Abstract: A mathematical model of the additional effects of the
liquid in the hydrodynamic gap is presented in the paper. An
incompressible viscous fluid is considered. Based on computational
modeling are determined the matrices of mass, stiffness and damping.
The mathematical model is experimentally verified.
Abstract: OPEN_EmoRec_II is an open multimodal corpus with
experimentally induced emotions. In the first half of the experiment,
emotions were induced with standardized picture material and in the
second half during a human-computer interaction (HCI), realized
with a wizard-of-oz design. The induced emotions are based on the
dimensional theory of emotions (valence, arousal and dominance).
These emotional sequences - recorded with multimodal data (facial
reactions, speech, audio and physiological reactions) during a
naturalistic-like HCI-environment one can improve classification
methods on a multimodal level.
This database is the result of an HCI-experiment, for which 30
subjects in total agreed to a publication of their data including the
video material for research purposes*. The now available open
corpus contains sensory signal of: video, audio, physiology (SCL,
respiration, BVP, EMG Corrugator supercilii, EMG Zygomaticus
Major) and facial reactions annotations.
Abstract: OPEN_EmoRec_II is an open multimodal corpus with
experimentally induced emotions. In the first half of the experiment,
emotions were induced with standardized picture material and in the
second half during a human-computer interaction (HCI), realized
with a wizard-of-oz design. The induced emotions are based on the
dimensional theory of emotions (valence, arousal and dominance).
These emotional sequences - recorded with multimodal data (facial
reactions, speech, audio and physiological reactions) during a
naturalistic-like HCI-environment one can improve classification
methods on a multimodal level.
This database is the result of an HCI-experiment, for which 30
subjects in total agreed to a publication of their data including the
video material for research purposes*. The now available open
corpus contains sensory signal of: video, audio, physiology (SCL,
respiration, BVP, EMG Corrugator supercilii, EMG Zygomaticus
Major) and facial reactions annotations.
Abstract: An experimental and analytical research on shear
buckling of a comparably large polymer composite I-section is
presented. It is known that shear buckling load of a large span
composite beam is difficult to determine experimentally. In order to
sensitively detect shear buckling of the tested I-section, twenty strain
rosettes and eight displacement sensors were applied and attached on
the web and flange surfaces. The tested specimen was a pultruded
composite beam made of vinylester resin, E-glass, carbon fibers and
micro-fillers. Various coupon tests were performed before the shear
buckling test to obtain fundamental material properties of the Isection.
An asymmetric four-point bending loading scheme was
utilized for the shear test. The loading scheme resulted in a high shear
and almost zero moment condition at the center of the web panel. The
shear buckling load was successfully determined after analyzing the
obtained test data from strain rosettes and displacement sensors. An
analytical approach was also performed to verify the experimental
results and to support the discussed experimental program.
Abstract: An Australian manufacturer has fabricated an
innovative GFRP sandwich panel made from E-glass fiber skin and a
modified phenolic core for structural applications. Debonding, which
refers to separation of skin from the core material in composite
sandwiches, is one of the most common types of damage in
composites. The presence of debonding is of great concern because it
not only severely affects the stiffness but also modifies the dynamic
behaviour of the structure. Generally it is seen that the majority of
research carried out has been concerned about the delamination of
laminated structures whereas skin-core debonding has received
relatively minor attention. Furthermore it is observed that research
done on composite slabs having multiple skin-core debonding is very
limited. To address this gap, a comprehensive research investigating
dynamic behaviour of composite panels with single and multiple
debonding is presented. The study uses finite-element modelling and
analyses for investigating the influence of debonding on free
vibration behaviour of single and multilayer composite sandwich
panels. A broad parametric investigation has been carried out by
varying debonding locations, debonding sizes and support conditions
of the panels in view of both single and multiple debonding.
Numerical models were developed with Strand7 finite element
package by innovatively selecting the suitable elements to diligently
represent their actual behavior. Three-dimensional finite element
models were employed to simulate the physically real situation as
close as possible, with the use of an experimentally and numerically
validated finite element model. Comparative results and conclusions
based on the analyses are presented. For similar extents and locations
of debonding, the effect of debonding on natural frequencies appears
greatly dependent on the end conditions of the panel, giving greater
decrease in natural frequency when the panels are more restrained.
Some modes are more sensitive to debonding and this sensitivity
seems to be related to their vibration mode shapes. The fundamental
mode seems generally the least sensitive mode to debonding with
respect to the variation in free vibration characteristics. The results
indicate the effectiveness of the developed three dimensional finite
element models in assessing debonding damage in composite
sandwich panels.
