Abstract: Method of combined teaching laws of classical
mechanics and hydrostatics in non-inertial reference frames for
undergraduate students is proposed. Pressure distribution in a liquid
(or gas) moving with acceleration is considered. Combined effect of
hydrostatic force and force of inertia on a body immersed in a liquid
can lead to paradoxical results, in a motion of pendulum in particular.
The body motion under Stokes force influence and forces in rotating
reference frames are investigated as well. Problems and difficulties in
student perceptions are analyzed.
Abstract: In this paper comprehensive studies have been carried
out for the design optimization of a waste heat recovery system for
effectively utilizing the domestic air conditioner heat energy for
producing hot water. Numerical studies have been carried for the
geometry optimization of a waste heat recovery system for domestic
air conditioners. Numerical computations have been carried out using
a validated 2d pressure based, unsteady, 2nd-order implicit, SST k-ω
turbulence model. In the numerical study, a fully implicit finite
volume scheme of the compressible, Reynolds-Averaged, Navier-
Stokes equations is employed. At identical inflow and boundary
conditions various geometries were tried and effort has been taken for
proposing the best design criteria. Several combinations of pipe line
shapes viz., straight and spiral with different number of coils for the
radiator have been attempted and accordingly the design criteria has
been proposed for the waste heat recovery system design. We have
concluded that, within the given envelope, the geometry optimization
is a meaningful objective for getting better performance of waste heat
recovery system for air conditioners.
Abstract: The use of titanium fluoride and iron fluoride
(TiF3/FeF3) catalysts in combination with polutetrafluoroethylene
(PTFE) in plain zinc- dialkyldithiophosphate (ZDDP) oil is important
for the study of engine tribocomponents and is increasingly a strategy
to improve the formation of tribofilm and provide low friction and
excellent wear protection in reduced phosphorus plain ZDDP oil. The
influence of surface roughness and the concentration of
TiF3/FeF3/PTFE were investigated using bearing steel samples
dipped in lubricant solution at 100°C for two different heating time
durations. This paper addresses the effects of water drop contact
angle using different surface; finishes after treating them with
different lubricant combination. The calculated water drop contact
angles were analyzed using Design of Experiment software (DOE)
and it was determined that a 0.05 μm Ra surface roughness would
provide an excellent TiF3/FeF3/PTFE coating for antiwear resistance
as reflected in the Scanning electron microscopy (SEM) images and
the tribological testing under extreme pressure conditions. Both
friction and wear performance depend greatly on the PTFE/and
catalysts in plain ZDDP oil with 0.05 % phosphorous and on the
surface finish of bearing steel. The friction and wear reducing effects,
which was observed in the tribological tests, indicated a better micro
lubrication effect of the 0.05 μm Ra surface roughness treated at
100°C for 24 hours when compared to the 0.1 μm Ra surface
roughness with the same treatment.
Abstract: Nine Degrees of Freedom (9 DOF) systems are
already in development in many areas. In this paper, an integrated
pressure sensor is proposed that will make use of an already existing
monolithic 9 DOF inertial MEMS platform. Capacitive pressure
sensors can suffer from limited sensitivity for a given size of
membrane. This novel pressure sensor design increases the sensitivity
by over 5 times compared to a traditional array of square diaphragms
while still fitting within a 2 mm x 2 mm chip and maintaining a fixed
static capacitance. The improved design uses one large diaphragm
supported by pillars with fixed electrodes placed above the areas of
maximum deflection. The design optimization increases the
sensitivity from 0.22 fF/kPa to 1.16 fF/kPa. Temperature sensitivity
was also examined through simulation.
Abstract: Chalcopyrite (CuFeS2) is the most common primary
mineral used for the commercial production of copper. The low
dissolution efficiency of chalcopyrite in sulfate media has prevented
an efficient industrial leaching of this mineral in sulfate media. Ferric
ions, bacteria, oxygen and other oxidants have been used as oxidizing
agents in the leaching of chalcopyrite in sulfate and chloride media
under atmospheric or pressure leaching conditions. Two leaching
methods were studied to evaluate chalcopyrite (CuFeS2) dissolution
in acid media. First, the conventional oxidative acid leaching method
was carried out using sulfuric acid (H2SO4) and potassium
dichromate (K2Cr2O7) as oxidant at atmospheric pressure. Second,
microwave-assisted acid leaching was performed using the
microwave accelerated reaction system (MARS) for same reaction
media. Parameters affecting the copper extraction such as leaching
time, leaching temperature, concentration of H2SO4 and
concentration of K2Cr2O7 were investigated. The results of
conventional acid leaching experiments were compared to the
microwave leaching method. It was found that the copper extraction
obtained under high temperature and high concentrations of oxidant
with microwave leaching is higher than those obtained
conventionally. 81% copper extraction was obtained by the
conventional oxidative acid leaching method in 180 min, with the
concentration of 0.3 mol/L K2Cr2O7 in 0.5M H2SO4 at 50 ºC, while
93.5% copper extraction was obtained in 60 min with microwave
leaching method under same conditions.
