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EN
The removal of Ni2+ from aqueous solution by magnetic multiwalled carbon nanotube nanocomposite (MMWCNTs-C) was investigated. MMWCNTs-C was characterized by X-ray Diffraction method (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), surface area (BET), and Fourier Transform-Infrared Spectroscopy (FTIR). The effects of initial concentration, contact time, solution pH, and temperature on the Ni2+ adsorption onto MMWCNTs-C were studied. The Langmuir and Freundlich isotherm models were applied to fit the adsorption data. The results showed that the adsorption isotherm data were fitted well to the Langmuir isotherm model with the maximum monolayer adsorption capacity of 2.11 mg g–1. The adsorption kinetics was best described by the pseudo-second-order model. The thermodynamic parameters, such as ΔHo, ΔGo and ΔSo, were also determined and evaluated. The adsorption of Ni2+ is generally spontaneous and thermodynamically favorable. The values of ΔHo and ΔGo indicate that the adsorption of Ni2+ onto MMWCNTs-C was a physisorption process.
EN
Multiwalled carbon nanotubes (MWCNTs) possess unique properties rendering them a potentially useful biomaterial for neurobiological applications such as providing nanoscale contact-guidance cues for directing axon growth within peripheral nerve repair scaffolds. The in vitro biocompatibility of MWCNTs with postnatal mouse spinal sensory neurons was assessed for this application. Cell culture medium conditioned with MWCNTs was not significantly toxic to dissociated cultures of postnatal mouse dorsal root ganglia (DRG) neurons. However, exposure of DRG neurons to MWCNTs dispersed in culture medium resulted in a time- and dose-dependent reduction in neuronal viability. At 250 μgmL−1, dispersed MWCNTs caused significant euronal death and unusual neurite morphologies illustrated by immunofluorescent labelling of the cytoskeletal protein beta (III) tubulin, however, at a dose of 5 μgmL−1 MWCNTs were nontoxic over a 14-day period. DRG neurons grown on fabricated MWCNT substrates produced neurite outgrowths with abnormal morphologies that were significantly inferior in length to neurons grown on the control substrate laminin. This evidence demonstrates that to be utilized as a biomaterial in tissue scaffolds for nerve repair, MWCNTs will require robust surface modification to enhance biocompatibility and growth promoting properties.
EN
The removal of Ni2+ from aqueous solution by magnetic multiwalled carbon nanotube nanocomposite (MMWCNTs-C) was investigated. MMWCNTs-C was characterized by X-ray Diffraction method (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), surface area (BET), and Fourier Transform-Infrared Spectroscopy (FTIR). The effects of initial concentration, contact time, solution pH, and temperature on the Ni2+ adsorption onto MMWCNTs-C were studied. The Langmuir and Freundlich isotherm models were applied to fit the adsorption data. The results showed that the adsorption isotherm data were fitted well to the Langmuir isotherm model with the maximum monolayer adsorption capacity of 2.11 mg g–1. The adsorption kinetics was best described by the pseudo-second-order model. The thermodynamic parameters, such as ΔHo, ΔGo and ΔSo, were also determined and evaluated. The adsorption of Ni2+ is generally spontaneous and thermodynamically favorable. The values of ΔHo and ΔGo indicate that the adsorption of Ni2+ onto MMWCNTs-C was a physisorption process.
