TC group seminars

The Theoretical Chemistry research group at the Department of Chemistry is organising a series of seminars that are usually held once every two weeks at the location and time specified below. The TC seminars are open to everyone. To schedule a seminar or get more information about the TC seminars, please contact Raffaela Cabriolu.

Location: Realfagbygget, D3-114 (Onsagerrommet)


Wednesday 16.01.2019

Prof. Jocelyne Vreede from the Computational Chemistry group at the Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands, will present a seminar on "Modeling protein-mediated organization of DNA in bacteria".

N.B. The seminar will be held at 13.00 In ONSAGER room.

Wednesday 16.01.2019

Prof. Jocelyne Vreede from the Computational Chemistry group at the Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands, will present a seminar on "Modeling protein-mediated organization of DNA in bacteria".

N.B. The seminar will be held at 13.00 In ONSAGER room.

Prof. Jocelyne Vreede (associate professor)

 

"My simulations of protein unfolding need computing power - lots of computing power. My calculations concern molecules made up of 30,000 atoms that change shape over the course of a million little steps. So that takes rather a lot of computing power."

"When I first started studying chemistry I had never even worked on a computer. I was still writing up all my papers by hand. And I had never imagined myself in a research job involving entire days spent building models. It was lab work I wanted to pursue. But I enrolled in a few subjects dealing with molecular simulations and enjoyed them so much that I wanted to keep going in that direction."

"After I obtained my PhD in the Microbiology research group at SILS (Swammerdam Institute or Life Sciences), I started working as a postdoc researcher in the Computational Physics and Chemistry group at HIMS (Van 't Hoff Institute for Molecular Sciences). My work there focused on a bacterial protein called Photoactive Yellow Protein, or PYP for short. The way this protein behaves is an illustration of observing signals on a molecular scale. PYP acts something like a trigger. It can detect harmful UV radiation and sets off a series of reactions in response. This response is prompted by a change in the protein's internal structure, which puts it into what is known as the signal state. Of course, the protein had already been sequenced, and various experiments had also revealed exactly how the protein was folded in space."

"When you have a set of particles, they "feel" each other, as it were. I describe each bond, the angle of the atoms' placement relative to each other and the torsions. Next, I factor in the electrostatic interactions - positively charged particles repel each other; positive and negative attract - and the Van der Waal interactions, which quickly decay as distance grows. The result is a model which I refer to as a ‘force field': an extensive set of interactions between the particles inside the molecule."

"It takes no more than a few milliseconds for PYP to unfold. The structural changes that occur are modelled on the basis of the force field description and use increments of femtoseconds. That means I would need to make around 1011 calculations to reconstruct the entire process of unfolding - not exactly time-efficient, considering that if it took me one second to do each increment, the entire calculation would take 15,000 years. Luckily, there are a few tricks I can use to speed up the reaction, such as using a higher temperature. For a protein like PYP to unfold, there has to be some sort of activation pushing it to cross the barrier from a stable state. That barrier is lower at higher temperatures, when atoms move much faster. Consequently, the simulation of the unfolding speeds up significantly. I've set up 64 unfolding simulations for PYP, each at a different temperature. By switching these temperatures, I was able to reconstruct how the molecule would look if it had been unfolding at room temperature. In the final model, the light-activated group had moved to the protein's exterior and several helixes had uncoiled. A number of other researchers carried out additional experiments with a mutant of PYP to check whether this conformation was valid. This mutant protein has a more stable signal state, enabling my colleagues to study it using an experimental technique. Their findings validate the PYP conformation I found."

"But one major question remained: What is the actual course of the unfolding process? To find out, I used a method called Transition Path Sampling. This is a simulation technique designed around 10 years ago by my group's head researcher, Prof. Peter Bolhuis, whilst working at Berkeley. It starts off on a reaction path from another simulation, in this case a high temperature unfolding. Naturally that's not the real reaction path, but it is a reasonable guess. New reaction paths can also be calculated on the basis of this reaction path at any given point in the conformational change. The algorithm automatically saves the reaction paths that would put the protein in either the inactive or signal state. Reaction paths leading nowhere are rejected by the program. The successful reaction paths can be used to generate new paths in turn, with the process repeating until a path representing the probable unfolding is found. With 125 amino acids, PYP is a comparatively large protein to use in simulations, as it unfolds in a series of steps. Moreover, it is a molecule that is biologically relevant. My article on the unfolding even made it into the columns of the reputable journal Proceedings of the National Academy of Sciences (PNAS)."

