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Articles 1 - 15 of 15
Full-Text Articles in Social and Behavioral Sciences
Induced Molecular Dissociations As A Radiation Damage Descriptor (Nanodosimetry), A Traore, L Ellis-Gibbings, Alexey Verkhovtsev, K Krupa, A Munoz, Fernando Blanco, Gustavo Garcia
Induced Molecular Dissociations As A Radiation Damage Descriptor (Nanodosimetry), A Traore, L Ellis-Gibbings, Alexey Verkhovtsev, K Krupa, A Munoz, Fernando Blanco, Gustavo Garcia
Faculty of Engineering and Information Sciences - Papers: Part A
We present a nanodosimeter software based on Monte Carlo, termed: Low Energy Particle Track Simulation. For medical applications purposes, we propose bond breakings to describe the energy deposited taking water as an example. This tool aims to improve current treatment planning approach based on absorbed dose.
Single Molecular Shuttle-Junction: Shot Noise And Decoherence, Wenxi Lai, C Zhang, Zhongshui Ma
Single Molecular Shuttle-Junction: Shot Noise And Decoherence, Wenxi Lai, C Zhang, Zhongshui Ma
Faculty of Engineering and Information Sciences - Papers: Part A
Single molecular shuttle-junction is one kind of nanoscale electromechanical tunneling system. In this junction, a molecular island oscillates depending on its charge occupation, and this charge dependent oscillation leads to modulation of electron tunneling through the molecular island. This paper reviews recent development on the study of current, shot noise and decoherence of electrons in the single molecular shuttle-junction. We will give detail discussions on this topic using the typical system model, the theory of fully quantum master equation and the Aharonov-Bohm interferometer.
Brittle Versus Ductile Behaviour Of Nanotwinned Copper: A Molecular Dynamics Study, Linqing Pei, Cheng Lu, Xing Zhao, Liang Zhang, Kuiyu Cheng, Guillaume Michal, A Kiet Tieu
Brittle Versus Ductile Behaviour Of Nanotwinned Copper: A Molecular Dynamics Study, Linqing Pei, Cheng Lu, Xing Zhao, Liang Zhang, Kuiyu Cheng, Guillaume Michal, A Kiet Tieu
Faculty of Engineering and Information Sciences - Papers: Part A
Nanotwinned copper (Cu) exhibits an unusual combination of ultra-high yield strength and high ductility. A brittle-to-ductile transition was previously experimentally observed in nanotwinned Cu despite Cu being an intrinsically ductile metal. However, the atomic mechanisms responsible for brittle fracture and ductile fracture in nanotwinned Cu are still not clear. In this study, molecular dynamics (MD) simulations at different temperatures have been performed to investigate the fracture behaviour of a nanotwinned Cu specimen with a single-edge-notched crack whose surface coincides with a twin boundary. Three temperature ranges are identified, indicative of distinct fracture regimes, under tensile straining perpendicular to the twin …
Molecular Dynamics Simulation On Generalized Stacking Fault Energies Of Fcc Metals Under Preloading Stress, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei, Guillaume Michal
Molecular Dynamics Simulation On Generalized Stacking Fault Energies Of Fcc Metals Under Preloading Stress, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei, Guillaume Michal
Faculty of Engineering and Information Sciences - Papers: Part A
Molecular dynamics (MD) simulations are performed to investigate the effects of stress on generalized stacking fault (GSF) energy of three fcc metals (Cu, Al, and Ni). The simulation model is deformed by uniaxial tension or compression in each of [111], [11-2], and [1-10] directions, respectively, before shifting the lattice to calculate the GSF curve. Simulation results show that the values of unstable stacking fault energy (γusf), stable stacking fault energy (γsf), and unstable twin fault energy (γutf) of the three elements can change with the preloaded tensile or compressive stress in different directions. The ratio of γsf/γusf, which is related …
The Shear Response Of Copper Bicrystals With Σ11 Symmetric And Asymmetric Tilt Grain Boundaries By Molecular Dynamics Simulation, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei
The Shear Response Of Copper Bicrystals With Σ11 Symmetric And Asymmetric Tilt Grain Boundaries By Molecular Dynamics Simulation, Liang Zhang, Cheng Lu, A Kiet Tieu, Xing Zhao, Linqing Pei
Faculty of Engineering and Information Sciences - Papers: Part A