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EN
In this work, research on influence of multiwalled carbon nanotubes (MWCNTs), produced in Catalic Chemical Carbon Vapor Deposition, NANOCYLTM NC7000CNTs on a structure and properties of AISI 301 steel remelted by TIG arc. In the assessment of influence a type of carbon on properties and structure of austenitic steel, as a carbon filler was use also carburizer. In the specimens (AISI 301 plates) with dimensions 155×60×7 [mm] were drilled holes with 1.3 mm diameter and placed 0.5 mm under specimen surface. Next, to the drilled holes was implemented CNTs, carburizer and mixture of these both powders. Prepared specimens were remelted by TIG method on the CASTOTIG 2200 power source with 2.4 mm tungsten thoriated electrode with parameters sets for obtain 3.0 mm penetration depth. Remelted specimens were cut into the half of the welds distance and prepared for metallographic examinations. Cross sections of the specimens were tested on classical metallography microscopes, hardness tests, SEM analyses (on JEOL 5800 LV SEM EDX equipment) and phase identification by X-ray phase analysis on Philips APD X’Pert PW 3020 diffractometer. Hardness analysis indicates about 25% increase of hardness in the remelted area when the CTNs are used. In the specimens with carburizer there is no significant changes. SEM analyses of remelted areas on AISI 301 specimens modificated with CNTs, indicates that dark areas, initially interpret as one of the phase (based on optical microscope) is finally densely packed bladders with dimensions from 50 nm up to a few µm. These bladders are not present in the specimens with carburizer filler. High resolution scanning microscopy allow to observe in the this area protruding, longitudinal particles with 100-300 nm length. For identification of this phase, X-ray analysis was done. But very small dimensions of used CNTs (diameters about 9,5 nm), random orientation and small weight amount can make difficult or impossible to CNTs detection during XRD tests. It means that it is not possible to clearly determine nature of particles filling the cavities, it is only possible to suppose that they are CNTs beams with nanoparticles comes from their disintegration. Results of the researches indicates, that fill in the weld pool with different form of carbon (CNTs and carburizer) it is possible to achieve remelted beads with different structure and hardness distribution. It confirms validity of the research continuation with CNTs as a modifier of steels and also other metals and theirs alloys.
EN
The paper investigates the possibility of using commercially available screen-printed sensors with carbon nanomaterials modified working electrodes to anodic stripping voltammetric determination of trace concentrations of Tl(I). Each working electrode was additionally plated in-situ with a bismuth film (BiF). The highest analytical signal of Tl(I) at potential of -0.65 V (vs. pseudo- reference silver electrode) was achieved at the screen-printed carbon sensor with multiwalled carbon nanotubes and bismuth film modified working electrode (SPCE/MWCNTs/BiF). The calibration curve was linear in the range of Tl(I) concentrations from 1·10-8 to 1·10-6 mol·dm-3 (-0.9 V, 180 s). The developed procedure of Tl(I) determination at this sensor allowed to achieve the low limits of detection and quantification of Tl(I), 2.8·10-9 and 9.3·10-9 mol·dm-3 respectively. The method was used to determine thallium in the spiked water samples from the Vistula river.
EN
Novel magnetic solid-phase extraction using carboxylated multiwalled carbon nanotubes was proposed with ultra high-performance liquid chromatography–tandem mass spectrometry for the determination of silodosin in biological samples. The effects of various experimental parameters including adsorbent amount, pH, adsorption time, desorption conditions, and adsorbent reusability were systematically validated. Under the optimized conditions, the calibration curve was linear within the concentration range of 1.0–800 ng mL−1 with the correlation coefficient of 0.9997 and the lower limit of detection was 0.3 ng mL−1. The extraction recoveries were over 90.0% with relative standard deviation (RSD) of less than 5.0%. All these results suggested that magnetic extraction method can be used for enrichment and quantification of silodosin in biological samples.
PL
W celu poprawy parametrów pojemnościowych wielościennych nanorurek węglowych (MWCNTs), wytworzonych metodą katalitycznego rozkładu acetylenu z wykorzystaniem stałego roztworu CoxMg(1-x)O, poddano je procesowi aktywacji chemicznej za pomocą KOH lub NaOH. W wyniku aktywacji z KOH, stosując moduł 4:1 uzyskano ponad dwukrotny wzrost powierzchni BET do 577 m2/g, głównie w zakresie mezoporowatym. Przyrost powierzchni mikroporowatej i dalszy wzrost powierzchni do 684 m2/g, uzyskano przy wyższym module KOH (5:1). W efekcie przeprowadzonych modyfikacji zanotowano istotną poprawę pojemności MWCNTs. Dla elektrod ujemnych w środowisku zasadowym sięga ona dwóch rzędów wielkości (77 F/g). Nie zaobserwowano prostej korelacji między zmianami strukturalnymi, a przyrostem pojemności, co wskazuje na istotny udział pseudopojemności. Aktywacja za pomocą NaOH, choć mniej efektywna (350 m2/g), pozwoliła uzyskać korzystną strukturę dla zastosowań w środowisku aprotycznym. MWCNTs, także po ich aktywacji, charakteryzuje wysoka dynamika wymiany ładunku, co predysponuje je na materiał elektrodowy dla kondensatorów dużej mocy.
