Abstract: In the present study, the properties of Al-Al2O3
nanocomposite hollow sphere structures were investigated. For this
reason, the Al-based nanocomposite hollow spheres with different
amounts of nano-alumina reinforcement (0-10wt %) and different
ratio of thickness to diameter (t/D: 0.06-0.3) were prepared via a
powder metallurgy method. Then, the effect of mentioned parameters
was studied on physical and quasi static mechanical properties of
their related prepared structures (open/closed cell) such as density,
hardness, strength, and energy absorption. It was found that, as the
t/D ratio increases the relative density, compressive strength and
energy absorption increase. The highest values of strength and energy
absorption were obtained from the specimen with 5 wt. % of
nanoparticle reinforcement, t/D of 0.3 (t=1 mm, D=400μm) as 22.88
MPa and 13.24 MJ/m3, respectively. The moderate specific strength
of prepared composites in the present study showed the good
consistency with the properties of others low carbon steel composite
with similar structure.
Abstract: Life cycle assessment is a technique to assess the
environmental aspects and potential impacts associated with a
product, process, or service, by compiling an inventory of relevant
energy and material inputs and environmental releases; evaluating the
potential environmental impacts associated with identified inputs and
releases; and interpreting the results to help you make a more
informed decision. In this paper, the life cycle assessment of
aluminum and beech wood as two commonly used materials in Egypt
for window frames are heading, highlighting their benefits and
weaknesses. Window frames of the two materials have been assessed
on the basis of their production, energy consumption and
environmental impacts. It has been found that the climate change of
the windows made of aluminum and beech wood window, for a
reference window (1.2m×1.2m), are 81.7 mPt and -52.5 mPt impacts
respectively. Among the most important results are: fossil fuel
consumption, potential contributions to the green building effect and
quantities of solid waste tend to be minor for wood products
compared to aluminum products; incineration of wood products can
cause higher impacts of acidification and eutrophication than
aluminum, whereas thermal energy can be recovered.
Abstract: This paper presents the results obtained by numerical
simulation using the software ANSYS CFX-CFD for the air
pollutants dispersion in the atmosphere coming from the evacuation
of combustion gases resulting from the fuel combustion in an electric
thermal power plant. The model uses the Navier-Stokes equation to
simulate the dispersion of pollutants in the atmosphere. It is
considered as important factors in elaboration of simulation the
atmospheric conditions (pressure, temperature, wind speed, wind
direction), the exhaust velocity of the combustion gases, chimney
height and the obstacles (buildings). Using the air quality monitoring
stations it is measured the concentrations of main pollutants (SO2,
NOx and PM). The pollutants were monitored over a period of 3
months, after that the average concentration are calculated, which is
used by the software. The concentrations are: 8.915 μg/m3 (NOx),
9.587 μg/m3 (SO2) and 42 μg/m3 (PM). A comparison of test data
with simulation results demonstrated that CFX was able to describe
the dispersion of the pollutant as well the concentration of this
pollutants in the atmosphere.
Abstract: In this paper, analysis of an infinite beam resting on
multilayer tensionless extensible geosynthetic reinforced granular
fill-poor soil system overlying soft soil strata under moving load with
constant velocity is presented. The beam is subjected to a
concentrated load moving with constant velocity. The upper
reinforced granular bed is modeled by a rough membrane embedded
in Pasternak shear layer overlying a series of compressible nonlinear
winkler springs representing the underlying the very poor soil. The
multilayer tensionless extensible geosynthetic layer has been
assumed to deform such that at interface the geosynthetic and the soil
have some deformation. Nonlinear behaviour of granular fill and the
very poor soil has been considered in the analysis by means of
hyperbolic constitutive relationships. Governing differential
equations of the soil foundation system have been obtained and
solved with the help of appropriate boundary conditions. The solution
has been obtained by employing finite difference method by means of
Gauss-Siedal iterative scheme. Detailed parametric study has been
conducted to study the influence of various parameters on the
response of soil–foundation system under consideration by means of
deflection and bending moment in the beam and tension mobilized in
the geosynthetic layer. These parameters include magnitude of
applied load, velocity of load, damping, ultimate resistance of poor
soil and granular fill layer. Range of values of parameters has been
considered as per Indian Railway conditions. This study clearly
observed that the comparisons of multilayer tensionless extensible
geosynthetic reinforcement with poor foundation soil and magnitude
of applied load, relative compressibility of granular fill and ultimate
resistance of poor soil has significant influence on the response of
soil–foundation system.
