Abstract: A solar receiver is designed for operation under
extremely uneven heat flux distribution, cyclic weather, and cloud
transient cycle conditions, which can include large thermal stress and
even receiver failure. In this study, the effect of different oil velocity
on convection coefficient factor and impact of wind velocity on local
Nusselt number by Finite Volume Method will be analyzed. This
study is organized to give an overview of the numerical modeling
using a MATLAB software, as an accurate, time efficient and
economical way of analyzing the heat transfer trends over stationary
receiver tube for different Reynolds number. The results reveal when
oil velocity is below 0.33m/s, the value of convection coefficient is
negligible at low temperature. The numerical graphs indicate that
when oil velocity increases up to 1.2 m/s, heat convection coefficient
increases significantly. In fact, a reduction in oil velocity causes a
reduction in heat conduction through the glass envelope. In addition,
the different local Nusselt number is reduced when the wind blows
toward the concave side of the collector and it has a significant effect
on heat losses reduction through the glass envelope.
Abstract: Experience is what makes a man perfect. Though we
tend to learn many a different things in life through practice still we
need to go an extra mile to gain experience which would be profitable
only when it is integrated with regular practice. A clear phenomenal
idea is that every teacher is a learner. The centralized idea of this paper would focus on the integrated
practices carried out among the students of Jizan University which
enhances learning through experiences. Integrated practices like
student-directed activities, balanced curriculum, phonological based
activities and use of consistent language would enlarge the vision and
mission of students to earn experience through learning. Students
who receive explicit instruction and guidance could practice the skills
and strategies through student-directed activities such as peer tutoring
and cooperative learning. The second effective practice is to use
consistent language. Consistent language provides students a model
for talking about the new concepts which also enables them to
communicate without hindrances. Phonological awareness is an
important early reading skill for all students. Students generally have
phonemic awareness in their home language can often transfer that
knowledge to a second language. And also a balanced curriculum
requires instruction in all the elements of reading. Reading is the
most effective skill when both basic and higher-order skills are
included on a daily basis. Computer based reading and listening skills
will empower students to understand language in a better way.
English language learners can benefit from sound reading instruction
even before they are fully proficient in English as long as the
instruction is comprehensible. Thus, if students have to be well
equipped in learning they should foreground themselves in various
integrated practices through multifarious experience for which
teachers are moderators and trainers. This type of learning prepares
the students for a constantly changing society which helps them to
meet the competitive world around them for better employability
fulfilling the vision and mission of the institution.
Abstract: Green concrete are generally composed of recycling
materials as hundred or partial percent substitutes for aggregate,
cement, and admixture in concrete. To reduce greenhouse gas
emissions, efforts are needed to develop environmentally friendly
construction materials. Using of fly ash based geopolymer as an
alternative binder can help reduce CO2 emission of concrete. The
binder of geopolymer concrete is different from the ordinary Portland
cement concrete. Geopolymer Concrete specimens were prepared
with different concentration of NaOH solution M10, M14, and, M16
and cured at 60ºC in duration of 24 hours and 8 hours, in addition to
the curing in direct sunlight. Thus, it is necessary to study the effects
of the geopolymer binder on the behavior of concrete. Concrete is
made by using geopolymer technology is environmental friendly and
could be considered as part of the sustainable development. In this
study, the Local Alkaline Activator in Egypt and crashed stone as
coarse aggregate in fly ash based-geopolymer concrete was
investigated. This paper illustrates the development of mechanical
properties. Since the gained compressive strength for geopolymer
concrete at 28 days was in the range of 22.5MPa – 43.9MPa.
