scholarly journals Fabrication of carbon nanotube-reinforced mortar specimens: evaluation of mechanical and pressure-sensitive properties

2018 ◽  
Vol 188 ◽  
pp. 01019 ◽  
Author(s):  
Evangelia K. Karaxi ◽  
Irene A. Kanellopoulou ◽  
Anna Karatza ◽  
Ioannis A. Kartsonakis ◽  
Costas A. Charitidis
Keyword(s):  
Cementitious Composites ◽  
Mixing Process ◽  
Mechanical And Electrical Properties ◽  
Pressure Sensitive ◽  
Polar Media ◽  
Significant Research ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

Carbon-based nanomaterials are promising reinforcing elements for the development of “smart” self-sensing cementitious composites due to their exceptional mechanical and electrical properties. Significant research efforts have been committed on the synthesis of cement-based composite materials reinforced with carbonaceous nanostructures, covering every aspect of the production process (type of nanomaterial, mixing process, electrode type, measurement methods etc.). In this study, the aim is to develop a well-defined repeatable procedure for the fabrication as well as the evaluation of pressure-sensitive properties of intrinsically self-sensing cementitious composites incorporating carbon- based nanomaterials. Highly functionalized multi-walled carbon nanotubes with increased dispersibility in polar media were used in the development of advanced reinforced mortar specimens which increased their mechanical properties and provided repeatable pressure-sensitive properties.

scholarly journals Carbon-Based Nanomaterials Increase Reactivity of Primary Monocytes towards Various Bacteria and Modulate Their Differentiation into Macrophages

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2510
Author(s):  
Tereza Svadlakova ◽  
Martina Kolackova ◽  
Radka Vankova ◽  
Rumeysa Karakale ◽  
Andrea Malkova ◽  
...  
Keyword(s):  
Proinflammatory Response ◽  
Cell Functions ◽  
Tnf Α ◽  
Additional Cell ◽  
Direct Cytotoxicity ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Based Nanomaterials ◽  
Factor Α ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

The evaluation of carbon-based nanomaterials’ (C-BNMs’) interactions with the immune system, notably their ability to cause inflammation, is a critical step in C-BNM health risk assessment. Particular attention should be given to those C-BNMs that do not cause direct cytotoxicity or inflammation on their own. However, the intracellular presence of these non-biodegradable nanomaterials could dysregulate additional cell functions. This is even more crucial in the case of phagocytes, which are the main mediators of defensive inflammation towards pathogens. Hence, our study was focused on multi-walled carbon nanotubes (MWCNTs) and two different types of graphene platelets (GPs) and whether their intracellular presence modulates a proinflammatory response from human primary monocytes towards common pathogens. Firstly, we confirmed that all tested C-BNMs caused neither direct cytotoxicity nor the release of tumour necrosis factor α (TNF-α), interleukin (IL)-6 or IL-10. However, such pre-exposed monocytes showed increased responsiveness to additional bacterial stimuli. In response to several types of bacteria, monocytes pre-treated with GP1 produced a significantly higher quantity of TNF-α, IL-6 and IL-10. Monocytes pre-treated with MWCNTs produced increased levels of IL-10. All the tested C-BNMs enhanced monocyte phagocytosis and accelerated their differentiation towards macrophages. This study confirms the immunomodulatory potential of C-BNMs.

Thermal Conductivity of Colloidal Suspensions of Jet Fuel and Carbon-Based Nanoparticles and its Effect on Evaporation Rate

2018 ◽  
Author(s):  
Mohsen Ghamari ◽  
Ahmed Aboalhamayie
Keyword(s):  
Thermal Conductivity ◽  
Burning Rate ◽  
Evaporation Rate ◽  
Colloidal Suspensions ◽  
Jet Fuel ◽  
Liquid Fuels ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

Recent studies have shown that addition of nano-sized particles to liquid fuels could significantly enhance major combustion characteristics such as burning rate and ignition delay. Colloidal suspensions are known to have enhanced optical properties and thermal conductivity compared to neat liquids; however, in the case of colloidal fuels, the main mechanism responsible for such enhanced properties is not well understood. To better understand these phenomena, colloidal suspensions of jet fuel and different types of carbon-based nanomaterials (carbon nanoparticles, multi-walled carbon nanotubes, and graphene nanoplatelets) prepared at different particle loadings were experimentally tested for their thermal conductivities. Colloidal suspensions of nanotubes showed higher conductivity compared to that of graphene and nanoparticle. This could justify higher burning rate of these fuels. Furthermore, and to differentiate between the effects of thermal conduction and radiation, droplet evaporations tests were carried out on colloidal suspensions of carbon nanoparticle under forced convection and in the absence of any radiation source. It was found that the presence of nanoparticle in jet fuel initially increases evaporation rate. However, a reduction in evaporation rate was observed at higher concentration as a result of particles agglomeration.

