Abstract: In this study, we report the synthesis and
characterization of nanohydroxyapatite (nHAp) in gelatin-starch
matrix via biomimetic method. Characterization of the samples was
performed using X-ray diffraction (XRD) and Fourier Transform
infrared spectroscopy (FT-IR). The Size and morphology of the
nHAp samples were determined using scanning and transmission
electron microscopy (SEM and TEM). The results reveal that the
shape and morphology of nHAp is influenced by presence of
biopolymers as template. Carbonyl and amino groups from gelatin
and hydroxyl from starch play crucial roles in HAp formation on the
surface of gelatin-starch.
Abstract: Work is focused to the study of unburned carbon in
ash from coal (and wastes) combustion in 8 combustion tests at 3
fluidised-bed power station, at co-combustion of coal and wastes
(also at fluidized bed) and at bench-scale unit simulating coal
combustion in small domestic furnaces. The attention is paid to
unburned carbon contents in bottom ashes and fly ashes at these 8
combustion tests and to morphology of unburned carbons. Specific
surface area of coals, unburned carbons and ashes and the relation of
specific surface area of unburned carbon and the content of volatile
combustibles in coal were studied as well.
Abstract: The peng-Robinson (PR), a cubic equation of state (EoS), is extended to polymers by using a single set of energy (A1, A2, A3) and co-volume (b) parameters per polymer fitted to experimental volume data. Excellent results for the volumetric behavior of the 11 polymer up to 2000 bar pressure are obtained. The EoS is applied to the correlation and prediction of Henry constants in polymer solutions comprising three polymer and many nonpolar and polar solvents, including supercritical gases. The correlation achieved with two adjustable parameter is satisfactory compared with the experimental data. As a result, the present work provides a simple and useful model for the prediction of Henry's constant for polymer containing systems including those containing polar, nonpolar and supercritical fluids.
Abstract: Hydrodesulfurization (HDS) of dibenzothiophene
(DBT) in a high pressure batch reactor was done at 320 °C on
CoMoS/Al2O3-B2O3 (4, 10, and 16 wt. % of Boria) using nhexadecane
as solvent, dimethyldisulfide (DMDS) in tetradecane as
sulfur agent, and stirring at 1000 rpm. The effects of boria were
investigated by using X-ray diffraction (XRD), Temperature
programmed desorption (TPD) of ammonia, and Brunauer-Emmet-
Teller (BET) experiments. The results showed that the catalyst
prepared with low boria content (4 wt. %) had HDS activity (in
pseudo first order kinetic constant basis) value ~1.45 times higher to
that of CoMoS/Al2O3 catalyst.
Abstract: A kinetic model for propane dehydrogenation in an
industrial moving bed reactor is developed based on the reported
reaction scheme. The kinetic parameters and activity constant are
fine tuned with several sets of balanced plant data. Plant data at
different operating conditions is applied to validate the model and
the results show a good agreement between the model
predictions and plant observations in terms of the amount of main
product, propylene produced. The simulation analysis of key
variables such as inlet temperature of each reactor (Tinrx) and
hydrogen to total hydrocarbon ratio (H2/THC) affecting process
performance is performed to identify the operating condition to
maximize the production of propylene. Within the range of operating
conditions applied in the present studies, the operating condition to
maximize the propylene production at the same weighted average
inlet temperature (WAIT) is ΔTinrx1= -2, ΔTinrx2= +1, ΔTinrx3= +1 ,
ΔTinrx4= +2 and ΔH2/THC= -0.02. Under this condition, the surplus
propylene produced is 7.07 tons/day as compared with base case.
Abstract: The present work presents the extraction of copper(II)
from sulphuric acid solutions with Sodium diethyldithiocarbamate
(SDDT), and six different organic diluents: Dichloromethane,
Chloroform, Carbon tetrachloride, Toluene, xylene and Cyclohexane,
were tested. The pair SDDT/Chloroform showed to be the most
selective in removing the copper cations, and hence was considered
throughout the experimental study.