Grain boundaries (GBs) are important microstructure features and can significantly affect the properties of nanocrystalline materials. Molecular dynamics simulation was carried out in this study to investigate the shear response and deformation mechanisms of symmetric and asymmetric Σ11 tilt GBs in copper bicrystals. Different deformation mechanisms were reported, depending on GB inclination angles and equilibrium GB structures, including GB migration coupled to shear deformation, GB sliding caused by local atomic shuffling, and dislocation nucleation from GB. The simulation showed that migrating Σ11(1 1 3) GB under shear can be regarded as sliding of GB dislocations and their combination along the …
Molecular Dynamics Study On The Grain Boundary Dislocation Source In Nanocrystalline Copper Under Tensile Loading, Liang Zhang, Cheng Lu, A Kiet Tieu, Linqing Pei, Xing Zhao, Kuiyu Cheng
Molecular Dynamics Study On The Grain Boundary Dislocation Source In Nanocrystalline Copper Under Tensile Loading, Liang Zhang, Cheng Lu, A Kiet Tieu, Linqing Pei, Xing Zhao, Kuiyu Cheng
Faculty of Engineering and Information Sciences - Papers: Part A
Grain boundary (GB) is the interface between different oriented crystals of the same material, and it can have a significant effect on the many properties of materials. When the average or entire range of grain size is reduced to less than 100 nm, the conventional plastic deformation mechanisms dominated by dislocation processes become difficult and GBmediated deformation mechanisms become increasingly important. One of the mechanisms that can play a profound role in the strength and plasticity of metallic polycrystalline materials is the heterogeneous nucleation and emission of dislocations from GB. In this study, we conducted molecular dynamics simulations to study …
The Role Of Pyrimidine And Water As Underlying Molecular Constituents For Describing Radiation Damage In Living Tissue: A Comparative Study, Martina C. Fuss, L Ellis-Gibbings, Darryl B. Jones, M J. Brunger, Francisco Blanco, A Muñoz, Paulo Limao-Vieira, Gustavo Garcia
The Role Of Pyrimidine And Water As Underlying Molecular Constituents For Describing Radiation Damage In Living Tissue: A Comparative Study, Martina C. Fuss, L Ellis-Gibbings, Darryl B. Jones, M J. Brunger, Francisco Blanco, A Muñoz, Paulo Limao-Vieira, Gustavo Garcia
Faculty of Engineering and Information Sciences - Papers: Part A
Water is often used as the medium for characterizing the effects of radiation on living tissue. However, in this study, charged-particle track simulations are employed to quantify the induced physicochemical and potential biological implications when a primary ionising particle with energy 10 keV strikes a medium made up entirely of water or pyrimidine. Note that pyrimidine was chosen as the DNA/RNA bases cytosine, thymine, and uracil can be considered pyrimidine derivatives. This study aims to assess the influence of the choice of medium on the charged-particle transport, and identify how appropriate it is to use water as the default medium …
Novel Experimental Setup For Time-Of-Flight Mass Spectrometry Ion Detection In Collisions Of Anionic Species With Neutral Gas-Phase Molecular Targets, J C. Oller, L Ellis-Gibbings, F Ferreira Da Silva, Paulo Limao-Vieira, Gustavo Garcia
Novel Experimental Setup For Time-Of-Flight Mass Spectrometry Ion Detection In Collisions Of Anionic Species With Neutral Gas-Phase Molecular Targets, J C. Oller, L Ellis-Gibbings, F Ferreira Da Silva, Paulo Limao-Vieira, Gustavo Garcia
Faculty of Engineering and Information Sciences - Papers: Part A
We report a novel experimental setup for studying collision induced products resulting from the interaction of anionic beams with a neutral gas-phase molecular target. The precursor projectile was admitted into vacuum through a commercial pulsed valve, with the anionic beam produced in a hollow cathode discharge-induced plasma, and guided to the interaction region by a set of deflecting plates where it was made to interact with the target beam. Depending on the collision energy regime, negative and positive species can be formed in the collision region and ions were time-of-flight (TOF) mass-analysed. Here, we present data on O-2 precursor projectile, …
Response Of The Al Σ5 〈001〉 Left {310} Symmetric Tilt Grain Boundary To The Shear Deformation Simulated By Molecular Dynamics, Kuiyu Cheng, Cheng Lu, A Kiet Tieu
Response Of The Al Σ5 〈001〉 Left {310} Symmetric Tilt Grain Boundary To The Shear Deformation Simulated By Molecular Dynamics, Kuiyu Cheng, Cheng Lu, A Kiet Tieu
