676 research outputs found
Crystal structure of 2,4-bis(2-chlorophenyl)-7-tert-pentyl-3-azabicyclo[3.3.1]nonan-9-one
No full textThe title compound, C25H29Cl2NO, which is a chloro analog of 2,4-bis(2-bromophenyl)-7-(tert-pentyl)-3-azabicyclo[3.3.1]nonan-9-one [Park, Ramkumar & Parthiban (2012). Acta Cryst. E68, o2946], exists in a twin-chair conformation with an equatorial orientation of the 2-chlorophenyl groups. The tert-pentyl group on the cyclohexanone adopts an exocyclic equatorial position and is disordered between two orientations in a ratio 0.520 (8):0.480 (8). The crystal packing shows no directional contacts beyond van der Waals contacts
Generalized drift-diffusion for microscopic thermoelectricity
No full textThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 191-193).Although thermoelectric elements increasingly incorporate nano-scale features in similar material systems as other micro-electronic devices, the former are described in the language of irreversible thermodynamics while devices such as heterojunction bipolar transistors and semiconductor lasers are often described with the drift-diffusion equations. We present a microscopic description of the thermoelectric effects using a generalization of the common drift-diffusion formulation of semi-classical transport. We then replicate these basic results in a commerical device simulation package to explore Peltier cooling at a basic p-n junction. This framework should enable the design of spatially-inhomogenenous thermoelectric elements and internally-cooled micro-electronic devices.by Parthiban Santhanam.S.M
A review of zirconium disulfide: Structural characterization, properties, applications, and prospects of dichalcogenide materials
No full textIn recent decades, two-dimensional (2D) materials have attracted significant attention for their unique electronic, optical, mechanical, and electrical properties, making them promising for applications in catalysis, solar cells, batteries, and superconductivity. Among 2D materials, transition-metal dichalcogenides (TMDCs) are noteworthy due to their tunable bandgap, high carrier mobility, and mechanical flexibility. Zirconium disulfide (ZrS2), a member of the TMDC family, stands out for its thermodynamic stability, environmental friendliness, and excellent thermoelectric properties. This paper provides an in-depth discussion of the synthesis of ZrS2 and its related materials, detailing various crystal structures and characterization methods. Additionally, the properties and applications of ZrS2 and its analogs are thoroughly reviewed, with a focus on their potential future developments
A geo-spatial approach to perceive the groundwater regime of hard rock terrain- a case study from Morappur area, Dharmapuri district, South India
No full textThe goal of the present study is to identify the groundwater regime of Morappur area at Dharmapuri district, India. The study area covers an area of 410 sqkm. The area belongs to a hard rock terrain where the primary porosity is feeble and the secondary porosity offered by fracture, joints and shear zones etc, contributes to the groundwater regime. The availability of surface water resources is sparse and hence the groundwater repositories are intensely utilized. In the current study area, the availability of groundwater is limited due to scanty rainfall and poor recharge. The entire study area underlain by hard crystalline rocks of Archaean age, Charnokite and Hornblende epidote gneiss are the main rock types encountered in the area. The over exploitation of these resources more than the adequate recharge has resulted to decrease in the groundwater level. In this context, it is very much important to identify and understand the groundwater regime of this area for the better groundwater monitoring and conservation of this precious resource. Remote Sensing and GIS are playing a vital role in the advancement of hydro-geological studies. The use of conventional methods alone has its own limitations in comprehending the groundwater regime of the area. The integrated study using remote sensing, field studies together with GIS has helped to understand the role of structural, lithological and geomorphic units in controlling the groundwater occurrence and movement in the present study area. Various thematic maps were prepared from the satellite images and they were integrated and incorporated in a GIS platform along with collateral information to study the groundwater regime of Morappur area. The outcome of this study clearly shows the importance of the geospatial studies in identifying the role of satellite imageries and geospatial techniques to understand the groundwater regime of a hard rock terrain
Politics of the temporary: migrant life in urban Malaysia
