Abstract: An unconventional composite inorganic ceramic
membrane capable of enhancing carbon dioxide emission decline was
fabricated and tested at laboratory scale in conformism to various
environmental guidelines and also to mitigate the effect of global
warming. A review of the existing membrane technologies for carbon
capture including the relevant gas transport mechanisms is presented.
Single gas permeation experiments using silica modified ceramic
membrane with internal diameter 20mm, outside diameter 25mm and
length of 368mm deposited on a macro porous support was carried
out to investigate individual gas permeation behaviours at different
pressures at room temperature. Membrane fabrication was achieved
using after a dip coating method. Nitrogen, Carbon dioxide, Argon,
Oxygen and Methane pure gases were used to investigate their
individual permeation rates at various pressures. Results show that
the gas flow rate increases with pressure drop. However above a
pressure of 3bar, CO2 permeability ratio to that of the other gases
indicated control of a more selective surface adsorptive transport
mechanism.
Abstract: In this research numerical simulations are performed,
using the multi-relaxation-time lattice Boltzmann method, in the
range 3 ≤ β = w[d] ≤ 30 at Re = 100, 200 and 300, where β the
blockage ratio, w is the equispaced distance between centers of
cylinders, d is the diameter of the cylinder and Re is the Reynolds
number, respectively. Special attention is paid to the effect of the
equispaced distance between centers of cylinders. Visualization of
the vorticity contour visualization are presented for some simulation
showing the flow dynamics and patterns for blockage effect. Results
show that the drag and mean drag coefficients, and Strouhal number,
in general, decrease with the increase of β for fixed Re. It is found
that the decreasing rate of drag and mean drag coefficients and
Strouhal number is more distinct in the range 3 ≤ β ≤ 15. We found
that when β > 15, the blockage effect almost diminishes. Our results
further indicate that the drag and mean drag coefficients, peak value
of the lift coefficient, root-mean-square value of the lift and drag
coefficients and the ratio between lift and drag coefficients decrease
with the increase of Re. The results indicate that symmetry boundary
condition have more blockage effect as compared to periodic
boundary condition.
Abstract: One of the main challenges in using the Discrete
Element Method (DEM) is to specify the correct input parameter
values. In general, the models are sensitive to the input parameter
values and accurate results can only be achieved if the correct values
are specified. For the linear contact model, micro-parameters such as
the particle density, stiffness, coefficient of friction, as well as the
particle size and shape distributions are required. There is a need for
a procedure to accurately calibrate these parameters before any
attempt can be made to accurately model a complete bulk materials
handling system. Since DEM is often used to model applications in
the mining and quarrying industries, a calibration procedure was
developed for materials that consist of relatively large (up to 40 mm
in size) particles. A coarse crushed aggregate was used as the test
material. Using a specially designed large shear box with a diameter
of 590 mm, the confined Young’s modulus (bulk stiffness) and
internal friction angle of the material were measured by means of the
confined compression test and the direct shear test respectively. DEM
models of the experimental setup were developed and the input
parameter values were varied iteratively until a close correlation
between the experimental and numerical results was achieved. The
calibration process was validated by modelling the pull-out of an
anchor from a bed of material. The model results compared well with
experimental measurement.
Abstract: This work sets out to debate the tensions involved in
the processes of contamination and self-purification in the urban
space, particularly in the streams that run through the Buenos Aires
metropolitan area. For much of their course, those streams are piped;
their waters do not come into contact with the outdoors until they
have reached deeply impoverished urban areas with high levels of
environmental contamination. These are peripheral zones that, until
thirty years ago, were marshlands and fields. They are now densely
populated areas largely lacking in urban infrastructure.
The Cárcova neighborhood, where this project is underway, is in
the José León Suárez section of General San Martín county, Buenos
Aires province. A stretch of José León Suarez canal crosses the
neighborhood. Starting upstream, this canal carries pollutants due to
the sewage and industrial waste released into it. Further downstream,
in the neighborhood, domestic drainage is poured into the stream. In
this paper, we formulate a hypothesis diametrical to the one that
holds that these neighborhoods are the primary source of
contamination, suggesting instead that in the stretch of the canal that
runs through the neighborhood the stream’s waters are actually
cleaned and the sediments accumulate pollutants. Indeed, the
stretches of water that runs through these neighborhoods act as water
processing plants for the metropolis.