The effects of operating parameters such as the initial concentration
of the extracting agent, the agitation time, the agitation speed and the
acid concentration were considered.
For an initial concentration of Cu (II) of 63 ppm in a 0.5 M sulphuric
acid solution, both with a mass of the extracting agent of 20 mg, an
extraction percentage of about 97.8 % and a distribution coefficient
of 44.42 were obtained, respectively, confirming the performance
of the SDDT-Chloroform pair.
Abstract: Calcium is very important for communication among
the neurons. It is vital in a number of cell processes such as secretion,
cell movement, cell differentiation. To reduce the system of reactiondiffusion
equations of [Ca2+] into a single equation, two theories
have been proposed one is excess buffer approximation (EBA) other
is rapid buffer approximation (RBA). The RBA is more realistic than
the EBA as it considers both the mobile and stationary endogenous
buffers. It is valid near the mouth of the channel. In this work we have
studied the effects of different types of buffers on calcium diffusion
under RBA. The novel thing studied is the effect of sodium ions on
calcium diffusion. The model has been made realistic by considering
factors such as variable [Ca2+], [Na+] sources, sodium-calcium
exchange protein(NCX), Sarcolemmal Calcium ATPase pump. The
proposed mathematical leads to a system of partial differential equations
which has been solved numerically to study the relationships
between different parameters such as buffer concentration, buffer
disassociation rate, calcium permeability. We have used Forward
Time Centred Space (FTCS) approach to solve the system of partial
differential equations.
Abstract: An innovative approach utilizing highly alkaline oil
shale waste ash and carbon dioxide gas (CO2), associated with power
production, as a resource for production of precipitated calcium
carbonate (PCC) is introduced in this paper. The specifics and
feasibility of the integrated ash valorization and CO2 sequestration
process by indirect aqueous carbonation of lime-consisting ash were
elaborated and the main parameters established. Detailed description
of the formed precipitates was included. Complimentary carbonation
experiments with commercial CaO fine powder were conducted for
comparative characterization of the final products obtained on the
basis of two different raw materials. Finally, the expected CO2
uptake was evaluated.
Abstract: In this study, the ability of Aspergillus niger and
Penicillium simplicissimum to extract heavy metals from a spent
refinery catalyst was investigated. For the first step, a spent
processing catalyst from one of the oil refineries in Iran was
physically and chemically characterized. Aspergillus niger and
Penicillium simplicissimum were used to mobilize Al/Co/Mo/Ni from
hazardous spent catalysts. The fungi were adapted to the mixture of
metals at 100-800 mg L-1 with increments in concentration of 100 mg
L-1. Bioleaching experiments were carried out in batch cultures. To
investigate the production of organic acids in sucrose medium,
analyses of the culture medium by HPLC were performed at specific
time intervals after inoculation. The results obtained from Inductive
coupled plasma-optical emission spectrometry (ICP-OES) showed
that after the one-step bioleaching process using Aspergillus niger,
maximum removal efficiencies of 27%, 66%, 62% and 38% were
achieved for Al, Co, Mo and Ni, respectively. However, the highest
removal efficiencies using Penicillium simplicissimum were of 32%,
67%, 65% and 38% for Al, Co, Mo and Ni, respectively
Abstract: The paper reports the preparation and photocatalytic
activity of ZnO/SnO2 and SnO2 nanoparticles. These nanoparticles
were synthesized by hydrothermal method. The products were
characterized by X-ray diffraction (XRD) and scanning electron
microscopy (SEM). Their grain sizes are about 50-100 nm. The
photocatalytic activities of these materials were investigated for
congo red removal from aqueous solution under UV light irradiation.
It was shown that the use of ZnO/SnO2 as photocatalyst have better
photocatalytic activity for degradation of congo red than SnO2 or
TiO2 (anatase, particle size: 30nm) alone.
