Abstract: Brushless DC motors (BLDC) are widely used in
industrial areas. The BLDC motors are driven either by indirect ACAC
converters or by direct AC-AC converters. Direct AC-AC
converters i.e. matrix converters are used in this paper to drive the
three phase BLDC motor and it eliminates the bulky DC link energy
storage element. A matrix converter converts the AC power supply to
an AC voltage of variable amplitude and variable frequency. A
control technique is designed to generate the switching pulses for the
three phase matrix converter. For the control of speed of the BLDC
motor a separate PI controller and Fuzzy Logic Controller (FLC) are
designed and a hysteresis current controller is also designed for the
control of motor torque. The control schemes are designed and tested
separately. The simulation results of both the schemes are compared
and contrasted in this paper. The results show that the fuzzy logic
control scheme outperforms the PI control scheme in terms of
dynamic performance of the BLDC motor. Simulation results are
validated with the experimental results.
Abstract: The purposes of this study were to: 1) investigate
operation conditions of SME automotive part industry in Bangkok
and vicinity and 2) to compare operation problem levels of SME
automotive part industry in Bangkok and vicinity according to the
sizes of the enterprises. Samples in this study included 196
entrepreneurs of SME automotive part industry in Bangkok and
vicinity derived from simple random sampling and calculation from
R. V. Krejcie and D. W. Morgan’s tables. Research statistics included
frequency, percentage, mean, standard deviation, and T-test. The
results revealed that in general the problem levels of SME automotive
part industry in Bangkok and vicinity were high. When considering
in details, it was found that the problem levels were high at every
aspect, i.e. personal, production, export, finance, and marketing
respectively. The comparison of the problem levels according to the
sizes of the enterprises revealed statistically significant differences at
.05. When considering on each aspect, it was found that the aspect
with the statistical difference at .05 included 5 aspects, i.e.
production, marketing, finance, personal, and export. The findings
also showed that small enterprises faced more severe problems than
those of medium enterprises.
Abstract: Prior literature in the field of adaptive and
personalized learning sequence in e-learning have proposed and
implemented various mechanisms to improve the learning process
such as individualization and personalization, but complex to
implement due to expensive algorithmic programming and need of
extensive and prior data. The main objective of personalizing
learning sequence is to maximize learning by dynamically selecting
the closest teaching operation in order to achieve the learning
competency of learner. In this paper, a revolutionary technique has
been proposed and tested to perform individualization and
personalization using modified reversed roulette wheel selection
algorithm that runs at O(n). The technique is simpler to implement
and is algorithmically less expensive compared to other revolutionary
algorithms since it collects the dynamic real time performance matrix
such as examinations, reviews, and study to form the RWSA single
numerical fitness value. Results show that the implemented system is
capable of recommending new learning sequences that lessens time
of study based on student's prior knowledge and real performance
matrix.
Abstract: Inspired by the Formula-1 competition, IMechE
(Institute of Mechanical Engineers) and Formula SAE (Society of
Mechanical Engineers) organize annual competitions for University
and College students worldwide to compete with a single-seat racecar
they have designed and built. Design of the chassis or the frame is a
key component of the competition because the weight and stiffness
properties are directly related with the performance of the car and the
safety of the driver. In addition, a reduced weight of the chassis has
direct influence on the design of other components in the car. Among
others, it improves the power to weight ratio and the aerodynamic
performance. As the power output of the engine or the battery
installed in the car is limited to 80 kW, increasing the power to
weight ratio demands reduction of the weight of the chassis, which
represents the major part of the weight of the car. In order to reduce
the weight of the car, ION Racing team from University of
Stavanger, Norway, opted for a monocoque design. To ensure
fulfilment of the competition requirements of the chassis, the
monocoque design should provide sufficient torsional stiffness and
absorb the impact energy in case of possible collision. The study reported in this article is based on the requirements for
Formula Student competition. As part of this study, diverse
mechanical tests were conducted to determine the mechanical
properties and performances of the monocoque design. Upon a
comprehensive theoretical study of the mechanical properties of
sandwich composite materials and the requirements of monocoque
design in the competition rules, diverse tests were conducted
including 3-point bending test, perimeter shear test and test for
absorbed energy. The test panels were homemade and prepared with
equivalent size of the side impact zone of the monocoque, i.e. 275
mm x 500 mm, so that the obtained results from the tests can be
representative. Different layups of the test panels with identical core
material and the same number of layers of carbon fibre were tested
and compared. Influence of the core material thickness was also
studied. Furthermore, analytical calculations and numerical analysis
were conducted to check compliance to the stated rules for Structural
Equivalency with steel grade SAE/AISI 1010. The test results were
also compared with calculated results with respect to bending and
torsional stiffness, energy absorption, buckling, etc. The obtained results demonstrate that the material composition
and strength of the composite material selected for the monocoque
design has equivalent structural properties as a welded frame and thus
comply with the competition requirements. The developed analytical
calculation algorithms and relations will be useful for future
monocoque designs with different lay-ups and compositions.