Abstract: The purpose of this study is the discrimination of 28
postmenopausal with osteoporotic femoral fractures from an agematched
control group of 28 women using texture analysis based on
fractals. Two pre-processing approaches are applied on radiographic
images; these techniques are compared to highlight the choice of the
pre-processing method. Furthermore, the values of the fractal
dimension are compared to those of the fractal signature in terms of
the classification of the two populations. In a second analysis, the
BMD measure at proximal femur was compared to the fractal
analysis, the latter, which is a non-invasive technique, allowed a
better discrimination; the results confirm that the fractal analysis of
texture on calcaneus radiographs is able to discriminate osteoporotic
patients with femoral fracture from controls. This discrimination was
efficient compared to that obtained by BMD alone. It was also
present in comparing subgroups with overlapping values of BMD.
Abstract: Method of combined teaching laws of classical
mechanics and hydrostatics in non-inertial reference frames for
undergraduate students is proposed. Pressure distribution in a liquid
(or gas) moving with acceleration is considered. Combined effect of
hydrostatic force and force of inertia on a body immersed in a liquid
can lead to paradoxical results, in a motion of pendulum in particular.
The body motion under Stokes force influence and forces in rotating
reference frames are investigated as well. Problems and difficulties in
student perceptions are analyzed.
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 applied factor conditions from Porter’s
Diamond Model (1990) to understand the various challenges facing
the AMISA. Factor conditions highlighted in Porter’s model are
grouped into two groups namely, basic and advance factors. Two
AMISA associations representing over 10 000 employees were
interviewed. The largest Clothing, Textiles and Leather (CTL)
apparel retail group was also interviewed with a government
department implementing the industrialization policy were
interviewed. The paper points out that AMISA have basic factor conditions
necessary for competitive advantage in the apparel industries.
However advance factor creation has proven to be a challenge for
AMISA, Higher Education Institutions (HEIs) and government. Poor
infrastructural maintenance has contributed to high manufacturing
costs and poor quick response technologies. The use of Porter’s
Factor Conditions as a tool to analyze the sector’s competitive
advantage challenges and opportunities has increased knowledge
regarding factors that limit the AMISA’s competitiveness. It is
therefore argued that other studies on Porter’s Diamond model
factors like Demand conditions, Firm strategy, structure and rivalry
and Related and supporting industries can be used to analyze the
situation of the AMISA for the purposes of improving competitive
advantage.
Abstract: Propagation of arbitrary amplitude nonlinear Alfven
waves has been investigated in low but finite β electron-positron-ion
plasma including full ion dynamics. Using Sagdeev pseudopotential
method an energy integral equation has been derived. The Sagdeev
potential has been calculated for different plasma parameters and it
has been shown that inclusion of ion parallel motion along the
magnetic field changes the nature of slow shear Alfven wave solitons
from dip type to hump type. The effects of positron concentration,
plasma-β and obliqueness of the wave propagation on the solitary
wave structure have also been examined.
Abstract: Drying is a phenomenon that accompanies the
hardening of hydraulic materials. This study is concerned the
modelling of drying shrinkage of the hydraulic materials and the
prediction of the rate of spontaneous deformations of hydraulic
materials during hardening. The model developed takes consideration
of the main factors affecting drying shrinkage. There was agreement
between drying shrinkage predicted by the developed model and
experimental results. In last we show that developed model describe
the evolution of the drying shrinkage of high performances concretes
correctly.
Abstract: Background: Muscle Energy Techniques (MET) have
been widely used by manual therapists over the past years, but still
limited research validated its use and there was limited evidence to
substantiate the theories used to explain its effects. Objective: To
investigate the effect of Muscle Energy Technique (MET) on anterior
pelvic tilt in patients with lumbar spondylosis. Design: Randomized
controlled trial. Subjects: Thirty patients with anterior pelvic tilt from
both sexes were involved, aged between 35 to 50 years old and they
were divided into MET and control groups with 15 patients in each.
