Abstract: The present study was undertaken to investigate the
effect of aging parameters (time and temperature) on the mechanical
properties of Be-and/or Zr- treated Al-Mg-Zn (7075) alloys. Ultimate
tensile strength, 0.5% offset yield strength and % elongation
measurements were carried out on specimens prepared from cast and
heat treated 7075 alloys containing Be and/or Zr. Different aging
treatment were carried out for the as solution treated (SHT)
specimens (after quenching in warm water). The specimens were
aged at different conditions; Natural and artificial aging was carried
out at room temperature, 120C, 150C, 180C and 220C for different
periods of time. Duplex aging was performed for SHT conditions
(pre-aged at different time and temperature followed by high
temperature aging). Ultimate tensile strength, yield strength and %
elongation data results as a function of different aging parameters are
analysed. A statistical design of experiments (DOE) approach using
fractional factorial design is applied to acquire an understanding of
the effects of these variables and their interactions on the mechanical
properties of Be- and/or Zr- treated 7075 alloys. Mathematical
models are developed to relate the alloy mechanical properties with
the different aging parameters.
Abstract: Physical properties of uranium dinitride (UN2) were
investigated in detail using first principle calculations based on
density functional theory (DFT). To study the strong correlation
effects due to 5f uranium valence electrons, the on-site coulomb
interaction correction U via the Hubbard-like term (DFT+U) was
employed. The UN2 structural, mechanical and thermodynamic
properties were calculated within DFT and Various U of DFT+U
approach.
The Perdew–Burke–Ernzerhof (PBE.5.2) version of the
generalized gradient approximation (GGA) is used to describe the
exchange-correlation with the projector-augmented wave (PAW)
pseudo potentials.
A comparative study shows that results are improved by using the
Hubbard formalism for a certain U value correction like the structural
parameter. For some physical properties the variation versus
Hubbard-U is strong like Young modulus but for others it is weakly
noticeable such as bulk modulus.
We noticed also that from U=7.5 eV, elastic results don’t agree
with the cubic cell because of the C44 values which turn out to be
negative.
Abstract: In this research the effects of adding silica and
alumina nanoparticles on flow ability and compressive strength of
cementitious composites based on Portland cement were investigated.
In the first stage, the rheological behavior of different samples
containing nanosilica, nanoalumina and polypropylene, polyvinyl
alcohol and polyethylene fibers were evaluated. With increasing of
nanoparticles in fresh samples, the slump flow diameter reduced.
Fibers reduced the flow ability of the samples and viscosity
increased. With increasing of the micro silica particles to cement
ratio from 2/1 to 2/2, the slump flow diameter increased. By adding
silica and alumina nanoparticles up to 3% and 2% respectively, the
compressive strength increased and after decreased. Samples
containing silica nanoparticles and fibers had the highest compressive
strength.
Abstract: The aim of this paper is to give an assessment of
environmental effects of IPPC permit conditions of installations that
are in specific territory with high concentration of industrial
activities.
The IPPC permit is the permit that each operator should hold to
operate the installation as stated by the directive 2010/75/UE on
industrial emissions (integrated pollution prevention and control),
known as IED (Industrial Emissions Directive).
The IPPC permit includes all the measures necessary to achieve a
high level of protection of the environment as a whole, also defining
the monitoring requirements as measurement methodology,
frequency and evaluation procedure. The emissions monitoring of a
specific plant may also give indications of the contribution of these
emissions on the air quality of a definite area.
So, it is clear that the IPPC permits are important tools both to
improve the environmental framework and to achieve the air quality
standards, assisting to assess the possible industrial sources
contributions to air pollution.
Abstract: This study is concerned with the optimization of
fermentation parameters for the hyper production of mannanase from
Fusarium oxysporum SS-25 employing two step statistical strategy
and kinetic characterization of crude enzyme preparation. The
Plackett-Burman design used to screen out the important factors in
the culture medium revealed 20% (w/w) wheat bran, 2% (w/w) each
of potato peels, soyabean meal and malt extract, 1% tryptone, 0.14%
NH4SO4, 0.2% KH2PO4, 0.0002% ZnSO4, 0.0005% FeSO4, 0.01%
MnSO4, 0.012% SDS, 0.03% NH4Cl, 0.1% NaNO3 in brewer’s spent
grain based medium with 50% moisture content, inoculated with
2.8×107 spores and incubated at 30oC for 6 days to be the main
parameters influencing the enzyme production. Of these factors, four
variables including soyabean meal, FeSO4, MnSO4 and NaNO3 were
chosen to study the interactive effects and their optimum levels in
central composite design of response surface methodology with the
final mannanase yield of 193 IU/gds. The kinetic characterization
revealed the crude enzyme to be active over broader temperature and
pH range. This could result in 26.6% reduction in kappa number with
4.93% higher tear index and 1% increase in brightness when used to
treat the wheat straw based kraft pulp. The hydrolytic potential of
enzyme was also demonstrated on both locust bean gum and guar
gum.
