Abstract: In this research, thorium dioxide mesoporous
nanocrystalline powder was synthesized through the sol-gel method
using hydrated thorium nitrate and ammonium hydroxide as starting
materials and Triton X100 as surfactant. ThO2 gel was characterized
by thermogravimetric (TGA), and prepared ThO2 powder was
subjected to scanning electron microscopy (SEM), X-ray diffraction
(XRD), and Brunauer-Emett-Teller (BET) analyses studies. Detailed
analyses show that prepared powder consisted of phase with the
space group Fm3m of thoria and its crystalline size was 12.6 nm. The
thoria possesses 16.7 m2/g surface area and the pore volume and size
calculated to be 0.0423 cc/g and 1.947 nm, respectively.
Abstract: Expansive soils are often encountered in many parts
of the world, especially in arid and semi-arid fields. Such kind of
soils, generally including active clay minerals in low water content,
enlarge in volume by absorbing the water through the surface and
cause a great harm to the light structures such as channel coating,
roads and airports. The expansive soils were encountered on the path
of Apa-Hotamış conveyance channel belonging to the State
Hydraulic Works in the region of Konya. In the research done in this
area, it is predicted that the soil has a swollen nature and the soil
should be filled with proper granular equipments by digging the
ground to 50-60 cm. In this study, for purpose of helping the other
research to be done in the same area, it is thought that instead of
replacing swollen soil with the granular soil, by stabilizing it with
polypropylene fiber and using it its original place decreases effect of
swelling percent, in this way the cost will be decreased. Therefore,
laboratory tests were conducted to study the effects of polypropylene
fiber on swelling characteristics of expansive soil. Test results
indicated that inclusion of fiber reduced swell percent of expansive
soil. As the fiber content increased, the unconfined compressive
strength was increased. Finally, it can be said that stabilization of
expansive soils with polypropylene fiber is an effective method.
Abstract: The objective of this study was to evaluate the
effects of calving season on the production and economic efficiency
of dairy farms in Egypt. Our study was performed at dairy
production farms in the Alexandria, Behera, and Kafr El-Sheikh
provinces of Egypt from summer 2010 to winter 2013. The
randomly selected dairy farms had herds consisting of Baladi,
Holstein-Friesian, or cross-bred (Baladi × Holstein-Friesian) cows.
The data were collected from production records and responses to a
structured questionnaire. The average total return differed
significantly (P < 0.05) between the different cattle breeds and
calving seasons. The average total return was highest for the
Holstein- Friesian cows that calved in the winter (29106.42
EGP/cow/year), and it was lowest for Baladi cows that calved in the
summer (12489.79 EGP/cow/year). Differences in total returns
between the cows that calved in the winter or summer or between
the foreign and native breeds, as well as variations in calf prices,
might have contributed to the differences in milk yield. The average
net profit per cow differed significantly (P < 0.05) between the cattle
breeds and calving seasons. The average net profit values for the
Baladi cows that calved in the winter or summer were 2413 and
2994.96 EGP/cow/year, respectively, and those for the Holstein-
Friesian cows were 10744.17 and 7860.56 EGP/cow/year,
respectively, whereas those for the cross-bred cows were 10174.86
and 7571.33 EGP/cow/year, respectively. The variations in net profit
might have resulted from variation in the availability or price of feed
materials, milk prices, or sales volumes. Our results show that the
breed and calving season of dairy cows significantly affected the
economic efficiency of dairy farms in Egypt. The cows that calved
in the winter produced more milk than those that calved in the
summer, which may have been the result of seasonal influences,
such as temperature, humidity, management practices, and the type
of feed or green fodder available.
Abstract: This study presents three different approaches to
estimate bubble point pressures for the binary system of CO2 and
ethyl palmitate fatty acid ethyl ester. The first method involves the
Peng-Robinson (PR) Equation of State (EoS) with the conventional
mixing rule of Van der Waals. The second approach involves the PR
EOS together with the Wong Sandler (WS) mixing rule, coupled with
the UNIQUAC GE model. In order to model the bubble point
pressures with this approach, the volume and area parameter for ethyl
palmitate were estimated by the Hansen group contribution method.