"I have now widened my focus to include transitions in biological proteins that are even larger and more complex than PYP. In 2008 I received a Veni grant from the Netherlands Organisation for Scientific Research (NWO) for this research. One of my current projects is on so-called ‘coiled coils': two helix-shaped proteins that are coiled around each other."

"It's logical that simulations do not always hit their mark right away. One of my programs might have a bug, for example, or I could make an error when inputting a bond. That's just as much a part of research as errors you make in the lab. It is the theory that is really key in this work. You always have to keep thinking about the chemical reality. Your steps have to be logical. In the end, a simulation program is never more than a tool."

Friday 14.12.2018

Prof. Jocelyne Vreede from the Computational Chemistry group at the Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands, will present a seminar on "Modeling protein-mediated organization of DNA in bacteria".

N.B. The seminar will be held at 13.00 In ONSAGER room.

 

Friday 14.12.2018

Prof. Jocelyne Vreede from the Computational Chemistry group at the Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Netherlands, will present a seminar on "Modeling protein-mediated organization of DNA in bacteria".

N.B. The seminar will be held at 13.00 In ONSAGER room.

 

Abstract:

Asphaltenes are the heaviest component of crude oil, causing the formation of a stable oil–water emulsion. Even though asphaltenes are known to behave as an emulsifying agent for emulsion formation, their arrangement at the oil–water interface is poorly understood. We investigated the effect of asphaltene structure (island type vs archipelago type) and heteroatom type (Oxygen-O, Nitrogen-N, and Sulfur-S) on their structural behavior in the oil–water system. Out of six asphaltenes studied here, only three asphaltenes remain at the oil–water interface while others are soluble in the oil phase. Molecular orientation of asphaltene at the interface, position, and angle of asphaltene with the interface has also been determined. We observed that the N-based island type asphaltene is parallel, while the O-based island type asphaltene and N-based archipelago type are perpendicular to the interface. These asphaltene molecules are anchored at the interface by the heteroatom. The S-based asphaltenes (both island and archipelago type) and O-based archipelago type asphaltenes are soluble in the oil phase due to their inability to form a hydrogen bond with water and steric crowding near the heteroatom. This study will help in understanding the role of asphaltenes in oil–water emulsion formation based on its structure and how to avoid it.

https://pubs.acs.org/doi/10.1021/acs.energyfuels.8b01648

MOFs:

https://www.nakulrampal.com/research

 

Monday 19.11.2018

Dr. J. Prehl from "Institut für Physik" in Chemnitz in Germany will present a seminar on "Modeling the structure formation process of twin polymerization".

N.B. The seminar will be held at 10.00am In ONSAGER room.

Monday 19.11.2018

Dr. J. Prehl from "Institut für Physik" in Chemnitz in Germany will present a seminar on "Modeling the structure formation process of twin polymerization".

N.B. The seminar will be held at 10.00am In ONSAGER room.

ABSTRACT:

Twin polymerization [1] represents a new synthesis route to create nano-porous hybrid materials for a large number of different compositions containing organic and inorganic structure domains of 0.5 to 3 nm. Although first theoretical and experimental investigations have been performed, the open question still remains: How does the structure formation process of twin polymerization, yielding these interweaved organic-inorganic nanoporous hybrid materials, takes place in detail? Understanding the occurring effects and processes of the structure formation opens up the possibility to design (organic and/or inorganic) nanoporous materials with desired properties for industry. E.g. nanoporous materials are of great interest in applications like gas filter systems, catalyst or fuel cells.
In this framework we investigate different approaches on different length scales, i.e. coarse grained reactive bond fluctuation models [2], reaction kinetics models [3], reactive molecular dynamics [4], and density functional theory calculations [5]. Based on this broad range of methods we discuss our insights to the reaction mechanism itself, the resulting structure formation process, corresponding influence factors and its relation to experimental data.

