Properties and Applications of Dry-Spun Carbon Nanotube Yarns

2008 ◽  
Vol 60 ◽  
pp. 11-20 ◽  
Author(s):  
Ken R. Atkinson ◽  
Chris Skourtis ◽  
S.R. Hutton
Keyword(s):  
Biomedical Applications ◽  
High Strength ◽  
Practical Applications ◽  
Good Thermal Stability ◽  
University Of Texas ◽  
Mechanical And Electrical Properties ◽  
State Process ◽  
Large Numbers ◽  
Technical Interest ◽  
Reliable Methods

Carbon nanotubes (CNTs) are of great technical interest because of their high strength (~37 GPa), good electrical conductivity, excellent thermal conductivity (3 000 W m-1K-1), and good thermal stability at both low and high temperatures. A difficulty has been absence of reliable methods of controlling assembly of the large numbers of CNTs required for practical applications. We have developed, in collaboration with our partners at the NanoTech Institute, University of Texas at Dallas, a solid-state process for spinning CNTs into yarns without the use of binders that usually degrade the electrical and thermal conductivities. The singles yarns were twisted together to give coarser (multi-stranded) stronger yarns that were knitted using a miniature 5-needle machine. Mechanical and electrical properties of the yarns and knitted tubes were assessed simultaneously using specially developed test equipment. Some specific applications under investigation include using the CNT yarns as incandescent and x-ray filaments, as electrodes for biomedical applications, and as composites with high toughness. Tests show the biocompatibility of the CNT yarns for selected cell lines is high.

HREM interface studies in SiC-whisker-reinforced Al2O3 and Si3N4 ceramics

1988 ◽  
Vol 46 ◽  
pp. 734-735
Author(s):  
W. Braue ◽  
R.W. Carpenter ◽  
D.J. Smith
Keyword(s):  
Analytical Data ◽  
Base Material ◽  
High Strength ◽  
Ceramic Composites ◽  
Good Thermal Stability ◽  
All Ceramic ◽  
Sic Whiskers ◽  
Base Composite ◽  
C 30 ◽  
Si3n4 Ceramics

Whisker and fiber reinforcement has been established as an effective toughening concept for monolithic structural ceramics to overcome limited fracture toughness and brittleness. SiC whiskers in particular combine both high strength and elastic moduli with good thermal stability and are compatible with most oxide and nonoxide matrices. As the major toughening mechanisms - crack branching, deflection and bridging - in SiC whiskenreinforced Al2O3 and Si3N41 are critically dependent on interface properties, a detailed TEM investigation was conducted on whisker/matrix interfaces in these all-ceramic- composites.In this study we present HREM images obtained at 400 kV from β-SiC/α-Al2O3 and β-SiC/β-Si3N4 interfaces, as well as preliminary analytical data. The Al2O3- base composite was hotpressed at 1830 °C/60 MPa in vacuum and the Si3N4-base material at 1725 °C/30 MPa in argon atmosphere, respectively, adding a total of 6 vt.% (Y2O3 + Al2O3) to the latter to promote densification.

Diagnostics of metal samples using the results of experimental and theoretical study of positively charged microparticles formed upon sample destruction

2018 ◽  
Vol 84 (10) ◽  
pp. 23-28
Author(s):  
D. A. Golentsov ◽  
A. G. Gulin ◽  
Vladimir A. Likhter ◽  
K. E. Ulybyshev
Keyword(s):  
Experimental Data ◽  
Early Stage ◽  
Experimental Studies ◽  
Material Model ◽  
Total Charge ◽  
Cross Sectional ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Order Of Magnitude ◽  
Using Data

Destruction of bodies is accompanied by formation of both large and microscopic fragments. Numerous experiments on the rupture of different samples show that those fragments carry a positive electric charge. his phenomenon is of interest from the viewpoint of its potential application to contactless diagnostics of the early stage of destruction of the elements in various technical devices. However, the lack of understanding the nature of this phenomenon restricts the possibility of its practical applications. Experimental studies were carried out using an apparatus that allowed direct measurements of the total charge of the microparticles formed upon sample rupture and determination of their size and quantity. The results of rupture tests of duralumin and electrical steel showed that the size of microparticles is several tens of microns, the particle charge per particle is on the order of 10–14 C, and their amount can be estimated as the ratio of the cross-sectional area of the sample at the point of discontinuity to the square of the microparticle size. A model of charge formation on the microparticles is developed proceeding from the experimental data and current concept of the electron gas in metals. The model makes it possible to determine the charge of the microparticle using data on the particle size and mechanical and electrical properties of the material. Model estimates of the total charge of particles show order-of-magnitude agreement with the experimental data.

