Abstract: Solar water heating is a thermodynamic process of
heating water using sunlight with the help of solar water heater. Thus,
solar water heater is a device used to harness solar energy. In this
paper, a modified solar water heating system (MSWHS) has been
proposed over flat plate collector (FPC) and Evacuated tube collector
(ETC). The modifications include selection of materials other than
glass, and glass wool which are conventionally used for fabricating
FPC and ETC. Some modifications in design have also been
proposed. Its collector is made of double layer of semi-cylindrical
acrylic tubes and fibre reinforced plastic (FRP) insulation base. Water
tank is made of double layer of acrylic sheet except base and north
wall. FRP is used in base and north wall of the water tank. A concept
of equivalent thickness has been utilised for calculating the
dimensions of collector plate, acrylic tube and tank. A thermal model for the proposed design of MSWHS is developed
and simulation is carried out on MATLAB for the capacity of 200L
MSWHS having collector area of 1.6 m2, length of acrylic tubes of
2m at an inclination angle 25° which is taken nearly equal to the
latitude of the given location. Latitude of Allahabad is 24.45° N. The
results show that the maximum temperature of water in tank and tube
has been found to be 71.2°C and 73.3°C at 17:00hr and 16:00hr
respectively in March for the climatic data of Allahabad. Theoretical performance analysis has been carried out by varying
number of tubes of collector, the tank capacity and climatic data for
given months of winter and summer.
Abstract: In this paper, we present the design of the
super-ellipsoidal potential function (SEPF), that can be used for
autonomous collision avoidance of an unmanned aerial vehicle (UAV)
in a 3-dimensional space. In the design of SEPF, we have the
full control over the shape and size of the potential function. In
particular, we can adjust the length, width, height, and the amount
of flattening at the tips of the potential function so that the collision
avoidance motion vector generated from the potential function can
be adjusted accordingly. Based on the idea of the SEPF, we also
propose an approach for the local autonomy of a UAV for its collision
avoidance when the UAV is teleoperated by a human operator. In
our proposed approach, a teleoperated UAV can not only avoid
collision autonomously with other surrounding objects but also track
the operator’s control input as closely as possible. As a result, an
operator can always be in control of the UAV for his/her high-level
guidance and navigation task without worrying too much about
the UAVs collision avoidance while it is being teleoperated. The
effectiveness of the proposed approach is demonstrated through a
human-in-the-loop simulation of quadrotor UAV teleoperation using
virtual robot experimentation platform (v-rep) and Matlab programs.
Abstract: The railway transport is considered as a one of the
most environmentally friendly mode of transport. With future
prediction of increasing of freight transport there are lines facing
problems with demanded capacity. Increase of the track capacity
could be achieved by infrastructure constructive adjustments. The
contribution shows how the travel time can be minimized and the
track capacity increased by changing some of the basic infrastructure
and operation parameters, for example, the minimal curve radius of
the track, the number of tracks, or the usable track length at stations.
Calculation of the necessary parameter changes is based on the
fundamental physical laws applied to the train movement, and
calculation of the occupation time is dependent on the changes of
controlling the traffic between the stations.
Abstract: A composite material with carbon fiber and polymer
matrix has been used as adherent for manufacturing adhesive joints.
In order to evaluate different fiber orientations on joint performance,
the adherents with the 0°, ±15°, ±30°, ±45° fiber orientations were
used in the single lap joint configuration. The joints with an overlap
length of 25 mm were prepared according to the ASTM 1002
specifications and subjected to tensile loadings. The structural
adhesive used was a two-part epoxy to be cured at 70°C for an hour.
First, mechanical behaviors of the adherents were measured using
three point bending test. In the test, considerations were given to
stress to failure and elastic modulus. The results were compared with
theoretical ones using rule of mixture. Then, the joints were
manufactured in a specially prepared jig, after a proper surface
preparation. Experimental results showed that the fiber orientations
of the adherents affected the joint performance considerably; the
joints with ±45° adherents experienced the worst shear strength, half
of those with 0° adherents, and in general, there was a great
relationship between the fiber orientations and failure mechanisms.
Delamination problems were observed for many joints, which were
thought to be due to peel effects at the ends of the overlap. It was
proved that the surface preparation applied to the adherent surface
was adequate. For further explanation of the results, a numerical
work should be carried out using a possible non-linear analysis.
