Abstract: An optical chemical sensing film based on
immobilizing of 1,1′- diethyl 2,2′-cyanine (pseudocyanine iodide) in
nafion film was developed for the determination of Fe(III). The
sensing film was homogeneous, transparent, and mechanically stable.
Decrease of the absorbance measured at 518 nm was observed when
the sensing film was immersed in a solution of Fe(III). The optimum
response of the sensing film to Fe(III) was obtained in a solution with
pH 4.0. Linear calibration curve over an Fe(III) concentration range
of 1-30 ppm with a limit of detection of 0.71 ppm was obtained.
Cd(II) is the major interference. The sensing film exhibited good
stability for 2 months and high reproducibility. The proposed method
was applied for the determination of Fe(III) in water samples with
satisfactory results.
Abstract: This study was conducted to evaluate the anti-diabetic
properties of ethanolic extract of two plants commonly used in folk
medicine, Mormodica charantia (bitter melon) and Trigonella
foenum-graecum (fenugreek). The study was performed on STZinduced
diabetic rats (DM type-I). Plant extracts of these two plants
were given to STZ diabetic rats at the concentration of 500 mg/kg
body weight ,50 mg/kg body weight respectively. Cidophage®
(metformin HCl) were administered to another group to support the
results at a dose of 500 mg/kg body weight, the ethanolic extracts and
Cidophage administered orally once a day for four weeks using a
stomach tube and; serum samples were obtained for biochemical
analysis. The extracts caused significant decreases in glucose levels
compared with diabetic control rats. Insulin secretions were increased
after 4 weeks of treatment with Cidophage® compared with the
control non-diabetic rats. Levels of AST and ALT liver enzymes were
normalized by all treatments. Decreases in liver cholesterol,
triglycerides, and LDL in diabetic rats were observed with all
treatments. HDL levels were increased by the treatments in the
following order: bitter melon, Cidophage®, and fenugreek. Creatinine
levels were reduced by all treatments. Serum nitric oxide and
malonaldehyde levels were reduced by all extracts. GSH levels were
increased by all extracts. Extravasation as measured by the Evans
Blue test increased significantly in STZ-induced diabetic animals.
This effect was reversed by ethanolic extracts of bitter melon or
fenugreek.
Abstract: Papaya and banana bars were developed incorporating
inulin (IN) and fructooligosaccharides (FOS) (Liquid and Powder
form) in various proportions. The control bars were standardized
using 70% fruit pulp, 30% sugar, 0.3% citric acid while the treated
bars were standardized with 70% fruit pulp, 15% sugar, 15% of IN
and FOS and 0.3% citric acid. Among the various proportions tested,
papaya bars with 90% FOS (Powder) + 10% IN and banana bars with
90% FOS (liquid) + 10% IN were sensorially best accepted. The
study revealed that addition of IN and FOS improved the sensory
scores. The Physico-chemical and proximatecomposition analysis
revealed slight changes in brix°, total sugars, reducing sugars, nonreducing
sugars, moisture, protein, fat, vitamin C, ash, iron,
zinc, calcium and crude fibre between control and treated fruit bars.
Further the glycemic index of papaya bar was reduced from 65 to 54
when treated with FOS and IN.
Abstract: Themain goal of this article is to find efficient
methods for elemental and molecular analysis of living
microorganisms (algae) under defined environmental conditions and
cultivation processes. The overall knowledge of chemical
composition is obtained utilizing laser-based techniques, Laser-
Induced Breakdown Spectroscopy (LIBS) for acquiring information
about elemental composition and Raman Spectroscopy for gaining
molecular information, respectively. Algal cells were suspended in
liquid media and characterized using their spectra. Results obtained
employing LIBS and Raman Spectroscopy techniques will help to
elucidate algae biology (nutrition dynamics depending on cultivation
conditions) and to identify algal strains, which have the potential for
applications in metal-ion absorption (bioremediation) and biofuel
industry. Moreover, bioremediation can be readily combined with
production of 3rd generation biofuels. In order to use algae for
efficient fuel production, the optimal cultivation parameters have to
be determinedleading to high production of oil in selected
cellswithout significant inhibition of the photosynthetic activity and
the culture growth rate, e.g. it is necessary to distinguish conditions
for algal strain containing high amount of higher unsaturated fatty
acids. Measurements employing LIBS and Raman Spectroscopy were
utilized in order to give information about alga Trachydiscusminutus
with emphasis on the amount of the lipid content inside the algal cell
and the ability of algae to withdraw nutrients from its environment
and bioremediation (elemental composition), respectively. This
article can serve as the reference for further efforts in describing
complete chemical composition of algal samples employing laserablation
techniques.
