Abstract: Highly ordered TiO2 nanotube (TNT) arrays were
fabricated onto a pre-treated titanium foil by anodic oxidation with a
voltage of 20V in phosphoric acid/sodium fluoride electrolyte. A pretreatment
of titanium foil involved washing with acetone,
isopropanol, ethanol and deionized water. Carbon doped TiO2
nanotubes (C-TNT) was fabricated 'in-situ' with the same method in
the presence of polyvinyl alcohol and urea as carbon sources. The
affects of polyvinyl alcohol concentration and oxidation time on the
composition, morphology and structure of the C-TN were studied by
FE-SEM, EDX and XRD techniques. FESEM images of the
nanotubes showed uniform arrays of C-TNTs. The density and
microstructures of the nanotubes were greatly affected by the content
of PVA. The introduction of the polyvinyl alcohol into the electrolyte
increases the amount of C content inside TiO2 nanotube arrays
uniformly. The influence of carbon content on the photo-current of
C-TNT was investigated and the I-V profiles of the nanotubes were
established. The preliminary results indicated that the 'in-situ'
doping technique produced a superior quality nanotubes compared to
post doping techniques.
Abstract: The Platform Screen Doors improve Indoor Air Quality
(IAQ) in the subway station; however, and the air quality is degraded
in the subway tunnel. CO2 concentration and indoor particulate matter
value are high in the tunnel. The IAQ level in subway tunnel degrades
by increasing the train movements. Air-curtain installation reduces
dusts, particles and moving toxic smokes and permits traffic by
generating virtual wall. The ventilation systems of the subway tunnel
need improvements to have better air-quality. Numerical analyses
might be effective tools analyze the flowfield inside the air-curtain
installed subway tunnel. The ANSYS CFX software is used for steady
computations of the airflow inside the tunnel. The single-track subway
tunnel has the natural shaft, the mechanical shaft, and the PSDs
installed stations. The height and width of the tunnel are 6.0 m and 4.0
m respectively. The tunnel is 400 m long and the air-curtain is installed
at the top of the tunnel. The thickness and the width of the air-curtain
are 0.08 m and 4 m respectively. The velocity of the air-curtain
changes between 20 - 30 m/s. Three cases are analyzed depending on
the installing location of the air-curtain. The discharged-air through
the natural shafts increases as the velocity of the air-curtain increases
when the air-curtain is installed between the mechanical and the
natural shafts. The pollutant-air is exhausted by the mechanical and the
natural shafts and remained air is pushed toward tunnel end. The
discharged-air through the natural shaft is low when the air-curtain
installed before the natural shaft. The mass flow rate decreases in the
tunnel after the mechanical shaft as the air-curtain velocity increases.
The computational results of the air-curtain installed tunnel become
basis for the optimum design study. The air-curtain installing location
is chosen between the mechanical and the natural shafts. The velocity
of the air-curtain is fixed as 25 m/s. The thickness and the blowing
angles of the air-curtain are the design variables for the optimum
design study. The object function of the design optimization is
maximizing the discharged air through the natural shaft.
Abstract: Two freshwater fishes, Rasbora sumatrana
(Cyprinidae) and Poecilia reticulata (guppy) (Poeciliidae) were
exposed for a four-day period in the laboratory condition to a range
of copper (Cu) and cadmium (Cd) concentrations. Mortality was
assessed and median lethal concentrations (LC50) were calculated.
LC50 increased with decrease in mean exposure times for both metals.
For R. sumatrana, LC50s for 24, 48, 72 and 96 hours for Cu were
54.2, 30.3, 18.9 and 5.6 μg/L and for Cd 1440.2, 459.3, 392.3 and
101.6 μg/L respectively. For P. reticulata, LC50s for 24, 48, 72 and
96 hours for Cu were 348.9, 145.4, 61.3 and 37.9 μg/L and for Cd
8205.6, 2827.1, 405.8 and 168.1 μg/L, respectively. Results indicated
that the Cu was more toxic than Cd to both fishes (Cu>Cd) and R.
sumatrana was more sensitive than P. reticulata to the metals.
