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نتیجه جستجو - Carbon nanotube

تعداد مقالات یافته شده: 38
ردیف عنوان نوع
1 Nanoinfiltration behavior of carbon nanotube based nanocomposites with enhanced mechanical and electrical properties
رفتار نانوفیلتراسیون نانوکامپوزیت های مبتنی بر نانولوله کربنی با خواص مکانیکی و الکتریکی بهبود یافته-2021
In this work, carbon nanotube (CNT) based nanocomposites with high mass fraction are proposed by in-situ bridging carbon matrix into CNT paper through optimized chemical vapor infiltration (CVI). Nanoinfiltration behavior of CNTs is basically investigated under the CVI process. The contact between each CNT can be strengthened and the conductive pathways can be established, resulting in the better mechanical and electrical properties. Compared with the pristine CNT paper, the CNT/C composite after pyrolysis process confirms a remarkable advance in tensile strength (up to 310 ± 13 MPa) and Young’s modulus (up to 2.4 ± 0.1 GPa). Besides, a notable feature of electrical conductivity also shows an improvement up to 8.5 S/cm, which can be attributed to the mass fraction of CNT (41 wt%) breaking the limits of percolation thresholds and the efficient densification of this sample to establish the conductive pathways. This study has a broad application in the development of the multi-functional electrical and engineering materials.
Keywords: Carbon nanotube | Chemical vapor infiltration (CVI) | Nanocomposites
مقاله انگلیسی
2 Mechanical properties and electrical resistivity of multiwall carbon nanotubes incorporated into high calcium fly ash geopolymer
Mechanical properties and electrical resistivity of multiwall carbon nanotubes incorporated into high calcium fly ash geopolymer-2021
High calcium fly ash (HCF) is a pozzolan material and is available in large quantity in Thailand due to the existence of coal-based electrical power plants. It is used as a supplemental material to partially replace cement content in concrete as a movement toward concrete sustainability. In order to lift the sustainability level, a cementitious material without Portland cement called ‘geopolymer’ was introduced. Geopolymer can be produced from raw materials containing high alumina and silica, for example fly ash, blast furnace slag, and metakaolin. For high calcium fly ash geopolymer (HCFG), the unique properties include fast setting, and high early strength. In this study, in order to enhance the properties of HCF geopolymer, multiwall carbon nanotubes (MWCNTs) were introduced into the matrix. In addition to the investigation into basic properties, the effect of MWCNT on electrical resistivity was also investigated to determine its potential use in piezoelectric sensor applications. The results showed that the addition of MWCNTs improved the mechanical properties of HCFG. The maximum compressive and flexural strengths were obtained with a mix containing 0.2% MWCNTs. The EDS test also indicated the increase in geopolymerization and hydration products with the addition of MWCNTs. To investigate the piezoelectricity potential, the electrical resistivity under different levels of compression loads was investigated. The resistivity decreased with the increasing load level up to the first crack, and then decreased. The changes in electrical resistivity indicated the potential use of HCFG incorporated MWCNTs in self-sensing for structural health monitoring.
Keywords: Geopolymer | High calcium fly ash | Multiwall carbon nanotube | Electrical resistivity
مقاله انگلیسی
3 Effect of CNT additives on the electrical properties of derived nanocomposites (experimentally and numerical investigation)
تأثیر افزودنی‌های CNT بر خواص الکتریکی نانوکامپوزیت‌های مشتق‌شده (بررسی تجربی و عددی)-2021
In this work, two simulations models have been developed to study the electrical percolation and the electrical conductivity of epoxy-based nanocomposite containing Multi-walled Carbon Nanotubes. The models are based on resistor-model and finite element analysis. The former was evaluated using MATLAB code and the finite element analysis using DIGIMAT software. The maximum tunneling distance and its influence on the percolation probability and final electrical conductivity were studied. Electrical measurements on the samples were conducted for numerical validation. The experimental data showed a percolation achievement around 2 wt%, which was confirmed in the numerical simulations. This study provides evidence of the effectiveness of the resistor model and finite element method approach to predict the electrical conductivity of nanocomposites.
