Abstract: This paper presents a means for reducing the torque
variation during the revolution of a vertical-axis water turbine
(VAWaterT) by increasing the blade number. For this purpose, twodimensional
CFD analyses have been performed on a straight-bladed
Darrieus-type rotor. After describing the computational model and
the relative validation procedure, a complete campaign of
simulations, based on full RANS unsteady calculations, is proposed
for a three, four and five-bladed rotor architectures, characterized by
a NACA 0025 airfoil. For each proposed rotor configuration, flow
field characteristics are investigated at several values of tip speed
ratio, allowing a quantification of the influence of blade number on
flow geometric features and dynamic quantities, such as rotor torque
and power. Finally, torque and power curves are compared for the
three analyzed architectures, achieving a quantification of the effect
of blade number on overall rotor performance.
Abstract: This paper demonstrates the application of craziness based particle swarm optimization (CRPSO) technique for designing the 8th order low pass Infinite Impulse Response (IIR) filter. CRPSO, the much improved version of PSO, is a population based global heuristic search algorithm which finds near optimal solution in terms of a set of filter coefficients. Effectiveness of this algorithm is justified with a comparative study of some well established algorithms, namely, real coded genetic algorithm (RGA) and particle swarm optimization (PSO). Simulation results affirm that the proposed algorithm CRPSO, outperforms over its counterparts not only in terms of quality output i.e. sharpness at cut-off, pass band ripple, stop band ripple, and stop band attenuation but also in convergence speed with assured stability.
Abstract: By means of the extended homoclinic test approach (shortly EHTA) with the aid of a symbolic computation system such as Maple, some complexiton type solutions for the (3+1)-dimensional Jimbo-Miwa equation are presented.
Abstract: We present a new intuitionistic fuzzy aggregation
operator called the intuitionistic fuzzy ordered weighted
averaging-weighted average (IFOWAWA) operator. The main
advantage of the IFOWAWA operator is that it unifies the OWA
operator with the WA in the same formulation considering the degree
of importance that each concept has in the aggregation. Moreover, it is
able to deal with an uncertain environment that can be assessed with
intuitionistic fuzzy numbers. We study some of its main properties and
we see that it has a lot of particular cases such as the intuitionistic
fuzzy weighted average (IFWA) and the intuitionistic fuzzy OWA
(IFOWA) operator. Finally, we study the applicability of the new
approach on a financial decision making problem concerning the
selection of financial strategies.
Abstract: The precision of heat flux simulation influences the
temperature field and test aberration for TB test and also reflects the
test level for spacecraft development. This paper describes TB tests for
a small satellite using solar simulator, electric heaters, calrod heaters
to evaluate the difference of the three methods. Under the same
boundary condition, calrod heaters cases were about 6oC higher than
solar simulator cases and electric heaters cases for
non-external-heat-flux cases (extreme low temperature cases). While
calrod heaters cases and electric heaters cases were 5~7oC and 2~3oC
lower than solar simulator cases respectively for high temperature
cases. The results show that the solar simulator is better than calrod
heaters for its better collimation, non-homogeneity and stability.
Abstract: Following the loss of NASA's Space Shuttle
Columbia in 2003, it was determined that problems in the agency's
organization created an environment that led to the accident. One
component of the proposed solution resulted in the formation of the
NASA Engineering Network (NEN), a suite of information retrieval
and knowledge-sharing tools. This paper describes the
implementation of communities of practice, which are formed along
engineering disciplines. Communities of practice enable engineers to
leverage their knowledge and best practices to collaborate and take
information learning back to their jobs and embed it into the
procedures of the agency. This case study offers insight into using
traditional engineering disciplines for virtual collaboration, including
lessons learned during the creation and establishment of NASA-s
communities.
Abstract: Current image-based individual human recognition
methods, such as fingerprints, face, or iris biometric modalities
generally require a cooperative subject, views from certain aspects,
and physical contact or close proximity. These methods cannot
reliably recognize non-cooperating individuals at a distance in the
real world under changing environmental conditions. Gait, which
concerns recognizing individuals by the way they walk, is a relatively
new biometric without these disadvantages. The inherent gait
characteristic of an individual makes it irreplaceable and useful in
visual surveillance.
