Abstract: Thin-walled elements with a matrix set on a base of
high-valuable Portland cement with dispersed reinforcement from
alkali-resistant glass fibres are used in a range of applications as
claddings of buildings and infrastructure constructions as well as
various architectural elements of residential buildings.
Even though their elementary thickness and therefore total weight
is quite low, architects and building companies demand on even
further decreasing of the bulk density of these fibre-cement elements
for the reason of loading elimination of connected superstructures
and easier assembling in demand conditions.
By the means of various kinds of light-weight aggregates it is
possible to achieve light-weighing of these composite elements.
From the range of possible fillers with different material properties
granulated expanded glass worked the best.
By the means of laboratory testing an effect of two fillers based on
expanded glass on the fibre reinforced cement composite was
verified.
Practical applicability was tested in the production of commonly
manufactured glass fibre reinforced concrete elements, such as
channels for electrical cable deposition, products for urban equipment
and especially various cladding elements.
Even though these are not structural elements, it is necessary to
evaluate also strength characteristics and resistance to environment
for their durability in certain applications.
Abstract: Skin aging is a slow multifactorial process influenced
by both internal as well as external factors. Ultra-violet radiations
(UV), diet, smoking and personal habits are the most common
environmental factors that affect skin aging. Fat contents and fibrous
proteins as collagen and elastin are core internal structural
components. The direct influence of UV on elastin integrity and
health is central on aging of skin especially by time. The deposition
of abnormal elastic material is a major marker in a photo-aged skin.
Searching for compounds that may protect against cutaneous photodamage
is exceedingly valued. Retinoids and alpha hydroxy acids
have been endorsed by some researchers as possible candidates for
protecting and or repairing the effect of UV damaged skin. For
consolidating a better system of anti- and protective effects of such
anti-aging agents, we evaluated the combinatory effects of various
dosages of lactic acid and retinol on the dermal fibroblast’s elastin
levels exposed to UV. The UV exposed cells showed significant
reduction in the elastin levels. A combination of drugs with a higher
concentration of lactic acid (30 -35 mM) and a lower concentration of
retinol (10-15mg/mL) showed to work better in maintaining elastin
concentration in UV exposed cells. We assume this preservation
could be the result of increased tropo-elastin gene expression
stimulated by retinol whereas lactic acid probably repaired the UV
irradiated damage by enhancing the amount and integrity of the
elastin fibers.
Abstract: Carbon Deposits are often occurred inside the
industrial coke oven during coking process. Accumulation of carbon
deposits may cause a big issue, which seriously influences the coking
operation. The carbon is burning off by injecting fresh air through
pipes into coke oven which is an efficient way practically operated in
industries. The burning off carbon deposition in coke oven performed
by Computational Fluid Dynamics (CFD) method has provided an
evaluation of the feasibility study. A three dimensional, transient,
turbulent reacting flow simulation has performed with three different
injecting air flow rate and another kind of injecting configuration. The
result shows that injection higher air flow rate would effectively
reduce the carbon deposits. In the meantime, the opened charging
holes would suck extra oxygen from atmosphere to participate in
reactions. In term of coke oven operating limits, the wall temperatures
are monitored to prevent over-heating of the adiabatic walls during
burn-off process.
Abstract: A nanocrystalline thin film of ZnSe was successfully
electrodeposited on copper substrate using a non-aqueous solution
and subsequently annealed in air at 400°C. XRD analysis indicates
the polycrystalline deposit of (111) plane in both the cases. The
sharpness of the peak increases due to annealing of the film and
average grain size increases to 20 nm to 27nm. SEM photograph
indicate that grains are uniform and densely distributed over the
surface. Annealing increases the average grain size by 20%. The EDS
spectroscopy shows the ratio of Zn & Se is 1.1 in case of annealed
film. AFM analysis indicates the average roughness of the film
reduces from 181nm to 165nm due to annealing of the film. The
bandgap also decreases from 2.71eV to 2.62eV.