This project has studied the different organic-load polluting
contributions to the water in a certain stretch of the canal, the
reduction of that load over the course of the canal, and the
incorporation of pollutants into the sediments. We have found that
the surface water has considerable ability to self-purify, mostly due to
processes of sedimentation and adsorption. The polluting load is
accumulated in the sediments where that load stabilizes slowly by
means of anaerobic processes. In this study, we also investigated the
risks of sediment management and the use of the processes studied
here in controlled conditions as tools of environmental restoration.
Abstract: The model tests were conducted in the laboratory
without and with Plastic recycled polymer in fly ash steep slopes
overlaying soft foundation soils like fly ash and powai soil in order to
check the stability of steep slope. In this experiment, fly ash is used
as a filling material and Plastic Recycled Polymers of diameter =
3mm and length = 4mm were made from waste plastic product (lower
grade plastic product). The properties of fly ash and Plastic recycled
polymers are determined. From the experiments, load and settlement
have measured. From these data, load –settlement curves have
reported. It has been observed from test results that load carrying
capacity of mixture fly ash with Plastic Recycled Polymers slope is
more than that of fly ash slope. The deformation of Plastic Recycled
Polymers slope is slightly more than that of fly ash slope. A Finite
Element Method (F.E.M.) was also evaluated using PLAXIS 3D
version. The failure pattern, deformations and factor of safety are
reported based on analytical programme. The results from
experimental data and analytical programme are compared and
reported.
Abstract: In the present work, Electrochemical Impedance
Spectrocopy (EIS) is applied to study the transport of different metal
cations through a cation-exchange membrane. This technique enables
the identification of the ionic-transport characteristics and to
distinguish between different transport mechanisms occurring at
different current density ranges. The impedance spectra are
dependent on the applied dc current density, on the type of cation and
on the concentration.
When the applied dc current density increases, the diameter of the
impedance spectra loops increases because all the components of
membrane system resistance increase. The diameter of the impedance
plots decreases in the order of Na(I), Ni(II) and Cr(III) due to the
increased interactions between the negatively charged sulfonic
groups of the membrane and the cations with greater charge. Nyquist
plots are shifted towards lower values of the real impedance, and its
diameter decreases with the increase of concentration due to the
decrease of the solution resistance.
Abstract: We proposed a Hyperbolic Gompertz Growth Model
(HGGM), which was developed by introducing a shape parameter
(allometric). This was achieved by convoluting hyperbolic sine
function on the intrinsic rate of growth in the classical gompertz
growth equation. The resulting integral solution obtained
deterministically was reprogrammed into a statistical model and used
in modeling the height and diameter of Pines (Pinus caribaea). Its
ability in model prediction was compared with the classical gompertz
growth model, an approach which mimicked the natural variability of
height/diameter increment with respect to age and therefore provides
a more realistic height/diameter predictions using goodness of fit
tests and model selection criteria. The Kolmogorov Smirnov test and
Shapiro-Wilk test was also used to test the compliance of the error
term to normality assumptions while the independence of the error
term was confirmed using the runs test. The mean function of top
height/Dbh over age using the two models under study predicted
closely the observed values of top height/Dbh in the hyperbolic
gompertz growth models better than the source model (classical
gompertz growth model) while the results of R2, Adj. R2, MSE and
AIC confirmed the predictive power of the Hyperbolic Gompertz
growth models over its source model.
Abstract: Transmission shafts are affected by various forces, for
example, during acceleration or sudden breaks, bending during
transportation, vertical forces that lead to cuts. One of the main
failures in combines is breaking shaft which repairmen refer it.
