scholarly journals Engineering of oriented carbon nanotubes in composite materials

2018 ◽  
Vol 9 ◽  
pp. 415-435 ◽  
Author(s):  
Razieh Beigmoradi ◽  
Abdolreza Samimi ◽  
Davod Mohebbi-Kalhori
Keyword(s):  
Carbon Nanotubes ◽  
Composite Materials ◽  
Composite Structures ◽  
Recent Progress ◽  
Ex Situ ◽  
Random Orientation ◽  
Advantages And Disadvantages ◽  
Device Integration ◽  
Growth Restrictions

The orientation and arrangement engineering of carbon nanotubes (CNTs) in composite structures is considered a challenging issue. In this regard, two groups of in situ and ex situ techniques have been developed. In the first, the arrangement is achieved during CNT growth, while in the latter, the CNTs are initially grown in random orientation and the arrangement is then achieved during the device integration process. As the ex situ techniques are free from growth restrictions and more flexible in terms of controlling the alignment and sorting of the CNTs, they are considered by some as the preferred technique for engineering of oriented CNTs. This review focuses on recent progress in the improvement of the orientation and alignment of CNTs in composite materials. Moreover, the advantages and disadvantages of the processes are discussed as well as their future outlook.

scholarly journals Collecting eco-evolutionary data in the dark: Impediments to subterranean research and how to overcome them

2020 ◽  
Author(s):  
Stefano Mammola ◽  
Enrico Lunghi ◽  
Helena Bilandžija ◽  
Pedro Cardoso ◽  
Volker Grimm ◽  
...  
Keyword(s):  
Model Systems ◽  
Ex Situ ◽  
Model Organisms ◽  
Physiological Tolerance ◽  
Advantages And Disadvantages ◽  
General Scientific ◽  
Experimental Model Systems ◽  
Scientific Questions ◽  
Subterranean Species

(1) Caves and other subterranean habitats fulfill the requirements of experimental model systems to address general questions in ecology and evolution. Yet, the harsh working conditions of these environments and the uniqueness of the subterranean organisms have challenged most attempts to pursuit standardized research(2) Two main obstacles have synergistically hampered previous attempts. First, there is a habitat impediment related to the objective difficulties of exploring subterranean habitats and our inability to access the network of fissures that represent the elective habitat for the so-called “cave species.” Second, there is a biological impediment illustrated by the rarity of most subterranean species and their low physiological tolerance, often limiting sample size and complicating lab experiments.(3) We explore the advantages and disadvantages of four general experimental setups (in-situ, quasi in-situ, ex-situ, and in-silico) in the light of habitat and biological impediments. We also discuss the potential of indirect approaches to research. Furthermore, using bibliometric data, we provide a quantitative overview of the model organisms that scientists have exploited in the study of subterranean life.(4) Our over-arching goal is to promote caves as model systems where one can perform standardised scientific research. This is important not only to achieve an in-depth understanding of the functioning of subterranean ecosystems but also to fully exploit their long-discussed potential in addressing general scientific questions with implications beyond the boundaries of this discipline.

scholarly journals Soil Bioremediation: Overview of Technologies and Trends

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4664
Author(s):  
Israel Gonçalves Sales da Silva ◽  
Fabíola Carolina Gomes de Almeida ◽  
Nathália Maria Padilha da Rocha e Silva ◽  
Alessandro Alberto Casazza ◽  
Attilio Converti ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Petroleum Hydrocarbons ◽  
Ex Situ ◽  
Soil Bioremediation ◽  
Application Of Surfactants ◽  
Agricultural Pesticides ◽  
Advantages And Disadvantages ◽  
Microbiological Characteristics ◽  
Extent Of Damage

Petroleum hydrocarbons, heavy metals and agricultural pesticides have mutagenic, carcinogenic, immunotoxic and teratogenic effects and cause drastic changes in soil physicochemical and microbiological characteristics, thereby representing a serious danger to health and environment. Therefore, soil pollution urgently requires the application of a series of physicochemical and biological techniques and treatments to minimize the extent of damage. Among them, bioremediation has been shown to be an alternative that can offer an economically viable way to restore polluted areas. Due to the difficulty in choosing the best bioremediation technique for each type of pollutant and the paucity of literature on soil bioremediation enhanced by the use of specific additives, we reviewed the main in situ and ex situ methods, their current properties and applications. The first section discusses the characteristics of each class of pollutants in detail, while the second section presents current bioremediation technologies and their main uses, followed by a comparative analysis showing their respective advantages and disadvantages. Finally, we address the application of surfactants and biosurfactants as well as the main trends in the bioremediation of contaminated soils.