Abstract: The progress of industry integrated circuits in recent
years has been pushed by continuous miniaturization of transistors.
With the reduction of dimensions of components at 0.1 micron and
below, new physical effects come into play as the standard simulators
of two dimensions (2D) do not consider. In fact the third dimension
comes into play because the transverse and longitudinal dimensions
of the components are of the same order of magnitude. To describe
the operation of such components with greater fidelity, we must
refine simulation tools and adapted to take into account these
phenomena. After an analytical study of the static characteristics of
the component, according to the different operating modes, a
numerical simulation is performed of field-effect transistor with
submicron gate MESFET GaInP. The influence of the dimensions of
the gate length is studied. The results are used to determine the
optimal geometric and physical parameters of the component for their
specific applications and uses.
Abstract: Vegetation affects the mean and turbulent flow
structure. It may increase flood risks and sediment transport.
Therefore, it is important to develop analytical approaches for the bed
shear stress on vegetated bed, to predict resistance caused by
vegetation. In the recent years, experimental and numerical models
have both been developed to model the effects of submerged
vegetation on open-channel flow. In this paper, different analytic
models are compared and tested using the criteria of deviation, to
explore their capacity for predicting the mean velocity and select the
suitable one that will be applied in real case of rivers. The
comparison between the measured data in vegetated flume and
simulated mean velocities indicated, a good performance, in the case
of rigid vegetation, whereas, Huthoff model shows the best
agreement with a high coefficient of determination (R2=80%) and the
smallest error in the prediction of the average velocities.
Abstract: The present work aims to throw light on the effects of
arcing in air on the surface state of contact pastilles made of silvernickel
Ag-Ni (60/40). Also, the photoelectric emission from these
electrical contacts has been investigated in the spectral range of 196-
256 nm. In order to study the effects of arcing on the EWF, the
metallic samples were subjected to electrical arcs in air, at
atmospheric pressure and room temperature, after that, they have
been introduced into the vacuum chamber of an experimental UHV
set-up for EWF measurements. Both Fowler method of isothermal
curves and linearized Fowler plots were used for the measurement of
the EWF by the photoelectric effect.
It has been found that the EWF varies with the number of applied
arcs. Thus, after 500 arcs in air, the observed EWF increasing is
probably due to progressive inclusion of oxide on alloy surface.
Microscopic examination is necessary to get better understandings on
EWF of silver alloys, for both virgin and arced electrical contacts.
Abstract: Background: With the perceived pain and poor
function experienced following knee arthroplasty, patients usually
feel un-satisfied. Yet, a controversy still persists on the appropriate
operative technique that doesn’t affect proprioception much.
Purpose: This study compared the effects of Cruciate Retaining
(CR) and Posterior Stabilized (PS) total knee arthroplasty (TKA on
dynamic balance, pain and functional performance following
rehabilitation.
Methods: Thirty patients with CRTKA (group I), thirty with
PSTKA (group II) and fifteen indicated for arthroplasty but weren’t
operated on yet (group III) participated in the study. The mean age
was 54.53±3.44, 55.13±3.48 and 55.33±2.32 years and BMI
35.7±3.03, 35.7±1.99 and 35.73±1.03 kg/m2 for groups I, II and III
respectively. The Berg Balance Scale (BBS), WOMAC pain subscale
and Timed Up-and-Go (TUG) and Stair-Climbing (SC) tests were
used for assessment. Assessments were conducted four weeks preand
post-operatively, three, six and twelve months post-operatively
with the control group being assessed at the same time intervals. The
post-operative rehabilitation involved hospitalization (1st week),
home-based (2nd-4th weeks), and outpatient clinic (5th-12th weeks)
programs, follow-up to all groups for twelve months.
