Abstract: Thermoacoustic refrigerator is a cooling device which
uses the acoustic waves to produce the cooling effect. The aim of this
paper is to explore the experimental and numerical feasibility of a
standing-wave thermoacoustic refrigerator. The effects of the stack
length, position of stack and operating frequency on the cooling
performance are carried out. The circular pore stacks are tested under
the atmospheric pressure. A low-cost loudspeaker is used as an
acoustic driver. The results show that the location of stack installed in
resonator tube has a greater effect on the cooling performance, than
the stack length and operating frequency, respectively. The
temperature difference across the ends of stack can be generated up
to 13.7°C, and the temperature of cold-end is dropped down by 5.3°C
from the ambient temperature.
Abstract: Project Portfolio Management (PPM) is an essential
component of an organisation’s strategic procedures, which requires
attention of several factors to envisage a range of long-term outcomes
to support strategic project portfolio decisions. To evaluate overall
efficiency at the portfolio level, it is essential to identify the
functionality of specific projects as well as to aggregate those
findings in a mathematically meaningful manner that indicates the
strategic significance of the associated projects at a number of levels
of abstraction. PPM success is directly associated with the quality of
decisions made and poor judgment increases portfolio costs. Hence,
various Multi-Criteria Decision Making (MCDM) techniques have
been designed and employed to support the decision-making
functions. This paper reviews possible options to enhance the
decision-making outcomes in organisational portfolio management
processes using the Analytic Hierarchy Process (AHP) both from
academic and practical perspectives and will examine the usability,
certainty and quality of the technique. The results of the study will
also provide insight into the technical risk associated with current
decision-making model to underpin initiative tracking and strategic
portfolio management.
Abstract: A seizure prediction method is proposed by extracting
global features using phase correlation between adjacent epochs for
detecting relative changes and local features using fluctuation/
deviation within an epoch for determining fine changes of different
EEG signals. A classifier and a regularization technique are applied
for the reduction of false alarms and improvement of the overall
prediction accuracy. The experiments show that the proposed method
outperforms the state-of-the-art methods and provides high prediction
accuracy (i.e., 97.70%) with low false alarm using EEG signals in
different brain locations from a benchmark data set.
Abstract: The power electronic components within Electric Vehicles (EV) need to operate in several important modes. Some modes directly influence safety, while others influence vehicle performance. Given the variety of functions and operational modes required of the power electronics, it needs to meet efficiency requirements to minimize power losses. Another challenge in the control and construction of such systems is the ability to support bidirectional power flow. This paper considers the construction, operation, and feasibility of available converters for electric vehicles with feasible configurations of electrical buses and loads. This paper describes logic and control signals for the converters for different operations conditions based on the efficiency and energy usage bases.
Abstract: The transesterification of dimethyl malonate (DMM)
with phenol has been studied in vapour phase over cordierite
honeycomb coated with solid acid catalysts such as ZrO2,
Mo(VI)/ZrO2 and SO42-/ZrO2. The catalytic materials were prepared
honeycomb coated, powder forms, and characterized for their total
surface acidity by NH3-TPD and crystalinity by powder XRD
methods. Phenyl methyl malonate (PMM) and diphenyl malonate
(DPM) were obtained as the reaction products. A good conversion of
DMM (up to 82%) of MPM with 95% selectivity was observed when
the reactions were carried out at a catalyst bed temperature of 200 °C
and flow-rate of 10 mL/h in presence of Mo(VI)/ZrO2 as catalyst.
However, over SO4^2-/ZrO2 catalyst, the yield of DPM was found to be
higher. The results have been interpreted based on the variation of
acidic properties and powder XRD phases of zirconia on
incorporation of Mo(VI) or SO42– ions. Transesterification reactions
were also carried out over powder forms of the catalytic materials
and the yield of the desired phenyl ester products were compared
with that of the HC coated catalytic materials. The solid acids were
found to be reusable when used for at least 5 reaction cycles.
Abstract: Considering the challenges of short product life cycles
and growing variant diversity, cost minimization and manufacturing
flexibility increasingly gain importance to maintain a competitive
edge in today’s global and dynamic markets. In this context, an
aerodynamic part feeding system for high-speed industrial assembly
applications has been developed at the Institute of Production
Systems and Logistics (IFA), Leibniz Universitaet Hannover. The
aerodynamic part feeding system outperforms conventional systems
with respect to its process safety, reliability, and operating speed. In
this paper, a multi-objective optimisation of the aerodynamic feeding
system regarding the orientation rate, the feeding velocity, and the
required nozzle pressure is presented.