Abstract: The volume of biosolids produced in Malaysia
nowadays had increased proportionally to its population size. The end
products from the waste treatments were mounting, thus inevitable
that in the end the environment will be surrounded by the waste. This
study was conducted to investigate the suitability of biosolids to be
reused as fertilizer for non-food crop. By varying the concentration of
biosolids applied onto the soil, growth of five ornamental plant
samples were tested for eight consecutive weeks. The results show
that the pH of the soil after the addition of biosolids ranges from 6.45
to 6.56 which is suitable for the plant growth. The soil samples that
contains biosolid also show higher amount of macronutrients (N, P,
K) and the heavy metals content are significantly increased in the
plant however it does not exceed the guidelines drawn by the
Environmental Protection Agency. It is also proven that there was
only small significant different in the performance of plant growth
between biosolids and commercial fertilizer. It can be seen that
biosolids was able to perform just as well as commercial fertilizer.
Abstract: In vitro plant regeneration has been successfully obtained from basal shoot explant of Vetiveria zizanioides through indirect organogenesis. The explant was cultured in Murashige & Skoog’s (MS) media supplemented with 2,4-D, IAA, and kinetin in various concentrations. Callus was well induced in media supplemented with 2 ppm 2,4-D, 1 ppm IAA, and 1 ppm kinetin. This callus was then transferred to MS media supplemented with 1 - 5 ppm of BAP for shoot regeneration. The media supplemented with 3 ppm BAP was a suitable medium for shoot induction, as well as for shoot multiplication. Rooting was well developed in shoot following transferred to half MS media containing 0.2 ppm IBA. Plantlet was then transferred to husk charcoal for acclimatization, and almost all (90%) of plantlets were survived during acclimatization.
Abstract: Sediment formation and its transport along the river course is considered as important hydraulic consideration in river engineering. Their impact on the morphology of rivers on one hand and important considerations of which in the design and construction of the hydraulic structures on the other has attracted the attention of experts in arid and semi-arid regions. Under certain conditions where the momentum energy of the flow stream reaches a specific rate, the sediment materials start to be transported with the flow. This can usually be analyzed in two different categories of suspended and bed load materials. Sedimentation phenomenon along the waterways and the conveyance of vast volume of materials into the canal networks can potentially influence water abstraction in the intake structures. This can pose a serious threat to operational sustainability and water delivery performance in the canal networks. The situation is serious where ineffective watershed management (poor vegetation cover in the water basin) is the underlying cause of soil erosion which feeds the materials into the waterways that intern would necessitate comprehensive study. The present paper aims to present an analytical investigation of the sediment process in the waterways on one hand and estimation of the sediment load transport into the lined canals using the SHARC software on the other. For this reason, the paper focuses on the comparative analysis of the hydraulic behaviors of the Sabilli main canal that feeds the pumping station with that of the Western canal in the Greater Dezful region to identify effective factors in sedimentation and ways of mitigating their impact on water abstraction in the canal systems. The method involved use of observational data available in the Dezful Dastmashoon hydrometric station along a 6 km waterway of the Sabilli main canal using the SHARC software to estimate the suspended load concentration and bed load materials. Results showed the transport of a significant volume of sediment loads from the waterways into the canal system which is assumed to have arisen from the absence of stilling basin on one hand and the gravity flow on the other has caused serious challenges. This is contrary to what occurs in the Sabilli canal, where the design feature which incorporates a settling basin just before the pumping station is the major cause of reduced sediment load transport into the canal system.Results showed that modification of the present design features by constructing a settling basin just upstream of the western intake structure can considerably reduce the entry of sediment materials into the canal system. Not only this can result in the sustainability of the hydraulic structures but can also improve operational performance of water conveyance and distribution system, all of which are the pre-requisite to secure reliable and equitable water delivery regime for the command area.