Methods: All patients received 3sessions/week for 4 weeks where the
study group received MET, Ultrasound and Infrared, and the control
group received U.S and I.R only. Pelvic angle was measured by
palpation meter, pain severity by the visual analogue scale and
functional disabilities by the Oswestry disability index. Results: Both
groups showed significant improvement in all measured variables.
The MET group was significantly better than the control group in
pelvic angle, pain severity, and functional disability as p-value were
(0.001, 0.0001, 0.0001) respectively. Conclusion and implication: the
study group fulfilled greater improvement in all measured variables
than the control group which implies that application of MET in
combination with U.S and I.R were more effective in improving
pelvic tilting angle, pain severity and functional disabilities than
using electrotherapy only.
Abstract: To evaluate the vigor of wheat seeds and stress of
premature aging effects on germination percentage, root length and
shoot length of five wheat cultivars that include Vynak, Karkheh,
Chamran, Star and Kavir which underwent a period of zero, two,
three, four days in terms of premature aging with 41°C temperature
and 100% relative humidity. Seed germination percentage, root
length and shoot length in these conditions were measured. This
experiment was conducted as a factorial completely randomized
design with four replications in laboratory conditions. The results
showed that each of aging treatments used in this experiment can be
used to detect differences in vigor of wheat varieties. Wheat cultivars
illustrated significant differences in germination percentage, root
length and shoot length in terms of premature aging. The wheat
cultivars; Astar and Vynak had maximum germination percentage
and Karkheh, respectively Kavir and Chamran had lowest percentage
of seed germination. Reactions of root and shoot length of wheat
cultivars was also different. The results showed that the seeds with a
stronger vigor affected less in premature aging condition and the
difference between the percentage of seed germination under normal
conditions and stress was significant and the seeds with the weaker
vigor were more sensitive to the premature aging stress and the
premature aging had more severe negative impact on seed vigor.
Abstract: This paper presents results of the survey regarding the
awareness about HIV/AIDS among HIV-infected individuals. A
questionnaire covering various aspects of HIV-infection was
conducted among 110 HIV-infected individuals who attended the
G.A. Zaharyan Moscow Tuberculosis Clinic, Department for
treatment of TB patients with HIV. The questionnaire included
questions about modes of HIV transmission and preventive measures
against HIV/AIDS, as well as questions about age, gender, education
and employment status. The survey revealed that the respondents in
the whole had a good knowledge regarding modes of HIV
transmission and preventive measures against HIV/AIDS: about
83,6% male respondents and 85,7% female respondents gave an
accurate answers regarding the HIV-infection. However, the
overwhelming majority of the study participants, that is, 88,5% men
and 98% women, was quite ignorant about the risk of acquiring HIV
through saliva and toothbrush of HIV-infected individual. Though
that risk is rather insignificant, it is still biologically possible. And
this gap in knowledge needs to be filled. As the study showed another
point of concern was the fact, that despite the knowledge of HIV
transmission risk through unprotected sex about 40% percent of HIVpositive
men and 25% of HIV-positive women did not insist on using
condoms with their sexual partners. These findings indicate that there
are still some aspects about HIV-infection which needed to be
clarified and explained through more detailed and specific
educational programs.
Abstract: Singular value decomposition based optimisation of
geometric design parameters of a 5-speed gearbox is studied. During
the optimisation, a four-degree-of freedom torsional vibration model
of the pinion gear-wheel gear system is obtained and the minimum
singular value of the transfer matrix is considered as the objective
functions. The computational cost of the associated singular value
problems is quite low for the objective function, because it is only
necessary to compute the largest and smallest singular values (μmax
and μmin) that can be achieved by using selective eigenvalue solvers;
the other singular values are not needed. The design parameters are
optimised under several constraints that include bending stress,
contact stress and constant distance between gear centres. Thus, by
optimising the geometric parameters of the gearbox such as, the
module, number of teeth and face width it is possible to obtain a
light-weight-gearbox structure. It is concluded that the all optimised
geometric design parameters also satisfy all constraints.
