Abstract: In this work, we try to find the best setting
of Computational Fluid Dynamic solver available for the problems in
the field of supersonic internal flows. We used the supersonic air-toair
ejector to represent the typical problem in focus. There are
multiple oblique shock waves, shear layers, boundary layers
and normal shock interacting in the supersonic ejector making this
device typical in field of supersonic inner flows. Modeling of shocks
in general is demanding on the physical model of fluid, because
ordinary conservation equation does not conform to real conditions in
the near-shock region as found in many works. From these reasons,
we decided to take special care about solver setting in this article by
means of experimental approach of color Schlieren pictures and
pneumatic measurement. Fast pressure transducers were used to
measure unsteady static pressure in regimes with normal shock in
mixing chamber. Physical behavior of ejector in several regimes is
discussed. Best choice of eddy-viscosity setting is discussed on the
theoretical base. The final verification of the k-ω SST is done on the
base of comparison between experiment and numerical results.
Abstract: Recent research has shown that milk proteins can
yield bioactive peptides with opioid, mineral binding,
cytomodulatory, antihypertensive, immunostimulating, antimicrobial
and antioxidative activity in the human body. Bioactive peptides are
encrypted in milk proteins and are only released by enzymatic
hydrolysis in vivo during gastrointestinal digestion, food processing
or by microbial enzymes in fermented products. At present
significant research is being undertaken on the health effects of
bioactive peptides. A variety of naturally formed bioactive peptides
have been found in fermented dairy products, such as yoghurt, sour
milk and cheese. In particular, antihypertensive peptides have been
identified in fermented milks, whey and ripened cheese. Some of
these peptides have been commercialized in the form of fermented
milks. Bioactive peptides have the potential to be used in the
formulation of health-enhancing nutraceuticals, and as potent drugs
with well defined pharmacological effects.
Abstract: Tehran, one of the heavily-populated capitals, is
severely suffering from increasing air pollution. To show a
documented trend of such pollutants during last years, plane tree
species (Platanus orientalis) were suited to be studied as indicators,
for the species have been planted throughout the city many years
ago. Two areas (Saadatabad and Narmak districts) allotting different
contents of crowed and highly-traffic routs but the same ecological
characteristics were selected. Twelve sample individuals were cored
twice perpendicularly in each area. Tree-rings of each core were
measured by a binocular microscope and separated annually for the
last 25 years. Two heavy metals including Cd and Pb accompanied
by a mineral element (Ca) were analyzed using Hatch method. Treerings
analysis of the two areas showed different groups in term of
physiologically ability as the growths were plunged during the last
10 years in Saadatabad district and showed a slight decrease in the
same period for another studying area. In direct contrast to
decreasing growth trend in Saadatabad, all three mentioned elements
increased sharply during last 25 years in the same area. When it came
to Narmak district, the trend was completely different with
Saadatabad. There were some fluctuations in absorbing trace
elements like tree-rings widths were, yet calcium showed an upward
trend all the last 25 years. The results of the study proved the
possibility of using tree species of each region to monitor its air
pollution trends of the past, hence to depict a pollution assessment of
a populated city for last years and then to make appropriate decisions
for the future as it is well-known what the trend is. On the other
hand, risen values of calcium (as the stress-indicator element)
accompanied by increased trace elements suggests non-sustainable
state of the trees.
Abstract: Geosynthetics have proved to be suitable for
reinforced soil retaining walls. Based on the increasing uses of
geosynthetic reinforced soil systems in the regions, which bear
frequent earthquakes, the study of dynamic behavior of structures
seems necessary. Determining the reinforcement forces is; therefore,
one of the most important and main points of discussions in
designing retaining walls, by which we prevent from conservative
planning. Thus, this paper intended to investigate the effects of such
parameters as wall height, acceleration type, vertical spacing of
reinforcement, type of reinforcement and soil type on forces and
deformation through numerical modeling of the geosynthetic
reinforced soil retaining walls (GRSRW) under dynamic loading with
finite difference method by using FLAC. The findings indicate rather
positive results with each parameter.
Abstract: This work provides a practical method for the
development of rural road networks in rural areas of developing
countries. The proposed methodology enables to determine
obligatory points in the rural road network maximizing the number of
settlements that have access to basic services within a given
maximum distance. The proposed methodology is simple and
practical, hence, highly applicable to real-world scenarios, as
demonstrated in the definition of the road network for the rural areas
of Nepal.
Abstract: This paper was aimed to survey the level of awareness
of traditional grocery stores in Bangkok in these categories: location,
service quality, risk, shopping, worthwhile, shopping satisfaction, and
future shopping intention. The paper was also aimed to survey factors
influencing the decision to shop at traditional grocery stores in
Bangkok in the future. The findings revealed that consumers had a
high level of awareness of traditional grocery stores in Bangkok.
