Abstract: We report herein the development and preliminary mechanical characterization of fully-dense multi-wall carbon nanotube (MWCNT)-reinforced ceramics and glasses based on a completely new methodology termed High Shear Compaction (HSC). The tubes are introduced and bound to the matrix grains by aid of polymeric binders to form flexible green bodies which are sintered and densified by spark plasma sintering to unprecedentedly high densities of 100% of the pure-matrix value. The strategy was validated across a PyrexTM glass / MWCNT composite while no identifiable factors limit application to other types of matrices. Nondestructive evaluation, based on ultrasonics, of the dynamic mechanical properties of the materials including elastic, shear and bulk modulus as well as Poisson’s ratio showed optimum property improvement at 0.5 %wt tube loading while evidence of nanoscalespecific energy dissipative characteristics acting complementary to nanotube bridging and pull-out indicate a high potential in a wide range of reinforcing and multifunctional applications.
Abstract: In the present study, response surface methodology has been used to optimize turn-assisted deep cold rolling process of AISI 4140 steel. A regression model is developed to predict surface hardness and surface roughness using response surface methodology and central composite design. In the development of predictive model, deep cold rolling force, ball diameter, initial roughness of the workpiece, and number of tool passes are considered as model variables. The rolling force and the ball diameter are the significant factors on the surface hardness and ball diameter and numbers of tool passes are found to be significant for surface roughness. The predicted surface hardness and surface roughness values and the subsequent verification experiments under the optimal operating conditions confirmed the validity of the predicted model. The absolute average error between the experimental and predicted values at the optimal combination of parameter settings for surface hardness and surface roughness is calculated as 0.16% and 1.58% respectively. Using the optimal processing parameters, the surface hardness is improved from 225 to 306 HV, which resulted in an increase in the near surface hardness by about 36% and the surface roughness is improved from 4.84µm to 0.252 µm, which resulted in decrease in the surface roughness by about 95%. The depth of compression is found to be more than 300µm from the microstructure analysis and this is in correlation with the results obtained from the microhardness measurements. Taylor hobson talysurf tester, micro vickers hardness tester, optical microscopy and X-ray diffractometer are used to characterize the modified surface layer.
Abstract: Intermittent behavior near the boundary of phase
synchronization in the presence of noise is studied. In certain range of
the coupling parameter and noise intensity the intermittency of eyelet
and ring intermittencies is shown to take place. Main results are
illustrated using the example of two unidirectional coupled Rössler
systems. Similar behavior is shown to take place in two
hydrodynamical models of Pierce diode coupled unidirectional.
Abstract: The aim of this investigation is to elaborate nearinfrared
methods for testing and recognition of chemical components
and quality in “Pannon wheat” allied (i.e. true to variety or variety
identified) milling fractions as well as to develop spectroscopic
methods following the milling processes and evaluate the stability of
the milling technology by different types of milling products and
according to sampling times, respectively. These wheat categories
produced under industrial conditions where samples were collected
versus sampling time and maximum or minimum yields. The changes
of the main chemical components (such as starch, protein, lipid) and
physical properties of fractions (particle size) were analysed by
dispersive spectrophotometers using visible (VIS) and near-infrared
(NIR) regions of the electromagnetic radiation. Close correlation
were obtained between the data of spectroscopic measurement
techniques processed by various chemometric methods (e.g. principal
component analysis [PCA], cluster analysis [CA]) and operation
condition of milling technology. It is obvious that NIR methods are
able to detect the deviation of the yield parameters and differences of
the sampling times by a wide variety of fractions, respectively. NIR
technology can be used in the sensitive monitoring of milling
technology.