References
[1] T. Ebert, A. Seifert, S. Spange, Macromol. Rapid Commun. 2015, 36(18):1623–1639
[2] C. Huster, K. Nagel, S. Spange, J. Prehl, Chem. Phys. Lett. accepted
[3] J. Prehl, R. Masser, P. Salamon, K. H. Hoffmann, J. Non-Equilib. Thermody. 2018
43(4):347–357
[4] J. Prehl, T. Schönfelder, J. Friedrich, S. Spange, K. H. Hoffmann, J. Chem. Phys. C 2017
121(29): 15984–15992
[5] I. Tchernook, J. Prehl, J. Friedrich, Polymer 2015, 60:241–251.

Thursday 07.06.2018

Prof. R.O. Jones from "Forschungszentrum Juelich" in Germany will present a seminar in "Density functional theory: its origins, present status, and future".
 

N.B. The seminar will be held at 10.30 In ONSAGER.

Thursday 07.06.2018

Prof. R.O. Jones from "Forschungszentrum Juelich" in Germany will present a seminar in "Density functional theory: its origins, present status, and future".
 

N.B. The seminar will be held at 10.30 In ONSAGER.

ABSTRACT:
 
In little more than 20 years, the number of applications of the density functional (DF) formalism in chemistry and materials science has grown in an astonishing fashion.
The number of publications alone shows that DF calculations make up a huge success story, and younger scientists are often surprised to learn that the widespread application of DF methods, particularly in chemistry, began only after 1990. This is indeed
unexpected, because the origins are usually traced to the papers of Hohenberg, Kohn, and Sham more than a quarter of a century earlier. I take 1990 as fixed point, review the development of density related methods back to the early years of quantum mechanics,follow the breakthrough in their application after 1990, and give two examples from biochemistry and materials science that were beyond our dreams in 1990. I discuss the reasons why -- fifty years after its modern formulation and after two decades of rapid expansion -- some of the most cited practitioners in the field are concerned about its future.
 
 

Thursday 15.03.2018

12:15 Prof. Smit from LSMO at EPFL (École polytechnique fédérale de Lausanne) will present the seminar "The Materials Genome in Action: understanding the mechanical properties of metal organic frameworks".

 

N.B. The seminar will be held at Elektro B EL4.

Thursday 15.03.2018

12:15 Prof. Smit from LSMO at EPFL (École polytechnique fédérale de Lausanne) will present the seminar "The Materials Genome in Action: understanding the mechanical properties of metal organic frameworks".

 

N.B. The seminar will be held at Elektro B EL4.

Professor Berend Smit is Full Professor of Chemical Engineering at the School of Basic Sciences..
Berend Smit received an MSc in Chemical Engineering in 1987 and an MSc in Physics both from the Technical University in Delft (the Netherlands). He received in 1990 cum laude PhD in Chemistry from Utrecht University (the Netherlands). He was a (senior) Research Physicists at Shell Research from 1988-1997, Professor of Computational Chemistry at the University of Amsterdam (the Netherlands) 1997-2007. In 2004 Berend Smit was elected Director of the European Center of Atomic and Molecular Computations (CECAM) Lyon France. In 2007 he was appointed Professor of Chemical Engineering and Chemistry at U.C. Berkeley and Faculty Chemist at Materials Sciences Division, Lawrence Berkeley National Laboratory.
Since July 2014 he is director of the Energy Center and  full professor at EPFL. 
Berend Smit's research focuses on the application and development of novel molecular simulation techniques, with emphasis on energy related applications. Together with Daan Frenkel he wrote the textbook Understanding Molecular Simulations and together with Jeff Reimer, Curt Oldenburg, and Ian Bourg the textbook Introduction to Carbon Capture and Sequestration.

Thursday 07.12.2017

Joint seminars:

13.30 : Prof. Ahlquist from Royal Institute of Technology, Stockolm : "Water oxidation catalyst simulation in realistic environment".

14.15 : Prof. Jensen from the department of Chemistry at the University of Bergen: "Computational design of functional transition-metal compounds: Methods and examples".

Thursday 07.12.2017

Joint seminars:

13.30 : Prof. Ahlquist from Royal Institute of Technology, Stockolm : "Water oxidation catalyst simulation in realistic environment".