Structural resistance of canal against torque is very important in the
beginning of the movement. For analyzing stress, a typical sample
from a type of combine was selected, called JD955 combine. Long
shaft in this combine was analyzed with finite element method by
Ansys13 generic package under static load. Conducted analysis
showed that there is a maximum stress in contact surfaces of
indentations and also in place of changing diameter. Safety factor
value is low in parts of the shaft and this increases the probability of
failure at these points. To improve the conditions with the least cost
and an approach of product improvement, using alternative alloy is
important.
Abstract: The Aptima® HIV-1 Quant Dx Assay is a fully
automated assay on the Panther system. It is based on Transcription-
Mediated Amplification and real time detection technologies. This
assay is intended for monitoring HIV-1 viral load in plasma
specimens and for the detection of HIV-1 in plasma and serum
specimens.
Nine-hundred and seventy nine specimens selected at random
from routine testing at St Thomas’ Hospital, London were
anonymised and used to compare the performance of the Aptima
HIV-1 Quant Dx assay and Roche COBAS® AmpliPrep/COBAS®
TaqMan® HIV-1 Test, v2.0. Two-hundred and thirty four specimens
gave quantitative HIV-1 viral load results in both assays. The
quantitative results reported by the Aptima Assay were comparable to
those reported by the Roche COBAS AmpliPrep/COBAS TaqMan
HIV-1 Test, v2.0 with a linear regression slope of 1.04 and an
intercept on -0.097.
The Aptima assay detected HIV-1 in more samples than the
COBAS assay. This was not due to lack of specificity of the Aptima
assay because this assay gave 99.83% specificity on testing plasma
specimens from 600 HIV-1 negative individuals. To understand the
reason for this higher detection rate a side-by-side comparison of low
level panels made from the HIV-1 3rd international standard
(NIBSC10/152) and clinical samples of various subtypes were tested
in both assays. The Aptima assay was more sensitive than the
COBAS assay.
The good sensitivity, specificity and agreement with other
commercial assays make the HIV-1 Quant Dx Assay appropriate for
both viral load monitoring and detection of HIV-1 infections.
Abstract: In this study, ultrasonic assisted machining (UAM) technique is applied in side-surface milling experiment for glass-ceramic workpiece material. The tungsten carbide cutting-tool with diamond coating is used in conjunction with two kinds of cooling/lubrication mediums such as water-soluble (WS) cutting fluid and minimum quantity lubricant (MQL). Full factorial process parameter combinations on the milling experiments are planned to investigate the effect of process parameters on cutting performance. From the experimental results, it tries to search for the better process parameter combination which the edge-indentation and the surface roughness are acceptable. In the machining experiments, ultrasonic oscillator was used to excite a cutting-tool along the radial direction producing a very small amplitude of vibration frequency of 20KHz to assist the machining process. After processing, toolmaker microscope was used to detect the side-surface morphology, edge-indentation and cutting tool wear under different combination of cutting parameters, and analysis and discussion were also conducted for experimental results. The results show that the main leading parameters to edge-indentation of glass ceramic are cutting depth and feed rate. In order to reduce edge-indentation, it needs to use lower cutting depth and feed rate. Water-soluble cutting fluid provides a better cooling effect in the primary cutting area; it may effectively reduce the edge-indentation and improve the surface morphology of the glass ceramic. The use of ultrasonic assisted technique can effectively enhance the surface finish cleanness and reduce cutting tool wear and edge-indentation.
Abstract: Cesium iodide (CsI) melt was injected into anodic aluminum oxide (AAO) template and was solidified to CsI column. The controllable AAO channel size (10~500 nm) can makes CsI column size from 10 to 500 nm in diameter. In order to have a shorter light irradiate from each singe CsI column top to bottom the AAO template was coated a TiO2 nano-film. The TiO2 film acts a refraction film and makes X-ray has a shorter irradiation path in the CsI crystal making a stronger the photo-electron signal. When the incidence light irradiate from air (R=1.0) to CsI’s first surface (R=1.84) the first refraction happen, the first refraction continue into TiO2 film (R=2.88) and produces the low angle of the second refraction. Then the second refraction continue into AAO wall (R=1.78) and produces the third refraction after refractions between CsI and AAO wall (R=1.78) produce the fourth refraction. The incidence light through TiO2 filmand the first surface of CsI then arrive to the second surface of CsI. Therefore, the TiO2 film can has shorter refraction path of incidence light and increase the photo-electron conversion efficiency.
