Abstract: Chitosan functionalized Fe3O4-Au core shell
nanoparticles have been prepared using a two-step wet chemical
approach using NaBH4 as reducing agent for formation of Au in
ethylene glycol. X-ray diffraction studies shows individual phases of
Fe3O4 and Au in the as prepared samples with crystallite size of 5.9
and 11.4 nm respectively. The functionalization of the core-shell
nanostructure with Chitosan has been confirmed using Fourier
transform infrared spectroscopy along with signatures of octahedral
and tetrahedral sites of Fe3O4 below 600cm-1. Mössbauer
spectroscopy shows decrease in particle-particle interaction in
presence of Au shell (72% sextet) than pure oleic coated Fe3O4
nanoparticles (88% sextet) at room temperature. At 80K, oleic acid
coated Fe3O4 shows only sextets whereas the Chitosan functionalized
Fe3O4 and Chitosan functionalized Fe3O4@Au core shell show
presence of 5 and 11% doublet, respectively.
Abstract: The changes of the optical and structural properties of
Bismuth-Boro-Tellurite glasses pre and post gamma irradiation were
studied. Six glass samples, with different composition [(TeO2)0.7
(B2O3)0.3]1-x (Bi2O3)x prepared by melt quenching method were
irradiated with 25kGy gamma radiation at room temperature. The
Fourier Transform Infrared Spectroscopy (FTIR) was used to explore
the structural bonding in the prepared glass samples due to exposure,
while UV-VIS Spectrophotometer was used to evaluate the changes
in the optical properties before and after irradiation. Gamma
irradiation causes profound changes in the peak intensity as shown by
FTIR spectra which is due to the breaking of the network bonding.
Before gamma irradiation, the optical band gap, Eg value decreased
from 2.44 eV to 2.15 eV with the addition of Bismuth content. The
value kept decreasing (from 2.18 eV to 2.00 eV) following exposure
to gamma radiation due to the increase of non-bridging oxygen
(NBO) and the increase of defect in the glass. In conclusion, the glass
with high content of Bi2O3 (0.30Bi) give smallest Eg and show less
changes in FTIR spectra after gamma irradiation which indicate that
this glass is more resistant to gamma radiation compared to other
glasses.
Abstract: Non contact evaluation of the thickness of paint
coatings can be attempted by different destructive and nondestructive
methods such as cross-section microscopy, gravimetric mass
measurement, magnetic gauges, Eddy current, ultrasound or
terahertz. Infrared thermography is a nondestructive and non-invasive
method that can be envisaged as a useful tool to measure the surface
thickness variations by analyzing the temperature response. In this
paper, the thermal quadrupole method for two layered samples heated
up with a pulsed excitation is firstly used. By analyzing the thermal
responses as a function of thermal properties and thicknesses of both
layers, optimal parameters for the excitation source can be identified.
Simulations show that a pulsed excitation with duration of ten
milliseconds allows obtaining a substrate-independent thermal
response. Based on this result, an experimental setup consisting of a
near-infrared laser diode and an Infrared camera was next used to
evaluate the variation of paint coating thickness between 60 μm and
130 μm on two samples. Results show that the parameters extracted
for thermal images are correlated with the estimated thicknesses by
the Eddy current methods. The laser pulsed thermography is thus an
interesting alternative nondestructive method that can be moreover
used for nonconductive substrates.
Abstract: Coal fly ash is formed as a solid waste product from
the combustion of coal in coal fired power stations. Huge amounts of
fly ash are produced globally every year and are predicted to
increase. Nowadays, less than half of the fly ash is used as a raw
material for cement manufacturing, construction and the rest of it is
disposed as a waste causing yet another environmental concern. For
this reason, the recycling of this kind of slurries into useful materials
is quite important in terms of economical and environmental aspects.
The purpose of this study is to evaluate the Orhaneli and
Tuncbilek coal fly ashes for utilization in some industrial
applications. Therefore the mineralogical and chemical compositions
of these fly ashes were analyzed by X-ray fluorescence spectroscopy,
ourier-transform infrared spectrometer, and X-ray diffraction. The
silicon (Si) and aluminum (Al) in the fly ashes were activated by
alkali fusion technique with sodium hydroxide. The obtained extracts
were analyzed for Si and Al content by inductively coupled plasma
optical emission spectrometry.
