Abstract: Carbon nanotubes (CNTs) are known for having high elastic properties with high surface area that promote them as good candidates for reinforcing polymeric matrices. In composite materials, CNTs lack chemical bonding with the surrounding matrix which decreases the possibility of better stress transfer between the components. In this work, a chemical treatment for activating the surface of the multi-wall carbon nanotubes (MWCNT) was applied and the effect of this functionalization on the elastic properties of the epoxy nanocomposites was studied. Functional amino-groups were added to the surface of the CNTs and it was evaluated to be about 34% of the total weight of the CNTs. Elastic modulus was found to increase by about 40% of the neat epoxy resin at CNTs’ weight fraction of 0.5%. The elastic modulus was found to decrease after reaching a certain concentration of CNTs which was found to be 1% wt. The scanning electron microscopic pictures showed the effect of the CNTs on the crack propagation through the sample by forming stress concentrated spots at the nanocomposite samples.
Abstract: To tackle the air pollution issues, Plug-in Hybrid
Electric Vehicles (PHEVs) are proposed as an appropriate solution.
Charging a large amount of PHEV batteries, if not controlled, would
have negative impacts on the distribution system. The control process
of charging of these vehicles can be centralized in parking lots that
may provide a chance for better coordination than the individual
charging in houses. In this paper, an optimization-based approach is
proposed to determine the optimum PHEV parking capacities in
candidate nodes of the distribution system. In so doing, a profile for
charging and discharging of PHEVs is developed in order to flatten
the network load profile. Then, this profile is used in solving an
optimization problem to minimize the distribution system losses. The
outputs of the proposed method are the proper place for PHEV
parking lots and optimum capacity for each parking. The application
of the proposed method on the IEEE-34 node test feeder verifies the
effectiveness of the method.
Abstract: Nanotechnology has become the world attention in
various applications including the solar cells devices due to the
uniqueness and benefits of achieving low cost and better
performances of devices. Recently, thin film solar cells such as
Cadmium Telluride (CdTe), Copper-Indium-Gallium-diSelenide
(CIGS), Copper-Zinc-Tin-Sulphide (CZTS), and Dye-Sensitized
Solar Cells (DSSC) enhanced by nanotechnology have attracted
much attention. Thus, a compilation of nanotechnology devices
giving the progress in the solar cells has been presented. It is much
related to nanoparticles or nanocrystallines, carbon nanotubes, and
nanowires or nanorods structures.
Abstract: The Chair of Thermal Engineering at Poznan
University of Technology has been conducted research works on the
possibilities of using carbon nanostructures in energy and mechanics
applications for a couple of years. Those studies have provided results in a form of co-operation with foreign research centres, numerous publications and patent
applications.
Authors of this paper have studied the influence of multi-walled
carbon nanostructures on changes in static friction arising when steel
surfaces were moved. Tests were made using the original test stand
consisting of automatically controlled inclined plane driven by
precise stepper motors. Computer program created in the LabView
environment was responsible for monitoring of the stand operation,
accuracy of measurements and archiving the obtained results. Such a
solution enabled to obtain high accuracy and repeatability of all
conducted experiments.
Tests and analysis of the obtained results allowed us to determine
how additional layers of carbon nanostructures influenced on changes
of static friction coefficients. At the same time, we analyzed the
potential possibilities of applying nanostructures under consideration
in mechanics.
Abstract: We report herein the development and preliminary mechanical characterization of fully-dense multi-wall carbon nanotube (MWCNT)-reinforced ceramics and glasses based on a completely new methodology termed High Shear Compaction (HSC). The tubes are introduced and bound to the matrix grains by aid of polymeric binders to form flexible green bodies which are sintered and densified by spark plasma sintering to unprecedentedly high densities of 100% of the pure-matrix value. The strategy was validated across a PyrexTM glass / MWCNT composite while no identifiable factors limit application to other types of matrices. Nondestructive evaluation, based on ultrasonics, of the dynamic mechanical properties of the materials including elastic, shear and bulk modulus as well as Poisson’s ratio showed optimum property improvement at 0.5 %wt tube loading while evidence of nanoscalespecific energy dissipative characteristics acting complementary to nanotube bridging and pull-out indicate a high potential in a wide range of reinforcing and multifunctional applications.