scholarly journals Carbon-Based Nanomaterials in Sensors for Food Safety

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1330 ◽  
Author(s):  
Mingfei Pan ◽  
Zongjia Yin ◽  
Kaixin Liu ◽  
Xiaoling Du ◽  
Huilin Liu ◽  
...  
Keyword(s):  
Food Safety ◽  
High Performance ◽  
Carbon Quantum Dots ◽  
Detection Accuracy ◽  
Signal Conversion ◽  
Multi Walled Carbon Nanotubes ◽  
And Performance ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

Food safety is one of the most important and widespread research topics worldwide. The development of relevant analytical methods or devices for detection of unsafe factors in foods is necessary to ensure food safety and an important aspect of the studies of food safety. In recent years, developing high-performance sensors used for food safety analysis has made remarkable progress. The combination of carbon-based nanomaterials with excellent properties is a specific type of sensor for enhancing the signal conversion and thus improving detection accuracy and sensitivity, thus reaching unprecedented levels and having good application potential. This review describes the roles and contributions of typical carbon-based nanomaterials, such as mesoporous carbon, single- or multi-walled carbon nanotubes, graphene and carbon quantum dots, in the construction and performance improvement of various chemo- and biosensors for various signals. Additionally, this review focuses on the progress of applications of this type of sensor in food safety inspection, especially for the analysis and detection of all types of toxic and harmful substances in foods.

scholarly journals Stabilizing effect of methylcellulose on the dispersion of multi-walled carbon nanotubes in cementitious composites

2020 ◽  
Vol 9 (1) ◽  
pp. 93-104
Author(s):  
Mingrui Du ◽  
Yuan Gao ◽  
Guansheng Han ◽  
Luan Li ◽  
Hongwen Jing
Keyword(s):  
Carbon Nanotubes ◽  
Pore Solution ◽  
Cementitious Materials ◽  
High Ionic Strength ◽  
Cementitious Composites ◽  
Uniform Distributions ◽  
Stabilizing Effect ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes

AbstractMulti-walled carbon nanotubes (MWCNTs) have been added in the plain cementitious materials to manufacture composites with the higher mechanical properties and smart behavior. The uniform distributions of MWCNTs is critical to obtain the desired enhancing effect, which, however, is challenged by the high ionic strength of the cement pore solution. Here, the effects of methylcellulose (MC) on stabilizing the dispersion of MWCNTs in the simulated cement pore solution and the viscosity of MWCNT suspensions werestudied. Further observations on the distributions of MWCNTs in the ternary cementitious composites were conducted. The results showed that MC forms a membranous envelope surrounding MWCNTs, which inhibits the adsorption of cations and maintains the steric repulsion between MWCNTs; thus, the stability of MWCNT dispersion in cement-based composites is improved. MC can also work as a viscosity adjuster that retards the Brownian mobility of MWCNTs, reducing their re-agglomerate within a period. MC with an addition ratio of 0.018 wt.% is suggested to achieve the optimum dispersion stabilizing effect. The findings here provide a way for stabilizing the other dispersed nano-additives in the cementitious composites.

scholarly journals Accelerated Shape Forming and Recovering, Induction, and Release of Adhesiveness of Conductive Carbon Nanotube/Epoxy Composites by Joule Heating

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1030 ◽  
Author(s):  
Petr Slobodian ◽  
Pavel Riha ◽  
Robert Olejnik ◽  
Jiri Matyas
Keyword(s):  
Carbon Nanotube ◽  
Joule Heating ◽  
Adhesive Bonding ◽  
Recovery Process ◽  
Epoxy Adhesive ◽  
Porous Network ◽  
Mechanical And Electrical Properties ◽  
Multi Walled Carbon Nanotubes ◽  
Dc Current ◽  
Walled Carbon Nanotubes

The versatile properties of a nanopaper consisting of a porous network of multi-walled carbon nanotubes were applied to enhance the mechanical and electrical properties of a thermosetting epoxy polymer. The embedded nanopaper proved useful both in the monitoring of the curing process of the epoxy resin by the self-regulating Joule heating and in the supervising of tensile deformations of the composite by detecting changes in its electrical resistance. When heated by Joule heating above its glass transition temperature, the embedded carbon nanotube nanopaper accelerated not only the modelling of the composites into various shapes, but also the shape recovery process, wherein the stress in the nanopaper was released and the shape of the composite reverted to its original configuration. Lastly, in comparison with its respective epoxy adhesive, the internally heated electro-conductive carbon nanotube nanopaper/epoxy composite not only substantially shortened curing time while retaining comparable strength of the adhesive bonding of the steel surfaces, but also enabled a release of such bonds by repeated application of DC current.