EN
In order to improve capacitance parameters of multi-wall carbon nanotubes (MWCNTs) obtained by catalytic acethylene decomposition with solid solution of CoxMg(1-x)O, they were subject to activation process with KOH or NaOH. As a result of activation with KOH at 4:1 module, more than a double increase of BET surface to 577 m2/g was obtained, mainly in mesopore range. Higher microporous surface and further increase of BET surface to 684 m2/g was achieved at KOH (5:1) module. In consequence of such modifications, considerable improvement of MWCNTs capacitance was observed. For negative electrodes in alkaline environment , it reaches two order of magnitude higher value ( 77 F/g). No simple correlation between structural changes and capacitance increase was defined which, in turn, indicates considerable contribution of pseudocapacity. Activation with NaOH, although less efficient (350 m2/g), allowed to obtain advantageous structure for use in aprotic environment MWCNTs, also after activation, reveal high charge exchange dynamics and this feature makes them suitable as an electrode material for high power supercapacitors.
EN
Electrical characteristics of iron coated multi-walled carbon nanotubes (MWNTs) along with ferromagnetic properties are very interesting nanomaterial for microwave absorption. In this research work, surface morphology, compositions and microwave absorption properties of polymer containing iron coated MWNTs have been investigated. Iron coated multi-walled carbon nanotubes composite were prepared by two simple steps method. In addition, microstructure and microwave absorption properties under frequency range 8÷13 GHz by means of FESEM, EDX &Vector network analyzer had shown. The maximum reflection loss is observed for Fe-coated MWNTs/polymer sample B is –20.86 dB and –18.13 dB at frequency 8.1 and 10.75 GHz respectively. And the maximum bandwidth window is available for sample C is 3.25 GHz from frequency 8.45 to 11.7 GHz with 3 mm thickness, which can be attributed to synergistic effect of improved impedance matching characteristic and superior microwave attenuation characteristic of the absorber. The reflection properties of the material enhanced with variations in the wt.% of Fe-coated MWNTs and polymer. In this research paper, Fe-coated MWNTs are analyzed as promising microwave absorbing material and combined utilization of dielectric loss and magnetic loss absorbent design shows great design flexibility and diversity in the frequency range 8÷13 GHz.
EN
Electrospinning is an effective technique for fabricating submicron to nanoscale fibers from synthetic polymer as well as natural proteins. In this study, multiwalled carbon nanotubes (MWNTs) were embedded via electrospinning by adding MWNTs into the spinning dope, and found to be well aligned along the fiber axis in the silk fibroin nanofibers. The morphology and microstructure of the electrospun nanofibers were characterised using a field emission scanning electron microscope (FESEM) and Transmission electron microscopy (TEM). X-ray diffraction (XRD) and TG-DTA were used to study the crystal structure of the silk/MWNTs composite nanofibres, carried out to alter the strength, toughness and electrical conductivity of silk nanofibers by adding a small amount of MWNTs. The electrospun random silk mats with 1% MWNTs had a Young’s modulus, ultimate tensile strength and strain of 107.46 ± 9.15MPa, 9.94 ± 1.2MPa and 9.25 ± 1.5%, respectively, and electrical conductivity increased to 1.2×10-4S/cm. The silk/MWNTs composite nanofibres could potentially be applied in nerve repair materials owing to their excellent mechanical properties and electrical conductivity.
PL
Za pomocą elektroprzędzenia wytworzono jedwabne nanowłókna z dodatkiem nanorurek węglowych. Zbadano wpływ nanorurek węglowych na morfologię, strukturę, właściwości mechaniczne i przewodność elektryczną j nanowłókien. Morfologię i mikrostrukturę otrzymanych nanowłókien scharakteryzowano za pomocą skaningowego mikroskopu elektronowego (FESEM) i transmisyjnej mikroskopii elektronowej (TEM). Wyniki badań rentgenowskich i cieplnych wykazały, że dodanie nanorurek nie wywierało istotnego wpływu na strukturę nanowłókien w porównaniu do niemodyfikowanych nanowłókien fibroinowych. Poprzez dodanie nanorurek uzyskano polepszenie właściwości mechanicznych, została również polepszona przewodność elektryczna nanowłókien. Na podstawie otrzymanych wyników stwierdzono, że jedwabne nanowłókna z dodatkiem nanorurek węglowych mogą być stosowane w materiałach do naprawy nerwów dzięki ich doskonałym właściwościom mechanicznym i przewodności elektrycznej.