Abstract: In this paper, two options of anodic alumina barrier
layer thinning have been demonstrated. The approaches varied with
the duration of the voltage step. It was found that too long step of the
barrier layer thinning process leads to chemical etching of the
nanopores on their top. At the bottoms pores are not fully opened
what is disadvantageous for further applications in nanofabrication.
On the other hand, while the duration of the voltage step is controlled
by the current density (value of the current density cannot exceed
75% of the value recorded during previous voltage step) the pores are
fully opened. However, pores at the bottom obtained with this
procedure have smaller diameter, nevertheless this procedure
provides electric contact between the bare aluminum (substrate) and
electrolyte, what is suitable for template assisted electrodeposition,
one of the most cost-efficient synthesis method in nanotechnology.
Abstract: In this paper, effect of marginal quality groundwater
on yield of cotton crop and soil salinity was studied. In this
connection, three irrigation treatments each with four replications
were applied. These treatments were i) use of canal water (T1), ii) use
of marginal quality groundwater from tubewell (T2), and iii)
conjunctive use by mixing with the ratio of 1:1 of canal water and
marginal quality tubewell water (T3).
Water was applied to the crop cultivated in Kharif season 2011; its
quantity has been measured using cut-throat flume. Total 11 watering
each of 50 mm depth have been applied from 20th April to 20th July,
2011. Further, irrigations were stopped due to monsoon rainfall up to
crop harvesting.
Maximum crop yield (seed cotton) was observed under T1 which
was 1,517 kg/ha followed by T3 (mixed canal and tubewell water)
having 1009 kg/ha and T2 i.e. marginal quality groundwater having
709 kg/ha. This concludes that crop yield in T2 and T3 in comparison
to T1was reduced by about 53 and 30% respectively.
It has been observed that yield of cotton crop is below potential
limit for three treatments due to unexpected rainfall at the time of full
flowering season; thus the yield was adversely affected.
However, salt deposition in soil profiles was not observed that is
due to leaching effect of heavy rainfall occurred during monsoon
season.
Abstract: Carbon nanotube is one of the most attractive materials
for the potential applications of nanotechnology due to its excellent
mechanical, thermal, electrical and optical properties. In this paper we
report a supercapacitor made of nickel foil electrodes, coated with
multiwall carbon nanotubes (MWCNTs) thin film using
electrophoretic deposition (EPD) method. Chemical vapor deposition
method was used for the growth of MWCNTs and ethanol was used as
a hydrocarbon source. High graphitic multiwall carbon nanotube was
found at 750oC analyzing by Raman spectroscopy. We observed the
electrochemical performance of supercapacitor by cyclic
voltammetry. The electrodes of supercapacitor fabricated from
MWCNTs exhibit considerably small equivalent series resistance
(ESR), and a high specific power density. Electrophoretic deposition
is an easy method in fabricating MWCNT electrodes for high
performance supercapacitor.
Abstract: This study presents a cost-effective approach for rapid
fabricating modeling platforms utilized in fused deposition modeling
system. A small-batch production of modeling platforms about 20
pieces can be obtained economically through silicone rubber mold
using vacuum casting without applying the plastic injection molding.
The air venting systems is crucial for fabricating modeling platform
using vacuum casting. Modeling platforms fabricated can be used for
building rapid prototyping model after sandblasting. This study offers
industrial value because it has both time-effectiveness and
cost-effectiveness.
Abstract: The hydrogenated amorphous carbon films (α-C:H)
were deposited on p-type Si (100) substrates at different thicknesses by
radio frequency plasma enhanced chemical vapor deposition
technique (rf-PECVD). Raman spectra display asymmetric
diamond-like carbon (DLC) peaks, representative of the α-C:H films.
