Abstract: Vancron 40, a nitrided powder metallurgical tool
Steel, is used in cold work applications where the predominant failure
mechanisms are adhesive wear or galling. Typical applications of
Vancron 40 are among others fine blanking, cold extrusion, deep
drawing and cold work rolls for cluster mills. Vancron 40 positive
results for cold work rolls for cluster mills and as a tool for some
severe metal forming process makes it competitive compared to other
type of work rolls that require higher precision, among others in cold
rolling of thin stainless steel, which required high surface finish
quality. In this project, three roll materials for cold rolling of stainless
steel strip was examined, Vancron 40, Narva 12B (a high-carbon,
high-chromium tool steel alloyed with tungsten) and Supra 3 (a
Chromium-molybdenum tungsten-vanadium alloyed high speed
steel). The purpose of this project was to study the depth profiles of
the ironed stainless steel strips, emergence of galling and to study the
lubrication performance used by steel industries. Laboratory
experiments were conducted to examine scratch of the strip, galling
and surface roughness of the roll materials under severe tribological
conditions. The critical sliding length for onset of galling was
estimated for stainless steel with four different lubricants. Laboratory
experiments result of performance evaluation of resistance capability
of rolls toward adhesive wear under severe conditions for low and
high reductions. Vancron 40 in combination with cold rolling
lubricant gave good surface quality, prevents galling of
metal surfaces and good bearing capacity.
Abstract: Risperidone (RISP) is an antipsychotic agent and has
low water solubility and nontargeted delivery results in numerous
side effects. Hence, an attempt was made to develop SLNs hydrogel
for intranasal delivery of RISP to achieve maximum bioavailability
and reduction of side effects. RISP loaded SLNs composed of 1.65%
(w/v) lipid mass were produced by high shear homogenization (HSH)
coupled ultrasound (US) method using glycerylmonostearate (GMS)
or Imwitor 900K (solid lipid). The particles were loaded with 0.2%
(w/v) of the RISP & surface-tailored with a 2.02% (w/v) non-ionic
surfactant Tween® 80. Optimization was done using 32 factorial
design using Design Expert® software. The prepared SLNs
dispersion incorporated into Polycarbophil AA1 hydrogel (0.5%
w/v). The final gel formulation was evaluated for entrapment
efficiency, particle size, rheological properties, X ray diffraction, in
vitro diffusion, ex vivo permeation using sheep nasal mucosa and
histopathological studies for nasocilliary toxicity. The entrapment
efficiency of optimized SLNs was found to be 76 ± 2%,
polydispersity index
Abstract: Compositions of different molar ratios of
polymethylmethacrylate-co-methacrylic acid (PMMA-co-MAA)
were synthesized via free-radical polymerization. Polymer coated
surfaces have been produced on silicon wafers. Coated samples were
analyzed by atomic force microscopy (AFM). The results have shown
that the roughness of the surfaces have increased by increasing the
molar ratio of monomer methacrylic acid (MAA). This study reveals
that the gradual increase in surface roughness is due to the fact that
carboxylic functional groups have been generated by MAA segments.
Such surfaces can be desirable platforms for fabrication of the
biosensors for detection of the viruses and diseases.
Abstract: Burnishing is increasingly used as a finishing operation to improve surface roughness and surface hardness. This can be achieved by applying a hard ball or roller onto metallic surfaces under pressure, in order to achieve many advantages in the metallic surface. In the present work, the feed rate, speed and force have been considered as the basic burnishing parameters to study the surface roughness and surface hardness of metallic matrix composites. The considered metal matrix composites were made from Aluminum-Magnesium-Graphite with five different weight percentage of graphite. Both effects of burnishing parameters mentioned above and the graphite percentage on the surface hardness and surface roughness of the metallic matrix composites were studied. The results of this investigation showed that the surface hardness of the metallic composites increases with the increase of the burnishing force and decreases with the increase in the burnishing feed rate and burnishing speed. The surface roughness of the metallic composites decreases with the increasing of the burnishing force, feed rate, and speed to certain values, then it starts to increase. On the other hand, the increase in the weight percentage of the graphite in the considered composites causes a decrease in the surface hardness and an increase in the surface roughness.
Abstract: The rate of natural gas dissociation from the Coal
Matrix depends on depressurization of reservoir through removing of
the cleat water from the coal seam. These waters are similar to brine
and aged of very long years. For improving the connectivity through
fracking /fracturing, high pressure liquids are pumped off inside the
coal body. A significant quantity of accumulated water, a combined
mixture of cleat water and fracking fluids (back flow water) is
pumped out through gas well. In Queensland, Australia Coal Seam
Gas (CSG) industry is in booming state and estimated of 30,000 wells
would be active for CSG production forecasting life span of 30 years.