In-Situ Characterization of Carbon Nanotube-Polystyrene Composite Deformation

2000 ◽  
Vol 6 (S2) ◽  
pp. 40-41
Author(s):  
D. Qian ◽  
E. C. Dickey ◽  
R. Andrews ◽  
T. Rantell ◽  
B. Safadi
Keyword(s):  
Carbon Nanotubes ◽  
Load Transfer ◽  
Electronic Materials ◽  
Composite Films ◽  
Chemical Vapor ◽  
Ex Situ ◽  
In Situ Tem ◽  
Multiwalled Carbon ◽  
Young’S Moduli

Carbon nanotubes (NTs) have novel electronic properties and exceptionally high Young's moduli on the order of TPa. so NTs have potential applications in advanced composite materials such as conductive polymers, electromagnetic-radio frequency interference (EMI/RFI) shielding material and opto-electronic materials. The utility of the nanotubes in composite applications depends strongly on the ability to disperse the NTs homogeneously throughout the matrix without destroying the integrity of the NTs. Furthermore, interfacial bonding between the NT and matrix is necessary to achieve load transfer across the interface, which is desirable for improving the mechanical properties of polymer composites.In this work, aligned multiwalled carbon nanotubes (MWNTs) produced by continuous chemical vapor deposition (CVD) (see Fig.l), were homogeneously dispersed in polystyrene (PS) matrices by a simple solution-evaporation method. Using this procedure, we made uniform MWNT-PS composite films ∼0.4mm thick for ex-situ mechanical tensile test and very thin films, ∼100nm, for in-situ TEM tests, as shown in Fig.2.

scholarly journals Computer-Controlled Polishing System For Preparing Multiple Pre-FIB TEM Specimens

2007 ◽  
Vol 15 (6) ◽  
pp. 38-39
Author(s):  
D. J. MacMahon ◽  
E. Raz-Moyal
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Product Yield ◽  
Interface Layer ◽  
Ex Situ ◽  
Advantages And Disadvantages ◽  
Transmission Electron ◽  
Invaluable Tool ◽  
Electron Microscopes

Semiconductor manufacturers are increasingly turning to Transmission Electron Microscopes (TEMs) to monitor product yield and process control, analyze defects, and investigate interface layer morphology. To prepare TEM specimens, Focused Ion Beam (FIB) technology is an invaluable tool, yielding a standard milled TEM lamella approximately 15 μm wide, 5 μm deep and ~100 nm thick. Several techniques have been developed to extract these tiny objects from a large wafer and view it in the TEM. These techniques, including ex-situ lift-out, H-bar, and in-situ lift-out, have different advantages and disadvantages, but all require painstaking preparation of one specimen at a time.

scholarly journals A Review on Micro-Patterning Processes of Vertically Aligned Carbon Nanotubes Array (VACNTs Array)

2019 ◽  
Vol 15 (4) ◽  
pp. 328-353 ◽  
Author(s):  
Mohd Asyraf Bin Mohd Razib ◽  
Tanveer Saleh
Keyword(s):  
Carbon Nanotubes ◽  
Angle Sensor ◽  
Micro Electro Mechanical Systems ◽  
Vertically Aligned Carbon Nanotubes ◽  
Advantages And Disadvantages ◽  
Micro Patterning ◽  
Aligned Carbon Nanotubes ◽  
Vertically Aligned ◽  
Different Characteristics

Vertically Aligned Carbon Nanotubes array which is also sometimes labeled as carbon nanotubes forests has many applications in several engineering fields for its remarkable mechanical, electrical, optical, and thermal properties. The Vertically Aligned Carbon Nanotubes array is often employed in developing microdevices such as pressure sensor, angle sensor, switches, etc. To successfully integrate carbon nanotubes forest to the micro-electro-mechanical systems based devices, micropatterning of the carbon nanotubes forest is required. There are several methods available to realize micropatterning of Vertically Aligned Carbon Nanotubes array, from in-situ patterning during the growth process to post-patterning process. Each has its advantages and disadvantages. This paper will discuss elaborately different patterning processes of the carbon nanotubes forest and their different characteristics.

scholarly journals Preparation of Composite Materials Containing Polyethylene and Carbon Nanotubes by in situ Ethylene Polymerization over Titanium-Magnesium Catalyst Fixed on the Surface of Carbon Nanotubes

2020 ◽  
pp. 033-042
Author(s):  
A.A. Zdanovich ◽  
◽  
M.A. Matsko ◽  
A.V. Melezhik ◽  
A.G. Tkachev ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Composite Materials ◽  
Ethylene Polymerization ◽  
In Situ Polymerization ◽  
Organomagnesium Compound ◽  
Mwcnt Surface ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Different Molecular Weight

The data on the preparation of composite materials containing polyethylene and multi-walled carbon nanotubes (MWCNTs) of the Taunit brand are presented. To obtain these composites by in situ polymerization, a catalytic system formed by the interaction of an organomagnesium compound and TiCl4 on the surface of nanotubes was used. The catalyst fixed on the MWCNT surface has a high activity in ethylene polymerization and allows to obtain a polymer with different molecular weight. The data on the formation of a polymer on the MWCNT surface and the morphology of composites formed on various Taunit samples are presented.

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