The last method involved the Peng-Robinson, combined with the
Wong-Sandler method, but using NRTL as the GE model. Results
using the Van der Waals mixing rule clearly indicated that this
method has the largest errors among all three methods, with errors in
the range of 3.96-6.22%. The PR-WS-UNIQUAC method exhibited
small errors, with average absolute deviations between 0.95 to 1.97
percent. The PR-WS-NRTL method led to the least errors, where
average absolute deviations ranged between 0.65-1.7%.
Abstract: In this paper comprehensive studies have been carried
out for the design optimization of a waste heat recovery system for
effectively utilizing the domestic air conditioner heat energy for
producing hot water. Numerical studies have been carried for the
geometry optimization of a waste heat recovery system for domestic
air conditioners. Numerical computations have been carried out using
a validated 2d pressure based, unsteady, 2nd-order implicit, SST k-ω
turbulence model. In the numerical study, a fully implicit finite
volume scheme of the compressible, Reynolds-Averaged, Navier-
Stokes equations is employed. At identical inflow and boundary
conditions various geometries were tried and effort has been taken for
proposing the best design criteria. Several combinations of pipe line
shapes viz., straight and spiral with different number of coils for the
radiator have been attempted and accordingly the design criteria has
been proposed for the waste heat recovery system design. We have
concluded that, within the given envelope, the geometry optimization
is a meaningful objective for getting better performance of waste heat
recovery system for air conditioners.
Abstract: This paper represents an experimental study of LPG
diffusion flame at elevated preheated air temperatures. The flame is
stabilized in a vertical water-cooled combustor by using air swirler. An
experimental test rig was designed to investigate the different
operating conditions. The burner head is designed so that the LPG fuel
issued centrally and surrounded by the swirling air issues from an air
swirler. There are three air swirlers having the same dimensions but
having different blade angles to give different swirl numbers of 0.5,
0.87 and 1.5. The combustion air was heated electrically before
entering the combustor up to a temperature about 500 K. Five air to
fuel mass ratios of 15, 20, 30, 40 and 50 were also studied. The effect
of preheated air temperature, swirl number and air to fuel mass ratios
on the temperature maps, visible flame length, high temperature region
(size) and exhaust species concentrations are studied. Some results
show that as the preheated air temperature increases, the volume of
high temperature region also increased but the flame length decreased.
Increasing the preheated air temperature, EINOx, EICO2 and EIO2
increased, while EICO decreased. Increasing the preheated air
temperature from 300 to 500 K, for all air swirl numbers used, the
highest increase in EINOx, EICO2 and EIO2 are 141, 4 and 65%,
respectively.
Abstract: Ceramic Waste Aggregates (CWAs) were made from
electric porcelain insulator wastes supplied from an electric power
company, which were crushed and ground to fine aggregate sizes. In
this study, to develop the CWA mortar as an eco–efficient, ground
granulated blast–furnace slag (GGBS) as a Supplementary
Cementitious Material (SCM) was incorporated. The water–to–binder
ratio (W/B) of the CWA mortars was varied at 0.4, 0.5, and 0.6. The
cement of the CWA mortar was replaced by GGBS at 20 and 40% by
volume (at about 18 and 37% by weight). Mechanical properties of
compressive and splitting tensile strengths, and elastic modulus were
evaluated at the age of 7, 28, and 91 days. Moreover, the chloride
ingress test was carried out on the CWA mortars in a 5.0% NaCl
solution for 48 weeks. The chloride diffusion was assessed by using an
electron probe microanalysis (EPMA). To consider the relation of the
apparent chloride diffusion coefficient and the pore size, the pore size
distribution test was also performed using a mercury intrusion
porosimetry at the same time with the EPMA. The compressive
strength of the CWA mortars with the GGBS was higher than that
without the GGBS at the age of 28 and 91 days. The resistance to the
chloride ingress of the CWA mortar was effective in proportion to the
GGBS replacement level.