Abstract: A method of effective planning and control of
industrial facility energy consumption is offered. The method allows
optimally arranging the management and full control of complex
production facilities in accordance with the criteria of minimal
technical and economic losses at the forecasting control. The method
is based on the optimal construction of the power efficiency
characteristics with the prescribed accuracy. The problem of optimal
designing of the forecasting model is solved on the basis of three
criteria: maximizing the weighted sum of the points of forecasting
with the prescribed accuracy; the solving of the problem by the
standard principles at the incomplete statistic data on the basis of
minimization of the regularized function; minimizing the technical
and economic losses due to the forecasting errors.
Abstract: Electrical Muscle Stimulation (EMS) has been
introduced and globally gained increasing attention on its usefulness.
Continuous application of EMS may lead to the increment of muscle
mass and indirectly will increase the strength. This study can be used
as an alternative to help people especially those living a sedentary
lifestyle to improve their muscle activity without having to go
through a heavy workout session. Therefore, this study intended to
investigate the effectiveness of EMS training program in 5 weeks
interventions towards male body composition. It was a quasiexperimental
design, held at the Impulse Studio Bangsar, which
examined the effects of EMS training towards skeletal muscle mass
among the subjects. Fifteen subjects (n = 15) were selected to assist
in this study. The demographic data showed that, the average age of
the subjects was 43.07 years old ± 9.90, height (173.4 cm ± 9.09) and
weight was (85.79 kg ± 18.07). Results showed that there was a
significant difference on the skeletal muscle mass (p = 0.01 < 0.05),
upper body (p = 0.01 < 0.05) and lower body (p = 0.00 < 0.05).
Therefore, the null hypothesis has been rejected in this study. As a
conclusion, the application of EMS towards body composition can
increase the muscle size and strength. This method has been proven
to be able to improve athlete strength and thus, may be implemented
in the sports science area of knowledge.
Abstract: Local steel slag is produced as a by-product during the
oxidation of steel pellets in an electric arc furnace. Using local steel
slag waste as a hundred substitutes of crashed stone in construction
materials would resolve the environmental problems caused by the
large-scale depletion of the natural sources of crashed stone. This
paper reports the experimental study to investigate the influence of a
hundred replacement of crashed stone as a coarse aggregate with
local steel slag, on the fresh and hardened geopolymer concrete
properties. The investigation includes traditional testing of hardening
concrete, for selected mixes of cement and geopolymer concrete. It
was found that local steel slag as a coarse aggregate enhanced the
slump test of the fresh state of cement and geopolymer concretes.
Nevertheless, the unit weight of concretes was affected. Meanwhile,
the good performance was observed when fly ash used as geopolymer
concrete based.
Abstract: It is quite essential to investigate the causes of
pavement deterioration in order to select the proper maintenance
technique. The objective of this study was to identify factors cause
deterioration of recently constructed roads in Khartoum state. A
comprehensive literature concerning the factors of road deterioration,
common road defects and their causes were reviewed. Three major
road projects with different deterioration reasons were selected for
this study. The investigation involved field survey and laboratory
testing on those projects to examine the existing pavement
conditions. The results revealed that the roads investigated
experienced severe failures in the forms of cracks, potholes, and
rutting in the wheel path. The causes of those failures were found
mainly linked to poor drainage, traffic overloading, expansive
subgrade soils, and the use of low quality materials in construction.
Based on the results, recommendations were provided to help
highway engineers in selecting the most effective repair techniques
for specific kinds of distresses.
Abstract: Heat treatable aluminum alloys such as 7075 and
7055, because of high strength and low density, are used widely in
aircraft industry. For best mechanical properties, T6 heat treatment
has recommended for this regards, but this temper treatment is
sensitive to corrosion induced and Stress Corrosion Cracking (SCC)
damage. For improving this property, the over-aging treatment (T7)
applies to this alloy, but it decreases the mechanical properties up to
30 percent. Hence, to increase the mechanical properties, without any
remarkable decrease in SCC resistant, Retrogression and Re-Aging
(RRA) heat treatment is used. This treatment performs in a relatively
short time. In this paper, the RRA heat treatment was applied to 7055
aluminum alloy and then effect of RRA time on the mechanical
properties of 7055 has been investigated. The results show that the
40-minute time is suitable time for retrogression of 7055 aluminum
alloy and ultimate strength increases up to 625MPa.
