Abstract: The performances of a thermoacoustic travelling-wave
refrigerator are presented. Developed in the frame of the European
project called THATEA, it is designed for providing 600 W at a
temperature of 233 K with an efficiency of 40 % relative to the
Carnot efficiency. This paper presents the device and the results of
the first measurements. For a cooling power of 210 W, a coefficient
of performance relative to Carnot of 30 % is achieved when the
refrigerator is coupled with an existing standing-wave engine.
Abstract: Detection and recognition of the Human Body Composition and extraction their measures (width and length of human body) in images are a major issue in detecting objects and the important field in Image, Signal and Vision Computing in recent years. Finding people and extraction their features in Images are particularly important problem of object recognition, because people can have high variability in the appearance. This variability may be due to the configuration of a person (e.g., standing vs. sitting vs. jogging), the pose (e.g. frontal vs. lateral view), clothing, and variations in illumination. In this study, first, Human Body is being recognized in image then the measures of Human Body extract from the image.
Abstract: According to investigating impact of complexity of
stereoscopic frame pairs on stereoscopic video coding and
transmission, a new rate control algorithm is presented. The proposed
rate control algorithm is performed on three levels: stereoscopic group
of pictures (SGOP) level, stereoscopic frame (SFrame) level and
frame level. A temporal-spatial frame complexity model is firstly
established, in the bits allocation stage, the frame complexity, position
significance and reference property between the left and right frames
are taken into account. Meanwhile, the target buffer is set according to
the frame complexity. Experimental results show that the proposed
method can efficiently control the bitrates, and it outperforms the fixed
quantization parameter method from the rate distortion perspective,
and average PSNR gain between rate-distortion curves (BDPSNR) is
0.21dB.
Abstract: The efficacy of the separate mixing of four tropical spicy and medicinal plant products: Dennettia tripetala Baker (pepper fruit), Eugenia aromatica Hook (clove), Piper guineense (Schum and Thonn) (black pepper) and Monodora myristica (Dunal) (African nut-meg) with a household vegetable oil was evaluated under tropical storage conditions for the control and reproductive performance of Dermestes maculatus (De Geer) (hide beetle) and Necroba rufipes (De Geer) (copra beetle) on African catfish, Clarias gariepinus (Burchell). Each of the plant materials was pulverized into powder and applied as a mix of 1ml of oil and plant powder at 2.5, 5.0, 7.5 and 10.0g per 100g of dried fish, and allowed to dry for 6h. Each of the four oil-mixed powder treatments evoked significant (P < 05) mortalities of the two insects compared with the control (oil only) at 1, 3 and 7 days post treatment. The oil-powder mixture dosages did not prevent insect egg hatchability but while the emergent larvae on the treated samples died, the emergent larvae in the control survived into adults. The application of oil-mixed powders effectively suppressed the emergence of the larvae of the beetles. Similarly, each of the oil-powder mixtures significantly reduced weight loss in smoked fish that were exposed to D. maculatus and N. rufipes when compared to the control (P < 05). The results of this study suggest that the plant powders rather than the domestic oil demonstrated protective ability against the fish beetles and confirm the efficacy of the plant products as pest control agents.
Abstract: The Taiwan government has invested approximately
21 billion NT dollars in the construction of bicycle paths since
bicycling has gained huge popularity as a healthy leisure and
recreational activity. This study focuses on the behavior of
recreational bicyclists in Danshuei and Bali, northern Taiwan. Data
were collected from a field investigation carried out along the
Danshuei bicycle path and Bali left-bank bicycle path. A total of 578
questionnaires were gathered for data analysis. Descriptive statistics
and Chi-Square tests were used to assess bicyclists- behaviors. The
frequency shows that, in these areas, Danshuei and Bali, most
bicyclists rented bicycles, rode the bicycle path in the afternoon for
about 2 hours. The used the bicycle path one time per week. For most,
it was the first time to ride these bicycle paths. There were significant
differences in distribution of bicycle ownership, time of day, duration
of ride, ride frequency, and whether riding occurred on weekdays or
weekends. Results indicated that most bicyclists in Danshuei and Bali
were infrequent users.
Abstract: This paper deals with the analysis of active constrained layer damping (ACLD) of doubly curved laminated composite shells using active fiber composite (AFC) materials. The constraining layer of the ACLD treatment has been considered to be made of the AFC materials. A three dimensional energy based finite element model of the smart doubly curved laminated composite shell integrated with a patch of such ACLD treatment has been developed to demonstrate the performance of the patch on enhancing the damping characteristics of the doubly curved laminated composite shells. Particular emphasis has been placed on studying the effect of variation of piezoelectric fiber orientation angle in the constraining AFC layer on the control authority of the ACLD patch.
Abstract: The aim of this paper is to determine Frenet-Serret invariants of non-null curves in Lorentzian 5-space. First, we define a vector product of four vectors, by this way, we present a method to calculate Frenet-Serret invariants of the non-null curves. Additionally, an algebraic example of presented method is illustrated.