Abstract: Stress of slaughter animals starting long before until at the time of process of slaughtering which cause misery and decrease of meat quality. Meanwhile, determination of animal stress using hormonal such as cortisol is expensive and less practical so that portable stress indicator for cows based on Fourier Transform Infrared Spectroscopy (FTIR) must be provided. The aims of this research are to find out the comparison process of slaughter between Rope Casting Local (RCL) and Restraining Box Method (RBM) by measuring of cortisol and wavelength in FTIR methods. Thirty two of male Ongole crossbred cattle were used in this experiment. Blood sampling was taken from jugular vein when they were rested and repeated when slaughtered. All of blood samples were centrifuged at 3000 rpm for 20 minutes to get serum, and then divided into two parts for cortisol assayed using ELISA and for measuring the wavelength using FTIR. The serum then measured at the wavelength between 4000-400 cm-1 using MB3000 FTIR. Band data absorption in wavelength of FTIR is analyzed descriptively by using FTIR Horizon MBTM. For RCL, average of serum cortisol when the animals rested were 11.47 ± 4.88 ng/mL, when the time of slaughter were 23.27 ± 7.84 ng/mL. For RBM, level of cortisol when rested animals were 13.67 ± 3.41 ng/mL and 53.47 ± 20.25 ng/mL during the slaughter. Based on student t-Test, there were significantly different between RBM and RCL methods when beef cattle were slaughtered (P0.05). Result of FTIR with the various of wavelength such as methyl group (=CH3 ) 2986cm-1, methylene (=CH2 ) 2827 cm-1, hydroxyl (- OH) 3371 cm-1, carbonyl (ketones) (C=O) 1636 cm-1, carboxyl (COO-1) 1408 cm-1, glucosa 1057 cm-1, urea 1011 cm-1have been obtained. It can be concluded that the RCL slaughtered method is better than the RBM method based on the increase of cortisol as an indicator of stress in beef cattle (P
Abstract: This paper addresses a cutting edge method of
business demand forecasting, based on an empirical probability
function when the historical behavior of the data is random.
Additionally, it presents error determination based on the numerical
method technique ‘propagation of errors.’ The methodology was
conducted characterization and process diagnostics demand planning
as part of the production management, then new ways to predict its
value through techniques of probability and to calculate their mistake
investigated, it was tools used numerical methods. All this based on
the behavior of the data. This analysis was determined considering
the specific business circumstances of a company in the sector of
communications, located in the city of Bogota, Colombia. In
conclusion, using this application it was possible to obtain the
adequate stock of the products required by the company to provide its
services, helping the company reduce its service time, increase the
client satisfaction rate, reduce stock which has not been in rotation
for a long time, code its inventory, and plan reorder points for the
replenishment of stock.
Abstract: Methicillin/multiple-resistant Staphylococcus aureus
(MRSA) are infectious bacteria that are resistant to common
antibiotics. A previous in silico study in our group has identified a
hypothetical protein SAV1226 as one of the potential drug targets. In
this study, we reported the bioinformatics characterization, as well as
cloning, expression, purification and kinetic assays of hypothetical
protein SAV1226 from methicillin/vancomycin-resistant
Staphylococcus aureus Mu50 strain. MALDI-TOF/MS analysis
revealed a low degree of structural similarity with known proteins.
Kinetic assays demonstrated that hypothetical protein SAV1226 is
neither a domain of an ATP dependent dihydroxyacetone kinase nor
of a phosphotransferase system (PTS) dihydroxyacetone kinase,
suggesting that the function of hypothetical protein SAV1226 might
be misannotated on public databases such as UniProt and
InterProScan 5.
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: The nanoindentation behaviour and phase
transformation of annealed single-crystal silicon wafers are examined.
The silicon specimens are annealed at temperatures of 250, 350 and
450ºC, respectively, for 15 minutes and are then indented to maximum
loads of 30, 50 and 70 mN. The phase changes induced in the indented
specimens are observed using transmission electron microscopy
(TEM) and micro-Raman scattering spectroscopy (RSS). For all
annealing temperatures, an elbow feature is observed in the unloading
curve following indentation to a maximum load of 30 mN. Under
higher loads of 50 mN and 70 mN, respectively, the elbow feature is
replaced by a pop-out event. The elbow feature reveals a complete
amorphous phase transformation within the indented zone, whereas
the pop-out event indicates the formation of Si XII and Si III phases.
The experimental results show that the formation of these crystalline
silicon phases increases with an increasing annealing temperature and
indentation load. The hardness and Young’s modulus both decrease as
the annealing temperature and indentation load are increased.
Abstract: This paper pioneers Care Robot Impact Assessment
(CRIA), a methodology used to identify, analyze, mitigate and
eliminate the risks posed by the insertion of non-medical personal
care robots (PCR) in medical care facilities. Its precedent instruments
[Privacy and Surveillance Impact Assessment (PIA and SIA)] fall
behind in coping with robots. Indeed, personal care robots change
dramatically how care is delivered. The paper presents a specific
risk-sector methodology, identifies which robots are under its scope
and presents some of the challenges introduced by these robots.
