July 2016 - Allocations-admins - mailman3.cels.anl.gov

[LCRC Accounts] Project Request: chargetransport
by accounts＠lcrc.anl.gov 20 Jul '16

20 Jul '16

Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Marton Voros Applicant's institution: ANL Applicant's division: MSD Project Name: chargetransport Project title: Charge transport in energy materials from first principles Associated funding: LDRD -- Charge Transport in Nanostructured Materials from ab initio Simulations Other Systems: NERSC, 200.000 hours Science: The ultimate goal of this project is to understand and engineer charge transfer processes in materials relevant for energy storage and conversion. In the immediate future, we will be looking at disproportionation in Lithium Manganese Oxide (LMO) batteries. It is known that disproportionation is a detrimental process but the atomistic reasons leading to it are yet unknown. Since disproportionation can be imagined as a charge transfer process, our computational program may reveal the atomistic reasons behind disproportionation and help propose strategies to eliminate it. Having understood this process in bulk and slab models of LMO, we will turn towards other oxide materials and we will also look at charge transport across interfaces. Project description: We will be using first principles methods based on density functional theory. In particular, for simulating oxide cathode materials we are planning to use the plane wave code Quantum Espresso (QE). QE can make use of efficient linear algebra (Lapack, BLAS, Scalapack, BLACS) and FFT libraries, if they are available. QE was shown to efficiently scale to a few hundreds of processors in the case of non-hybrid functional calculations. Hybrid functional calculations can scale up to a few thousands of cores. We will plan to use 80% of our allocation on non-hybrid functional calculations and we will use the remaining 20% of the time to do more expensive (but also more accurate) hybrid functional calculations on selected systems. A typical non-hybrid functional calculation will take several hours of wall clock time (up to tens of hours) on a few hundred processors. There is an efficient restart mechanism in QE allowing use to run smaller jobs. This is useful if the wall-clock time limit does not allow to finish big calculations in one step. To simulate charge transfer processes, we will first identify sites that localize charges in the form of polaron-like carriers. Then, we will use nudged-elastic band and Marcus-theory-like methods to simulate charge transfer between the sites. We will also use cluster models to simulate excited state charge transfer processes. Our preliminary tests showed that NWChem is the best suited code at present to simulate charge transfer in the excited state. NWChem was also shown to scale efficiently to a few hundreds of processors. Industry partnership: Project URL: Requested allocation: 450000 Q1: 0 Q2: 0 Q3: 0 Q4: 450000 Justification: Storage requirements: 2 TB. We will need to, at least temporarily, save wave functions and charge densities to enable efficient restarts of QE calculations. Since these quantities are saved on grids and can be several tens of GBs in size, we estimate we will need about 2 TB of storage. The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Request: copolymer_dsa
by accounts＠lcrc.anl.gov 19 Jul '16

19 Jul '16

Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Abelardo Ramirez-Hernandez Applicant's institution: ANL Applicant's division: MSD Project Name: copolymer_dsa Project title: Directed Self-Assembly of Block Copolymers Associated funding: Other Systems: Science: The morphology of a block copolymer thin film is particularly sensitive to its boundary conditions. Lithographic applications of block polymers in the microelectronics and memory device industries require formation of particular complex morphologies. Current fabrication targets envisage the creation of dense arrays of structures with domain sizes in the sub-10 nm regime. In this project, a coarse grained approach will be used to perform a systematic study of a wide range of polymeric material combinations and conditions, leading to optimal assembly. We will consider the effect of molecular weight, block copolymer film thickness and chain architecture, and degree of incompatibility, etc. Our results will be summarized in the form of generic phase diagrams that should serve as a guide for experiments. Project description: Our efforts in this project will be focused on the self-assembly of block copolymer thin films directed by patterned surfaces. Given the relatively large number of parameters involved, a combinatorial search of optimal conditions is necessary. Multiple simulations will be bundled together as ensemble jobs using a coarse grained simulation approach. Ensemble runs performing parameter sweep (chain architecture, polymer-substrate interactions, etc.) will be structured as 24-hour ensemble runs. Industry partnership: Brewer Science Project URL: Requested allocation: 96000 Q1: 0 Q2: 0 Q3: 0 Q4: 96000 Justification: Storage requirements: 1TB The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Allocation Request
by accounts＠lcrc.anl.gov 18 Jul '16

