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 this paper, extract of papaya leaves are used as a
natural dye and combined by variations of solvent concentration
applied on DSSC (Dye-Sensitized Solar Cell). Indonesian geographic
located on the equator line occasions the magnitude of the potential
to develop organic solar cells made from extracts of chlorophyll as a
substitute for inorganic materials or synthetic dye on DSSC material.
Dye serves as absorbing photons which are then converted into
electrical energy. A conductive coated glass layer called TCO
(Transparent Conductive Oxide) is used as a substrate of electrode.
TiO2 nanoparticles as binding dye molecules, redox couple iodide/
tri-iodide as the electrolyte and carbon as the counter electrode in the
DSSC are used. TiO2 nanoparticles, organic dyes, electrolytes, and
counter electrode are arranged and combined with the layered
structure of the photo-catalyst absorption layer. Dye absorption
measurements using a spectrophotometer at 400-800 nm light
spectrum produces a total amount of chlorophyll 80.076 mg/l. The
test cell at 7 watt LED light with 5000 lux luminescence was
obtained Voc and Isc of 235.5 mV and 14 μA, respectively.
Abstract: Water spray cooling is a technique typically used in
heat treatment and other metallurgical processes where controlled
temperature regimes are required. Water spray cooling is used in
static (without movement) or dynamic (with movement of the steel
plate) regimes. The static regime is notable for the fixed position of
the hot steel plate and fixed spray nozzle. This regime is typical for
quenching systems focused on heat treatment of the steel plate. The
second application of spray cooling is the dynamic regime. The
dynamic regime is notable for its static section cooling system and
moving steel plate. This regime is used in rolling and finishing mills.
The fixed position of cooling sections with nozzles and the
movement of the steel plate produce nonhomogeneous water
distribution on the steel plate. The length of cooling sections and
placement of water nozzles in combination with the nonhomogeneity
of water distribution lead to discontinued or interrupted cooling
conditions. The impact of static and dynamic regimes on cooling
intensity and the heat transfer coefficient during the cooling process
of steel plates is an important issue.
Heat treatment of steel is accompanied by oxide scale growth. The
oxide scale layers can significantly modify the cooling properties and
intensity during the cooling. The combination of static and dynamic
(section) regimes with the variable thickness of the oxide scale layer
on the steel surface impact the final cooling intensity. The study of
the influence of the oxide scale layers with different cooling regimes
was carried out using experimental measurements and numerical
analysis. The experimental measurements compared both types of
cooling regimes and the cooling of scale-free surfaces and oxidized
surfaces. A numerical analysis was prepared to simulate the cooling
process with different conditions of the section and samples with
different oxide scale layers.
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 work was one of the tasks of the
Manufacturing2Client project, whose objective was to develop a
frontal deflector to be commercialized in the automotive industry,
using new project and manufacturing methods. In this task, in
particular, it was proposed to develop the ability to predict
computationally the aerodynamic influence of flow in vehicles, in an
effort to reduce fuel consumption in vehicles from class 3 to 8. With
this aim, two deflector models were developed and their aerodynamic
performance analyzed. The aerodynamic study was done using the
Computational Fluid Dynamics (CFD) software Ansys CFX and
allowed the calculation of the drag coefficient caused by the vehicle
motion for the different configurations considered. Moreover, the
reduction of diesel consumption and carbon dioxide (CO2) emissions
associated with the optimized deflector geometry could be assessed.
Abstract: Reburning is a useful technology in reducing nitric
oxide through injection of a secondary hydrocarbon fuel. In this paper,
an experimental study has been conducted to evaluate the effect of fuel
lean reburning on NOx/CO reduction in LNG flame. Experiments
were performed in flames stabilized by a co-flow swirl burner, which
was mounted at the bottom of the furnace. Tests were conducted using
LNG gas as the reburn fuel as well as the main fuel. The effects of
reburn fuel fraction and injection manner of the reburn fuel were
studied when the fuel lean reburning system was applied. The paper
reports data on flue gas emissions and temperature distribution in the
furnace for a wide range of experimental conditions. At steady state,
temperature distribution and emission formation in the furnace have
been measured and compared. This paper makes clear that in order to
decrease both NOx and CO concentrations in the exhaust when the
pulsated fuel lean reburning system was adapted, it is important that
the control of some factors such as frequency and duty ratio. Also it
shows the fuel lean reburning is also effective method to reduce NOx
as much as reburning.
