15288 research outputs found
Sort by
Identification and Mitigation of Ferranti Effect on High Voltage Transmission Lines for Power Systems Reliability Improvement
Get PDFPower systems reliability is a function of transmission line performance.
External as well as internal factors influence the ability of transmission lines to
transport electrical energy as expected when demanded. External factors
such as weather-related events are well investigated and documented in
modern scientific and technological databases but same is not true for factors
which result from the intrinsic physical properties of conductors such as
Ferranti effect. The Ferranti effect is a phenomenon occurring in long
continuous transmission lines carrying high voltages whereby the receiving
end voltage is greater than the sending end voltage such that it could be
undesirably up to an amount that the survivability of the power system is
threatened, or further protection devices are required, or maintenance action
is needed. A holistic approach to power systems reliability means that
research effort must be devoted to fill identified critical gaps by extending
investigations to these neglected factors. This paper seeks to establish the
importance of Ferranti effect in the overarching reliability objective associated
with electrical energy dispatch from the point of generation to the point where
the energy is utilized by consumers, and it further proposes a mitigating
scheme that deploys the use of shunt reactors overvoltage suppression
devices
Identifying Key Reliability Factors in Micro- Grid Systems Using Principal Component Analysis.
Get PDFOne way to solve the shortage in power supply and the rapid load
growth is by operating power systems that could improve power supply
reliability. The study aims to carry out a holistic evaluation by identifying the
several reliability variables that could influence the micro-grid power system's
reliability which is vital in electricity generation. Thirty-three reliability
variable factors that are commonly observed to influence power systems
reliability were chosen for the micro-grid power systems study and examined
using the principal component analysis (PCA). The system reliability key
variables were evaluated using the StatistiXL software. A structured
questionnaire was crafted considering thirty-three reliability variables,
harvested from literature, and administered to respondents in the micro-grid
power system industry. The respondent size was determined at a level of
confidence of 95% and an error margin of 5% was deployed to corroborate an
adequate population size representation which validated the study data.
StatistiXL software was deployed to analyze the (mxn) data matrix, collated
from the respondents' scores. The matrix was used as the input variable for the
model deployed for the factor analysis. Nine factors with eigenvalues (λ>1)
were mined and labeled for the analysis, but all the trivial variables were
discarded. The PCA result holistically pinpointed the key reliability variables
that influence the micro-grid reliability, revealing that system availability
represented by factor 1 (F1) loaded 24% of the total variables studied, with
reliability cluster including Mean Time Between Failures (MTBF) = - 0.844,
Mean Time to Repair (MTTR) = - 0.737, Demand Response (DR) technique =
0.752, Failure Rate = 0.647 among others. The failure rate and the frequency of
outages in F1, were an indication that system availability would be influenced,
thereby affecting the micro-grid performance. The study also extracted some
weak factor loading, F8 and F9 indicting them as reliability variables whose influences do not impact negatively on the micro-grid reliability but should not
be discarded in the study of the reliability of micro-grid power systems. Hence
an attempt to improve the system's reliability, concentrating on the key
variables factors, the weak variables should not be neglected
A Comparative Performance Analysis of Task Scheduling Algorithms in Federated Clouds
Get PDFEfficient task scheduling is crucial in the domain of cloud computing. Cloud computing is a
service that allows users to access and share virtual resources as needed in order to fulfil
their jobs. The primary objective of task scheduling is to execute tasks in a manner that
maximizes performance by fully utilizing resources and minimising losses. Several
scheduling algorithms currently exist with the goal of achieving various objectives, including
minimising execution time, cost, makespan, enhancing resource utilisation, and load
balancing. This study evaluates and compares the performance of six scheduling
algorithms, including Particle Swarm Optimisation (PSO), Ant Colony Optimisation (ACO),
Q-Learning, Round Robin (RR), First-Come, First-Served (FCFS), and Shortest Job First
(SJF) algorithms. The algorithms' performance is assessed by comparing them using
standard measures, such as makespan, execution time, and throughput, across various
workload scenarios through graphical representation of the findings. The study employs
Java and CloudSim for the purpose of implementing and evaluating. The Particle Swarm
Optimisation (PSO) algorithm exhibits exceptional efficiency, particularly in minimising
makespan, obtaining optimal throughput, and attaining the shortest execution time. The
capacity to adjust to changing settings and efficiently utilise resources continually
demonstrates its worth in many situations. The study emphasizes the pivotal significance of
algorithm selection and data centre layout in optimising work scheduling, particularly in
dynamic and distributed cloud computing systems
Bolstering the Impact of Financial Inclusion on the Performance of Selected Deposit Money Banks in Nigeria
Get PDFThis study investigates the impact of financial inclusion on the financial
performance of deposit money banks in Nigeria. The problem statement arises from
the need to understand how various dimensions of financial inclusion, including
loans to customers, deposits, bank branches, mobile banking, and agency banking,
influence the returns on assets (ROA) of deposit money banks in Nigeria. Drawing
on theories of financial intermediation and inclusive growth, the research adopts a
quantitative approach, employing panel EGLS regression analysis to analyze data
collected from ten deposit money banks over an eleven-year period (2011-2022).