Faculty of Engineering and Information Sciences - Papers: Part A
In the present study, shear response of the Al [001] symmetrical tilting Σ5 (310) grain boundary (GB) was investigated by a three dimensional bicrystal at 500~750 K. It was found that the GB gradually rotated around the [001] tilt axis during the shear deformation due to the combination of surface strain, GB sliding and GB coupled motion. These rotated grain boundaries were Σ5 asymmetrical or symmetrical tilt grain boundaries and led to the normal stress σxx in the bicrystal system. It was also found that the response of the grain boundary to the shear deformation was closely related to the …
Molecular Dynamics Simulation On Σ5 Grain Boundaries Of Copper Bicrystal Under Tensile And Shear Deformation, Liang Zhang, Cheng Lu, A Kiet Tieu
Molecular Dynamics Simulation On Σ5 Grain Boundaries Of Copper Bicrystal Under Tensile And Shear Deformation, Liang Zhang, Cheng Lu, A Kiet Tieu
Faculty of Engineering and Information Sciences - Papers: Part A
Molecular Dynamics simulation are employed to investigate the structures and mechanical behavior of both symmetric and asymmetric Σ5[0 0 1] tilt grain boundaries (GBs) of copper bicrystal under uniaxial tension and shear deformation. Simulation results indicate that the Σ5 asymmetric GBs can facet into their corresponding symmetric GB structures. The maximum tensile stress of symmetric GBs is higher than the asymmetric ones at both 10 K and 300 K, which suggests the symmetric GBs may have a more stable boundary structures. All the Σ5 GBs investigate in this study can migrate under the shear deformation with different velocity. The migration …
Molecular Weight Distribution Of Network Strands In Double Network Hydrogels Estimated By Mechanical Testing, Hai Xin, Hugh Ralph Brown, Geoffrey M. Spinks
Molecular Weight Distribution Of Network Strands In Double Network Hydrogels Estimated By Mechanical Testing, Hai Xin, Hugh Ralph Brown, Geoffrey M. Spinks
Faculty of Engineering and Information Sciences - Papers: Part A
The remarkably high toughness of double network (DN) hydrogels is related to the energy dissipation that occurs due to the scission of network strands in the most tightly crosslinked of its two interpenetrating networks. The loading curve during tensile testing of DN hydrogels usually takes a complex shape and sometimes shows yielding. Wang and Hong recently proposed a model [1] based on the successive scission of the shortest remaining elastically active strands during tensile loading that predicts the shape of the loading curve of one DN hydrogel reasonably well. In the present study, the model was modified slightly and applied …
A Molecular Dynamics Simulation Of Fracture In Nanocrystalline Copper, Linqing Pei, Cheng Lu, Kiet Tieu, Hongtao Zhu, Xing Zhao, Kuiyu Cheng, Liang Zhang
A Molecular Dynamics Simulation Of Fracture In Nanocrystalline Copper, Linqing Pei, Cheng Lu, Kiet Tieu, Hongtao Zhu, Xing Zhao, Kuiyu Cheng, Liang Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
A large-scale molecular dynamics simulation was used to investigate the propagation of cracks in three dimensional samples of nanocrystalline copper, with average grain sizes ranging from 5.34 to 14.8 nm and temperatures ranging from 1K to 500 K. It was shown that intragranular fracture can proceed inside the grain at low temperature, and plastic deformation around the tip of the crack is accommodated by dislocation nucleation/emission; indeed, both fully extended dislocation and deformation twinning were visible around the tip of the crack during fracture. In addition, due to a higher concentration of stress in front of the crack at a …
Predicting The Fate Of Emerging Trace Organic Contaminants Of Concern During Mbr Treatment Based On Their Molecular Properties, K C. Wijekoon, L D. Nghiem, F I. Hai, J Kang, W E. Price
Predicting The Fate Of Emerging Trace Organic Contaminants Of Concern During Mbr Treatment Based On Their Molecular Properties, K C. Wijekoon, L D. Nghiem, F I. Hai, J Kang, W E. Price
Faculty of Engineering and Information Sciences - Papers: Part A
We demonstrate that the fate of emerging trace organic contaminants during membrane bioreactor (MBR) treatment can be qualitatively predicted by assessing their molecular properties. This work futher expands the qualitative framework for the prdiction of trace organic removal by MBR treatment reported in our recent study.
