Abstract: Internal circulation two-platen clamping system for
injection molding machine (IMM) has many potential advantages on
energy-saving. In order to estimate its properties, experiments were
carried out in this paper. Displacement and pressure of the components
were measured. In comparison, the model of hydraulic clamping
system was established by using AMESim. The related parameters as
well as the energy consumption could be calculated. According to the
analysis, the hydraulic system was optimized in order to reduce the
energy consumption.
Abstract: The fundamental issue in understanding the origin and
growth mechanism of nanomaterials, from a fundamental unit is a big
challenging problem to the scientists. Recently, an immense attention
is generated to the researchers for prediction of exceptionally stable
atomic cluster units as the building units for future smart materials.
The present study is a systematic investigation on the stability and
electronic properties of a series of bimetallic (semiconductor-alkaline
earth) clusters, viz., BxMg3 (x=1-5) is performed, in search for
exceptional and/ or unusual stable motifs. A very popular hybrid
exchange-correlation functional, B3LYP along with a higher basis
set, viz., 6-31+G[d,p] is employed for this purpose under the density
functional formalism. The magic stability among the concerned
clusters is explained using the jellium model. It is evident from the
present study that the magic stability of B4Mg3
cluster arises due to
the jellium shell closure.
Abstract: Recently, many users have begun to frequently share
their opinions on diverse issues using various social media. Therefore,
numerous governments have attempted to establish or improve
national policies according to the public opinions captured from
various social media. In this paper, we indicate several limitations of
the traditional approaches to analyze public opinion on science and
technology and provide an alternative methodology to overcome these
limitations. First, we distinguish between the science and technology
analysis phase and the social issue analysis phase to reflect the fact that
public opinion can be formed only when a certain science and
technology is applied to a specific social issue. Next, we successively
apply a start list and a stop list to acquire clarified and interesting
results. Finally, to identify the most appropriate documents that fit
with a given subject, we develop a new logical filter concept that
consists of not only mere keywords but also a logical relationship
among the keywords. This study then analyzes the possibilities for the
practical use of the proposed methodology thorough its application to
discover core issues and public opinions from 1,700,886 documents
comprising SNS, blogs, news, and discussions.
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: Excessive fretting wear at the taper-trunnion junction
(trunnionosis) apparently contributes to the high failure rates of hip
implants. Implant wear and corrosion lead to the release of metal
particulate debris and subsequent release of metal ions at the tapertrunnion
surface. This results in a type of metal poisoning referred to
as metallosis. The consequences of metal poisoning include;
osteolysis (bone loss), osteoarthritis (pain), aseptic loosening of the
prosthesis and revision surgery. Follow up after revision surgery,
metal debris particles are commonly found in numerous locations. Background: A stable connection between the femoral ball head
(taper) and stem (trunnion) is necessary to prevent relative motions
and corrosion at the taper junction. Hence, the importance of
component assembly cannot be over-emphasized. Therefore, the aim
of this study is to determine the influence of head-stem junction
assembly by press fitting and the subsequent
disengagement/disassembly on the connection strength between the
taper ball head and stem. Methods: CoCr femoral heads were assembled with High stainless
hydrogen steel stem (trunnion) by Push-in i.e. press fit; and
disengaged by pull-out test. The strength and stability of the two
connections were evaluated by measuring the head pull-out forces
according to ISO 7206-10 standards. Findings: The head-stem junction strength linearly increases with
assembly forces.
Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) are
formed mainly because of incomplete combustion of organic
materials during industrial, domestic activities or natural occurrence.
Their toxicity and contamination of terrestrial and aquatic ecosystem
have been established. However, with limited validity index, previous
research has focused on PAHs isomer pair ratios of variable
physicochemical properties in source identification. The objective of
this investigation was to determine the empirical validity of Pearson
Correlation Coefficient (PCC) and Cluster Analysis (CA) in PAHs
source identification along soil samples of different land uses.
Therefore, 16 PAHs grouped, as Endocrine Disruption Substances
(EDSs) were determined in 10 sample stations in top and sub soils
seasonally. PAHs was determined the use of Varian 300 gas
chromatograph interfaced with flame ionization detector. Instruments
and reagents used are of standard and chromatographic grades
respectively. PCC and CA results showed that the classification of
PAHs along pyrolitic and petrogenic organics used in source
signature is about the predominance PAHs in environmental matrix.