Results: The Mixed design MANOVA revealed that group I had
significantly lower pain scores and SC time compared with group II
three, six and twelve months post-operatively. Moreover, the BBS
scores increased significantly and the pain scores and TUG and SC
time decreased significantly six months post-operatively compared
with four weeks pre- and post-operatively and three months postoperatively
in groups I and II with the opposite being true four weeks
post-operatively. But no significant differences in BBS scores, pain
scores and TUG and SC time between six and twelve months postoperatively
in groups I and II.
Interpretation/Conclusion: CRTKA is preferable to PSTKA,
possibly due to the preserved human proprioceptors in the un-excised
PCL.
Abstract: A parametric study on circular thin-walled pipes
subjected to pure bending is performed. Both straight and curved
pipes are considered. Ratio D/t, initial pipe curvature and internal
pressure are the parameters varying in the analyses. The study is
mainly FEA-based.
It is found that negative curvatures (opposite to bending moment)
considerably increase stiffness and buckling limit of the pipe when no
internal pressure is acting and, similarly, positive curvatures decrease
the stiffness and buckling limit. For internal pressurised pipes the
effects of initial pipe curvature are less relevant. Results show that
this phenomenon is in relationship with the cross-section deformation
due to bending moment, which undergoes relevant ovalisation for no
pressurised pipes and little ovalisation for pressurised pipes.
Abstract: The present study was undertaken to investigate the
effect of pre-aging and aging parameters (time and temperature) on
the mechanical properties of Al-Mg-Zn (7075) alloys. Ultimate
tensile strength, 0.5% offset yield strength and % elongation
measurements were carried out on specimens prepared from cast and
heat treated 7075 alloys. Aging treatments were carried out for the as
solution treated (SHT) specimens (after quenching in warm water).
The specimens were aged at different conditions; Natural aging was
carried out at room temperature for different periods of time. Double
aging was performed for SHT conditions (pre-aged at different time
and temperature followed by high temperature aging). Ultimate
tensile strength, yield strength and % elongation as a function of
different pre-aging and aging parameters are analyzed to acquire an
understanding of the effects of these variables and their interactions
on the mechanical properties of Be-treated 7075 alloys.
Abstract: The mechanics of rip currents are complex, involving
interactions between waves, currents, water levels and the bathymetry,
that present particular challenges for numerical models. Here,
the effects of a grid-spacing dependent horizontal mixing on the
wave-current interactions are studied. Near the shore, wave rays
diverge from channels towards bar crests because of refraction by
topography and currents, in a way that depends on the rip current
intensity which is itself modulated by the horizontal mixing. At
low resolution with the grid-spacing dependent horizontal mixing,
the wave motion is the same for both coupling modes because the
wave deviation by the currents is weak. In high resolution case,
however, classical results are found with the stabilizing effect of
the flow by feedback of waves on currents. Lastly, wave-current
interactions and the horizontal mixing strongly affect the intensity
of the three-dimensional rip velocity.
Abstract: Fracture in hot precision forging of engine valves was
investigated in this paper. The entire valve forging procedure was
described and the possible cause of the fracture was proposed. Finite
Element simulation was conducted for the forging process, with
commercial Finite Element code DEFORMTM. The effects of
material properties, the effect of strain rate and temperature were
considered in the FE simulation. Two fracture criteria were discussed
and compared, based on the accuracy and reliability of the FE
simulation results. The selected criterion predicted the fracture
location and shows the trend of damage increasing with good
accuracy, which matches the experimental observation. Additional
modification of the punch shapes was proposed to further reduce the
tendency of fracture in forging. Finite Element comparison shows a
great potential of such application in the mass production.
Abstract: The absorption power generation cycle based on the
ammonia-water mixture has attracted much attention for efficient
recovery of low-grade energy sources. In this paper a thermodynamic
performance analysis is carried out for a Kalina cycle using
ammonia-water mixture as a working fluid for efficient conversion of
low-temperature heat source in the form of sensible energy. The
effects of the source temperature on the system performance are
extensively investigated by using the thermodynamic models. The
results show that the source temperature as well as the ammonia mass
fraction affects greatly on the thermodynamic performance of the
cycle.
Abstract: In this work, we study the behavior of introducing
atomic size vacancy in a graphene nanoribbon superlattice. Our
investigations are based on the density functional theory (DFT) with
the Local Density Approximation in Atomistix Toolkit (ATK). We
show that, in addition to its shape, the position of vacancy has a
major impact on the electrical properties of a graphene nanoribbon
superlattice. We show that the band gap of an armchair graphene
nanoribbon may be tuned by introducing an appropriate periodic
pattern of vacancies. The band gap changes in a zig-zag manner
similar to the variation of band gap of a graphene nanoribbon by
changing its width.
