Abstract: This paper is concerned with the single-item
continuous review inventory system in which demand is stochastic
and discrete. The budget consumed for purchasing the ordered items
is not restricted but it incurs extra cost when exceeding specific
value. The unit purchasing price depends on the quantity ordered
under the all-units discounts cost structure. In many actual systems,
the budget as a resource which is occupied by the purchased items is
limited and the system is able to confront the resource shortage by
charging more costs. Thus, considering the resource shortage costs as
a part of system costs, especially when the amount of resource
occupied by the purchased item is influenced by quantity discounts,
is well motivated by practical concerns. In this paper, an optimization
problem is formulated for finding the optimal (r, Q) policy, when the
system is influenced by the budget limitation and a discount pricing
simultaneously. Properties of the cost function are investigated and
then an algorithm based on a one-dimensional search procedure is
proposed for finding an optimal (r, Q) policy which minimizes the
expected system costs.
Abstract: The spindle system is one of the most important
components of machine tool. The dynamic properties of the spindle
affect the machining productivity and quality of the work pieces.
Thus, it is important and necessary to determine its dynamic
characteristics of spindles in the design and development in order to
avoid forced resonance. The finite element method (FEM) has been
adopted in order to obtain the dynamic behavior of spindle system.
For this reason, obtaining the Campbell diagrams and determining the
critical speeds are very useful to evaluate the spindle system
dynamics. The unbalance response of the system to the center of
mass unbalance at the cutting tool is also calculated to investigate the
dynamic behavior. In this paper, we used an ANSYS Parametric
Design Language (APDL) program which based on finite element
method has been implemented to make the full dynamic analysis and
evaluation of the results. Results show that the calculated critical
speeds are far from the operating speed range of the spindle, thus, the
spindle would not experience resonance, and the maximum
unbalance response at operating speed is still with acceptable limit.
ANSYS Parametric Design Language (APDL) can be used by spindle
designer as tools in order to increase the product quality, reducing
cost, and time consuming in the design and development stages.
Abstract: In this communication, a low-cost circularly
polarized wire antenna exhibiting improved gain performance for
Dedicated Short Range Communications (DSRC), vehicle-to-vehicle
(V2V) and vehicle-to-infrastructure (V2I) communications is
presented. The proposed antenna comprises a Y-shaped quarterwavelength
monopole antenna surrounded by two iterations of eight
conductive arched walls acting as parasitic elements to enhance the
overall antenna gain and to shape the radiation pattern in the H-plane.
A hemispherical radome shell is added to protect the antenna
structure and its effect on the antenna performance is discussed. The
designed antenna demonstrates antenna gain of 8.2 dB with
omnidirectional far-field radiation pattern in the H-plane. The gain of
the proposed antenna is also compared with the characteristic of the
stand-alone Y-shaped monopole to highlight the advantages of the
proposed approach.
Abstract: This study analyzes the critical gaps in the
architecture of European stability and the expected role of the
banking union as the new important step towards completing the
Economic and Monetary Union that should enable the creation of
safe and sound financial sector for the euro area market. The single
rulebook together with the Single Supervisory Mechanism and the
Single Resolution Mechanism - as two main pillars of the banking
union, should provide a consistent application of common rules and
administrative standards for supervision, recovery and resolution of
banks – with the final aim of replacing the former bail-out practice
with the bail-in system through which possible future bank failures
would be resolved by their own funds, i.e. with minimal costs for
taxpayers and real economy. In this way, the vicious circle between
banks and sovereigns would be broken. It would also reduce the
financial fragmentation recorded in the years of crisis as the result of
divergent behaviors in risk premium, lending activities and interest
rates between the core and the periphery. In addition, it should
strengthen the effectiveness of monetary transmission channels, in
particular the credit channels and overflows of liquidity on the money
market which, due to the fragmentation of the common financial
market, has been significantly disabled in period of crisis. However,
contrary to all the positive expectations related to the future
functioning of the banking union, major findings of this study
indicate that characteristics of the economic system in which the
banking union will operate should not be ignored. The euro area is an
integration of strong and weak entities with large differences in
economic development, wealth, assets of banking systems, growth
rates and accountability of fiscal policy. The analysis indicates that
low and unbalanced economic growth remains a challenge for the
maintenance of financial stability and this problem cannot be
resolved just by a single supervision. In many countries bank assets
exceed their GDP by several times and large banks are still a matter
of concern, because of their systemic importance for individual
countries and the euro zone as a whole. The creation of the Single
Supervisory Mechanism and the Single Resolution Mechanism is a
response to the European crisis, which has particularly affected
peripheral countries and caused the associated loop between the
banking crisis and the sovereign debt crisis, but has also influenced
banks’ balance sheets in the core countries, as the result of crossborder
capital flows. The creation of the SSM and the SRM should
prevent the similar episodes to happen again and should also provide
a new opportunity for strengthening of economic and financial
systems of the peripheral countries. On the other hand, there is a
potential threat that future focus of the ECB, resolution mechanism
and other relevant institutions will be extremely oriented towards
large and significant banks (whereby one half of them operate in the
core and most important euro area countries), and therefore it remains
questionable to what extent will the common resolution funds will be used for rescue of less important institutions. Recent geopolitical
developments will be the optimal indicator to show whether the
previously established mechanisms are sufficient enough to maintain
the adequate financial stability in the euro area market.
