6,898 research outputs found
Rehabilitation planning for small tanks in cascades: a methodology based on rapid assessment
Irrigation systems / Rehabilitation / Tank irrigation / Small-scale systems / Reservoirs / Conflict / Farmer participation / River Basin development / Water resources development / Arid zones / Sri Lanka
Reflection high-energy electron diffraction experimental analysis of polycrystalline MgO films with grain size and orientation distributions
Analysis of biaxial texture of MgO films grown by ion-beam-assisted deposition (IBAD) has been performed using a quantitative reflection high-energy electron diffraction (RHEED) based method. MgO biaxial texture is determined by analysis of diffraction spot shapes from single RHEED images, and by measuring the width of RHEED in-plane rocking curves for MgO films grown on amorphous Si3N4 by IBAD using 750 eV Ar+ ions, at 45° incidence angle, and MgO e-beam evaporation. RHEED-based biaxial texture measurement accuracy is verified by comparison with in-plane and out-of-plane orientation distribution measurements made using transmission electron microscopy and x-ray rocking curves. In situ RHEED measurements also enable the analysis of the evolution of the biaxial texture which narrows with increasing film thickness. RHEED-based measurements of IBAD MgO biaxial texture show that the minimum in-plane orientation distribution depends on the out-of-plane orientation distribution, and indicates that the minimum obtainable in-plane orientation on distribution is 2°
UniquID: A Quest to Reconcile Identity Access Management and the Internet of Things
The Internet of Things (IoT) has caused a revolutionary paradigm shift in
computer networking. After decades of human-centered routines, where devices
were merely tools that enabled human beings to authenticate themselves and
perform activities, we are now dealing with a device-centered paradigm: the
devices themselves are actors, not just tools for people. Conventional identity
access management (IAM) frameworks were not designed to handle the challenges
of IoT. Trying to use traditional IAM systems to reconcile heterogeneous
devices and complex federations of online services (e.g., IoT sensors and cloud
computing solutions) adds a cumbersome architectural layer that can become hard
to maintain and act as a single point of failure. In this paper, we propose
UniquID, a blockchain-based solution that overcomes the need for centralized
IAM architectures while providing scalability and robustness. We also present
the experimental results of a proof-of-concept UniquID enrolment network, and
we discuss two different use-cases that show the considerable value of a
blockchain-based IAM.Comment: 15 pages, 10 figure
Kinetics and mechanism of proton transport across membrane nanopores
We use computer simulations to study the kinetics and mechanism of proton
passage through a narrow-pore carbon-nanotube membrane separating reservoirs of
liquid water. Free energy and rate constant calculations show that protons move
across the membrane diffusively in single-file chains of hydrogen-bonded water
molecules. Proton passage through the membrane is opposed by a high barrier
along the effective potential, reflecting the large electrostatic penalty for
desolvation and reminiscent of charge exclusion in biological water channels.
At neutral pH, we estimate a translocation rate of about 1 proton per hour and
tube.Comment: 4 pages, 4 figure
Fe I Oscillator Strengths for the Gaia-ESO Survey
The Gaia-ESO Public Spectroscopic Survey (GES) is conducting a large-scale
study of multi-element chemical abundances of some 100 000 stars in the Milky
Way with the ultimate aim of quantifying the formation history and evolution of
young, mature and ancient Galactic populations. However, in preparing for the
analysis of GES spectra, it has been noted that atomic oscillator strengths of
important Fe I lines required to correctly model stellar line intensities are
missing from the atomic database. Here, we present new experimental oscillator
strengths derived from branching fractions and level lifetimes, for 142
transitions of Fe I between 3526 {\AA} and 10864 {\AA}, of which at least 38
are urgently needed by GES. We also assess the impact of these new data on
solar spectral synthesis and demonstrate that for 36 lines that appear
unblended in the Sun, Fe abundance measurements yield a small line-by-line
scatter (0.08 dex) with a mean abundance of 7.44 dex in good agreement with
recent publications.Comment: Accepted for publication in Mon. Not. R. Astron. So
Data sharing: not as simple as it seems
In recent years there has been a major change on the part of funders, particularly in North America, so that data sharing is now considered to be the norm rather than the exception. We believe that data sharing is a good idea. However, we also believe that it is inappropriate to prescribe exactly when or how researchers should preserve and share data, since these issues are highly specific to each study, the nature of the data collected, who is requesting it, and what they intend to do with it. The level of ethical concern will vary according to the nature of the information, and the way in which it is collected - analyses of anonymised hospital admission records may carry a quite different ethical burden than analyses of potentially identifiable health information collected directly from the study participants. It is striking that most discussions about data sharing focus almost exclusively on issues of ownership (by the researchers or the funders) and efficiency (on the part of the funders). There is usually little discussion of the ethical issues involved in data sharing, and its implications for the study participants. Obtaining prior informed consent from the participants does not solve this problem, unless the informed consent process makes it completely clear what is being proposed, in which case most study participants would not agree. Thus, the undoubted benefits of data sharing does not remove the obligations and responsibilities that the original investigators hold for the people they invited to participate in the study
Family memories in the home: contrasting physical and digital mementos
We carried out fieldwork to characterise and compare physical and digital mementos in the home. Physical mementos are highly valued, heterogeneous and support different types of recollection. Contrary to expectations, we found physical mementos are not purely representational, and can involve appropriating common objects and more idiosyncratic forms. In contrast, digital mementos were initially perceived as less valuable, although participants later reconsidered this. Digital mementos were somewhat limited in function and expression, largely involving representational photos and videos, and infrequently accessed. We explain these digital limitations and conclude with design guidelines for digital mementos, including better techniques for accessing and integrating these into everyday life, allowing them to acquire the symbolic associations and lasting value that characterise their physical counterparts
Virtual light-by-light scattering and the g factor of a bound electron
The contribution of the light-by-light diagram to the g factor of electron
and muon bound in Coulomb field is obtained. For electron in a ground state,
our results are in good agreement with the results of other authors obtained
numerically for large Z. For relatively small Z our results have essentially
higher accuracy as compared to the previous ones. For muonic atoms, the
contribution is obtained for the first time with the high accuracy in whole
region of Z.Comment: 10 pages, 3 figures, RevTe
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