In this paper, an efficient gait recognition system for human
identification by extracting two features namely width vector of
the binary silhouette and the MPEG-7-based region-based shape
descriptors is proposed. In the proposed method, foreground objects
i.e., human and other moving objects are extracted by estimating
background information by a Gaussian Mixture Model (GMM) and
subsequently, median filtering operation is performed for removing
noises in the background subtracted image. A moving target classification
algorithm is used to separate human being (i.e., pedestrian)
from other foreground objects (viz., vehicles). Shape and boundary
information is used in the moving target classification algorithm.
Subsequently, width vector of the outer contour of binary silhouette
and the MPEG-7 Angular Radial Transform coefficients are taken as
the feature vector. Next, the Principal Component Analysis (PCA)
is applied to the selected feature vector to reduce its dimensionality.
These extracted feature vectors are used to train an Hidden Markov
Model (HMM) for identification of some individuals. The proposed
system is evaluated using some gait sequences and the experimental
results show the efficacy of the proposed algorithm.
Abstract: To evaluate the ability to predict xerostomia after
radiotherapy, we constructed and compared neural network and
logistic regression models. In this study, 61 patients who completed a
questionnaire about their quality of life (QoL) before and after a full
course of radiation therapy were included. Based on this questionnaire,
some statistical data about the condition of the patients’ salivary
glands were obtained, and these subjects were included as the inputs of
the neural network and logistic regression models in order to predict
the probability of xerostomia. Seven variables were then selected from
the statistical data according to Cramer’s V and point-biserial
correlation values and were trained by each model to obtain the
respective outputs which were 0.88 and 0.89 for AUC, 9.20 and 7.65
for SSE, and 13.7% and 19.0% for MAPE, respectively. These
parameters demonstrate that both neural network and logistic
regression methods are effective for predicting conditions of parotid
glands.
Abstract: In this paper, Tobephobia (TBP) alludes to the fear of
failure experienced by teachers to manage curriculum change. TBP is
an emerging concept and it extends the boundaries of research in
terms of how we view achievement and failure in education.
Outcomes-based education (OBE) was introduced fifteen years ago
in South African schools without simultaneously upgrading teachers-
professional competencies. This exploratory research, therefore
examines a simple question: What is the impact of TBP and OBE on
teachers? Teacher ineptitude to cope with the OBE curriculum in the
classroom is a serious problem affecting large numbers of South
African teachers. This exploratory study sought to determine the
perceived negative impact of OBE and TBP on teachers. A survey
was conducted amongst 311 teachers in Port Elizabeth and Durban,
South Africa. The results confirm the very negative impact of TBP
and OBE on teachers. This exploratory study authenticates the
existence of TBP.
Abstract: This study demonstrates the use of Class F fly ash in
combination with lime or lime kiln dust in the full depth reclamation
(FDR) of asphalt pavements. FDR, in the context of this paper, is a
process of pulverizing a predetermined amount of flexible pavement
that is structurally deficient, blending it with chemical additives and
water, and compacting it in place to construct a new stabilized base
course. Test sections of two structurally deficient asphalt pavements
were reclaimed using Class F fly ash in combination with lime and
lime kiln dust. In addition, control sections were constructed using
cement, cement and emulsion, lime kiln dust and emulsion, and mill
and fill. The service performance and structural behavior of the FDR
pavement test sections were monitored to determine how the fly ash
sections compared to other more traditional pavement rehabilitation
techniques. Service performance and structural behavior were
determined with the use of sensors embedded in the road and Falling
Weight Deflectometer (FWD) tests. Monitoring results of the FWD
tests conducted up to 2 years after reclamation show that the cement,
fly ash+LKD, and fly ash+lime sections exhibited two year resilient
modulus values comparable to open graded cement stabilized
aggregates (more than 750 ksi). The cement treatment resulted in a
significant increase in resilient modulus within 3 weeks of
construction and beyond this curing time, the stiffness increase was
slow. On the other hand, the fly ash+LKD and fly ash+lime test
sections indicated slower shorter-term increase in stiffness. The fly
ash+LKD and fly ash+lime section average resilient modulus values
at two years after construction were in excess of 800 ksi. Additional
longer-term testing data will be available from ongoing pavement
performance and environmental condition data collection at the two
pavement sites.
Abstract: Freeways are originally designed to provide high
mobility to road users. However, the increase in population and
vehicle numbers has led to increasing congestions around the world.