Abstract: In order to Study the efficacy application of green
manure as chickpea pre plant, field experiments were carried out in
2007 and 2008 growing seasons. In this research the effects of
different strategies for soil fertilization were investigated on grain
yield and yield component, minerals, organic compounds and
cooking time of chickpea. Experimental units were arranged in splitsplit
plots based on randomized complete blocks with three
replications. Main plots consisted of (G1): establishing a mixed
vegetation of Vicia panunica and Hordeum vulgare and (G2):
control, as green manure levels. Also, five strategies for obtaining the
base fertilizer requirement including (N1): 20 t.ha-1 farmyard manure;
(N2): 10 t.ha-1 compost; (N3): 75 kg.ha-1 triple super phosphate;
(N4): 10 t.ha-1 farmyard manure + 5 t.ha-1 compost and (N5): 10 t.ha-1
farmyard manure + 5 t.ha-1 compost + 50 kg.ha-1 triple super
phosphate were considered in sub plots. Furthermoree four levels of
biofertilizers consisted of (B1): Bacillus lentus + Pseudomonas
putida; (B2): Trichoderma harzianum; (B3): Bacillus lentus +
Pseudomonas putida + Trichoderma harzianum; and (B4): control
(without biofertilizers) were arranged in sub-sub plots. Results
showed that integrating biofertilizers (B3) and green manure (G1)
produced the highest grain yield. The highest amounts of yield were
obtained in G1×N5 interaction. Comparison of all 2-way and 3-way
interactions showed that G1N5B3 was determined as the superior
treatment. Significant increasing of N, P2O5, K2O, Fe and Mg content
in leaves and grains emphasized on superiority of mentioned
treatment because each one of these nutrients has an approved role in
chlorophyll synthesis and photosynthesis abilities of the crops. The
combined application of compost, farmyard manure and chemical
phosphorus (N5) in addition to having the highest yield, had the best
grain quality due to high protein, starch and total sugar contents, low
crude fiber and reduced cooking time.
Abstract: Hydrogen diffusion is the main problem for corrosion fatigue in corrosive environment. In order to analyze the phenomenon, it is needed to understand their behaviors specially the hydrogen behavior during the diffusion. So, Hydrogen embrittlement and prediction its behavior as a main corrosive part of the fractions, needed to solve combinations of different equations mathematically. The main point to obtain the equation, having knowledge about the source of causing diffusion and running the atoms into materials, called driving force. This is produced by either gradient of electrical or chemical potential. In this work, we consider the gradient of chemical potential to obtain the property equation. In diffusion of atoms, some of them may be trapped but, it could be ignorable in some conditions. According to the phenomenon of hydrogen embrittlement, the thermodynamic and chemical properties of hydrogen are considered to justify and relate them to fracture mechanics. It is very important to get a stress intensity factor by using fugacity as a property of hydrogen or other gases. Although, the diffusive behavior and embrittlement event are common and the same for other gases but, for making it more clear, we describe it for hydrogen. This considering on the definite gas and describing it helps us to understand better the importance of this relation.
Abstract: Chromite is one of the principal ore of chromium in which the metal exists as a complex oxide (FeO.Cr2O3).The prepared chromite can be widely used as refractory in high temperature applications. This study describes the use of local chromite ore as refractory material. To study the feasibility of local chromite, chemical analysis and refractoriness are firstly measured. To produce chromite refractory brick, it is pressed under a press of 400 tons, dried and fired at 1580°C for fifty two hours. Then, the standard properties such as cold crushing strength, apparent porosity, apparent specific gravity, bulk density and water absorption that the chromite brick should possess were measured. According to the results obtained, the brick made by local chromite ore was suitable for use as refractory brick.