18 Jul '16

Hello, A change in allocation has been requested: Requester: qiaobf (Baofu Qiao) Project: DMDOHEMA_1 Title: Metal Ion Transport through Nano-Structured Lipophilic Systems: Atomistic MD Simulations Description: In the last few months, we have performed some preliminary simulation runs in understanding the supra-molecular aggregate structure in organic phases under the project DMDOHEMA_1 on LCRC. Some findings have been unveiled, e.g., the presences of water, acid, Eu(NO3)3 all affect the supra-molecular aggregate structure of extractant (i.e., DMDOHEMA) in organic phased. These findings agree with the existing experimental data. However, due to the small size of those simulation systems, the aggregation behaviors are not converged well. Therefore, in the renewal period of project DMDOHEMA_1, we are aiming to enlarge our simulation boxes so that such findings can be solidified. Moreover, one already finished large simulation supports that larger simulation box decreases the calculated error bar of the aggregation number of DMDOHEMA. With the simulations on large enough simulation boxes, the effects of water, acid, Eu(NO3)3 will be distinguished, which will surely provi de significant insight for the rational design of higher efficient extractants. Our project is expected to highly spark the development of rare earth element related technologies. In this project, classical molecular dynamics (MD) simulations will be performed at the all-atom resolution, in addition to the concurrent solvent extraction experiments at ANL. All-atom MD simulations have been well proven in predicting supra-molecular aggregate structures. The open source package GROMACS will be employed for the simulations. GROMACS is one of the highly recommended packages for MD simulations. GROMACS has been reported to be able to scale well up to around 1,000 CPU processors. Based on our experience on LCRC, the simulations can be LINEARLY scaled up to 256 CPU cores, under which condition the simulation speed is around 3 hours/ns for a system of the size of around 17 × 17 × 17 = 5000 nm3. Two users will use this allocation time, Dr. Ross J. Ellis and Dr. Baofu Qiao, both at the CSE division at ANL. In the first phase of this project, we are studying the influence of a variety of components, i.e., water, acid, Eu(NO3)3, on the aggregate structures of DMDOHEMA extractants dissolved in n-heptane organic phases. As aforementioned, this project is currently ongoing. With the allocation from LCRC, we are able to collects some conclusions in the near fure. In the second phase, we plan to study the effect of extractant on the supra-molecula aggregate structure. The extraction of DMDBTDMA, which is the preceding extractant of DMDOHEMA, will be simulated and compared with the simulation results of DMDOHEMA systems. According to the available experimental data, the effects of some factors will be explore, such as the concentration of water, the concentration of Eu(NO3)3 complexes, the concentration of acidic molecule of HNO3. Current: undetermined amount Justification: Table. Benchmark of the simulation speed on LCRC #CPU cores 16 32 64 256 Speed (ns/day) 0.51 1.0 2.0 7.7 Based on the benchmark simulations, we can conclude that the scaling on LCRC can be linearly up to at least 256 CPU cores for our simulations. Requested: 200000 A specific reason has been given: Dear Sir/Madam, My allocation is running out. I need more allocation for my ongoing simulations. Thanks a lot for your kind help! regards, Baofu This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Allocation Request
by accounts＠lcrc.anl.gov 18 Jul '16

