scholarly journals 4D Soft Material Systems

2021 ◽  
pp. 201-210
Author(s):  
Giulia Grassi ◽  
Bjorn Sparrman ◽  
Ingrid Paoletti ◽  
Skylar Tibbits
Keyword(s):  
Soft Material ◽  
Material Composition ◽  
Enabling Technology ◽  
Swelling Behaviour ◽  
Wide Range ◽  
Material Systems

AbstractThis work introduces multi-material liquid printing as an enabling technology for designing programmed shape-shifting silicones. The goal of this research is to provide a readily available, scalable and customized approach at producing responsive 4D printed structures for a wide range of applications. Hence, the methodology allows customization at each step of the procedure by intervening either on the material composition and/or on the design and fabrication strategies for the production of responsive components. A significant endeavour is initiated to develop and engineer two different material systems that enable shape-shifting: silicone-ethanol composites and polyvinyl siloxane swelling rubbers. The printed samples successfully comply with the expected swelling behaviour through a variety of printed test patterns.

Recombination-enhanced Dislocation Glides—The Current Status of Knowledge

2009 ◽  
Vol 1195 ◽  
Author(s):  
Koji Maeda
Keyword(s):  
Research Progress ◽  
Current Status ◽  
Bipolar Devices ◽  
Wide Range ◽  
Material Systems ◽  
The Status

AbstractTo update the status of knowledge on the recombination-enhanced dislocation glides (REDG) in semiconductors, which is one of the causes of serious degradation in bipolar devices, research progress achieved for the last decade has been surveyed. Rather than presenting a complete review over a wide range of material systems, a particular attention has been paid to the REDG effect in 4H-SiC for which a lot of information has been accumulated owing to extensive studies. Although the REDG effect exhibits features that could be interpreted in terms of the phonon-kick mechanism, conclusive proof is still lacking.

Recombination-enhanced Dislocation Glides—The Current Status of Knowledge

2009 ◽  
Vol 1195 ◽  
Author(s):  
Koji Maeda
Keyword(s):  
Research Progress ◽  
Current Status ◽  
Bipolar Devices ◽  
Wide Range ◽  
Material Systems ◽  
The Status

AbstractTo update the status of knowledge on the recombination-enhanced dislocation glides (REDG) in semiconductors, which is one of the causes of serious degradation in bipolar devices, research progress achieved for the last decade has been surveyed. Rather than presenting a complete review over a wide range of material systems, a particular attention has been paid to the REDG effect in 4H-SiC for which a lot of information has been accumulated owing to extensive studies. Although the REDG effect exhibits features that could be interpreted in terms of the phonon-kick mechanism, conclusive proof is still lacking.

Water governance challenges presented by nanotechnologies: tracking, identifying and quantifying nanomaterials (the ultimate disparate source) in our waterways

2016 ◽  
Vol 47 (3) ◽  
pp. 552-568 ◽  
Author(s):  
Iseult Lynch
Keyword(s):  
Water Governance ◽  
High Surface ◽  
Consumer Products ◽  
Direct Access ◽  
Enabling Technology ◽  
Multiple Products ◽  
Wide Range ◽  
Governance Challenges ◽  
Multiple Routes ◽  
Disparate Source

Nanotechnologies are considered an enabling technology, as they enhance the functioning of a wide range of products and processes. They are increasingly appearing in consumer products, including sun creams, socks and outdoor paints, resulting in the potential for direct access of nanomaterials (NMs) into wastewater and the environment. As such, they could be considered as the ultimate disparate source, with multiple products and multiple routes into the environment, as well as numerous transformation pathways, such that the final form may bear little resemblance to the initially produced form. NMs thus represent a significant governance and regulatory challenge, for a number of reasons, related to their small size, which makes detection challenging, especially against a background of naturally occurring nanoscale entities (clay and sediment particles, etc.), and their large surface area and high surface energy which leads to very dynamic behaviour and a strong tendency to interact with (bind) anything they come into contact with. Some initial considerations of regulatory issues related to Registration, Evaluation and Authorization of Chemicals, the Water Framework Directive, and the potential for benign-by-design approaches exploiting the potential for recovery or recycling of NMs at the design phase are presented, aimed at reducing the risk of unintentional accumulation of NMs in our waterways.