Abstract: The maintenance of work rolls in hot strip processing
has been lengthy and difficult tasks for hot strip manufacturer
because heavy work rolls have to be taken out of the production line,
which could take hours. One way to increase the time between
maintenance is to improve the effectiveness of the work roll cooling
system such that the wear and tear more slowly occurs, while the
operation cost is kept low. Therefore, this study aims to improve the
work roll cooling system by providing the manufacturer the
relationship between the work-roll temperature reduced by cooling
and the water flow that can help manufacturer determining the more
effective water flow of the cooling system. The relationship is found
using simulation with a systematic process adjustment so that the
satisfying quality of product is achieved. Results suggest that the
manufacturer could reduce the water flow by 9% with roughly the
same performance. With the same process adjustment, the feasibility
of finishing-mill-stand reduction is also investigated. Results suggest
its possibility.
Abstract: The Hall Coefficient (HC) and the Magnetoresistance (MR) have been studied in two-dimensional systems. The HC and the MR in Rectangular Quantum Wire (RQW) subjected to a crossed DC electric field and magnetic field in the presence of a Strong Electromagnetic Wave (EMW) characterized by electric field are studied in this work. Using the quantum kinetic equation for electrons interacting with optical phonons, we obtain the analytic expressions for the HC and the MR with a dependence on magnetic field, EMW frequency, temperatures of systems and the length characteristic parameters of RQW. These expressions are different from those obtained for bulk semiconductors and cylindrical quantum wires. The analytical results are applied to GaAs/GaAs/Al. For this material, MR depends on the ratio of the EMW frequency to the cyclotron frequency. Indeed, MR reaches a minimum at the ratio 5/4, and when this ratio increases, it tends towards a saturation value. The HC can take negative or positive values. Each curve has one maximum and one minimum. When magnetic field increases, the HC is negative, achieves a minimum value and then increases suddenly to a maximum with a positive value. This phenomenon differs from the one observed in cylindrical quantum wire, which does not have maximum and minimum values.
Abstract: In this paper, the regression dependence of dancing
intensity from wind speed and length of span was established due to
the statistic data obtained from multi-year observations on line wires
dancing accumulated by power systems of Kazakhstan and the
Russian Federation. The lower and upper limitations of the equations
parameters were estimated, as well as the adequacy of the regression
model. The constructed model will be used in research of dancing
phenomena for the development of methods and means of protection
against dancing and for zoning plan of the territories of line wire
dancing.
Abstract: This paper presents the performance characteristics of
Darrieus-type vertical axis wind turbine (VAWT) with NACA airfoil
blades. The performance of Darrieus-type VAWT can be
characterized by torque and power. There are various parameters
affecting the performance such as chord length, helical angle, pitch
angle and rotor diameter. To estimate the optimum shape of Darrieustype
wind turbine in accordance with various design parameters, we
examined aerodynamic characteristics and separated flow occurring
in the vicinity of blade, interaction between flow and blade, and
torque and power characteristics derived from it. For flow analysis,
flow variations were investigated based on the unsteady RANS
(Reynolds-averaged Navier-Stokes) equation. Sliding mesh algorithm
was employed in order to consider rotational effect of blade. To
obtain more realistic results we conducted experiment and numerical
analysis at the same time for three-dimensional shape. In addition,
several parameters (chord length, rotor diameter, pitch angle, and
helical angle) were considered to find out optimum shape design and
characteristics of interaction with ambient flow. Since the NACA
airfoil used in this study showed significant changes in magnitude of
lift and drag depending on an angle of attack, the rotor with low drag,
long cord length and short diameter shows high power coefficient in
low tip speed ratio (TSR) range. On the contrary, in high TSR range,
drag becomes high. Hence, the short-chord and long-diameter rotor
produces high power coefficient. When a pitch angle at which airfoil
directs toward inside equals to -2° and helical angle equals to 0°,
Darrieus-type VAWT generates maximum power.