Abstract: In recent decades, particulate matter (PM10) have
received much attention due to its potential adverse health impact and
the subsequent need to better control or regulate these pollutants.
The aim of this paper is focused on study risk assessment of PM10
in four different districts (Shebikah, Masfalah, Aziziyah, Awali) in
Makkah, Saudi Arabia during the period from 1 Ramadan 1434 AH -
27 Safar 1435 AH. Samples were collected by using Low Volume
Sampler (LVS Low Volume Sampler) device and filtration method
for estimating the total concentration of PM10.
The study indicated that the mean PM10 concentrations were 254.6
(186.1 - 343.2) μg/m3 in Shebikah, 184.9 (145.6 - 271.4) μg/m3 in
Masfalah, 162.4 (92.4-253.8) μg/m3 in Aziziyah, and 56.0 (44.5 -
119.8) μg/m3 in Awali. These values did not exceed the permissible
limits in PME (340 μg/m3 as daily average). Furthermore, health
assessment is carried out using AirQ2.2.3 model to estimate the
number of hospital admissions due to respiratory diseases. The
cumulative number of cases per 100,000 were 1534 (18-3050 case),
which lower than that recorded in the United States, Malaysia. The
concentration response coefficient was 0.49 (95% CI 0.05 - 0.70) per
10 μg/m3 increase of PM10.
Abstract: This paper presents the design and fabrication of a
novel piezoelectric actuator for a gas micro pump with check valve
having the advantages of miniature size, light weight and low power
consumption. The micro pump is designed to have eight major
components, namely a stainless steel upper cover layer, a piezoelectric
actuator, a stainless steel diaphragm, a PDMS chamber layer, two
stainless steel channel layers with two valve seats, a PDMS check
valve layer with two cantilever-type check valves and an acrylic
substrate. A prototype of the gas micro pump, with a size of 52 mm ×
50 mm × 5.0 mm, is fabricated by precise manufacturing. This device
is designed to pump gases with the capability of performing the
self-priming and bubble-tolerant work mode by maximizing the stroke
volume of the membrane as well as the compression ratio via
minimization of the dead volume of the micro pump chamber and
channel. By experiment apparatus setup, we can get the real-time
values of the flow rate of micro pump and the displacement of the
piezoelectric actuator, simultaneously. The gas micro pump obtained
higher output performance under the sinusoidal waveform of 250 Vpp.
The micro pump achieved the maximum pumping rates of 1185
ml/min and back pressure of 7.14 kPa at the corresponding frequency
of 120 and 50 Hz.
Abstract: This work consists of a numerical simulation of
convective heat transfer in a vertical plane channel filled with a heat
generating porous medium, in the absence of local thermal
equilibrium. The walls are maintained to a constant temperature and
the inlet velocity is uniform. The dynamic range is described by the
Darcy-Brinkman model and the thermal field by two energy
equations model. A dimensionless formulation is developed for
performing a parametric study based on certain dimensionless groups
such as, the Biot interstitial number, the thermal conductivity ratio
and the volumetric heat generation, q '''. The governing equations are
solved using the finite volume method, gave rise to a multitude of
results concerning in particular the thermal field in the porous
channel and the existence or not of the local thermal equilibrium.
Abstract: Currently, continuous two-phase decanter process
used for olive oil production is the more internationally widespread.
The wastewaters generated from this industry (OMW) are a real
environmental problem because of its high organic load. Among
proposed treatments for these wastewaters, advanced oxidation
technologies (Fenton, ozone, photoFenton, etc.) are the most
favourable. The direct application of these processes is somewhat
expensive. Therefore, the application of a previous stage based on a
flocculation-sedimentation operation is of high importance. In this
research five commercial flocculants (three cationic, and two anionic)
have been used to achieve the separation of phases (liquid clarifiedsludge).