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: In this work, we report, a systematic study on the
structural and optical properties of Pr-doped ZnO nanostructures and
PVA:Zn98Pr2O polymer matrix nanocomposites free standing films.
These particles are synthesized through simple wet chemical route
and solution casting technique at room temperature, respectively.
Structural studies carried out by X-ray diffraction method confirm
that the prepared pure ZnO and Pr doped ZnO nanostructures are in
hexagonal wurtzite structure and the microstrain is increased upon
doping. TEM analysis reveals that the prepared materials are in sheet
like nature. Absorption spectra show free excitonic absorption band
at 370 nm and red shift for the Pr doped ZnO nanostructures. The
PVA:Zn98Pr2O composite film exhibits both free excitonic and PVA
absorption bands at 282 nm. Fourier transform infrared spectral
studies confirm the presence of A1 (TO) and E1 (TO) modes of Zn-O
bond vibration and the formation of polymer composite materials.
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: In rapid industrial development, the demand for
high-strength and lightweight materials have been increased. Thus,
various CFRP (Carbon Fiber Reinforced Plastics) with composite
materials are being used. The design variables of CFRP are its
lamination direction, order and thickness. Thus, the hardness and
strength of CFRP depends much on their design variables. In this
paper, the lamination direction of CFRP was used to produce a
symmetrical ply [0°/0°, -15°/+15°, -30°/+30°, -45°/+45°, -60°/+60°,
-75°/+75° and 90°/90°] and an asymmetrical ply [0°/15°, 0°/30°,
0°/45°, 0°/60° 0°/75° and 0°/90°]. The bending flexure stress of the
CFRP specimen was evaluated through a bending test. Its thermal
property was measured using an infrared camera. The symmetrical
specimen and the asymmetrical specimen were analyzed. The results
showed that the asymmetrical specimen increased the bending loads
according to the increase in the orientation angle; and from 0°, the
symmetrical specimen showed a tendency opposite the asymmetrical
tendency because the tensile force of fiber differs at the vertical
direction of its load. Also, the infrared camera showed that the thermal
property had a trend similar to that of the mechanical properties.
Abstract: Near-infrared spectroscopy (NIRS) has been widely
used as a non-invasive method to measure brain activity, but it is
corrupted by baseline drift noise. Here we present a method to measure
regional cerebral blood flow as a derivative of NIRS output. We
investigate whether, when listening to languages, blood flow can
reasonably localize and represent regional brain activity or not. The
prefrontal blood flow distribution pattern when advanced
second-language listeners listened to a second language (L2) was most
similar to that when listening to their first language (L1) among the
patterns of mean and standard deviation. In experiments with 25
healthy subjects, the maximum blood flow was localized to the left
BA46 of advanced listeners. The blood flow presented is robust to
baseline drift and stably localizes regional brain activity.
Abstract: The increasing demand of gallium, indium and
rare-earth elements for the production of electronics, e.g. solid
state-lighting, photovoltaics, integrated circuits, and liquid crystal
displays, will exceed the world-wide supply according to current
forecasts. Recycling systems to reclaim these materials are not yet in
place, which challenges the sustainability of these technologies. This
paper proposes a multispectral imaging system as a basis for a vision
based recognition system for valuable components of electronics
waste. Multispectral images intend to enhance the contrast of images
of printed circuit boards (single components, as well as labels) for
further analysis, such as optical character recognition and entire
printed circuit board recognition. The results show, that a higher
contrast is achieved in the near infrared compared to ultraviolett and
visible light.
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 this study, composites were fabricated from oil
palm empty fruit bunch fiber and poly(lactic) acid by extrusion
followed by injection moulding. Surface of the fiber was pre-treated
by ultrasound in an alkali medium and treatment efficiency was
investigated by scanning electron microscopy (SEM) analysis and
Fourier transforms infrared spectrometer (FTIR). Effect of fiber
treatment on composite was characterized by tensile strength (TS),
tensile modulus (TM) and impact strength (IS). Furthermore,
biostrong impact modifier was incorporated into the treated fiber
composite to improve its impact properties. Mechanical testing
showed an improvement of up to 23.5% and 33.6% respectively for
TS and TM of treated fiber composite above untreated fiber
composite. On the other hand incorporation of impact modifier led to
enhancement of about 20% above the initial IS of the treated fiber
composite.
