Real-time 3D Echocardiography (RT3DE) has been proven to be an accurate tool for left ventricular (LV) volume assessment. However, identification of the LV endocardium remains a challenging task, ...mainly because of the low tissue/blood contrast of the images combined with typical artifacts. Several semi and fully automatic algorithms have been proposed for segmenting the endocardium in RT3DE data in order to extract relevant clinical indices, but a systematic and fair comparison between such methods has so far been impossible due to the lack of a publicly available common database. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms developed to segment the LV border in RT3DE. A database consisting of 45 multivendor cardiac ultrasound recordings acquired at different centers with corresponding reference measurements from three experts are made available. The algorithms from nine research groups were quantitatively evaluated and compared using the proposed online platform. The results showed that the best methods produce promising results with respect to the experts' measurements for the extraction of clinical indices, and that they offer good segmentation precision in terms of mean distance error in the context of the experts' variability range. The platform remains open for new submissions.
Let
R
be a commutative Noetherian ring and
I
a proper ideal of
R
. In this paper, we study finitely generated
R
-modules
M
with only one non-vanishing local cohomology module
H
I
c
(
M
)
where
c
=
c
...d
(
I
,
M
)
. Let
C
be a semidualizing
R
-module. We investigate the conditions under which
H
I
c
(
M
)
belongs to either the Auslander class
A
C
(
R
)
or the Bass class
B
C
(
R
)
.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
The present study aimed to calculate the yields of DNA
breaks and the variation of relative biological effectiveness (RBE)
at different depths for protons using Geant4-DNA. For this purpose,
...an atomic model of DNA and a DNA damage classification matrix were
used to calculate different DNA break yields for 62-MeV protons. As
the reference radiation, the secondary electron spectrum produced by
60
Co was evaluated. This helped to calculate the SSB and DSB
yields. Moreover, RBE was found to be between 1.1 at the first point
and 1.51 in the Bragg peak region. In this region, it was 37%
greater than the 5-mm depth in the plateau region. Considering
different threshold energies, the energy deposition at 10.79 eV had
the most contribution to the total damage. As the results suggested,
the depth dependence of RBE should be taken into account for proton
therapy. It was also found that DNA break yields significantly
depend on the threshold energy value.
Electronic sensitivity of pristine, Al- and Si-doped BC3 nanosheets to formaldehyde (H2CO) molecule was investigated by utilizing density functional theory. It was found that H2CO is weakly adsorbed ...on the sheet, releasing energy of 11.35kcal/mol, and electronic properties of the sheet are not significantly changed. Although both Al and Si dopings make the sheet more reactive and sensitive to H2CO, Si doping seems to be a better strategy to manufacture H2CO chemical sensors due to the shorter recovery time and higher sensitivity of the Si-doped sheet. Our calculations show that the HOMO/LUMO gap of the Si-doped sheet is significantly decreased from 2.20 to 1.58eV upon H2CO adsorption, which may increase the electrical conductance of the sheet. Therefore, the doped sheet might convert the presence of H2CO molecules to electrical signal. Moreover, the shorter recovery time of the Si-doped sheet is due to middle adsorption energy of −26.49kcal/mol in comparison with −40.50kcal/mol for the Al-doped sheet.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•We design and manufacture an ultrasonic assisted tensile test system.•Five specimens of Al 1098 with different grain sizes are prepared by ECAP process.•We investigate the effect of grain size on ...acoustic softening.•Larger grain sizes show more flow stress reduction while applying ultrasonic vibrations.•Acoustic softening may be due to increasing dislocation mobility as well as dislocation annihilation.
The objective of this paper is to reveal the main cause of volume effects of ultrasonic vibrations on the plastic behavior of pure aluminum specimens. For this purpose, specimens with different grain sizes were made by ECAP. An experimental tensile test system was designed and made, in which the specimens could be excited by ultrasonic vibrations with a frequency of 20kHz and amplitude of 5μm. Five specimens with grain sizes of 109, 38, 15, 7 and 0.97μm were prepared. Tensile tests of the specimens were performed at room temperature and at constant speed of 0.2mm/min under static load and superimposed ultrasonic excitations. It was found that ultrasonic vibrations had a remarkable influence on the plastic behavior of pure aluminum and after applying ultrasonic vibrations, flow stress of the all specimens reduced. Reduction of flow stress was dependent on grain size. The specimens with the largest grain size of 109μm showed a flow stress reduction of 66% while finest grain size of 0.97μm, a reduction of 11.3% was observed. The result of the current study can help to understand the underlying mechanisms of ultrasonic softening.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Micro-news on social media are short summaries of news content.•Survey of U.S. adults on micro-news consumption patterns.•Identified six motivations for reading micro-news on mobile.•Habits ...significantly explain continuance intention beyond motivation.•Context stability of time and situation is correlated with habit.