18 Jul '16

Hello, A change in allocation has been requested: Requester: ango (Anh Ngo) Project: ReNiO3 Title: Structural Evolution of rare earth nickelates under high pressure conditions Description: Structure optimizations of ReNiO3 (~80 atoms) with different magnetic configurations will be carried out using (2 x 1x 2) bulk unit cells. By comparing different magnetic ordering energies we will conclude which configuration corresponding to the ground state energy. Once ground state structure is found we will go on to address the structural dependence of ReNiO3 under high pressure. We intend to carry out the density functional theory (DFT) calculations using the VASP package. Periodic boundary condition (PBC) will be imposed in order to maintain periodicity of the solid support. Gradient corrected PBE density functional will be used for these calculations. Those programs are currently available on Blues cluster and scale reasonably well on parallel processors. Energy optimization of ReNiO3 (~80 atoms contain 16 Ni with different spin configurations) using GGA+U takes approximately 4608 CPU hours (16*6*48) and we plan roughly 60 of such calculations. For pressure calculations, since ReNiO3 is a correlated complex oxide, we will perform density functional theory (DFT) calculations using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional and performed the atomic relaxations within the unit cells. This takes roughly 4608 CPU hours (16*6*48) and we plan to run 80 of these calculations. To investigate metal-insulator transition we plan to run additional 66 HSE calculations for the density of state (DOS) at the ambient pressures of 0 GPa to 3.4 GPa. So our total request is 60*4608 + (80+66)* 4608 =949248 core hours. Current: undetermined amount Justification: VASP package is widely used on Blues and its scaling is well documented. Requested: 150000 A specific reason has been given: We need more allocation for this project. Thanks, Anh Ngo and Peter Zapol This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Allocation Request
by accounts＠lcrc.anl.gov 18 Jul '16

18 Jul '16

Hello, A change in allocation has been requested: Requester: ango (Anh Ngo) Project: ReNiO3 Title: Structural Evolution of rare earth nickelates under high pressure conditions Description: Structure optimizations of ReNiO3 (~80 atoms) with different magnetic configurations will be carried out using (2 x 1x 2) bulk unit cells. By comparing different magnetic ordering energies we will conclude which configuration corresponding to the ground state energy. Once ground state structure is found we will go on to address the structural dependence of ReNiO3 under high pressure. We intend to carry out the density functional theory (DFT) calculations using the VASP package. Periodic boundary condition (PBC) will be imposed in order to maintain periodicity of the solid support. Gradient corrected PBE density functional will be used for these calculations. Those programs are currently available on Blues cluster and scale reasonably well on parallel processors. Energy optimization of ReNiO3 (~80 atoms contain 16 Ni with different spin configurations) using GGA+U takes approximately 4608 CPU hours (16*6*48) and we plan roughly 60 of such calculations. For pressure calculations, since ReNiO3 is a correlated complex oxide, we will perform density functional theory (DFT) calculations using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional and performed the atomic relaxations within the unit cells. This takes roughly 4608 CPU hours (16*6*48) and we plan to run 80 of these calculations. To investigate metal-insulator transition we plan to run additional 66 HSE calculations for the density of state (DOS) at the ambient pressures of 0 GPa to 3.4 GPa. So our total request is 60*4608 + (80+66)* 4608 =949248 core hours. Current: undetermined amount Justification: VASP package is widely used on Blues and its scaling is well documented. Requested: 150000 A specific reason has been given: We need more allocation for this project. Thanks, Anh Ngo and Peter Zapol This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Allocation Request
by accounts＠lcrc.anl.gov 18 Jul '16

18 Jul '16

Hello, A change in allocation has been requested: Requester: ango (Anh Ngo) Project: AlN Title: A DFT study of reaction pathways of NH3 decomposition on AlN (0001) surface Description: Previously, we have performed structure optimizations of the adsorbate-free (0001) surface of AlN and determined reaction pathways for NH3 decomposition using (2 × 2) surface unit cells. Next, we will perform density functional theory (DFT) calculations to determine structure, bonding, and reaction energies of the Al adsorbed species. We will also extend our calculations to other surface orientations, including stepped surfaces. Periodic boundary condition (PBC) will be imposed in order to maintain periodicity of the solid support. Gradient corrected PBE density functional will be used for these calculations. The Climbing Nudged Elastic Band (cNEB) method of Henkelman and coworkers will be used to calculate transition states and activation barriers for formation of different surface species. Each structure in the supported (0001) surface of AlN typically involves ~100 atoms. To obtain accurate reaction energies and barriers, rigorous density functional theory (DFT) calculations are needed. We intend to carry out the DFT calculations using the VASP package. VASP is currently available on Blues cluster and scaling with number of processors is well established. For the MPI version of VASP with the system size of ~100 atoms, a good performance was observed up to 32 processors. Energy optimization in VASP takes approximately 1000 CPU hours and we plan approximately 200 of such calculations for different adsorbate geometries for each of 3 surface orientations. The Climbing Nudged Elastic Band (cNEB) calculation (with 5 to 7 images) takes approximately 3000 CPU hours and we plan to run 60 of these calculations to find reaction pathways. So our total request is 1000*200*3 + 60*3000 = 850,000 core hours Current: undetermined amount Justification: VASP performance on Blues is well established, we use the latest version maintained on Blues. Requested: 200000 A specific reason has been given: We need more allocation for this project. Thanks This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System