Abstract: Background: Maintaining the correct body balance is
essential in the prevention of falls in the elderly, which is especially
important for women because of postmenopausal osteoporosis and
the serious consequences of falls. One of the exercise methods which
is very popular among adults, and which may affect body balance in
the positive way is the Pilates method. The aim of the study was to
evaluate the effect of regular Pilates exercises on the ability to
maintain body balance in static conditions in adult healthy women.
Material and methods: The study group consisted of 20 healthy
women attending Pilates twice a week for at least 1 year. The control
group consisted of 20 healthy women physically inactive. Women in
the age range from 35 to 50 years old without pain in musculoskeletal
system or other pain were only qualified to the groups. Body balance
was assessed using MatScan VersaTek platform with Sway Analysis
Module based on Matscan Clinical 6.7 software (Tekscan Inc.,
U.S.A). The balance was evaluated under the following conditions:
standing on both feet with eyes open, standing on both feet with eyes
closed, one-leg standing (separately on the right and left foot) with
eyes open. Each test lasted 30 seconds. The following parameters
were calculated: estimated size of the ellipse of 95% confidence, the
distance covered by the Center of Gravity (COG), the size of the
maximum shift in the sagittal and frontal planes and load distribution
between the left and right foot, as well as between rear- and forefoot.
Results: It was found that there is significant difference between the
groups in favor of the study group in the size of the confidence
ellipse and maximum shifts of COG in the sagittal plane during
standing on both feet, both with the eyes open and closed (p
Abstract: Introduction: Whole-Body Vibration (WBV) uses
high frequency mechanical stimuli generated by a vibration plate and
transmitted through bone, muscle and connective tissues to the whole
body. Research has shown that long-term vibration-plate training
improves neuromuscular facilitation, especially in afferent neural
pathways, responsible for the conduction of vibration and
proprioceptive stimuli, muscle function, balance and proprioception.
Some researchers suggest that the vibration stimulus briefly inhibits
the conduction of afferent signals from proprioceptors and can
interfere with the maintenance of body balance. The aim of this study
was to evaluate the influence of a single set of exercises associated
with whole-body vibration on the joint position sense and body
balance. Material and methods: The study enrolled 55 people aged
19-24 years. These individuals were randomly divided into a test
group (30 persons) and a control group (25 persons). Both groups
performed the same set of exercises on a vibration plate. The
following vibration parameters: frequency of 20Hz and amplitude of
3mm, were used in the test group. The control group performed
exercises on the vibration plate while it was off. All participants were
instructed to perform six dynamic exercises lasting 30 seconds each
with a 60-second period of rest between them. The exercises involved
large muscle groups of the trunk, pelvis and lower limbs.
Measurements were carried out before and immediately after
exercise. Joint position sense (JPS) was measured in the knee joint
for the starting position at 45° in an open kinematic chain. JPS error
was measured using a digital inclinometer. Balance was assessed in a
standing position with both feet on the ground with the eyes open and
closed (each test lasting 30 sec). Balance was assessed using Matscan
with FootMat 7.0 SAM software. The surface of the ellipse of
confidence and front-back as well as right-left swing were measured
to assess balance. Statistical analysis was performed using Statistica
10.0 PL software. Results: There were no significant differences
between the groups, both before and after the exercise (p> 0.05). JPS
did not change in both the test (10.7° vs. 8.4°) and control groups
(9.0° vs. 8.4°). No significant differences were shown in any of the
test parameters during balance tests with the eyes open or closed in
both the test and control groups (p> 0.05). Conclusions: 1.