Computational Discovery of Molecular C60 Encapsulants with an Evolutionary Algorithm

2019 ◽  
Author(s):  
Marcin Miklitz ◽  
Lukas Turcani ◽  
Rebecca L. Greenaway ◽  
Kim Jelfs
Keyword(s):  
Evolutionary Algorithm ◽  
Chemical Space ◽  
Fitness Function ◽  
Building Blocks ◽  
Fullerene C60 ◽  
Cavity Size ◽  
Structural Symmetry ◽  
Wide Range ◽  
Material Systems ◽  
Computational Discovery

<p>A function-led computational discovery using an evolutionary algorithm was used to find potential fullerene (C60) encapsulants within the chemical space of porous organic cages. This makes use of a tailored fitness function that includes consideration of the interaction energy between the cage and the C60 molecule, the shape persistence of the cage, and the symmetry of the assemblies. We find that the promising host cages for C60 evolve over the simulations towards systems that share features such as the correct cavity size to host C60, planar tri-topic aldehyde building blocks with a small number of rotational bonds, di-topic amine linkers with functionality on adjacent carbon atoms, high structural symmetry, and strong complex binding affinity towards C60. The proposed cages are chemically feasible and similar to cages already present in the literature, helping to increase the likelihood of the future synthetic realisation of these predictions. The presented approach is highly generalisable and can be tailored to target a wide range of properties in molecular encapsulants or other molecular material systems.</p>

Computational Discovery of Molecular C60 Encapsulants with an Evolutionary Algorithm

2019 ◽  
Author(s):  
Marcin Miklitz ◽  
Lukas Turcani ◽  
Rebecca L. Greenaway ◽  
Kim Jelfs
Keyword(s):  
Evolutionary Algorithm ◽  
Chemical Space ◽  
Fitness Function ◽  
Building Blocks ◽  
Fullerene C60 ◽  
Cavity Size ◽  
Structural Symmetry ◽  
Wide Range ◽  
Material Systems ◽  
Computational Discovery

<p>A function-led computational discovery using an evolutionary algorithm was used to find potential fullerene (C60) encapsulants within the chemical space of porous organic cages. This makes use of a tailored fitness function that includes consideration of the interaction energy between the cage and the C60 molecule, the shape persistence of the cage, and the symmetry of the assemblies. We find that the promising host cages for C60 evolve over the simulations towards systems that share features such as the correct cavity size to host C60, planar tri-topic aldehyde building blocks with a small number of rotational bonds, di-topic amine linkers with functionality on adjacent carbon atoms, high structural symmetry, and strong complex binding affinity towards C60. The proposed cages are chemically feasible and similar to cages already present in the literature, helping to increase the likelihood of the future synthetic realisation of these predictions. The presented approach is highly generalisable and can be tailored to target a wide range of properties in molecular encapsulants or other molecular material systems.</p>

scholarly journals Assuring the Machine Learning Lifecycle

2021 ◽  
Vol 54 (5) ◽  
pp. 1-39
Author(s):  
Rob Ashmore ◽  
Radu Calinescu ◽  
Colin Paterson
Keyword(s):  
Machine Learning ◽  
Iterative Process ◽  
State Of The Art ◽  
The State ◽  
Enabling Technology ◽  
Safety Critical ◽  
Wide Range ◽  
Comprehensive Survey ◽  
Intended Use

Machine learning has evolved into an enabling technology for a wide range of highly successful applications. The potential for this success to continue and accelerate has placed machine learning (ML) at the top of research, economic, and political agendas. Such unprecedented interest is fuelled by a vision of ML applicability extending to healthcare, transportation, defence, and other domains of great societal importance. Achieving this vision requires the use of ML in safety-critical applications that demand levels of assurance beyond those needed for current ML applications. Our article provides a comprehensive survey of the state of the art in the assurance of ML , i.e., in the generation of evidence that ML is sufficiently safe for its intended use. The survey covers the methods capable of providing such evidence at different stages of the machine learning lifecycle , i.e., of the complex, iterative process that starts with the collection of the data used to train an ML component for a system, and ends with the deployment of that component within the system. The article begins with a systematic presentation of the ML lifecycle and its stages. We then define assurance desiderata for each stage, review existing methods that contribute to achieving these desiderata, and identify open challenges that require further research.