14.15 : Prof. Jensen from the department of Chemistry at the University of Bergen: "Computational design of functional transition-metal compounds: Methods and examples".

"Water oxidation catalyst simulation in realistic environments”

Thursday 09.11.2017

Prof. Steven Holdcroft from the department of Chemistry at the University of Salford, U.K.:

"Hydrocarbon, Solid Polymer Electrolytes for Acidic and Alkaline Electrochemical Devices: Advances and Transport Properties"

Thursday 09.11.2017

Prof. Steven Holdcroft from the department of Chemistry at the University of Salford, U.K.:

"Hydrocarbon, Solid Polymer Electrolytes for Acidic and Alkaline Electrochemical Devices: Advances and Transport Properties"

Abstract and references: 

Perfluorinated proton-exchange polymers form the basis of standard high-performance PEMFCs but difficult synthetic chemistry hampers further materials development. Hydrocarbon proton-exchange materials, on the other hand, are founded on well-established and versatile synthetic chemistry that allows for rapid materials development, and offer a less expensive alternative to perfluorinated polymers. In the corollary case of Anion Exchange Membrane Fuel Cells, the search continues for an alkaline-stable, polymeric hydroxide-conducting medium. Solutions to these challenges require the undertaking of rigorous systematic studies on model polymers and representative materials of known and controllable molecular structure and preferred nano-morphology. In this presentation, the evolution and properties of unique proton- and hydroxide-conducting polymers will be described together with mass transport phenomenon of PEMs and AEMs that might be of interest to the NTNU group.

References:

  • Structurally-Defined, Sulfo-Phenylated, Oligophenylenes and Polyphenylenes”, J. Am. Chem. Soc, 137 (2015) 12223-12226.

  • Hydroxide-Stable Ionenes”, ACS Macro Letters, 3 (5) (2014) 444-447.

  • "Poly(phenylene) and m-Terphenyl as Powerful Protecting Groups for the Preparation of Stable Organic Hydroxides”, Angewandte Chemie, 55 (2016), 4818-4821.

  • The Control and Effect of Pore Size Distribution in AEMFC Catalyst Layers”, J. Electrochem. Soc, 163 (5) (2016) F1-F6.

  • Fuel Cell Catalyst Layers” Chem. Mater., Invited perspective commemorating 25th year of Chemistry of Materials, 2014, 26 (1), 381–39.

  • "Thickness dependence of water permeation through proton exchange membranes”, J. Membr. Sci. 364 (2010) 183–193.

  • Electrochemical reduction of dissolved oxygen in alkaline, solid polymer electrolyte films, J. Amer. Chem. Soc. 138 (2016) 15465-15472.


 

Thursday 12.10.2017

Prof. Jaakko Akola "DFT-MD simulations of phase-change materials and crystallisation":

 

Note: this seminar will be held at 13:00 !

Thursday 12.10.2017

Prof. Jaakko Akola "DFT-MD simulations of phase-change materials and crystallisation":

 

Note: this seminar will be held at 13:00 !

The main research topics of Prof. Jaakko Akola  are:

  • Amorphous semiconductor materials in nonvolatile memory applications, especially chalcogenide alloys (DVD-RAM, DVD-RW, Blu-ray Disc, Phase-change RAM, Conductive-bridging RAM)
  • Glasses in general: Novel oxide-based materials, chalcogens, pnictides, etc.
  • Noble metal nanoparticles (Au, Ag, Pt, Pd) with various coatings and environments (surface, solution and biological environment)
  • H2020-NMP project CritCat: Size-selected metal clusters as replacements of the Platinum Group Metals in heterogeneous and electrocatalysis (hydrogen energy, CO2 chemistry)
  • Intermetallic alloys based on aluminum; clustering, precipitate formation and hardening effects

 

For more information please refer to the website: https://www.ntnu.edu/employees/jaakko.akola.

Thursday 28.09.2017

Prof. Titus van Erp : "Rare event simulations reveal subtle key steps in aqueous silicate condensation "

 

Note: this seminar will be held at 13:00 !

Thursday 28.09.2017

Prof. Titus van Erp : "Rare event simulations reveal subtle key steps in aqueous silicate condensation "

 

Note: this seminar will be held at 13:00 !