Keywords: Polymer-matrix composites (PMCs) | Nanocomposites | Carbon nanotube | Electrical properties | Computational modelling
مقاله انگلیسی
4 Moisture dependence of electrical resistivity in under-percolated cement-based composites with multi-walled carbon nanotubes
وابستگی مقاومت الکتریکی به رطوبت در کامپوزیت های پایه سیمانی کم نفوذ با نانولوله های کربنی چند جداره-2021
Cement-based piezoresistive composites have attracted significant attention as smart construction materials for embedding self-sensing capability in concrete infrastructure. Although a number of studies have been conducted using multi-walled carbon nanotubes (MWCNTs) as a functional filler for self-sensing cement-based composites, studies addressing the influence of the internal moisture state on the electrical properties are relatively scant. In this study, we aim to experimentally investigate the effect of internal moisture state on the electrical resistivity of cement-based composites containing MWCNTs as an electrically conductive medium to raise a need for calibration of self-sensing data considering the internal moisture state. To this end, the moisture dependence of electrical resistivity in under-percolated cement-based composites was mainly evaluated, along with other material properties such as strength, shrinkage, and flowability. Results revealed that the electrical resistivity increased almost linearly as the internal relative humidity (IRH) decreased, and the increase was more pronounced below the percolation threshold. In addition, it was found that the strength gained by the microfiller effect of MWCNTs was significantly reduced particularly in under-percolated mixtures, leading to overall strength reductions. Furthermore, this study showed that the more the MWCNT was added, the smaller the flowability was obtained due to the increased viscosity of the mixture. The findings of this study are expected to provide pivotal information for accurate and reliable interpretations of self-sensing data generated by MWCNT-embedded cement-based composites.
Keywords: carbon nanotubes | cement-based composites | electrical resistivity | internal relative humidity | percolation threshold | self-sensing
مقاله انگلیسی
5 Definition of “b” exponent and development of power-law model for electrical conductivity of polymer carbon nanotubes nanocomposites
تعریف توان "b" و توسعه مدل قدرت قانون برای هدایت الکتریکی نانوکامپوزیت های نانولوله های کربن پلیمر-2020
In this article, the conventional power-law model for electrical conductivity of polymer carbon nanotubes (CNT) nanocomposites (PCNT) is linked with a developed model. The main goal is to define the “b” exponent and develop the power-law model for conductivity of PCNT. The interphase region surrounding nanoparticles and the CNT waviness, which affect the percolation threshold, the fraction of networked CNT and the effective volume fraction of CNT are taken into account. The developed model expresses that CNT concentration, CNT length and interphase thickness positively handle the conductivity of PCNT, while thick and waved CNT cause the adverse effect. Moreover, the calculations of the developed model accurately follow the experimental results of conductivity and “b” raises as CNT concentration increases.
Keywords: Polymer CNT nanocomposites | Electrical conductivity | Power-law model | Interphase region | Modeling
مقاله انگلیسی
6 Construction of various nanostructures on carbon nanotube films
ساخت انواع نانوساختارها بر روی فیلم های نانولوله کربنی-2020
Construction of nanostructures on surfaces has appealed intensive attention due to its significant applications in diverse fields. Especially, engineering surface properties via surficial nanostructures is actually the creation of functional interface-based materials and slated to be the key aspect for the future of materials science. Although many efforts have been made, there are only a few reports about the construction of nanostructures on carbon nanotube film surfaces. The big challenge for constructing on carbon films is that these carbon assemblies are easy to be dispersed by immersion in a chemical solution. Here, in this paper, we have shown for the first time the fabrication of different kinds of nanostructures, i.e. nanoneedles, nanoparticles, nanospirals, on carbon nanotube films by using facile and cheap electrodeposition method and precise physical deposition method. We pretreat the films by