Abstract: In this research the effect of moisture at three levels
(47, 57, and 67 w.b.%) on the physical properties of the Pofaki pea
variety including, dimensions, geometric mean diameter, volume,
sphericity index and the surface area was determined. The influence
of different moisture levels (47, 57 and 67 w.b.%), in two loading
orientation (longitudinal and transverse) and three loading speed (4,6
and 8 mm min-1) on the mechanical properties of pea such as
maximum deformation, rupture force, rupture energy, toughness and
the power to break the pea was investigated. It was observed in the
physical properties that moisture changes were affective at 1% on,
dimensions, geometric mean diameter, volume, sphericity index and
the surface area. It was observed in the mechanical properties that
moisture changes were effective at 1% on, maximum deformation,
rupture force, rupture energy, toughness and the power to break.
Loading speed was effective on maximum deformation, rupture
force, rupture energy at 1% and it was effective on toughness at 5%.
Loading orientation was effective on maximum deformation, rupture
force, rupture energy, toughness at 1% and it was effective on power
at 5%. The mutual effect of speed and orientation were effective on
rupture energy at 1% and were effective on toughness at 5%
probability. The mutual effect of moisture and speed were effective
on rupture force and rupture energy at 1% and were effective on
toughness 5% probability. The mutual effect of orientation and
moisture on rupture energy and toughness were effective at 1%.
Abstract: This paper deals with the theoretical and numerical
investigation of magneto hydrodynamic boundary layer flow of a
nanofluid past a wedge shaped wick in heat pipe used for the cooling
of electronic components and different type of machines. To
incorporate the effect of nanoparticle diameter, concentration of
nanoparticles in the pure fluid, nanothermal layer formed around the
nanoparticle and Brownian motion of nanoparticles etc., appropriate
models are used for the effective thermal and physical properties of
nanofluids. To model the rotation of nanoparticles inside the base
fluid, microfluidics theory is used. In this investigation ethylene
glycol (EG) based nanofluids, are taken into account. The non-linear
equations governing the flow and heat transfer are solved by using a
very effective particle swarm optimization technique along with
Runge-Kutta method. The values of heat transfer coefficient are
found for different parameters involved in the formulation viz.
nanoparticle concentration, nanoparticle size, magnetic field and
wedge angle etc. It is found that, the wedge angle, presence of
magnetic field, nanoparticle size and nanoparticle concentration etc.
have prominent effects on fluid flow and heat transfer characteristics
for the considered configuration.
Abstract: In emerging economies, recycling is an opportunity
for the cities to increase the lifespan of sanitary landfills, reduce the
costs of the solid waste management, decrease the environmental
problems of the waste treatment through reincorporate waste in the
productive cycle and protect and develop people’s livelihoods of
informal waste pickers. However, few studies have analysed the
possibilities and strategies to integrate formal and informal sectors in
the solid waste management for the benefit of both. This study seek
to make a strength, weakness, opportunity, and threat (SWOT)
analysis in three recycling associations of Bogotá with the aim to
understand and determine the situation of recycling from perspective
of informal sector in its transition to enter as authorized waste
providers. Data used in the analysis are derived from multiple
strategies such as literature review, the Bogota’s recycling database,
focus group meetings, governmental reports, national laws and
regulations and specific interviews with key stakeholders. Results of
this study show as the main stakeholders of formal and informal
sector of waste management can identify the internal and internal
conditions of recycling in Bogotá. Several strategies were designed
based on the SWOTs determined, could be useful for Bogotá to
advance and promote recycling as a key strategy for integrated
sustainable waste management in the city.
