There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

How has Japan become a major economic power, a world leader in the automotive and electronics industries? What is the secret of their success? The consensus has been that, though the Japanese are not particularly innovative, they are exceptionally skilful at imitation, at improving products that already exist. But now two leading Japanese business experts, Ikujiro Nonaka and Hiro Takeuchi, turn this conventional wisdom on its head: Japanese firms are successful, they contend, precisely because they are innovative, because they create new knowledge and use it to produce successful products and technologies. Examining case studies drawn from such firms as Honda, Canon, Matsushita, NEC, 3M, GE, and the U.S. Marines, this book reveals how Japanese companies translate tacit to explicit knowledge and use it to produce new processes, products, and services.

The knowledge-creating company : how Japanese companies create the dynamics of innovation

Accelerating the discovery of advanced materials is essential for human welfare and sustainable, clean energy. In this paper, we introduce the Materials Project (www.materialsproject.org), a core program of the Materials Genome Initiative that uses high-throughput computing to uncover the properties of all known inorganic materials. This open dataset can be accessed through multiple channels for both interactive exploration and data mining. The Materials Project also seeks to create open-source platforms for developing robust, sophisticated materials analyses. Future efforts will enable users to perform ‘‘rapid-prototyping’’ of new materials in silico, and provide researchers with new avenues for cost-effective, data-driven materials design. © 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

/pdf/commentary-the-materials-project-a-materials-genome-approach-3kpccfz11d.pdf

Commentary: The Materials Project: A materials genome approach to accelerating materials innovation

This study, utilizing high-fidelity methods for computing electron-phonon scattering rates, theoretically demonstrates that ultrahigh intrinsic bulk thermoelectric performance across cryogenic-to-high temperatures is physically possible. It also demonstrates the benefit of accidental band degeneracy to thermoelectric performance is conditional upon their characters. Full-Heusler Sr$_{2}$BiAu featuring ten energy-aligned dispersive pockets (six along $\Gamma-X$ and four at $L$) is herein predicted to be theoretically capable of delivering $zT=0.4-4.9$ at $100-700$ K. Relative to the previously investigated Ba$_{2}$BiAu, the additional $L$-pockets in Sr$_{2}$BiAu significantly increase the power factor at low temperatures, as high as 12 mW m$^{-1}$ K$^{-2}$ near room temperature. As temperature rises, the performance decays quickly and sinks below that of Ba$_{2}$BiAu due to the differing dispersion and scattering characteristics of the $L$ and $\Gamma-X$ states. Sr$_{2}$SbAu is generally projected to deliver worse performance due to the appreciable energy-misalignment in the two accessible band pockets. The dominant intrinsic defect at play is Bi/Sb$_{\text{Au}}$ antisites, which limit the $n$-dopabilities of all of the Heusler compounds. Calculations suggest only Sr$_{2}$SbAu potentially has both a large enough stability region and high enough Sb$_{\text{Au}}$ antisite formation energies to retain some small chance at experimental realization as a high-performing thermoelectric.

High Thermoelectric Performance in Multi-pocketed Full-Heuslers and Their Defect Energetics

http://ma.ecsdl.org/content/MA2010-03/1/466.full.pdf

A Novel Carbophosphate Compound as Cathode Material for Lithium-Ion Batteries

This study compared module power loss for 36 modules that endured various accelerated aging test sequences before installation outdoors on a 10-kWp array in Birmingham, AL, USA for 1.72 to 2.72 years. Twelve modules endured standard IEC 61215 aging tests and 24 endured Qualification Plus (Qual Plus). Modules in each group were further split into two test sequences with different exposures. Electrical parameter variations were analyzed as a function of aging test and field exposure history. Fill factor loss was determined to be the cause of observed decreases in power output during accelerated aging tests, while decreases in both open circuit voltage and fill factor dominated the power loss during subsequent on-sun testing. Quantified cell crack features were extracted via computer vision tools from electroluminescence images and correlated with power loss. Results illustrate that standard aging tests led to negligible cracks, while Qual Plus test sequences yielded more severe cracks. While correlating results from qualification tests with in-field performance degradation parameters remains a challenge, this study provides new insights on specific environmental stressors and crack features that may play a role in power loss. Insights on accelerated aging protocols are discussed.

Analysis of PV Module Power Loss and Cell Crack Effects Due to Accelerated Aging Tests and Field Exposure

Studies with stannous hexacyanoferrate(III) epoxy resin based lead selected membranes

The present invention generally relates to carbophosphates and other compounds Such compounds may be used in batteries and other electrochemical devices, or in other applications such as those described herein One aspect of the invention is generally directed to carbophosphate compounds, ie, compounds containing carbonate and phosphate ions For example, according to one set of embodiments, the compound has a formula A x (M)(PO 4 ) a (CO 3 ) b , where M comprises one or more cations A may include one or more alkali metals, for example, lithium and/or sodium In some cases, x is greater than about 01, a is between about 01 and about 51, and b is between about 01 and about 51 In certain embodiments, the compound may have a unit cell atomic arrangement that is isostructural to unit cells of the minerals sidorenkite, bonshtedtite, bradleyite, crawfordite, or ferrotychite In some embodiments, the compound may have a formula A x (M)(YO 4 ) a (XO 3 ) b , where A comprises one or more alkali metals, M comprises one or more cations, X includes B, C, and/or N, and Y includes Si, P, As, S, V, Nb, Mo, and/or W In some cases, x is greater than about 01, a is between about 01 and about 51, and b is between about 01 and about 51 Other aspects of the invention are generally directed to techniques for making or using such compounds, kits involving such compounds, and the like

Anubhav Jain

Papers

High Thermoelectric Performance in Multi-pocketed Full-Heuslers and Their Defect Energetics

A Novel Carbophosphate Compound as Cathode Material for Lithium-Ion Batteries

Analysis of PV Module Power Loss and Cell Crack Effects Due to Accelerated Aging Tests and Field Exposure

Studies with stannous hexacyanoferrate(III) epoxy resin based lead selected membranes

Carbophosphates and related compounds