Therefore, the distribution of PAHs in the studied stations revealed
the presence of trace quantities of the vast majority of the sixteen
PAHs, which may ultimately inhabit the actual source signature
authentication. Therefore, factors to be considered when evaluating
possible sources of PAHs could be; type and extent of bacterial
metabolism, transformation products/substrates, and environmental
factors such as salinity, pH, oxygen concentration, nutrients, light
intensity, temperature, co-substrates, and environmental medium are
hereby recommended as factors to be considered when evaluating
possible sources of PAHs.
Abstract: The purpose of the study was to examine lifelong
education for teachers as a tool for achieving effective teaching and
learning. Lifelong education enhances social inclusion, personal
development, citizenship, employability, teaching and learning,
community and the nation. It is imperative that the teacher needs to
update his knowledge regularly to be able to perform optimally, since
he has a major position in the inculcation of desirable elements in
students, and the challenges of lifelong education were also
discussed. Descriptive survey design was adopted for the study. A
simple random sampling technique was used to select 80 teachers as
sample from a population of 105 senior secondary school teachers in
Makurdi Local Government Area of Benue State. A 20-item self
designed questionnaire subjected to expert validation and reliability
was used to collect data. The reliability Alpha coefficient of 0.87 was
established using Cronbach’s Alpha technique, mean scores and
standard deviation were used to answer the 2 research questions
while chi-square was used to analyse data for the 2 null hypotheses,
which states that lifelong education for teachers is not a significant
tool for achieving effective teaching and lifelong education for
teachers does not significantly impact on effective learning. The
findings of the study revealed that, lifelong education for teachers can
be used as a tool for achieving effective teaching and learning, and
the study recommended among others that government, organizations
and individuals should in collaboration put lifelong education
programmes for teachers on the priority list. The paper concluded
that the strategic position of lifelong education for teachers towards
enhanced teaching, learning and the production of quality manpower
in the society makes it imperative for all hands to be on “deck” to
support the programme financially and otherwise.
Abstract: In turbulent modern economy, the companies need to
properly manage their business processes. Well-defined and stable
business processes ensure security of crucial data and applications,
and provide a quality product or service to the end customer. On the
other side, constant changes on the market, new regulatory
provisions, and emerging new technologies require the need of
issuing prompt and effective changes of business process. In this
article, we explore the use of agile principles in working with
business process management (BPM) solutions. We deal with
difficulties in BPM development cycle, review the benefits of using
agility, and choose the basic agile principles that ensure the success
of a BPM project.
Abstract: The objective of the paper is a numerical study of heat
transfer between perforated metal plates and the surrounding air
flows. Different perforation structures can nowadays be found in
various industrial products. Besides improving the mechanical
properties, the perforations can intensify the heat transfer as well. The
heat transfer coefficient depends on a wide range of parameters such
as type of perforation, size, shape, flow properties of the surrounding
air etc. The paper was focused on three different perforation
structures which have been investigated from the point of the view of
the production in the previous studies. To determine the heat
coefficients and the Nusselt numbers, the numerical simulation
approach was adopted. The calculations were performed using the
OpenFOAM software. The three-dimensional, unstable, turbulent and
incompressible air flow around the perforated surface metal plate was
considered.
Abstract: Increasingly complex modern power systems require
stability, especially for transient and small disturbances. Transient
stability plays a major role in stability during fault and large
disturbance. This paper compares a power system stabilizer (PSS)
and static Var compensator (SVC) to improve damping oscillation
and enhance transient stability. The effectiveness of a PSS connected
to the exciter and/or governor in damping electromechanical
oscillations of isolated synchronous generator was tested. The SVC
device is a member of the shunt FACTS (flexible alternating current
transmission system) family, utilized in power transmission systems.
The designed model was tested with a multi-machine system
consisting of four machines six bus, using MATLAB/SIMULINK
software. The results obtained indicate that SVC solutions are better
than PSS.
Abstract: Temperature regulating system by gaseous nitrogen is
of importance to the space environment simulator, which keeps the
shrouds in the temperature range from -150°C to +150°C. Liquid
nitrogen spray equipment is one of the most critical parts in the
temperature regulating system by gaseous nitrogen. Y type jet
atomizer and internal mixing atomizer of the liquid nitrogen spray
equipment are studied in this paper, 2D/3D atomizer model was
established and grid division was conducted respectively by the
software of Catia and ICEM. Based on the above preparation,
numerical simulation on the spraying process of the atomizer by
FLUENT is performed. Using air and water as the medium,
comparison between the tests and numerical simulation was conducted
and the results of two ways match well. Hence, it can be conclude that
this atomizer model can be applied in the numerical simulation of
liquid nitrogen spray equipment.