Abstract: This paper describes an ab-initio design, development and calibration results of an Optical Sensor Ground Reaction Force Measurement Platform (OSGRFP) for gait and geriatric studies. The developed system employs an array of FBG sensors to measure the respective ground reaction forces from all three axes (X, Y and Z), which are perpendicular to each other. The novelty of this work is two folded. One is in its uniqueness to resolve the tri axial resultant forces during the stance in to the respective pure axis loads and the other is the applicability of inherently advantageous FBG sensors which are most suitable for biomechanical instrumentation. To validate the response of the FBG sensors installed in OSGRFP and to measure the cross sensitivity of the force applied in other directions, load sensors with indicators are used. Further in this work, relevant mathematical formulations are presented for extracting respective ground reaction forces from wavelength shifts/strain of FBG sensors on the OSGRFP. The result of this device has implications in understanding the foot function, identifying issues in gait cycle and measuring discrepancies between left and right foot. The device also provides a method to quantify and compare relative postural stability of different subjects under test, which has implications in post-surgical rehabilitation, geriatrics and optimizing training protocols for sports personnel.
Abstract: Purpose: The key aim of the research was to identify
the secondary stressors experienced by businesses affected by single
or repeated flooding and to determine to what extent businesses were
affected by these stressors, along with any resulting impact on health.
Additionally the research aimed to establish the likelihood of
businesses being re-exposed to the secondary stressors through
assessing awareness of flood risk, implementation of property
protection measures and level of community resilience. Design/methodology/approach: The chosen research method
involved the distribution of a questionnaire survey to businesses
affected by either single or repeated flood events. The questionnaire
included the Impact of Event Scale (a 15-item self-report measure
which assesses subjective distress caused by traumatic events). Findings: 55 completed questionnaires were returned by flood
impacted businesses. 89% of the businesses had sustained internal
flooding, while 11% had experienced external flooding. The results
established that the key secondary stressors experienced by
businesses, in order of priority, were: flood damage, fear of
reoccurring flooding, prevention of access to the premise/closure,
loss of income, repair works, length of closure and insurance issues.
There was a lack of preparedness for potential future floods and
consequent vulnerability to the emergence of secondary stressors
among flood affected businesses, as flood resistance or flood
resilience measures had only been implemented by 11% and 13%
respectively. In relation to the psychological repercussions, the
Impact of Event scores suggested that potential prevalence of posttraumatic
stress disorder (PTSD) was noted among 8 out of 55
respondents (l5%). Originality/value: The results improve understanding of the
enduring repercussions of flood events on businesses, indicating that
not only residents may be susceptible to the detrimental health
impacts of flood events and single flood events may be just as likely
as reoccurring flooding to contribute to ongoing stress. Lack of
financial resources is a possible explanation for the lack of
implementation of property protection measures among businesses,
despite 49% experiencing flooding on multiple occasions. Therefore
it is recommended that policymakers should consider potential
sources of financial support or grants towards flood defences for
flood impacted businesses. Any form of assistance should be made
available to businesses at the earliest opportunity as there was no
significant association between the time of the last flood event and
the likelihood of experiencing PTSD symptoms.
Abstract: Fractal based digital image compression is a specific
technique in the field of color image. The method is best suited for
irregular shape of image like snow bobs, clouds, flame of fire; tree
leaves images, depending on the fact that parts of an image often
resemble with other parts of the same image. This technique has
drawn much attention in recent years because of very high
compression ratio that can be achieved. Hybrid scheme incorporating
fractal compression and speedup techniques have achieved high
compression ratio compared to pure fractal compression. Fractal
image compression is a lossy compression method in which selfsimilarity
nature of an image is used. This technique provides high
compression ratio, less encoding time and fart decoding process. In
this paper, fractal compression with quad tree and DCT is proposed
to compress the color image. The proposed hybrid schemes require
four phases to compress the color image. First: the image is
segmented and Discrete Cosine Transform is applied to each block of
the segmented image. Second: the block values are scanned in a
zigzag manner to prevent zero co-efficient. Third: the resulting image
is partitioned as fractals by quadtree approach. Fourth: the image is
compressed using Run length encoding technique.