Abstract: In this work, a polyaniline/Iron oxide (PANI/Fe2O3)
composite was chemically prepared by oxidative polymerization of
aniline in acid medium, in presence of ammonium persulphate as an
oxidant and amount of Fe2O3. The composite was characterized by a
scanning electron microscopy (SEM). The prepared composite has
been used as adsorbent to remove Tartrazine dye form aqueous
solutions.
The effects of initial dye concentration and temperature on the
adsorption capacity of PANI/Fe2O3 for Tartrazine dye have been
studied in this paper.
The Langmuir and Freundlich adsorption models have been used
for the mathematical description of adsorption equilibrium data. The
best fit is obtained using the Freundlich isotherm with an R2 value of
0.998. The change of Gibbs energy, enthalpy, and entropy of
adsorption has been also evaluated for the adsorption of Tartrazine
onto PANI/ Fe2O3. It has been proved according the results that the
adsorption process is endothermic in nature.
Abstract: This paper illustrates the effect of nano Magnesium
Hydroxide (MH) loading on the thermal properties of Low Density
Polyethylene (LDPE)/Poly (ethylene-co vinyl acetate) (EVA) nano
composite. Thermal studies were conducted, as it understanding is
vital for preliminary development of new polymeric systems.
Thermal analysis of nanocomposite was conducted using thermo
gravimetric analysis (TGA), and differential scanning calorimetry
(DSC). Major finding of TGA indicated two main stages of
degradation process found at (350 ± 25oC) and (480 ± 25oC)
respectively. Nano metal filler expressed better fire resistance as it
stand over high degree of temperature. Furthermore, DSC analysis
provided a stable glass temperature around 51 (±1oC) and captured
double melting point at 84 (±2oC) and 108 (±2oC). This binary
melting point reflects the modification of nano filler to the polymer
matrix forming melting crystals of folded and extended chain. The
percent crystallinity of the samples grew vividly with increasing filler
content. Overall, increasing the filler loading improved the
degradation temperature and weight loss evidently and a better
process and phase stability was captured in DSC.
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: Magnetic powder of Sr-ferrite was prepared by
conventional and sol-gel auto-combustion methods. In conventional
method, strontium carbonate and ferric oxide powders were mixed
together and then mixture was calcined. In sol-gel auto-combustion
method, a solution containing strontium nitrate, ferric nitrate and
citric acid was heated until the combustion took place automatically;
then, as-burnt powder was calcined. Thermal behavior, phase
identification, morphology and magnetic properties of powders
obtained by these two methods were compared by DTA, XRD, SEM
and VSM techniques. According to the results of DTA analysis,
formation temperature of Sr-ferrite obtained by conventional and solgel
auto-combustion methods were 1300°C and 1000°C, respectively.
XRD results confirmed the formation of pure Sr-ferrite at the
mentioned temperatures. Plate and hexagonal-shape particles of Srferrite
were observed using SEM. The Sr-ferrite powder obtained by
sol-gel auto-combustion method had saturation magnetization of
66.03 emu/g and coercivity of 5731 Oe in comparison with values of
58.20 emu/g and 4378 Oe obtained by conventional method.
Abstract: The main objective of the study is focused in
producing slag based geopolymer concrete obtained with the addition
of alkali activator. Test results indicated that the reaction of silicates
in slag is based on the reaction potential of sodium hydroxide and the
formation of alumino-silicates. The study also comprises on the
evaluation of the efficiency of polymer reaction in terms of the
strength gain properties for different geopolymer mixtures.
Geopolymer mixture proportions were designed for different binder
to total aggregate ratio (0.3 & 0.45) and fine to coarse aggregate ratio
(0.4 & 0.8). Geopolymer concrete specimens casted with normal
curing conditions reported a maximum 28 days compressive strength
of 54.75 MPa. The addition of glued steel fibres at 1.0% Vf in
geopolymer concrete showed reasonable improvements on the
compressive strength, split tensile strength and flexural properties of
different geopolymer mixtures. Further, comparative assessment was
made for different geopolymer mixtures and the reinforcing effects of
steel fibres were investigated in different concrete matrix.
Abstract: Preparation of nanoparticles of cerium oxide and
adsorption of bovine serum albumin on them were studied. Particle
size distribution and influence of pH on zeta potential of prepared
CeO2 were determined. Average size of prepared cerium oxide
nanoparticles was 9 nm. The simultaneous measurements of the
bovine serum albumin adsorption and zeta potential determination of
the (adsorption) suspensions were carried out. The adsorption
isotherms were found to be of typical Langmuir type; values of the
bovine serum albumin adsorption capacities were calculated.