Integrated water management along with water softening programs is
practiced for subsequent treatment and later on discharge to nearby
surface water catchment. Water treatment is an important part of the
CSG industry. A case study on a CSG site and review on the test
results are discussed for assessing the Standards & Practices for
management of CSG by-product water and their subsequent disposal
activities. This study was directed toward (i) water management and
softening process in Spring Gully CSG field, (ii) Comparative
analysis on experimental study and standards and (iii) Disposal of the
treated water. This study also aimed for alternative usages and their
impact on vegetation, living species as well as long term effects.
Abstract: Adsorption of a boron nitride nanotube (BNNT) was
examined toward ethylacetylene (C4H6) molecule by using density
functional theory (DFT) calculations at the B3LYP/6-31G (d) level,
and it was found that the adsorption energy (Ead) of ethylacetylene
the pristine nanotubes is about -1.60kcal/mol. But when nanotube has
been doped with Si and Al atoms, the adsorption energy of
ethylacetylene molecule was increased. Calculation showed that
when the nanotube is doping by Al, the adsorption energy is about -
24.19kcal/mol and also the amount of HOMO/LUMO energy gap
(Eg) will reduce significantly. Boron nitride nanotube is a suitable
adsorbent for ethylacetylene and can be used in separation processes
ethylacetylene. It is seem that nanotube (BNNT) is a suitable
semiconductor after doping, and the doped BNNT in the presence of
ethylacetylene an electrical signal is generating directly and therefore
can potentially be used for ethylacetylene sensors.
Abstract: In view of a possible application in optical data
storage devices, diffraction grating efficiency of an organic dye, Acid
Fuchsin doped in PMMA matrix was studied under excitation with
CW diode pumped Nd: YAG laser at 532 nm. The open aperture Zscan
of dye doped polymer displayed saturable absorption and the
closed aperture Z-scan of the samples exhibited negative
nonlinearity. The diffraction efficiency of the grating is the ratio of
the intensity of the first order diffracted power to the incident read
beam power. The dye doped polymer films were found to be good
media for recording. It is observed that the formation of gratings
strongly depend on the concentration of dye in the polymer film, the
intensity ratios of the writing beams and the angle between the
writing beams. It has been found that efficient writing can be made at
an angle of 20o and when the intensity ratio of the writing beams is
unity.
Abstract: Auckland has a temperate climate with comfortable warm, dry summers and mild, wet winters. An Auckland school normally does not need air conditioning for cooling during the summer and only needs heating during the winter. The Auckland school building thermal design should more focus on winter thermal performance and indoor thermal comfort for energy efficiency. This field study of testing indoor and outdoor air temperatures, relative humidity and indoor surface temperatures of three classrooms with different envelopes were carried out in the Avondale College during the winter months in 2013. According to the field study data, this study is to compare and evaluate winter thermal performance and indoor thermal conditions of school buildings with different envelopes.
Abstract: Karst term is the determiner of a variety of areas or
landforms and unique perspectives that have been formed in result of
the of the ingredients dissolution of rocks constituter by natural
waters. Shiraz area with an area of 5322km2 is located in the simple
folded belt in the southern part of Zagros Mountain of Fars, and is
surrounded with Limestone Mountains (Asmari formation). Shiraz
area is located in Calcareous areas. The infrastructure of this city is
lime and absorbing wells that the city can influence the Limestone
dissolution and those accelerate its rate and increase the cavitation
below the surface. Dasht-e Arjan is a graben, which has been created
as the result of activity of two normal faults in its east and west sides.
It is a complete sample of Karst plains (Polje) which has been created
with the help of tectonic forces (fault) and dissolution process of
water in Asmari limestone formation. It is located 60km. off south
west of Shiraz (on Kazeroon-Shiraz road). In 1971, UNESCO has
recognized this plain as a reserve of biosphere. It is considered as one
of the world’s most beautiful geological phenomena, so that most of
the world’s geologists are interested in visiting this place. The
purpose of this paper is to identify and introduce landscapes of Karst
features shiraz city and Dasht-e Arjan including Karst dissolution
features (Lapiez, Karst springs, dolines, caves, underground caves,
ponors, and Karst valleys), anticlines and synclines, and Arjan Lake.