The findings reveal significant positive relationships between loans to customers,
deposits, bank branches, mobile banking, agency banking, and ROA, highlighting
the importance of financial inclusion in enhancing the performance of deposit
money banks. The study concludes that fostering financial inclusion through
targeted policies and initiatives can contribute to the resilience, stability, and
sustainability of the banking sector in Nigeria. The implications underscore the
importance of promoting inclusive financial systems to foster economic growth,
reduce poverty, and enhance social welfare. As a recommendation, policymakers
should prioritize measures aimed at expanding access to financial services,
leveraging technology, enhancing financial literacy, and strengthening regulatory
frameworks to facilitate greater financial inclusion and deepen the impact on the
broader economy
Control strategies in enhanced stand-alone mini-grid operations for the NESI–an overview
Get PDFDiverse control strategies for enhancing operations of isolated distribution grids
are reviewed. Such distribution grids are called mini-grids or micro-grids,
depending on their power flow capabilities. Robust control schemes identified
in other climates for mini-grid and micro-grid operations are yet to be fully
explored in the Nigerian electricity supply industry (NESI). Sustainable control
strategies suitable for isolated distribution grids in the NESI predicate on
capabilities for diverse objectives, such as energy conservation, affordability,
efficient power throughput, and utilization, for enhanced resiliency and
reliability. Consequently, the distributed control system in hierarchical layers is
identified as a suitable choice for mini-grid operations in Nigeria because of its
robustness in scalability and in energy conservation. However, the model
predictive control (MPC) scheme is observed to be uniquely applicable in all
of the hierarchical control layers. Therefore, a cascade-free MPC with improved
robustness against sensitivity to system parameter variation is presented at the
primary control layer for an H8 voltage source inverter (VSI) used for grid
integration of the solar photovoltaic (PV) system. The H8 inverter gives more
promising mitigation strategies against common-mode voltage and leakage
current. Moreover, the control of DC link voltage for maximum power point
tracking (MPPT) is achieved by the H8 inverter, thereby eliminating the need for a
separate converter for MPPT. Thus, sustainability is achieved
Multi‐instance Contingent Fusion for the Verification of Infant Fingerprints
Get PDFThere is a need to recognize newborns (1–28 days old) and infants (29 days–12 months old)
automatically, with the ubiquitous 500 ppi fingerprint reader, to combat newborn swapping, aid
identification of missing children, vaccination tracking, medical history, etc. This study seeks to show the
possibility of future identification of babies with fingerprints acquired with a 500 ppi fingerprint reader,
through multi‐instance (left thumb and right index fingers) fusion. The fingerprints were acquired from
babies who were 1 day–10 months old at enrolment (Session 1). The sum score fusion algorithm was
employed. This method produced verification accuracies of 73.8, 69.05, and 57.14% for time lapses of 1,
3, and 6 months, respectively, between enrolment and query fingerprints, for babies that were 0–3
months at the time of enrolment. To the best of our knowledge, this study is the first attempt to verify
infant fingerprints with multi‐instance contingent fusion. The incorporation of soft biometrics is
recommended for future studies
A machine learning-driven web application for sign language learning
Get PDFAddressing the increasing demand for accessible sign language learning tools,
this paper introduces an innovative Machine Learning-Driven Web Application
dedicated to Sign Language Learning. This web application represents a
significant advancement in sign language education. Unlike traditional
approaches, the application’s unique methodology involves assigning users
different words to spell. Users are tasked with signing each letter of the word,
earning a point upon correctly signing the entire word. The paper delves into
the development, features, and the machine learning framework underlying
the application. Developed using HTML, CSS, JavaScript, and Flask, the web
application seamlessly accesses the user’s webcam for a live video feed,
displaying the model’s predictions on-screen to facilitate interactive practice
sessions. The primary aim is to provide a learning platform for those who are
not familiar with sign language, offering them the opportunity to acquire this
essential skill and fostering inclusivity in the digital age
Progress in green hydrogen adoption in the African context
Get PDFHydrogen is an abundant element and a flexible energy carrier, offering
substantial potential as an environmentally friendly energy source to tackle
global energy issues. When used as a fuel, hydrogen generates only water
vapor upon combustion or in fuel cells, presenting a means to reduce carbon
emissions in various sectors, including transportation, industry, and power