Abstract: Laser soldering is based on applying some soldering material (albumin) onto the approximated edges of the cut and heating the solder (and the underlying tissues) by a laser beam. Endogenous and exogenous materials such as indocyanine green (ICG) are often added to solders to enhance light absorption. Gold nanoshells are new materials which have an optical response dictated by the plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes, allowing nanoshells to be tailored for particular applications. The purposes of this study was use combination of ICG and different concentration of gold nanoshells for skin tissue soldering and also to examine the effect of laser soldering parameters on the properties of repaired skin. Two mixtures of albumin solder and different combinations of ICG and gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after addition of mixtures it was irradiated by an 810nm diode laser at different power densities. The changes of tensile strength σt due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. The results showed at constant laser power density (I), σt of repaired incisions increases by increasing the concentration of gold nanoshells in solder, Ns and decreasing Vs. It is therefore important to consider the tradeoff between the scan velocity and the surface temperature for achieving an optimum operating condition. In our case this corresponds to σt =1800 gr/cm2 at I~ 47 Wcm-2, T ~ 85ºC, Ns =10 and Vs=0.3mms-1.
Abstract: The adsorption of simulated aqueous solution containing textile remazol reactive dye, namely Red 3BS by palm shell activated carbon (PSAC) as adsorbent was carried out using Response Surface Methodology (RSM). A Box-Behnken design in three most important operating variables; initial dye concentration, dosage of adsorbent and speed of impeller was employed for experimental design and optimization of results. The significance of independent variables and their interactions were tested by means of the analysis of variance (ANOVA) with 95% confidence limits. Model indicated that with the increasing of dosage and speed give the result of removal up to 90% with the capacity uptake more than 7 mg/g. High regression coefficient between the variables and the response (R-Sq = 93.9%) showed of good evaluation of experimental data by polynomial regression model.
Abstract: Titanium oxide hollow microspheres were synthesized from organic precursor titanium tetraisopropoxide (TTIP) using continuous spray pyrolysis reactor. Effects of precursor concentration, applied voltage and annealing have been investigated. It was observed that the annealing of the as-synthesized TiO2 hollow microspheres at 2500C, which had an average external diameter of 200 nm, leads to an increase in the size and also more spherical shape. The precursor concentration was found to have a direct impact on the size of the microspheres, which is also evident in the absorption spectrum. The as-prepared TiO2 hollow microspheres exhibited good photocatalytic activity for the degradation of MO.
Abstract: If a possibility distribution and a probability distribution
are describing values x of one and the same system or process
x(t), can they relate to each other? Though in general the possibility
and probability distributions might be not connected at all, we
can assume that in some particular cases there is an association linked
them.
In the presented paper, we consider distributions of bloodstream
concentrations of physiologically active substances and propose that
the probability to observe a concentration x of a substance X can be
produced from the possibility of the event X = x .
The proposed assumptions and resulted theoretical distributions
are tested against the data obtained from various panel studies of the
bloodstream concentrations of the different physiologically active
substances in patients and healthy adults as well.
Abstract: Adsorption of Toluidine blue dye from aqueous solutions onto Neem Leaf Powder (NLP) has been investigated. The surface characterization of this natural material was examined by Particle size analysis, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD). The effects of process parameters such as initial concentration, pH, temperature and contact duration on the adsorption capacities have been evaluated, in which pH has been found to be most effective parameter among all. The data were analyzed using the Langmuir and Freundlich for explaining the equilibrium characteristics of adsorption. And kinetic models like pseudo first- order, second-order model and Elovich equation were utilized to describe the kinetic data. The experimental data were well fitted with Langmuir adsorption isotherm model and pseudo second order kinetic model. The thermodynamic parameters, such as Free energy of adsorption (AG"), enthalpy change (AH') and entropy change (AS°) were also determined and evaluated.