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[LCRC Accounts] Project Allocation Request
by accounts＠lcrc.anl.gov 18 Jul '16

18 Jul '16

Hello, A change in allocation has been requested: Requester: ango (Anh Ngo) Project: AlN Title: A DFT study of reaction pathways of NH3 decomposition on AlN (0001) surface Description: Previously, we have performed structure optimizations of the adsorbate-free (0001) surface of AlN and determined reaction pathways for NH3 decomposition using (2 × 2) surface unit cells. Next, we will perform density functional theory (DFT) calculations to determine structure, bonding, and reaction energies of the Al adsorbed species. We will also extend our calculations to other surface orientations, including stepped surfaces. Periodic boundary condition (PBC) will be imposed in order to maintain periodicity of the solid support. Gradient corrected PBE density functional will be used for these calculations. The Climbing Nudged Elastic Band (cNEB) method of Henkelman and coworkers will be used to calculate transition states and activation barriers for formation of different surface species. Each structure in the supported (0001) surface of AlN typically involves ~100 atoms. To obtain accurate reaction energies and barriers, rigorous density functional theory (DFT) calculations are needed. We intend to carry out the DFT calculations using the VASP package. VASP is currently available on Blues cluster and scaling with number of processors is well established. For the MPI version of VASP with the system size of ~100 atoms, a good performance was observed up to 32 processors. Energy optimization in VASP takes approximately 1000 CPU hours and we plan approximately 200 of such calculations for different adsorbate geometries for each of 3 surface orientations. The Climbing Nudged Elastic Band (cNEB) calculation (with 5 to 7 images) takes approximately 3000 CPU hours and we plan to run 60 of these calculations to find reaction pathways. So our total request is 1000*200*3 + 60*3000 = 850,000 core hours Current: undetermined amount Justification: VASP performance on Blues is well established, we use the latest version maintained on Blues. Requested: 200000 A specific reason has been given: We need more allocation for this project. Thanks This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System

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Re: [allocations-admins] [LCRC Accounts] Project Allocation Request
by John Blaas 13 Jul '16