scholarly journals Intersection Sight Distance Characteristics of Turbo Roundabouts

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Akshay Salwan ◽  
Said M. Easa ◽  
Narayana Raju ◽  
Shriniwas Arkatkar
Keyword(s):  
North America ◽  
Mathematical Optimization ◽  
Critical Parameters ◽  
Practical Applications ◽  
Sight Distance ◽  
Large Numbers ◽  
Mathematical Formulas ◽  
Lateral Clearance ◽  
Intersection Geometry ◽  
Mathematical Characteristics

A turbo roundabout uses spiral circulatory roads for effectively counteracting the problems faced in modern multilane roundabouts. First developed in 1996, the turbo roundabout has an advantage over the conventional roundabout regarding capacity and safety. Turbo roundabouts are still in the developing phase in North America, but even in the European subcontinent where they exist in large numbers, reliable analytical studies on the critical parameters of roundabout visibility are lacking. Visibility (sight distance) helps to shape the geometry of the intersection and aids in safety. This paper presents the mathematical characteristics of the intersection geometry and intersection sight distance (ISD) of the turbo roundabout. Mathematical formulas are presented for the sight distance from the approaching vehicle to the conflicting-entering and circulating vehicles. The maximum lateral clearances to the conflicting vehicles are derived using mathematical optimization. The developed analytical method is verified graphically using AutoCAD. To assist in practical applications, design aids for the maximum lateral clearance are presented. The presented method and design aids should aid in promoting safety at turbo roundabouts.

High partial thermal conductivity of luminescence sites: a crucial factor for reducing the heat-induced lowering of the luminescence efficiency

2021 ◽  
Author(s):  
Ni Luo ◽  
Jing Xu ◽  
Xiyue Cheng ◽  
ZhenHua Li ◽  
Yidong Huang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Practical Applications ◽  
Good Thermal Stability ◽  
The Past ◽  
Luminescence Efficiency ◽  
Thermal Stability Of

The good thermal stability of a phosphor is crucial for its practical applications. Unfortunately, in the past decades, only Gurney-Mott equation was available to describe the relation between the luminescence...

scholarly journals A β-type TiNbZr alloy with low modulus and high strength for biomedical applications

2014 ◽  
Vol 24 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Qingkun Meng ◽  
Shun Guo ◽  
Qing Liu ◽  
Liang Hu ◽  
Xinqing Zhao
Keyword(s):  
Biomedical Applications ◽  
High Strength ◽  
Low Modulus

scholarly journals High Strength Metallurgical Graphene – Mechanisms of Growth and Properties / Grafen Metalurgiczny O Wysokiej Wytrzymałości – Mechanizmy Wzrostu I Właściwości

2015 ◽  
Vol 60 (4) ◽  
pp. 2535-2542 ◽  
Author(s):  
P. Kula ◽  
W. Szymański ◽  
Ł. Kołodziejczyk ◽  
R. Atraszkiewicz ◽  
K. Dybowski ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Chemical Vapor ◽  
High Strength ◽  
Growth Mechanisms ◽  
Key Factors ◽  
Mechanical And Electrical Properties ◽  
Chemical Vapor Deposited ◽  
Graphene Flakes

In this work, the growth mechanisms of chemical vapor deposited and metallurgical graphene and their selected mechanical and electrical properties were investigated. The study revealed the influence of the growth mechanisms on monoand poly-crystalline nanostructures of synthesized graphene monolayers. The structure of flake boundaries greatly affects both the mechanical and electrical properties. The key factors are overlapping of the graphene flakes, their degree of mismatch and the presence of π type bonds. All of these issues should be taken into account when developing industrially scaled technologies for graphene manufacturing.