Increasing of pH led to decrease of zeta potential and decrease of
adsorption capacity of cerium oxide nanoparticles. The maximum
adsorption capacity was found for strongly acid suspension (am =
118 mg/g). The samples of nanoceria with positive zeta potential
adsorbed more bovine serum albumin on the other hand, the samples
with negative zeta potential showed little or no protein adsorption.
Surface charge or better say zeta potential of CeO2 nanoparticles
plays the key role in adsorption of proteins on such type of materials.
Abstract: The current study explored the effect of economic
development, financial development and institutional quality on
environmental destruction in upper-middle income countries during
the time period of 1999-2011. The dependent variable is logarithm of
carbon dioxide emissions that can be considered as an index for
destruction or quality of the environment given to its effects on the
environment. Financial development and institutional development
variables as well as some control variables were considered. In order
to study cross-sectional correlation among the countries under study,
Pesaran and Friz test was used. Since the results of both tests show
cross-sectional correlation in the countries under study, seemingly
unrelated regression method was utilized for model estimation. The
results disclosed that Kuznets’ environmental curve hypothesis is
confirmed in upper-middle income countries and also, financial
development and institutional quality have a significant effect on
environmental quality. The results of this study can be considered by
policy makers in countries with different income groups to have
access to a growth accompanied by improved environmental quality.
Abstract: In the present study, we have synthesized Cr and Fe
doped zinc oxide (ZnO) nanostructures (Zn1-δCraFebO; where δ = a +
b = 20%, a = 5, 6, 8 & 10% and b = 15, 14, 12 & 10%) via sol-gel
method at different doping concentrations. The synthesized samples
were characterized for structural properties by X-ray diffractrometer
and field emission scanning electron microscope and the optical
properties were carried out through photoluminescence and UVvisible
spectroscopy. The particle size calculated through field
emission scanning electron microscope varies from 41 to 96 nm for
the samples synthesized at different doping concentrations. The
optical band gaps calculated through UV-visible spectroscopy are
found to be decreasing from 3.27 to 3.02 eV as the doping
concentration of Cr increases and Fe decreases.
Abstract: In the present work, hydrogen gas sensor of modest
sensitivity utilizing functionalized multiwalled carbon nanotubes
partially decorated with tin oxide nanoparticles (F-MWCNTs/SnO2)
has been fabricated. This sensing material was characterized by
scanning electron microscopy (SEM). In addition, a remarkable
finding was that the F-MWCNTs/SnO2 sensor shows good sensitivity
as compared to F-MWCNTs for low concentration (0.05-1% by
volume) of H2 gas. The fabricated sensors show complete resistance
recovery and good repeatability when exposed to H2 gas at the room
temperature conditions.
Abstract: Due to reduced stiffness, research on second
generation titanium alloys for implant applications, like the
metastable β-titanium alloy Ti-15Mo, become more and more
important in the recent years. The machinability of these alloys is
generally poor leading to problems during implant production and
comparably large production costs. Therefore, in the present study,
Ti-15Mo was alloyed with 0.8 wt.-% of the rare earth metals
lanthanum (Ti-15Mo+0.8La) and neodymium (Ti-15Mo+0.8Nd) to
improve its machinability. Their microstructure consisted of a
titanium matrix and micrometer-size particles of the rare earth metals
and two of their oxides. The particles stabilized the microstructure as
grain growth was minimized. As especially the ductility might be
affected by the precipitates, the behavior of Ti-15Mo+0.8La and Ti-
15Mo+0.8Nd was investigated during static and dynamic
deformation at elevated temperature to develop a processing route.
The resulting mechanical properties (static strength and ductility)
were similar in all investigated alloys.
Abstract: The aim of the present study is to investigate the
potential use of the selected seed oils. The oil was extracted using
Soxhlet apparatus and the physicochemical characteristics of the oil
determined using standard methods. The following results were
obtained for the physicochemical parameters analysed: for Egusi seed
oil, Oil yield 53.20%, Saponification value 178.03±1.25 mgKOH/g,
Iodine value 49.10±0.32 g I2/100g, Acid value 4.30±0.86 mgKOH/g,
and Peroxide value 5.80±0.27 meq/kg were obtained. For Pawpaw
seed oil, Oil yield 40.10%, Saponification value 24.13±3.93
mgKOH/g, Iodine value 24.87±0.19 g I2/100g, Acid value 9.46±0.40
mgKOH/g, and Peroxide value 3.12±1.22 meq/kg were obtained. For
Sweet orange seed oil, Oil yield 43.10%, Saponification value
106.30±2.37 mgKOH/g, Iodine value 37.08±0.04 g I2/100g, Acid
value 7.59±0.77 mgKOH/g, and Peroxide value 2.21±0.46 meq/kg
were obtained. From the obtained values of the determined
parameters, the oils can be extracted from the three selected seeds in
commercial quantities and that the egusi and sweet orange seed oils
may be utilized in the industrial soap production.