Abstract: Near infrared (NIR) spectroscopy has always been of
great interest in the food and agriculture industries. The development
of prediction models has facilitated the estimation process in recent
years. In this study, 110 crude palm oil (CPO) samples were used to
build a free fatty acid (FFA) prediction model. 60% of the collected
data were used for training purposes and the remaining 40% used for
testing. The visible peaks on the NIR spectrum were at 1725 nm and
1760 nm, indicating the existence of the first overtone of C-H bands.
Principal component regression (PCR) was applied to the data in
order to build this mathematical prediction model. The optimal
number of principal components was 10. The results showed
R2=0.7147 for the training set and R2=0.6404 for the testing set.
Abstract: Many of the ever-growing elderly population require
exercise, such as running, for health management. One important
element of a runner’s training is the choice of shoes for exercise; shoes
are important because they provide the interface between the feet and
road. When we purchase shoes, we may instinctively choose a pair
after trying on many different pairs of shoes. Selecting the shoes
instinctively may work, but it does not guarantee a suitable fit for
running activities. Therefore, if we could select suitable shoes for each
runner from the viewpoint of brain activities, it would be helpful for
validating shoe selection. In this paper, we describe how brain
activities show different characteristics during particular task,
corresponding to different properties of shoes. Using five subjects, we
performed a verification experiment, applying weight, softness, and
flexibility as shoe properties. In order to affect the shoe property’s
differences to the brain, subjects run for 10 min. Before and after
running, subjects conducted a paced auditory serial addition task
(PASAT) as the particular task; and the subjects’ brain activities
during the PASAT are evaluated based on oxyhemoglobin and
deoxyhemoglobin relative concentration changes, measured by
near-infrared spectroscopy (NIRS). When the brain works actively,
oxihemoglobin and deoxyhemoglobin concentration drastically
changes; therefore, we calculate the maximum values of concentration
changes. In order to normalize relative concentration changes after
running, the maximum value are divided by before running maximum
value as evaluation parameters. The classification of the groups of
shoes is expressed on a self-organizing map (SOM). As a result,
deoxyhemoglobin can make clusters for two of the three types of
shoes.
Abstract: Nitrogen-doped graphene quantum dots (N-GQDs)
were fabricated by microwave-assisted hydrothermal technique. The
optical properties of the N-GQDs were studied. The luminescence of
the N-GQDs can be tuned by varying the excitation wavelength.
Furthermore, two-photon luminescence of the N-GQDs excited by
near-infrared laser can be obtained. It is shown that N-doping play a
key role on two-photon luminescence. The N-GQDs are expected to
find application in biological applications including bioimaging and
sensing.
Abstract: Food contamination occurs during post process
handling. This leads to spoilage and growth of pathogenic
microorganisms in the food, thereby reducing its shelf life or
spreading of food borne diseases. Several methods are tried and one
of which is use of antimicrobial packaging. Here, papain, a protease
enzyme, is covalently immobilized with the help of glutarldehyde on
polyurethane and used as a food wrap to protect food from microbial
contamination. Covalent immobilization of papain was achieved at a
pH of 7.4; temperature of 4°C; glutaraldehyde concentration of 0.5%;
incubation time of 24h; and 50mg of papain. The formation of -C=Nobserved
in the Fourier transform infrared spectrum confirmed the
immobilization of the enzyme on the polymer. Immobilized enzyme
retained higher activity than the native free enzyme. The modified
polyurethane showed better reduction of Staphylococcus aureus
biofilm than bare polymer film (eight folds reduction in live colonies,
two times reduction in protein and 6 times reduction in
carbohydrates). The efficacy of this was studied by wrapping it over
S. aureus contaminated cottage cheese (paneer) and cheese and
stored at a temperature of 4°C for 7days. The modified film reduced
the bacterial contamination by eight folds when compared to the bare
film. FTIR also indicated reduction in lipids, sugars and proteins in
the biofilm.