For each flocculant, different concentrations (0-1000 mg/L)
have been studied. In these experiments, sludge volume formed and
the final water quality were determined. The final removal
percentages of total phenols (11.3-25.1%), COD (5.6-20.4%), total
carbon (2.3-26.5%), total organic carbon (1.50-23.8%), total nitrogen
(1.45-24.8%), and turbidity (27.9-61.4%) were determined. The
variation on electric conductivity reduction percentage (1-8%) was
also determined. Finally, the best flocculants with highest removal
percentages have been determined (QG2001 and Flocudex CS49).
Abstract: HZSM-5 zeolites modified by iron and phosphorus
were applied in catalytic cracking of butene. N2 adsorption and
NH3-TPD were employed to measure the structure and acidity of
catalysts. The results indicate that increasing phosphorus loading
decreased surface area, pore volume and strong acidity of catalysts.
The addition of phosphorus significantly decreased butene conversion
and promoted propylene selectivity. The catalytic performance of
catalyst was strongly dependent on the reaction conditions.
Appropriate reaction conditions could suppress side reactions and
enhance propylene selectivity.
Abstract: Fibre cement plates, often used in construction,
generally are made using quartz as an inert material, cement as a
binder and cellulose as a fibre. This paper, first of all, investigates the
mechanical properties and durability of fibre cement plates when
quartz is both partly and fully replaced with diatomite. Diatomite
does not only have lower density compared to quartz but also has
high pozzolanic activity. The main objective of this paper is the
investigation of the effects of supplementary cementing materials
(SCMs) on the short and long term mechanical properties and
durability characteristics of fibre cement plates prepared using
diatomite. Supplementary cementing materials such as ground
granulated blast furnace slug (GGBS) and fly ash (FA) are used in
this study. Volume proportions of 10, 20, 30 and 40% of GGBS and
FA are used as partial replacement materials to cement. Short and
long term mechanical properties such as compressive and flexural
strengths as well as sorptivity characteristics and mass were
investigated. Consistency and setting time at each replacement levels
of SCMs were also recorded. The effects of using supplementary
cementing materials on the carbonation and sulphate resistance of
fibre cement plates were then experimented. The results, first of all,
show that the use of diatomite as a full or partial replacement to
quartz resulted in a systematic decrease in total mass of the fibre
cement plates. The reduction of mass was largely due to the lower
density and finer particle size of diatomite compared to quartz. The
use of diatomite did not only reduce the mass of these plates but also
increased the compressive strength significantly as a result of its high
pozzolanic activity. The replacement levels of both GGBS and FA
resulted in a systematic decrease in short term compressive strength
with increasing replacement levels. This was essentially expected as
the total rate of hydration is much lower in GGBS and FA than that
of cement. Long term results however, indicated that the compressive
strength of fibre cement plates prepared using both GGBS and FA
increases with time and hence the compressive strength of plates
prepared using SCMs is either equivalent or more than the
compressive strength of plates prepared using cement alone.
Durability characteristics of fibre cement plates prepared using SCMs
were enhanced significantly. Measurements of sopritivty
characteristics were also indicated that the plates prepared using
SCMs has much lower water absorption capacities compared to
plates prepared cement alone. Much higher resistance to carbonation
and sulphate attach were observed with plates prepared using SCMs.
The results presented in this paper show that the use of SCMs does
not only support the production of more sustainable construction
materials but also enhances the mechanical properties and durability
characteristics of fibre cement plates.