Abstract: Commercial hydroxyapatite (HA) was reinforced by
adding 2, 5, and 10 wt % of 28.5%CaO-28.5%P2O5-38%Na2 O-
5%CaF2 based glass and then sintered. Although HA shows good
biocompatibility with the human body, its applications are limited to
non load-bearing areas and coatings due to its poor mechanical
properties. These mechanical properties can be improved
substantially with addition of glass ceramics by sintering. In this
study, the effects of sintering hydroxyapatite with above specified
phosphate glass additions are quantified. Each composition was
sintered over a range of temperatures. Scanning electron microscopy
and x-ray diffraction were used to characterize the microstructure and
phases of the composites. The density, microhardness, and
compressive strength were measured using Archimedes Principle,
Vickers Microhardness Tester (at 0.98 N), and Instron Universal
Testing Machine (cross speed of 0.5 mm/min) respectively. These
results were used to indicate which composition provided suitable
material for use in hard tissue replacement. Composites containing 10
wt % glass additions formed dense HA/TCP (tricalcium phosphate)
composite materials possessing good compressive strength and
hardness than HA. In-vitro bioactivity was assessed by evaluating
changes in pH and Ca2+ ion concentration of SBF-simulated body
fluid on immersion of these composites in it for two weeks.
Abstract: A numerical study on the influence of electroosmotic flow on analyte preconcentration by isotachophoresis ( ITP) is made. We consider that the double layer induced electroosmotic flow ( EOF) counterbalance the electrophoretic velocity and a stationary ITP stacked zones results. We solve the Navier-Stokes equations coupled with the Nernst-Planck equations to determine the local convective velocity and the preconcentration dynamics of ions. Our numerical algorithm is based on a finite volume method along with a secondorder upwind scheme. The present numerical algorithm can capture the the sharp boundaries of step-changes ( plateau mode) or zones of steep gradients ( peak mode) accurately. The convection of ions due to EOF reduces the resolution of the ITP transition zones and produces a dispersion in analyte zones. The role of the electrokinetic parameters which induces dispersion is analyzed. A one-dimensional model for the area-averaged concentrations based on the Taylor-Aristype effective diffusivity is found to be in good agreement with the computed solutions.
Abstract: In Southeast Asia, during the dry season (August to
October) forest fires in Indonesia emit pollutants into the atmosphere.
For two years during this period, a total of 67 samples of 2.5 μm
particulate matters were collected and analyzed for total mass and
elemental composition with ICP - MS after microwave digestion. A
study of 60 elements measured during these periods suggest that the
concentration of most of elements, even those usually related to
crustal source, are extremely high and unpredictable during the haze
period. In By contrast, trace element concentration in non - haze
months is more stable and covers a lower range. Other unexpected
events and their effects on the findings are discussed.
Abstract: The presence of heavy metals in the environment
could constitute a hazard to food security and public health. These
can be accumulated in aquatic animals such as fish. Samples of four
popular brands of canned fish in the Iranian market (yellowfin tuna,
common Kilka, Kawakawa and longtail tuna) were analyzed for level
of Cr after wet digestion with acids using graphite furnace atomic
absorption spectrophotometry. The mean concentrations for Cr in the
different brands were: 2.57, 3.24, 3.16 and 1.65 μg/g for brands A, B,
C and D respectively. Significant differences were observed in the Cr
levels between all of the different brands of canned fish evaluated in
this study. The Cr concentrations for the varieties of canned fishes
were generally within the FAO/WHO, U.S. FDA and U.S. EPA
recommended limits for fish.
Abstract: Palm shell obtained from coastal part of southern
India was studied for the removal for the adsorption of Hg (II) ions.
Batch adsorption experiments were carried out as a function of pH,
concentration of Hg (II) ions, time, temperature and adsorbent dose.