Abstract: Multispectral screening systems are becoming more
popular because of their very interesting properties and applications.
One of the most significant applications of multispectral screening
systems is prevention of terrorist attacks. There are many kinds of
threats and many methods of detection. Visual detection of objects
hidden under clothing of a person is one of the most challenging
problems of threats detection. There are various solutions of the
problem; however, the most effective utilize multispectral
surveillance imagers. The development of imaging devices and
exploration of new spectral bands is a chance to introduce new
equipment for assuring public safety. We investigate the possibility
of long lasting detection of potentially dangerous objects covered
with various types of clothing. In the article we present the results of
comparative studies of passive imaging in three spectrums – visible,
infrared and terahertz.
Abstract: The detection of environmental gases, 12CO2, 13CO2,
and CH4, using near-infrared semiconductor lasers with a short
laser path length is studied by means of wavelength-modulation
spectroscopy. The developed system is compact and has high
sensitivity enough to detect the absorption peaks of isotopic 13CO2
of a 3-% CO2 gas at 2 μm with a path length of 2.4 m, where
its peak size is two orders of magnitude smaller than that of the
ordinary 12CO2 peaks. In addition, the detection of 12CO2 peaks of
a 385-ppm (0.0385-%) CO2 gas in the air is made at 2 μm with a
path length of 1.4 m. Furthermore, in pursuing the detection of an
ancient environmental CH4 gas confined to a bubble in ice at the
polar regions, measurements of the absorption spectrum for a trace
gas of CH4 in a small area are attempted. For a 100-% CH4 gas
trapped in a ∼ 1 mm3 glass container, the absorption peaks of CH4
are obtained at 1.65 μm with a path length of 3 mm, and also the
gas pressure is extrapolated from the measured data.
Abstract: Novel bio-based polymer electrolyte was synthesized
with LiClO4 as the main source of charge carrier. Initially,
polyurethane-LiClO4 polymer electrolytes were synthesized via
prepolymerization method with different NCO/OH ratios and labelled
them as PU1, PU2, PU3 and PU4. Fourier transform infrared (FTIR)
analysis indicates the co-ordination between Li+ ion and polyurethane
in PU1. Differential scanning calorimetry (DSC) analysis indicates
PU1 has the highest glass transition temperature (Tg) corresponds to
the most abundant urethane group which is the hard segment in PU1.
Scanning electron microscopy (SEM) shows the good miscibility
between lithium salt and the polymer. The study found that PU1
possessed the greatest ionic conductivity and the lowest activation
energy, Ea. All the polyurethanes exhibited linear Arrhenius
variations indicating ion transport via simple lithium ion hopping in
polyurethane. This research proves the NCO content in polyurethane
plays an important role in affecting the ionic conductivity of this
polymer electrolyte.
Abstract: This article presents summary on preparation and
characterization of zinc, copper, cadmium and cobalt chromite
nanocrystals, embedded in an amorphous silica matrix. The
ZnCr2O4/SiO2, CuCr2O4/SiO2, CdCr2O4/SiO2 and CoCr2O4/SiO2
nanocomposites were prepared by a conventional sol-gel method
under acid catalysis. Final heat treatment of the samples was carried
out at temperatures in the range of 900−1200 ◦C to adjust the
phase composition and the crystallite size, respectively. The resulting
samples were characterized by Powder X-ray diffraction (PXRD),
High Resolution Transmission Electron Microscopy (HRTEM),
Raman/FTIR spectroscopy and magnetic measurements. Formation
of the spinel phase was confirmed in all samples. The average size of
the nanocrystals was determined from the PXRD data and by direct
particle size observation on HRTEM; both results were correlated.
The mean particle size (reviewed by HRTEM) was in the range from
∼4 to 46 nm. The results showed that the sol-gel method can be
effectively used for preparation of the spinel chromite nanoparticles
embedded in the silica matrix and the particle size is driven by the
type of the cation A2+ in the spinel structure and the temperature
of the final heat treatment. Magnetic properties of the nanocrystals
were found to be just moderately modified in comparison to the bulk
phases.