2,091 research outputs found
Drying process in the formation of sol-gel-derived TiO2 ceramic membrane
Accurate drying data for thin titania gel layers dried at 40°C and 20% relative humidity (RH) are given. The drying rate versus free moisture content diagram should show three regions as predicted by the classical drying theory. They are the constant rate period, the first falling rate period and the second falling rate period. The second falling rate period was not observed in the present case, because at 40°C and 20% RH the equilibrium moisture content will be enough to provide a continuous fluid network in the gel. The total drying time in the falling rate period increases with layer thickness. The drying mechanism in the first falling rate period was identified as capillary flow
Targeting of anionic membrane species by lanthanide(III) complexes: towards improved MRI contrast agents for apoptosis
No abstract available
Stabilization of the porous texture of nanostructured titanic by avoiding a phase transformation
Intrinsic quadrupole moment of the nucleon
We address the question of the intrinsic quadrupole moment Q_0 of the nucleon
in various models. All models give a positive intrinsic quadrupole moment for
the proton. This corresponds to a prolate deformation. We also calculate the
intrinsic quadrupole moment of the Delta(1232). All our models lead to a
negative intrinsic quadrupole moment of the Delta corresponding to an oblate
deformation.Comment: 17 pages, 5 figure
Railway track degradation modelling using dynamic multi-regression to predict failure patterns
Railway tracks degrade and may eventually break down due to several operational and environmental impacts that affect the rails’ reliability. The most common type of railhead defect is called the rail squat, which cost Network Rail an estimate of approximately 3.9 million pounds annually. Squat defects are minor subsurface laminations that run diagonally down the running surface and spread laterally and longitudinally over and along the rail tracks (Li, Zili et al., 2008a; Li, Zili et al., 2008b; Li, Z., 2009). The occurrence of squat defects has a significant impact on the track performance, leading to speed restrictions, delays, and cancellation of in-service train operations and hence penalties for infrastructure owners. To ensure the performance and efficiency of service operations and more reliable railway infrastructure, the UK is investing in railway modernization projects to meet this demand (Rail director April 2023, 2023; MyBib Contributors, 2019).This study uses a Dynamic Multiple linear regression to model the relationship between squat defects and influential parameters such as track length, maximum permissible speed, maximum axle load, estimated million gross tonnage, tamping frequency, rail grinding frequency, and corrugation frequency detection. A hazard model is proposed and used to predict transition probabilities between defect and failure. This research evaluated six years of data acquired from network rail on squats defects, grinding maintenance, and corrugation faults across the UK railway network. The dynamic Markov model is used within the scope of the hazard model to determine the transition probabilities of squat defects propagation. A complete squat data analysis is performed by comparing the efficiency of the rail gridding maintenance regime to the cumulative squat defect frequency against the number of repair operations. An example simulation is shown to anticipate the time to breakdown of railway track systems
Scale invariance in coarsening of binary and ternary fluids
Phase separation in binary and ternary fluids is studied using a two
dimensional Lattice Gas Automata. The lengths, given by the the first zero
crossing point of the correlation function and the total interface length is
shown to exhibit power law dependence on time. In binary mixtures, our data
clearly indicate the existence of a regime having more than one length scale
where the coarsening process proceeds through the rupture and reassociation of
domains. In ternary fluids; in the case of symmetric mixtures there exists a
regime with a single length scale having dynamic exponent 1/2, while in
asymmetric mixtures our data establish the break down of scale invariance.Comment: 20 pages, 13 figure
Executive Summary: Understanding the lives of adolescents and young adults (UDAYA) in Uttar Pradesh, India (2015–16)
