Abstract: A nanocrystalline thin film of ZnSe was successfully
electrodeposited on copper substrate using a non-aqueous solution
and subsequently annealed in air at 400°C. XRD analysis indicates
the polycrystalline deposit of (111) plane in both the cases. The
sharpness of the peak increases due to annealing of the film and
average grain size increases to 20 nm to 27nm. SEM photograph
indicate that grains are uniform and densely distributed over the
surface. Annealing increases the average grain size by 20%. The EDS
spectroscopy shows the ratio of Zn & Se is 1.1 in case of annealed
film. AFM analysis indicates the average roughness of the film
reduces from 181nm to 165nm due to annealing of the film. The
bandgap also decreases from 2.71eV to 2.62eV.
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: Newly synthesized Polypropylene-g-Polyethylene
glycol polymer was first time used for a compartment-less enzymatic
fuel cell. Working electrodes based on Polypropylene-g-Polyethylene
glycol were operated as unmediated and mediated system (with
ferrocene and gold/cobalt oxide nanoparticles). Glucose oxidase and
bilirubin oxidase was selected as anodic and cathodic enzyme,
respectively. Glucose was used as fuel in a single-compartment and
membrane-less cell. Maximum power density was obtained as 0.65
nW cm-2, 65 nW cm-2 and 23500 nW cm-2 from the unmediated,
ferrocene and gold/cobalt oxide modified polymeric film,
respectively. Power density was calculated to be ~16000 nW cm-2 for
undiluted wastewater sample with gold/cobalt oxide nanoparticles
including system.
Abstract: In this study, we have focused our attention on
combining of molecular imprinting into nanofilms and QCM
nanosensor approaches and producing QCM nanosensor for anti-
CCP, chosen as model protein, using anti-CCP imprinted nanofilms.
The nonimprinted nanosensor was also prepared to evaluate the
selectivity of the imprinted nanosensor. Anti-CCP imprinted QCM
nanosensor was tested for real time detection of anti-CCP from
aqueous solution. The kinetic and affinity studies were determined by
using anti-CCP solutions with different concentrations. The
responses related with mass shifts (%m) and frequency shifts (%f)
were used to evaluate adsorption properties. To show the selectivity
of the anti-CCP imprinted QCM nanosensor, competitive adsorption
of anti-CCP and IgM was investigated. The results indicate that anti-
CCP imprinted QCM nanosensor has higher adsorption capabilities
for anti-CCP than for IgM, due to selective cavities in the polymer
structure.
Abstract: Thin ZnO films are deposited on glass substrates via
sol–gel method and dip-coating. The films are prepared from zinc
acetate dehydrate as a starting reagent. After that the as-prepared
ZnO sol is aged for different periods (0, 1, 3, 5, 10, 15 and 30 days).
Nanocrystalline thin films are deposited from various sols. The
effect ZnO sols aging time on the structural and photocatalytic
properties of the films is studied. The films surface is studied by
Scanning Electron Microscopy. The effect of the aging time of the
starting solution is studied in the photocatalytic degradation of
Reactive Black 5 (RB5) by UV-vis spectroscopy. The experiments
are conducted upon UV-light illumination and in complete darkness.
The variation of the absorption spectra shows the degradation of RB5
dissolved in water, as a result of the reaction, occurring on the surface
of the films and promoted by UV irradiation. The initial
concentrations of dye (5, 10 and 20 ppm) and the effect of the aging
time are varied during the experiments. The results show, that the
increasing aging time of starting solution with respect to ZnO
generally promotes photocatalytic activity. The thin films obtained
from ZnO sol, which is aged 30 days have best photocatalytic
degradation of the dye (97,22%) in comparison with the freshly
prepared ones (65,92%). The samples and photocatalytic
experimental results are reproducible. Nevertheless, all films exhibit
a substantial activity in both UV light and darkness, which is
promising for the development of new ZnO photocatalysts by sol-gel
method.
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: A new method for determining the distribution of
birefringence and linear dichroism in optical polymer materials is
presented. The method is based on the use of polarizationholographic
diffraction grating that forms an orthogonal circular basis
in the process of diffraction of probing laser beam on the grating. The
intensities ratio of the orders of diffraction on this grating enables the
value of birefringence and linear dichroism in the sample to be
determined. The distribution of birefringence in the sample is
determined by scanning with a circularly polarized beam with a
wavelength far from the absorption band of the material. If the
scanning is carried out by probing beam with the wavelength near to
a maximum of the absorption band of the chromophore then the
distribution of linear dichroism can be determined. An appropriate
theoretical model of this method is presented. A laboratory setup was
created for the proposed method. An optical scheme of the laboratory
setup is presented. The results of measurement in polymer films with
two-dimensional gradient distribution of birefringence and linear
dichroism are discussed.