Abstract:

A replica exchange transition interface sampling (RETIS) study combined with Born–Oppenheimer molecular dynamics (BOMD) is used to investigate the dynamics, thermodynamics and the mechanism of the early stages of the silicate condensation process. In this process, two silicate monomers, of which one is an anionic species, form a negatively charged five-coordinated silicate dimer. In a second stage, this dimer can fall apart again, forming the original monomers, or release a water molecule into the solution. We studied the association and dissociation reaction in the gas phase, and the dissociation and water removal step in the aqueous phase. The results on the aqueous phase dissociation suggest two possible mechanisms. The breakage of the bond between the intermediate oxygen and the five-coordinated silicon is sometimes accompanied by a proton transfer. After dissociation into silicate monomers, the anionic monomer is either the previously four-coordinated silicon or the previously five-coordinated silicon depending on whether the hydrogen transfer occurs or not. Our results show that the mechanism of proton transfer is highly predominant. Water removal simulations also show two possible mechanisms distinguished by the proton transfer reaction path. Proton transfer can occur either via a direct or via a water mediated reaction step. The calculations reveal that although both mechanisms contribute to the water removal process, the direct proton transfer is slightly favorable and occurs roughly in six out of ten occasions.

Physical Chemistry, Chemical Physics - PCCP. vol. 19.

Thursday 11.05.2017

Dr. Elisa Magnanelli : "The Nasal Geometry of the Reindeer Nose Gives Energy-Efficient Respiration"

 

Note: this seminar will be held at 13:00 !

Thursday 11.05.2017

Dr. Elisa Magnanelli : "The Nasal Geometry of the Reindeer Nose Gives Energy-Efficient Respiration"

 

Note: this seminar will be held at 13:00 !

"The Nasal Geometry of the Reindeer Nose Gives Energy-Efficient Respiration"

Abstract:

"Reindeer in the arctic region live under very harsh conditions, and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating fur, the reindeer nasal mechanism for heat and mass exchange during respiration plays a fundamental role. We present a dynamic model to describe the heat and mass transport that takes place inside the reindeer nose, where we account for the complicated geometrical structure of the subsystems that are part of the nose. The model correctly captures the trend in experimental data for the temperature, heat and water recovery in the reindeer nose during respiration. As a reference case, we model a nose with a simple cylindrical-like geometry, where the total volume and contact area are the same as those determined in the reindeer nose. A comparison of the reindeer nose with the reference case shows that the nose geometry has a large influence on the velocity, temperature and water content of the air inside the nose. For all investigated cases, we find that the total entropy production during a breathing cycle is lower for the reindeer nose than for the reference case. The same trend is observed for the total energy consumption. The reduction in the total entropy production caused by the complicated geometry is higher (up to -20%) at more extreme ambient conditions, when energy efficiency is presumably more important for the maintenance of energy balance in the animal. In the literature, a hypothesis has been proposed, which states that the most energy efficient design of a system is characterized by equipartition of the entropy production. In agreement with this hypothesis, we find that the local entropy production during a breathing cycle is significantly more uniform for the reindeer nose than for the reference case. This suggests that natural selection has favored designs that give uniform entropy production when energy efficiency is an issue. Animals living in the harsh arctic climate, such as the reindeer, can therefore serve as inspiration for a novel industrial design with increased efficiency."

Reference to paper: Elisa Magnanelli, Øivind Wilhelmsen, Mario Acquarone, Lars P. Folkow, and Signe Kjelstrup. "The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration." Journal of Non-Equilibrium Thermodynamics 42, no. 1 (2017): 59-78.

Friday 28.04.2017

Natalya Kizilova: from Kharkov National University: 

"Plant evolution, entropy production and the constructal law"

Note: this seminar will be held at 10:40 !

Friday 28.04.2017

Natalya Kizilova: from Kharkov National University: 

"Plant evolution, entropy production and the constructal law"

Note: this seminar will be held at 10:40 !