13 Jul '16

Granted 50k to Redoxshuttles JB On Wed, Jul 13, 2016 at 10:01 AM, Bair, Raymond A. <rbair(a)anl.gov> wrote: > Lets approve this 50K request. > > Ray > > > ----------------------------------------- > Ray Bair > Argonne National Laboratory > > > On 7/12/16, 5:06 PM, "allocations-admins-bounces(a)lcrc.anl.gov on behalf of accounts(a)lcrc.anl.gov" <allocations-admins-bounces(a)lcrc.anl.gov on behalf of accounts(a)lcrc.anl.gov> wrote: > > Hello, > > A change in allocation has been requested: > > Requester: redfern (Paul Redfern) > Project: Redoxshuttles > Title: Redox Shuttles and Additives for Lithium-Ion Batteries > Description: Over the past year we have calculated solvation free energies of molecular LiO2 and Li2O2 in various solvents were calculated using various explicit and implicit solvent models, as well as ab initio molecular dynamics (AIMD) methods. Best estimates for the solvation energies from these calculations along with calculated lattice energies of Li2O2 and LiO2 were used to determine the solubility of bulk LiO2 and Li2O2. The solubility of LiO2 was found to be about 17 orders higher than that of Li2O2. The effect of finite crystal size of LiO2 and Li2O2 on the solubility was also considered and was found to increase the solubility, although LiO2 is still much more soluble. The difference in solubilities between LiO2 and Li2O2 will likely affect the growth mechanism and resulting morphologies of the products formed during battery discharge, affecting the performance of the battery cell. We also examined production of a lithium superoxide discharge product on the cathod > e in a Li-O2 battery. DFT was used to obtain values of material properties not available experimentally such as LiO2 solubility in DME and elastic properties of the particles. The mesoscale model predicts that coarsening, in which large particles grow and small ones disappear, has a substantial effect on the size distribution of the LiO2 particles during the discharge process. The size evolution during discharge is the result of an interplay between this coarsening process as well as growth. The growth through continued deposition of LiO2 has the effect of causing large particles to grow faster and delays the dissolution of small particles. The predicted size evolution is consistent with experimental results for a previously reported cathode material based on activated carbon during discharge and when it is at rest. The model, even without complex microstructure, can capture size and number of LiO2 particles, but not the shape, e.g. toroid formation. Best estimates for the L > iO2 solvation energy from these calculations along with a calculated lattice energy of LiO2 were used to determine the solubility of bulk LiO2. The best estimate for the solubility of LiO2 is about 1 mM, although this has very large uncertainties because small differences in the calculated solvation energy leads to large differences in the solubility due to the exponential. For example, a difference of 2 kcal/mol in solvation energy translates to more than 2 orders of magnitude difference in solubility. The solvation energies are difficult to calculate even to 2 kcal/mol in accuracy. This value from density functional calculations is used initially in the model and subsequently a value for solubility is derived from fits to reproduce experimental data. The solubility from these fits is similar to that predicted from the DFT calculations. > > We intend to evaluate at least 200 electrolytes for Lithium-O2 batteries. The most important challenge in Lithium-Air battery research is finding stable non-aqueous electrolytes which permit reversible cycling of the cell. A solvent should have a high dielectric constant in order to dissolve Li+, low viscosity for fast Li+ transport, high stability, low vapor pressure, high oxygen solubility, high O2 and superoxide transport properties, and low toxicity. Solvents should partially dissolve lithium oxide species in order to reduce clogging and increase charge current rate. Quantum chemical calculations can help identify reaction pathways which affect reversibility. So far