an electrical method to strengthen the films to avoid dispersion during the electrodeposition process. These composite films are still very flexible after coating with nanostructures. Compared with those precise physical deposition methods, the facile electrodeposition method is more suitable for constructing nanostructures on carbon nanotube films, due to the low requirement for planeness of films. It is interesting to find that these nanostructures can endow superhydrophobicity or higher conductivity for these flexible composite films, which greatly broaden the potential applications for carbon nanotube films in the fields of battery, moisture self-cleaning, electrostatic energy harvesting, and enhancing condensation heat transfer for more efficiency of energy utilization, environmental, and thermal management
Keywords: Arrays of nanostructures | Nano films | Superhydrophobicity | Environmental and energy management
مقاله انگلیسی
7 Characterisation and computational analysis of a novel lipase nanobio-based reagent for visualising latent fingerprints on water-immersed glass slides
خصوصیات و تجزیه و تحلیل محاسباتی یک معرف مبتنی بر نانو بیو لیپاز برای تجسم اثر انگشت نهان در اسلایدهای شیشه غوطه ور در آب-2020
Considering the significant evidential values of fingerprints in underwater criminal investigations and the need to visualise them using a user- and environmentally-friendly reagent, development of a novel, rapid and relatively greener nanobio-based reagent (NBR) is deemed beneficial. Lipase from the commercial Candida rugosa immobilised onto acid-functionalised multi-walled carbon nanotubes (NBR) was used as the safer and cheap lipid-sensing reagent to visualise groomed whole/split fingerprints on non-porous objects immersed in stagnant tap water for up to 30 days under a laboratory-controlled setting. Attenuated Total Reflectance – Fourier Transform Spectrometry, Field Emission Scanning Electron Microscopy and bioinformatics (molecular docking and molecular dynamics simulations) were employed to characterise and confirm the attachment of NBR onto the lipid constituents of wet fingerprints. Chromatographic results further confirmed the presence of n-hexadecanoic and octadecanoic acids on fingerprints up to 30 days of immersion. Thus, NBR may potentially be useful as the future state-of-the-art fingerprint visualisation technology.
Keywords: Latent fingerprint | Nanobio-based reagent | Candida rugosa lipase | Bioinformatics | Forensic science
مقاله انگلیسی
8 Application of the voltammetric electronic tongue based on nanocomposite modified electrodes for identifying rice wines of different geographical origins
کاربرد زبان الکترونیکی ولتامتری بر اساس الکترودهای اصلاح شده نانو کامپوزیت برای شناسایی شراب برنج با منشأ جغرافیایی مختلف-2019
In the study, the voltammetric electronic tongue based on three nanocomposites modified electrodes was applied for the identification of rice wines of different geographical origins. The nanocomposites were prepared by gold and copper nanoparticles in the presence of conducting polymers (polymer sulfanilic acid, polymer glutamic acid) and carboxylic multi - walled carbon nanotubes. The modified electrodes showed high sensitivity to guanosine - 5 - monophosphate disodium salt, tyrosine and gallic acid which have good correlation with the geographical origins of rice wines. Scanning electron microscopy was performed to display the surface morphologies of the nanocomposites, and cyclic voltammetry was applied to study the electrochemical behaviors of the taste substances on the electrode surfaces. Four types of electrochemical parameters (pH, scan rates, accumulation potentials and time) were optimized for getting a low limit of the detection of each taste substance. The geographical information of rice wines was obtained by the modified electrodes based on two types of multi - frequency large amplitude pulse voltammetry, and “area method” was applied for extracting the feature data from the original information obtained. Based on the area feature data, principal component analysis, locality preserving projection (LPP), and linear discriminant analysis were applied for the classification of the rice wines of different geographical origins, and LPP presented the best results; extreme learning machine (ELM) and alibrary for support vector machines were applied for predicting the geographical origins of rice wines, and ELM performed better.