Micro-news are abbreviated summaries or teasers of news content that are often accompanied with links to longer articles. We investigated motivations and habits of micro-news consumption through mobile social media platforms and how these variables relate to continuation intention. We surveyed 250 U.S. adults and identified six motivations using a uses and gratifications approach: social utility, pass time, entertainment, local information-seeking, salient information-seeking, and financial information-seeking. We found that habits add significant explanatory power on top of motivation in explaining users’ continuance intention. Context stability of time and situation, but not location, was correlated with habit.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
We represent small
Z
- and
Y
-gradient coils with higher gradient strength and slew rate for mouse MRI. The coil geometries are optimized based on predetermined conditions for the gradient ...strength and slew rate in terms of minimum power consumption and acceptable linearity for the variation of the magnetic fields using the particle swarm optimization algorithm in computer simulation technology. The simulation results verify that the magnitudes of the field strength and slew rate have reached up to
144
m
T
⋅
m
−
1
and
1297
m
T
⋅
(
m
⋅
m
s
)
−
1
for the
Z
-gradient coil and increased to
109
m
T
⋅
m
−
1
and
1264
m
T
⋅
(
m
⋅
m
s
)
−
1
for the
Y
-gradient coil, respectively. Furthermore, the optimal geometry of the
Z
-gradient coil derived from a simulation study was then fabricated, and its parameters were measured using a Hall sensor. The gradient strength and slew rate of the fabricated
Z
-gradient coil were measured at
131
m
T
⋅
m
−
1
and
1180
m
T
⋅
(
m
⋅
m
s
)
−
1
, respectively, which have only a 9% difference from the corresponding simulated parameters.
The formation of Al4C3 interphase in carbon nanotube (CNT)-reinforced aluminum (Al) nanocomposites is a critical issue which must be well-known to more realistic estimations of mechanical behavior of ...such materials. In this work, the effect of Al4C3 interphase on the elastic modulus of Al nanocomposites reinforced with randomly distributed CNTs is investigated using a numerical micromechanical model based on the finite element method (FEM). Moreover, the influences of the CNT volume fraction and diameter on the elastic modulus of Al nanocomposites are explored. The results reveal that Al4C3 interphase significantly affects the elastic modulus of Al nanocomposites especially as the CNT diameter decreases. It can be observed that with increasing interphase thickness, the elastic modulus of the nanocomposite increases. The applicability of the presented model in predicting the elastic modulus of CNT-reinforced Al nanocomposites is investigated by comparing the results of the FEM with those of experiment available in the literature. Furthermore, the results of the FEM with and without Al4C3 interphase for aligned continuous and discontinuous CNT-reinforced Al nanocomposites are presented. It is found that the effect of the interphase on the elastic modulus of nanocomposites reinforced with continuous CNT is more important than that of nanocomposites reinforced with discontinuous CNT.
•Elastic modulus of random microstructure CNT/Al nanocomposites is predicted.•Effect of Al4C3 interphase on the elastic modulus is investigated.•The influences of CNT volume fraction and diameter are examined.•Al4C3 interphase strongly affects the elastic modulus of nanocomposite.•Decreasing the CNT diameter leads to increasing the elastic modulus.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Evaluated previous two-phase flow frictional pressure drop correlations.•Proposed a new correlation for condensation frictional pressure drop in mini/micro and macro channels.•Verified the model ...with 7328 data points from 35 published papers.•Discussed the effects of the input parameters on the frictional pressure drop.
A general nonlinear equation for estimating the frictional pressure drop during condensation of fluids in different mini/micro and macro channels was obtained using the genetic programming (GP). The developed model is similar to that of the Lockhart and Martinelli 1 model. For developing the new correlation, 7328 data points were collected from 35 sources, which cover a wide range of fluids, channel geometries, diameters, mass fluxes, and saturation temperatures for single-port and multi-port channels. The newly developed correlation for the two-phase flow predicted a wide range of conditions with an average absolute relative deviation (AARD) of 22.92%. The same database was used for the evaluation of the available empirical correlations. Their deviations were significantly higher than that of the new correlation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Excess pore water pressure (EPWP) measurements taken at different positions on a penetrating piezocone into a clayey soil are believed to play an important role in correlating to its ...characteristics. On this subject, many correlations were proposed by several researchers, mainly empirically and mostly with EPWPs measured at the cone shoulder (u2). The use of EPWP measurements at other positions, for example, behind the friction sleeve (u3) has not been evaluated, possibly because of the lack of u3 measuring elements for most penetrometers on the market. In this study, the piezocone penetration test in saturated intact clays was numerically modeled using finite element formulation. The EPWP distribution generated along the friction sleeve was investigated and it was found that the previously mentioned distribution closely followed an exponential trend which was mainly affected by the overconsolidation ratio (OCR) and the rigidity index (Ir) of the soil. Further investigations led this study to propose an innovative relationship to estimate u3 values from measurements of common piezocone tests on the market (u2-type) and pertinent soil characteristics. The well-predicting capability of numerical modeling procedures and the proposed relationship was compared with and validated with available experimental and field piezocone test measurements.