Abstract: Doxorubicin (DOX) is an anthracycline drug used to treat many cancer diseases. Similarly to other cytostatic drugs, DOX has serious side effects; the biggest obstacle is the cardiotoxicity. With the aim of lowering the negative side effects and to target the DOX into the tumor tissue, the different nanoparticles (NPs) are studied. The aim of this work was to synthetized different NPs and conjugated them with DOX and determine the binding capacity of the NPs. For this experiment, carbon nanotubes (CNTs), graphene oxide (GO), fullerene (FUL) and liposomes (LIP) were used. The highest binding capacity was observed in GO (85%). Subsequently the toxicity of NPs and NPs-DOX conjugates was analyzed in in vivo system (chicken embryos). Some NPs (GO) can increase the toxicity of DOX, whereas other NPs (LIP, CNTs) decrease DOX toxicity.
Abstract: In the present work, the dielectric properties of
Epoxy/MWCNT-muscovite HYBRID and MIXED composites based
on a ratio 30:70 were studied. The multi-wall carbon nanotubes
(MWCNT) were prepared using two methods: (a) MWCNTmuscovite
hybrids were synthesised by chemical vapour deposition
(CVD) and (b) physically mixing muscovite with MWCNT. The
effects of different preparation of the composites and filler loading
were evaluated. It was revealed that the dielectric constants of
HYBRID epoxy composites are slightly higher than MIXED epoxy
composites. It was also indicated that the dielectric constant increased
by increasing the MWCNT filler loading.
Abstract: Considering palm oil as non-drying oil owing to its
low iodine value, an attempt was taken to increase the unsaturation in
the fatty acid chains of palm oil for the preparation of alkyds. To
increase the unsaturation in the palm oil, sulphuric acid (SA) and
para-toluene sulphonic acid (PTSA) was used prior to alcoholysis for
the dehydration process. The iodine number of the oil samples was
checked for the unsaturation measurement by Wijs method. Alkyd
resin was prepared using the dehydrated palm oil by following
alcoholysis and esterification reaction. To improve the film properties
0.5wt.% multi-wall carbon nano tubes (MWCNTs) were used to
manufacture polymeric film. The properties of the resins were
characterized by various physico-chemical properties such as density,
viscosity, iodine value, saponification value, etc. Structural
elucidation was confirmed by Fourier transform of infrared
spectroscopy and proton nuclear magnetic resonance; surfaces of the
films were examined by field-emission scanning electron microscope.
In addition, pencil hardness and chemical resistivity was also
measured by using standard methods. The effect of enhancement of
the unsaturation in the fatty acid chain found significant and
motivational. The resin prepared with dehydrated palm oil showed
improved properties regarding hardness and chemical resistivity
testing. The incorporation of MWCNTs enhanced the thermal
stability and hardness of the films as well.
Abstract: Poly vinyl acetate (PVA)-based titania (TiO2)–carbon
nanotube composite nanofibers (PVA-TCCNs) with various
PVA-to-solvent ratios and PVA-based TiO2 composite nanofibers
(PVA-TN) were synthesized using an electrospinning process,
followed by thermal treatment. The photocatalytic activities of these
nanofibers in the degradation of airborne monocyclic aromatics under
visible-light irradiation were examined. This study focuses on the
application of these photocatalysts to the degradation of the target
compounds at sub-part-per-million indoor air concentrations. The
characteristics of the photocatalysts were examined using scanning
electron microscopy, X-ray diffraction, ultraviolet-visible
spectroscopy, and Fourier-transform infrared spectroscopy. For all the
target compounds, the PVA-TCCNs showed photocatalytic
degradation efficiencies superior to those of the reference PVA-TN.
