Abstract: Knowledge of bone mechanical properties is important
for bone substitutes design and fabrication, and more efficient
prostheses development. The aim of this study is to characterize the
viscoelastic behavior of bone specimens, through stress relaxation
and fatigue tests performed to trabecular bone samples from bovine
femoral heads. Relaxation tests consisted on preloading the samples
at five different magnitudes and evaluate them for 1020 seconds,
adjusting the results to a KWW mathematical model. Fatigue tests
consisted of 700 load cycles and analyze their status at the end of the
tests. As a conclusion we have that between relaxation stress and
each preload there is linear relation and for samples with initial
Young´s modulus greater than 1.5 GPa showed no effects due fatigue
test loading cycles.
Abstract: Steady three-dimensional and two free surface waves
generated by moving bodies are presented, the flow problem to be
simulated is rich in complexity and poses many modeling challenges
because of the existence of breaking waves around the ship hull, and
because of the interaction of the two-phase flow with the turbulent
boundary layer. The results of several simulations are reported. The
first study was performed for NACA0012 of hydrofoil with different
meshes, this section is analyzed at h/c= 1, 0345 for 2D. In the second
simulation a mathematically defined Wigley hull form is used to
investigate the application of a commercial CFD code in prediction of
the total resistance and its components from tangential and normal
forces on the hull wetted surface. The computed resistance and wave
profiles are used to estimate the coefficient of the total resistance for
Wigley hull advancing in calm water under steady conditions. The
commercial CFD software FLUENT version 12 is used for the
computations in the present study. The calculated grid is established
using the code computer GAMBIT 2.3.26. The shear stress k-ωSST
model is used for turbulence modeling and the volume of fluid
technique is employed to simulate the free-surface motion. The
second order upwind scheme is used for discretizing the convection
terms in the momentum transport equations, the Modified HRIC
scheme for VOF discretization. The results obtained compare well
with the experimental data.
Abstract: Steady three-dimensional and two free surface waves
generated by moving bodies are presented, the flow problem to be
simulated is rich in complexity and poses many modeling challenges
because of the existence of breaking waves around the ship hull, and
because of the interaction of the two-phase flow with the turbulent
boundary layer. The results of several simulations are reported. The
first study was performed for NACA0012 of hydrofoil with different
meshes, this section is analyzed at h/c= 1, 0345 for 2D. In the second
simulation a mathematically defined Wigley hull form is used to
investigate the application of a commercial CFD code in prediction of
the total resistance and its components from tangential and normal
forces on the hull wetted surface. The computed resistance and wave
profiles are used to estimate the coefficient of the total resistance for
Wigley hull advancing in calm water under steady conditions. The
commercial CFD software FLUENT version 12 is used for the
computations in the present study. The calculated grid is established
using the code computer GAMBIT 2.3.26. The shear stress k-ωSST
model is used for turbulence modeling and the volume of fluid
technique is employed to simulate the free-surface motion. The
second order upwind scheme is used for discretizing the convection
terms in the momentum transport equations, the Modified HRIC
scheme for VOF discretization. The results obtained compare well
with the experimental data.
Abstract: Paranoid ideation is a common thought process that
constitutes a defense against perceived social threats. The current
study aimed at the characterization of paranoid ideation in youths and
to explore the possible predictors involved in the development of
paranoid ideations. Paranoid ideation, shame, submission, early
childhood memories and current depressive, anxious and stress
symptomatology were assessed in a sample of 1516 Portuguese
youths. Higher frequencies of paranoid ideation were observed,
particularly in females and youths from lower socioeconomic status.
The main predictors identified relates to submissive behaviors and
adverse childhood experiences, and especially to shame feelings. The
current study emphasizes that the these predictors are similar to
findings in adults and clinical populations, and future implications to
research and clinical practice aiming at paranoid ideations are
discussed, as well as the pertinence of the study of mediating factors
that allow a wider understanding of this thought process in younger
populations and the prevention of psychopathology in adulthood.
