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: A solution methodology without using integral
transformation is proposed to develop analytical solutions for
transient heat conduction in nonuniform hollow cylinders with
time-dependent boundary condition at the outer surface. It is shown
that if the thermal conductivity and the specific heat of the medium
are in arbitrary polynomial function forms, the closed solutions of the
system can be developed. The influence of physical properties on the
temperature distribution of the system is studied. A numerical
example is given to illustrate the efficiency and the accuracy of the
solution methodology.
Abstract: The use of titanium fluoride and iron fluoride
(TiF3/FeF3) catalysts in combination with polutetrafluoroethylene
(PTFE) in plain zinc- dialkyldithiophosphate (ZDDP) oil is important
for the study of engine tribocomponents and is increasingly a strategy
to improve the formation of tribofilm and provide low friction and
excellent wear protection in reduced phosphorus plain ZDDP oil. The
influence of surface roughness and the concentration of
TiF3/FeF3/PTFE were investigated using bearing steel samples
dipped in lubricant solution at 100°C for two different heating time
durations. This paper addresses the effects of water drop contact
angle using different surface; finishes after treating them with
different lubricant combination. The calculated water drop contact
angles were analyzed using Design of Experiment software (DOE)
and it was determined that a 0.05 μm Ra surface roughness would
provide an excellent TiF3/FeF3/PTFE coating for antiwear resistance
as reflected in the Scanning electron microscopy (SEM) images and
the tribological testing under extreme pressure conditions. Both
friction and wear performance depend greatly on the PTFE/and
catalysts in plain ZDDP oil with 0.05 % phosphorous and on the
surface finish of bearing steel. The friction and wear reducing effects,
which was observed in the tribological tests, indicated a better micro
lubrication effect of the 0.05 μm Ra surface roughness treated at
100°C for 24 hours when compared to the 0.1 μm Ra surface
roughness with the same treatment.
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: 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: 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: Particle size distribution, the most important
characteristics of aerosols, is obtained through electrical
characterization techniques. The dynamics of charged nanoparticles
under the influence of electric field in Electrical Mobility
Spectrometer (EMS) reveals the size distribution of these particles.
The accuracy of this measurement is influenced by flow conditions,
geometry, electric field and particle charging process, therefore by
the transfer function (transfer matrix) of the instrument. In this work,
a wire-cylinder corona charger was designed and the combined fielddiffusion
charging process of injected poly-disperse aerosol particles
was numerically simulated as a prerequisite for the study of a
multichannel EMS. The result, a cloud of particles with no uniform
charge distribution, was introduced to the EMS. The flow pattern and
electric field in the EMS were simulated using Computational Fluid
Dynamics (CFD) to obtain particle trajectories in the device and
therefore to calculate the reported signal by each electrometer.
According to the output signals (resulted from bombardment of
particles and transferring their charges as currents), we proposed a
modification to the size of detecting rings (which are connected to
electrometers) in order to evaluate particle size distributions more
accurately. Based on the capability of the system to transfer
information contents about size distribution of the injected particles,
we proposed a benchmark for the assessment of optimality of the
design. This method applies the concept of Von Neumann entropy
and borrows the definition of entropy from information theory
(Shannon entropy) to measure optimality. Entropy, according to the
Shannon entropy, is the ''average amount of information contained in
an event, sample or character extracted from a data stream''.
Evaluating the responses (signals) which were obtained via various
configurations of detecting rings, the best configuration which gave
the best predictions about the size distributions of injected particles,
was the modified configuration. It was also the one that had the
maximum amount of entropy. A reasonable consistency was also
observed between the accuracy of the predictions and the entropy
content of each configuration. In this method, entropy is extracted
from the transfer matrix of the instrument for each configuration.
Ultimately, various clouds of particles were introduced to the
simulations and predicted size distributions were compared to the
exact size distributions.