Deterioration in proprioception or balance was not observed
immediately after the vibration stimulus. This suggests that vibrationinduced
blockage of proprioceptive stimuli conduction can have only
a short-lasting effect that occurs only as long as a vibration stimulus
is present. 2. Short-term use of vibration in treatment does not impair
proprioception and seems to be safe for patients with proprioceptive
impairment. 3. These results need to be supplemented with an
assessment of proprioception during the application of vibration
stimuli. Additionally, the impact of vibration parameters used in the
exercises should be evaluated.
Abstract: Foundation differential settlement and supported
structure tilting are an occasionally occurred engineering problem.
This may be caused by overloading, changes in ground soil properties
or unsupported nearby excavations. Engineering thinking points
directly toward the logic solution for such problem by uplifting the
settled side. This can be achieved with deep foundation elements
such as micro-piles and macro-piles™, jacked piers, and helical piers,
jet grouted mortar columns, compaction grout columns, cement
grouting or with chemical grouting, or traditional pit underpinning
with concrete and mortar. Although, some of these techniques offer
economic, fast and low noise solutions, many of them are quite the
contrary. For tilted structures, with the limited inclination, it may be much
easier to cause a balancing settlement on the less-settlement side
which shall be done carefully in a proper rate. This principal has been
applied in Leaning Tower of Pisa stabilization with soil extraction
from the ground surface. In this research, the authors attempt to
introduce a new solution with a different point of view. So, the
micro-tunneling technique is presented in here as an intended ground
deformation cause. In general, micro-tunneling is expected to induce
limited ground deformations. Thus, the researchers propose to apply
the technique to form small size ground unsupported holes to produce
the target deformations. This shall be done in four phases: 1.
Application of one or more micro-tunnels, regarding the existing
differential settlement value, under the raised side of the tilted
structure. 2. For each individual tunnel, the lining shall be pulled out
from both sides (from jacking and receiving shafts) in the slow rate.
3. If required, according to calculations and site records, an additional
surface load can be applied on the raised foundation side. 4. Finally, a
strengthening soil grouting shall be applied for stabilization after
adjustment. A finite element based numerical model is presented to simulate
the proposed construction phases for different tunneling positions and
tunnels group. For each case, the surface settlements are calculated
and induced plasticity points are checked. These results show the
impact of the suggested procedure on the tilted structure and its
feasibility. Comparing results also show the importance of the
position selection and tunnels group gradual effect. Thus, a new
engineering solution is presented to one of the structural and
geotechnical engineering challenges.
Abstract: The laser-ultrasonic method is realized for
quantifying the influence of porosity on the local Young’s
modulus of isotropic composite materials. The method is based on
a laser thermooptical method of ultrasound generation combined
with measurement of the phase velocity of longitudinal and shear
acoustic waves in samples. The main advantage of this method
compared with traditional ultrasonic research methods is the
efficient generation of short and powerful probing acoustic pulses
required for reliable testing of ultrasound absorbing and
scattering heterogeneous materials. Using as an example samples
of a metal matrix composite with reinforcing microparticles of
silicon carbide in various concentrations, it is shown that to
provide an effective increase in Young’s modulus with increasing
concentration of microparticles, the porosity of the final sample
should not exceed 2%.
Abstract: This study presents experimental and optimization of
nanoparticle mass concentration and heat input based on the total
thermal resistance (Rth) of loop heat pipe (LHP), employed for PCCPU
cooling. In this study, silica nanoparticles (SiO2) in water with
particle mass concentration ranged from 0% (pure water) to 1% is
considered as the working fluid within the LHP. The experimental
design and optimization is accomplished by the design of
experimental tool, Response Surface Methodology (RSM). The
results show that the nanoparticle mass concentration and the heat
input have significant effect on the Rth of LHP. For a given heat
input, the Rth is found to decrease with the increase of the
nanoparticle mass concentration up to 0.5% and increased thereafter.