organic solvents such as ethers, amides, lactams, oxazolidinones, phosphorus compounds and nitriles have been screened for Lithium-Air batteries based on susceptibility to attack by superoxide anion and pKa. No correlation between simple molecular descriptors and activation free energies was found. Low electro > philicity has also been used to identify potential candidates, since they would be less susceptible to attack by superoxide or other anion. Other solvents such as sulfones, sulfoxides and ionic liquids have been examined. Lithium salts like LiTFSI can decompose at the lithium electrode and the resulting CF3 radicals can abstract hydrogens from solvents like ethers. Hydrogens on carbons adjacent to heteroatoms (e.g. O, N, F) are more labile due to the anomeric effect. Superoxide anion can abstract protons from proton source impurities (e.g. water) leading to formation of the strong base HOO- via disproportionation which can then react as a nucleophile with the solvent. Superoxide was found not to react with TEGDME ether (Nazar). We will use hydrogen and proton abstraction from and nucleophilic attack by a strong base on the electrolyte along with advanced descriptors (e.g. Fukui functions, hardness and chemical potential) to screen for stable solvents. > > Oxygen reduction in the aprotic Li-O2 battery takes place at the boundary between the electrolyte and the cathode so oxygen must dissolve and diffuse in the electrolyte. Unfortunately, aprotic solvents are inadequate in this regard so oxygen enriching materials must be developed. Oxygen enriching materials that have been examined include cobalt porphyrin, iron phthalocyanine, artificial hemoglobin, membranes and perfluorochemicals (PFCs). PFCs have high oxygen solubility, low surface tension and viscosity to enhance O2 diffusivity and Li+ transference number as well as wettability of the cathode surface, high chemical and thermal stability, hydrophobicity and low flammability. In the Li-O2 battery the PFC must be miscible with the polar organic solvent and resistant to nucleophilic attack by superoxide anion radical or HOO-. Miscibility of PFCs with polar organic solvents is increased if LiPFOS is used instead of LiTFSI. Increasing O2 pressure increases O2 diffusivity as well > as solubility. We will examine many PFCs for susceptibility to nucleophilic attack by superoxide anion radical and HOO- using DFT calculations. Ab initio calculations will also be done to improve our understanding of interactions between PFCs and O2. Other oxygen enriching materials include reversible oxygen carriers like perfluoro cryptands and crown ethers which are known to have high oxygen carrying capacities, while acyclic perfluoro ethers do not bind O2. DFT calculations will be used to examine perfluoro cryptands and crown ethers. Hybrid ionic liquid fluoro-organic solvent mixtures are also promising as they combine the stability to anion attack of ionic liquids with the high oxygen transport and safety of nonflammable fluoro-organics. > We intend to use Gaussian 09 for quantum chemical calculations. In Gaussian 09 the DFT calculations scale well up to 64 processors, however the high-level ab initio methods scale only up to 16 processors. Therefore these calculations do require a longer execution time. > > Current: undetermined amount > Justification: > > Requested: 50000 > > A specific reason has been given: > I am currently in the middle of calculating transition states and reaction energies for the lithium sulfur battery. This will help our understanding of the underlying mechanisms and hasten the development of safer, more energy dense batteries. > > This needs to be approved and the final allocation amount decided upon. > > Thank You, > The LCRC Accounts System > _______________________________________________ > allocations-admins mailing list > allocations-admins(a)lcrc.anl.gov > https://lists.lcrc.anl.gov/mailman/listinfo/allocations-admins > > > _______________________________________________ > allocations-admins mailing list > allocations-admins(a)lcrc.anl.gov > https://lists.lcrc.anl.gov/mailman/listinfo/allocations-admins