Abstract: Testing the first year students of Informatics at the
University of Debrecen revealed that students start their tertiary
studies in programming with a low level of programming knowledge
and algorithmic skills. The possible reasons which lead the students
to this very unfortunate result were examined. The results of the test
were compared to the students’ results in the school leaving exams
and to their self-assessment values. It was found that there is only a
slight connection between the students’ results in the test and in the
school leaving exams, especially at intermediate level. Beyond this,
the school leaving exams do not seem to enable students to evaluate
their own abilities.
Abstract: In the scope of application of technical textiles, Non-
Crimp Fabrics are increasingly used. In general, NCF exhibit
excellent load bearing properties, but caused by the manufacturing
process, there are some remaining disadvantages which have to be
reduced. Regarding to this, a novel technique of processing NCF was
developed substituting the binding-thread by an adhesive. This stitchfree
method requires new manufacturing concept as well as new basic
methods to prove adhesion of glue at fibres and textiles. To improve
adhesion properties and the wettability of carbon-fibres by the
adhesive, oxy-fluorination was used. The modification of carbonfibres
by oxy-fluorination was investigated via scanning electron
microscope, X-ray photoelectron spectroscopy and single fibre
tensiometry. Special tensile tests were developed to determine the
maximum force required for detachment.
Abstract: Water spray cooling is a technique typically used in
heat treatment and other metallurgical processes where controlled
temperature regimes are required. Water spray cooling is used in
static (without movement) or dynamic (with movement of the steel
plate) regimes. The static regime is notable for the fixed position of
the hot steel plate and fixed spray nozzle. This regime is typical for
quenching systems focused on heat treatment of the steel plate. The
second application of spray cooling is the dynamic regime. The
dynamic regime is notable for its static section cooling system and
moving steel plate. This regime is used in rolling and finishing mills.
The fixed position of cooling sections with nozzles and the
movement of the steel plate produce nonhomogeneous water
distribution on the steel plate. The length of cooling sections and
placement of water nozzles in combination with the nonhomogeneity
of water distribution lead to discontinued or interrupted cooling
conditions. The impact of static and dynamic regimes on cooling
intensity and the heat transfer coefficient during the cooling process
of steel plates is an important issue.
Heat treatment of steel is accompanied by oxide scale growth. The
oxide scale layers can significantly modify the cooling properties and
intensity during the cooling. The combination of static and dynamic
(section) regimes with the variable thickness of the oxide scale layer
on the steel surface impact the final cooling intensity. The study of
the influence of the oxide scale layers with different cooling regimes
was carried out using experimental measurements and numerical
analysis. The experimental measurements compared both types of
cooling regimes and the cooling of scale-free surfaces and oxidized
surfaces. A numerical analysis was prepared to simulate the cooling
process with different conditions of the section and samples with
different oxide scale layers.
Abstract: In this study the instability problem of a modified
Taylor-Couette flow between two vertical coaxial cylinders of radius
R1, R2 is considered. The modification is based on the wavy shape of
the inner cylinder surface, where inner cylinders with different
surface amplitude and wavelength are used. The study aims to
discover the effect of the inner surface geometry on the instability
phenomenon that undergoes Taylor-Couette flow. The study reveals
that the transition processes depends strongly on the amplitude and
wavelength of the inner cylinder surface and resulting in flow
instabilities that are strongly different from that encountered in the
case of the classical Taylor-Couette flow.
Abstract: In order to manufacture short gap single Si nanowire
(NW) field effect transistor (FET) by imprinting and transferring
method, we introduce the method using Al2O3 sacrificial layer. The
diameters of cylindrical Si NW addressed between Au electrodes by
dielectrophoretic (DEP) alignment method are controlled to 106, 128,
and 148 nm. After imprinting and transfer process, cylindrical Si NW
is embedded in PVP adhesive and dielectric layer. By curing
transferred cylindrical Si NW and Au electrodes on PVP-coated p++ Si
substrate with 200nm-thick SiO2, 3μm gap Si NW FET fabrication
was completed. As the diameter of embedded Si NW increases, the
mobility of FET increases from 80.51 to 121.24 cm2/V·s and the
threshold voltage moves from –7.17 to –2.44 V because the ratio of
surface to volume gets reduced.
Abstract: The exact theoretical expression describing the
probability distribution of nonlinear sea-surface elevations derived
from the second-order narrowband model has a cumbersome form
that requires numerical computations, not well-disposed to theoretical
or practical applications. Here, the same narrowband model is reexamined
to develop a simpler closed-form approximation suitable
for theoretical and practical applications. The salient features of the
approximate form are explored, and its relative validity is verified
with comparisons to other readily available approximations, and
oceanic data.
