Showing items 1 - 7 of 7

Your selections:

A molecular dynamics investigation of the temperature effect on the mechanical properties of selected thin films for hydrogen separation

Atomistic Simulations of Interfacial deformation and bonding mechanism of Pd-Cu Composite Metal Membrane using Cold Gas Dynamic Spray Process

Development of composite metal membrane using cold gas dynamic spray for hydrogen separation : a numerical simulation approach

Development of palladium nanoparticles deposition on a copper substrate using a molecular dynamic (MD) simulation : a cold gas dynamic spray process

Formation of glycine in the interstellar medium : computational studies on various possible reaction paths

  • Authors: Nhlabatsi, Zanele Precious
  • Date: 2017
  • Subjects: Cosmochemistry , Astrophysics , Interstellar matter , Molecular dynamics
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/233977 , uj:23900
  • Description: Ph.D. (Chemistry) , Abstract: “How the most essential life elements, i.e., amino-acids, were formed in the interstellar medium (ISM)?” and “What are their roles in the evolution of life in our solar system?” are the two most intriguing questions, which are not yet answered exclusively as indicated in the works of many researchers. Among all the natural amino-acids, glycine (H2N-CH2-COOH) is not only an important biologically active molecule but also is the simplest as well as smallest amino-acid that can be found in all the biological entities found in the earth. The era of the astronomical search for glycine began as soon as the laboratory spectra for it were made available in 1978. Since then astrophysicists have been searching for this glycine in the ISM and many decades have been passed but still without any success. This is in spite of the fact that many amino-acid including the glycine have been found on meteorites, and moreover the distinct isotopic signature of those amino-acids are indicative of their extraterrestrial origin.However, detection of glycine in the interstellar medium is still ambiguous and the major problem arising in the analysis of a large cluster of weak lines collected through various high resolution telescopes. In this present work, using computational calculations many possible as well as favourable reaction paths, which can lead to the formation of Glycine in the interstellar conditions, have been investigated. Detailed mechanisms of those possible reaction paths have been investigated and also aptness of their feasibilities in the ISM has been discussed in the light of the prevailing interstellar conditions. From the mechanistic analysis of these possible reaction paths, it was observed that two of them show concerted type of mechanism, whereas others proceed through multi-stepped paths. One such concerted reaction discussed in this thesis encompasses the reaction of CH2=NH, CO and H2O leading to the formation of glycine. It was observed that this reaction...
  • Full Text:

Reaction profiles of some nitrogen bearing species in the interstellar medium : a computational study

  • Authors: Bhasi, Priya
  • Date: 2017
  • Subjects: Cosmochemistry , Interstellar matter , Astrophysics , Molecular dynamics
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/233963 , uj:23899
  • Description: Ph.D. (Chemistry) , Abstract: Interstellar chemistry is one of the areas of research which is constantly growing in the field of astrochemistry. With the advent of the Herschel Space Observatory, a new window has opened up in the field of spectroscopic researches related to space chemistry or interstellar chemistry. It has enabled the detection of many imortant molecules, especially many nitrogen containg molecules like, NH, NH2 and NH3, even in the cold envelopes of protostars. Observations of many new nitrogen containing species and some of the already detected nitrogen containing species in extreme cold temperatures, have brought many new constraints in the field of interstellar research. In particular, such a situation gives the opportunity to revisit the study to the chemistry of nitrogen in the interstellar medium, as the knowledge of nitrogen bearing species in interstellar medium is exceptionally important, as they can act as precursors for the formation of many pre-biotic molecules. On the other hand nitrogen has a peculiar chemistry that completely differs from those of carbon and oxygen, and also at the same time nitrogenated species are used as suitable probes for understaning the chemistry of the interstellar medium over a wide range of conditions. For the active nitrogen chemistry to get materialized in the interstellar medium, one needs to have a very large elemental nitrogen partitioning. Elemental nitrogen partitioning largely affects the active nitrogen chemistry in the ISM. One of the major components in the elemental nitrogen partitioning is the molecular form of nitrogen N2, which is largely unreactive due to the strong triple bond (large bond dissociation energy). On the other side the second component which constitutes the more labile forms of nitrogen (combinations of...
  • Full Text:

Using the ultra-relativistic quantum molecular dynamics (UrQMD) model to extract the thermal conductivity transport coefficient of hadron gas

  • 1
  • Disclaimer
  • Privacy
  • Copyright
  • Contact