Abstract: The study is a review of the literature concerning the
consequences of non-standard monetary policy, which are used by
central banks during unconventional periods, threatening banking
sector instability. In particular, the attention was paid to the effects of
non-standard monetary policy tools for financial markets. However,
the empirical evidence about their effects and real consequences for
financial markets is still not final. The main aim of the study is to
survey consequences of standard and non-standard monetary policy
instruments, implemented during the global financial crisis in the
United States, United Kingdom and euro area, with particular
attention to the results for the stabilization of global financial
markets. The study consists mainly of the empirical review,
indicating the impact of the implementation of these tools for
financial markets. The following research methods were used in the
study: literature studies, including domestic and foreign literature,
cause and effect analysis and statistical analysis.
Abstract: Background and aim: It has not been well studied
whether fentanyl-thiopental (FT) is effective and safe for PSA in
orthopedic procedures in Emergency Department (ED). The aim of
this trial was to evaluate the effectiveness of intravenous FT versus
fentanyl-midazolam (FM) in patients who suffered from shoulder
dislocation or distal radial fracture-dislocation.
Methods: In this randomized double-blinded study, Seventy-six
eligible patients were entered the study and randomly received
intravenous FT or FM. The success rate, onset of action and recovery
time, pain score, physicians’ satisfaction and adverse events were
assessed and recorded by treating emergency physicians. The
statistical analysis was intention to treat.
Results: The success rate after administrating loading dose in FT
group was significantly higher than FM group (71.7% vs. 48.9%,
p=0.04); however, the ultimate unsuccessful rate after 3 doses of
drugs in the FT group was higher than the FM group (3 to 1) but it
did not reach to significant level (p=0.61). Despite near equal onset
of action time in two study group (P=0.464), the recovery period in
patients receiving FT was markedly shorter than FM group
(P
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: Shortfall of electrical energy in Pakistan is a challenge
adversely affecting its industrial output and social growth. As
elsewhere, Pakistan derives its electrical energy from a number of
conventional sources. The exhaustion of petroleum and conventional
resources, the rising costs coupled with extremely adverse climatic
effects are taking its toll especially on the under-developed countries
like Pakistan. As alternate, renewable energy sources like hydropower,
solar, wind, even bio-energy and a mix of some or all of them
could provide a credible alternative to the conventional energy
resources that would not only be cleaner but sustainable as well. As a
model, solar energy-based power grid for the near future has been
attempted to offset the energy shortfalls as a mix with our existing
sustainable natural energy resources. An assessment of solar energy
potential for electricity generation is being presented for fulfilling the
energy demands with higher level of reliability and sustainability.
This model is based on the premise that solar energy potential of
Pakistan is not only reliable but also sustainable. This research
estimates the present & future approaching renewable energy
resource specially the impact of solar energy based power grid for
mitigating energy shortage in Pakistan.
Abstract: The thyroid gland is the largest classic endocrine
organ that effects many organs of the body and plays a significant
role in the process of Metabolism in animals. The aim of this study
was to investigate the prevalence of thyroid disorders diagnosed by
ultrasound and microscopic Lesions of the thyroid during the
slaughter of apparently healthy One Humped Camels (Camelus
dromedarius) in Iran. Randomly, 520 male camels (With an age
range of 4 to 8 years), were studied in 2012 to 2013. The Camels’
thyroid glands were evaluated by sonographic examination. In both
longitudinal and transverse view and then tissue sections were
provide and stained with H & E and finally examined by light
microscopy. The results obtained indicated the following:
hyperplastic goiter (21%), degenerative changes (12%), follicular
cysts (8%), follicular atrophy (4%), nodular hyperplasia (3%),
adenoma (1%), carcinoma (1%) and simple goiter colloid (1%).
Ultrasound evaluation of thyroid gland in adenoma and carcinoma
showed enlargement and irregular of the gland, decreased
echogenicity, and the heterogeneous thyroid parenchyma. Also, in
follicular cysts were observed in the enlarged gland with no echo
structures of different sizes and decreased echogenicity as a local or
general. In nodular hyperplasia, increase echogenicity and
heterogeneous parenchymal were seen. These findings suggest the
use of sonography and pathology as a screening test in the diagnosis
of complications of thyroid disorders.