Abstract: Excessive vibration means increased wear, increased
repair efforts, bad product selection & quality and high energy
consumption. This may be sometimes experienced by cavitation or
suction/discharge recirculation which could occur only when net
positive suction head available NPSHA drops below the net positive
suction head required NPSHR. Cavitation can cause axial surging, if it
is excessive, will damage mechanical seals, bearings, possibly other
pump components frequently, and shorten the life of the impeller.
Efforts have been made to explain Suction Energy (SE), Specific
Speed (Ns), Suction Specific Speed (Nss), NPSHA, NPSHR & their
significance, possible reasons of cavitation /internal recirculation, its
diagnostics and remedial measures to arrest and prevent cavitation in
this paper. A case study is presented by the author highlighting that
the root cause of unwanted noise and vibration is due to cavitation,
caused by high specific speeds or inadequate net- positive suction
head available which results in damages to material surfaces of
impeller & suction bells and degradation of machine performance, its
capacity and efficiency too. Author strongly recommends revisiting
the technical specifications of CW pumps to provide sufficient NPSH
margin ratios >1.5, for future projects and Nss be limited to 8500 -
9000 for cavitation free operation.
Abstract: This paper explored the challenges faced by the
management of a Ghanaian state enterprise in managing conflicts and
disturbances associated with its attempt to implement new work
practices to enhance its capability to operate as a commercial entity.
The purpose was to understand the extent to which organizational
involvement, consistency and adaptability influence employees’
consumption of new work practices in transforming the
organization’s organizational activity system. Using selfadministered
questionnaires, data were collected from one hundred
and eighty (180) employees and analyzed using both descriptive and
inferential statistics. The results showed that constraints in
organizational involvement and adaptability prevented the positive
consumption of new work practices by employees in the
organization. It is also found that the organization’s employees failed
to consume the new practices being implemented, because they
perceived the process as non-involving, and as such, did not
encourage the development of employee capability, empowerment,
and teamwork. The study concluded that the failure of the
organization’s management to create opportunities for organizational
learning constrained its ability to get employees consume the new
work practices, which situation could have facilitated the
organization’s capabilities of operating as a commercial entity.
Abstract: In order to retrieve images efficiently from a large
database, a unique method integrating color and texture features
using genetic programming has been proposed. Opponent color
histogram which gives shadow, shade, and light intensity invariant
property is employed in the proposed framework for extracting color
features. For texture feature extraction, fast discrete curvelet
transform which captures more orientation information at different
scales is incorporated to represent curved like edges. The recent
scenario in the issues of image retrieval is to reduce the semantic gap
between user’s preference and low level features. To address this
concern, genetic algorithm combined with relevance feedback is
embedded to reduce semantic gap and retrieve user’s preference
images. Extensive and comparative experiments have been conducted
to evaluate proposed framework for content based image retrieval on
two databases, i.e., COIL-100 and Corel-1000. Experimental results
clearly show that the proposed system surpassed other existing
systems in terms of precision and recall. The proposed work achieves
highest performance with average precision of 88.2% on COIL-100
and 76.3% on Corel, the average recall of 69.9% on COIL and 76.3%
on Corel. Thus, the experimental results confirm that the proposed
content based image retrieval system architecture attains better
solution for image retrieval.
Abstract: In this paper, a modified Wilkinson power divider for
GSM application is presented. The quarter–wavelength microstrip
lines in the conventional Wilkinson power divider (WPD) are
replaced by one-eighth wavelength transmission line. Wilkinson
power divider is designed using λ/4 and λ/8 transmission line. It has
the operating frequency of 915 MHz which is used in the GSM
standard. The proposed Wilkinson Power Divider is designed using
the simulation tool Advanced Design System. The results of λ/8
transmission line are very close to the results of λ/4 transmission line.
The isolation loss of λ/8 transmission line is improved by introducing
a capacitor between the output ports. The proposed Wilkinson power
divider has the best return loss of greater than -10 dB and isolation
loss of -15.25 dB. The λ/8 transmission line Wilkinson power divider
has the reduced size of 53.9 percentages than λ/4 transmission line
WPD. The proposed design has simple structure, better isolation loss
and good insertion loss.
Abstract: The paper deals with possibilities of increase train
capacity by using a new type of railway wagon. In the first part is
created a mathematical model to calculate the capacity of the train.
The model is based on the main limiting parameters of the train -
maximum number of axles per train, maximum gross weight of train,
maximum length of train and number of TEUs per one wagon. In the
second part is the model applied to four different model trains with
different composition of the train set and three different average
weights of TEU and a train consisting of a new type of wagons. The
result is to identify where the carrying capacity of the original trains
is higher, respectively less than a capacity of train consisting of a new
type of wagons.