Abstract: The counter flow solar air heaters, with four
transverse fins and wire mesh layers are constructed and investigated
experimentally for thermal efficiency at a geographic location of
Cyprus in the city of Famagusta. The absorber plate is replaced by
sixteen steel wire mesh layers, 0.18 x 0.18cm in cross section
opening and a 0.02cm in diameter. The wire mesh layers arranged in
three groups, first and second include 6 layers, while the third include
4 layers. All layers fixed in the duct parallel to the glazing and each
group separated from the others by wood frame thickness of 0.5cm to
reduce the pressure drop. The transverse fins arranged in a way to
force the air to flow through the bed like eight letter path with flow
depth 3cm. The proposed design has increased the heat transfer rate,
but on other hand causes a high pressure drop. The obtained results
show that, for air mass flow rate range between 0.011-0.036kg/s, the
thermal efficiency increases with increasing the air mass flow. The
maximum efficiency obtained is 65.6% for the mass flow rate of
0.036kg/s. Moreover, the temperature difference between the outlet
flow and the ambient temperature, ΔT, reduces as the air mass flow
rate increase. The maximum difference between the outlet and
ambient temperature obtained was 43°C for double pass for minimum
mass flow rate of 0.011kg/s. Comparison with a conventional solar
air heater collector shows a significantly development in the thermal
efficiency.
Abstract: This paper presents the development of a hybrid
thermal model for the EVO Electric AFM 140 Axial Flux Permanent
Magnet (AFPM) machine as used in hybrid and electric vehicles. The
adopted approach is based on a hybrid lumped parameter and finite
difference method. The proposed method divides each motor
component into regular elements which are connected together in a
thermal resistance network representing all the physical connections
in all three dimensions. The element shape and size are chosen
according to the component geometry to ensure consistency. The
fluid domain is lumped into one region with averaged heat transfer
parameters connecting it to the solid domain. Some model parameters
are obtained from Computation Fluid Dynamic (CFD) simulation and
empirical data. The hybrid thermal model is described by a set of
coupled linear first order differential equations which is discretised
and solved iteratively to obtain the temperature profile. The
computation involved is low and thus the model is suitable for
transient temperature predictions. The maximum error in temperature
prediction is 3.4% and the mean error is consistently lower than the
mean error due to uncertainty in measurements. The details of the
model development, temperature predictions and suggestions for
design improvements are presented in this paper.
Abstract: The quality-of-service (QoS) support for wireless
LANs has been a hot research topic during the past few years. In this paper, two QoS provisioning mechanisms are proposed for the employment in 802.11e EDCA MAC scheme. First, the proposed call
admission control mechanism can not only guarantee the QoS for the higher priority existing connections but also provide the minimum reserved bandwidth for traffic flows with lower priority. In addition, the adaptive contention window adjustment mechanism can adjust the
maximum and minimum contention window size dynamically according to the existing connection number of each AC. The collision
probability as well as the packet delay will thus be reduced effectively.
Performance results via simulations have revealed the enhanced QoS property achieved by employing these two mechanisms.
Abstract: The aim of this paper is to study the internal
stabilization of the Bernoulli-Euler equation numerically. For this,
we consider a square plate subjected to a feedback/damping force
distributed only in a subdomain. An algorithm for obtaining an
approximate solution to this problem was proposed and implemented.
The numerical method used was the Finite Difference Method.
Numerical simulations were performed and showed the behavior of
the solution, confirming the theoretical results that have already been
proved in the literature. In addition, we studied the validation of the
numerical scheme proposed, followed by an analysis of the numerical
error; and we conducted a study on the decay of the energy associated.
Abstract: Launch and recovery helicopter wind envelope for a
ship type was determined as the first step to the helicopter
qualification program. Flight deck velocities data were obtained by
means of a two components laser Doppler anemometer testing a
1/50th model in the wind tunnel stream. Full-scale flight deck
measurements were obtained on board the ship using a sonic
anemometer. Wind tunnel and full-scale measurements were
compared, showing good agreement and finally, a preliminary launch
and recovery helicopter wind envelope for this specific ship was
built.
Abstract: This paper provides a replacement policy for warranty products with different failure rate from the consumer-s viewpoint. Assume that the product is replaced once within a finite planning horizon, and the failure rate of the second product is lower than the failure rate of the first product. Within warranty period (WP), the failed product is corrected by minimal repair without any cost to the consumers. After WP, the failed product is repaired with a fixed repair cost to the consumers. However, each failure incurs a fixed downtime cost to the consumers over a finite planning horizon. In this paper, we derive the model of the expected total disbursement cost within a finite planning horizon and some properties of the optimal replacement policy under some reasonable conditions are obtained. Finally, numerical examples are given to illustrate the features of the optimal replacement policy under various maintenance costs.