Abstract: Experimental investigations of the DC electric field effect on thermal decomposition of biomass, formation of the axial flow of volatiles (CO, H2, CxHy), mixing of volatiles with swirling airflow at low swirl intensity (S ≈ 0.2-0.35), their ignition and on formation of combustion dynamics are carried out with the aim to understand the mechanism of electric field influence on biomass gasification, combustion of volatiles and heat energy production. The DC electric field effect on combustion dynamics was studied by varying the positive bias voltage of the central electrode from 0.6 kV to 3 kV, whereas the ion current was limited to 2 mA. The results of experimental investigations confirm the field-enhanced biomass gasification with enhanced release of volatiles and the development of endothermic processes at the primary stage of thermochemical conversion of biomass determining the field-enhanced heat energy consumption with the correlating decrease of the flame temperature and heat energy production at this stage of flame formation. Further, the field-enhanced radial expansion of the flame reaction zone correlates with a more complete combustion of volatiles increasing the combustion efficiency by 3% and decreasing the mass fraction of CO, H2 and CxHy in the products, whereas by 10% increases the average volume fraction of CO2 and the heat energy production downstream the combustor increases by 5-10%
Abstract: Boiling process is characterized by the rapid
formation of vapour bubbles at the solid–liquid interface (nucleate
boiling) with pre-existing vapour or gas pockets. Computational fluid
dynamics (CFD) is an important tool to study bubble dynamics. In
the present study, CFD simulation has been carried out to determine
the bubble detachment diameter and its terminal velocity. Volume of
fluid method is used to model the bubble and the surrounding by
solving single set of momentum equations and tracking the volume
fraction of each of the fluids throughout the domain. In the
simulation, bubble is generated by allowing water-vapour to enter a
cylinder filled with liquid water through an inlet at the bottom. After
the bubble is fully formed, the bubble detaches from the surface and
rises up during which the bubble accelerates due to the net balance
between buoyancy force and viscous drag. Finally when these forces
exactly balance each other, it attains a constant terminal velocity. The
bubble detachment diameter and the terminal velocity of the bubble
are captured by the monitor function provided in FLUENT. The
detachment diameter and the terminal velocity obtained are compared
with the established results based on the shape of the bubble. A good
agreement is obtained between the results obtained from simulation
and the equations in comparison with the established results.
Abstract: This paper presents a computational study of steady
state three dimensional very high turbulent flow and heat transfer
characteristics in a constant temperature-surfaced circular duct fitted
with 900 hemispherical inline baffles. The computations are based on
realizable k-ɛ model with standard wall function considering the
finite volume method, and the SIMPLE algorithm has been
implemented. Computational Study are carried out for Reynolds
number, Re ranging from 80000 to 120000, Prandtl Number, Pr of
0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of
the channel, hydrodynamic entry length, thermal entry length and the
test section. Ansys Fluent 15.0 software has been used to solve the
flow field. Study reveals that circular pipe having baffles has a higher
Nusselt number and friction factor compared to the smooth circular
pipe without baffles. Maximum Nusselt number and friction factor
are obtained for the PR=5 and PR=1 respectively. Nusselt number
increases while pitch ratio increases in the range of study; however,
friction factor also decreases up to PR 3 and after which it becomes
almost constant up to PR 5. Thermal enhancement factor increases
with increasing pitch ratio but with slightly decreasing Reynolds
number in the range of study and becomes almost constant at higher
Reynolds number. The computational results reveal that optimum
thermal enhancement factor of 900 inline hemispherical baffle is
about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows
that the optimum pitch ratio for which the baffles can be installed in
such very high turbulent flows should be 5. Results show that pitch
ratio and Reynolds number play an important role on both fluid flow
and heat transfer characteristics.
Abstract: In this work, the Ictalurus punctatus species estimated
available physical habitat is compared with the estimated physical
habitat for the same but modified river reach, with the aim of creating
a linear park, along a length of 5 500 m.
To determine the effect of ecological park construction, on
physical habitat of the Lerma river stretch of study, first, the available
habitat for the Ictalurus punctatus species was estimated through the
simulation of the physical habitat, by using surveying, hydraulics,
and habitat information gotten at the river reach in its actual situation.
