Analysis of Structural Impact and Crashworthiness using Experimental, Analytical and Computational Techniques: An Overview and Recent Developments

2011 ◽  
Vol 3 (3) ◽  
Author(s):  
Yucheng Liu ◽  
Stefan Chu ◽  
Raul Viera
Keyword(s):  
Computational Techniques ◽  
Structural Impact ◽  
Recent Developments

scholarly journals Distributed X-ray photon correlation spectroscopy data reduction using Hadoop MapReduce

2018 ◽  
Vol 25 (4) ◽  
pp. 1135-1143 ◽  
Author(s):  
Faisal Khan ◽  
Suresh Narayanan ◽  
Roger Sersted ◽  
Nicholas Schwarz ◽  
Alec Sandy
Keyword(s):  
Real Time ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Frame Rate ◽  
Computational Techniques ◽  
Complex Materials ◽  
Photon Correlation ◽  
X Ray ◽  
Wide Range ◽  
Recent Developments

Multi-speckle X-ray photon correlation spectroscopy (XPCS) is a powerful technique for characterizing the dynamic nature of complex materials over a range of time scales. XPCS has been successfully applied to study a wide range of systems. Recent developments in higher-frame-rate detectors, while aiding in the study of faster dynamical processes, creates large amounts of data that require parallel computational techniques to process in near real-time. Here, an implementation of the multi-tau and two-time autocorrelation algorithms using the Hadoop MapReduce framework for distributed computing is presented. The system scales well with regard to the increase in the data size, and has been serving the users of beamline 8-ID-I at the Advanced Photon Source for near real-time autocorrelations for the past five years.

Oxygen Ion and Proton Transport in Mixed Metal Oxides

1998 ◽  
Vol 527 ◽  
Author(s):  
M. Saiful Islam
Keyword(s):  
Computational Techniques ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Recent Developments ◽  
Contemporary Work ◽  
Diffusion Mechanisms ◽  
Fresh Insight ◽  
Perovskite Type ◽  
State Ionic ◽  
Diffusion Properties

ABSTRACTComputational techniques are now well established tools in the study of structural properties and transport mechanisms in solid state ionic materials. This paper will highlight recent developments of such methods, with a strong emphasis on their use in the elucidation of ion diffusion mechanisms or pathways at the atomic level. In particular, contemporary work will be illustrated by accounts of calculations on oxygen ion and proton conduction in LaMO3 perovskite-type oxides, which find use in various electrochemical applications. We have used atomistic simulation, molecular dynamics (MD) and ab initio techniques to provide fresh insight as to their defect and ion diffusion properties.

High-resolution imaging of Σ=5 tilt boundaries in gold

1988 ◽  
Vol 46 ◽  
pp. 590-591
Author(s):  
F. Cosandey ◽  
S.-W. Chan ◽  
P. Stadelmann
Keyword(s):  
High Resolution ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Computational Models ◽  
Spherical Aberration ◽  
Computational Techniques ◽  
Recent Developments ◽  
Tilt Boundaries ◽  
High Resolution Images ◽  
Resolution Imaging

Until recently most of the information concerning the atomic structure of grain boundaries in metals has been obtained using molecular static and molecular dynamic computational techniques. With the recent developments of intermediate voltage microscope (300-400KV) this situation has changed and grain boundary atomic resolution is now possible for most metals. The purpose of this research is to examine the atomic structure of Σ=5 tilt boundaries in Au by high resolution microscopy and to compare the results to computational models.Thin film Au bicrystals containing Σ=5 (θ=36.5°±0.5) tilt grain boundaries were produced by epitaxial growth on NaCl bicrystalline substrates using a technique described in detail elsewhere. All high resolution images were obtained with a Philips 430 ST microscope using axial illumination and without objective aperture. All image simulations were obtained using the multislice formalism with EMS programs. All four {200} reflections from each crystal were used for the simulations with the following instrumental parameters; accelerating voltage V=300KV, spherical aberration constant Cs=1.1mm, defocus spread Δ=8nm and semi-angle beam divergence α=8mrad.

Two-dimensional (2D) fabrics and three-dimensional (3D) preforms for ballistic and stabbing protection: A review

2016 ◽  
Vol 87 (18) ◽  
pp. 2275-2304 ◽  
Author(s):  
Kadir Bilisik
Keyword(s):  
Impact Resistance ◽  
Three Dimensional ◽  
Shear Thickening ◽  
High Strength ◽  
Computational Techniques ◽  
Two Dimensional ◽  
Shear Thickening Fluids ◽  
Recent Developments ◽  
Ballistic Properties ◽  
The Impact