Specifically, the average photocatalytic degradation efficiencies for
benzene, toluene, ethyl benzene, and o-xylene (BTEX) obtained using
the PVA-TCCNs with a PVA-to-solvent ratio of 0.3 (PVA-TCCN-0.3)
were 11%, 59%, 89%, and 92%, respectively, whereas those observed
using PVA-TNs were 5%, 9%, 28%, and 32%, respectively.
PVA-TCCN-0.3 displayed the highest photocatalytic degradation
efficiency for BTEX, suggesting the presence of an optimal
PVA-to-solvent ratio for the synthesis of PVA-TCCNs. The average
photocatalytic efficiencies for BTEX decreased from 11% to 4%, 59%
to 18%, 89% to 37%, and 92% to 53%, respectively, when the flow
rate was increased from 1.0 to 4.0 L min1. In addition, the average
photocatalytic efficiencies for BTEX increased 11% to ~0%, 59% to
3%, 89% to 7%, and 92% to 13%, respectively, when the input
concentration increased from 0.1 to 1.0 ppm. The prepared
PVA-TCCNs were effective for the purification of airborne aromatics
at indoor concentration levels, particularly when the operating
conditions were optimized.
Abstract: Co metal supported on SiO2 and Al2O3 catalysts with
a metal loading varied from 30 of 70 wt.% were evaluated for
decomposition of methane to COx free hydrogen and carbon
nanomaterials. The catalytic runs were carried out from 550-800oC
under atmospheric pressure using fixed bed vertical flow reactor. The
fresh and spent catalysts were characterized by BET surface area
analyzer, XRD, SEM, TEM and TG analysis. The data showed that
50% Co/Al2O3 catalyst exhibited remarkable higher activity at 800oC
with respect to H2 production compared to rest of the catalysts.
However, the catalytic activity and durability was greatly declined at
higher temperature. The main reason for the catalytic inhibition of Co
containing SiO2 catalysts is the higher reduction temperature of
Co2SiO4. TEM images illustrate that the carbon materials with
various morphologies, carbon nanofibers (CNFs), helical-shaped
CNFs and branched CNFs depending on the catalyst composition and
reaction temperature were obtained.
Abstract: The rhizome of Java grass, Cyperus rotundus was
extracted different organic polar and non-polar solvents and
performed the in vitro antiviral and immunostimulant activities
against White Spot Syndrome Virus (WSSV) and Vibrio harveyi
respectively. Based on the initial screening the ethyl acetate extract of
C. rotundus was strong activities and further it was purified through
silica column chromatography and the fractions were screened again
for antiviral and immunostimulant activity. Among the different
fractions screened against the WSSV and V. harveyi, the fractions, FIII
to FV had strong activities. In order to study the in vivo influence
of C. rotundus, the fractions (F-III to FV) were pooled and delivered
to the F. indicus through artificial feed for 30 days. After the feeding
trail the experimental and control diet fed F. indicus were challenged
with virulent WSSV and studied the survival, molecular diagnosis,
biochemical, haematological, and immunological parameters.
Surprisingly, the pooled fractions (F-IV to FVI) incorporated diets
helped to significantly (P
Abstract: In order to detect and quantify the phenolic contents
of a wastewater with biosensors, two working electrodes based on
modified Poly(Pyrrole) films were fabricated. Enzyme horseradish
peroxidase was used as biomolecule of the prepared electrodes.
Various phenolics were tested at the biosensor. Phenol detection was
realized by electrochemical reduction of quinones produced by
enzymatic activity. Analytical parameters were calculated and the
results were compared with each other.