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: 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: A lower consumption of thermal energy will
contribute not only to a reduction in the running costs, but also in the
reduction of pollutant emissions that contribute to the greenhouse
effect. Cogeneration or CHP (Combined Heat and Power) is the
system that produces power and usable heat simultaneously by
decreasing the pollutant emissions and increasing the efficiency.
Combined production of mechanical or electrical and thermal energy
using a simple energy source, such as oil, coal, natural or liquefied
gas, biomass or the sun; affords remarkable energy savings and
frequently makes it possible to operate with greater efficiency when
compared to a system producing heat and power separately. This
study aims to bring out the contributions of cogeneration systems to
the environment and sustainability by saving the energy and reducing
the emissions. In this way we made a comprehensive investigation in
the literature by focusing on the environmental aspects of the
cogeneration systems. In the light of these studies we reached that,
cogeneration systems must be consider in sustainability and their
benefits on protecting the ecology must be investigated.
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 introduces a boost converter with a new
active snubber cell. In this circuit, all of the semiconductor
components in the converter softly turns on and turns off with the
help of the active snubber cell. Compared to the other converters, the
proposed converter has advantages of size, number of components
and cost. The main feature of proposed converter is that the extra
voltage stresses do not occur on the main switches and main diodes.
Also, the current stress on the main switch is acceptable level.
Moreover, the proposed converter can operates under light load
conditions and wide input line voltage. In this study, the operating
principle of the proposed converter is presented and its operation is
verified with the Proteus simulation software for a 1 kW and 100 kHz
model.
Abstract: Phonocardiography is important in appraisal of
congenital heart disease and pulmonary hypertension as it reflects the
duration of right ventricular systoles. The systolic murmur in patients
with intra-cardiac shunt decreases as pulmonary hypertension
develops and may eventually disappear completely as the pulmonary
pressure reaches systemic level. Phonocardiography and auscultation
are non-invasive, low-cost, and accurate methods to assess heart
disease. In this work an objective signal processing tool to extract
information from phonocardiography signal using Wavelet is
proposed to classify the murmur as normal or abnormal. Since the
feature vector is large, a Binary Particle Swarm Optimization (PSO)
with mutation for feature selection is proposed. The extracted
features improve the classification accuracy and were tested across
various classifiers including Naïve Bayes, kNN, C4.5, and SVM.
Abstract: The MEMS pressure sensor has been introduced and
presented in this paper. The types of pressure sensor and its theory of
operation are also included. The latest MEMS technology, the
fabrication processes of pressure sensor are explored and discussed.
Besides, various device applications of pressure sensor such as tire
pressure-monitoring system, diesel particulate filter and others are
explained. Due to further miniaturization of the device nowadays, the
pressure sensor with nanotechnology (NEMS) is also reviewed. The
NEMS pressure sensor is expected to have better performance as well
as lower in its cost. It has gained an excellent popularity in many
applications.
Abstract: In recent years, fire accidents have been steadily
increased and the amount of property damage caused by the accidents
has gradually raised. Damaging building structure, fire incidents bring
about not only such property damage but also strength degradation and
member deformation. As a result, the building structure undermines its
structural ability. Examining the degradation and the deformation is
very important because reusing the building is more economical than
reconstruction. Therefore, engineers need to investigate the strength
degradation and member deformation well, and make sure that they
apply right rehabilitation methods. This study aims at evaluating
deformation characteristics of fire damaged and rehabilitated normal
strength concrete beams through both experiments and finite element
analyses. For the experiments, control beams, fire damaged beams and
rehabilitated beams are tested to examine deformation characteristics.