Keywords: Nanocomposites modified electrodes | Conducting polymer | Multi - walled carbon nanotubes | Rice wine | Pattern recognition
مقاله انگلیسی
9 جذب ستونی از 2- نفتول برای محلول ابی با استفاده از جاذب کامپوزیتی مبتنی بر نانولوله کربنی
سال انتشار: 2018 - تعداد صفحات فایل pdf انگلیسی: 37 - تعداد صفحات فایل doc فارسی: 21
یک ساختار لایه هسته جاذب کامپوزیتی مبتنی بر نانولوله کربنی ساخته شده است و برای حذف 2- نفتول از محلول ابی در یک سیستم ستونی ثابت در این مطالعات پذیرفته شده است. اثری از پارامترهای عملیاتی شامل جرم جاذب، سرعت جریان نفوذی و غلظت ورودی در عملکرد جذب از ستون مورد بررسی قرار گرفته است. منحنی موفق دستابی شده نشان می دهد که در نگهداری موثر از 2- نفتول با استفاده از ستون جذب شده همراه جاذب کامپوزیتی مبتنی بر نانولوله کربنی بدست امده است. مقدار جذب تعادلی از 2- نفتول در جاذب کامپوزیتی مبتنی بر نانولوله کربنی از 122.7 میلی گرم بر کیلو گرم تا 286.6 میلی گرم بر کیلو گرم در این منطقه ازمایشگاهی متنوع است. افزایش جرم جاذب طول زمان موفقیت را افزایش می دهد و افزایش کل برداشت ها از ستون جاذب را افزایش می دهد. یک سرعت نفوذ بالاتر یا غلظت ورودی برای بهبود میزان جذب 2- نفتول در جاذب کامپوزیتی مبتنی بر نانولوله کربنی مفید است. رفتار دینامیکی از بسته های ستونی جاذب همراه جاذب کامپوزیتی مبتنی بر نانولوله کربنی با کمک مدل تامسون، مدل یان نلسون و مدل سرویس زمانی بد دیپ BDST توصیف شده است. سرویس زمانی از ستون برای وابستگی خطی برای عمق بستر یافت می شود. نتایجی از مطالعات نشان می دهد که جاذب کامپوزیتی مبتنی بر نانولوله کربنی می تواند در ستون بستر ثابت برای حذف موثر 2-نفتول از اب بکار برده شود.
کلمات کلیدی: جذب | نانولوله کربنی (CNT) | جاذب کامپوزیت | بستر ثابت ستون | مدل سازی | نفتول
مقاله ترجمه شده
10 ارزیابی اثر حلال در برهمکنش داروی کارموستین همراه نانولوله تک دیواره اولیه و بهینه شده با COOH : یک چشم اندازی از تئوری تابع چگالی
سال انتشار: 2017 - تعداد صفحات فایل pdf انگلیسی: 35 - تعداد صفحات فایل doc فارسی: 27
رفتار جذبی داروی کارموستین در سطح نانولوله تک دیواره اولیه (5.5) و نانولوله تک دیواره بهینه شده همراه یک گروه کربوکسیلیک اسید به کمک محاسبات DFT بررسی شد. برای مطالعه هر دو نانولوله ، اثر جهت گیری مولکول ها در انرژی جذبی ، ساختار مولکولی، فاصله تعادلی و توصیف کوانتوم مولکولی مورد مطالعه قرار گرفت. بر طبق نتایج بدست امده، فرایند جذب کارموستین در سطح خارجی نانولوله عامل دار گرمازا است و تمام صورتبندی های عامل دار پایدار است، در حالی که فرایند جذب دارو در سطح خارجی نانولوله اولیه گرماگیر است و ساختار جذبی ناپایدار است. بعد از ان یافت شدکه برهمکنش پیوند هیدروژن بین مولکولی بین کارمستین و نانولوله بهینه شده نقش زیادی در پایداری جذب فیزیکی صورتبندی بازی می کند. بنابراین انرژی پایداری منفی به وسیله یک مدل قطبش پذیر پیوسته نشان می دهد که افزایش در حلالیت نانولوله بعد از جذب دارو در سطح در محلول اب حاضر صورت می گیرد. برهمکنش های بین مولکولی به وسیله محاسبات دانسیته الکترونی و لاپلاسین در نقاط بحرانی پیوند با استفاده از نظریه اتم در مولکول توضیح داده شد. انالیز اربیتال پیوند طبیعی نشان داد که مولکول کارمستین می توان جذب سطح نانولوله همراه با انتقال بار از نانولوله به مولکول دارو شود.
کلمات کلیدی: جذب دارو | روش DFT | AIM | NBO | SWCNT | f-SWCNT
مقاله ترجمه شده
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