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.
Abstract: In this paper we propose a computer-aided solution
with Genetic Algorithms in order to reduce the drafting of reports:
FMEA analysis and Control Plan required in the manufacture of the
product launch and improved knowledge development teams for
future projects. The solution allows to the design team to introduce
data entry required to FMEA. The actual analysis is performed using
Genetic Algorithms to find optimum between RPN risk factor and
cost of production. A feature of Genetic Algorithms is that they are
used as a means of finding solutions for multi criteria optimization
problems. In our case, along with three specific FMEA risk factors is
considered and reduce production cost. Analysis tool will generate
final reports for all FMEA processes. The data obtained in FMEA
reports are automatically integrated with other entered parameters in
Control Plan. Implementation of the solution is in the form of an
application running in an intranet on two servers: one containing
analysis and plan generation engine and the other containing the
database where the initial parameters and results are stored. The
results can then be used as starting solutions in the synthesis of other
projects. The solution was applied to welding processes, laser cutting
and bending to manufacture chassis for buses. Advantages of the
solution are efficient elaboration of documents in the current project
by automatically generating reports FMEA and Control Plan using
multiple criteria optimization of production and build a solid
knowledge base for future projects. The solution which we propose is
a cheap alternative to other solutions on the market using Open
Source tools in implementation.
Abstract: Knowledge of bone mechanical properties is important
for bone substitutes design and fabrication, and more efficient
prostheses development. The aim of this study is to characterize the
viscoelastic behavior of bone specimens, through stress relaxation
and fatigue tests performed to trabecular bone samples from bovine
femoral heads. Relaxation tests consisted on preloading the samples
at five different magnitudes and evaluate them for 1020 seconds,
adjusting the results to a KWW mathematical model. Fatigue tests
consisted of 700 load cycles and analyze their status at the end of the
tests. As a conclusion we have that between relaxation stress and
each preload there is linear relation and for samples with initial
Young´s modulus greater than 1.5 GPa showed no effects due fatigue
test loading cycles.
Abstract: In this paper, we are interested in the problem of
finding similar images in a large database. For this purpose we
propose a new algorithm based on a combination of the 2-D
histogram intersection in the HSV space and statistical moments. The
proposed histogram is based on a 3x3 window and not only on the
intensity of the pixel. This approach overcome the drawback of the
conventional 1-D histogram which is ignoring the spatial distribution
of pixels in the image, while the statistical moments are used to
escape the effects of the discretisation of the color space which is
intrinsic to the use of histograms. We compare the performance of
our new algorithm to various methods of the state of the art and we
show that it has several advantages. It is fast, consumes little memory
and requires no learning. To validate our results, we apply this
algorithm to search for similar images in different image databases.
Abstract: Biomass briquette gasification is regarded as a
promising route for efficient briquette use in energy generation, fuels
and other useful chemicals. However, previous research has been
focused on briquette gasification in fixed bed gasifiers such as
updraft and downdraft gasifiers. Fluidised bed gasifier has the
potential to be effectively sized to medium or large scale. This study
investigated the use of fuel briquettes produced from blends of rice
husks and corn cobs biomass, in a bubbling fluidised bed gasifier.
The study adopted a combination of numerical equations and Aspen
Plus simulation software, to predict the product gas (syngas)
composition base on briquette density and biomass composition
(blend ratio of rice husks to corn cobs). The Aspen Plus model was
based on an experimentally validated model from the literature. The
results based on a briquette size 32 mm diameter and relaxed density
range of 500 to 650kg/m3, indicated that fluidisation air required in
the gasifier increased with increase in briquette density, and the
fluidisation air showed to be the controlling factor compared with the
actual air required for gasification of the biomass briquettes. The
mass flowrate of CO2 in the predicted syngas composition increased
with an increase in air flow, in the gasifier, while CO decreased and
H2 was almost constant. The ratio of H2 to CO for various blends of
rice husks and corn cobs did not significantly change at the designed
process air, but a significant difference of 1.0 was observed between
10/90 and 90/10 % blend of rice husks and corn cobs.
Abstract: This study was aimed to investigate the machining
stability of a spindle tool with different preloaded amount. To this end,
the vibration tests were conducted on the spindle unit with different
preload to assess the dynamic characteristics and machining stability
of the milling machine. Current results demonstrate that the tool tip
frequency response characteristics and the machining stabilities in X
and Y direction are affected to change due to the different preload of
spindle bearings. As found from the results, a high preloaded spindle
tool shows higher limited cutting depth at mid position, while a spindle
with low preload shows a higher limited depth. This indicates that the
machining stability of a milling machine is affected to vary by the
spindle unit when it was assembled with different bearing preload.