Consumers were aware that the price was higher and it was riskier to
buy goods and services at traditional grocery stores but they still had
a high level of preference to patronage traditional grocery stores. This
was due to the reasons that there was a high level of satisfaction from
the factors of the friendliness of the owner, the ability to negotiate the
price, the ability to buy on credit, free delivery, and the enjoyment to
meet with other customers in the same neighborhood.
Abstract: The sonochemical decolorization and degradation of azo dye Methyl violet using Fenton-s reagent in the presence of a high-frequency acoustic field has been investigated. Dyeing and textile effluents are the major sources of azo dyes, and are most troublesome among industrial wastewaters, causing imbalance in the eco-system. The effect of various operating conditions (initial concentration of dye, liquid-phase temperature, ultrasonic power and frequency and process time) on sonochemical degradation was investigated. Conversion was found to increase with increase in initial concentration, temperature, power level and frequency. Both horntype and tank-type sonicators were used, at various power levels (250W, 400W and 500W) for frequencies ranging from 20 kHz - 1000 kHz. A 'Process Intensification' parameter PI, was defined to quantify the enhancement of the degradation reaction by ultrasound when compared to control (i.e., without ultrasound). The present work clearly demonstrates that a high-frequency ultrasonic bath can be used to achieve higher process throughput and energy efficiency at a larger scale of operation.
Abstract: This paper describes topic of computer simulation with regard to the ground movement above an underground mine. Simulation made with software package ADINA for nonlinear elastic-plastic analysis with finite elements method. The one of representative profiles from Mine 'Stara Jama' in Zenica has been investigated. A collection and selection of both geo-mechanical data and geometric parameters of the mine was necessary for performing these simulations. Results of estimation have been compared with measured values (vertical displacement of surface), and then simulation performed with assumed dynamic and dimensions of excavation, over a period of time. Results are presented with bitmaps and charts.
Abstract: To produce sugar and ethanol, sugarcane processing
generates several agricultural residues, being straw and bagasse is
considered as the main among them. And what to do with this
residues has been subject of many studies and experiences in an
industry that, in recent years, highlighted by the ability to transform
waste into valuable products such as electric power. Cellulose is the
main component of these materials. It is the most common organic
polymer and represents about 1.5 x 1012 tons of total production of
biomass per year and is considered an almost inexhaustible source of
raw material. Pretreatment with mineral acids is one of the most
widely used as stage of cellulose extraction from lignocellulosic
materials for solubilizing most of the hemicellulose content. This
study had as goal to find the best reaction time of sugarcane bagasse
pretreatment with sulfuric acid in order to minimize the losses of
cellulose concomitantly with the highest possible removal of
hemicellulose and lignin. It was found that the best time for this
reaction was 40 minutes, in which it was reached a loss of
hemicelluloses around 70% and lignin and cellulose, around 15%.
Over this time, it was verified that the cellulose loss increased and
there was no loss of lignin and hemicellulose.
Abstract: One of the efficient factors in comprehensive
development of an area is to provide water sources and on the other
hand the appropriate management of them. Population growth and
nourishment security for such a population necessitate the
achievement of constant development besides the reforming of
traditional management in order to increase the profit of sources; In
this case, the constant exploitation of sources for the next generations
will be considered in this program. The achievement of this
development without the consideration and possibility of water
development will be too difficult. Zayanderood basin with 41500
areas in square kilometers contains 7 sub-basins and 20 units of
hydrologic. In this basin area, from the entire environment
descending, just a small part will enter into the river currents and the
rest will be out of efficient usage by various ways. The most
important surface current of this basin is Zayanderood River with
403 kilometers length which is originated from east slopes of Zagros
mount and after draining of this basin area it will enter into
Gaavkhooni pond. The existence of various sources and
consumptions of water in Zayanderood basin, water transfer of the
other basin areas into this basin, of course the contradiction between
the upper and lower beneficiaries, the existence of worthwhile
natural ecosystems such as Gaavkhooni swamp in this basin area and
finally, the drought condition and lack of water in this area all
necessitate the existence of comprehensive management of water
sources in this central basin area of Iran as this method is a kind of
management which considers the development and the management
of water sources as an equilibrant way to increase the economical
and social benefits. In this study, it is tried to survey the network of
surface water sources of basin in upper and lower sections; at the
most, according to the difficulties and deficiencies of an efficient
management of water sources in this basin area, besides the
difficulties of water draining and the destructive phenomenon of
flood-water, the appropriate guidelines according to the region
conditions are presented in order to prevent the deviation of water in
upper sections and development of regions in lower sections of
Zayanderood dam.