A Multi-Method Analysis of Carburized Materials: Accurately Measuring the Carbon Gradient and Comparisons to Physical Characteristics

2021 ◽  
Author(s):  
Allen C. Metz ◽  
Dave B. Coulston ◽  
Andrew P. Storey ◽  
Lloyd A. Allen
Keyword(s):  
Glow Discharge ◽  
Surface Hardness ◽  
Base Material ◽  
Careful Consideration ◽  
Material Composition ◽  
Near Surface ◽  
Glow Discharge Spectroscopy ◽  
Wide Range ◽  
Hardened Case ◽  
Complementary Techniques

Abstract Carburization is a common method of hardening steel surfaces to be wear-resistant for a wide range of mechanical processes. One critical characteristic of the carburization process is the increase in carbon content that leads to the formation of martensite in the surface layer. Combustion and spark-OES are two common methods for determination of carbon in steels. However, these techniques do not effectively separate carbon from near surface contaminants, carburized layers, and base material composition. Careful consideration of glow discharge spectroscopy as a method of precisely characterizing carbon concentration in surface layers as part of a production process should be evaluated in terms of how the resulting data align with other common analytical and metallurgical measurements. When used together, glow discharge spectroscopy, optical microscopy, and microhardness testing are all useful, complementary techniques for characterizing the elemental composition, visually observable changes in material composition, and changes in surface hardness throughout the hardened case, respectively. Close agreement between related measurements can be used to support the use of each of these techniques as part of a strong quality program for heat treatment facilities.

Computational Discovery of Molecular C60 Encapsulants with an Evolutionary Algorithm

2019 ◽  
Author(s):  
Marcin Miklitz ◽  
Lukas Turcani ◽  
Rebecca L. Greenaway ◽  
Kim Jelfs
Keyword(s):  
Evolutionary Algorithm ◽  
Chemical Space ◽  
Fitness Function ◽  
Building Blocks ◽  
Fullerene C60 ◽  
Cavity Size ◽  
Structural Symmetry ◽  
Wide Range ◽  
Material Systems ◽  
Computational Discovery

<p>A function-led computational discovery using an evolutionary algorithm was used to find potential fullerene (C60) encapsulants within the chemical space of porous organic cages. This makes use of a tailored fitness function that includes consideration of the interaction energy between the cage and the C60 molecule, the shape persistence of the cage, and the symmetry of the assemblies. We find that the promising host cages for C60 evolve over the simulations towards systems that share features such as the correct cavity size to host C60, planar tri-topic aldehyde building blocks with a small number of rotational bonds, di-topic amine linkers with functionality on adjacent carbon atoms, high structural symmetry, and strong complex binding affinity towards C60. The proposed cages are chemically feasible and similar to cages already present in the literature, helping to increase the likelihood of the future synthetic realisation of these predictions. The presented approach is highly generalisable and can be tailored to target a wide range of properties in molecular encapsulants or other molecular material systems.</p>

Alignment and Deposition of Single Wall Carbon Nanotubes under the Influence of an Electric Field

2002 ◽  
Vol 761 ◽  
Author(s):  
Paul Jaynes ◽  
Thomas Tiano ◽  
Margaret Roylance ◽  
Charles Carey ◽  
Kenneth McElrath
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Electronic Devices ◽  
Physical And Mechanical Properties ◽  
Single Wall Carbon Nanotubes ◽  
Enabling Technology ◽  
Single Wall Carbon ◽  
Nanoelectronic Devices ◽  
Wide Range ◽  
Field Lines

ABSTRACTSingle wall carbon nanotubes have aroused a great deal of interest because of their unique combination of electrical, physical and mechanical properties. However, the widespread use of SWNTs in composites and electronic devices is limited because of the difficulty of dispersing and processing these materials. This paper describes a method for depositing and aligning SWNTs from a dispersed solution onto a substrate under the influence of an electric field. Results indicate that SWNTs can be aligned in bulk in the direction of electric field lines, and that individual SWNT ropes may be deposited between two electrodes. The extent and type of deposition depends upon the electrode geometry and processing time. Electrical alignment of SWNTs is an enabling technology allowing manipulation of nanomaterials using standard processing. It could eventually lead to a wide range of products, such as nanocomposites with aligned fillers and nanoelectronic devices.

Phase transition and swelling behaviour of different starch granules over a wide range of water content

LWT ◽  
2014 ◽  
Vol 59 (2) ◽  
pp. 597-604 ◽  
Author(s):  
Shujun Wang ◽  
Caili Li ◽  
Jinglin Yu ◽  
Les Copeland ◽  
Shuo Wang
Keyword(s):  
Phase Transition ◽  
Water Content ◽  
Starch Granules ◽  
Swelling Behaviour ◽  
Wide Range
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