EN
A simple and convenient electrochemical method for direct determination of etharnbutol (EMB) using a glassy carbon electrode (GCE) modified with a film of multiwall carbon nanotubes (MWCNT) has been described. Electrochemical behavior of EMB has been investigated. Owing to the unique structure and extraordinary properties of MWCNT, the MWCNT film has shown an obvious electrocatalytic activity towards oxidation of EMB, since MWCNT greatly enhances the oxidation peak current of EMB and lowers its oxidation overpotential. All experimental parameters have been optimized. Under the optimum conditions the oxidation peak current was linearly proportional to the concentration of EMB in the range 8.0 x 10-6 to 2.5 x 10-4 mol L-1. The detection limit was 7.6 x 10-7 mol L-1 at 4 min accumulation, and the relative standard deviation (RSD) of eight determinations of 5 x 10-5 mol L-1 EMB was 4.1%. The proposed method has been successfully applied to the determination of EMB in drugs.
PL
Opisano prostą, wygodną metodę bezpośredniego oznaczania etambutolu (EMB) na elektrodach z węgla szklistego (GCE) modyfikowanych wielościennymi nanomrkami węglowymi (MWCNT). Zbadano elektrochemiczne zachowanie tego leku. Dzięki unikalnym właściwościom i strukturze MWCNT, modyfikowane GCE wykazywały aktywność elektrokatalityczną względem utleniania EMB (powiększenie prądu piku i obniżenie nadpotencjału). Zoptymalizowano parametry eksperymentalne pomiarów woltamperometrycznych. Prąd piku anodowego zależał liniowo od stężenia EMB w zakresie 8.0 x 10-6 to 2.5 x 10-4 mol L-1. Granica wykrywalności przy 4 min zatężaniu wynosiła 7.6 x 10-7 mol L-1, a względne odchylenie standardowe, obliczone z ośmiu pomiarów EMB o stężeniu 5 x 10-5 mol L-1 wynosiło 4,1%. Zaproponowanąmetodę z powodzeniem zastosowano do oznaczania EMB w lekach.
11
Content available remote Effect of MWCNTs content on the characteristics of A356 nanocomposite
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EN
Purpose: The objective of the present paper is to study the effect of Multiwalled Carbon Nanotubes (MWCNTs) content on the mechanical properties of the A356 hypoeutectic aluminum- silicon based nanocomposite. Design/methodology/approach: The semi-solid route stir casting technique is used for composite processing. MWCNTs and Aluminum powder are premixed by ball milling and green compacted to form small billets. Al-MWCNTs billets are added to the melt and incorporated by vigorous mechanical stirring. The mechanical and metallurgical properties of the produced composite are characterized by, scanning electron microscopy (SEM), optical microscopy, and tensile testing DIN 50125. Findings: MWCNTs are successfully incorporated into the A356 melt up to 1.5 % weight fraction. SEM analysis revealed a uniform dispersion of MWCNTs with good interfacial bonding between the matrix and the MWCNTs. The ultimate tensile strength and elongation of the produced composite are increased by 34% and 250% respectively compared to their corresponding values of monolithic alloy. Research limitations/implications: The research was carried out based on MWCNTs only with a range of percentage additions; it could be extended to single Walled CNTs and graphene sheets with different percentage additions. Stirring time and speed as well as heat treatment can also be applied as further study. Practical implications: This work helps in introducing novel technique in dispersing Nano particulates in metal matrix composites. This could be good potential for new developed composites. Originality/value: A novel approach for MWCNTs reinforcement addition technique is implemented. This technique results in a uniform dispersion of MWCNTs with good interfacial bonding between the matrix and the MWCNTs.
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