Abstract: In language learning, second language learners as well
as Native speakers commit errors in their attempt to achieve
competence in the target language. The realm of collocation has to do
with meaning relation between lexical items. In all human language,
there is a kind of ‘natural order’ in which words are arranged or relate
to one another in sentences so much so that when a word occurs in a
given context, the related or naturally co-occurring word will
automatically come to the mind. It becomes an error, therefore, if
students inappropriately pair or arrange such ‘naturally’ co–occurring
lexical items in a text. It has been observed that most of the second
language learners in this research group commit collocation errors. A
study of this kind is very significant as it gives insight into the kinds
of errors committed by learners. This will help the language teacher
to be able to identify the sources and causes of such errors as well as
correct them thereby guiding, helping and leading the learners
towards achieving some level of competence in the language. The
aim of the study is to understand the nature of these errors as
stumbling blocks to effective essay writing. The objective of the
study is to identify the errors, analyze their structural compositions so
as to determine whether there are similarities between students in this
regard and to find out whether there are patterns to these kinds of
errors which will enable the researcher to understand their sources
and causes. As a descriptive research, the researcher samples some
nine hundred essays collected from three hundred undergraduate
learners of English as a second language in the Federal College of
Education, Kano, North- West Nigeria, i.e. three essays per each
student. The essays which were given on three different lecture times
were of similar thematic preoccupations (i.e. same topics) and length
(i.e. same number of words). The essays were written during the
lecture hour at three different lecture occasions. The errors were
identified in a systematic manner whereby errors so identified were
recorded only once even if they occur severally in students’ essays.
The data was collated using percentages in which the identified
numbers of occurrences were converted accordingly in percentages.
The findings from the study indicate that there are similarities as well
as regular and repeated errors which provided a pattern. Based on the
pattern identified, the conclusion is that students’ collocation errors
are attributable to poor teaching and learning which resulted in wrong
generalization of rules.
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: In this study, Brillouin Gain Spectrum (BGS) is
experimentally analyzed in the Brillouin Optical Time Domain
Reflectometry (BOTDR) and Brillouin Optical Time Domain
Analyzer (BOTDA). For this purpose, the signal level of the
microwave generator is varied and the effects of BGS are
investigated. In the setups, 20 km conventional single mode fiber is
used to both setups and laser wavelengths are selected around 1550
nm. To achieve best results, it can be used between 5 dBm to 15 dBm
signal level of microwave generator for BOTDA and BOTDR setups.
Abstract: Wavelength Division Multiplexing (WDM)
technology is the most promising technology for the proper
utilization of huge raw bandwidth provided by an optical fiber. One
of the key problems in implementing the all-optical WDM network is
the packet contention. This problem can be solved by several
different techniques. In time domain approach the packet contention
can be reduced by incorporating Fiber Delay Lines (FDLs) as optical
buffer in the switch architecture. Different types of buffering
architectures are reported in literatures. In the present paper a
comparative performance analysis of three most popular FDL
architectures are presented in order to obtain the best contention
resolution performance. The analysis is further extended to consider
the effect of different fiber non-linearities on the network
performance.
Abstract: This study investigated the effects of thermal
treatment on Tualang honey sample in terms of honey colour and
heat-induced small metabolites. The heating process was carried out
in a temperature controlled water batch at 90oC for 4 hours. The
honey samples were put in cylinder tubes with the dimension of 1 cm
diameter and 10 cm length for homogenous heat transfer. The results
found that the thermal treatment produced not only
hydroxylmethylfurfural, but also other harmful substances such as
phthalic anhydride and radiolytic byproducts. The degradation of
honey protein was due to the detection of free amino acids such as
cysteine and phenylalanine in heat-treated honey samples. Sugar
dehydration was also occurred because fragmented di-galactose was
identified based on the presence of characteristic ions in the mass
fragmentation pattern. The honey colour was found getting darker as
the heating duration was increased up to 4 hours. Approximately, 60
mm PFund of increment was noticed for the honey colour with the
colour change rate of 14.8 mm PFund per hour. Based on the
principal component analysis, the score plot clearly shows that the
chemical profile of Tualang honey was significantly altered after 2
hours of heating at 90oC.
Abstract: This paper presents numerical analysis in terms of
buckling resistance of GFRP sandwich infill panels system under the
influence of increased temperature on the foam core. Failure mode
under in-plane compression is studied by means of numerical analysis
with ABAQUS platform. Parameters considered in this study are
contact length and both the type of foam for core and the variation of
its module elastic under the thermal influence. Increment of
temperature is considered in static cases and only applied to core.
Indeed, it is proven that the effect of temperature alters the mechanical
properties of the entire panel system. Moreover, the rises of
temperature result in a decrease in strength of the panel. This is due to
the polymeric nature of this material. Additionally, the contact length
also displays the effect on performance of infill panel. Their
significance factors are based on type of polymer for core. Therefore,
by comparing difference type of core material, the variation can be
reducing.
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: 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%.