Abstract: This study focuses on a novel method for dispersion
and distribution of reinforcement under high intensive shear stress to
produce metal composites. The polyacrylonitrile (PAN)-based short
carbon fiber (Csf) and Nextel 610 alumina fiber were dispersed under
high intensive shearing at mushy zone in semi-solid of A356 by a
novel method. The bundles and clusters were embedded by
infiltration of slurry into the clusters, thus leading to a uniform
microstructure. The fibers were embedded homogenously into the
aluminum around 576-580°C with around 46% of solid fraction.
Other experiments at 615°C and 568°C which are contained 0% and
90% solid respectively were not successful for dispersion and
infiltration of aluminum into bundles of Csf. The alumina fiber has
been cracked by high shearing load. The morphologies and
crystalline phase were evaluated by SEM and XRD. The adopted
thixo-process effectively improved the adherence and distribution of
Csf into Al that can be developed to produce various composites by
thixomixing.
Abstract: This paper presents the results of an experimental
study undertaken to evaluate the local bond stress-slip response of
short embedment of reinforcing bars in normal concrete (NC) and
high performance fiber reinforced cement composites (HPFRCC)
blocks. Long embedment was investigated as well to gain insights on
the distribution of strain, slip, bar stress and bond stress along the bar
especially in post-yield range. A total of 12 specimens were tested,
by means of pull-out of the reinforcing bars from concrete blocks. It
was found that the enhancement of local bond strength can be
reached up to 50% and ductility of the bond behavior was improved
significantly if HPFRCC is used. Also, under a constant strain at
loaded end, HPFRCC has delayed yielding of bars at other location
from the loaded end. Hence, the reduction of bond stress was slower
for HPFRCC in comparison with NC. Due to the same reason, the
total slips at loaded end for HPFRCC was smaller than NC as
expected. Test results indicated that HPFRCC has better bond slip
behavior which makes it a suitable material to be employed in
anchorage zone such as beam-column joints.
Abstract: This article is to introduce the meaning and form of
social quality moving process as indicated by members of two suburb
communities with different social and cultural contexts. The form of
social quality moving process is very significant for the community
and social development, because it will make the people living
together with sustainable happiness.
This is a qualitative study involving 30 key-informants from two
suburb communities. Data were collected though key-informant
interviews, and analyzed using logical content description and
descriptive statistics.
This research found that on the social quality component, the
people in both communities stressed the procedure for social qualitymaking.
This includes the generousness, sharing and assisting among
people in the communities. These practices helped making people to
live together with sustainable happiness. Living as a family or appear
to be a family is the major social characteristic of these two
communities.
This research also found that form of social quality’s moving
process of both communities stress relation of human and nature;
“nature overpower humans” paradigm and influence of religious
doctrine that emphasizes relations among humans. Both criteria make
the form of social’s moving process simple, adaptive to nature and
caring for opinion sharing and understanding among each other
before action. This form of social quality’s moving process is
composed of 4 steps; (1) awareness building, (2) motivation to
change, (3) participation from every party which is concerned (4)
self-reliance.
Abstract: The fatigue life of tubular joints commonly found in
offshore industry is not only dependent on the value of hot-spot stress
(HSS), but is also significantly influenced by the through-thethickness
stress distribution characterized by the degree of bending
(DoB). The determination of DoB values in a tubular joint is essential
for improving the accuracy of fatigue life estimation using the stresslife
(S–N) method and particularly for predicting the fatigue crack
growth based on the fracture mechanics (FM) approach. In the
present paper, data extracted from finite element (FE) analyses of
tubular KT-joints, verified against experimental data and parametric
equations, was used to investigate the effects of geometrical
parameters on DoB values at the crown 0°, saddle, and crown 180°
positions along the weld toe of central brace in tubular KT-joints
subjected to axial loading. Parametric study was followed by a set of
nonlinear regression analyses to derive DoB parametric formulas for
the fatigue analysis of KT-joints under axial loads. The tubular KTjoint
is a quite common joint type found in steel offshore structures.
