scholarly journals Nested sampling for materials

2021 ◽  
Vol 94 (8) ◽  
Author(s):  
Livia B. Pártay ◽  
Gábor Csányi ◽  
Noam Bernstein
Keyword(s):  
Materials Science ◽  
Nested Sampling ◽  
Materials Properties ◽  
The Past ◽  
Lennard Jones ◽  
Atomistic Systems ◽  
Canonical Approach ◽  
Phase Systems ◽  
Thermodynamic Variables ◽  
Grand Canonical

Abstract We review the materials science applications of the nested sampling (NS) method, which was originally conceived for calculating the evidence in Bayesian inference. We describe how NS can be adapted to sample the potential energy surface (PES) of atomistic systems, providing a straightforward approximation for the partition function and allowing the evaluation of thermodynamic variables at arbitrary temperatures. After an overview of the basic method, we describe a number of extensions, including using variable cells for constant pressure sampling, the semi-grand-canonical approach for multicomponent systems, parallelizing the algorithm, and visualizing the results. We cover the range of materials applications of NS from the past decade, from exploring the PES of Lennard–Jones clusters to that of multicomponent condensed phase systems. We highlight examples how the information gained via NS promotes the understanding of materials properties through a novel way of visualizing the PES, identifying thermodynamically relevant basins, and calculating the entire pressure–temperature(–composition) phase diagram. Graphic abstract

The Contribution of Intermediate-Voltage, High-Resolution Electron Microscopy In Materials Science: An Appraisal

1990 ◽  
Vol 48 (1) ◽  
pp. 478-479
Author(s):  
John L. Hutchison
Keyword(s):  
High Resolution ◽  
Materials Science ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
The Past ◽  
Resolution Electron ◽  
Extreme Sensitivity ◽  
Electron Microscopes ◽  
New Generation ◽  
Small Metal Particles

Over the past five years or so the development of a new generation of high resolution electron microscopes operating routinely in the 300-400 kilovolt range has produced a dramatic increase in resolution, to around 1.6 Å for “structure resolution” and approaching 1.2 Å for information limits. With a large number of such instruments now in operation it is timely to assess their impact in the various areas of materials science where they are now being used. Are they falling short of the early expectations? Generally, the manufacturers’ claims regarding resolution are being met, but one unexpected factor which has emerged is the extreme sensitivity of these instruments to both floor-borne and acoustic vibrations. Successful measures to counteract these disturbances may require the use of special anti-vibration blocks, or even simple oil-filled dampers together with springs, with heavy curtaining around the microscope room to reduce noise levels. In assessing performance levels, optical diffraction analysis is becoming the accepted method, with rotational averaging useful for obtaining a good measure of information limits. It is worth noting here that microscope alignment becomes very critical for the highest resolution.In attempting an appraisal of the contributions of intermediate voltage HREMs to materials science we will outline a few of the areas where they are most widely used. These include semiconductors, oxides, and small metal particles, in addition to metals and minerals.

SOMOphilic Alkynylation Using Acetylenic Sulfones as Functional Reagents

2021 ◽  
Author(s):  
Danhua Ge ◽  
Xin Wang ◽  
Xue-Qiang Chu
Keyword(s):  
Drug Discovery ◽  
Organic Synthesis ◽  
Materials Science ◽  
Polymer Chemistry ◽  
The Past ◽  
Acetylenic Sulfones

The past decades have witnessed a boom in alkynylation mainly owing to the importance of alkynyl-containing molecules in organic synthesis, drug discovery, polymer chemistry, and materials science. Besides conventional strategies,...

scholarly journals Database thinking and deep description: designing a digital archive of the National Synchrotron Light Source

2019 ◽  
Vol 34 (Supplement_1) ◽  
pp. i46-i57
Author(s):  
Robert Crease ◽  
Elyse Graham ◽  
Jamie Folsom
Keyword(s):  
Phase Transition ◽  
Large Scale ◽  
Materials Science ◽  
Digital Tools ◽  
Digital Archive ◽  
Big Science ◽  
National Synchrotron Light Source ◽  
The Past ◽  
The Usa ◽  
Synchrotron Light

Abstract Over the past few years, research carried out at large-scale materials science facilities in the USA and elsewhere has undergone a phase transition that affected its character and culture. Research cultures at these facilities now resemble ecosystems, comprising of complex and evolving interactions between individuals, institutions, and the overall research environment. The outcome of this phase transition, which has been gradual and building since the 1980s, is known as the New (or Ecologic) Big Science [Crease, R. and Westfall, C. (2016). The new big science. Physics Today, 69: 30–6]. In this article, we describe this phase transition, review the practical challenges that it poses for historians, review some potential digital tools that might respond to these challenges, and then assess the theoretical implications posed by “database history’.