Abstract: Pomegranate (Punica granatum L.) is an ancient fruit of great medical interest and rich source of antioxidants. Pesticides as dimethoate play a crucial role in the occurrence many diseases in plants, animal and human. Therefore the ability of Pomegranate (Punica granatum L.) to alleviate hepatotoxicity induced by organophosphate pesticide dimethoate was investigated. Albino male rats were divided randomly into 4 groups and kept at 7 animals per group in an environmentally controlled condition for 6 weeks. The first group was served as a control group (basal diet), the second group fed on basal diet supplemented with 5% freeze dried pomegranate seeds, the third group fed on 20 ppm dimethoate contaminated diet and the last group fed on dimethoate contaminated diet supplemented with 5% freeze dried pomegranate seeds. The results revealed that administration of dimethoate caused high significant increased in liver functions: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activities as well as lipid peroxide (malonaldhyde, MDA); on the other hand high significant decreased on glutathione (GSH), glutathione peroxidase (GPx), albumin and total protein were observed. However addition of 5% freeze dried pomegranate seeds significantly improved all previously mentioned parameters. These results indicate the dimethoate induced hepatotoxicity and highlight the protective effect of pomegranate seeds as a potential protective agent against dimethoate induced hepatotoxicity. This may be attributed to the powerful antioxidants (polyphenols, total phenols, and total flavonoids) which present in high levels in pomegranate as well as improving the immunity by activation of antioxidant enzymes GSH and GPx.
Abstract: This work presents the modelling and simulation of
saponification of ethyl acetate in the presence of sodium hydroxide in
a plug flow reactor using Aspen Plus simulation software. Plug flow
reactors are widely used in the industry due to the non-mixing
property. The use of plug flow reactors becomes significant when
there is a need for continuous large scale reaction or fast reaction.
Plug flow reactors have a high volumetric unit conversion as the
occurrence for side reactions is minimum. In this research Aspen Plus
V8.0 has been successfully used to simulate the plug flow reactor. In
order to simulate the process as accurately as possible HYSYS Peng-
Robinson EOS package was used as the property method. The results
obtained from the simulation were verified by the experiment carried
out in the EDIBON plug flow reactor module. The correlation
coefficient (r2) was 0.98 and it proved that simulation results
satisfactorily fit for the experimental model. The developed model
can be used as a guide for understanding the reaction kinetics of a
plug flow reactor.
Abstract: The use of biodiesel in conventional diesel engines results in substantial reduction of unburned hydrocarbon, carbon monoxide and particulate matters. The performance, emission and combustion characteristics of a single cylinder four stroke variable compression ratio engine when fueled with Karanja (Pongamia) methyl ester and its 10-50 % blends with diesel (on a volume basis) are investigated and compared with standard diesel. The suitability of karanja methyl ester as a biofuel has been established in this study. The useful brake power obtained is similar to diesel fuel for all loads. Experiment has been conducted at a fixed engine speed of 1500 rpm, variable load and at compression ratios of 17.5:1 and 18.5:1. The impact of compression ratio on fuel consumption, combustion pressures and exhaust gas emissions has been investigated and presented. Optimum compression ratio which gives best performance has been identified. The results indicate longer ignition delay, maximum rate of pressure rise, lower heat release rate and higher mass fraction burnt at higher compression ratio for pongamia oil methyl ester when compared to that of diesel. The brake thermal efficiency for pongamia oil methyl ester blends and diesel has been calculated and the blend B20 is found to give maximum thermal efficiency. The blends when used as fuel results in reduction of carbon monoxide, hydrocarbon and increase in nitrogen oxides emissions. PME as an oxygenated fuel generated more complete combustion, which means increased torque and power. This is also supported with higher thermal efficiencies of the PME blends. NOx is slightly increased due to the higher combustion temperature and the presence of fuel oxygen with the blend at full load. PME as a new Biodiesel and its blends can be used in diesel engines without any engine modification.