سخنران: ک. حاجیان، دانشگاه صنعتی خاورمیانه ترکیه

14 مرداد 1399
14:00 تا 15:00

Abstract:

In flat spacetime, Poincare group is the Lie group of linear transformations on space-time which keeps the speed of light invariant. This is the corner-stone of special relativity. However, in theories defined such that are only asymptotically flat, it has been shown that the group of physical transformations is larger than Poincare, and it is called the BMS group. I will show that this group of transformations does not keep the speed of light invariant. As a result, one can use this physical observable to distinguish geometries which are related by a BMS transformation to each other, i.e the soft hairs. Moreover, this observable is related to the gravitational memory effect which had been used as an observable for soft hairs.

In my talk, first I will review Asymptotic Symmetry Group (ASG) analysis, BMS_4 group and gravitational memory effect. Then, I will present the results of the analysis of speed of light in this context.


Skype link for emergency

SkypeLink: https://join.skype.com/cm7iyEUWJVCf

سخنران: شانت باغرام
دانشگاه صنعتی شریف

15 مرداد 1399
13:30 تا 15:00

این سمینار روز چهارشنبه 15 تیر ماه ساعت 13:30 به صورت آنلاین برگزار می شود.

سخنران: آ.س. کاظمی، دانشگاه علم و صنعت ایران

15 مرداد 1399
14:00 تا 15:00

Abstract:

While carbon based materials attract a lot of attention for their remarkable physical and mechanical properties, it is necessary to modify their surface chemistry and wettability with functionalization for successful interaction of these materials with the surrounding medium like air, water and bio-fluids. A functionalization treatment, even small, can drastically alter the physical and chemical properties of carbon-based materials. Among strategies for functionalization, covalent sidewall functionalization is based on the rehybridization of a sp2 carbon atom into a sp3 configuration, is more robust, induces important modifications in the materials properties and exhibits a large range of applications such as broadband electromagnetic devices, ion storage devices, supercapacitor electrodes, sensors, composites, solid lubricants, and water desalination. Here, carbon-based membranes, initially designed and fabricated for water desalination, were functionalized with H2 and SF6 plasma treatments. Interesting morphological impacts of functionalization time and agent on the membranes were captured by molecular dynamic simulations, FESEM imaging, EDAX analyses and Raman spectroscopy. Above and beyond, water contact angle measurements revealed tuneability between hydrophobicity and hydrophilicity of the functionalized membranes. Electrical conductivity measurements further reflected the potential of functionalized carbon based membranes in holding back the salt, allowing fast transport of water, cancelling the conventional trade-off between selectivity and permeability, and presented these materials as candidates for new generation of nanomaterials in water desalination.

چهارشنبه، ۱۵ مرداد ۱۳۹۹

Time: 14:00-15:00

To join the webinar, please follow this link:
https://www.skyroom.online/ch/schoolofphysics/condensed-matter-and-statistical-physics
and log in as guest.

Organized by: Condensed Matter and Statistical Physics Group, School of Physics (IPM)

Queries about this event should be addressed to Dr. A. Faridi at azadeh.faridi@ipm.ir

سخنران: غلامحسین حقیقت، پژوهشگاه دانش های بنیادی

15 مرداد 1399
11:00 تا 12:00

Meeting's link: https://www.skyroom.online/ch/ipm-particles/school-of-particles-and-accelerators-weekly-meeting

Indico: https://indico.particles.ipm.ir/indico/event/367