Abstract: The design of Reverse logistics Network has attracted
growing attention with the stringent pressures from both
environmental awareness and business sustainability. Reverse
logistical activities include return, remanufacture, disassemble and
dispose of products can be quite complex to manage. In addition,
demand can be difficult to predict, and decision making is one of the
challenges task in such network. This complexity has amplified the
need to develop an integrated architecture for product return as an
enterprise system. The main purpose of this paper is to design Multi
Agent System (MAS) architecture using the Prometheus
methodology to efficiently manage reverse logistics processes. The
proposed MAS architecture includes five types of agents: Gate
keeping Agent, Collection Agent, Sorting Agent, Processing Agent
and Disposal Agent which act respectively during the five steps of
reverse logistics Network.
Abstract: Phonocardiography is important in appraisal of
congenital heart disease and pulmonary hypertension as it reflects the
duration of right ventricular systoles. The systolic murmur in patients
with intra-cardiac shunt decreases as pulmonary hypertension
develops and may eventually disappear completely as the pulmonary
pressure reaches systemic level. Phonocardiography and auscultation
are non-invasive, low-cost, and accurate methods to assess heart
disease. In this work an objective signal processing tool to extract
information from phonocardiography signal using Wavelet is
proposed to classify the murmur as normal or abnormal. Since the
feature vector is large, a Binary Particle Swarm Optimization (PSO)
with mutation for feature selection is proposed. The extracted
features improve the classification accuracy and were tested across
various classifiers including Naïve Bayes, kNN, C4.5, and SVM.
Abstract: The MEMS pressure sensor has been introduced and
presented in this paper. The types of pressure sensor and its theory of
operation are also included. The latest MEMS technology, the
fabrication processes of pressure sensor are explored and discussed.
Besides, various device applications of pressure sensor such as tire
pressure-monitoring system, diesel particulate filter and others are
explained. Due to further miniaturization of the device nowadays, the
pressure sensor with nanotechnology (NEMS) is also reviewed. The
NEMS pressure sensor is expected to have better performance as well
as lower in its cost. It has gained an excellent popularity in many
applications.
Abstract: The design of high pressure water jet based polishing
equipment and its fabrication conducted in this study is reported
herein, together with some preliminary test results for assessing its
applicability for HMA surface polishing. This study also provides
preliminary findings concerning the test variables, such as the
rotational speed, the water jet pressure, the abrasive agent used, and
the impact angel that were experimentally investigated in this study. The preliminary findings based on four trial tests (two on large
slab specimens and two on small size gyratory compacted
specimens), however, indicate that both friction and texture values
tend to increase with the polishing durations for two combinations of
pressure and rotation speed of the rotary deck. It seems that the more
polishing action the specimen is subjected to; the aggregate edges are
created such that the surface texture values are increased with the
accompanied increase in friction values. It may be of interest (but
which is outside the scope of this study) to investigate if the similar
trend exist for HMA prepared with aggregate source that is sand and
gravel.
Abstract: Distillery spentwash contains high chemical oxygen
demand (COD), biological oxygen demand (BOD), color, total
dissolved solids (TDS) and other contaminants even after biological
treatment. The effluent can’t be discharged as such in the surface
water bodies or land without further treatment. Reverse osmosis (RO)
treatment plants have been installed in many of the distilleries at
tertiary level in many of the distilleries in India, but are not properly
working due to fouling problem which is caused by the presence of
high concentration of organic matter and other contaminants in
biologically treated spentwash. In order to make the membrane
treatment a proven and reliable technology, proper pre-treatment is
mandatory. In the present study, ultra-filtration (UF) for pretreatment
of RO at tertiary stage has been performed. Operating
parameters namely initial pH (pHo: 2–10), trans-membrane pressure
(TMP: 4-20 bars) and temperature (T: 15-43°C) were used for
conducting experiments with UF system. Experiments were
optimized at different operating parameters in terms of COD, color,
TDS and TOC removal by using response surface methodology
(RSM) with central composite design. The results showed that
removal of COD, color and TDS was 62%, 93.5% and 75.5%
respectively, with UF, at optimized conditions with increased
permeate flux from 17.5 l/m2/h (RO) to 38 l/m2/h (UF-RO). The
performance of the RO system was greatly improved both in term of
pollutant removal as well as water recovery.