Abstract: In the present research work we present the optical
emission studies of the Indium (In) – Tin (Sn) plasma produced by
the first (1064 nm) harmonic of an Nd: YAG nanosecond pulsed
laser. The experimentally observed line profiles of neutral Indium (In
I) and Tin (SnI) are used to extract the electron temperature (Te)
using the Boltzmann plot method. Whereas, the electron number
density (Ne) has been determined from the Stark broadening line
profile method. The Te is calculated by varying the distance from the
target surface along the line of propagation of plasma plume and also
by varying the laser irradiance. Beside we have studied the variation
of Ne as a function of laser irradiance as well as its variation with
distance from the target surface.
Abstract: Development of new generation bio-tribological,
multilayer coatings opens an avenue for fabrication of future hightech
functional surfaces. In the presented work, nano-composite,
Cr/CrN+[Cr/ a-C:H implanted by metallic nanocrystals] multilayer
coatings have been developed for surface protection of medical tools.
Thin films were fabricated by a hybrid Pulsed Laser Deposition
technique. Complex microstructure analysis of nanomultilayer
coatings, subjected to mechanical and biological tests, were
performed by means of transmission electron microscopy (TEM).
Microstructure characterization revealed the layered arrangement of
Cr23C6 nanoparticles in multilayer structure. Influence of deposition
conditions on bio-tribological properties of the coatings was studied.
The bio-tests were used as a screening tool for the analyzed
nanomultilayer coatings before they could be deposited on medical
tools. Bio-medical tests were done using fibroblasts. The mechanical
properties of the coatings were investigated by means of a ball-ondisc
mechanical test. The micro hardness was done using Berkovich
indenter. The scratch adhesion test was done using Rockwell
indenter. From the bio-tribological point of view, the optimal
properties had the C106_1 material.
Abstract: New design of three dimensional (3D) flywheel system
based on gimbal and gyro mechanics is proposed. The 3D flywheel
device utilizes the rotational motion of three spherical shells and the
conservation of angular momentum to achieve planar locomotion.
Actuators mounted to the ring-shape frames are installed within the
system to drive the spherical shells to rotate, for the purpose of steering
and stabilization. Similar to the design of 2D flywheel system, it is
expected that the spherical shells may function like a “flyball” to store
and supply mechanical energy; additionally, in comparison with
typical single-wheel and spherical robots, the 3D flywheel can be used
for developing omnidirectional robotic systems with better mobility.
The Lagrangian method is applied to derive the equation of motion of
the 3D flywheel system, and simulation studies are presented to verify
the proposed design.
Abstract: Potassium borates, which are widely used in welding
and metal refining industry, as a lubricating oil additive, cement
additive, fiberglass additive and insulation compound, are one of the
important groups of borate minerals. In this study the production of a
potassium borate mineral via hydrothermal method is aimed. The
potassium source of potassium nitrate (KNO3) was used along with a
sodium source of sodium hydroxide (NaOH) and boron source of
boric acid (H3BO3). The constant parameters of reaction temperature
and reaction time were determined as 80°C and 1 h, respectively. The
molar ratios of 1:1:3 (as KNO3:NaOH:H3BO3), 1:1:4, 1:1:5, 1:1:6
and 1:1:7 were used. Following the synthesis the identifications of
the produced products were conducted by X-Ray Diffraction (XRD),
Fourier Transform Infrared Spectroscopy (FT-IR) and Raman
Spectroscopy. The results of the experiments and analysis showed in
the ratio of 1:1:6, the Santite mineral with powder diffraction file
number (pdf no.) of 01-072-1688, which is known as potassium
pentaborate (KB5O8·4H2O) was synthesized as best.
Abstract: Intermetallic materials are among advanced
technology materials that have outstanding mechanical and physical
properties for high temperature applications. Especially creep
resistance, low density and high hardness properties stand out in such
intermetallics. The microstructure, mechanical properties of %88Ni-
%10Cr and %2Mn powders were investigated using specimens
produced by tube furnace sintering at 900-1300°C temperature. A
composite consisting of ternary additions, a metallic phase, Fe, Cr
and Mn have been prepared under Ar shroud and then tube furnace
sintered. XRD, SEM (Scanning Electron Microscope), were
investigated to characterize the properties of the specimens.
Experimental results carried out for composition %88Ni-%10Cr and
%2Mn at 1300°C suggest that the best properties as 138,80HV and
6,269/cm3 density were obtained at 1300°C.
Abstract: The aim of this study is to investigate formability of
Al based closed cell metallic foams at high temperature. The foam
specimens with rectangular section were produced from
AlMg1Si0.6TiH20.8 alloy preform material. Bending and free
bending tests based on gravity effect were applied to foam specimens
at high temperatures. During the tests, the time-angular deformation
relationships with various temperatures were determined.