Daily recurrent congestion substantially reduces the freeway capacity
when it is most needed. Building new highways and expanding the
existing ones is an expensive solution and impractical in many
situations. Intelligent and vision-based techniques can, however, be
efficient tools in monitoring highways and increasing the capacity of
the existing infrastructures. The crucial step for highway monitoring
is vehicle detection. In this paper, we propose one of such
techniques. The approach is based on artificial neural networks
(ANN) for vehicles detection and counting. The detection process
uses the freeway video images and starts by automatically extracting
the image background from the successive video frames. Once the
background is identified, subsequent frames are used to detect
moving objects through image subtraction. The result is segmented
using Sobel operator for edge detection. The ANN is, then, used in
the detection and counting phase. Applying this technique to the
busiest freeway in Riyadh (King Fahd Road) achieved higher than
98% detection accuracy despite the light intensity changes, the
occlusion situations, and shadows.
Abstract: Experimental data are presented to show the influence of different types of chemical demulsifier on the stability and demulsification of emulsions. Three groups of demulsifier with different functional groups were used in this work namely amines, alcohol and polyhydric alcohol. The results obtained in this study have exposed the capability of chemical breaking agents in destabilization of water in crude oil emulsions. From the present study, found that molecular weight of the demulsifier were influent the capability of the emulsion to separate.
Abstract: Waste corn pulp was investigated as a potential feedstock during vermicomposting using Eisenia fetida. Corn pulp is the major staple food in Southern Africa and constitutes about 25% of the total organic waste. Wastecooked corn pulp was blended with cow dung in the ratio 6:1 respectively to optimize the vermicomposting process. The feedstock was allowed to vermicompost for 30 days. The vermicomposting took place in a 3- tray plastic worm bin. Moisture content, temperature, pH, and electrical conductivity were monitoreddaily. The NPK content was determined at day 30. During vermicomposting, moisture content increased from 27.68% to 52.41%, temperature ranged between 19- 25◦C, pH increased from 5.5 to 7.7, and electrical conductivity decreased from 80000μS/cm to 60000μS/cm. The ash content increased from 11.40% to 28.15%; additionally the volatile matter increased from 1.45% to 10.02%. An odorless, dark brown vermicompost was obtained. The vermicompost NPK content was 4.19%, 1.15%, and 6.18% respectively.
Abstract: Fructooligosaccharides derived from microbial enzyme especially from fungal sources has been received particular attention due to its beneficial effects as prebiotics and mass production. However, fungal fermentation is always cumbersome due to its broth rheology problem that will eventually affect the production of FOS. This study investigated the efficiency of immobilized cell system using rotating fibrous bed bioreactor (RFBB) in producing fructooligosaccharides (FOS). A comparative picture with respect to conventional stirred tank bioreactor (CSTB) and RFBB has been presented. To demonstrate the effect of agitation intensity and aeration rate, a laboratory-scale bioreactor 2.5 L was operated in three phases (high, medium, low) for 48 hours. Agitation speed has a great influence on P. simplicissimum fermentation for FOS production, where the volumetric FOS productivity using RFBB is increased with almost 4 fold compared to the FOS productivity in CSTB that only 0.319 g/L/h. Rate of FOS production increased up to 1.2 fold when immobilized cells system was employed at aeration rate similar to the freely suspended cells at 2.0 vvm.
Abstract: Rice, which is the staple food in Sierra Leone, is
consumed on a daily basis. It is the most imperative food crop
extensively grown by farmers across all ecologies in the country.
Though much attention is now given to rice grain production through
the small holder commercialization programme (SHCP), however, no
attention has been given in investigating the limitations faced by rice
producers. This paper will contribute to attempts to overcome the
development challenges caused by food insecurity. The objective of
this paper is thus, to analysis the relationship between rice production
and the domestic retail price of rice. The study employed a log linear
model in which, the quantity of rice produced is the dependent
variable, quantity of rice imported, price of imported rice and price of
domestic rice as explanatory variables. Findings showed that, locally
produced rice is even more expensive than the imported rice per ton,
and almost all the inhabitants in the capital city which hosts about
65% of the entire population of the country favor imported rice, as it
is free from stones with other impurities. On the other hand, to
control price and simultaneously increase rice production, the
government should purchase the rice from the farmers and then sell to private retailers.