Abstract: Jatropha curcas stem was analyzed for chemical
compositions: 19.11% pentosan, 42.99% alphacellulose and 24.11%
lignin based on dry weight of 100-g raw material. The condition to
fractionate cellulose, hemicellulose and lignin in J. curcas stem using
steam explosion was optimized. The procedure started from cutting J.
curcas stem into small pieces and soaked in water for overnight.
After that, they were steam exploded at 214 °C and 21 kg/cm2 for 5
min. The obtained hydrolysate contained 1.55 g/L ferulic acid which
after that was used as substrate for vanillin production by Aspergillus
niger and Pycnoporus cinnabarinus in one-step process. The
maximum 0.65 g/L of vanillin were obtained with the conversion rate
of 45.2% based on the initial ferulic acid.
Abstract: A numerical study on the effect of side-dump angle on
fuel droplets sizing and effective mass fraction have been
investigated in present paper. The mass of fuel vapor inside the
flammability limit is named as the effective mass fraction. In the first
step we have considered a side-dump combustor with dump angle of
0o (acrossthe cylinder) and by increasing the entrance airflow velocity
from 20 to 30, 40 and 50 (m/s) respectively, the mean diameter of
fuel droplets sizing and effective mass fraction have been studied.
After this step, we have changed the dump angle from 0o to 30o,45o
and finally 60o in direction of cylinderand also we have increased the
entrance airflow velocity from 20 up to 50 (m/s) with the amount of
growth of 10(m/s) in each step, to examine its effects on fuel droplets
sizing as well as effective mass fraction. With rise of entrance airflow
velocity, these calculations are repeated in each step too. The results
show, with growth of dump-angle the effective mass fraction has
been decreased and the mean diameter of droplets sizing has been
increased. To fulfill the calculations a modified version of KIVA-3V
code which is a transient, three-dimensional, multiphase,
multicomponent code for the analysis of chemically reacting flows
with sprays, is used.
Abstract: The freezing point of milk is in important indicator of
the milk quality. The freezing point of milk is determined primarily
to prove milk adulteration with water and to determine the amount of
water in it. Chemical composition and properties of milk, thermal
treatment and presence of any substance can influence freezing point
of product. There are different substances, which can be added to
milk with main purpose to prolong shelf-life of raw milk. There are
detergent, preservatives, formaldehyde, hydrogen peroxide,
antibiotics, sodium carbonate, and hydrogen peroxide. Therefore the
aim of the present study was to determine freezing point of milk,
skimmed milk, pasteurized milk and milk with different substances
(formaldehyde, antibiotics, sodium carbonate, hydrogen peroxide,
disinfectant, and detergent) in different concentrations. The thermal
treatment and different undesirable substances presence in milk have
significant influence on freezing point of it.
Abstract: The deposition of diamond films on a Si3N4 substrate
is an attractive technique for industrial applications because of the
excellent properties of diamond. Pretreatment of substrate is very
important prior to diamond deposition to promote nucleation and
adhesion between coating and substrate. Deposition of
nanocrystalline diamonds films on silicon nitride substrate have been
carried out by HF-CVD technique using mixture of methane and
hydrogen gases. Different pretreatment of substrate including
chemical etching consists of hot acid etching and basic etching and
mechanical etching were used to study the quality of diamond formed
on the substrate. The structure and morphology of diamond coating
have been studied using X-ray Diffraction (XRD) and Scanning
Electron Microscope (SEM) while diamond film quality has been
characterized using Raman spectroscopy. AFM was used to
investigate the effect of chemical etching and mechanical
pretreatment on the surface roughness of the substrates and the
resultant morphology of nanocrystalline diamond. It was found that
diamond film deposited on as-received, basic etched and grinded
substrate shows the morphology of cauliflower while blasted and
acidic etched substrates produce smooth, continuous diamond film.
However, the Raman investigation did not show any deviation in
quality of diamond film for any pretreatment.