Deformation types formed in cell walls were investigated by means
of Scanning Electron Microscopy (SEM) and optical microscopy.
Bending deformation about 90° was achieved without any defect at
high temperatures. The importance of a critical temperature and
deformation rate was emphasized in maintaining the deformation.
Significant slip lines on surface of cell walls at tensile zones of
bending specimen were observed. At high strain rates, the microcrack
formation in boundaries of elongated grains was determined.
Abstract: Chitosan functionalized Fe3O4-Au core shell
nanoparticles have been prepared using a two-step wet chemical
approach using NaBH4 as reducing agent for formation of Au in
ethylene glycol. X-ray diffraction studies shows individual phases of
Fe3O4 and Au in the as prepared samples with crystallite size of 5.9
and 11.4 nm respectively. The functionalization of the core-shell
nanostructure with Chitosan has been confirmed using Fourier
transform infrared spectroscopy along with signatures of octahedral
and tetrahedral sites of Fe3O4 below 600cm-1. Mössbauer
spectroscopy shows decrease in particle-particle interaction in
presence of Au shell (72% sextet) than pure oleic coated Fe3O4
nanoparticles (88% sextet) at room temperature. At 80K, oleic acid
coated Fe3O4 shows only sextets whereas the Chitosan functionalized
Fe3O4 and Chitosan functionalized Fe3O4@Au core shell show
presence of 5 and 11% doublet, respectively.
Abstract: Fabric textures are very common in our daily life.
However, the representation of fabric textures has never been explored
from neuroscience view. Theoretical studies suggest that primary
visual cortex (V1) uses a sparse code to efficiently represent natural
images. However, how the simple cells in V1 encode the artificial
textures is still a mystery. So, here we will take fabric texture as
stimulus to study the response of independent component analysis that
is established to model the receptive field of simple cells in V1. We
choose 140 types of fabrics to get the classical fabric textures as
materials. Experiment results indicate that the receptive fields of
simple cells have obvious selectivity in orientation, frequency and
phase when drifting gratings are used to determine their tuning
properties. Additionally, the distribution of optimal orientation and
frequency shows that the patch size selected from each original fabric
image has a significant effect on the frequency selectivity.
Abstract: The separation of Hg (II) from produced water by
hollow fiber contactors (HFC) was investigation. This system
included of two hollow fiber modules in the series connecting. The
first module used for the extraction reaction and the second module
for stripping reaction. Aliquat336 extractant was fed from the organic
reservoirs into the shell side of the first hollow fiber module and
continuous to the shell side of the second module. The organic liquid
was continuously feed recirculate and back to the reservoirs. The feed
solution was pumped into the lumen (tube side) of the first hollow
fiber module. Simultaneously, the stripping solution was pumped in
the same way in tube side of the second module. The feed and
stripping solution was fed which had a countercurrent flow. Samples
were kept in the outlet of feed and stripping solution at 1 hour and
characterized concentration of Hg (II) by Inductively Couple Plasma
Atomic Emission Spectroscopy (ICP-AES). Feed solution was
produced water from natural gulf of Thailand. The extractant was
Aliquat336 dissolved in kerosene diluent. Stripping solution used was
nitric acid (HNO3) and thiourea (NH2CSNH2). The effect of carrier
concentration and type of stripping solution were investigated.
Results showed that the best condition were 10 % (v/v) Aliquat336
and 1.0 M NH2CSNH2. At the optimum condition, the extraction and
stripping of Hg (II) were 98% and 44.2%, respectively.
Abstract: Dielectric ceramic samples in the BaO-Re2O3-TiO2
ternary system were synthesized with structural formula Ba2-
xRe4+2x/3Ti8O24 where Re= rare earth metal and Re= Sm and La where
x varies from 0.0 to 0.6 with step size 0.1. Polycrystalline samples
were prepared by the conventional solid state reaction technique. The
dielectric, electrical and impedance analysis of all the samples in the
frequency range 1KHz- 1MHz at room temperature (25°C) have been
done to get the understanding of electrical conduction and dielectric
relaxation and their correlation. Dielectric response of the samples at
lower frequencies shows dielectric dispersion while at higher
frequencies it shows dielectric relaxation. The ac conductivity is well
fitted by the Jonscher law. The spectroscopic data in the impedance
plane confirms the existence of grain contribution to the relaxation.
All the properties are found out to be function of frequency as well as
the amount of substitution.