Ten test beam specimens with compressive strength of 21MPa are
fabricated and main test variables are selected as cover thickness of
40mm and 50mm and fire exposure time of 1 hour or 2 hours. After
heating, fire damaged beams are air-recurred for 2 months and
rehabilitated beams are repaired with polymeric cement mortar after
being removed the fire damaged concrete cover. All beam specimens
are tested under four points loading. FE analyses are executed to
investigate the effects of main parameters applied to experimental
study. Test results show that both maximum load and stiffness of the
rehabilitated beams are higher than those of the fire damaged beams.
In addition, predicted structural behaviors from the analyses also show
good rehabilitation effect and the predicted load-deflection curves are
similar to the experimental results. For the further, the proposed
analytical method can be used to predict deformation characteristics of
fire damaged and rehabilitated concrete beams without suffering from
time and cost consuming of experimental process.
Abstract: Nanotechnology has become the world attention in
various applications including the solar cells devices due to the
uniqueness and benefits of achieving low cost and better
performances of devices. Recently, thin film solar cells such as
Cadmium Telluride (CdTe), Copper-Indium-Gallium-diSelenide
(CIGS), Copper-Zinc-Tin-Sulphide (CZTS), and Dye-Sensitized
Solar Cells (DSSC) enhanced by nanotechnology have attracted
much attention. Thus, a compilation of nanotechnology devices
giving the progress in the solar cells has been presented. It is much
related to nanoparticles or nanocrystallines, carbon nanotubes, and
nanowires or nanorods structures.
Abstract: The economic use and ease of construction of profiled
deck composite slab is marred with the complex and un-economic
strength verification required for the serviceability and general safety
considerations. Beside these, albeit factors such as shear span length,
deck geometries and mechanical frictions greatly influence the
longitudinal shear strength, that determines the ultimate strength of
profiled deck composite slab, and number of methods available for its
determination; partial shear and slope-intercept are the two methods
according to Euro-code 4 provision. However, the complexity
associated with shear behavior of profiled deck composite slab, the
use of these methods in determining the load carrying capacities of
such slab yields different and conflicting values. This couple with the
time and cost constraint associated with the strength verification is a
source of concern that draws more attentions nowadays, the issue is
critical. Treating some of these known shear strength influencing
factors as random variables, the load carrying capacity violation of
profiled deck composite slab from the use of the two-methods
defined according to Euro-code 4 are determined using reliability
approach, and comparatively studied. The study reveals safety values
from the use of m-k method shows good standing compared with that
from the partial shear method.
Abstract: The efficient and economic allocation of resources is
one main goal in the field of production planning and control.
Nowadays, a new variable gains in importance throughout the
planning process: Energy. Energy-efficiency has already been widely
discussed in literature, but with a strong focus on reducing the overall
amount of energy used in production. This paper provides a brief
systematic approach, how energy-supply-orientation can be used for
an energy-cost-efficient production planning and thus combining the
idea of energy-efficiency and energy-flexibility.
Abstract: Superabsorbent polymers received much attention and
are used in many fields because of their superior characters to
traditional absorbents, e.g., sponge and cotton. So, it is very
important but challenging to prepare highly and fast-swelling
superabsorbents. A reliable, efficient and low-cost technique for
removing heavy metal ions from wastewater is the adsorption using
bio-adsorbents obtained from biological materials, such as
polysaccharides-based hydrogels superabsorbents. In this study, novel multi-functional superabsorbent composites
type semi-interpenetrating polymer networks (Semi-IPNs) were
prepared via graft polymerization of acrylamide onto chitosan
backbone in presence of gelatin, CTS-g-PAAm/Ge, using potassium
persulfate and N,N’-methylene bisacrylamide as initiator and
crosslinker, respectively. These hydrogels were also partially
hydrolyzed to achieve superabsorbents with ampholytic properties
and uppermost swelling capacity. The formation of the grafted
network was evidenced by Fourier Transform Infrared Spectroscopy
(ATR-FTIR) and Thermogravimetric Analysis (TGA). The porous
structures were observed by Scanning Electron Microscope (SEM).