The decrease of intensity ID/IG ratios revealed the sp3 content arise at
different thicknesses of the α-C:H films. In terms of mechanical
properties, the high hardness and elastic modulus values showed the
elastic and plastic deformation behaviors related to sp3 content in
amorphous carbon films. Electrochemical properties showed that the
α-C:H films exhibited excellent corrosion resistance in air-saturated
3.5 wt.% NaCl solution for pH 2 at room temperature. Thickness
increasing affected the small sp2 clusters in matrix, restricting the
velocity transfer and exchange of electrons. The deposited α-C:H films
exhibited excellent mechanical properties and corrosion resistance.
Abstract: Hydrogenated amorphous carbon (a-C:H) films have
been synthesized by a radio frequency plasma enhanced chemical
vapor deposition (rf-PECVD) technique with different bias voltage
from 0.0 to -0.5 kV. The Raman spectra displayed the polymer-like
hydrogenated amorphous carbon (PLCH) film with 0.0 to -0.1 and
a-C:H films with -0.2 to -0.5 kV of bias voltages. The surface chemical
information of all films were studied by X-ray photoelectron
spectroscopy (XPS) technique, presented to C-C (sp2 and sp3) and C-O
bonds, and relative carbon (C) and oxygen (O) atomics contents. The
O contamination had affected on structure and optical properties. The
true density of PLCH and a-C:H films were characterized by X-ray
refractivity (XRR) method, showed the result as in the range of
1.16-1.73 g/cm3 that depending on an increasing of bias voltage. The
hardness was proportional to the true density of films. In addition, the
optical properties i.e. refractive index (n) and extinction coefficient (k)
of these films were determined by a spectroscopic ellipsometry (SE)
method that give formation to in 1.62-2.10 (n) and 0.04-0.15 (k)
respectively. These results indicated that the optical properties
confirmed the Raman results as presenting the structure changed with
applied bias voltage increased.
Abstract: Multiwall carbon nanotubes, prepared by chemical
vapor deposition, have an average diameter of 60-100 nm as shown
by High Resolution Transmittance Electron Microscope, HR-TEM.
The Multiwall carbon nanotubes (MWCNTs) were further
characterized using X-ray Diffraction and Raman Spectroscopy.
Mercury uptake capacity of MWCNTs was studied using batch
adsorption method at different concentration ranges up to 150 ppm.
Mercury concentration (before and after the treatment) was measured
using cold vapor atomic absorption spectroscopy. The effect of time,
concentration, pH and adsorbent dose were studied. MWCNT were
found to perform complete absorption in the sub-ppm concentrations
(parts per billion levels) while for high concentrations, the adsorption
efficiency was 92% at the optimum conditions; 0.1 g of the adsorbent
at 150 ppm mercury (II) solution. The adsorption of mercury on
MWCNTs was found to follow the Freundlich adsorption isotherm
and the pseudo-second order kinetic model.
Abstract: Single-phase, high band gap energy Zn0.5Mg0.5O films were grown under oxygen pressure, using pulse laser deposition with a Zn0.5Mg0.5O target. Structural characterization studies revealed that the crystal structures of the ZnX-1MgXO films could be controlled via changes in the oxygen pressure. TEM analysis showed that the thickness of the deposited Zn1-xMgxO thin films was 50–75 nm. As the oxygen pressure increased, we found that one axis of the crystals did not show a very significant increase in the crystallization compared with that observed at low oxygen pressure. The X-ray diffraction peak intensity for the hexagonal-ZnMgO (002) plane increased relative to that for the cubic-ZnMgO (111) plane. The corresponding c-axis of the h-ZnMgO lattice constant increased from 5.141 to 5.148 Å, and the a-axis of the c-ZnMgO lattice constant decreased from 4.255 to 4.250 Å. EDX analysis showed that the Mg content in the mixed-phase ZnMgO films decreased significantly, from 54.25 to 46.96 at.%. As the oxygen pressure was increased from 100 to 150 mTorr, the absorption edge red-shifted from 3.96 to 3.81 eV; however, a film grown at the highest oxygen pressure tested here (200 mTorr).