Abstract: Water contamination by toxic compound is one of the serious environmental problems today. These toxic compounds mostly originated from industrial effluents, agriculture, natural sources and human waste. These studies focus on modification of multiwalled carbon nanotube (MWCNTs) with nanoparticle of calixarene and explore the possibility of using this modification for the remediation of cadmium in water. The nanocomposites were prepared by dissolving calixarene in chloroform solution as solvent, followed by additional multiwalled carbon nanotube (MWCNTs) then sonication process for 3 hour and fabricated the nanocomposites on substrate by spin coating method. Finally, the nanocomposites were tested on cadmium ion (10 mg/ml). The morphology of nanocomposites was investigated by FESEM showing the formation of calixarene on the outer walls of carbon nanotube and cadmium ion also clearly seen from the micrograph. This formation was supported by using energy dispersive x-ray (EDX). The presence of cadmium ions in the films, leads to some changes in the surface potential and Fourier Transform Infrared spectroscopy (FTIR).The nanocomposites MWCNTs-calixarene have potential for development of sensor for pollutant monitoring and nanoelectronics devices applications.
Abstract: In Brazil, neonatal mortality rate is considered
incompatible with the country development conditions, and has been
a Public Health concern. Reduction in infant mortality rates has also
been part of the Millennium Development Goals, a commitment
made by countries, members of the Organization of United Nations
(OUN), including Brazil. Fetal mortality rate is considered a highly
sensitive indicator of health care quality. Suitable actions, such as
good quality and access to health services may contribute positively
towards reduction in these fetal and neonatal rates. With appropriate
antenatal follow-up and health care during gestation and delivery,
some death causes could be reduced or even prevented by means of
early diagnosis and intervention, as well as changes in risk factors
and interventions. Objectives: To study the quality of maternal and
infant health care based on fetal and neonatal mortality, as well as the
possible actions to prevent those deaths in Botucatu (Brazil).
Methods: Classification of prevention according to the International
Classification of Diseases and the modified Wigglesworth´s
classification. In order to evaluate adequacy, indicators of quality of
antenatal and delivery care were established by the authors. Results:
Considering fetal deaths, 56.7% of them occurred before delivery,
which reveals possible shortcomings in antenatal care, and 38.2% of
them were a result of intra- labor changes, which could be prevented
or reduced by adequate obstetric management. These findings were
different from those in the group of early neonatal deaths which were
also studied. Adequacy of health services showed that antenatal and
childbirth care was appropriate for 24% and 33.3% of pregnant
women, respectively, which corroborates the results of prevention.
These results revealed that shortcomings in obstetric and antenatal
care could be the causes of deaths in the study. Early and late
neonatal deaths have similar characteristics: 76% could be prevented
or reduced mainly by adequate newborn care (52.9%) and adequate
health care for gestational women (11.7%). When adequacy of care
was evaluated, childbirth and newborn care was adequate in 25.8%
and antenatal care was adequate in 16.1%. In conclusion, direct
relationship was found between adequacy and quality of care
rendered to pregnant women and newborns, and fetal and infant
mortality. Moreover, our findings highlight that deaths could be
prevented by an adequate obstetric and neonatal management.
Abstract: The contact resistance between source/drain electrodes
and semiconductor layer is an important parameter affecting electron
transporting performance in the thin film transistor (TFT). In this
work, we introduced a transparent and the solution prossable
single-walled carbon nanotube (SWCNT)/Al-doped ZnO nano particle
(AZO NP) bilayer electrodes showing low contact resistance with
indium-oxide (In2O3) sol gel thin film. By inserting low work function
AZO NPs into the interface between the SWCNTs and the In2O3 which
has a high energy barrier, we could obtain an electrical Ohmic contact
between them. Finally, with the SWCNT-AZO NP bilayer electrodes,
we successfully fabricated a TFT showing a field effect mobility of
5.38 cm2/V·s at 250°C.
Abstract: Adsorption of a boron nitride nanotube (BNNT) was
examined toward ethylacetylene (C4H6) molecule by using density
functional theory (DFT) calculations at the B3LYP/6-31G (d) level,
and it was found that the adsorption energy (Ead) of ethylacetylene
the pristine nanotubes is about -1.60kcal/mol. But when nanotube has
been doped with Si and Al atoms, the adsorption energy of
ethylacetylene molecule was increased. Calculation showed that
when the nanotube is doping by Al, the adsorption energy is about -
24.19kcal/mol and also the amount of HOMO/LUMO energy gap
(Eg) will reduce significantly. Boron nitride nanotube is a suitable
adsorbent for ethylacetylene and can be used in separation processes
ethylacetylene. It is seem that nanotube (BNNT) is a suitable
semiconductor after doping, and the doped BNNT in the presence of
ethylacetylene an electrical signal is generating directly and therefore
can potentially be used for ethylacetylene sensors.