Abstract: Polymeric microreactors have emerged as a new
generation of carriers that hold tremendous promise in the areas of
cancer therapy, controlled delivery of drugs, for removal of
pollutants etc. Present work reports a simple and convenient
methodology for synthesis of polystyrene and poly caprolactone
microreactors. An aqueous suspension of carboxylated (1μm)
polystyrene latex particles was mixed with toluene solution followed
by freezing with liquid nitrogen. Freezed particles were incubated at
-20°C and characterized for formation of voids on the surface of
polymer microspheres by Field Emission Scanning Electron
Microscope. The hollow particles were then overnight incubated at
40ºC with unfunctionalized quantum dots (QDs) in 5:1 ratio. QDs
Encapsulated polystyrene microcapsules were characterized by
fluorescence microscopy.
Likewise Poly ε-caprolactone microreactors were prepared by
micro-volcanic rupture of freeze dried microspheres synthesized
using emulsification of polymer with aqueous Poly vinyl alcohol and
freezed with liquid nitrogen. Microreactors were examined with Field
Emission Scanning Electron Microscope for size and morphology.
Current study is an attempt to create hollow polymer particles which
can be employed for microencapsulation of nanoparticles and drug
molecules.
Abstract: Tungsten trioxide has been prepared by using P-PTA
as a precursor on alumina substrates by spin coating method.
Palladium introduced on WO3 film via electrolysis deposition by
using palladium chloride as catalytic precursor. The catalytic
precursor was introduced on the series of films with different
morphologies. X-ray diffractometry (XRD), Scanning electron
microscopy (SEM) and XPS were applied to analyze structure and
morphology of the fabricated thin films. Then we measured variation
of samples- electrical conductivity of pure and Pd added films in air
and diluted hydrogen. Addition of Pd resulted in a remarkable
improvement of the hydrogen sensing properties of WO3 by detection
of Hydrogen below 1% at room temperature. Also variation of the
electrical conductivity in the presence of diluted hydrogen revealed
that response of samples depends rather strongly on the palladium
configuration on the surface.
Abstract: Polyurethane foam (PUF) were prepared by
reacting polyols synthesized from soy-oil into mixture of 2,4-
Toluene diisocyanate (TDI) with 4,4--Methylene Diamine
Isocyanate (MDI) with ratio of 70:30. The polyols obtained
via esterification reaction were categorize into different
temperature of reaction and by used of varied concentration
of phosphoric acid catalyst. The purpose of catalysts is to
shifting selectivity to a desired and value added of product.
The effect of stoichiometric balance (molar ratio of
epoxide/ethylene glycol) to the concentration of the catalyst
on the final properties was evaluated.
Abstract: Nanostructured Iron Oxide with different
morphologies of rod-like and granular have been suc-cessfully
prepared via a solid-state reaction in the presence of NaCl, NaBr, NaI
and NaN3, respectively. The added salts not only prevent a drastic
increase in the size of the products but also provide suitable
conditions for the oriented growth of primary nanoparticles. The
formation mechanisms of these materials by solid-state reaction at
ambient temperature are proposed. The photocatalytic experiments
for congo red (CR) have demonstrated that the mixture of α-Fe2O3
and Fe3O4 nanostructures were more efficient than α-Fe2O3
nanostructures.
Abstract: The morphological parameter of a thin film surface
can be characterized by power spectral density (PSD) functions
which provides a better description to the topography than the RMS
roughness and imparts several useful information of the surface
including fractal and superstructure contributions. Through the
present study Nanoparticle copper/carbon composite films were
prepared by co-deposition of RF-Sputtering and RF-PECVD method
from acetylene gas and copper target. Surface morphology of thin
films is characterized by using atomic force microscopy (AFM). The
Carbon content of our films was obtained by Rutherford Back
Scattering (RBS) and it varied from .4% to 78%. The power values of
power spectral density (PSD) for the AFM data were determined by
the fast Fourier transform (FFT) algorithms. We investigate the effect
of carbon on the roughness of thin films surface. Using such
information, roughness contributions of the surface have been
successfully extracted.