Abstract: Cancers could normally be marked by a number of
differentially expressed genes which show enormous potential as
biomarkers for a certain disease. Recent years, cancer classification
based on the investigation of gene expression profiles derived by
high-throughput microarrays has widely been used. The selection of
discriminative genes is, therefore, an essential preprocess step in
carcinogenesis studies. In this paper, we have proposed a novel gene
selector using information-theoretic measures for biological
discovery. This multivariate filter is a four-stage framework through
the analyses of feature relevance, feature interdependence, feature
redundancy-dependence and subset rankings, and having been
examined on the colon cancer data set. Our experimental result show
that the proposed method outperformed other information theorem
based filters in all aspect of classification errors and classification
performance.
Abstract: The interaction of the blade tip with the casing
boundary layer and the leakage flow may lead to a kind of cavitation
namely tip vortex cavitation. In this study, the onset of tip vortex
cavitation was experimentally investigated in an axial flow pump.
For a constant speed and a fixed angle of attack and by changing the
flow rate, the pump head, input power, output power and efficiency
were calculated and the pump characteristic curves were obtained.
The cavitation phenomenon was observed with a camera and a
stroboscope. Finally, the critical flow region, which tip vortex
cavitation might have occurred, was identified. The results show that
just by adjusting the flow rate, out of the specified region, the
possibility of occurring tip vortex cavitation, decreases to a great
extent.
Abstract: The common bean is the most important grain legume for direct human consumption in the world and BCMV is one of the world's most serious bean diseases that can reduce yield and quality of harvested product. To determine the best tolerance index to BCMV and recognize tolerant genotypes, 2 experiments were conducted in field conditions. Twenty five common bean genotypes were sown in 2 separate RCB design with 3 replications under contamination and non-contamination conditions. On the basis of the results of indices correlations GMP, MP and HARM were determined as the most suitable tolerance indices. The results of principle components analysis indicated 2 first components totally explained 98.52% of variations among data. The first and second components were named potential yield and stress susceptible respectively. Based on the results of BCMV tolerance indices assessment and biplot analysis WA8563-4, WA8563-2 and Cardinal were the genotypes that exhibited potential seed yield under contamination and noncontamination conditions.
Abstract: The number of framework conceived for e-learning
constantly increase, unfortunately the creators of learning materials
and educational institutions engaged in e-formation adopt a
“proprietor" approach, where the developed products (courses,
activities, exercises, etc.) can be exploited only in the framework
where they were conceived, their uses in the other learning
environments requires a greedy adaptation in terms of time and
effort. Each one proposes courses whose organization, contents,
modes of interaction and presentations are unique for all learners,
unfortunately the latter are heterogeneous and are not interested by
the same information, but only by services or documents adapted to
their needs. Currently the new tendency for the framework
conceived for e-learning, is the interoperability of learning materials,
several standards exist (DCMI (Dublin Core Metadata Initiative)[2],
LOM (Learning Objects Meta data)[1], SCORM (Shareable Content
Object Reference Model)[6][7][8], ARIADNE (Alliance of Remote
Instructional Authoring and Distribution Networks for Europe)[9],
CANCORE (Canadian Core Learning Resource Metadata
Application Profiles)[3]), they converge all to the idea of learning
objects. They are also interested in the adaptation of the learning
materials according to the learners- profile. This article proposes an
approach for the composition of courses adapted to the various
profiles (knowledge, preferences, objectives) of learners, based on
two ontologies (domain to teach and educational) and the learning
objects.
Abstract: Pakistani doctors (MBBS) are emigrating towards developed countries for professional adjustments. This study aims to highlight causes and consequences of doctors- brain drain from Pakistan. Primary data was collected from Mayo Hospital, Lahore by interviewing doctors (n=100) through systematic random sampling technique. It found that various socio-economic and political conditions are working as push and pull factors for brain drain of doctors in Pakistan. Majority of doctors (83%) declared poor remunerations and professional infrastructure of health department as push factor of doctors- brain drain. 81% claimed that continuous instability in political situation and threats of terrorism are responsible for emigration of doctors. 84% respondents considered fewer opportunities of further studies responsible for their emigration. Brain drain of doctors is affecting health sector-s policies / programs, standard doctor-patient ratios and quality of health services badly.