High-Qe Photodetector for Laser Confocal

1998 ◽  
Vol 4 (S2) ◽  
pp. 418-419
Author(s):  
J. Pawley ◽  
M. Blouke ◽  
J. Janesick
Keyword(s):  
Laser Power ◽  
Materials Science ◽  
Confocal Microscope ◽  
Data Rate ◽  
Research Tool ◽  
Biological Applications ◽  
Fluorescent Marker ◽  
The Past ◽  
Optical Photon ◽  
Laser Confocal Microscope

The laser confocal microscope (LCM) is now an established research tool in biology and materials science. In biological applications, it is usually employed to detect the location of fluorescent marker molecules and, under these conditions, detected signal levels from bright areas often represent <20 photons/pixel (assuming a standard 1.6 μs pixel time) while those from dark areas are likely to average <1 photon/pixel. Although this data rate limits the speed at which information can be derived from the specimen, saturation of the fluorophor, photobleaching of the dye, and phototoxicity often prevent it being increased by simply using more laser power. Over the past 10 years, the optical photon efficiency of commercial confocal instruments has improved significantly and it is now reaching the point where further improvement is becoming very expensive. The only component is which a significant improvement is still possible is the photodetector.

Plutonium in Crystalline Ceramics and Glasses

MRS Bulletin ◽  
2001 ◽  
Vol 26 (9) ◽  
pp. 698-706 ◽  
Author(s):  
Isabelle Muller ◽  
William J. Weber
Keyword(s):  
Long Range ◽  
Nuclear Waste ◽  
Materials Science ◽  
Ceramic Matrix ◽  
Range Order ◽  
Long Range Order ◽  
Geologic Time ◽  
The Past ◽  
Geologic Time Scale ◽  
High Flexibility

The investigation of plutonium in glasses (amorphous ceramics lacking long-range order), in crystalline ceramics, and in composite materials composed of multiple crystalline or glass and crystalline phases, relieson multidisciplinary studies of physics, chemistry, and materials science. It involves the study of the plutonium atoms in materials with only short-range periodicity, as in glasses, to materials with long-range periodicity, as in crystals. The materials studied over the past 30 years include simple binary crystals, used to investigate the electronic structure of plutonium, to complex glasses and ceramics selected not only for the safety and durability that they provide for the immobilization of nuclear waste and plutonium, but also for the high flexibility they offer in composition. The lack of long-range order at the atomic level in glasses permits the inclusion of abroad range of waste elements, but it renders more difficult the interpretation of data from many commonly used experimental techniques. Regardless of the challenge, much of the research conducted in this field over the past few decades has been motivated by the use of plutonium as a surrogate for all nuclear-waste actinides or on its own in immobilization studies, in order to develop a durable glass or ceramic matrix that can resist leaching and mobilization of the plutonium on a geologic time scale.

Materials Education—A Renewal

MRS Bulletin ◽  
1987 ◽  
Vol 12 (4) ◽  
pp. 20-23 ◽  
Author(s):  
G.L. Liedl
Keyword(s):  
Materials Science ◽  
Consumer Products ◽  
Dominant Factor ◽  
Central Position ◽  
National Academy Of Sciences ◽  
Science And Engineering ◽  
The Past ◽  
Materials Science And Engineering ◽  
National Economies ◽  
Academy Of Sciences