Abstract: This work investigates the wear of a steam turbine blade coated with titanium nitride (TiN), and compares to the wear of uncoated blades. The coating is deposited on by physical vapor deposition (PVD) method. The working conditions of the blade were simulated and surface temperature and pressure values as well as flow velocity and flow direction were obtained. This data was used in the finite element wear model developed here in order to predict the wear of the blade. The wear mechanisms considered are erosive wear due to particle impingement and fluid jet, and fatigue wear due to repeated impingement of particles and fluid jet. Results show that the life of the TiN-coated blade is approximately 1.76 times longer than the life of the uncoated one.
Abstract: In this study, the Mo-electrode thin films were deposited using two-stepped process and the high purity copper indium selenide-based powder (CuInSe2, CIS) was fabricated by using hydrothermal process by Nanowin Technology Co. Ltd. Because the CIS powder was aggregated into microscale particles, the CIS power was ground into nano-scale particles. 6 wt% CIS particles were mixed and dispersed into isopropyl alcohol (IPA). A new non-vacuum thin-film deposition process, spray coating method (SPM), was investigated to deposit the high-densified CIS absorber layers. 0.1 ml CIS solution was sprayed on the 20 mm×10 mm Mo/glass substrates and then the CuInSe2 thin films were annealed in a selenization furnace using N2 as atmosphere. The annealing temperature and time were set at 550oC and 5 min, and 0.0g~0.6g extra Se content was added in the furnace. The influences of extra Se content on the densification, crystallization, resistivity (ρ), hall mobility (μ), and carrier concentration of the CIS absorber layers were well investigated in this study.
Abstract: In this study, we investigated (In,Ga,Zn)Ox (IGZO) thin films and examined their characteristics of using Ga2O3-2 ZnO (GZO) co-sputtered In2O3 prepared by dual target radio frequency magnetron sputtering at room temperature in a pure Ar atmosphere. RF powers of 80 W and 70 W were used for GZO and pure In2O3, room temperature (RT) was used as deposition temperature, and the deposition time was changed from 15 min to 60 min. Structural, surface, electrical, and optical properties of IGZO thin films were investigated as a function of deposition time. Furthermore, the GZO co-sputtered In2O3 thin films showed a very smooth and featureless surface and an amorphous structure regardless of the deposition time due to the room temperature sputtering process. We would show that the co-sputtered IGZO thin films exhibited transparent electrode properties with high transmittance ratio and low resistivity.
Abstract: The surface properties of many materials can be readily and predictably modified by the controlled deposition of thin layers containing appropriate functional groups and this research area is now a subject of widespread interest. The layer-by-layer (lbl) method involves depositing oppositely charged layers of polyelectrolytes onto the substrate material which are stabilized due to strong electrostatic forces between adjacent layers. This type of modification affords products that combine the properties of the original material with the superficial parameters of the new external layers. Through an appropriate selection of the deposited layers, the surface properties can be precisely controlled and readily adjusted in order to meet the requirements of the intended application. In the presented paper a variety of anionic (poly(acrylic acid)) and cationic (linear poly(ethylene imine), polymers were successfully deposited onto the polypropylene nonwoven using the lbl technique. The chemical structure of the surface before and after modification was confirmed by reflectance FTIR spectroscopy, volumetric analysis and selective dyeing tests. As a direct result of this work, new materials with greatly improved properties have been produced. For example, following a modification process significant changes in the electrostatic activity of a range of novel nanocomposite materials were observed. The deposition of polyelectrolyte nanolayers was found to strongly accelerate the loss of electrostatically generated charges and to increase considerably the thermal resistance properties of the modified fabric (the difference in T50% is over 20oC). From our results, a clear relationship between the type of polyelectrolyte layer deposited onto the flat fabric surface and the properties of the modified fabric was identified.
