591 research outputs found
Sorption of Eu(III) on Attapulgite Studied by Batch, XPS and EXAFS Techniques.
The effects of pH, ionic strength and temperature on sorption of Eu(III) on attapulgite were investigated in the presence and absence of fulvic acid (FA) and humic acid (HA). The results indicated that the sorption of Eu(III) on attapulgite was strongly dependent on pH and ionic strength, and independent of temperature. In the presence of FA/HA, Eu(III) sorption was enhanced at pH 7. The X-ray photoelectron spectroscopy (XPS) analysis suggested that the sorption of Eu(III) might be expressed as ≡X3Eu0 ≡SwOHEu3+ and ≡SOEu-OOC-/HA in the ternary Eu/HA/attapulgite system. The extended X-ray absorption fine structure (EXAFS) analysis of Eu-HA complexes indicated that the distances of d(Eu-O) decreased from 2.451 to 2.360 Å with increasing pH from 1.76 to 9.50, whereas the coordination number (N) decreased from ~9.94 to ~8.56. Different complexation species were also found for the different addition sequences of HA and Eu(III) to attapulgite suspension. The results are important to understand the influence of humic substances on Eu(III) behavior in the natural environment
Experimental Investigation on the Tensile Strength of Composite Laminates Containing Open and Filled Holes
An experimental study is performed to evaluate
the effects of clamping pressure, friction, and
washer size on the static performance of composite
laminates with open and bolt-filled holes.
The static tensile strength and failure behavior
of composite laminates with an open hole and a
bolt-filled hole are analyzed and compared. Experimental
results show that the static tensile
strength of composite laminates is sensitive to
pre-existing damage of both open- or filled-hole
laminates. In contrast, a comparison between
the experimental results of open- and filled-hole
specimens proved that whether the hole is open
or filled has a feeble influence on the tensile-tensile
fatigue strength of studied composite laminates.
In comparison, however, it is found that
the inserted washer size, bolt clamping force,
and friction force strongly affect the tensile
strength of open- and filled-hole composite laminates.
Moreover, application of thicker washers
and hi-lock bolt will significantly increase
the static strength and fatigue life of composite
laminates with a bolt-filled hole.Экспериментально оценено влияние силы зажима, трения и размера шайбы на статические
характеристики слоистых композитов со сквозными и болтовыми отверстиями. Проведено
сравнение статического предела прочности при растяжении и характера разрушения слоистых композитов со сквозным и болтовым отверстиями. Результаты экспериментальных
исследований показали, что на статический предел прочности при растяжении слоистых
композитов влияет изначальное повреждение независимо от наличия сквозного или болтового
отверстия. Сравнительный анализ результатов исследований образцов со сквозным и болтовым отверстиями подтвердил тот факт, что вид отверстия (сквозное или болтовое)
незначительно влияет на усталостную прочность при растяжении исследуемых слоистых
композитов. Установлено, что такие факторы, как размер шайбы, сила зажима болта и
сила трения, существенно влияют на предел прочности при растяжении слоистых композитов со сквозным или болтовым отверстием. Использование утолщенных шайб между
слоистым материалом и болтом-заклепкой значительно увеличивает статическую прочность и долговечность слоистых композитов с болтовыми отверстиями.Експериментально досліджено вплив сили затиску, тертя і розміру шайби на статичні
характеристики шаруватих композитів із наскрізними і болтовими отворами. Проведено порівняння статичної границі міцності при розтязі і характера руйнування
шаруватих композитів із наскрізними і болтовими отворами. Результати експериментальних досліджень показали, що на статичну границю міцності при розтязі
шаруватих композитів впливає початкове пошкодження незалежно від наявності
наскрізного чи болтового отвору. Порівняльний аналіз результатів досліджень зразків із наскрізними і болтовими отворами підтвердив той факт, що вид отвору
(наскрізне чи болтове) незначно впливає на міцність від утомленості при розтязі
досліджуваних шаруватих композитів. Установлено, що такі чинники, як розмір
шайби, сила затиску болта і сила тертя, суттєво впливають на границю міцності при
розтязі шаруватих композитів із наскрізним чи болтовим отвором. Використання
стовщених шайб між шаруватим матеріалом і болтом-заклепкою значно збільшує
статичну міцність і довговічність шаруватих композитів із болтовими отворам
Research of Curve Fitting Method on the Measured Settlement of Tanks
AbstractThe settlement data of oil storage tanks made of steel are measured by the measurement points located around the base of the tank wall. The measured settlement data need to be curve fitted in order to reflect the settlement distribution around the whole tank wall base. Considering about the disadvantage of measured settlement data treatment methods on tanks in current standards, an optimization method of curve fitting on the measured settlement data is presented. The Fourier series expansion is used to analyze the measured settlement data, the fitting curves and mean square error according to different order are obtained. The fitting curve with minimum mean square error is selected as the most appropriate one that reflects the actual displacement of the tank base. The optimization method of curve fitting present is applied to analyze the measured settlement data obtained from the floating roof tank and the fixed roof tank. Results show that different effects can be obtained with different order of the fitting curve. Curve fitting referring to different order is necessary to the measured settlement data in actual engineering in order to find the most appropriate one that reflects the real tank base displacement distribution
Enhancing gravitational wave astronomy with galaxy catalogues
Joint gravitational wave (GW) and electromagnetic (EM) observations, as a key
research direction in multi-messenger astronomy, will provide deep insight into
the astrophysics of a vast range of astronomical phenomena. Uncertainties in
the source sky location estimate from gravitational wave observations mean
follow-up observatories must scan large portions of the sky for a potential
companion signal. A general frame of joint GW-EM observations is presented by a
multi-messenger observational triangle. Using a Bayesian approach to
multi-messenger astronomy, we investigate the use of galaxy catalogue and host
galaxy information to reduce the sky region over which follow-up observatories
must scan, as well as study its use for improving the inclination angle
estimates for coalescing binary compact objects. We demonstrate our method
using a simulated neutron stars inspiral signal injected into simulated
Advanced detectors noise and estimate the injected signal sky location and
inclination angle using the Gravitational Wave Galaxy Catalogue. In this case
study, the top three candidates in rank have , and posterior
probability of being the host galaxy, receptively. The standard deviation of
cosine inclination angle (0.001) of the neutron stars binary using
gravitational wave-galaxy information is much smaller than that (0.02) using
only gravitational wave posterior samples.Comment: Proceedings of the Sant Cugat Forum on Astrophysics. 2014 Session on
'Gravitational Wave Astrophysics
A pair of positive solutions for the Dirichlet p(z)-Laplacian with concave and convex nonlinearities
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