From TGA analysis, it was concluded that the incorporation of the Ge
in the CTS-g-PAAm network has marginally affected its thermal
stability. The effect of gelatin content on the swelling capacities of
these superabsorbent composites was examined in various media
(distilled water, saline and pH-solutions). The water absorbency was
enhanced by adding Ge in the network, where the optimum value was
reached at 2 wt. % of Ge. Their hydrolysis has not only greatly
optimized their absorption capacity but also improved the swelling
kinetic.These materials have also showed reswelling ability. We
believe that these super-absorbing materials would be very effective
for the adsorption of harmful metal ions from wastewater.
Abstract: Lead time is a critical measure of a supply chain's
performance. It impacts both the customer satisfactions as well as the
total cost of inventory. This paper presents the result of a study on the
analysis of the customer order lead-time for a multinational company.
In the study, the lead time was divided into three stages respectively:
order entry, order fulfillment, and order delivery. A sample of size 2,425 order lines was extracted from the
company's records to use for this study. The sample data entails
information regarding customer orders from the time of order entry
until order delivery. Data regarding the lead time of each stage for
different orders were also provided. Summary statistics on lead time
data reveals that about 30% of the orders were delivered later than the
scheduled due date. The result of the multiple linear regression
analysis technique revealed that component type, logistics parameter,
order size and the customer type have significant impacts on lead
time. Data analysis on the stages of lead time indicates that stage 2
consumed over 50% of the lead time. Pareto analysis was made to
study the reasons for the customer order delay in each stage.
Recommendation was given to resolve the problem.
Abstract: In this paper, we present a four-step ortho-rectification
procedure for real-time geo-referencing of video data from a low-cost
UAV equipped with a multi-sensor system. The basic procedures for
the real-time ortho-rectification are: (1) decompilation of the video
stream into individual frames; (2) establishing the interior camera
orientation parameters; (3) determining the relative orientation
parameters for each video frame with respect to each other; (4)
finding the absolute orientation parameters, using a self-calibration
bundle and adjustment with the aid of a mathematical model. Each
ortho-rectified video frame is then mosaicked together to produce a
mosaic image of the test area, which is then merged with a well
referenced existing digital map for the purpose of geo-referencing
and aerial surveillance. A test field located in Abuja, Nigeria was
used to evaluate our method. Video and telemetry data were collected
for about fifteen minutes, and they were processed using the four-step
ortho-rectification procedure. The results demonstrated that the
geometric measurement of the control field from ortho-images is
more accurate when compared with those from original perspective
images when used to pin point the exact location of targets on the
video imagery acquired by the UAV. The 2-D planimetric accuracy
when compared with the 6 control points measured by a GPS receiver
is between 3 to 5 metres.
Abstract: In present global scenario, aluminum alloys are
coining the attention of many innovators as competing structural
materials for automotive and space applications. Comparing to other
challenging alloys, especially, 7xxx series aluminum alloys have
been studied seriously because of benefits such as moderate strength;
better deforming characteristics and affordable cost. It is expected
that substitution of aluminum alloys for steels will result in great
improvements in energy economy, durability and recyclability.
However, it is necessary to improve the strength and the formability
levels at low temperatures in aluminum alloys for still better
applications. Aluminum–Zinc–Magnesium with or without other
wetting agent denoted as 7XXX series alloys are medium strength
heat treatable alloys. In addition to Zn, Mg as major alloying
additions, Cu, Mn and Si are the other solute elements which
contribute for the improvement in mechanical properties by suitable
heat treatment process. Subjecting to suitable treatments like age
hardening or cold deformation assisted heat treatments; known as low
temperature thermomechanical treatments (LTMT) the challenging
properties might be incorporated. T6 is the age hardening or
precipitation hardening process with artificial aging cycle whereas T8
comprises of LTMT treatment aged artificially with X% cold
deformation. When the cold deformation is provided after solution
treatment, there is increase in hardness related properties such as
wear resistance, yield and ultimate strength, toughness with the
expense of ductility. During precipitation hardening both hardness
and strength of the samples are increasing. The hardness value may
further improve when room temperature deformation is positively
supported with age hardening known as thermomechanical treatment.
It is intended to perform heat treatment and evaluate hardness, tensile
strength, wear resistance and distribution pattern of reinforcement in
the matrix. 2 to 2.5 and 3 to 3.5 times increase in hardness is reported
in age hardening and LTMT treatments respectively as compared to
as-cast composite. There was better distribution of reinforcements in
the matrix, nearly two fold increase in strength levels and up to 5
times increase in wear resistance are also observed in the present
study.