Abstract: This paper investigates the viability of using carbon
fiber reinforced epoxy composites modified with carbon nanotubes to
strengthening reinforced concrete (RC) columns. Six RC columns
was designed and constructed according to ASCE standards. The
columns were wrapped using carbon fiber sheets impregnated with
either neat epoxy or CNTs modified epoxy. These columns were then
tested under concentric axial loading. Test results show that;
compared to the unwrapped specimens; wrapping concrete columns
with carbon fiber sheet embedded in CNTs modified epoxy resulted
in an increase in its axial load resistance, maximum displacement,
and toughness values by 24%, 109% and 232%, respectively. These
results reveal that adding CNTs into epoxy resin enhanced the
confinement effect, specifically, increased the axial load resistance,
maximum displacement, and toughness values by 11%, 6%, and
19%, respectively compared with columns strengthening with carbon
fiber sheet embedded in neat epoxy.
Abstract: Carbon nanotube is one of the most attractive materials
for the potential applications of nanotechnology due to its excellent
mechanical, thermal, electrical and optical properties. In this paper we
report a supercapacitor made of nickel foil electrodes, coated with
multiwall carbon nanotubes (MWCNTs) thin film using
electrophoretic deposition (EPD) method. Chemical vapor deposition
method was used for the growth of MWCNTs and ethanol was used as
a hydrocarbon source. High graphitic multiwall carbon nanotube was
found at 750oC analyzing by Raman spectroscopy. We observed the
electrochemical performance of supercapacitor by cyclic
voltammetry. The electrodes of supercapacitor fabricated from
MWCNTs exhibit considerably small equivalent series resistance
(ESR), and a high specific power density. Electrophoretic deposition
is an easy method in fabricating MWCNT electrodes for high
performance supercapacitor.
Abstract: In this study, epoxy composite specimens reinforced
with multi-walled carbon nanotube filler were fabricated using shear
mixer and ultra-sonication processor. The mechanical and thermal
properties of the fabricated specimens were measured and evaluated.
From the electron microscope images and the results from the
measurements of tensile strengths, the specimens having 0.6 wt%
nanotube content show better dispersion and higher strength than those
of the other specimens. The Young’s moduli of the specimens
increased as the contents of the nanotube filler in the matrix were
increased. The specimen having a 0.6 wt% nanotube filler content
showed higher thermal conductivity than that of the other specimens.
While, in the measurement of thermal expansion, specimens having
0.4 and 0.6 wt% filler contents showed a lower value of thermal
expansion than that of the other specimens. On the basis of the
measured and evaluated properties of the composites, we believe that
the simple and time-saving fabrication process used in this study was
sufficient to obtain improved properties of the specimens.
Abstract: The influence of three different types of halloysite
nanotubes (HNTs) with different dimensions, namely as camel lake
(CLA), Jarrahdale (JA) and Matauri Bay (MB), on their reinforcing
ability of ethylene propylene dine monomer (EPDM) were
investigated by varying the HNTs loading (from 0-15 phr).
Mechanical properties of the nanocomposites improved with addition
of all three HNTs, but CLA based nanocomposites exhibited a
significant enhancement compared to the other HNTs. For instance,
tensile properties of EPDM nanocomposites increased by 120%,
256% and 340% for MB, JA and CLA, respectively, with addition of
15 phr of HNTs. This could be due to the higher aspect ratio and
higher surface area of CLA compared to others. Scanning electron
microscopy (SEM) of nanocomposites at 15 phr of HNT loadings
showed low amounts of pulled-out nanotubes which confirmed the
presence of more embedded nanotubes inside the EPDM matrix, as
well as aggregates within the fracture surface of EPDM/HNT
nanocomposites