Abstract

There is a great significance of scientific research in everyday life; from explaining the world around to inventing machines, computers, and the internet. We know what we know most likely because someone somewhere was curious about it and decided to research about it. I believe all of us are born as a scientist. Our effort as science educator should be towards helping and nurturing the curiosity of kids well into their high school and beyond. This motivated me to return from the US and establish "STEM Research Teaching Center" with the goal of spreading and creating awareness toward scientific research. Through this talk, I will share my experience in the field of scientific research as a student, employee, and entrepreneur in two contrasting halves of the globe.

Abstract

We have performed the first-principles calculations to study the stability, geometrical structure and electronic properties of pure graphene, MoS2 monolayer and MoS2/Graphene bilayer hetero-structure (MGBHs) based in the Density Functional Theory (DFT) with van der Waals (vdW) interactions in the DFT-D2 approach under Generalized Gradient Approximation (GGA), implemented by the Quantum ESPRESSO. Further we have studied the possibility of using these materials as energy storage devices like storing hydrogen and methane. Our investigations reveal that bare graphene is not suitable material to store hydrogen (methane) and metal decorated, graphene is suitable to use as a device to store hydrogen(methane).

Abstract

Interaction of photons with materials is a subject of great importance in the condensed matter systems. Photons impinging upon the material sample can induce several interesting effects such as surface plasmonics, and index of refraction change. In noble metals such as gold and silver, plasmons are pronounced more than in other metals in visible to near infrared region depending upon the size and shape of the nanostructures. In the Dirac system such as graphene and 3D topological insulator, plasmonics effect can be observed in the infrared to THz regime. In this presentation, some of the interesting effects induced due to plasmons in the noble metal and the Dirac systems will be presented. Starting from introduction of the Dirac system, origin of the surface plasmons arise due to the massless particles will be presented.

Dirac systems can be used for the semiclassical and quantum information processing. In this presentation, as a part of applications of our results, information processing scheme using 3D TI quantum dot will be presented. Finally, the presentation will be wrapped up with the lasing action arises due to the surface plasmons, known as SPASER (Surface Plasmons Amplification by Stimmulated Emmision of Radiation).

Abstract

Greenhouse gas emissions have committed the world to a range of adverse and potentially catastrophic effects. Based on an analysis of thousands of Scientific publications, the Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC) determined that global warming as “unequivocal” and that human activities are “very likely” to be the cause of it. The problems of climate change emerged with the beginning of industrial era. Since preindustrial era, the atmospheric concentration of green house gases increased due to human activities reaching their highest record level in the 1990s.

Though Nepal is one of the least responsible countries to cause climate change, it is severally effected by climate change. Based on available data it is found that the average warming in annual temperature between 1977 and 2000 was 0.06°C/yr. The warming is found to be more pronounced in the higher altitude regions of Nepal such as middle-mountain and Himalaya, while the warming is significantly lower in Terai and Siwalik regions. The talk will focus on recent observations on climate change, greenhouse effect, and the ways to minimize adverse effects of climate change.

Abstract

Understanding science in school and university levels can be greatly improved by introducing courses which have parallel drags of theory and experiments. A single experiment, sometimes, can tell a lot about complicated concepts in physics in very simple and entertaining way. For example, an LCR series and parallel circuit experiment can be used to demonstrate variety of concepts in physics such as impedance, phase relations, resonance, working principles of detectors etc. The talk will focus on recent trends and practices in experimental courses in Tribhuvan University, including some of the very new kinds of experiment introduced such as verification of Dirac Delta Function using simple computer code.