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: The effect of the inclusion of thyme and rosemary
essential oils into chitosan films, as well as the microbiological and
physical properties when storing chitosan film with and without the
mentioned inclusion was studied. The film forming solution was
prepared by dissolving chitosan (2%, w/v), polysorbate 80 (4% w/w
CH) and glycerol (16% w/w CH) in aqueous lactic acid solutions
(control). The thyme (TEO) and rosemary (REO) essential oils (EOs)
were included 1:1 w/w (EOs:CH) on their combination 50/50
(TEO:REO). The films were stored at temperatures of 5, 20, 33°C
and a relative humidity of 75% during four weeks. The films with
essential oil inclusion did not show an antimicrobial activity against
strains. This behavior could be explained because the chitosan only
inhibits the growth of microorganisms in direct contact with the
active sites. However, the inhibition capacity of TEO was higher than
the REO and a synergic effect between TEO:REO was found for S.
enteritidis strains in the chitosan solution.
Some physical properties were modified by the inclusion of
essential oils. The addition of essential oils does not affect the
mechanical properties (tensile strength, elongation at break, puncture
deformation), the water solubility, the swelling index nor the DSC
behavior. However, the essential oil inclusion can significantly
decrease the thickness, the moisture content, and the L* value of
films whereas the b* value increased due to molecular interactions
between the polymeric matrix, the loosing of the structure, and the
chemical modifications. On the other hand, the temperature and time
of storage changed some physical properties on the chitosan films.
This could have occurred because of chemical changes, such as
swelling in the presence of high humidity air and the reacetylation of
amino groups. In the majority of cases, properties such as moisture
content, tensile strength, elongation at break, puncture deformation,
a*, b*, chrome, 7E increased whereas water resistance, swelling
index, L*, and hue angle decreased.
Abstract: A Silver (Ag) thin film is introduced as a template and
doping source for vertically aligned p–type ZnO nanorods. ZnO
nanorods were grown using an ammonium hydroxide based
hydrothermal process. During the hydrothermal process, the Ag thin
film was dissolved to generate Ag ions in the solution. The Ag ions can
contribute to doping in the wurzite structure of ZnO and the (111)
grain of Ag thin film can be the epitaxial temporal template for the
(0001) plane of ZnO. Hence, Ag–doped p–type ZnO nanorods were
successfully grown on the substrate, which can be an electrode or
semiconductor for the device application. To demonstrate the
potentials of this idea, p–n diode was fabricated and its electrical
characteristics were demonstrated.
Abstract: In view of a possible application in optical data
storage devices, diffraction grating efficiency of an organic dye, Acid
Fuchsin doped in PMMA matrix was studied under excitation with
CW diode pumped Nd: YAG laser at 532 nm. The open aperture Zscan
of dye doped polymer displayed saturable absorption and the
closed aperture Z-scan of the samples exhibited negative
nonlinearity. The diffraction efficiency of the grating is the ratio of
the intensity of the first order diffracted power to the incident read
beam power. The dye doped polymer films were found to be good
media for recording. It is observed that the formation of gratings
strongly depend on the concentration of dye in the polymer film, the
intensity ratios of the writing beams and the angle between the
writing beams. It has been found that efficient writing can be made at
an angle of 20o and when the intensity ratio of the writing beams is
unity.
Abstract: Replacement of plastics used in the food industry
seems to be a serious issue to overcome mainly the environmental
problems in recent years. This study investigates the hydrophilicity
and permeability properties of starch biopolymer which ethylene
vinyl alcohol (EVOH) (0-10%) and nanocrystalline cellulose (NCC)
(1-15%) were used to enhance its properties. Starch -EVOH
nanocomposites were prepared by casting method in different
formulations. NCC production by acid hydrolysis was confirmed by
scanning electron microscopy. Solubility, water vapor permeability,
water vapor transmission rate and moisture absorbance were
measured on each of the nanocomposites. The results were analyzed
by SAS software. The lowest moisture absorbance was measured in
pure starch nanocomposite containing 8% NCC. The lowest
permeability to water vapor belongs to starch nanocomposite
containing 8% NCC and the sample containing 7.8% EVOH and 13%
NCC. Also the lowest solubility was observed in the composite
contains the highest amount of EVOH. Applied Process resulted in
production of bio films which have good resistance to water vapor
permeability and solubility in water. The use of NCC and EVOH
leads to reduced moisture absorbance property of the biofilms.
Abstract: TiO2 thin films have been prepared by the sol-gel dipcoating
technique in order to elaborate antireflective thin films for
monocrystalline silicon (mono-Si). The titanium isopropoxyde was
chosen as a precursor with hydrochloric acid as a catalyser for
preparing a stable solution. The optical properties have been tailored
with varying the solution concentration, the withdrawn speed, and the
heat-treatment. We showed that using a TiO2 single layer with 64.5
nm in thickness, heat-treated at 450°C or 300°C reduces the mono-Si
reflection at a level lower than 3% over the broadband spectral
domains [669-834] nm and [786-1006] nm respectively. Those latter
performances are similar to the ones obtained with double layers of
low and high refractive index glasses respectively.
