Abstract: Dynamics of laser radiation – metal target interaction
in water at 1064 nm by applying Mach-Zehnder interference
technique was studied. The mechanism of generating the well
developed regime of evaporation of a metal surface and a spherical
shock wave in water is proposed. Critical intensities of the NIR for
the well developed evaporation of silver and gold targets were
determined. Dynamics of shock waves was investigated for earlier
(dozens) and later (hundreds) nanoseconds of time. Transparent
expanding plasma-vapor-compressed water object was visualized and
measured. The thickness of compressed layer of water and pressures
behind the front of a shock wave for later time delays were obtained
from the optical treatment of interferograms.
Abstract: The steady mixed convection boundary layer flow from
a vertical cone in a porous medium filled with a nanofluid is
numerically investigated using different types of nanoparticles as Cu
(copper), Al2O3 (alumina) and TiO2 (titania). The boundary value
problem is solved by using the shooting technique by reducing it
into an ordinary differential equation. Results of interest for the local
Nusselt number with various values of the constant mixed convection
parameter and nanoparticle volume fraction parameter are evaluated.
It is found that dual solutions exist for a certain range of mixed
convection parameter.
Abstract: Noble metal participation in nanostructured
semiconductor catalysts has drawn much interest because of their
improved properties. Recently, it has been discussed by many
researchers that Ag participation in TiO2, CuO, ZnO semiconductors
showed improved photocatalytic and optical properties. In this
research, Ag/ZnO nanocomposite particles were prepared by
Ultrasonic Spray Pyrolysis(USP) Method. 0.1M silver and zinc
nitrate aqueous solutions were used as precursor solutions. The
Ag:Zn atomic ratio of the solution was selected 1:1. Experiments
were taken place under constant air flow of 400 mL/min at 800°C
furnace temperature. Particles were characterized by X-Ray
Diffraction (XRD), Scanning Electron Microscope (SEM) and
Energy Dispersive Spectroscopy (EDS). The crystallite sizes of Ag
and ZnO in composite particles are 24.6 nm, 19.7 nm respectively.
Although, spherical nanocomposite particles are in a range of 300-
800 nm, these particles are formed by the aggregation of primary
particles which are in a range of 20-60 nm.
Abstract: Buoyancy driven heat transfer of nanofluids in a
cylindrical enclosure used as a control unit in the subsea hydrocarbon
injection wells is investigated in this study. The governing equations
obtained with the Boussinesq approximation are solved using Comsol
Multiphysics finite element analysis and simulation software. The
base fluid is water and CuO is used as nanoparticles. Solution is
obtained for nanoparticle solid volume fraction of 8% and for
Rayleigh number in the range of 105-107. The results show that
nanoparticle usage in the cylindrical electronic control unit has a
significant effect on the flow and heat transfer.
Abstract: Thermoplastic starch, polylactic acid glycerol and
maleic anhydride (MA) were compounded with natural
montmorillonite (MMT) through a twin screw extruder to investigate
the effects of different loading of MMT on structure, thermal and
absorption behavior of the nanocomposites. X-ray diffraction analysis
(XRD) showed that sample with MMT loading 4phr exhibited
exfoliated structure while sample that contained MMT 8 phr
exhibited intercalated structure. FESEM images showed big lump
when MMT loading was at 8 phr. The thermal properties were
characterized by using differential scanning calorimeter (DSC). The
results showed that MMT increased melting temperature and
crystallization temperature of matrix but reduction in glass transition
temperature was observed Meanwhile the addition of MMT has
improved the water barrier property. The nanosize MMT particle is
also able to block a tortuous pathway for water to enter the starch
chain, thus reducing the water uptake and improved the physical
barrier of nanocomposite.
Abstract: Thermal conductivity is an important characteristic of
a nanofluid in laminar flow heat transfer. This paper presents an
improved model for the prediction of the effective thermal
conductivity of nanofluids based on dimensionless groups. The
model expresses the thermal conductivity of a nanofluid as a function
of the thermal conductivity of the solid and liquid, their volume
fractions and particle size. The proposed model includes a parameter
which accounts for the interfacial shell, brownian motion, and
aggregation of particle. The validation of the model is verified by
applying the results obtained by the experiments of Tio2-water and
Al2o3-water nanofluids.
Abstract: Nano-MgO was successfully deposited on titania using deposition-precipitation method. The catalyst produced was characterised using FTIR, XRD, BET and XRF and its activity was tested on the transesterification reaction of soybean oil to biodiesel. The catalyst activity improved when the reaction temperature was increasedfrom 150 and 225 OC. It was also observed that increasing the reaction time above 1h had no significant benefit on conversion. The stability fixed MgO on TiO2 was investigated using XRF and ICP-OES. It was observed that MgO loss during the reaction was between 0.5-2.3 percent and that there was no correlation between the reaction temperature and the MgO loss.