Materials have always been interwoven throughout the very fabric of man's history. The present reawakening to the value and importance of materials, however, has become a dominant factor in manufacturing, national security, international competition and trade, consumer products (quality and reliability), and even education. Other renewals of interest have occurred over the centuries, probably beginning with the formation of the first pot from clay. These renewals were associated with discoveries such as copper, iron, and the transistor. However, in the past 40 years the base for renewed interest has broadened.A true coupling of science and engineering into the field of materials was probably initiated in the 1940s and 1950s. Emphasis at that time was on metals and the “new” semiconductors, with an interest that incubated and grew to where their central position in national economies and man's daily life was recognized. In 1970 the National Academy of Sciences appointed a committee to conduct a comprehensive analysis and assessment of the field of “materials science and engineering.” The COSMAT report which resulted from that study had a dramatic impact on the field and has been a frame of reference for the past 17 years. These years have seen a virtual explosion of ideas, processes, and materials in the field.

Defect reactions and clustering in irradiated solids

1990 ◽  
Vol 68 (9) ◽  
pp. 887-905 ◽  
Author(s):  
L. K. Mansur
Keyword(s):  
Defect Structure ◽  
Materials Science ◽  
Solute Segregation ◽  
High Dose ◽  
Physical Metallurgy ◽  
Solid Materials ◽  
The Past ◽  
Cumulative Processes ◽  
Defect Reactions ◽  
Kinetics Of

Irradiation of solid materials with energetic neutrons or charged particles can lead to profound changes in defect structure, microcomposition, and macroscopic properties. Such changes occur by atomic and microstructural mechanisms, some of which are familiar in "classical" physical metallurgy and materials science. However, other cases appear to be unique to irradiation. Irradiation has considerably broadened and indeed provided an entirely new dimension in materials science, since the energetic displacement of atoms potentially reaches to every property or process. The initial damaging events leading to the creation of point defects are generally complete in times of order 10−11 s. Subsequent changes in structure, composition, and properties take place in a span of much longer time scales corresponding to interstitial and vacancy diffusion, clustering, solute segregation, and precipitation. An extensive theoretical framework has been developed to understand the kinetics of these processes. Emphasis has been placed on both steady cumulative processes and on fluctuations, and on the appropriate application of stochastic and deterministic descriptions. Parallel and interactive experimental activities for both applied and basic programs over the past two decades have increased the level of phenomenological knowledge enormously. Much of the work has emphasized either high-dose phenomena such as irradiation-induced swelling, creep, embrittlement, phase instability, and solute segregation relevant to materials applications, or the properties, structures, and interactions of defects, which underlie more fundamental issues.

The gas-liquid transition for 12-6 argon: a grand ensemble Monte Carlo calculation

1980 ◽  
Vol 33 (4) ◽  
pp. 899
Author(s):  
JE Lane ◽  
TH Spurling
Keyword(s):  
Monte Carlo ◽  
Canonical Ensemble ◽  
Monte Carlo Calculation ◽  
Grand Canonical Ensemble ◽  
Previous Calculation ◽  
Ensemble Monte Carlo ◽  
Monte Carlo Calculations ◽  
Lennard Jones ◽  
Liquid Transition ◽  
Grand Canonical

New grand canonical ensemble Monte Carlo calculations of the gas-liquid transition for a Lennard-Jones 12-6 fluid confirm the validity of the previous calculation by Adams.

Current Status of the ASME Materials Properties Database Development

2017 ◽  
Author(s):  
Weiju Ren ◽  
Lianshan Lin
Keyword(s):  
Data File ◽  
Digital Data ◽  
Current Status ◽  
Materials Properties ◽  
Business Operation ◽  
The Past ◽  
Digital Database ◽  
Asme Code ◽  
Digital Data Processing ◽  
Future Growth

The ASME Materials Properties Database has been under development in the past few years to support the ASME Codes and Standards under the supervision of the Boiler and Pressure Vessel Code Committee on Materials. With the guidance of its Working Group on Materials Database, the project has completed the Phase I development for the Data File Warehouse that offers a depository for various files containing ASME Code Week records, materials test data from codification inquiries, and information associated with code rules development. While the database is in operation, the development has continued into Phase II to create a relational Digital Database that offers customized and relational schemas with advanced software functionalities and tools facilitating digital data processing and management. This paper discusses the current status of the project including its development management, database components and features, business operation, and future growth. Some issues and prospective resolutions for meeting the needs and requirements from Codes and Standards are also discussed.

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