generation. Nevertheless, conventional hydrogen production methods often
depend on fossil fuels, leading to carbon emissions unless integrated with
carbon capture and storage solutions. Conversely, green hydrogen is
generated through electrolysis powered by renewable energy sources like
solar and wind energy. This production method guarantees zero carbon
emissions throughout the hydrogen’s lifecycle, positioning it as a critical
component of global sustainable energy transitions. In Africa, where there are
extensive renewable energy resources such as solar and wind power, green
hydrogen is emerging as a viable solution to sustainably address the increasing
energy demands. This research explores the influence of policy frameworks,
technological innovations, and market forces in promoting green hydrogen
adoption across Africa. Despite growing investments and favorable policies,
challenges such as high production costs and inadequate infrastructure
significantly hinder widespread adoption. To overcome these challenges and
speed up the shift towards a sustainable hydrogen economy in Africa, strategic
investments and collaborative efforts are essential. By harnessing its renewable
energy potential and establishing strong policy frameworks, Africa can not only
fulfill its energy requirements but also support global initiatives to mitigate climate
change and achieve sustainable development objectives
Development of sustainable interlocking concrete paving blocks using bamboo leaf ash and metakaolin
Get PDFEco-friendly interlocking concrete pavement block was developed using the admixture of bamboo
leaf ash and metakaolin. This was done to develop an eco-friendly interlocking paving block for
sustainable pavement construction. Bamboo leaf ash and metakaolin were added as a supplementary
cementitious material. The supplementary cementitious material (bamboo leaf ash and
metakaolin) were admixed and added at 0, 5, 10, 15, 20, 25 and 30 % replacement of cement. The
workability of the fresh concrete (slump) at the varied percentage additions, and the mechanical
properties of the concrete at 7, 14, 28, and 56 days of curing were assessed, including their
microstructural characteristics. The outcome of the research showed that increasing the percentage
of (bamboo leaf ash + metakaolin) reduces the workability of the concrete. With a 20 %
addition of this cementitious material, the developed fresh concrete became unworkable. In
addition, replacing up to 10 % of the concrete in the pavement with bamboo leaf ash and metakaolin
increased the mechanical strength of the concrete by 28.7 %. At 30 % a percentage increase
of 3.6 % was recorded. However, the strength at 5 % was still adequate for pavement
construction with a 13.62 % increase in mechanical strength. The compressive strength at 5 %
and 10 % addition of the supplementary cementitious material at maturity met the criteria for
constructing a semi-rigid pavement, using IRC standards. The microstructural assessment showed
that the number of pores in the mature concrete samples decreased at 10 % addition of bamboo
leaf ash and metakaolin. The research data provides construction workers, researchers, and
highway engineers with vital information regarding the viability of these sustainable materials for
pavement improvement
A Study of Single Motherhood in Without Mercy, The Mirror of My Life, and Night Dancers.
Get PDFSingle motherhood is becoming ubiquitous today, unlike in the past, when it was almost
a sacrilege. This portends serious implications for society. This paper examines the tragic
conditions that a single mother and her child find themselves in while trying to navigate
the difficulties imposed on them by society. Three novels on the theme of single
motherhood were purposively selected from Nigeria; Abubakar's Without Mercy,
Asogwa's The Mirror of My Life, and Unigwe's Night Dancers. The study adopted the
content analytical method in interrogating the selected novels. A purposive sampling
technique was used to select three novels a total of twelve films comprising six
Nollywood and six Hollywood films. The novels were subjected to content and
qualitative analysis to explore the issues of single motherhood. The study adopted
Attachment Theory as the framework for analysis. Findings revealed that children raised
by both parents exhibit a wholesome attitude towards life and suffer little or no rejection
from people. Whereas, a child brought up by a single parent faces social rejection, and
psychological depression, and becomes behaviorally dysfunctional. Every inherent
character defect or otherwise displayed by a child raised by a single mother is a factor of
societal attitude towards the peculiar challenge of the parent. Moreover, the tragic
conditions experienced by single mothers/their children are compounded by
stigmatisation, psychological pressure, victimisation, rejection, taunting, and mockery.
The paper recommends that the society should reappraise its value system by accepting
single motherhood as a socio-reality to save the society from violence and suicide.
Keywords: Attachment theory, contemporary Nigerian novels, parenthood, single
motherhood, sensitive parenting