Abstract: During the last decades, a number of food crises such
as Bovine Spongiform Encephalopathy (BSE), Mad-Cow disease,
Dioxin in chicken food, Food-and-Mouth Disease (FMD), have
certainly inflected the reliability of the food industry. Consequently,
the trend in applying different scientific methods of risk assessment
in food safety has obtained more attentions in the academic and
practice. However, lack of practical approach considering entire food
supply chain is tangible in the academic literature. In this regard, this
paper aims to apply risk assessment tool (FMEA) with integration of
Human Factor along the entire supply chain of food production and
test the method in a case study of Diary production, and analyze its
results.
Abstract: This paper aimed to introduce the solution of concrete
slump recovery using chemical admixture type-F (superplasticizer,
naphthalene base) to the practice in order to solve unusable concrete
problem due to concrete loss its slump, especially for those tropical
countries that have faster slump loss rate. In the other hand, randomly
adding superplasticizer into concrete can cause concrete to segregate.
Therefore, this paper also develops the estimation model used to
calculate amount of second dose of superplasticizer need for concrete
slump recovery. Fresh properties of ordinary Portland cement
concrete with volumetric ratio of paste to void between aggregate
(paste content) of 1.1-1.3 with water-cement ratio zone of 0.30 to
0.67 and initial superplasticizer (naphthalene base) of 0.25%-1.6%
were tested for initial slump and slump loss for every 30 minutes for
one and half hour by slump cone test. Those concretes with slump
loss range from 10% to 90% were re-dosed and successfully
recovered back to its initial slump. Slump after re-dosed was tested
by slump cone test. From the result, it has been concluded that, slump
loss was slower for those mix with high initial dose of
superplasticizer due to addition of superplasticizer will disturb
cement hydration. The required second dose of superplasticizer was
affected by two major parameters, which were water-cement ratio
and paste content, where lower water-cement ratio and paste content
cause an increase in require second dose of superplasticizer. The
amount of second dose of superplasticizer is higher as the solid
content within the system is increase, solid can be either from cement
particles or aggregate. The data was analyzed to form an equation use
to estimate the amount of second dosage requirement of
superplasticizer to recovery slump to its original.
Abstract: Large quantities of solid wastes being generated
worldwide from sources such as household, domestic, industrial,
commercial and construction demolition activities, leads to
environmental concerns. Utilization of these wastes in making
building construction materials can reduce the magnitude of the
associated problems. When these waste products are used in place of
other conventional materials, natural resources and energy are
preserved and expensive and/or potentially harmful waste disposal is
avoided. Recycling which is regarded as the third most preferred waste
disposal option, with its numerous environmental benefits, stand as a
viable option to offset the environmental impact associated with the
construction industry. This paper reviews the results of laboratory tests and important
research findings, and the potential of using these wastes in building
construction materials with focus on sustainable development.
Research gaps, which includes; the need to develop standard mix
design for solid waste based building materials; the need to develop
energy efficient method of processing solid waste use in concrete; the
need to study the actual behavior or performance of such building
materials in practical application and the limited real life application
of such building materials have also been identified. A research is being proposed to develop an environmentally
friendly, lightweight building block from recycled waste paper,
without the use of cement, and with properties suitable for use as
walling unit. This proposed research intends to incorporate,
laboratory experimentation and modeling to address the identified
research gaps.