Abstract: In this paper, a robust fault detection and isolation
(FDI) scheme is developed to monitor a multivariable nonlinear
chemical process called the Chylla-Haase polymerization reactor,
when it is under the cascade PI control. The scheme employs a radial
basis function neural network (RBFNN) in an independent mode to
model the process dynamics, and using the weighted sum-squared
prediction error as the residual. The Recursive Orthogonal Least
Squares algorithm (ROLS) is employed to train the model to
overcome the training difficulty of the independent mode of the
network. Then, another RBFNN is used as a fault classifier to isolate
faults from different features involved in the residual vector. Several
actuator and sensor faults are simulated in a nonlinear simulation of
the reactor in Simulink. The scheme is used to detect and isolate the
faults on-line. The simulation results show the effectiveness of the
scheme even the process is subjected to disturbances and
uncertainties including significant changes in the monomer feed rate,
fouling factor, impurity factor, ambient temperature, and
measurement noise. The simulation results are presented to illustrate
the effectiveness and robustness of the proposed method.
Abstract: Durian skin is a newly explores natural fibre
potentially reinforced polyolefin for diverse applications. In this
work, investigation on the effect of coupling agent, maleic anhydride
polypropylene (MAPP) on the mechanical, morphological, and
thermal properties of polypropylene (PP) reinforced with durian skin
fibre (DSF) was conducted. The presence of 30 wt% DSF
significantly reduced the tensile strength of PP-DSF composite.
Interestingly, even though the same trend goes to PP-DSF with the
presence of MAPP, the reduction is only about 4% relative to
unreinforced PP and 18% higher than PP-DSF without MAPP
(untreated composite or UTC). The used of MAPP in treated
composite (TC) also increased the tensile modulus, flexural
properties and degradation temperature. The enhanced mechanical
properties are consistent with good interfacial interaction as
evidenced under scanning electron microscopy.
Abstract: Much of the literature on research design has focused
on research conducted in developed, uni-cultural or primarily English
speaking countries. Studies of qualitative case study research, the
challenges, and prospects have been embedded in Western/Eurocentric
society and social theories. Although there have been some
theoretical studies, few empirical studies have been conducted to
explore the nature of the challenges of qualitative case study in
developing countries. These challenges include accessibility to
organizations, conducting interviews in developing countries,
accessing documents and observing official meetings, language and
cultural challenges, the use of consent forms, issues affecting access
to companies, respondent issues, and data analysis. The author, while
conducting qualitative case study research in Libya, faced all these
issues. The discussion in this paper examines these issues in order to
make a contribution toward the literature in this area.
Abstract: A model to predict the plastic zone size for material
under plane stress condition has been developed and verified
experimentally. The developed model is a function of crack size,
crack angle and material property (dislocation density). Simulation
and validation results show that the model developed show good
agreement with experimental results. Samples of low carbon steel
(0.035%C) with included surface crack angles of 45o, 50o, 60o, 70o
and 90o and crack depths of 2mm and 4mm were subjected to low
strain rate between 0.48 x 10-3 s-1 – 2.38 x 10-3 s-1. The mechanical
properties studied were ductility, tensile strength, modulus of
elasticity, yield strength, yield strain, stress at fracture and fracture
toughness. The experimental study shows that strain rate has no
appreciable effect on the size of plastic zone while crack depth and
crack angle plays an imperative role in determining the size of the
plastic zone of mild steel materials.
Abstract: The goal of this paper is to identify the main
differences in the way men and women perceive TV ads. This paper
is based on a research project conducted partly as a review of relevant
papers, which deals with gender influence on the cognitive process
and postmodern perception of advertising. In addition to that,
qualitative research was conducted by means of interviews and
structured questionnaires. Furthermore, data acquired from the
research were used to evaluate our objectives and hypotheses. The
goal of this paper is to compare women's and men's perception of
advertisement. Although women are able to perceive more details
than men, men are more susceptible to sexual appeals in advertising.
Significant differences were also found in the perception of sexual
appeals in the context of gender.
Abstract: We have studied the temporal characteristics of
bistable perception of the stimuli of two types: one involves
alterations in a perceived depth and another one has an ambiguous
content. We used the Necker lattice and lines of shadowed circles
ambiguously perceived either as spheres or holes as stimuli of the
first type. The Winson figure (the Eskimo/Indian picture) was a
stimulus of the second type. We have analyzed how often the
reversals occurred (reversal rate) and for how long each of the two
interpretations, or percepts, was observed during one presentation
(stability durations). For all three ambiguous images the reversal rate
and the stability durations had similar values, which provide another
evidence for a significant role of top-down processes in multistable
perception.