However, despite the crucial role of the DoB in evaluating the fatigue
performance of tubular joints, this paper is the first attempt to study
and formulate the DoB values in KT-joints.
Abstract: Auditory hallucinations among the most invalidating
and distressing experiences reported by patients diagnosed with
schizophrenia, leading to feelings of powerlessness and helplessness
towards their illness. In more severe cases, these auditory
hallucinations can take the form of commanding voices, which are
often related to high suicidality rates in these patients. Several
authors propose that the meanings attributed to the hallucinatory
experience, rather than characteristics like form and content, can be
determinant in patients’ reactions to hallucinatory activity,
particularly in the case of voice-hearing experiences. In this study, 48
patients diagnosed with paranoid schizophrenia presenting auditory
hallucinations were studied. Multiple regression analyses were
computed to study the influence of several developmental aspects,
such as family and social dynamics, bullying, depression, and sociocognitive
variables on the auditory hallucinations, on patients’
attributions and relationships with their voices, and on the resulting
invalidation of hallucinatory experience. Overall, results showed how
relationships with voices can mirror several aspects of interpersonal
relationship with others, and how self-schemas, depression and actual
social relationships help shaping the voice-hearing experience. Early
experiences of victimization and submission help predict the
attributions of omnipotence of the voices, and increased hostility
from parents seems to increase the malevolence of the voices,
suggesting that socio-cognitive factors can significantly contribute to
the etiology and maintenance of auditory hallucinations. The
understanding of the characteristics of auditory hallucinations and the
relationships patients established with their voices can allow the
development of more promising therapeutic interventions that can be
more effective in decreasing invalidation caused by this devastating
mental illness.
Abstract: On the basis of the theory of nonlinear elasticity, the
effect of homogeneous stress on the propagation of Lamb waves in
an initially isotropic hyperelastic plate is analysed. The equations
governing the propagation of small amplitude waves in the prestressed
plate are derived using the theory of small deformations
superimposed on large deformations. By enforcing traction free
boundary conditions at the upper and lower surfaces of the plate,
acoustoelastic dispersion equations for Lamb wave propagation are
obtained, which are solved numerically. Results are given for an
aluminum plate subjected to a range of applied stresses.
Abstract: This paper presents a numerical investigation of two
horizontally mounted four-lobed swirl pipes in terms of swirl
induction effectiveness into flows passing through them. The swirl
flows induced by the two swirl pipes have the potential to improve
the efficiency of Clean-In-Place procedures in a closed processing
system by local intensification of hydrodynamic impact on the
internal pipe surface. Pressure losses, swirl development within the
two swirl pipe, swirl induction effectiveness, swirl decay and wall
shear stress variation downstream of two swirl pipes are analyzed and
compared. It was found that a shorter length of swirl inducing pipe
used in joint with transition pipes is more effective in swirl induction
than when a longer one is used, in that it has a less constraint to the
induced swirl and results in slightly higher swirl intensity just
downstream of it with the expense of a smaller pressure loss. The
wall shear stress downstream of the shorter swirl pipe is also slightly
larger than that downstream of the longer swirl pipe due to the
slightly higher swirl intensity induced by the shorter swirl pipe. The
advantage of the shorter swirl pipe in terms of swirl induction is more
significant in flows with a larger Reynolds Number.
Abstract: Aim of this work is to determine the theoretical and
experimental properties of filament wound glass fiber/epoxy resin
composite pipes with different winding design subjected under
bending. For determination of bending strength of composite samples
three point bending tests were conducted. Good correlation between
theoretical and experimental results has been obtained, where sample
No4 has shown the highest value of bending strength. All samples
have demonstrated matrix cracking and fiber failure followed by
layers delamination during testing. Also, it was found that smaller
winding angles lead to an increase in bending stress. From presented
results good merger between glass fibers and epoxy resin was
confirmed by SEM analysis.