Abstract: The garment manufacturing industry involves
sequential processes that are subjected to uncontrollable variations.
The industry depends on the skill of labour in handling the varieties
of fabrics and accessories, machines, as well as complicated sewing
operation. Due to these reasons, garment manufacturers have created
systems to monitor and to control the quality of the products on a
regular basis by conducting quality approaches to minimize variation.
With that, the aim of this research has been to ascertain the quality
approaches deployed by Malaysian garment manufacturers in three
key areas - quality systems and tools; quality control and types of
inspection; as well as sampling procedures chosen for garment
inspection. Besides, the focus of this research was to distinguish the
quality approaches adopted by companies that supplied finished
garments to both domestic and international markets. Feedback from
each company representative has been obtained via online survey,
which comprised of five sections and 44 questions on the
organizational profile and the quality approaches employed in the
garment industry. As a result, the response rate was 31%. The results
revealed that almost all companies have established their own
mechanism of process control by conducting a series of quality
inspections for daily production, either it was formally set up or
otherwise. In addition, quality inspection has been the predominant
quality control activity in the garment manufacturing, while the level
of complexity of these activities was substantially dictated by the
customers. Moreover, AQL-based sampling was utilized by
companies dealing with exports, whilst almost all the companies that
only concentrated on the domestic market were comfortable using
their own sampling procedures for garment inspection. Hence, this
research has provided insights into the implementation of a number
of quality approaches that were perceived as important and useful in
the garment manufacturing sector, which is truly labour-intensive.
Abstract: South Africa is in its post-industrial era moving from
the primary and secondary sector to the tertiary sector. The study
investigated the impact of the disaggregated energy consumption
(coal, oil, and electricity) on the primary, secondary and tertiary
sectors of the economy between 1980 and 2012 in South Africa.
Using vector error correction model, it was established that South
Africa is an energy dependent economy, and that energy (especially
electricity and oil) is a limiting factor of growth. This implies that
implementation of energy conservation policies may hamper
economic growth. Output growth is significantly outpacing energy
supply, which has necessitated load shedding. To meet up the excess
energy demand, there is a need to increase the generating capacity
which will necessitate increased investment in the electricity sector as
well as strategic steps to increase oil production. There is also need to
explore more renewable energy sources, in order to meet the growing
energy demand without compromising growth and environmental
sustainability. Policy makers should also pursue energy efficiency
policies especially at sectoral level of the economy.
Abstract: Annihilations, phase shifts, scattering lengths and
elastic cross sections of low energy positrons scattering from
magnesium atoms were studied using the least-squares variational
method (LSVM). The possibility of positron binding to the
magnesium atoms is investigated. A trial wave function is suggested
to represent e+-Mg elastic scattering and scattering parameters were
derived to estimate the binding energy and annihilation rates. The
trial function is taken to depend on several adjustable parameters, and
is improved iteratively by increasing the number of terms. The
present results have the same behavior as reported semi-empirical,
theoretical and experimental results. Especially, the estimated
positive scattering length supports the possibility of positronmagnesium
bound state system that was confirmed in previous
experimental and theoretical work.
Abstract: In this article, we used the residual correction method
to deal with transient thermoelastic problems with a hollow spherical
region when the continuum medium possesses spherically isotropic
thermoelastic properties. Based on linear thermoelastic theory, the
equations of hyperbolic heat conduction and thermoelastic motion
were combined to establish the thermoelastic dynamic model with
consideration of the deformation acceleration effect and non-Fourier
effect under the condition of transient thermal shock. The approximate
solutions of temperature and displacement distributions are obtained
using the residual correction method based on the maximum principle
in combination with the finite difference method, making it easier and
faster to obtain upper and lower approximations of exact solutions.
The proposed method is found to be an effective numerical method
with satisfactory accuracy. Moreover, the result shows that the effect
of transient thermal shock induced by deformation acceleration is
enhanced by non-Fourier heat conduction with increased peak stress.
The influence on the stress increases with the thermal relaxation time.
Abstract: A clay soil classified as A-7-6 and CH soil according
to AASHTO and unified soil classification system respectively, was
stabilized using A-3 soil (AASHTO soil classification system). The
clay soil was replaced with 0%, 10%, 20%, to 100% A-3 soil,
compacted at both British Standard Light (BSL) and British Standard
Heavy (BSH) compaction energy levels and using Unconfined
Compressive Strength (UCS) as evaluation criteria. The Maximum
Dry Density (MDD) of the treated soils at both the BSL and BSH
compaction energy levels showed increase from 0% to 40% A-3 soil
replacement after which the values reduced to 100% replacement.