Abstract: Objective: Safety and efficacy of Ahmed glaucoma
valve implantation for the management of uveitis induced glaucoma
evaluated on the five dogs with uncontrollable glaucoma. Materials
and Methods: Ahmed Glaucoma Valve (AGV®; New World
Medical, Rancho Cucamonga, CA, USA) is a flow restrictive, nonobstructive
self-regulating valve system. Preoperative ocular
evaluation included direct ophthalmoscopy and measurement of the
intraocular pressure (IOP). The implant was examined and primed
prior to implantation. The selected site of the valve implantation was
the superior quadrant between the superior and lateral rectus muscles.
A fornix-based incision was made through the conjunectiva and
Tenon’s capsule. A pocket is formed by blunt dissection of Tenon’s
capsule from the episclera. The body of the implant was inserted into
the pocket with the leading edge of the device around 8-10 mm from
the limbus. Results: No post-operative complications were detected
in the operated eyes except a persistent corneal edema occupied the
upper half of the cornea in one case. Hyphaema was very mild and
seen only in two cases which resolved quickly two days after surgery.
Endoscopical evaluation for the operated eyes revealed a normal
ocular fundus with clearly visible optic papilla, tapetum and retinal
blood vessels. No evidence of hemorrhage, infection, adhesions or
retinal abnormalities was detected. Conclusion: Ahmed glaucoma
valve is safe and effective implant for treatment of uveitic glaucoma
in dogs.
Abstract: With the advancement of knowledge about the utility
and impact of sustainability, its feasibility has been explored into
different walks of life. Scientists, however; have established their
knowledge in four areas viz environmental, economic, social and
cultural, popularly termed as four pillars of sustainability. Aspects of
environmental and economic sustainability have been rigorously
researched and practiced and huge volume of strong evidence of
effectiveness has been founded for these two sub-areas. For the social
and cultural aspects of sustainability, dependable evidence of
effectiveness is still to be instituted as the researchers and
practitioners are developing and experimenting methods across the
globe. Therefore, the present research aimed to identify globally used
practices of social and cultural sustainability and through evidence
synthesis assess their outcomes to determine the effectiveness of
those practices. A PICO format steered the methodology which
included all populations, popular sustainability practices including
walkability/cycle tracks, social/recreational spaces, privacy, health &
human services and barrier free built environment, comparators
included ‘Before’ and ‘After’, ‘With’ and ‘Without’, ‘More’ and
‘Less’ and outcomes included Social well-being, cultural coexistence,
quality of life, ethics and morality, social capital, sense of
place, education, health, recreation and leisure, and holistic
development. Search of literature included major electronic
databases, search websites, organizational resources, directory of
open access journals and subscribed journals. Grey literature,
however, was not included. Inclusion criteria filtered studies on the
basis of research designs such as total randomization, quasirandomization,
cluster randomization, observational or single studies
and certain types of analysis. Studies with combined outcomes were
considered but studies focusing only on environmental and/or
economic outcomes were rejected. Data extraction, critical appraisal
and evidence synthesis was carried out using customized tabulation,
reference manager and CASP tool. Partial meta-analysis was carried
out and calculation of pooled effects and forest plotting were done.
As many as 13 studies finally included for final synthesis explained
the impact of targeted practices on health, behavioural and social
dimensions. Objectivity in the measurement of health outcomes
facilitated quantitative synthesis of studies which highlighted the
impact of sustainability methods on physical activity, Body Mass
Index, perinatal outcomes and child health. Studies synthesized
qualitatively (and also quantitatively) showed outcomes such as
routines, family relations, citizenship, trust in relationships, social
inclusion, neighbourhood social capital, wellbeing, habitability and
family’s social processes. The synthesized evidence indicates slight
effectiveness and efficacy of social and cultural sustainability on the
targeted outcomes. Further synthesis revealed that such results of this
study are due weak research designs and disintegrated implementations. If architects and other practitioners deliver their
interventions in collaboration with research bodies and policy
makers, a stronger evidence-base in this area could be generated.
Abstract: Digital images are widely used in computer
applications. To store or transmit the uncompressed images
requires considerable storage capacity and transmission bandwidth.