Abstract: Non-crimp 3D orthogonal fabric composite is one of
the textile-based composite materials that are rapidly developing
light-weight engineering materials. The present paper focuses on
geometric and micromechanical modeling of non-crimp 3D
orthogonal carbon fabric and composites reinforced with it for
aerospace applications. In this research meso-finite element (FE)
modeling employs for stress analysis in different load conditions.
Since mechanical testing of expensive textile carbon composites with
specific application isn't affordable, simulation composite in a virtual
environment is a helpful way to investigate its mechanical properties
in different conditions.
Abstract: The aim of the current study was to develop and
validate a Response to Stressful Situations Scale (RSSS) for the
Portuguese population. This scale assesses the degree of stress
experienced in scenarios that can constitute positive, negative and
more neutral stressors, and also describes the physiological,
emotional and behavioral reactions to those events according to their
intensity. These scenarios include typical stressor scenarios relevant
to patients with schizophrenia, which are currently absent from most
scales, assessing specific risks that these stressors may bring on
subjects, which may prove useful in non-clinical and clinical
populations (i.e. Patients with mood or anxiety disorders,
schizophrenia). Results from Principal Components Analysis and
Confirmatory Factor Analysis of two adult samples from general
population allowed to confirm a three-factor model with good fit
indices: χ2 (144)= 370.211, p = 0.000; GFI = 0.928; CFI = 0.927; TLI =
0.914, RMSEA = 0.055, P(rmsea ≤0.005) = .096; PCFI = .781.
Further data analysis of the scale revealed that RSSS is an adequate
assessment tool of stress response in adults to be used in further
research and clinical settings, with good psychometric characteristics,
adequate divergent and convergent validity, good temporal stability
and high internal consistency.
Abstract: To understand the friction stir welding process, it is
very important to know the nature of the material flow in and around
the tool. The process is a combination of both thermal as well as
mechanical work i.e. it is a coupled thermo-mechanical process.
Numerical simulations are very much essential in order to obtain a
complete knowledge of the process as well as the physics underlying
it. In the present work a model based approach is adopted in order to
study material flow. A thermo-mechanical based CFD model is
developed using a Finite Element package, Comsol Multiphysics.
The fluid flow analysis is done. The model simultaneously predicts
shear strain fields, shear strain rates and shear stress over the entire
workpiece for the given conditions. The flow fields generated by the
streamline plot give an idea of the material flow. The variation of
dynamic viscosity, velocity field and shear strain fields with various
welding parameters is studied. Finally the result obtained from the
above mentioned conditions is discussed elaborately and concluded.
Abstract: We propose new multiple-channel piezoelectric (PZT)
actuated tunable optical filter based on racetrack multi-ring
resonators for wavelength de-multiplexing network applications. We
design tunable eight-channel wavelength de-multiplexer consisting of
eight cascaded PZT actuated tunable multi-ring resonator filter with a
channel spacing of 1.6nm. The filter for each channel is basically
structured on a suspended beam, sandwiched with piezoelectric
material and built in integrated ring resonators which are placed on
the middle of the beam to gain uniform stress and linearly varying
longitudinal strain. A reference single mode serially coupled multi
stage racetrack ring resonator with the same radii and coupling length
is designed with a line width of 0.8974nm with a flat top pass band at
1dB of 0.5205nm and free spectral range of about 14.9nm. In each
channel, a small change in the perimeter of the rings is introduced to
establish the shift in resonance wavelength as per the defined channel
spacing. As a result, when a DC voltage is applied, the beams will
elongate, which involves mechanical deformation of the ring
resonators that induces a stress and a strain, which brings a change in
refractive index and perimeter of the rings leading to change in the
output spectrum shift providing the tunability of central wavelength
in each channel. Simultaneous wave length shift as high as
45.54pm/
Abstract: All current experimental methods for determination of
stress intensity factors are based on the assumption that the state of
stress near the crack tip is plane stress. Therefore, these methods rely
on strain and displacement measurements made outside the near
crack tip region affected by the three-dimensional effects or by
process zone. In this paper, we develop and validate an experimental
procedure for the evaluation of stress intensity factors from the
measurements of the out-of-plane displacements in the surface area
controlled by 3D effects. The evaluation of stress intensity factors is
possible when the process zone is sufficiently small, and the
displacement field generated by the 3D effects is fully encapsulated
by K-dominance region.