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Re: [allocations-admins] [LCRC Accounts] Project Allocation Request
by John Blaas 13 Jul '16

13 Jul '16

Granted 200k to CFD-TPM JB On Tue, Jul 12, 2016 at 2:50 PM, Bair, Raymond A. <rbair(a)anl.gov> wrote: > This request for 200K looks OK. > > Ray > > > ----------------------------------------- > Ray Bair > Argonne National Laboratory > > > On 7/12/16, 2:22 PM, "allocations-admins-bounces(a)lcrc.anl.gov on behalf of accounts(a)lcrc.anl.gov" <allocations-admins-bounces(a)lcrc.anl.gov on behalf of accounts(a)lcrc.anl.gov> wrote: > > Hello, > > A change in allocation has been requested: > > Requester: svegendla (Prasad Vegendla) > Project: CFD-TPM > Title: Computational Fluid Dynamics Modeling of Two-phase Boiling Flow and Critical Heat Flux > Description: In boiling water reactors, dryout is an important limiting phenomenon in the design of heat exchangers and is associated with the disappearance of the liquid film on the wall in heat exchanger tube. A consequence of this non-wetting heated surface deteriorates the convective heat transfer mechanism resulting in a large rise in the wall temperature of heat flux imposed system such as nuclear reactor fuel rod assemblies. Since dryout is a hydrodynamic phenomenon involving entrainment and redeposition of droplets as well as boiling/evaporation of the liquid, the location of dryout is dynamic and its fluctuation may also give rise to thermal fatigue and corrosion. A large number of experimental and theoretical studies have been conducted over the past several decades to understand and quantify the processes leading to dryout in a heat exchanger tube. > > * Nek5000 is a highly-scalable open-source transient CFD code developed by MCS-Argonne National Laboratory. This code is based on spectral element method and it is written in basic FORTRAN and C languages. It has more than 200 users world-wide and a long history of development, verification, and validation. > > * In this project, Nek5000 is used as a platform to develop two-fluid model. > > * In order to validate the Nek5000 development for two-phase boiling capability, several simulation runs are planned for wide range of pressure, mass flux and wall heat flux. > > * In FY2015, blues allocated hours are efficiently used for projects of CFD-TPM, NE_RANS and SHARP-IF. > > * A total of 4 members can use the allocated hours > Current: undetermined amount > Justification: Nek5000 is a highly scalable tool on fusion. NE users demonstrated good scalability up to several hundred cores. Recent simulations of homogeneous two-fluid boiling model on Fusion cores reported 10% and 58% overhead associated with MPI communication for 128 and 256 cores, respectively. > > > Requested: 200000 > > A specific reason has been given: > To validate NEK5000 two-phase boiling code for multiple bench mark tests. > > This needs to be approved and the final allocation amount decided upon. > > Thank You, > The LCRC Accounts System > _______________________________________________ > allocations-admins mailing list > allocations-admins(a)lcrc.anl.gov > https://lists.lcrc.anl.gov/mailman/listinfo/allocations-admins > > > _______________________________________________ > allocations-admins mailing list > allocations-admins(a)lcrc.anl.gov > https://lists.lcrc.anl.gov/mailman/listinfo/allocations-admins