Abstract: More than 3000 plants of notable phyto-therapeutic
value grow in South Africa; these include Cissampelos capensis,
commonly known in Afrikaans as dawidjie or dawidjiewortel. C.
capensis is the most significant and popular medicinal plant used by
the Khoisan as well as other rural groups in the Western region of
South Africa. Its rhizomes are traditionally used to treat male fertility
problems. Yet, no studies have investigated the effects of this plant or
its extracts on human spermatozoa. Therefore, this study aimed at
investigating the effects of C. capensis rhizome extract (CRE)
fractions on ejaculated human spermatozoa in vitro. Spermatozoa
from a total of 77 semen samples were washed with human tubular
fluid medium supplemented with bovine serum albumin (HTF-BSA)
and incubated for 2 hours with 20 μg/ml progesterone (P4) followed
by incubation with different concentrations (0, 0.05, 0.5, 5, 50, 200
μg/ml) of fractionated CRE (F1=0% MeOH, F2=30% MeOH,
F3=60% MeOH and F4=100% MeOH) for 1.5 hours at 37°C. A
sample without addition of CRE fractions served as control. Samples
were analyzed for sperm motility, reactive oxygen species (ROS),
DNA-fragmentation, acrosome reaction and capacitation. Results
showed that F1 resulted in significantly higher values for ROS,
capacitation and hyper-activation compared to F2, F3, and F4 with
P4-stimulated samples generally having higher values. No significant
effect was found for the other parameters. In conclusion, alkaloids
present in F1 of CRE appear to have triggered sperm intrinsic ROS
production leading to sperm capacitation and acrosome reaction
induced by P4.
Abstract: Steady three-dimensional and two free surface waves
generated by moving bodies are presented, the flow problem to be
simulated is rich in complexity and poses many modeling challenges
because of the existence of breaking waves around the ship hull, and
because of the interaction of the two-phase flow with the turbulent
boundary layer. The results of several simulations are reported. The
first study was performed for NACA0012 of hydrofoil with different
meshes, this section is analyzed at h/c= 1, 0345 for 2D. In the second
simulation a mathematically defined Wigley hull form is used to
investigate the application of a commercial CFD code in prediction of
the total resistance and its components from tangential and normal
forces on the hull wetted surface. The computed resistance and wave
profiles are used to estimate the coefficient of the total resistance for
Wigley hull advancing in calm water under steady conditions. The
commercial CFD software FLUENT version 12 is used for the
computations in the present study. The calculated grid is established
using the code computer GAMBIT 2.3.26. The shear stress k-ωSST
model is used for turbulence modeling and the volume of fluid
technique is employed to simulate the free-surface motion. The
second order upwind scheme is used for discretizing the convection
terms in the momentum transport equations, the Modified HRIC
scheme for VOF discretization. The results obtained compare well
with the experimental data.
Abstract: An investigation of adaptable winglets for enhancing
morphing aircraft performance is described in this paper. The
concepts investigated consist of various winglet configurations
fundamentally centered on a baseline swept wing. The impetus for
the work was to identify and optimize winglets to enhance the
aerodynamic efficiency of a morphing aircraft. All computations
were performed with Athena Vortex Lattice modelling with varying
degrees of twist and cant angle considered. The results from this
work indicate that if adaptable winglets were employed on aircraft’s
improvements in aircraft performance could be achieved.
Abstract: Aluminium matrix composites with alumina
reinforcements give superior mechanical & physical properties. Their
applications in several fields like automobile, aerospace, defense,
sports, electronics, bio-medical and other industrial purposes are
becoming essential for the last several decades. In the present work,
fabrication of hybrid composite was done by Stir casting technique
using Al 6061 as a matrix with alumina and silicon carbide (SiC) as
reinforcement materials. The weight percentage of alumina is varied
from 2 to 4% and the silicon carbide weight percentage is maintained
constant at 2%. Hardness and wear tests are performed in the as cast
and heat treated conditions. Age hardening treatment was performed
on the specimen with solutionizing at 550°C, aging at two
temperatures (150 and 200°C) for different time durations. Hardness
distribution curves are drawn and peak hardness values are recorded.
Hardness increase was very sensitive with respect to the decrease in
aging temperature. There was an improvement in wear resistance of
the peak aged material when aged at lower temperature. Also
increase in weight percent of alumina, increases wear resistance at
lower temperature but opposite behavior was seen when aged at
higher temperature.
Abstract: The present study was aimed to examine the structure
of children’s adaptation during school transition and to identify a
commonality and dissimilarity at the elementary and junior high
school. 1,983 students in the 6th grade and 2,051 students in the 7th
grade were extracted by stratified two-stage random sampling and
completed the ASSESS that evaluated the school adaptation from the
view point of ‘general satisfaction’, ‘teachers’ support’, ‘friends’
support’, ‘anti-bullying relationship’, ‘prosocial skills’, and ‘academic
adaptation’. The 7th graders tend to be worse adaptation than the 6th
graders. A structural equation modeling showed the goodness of fit for
each grades. Both models were very similar but the 7th graders’ model
showed a lower coefficient at the pass from ‘teachers’ support’ to
‘friends’ support’. The role of ‘teachers’ support’ was decreased to
keep a good relation in junior high school. We also discussed how we
provide a continuous assistance for prevention of the 7th graders’ gap.