Abstract: In this study, the effects and interactions of reaction
time and capping agent assistance during sol-gel synthesis of
magnesium substituted hydroxyapatite nanopowder (MgHA) on
hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) ratio, Ca/P
ratio and mean crystallite size was examined experimentally as well
as through statistical analysis. MgHA nanopowders were synthesized
by sol-gel technique at room temperature using aqueous solution of
calcium nitrate tetrahydrate, magnesium nitrate hexahydrate and
potassium dihydrogen phosphate as starting materials. The reaction
time for sol-gel synthesis was varied between 15 to 60 minutes. Two
process routes were followed with and without addition of
triethanolamine (TEA) in the solutions. The elemental compositions
of as-synthesized powders were determined using X-ray fluorescence
(XRF) spectroscopy. The functional groups present in the assynthesized
MgHA nanopowders were established through Fourier
Transform Infrared Spectroscopy (FTIR). The amounts of phases
present, Ca/P ratio and mean crystallite sizes of MgHA nanopowders
were determined using X-ray diffraction (XRD). The HA content in
biphasic mixture of HA and β-TCP and Ca/P ratio in as-synthesized
MgHA nanopowders increased effectively with reaction time of sols
(p0.15, two way ANOVA). The MgHA nanopowders
synthesized with TEA assistance exhibited 14 nm lower crystallite
size (p
Abstract: Response Surface Methods (RSM) provide
statistically validated predictive models that can then be manipulated
for finding optimal process configurations. Variation transmitted to
responses from poorly controlled process factors can be accounted
for by the mathematical technique of propagation of error (POE),
which facilitates ‘finding the flats’ on the surfaces generated by
RSM. The dual response approach to RSM captures the standard
deviation of the output as well as the average. It accounts for
unknown sources of variation. Dual response plus propagation of
error (POE) provides a more useful model of overall response
variation. In our case, we implemented this technique in predicting
compressive strength of concrete of 28 days in age. Since 28 days is
quite time consuming, while it is important to ensure the quality
control process. This paper investigates the potential of using design
of experiments (DOE-RSM) to predict the compressive strength of
concrete at 28th day. Data used for this study was carried out from
experiment schemes at university of Benghazi, civil engineering
department. A total of 114 sets of data were implemented. ACI mix
design method was utilized for the mix design. No admixtures were
used, only the main concrete mix constituents such as cement, coarseaggregate,
fine aggregate and water were utilized in all mixes.
Different mix proportions of the ingredients and different water
cement ratio were used. The proposed mathematical models are
capable of predicting the required concrete compressive strength of
concrete from early ages.
Abstract: The aim of this paper is to propose a general
framework for storing, analyzing, and extracting knowledge from
two-dimensional echocardiographic images, color Doppler images,
non-medical images, and general data sets. A number of high
performance data mining algorithms have been used to carry out this
task. Our framework encompasses four layers namely physical
storage, object identification, knowledge discovery, user level.
Techniques such as active contour model to identify the cardiac
chambers, pixel classification to segment the color Doppler echo
image, universal model for image retrieval, Bayesian method for
classification, parallel algorithms for image segmentation, etc., were
employed. Using the feature vector database that have been
efficiently constructed, one can perform various data mining tasks
like clustering, classification, etc. with efficient algorithms along
with image mining given a query image. All these facilities are
included in the framework that is supported by state-of-the-art user
interface (UI). The algorithms were tested with actual patient data
and Coral image database and the results show that their performance
is better than the results reported already.
Abstract: The purposes of this research are to make comparisons in
respect of the behaviors on the use of the services of metered taxi
classified by the demographic factor and to study the influence of the
recognition on service quality having the effect on usage behaviors of
metered taxi services of consumers in Bangkok Metropolitan Areas. The
samples used in this research were 400 metered taxi service users in
Bangkok Metropolitan Areas and questionnaire was used as the tool for
collecting the data. Analysis statistics are mean and multiple regression
analysis. Results of the research revealed that the consumers recognize the
overall quality of services in each aspect include tangible aspects of the
service, responses to customers, assurance on the confidence,
understanding and knowing of customers which is rated at the moderate
level except the aspect of the assurance on the confidence and
trustworthiness which are rated at a high level. For the result of
hypothetical test, it is found that the quality in providing the services on
the aspect of the assurance given to the customers has the effect on the
usage behaviors of metered taxi services and the aspect of the frequency
on the use of the services per month which in this connection. Such
variable can forecast at one point nine percent (1.9%). In addition, quality
in providing the services and the aspect of the responses to customers
have the effect on the behaviors on the use of metered taxi services on the
aspect of the expenses on the use of services per month which in this
connection, such variable can forecast at two point one percent (2.1%).
Abstract: Frozen shrimp industry plays an important role in the
development of production industry of the country. There has been a
continuing development to response the increasing demand; however,
there have been some problems in running the enterprises. The
purposes of this study are to: 1) investigate problems related to basic
factors in operating frozen shrimp industry based on the
entrepreneurs’ points of view. The enterprises involved in this study
were small and medium industry receiving Thai Frozen Foods
Association. 2) Compare the problems of the frozen shrimp industry
according to their sizes of operation in 3 provinces of the central
region Thailand. Population in this study consisted of 148 managers
from 148 frozen shrimp enterprises Thai Frozen Foods Association
which 77 were small size and 71 were medium size. The data were
analyzed to find percentage, arithmetic mean, standard deviation, and
independent sample T-test with the significant hypothesis at .05. The
results revealed that the problems of the frozen shrimp industries of
both size were in high level. The needs for government supporting
were in high level. The comparison of the problems and the basic
factors between the small and medium size enterprises showed no
statistically significant level. The problems that they mentioned
included raw materials, labors, production, marketing, and the need
for academic supporting from the government sector.