Abstract: This paper presents a modified version of the
maximum urgency first scheduling algorithm. The maximum
urgency algorithm combines the advantages of fixed and dynamic
scheduling to provide the dynamically changing systems with
flexible scheduling. This algorithm, however, has a major
shortcoming due to its scheduling mechanism which may cause a
critical task to fail. The modified maximum urgency first scheduling
algorithm resolves the mentioned problem. In this paper, we propose
two possible implementations for this algorithm by using either
earliest deadline first or modified least laxity first algorithms for
calculating the dynamic priorities. These two approaches are
compared together by simulating the two algorithms. The earliest
deadline first algorithm as the preferred implementation is then
recommended. Afterwards, we make a comparison between our
proposed algorithm and maximum urgency first algorithm using
simulation and results are presented. It is shown that modified
maximum urgency first is superior to maximum urgency first, since it
usually has less task preemption and hence, less related overhead. It
also leads to less failed non-critical tasks in overloaded situations.
Abstract: This paper proposes a resonant dc link in PWM ac
chopper. This can solve the spike problems and also reduce the
switching loss. The configuration and PWM pattern of the proposed
technique are presented. The simulation results are used to confirm
the theory.
Abstract: Nowadays for algae cell ultrasonication the
longitudinal ultrasonic piezosystems are used. In this paper a
possibility of creating unique ultrasonic piezoelectric system, which
would allow reducing energy losses and concentrating this energy to
a small closed volume are proposed. The current vibrating systems
whose ultrasonic energy is concentrated inside of hollow cylinder in
which water-algae mixture is flowing. Two, three or multiply
ultrasonic composite systems to concentrate total energy into a
hollow cylinder to creating strong algae cell ultrasonication are used.
The experiments and numerical FEM analysis results using diskshaped
transducer and the first biological test results on algae cell
disruption by ultrasonication are presented as well.
Abstract: This paper deals with the experimental investigations
of the in-cylinder tumble flows in an unfired internal combustion
engine with a flat piston at the engine speeds ranging from 400 to
1000 rev/min., and also with the dome and dome-cavity pistons at an
engine speed of 1000 rev/min., using particle image velocimetry.
From the two-dimensional in-cylinder flow measurements, tumble
flow analysis is carried out in the combustion space on a vertical
plane passing through cylinder axis. To analyze the tumble flows,
ensemble average velocity vectors are used and to characterize it,
tumble ratio is estimated. From the results, generally, we have found
that tumble ratio varies mainly with crank angle position. Also, at the
end of compression stroke, average turbulent kinetic energy is more
at higher engine speeds. We have also found that, at 330 crank angle
position, flat piston shows an improvement of about 85 and 23% in
tumble ratio, and about 24 and 2.5% in average turbulent kinetic
energy compared to dome and dome-cavity pistons respectively
Abstract: A study concerning the photocatalytic decolourization
of Congo red (CR) dye, over artificial UV irradiation is presented.
Photocatalysts based on a commercial titanium dioxide (TiO2)
modified with transition metals (Ni, Cu and Zn) were used. The
dopage method used was wet impregnation. A TiO2 sample without
salt was subjected to the same hydrothermal treatment to be used as
reference. Congo red solutions to several pH conditions (natural and
basic) were used to evaluate photocatalytic performance of each
doped catalysts. Photodecolourization percentage was measured
spectrofotrometically after 3 h of treatment to 499 nm as response
variable. Kinetics investigations of photodegradation indicated that
reactions obey to Langmuir-Hinshelwood model and pseudo–first
order law. The rate constant studies of photocatalytic decolourization
reactions for Zn–TiO2 and Cu–TiO2 photocatalysts indicated that in
all cases the rate constant of the reaction was higher than that of TiO2
undoped. These results show that nature of the metal modifying the
TiO2 influence on the efficiency of the photocatalyst evaluated in
process. Ni does not present an additional effect compared with TiO2,
while Zn enhances the photoactivity due to its electronic properties.
Abstract: In this study, cometabolic biodegradation of
chloroform was experimented with mixed cultures in the presence of
various organic solvents like methanol, ethanol, isopropanol, acetone,
acetonitrile and toluene as these are predominant discharges in
pharmaceutical industries. Toluene and acetone showed higher
specific chloroform degradation rate when compared to other
compounds. Cometabolic degradation of chloroform was further
confirmed by observation of free chloride ions in the medium. An
extended Haldane model, incorporating the inhibition due to
chloroform and the competitive inhibition between primary
substrates, was developed to predict the biodegradation of primary
substrates, cometabolic degradation of chloroform and the biomass
growth. The proposed model is based on the use of biokinetic
parameters obtained from single substrate degradation studies. The
model was able to satisfactorily predict the experimental results of
ternary and quaternary mixtures. The proposed model can be used for
predicting the performance of bioreactors treating discharges from
pharmaceutical industries.
Abstract: Due to the dynamic nature of the Cloud, continuous monitoring of QoS requirements is necessary to manage the Cloud computing environment. The process of QoS monitoring and SLA violation detection consists of: collecting low and high level information pertinent to the service, analyzing the collected information, and taking corrective actions when SLA violations are detected. In this paper, we detail the architecture and the implementation of the first step of this process. More specifically, we propose an event-based approach to obtain run time information of services developed as BPEL processes. By catching particular events (i.e., the low level information), our approach recognizes the run-time execution path of a monitored service and uses the BPEL execution patterns to compute QoS of the composite service (i.e., the high level information).