Abstract: Steady three-dimensional and two free surface waves
generated by moving bodies are presented, the flow problem to be
simulated is rich in complexity and poses many modeling challenges
because of the existence of breaking waves around the ship hull, and
because of the interaction of the two-phase flow with the turbulent
boundary layer. The results of several simulations are reported. The
first study was performed for NACA0012 of hydrofoil with different
meshes, this section is analyzed at h/c= 1, 0345 for 2D. In the second
simulation a mathematically defined Wigley hull form is used to
investigate the application of a commercial CFD code in prediction of
the total resistance and its components from tangential and normal
forces on the hull wetted surface. The computed resistance and wave
profiles are used to estimate the coefficient of the total resistance for
Wigley hull advancing in calm water under steady conditions. The
commercial CFD software FLUENT version 12 is used for the
computations in the present study. The calculated grid is established
using the code computer GAMBIT 2.3.26. The shear stress k-ωSST
model is used for turbulence modeling and the volume of fluid
technique is employed to simulate the free-surface motion. The
second order upwind scheme is used for discretizing the convection
terms in the momentum transport equations, the Modified HRIC
scheme for VOF discretization. The results obtained compare well
with the experimental data.
Abstract: Fast speed drives for Permanent Magnet Synchronous
Motor (PMSM) is a crucial performance for the electric traction
systems. In this paper, PMSM is derived with a Model-based
Predictive Control (MPC) technique. Fast speed tracking is achieved
through optimization of the DC source utilization using MPC. The
technique is based on predicting the optimum voltage vector applied
to the driver. Control technique is investigated by comparing to the
cascaded PI control based on Space Vector Pulse Width Modulation
(SVPWM). MPC and SVPWM-based FOC are implemented with the
TMS320F2812 DSP and its power driver circuits. The designed MPC
for a PMSM drive is experimentally validated on a laboratory test
bench. The performances are compared with those obtained by a
conventional PI-based system in order to highlight the improvements,
especially regarding speed tracking response.
Abstract: To ensure targeting of apoferritin nanocarrier with
encapsulated doxorubicin drug, we used a peptide linker based on a
protein G with N-terminus affinity towards Fc region of antibodies.
To connect the peptide to the surface of apoferritin, the C-terminus of
peptide was made of cysteine with affinity to gold. The surface of
apoferritin with encapsulated doxorubicin (APODOX) was coated
either with gold nanoparticles (APODOX-Nano) or gold(III) chloride
hydrate reduced with sodium borohydride (APODOX-HAu). The
reduction with sodium borohydride caused a loss of doxorubicin
fluorescent properties and probably accompanied with the loss of its
biological activity. Fluorescent properties of APODOX-Nano were
similar to the unmodified APODOX; therefore it was more suited for
the intended use. To evaluate the specificity of apoferritin modified
with antibodies, ELISA-like method was used with the surface of
microtitration plate wells coated by the antigen (goat anti-human IgG
antibodies). To these wells, the nanocarrier was applied. APODOX
without the modification showed 5× lower affinity to the antigen than
APODOX-Nano modified gold and targeting antibodies (human IgG
antibodies).
Abstract: The novel 3D SnO cabbages self-assembled by
nanosheets were successfully synthesized via template-free
hydrothermal growth method under facile conditions. The XRD
results manifest that the as-prepared SnO is tetragonal phase. The
TEM and HRTEM results show that the cabbage nanosheets are
polycrystalline structure consisted of considerable single-crystalline
nanoparticles. Two typical Raman modes A1g=210 and Eg=112 cm-1
of SnO are observed by Raman spectroscopy. Moreover, galvanostatic
cycling tests has been performed using the SnO cabbages as anode
material of lithium ion battery and the electrochemical results suggest
that the synthesized SnO cabbage structures are a promising anode
material for lithium ion batteries.
Abstract: Current research is targeting new molecular
mechanisms that underlie non-alcoholic fatty liver disease (NAFLD)
and associated metabolic disorders like non-alcoholic steatohepatitis
(NASH). Forty New Zealand White rabbits have been used and fed a
high protein (HP) and energy diet based on grains and containing
11.76 MJ/kg. Boron added to 3 experimental groups’ drinking waters
(30 mg boron/L) as boron compounds. Biochemical analysis
including boron levels, and nuclear magnetic resonance (NMR) based
metabolomics evaluation, and mRNA expression of peroxisome
proliferator-activated receptor (PPAR) family was performed. LDLcholesterol
concentrations alone were decreased in all the
experimental groups. Boron levels in serum and feces were increased.