Abstract: Spacer grid assembly supporting the nuclear fuel rods
is an important concern in the design of structural components of a
Pressurized Water Reactor (PWR). The spacer grid is composed by
springs and dimples which are formed from a strip sheet by means of
blanking and stamping processes. In this paper, the blanking process
and tooling parameters are evaluated by means of a 2D plane-strain
finite element model in order to evaluate the punch load and quality
of the sheared edges of Inconel 718 strips used for nuclear spacer
grids. A 3D finite element model is also proposed to predict the
tooling loads resulting from the stamping process of a preformed
Inconel 718 strip and to analyse the residual stress effects upon the
spring and dimple design geometries of a nuclear spacer grid.
Abstract: This study identifies factors underlying the digital
divide that is faced by the disabled. The results of its analysis showed
that the digital divide in PC use is affected by age, number of years of
education, employment status, and household income of more than
KRW 3 million. The digital divide in smart device use is affected by
sex, age, number of years of education, time when disability struck,
and household income of more than KRW 3 million. Based on these
results, this study proposes methods for bridging the digital divide
faced by the disabled.
Abstract: This paper presents thermal annealing de-wetting
technique for the preparation of porous metal membrane for Thin
Film Encapsulation (TFE) application. Thermal annealing de-wetting
experimental results reveal that pore size formation in porous metal
membrane depend upon i.e. 1. The substrate at which metal is
deposited, 2. Melting point of metal used for porous metal cap layer
membrane formation, 3. Thickness of metal used for cap layer, 4.
Temperature used for formation of porous metal membrane. In order
to demonstrate this technique, Silver (Ag) was used as a metal for
preparation of porous metal membrane on amorphous silicon (a-Si)
and silicon oxide. The annealing of the silver thin film of various
thicknesses was performed at different temperature. Pores in porous
silver film were analyzed using Scanning Electron Microscope
(SEM). In order to check the usefulness of porous metal film for TFE
application, the porous silver film prepared on amorphous silicon (a-
Si) and silicon oxide was released using XeF2 and VHF, respectively.
Finally, guide line and structures are suggested to use this porous
membrane for robust TFE application.
Abstract: The aim of the present study is to investigate
consumers' determinants of intention toward the adoption of Smart
Grid solutions and technologies. Ajzen's Theory of Planned
Behaviour (TPB) model is applied and tested to explain the formation
of such adoption intention. An exogenous variable, taking into
account the resistance to change of individuals, was added to the
basic model. The elicitation study allowed obtaining salient modal
beliefs, which were used, with the support of literature, to design the
questionnaire. After the screening phase, data collected from the
main survey were analysed for evaluating measurement model's
reliability and validity. Consistent with the theory, the results of
structural equation analysis revealed that attitude, subjective norm,
and perceived behavioural control positively, which affected the
adoption intention. Specifically, the variable with the highest estimate
loading factor was found to be the perceived behavioural control,
and, the most important belief related to each construct was
determined (e.g., energy saving was observed to be the most
significant belief linked with attitude). Further investigation indicated
that the added exogenous variable has a negative influence on
intention; this finding confirmed partially the hypothesis, since this
influence was indirect: such relationship was mediated by attitude.
Implications and suggestions for future research are discussed.
Abstract: Chalcopyrite (CuFeS2) is the most common primary
mineral used for the commercial production of copper. The low
dissolution efficiency of chalcopyrite in sulfate media has prevented
an efficient industrial leaching of this mineral in sulfate media. Ferric
ions, bacteria, oxygen and other oxidants have been used as oxidizing
agents in the leaching of chalcopyrite in sulfate and chloride media
under atmospheric or pressure leaching conditions. Two leaching
methods were studied to evaluate chalcopyrite (CuFeS2) dissolution
in acid media. First, the conventional oxidative acid leaching method
was carried out using sulfuric acid (H2SO4) and potassium
dichromate (K2Cr2O7) as oxidant at atmospheric pressure. Second,
microwave-assisted acid leaching was performed using the
microwave accelerated reaction system (MARS) for same reaction
media. Parameters affecting the copper extraction such as leaching
time, leaching temperature, concentration of H2SO4 and
concentration of K2Cr2O7 were investigated. The results of
conventional acid leaching experiments were compared to the
microwave leaching method. It was found that the copper extraction
obtained under high temperature and high concentrations of oxidant
with microwave leaching is higher than those obtained
conventionally. 81% copper extraction was obtained by the
conventional oxidative acid leaching method in 180 min, with the
concentration of 0.3 mol/L K2Cr2O7 in 0.5M H2SO4 at 50 ºC, while
93.5% copper extraction was obtained in 60 min with microwave
leaching method under same conditions.