Abstract: Biodiesel production from vegetable oil will produce
glycerol as by-product about 10% of the biodiesel production. The
amount of glycerol that was produced needed alternative way to
handling immediately so as to not become the waste that polluted
environment. One of the solutions was to process glycerol to
polyglycidyl nitrate (PGN). PGN is synthesized from glycerol by
three-step reactions i.e. nitration of glycerol, cyclization of 13-
dinitroglycerine and polymerization of glycosyl nitrate. Optimum
condition of nitration of glycerol with nitric acid has not been known.
Thermodynamic feasibility should be done before run experiments in
the laboratory. The aim of this study was to determine the parameters
those affect nitration of glycerol and nitric acid and chose the
operation condition. Many parameters were simulated to verify its
possibility to experiment under conditions which would get the
highest conversion of 1, 3-dinitroglycerine and which was the ideal
condition to get it. The parameters that need to be studied to obtain
the highest conversion of 1, 3-dinitroglycerine were mol ratio of
nitric acid/glycerol, reaction temperature, mol ratio of
glycerol/dichloromethane and pressure. The highest conversion was
obtained in the range of mol ratio of nitric acid /glycerol between 2/1
– 5/1, reaction temperature of 5-25oC and pressure of 1 atm. The
parameters that need to be studied further to obtain the highest
conversion of 1.3 DNG are mol ratio of nitric acid/glycerol and
reaction temperature.
Abstract: This paper describes a novel sensor device, a pressure
pulse wave meter, which uses a bidirectional condenser microphone.
The microphone work as a microphone as well as a sensor with high
gain over a wide frequency range; they are also highly reliable and
economic. Currently aging is becoming a serious social issue in Japan causing
increased medical expenses in the country. Hence, it is important for
elderly citizens to check health condition at home, and to care the
health conditions through daily monitoring. Given this circumstances,
we developed a novel pressure pulse wave meter based on a
bidirectional condenser microphone: this device is used as a measuring
instrument of health conditions.
Abstract: The work aims to develop a robot in the form of
autonomous vehicle to detect, inspection and mapping of
underground pipelines through the ATmega328 Arduino platform.
Hardware prototyping is very similar to C / C ++ language that
facilitates its use in robotics open source, resembles PLC used in
large industrial processes. The robot will traverse the surface
independently of direct human action, in order to automate the
process of detecting buried pipes, guided by electromagnetic
induction. The induction comes from coils that send the signal to the
Arduino microcontroller contained in that will make the difference in
intensity and the treatment of the information, and then this
determines actions to electrical components such as relays and
motors, allowing the prototype to move on the surface and getting the
necessary information. This change of direction is performed by a
stepper motor with a servo motor. The robot was developed by
electrical and electronic assemblies that allowed test your application.
The assembly is made up of metal detector coils, circuit boards and
microprocessor, which interconnected circuits previously developed
can determine, process control and mechanical actions for a robot
(autonomous car) that will make the detection and mapping of buried
pipelines plates. This type of prototype can prevent and identifies
possible landslides and they can prevent the buried pipelines suffer an
external pressure on the walls with the possibility of oil leakage and
thus pollute the environment.
Abstract: This paper presents the design and fabrication of a
novel piezoelectric actuator for a gas micro pump with check valve
having the advantages of miniature size, light weight and low power
consumption. The micro pump is designed to have eight major
components, namely a stainless steel upper cover layer, a piezoelectric
actuator, a stainless steel diaphragm, a PDMS chamber layer, two
stainless steel channel layers with two valve seats, a PDMS check
valve layer with two cantilever-type check valves and an acrylic
substrate. A prototype of the gas micro pump, with a size of 52 mm ×
50 mm × 5.0 mm, is fabricated by precise manufacturing. This device
is designed to pump gases with the capability of performing the
self-priming and bubble-tolerant work mode by maximizing the stroke
volume of the membrane as well as the compression ratio via
minimization of the dead volume of the micro pump chamber and
channel. By experiment apparatus setup, we can get the real-time
values of the flow rate of micro pump and the displacement of the
piezoelectric actuator, simultaneously. The gas micro pump obtained
higher output performance under the sinusoidal waveform of 250 Vpp.
The micro pump achieved the maximum pumping rates of 1185
ml/min and back pressure of 7.14 kPa at the corresponding frequency
of 120 and 50 Hz.
Abstract: Effect of sprue/metal head height on mould filling,
microstructure and mechanical properties of TWDI casting is studied.
Results show that metal/sprue height of 50 mm is not sufficient to
push the melt through the gating channel, but as it is increased from
100-350 mm, proper mould filling is achieved. However at higher
heights between 200 mm and 350 mm, defects associated with
incomplete solidification, carbide precipitation and turbulent flow are
evident. This research shows that superior UTS, hardness, nodularity
and nodule count are obtained at 100 mm sprue height.