Abstract: Concurrent planning of project scheduling and
material ordering has been increasingly addressed within last decades
as an approach to improve the project execution costs. Therefore, we
have taken the problem into consideration in this paper, aiming to
maximize schedules quality robustness, in addition to minimize the
relevant costs. In this regard, a bi-objective mathematical model is
developed to formulate the problem. Moreover, it is possible to
utilize the all-unit discount for materials purchasing. The problem is
then solved by the E-constraint method, and the Pareto front is
obtained for a variety of robustness values. The applicability and
efficiency of the proposed model is tested by different numerical
instances, finally.
Abstract: Political participation involves voluntary and
deliberate efforts by the members of a political system to determine
the kinds of political institution and individuals that will govern them
and equally influence the mobilization and allocation of the available
societal resources. Over the years, youths in Nigeria participate
actively in political party rallies and voting to elect their leaders and
representatives in governance. This paper examines categories and
nature of participation in politics as well as factors that drive youths
into politics in Sokoto State. A survey conducted, through focus
group discussions, interviews and questionnaire, in the six sampled
Local Government of Sokoto State identifies three category of
political participation; namely, active, moderate and apathetic
participation. The findings reveal that 63.57% of respondents are
apathetic to politics in the State and unemployed youth constitutes
34.74% of the entire responses. The paper establishes that lack of
attainment of need (63.22%) is one of the reasons that make youths
engage into participatory activities that encourage political thuggery
and manipulation of electoral outcomes. The paper recommends that
youths should be engaged into positive rational participatory
activities that ensure inclusiveness and promotion of good
governance in Nigeria. It is hoped that this will enlighten youths and
policy implementers on the constructive strategies in controlling
youths’ negative participation in politics in Nigeria.
Abstract: Selenium is an-antioxidant which is important for
human health enters food chain through crops. In Kenya Zea mays is
consumed by 96% of population hence is a cheap and convenient
method to provide selenium to large number of population. Several
soil factors are known to have antagonistic effects on selenium
speciation hence the uptake by Zea mays. There are no studies in
Kenya that has been done to determine the effects of soil
characteristics (pH, Tcarbon, CEC, Eh) affect accumulation of
selenium in Zea mays grains in Maize Belt in Kenya. About 100 Zea mays grain samples together with 100 soil samples
were collected from the study site put in separate labeled Ziplocs and
were transported to laboratories at room temperature for analysis.
Maize grains were analyzed for selenium while soil samples were
analyzed for pH, Cat Ion Exchange Capacity, total carbon, and
electrical conductivity. The mean selenium in Zea mays grains varied from 1.82 ± 0.76
mg/Kg to 11±0.86 mg/Kg. There was no significant difference
between selenium levels between different grain batches {χ (Df =76)
= 26.04 P= 1.00} The pH levels varied from 5.43± 0.58 to 5.85±
0.32. No significant correlations between selenium in grains and soil
pH (Pearson’s correlations = - 0.143), and between selenium levels in
grains and the four (pH, Tcarbon, CEC, Eh) soil chemical
characteristics {F (4,91) = 0.721 p = 0.579} was observed. It can be concluded that the soil chemical characteristics in the
study site did not significantly affect the accumulation of native
selenium in Zea mays grains.
Abstract: The modelling of physical phenomena, such as the
earth’s free oscillations, the vibration of strings, the interaction of
atomic particles, or the steady state flow in a bar give rise to Sturm-
Liouville (SL) eigenvalue problems. The boundary applications of
some systems like the convection-diffusion equation, electromagnetic
and heat transfer problems requires the combination of Dirichlet and
Neumann boundary conditions. Hence, the incorporation of Robin
boundary condition in the analyses of Sturm-Liouville problem. This
paper deals with the computation of the eigenvalues and
eigenfunction of generalized Sturm-Liouville problems with Robin
boundary condition using the finite element method. Numerical
solution of classical Sturm–Liouville problem is presented. The
results show an agreement with the exact solution. High results
precision is achieved with higher number of elements.