Abstract: The purpose of this project is to propose a quick and
environmentally friendly alternative to measure the quality of oils
used in food industry. There is evidence that repeated and
indiscriminate use of oils in food processing cause physicochemical
changes with formation of potentially toxic compounds that can
affect the health of consumers and cause organoleptic changes. In
order to assess the quality of oils, non-destructive optical techniques
such as Interferometry offer a rapid alternative to the use of reagents,
using only the interaction of light on the oil. Through this project, we
used interferograms of samples of oil placed under different heating
conditions to establish the changes in their quality. These
interferograms were obtained by means of a Mach-Zehnder
Interferometer using a beam of light from a HeNe laser of 10mW at
632.8nm. Each interferogram was captured, analyzed and measured
full width at half-maximum (FWHM) using the software from
Amcap and ImageJ. The total of FWHMs was organized in three
groups. It was observed that the average obtained from each of the
FWHMs of group A shows a behavior that is almost linear, therefore
it is probable that the exposure time is not relevant when the oil is
kept under constant temperature. Group B exhibits a slight
exponential model when temperature raises between 373 K and 393
K. Results of the t-Student show a probability of 95% (0.05) of the
existence of variation in the molecular composition of both samples.
Furthermore, we found a correlation between the Iodine Indexes
(Physicochemical Analysis) and the Interferograms (Optical
Analysis) of group C. Based on these results, this project highlights
the importance of the quality of the oils used in food industry and
shows how Interferometry can be a useful tool for this purpose.
Abstract: The purpose of this study is to determine the
relationship of anxiety level between male and female undergraduates
at a private university in Malaysia. Convenient sampling method used
in this study in which the students were selected based on the
grouping assigned by the faculty. There were 214 undergraduates
who registered the probability courses had participated in this study.
Mathematics Anxiety Rating Scale (MARS) was the instrument used
in study which used to determine students’ anxiety level towards
probability. Reliability and validity of instrument was done before the
major study was conducted. In the major study, students were given
briefing about the study conducted. Participation of this study was
voluntary. Students were given consent form to determine whether
they agree to participate in the study. Duration of two weeks was
given for students to complete the given online questionnaire. The
data collected will be analyzed using Statistical Package for the
Social Sciences (SPSS) to determine the level of anxiety. There were
three anxiety level, i.e., low, average and high. Students’ anxiety
level was determined based on their scores obtained compared with
the mean and standard deviation. If the scores obtained were below
mean and standard deviation, the anxiety level was low. If the scores
were at below and above the mean and between one standard
deviation, the anxiety level was average. If the scores were above the
mean and greater than one standard deviation, the anxiety level was
high. Results showed that both of genders were having average
anxiety level. Among low, average and high anxiety level, frequency
of males were found to be higher as compared to females. Hence, the
mean values obtained for males (M = 3.62) was higher than females
(M = 3.42). In order to be significant of anxiety level among the
gender, the p-value should be less than .05. The p-value obtained in
this study was .117. However, this value was greater than .05. Thus,
there was no significant difference of anxiety level among the gender.
In other words, there was no relationship of anxiety level with the
gender.
Abstract: The design of Reverse logistics Network has attracted
growing attention with the stringent pressures from both
environmental awareness and business sustainability. Reverse
logistical activities include return, remanufacture, disassemble and
dispose of products can be quite complex to manage. In addition,
demand can be difficult to predict, and decision making is one of the
challenges task in such network. This complexity has amplified the
need to develop an integrated architecture for product return as an
enterprise system. The main purpose of this paper is to design Multi
Agent System (MAS) architecture using the Prometheus
methodology to efficiently manage reverse logistics processes. The
proposed MAS architecture includes five types of agents: Gate
keeping Agent, Collection Agent, Sorting Agent, Processing Agent
and Disposal Agent which act respectively during the five steps of
reverse logistics Network.