Abstract: A biosensor based on glucose oxidase (GOx) immobilized onto nanoparticles zirconium oxide with polyethylene nanocomposite for glucose monitoring has been designed. The CTAB/PEG/ZrO2/GOx nanocomposite was deposited onto screen printed carbon paste (SPCE) electrode via spin coating technique. The properties of CTAB/PEG/ZrO2/GOx were study using scanning electron microscopy (SEM). The SPE modified with the CTAB/PEG/ZrO2/GOx showed electrocatalytical response to the oxidation of glucose when ferrocene carboxaldehyde was used as an artificial redox mediator, which was studied by cyclic voltammetry (CV). Several parameters such as working potential, effect of pH and effect of ZrO2/PEG layers that governed the analytical performance of the biosensor, have been studied. The biosensor was applied to detect glucose with a linear range of 0.4 to 2.0 mmol L−1 with good repetability and reproducibility.
Abstract: The paper is concerned with the technological process of renovation of shafts used in industrial manufacturing for extruding of sheet material. In the classical renovation technologies, a chrome based coating is applied to the working surface of the shaft in galvanic baths. The process, however, is known to be exclusively harmful due to the waste cyanide products. In this work, we present an advanced nanotechnology based on nonelectric chemical laying of a nickel coating with included nanoparticles. The technology is environmentally harmless and the new coating features an increased hardness and wear resistance. Results from experimental tests of the nanostructured nickel coating are presented and discussed.
Abstract: A simple approach is demonstrated for growing large
scale, nearly vertically aligned ZnO nanowire arrays by thermal
oxidation method. To reveal effect of temperature on growth and
physical properties of the ZnO nanowires, gold coated zinc substrates
were annealed at 300 °C and 400 °C for 4 hours duration in air. Xray
diffraction patterns of annealed samples indicated a set of well
defined diffraction peaks, indexed to the wurtzite hexagonal phase of
ZnO. The scanning electron microscopy studies show formation of
ZnO nanowires having length of several microns and average of
diameter less than 500 nm. It is found that the areal density of wires
is relatively higher, when the annealing is carried out at higher
temperature i.e. at 400°C. From the field emission studies, the values
of the turn-on and threshold field, required to draw emission current
density of 10 μA/cm2 and 100 μA/cm2 are observed to be 1.2 V/μm
and 1.7 V/μm for the samples annealed at 300 °C and 2.9 V/μm and
3.7 V/μm for that annealed at 400 °C, respectively. The field
emission current stability, investigated over duration of more than 2
hours at the preset value of 1 μA, is found to be fairly good in both
cases. The simplicity of the synthesis route coupled with the
promising field emission properties offer unprecedented advantage
for the use of ZnO field emitters for high current density
applications.
Abstract: The value of emission factor was calculated in the
older type of Diesel engine operating on an engine testing bench and
then compared with the parameters monitored under similar
conditions when the EnviroxTM additive was applied. It has been
found out that the additive based on CeO2 nanoparticles reduces
emission of NOx. The dependencies of NOx emissions on reduced
torque, engine power and revolutions have been observed as well.
Abstract: novel and simple method is introduced for rapid and
highly efficient water treatment by reverse osmosis (RO) method using
multi-walled carbon nanotubes (MWCNTs) / polyacrylonitrile (PAN)
polymer as a flexible, highly efficient, reusable and semi-permeable
mixed matrix membrane (MMM). For this purpose, MWCNTs were
directly synthesized and on-line purified by chemical vapor deposition
(CVD) process, followed by directing the MWCNT bundles towards an
ultrasonic bath, in which PAN polymer was simultaneously suspended
inside a solid porous silica support in water at temperature to ~70 οC.
Fabrication process of MMM was finally completed by hot isostatic
pressing (HIP) process. In accordance with the analytical figures of
merit, the efficiency of fabricated MMM was ~97%. The rate of water
treatment process was also evaluated to 6.35 L min-1. The results reveal
that, the CNT-based MMM is suitable for rapid treatment of different
forms of industrial, sea, drinking and well water samples.
Abstract: This paper applies the homotopy analysis method method to a nonlinear differential-difference equation arising in nanotechnology. Continuum hypothesis on nanoscales is invalid, and a differential-difference model is considered as an alternative approach to describing discontinued problems. Comparison of the approximate solution with the exact one reveals that the method is very effective.
Abstract: Carriers scattering in the inversion channel of n-
MOSFET dominates the drain current. This paper presents an effective
electron mobility model for the pocket implanted nano scale
n-MOSFET. The model is developed by using two linear pocket
profiles at the source and drain edges. The channel is divided into
three regions at source, drain and central part of the channel region.