Content of acetate was in about 2x higher for anhydrous borax group,
at least 3x higher for boric acid group. PPARα mRNA expression
was significantly decreased in boric acid group. Anhydrous borax
attenuated mRNA levels of PPARγ, which was further suppressed by
boric acid. Boron supplementation decreased the degenerative
alterations in hepatocytes. Except borax group other boron groups did
not have a pronounced change in tubular epithels of kidney. In
conclusion, high protein and energy diet leads hepatocytes’
degenerative changes which can be prevented by boron
supplementation. Boric acid seems to be more effective in this
situation.
Abstract: The system for analyzing and eliciting public
grievances serves its main purpose to receive and process all sorts of
complaints from the public and respond to users. Due to the more
number of complaint data becomes big data which is difficult to store
and process. The proposed system uses HDFS to store the big data
and uses MapReduce to process the big data. The concept of cache
was applied in the system to provide immediate response and timely
action using big data analytics. Cache enabled big data increases the
response time of the system. The unstructured data provided by the
users are efficiently handled through map reduce algorithm. The
processing of complaints takes place in the order of the hierarchy of
the authority. The drawbacks of the traditional database system used
in the existing system are set forth by our system by using Cache
enabled Hadoop Distributed File System. MapReduce framework
codes have the possible to leak the sensitive data through
computation process. We propose a system that add noise to the
output of the reduce phase to avoid signaling the presence of
sensitive data. If the complaints are not processed in the ample time,
then automatically it is forwarded to the higher authority. Hence it
ensures assurance in processing. A copy of the filed complaint is sent
as a digitally signed PDF document to the user mail id which serves
as a proof. The system report serves to be an essential data while
making important decisions based on legislation.
Abstract: In the past decade, the use of digital image correlation
(DIC) techniques has increased significantly in the area of
experimental mechanics, especially for materials behavior
characterization. This non-contact tool enables full field displacement
and strain measurements over a complete region of interest. The DIC
algorithm requires a random contrast pattern on the surface of the
specimen in order to perform properly. To create this pattern, the
specimen is usually first coated using a white matt paint. Next, a
black random speckle pattern is applied using any suitable method. If
the applied paint coating is too thick, its top surface may not be able
to exactly follow the deformation of the specimen, and consequently,
the strain measurement might be underestimated. In the present
article, a study of the influence of the paint thickness on the strain
underestimation is performed for different strain levels. The results
are then compared to typical paint coating thicknesses applied by
experienced DIC users. A slight strain underestimation was observed
for paint coatings thicker than about 30μm. On the other hand, this
value was found to be uncommonly high compared to coating
thicknesses applied by DIC users.
Abstract: The popularity of quality management system models
continues to grow despite the transitional crisis in 2008. Their
development is associated with demands of the new requirements for
entrepreneurs, such as risk analysis projects and more emphasis on
supervision of outsourced processes. In parallel, it is appropriate to
focus attention on the selection of companies aspiring to a quality
management system. This is particularly important in the automotive
supplier industry, where requirements transferred to the levels in the
supply chain should be clear, transparent and fairly satisfied. The
author has carried out a series of researches aimed at finding the
factors that allow for the effective implementation of the quality
management system in automotive companies. The research was
focused on four groups of companies: 1) manufacturing (parts and
assemblies for the purpose of sale or for vehicle manufacturers), 2)
service (repair and maintenance of the car) 3) services for the
transport of goods or people, 4) commercial (auto parts and vehicles).
The identified determinants were divided into two types of criteria:
internal and external, as well as hard and soft. The article presents the
hard – technical factors that an automotive company must meet in
order to achieve the goal of the quality management system
implementation.
Abstract: Students' academic achievement, along with the
effects of different variables, has been a serious concern of educators
since long ago. This study was an attempt to investigate the interplay
of Locus of Control (LOC), academic achievement and biological
variables among Iranian online EFL Learners. The participants of the
study included 100 students of different age groups and genders
studying English online at Iran Language Institute (ILI), Isfahan,
Iran. The instrument used was Trice Academic LOC questionnaire
which identifies orientations of internality or externality. The
participants' Grade Point Averages (GPAs) were used as the measure
of their academic achievement. A series of independent samples ttests
were performed on the data. The results of the study showed that
(a) there were no significant differences between male and female
participants in LOC orientation, (b) there was no relationship
between LOC and academic achievement among internal males and
females, (c) external females were better achievers than external
males, (d) and the age had no significant relationship with LOC and
academic achievement. It can be concluded that the social, cultural
patterns of genders have changed. This study might help sociologists
and psychologists as well as applied linguists in that they reflect the
recent social changes and their effects on the LOC and their
consequent implications in teaching languages.