The trend of the Optimum Moisture Content (OMC) with varied A-3
soil replacement was similar to that of MDD but in a reversed order.
The OMC reduced from 0% to 40% A-3 soil replacement after which
the values increased to 100% replacement. This trend was attributed
to the observed reduction in void ratio from 0% to 40% replacement
after which the void ratio increased to 100% replacement. The
maximum UCS for the soil at varied A-3 soil replacement increased
from 272 and 770 kN/m2 for BSL and BSH compaction energy level
at 0% replacement to 295 and 795 kN/m2 for BSL and BSH
compaction energy level respectively at 10% replacement after which
the values reduced to 22 and 60 kN/m2 for BSL and BSH compaction
energy level respectively at 70% replacement. Beyond 70%
replacement, the mixtures could not be moulded for UCS test.
Abstract: The relationship dependence between RSS and distance
in an enclosed environment is an important consideration because it is
a factor that can influence the reliability of any localization algorithm
founded on RSS. Several algorithms effectively reduce the variance of
RSS to improve localization or accuracy performance. Our proposed
algorithm essentially avoids this pitfall and consequently, its high
adaptability in the face of erratic radio signal. Using 3 anchors in
close proximity of each other, we are able to establish that RSS can be
used as reliable indicator for localization with an acceptable degree of
accuracy. Inherent in this concept, is the ability for each prospective
anchor to validate (guarantee) the position or the proximity of the
other 2 anchors involved in the localization and vice versa. This
procedure ensures that the uncertainties of radio signals due to
multipath effects in enclosed environments are minimized. A major
driver of this idea is the implicit topological relationship among
sensors due to raw radio signal strength. The algorithm is an area
based algorithm; however, it does not trade accuracy for precision
(i.e the size of the returned area).
Abstract: The growth in the demand of electrical energy is
leading to load on the Power system which increases the occurrence
of frequent oscillations in the system. The reason for the oscillations
is due to the lack of damping torque which is required to dominate
the disturbances of Power system. By using FACT devices, such as
Unified Power Flow Controller (UPFC) can control power flow,
reduce sub-synchronous resonances and increase transient stability.
Hence, UPFC is used to damp the oscillations occurred in Power
system. This research focuses on adapting the neuro fuzzy controller
for the UPFC design by connecting the infinite bus (SMIB - Single
machine Infinite Bus) to a linearized model of synchronous machine
(Heffron-Phillips) in the power system. This model gains the
capability to improve the transient stability and to damp the
oscillations of the system.
Abstract: Here, we have shown the reaction of [Cr(ArN(CH2)3NAr)2Cl2] (1) where (Ar = 2,6-Pri
2C6H3) and in presence of NaCp (2) (Cp= C5H5 = cyclopentadien), with a center
coordination η5 interaction between Cp as co-ligand and chromium
metal center, for optimization we used density functional theory
(DFT), under methods, explicitly including electrons correlations, for
the final calculations as MB3LYP (Becke) (Lee–Yang–Parr) level of
theory we used to obtain more exact results. This complex was
calculated as electronic energy for molecular system, because the
calculation accounting all electrons correlations interactions. The
optimised of [Cr(ArN(CH2)3NAr)2(η5-Cp)] (Ar = 2,6-Pri2C6H3 and Cp = C5H5) was found to be thermally stable. By using Dewar-Chatt-Duncanson model, as a basis of the molecular orbital (MO) analysis
and showed the highest occupied molecular orbital (HOMO) and
lowest occupied molecular orbital LUMO.
Abstract: Electronic mediums such as websites, feeds, blogs and
social media sites are on a daily basis influencing our decision
making, are improving our productivity and are shaping futures of
many consumers and service/product providers. This research
identifies that both customers and business providers heavily rely on
smart phone applications. Based on this, mobile applications
available on iTunes store were studied. It was identified that fruit and
vegetable related applications used by consumers can broadly be
categorized into purchase applications, diaries, tracking health
applications, trip farm location and cooking applications. On the
other hand, applications used by farmers can broadly be classified as:
weather tracking, pests / fertilizer applications and general social
media applications such as Facebook. To blur this farmer-consumer
application divide, our research utilizes Context Specific
eTransformation Framework and based on it identifies characteristic
future consumer-farmer applications will need to have so that the
current divide can be narrowed and consequently better farmerconsumer
supply chain link established.