Abstract: The Haussmannization plan of Cairo in 1867 formed a
regular network of roundabout spaces, though deteriorated at present.
The method of identifying the spatial structure of roundabout Cairo
for conservation matches the voronoi diagram with the space syntax
through their geometrical property of spatial convexity. In this
initiative, the primary convex hull of first-order voronoi adopts the
integral and control measurements of space syntax on Cairo’s
roundabout generators. The functional essence of royal palaces
optimizes the roundabout structure in terms of spatial measurements
and the symbolic voronoi projection of 'Tahrir Roundabout' over the
Giza Nile and Pyramids. Some roundabouts of major public and
commercial landmarks surround the pole of 'Ezbekia Garden' with a
higher control than integral measurements, which filter the new
spatial structure from the adjacent traditional town. Nevertheless, the
least integral and control measures correspond to the voronoi
contents of pollutant workshops and the plateau of old Cairo Citadel
with the visual compensation of new royal landmarks on top.
Meanwhile, the extended suburbs of infinite voronoi polygons
arrange high control generators of chateaux housing in 'garden city'
environs. The point pattern of roundabouts determines the
geometrical characteristics of voronoi polygons. The measured
lengths of voronoi edges alternate between the zoned short range at
the new poles of Cairo and the distributed structure of longer range.
Nevertheless, the shortest range of generator-vertex geometry
concentrates at 'Ezbekia Garden' where the crossways of vast Cairo
intersect, which maximizes the variety of choice at different spatial
resolutions. However, the symbolic 'Hippodrome' which is the largest
public landmark forms exclusive geometrical measurements, while
structuring a most integrative roundabout to parallel the royal syntax.
Overview of the symbolic convex hull of voronoi with space syntax
interconnects Parisian Cairo with the spatial chronology of scattered
monuments to conceive one universal Cairo structure. Accordingly,
the approached methodology of 'voronoi-syntax' prospects the future
conservation of roundabout Cairo at the inferred city-level concept.
Abstract: Coal fly ash, an industrial by product of coal
combustion thermal power plants is considered as a hazardous
material and its improper disposal has become an environmental
issue. On the other hand, manufacturing conventional clay bricks
involves on consumption of large amount of clay and leads
substantial depletion of topsoil. This paper unveils the possibility of
using fly ash as a partial replacement of clay for brick manufacturing
considering the local technology practiced in Bangladesh. The effect
of fly ash with different replacing ratio (0%, 20%, 30%, 40%, and
50% by volume) of clay on properties of bricks was studied. Bricks
were made in the field parallel to ordinary bricks marked with
specific number for different percentage to identify them at time of
testing. No physical distortion is observed in fly ash brick after
burning in the kiln. Results from laboratory test show that
compressive strength of brick is decreased with the increase of fly
ash and maximum compressive strength is found to be 19.6 MPa at
20% of fly ash. In addition, water absorption of fly ash brick is
increased with the increase of fly ash. The abrasion value and
Specific gravity of coarse aggregate prepared from brick with fly ash
also studied and the results of this study suggests that 20% fly ash
can be considered as the optimum fly ash content for producing good
quality bricks utilizing present practiced technology.
Abstract: Agricultural machinery industry plays an important
role in the industrial development especially the production industry
of the country. There has been continuing development responding to
the higher demand of the production. However, the problem in
agricultural machinery production still exists. Thus, the purpose of
this research is to investigate problems on fundamental factors of
industry based on the entrepreneurs’ point of view. The focus was on
the small and medium size industry receiving factory license type
number 0660 from the Department of Industrial Works. The
investigation was on the comparison between the management of the
small and medium size agricultural industry in 3 provinces in the
central region of Thailand. Population in this study consisted of 189
company managers or managing directors, of which 101 were from
the small size and 88 were from the medium size industry. The data
were analyzed to find percentage, arithmetic mean, and standard
deviation with independent sample T-test at the statistical
significance .05. The results showed that the small and medium size
agricultural machinery manufacturers in the central region of
Thailand reported high problems in every aspect. When compared the
problems on basic factors in running the business, it was found that
there was no statistically difference at .05 in managing of the small
and medium size agricultural machinery manufacturers. However,
there was a statistically significant difference between the small and
medium size agricultural machinery manufacturers on the aspect of
policy and services of the government. The problems reported by the
small and medium size agricultural machinery manufacturers were
the services on public tap water and the problem on politic and
stability of the country.