It is also found that the Rth is decreased when the heat input is
increased from 20W to 60W. The results are optimized with the
objective of minimizing the Rth, using Design-Expert software, and
the optimized nanoparticle mass concentration and heat input are
0.48% and 59.97W, respectively, the minimum thermal resistance
being 2.66 (ºC/W).
Abstract: Non-linear dynamic time history analysis is
considered as the most advanced and comprehensive analytical
method for evaluating the seismic response and performance of
multi-degree-of-freedom building structures under the influence of
earthquake ground motions. However, effective and accurate
application of the method requires the implementation of advanced
hysteretic constitutive models of the various structural components
including masonry infill panels. Sophisticated computational research
tools that incorporate realistic hysteresis models for non-linear
dynamic time-history analysis are not popular among the professional
engineers as they are not only difficult to access but also complex and
time-consuming to use. In addition, commercial computer programs
for structural analysis and design that are acceptable to practicing
engineers do not generally integrate advanced hysteretic models
which can accurately simulate the hysteresis behavior of structural
elements with a realistic representation of strength degradation,
stiffness deterioration, energy dissipation and ‘pinching’ under cyclic
load reversals in the inelastic range of behavior. In this scenario,
push-over or non-linear static analysis methods have gained
significant popularity, as they can be employed to assess the seismic
performance of building structures while avoiding the complexities
and difficulties associated with non-linear dynamic time-history
analysis. “Push-over” or non-linear static analysis offers a practical
and efficient alternative to non-linear dynamic time-history analysis
for rationally evaluating the seismic demands. The present paper is
based on the analytical investigation of the effect of distribution of
masonry infill panels over the elevation of planar masonry infilled
reinforced concrete [R/C] frames on the seismic demands using the
capacity spectrum procedures implementing nonlinear static analysis
[pushover analysis] in conjunction with the response spectrum
concept. An important objective of the present study is to numerically
evaluate the adequacy of the capacity spectrum method using
pushover analysis for performance based design of masonry infilled
R/C frames for near-field earthquake ground motions.
Abstract: This paper addresses the problem of offline path
planning for Unmanned Aerial Vehicles (UAVs) in complex threedimensional
environment with obstacles, which is modelled by 3D
Cartesian grid system. Path planning for UAVs require the
computational intelligence methods to move aerial vehicles along the
flight path effectively to target while avoiding obstacles. In this paper
Modified Particle Swarm Optimization (MPSO) algorithm is applied
to generate the optimal collision free 3D flight path for UAV. The
simulations results clearly demonstrate effectiveness of the proposed
algorithm in guiding UAV to the final destination by providing
optimal feasible path quickly and effectively.
Abstract: The paper is focused to the evaluation railway tracks
in the Slovakia by using Multi-Criteria method. Evaluation of railway
tracks has important impacts for the assessment of investment in
technical equipment. Evaluation of railway tracks also has an
important impact for the allocation of marshalling yards. Marshalling
yards are in transport model as centers for the operation assigned
catchment area. This model is one of the effective ways to meet the
development strategy of the European Community's railways. By
applying this model in practice, a transport company can guarantee a
higher quality of service and then expect an increase in performance.
The model is also applicable to other rail networks. This model
supplements a theoretical problem of train formation problem of new
ways of looking at evaluation of factors affecting the organization of
wagon flows.
Abstract: The article includes the results and conclusions from
empirical researches that had been done. The research focuses on the
impact of investments made in small and medium-sized enterprises
financed from EU funds on the competitiveness of these companies.
The researches includes financial results in sales revenue and net
income, expenses, and many other new products/services on offer,
higher quality products and services, more modern methods of
production, innovation in management processes, increase in the
number of customers, increase in market share, increase in
profitability of production and provision of services. The main
conclusions are that, companies with direct investments under this
measure shall apply the modern methods of production. The
consequence of this is to increase the quality of our products and
services. Furthermore, both small and medium-sized enterprises have
introduced new products and services. Investments were carried out,
thus enabling better work organization in enterprises. Entrepreneurs
would guarantee higher quality of service, which would result in
better relationships with their customers, what is more, noting the rise
in number of clients. More than half of the companies indicated that
the investments contributed to the increase in market share. Same
thing as for market reach and brand recognition of particular
company. An interesting finding is that, investments in small
enterprises were more effective than medium-sized enterprises.