Abstract: Global economy today is full of sophistication. All
over the world, business and marketing practices are undergoing
unprecedented transformation. In realization of this fact, the federal
government of Nigeria has put in place a robust transformation
agenda in order to put Nigeria in a better position to be a competitive
player and in the process transform all sectors of its economy. New
technologies, especially the Internet, are the driving force behind this
transformation. However, technology has inadvertently affected the
way businesses are done thus necessitating the acquisition of new
skills. In developing countries like Nigeria, citizens are still battling
with effective application of those technologies. Obviously, students
of business education need to acquire relevant business knowledge to
be able to transit into the world of work on graduation from school
and compete favorably in the labor market. Therefore, effective
utilization of social media by both teachers and students can help
extensively in empowering students with the needed skills. Social
media which is a group of Internet-based applications built on the
ideological foundations of Web 2.0, that allow the creation and
exchange of user generated content, and if incorporated into the
classroom experience may be the needed answer to unemployment
and poverty in Nigeria as beneficiaries can easily connect with
existing and potential enterprises and customers, engage with them
and reinforce mutual business benefits. Challenges and benefits of
social media use in education in Nigeria universities were revealed in
this study.
Abstract: This research work presents the surface
thermodynamics approach to M-TB/HIV-Human sputum
interactions. This involved the use of the Hamaker coefficient
concept as a surface energetics tool in determining the interaction
processes, with the surface interfacial energies explained using van
der Waals concept of particle interactions. The Lifshitz derivation for
van der Waals forces was applied as an alternative to the contact
angle approach which has been widely used in other biological
systems. The methodology involved taking sputum samples from
twenty infected persons and from twenty uninfected persons for
absorbance measurement using a digital Ultraviolet visible
Spectrophotometer. The variables required for the computations with
the Lifshitz formula were derived from the absorbance data. The
Matlab software tools were used in the mathematical analysis of the
data produced from the experiments (absorbance values). The
Hamaker constants and the combined Hamaker coefficients were
obtained using the values of the dielectric constant together with the
Lifshitz Equation. The absolute combined Hamaker coefficients
A132abs and A131abs on both infected and uninfected sputum samples
gave the values of A132abs = 0.21631x10-21Joule for M-TB infected
sputum and Ã132abs = 0.18825x10-21Joule for M-TB/HIV infected
sputum. The significance of this result is the positive value of the
absolute combined Hamaker coefficient which suggests the existence
of net positive van der waals forces demonstrating an attraction
between the bacteria and the macrophage. This however, implies that
infection can occur. It was also shown that in the presence of HIV,
the interaction energy is reduced by 13% conforming adverse effects
observed in HIV patients suffering from tuberculosis.
Abstract: This study aims to examine the sensory quality of
meatballs made from Balinese beef and buffalo meat after the
addition of smoke powder prior to storage at the temperatures of 2-
5°C for 7 days. This study used meat from Longissimus dorsi muscle
of male Balinese cattle aged 3 years and of male buffalo aged 5 years
as the main raw materials, and smoke powder as a binder and
preservative in making meatballs. The study was based on completely
randomized design (CRD) of factorial pattern of 2 x 3 x 2 where
factors 1, 2 and 3 included the types of meat (cattle and buffalo),
types of smoke powder (oven dried, freeze dried and spray dried)
with a level of 2% of the weight of the meat (w/w), and storage
duration (0 and 7 days) with three replications, respectively. The
parameters measured were the meatball sensory quality (scores of
tenderness, firmness, chewing residue, and intensity of flavor). The
results of this study show that each type of meat has produced
different sensory characteristics. The meatballs made from buffalo
meat have higher tenderness and elasticity scores than the Balinese
beef. Meanwhile, the buffalo meatballs have a lower residue
mastication score than the Balinese beef. Each type of smoke
powders has produced a relatively similar sensory quality of
meatballs. It can be concluded that the smoke powder of 2% of the
weight of the meat (w/w) could maintain the sensory quality of the
meatballs for 7 days of storage.
Abstract: The aim of this study is to evaluate the effect of
supplementing broiler starter diet with different levels of an essential
oil blend (EOB) containing capsaicin, carvacrol and cinnamaldehyde
on the performance of broilers. A total of 300 day-old straight-run
Cobb broiler chicks were randomly assigned to three treatments after
7-day group brooding following a completely randomized design
(CRD). Birds assigned in treatment 1 were given starter basal diet
while those in treatments 2 and 3 were given starter basal diet with
400 mg/kg antibiotic growth promoter (AGP) and 150 mg/kg EOB,
respectively, until the 28th day. Basal finisher feed were given for all
the treatments until harvest. Following 37 d feeding, body weight
gain, feed consumption, feed efficiency, dressing percentage,
livability and jejunal villi height were determined. Results showed no
significant differences (P>0.05) in growth performance. However,
villi height and crypt depth was significantly lower for birds fed
EOB.