scholarly journals Spermatotoxic Effects of Single-Walled and Multi-Walled Carbon Nanotubes on Male Mice

2020 ◽  
Vol 7 ◽  
Author(s):  
Omid Farshad ◽  
Reza Heidari ◽  
Mohammad Javad Zamiri ◽  
Socorro Retana-Márquez ◽  
Meghdad Khalili ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Carbon Nanotubes ◽  
Sperm Count ◽  
Weight Coefficient ◽  
Reproductive Organs ◽  
Significant Decrement ◽  
Total Antioxidant ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes

Carbon-based nanomaterials possess a remarkably high potential for biomedical applications due to their physical properties; however, their detrimental effects on reproduction are also concerned. Several reports indicate the toxicity of carbon nanotubes (CNT); nevertheless, their impact on intracellular organelles in the male reproductive organs has not been fully elucidated. Herein, we report on the reprotoxicity of single-walled (SWCNT) and multi-walled carbon nanotubes (MWCN) on several intracellular events and histological criteria in pubertal male BALB/c mice orally treated with 0, 10, and 50 mg/kg/day doses for 5 weeks. Biomarkers of oxidative stress and mitochondrial functionality, histopathological alterations, and epididymal sperm characteristics were determined. Oral administration of CNTs at 10 and 50 mg/kg evoked a significant decrement in weight coefficient, sperm viability and motility, hypo-osmotic swelling (HOS) test, sperm count, mitochondrial dehydrogenase activity, ATP content, total antioxidant capacity, and GSH/GSSH ratio in the testis and epididymal spermatozoa. On the other hand, percent abnormal sperm, testicular and sperm TBARS contents, protein carbonylation, ROS formation, oxidized glutathione level, and sperm mitochondrial depolarization were considerably increased. Significant histopathological and stereological alterations in the testis occurred in the groups challenged with CNTs. The current findings indicated that oxidative stress and mitochondrial impairment might substantially impact CNTs-induced reproductive system injury and sperm toxicity. The results can also be used to establish environmental standards for CNT consumption by mammals, produce new chemicals for controlling the rodent populations, and develop therapeutic approaches against CNTs-associated reproductive anomalies in the males exposed daily to these nanoparticles.

Carbon-Based Nanomaterials for Drugs Sensing: A Review

2014 ◽  
Vol 807 ◽  
pp. 13-39
Author(s):  
Bavani Kasinathan ◽  
Ruzniza Mohd Zawawi
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Carbon Nanofibers ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Sensing Applications ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

Carbon-based nanomaterials such as graphene, carbon nanotubes, carbon nanofibers and nanodiamonds have been fascinated considerable attention as promising materials for drug sensing. These materials have tremendous amount of attraction due to some extraordinary features such as excellent electrical and thermal conductivities as well as high mechanical strength. Hence, these nanomaterials have been used extensively in sensor technology in order to achieved desired sensitivities. To date, carbon based nanomaterials have been exploit in the development of various drug sensing due to their simple preparation methods, and cost effectiveness. The aim of this review is to focus upon carbon based nanomaterials predominantly on drugs sensing applications. This review has been written in summary form including properties, fabrication method, and analytical performances.Abbreviation:Au, Gold; CNFs, Carbon Nanofibers; CNTs, Carbon Nanotubes; CVD, Chemical Vapour Deposition; D-, Dextrorotatory enantiomer; D, Dimensional; DNase, deoxyribonuclease; ESD, Electrospinning deposition; GCE, Glassy Carbon Electrode; Gr, Graphene; GrO, Graphene Oxide; ILs, ionic liquids; L-, Levorotatory enantiomer; LOD, Limit of Detection; MTase, Methyltransferases; MW, Microwave; MWCNTs, Multi-walled Carbon nanotubes; NDs, Nanodiamonds; NPs, Nanoparticles; PECVD, Plasma Enhanced Chemical Vapour Deposition; RGO, Reduced Graphene Oxide; SPE, Screen-Printed Electrode; SPR, Surface Plasmon resonance; ssDNA, single-stranded DNA; SWCNTs, Single-walled Carbon nanotubes.

Sign in / Sign up

Export Citation Format

Share Document