Abstract: The purpose of this study was to determine the most satisfying and frustrating aspects of ICT (Information and Communications Technologies) teaching in Turkish schools. Another aim was to compare these aspects based-on ICT teachers- selfefficacy. Participants were 119 ICT teachers from different geographical areas of Turkey. Participants were asked to list salient satisfying and frustrating aspects of ICT teaching, and to fill out the Self-Efficacy Scale for ICT Teachers. Results showed that the high self-efficacy teachers listed more positive and negative aspects of ICT teaching then did the low self-efficacy teachers. The satisfying aspects of ICT teaching were the dynamic nature of ICT subject, higher student interest, having opportunity to help other subject teachers, and lecturing in well-equipped labs, whereas the most frequently cited frustrating aspects of ICT teaching were ICT-related extra works of schools and colleagues, shortages of hardware and technical problems, indifferent students, insufficient teaching time, and the status of ICT subject in school curriculum. This information could be useful in redesigning ICT teachers- roles and responsibilities as well as job environment in schools.
Abstract: It has been shown that a load discontinuity at the end of
an impulse will result in an extra impulse and hence an extra amplitude
distortion if a step-by-step integration method is employed to yield the
shock response. In order to overcome this difficulty, three remedies
are proposed to reduce the extra amplitude distortion. The first remedy
is to solve the momentum equation of motion instead of the force
equation of motion in the step-by-step solution of the shock response,
where an external momentum is used in the solution of the momentum
equation of motion. Since the external momentum is a resultant of the
time integration of external force, the problem of load discontinuity
will automatically disappear. The second remedy is to perform a single
small time step immediately upon termination of the applied impulse
while the other time steps can still be conducted by using the time step
determined from general considerations. This is because that the extra
impulse caused by a load discontinuity at the end of an impulse is
almost linearly proportional to the step size. Finally, the third remedy
is to use the average value of the two different values at the integration
point of the load discontinuity to replace the use of one of them for
loading input. The basic motivation of this remedy originates from the
concept of no loading input error associated with the integration point
of load discontinuity. The feasibility of the three remedies are
analytically explained and numerically illustrated.
Abstract: CO2 miscible displacement is not feasible in many oil fields due to high reservoir temperature as higher pressure is required to achieve miscibility. The miscibility pressure is far higher than the formation fracture pressure making it impossible to have CO2 miscible displacement. However, by using oleophilic chemicals, minimum miscibility pressure (MMP) could be lowered. The main objective of this research is to find the best oleophilic chemical in MMP reduction using slim-tube test and Vanishing Interfacial Tension (VIT) The chemicals are selected based on the characteristics that it must be oil soluble, low water solubility, have 4 – 8 carbons, semi polar, economical, and safe for human operation. The families of chemicals chosen are carboxylic acid, alcohol, and ketone. The whole experiment would be conducted at 100°C and the best chemical is said to be effective when it is able to lower CO2-crude oil MMP the most. Findings of this research would have great impact to the oil and gas industry in reduction of operation cost for CO2EOR which is applicable to both onshore and offshore operation.
Abstract: Wind is among the potential energy resources which
can be harnessed to generate wind energy for conversion into
electrical power. Due to the variability of wind speed with time and
height, it becomes difficult to predict the generated wind energy more
optimally. In this paper, an attempt is made to establish a
probabilistic model fitting the wind speed data recorded at
Makambako site in Tanzania. Wind speeds and direction were
respectively measured using anemometer (type AN1) and wind Vane
(type WD1) both supplied by Delta-T-Devices at a measurement
height of 2 m. Wind speeds were then extrapolated for the height of
10 m using power law equation with an exponent of 0.47. Data were
analysed using MINITAB statistical software to show the variability
of wind speeds with time and height, and to determine the underlying
probability model of the extrapolated wind speed data. The results
show that wind speeds at Makambako site vary cyclically over time;
and they conform to the Weibull probability distribution. From these
results, Weibull probability density function can be used to predict
the wind energy.
Abstract: Carbon Capture & Storage (CCS) is one of the various
methods that can be used to reduce the carbon footprint of the
energy sector. This paper focuses on the absorption of CO2 from
flue gas using packed columns, whose efficiency is highly dependent
on the structure of the liquid films within the column. To study the
characteristics of liquid films a CFD solver, OpenFOAM is utilised
to solve two-phase, isothermal film flow using the volume-of-fluid
(VOF) method. The model was validated using existing experimental
data and the Nusselt theory. It was found that smaller plate inclination
angles, with respect to the horizontal plane, resulted in larger wetted
areas on smooth plates. However, only a slight improvement in
the wetted area was observed. Simulations were also performed
using a ridged plate and it was observed that these surface textures
significantly increase the wetted area of the plate. This was mainly
attributed to the channelling effect of the ridges, which helped to
oppose the surface tension forces trying to minimise the surface area.