Abstract: Incineration of municipal solid waste (MSW) is one of
the key scopes in the global clean energy strategy. A computational
fluid dynamics (CFD) model was established in order to reveal these
features of the combustion process in a fixed porous bed of MSW.
Transporting equations and process rate equations of the waste bed
were modeled and set up to describe the incineration process,
according to the local thermal conditions and waste property
characters. Gas phase turbulence was modeled using k-ε turbulent
model and the particle phase was modeled using the kinetic theory of
granular flow. The heterogeneous reaction rates were determined
using Arrhenius eddy dissipation and the Arrhenius-diffusion
reaction rates. The effects of primary air flow rate and temperature in
the burning process of simulated MSW are investigated
experimentally and numerically. The simulation results in bed are
accordant with experimental data well. The model provides detailed
information on burning processes in the fixed bed, which is otherwise
very difficult to obtain by conventional experimental techniques.
Abstract: The dissimilar joint between aluminum/titanium
alloys (Al 6082 and Ti G2) were successfully achieved by CO2 laser
welding with a single pass and without filler material using the
overlap joint design. Laser welding parameters ranges combinations
were experimentally determined using Taguchi approach with the
objective of producing welded joint with acceptable welding profile
and high quality of mechanical properties. In this study a joining of
dissimilar Al 6082 / Ti G2 was resulted in three distinct regions
fusion area in the weldment. These regions are studied in terms of its
microstructural characteristics and microhardness which are directly
affecting the welding quality.
The weld metal was mainly composed of martensite alpha prime.
In two different metals in the two different sides of joint HAZ, grain
growth was detected. The microhardness of the joint distribution also
has shown microhardness increasing in the HAZ of two base metals
and a varying microhardness in fusion zone.
Abstract: The characteristics of temperature distribution and
electric field in a natural rubber glove (NRG) using microwave
energy during microwave heating process are investigated
numerically and experimentally. A three-dimensional model of NRG
and microwave oven are considered in this work. The influences of
position, heating time and rotation angle of NRG on temperature
distribution and electric field are presented in details. The coupled
equations of electromagnetic wave propagation and heat transfer are
solved using the finite element method (FEM). The numerical model
is validated with an experimental study at a frequency of 2.45 GHz.
The results show that the numerical results closely match the
experimental results. Furthermore, it is found that the temperature
distribution and electric field increases with increasing heating time.
The hot spot zone appears in NRG at the tip of middle finger while
the maximum temperature occurs in case of rotation angle of NRG =
60 degree. This investigation provides the essential aspects for a
fundamental understanding of heat transport of NRG using
microwave energy in industry.
Abstract: The composite pavement system considered in this
paper is composed of a functional surface layer, a fiber reinforced
asphalt middle layer and a fiber reinforced lean concrete base layer.
The mix design of the fiber reinforced lean concrete corresponds to the
mix composition of conventional lean concrete but reinforced by
fibers. The quasi-absence of research on the durability or long-term
performances (fatigue, creep, etc.) of such mix design stresses the
necessity to evaluate experimentally the long-term characteristics of
this layer composition. This study tests the creep characteristics as one
of the long-term characteristics of the fiber reinforced lean concrete
layer for composite pavement using a new creep device. The test
results reveal that the lean concrete mixed with fiber reinforcement
and fly ash develops smaller creep than the conventional lean
concrete. The results of the application of the CEB-FIP prediction
equation indicate that a modified creep prediction equation should be
developed to fit with the new mix design of the layer.
Abstract: Experimental & numeral study of temperature
distribution during milling process, is important in milling quality
and tools life aspects. In the present study the milling cross-section
temperature is determined by using Artificial Neural Networks
(ANN) according to the temperature of certain points of the work
piece and the point specifications and the milling rotational speed of
the blade. In the present work, at first three-dimensional model of the
work piece is provided and then by using the Computational Heat
Transfer (CHT) simulations, temperature in different nods of the
work piece are specified in steady-state conditions. Results obtained
from CHT are used for training and testing the ANN approach. Using
reverse engineering and setting the desired x, y, z and the milling
rotational speed of the blade as input data to the network, the milling
surface temperature determined by neural network is presented as
output data. The desired points temperature for different milling
blade rotational speed are obtained experimentally and by
extrapolation method for the milling surface temperature is obtained
and a comparison is performed among the soft programming ANN,
CHT results and experimental data and it is observed that ANN soft
programming code can be used more efficiently to determine the
temperature in a milling process.