Abstract: Overhead electrical insulators form an important link in an electric power system. Along with the traditional insulators (i.e. glass and porcelain, etc) presently the polymeric insulators are also used world widely. These polymeric insulators are very sensitive to various environmental parameters such temperature, environmental pollution, UV-radiations, etc. which seriously effect their electrical, chemical and hydrophobic properties. The UV radiation level in the central region of Saudi Arabia is high as compared to the IEC standard for the accelerated aging of the composite insulators. Commonly used suspension type of composite EPDM (Ethylene Propylene Diene Monomer) insulator was subjected to accelerated stress aging as per modified IEC standard simulating the inland arid deserts atmospheric condition and also as per IEC-61109 standard. The hydrophobic characteristics were studied by measuring the contact angle along the insulator surface before and after the accelerated aging of the samples. It was found that EPDM insulator loses it hydrophobic properties proportional to the intensity of UV irradiations and its rate of recovery is also very low as compared to Silicone Rubber insulator.KeywordsEPDM, composite insulators, accelerated aging, hydrophobicity, contact angle.
Abstract: Enzymatic hydrolysis is one of the major steps involved in the conversion from sugarcane bagasse to yield ethanol. This process offers potential for yields and selectivity higher, lower energy costs and milder operating conditions than chemical processes. However, the presence of some factors such as lignin content, crystallinity degree of the cellulose, and particle sizes, limits the digestibility of the cellulose present in the lignocellulosic biomasses. Pretreatment aims to improve the access of the enzyme to the substrate. In this study sugarcane bagasse was submitted chemical pretreatment that consisted of two consecutive steps, the first with dilute sulfuric acid (1 % (v/v) H2SO4), and the second with alkaline solutions with different concentrations of NaOH (1, 2, 3 and 4 % (w/v)). Thermal Analysis (TG/ DTG and DTA) was used to evaluate hemicellulose, cellulose and lignin contents in the samples. Scanning Electron Microscopy (SEM) was used to evaluate the morphological structures of the in natura and chemically treated samples. Results showed that pretreatments were effective in chemical degradation of lignocellulosic materials of the samples, and also was possible to observe the morphological changes occurring in the biomasses after pretreatments.
Abstract: This article reports on the studies of porous GaN prepared by ultra-violet (UV) assisted electrochemical etching in a solution of 4:1:1 HF: CH3OH:H2O2 under illumination of an UV lamp with 500 W power for 10, 25 and 35 minutes. The optical properties of porous GaN sample were compared to the corresponding as grown GaN. Porosity induced photoluminescence (PL) intensity enhancement was found in these samples. The resulting porous GaN displays blue shifted PL spectra compared to the as-grown GaN. Appearance of the blue shifted emission is correlated with the development of highly anisotropic structures in the morphology. An estimate of the size of the GaN nanostructure can be obtained with the help of a quantized state effective mass theory.
Abstract: The protection of groundwater resources is the great
important many semiarid and arid environments. Baghan watershed
is located in the north of Kangan in the Boshehr province in Iran. The
groundwater resources have a vital role in supplying agricultural,
drinking, domestic and industrial water demand in Baghan
watershed. For our investigation into the water quality we collected
30 samples to chemical and physical analysis. The result showed the
marl and evaporation deposits that contain anhydrite and gypsum is
the main source of groundwater pollution, and one part of the
groundwater was polluted by oil and gas industrial. Another part of
the groundwater was contaminated by urban waste water. The
electrical conductivity and captions and anions increased around of
towns and gas refinery. Although the negative impact of untreated
domestic wastewater is relatively low but the results showed strongly
the negative impact of wastewater refinery is very considerable. This
negative impact increased in downstream due to shallow aquifer.
Additionally, the agents that adversely affect the quality of
groundwater come from a variety of sources, including geology,
domestic wastewater and the Jam refinery in Baghan watershed.
Abstract: The equilibrium process of plasma nitrogen species by
chemical kinetic reactions along various pressures is successfully
investigated. The equilibrium process is required in industrial
application to obtain the stable condition when heating up the
material for having homogenous reaction. Nitrogen species densities
is modeled by a continuity equation and extended Arrhenius form.
These equations are used to integrate the change of density over the
time. The integration is to acquire density and the reaction rate of
each reaction where temperature and time dependence are imposed.
A comparison is made with global model within pressure range of 1-
100mTorr and the temperature of electron is set to be higher than
other nitrogen species. The results shows that the chemical kinetic
model only agrees for high pressure because of no power imposed;
while the global model considers the external power along the
pressure range then the electron and nitrogen species give highly
quantity densities by factor of 3 to 5.