Abstract: This study makes an integrated investigation on how
life satisfaction is associated with the Korean game users'
psychological variables (self-esteem, game and life self- efficacy),
social variables (bonding and bridging social capital), and
demographic variables (age, gender). The data used for the empirical
analysis came from a representative sample survey conducted in South
Korea. Results show that self-esteem and game efficacy were an
important antecedent to the degree of users’ life satisfaction. Both
bonding social capital and bridging social capital enhance the level of
the users’ life satisfaction. The importance of perspectives as well as
their implications for the game users and further associated research is
explored.
Abstract: Tool, Die and Mould-making (TDM) firms have been
known to play a pivotal role in the growth and development of the
manufacturing sectors in most economies. Their output contributes
significantly to the quality, cost and delivery speed of final
manufactured parts. Unfortunately, the South African Tool, Die and
Mould-making manufacturers have not been competing on the local
or global market in a significant way. This reality has hampered the
productivity and growth of the sector thus attracting intervention. The
paper explores the shortcomings South African toolmakers have to
overcome to restore their competitive position globally. Results from
a global benchmarking survey on the tooling sector are used to
establish a roadmap of what South African toolmakers can do to
become a productive, World Class force on the global market.
Abstract: Workflow scheduling is an important part of cloud
computing and based on different criteria it decides cost, execution
time, and performances. A cloud workflow system is a platform
service facilitating automation of distributed applications based on
new cloud infrastructure. An aspect which differentiates cloud
workflow system from others is market-oriented business model, an
innovation which challenges conventional workflow scheduling
strategies. Time and Cost optimization algorithm for scheduling
Hybrid Clouds (TCHC) algorithm decides which resource should be
chartered from public providers is combined with a new De-De
algorithm considering that every instance of single and multiple
workflows work without deadlocks. To offset this, two new concepts
- De-De Dodging Algorithm and Priority Based Decisive Algorithm -
combine with conventional deadlock avoidance issues by proposing
one algorithm that maximizes active (not just allocated) resource use
and reduces Makespan.
Abstract: This paper presents the design process of a high
performance 3-phase 3.7 kW 2-pole line start permanent magnet
synchronous motor for pumping system. A method was proposed to
study the starting torque characteristics considering line start with
high inertia load. A d-q model including cage was built to study the
synchronization capability. Time-stepping finite element method
analysis was utilized to accurately predict the dynamic and transient
performance, efficiency, starting current, speed curve and etc.
Considering the load torque of pumps during starting stage, the rotor
bar was designed with minimum demagnetization of permanent
magnet caused by huge starting current.
Abstract: A novel chromium-free protective coating films based
on a zeolite coating was growing onto a FeCrAlloy metal using in –
situ hydrothermal method. The zeolite film was obtained using in-situ
crystallization process that is capable of coating large surfaces with
complex shape and in confined spaces has been developed. The
zeolite coating offers an advantage of a high mechanical stability and
thermal stability. The physicochemical properties were investigated
using X-ray diffraction (XRD), Electron Microscopy (SEM), Energy
Dispersive X–ray Analysis (EDX) and Thermogravimetric Analysis
(TGA). The transition from oxide-on-alloy wires to hydrothermally
synthesised uniformly zeolite coated surfaces was followed using
SEM and XRD. In addition, the robustness of the prepared coating
was confirmed by subjecting these to thermal cycling (ambient to
550oC).
Abstract: The purpose of this article is to make an approach to
the Security Studies, exposing their theories and concepts to
understand the role that they have had in the interpretation of the
changes and continuities of the world order and their impact on
policies in facing the problems of the 21st century. The aim is to
build a bridge between the security studies as a subfield and the
meaning that has been given to the world order. The idea of epistemic
communities serves as a methodological proposal for the different
programs of research in security studies, showing their influence in
the realities of States, intergovernmental organizations and
transnational forces, moving to implement, perpetuate and project a
vision of the world order.