Abstract: Fluid viscous damping systems are well suited for
many air vehicles subjected to shock and vibration. These damping
system work with the principle of viscous fluid throttling through the
orifice to create huge pressure difference between compression and
rebound chamber and obtain the required damping force. One
application of such systems is its use in aircraft door system to
counteract the door’s velocity and safely stop it. In exigency
situations like crash or emergency landing where the door doesn’t
open easily, possibly due to unusually tilting of fuselage or some
obstacles or intrusion of debris obstruction to move the parts of the
door, such system can be combined with other systems to provide
needed force to forcefully open the door and also securely stop it
simultaneously within the required time i.e. less than 8 seconds. In
the present study, a hydraulic system called snubber along with other
systems like actuator, gas bottle assembly which together known as
emergency power assist system (EPAS) is designed, built and
experimentally studied to check the magnitude of angular velocity,
damping force and time required to effectively open the door.
Whenever needed, the gas pressure from the bottle is released to
actuate the actuator and at the same time pull the snubber’s piston to
operate the emergency opening of the door. Such EPAS installed in
the suspension arm of the aircraft door is studied explicitly changing
parameters like orifice size, oil level, oil viscosity and bypass valve
gap and its spring of the snubber at varying temperature to generate
the optimum design case. Comparative analysis of the EPAS at
several cases is done and conclusions are made. It is found that
during emergency condition, the system opening time and angular
velocity, when snubber with 0.3mm piston and shaft orifice and
bypass valve gap of 0.5 mm with its original spring is used, shows
significant improvement over the old ones.
Abstract: It has experimentally been proved that the
performance of compression ignition (C.I.) engine is spray
characteristics related. In modern diesel engine the spray formation
and the eventual combustion process are the vital processes that offer
more challenges towards enhancing the engine performance. In the
present work the numerical simulation has been carried out for
evaporating diesel sprays using Fluent software. For computational
fluid dynamics simulation “Meshing” is done using Gambit software
before transmitting it into Fluent. The simulation is carried out using
hot bomb conditions under varying chamber conditions such as gas
pressure, nozzle diameter and fuel injection pressure. For comparison
purpose, the numerical simulations the chamber conditions were kept
the same as that of the experimental data. At varying chamber
conditions the spray penetration rates are compared with the existing
experimental results.
Abstract: Negative pressure phenomenon appears in many
thermodynamic, geophysical and biophysical processes in the Nature
and technological systems. For more than 100 years of the laboratory
researches beginning from F. M. Donny’s tests, the great values of
negative pressure have been achieved. But this phenomenon has not
been practically applied, being only a nice lab toy due to the special
demands for the purity and homogeneity of the liquids for its
appearance. The possibility of creation of direct wave of negative
pressure in real heterogeneous liquid systems was confirmed
experimentally under the certain kinetic and hydraulic conditions.
The negative pressure can be considered as the factor of both useful
and destroying energies. The new approach to generation of the
negative pressure waves in impure, unclean fluids has allowed the
creation of principally new energy saving technologies and
installations to increase the effectiveness and efficiency of different
production processes. It was proved that the negative pressure is one
of the main factors causing hard troubles in some technological and
natural processes. Received results emphasize the necessity to take
into account the role of the negative pressure as an energy factor in
evaluation of many transient thermohydrodynamic processes in the
Nature and production systems.
Abstract: In order to better understand the long term
implications of the grout wear failure mode in large-diameter plainsided
grouted connections, a numerical model has been developed
and calibrated that can take advantage of existing operational plant
data to predict the wear accumulation for the actual load conditions
experienced over a given period, thus limiting the requirement for
expensive monitoring systems. This model has been derived and
calibrated based on site structural condition monitoring (SCM) data
and supervisory control and data acquisition systems (SCADA) data
for two operational wind turbine generator substructures afflicted
with this challenge, along with experimentally derived wear rates.
Abstract: The design, manufacture, and operation of thin-walled
pressure vessels must be based on maximum safe operating pressure
and an adequate factor of safety (FoS). This research paper first
reports experimental evaluation of longitudinal and hoops stresses
based on working pressure as well as maximum pressure; and then
includes a critical study of factor of safety (FoS) in the design of a
glass fiber pressure vessel. Experimental work involved the use of
measuring instruments and the readings from pressure gauges.
Design calculations involved the computations of design stress and
FoS; the latter was based on breaking strength of 55 MPa for the
glass fiber (pressure-vessel material). The experimentally determined
FoS value has been critically compared with the general FoS allowed
in the design of glass fiber pressure vessels.
Abstract: Over the last few decades, oilfield service rolling
equipment has significantly increased in weight, primarily because of
emissions regulations, which require larger/heavier engines, larger
cooling systems, and emissions after-treatment systems, in some
cases, etc. Larger engines cause more vibration and shock loads,
leading to failure of electronics and control systems.
If the vibrating frequency of the engine matches the system
frequency, high resonance is observed on structural parts and mounts.