A program of research titled, “Understanding the lives of adolescents and young adults (UDAYA) in Bihar and Uttar Pradesh,” implemented by the Population Council, aimed to understand the factors that determine healthy transitions from childhood to adolescence and adulthood. The goal of UDAYA is to establish the levels, patterns, and trends in the situation of younger (10–14) and older (15–19) adolescents and assess factors that influence the quality of transitions they make. The specific objectives of UDAYA are: 1) to explore the situation of adolescents, with a focus on assessing the extent to which both younger and older adolescents have acquired a set of assets that can help them make a healthy, safe, and successful transition from adolescence to young adulthood in the states of Bihar and Uttar Pradesh; 2) to describe the extent to which the situation of adolescents has changed over time; and 3) to assess factors that determine the accumulation or loss of assets and the quality of transitions from adolescence to young adulthood. This report presents findings from Uttar Pradesh
Close encounters of a rotating star with planets in parabolic orbits of varying inclination and the formation of Hot Jupiters
(abbreviated) We extend the theory of close encounters of a planet on a
parabolic orbit with a star to include the effects of tides induced on the
central rotating star. Orbits with arbitrary inclination to the stellar
rotation axis are considered. We obtain results both from an analytic treatment
and numerical one that are in satisfactory agreement. These results are applied
to the initial phase of the tidal circularisation problem. We find that both
tides induced in the star and planet can lead to a significant decrease of the
orbital semi-major axis for orbits having periastron distances smaller than 5-6
stellar radii (corresponding to periods days after the
circularisation has been completed) with tides in the star being much stronger
for retrograde orbits compared to prograde orbits. We use the simple Skumanich
law for the stellar rotation with its rotational period equal to one month at
the age of 5Gyr. The strength of tidal interactions is characterised by
circularisation time scale, defined as a time scale of evolution of
the planet's semi-major axis due to tides considered as a function of orbital
period after the process of tidal circularisation has been completed.
We find that the ratio of the initial circularisation time scales corresponding
to prograde and retrograde orbits is of order 1.5-2 for a planet of one Jupiter
mass and four days. It grows with the mass of the planet, being
of order five for a five Jupiter mass planet with the same . Thus, the
effect of stellar rotation may provide a bias in the formation of planetary
systems having planets on close orbits around their host stars, as a
consequence of planet-planet scattering, favouring systems with retrograde
orbits. The results may also be applied to the problem of tidal capture of
stars in young stellar clusters.Comment: to be published in Celestial Mechanics and Dynamical Astronom
Understanding the lives of adolescents and young adults (UDAYA) in Uttar Pradesh, India (2015–16)
The goal of the program of research titled “Understanding the lives of adolescents and young adults (UDAYA) in Bihar and Uttar Pradesh” is to establish the levels, patterns, and trends in the situation of younger (10–14) and older (15–19) adolescents and to assess factors that influence the quality of transitions they make. The study is designed to provide robust insights on how investments in adolescents influence their life course by the time they reach young adulthood; enable evidence-based decisions on the types of programs worthy of scale-up; and furnish important baseline indicators against which the long-term impact of programs can be measured. This report focuses on the findings from the first round of cross-sectional surveys of adolescents conducted in Uttar Pradesh, which confirm that adolescents are a heterogeneous group with correspondingly diverse needs. The findings of UDAYA show that adolescents face numerous challenges in making the transition to adulthood. The report identifies and discusses several programmatic areas for action to improve the situation of adolescents
Scaling and Crossover in the Large-N Model for Growth Kinetics
The dependence of the scaling properties of the structure factor on space
dimensionality, range of interaction, initial and final conditions, presence or
absence of a conservation law is analysed in the framework of the large-N model
for growth kinetics. The variety of asymptotic behaviours is quite rich,
including standard scaling, multiscaling and a mixture of the two. The
different scaling properties obtained as the parameters are varied are
controlled by a structure of fixed points with their domains of attraction.
Crossovers arising from the competition between distinct fixed points are
explicitely obtained. Temperature fluctuations below the critical temperature
are not found to be irrelevant when the order parameter is conserved. The model
is solved by integration of the equation of motion for the structure factor and
by a renormalization group approach.Comment: 48 pages with 6 figures available upon request, plain LaTe
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