Second, it was estimated the available habitat for the above species,
upon the simulation of the physical habitat through the proposed
modification for the ecological park creation. Third, it is presented a
comparison between both scenarios in terms of available habitat
estimated for Ictalurus punctatus species, concluding that in cases of
adult and spawning life stages, changes in the channel to create an
ecological park would produce a considerable loss of potentially
usable habitat (PUH), while in the case of the juvenile life stage PUH
remains virtually unchanged, and in the case of life stage fry the PUH
would increase due to the presence of velocities and depths of lesser
magnitude, due to the presence of minor flow rates and lower volume
of the wet channel.
It is expected that habitat modification for linear park construction
may produce the lack of Ictalurus punktatus species conservation at
the river reach of the study.
Abstract: The venture capital becomes more and more advanced
and effective source of the innovation project financing, connected
with a high-risk level. In the developed countries, it plays a key role
in transforming innovation projects into successful businesses and
creating the prosperity of the modern economy. In Russia, there are
many necessary preconditions for creation of the effective venture
investment system: the network of the public institutes for innovation
financing operates; there is a significant number of the small and
medium-sized enterprises, capable to sell production with good
market potential. However, the current system does not confirm the
necessary level of efficiency in practice that can be substantially
explained by the absence of the accurate plan of action to form the
national venture model and by the lack of experience of successful
venture deals with profitable exits in Russian economy. This paper
studies the influence of various factors on the venture industry
development by the example of the IT-sector in Russia. The choice of
the sector is based on the fact, that this segment is the main driver of
the venture capital market growth in Russia, and the necessary set of
data exists. The size of investment of the second round is used as the
dependent variable. To analyse the influence of the previous round,
such determinant as the volume of the previous (first) round
investments is used. There is also used a dummy variable in
regression to examine that the participation of an investor with high
reputation and experience in the previous round can influence the size
of the next investment round. The regression analysis of short-term
interrelations between studied variables reveals prevailing influence
of the volume of the first round investments on the venture
investments volume of the second round. The most important
determinant of the value of the second-round investment is the value
of first–round investment, so it means that the most competitive on
the Russian market are the start-up teams that can attract more money
on the start, and the target market growth is not the factor of crucial
importance. This supports the point of view that VC in Russia is
driven by endogenous factors and not by exogenous ones that are
based on global market growth.
Abstract: Electrohydraulic servo system have been used in industry in a wide number of applications. Its dynamics are highly nonlinear and also have large extent of model uncertainties and external disturbances. In this paper, a robust back-stepping control (RBSC) scheme is proposed to overcome the problem of disturbances and system uncertainties effectively and to improve the tracking performance of EHS systems. In order to implement the proposed control scheme, the system uncertainties in EHS systems are considered as total leakage coefficient and effective oil volume. In addition, in order to obtain the virtual controls for stabilizing system, the update rule for the system uncertainty term is induced by the Lyapunov control function (LCF). To verify the performance and robustness of the proposed control system, computer simulation of the proposed control system using Matlab/Simulink Software is executed. From the computer simulation, it was found that the RBSC system produces the desired tracking performance and has robustness to the disturbances and system uncertainties of EHS systems.
Abstract: Presently a significant portion of the Earth's
population does not have access to healthy food. Either because they
cannot afford it or because they do not know which one are they. The
aim of the VII th Framework Chance project (Nr. 266331) supported
by the European Union has been to develop relatively cheap food
with favourable nutritional value and it should have acceptable
quality for consumers. As one task of the project we manufactured
bread products as a basic food. We examined the enrichment of bread
products with four kinds of bran, with a special milling product of
grain industry (aleurone-rich flour) and with a soy-based sprouted
additive. The applied concentration of the six mentioned additives
has been optimized and the physical properties of the bread products
were monitored. The weight/density of the enriched breads increased
a bit, however the volume and height decreased slightly compared to
the corresponding data of the control bread. The optimized
composition of the final product is favourably affected by these
additives having highly preferred composition from nutritional point
of view.