Maximum removal was seen in the range pH 4.0- pH 7.0. The palm
shell powder used as adsorbent was characterized for its surface area,
SEM, PXRD, FTIR, ion exchange capacity, moisture content, and
bulk density, soluble content in water and acid and pH. The
experimental results were analyzed using Langmuir I, II, III, IV and
Freundlich adsorption isotherms. The batch sorption kinetics was
studied for the first order reversible reaction, pseudo first order;
pseudo second order reaction and the intra-particle diffusion reaction.
The biomass was successfully used for removal Hg (II) from
synthetic and industrial effluents and the technique appears
industrially applicable and viable.
Abstract: Controlled release urea has become popular in agricultural industry as it helps to solve environmental issues and increase crop yield. Recently biomass was identified to replace the polymer used as a coating material in the conventional coated urea. In this paper spreading and contact angle of biomass droplet (lignin, cellulose and clay) on urea surface are investigated experimentally. There were two tests were conducted, sessile drop for contact angle measurement and pendant drop for contact angle measurement. A different concentration of biomass droplet was released from 30 mm above a substrate. Glass was used as a controlled substrate. Images were recorded as soon as the droplet impacted onto the urea before completely adsorb into the urea. Digitized droplets were then used to identify the droplet-s surface tension and contact angle. There is large difference observed between the low surface tension and high surface tension liquids, where the wetting and spreading diameter is higher for lower surface tension. From the contact angle results, the data showed that the biomass coating films were possible as wetting liquid (θ < 90º). Contact angle of biomass coating material gives good indication for the wettablity of a liquid on urea surface.
Abstract: Catalytic converters are used for minimizing the release of pollutants to the atmosphere. It is during the warm-up period that hydrocarbons are seen to be released in appreciable quantities from these converters. In this paper the conversion of a fast oxidizing hydrocarbon propylene is analysed using two numerical methods. The quasi steady state method assumes the accumulation terms to be negligible in the gas phase mass and energy balance equations, however this term is present in the solid phase energy balance. The unsteady state model accounts for the accumulation term to be present in the gas phase mass and energy balance and in the solid phase energy balance. The results derived from the two models for gas concentration, gas temperature and solid temperature are compared.
Abstract: Levan, an exopolysaccharide, was produced by
Microbacterium laevaniformans and its yield was characterized as a
function of concentrations of date syrup, sucrose and the fermentation
time. The optimum condition for levan production from sucrose was
at concentration of 20% sucrose for 48 h and for date syrup was 25%
for 48 h. The results show that an increase in fermentation time
caused a decrease in the levan production at all concentrations of date
syrup tested. Under these conditions after 48 h in sucrose medium,
levan production reached 48.9 g/L and for date syrup reached 10.48
g/L . The effect of pH on the yield of the purified levan was examined
and the optimum pH for levan production was determined to be 6.0.
Levan was composed mainly of fructose residues when analyzed by
TLC and FT-IR spectroscopy. Date syrup is a cheap substrate widely
available in Iran and has potential for levan production. The thermal
stability of levan was assessed by Thermo Gravimetric Analysis
(TGA) that revealed the onset of decomposition near to 49°C for the
levan produced from sucrose and 51°C for the levan from date syrup.
DSC results showed a single Tg at 98°C for levan produced from
sucrose and 206 °C for levan from date syrup.
Abstract: 17α-ethynylestradiol (EE2) is a synthetic estrogen
used as a key ingredient in an oral contraceptives pill. EE2 is an
endocrine disrupting compound, high in estrogenic potency.
Although EE2 exhibits low degree of biodegradability with common
microorganisms in wastewater treatment plants (WWTPs), this
compound can be biotransformed by ammonia-oxidizing bacteria
(AOB) via a co-metabolism mechanism in WWTPs. This study
aimed to investigate the effect of real wastewater on
biotransformation of EE2 by AOB. A preliminary experiment on the
effect of nitrite and pH levels on abiotic transformation of EE2
suggested that the abiotic transformation occurred at only pH