One such existing automated control equipment system comprising
wire rope mounts used for mounting computers was designed
approximately 12 years ago. This includes the use of an industrialgrade
computer to control the system operation. The original
computer had a smaller, lighter enclosure. After a few years, a newer
computer version was introduced, which was 10 lbm heavier. Some
failures of internal computer parts have been documented for cases in
which the old mounts were used. Because of the added weight, there
is a possibility of having the two brackets impact each other under
off-road conditions, which causes a high shock input to the computer
parts. This added failure mode requires validating the existing mount
design to suit the new heavy-weight computer.
This paper discusses the modal finite element method (FEM)
analysis and experimental modal analysis conducted to study the
effects of vibration on the wire rope mounts and the computer. The
existing mount was modelled in ANSYS software, and resultant
mode shapes and frequencies were obtained. The experimental modal
analysis was conducted, and actual frequency responses were
observed and recorded.
Results clearly revealed that at resonance frequency, the brackets
were colliding and potentially causing damage to computer parts. To
solve this issue, spring mounts of different stiffness were modeled in
ANSYS software, and the resonant frequency was determined.
Increasing the stiffness of the system increased the resonant
frequency zone away from the frequency window at which the engine
showed heavy vibrations or resonance. After multiple iterations in
ANSYS software, the stiffness of the spring mount was finalized,
which was again experimentally validated.
Abstract: The recommended limit for cadmium concentration in
potable water is less than 0.005 mg/L. A continuous biosorption
process using indigenous red seaweed, Gracilaria corticata, was
performed to remove cadmium from the potable water. The process
was conducted under fixed conditions and the breakthrough curves
were achieved for three consecutive sorption-desorption cycles. A
modeling based on Artificial Neural Network (ANN) was employed
to fit the experimental breakthrough data. In addition, a simplified
semi empirical model, Thomas, was employed for this purpose. It
was found that ANN well described the experimental data (R2>0.99)
while the Thomas prediction were a bit less successful with R2>0.97.
The adjusted design parameters using the nonlinear form of Thomas
model was in a good agreement with the experimentally obtained
ones. The results approve the capability of ANN to predict the
cadmium concentration in potable water.
Abstract: Solar air heater is a type of heat exchanger which
transforms solar radiation into heat energy. The thermal performance
of conventional solar air heater has been found to be poor because of
the low convective heat transfer coefficient from the absorber plate to
the air. It is attributed to the formation of a very thin boundary layer
at the absorber plate surface commonly known as viscous sub-layer.
Thermal efficiency of solar air heater can be improved by providing
the artificial roughness on absorber plate is the most efficient
technique. In this paper an attempt is made to provide artificial
roughness by incorporating inclined multiple V-ribs in the underside
of the absorber plate. 60˚V – ribs are arranged inclined to the
direction of air flow. Performance of collector estimated theoretically
and experimentally. Results of the investigation reveal that thermal
efficiency of collector with multiple V-ribs increased by 14%.
Abstract: The effect of a 3-dimensional (3D) blade on the turbine
characteristics of Wells turbine for wave energy conversion has been
investigated experimentally by model testing under steady flow
conditions in this study, in order to improve the peak efficiency and
stall characteristics. The aim of use of 3D blade is to prevent flow
separation on the suction surface near the tip. The chord length is
constant with radius and the blade profile changes gradually from the
mean radius to tip. The proposed blade profiles in the study are
NACA0015 from the hub to mean radius and NACA0025 at the tip.
The performances of Wells turbine with 3D blades has been compared
with those of the original Wells turbine, i.e., the turbine with
2-dimensional (2D) blades. As a result, it was concluded that although
the peak efficiency of Wells turbine can be improved by the use of the
proposed 3D blade, its blade does not overcome the weakness of
stalling.
Abstract: Vacuum insulation panel (VIP) is a promising thermal
insulator for buildings, refrigerator, LNG carrier and so on. In general,
it has the thermal conductivity of 2~4 mW/m·K. However, this thermal
conductivity is that measured at the center of VIP. The total effective
thermal conductivity of VIP is larger than this value due to the edge
conduction through the envelope. In this paper, the edge conduction of
VIP is examined theoretically, numerically and experimentally. To
confirm the existence of the edge conduction, numerical analysis is
performed for simple two-dimensional VIP model and a theoretical
model is proposed to calculate the edge conductivity. Also, the edge
conductivity is measured using the vacuum guarded hot plate and the
experiment is validated against numerical analysis. The results show
that the edge conductivity is dependent on the width of panel and
thickness of Al-foil. To reduce the edge conduction, it is recommended
that the VIP should be made as big as possible or made of thin Al film
envelope.