Abstract: Job satisfaction and motivation have been given an
important attention in psychology because they are seen as main
instruments in maintaining organizational growth and development;
they are also used to accomplish organizational aims and objectives.
However, it has been observed that some institutions failed in
motivating and stimulating their workers; in contrast, workers may be
motivated but not satisfied with the job and failed to perform
efficiently and effectively. It is hoped that the study of this nature
would be of significance value to all stakeholders in education
specifically, lecturers in higher institutions in Nigeria. Also, it is
hoped that the findings of this study will enhance lecturers’
effectiveness and performance in discharging their duties. In the light
of the above statements, this study investigated whether job
satisfaction and motivation predict lecturers’ effectiveness in Nigeria
Police Academy, Wudil, Kano State. Correlational research method
was adopted for the study, while purposive sampling technique was
used to choose the institution and the sampled lectures (70). Simple
random sampling technique was used to select one hundred cadets
across the academy. Two instruments were used to elicit information
from both lecturers and cadets. These were job satisfaction and
motivation; and lecturers’ effectiveness Questionnaires. The
instruments were subjected to pilot testing and found to have
reliability coefficient of 0.69 and 0.71 respectively. The results of the
study revealed that there was a significance relationship among job
satisfaction, motivation and lecturers effectiveness in Nigeria Police
Academy. There was a significance relationship between job
satisfaction and lecturers’ effectiveness in Nigeria Police Academy
the cal r is 0.21 while the crt r is 0.19. at p
Abstract: We regard forecasting of energy consumption by
private production areas of a large industrial facility as well as by the
facility itself. As for production areas, the forecast is made based on
empirical dependencies of the specific energy consumption and the
production output. As for the facility itself, implementation of the
task to minimize the energy consumption forecasting error is based
on adjustment of the facility’s actual energy consumption values
evaluated with the metering device and the total design energy
consumption of separate production areas of the facility. The
suggested procedure of optimal energy consumption was tested based
on the actual data of core product output and energy consumption by
a group of workshops and power plants of the large iron and steel
facility. Test results show that implementation of this procedure gives
the mean accuracy of energy consumption forecasting for winter
2014 of 0.11% for the group of workshops and 0.137% for the power
plants.
Abstract: Gladiolus is an important cash crop and is grown
mainly for its elegant spikes. Traditionally the gladiolus corms are
planted manually which is very tedious, time consuming and labor
intensive operation. So far, there is no planter available for planting
of gladiolus corms. With a view to mechanize the planting operation
of this horticultural crop, a prototype of 4-row gladiolus planter was
developed and its performance was evaluated in-situ condition. Cupchain
type metering device was used to place each single gladiolus
corm in furrow at required spacing while planting. Three levels of
corm spacing viz 15, 20 and 25 cm and four levels of forward speed
viz 1.0, 1.5, 2.0 and 2.5 km/h was taken as evaluation parameter for
the planter. The performance indicators namely corm spacing in each
row, coefficient of uniformity, missing index, multiple index, quality
of feed index, number of corms per meter length, mechanical damage
to the corms etc. were determined during the field test. The data was
statistically analyzed using Completely Randomized Design (CRD)
for testing the significance of the parameters. The result indicated
that planter was able to drop the corms at required nominal spacing
with minor variations. The highest deviation from the mean corm
spacing was observed as 3.53 cm with maximum coefficient of
variation as 13.88%. The highest missing and quality of feed indexes
were observed as 6.33% and 97.45% respectively with no multiples.
The performance of the planter was observed better at lower forward
speed and wider corm spacing. The field capacity of the planter was
found as 0.103 ha/h with an observed field efficiency of 76.57%.
Abstract: Sentiment analysis means to classify a given review
document into positive or negative polar document. Sentiment
analysis research has been increased tremendously in recent times
due to its large number of applications in the industry and academia.
Sentiment analysis models can be used to determine the opinion of
the user towards any entity or product. E-commerce companies can
use sentiment analysis model to improve their products on the basis
of users’ opinion. In this paper, we propose a new One-class Support
Vector Machine (One-class SVM) based sentiment analysis model
for movie review documents. In the proposed approach, we initially
extract features from one class of documents, and further test the
given documents with the one-class SVM model if a given new test
document lies in the model or it is an outlier. Experimental results
show the effectiveness of the proposed sentiment analysis model.
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.