Abstract: The wider growing Finite Element Method (FEM)
application is caused by its benefits of cost saving and environment
friendly. Also, by using FEM a deep understanding of certain
phenomenon can be achieved. This paper observed the role of
material properties and volumetric change when Solid State Phase
Transformation (SSPT) takes place in residual stress formation due to
a welding process of ferritic steels through coupled Thermo-
Metallurgy-Mechanical (TMM) analysis. The correctness of FEM residual stress prediction was validated by
experiment. From parametric study of the FEM model, it can be
concluded that the material properties change tend to over-predicts
residual stress in the weld center whilst volumetric change tend to
underestimates it. The best final result is the compromise of both by
incorporates them in the model which has a better result compared to
a model without SSPT.
Abstract: Many herbal medicinal products are considered
potential anti-hypercholesterolemic agents with encouraging safety
profiles, however only a limited amount of clinical research exists to
support their efficacy. The present study was designed to compare the
antihypercholesterolemic and antioxidant activities of the crude
ethanolic extracts of Citrus reticulata fruit peel, Zingiber officinale
rhizome and Sesamum indicum seeds. Forty-five rats were used throughout the experiment which are
extended for four weeks. These were divided into nine groups, five
rats per each group as follows; group 1 was the normal control group
(rats only fed standard normal rat diet), group 2 was the
hypercholesterolemic control group (rats fed only
hypercholesterolemic diet which contained 1% cholesterol plus 10%
saturated animal fat added to the normal rat diet), groups 3 and 4
were fed hypercholesterolemic diet in addition to Citrus reticulata
ethanolic extract at doses of (250mg/kg (group 3) and 500mg/kg
(group 4)) administered daily via oral route, groups 5 and 6 were
given hypercholesterolemic diet in addition to Zingiber officinale
ethanolic extract at doses of (250mg/kg (group 5) and 500mg/kg
(group 6)) daily through oral route, groups 7 and 8 fed on
hypercholesterolemic diet in addition to Sesamum indicum ethanolic
extract at doses of (250mg/kg (group 7) and 500mg/kg (group 8))
daily orally; and group 9 rats were given hypercholesterolemic diet in
addition to atorvastatin (0.18mg/kg) daily via oral route as a standard
reference antihypercholesterolemic drug. Blood samples from all
groups were drawn from the retro-orbital venous plexus four weeks
following treatment after overnight fasting and the lipid profile (total
cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), low
density lipoprotein-cholesterol (LDL-C) and triglyceride levels) were
measured and the risk ratio (TC/HDL-C) was assessed. The
antioxidant activity of the three plants extracts was determined using
DPPH free-radical antioxidant assay. Results of in vivo and in vitro
antihypercholesterolemic and antioxidant assay respectively, revealed
that the three extracts possess comparable antioxidant and
antihypercholesterolemic activities.
Abstract: The contemporary battlefield creates a demand for
more costly and highly advanced munitions. Training personnel
responsible for operations as well as immediate execution of combat
tasks which engage real asset is unrealistic and economically not
feasible. Owing to a wide array of exploited simulators and various
types of imitators, it is possible to reduce the costs. One of the
effective elements of training, which can be applied in the training of
all service branches, is imitator of aerial targets. This research serves
as an introduction to the commencement of design analysis over a
real aerial target imitator. Within the project, the basic aerodynamic
calculations were made, which enabled to determine its geometry,
design layout, performance as well as mass balance of individual
components. The conducted calculations of the parameters of flight
characteristics come closer to the real performance of such
Unmanned Aerial Vehicles.