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Re: [allocations-admins] [LCRC Accounts] Project Allocation Request
by Bair, Raymond A. 13 Jul '16

13 Jul '16

Lets approve this 50K request. Ray ----------------------------------------- Ray Bair Argonne National Laboratory On 7/12/16, 5:06 PM, "allocations-admins-bounces(a)lcrc.anl.gov on behalf of accounts(a)lcrc.anl.gov" <allocations-admins-bounces(a)lcrc.anl.gov on behalf of accounts(a)lcrc.anl.gov> wrote: Hello, A change in allocation has been requested: Requester: redfern (Paul Redfern) Project: Redoxshuttles Title: Redox Shuttles and Additives for Lithium-Ion Batteries Description: Over the past year we have calculated solvation free energies of molecular LiO2 and Li2O2 in various solvents were calculated using various explicit and implicit solvent models, as well as ab initio molecular dynamics (AIMD) methods. Best estimates for the solvation energies from these calculations along with calculated lattice energies of Li2O2 and LiO2 were used to determine the solubility of bulk LiO2 and Li2O2. The solubility of LiO2 was found to be about 17 orders higher than that of Li2O2. The effect of finite crystal size of LiO2 and Li2O2 on the solubility was also considered and was found to increase the solubility, although LiO2 is still much more soluble. The difference in solubilities between LiO2 and Li2O2 will likely affect the growth mechanism and resulting morphologies of the products formed during battery discharge, affecting the performance of the battery cell. We also examined production of a lithium superoxide discharge product on the cathod e in a Li-O2 battery. DFT was used to obtain values of material properties not available experimentally such as LiO2 solubility in DME and elastic properties of the particles. The mesoscale model predicts that coarsening, in which large particles grow and small ones disappear, has a substantial effect on the size distribution of the LiO2 particles during the discharge process. The size evolution during discharge is the result of an interplay between this coarsening process as well as growth. The growth through continued deposition of LiO2 has the effect of causing large particles to grow faster and delays the dissolution of small particles. The predicted size evolution is consistent with experimental results for a previously reported cathode material based on activated carbon during discharge and when it is at rest. The model, even without complex microstructure, can capture size and number of LiO2 particles, but not the shape, e.g. toroid formation. Best estimates for the L iO2 solvation energy from these calculations along with a calculated lattice energy of LiO2 were used to determine the solubility of bulk LiO2. The best estimate for the solubility of LiO2 is about 1 mM, although this has very large uncertainties because small differences in the calculated solvation energy leads to large differences in the solubility due to the exponential. For example, a difference of 2 kcal/mol in solvation energy translates to more than 2 orders of magnitude difference in solubility. The solvation energies are difficult to calculate even to 2 kcal/mol in accuracy. This value from density functional calculations is used initially in the model and subsequently a value for solubility is derived from fits to reproduce experimental data. The solubility from these fits is similar to that predicted from the DFT calculations. We intend to evaluate at least 200 electrolytes for Lithium-O2 batteries. The most important challenge in Lithium-Air battery research is finding stable non-aqueous electrolytes which permit reversible cycling of the cell. A solvent should have a high dielectric constant in order to dissolve Li+, low viscosity for fast Li+ transport, high stability, low vapor pressure, high oxygen solubility, high O2 and superoxide transport properties, and low toxicity. Solvents should partially dissolve lithium oxide species in order to reduce clogging and increase charge current rate. Quantum chemical calculations can help identify reaction pathways which affect reversibility. So far organic solvents such as ethers, amides, lactams, oxazolidinones, phosphorus compounds and nitriles have been screened for Lithium-Air batteries based on susceptibility to attack by superoxide anion and pKa. No correlation between simple molecular descriptors and activation free energies was found. Low electro philicity has also been used to identify potential candidates, since they would be less susceptible to attack by superoxide or other anion. Other solvents such as sulfones, sulfoxides and ionic liquids have been examined. Lithium salts like LiTFSI can decompose at the lithium electrode and the resulting CF3 radicals can abstract hydrogens from solvents like ethers. Hydrogens on carbons adjacent to heteroatoms (e.g. O, N, F) are more labile due to the anomeric effect. Superoxide anion can abstract protons from proton source impurities (e.g. water) leading to formation of the strong base HOO- via disproportionation which can then react as a nucleophile with the solvent. Superoxide was found not to react with TEGDME ether (Nazar). We will use hydrogen and proton abstraction from and nucleophilic attack by a strong base on the electrolyte along with advanced descriptors (e.g. Fukui functions, hardness and chemical potential) to screen for stable solvents. Oxygen reduction in the aprotic Li-O2 battery takes place at the boundary between the electrolyte and the cathode so oxygen must dissolve and diffuse in the electrolyte. Unfortunately, aprotic solvents are inadequate in this regard so oxygen enriching materials must be developed. Oxygen enriching materials that have been examined include cobalt porphyrin, iron phthalocyanine, artificial hemoglobin, membranes and perfluorochemicals (PFCs). PFCs have high oxygen solubility, low surface tension and viscosity to enhance O2 diffusivity and Li+ transference number as well as wettability of the cathode surface, high chemical and thermal stability, hydrophobicity and low flammability. In the Li-O2 battery the PFC must be miscible with the polar organic solvent and resistant to nucleophilic attack by superoxide anion radical or HOO-. Miscibility of PFCs with polar organic solvents is increased if LiPFOS is used instead of LiTFSI. Increasing O2 pressure increases O2 diffusivity as well as solubility. We will examine many PFCs for susceptibility to nucleophilic attack by superoxide anion radical and HOO- using DFT calculations. Ab initio calculations will also be done to improve our understanding of interactions between PFCs and O2. Other oxygen enriching materials include reversible oxygen carriers like perfluoro cryptands and crown ethers which are known to have high oxygen carrying capacities, while acyclic perfluoro ethers do not bind O2. DFT calculations will be used to examine perfluoro cryptands and crown ethers. Hybrid ionic liquid fluoro-organic solvent mixtures are also promising as they combine the stability to anion attack of ionic liquids with the high oxygen transport and safety of nonflammable fluoro-organics. We intend to use Gaussian 09 for quantum chemical calculations. In Gaussian 09 the DFT calculations scale well up to 64 processors, however the high-level ab initio methods scale only up to 16 processors. Therefore these calculations do require a longer execution time. Current: undetermined amount Justification: Requested: 50000 A specific reason has been given: I am currently in the middle of calculating transition states and reaction energies for the lithium sulfur battery. This will help our understanding of the underlying mechanisms and hasten the development of safer, more energy dense batteries. This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System _______________________________________________ allocations-admins mailing list allocations-admins(a)lcrc.anl.gov https://lists.lcrc.anl.gov/mailman/listinfo/allocations-admins

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