Image compression is a means to perform transmission or storage of
visual data in the most economical way. This paper explains about
how images can be encoded to be transmitted in a multiplexing
time-frequency domain channel. Multiplexing involves packing
signals together whose representations are compact in the working
domain. In order to optimize transmission resources each 4 × 4
pixel block of the image is transformed by a suitable polynomial
approximation, into a minimal number of coefficients. Less than
4 × 4 coefficients in one block spares a significant amount of
transmitted information, but some information is lost. Different
approximations for image transformation have been evaluated as
polynomial representation (Vandermonde matrix), least squares +
gradient descent, 1-D Chebyshev polynomials, 2-D Chebyshev
polynomials or singular value decomposition (SVD). Results have
been compared in terms of nominal compression rate (NCR),
compression ratio (CR) and peak signal-to-noise ratio (PSNR)
in order to minimize the error function defined as the difference
between the original pixel gray levels and the approximated
polynomial output. Polynomial coefficients have been later encoded
and handled for generating chirps in a target rate of about two
chirps per 4 × 4 pixel block and then submitted to a transmission
multiplexing operation in the time-frequency domain.
Abstract: Journal bearings used in IC engines are prone to premature
failures and are likely to fail earlier than the rated life due to
highly impulsive and unstable operating conditions and frequent
starts/stops. Vibration signature extraction and wear debris analysis
techniques are prevalent in industry for condition monitoring of
rotary machinery. However, both techniques involve a great deal of
technical expertise, time, and cost. Limited literature is available on
the application of these techniques for fault detection in reciprocating
machinery, due to the complex nature of impact forces that
confounds the extraction of fault signals for vibration-based analysis
and wear prediction. In present study, a simulation model was developed to investigate
the bearing wear behaviour, resulting because of different operating
conditions, to complement the vibration analysis. In current
simulation, the dynamics of the engine was established first, based on
which the hydrodynamic journal bearing forces were evaluated by
numerical solution of the Reynold’s equation. In addition, the
essential outputs of interest in this study, critical to determine wear
rates are the tangential velocity and oil film thickness between the
journals and bearing sleeve, which if not maintained appropriately,
have a detrimental effect on the bearing performance. Archard’s wear prediction model was used in the simulation to
calculate the wear rate of bearings with specific location information
as all determinative parameters were obtained with reference to crank
rotation. Oil film thickness obtained from the model was used as a
criterion to determine if the lubrication is sufficient to prevent contact
between the journal and bearing thus causing accelerated wear. A
limiting value of 1 μm was used as the minimum oil film thickness
needed to prevent contact. The increased wear rate with growing
severity of operating conditions is analogous and comparable to the
rise in amplitude of the squared envelope of the referenced vibration
signals. Thus on one hand, the developed model demonstrated its
capability to explain wear behaviour and on the other hand it also
helps to establish a co-relation between wear based and vibration
based analysis. Therefore, the model provides a cost effective and
quick approach to predict the impending wear in IC engine bearings
under various operating conditions.
Abstract: The purpose of this study is analyzing the relationship
between trust and social capital of people with using Social Network
Analysis. In this study, two aspects of social capital will be focused:
Bonding, homophilous social capital (BoSC), and Bridging,
heterophilous social capital (BrSC). These two aspects diverge each
other regarding to the social theories. The other concept of the study
is Trust (Tr), namely interpersonal trust, willing to ascribe good
intentions to and have confidence in the words and actions of other
people. In this study, the sample group, 61 people, was selected from
a private firm from the defense industry. The relation between
BoSC/BrSC and Tr is shown by using Social Network Analysis
(SNA) and statistical analysis with Likert type-questionnaire. The
results of the analysis show the Cronbach’s alpha value is 0.756 and
social capital values (BoSC/BrSC) is not correlated with Tr values of
the people.
Abstract: Genetic algorithm is widely used in optimization
problems for its excellent global search capabilities and highly parallel
processing capabilities; but, it converges prematurely and has a poor
local optimization capability in actual operation. Simulated annealing
algorithm can avoid the search process falling into local optimum. A
hybrid genetic algorithm based on simulated annealing is designed by
combining the advantages of genetic algorithm and simulated
annealing algorithm. The numerical experiment represents the hybrid
genetic algorithm can be applied to solve the function optimization
problems efficiently.
Abstract: Computer education is referred to as the knowledge
and ability to use computers and related technology efficiently, with a
range of skills covering levels from basic use to advance. Computer
continues to make an ever-increasing impact on all aspect of human
endeavours such as education. With numerous benefits of computer
education, what are the insights of students on computer education?