Abstract: The grain quality of chickpea in Iran is low and
instable, which may be attributed to the evolution of cultivars with a
narrow genetic base making them vulnerable to biotic stresses. Four
chickpea varieties from diverse geographic origins were chosen and
arranged in a randomized complete block design. Mesorhizobium sp.
cicer strain SW7 was added to all the chickpea seeds. Chickpea seeds
were planted on October 9, 2013. Each genotype was sown 5 m in
length, with 35 cm inter-row spacing, in 3 rows. Weeds were
removed manually in all plots. Results showed that Analysis of
variance on the studied traits showed significant differences among
genotypes for N, P, K and Fe contents of chickpea, but there is not a
significant difference among Ca, Zn and Mg continents of chickpea.
The experimental coefficient of variation (CV) varied from 7.3 to
15.8. In general, the CV value lower than 20% is considered to be
good, indicating the accuracy of conducted experiments. The highest
grain N was observed in Hashem and Jam cultivars. The highest grain
P was observed in Jam cultivar. Phosphorus content (mg/100g)
ranged from 142.3 to 302.3 with a mean value of 221.3. The negative
correlation (-0.126) was observed between the N and P of chickpea
cultivars. The highest K and Fe contents were observed in Jam
cultivar.
Abstract: The potential neuroprotective effect of Phyllantus
nuriri against Fe2+ and sodium nitroprusside (SNP) induced oxidative
stress in mitochondria of rats brain was evaluated. Cellular viability
was assessed by MTT reduction, reactive oxygen species (ROS)
generation was measured using the probe 2,7-dichlorofluoresce
indiacetate (DCFH-DA). Glutathione content was measured using
dithionitrobenzoic acid (DTNB). Fe2+ (10μM) and SNP (5μM)
significantly decreased mitochondrial activity, assessed by MTT
reduction assay, in a dose-dependent manner, this occurred in parallel
with increased glutathione oxidation, ROS production and lipid
peroxidation end-products (thiobarbituric acid reactive substances,
TBARS). The co-incubation with methanolic extract of Phyllantus
nuriri (10-200 μg/ml) reduced the disruption of mitochondrial
activity, gluthathione oxidation, ROS production as well as the
increase in TBARS levels caused by both Fe2+ and SNP in a dose
dependent manner. HPLC analysis of the extract revealed the
presence of gallic acid (20.540.01), caffeic acid (7.930.02), rutin
(25.310.05), quercetin (31.280.03) and kaemferol (14.360.01).
This result suggests that these phytochemicals account for the
protective actions of P. niruri against Fe2+ and SNP -induced
oxidative stress. Our results show that P. nuriri consist important
bioactive molecules in the search for an improved therapy against the
deleterious effects of Fe2+, an intrinsic producer of reactive oxygen
species (ROS), that leads to neuronal oxidative stress and
neurodegeneration.
Abstract: In this paper, an analytical simplified method for
calculating elasto-plastic stresses strains of notched bodies subject to
non-proportional loading paths is discussed. The method was based
on the Neuber notch correction, which relates the incremental elastic
and elastic-plastic strain energy densities at the notch root and the
material constitutive relationship. The validity of the method was
presented by comparing computed results of the proposed model
against finite element numerical data of notched shaft. The
comparison showed that the model estimated notch-root elasto-plastic
stresses strains with good accuracy using linear-elastic stresses. The
prosed model provides more efficient and simple analysis method
preferable to expensive experimental component tests and more
complex and time consuming incremental non-linear FE analysis.
The model is particularly suitable to perform fatigue life and fatigue
damage estimates of notched components subjected to nonproportional
loading paths.