The total number of inversion layer charges is found for these three
regions by numerical integration from source to drain ends and the
number of depletion layer charges is found by using the effective
doping concentration including pocket doping effects. These two
charges are then used to find the effective normal electric field,
which is used to find the effective mobility model incorporating the
three scattering mechanisms, such as, Coulomb, phonon and surface
roughness scatterings as well as the ballistic phenomena for the
pocket implanted nano-scale n-MOSFET. The simulation results show
that the derived mobility model produces the same results as found
in the literatures.
Abstract: Chemical vapor deposition method was used to
produce carbon nanotubes on an iron based catalyst from acetylene.
Gas-phase samples collected from the different positions of the tubular reactor were analyzed by GC/MS. A variety of species ranging from hydrogen to naphthalene were observed and changes in their concentrations were plotted against the reactor position. Briefly benzene, toluene, styrene, indene and naphthalene were the main
higher molecular weight species and vinylacetylene and diacetylene were the important intermediates. Nanotube characterization was performed by scanning electron microscopy and transmission electron microscopy.
Abstract: Platinum oxide nanoparticles were prepared by a
simple hydrothermal route and chemical reduction using
carbohydrates (Fructose and sucrose) as the reducing and
stabilizing agents. The crystallite size of these nanoparticles was
evaluated from X-ray diffraction (XRD), atomic force microscopy
(AFM) and transmission electron microscopy (TEM) and was
found to be 10 nm as shown in figure 1, which is the
demonstration of EM bright field and transmission electron
microscopy. The effect of carbohydrates on the morphology of the
nanoparticles was studied using TEM (Figure 1). The
nanoparticles (100 μg/ml) were administered to the Pseudomonas
Stutzeri and Lactobacillus cultures and the incubation was done at
35 oC for 24 hours. The nanocomposites exhibited interesting
inhibitory as well as bactericidal activity against P. Stutzeri and
and Lactobacillus species. Incorporation of nanoparticles also
increased the thermal stability of the carbohydrates.
Abstract: (Bi0.5Na0.5)TiO3 doped with 8 mol % BaTiO3 powder
(BNT-BT0.08), prepared by sol-gel method was compacted and
sintered by Spark Plasma Sintering (SPS) process. The influence of
SPS temperature on the densification of BNT-BT0.08 ceramic was
investigated. Starting from sol-gel nanopowder of BNT-BT
containing 8 mol % BaTiO3 with an average particles size of about
30 nm, were obtained ceramics with density around 98 % of the
theoretical density value when the SPS temperature used was about
850 °C. The average grain size of the resulting ceramics was 80 nm.
The BNT-BT0.08 ceramic sample obtained by SPS method has shown
good electric properties at various frequencies.
Abstract: The use of Quantum dots is a promising emerging
Technology for implementing digital system at the nano level. It is
effecient for attractive features such as faster speed , smaller size and
low power consumption than transistor technology. In this paper,
various Combinational and sequential logical structures - HALF
ADDER, SR Latch and Flip-Flop, D Flip-Flop preceding NAND,
NOR, XOR,XNOR are discussed based on QCA design, with
comparatively less number of cells and area. By applying these
layouts, the hardware requirements for a QCA design can be reduced.
These structures are designed and simulated using QCA Designer
Tool. By taking full advantage of the unique features of this
technology, we are able to create complete circuits on a single layer
of QCA. Such Devices are expected to function with ultra low
power Consumption and very high speeds.
Abstract: A semi-analytic boundary discretization method, the Method of Auxiliary Sources (MAS) is used to analyze Optical Antennas consisting of metallic parts. In addition to standard dipoletype antennas, consisting of two pieces of metal, a new structure consisting of a single metal piece with a tiny groove in the center is analyzed. It is demonstrated that difficult numerical problems are caused because optical antennas exhibit strong material dispersion, loss, and plasmon-polariton effects that require a very accurate numerical simulation. This structure takes advantage of the Channel Plasmon-Polariton (CPP) effect and exhibits a strong enhancement of the electric field in the groove. Also primitive 3D antenna model with spherical nano particles is analyzed.
Abstract: Titanium dioxide coatings were deposited by utilizing
atmospheric plasma spraying (APS) system. The agglomerated nanopowder
and different spraying parameters were used to determine
their influences on the microstructure surface feature and photoabsorption
of the coatings. The microstructure of as-sprayed TiO2
coatings were characterized by scanning electron microscope (SEM).
Surface characteristics were investigated by Fourier Transform
Infrared (FT-IR). The photo absorption was determined by UV-VIS
spectrophotometer. It is found that the spray parameters have an
influence on the microstructure, surface feature and photo-absorption
of the TiO2 coatings.