Rivulet formations on the ridged plate were also flattened out and
spread across a larger proportion of the plate width.
Abstract: Camera calibration is an important step in 3D
reconstruction. Camera calibration may be classified into two major types: traditional calibration and self-calibration. However, a calibration method in using a checkerboard is intermediate between traditional calibration and self-calibration. A self
is proposed based on a square in this paper. Only a square in the planar
template, the camera self-calibration can be completed through the single view. The proposed algorithm is that the virtual circle and straight line are established by a square on planar template, and
circular points, vanishing points in straight lines and the relation
between them are be used, in order to obtain the image of the absolute
conic (IAC) and establish the camera intrinsic parameters. To make
the calibration template is simpler, as compared with the Zhang Zhengyou-s method. Through real experiments and experiments, the experimental results show that this algorithm is
feasible and available, and has a certain precision and robustness.
Abstract: The absolute Cu atoms density in Cu(2S1/22P1/2)
ground state has been measured by Resonance Optical Absorption
(ROA) technique in a DC magnetron sputtering deposition with
argon. We measured these densities under variety of operation
conditions: pressure from 0.6 μbar to 14 μbar, input power from
10W to 200W and N2 mixture from 0% to 100%. For measuring the
gas temperature, we used the simulation of N2 rotational spectra
with a special computer code. The absolute number density of Cu
atoms decreases with increasing the N2 percentage of buffer gas at
any conditions of this work. But the deposition rate, is not decreased
with the same manner. The deposition rate variation is very small
and in the limit of quartz balance measuring equipment accuracy. So
we conclude that decrease in the absolute number density of Cu
atoms in magnetron plasma has not a big effect on deposition rate,
because the diffusion of Cu atoms to the chamber volume and
deviation of Cu atoms from direct path (towards the substrate)
decreases with increasing of N2 percentage of buffer gas. This is
because of the lower mass of N2 atoms compared to the argon ones.
Abstract: Single crystals of Magnesium alloys such as Mg-1Al,
Mg-1Zn-0.5Y, Mg-3Li, and AZ31 alloys were successfully fabricated in this study by employing the modified Bridgman method. Single
crystals of pure Mg were also made in this study. To determine the exact orientation of crystals, Laue back-reflection method and pole figure measurement were carried out on each single crystal. Dimensions of single crystals were 10 mm in diameter and 120 mm in
length. Hardness and compression tests were conducted and the results
revealed that hardness and the strength strongly depended on the
orientation. The closer to basal one the orientation was, the higher hardness and compressive strength were. The effect of alloying was
not higher than that of orientation. After compressive deformation of single crystals, the orientation of the crystals was found to rotate and to be parallel to the basal orientation.
Abstract: Many commercial processes are available for the
removal of H2S from gaseous streams. The desulfurization of gas
streams using aqueous ferric sulfate solution as washing liquor is
studied. Apart from sulfur, only H2O is generated in the process, and
consequently, no waste treatment facilities are required. A distinct
advantage of the process is that the reaction of H2S with is so rapid
and complete that there remains no danger of discharging toxic waste
gas. In this study, the reactive absorption of hydrogen sulfide into
aqueous ferric sulfate solution has been studied and design
calculations for equipments have been done and effective operation
parameters on this process considered. Results show that high
temperature and low pressure are suitable for absorption reaction.
Variation of hydrogen sulfide concentration and Fe3+ concentration
with time in absorption reaction shown that the reaction of ferric
sulfate and hydrogen sulfide is first order with respect to the both
reactant. At low Fe2(SO4)3 concentration the absorption rate of H2S
increase with increasing the Fe2(SO4)3 concentration. At higher
concentration a decrease in the absorption rate was found. At higher
concentration of Fe2(SO4)3, the ionic strength and viscosity of
solution increase remarkably resulting in a decrease of solubility,
diffusivity and hence absorption rate.
Abstract: The antioxidant capability of beverage blends made from cocoa, zobo and ginger with standard antioxidant assay procedures was investigated. The DPPH (2,2-diphenyl-1- picrylhydrazyl) scavenging capacity ranged from 21.2-25.8% in comparison with GSH of 37.1%. The ferric reducing ability was highest in the zobo drink and lowest in ginger. The superoxide scavenging capacity was also highest in the zobo drink followed by the drink with alkalized cocoa. The metal chelating power decreased as the level of zobo in the blends decreases. The chelating power of zobo and ginger were significantly lower than the natural and alkalized cocoa. The 100% zobo drink inhibited linoleic acid till the fifth day while natural and alkalized cocoa as well as the blend with 50% alkalized cocoa inhibited linoleic acid greatly till the sixth day. The finding describes the potential health benefit of the phytochemical antioxidants of cocoa:zobo:ginger beverage blends.