Abstract: The lignite-fired power plants in the Western Macedonia Lignite Center produce more than 8106 t of fly ash per year. Approximately 90% of this quantity is used for restoration-reclamation of exhausted open-cast lignite mines and slope stabilization of the overburden. The purpose of this work is to evaluate the environmental behavior of the mixture of waste rock and fly ash that is being used in the external deposition site of the South Field lignite mine. For this reason, a borehole was made within the site and 86 samples were taken and subjected to chemical analyses and leaching tests. The results showed very limited leaching of trace elements and heavy metals from this mixture. Moreover, when compared to the limit values set for waste acceptable in inert waste landfills, only few excesses were observed, indicating only minor risk for groundwater pollution. However, due to the complexity of both the leaching process and the contaminant pathway, more boreholes and analyses should be made in nearby locations and a systematic groundwater monitoring program should be implemented both downstream and within the external deposition site.
Abstract: This work deals with heat and mass transfer by steady laminar boundary layer flow of a Newtonian, viscous fluid over a vertical flat plate with variable surface heat flux embedded in a fluid saturated porous medium in the presence of thermophoresis particle deposition effect. The governing partial differential equations are transformed into no-similar form by using special transformation and solved numerically by using an implicit finite difference method. Many results are obtained and a representative set is displaced graphically to illustrate the influence of the various physical parameters on the wall thermophoresis deposition velocity and concentration profiles. It is found that the increasing of thermophoresis constant or temperature differences enhances heat transfer rates from vertical surfaces and increase wall thermophoresis velocities; this is due to favorable temperature gradients or buoyancy forces. It is also found that the effect of thermophoresis phenomena is more pronounced near pure natural convection heat transfer limit; because this phenomenon is directly a temperature gradient or buoyancy forces dependent. Comparisons with previously published work in the limits are performed and the results are found to be in excellent agreement.
Abstract: In the product design and development process, the prototyping or model making is one of the important step to finalize a product which helps in conceptualization of a design. Rapid Prototyping (RP) is layer-by-layer material deposition started during early 1980s with the enormous growth in Computer Aided Design and Manufacturing (CAD/CAM) technologies. The edges and surfaces of a complex solid model and their information are used for defining a product which is further manufactured as a finished product by CNC machining. This paper provides a better platform for researchers, new learners and product manufacturers for various applications of RP models. Subsequently it creates awareness among the peoples of recently developing RP method of manufacturing in product design, developments and its applications.
Abstract: The calcarenites carbonate rocks of the Quaternary ridges, which extend along the northwestern Mediterranean coastal plain of Egypt, represent an excellent model for the transformation of loose sediments to real sedimentary rocks by the different stages of meteoric diagenesis. The depositional and diagenetic fabrics of the rocks, in addition to the strata orientation, highly affect their ultimate compressive strength and other geotechnical properties.
There is a marked increase in the compressive strength (UCS) from the first to the fourth ridge rock samples. The lowest values are related to the loose packing, weakly cemented aragonitic ooid sediments with high porosity, besides the irregularly distributed of cement, which result in decreasing the ability of these rocks to withstand crushing under direct pressure. The high (UCS) values are attributed to the low porosity, the presence of micritic cement, the reduction in grain size and the occurrence of micritization and calcretization processes.
The strata orientation has a notable effect on the measured (UCS). The lowest values have been recorded for the samples cored in the inclined direction; whereas the highest values have been noticed in most samples cored in the vertical and parallel directions to bedding plane. In case of the inclined direction, the bedding planes were oriented close to the plane of maximum shear stress. The lowest and highest anisotropy values have been recorded for the first and the third ridges rock samples, respectively, which may attributed to the relatively homogeneity and well sorted grainstone of the first ridge rock samples, and relatively heterogeneity in grain and pore size distribution and degree of cementation of the third ridge rock samples, besides, the abundance of shell fragments with intraparticle pore spaces, which may produce lines of weakness within the rock.