No full textIn this project, I look at an aspect of contemporary migration that has been largely sidelined and marginalized in mainstream debates, policy circles and research work – what happens to ‘host societies’ in the developing South that experience a rapid increase in numbers and diversity of urban populations owing to temporary migration. What are the implications of ‘temporariness’ on people’s everyday lives, practices, experiences, social environments and the urban spaces they inhabit? How does the presence and work of diverse groups of ‘temporary migrants’ alter and re-shape social, cultural and political dynamics of societies that have already been experiencing massive transformations and developments? What new forms, new practices, new networks, new hierarchies, new inequalities, and new strategies emerge in these contexts that might provide important knowledge from a transnational sociological perspective and critical studies standpoint? In order to address these broad questions, I looked at the experience of temporary labor migration in Malaysia, following a period of field research in the country. My concern that the agency of migrants is increasingly being looked at almost exclusively through an economistic, top-down lens dominated by development has prompted me to seek out the alternative experiences, conditions and practices that the Migration Development Nexus obscures and renders invisible. I sought to do this by looking at how 'temporariness' appears from below - from the perspectives of migrants, non-citizens and other inhabitants of an actual urban center in a fast-developing country of the Global South.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2017-12-01The student, Parthiban Muniandy, accepted the attached license on 2015-10-06 at 09:12.The student, Parthiban Muniandy, submitted this Dissertation for approval on 2015-10-06 at 09:18.This Dissertation was approved for publication on 2015-10-07 at 16:08.DSpace SAF Submission Ingestion Package generated from Vireo submission #8708 on 2016-03-08 at 11:05:08Made available in DSpace on 2016-03-08T17:21:44Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-10-07Embargo set by: Seth Robbins for item 91487
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Benchmark ab initio energy profiles for the gas-phase Y- + CH3X → CH3Y + X- (X,Y = F,Cl,Br): validation of hybrid DFT methods
No full textThe energetics of the gas-phase S(N)2 reactions Y- + CH3X- --> CH3Y + X- (where X,Y = F,Cl,Br), were studied using (variants on) the recent Wi and W2 ab initio computational thermochemistry methods. These calculations involve CCSD and CCSD(T) coupled cluster methods, basis sets of up to spdfgh quality, extrapolations to the one-particle basis set limit, and contributions of inner-shell correlation, scalar relativistic effects, and (where relevant) first-order spin-orbit coupling. Our computational predictions are in excellent agreement with experimental data where these have small error bars; in a number of other instances reexamination of the experimental data may be in order. Our computed benchmark data (including cases for which experimental data are unavailable altogether) are used to assess the quality of a number of compound thermochemistry schemes such as G2 theory, G3 theory, and CBS-QB3, as well as a variety of density functional theory methods. Upon applying some modifications to the level of theory used for the reference geometry (adding diffuse functions, replacing B3LYP by the very recently proposed mPW1K functional [Lynch, B. J.; Fast, P. L.; Harris, M.; Truhlar, D. G. J. Phys. Chem. A 2000, 104, 4811]), the compound methods appear to perform well. Only the "half-and-half" functionals BH&HLYP and mPWH&HPW91 and the empirical mPW1K functional, consistently find all required stationary points; the other functionals fail to find a transition state in the F/Br case. BH&HLYP and mPWH&HPW91 somewhat overcorrect for the tendency of B3LYP land, to a somewhat lesser extent, mPW1PW91) to underestimate barrier heights. The Becke97 and Becke97-1 functionals perform similarly to B3LYP for the problem under study, while the HCTH and HCTH-120 functionals both appear to underestimate central barriers. HCTH underestimates complexation energies; this problem is resolved in HCTH-120. mPW1K appears to exhibit the best performance of the functionals considered, although its energetics are still inferior to the compound thermochemistry methods. mPW1K, however, appears to be very suitable for generating reference geometries for more elaborate thermochemical methods in kinetics applications
2,4-Bis(4-ethoxyphenyl)-7-methyl-3-azabicyclo[3.3.1]nonan-9-one
No full textThe molecule of the title compound, C25H31NO3, exists in a twin-chair conformation with an equatorial orientation of the 4-ethoxyphenyl groups, as observed for its ortho isomer [Parthiban, Ramkumar, Park & Jeong (2011b), Acta Cryst. E67, o1475–o1476]. The methyl and 4-ethoxyphenyl groups are also equatorially oriented on the bicycle, as in the ortho analogue. In particular, although the cyclohexanone ring deviates from an ideal chair, the piperidone ring is closer to an ideal chair, whereas in the ortho isomer both rings are significantly puckered and deviate from ideal chairs. The 4-ethoxyphenyl groups on both sides of the secondary amine group are oriented at an angle of 26.11 (3)° with respect to each other, but the 2-ethoxyphenyl groups in the ortho isomer are oriented by less than half this [12.41 (4)°]. In contrast to the absence of any significant interactions in the crystal packing of the ortho isomer, the title compound features N—H...O interactions, linking the molecules along the b axis
Reciprocity and R&D Search: Applying the Behavioral Theory of The Firm to a Communitarian Context
No full textDo shareholders or stakeholders appropriate the rents from corporate diversification?: The influence of ownership structure
No full textThe effective use of virtualization for selection of data centers in a cloud computing environment
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