Abstract: This study investigates how AlGaAs/GaAs thin film
solar cells perform under varying global solar spectrum due to the
changes of environmental parameters such as the air mass and the
atmospheric turbidity. The solar irradiance striking the solar cell is
simulated using the spectral irradiance model SMARTS2 (Simple
Model of the Atmospheric Radiative Transfer of Sunshine) for clear
skies on the site of Setif (Algeria). The results show a reduction in the
short circuit current due to increasing atmospheric turbidity, it is
63.09% under global radiation. However increasing air mass leads to
a reduction in the short circuit current of 81.73%. The efficiency
decreases with increasing atmospheric turbidity and air mass.
Abstract: To develop AZ91D magnesium alloys with improved
properties, we have applied TiN and VN/TiN multilayer coatings
using DC magnetron sputter technique. Coating structure, surface
morphology, chemical bonding and corrosion resistance of coatings
were analyzed by x-ray diffraction (XRD), scanning electron
microscope (SEM), x-ray photoelectron spectroscopy (XPS), and
tafel extrapolation method, respectively. XPS analysis reveal that VN
overlayer reacts with oxygen at the VN/TiN interface and forms more
stable TiN layer. Morphological investigations and the corrosion
results show that VN/TiN multilayer thin film coatings are quite
effective to optimize the corrosion resistance of Mg alloys.
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: The present study was conducted to evaluate the
potential applicability of biological trickling filter system for the
treatment of simulated textile wastewater containing reactive azo
dyes with bacterial consortium under non-sterile conditions. The
percentage decolorization for the treatment of wastewater containing
structurally different dyes was found to be higher than 95% in all
trials. The stable bacterial count of the biofilm on stone media of the
trickling filter during the treatment confirmed the presence,
proliferation, dominance and involvement of the added microbial
consortium in the treatment of textile wastewater. Results of
physicochemical parameters revealed the reduction in chemical
oxygen demand (58.5-75.1%), sulphates (18.9-36.5%), and
phosphates (63.6-73.0%). UV-Visible and FTIR spectroscopy
confirmed decolorization of dye containing wastewater was ultimate
consequence of biodegradation. Toxicological studies revealed the
nontoxic nature of degradative metabolites.
Abstract: Vacuum insulation panel (VIP) is a promising thermal
insulator for buildings, refrigerator, LNG carrier and so on. In general,
it has the thermal conductivity of 2~4 mW/m·K. However, this thermal
conductivity is that measured at the center of VIP. The total effective
thermal conductivity of VIP is larger than this value due to the edge
conduction through the envelope. In this paper, the edge conduction of
VIP is examined theoretically, numerically and experimentally. To
confirm the existence of the edge conduction, numerical analysis is
performed for simple two-dimensional VIP model and a theoretical
model is proposed to calculate the edge conductivity. Also, the edge
conductivity is measured using the vacuum guarded hot plate and the
experiment is validated against numerical analysis. The results show
that the edge conductivity is dependent on the width of panel and
thickness of Al-foil. To reduce the edge conduction, it is recommended
that the VIP should be made as big as possible or made of thin Al film
envelope.
Abstract: Yttrium oxide (Y2O3) films have been successfully
deposited with yttrium-ethylenediamine tetraacetic acid (EDTA·Y·H)
complexes prepared by various milling techniques. The effects of the
properties of the EDTA·Y·H complex on the properties of the
deposited Y2O3 films have been analyzed. Seven different types of the
raw EDTA·Y·H complexes were prepared by various commercial
milling techniques such as ball milling, hammer milling, commercial
milling, and mortar milling. The milled EDTA·Y·H complexes
exhibited various particle sizes and distributions, depending on the
milling method. Furthermore, we analyzed the crystal structure,
morphology and elemental distribution profile of the metal oxide films
deposited on stainless steel substrate with the milled EDTA·Y·H
complexes. Depending on the milling technique, the flow properties of
the raw powders differed. The X-ray diffraction pattern of all the
samples revealed the formation of Y2O3 crystalline phase, irrespective
of the milling technique. Of all the different milling techniques, the
hammer milling technique is considered suitable for fabricating dense
Y2O3 films.
Abstract: The hydrogenated amorphous carbon films (α-C:H)
were deposited on p-type Si (100) substrates at different thicknesses by
radio frequency plasma enhanced chemical vapor deposition
technique (rf-PECVD). Raman spectra display asymmetric
diamond-like carbon (DLC) peaks, representative of the α-C:H films.
The decrease of intensity ID/IG ratios revealed the sp3 content arise at
different thicknesses of the α-C:H films. In terms of mechanical
properties, the high hardness and elastic modulus values showed the
elastic and plastic deformation behaviors related to sp3 content in
amorphous carbon films. Electrochemical properties showed that the
α-C:H films exhibited excellent corrosion resistance in air-saturated
3.5 wt.% NaCl solution for pH 2 at room temperature. Thickness
increasing affected the small sp2 clusters in matrix, restricting the
velocity transfer and exchange of electrons. The deposited α-C:H films
exhibited excellent mechanical properties and corrosion resistance.