In this study, the impact resistance of two-dimensional (2D) fabrics and three-dimensional (3D) preforms is explained. These fabrics and preforms include 2D and 3D woven and knitted flat and circular fabrics. Various types of soft/layered structures as well as rigid composite are outlined with some design examples for ballistic and stab threats. The recent developments in nanotubes/nanofibers and shear-thickening fluids (STF) for ballistic fabrics are reviewed. The ballistic properties of single- and multi-layered fabrics are discussed. Their impact mechanism is explained for both soft vest and rigid armor applications. Analytical modeling and computational techniques for the estimation of ballistic properties are outlined. It is concluded that the ballistic/stab properties of fiber-reinforced soft and rigid composites can be enhanced by using high-strength fibers and tough matrices as well as specialized nanomaterials. Ballistic/stab resistance properties were also improved by the development of special fabric architectures. All these design factors are of primary importance for achieving flexible and lightweight ballistic structures with a high ballistic limit.

scholarly journals Surface crystallography by low energy electron diffraction

1998 ◽  
Vol 213 (12) ◽  
Author(s):  
K. Heinz ◽  
L. Hammer
Keyword(s):  
Electron Diffraction ◽  
Structural Information ◽  
Direct Method ◽  
Complex Surface ◽  
Low Energy ◽  
Energy Electron ◽  
Computational Techniques ◽  
Low Energy Electron Diffraction ◽  
Recent Developments ◽  
Low Energy Electron

AbstractThe present status of the methodology of full dynamical surface structure determination by low energy electron diffraction (LEED) is reviewed with respect to both experiment and theory. Restriction is to today widely used experimental and computational techniques including the powerful approach by Tensor LEED on the theoretical side. Special emphasis is on more recent developments to tackle increasingly complex surface structures. So, we describe new structural search procedures which aim to arrive at the global rather than only a local R-factor minimum in parameter space as the best fit between experiment and theory. Also, we illuminate the application of LEED to disordered adsorbates and the related development of holographic image reconstruction from diffuse diffraction patterns. The most recent extension of this direct method to ordered structures is included as well, showing that the resulting structural information is most valuable if not essential for finding the correct atomic model of the surface. Examples are given in each case and a selection of particularly demanding structure determinations is presented as well.

Computational aspects of polymorphism

2020 ◽  
pp. 215-272
Author(s):  
Joel Bernstein
Keyword(s):  
Lattice Energy ◽  
Computational Prediction ◽  
Computational Techniques ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
Conformational Polymorphism ◽  
Recent Developments ◽  
Computational Aspects ◽  
Similarities And Differences ◽  
Diffraction Patterns

The application of computational techniques to polymorphic systems is reviewed. Topics covered include the energetics of molecular geometric features (bond lengths, bond angles, torsion angles) and the energetics of intermolecular interactions of various types. Methods and techniques for the presentation of polymorphic structures are described, followed by some historically important early examples of conformational polymorphism. The latter subject is treated in light of recent developments, including some exemplary studies of conformational polymorphism and the prototypical example of “ROY” is discussed in detail. The computational prediction and comparison of polymorphs is discussed in the framework of the computational prediction of crystal structures. Methods discussed on polymorphs include the comparison based on geometric criteria, comparison based on Hirshfeld surfaces, a comparison based on energetic environment, comparison of X-ray diffraction patterns, and the use of partitioned lattice energy to investigate the details of similarities and differences in polymorphic structures.

Overview of Enhanced Continuum Theories for Thermal and Mechanical Responses of the Microsystems in the Fast-Transient Process

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
George Z. Voyiadjis ◽  
Danial Faghihi
Keyword(s):  
Computational Models ◽  
Computational Cost ◽  
Nanoindentation Test ◽  
Computational Techniques ◽  
Model Parameters ◽  
Mechanical Responses ◽  
Microscale Heat Transfer ◽  
Wide Range ◽  
Recent Developments ◽  
Continuum Theories

The recently growing demand for production and applications of microscale devices and systems has motivated research on the behavior of small volume materials. The computational models have become one of great interests in order to advance the manufacturing of microdevices and to reduce the time to insert new product in applications. Among the various numerical and computational techniques, still the approaches in the context of continuum theories are more preferable due to their minimum computational cost to simulation on realistic time and material structures. This paper reviews the methods to address the thermal and mechanical responses of microsystems. The focus is on the recent developments on the enhanced continuum theories to address the phenomena such as size and boundary effects as well as microscale heat transfer. The thermodynamic consistency of the theories is discussed and microstructural mechanisms are taken into account as physical justification of the framework. The presented constitutive model is calibrated using an extensive set of microscale experimental measurements of thin metal films over a wide range of size and temperature of the samples. An energy based approach is presented to extract the first estimate of the interface model parameters from results of nanoindentation test.

scholarly journals RAM-PGK: Prediction of Lysine Phosphoglycerylation Based on Residue Adjacency Matrix