Molecular Epidemiology Of A Fast-Food Restaurant-Associated Outbreak Of Escherichia Coli O157:H7 In Washington State, Linda M. Grimm, Marcia Goldoft, John Kobayashi, Jay H. Lewis, Dalia Alfi, Ann Marie Perdichizzi, Phillip I. Tarr, Jerry E. Ongerth, Steve L. Moseley, Mansour Samadpour
Molecular Epidemiology Of A Fast-Food Restaurant-Associated Outbreak Of Escherichia Coli O157:H7 In Washington State, Linda M. Grimm, Marcia Goldoft, John Kobayashi, Jay H. Lewis, Dalia Alfi, Ann Marie Perdichizzi, Phillip I. Tarr, Jerry E. Ongerth, Steve L. Moseley, Mansour Samadpour
Faculty of Engineering and Information Sciences - Papers: Part A
We studied the molecular epidemiology of the recent fast-food restaurant chain-associated Escherichia coli O157:H7 outbreak in Washington State. Genomic DNAs prepared from strains isolated from 433 patients were probed with radiolabelled Shiga-like toxin (SLT) I and SLT II genes and bacteriophage l DNA and were subsequently analyzed for their restriction fragment length polymorphism (RFLP) patterns. The SLT RFLP and l RFLP profiles of an E. coli O157:H7 strain isolated from the incriminated beef and prototype patient were compared with those of the patient isolates for determination of the concordance between patterns. Of the 377 patients with primary and secondary cases …
Molecular Epidemiology Of Escherichia Coli 0157:H7 Strains By Bacteriophage A Restriction Fragment Length Polymorphism Analysis: Application To A Multistate Foodborne Outbreak And A Day-Care Center Cluster, Mansour Samadpour, Linda M. Grimm, B Desai, Dalia Alfi, Jerry E. Ongerth, Phillip I. Tarr
Molecular Epidemiology Of Escherichia Coli 0157:H7 Strains By Bacteriophage A Restriction Fragment Length Polymorphism Analysis: Application To A Multistate Foodborne Outbreak And A Day-Care Center Cluster, Mansour Samadpour, Linda M. Grimm, B Desai, Dalia Alfi, Jerry E. Ongerth, Phillip I. Tarr
Faculty of Engineering and Information Sciences - Papers: Part A
Genomic DNAs prepared from 168 isolates of Escherichia coli 0157:H7 were analyzed for restriction fragment length polymorphisms on Southern blots probed with bacteriophage A DNA. The isolates analyzed included strains from a recent large multistate outbreak of E. coli 0157:H7 infection associated with consumption of poorly cooked beef in restaurants, a day-care center cluster, and temporally and geographically unrelated isolates. E. coli 0157:H7 isolates recovered from the incriminated meat and from 61 (96.8%) of 63 patients from Washington and Nevada possessed identical A restriction fragment length patterns. The A restriction fragment length polymorphisms observed in 11 (91.7%) of 12 day-care …