Abstract: Dynamics of a rotor supported by air bearings is
strongly depends on the pressure distribution between the rotor and
the bearing. In this study, internal pressure in air bearings is
numerical and experimental analyzed for different radial clearances.
Firstly the pressure distribution between rotor and bearing is modeled
using Reynold's equation and this model is solved numerically. The
rotor-bearing system is also modeled in four degree of freedom and it
is simulated for different radial clearances. Then, in order to validate
numerical results, a test rig is designed and the rotor bearing system
is run under the same operational conditions. Pressure signals of left
and right bearings are recorded. Internal pressure variations are
compared for numerical and experimental results for different radial
clearances.
Abstract: In this paper, we investigated the athermal pressure
behavior of the structural and elastic properties of scheelite BaWO4
phase up to 7 GPa using the ab initio pseudo-potential method. The
calculated lattice parameters pressure relation have been compared
with the experimental values and found to be in good agreement with
these results. Moreover, we present for the first time the investigation
of the elastic properties of this compound using the density functional
perturbation theory (DFPT). It is shown that this phase is
mechanically stable up to 7 GPa after analyzing the calculated elastic
constants. Other relevant quantities such as bulk modulus, pressure
derivative of bulk modulus, shear modulus; Young’s modulus,
Poisson’s ratio, anisotropy factors, Debye temperature and sound
velocity have been calculated. The obtained results, which are
reported for the first time to the best of the author’s knowledge, can
facilitate assessment of possible applications of the title material.
Abstract: The numerical simulation has made tremendous
advances in investigating the blood flow phenomenon through elastic
arteries. Such study can be useful in demonstrating the disease
progression and hemodynamics of cardiovascular diseases such as
atherosclerosis. In the present study, patient specific case diagnosed
with partially stenosed complete right ICA and normal left carotid
bifurcation without any atherosclerotic plaque formation is
considered. 3D patient specific carotid bifurcation model is generated
based on CT scan data using MIMICS-4.0 and numerical analysis is
performed using FSI solver in ANSYS-14.5. The blood flow is
assumed to be incompressible, homogenous and Newtonian, while
the artery wall is assumed to be linearly elastic. The two-way
sequentially coupled transient FSI analysis is performed using FSI
solver for three pulse cycles. The hemodynamic parameters such as
flow pattern, Wall Shear Stress, pressure contours and arterial wall
deformation are studied at the bifurcation and critical zones such as
stenosis. The variation in flow behavior is studied throughout the
pulse cycle. Also, the simulation results reveal that there is a
considerable increase in the flow behavior in stenosed carotid in
contrast to the normal carotid bifurcation system. The investigation
also demonstrates the disturbed flow pattern especially at the
bifurcation and stenosed zone elevating the hemodynamics,
particularly during peak systole and later part of the pulse cycle. The
results obtained agree well with the clinical observation and
demonstrates the potential of patient specific numerical studies in
prognosis of disease progression and plaque rupture.
Abstract: In this study, the experiments were carried out to
determine the best coolant for the quenching process among waterbased
silica, alumina, titania and copper oxide nanofluids (0.1 vol%).
A sphere made up off brass material was used in the experiments.
When the spherical test specimen was heated at high temperatures, it
was suddenly immersed into the nanofluids. All experiments were
carried out at saturated conditions and under atmospheric pressure.
After the experiments, the cooling curves were obtained by using the
temperature-time data of the specimen. The experimental results
showed that the cooling performance of test specimen depended on
the type of nanofluids. The silica nanoparticles enhanced the
performance of boiling heat transfer and it is the best coolant for the
quenching among other nanoparticles.
Abstract: Complex lifting entry was selected for precise landing
performance during the Mars Science Laboratory entry. This study
aims to develop the three-dimensional numerical method for precise
computation and the surface panel method for rapid engineering
prediction. Detailed flow field analysis for Mars exploration mission
was performed by carrying on a series of fully three-dimensional
Navier-Stokes computations. The static aerodynamic performance was
then discussed, including the surface pressure, lift and drag coefficient,
lift-to-drag ratio with the numerical and engineering method.
Computation results shown that the shock layer is thin because of
lower effective specific heat ratio, and that calculated results from both
methods agree well with each other, and is consistent with the
reference data. Aerodynamic performance analysis shows that CG
location determines trim characteristics and pitch stability, and certain
radially and axially shift of the CG location can alter the capsule lifting
entry performance, which is of vital significance for the aerodynamic
configuration design and inner instrument layout of the Mars entry
capsule.