Abstract: In-situ chemical oxidation (ISCO) has been widely
used for source zone remediation of Dense Nonaqueous Phase
Liquids (DNAPLs) in subsurface environments. DNAPL source
zones for karst aquifers are generally located in epikarst where the
DNAPL mass is trapped either in karst soil or at the regolith contact
with carbonate bedrock. This study aims to investigate the
performance of oxidation of residual trichloroethylene found in such
environments by potassium permanganate. Batch and flow cell
experiments were conducted to determine the kinetics and the mass
removal rate of TCE. pH change, Cl production, TCE and MnO4
destruction were monitored routinely during experiments. Nonreactive
tracer tests were also conducted prior and after the oxidation
process to determine the influence of oxidation on flow conditions.
The results show that oxidant consumption rate of the calcareous
epikarst soil was significant and the oxidant demand was determined
to be 20 g KMnO4/kg soil. Oxidation rate of residual TCE (1.26x10-3
s-1) was faster than the oxidant consumption rate of the soil (2.54 -
2.92x10-4 s-1) at only high oxidant concentrations (> 40 mM
KMnO4). Half life of TCE oxidation ranged from 7.9 to 10.7 min.
Although highly significant fraction of residual TCE mass in the
system was destroyed by permanganate oxidation, TCE
concentration in the effluent remained above its MCL. Flow
interruption tests indicate that efficiency of ISCO was limited by the
rate of TCE dissolution and the rate-limited desorption of TCE. The
residence time and the initial concentration of the oxidant in the
source zone also controlled the efficiency of ISCO in epikarst.
Abstract: Nano fibers produced by electrospinning are of industrial and scientific attention due to their special characteristics such as long length, small diameter and high surface area. Applications of electrospun structures in nanotechnology are included tissue scaffolds, fibers for drug delivery, composite reinforcement, chemical sensing, enzyme immobilization, membrane-based filtration, protective clothing, catalysis, solar cells, electronic devices and others. Many polymer and ceramic precursor nano fibers have been successfully electrospun with diameters in the range from 1 nm to several microns. The process is complex so that fiber diameter is influenced by various material, design and operating parameters. The objective of this work is to apply genetic algorithm on the parameters of electrospinning which have the most significant effect on the nano fiber diameter to determine the optimum parameter values before doing experimental set up. Effective factors including initial polymer concentration, initial jet radius, electrical potential, relaxation time, initial elongation, viscosity and distance between nozzle and collector are considered to determine finest diameter which is selected by user.
Abstract: Ants are fascinating creatures that demonstrate the
ability to find food and bring it back to their nest. Their ability as a
colony, to find paths to food sources has inspired the development of
algorithms known as Ant Colony Systems (ACS). The principle of
cooperation forms the backbone of such algorithms, commonly used
to find solutions to problems such as the Traveling Salesman
Problem (TSP). Ants communicate to each other through chemical
substances called pheromones. Modeling individual ants- ability to
manipulate this substance can help an ACS find the best solution.
This paper introduces a Dynamic Ant Colony System with threelevel
updates (DACS3) that enhance an existing ACS. Experiments
were conducted to observe single ant behavior in a colony of
Malaysian House Red Ants. Such behavior was incorporated into the
DACS3 algorithm. We benchmark the performance of DACS3 versus
DACS on TSP instances ranging from 14 to 100 cities. The result
shows that the DACS3 algorithm can achieve shorter distance in
most cases and also performs considerably faster than DACS.
Abstract: A novel biomass composite inspired from wood porous
structure was manufactured by impregnating vinyl monomer into
wood cellular structure under vacuum conditions, and initiating the
monomer for in situ polymerization through a thermal treatment. The
vacuum condition was studied, and the mechanical properties of the
composite were also tested. SEM observation shows that polymer
generated in the wood porous structure, and strongly interacted with
wood matrix; and the polymer content increased with vacuum value
increasing. FTIR indicates that polymer grafted onto wood matrix,
resulting chemical complex between them. The rate of monomer
loading increased with increasing vacuum value and time, accordance
with rate of polymer loading. The compression strength and modulus
of elasticity linearly increased with the increasing rate of polymer
loading. Results indicate that the novel biomass composite possesses
good mechanical properties capable of applying in the fields of
construction, traffic and so forth.