Abstract: This paper presents a model for a modified T-junction
device for microspheres generation. The numerical model is
developed using a commercial software package: COMSOL
Multiphysics. In order to test the accuracy of the numerical model,
multiple variables, such as the flow rate of cross-flow, fluid properties,
structure, and geometry of the microdevice are applied. The results
from the model are compared with the experimental results in the
diameter of the microsphere generated. The comparison shows a good
agreement. Therefore the model is useful in further optimization of the
device and feedback control of microsphere generation if any.
Abstract: Forward Osmosis (FO) polyamide thin-film composite
membranes have been prepared by interfacial polymerization using
commercial UF polyethersulfoneas membrane support. Different
interfacial polymerization times (10s, 30s and 60s) in the organic
solution containing trimesoyl chloride (TMC) at constant m-phenylenediamine
(MPD) concentration (2% w/v) were studied. The
synthesized polyamide membranes then tested for treatment of
natural organic matter (NOM) and compared to commercial Cellulose
TriAcetate (CTA) membrane. It was found that membrane prepared
with higher reaction time (30s and 60s) exhibited better membrane
performance (flux and humic acid removal) over commercial CTA
membrane.
Abstract: Nanofibers of PVA /nickel nitrate/silica/alumina
izopropoxide/boric acid composite were prepared by using sol-gel
processing and electrospinning technique. By high temperature
calcinations of the above precursor fibers, nanofibers of
NiO/Al2O3/B2O3/SiO2 composite with diameters about 500 nm
could be successfully obtained. The fibers were characterized by
XRD and SEM analyses.
Abstract: Non-water based fixed abrasive polishing was adopted
to manufacture LBO crystal for nano precision surface quality because
of its deliquescent. Ethyl alcohol was selected as the non-water based
slurry solvent and ethanediamine, lactic acid, hydrogen peroxide was
added in the slurry as a chemical additive, respectively. Effect of
different additives with non-water based slurry on material removal
rate, surface topography, microscopic appearances, and surface
roughness were investigated in fixed abrasive polishing of LBO
crystal. The results show the best surface quality of LBO crystal with
surface roughness Sa 8.2 nm and small damages was obtained by
non-water based slurry with lactic acid. Non-water based fixed
abrasive polishing can achieve nano precision surface quality of LBO
crystal with high material removal.
Abstract: This article presents modeling studies of NiAl alloy
under solid-particle erosion and liquid-drop erosion. In the
solid-particle erosion simulation, attention is paid to the oxide scale
thickness variation on the alloy in high-temperature erosion
environments. The erosion damage is assumed to be deformation wear
and cutting wear mechanisms, incorporating the influence of the oxide
scale on the eroded surface; thus the instantaneous oxide thickness is
the result of synergetic effect of erosion and oxidation. For liquid-drop
erosion, special interest is in investigating the effects of drop velocity
and drop size on the damage of the target surface. The models of
impact stress wave, mean depth of penetration, and maximum depth of
erosion rate (Max DER) are employed to develop various maps for
NiAl alloy, including target thickness vs. drop size (diameter), rate of
mean depth of penetration (MDRP) vs. drop impact velocity, and
damage threshold velocity (DTV) vs. drop size.
Abstract: In this study, polycaprolactone (PCL) was dissolved
in chloroform:ethanol solvent system at a concentration of 18 w/v %.
1, 2, 4, and 6 droplets of formic acid were added to the prepared 10ml
PCL-chloroform:ethanol solutions separately. Fibrous webs were
produced by electrospinning technique based on the horizontal
working principle. Morphology of the webs was investigated by
using scanning electron microscopy (SEM) whereas fiber diameters
were measured by Image J Software System. The effect of formic
acid addition to the mostly used chloroform solvent on fiber
morphology was examined.
Results indicate that there is a distinct fall in fiber diameter with
the addition of formic acid drops. The average fiber diameter was
measured as 2.22μm in PCL /chloroform:ethanol solution system. On
the other hand, 328nm and 256 nm average fiber diameters were
measured for the samples of 4 drops and 6 drops formic acid added.
This study offers alternative solvent systems to produce nanoscaled,
nontoxic PCL fibrous webs by electrospinning technique.