This study investigated the perception of senior secondary school
students on computer education in Federal Capital Territory (FCT),
Abuja, Nigeria. A sample of 7500 senior secondary schools students
was involved in the study, one hundred (100) private and fifty (50)
public schools within FCT. They were selected by using simple
random sampling technique. A questionnaire [PSSSCEQ] was
developed and validated through expert judgement and reliability coefficient
of 0.84 was obtained. It was used to gather relevant data on
computer education. Findings confirmed that the students in the FCT
had positive perception on computer education. Some factors were
identified that affect students’ perception on computer education. The
null hypotheses were tested using t-test and ANOVA statistical
analyses at 0.05 level of significance. Based on these findings, some
recommendations were made which include competent teachers
should be employed into all secondary schools. This will help
students to acquire relevant knowledge in computer education,
technological supports should be provided to all secondary schools;
this will help the users (students) to solve specific problems in
computer education and financial supports should be provided to
procure computer facilities that will enhance the teaching and the
learning of computer education.
Abstract: Mineral product, waste concrete (fine aggregates),
waste in the optical field, industry, and construction employ separators
to separate solids and classify them according to their size. Various
sorting machines are used in the industrial field such as those operating
under electrical properties, centrifugal force, wind power, vibration,
and magnetic force. Study on separators has been carried out to
contribute to the environmental industry. In this study, we perform
CFD analysis for understanding the basic mechanism of the separation
of waste concrete (fine aggregate) particles from air with a machine
built with a rotor with blades. In CFD, we first performed
two-dimensional particle tracking for various particle sizes for the
model with 1 degree, 1.5 degree, and 2 degree angle between each
blade to verify the boundary conditions and the method of rotating
domain method to be used in 3D. Then we developed 3D numerical
model with ANSYS CFX to calculate the air flow and track the
particles. We judged the capability of particle separation for given size
by counting the number of particles escaping from the domain toward
the exit among 10 particles issued at the inlet. We confirm that
particles experience stagnant behavior near the exit of the rotating
blades where the centrifugal force acting on the particles is in balance
with the air drag force. It was also found that the minimum particle
size that can be separated by the machine with the rotor is determined
by its capability to stay at the outlet of the rotor channels.
Abstract: Issues relating to the destructive phenomena that can
damage people and goods have returned to the centre of debate in
Italy with the increase in catastrophic episodes in recent years in a
country which is highly vulnerable to hydrological risk.
Environmental factors and geological and geomorphological
territorial characteristics play an important role in determining the
level of vulnerability and the natural tendency to risk. However, a
territory has also been subjected to the requirements of and
transformations of society and this brings other relevant factors. The
reasons for the increase in destructive phenomena are often to be
found in the territorial development models adopted. Stewardship of
the landscape and management of risk are related issues. This study aims to summarize the most relevant elements about
this connection and at the same time to clarify the role of
environmental risk assessment as a tool to aid in the sustainable
management of landscape. Finally, the study reflects on how regional
and urban planners deal with environmental risk and which aspects
should be monitored in order to adopt responsible and useful
interventions.
Abstract: The major environmental risk of soil pollution is the
contamination of groundwater by infiltration of organic and inorganic
pollutants which can cause a serious menace. To prevent this risk and
to protect the groundwater, we proceeded in this study to test the
reliability of a biosolid as barrier to prevent the migration of very
dangerous pollutants as ‘Cadmium’ through the different soil layers. In this study, we tried to highlight the effect of several parameters
such as: turbidity (different cycle of Hydration/Dehydration),
rainfall, effect of initial Cd(II) concentration and the type of soil.
These parameters allow us to find the most effective manner to
integrate this barrier in the soil. From the results obtained, we found a
significant effect of the barrier. Indeed, the recorded passing
quantities are lowest for the highest rainfall; we noted also that the
barrier has a better affinity towards higher concentrations; the most
retained amounts of cadmium has been in the top layer of the two
types of soil tested, while the lowest amounts of cadmium are
recorded in the bottom layers of soils.
Abstract: Context-aware technologies provide system
applications with the awareness of environmental conditions,
customer behaviours, object movements, etc. Further, with such
capability system applications can be smart to intelligently adapt their
responses to the changing conditions. In regard to business
operations, this promises businesses that their business processes can
run more intelligently, adaptively and flexibly, and thereby either
improve customer experience, enhance reliability of service delivery,
or lower operational cost, to make the business more competitive and
sustainable. Aiming at realising such context-aware business process
management, this paper firstly explores its potential benefit, and then
identifies some gaps between the current business process
management support and the expected. In addition, some preliminary
solutions are also discussed in regard to context definition, rule-based
process execution, run-time process evolution, etc. A framework is
also presented to give a conceptual architecture of context-aware
business process management system to guide system
implementation.
