Physics Colloquia Fall 2015 (usually Fridays 2:00 PM in SE 319)
Titles link to the abstracts.
Date 
Speaker 
Title 
Oct 16 
Hadi Mohammadi Gorak, FAU 

Thursday, Oct 22 
Larry A. DeWerd, University of Wisconsin 

Thursday, Oct 29 
Maximilian Hanusch, FAU 

Nov 6 
Yang Wang, Pittsburgh Supercomputing Center 

Nov 13 
Oscar Curet, FAU 

Nov 20 
Pramod Acharya, FAU 

 
Colloquium Abstracts
Dynamics of an Active Nematic Elastomer

Hadi Mohammadi Gorak, Oct 16 
Nematic elastomers are crosslinked polymer gels (e.g. rubbers) that
show long range orientational orders. They are known for the soft elasticity
that arises from the Goldstone mode of the rotational symmetry being
spontaneously broken. In this talk, we explore the hydrodynamics of a
nematic elastomer driven out of equilibrium by an active stress that is
proportional to the alignment tensor. In particular, we discuss the mode
structures of active Nematic elastomers and their stability. We find that the
active stress, under suitable circumstances, renders the transverse sound
modes unstable. Furthermore, we discuss various correlation functions and
compare them with experimental measurements of the fluctuations of a
metaphase spindle.


Calibration by the AAPM Accredited Dosimetry Calibration Laboratories (ADCLs) is More than a Number

Larry DeWerd, Oct 22 
The Accredited Dosimetry Calibration Laboratories (ADCL) were started by the American Association of Physicists in Medicine (AAPM) to maintain standards for dosimetric measurements for accurate treatment of patients. A review of the metrology (science of measurement) for the calibration laboratories will be reviewed. The laboratories work in tenths of a percent so that the clinic can maintain their dosimetric levels within 2%. The accuracy and precision of the measurements and the primary standards used will be given as it affects the local medical physicist and the patient. An understanding of the equipment that is used and the mistreatment of it will be given with an explanation of detection of problems, before they are serious.


Symmetry Reduction and Quantum Gravity

Maximilian Hanusch, Oct 29 
Symmetries play an important role in physics, as they usually allow to simplify the equations of a given theory, and thus, make it easier to find solutions. In particular, given a complicated new theory, it might drastically simplify for highly symmetric configurations, making it much easier to make predictions which can be checked by experiments. In this talk, we will discuss symmetries in the framework of loop quantum gravity, an approach to construct a theory, unifying quantum mechanics and general gravity.


Petascale Computing for Ab initio Electronic Structure Calculations

Yang Wang, Nov 6 
The density functional theory based ab initio electronic structure calculation is a widely used practice in computational materials science, and is also one of the most important application areas in high performance computing. In this presentation, I will explain the latest efforts in accelerating the electronic structure calculations by using petascale computing technologies. I will give a brief review of the fullpotential multiple scattering theory approach to the ab initio electronic structure calculation, also known as the KorringaKohnRostoker (KKR) electronic structure calculation method, and use it as an example to show how we explore the massive compute core resources in a petascale computing environment, and implement the functionality that enables to move the compute intensive tasks to coprocessors for accelerating the floating point operations. I will show the petascale applications of the multiple scattering theory method, and discuss its computational performance in a state of the art high performance computing environment.


The fluid mechanics of flexible and underactuated fins

Oscar Curet, Nov 13 
Effective control of flexible structures can enhance the functionality and performance of engineering systems such as, propulsion and lifting surfaces, mechanical tools, robotics, electronics, as well as, biomedical, and mixing devices. A clear limitation of these flexible structures is that the mechanical design and control of propulsive forces are highly complex. The potential use of underactuated undulating fins that take advantages of natural dynamics of the fluidstructure interaction can greatly reduce the complexity of the problem. In this seminar, I will present our recent work of two bioinspired problems: hydrodynamics of undulating fins for highly maneuverable vessels and the fluid mechanics of around the pectoral fins of larva zebrafish and its potential to enhance mixing at low Reynolds number.