Abstract: Taking the design tolerance into account, this paper
presents a novel efficient approach to generate iso-scallop tool path for
five-axis strip machining with a barrel cutter. The cutter location is
first determined on the scallop surface instead of the design surface,
and then the cutter is adjusted to locate the optimal tool position based
on the differential rotation of the tool axis and satisfies the design
tolerance simultaneously. The machining strip width and error are
calculated with the aid of the grazing curve of the cutter. Based on the
proposed tool positioning algorithm, the tool paths are generated by
keeping the scallop height formed by adjacent tool paths constant. An
example is conducted to confirm the validity of the proposed method.
Abstract: In this research, waterglass based aerogel powder was
prepared by sol–gel process and ambient pressure drying. Inspired by
limited dust releasing, aerogel powder was introduced to the PET
electrospinning solution in an attempt to create required bulk and
surface structure for the nanofibers to improve their hydrophobic and
insulation properties. The samples evaluation was carried out by
measuring density, porosity, contact angle, heat transfer, FTIR, BET,
and SEM. According to the results, porous silica aerogel powder was
fabricated with mean pore diameter of 24 nm and contact angle of
145.9º. The results indicated the usefulness of the aerogel powder
confined into nanofibers to control surface roughness for
manipulating superhydrophobic nanowebs with water contact angle
of 147º. It can be due to a multi-scale surface roughness which was
created by nanowebs structure itself and nanofibers surface
irregularity in presence of the aerogels while a layer of fluorocarbon
created low surface energy. The wettability of a solid substrate is an
important property that is controlled by both the chemical
composition and geometry of the surface. Also, a decreasing trend in
the heat transfer was observed from 22% for the nanofibers without
any aerogel powder to 8% for the nanofibers with 4% aerogel
powder. The development of thermal insulating materials has become
increasingly more important than ever in view of the fossil energy
depletion and global warming that call for more demanding energysaving
practices.
Abstract: To develop AZ91D magnesium alloys with improved
properties, we have applied TiN and VN/TiN multilayer coatings
using DC magnetron sputter technique. Coating structure, surface
morphology, chemical bonding and corrosion resistance of coatings
were analyzed by x-ray diffraction (XRD), scanning electron
microscope (SEM), x-ray photoelectron spectroscopy (XPS), and
tafel extrapolation method, respectively. XPS analysis reveal that VN
overlayer reacts with oxygen at the VN/TiN interface and forms more
stable TiN layer. Morphological investigations and the corrosion
results show that VN/TiN multilayer thin film coatings are quite
effective to optimize the corrosion resistance of Mg alloys.
Abstract: Axial flow fans, while incapable of developing high
pressures, they are well suitable for handling large volumes of air at
relatively low pressures. In general, they are low in cost and possess
good efficiency, and can have blades of airfoil shape. Axial flow fans
show good efficiencies, and can operate at high static pressures if
such operation is necessary. Our objective is to model and analyze
the flow through AXIAL FANS using CFD Software and draw
inference from the obtained results, so as to get maximum efficiency.
The performance of an axial fan was simulated using CFD and the
effect of variation of different parameters such as the blade number,
noise level, velocity, temperature and pressure distribution on the
blade surface was studied. This paper aims to present a final 3D CAD
model of axial flow fan. Adapting this model to the available
components in the market, the first optimization was done. After this
step, CFX flow solver is used to do the necessary numerical analyses
on the aerodynamic performance of this model. This analysis results
in a final optimization of the proposed 3D model which is presented
in this article.
Abstract: Machining parameters are very important in
determining the surface quality of any material. In the past decade,
some new engineering materials were developed for the
manufacturing industry which created a need to conduct an
investigation on the impact of the said parameters on their surface
roughness. Polyurethane (PU) block is widely used in the automotive
industry to manufacture parts such as checking fixtures that are used
to verify the dimensional accuracy of automotive parts. In this paper,
the design of experiment (DOE) was used to investigate on the effect
of the milling parameters on the PU block. Furthermore, an analysis
of the machined surface chemical composition was done using
scanning electron microscope (SEM). It was found that the surface
roughness of the PU block is severely affected when PU undergoes a
flood machining process instead of a dry condition. In addition the
stepover and the silicon content were found to be the most significant
parameters that influence the surface quality of the PU block.