The evolution of plants has numerous aspects from molecular biophysics to intercommunication between the species. In this presentation the evolution of the long-range liquid delivering transport systems in high plants is be discussed. The transport systems are presented by xylem and phloem vessels formed by bunches of microtubes with permeable walls. The xylem system provides ascending flow of the water solution of mineral and organic components from roots, while the phloem system supplies the inverse flow of the phloem sap from the photosynthesizing leaves towards seeds, flowers and roots. Both systems form quite freaky pipelines in the plant roots, stems, branches, leaves and flowers. In the plant leaves those systems form several typical patterns which are called venations. During the plant evolution the design of the venation type changed, though all the types could be found in modern high plants. In this presentation the fluid flows in the modeled distributed networks of the tubes with permeable walls corresponded to main known types of the leaf venations are studied. Different shapes of the leaf blade are also taken into account. The flow parameters, energy expenses and entropy production are computed. It is shown the direction of evolution is aimed at gradual decrease in the entropy production that corresponds to the constructal law. Nevertheless the samples that are less ‘optimal’ in the meaning of the efficiency of the liquid delivery systems may benefit from more optimal ‘solutions’ at another level (biochemical, biophysical, etc).

Friday 28.04.2017

Prof. Karl Heinz Hoffmann from the Technische Universität Chemnitz, Germany:

"Twin polymerization: reactive molecular dynamics and other approaches"

Note: this seminar will be held at 10:00 !

Friday 28.04.2017

Prof. Karl Heinz Hoffmann from the Technische Universität Chemnitz, Germany:

"Twin polymerization: reactive molecular dynamics and other approaches"

Note: this seminar will be held at 10:00 !

TWIN POLYMERiZATION: Reactive Molecular Dynamics and other approaches

Karl Heinz Hoffmann1

1 Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz, Germany,

e-mail: hoffmann@physik.tu-chemnitz.de

 

Polymer hybrid materials, i.e. materials combining organic polymer structures with inorganic components on the nanoscale, play an important role in reinforcing, coating and barrier materials. The production of such nanostructured polymer hybrid materials is a challenging task, since two different components must be merged together, while suppressing phase separation processes on the molecular level.

In recent years a more elegant technique called twin polymerization [1] has been developed to synthesize these hybrid materials with organic and inorganic structure domains. Twin polymerization is a special process that utilizes twin monomers containing differently polymerizable groups in one molecule, where only one initialization step is necessary to start the process.

The theoretical understanding of the overall twin polymerization process and especially of the structure formation of the composite material is still at the beginning. After introducing the basic concepts of twin polymerization, different modeling approaches for the complex reaction mechanism of twin polymerization will be shown. The utilized methods include reactive molecular dynamics simulation [3] and reactive Bond-Fluctuation-Models (rBFM).

Thursday 17.03.2017

Tommaso D'Agostino from Universita di Cagliari :

"Multiscale MD approaches and their applications in the study of molecular translocation in bacteria"

Thursday 17.03.2017

Tommaso D'Agostino from Universita di Cagliari :

"Multiscale MD approaches and their applications in the study of molecular translocation in bacteria"

DSF-Universita di Cagliari

Thursday 16.03.2017

Thursday 16.03.2017

Abstract
Parabens (p-hydroxybenzoic acid esters), bisphenols, benzophenone-type UV filters, triclosan, and triclocarban are used in a variety of consumer products, including baby teethers. Nevertheless, the exposure of infants to these chemicals through the use of teethers is still unknown. In this study, 59 teethers, encompassing three types, namely solid plastic, gel-filled, and water-filled (most labeled " bisphenol A-free "), were collected from the U.S. market and analyzed for 26 potential endocrine-disrupting chemicals (EDCs) from intact surfaces through migration/leaching tests performed with Milli-Q water and methanol. The total amount of the sum of six parent parabens (Σ 6 Parabens) leached from teethers ranged from 2.0 to 1990 ng, whereas that of their four transformation products (Σ 4 Parabens) ranged from 0.47 to 839 ng. The total amount of the sum of nine bisphenols (Σ 9 bisphenols) and 5 benzophenones (Σ 5 benzophenones) leached from teethers ranged from 1.93 to 213 ng and 0.59 to 297 ng, respectively. Triclosan and triclocarban were found in the extracts of teethers at approximately 10-fold less amounts than were bisphenols and benzophenones. Based on the amount leached into Milli-Q water, daily intake of these chemicals was estimated from the use of teethers by infants at 12 months of age. This is the first study to document the occurrence and migration of a wide range EDCs from intact surfaces of baby teethers.