Abstract: Sewage sludge is a biomass resource that can create a
solid fuel and electricity. Utilizing sewage sludge as a renewable
energy can contribute to the reduction of greenhouse gases. In Japan,
the "National Plan for the Promotion of Biomass Utilization" and the
“Priority Plan for Social Infrastructure Development" were approved
at cabinet meetings in December 2010 and August 2012, respectively,
to promote the energy utilization of sewage sludge. This study
investigated costs and greenhouse gas emission in different sewage
sludge treatments with technologies for energy from sewage sludge.
Expenses were estimated based on capital costs and O&M costs
including energy consumption of solid fuel plants and biogas power
generation plants for sewage sludge. Results showed that the cost of
sludge digestion treatment with solid fuel technologies was 8% lower
than landfill disposal. The greenhouse gas emission of sludge
digestion treatment with solid fuel technologies was also 6,390t as
CO2 smaller than landfill disposal. Biogas power generation reduced
the electricity of a wastewater treatment plant by 30% and the cost by
5%.
Abstract: Green and renewable energy is getting extraordinary
consideration today, because of ecological concerns made by blazing
of fossil powers. Photovoltaic and wind power generation are the
basic decisions for delivering power in this respects. Producing
power by the sun based photovoltaic systems is known to the world,
yet control makers may get confounded to pick between on-grid and
off-grid systems. In this exploration work, an endeavor is made to
compare the off-grid (stand-alone) and on-grid (grid-connected)
frameworks. The work presents relative examination, between two
distinctive PV frameworks situated at V.V.P. Engineering College,
Rajkot. The first framework is 100 kW remain solitary and the
second is 60 kW network joined. The real-time parameters compared
are; output voltage, load current, power in-flow, power output,
performance ratio, yield factor, and capacity factor. The voltage
changes and the power variances in both frameworks are given
exceptional consideration and the examination is made between the
two frameworks to judge the focal points and confinements of both
the frameworks.
Abstract: Small-size and low-power sensors with sensing, signal
processing and wireless communication capabilities is suitable for the
wireless sensor networks. Due to the limited resources and battery
constraints, complex routing algorithms used for the ad-hoc networks
cannot be employed in sensor networks. In this paper, we propose
node-disjoint multi-path hexagon-based routing algorithms in wireless
sensor networks. We suggest the details of the algorithm and compare
it with other works. Simulation results show that the proposed scheme
achieves better performance in terms of efficiency and message
delivery ratio.
Abstract: The research investigates the causes of unemployment
in Namibia, Nigeria and South Africa and the role of Capital
Accumulation in reducing the unemployment profile of these
economies as proposed by the post-Keynesian economics. This is
conducted through extensive review of literature on the NAIRU
models and focused on the post-Keynesian view of unemployment
within the NAIRU framework. The NAIRU (non-accelerating
inflation rate of unemployment) model has become a dominant
framework used in macroeconomic analysis of unemployment. The
study views the post-Keynesian economics arguments that capital
accumulation is a major determinant of unemployment.
Unemployment remains the fundamental socio-economic challenge
facing African economies. It has been a burden to citizens of those
economies. Namibia, Nigeria, and South Africa are great African
nations battling with high unemployment rates. The high
unemployment rate in the country led the citizens to chase away
foreigners in the country claiming that they have taken away their
jobs. The study proposes there is a strong relationship between
capital accumulation and unemployment in Namibia, Nigeria, and
South Africa, and capital accumulation is responsible for high
unemployment rates in these countries. For the economies to achieve
steady state level of employment and satisfactory level of economic
growth and development, there is need for capital accumulation to
take place. The countries in the study have been selected after a
critical research and investigations. They are selected based on the
following criteria; African economies with high unemployment rates
above 15% and have about 40% of their workforce unemployed. This
level of unemployment is the critical level of unemployment in
Africa as expressed by International Labour Organization (ILO). And
finally, the African countries experience a slow growth in their Gross
fixed capital formation. Adequate statistical measures have been
employed using a time-series analysis in the study and the results
revealed that capital accumulation is the main driver of
unemployment performance in the chosen African countries. An
increase in the accumulation of capital causes unemployment to
reduce significantly. The results of the research work will be useful
and relevant to federal governments and ministries, departments and
agencies (MDAs) of Namibia, Nigeria and South Africa to resolve
the issue of high and persistent unemployment rates in their
economies which are great burden that slows growth and
development of developing economies. Also, the result can be useful
to World Bank, African Development Bank and International Labour
Organization (ILO) in their further research and studies on how to
tackle unemployment in developing and emerging economies.