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1524
Author(s):  
Abel Avitesh Chandra ◽  
Alok Sharma ◽  
Abdollah Dehzangi ◽  
Tatushiko Tsunoda
Keyword(s):  
Adjacency Matrix ◽  
Cell Biology ◽  
Performance Metrics ◽  
Support Vector ◽  
Computational Techniques ◽  
Identification System ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Lysine Residues ◽  
Recent Developments

Background: Post-translational modification (PTM) is a biological process that is associated with the modification of proteome, which results in the alteration of normal cell biology and pathogenesis. There have been numerous PTM reports in recent years, out of which, lysine phosphoglycerylation has emerged as one of the recent developments. The traditional methods of identifying phosphoglycerylated residues, which are experimental procedures such as mass spectrometry, have shown to be time-consuming and cost-inefficient, despite the abundance of proteins being sequenced in this post-genomic era. Due to these drawbacks, computational techniques are being sought to establish an effective identification system of phosphoglycerylated lysine residues. The development of a predictor for phosphoglycerylation prediction is not a first, but it is necessary as the latest predictor falls short in adequately detecting phosphoglycerylated and non-phosphoglycerylated lysine residues. Results: In this work, we introduce a new predictor named RAM-PGK, which uses sequence-based information relating to amino acid residues to predict phosphoglycerylated and non-phosphoglycerylated sites. A benchmark dataset was employed for this purpose, which contained experimentally identified phosphoglycerylated and non-phosphoglycerylated lysine residues. From the dataset, we extracted the residue adjacency matrix pertaining to each lysine residue in the protein sequences and converted them into feature vectors, which is used to build the phosphoglycerylation predictor. Conclusion: RAM-PGK, which is based on sequential features and support vector machine classifiers, has shown a noteworthy improvement in terms of performance in comparison to some of the recent prediction methods. The performance metrics of the RAM-PGK predictor are: 0.5741 sensitivity, 0.6436 specificity, 0.0531 precision, 0.6414 accuracy, and 0.0824 Mathews correlation coefficient.

Global optimization of an entire neutron guide hall

2011 ◽  
Vol 44 (3) ◽  
pp. 483-488 ◽  
Author(s):  
Phil M. Bentley ◽  
Peter Fouquet ◽  
Martin Böhm ◽  
Iain Sutton ◽  
Charles D. Dewhurst ◽  
...  
Keyword(s):  
Computer Games ◽  
Computational Techniques ◽  
Neutron Guide ◽  
Desktop Computer ◽  
Strongly Coupled ◽  
Figures Of Merit ◽  
Cpu Time ◽  
Recent Developments ◽  
Sample Position ◽  
Guide System

This paper describes the optimization of an entire neutron guide system, from the moderator to the sample position for several instruments simultaneously, using no more than a desktop computer and a few days of CPU time. This is made possible by merging two relatively advanced computational techniques. Neutron acceptance diagram shading is a fast new method for modelling neutron beams, using an approach based on polygons similar to those featuring in computer games. Optimization algorithms based on swarm intelligence are efficient and reliable ways to maximize numerically calculable figures of merit with many strongly coupled geometry parameters. Recent developments in these methods are described, as well as their combination to optimize the geometry of the H5 beamlines at the Institut Laue–Langevin. The optimization was such that all instruments simultaneously gain as much on-sample flux as possible by taking unused phase space from their neighbours, whilst no instrument suffers any losses in its useful flux.

Engineering Protein and Peptide Building Blocks for Nanotechnology

2007 ◽  
Vol 7 (2) ◽  
pp. 387-401 ◽  
Author(s):  
Scott Banta ◽  
Zaki Megeed ◽  
Monica Casali ◽  
Kaushal Rege ◽  
Martin L. Yarmush
Keyword(s):  
Molecular Motors ◽  
Building Blocks ◽  
Biological Synthesis ◽  
Computational Techniques ◽  
Structural Elements ◽  
Short Discussion ◽  
Safety Issues ◽  
Recent Developments ◽  
And Function ◽  
Proteins And Peptides

The tremendous diversity in the structure and function of proteins has stimulated intense interest in using them for nanotechnology applications. In this review, we discuss recent developments in the engineering of proteins and peptides for the design and construction of functional and structural elements of nanodevices. We begin with a short discussion highlighting the differences between chemical and biological synthesis of proteins and peptides. Subsequently, we review recent applications of proteins and peptides as molecular motors, transducers, biosensors, and structural elements of nanodevices. We supplement this review with highlights of our own work in the areas of peptide-based transducers for stand-alone and intra-molecular applications. This is followed by a short discussion of nanotechnology safety issues, and how proteins and peptides may enable the development of biocompatible nanomaterials. The future outlook for protein and peptide-based nanomaterials is then discussed, with an eye toward the significant impact of improved computational techniques on the field.

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