. In order to seal the gas inside the hollow optical fiber, we have also developed a technique of splicing the hollow fiber to solid fiber in a standard commercial arc splicer, rather than the more expensive filament splicer, and achieved comparable splice loss. We locked a CW laser to the saturated absorption feature using a Frequency Modulation technique and then compared to an optical frequency comb. The stabilized frequency comb, providing a dense grid of reference frequencies in near-infrared region is used to characterize and measure the absolute frequency reference based on these hollow optical fibers
Doppler-free spectroscopy of acetylene in near infrared spectral region inside photonic band gap fiber by Rajesh Thapa( )

1 edition published in 2005 in English and held by 1 WorldCat member library worldwide

We investigate the nonlinear spectroscopy of acetylene in the near infrared region inside a photonic band gap fiber. The near infrared region of the optical spectrum is an area of intensive research due to its relevance to telecommunication and optical metrology. Acetylene provides a large number of reference transitions coincident with the international telecommunication band. Acetylene contains about 50 strong lines between 1510 nm and 1540 nm in the [nu symbol subscript1]+[nu symbol subscript3] ro-vibrational combination band. We have observed the Doppler-free saturated spectrum of several of these lines. The light from a tunable diode laser at ~1531 nm, resonant with the P(11) transition, is amplified by an erbium doped fiber amplifier and split into a strong pump beam and weak probe beam which counter-propagate inside the gas-filled fiber. The measured Doppler linewidth of the P(11) line at room temperature is about 467 MHz wide. The sub-Doppler profile over a pressure range of 200-1600 mT appears as a narrow absorption feature about 20-40 MHz wide, even at the low pump power of ~10 mW. It is found that for a fiber with an 80 cm length, 20 core size, pumped with 29 mw, the optimum pressure is ~530mT. But the optimum pressure condition will further decrease when the fiber length increases
Audience Level
Audience Level
  Kids General Special  
Audience level: 0.49 (from 0.09 for Ekta schoo ... to 0.80 for Flash floo ...)

Spatial analysis and modeling in geographical transformation process : GIS-based applications
Alternative Names
Rajesh Thapa 1972-

Thapa, R. 1972-

English (26)

German (1)