Characterization and comparison of properties of cryogenic conditioned CNT reinforced thermoset (epoxy) and thermoplastic (poly vinyl alcohol) composite yarns

2021 ◽  
pp. 002199832110417
Author(s):  
Wei Chen ◽  
Yifan Wang ◽  
Kun Zhang ◽  
Fujun Xu
Keyword(s):  
Tensile Strength ◽  
Vinyl Alcohol ◽  
Thermoplastic Composite ◽  
Advanced Materials ◽  
Poly Vinyl Alcohol ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Composite Yarn ◽  
Thermoset Epoxy ◽  
New Generation

Carbon nanotube (CNT) fiber/yarn reinforced composites are considered as a new generation of advanced materials for applications in aerospace and space industry. In this study, two types of CNT composite yarns were produced by twisting CNT films and infiltrating with thermoset epoxy (EP) and thermoplastic poly vinyl alcohol (PVA) resins. The tensile strength of CNT/PVA and CNT/EP composite yarn was 409.91 MPa and 206.87 MPa, much higher than that of pure CNT yarn (129.94 MPa). After mono-cryogenic condition, the mechanical and electrical properties of CNT/EP and CNT/PVA composite yarns were both enhanced due to the structure reorder of the CNT bundles and improvement of interfacial bonding. However, after 60 times cyclic-cryogenic conditions, CNT/EP composite yarn showed a ∼10% degradation of tensile strength; while CNT/PVA composite yarn exhibited 6% increment. This study provides fundamental data of the CNT reinforced thermoset and thermoplastic composite yarns for their practical applications in cryogenic environment.

The Study of Wooden Clamps for Strengthening of Connection on Bamboo Truss Structure

2015 ◽  
Vol 72 (5) ◽  
Author(s):  
Astuti Masdar ◽  
Bambang Suhendro ◽  
Suprapto Siswosukarto ◽  
Djoko Sulistyo
Keyword(s):  
Construction Projects ◽  
Lower Cost ◽  
High Strength ◽  
Truss Structure ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Practical Applications ◽  
Lower Weight ◽  
Connection System ◽  
Plate System

High strength bamboo material cannot be fully utilized in construction projects due to the constraints of the connection system. The connection system element on the truss structure greatly affects the strength of the structure. Several studies have been completed to provide higher strength of the truss connections. However, the connection system is constrained by the costs of construction, availability of materials, equipment, skilled labored standardization. In this study, a connection system that possesses lightweight properties but with higher strength and lower cost while keeping the form of the bamboo being connected to remain natural has been developed. The proposed connection system consists of bolts, wooden gusset plates and special wooden clamps that have been adjusted with the shape and dimension of the bamboos being connected. A connection system without filler material on bamboo culms and wooden clamps used to increase the contribution to the shear at the connection has been proposed. The results showed an increase in the strength of the proposed connection of about 40% of the wood gusset plate system using wooden clamps than connection system without using wooden clamps, so it can be concluded that the proposed connection system possesses higher strength, yet much lower weight and has the potential for practical applications.

scholarly journals Engineering polymerases for applications in synthetic biology

2020 ◽  
Vol 53 ◽  
Author(s):  
Ali Nikoomanzar ◽  
Nicholas Chim ◽  
Eric J. Yik ◽  
John C. Chaput
Keyword(s):  
Cell Division ◽  
Synthetic Biology ◽  
Substrate Specificity ◽  
Physicochemical Properties ◽  
Genetic Information ◽  
Biomedical Applications ◽  
Dna Polymerases ◽  
Enzyme Engineering ◽  
Practical Applications ◽  
Naturally Occurring

Abstract DNA polymerases play a central role in biology by transferring genetic information from one generation to the next during cell division. Harnessing the power of these enzymes in the laboratory has fueled an increase in biomedical applications that involve the synthesis, amplification, and sequencing of DNA. However, the high substrate specificity exhibited by most naturally occurring DNA polymerases often precludes their use in practical applications that require modified substrates. Moving beyond natural genetic polymers requires sophisticated enzyme-engineering technologies that can be used to direct the evolution of engineered polymerases that function with tailor-made activities. Such efforts are expected to uniquely drive emerging applications in synthetic biology by enabling the synthesis, replication, and evolution of synthetic genetic polymers with new physicochemical properties.

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