Thursday 02.03.2017

Vishwesh Venkatraman and Sigvart Evjen : "Ionic liquids for CO2 Capture".

Thursday 02.03.2017

Vishwesh Venkatraman and Sigvart Evjen : "Ionic liquids for CO2 Capture".

Multi-speaker seminar

Monday 27.02.2017

Prof. Youhei Fujitani from Keio University, Yokohama: "Fluctuation amplitude of an externally trapped rigid sphere in a near-critical binary fluid mixture within the regime of the Gaussian model".(arXiv:1510.03512 condmat.soft)
 

Monday 27.02.2017

Prof. Youhei Fujitani from Keio University, Yokohama: "Fluctuation amplitude of an externally trapped rigid sphere in a near-critical binary fluid mixture within the regime of the Gaussian model".(arXiv:1510.03512 condmat.soft)
 

Abstract
The position of a colloidal particle trapped in an external field thermally fluctuates at the equilibrium. As is well known, the ambient fluid is not a simple heat bath and a moving particle appears heavier, which influences the mean square velocity of the particle. When the ambient fluid is a near-critical binary fluid mixture, the profile of the concentration difference does not follow the particle motion totally, which is expected to influence the mean square displacement of the particle. We calculate the influence in a simple case, where a rigid sphere fluctuates with small amplitude, the mixture in the homogeneous phase is near, but not very close to, the critical point, and the particle surface attracts one component weakly. What we calculate is an equal-time correlation, but we utilize the hydrodynamics in the limit of no dissipation to examine the contribution from the ambient fluid. According to our result, the mean square displacement is reduced by the additional stress, including the osmotic pressure, due to the ambient near-criticality combined with the preferential attraction.

Thursday 16.02.2017

Dr. Mathias Winkler from the physics department:

"Weakly-bound Clusters studied by theory-assisted X-ray Photoelectron Spectroscopy"

Thursday 16.02.2017

Dr. Mathias Winkler from the physics department:

"Weakly-bound Clusters studied by theory-assisted X-ray Photoelectron Spectroscopy"

Department of physics and applied theoretical chemistry.

Thursday 26.01.2017

Prof. Antonio Rizzo from Istituto per processi chimico-fisici (Pisa) :

"Electronic (mainly chiral) nonlinear spectroscopies: recent contributions of theory and computational science".

Thursday 26.01.2017

Prof. Antonio Rizzo from Istituto per processi chimico-fisici (Pisa) :

"Electronic (mainly chiral) nonlinear spectroscopies: recent contributions of theory and computational science".

Antonio Rizzo is a theoretical and computation chemist, his main research interests concern structural and response properties of atomic and molecular systems under intense laser pulses (http://h2.pi.ipcf.cnr.it/rizzo/ar.html). He is a senior research at the "Istituto per processi chimico-fisici" of the CNR (Consiglio nazionale delle ricerche) in Pisa.

Thursday 12.01.17

Dr. Anders Lervik

"Modelling of Alginate C-5 Epimerases"

Thursday 12.01.17

Dr. Anders Lervik

"Modelling of Alginate C-5 Epimerases"

QuantiTis group !

Friday 16.12.2016 at 14.15

Dr. Fathollah Varnik, Ruhr-Universität Bochum, Germany.

"Lattice Boltzmann modelling of multiphase flows and its application to micro- and nanofluidics"

Friday 16.12.2016 at 14.15

Dr. Fathollah Varnik, Ruhr-Universität Bochum, Germany.

"Lattice Boltzmann modelling of multiphase flows and its application to micro- and nanofluidics"

In the past 25 years, the lattice Boltzmann method has evolved to a versatile and computationally powerful numerical tool to study various physical phenomena in fluids. In this talk, a short introduction to the basic foundations of the method shall be given. The method is then used to address interesting, still not fully resolved, fundamental problems such as the coalescence dynamics of two identical drops in the viscous dominated regime and the spreading of drops at the nanoscale, where thermal fluctuations play a major role for the spreading kinetics.

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