850 research outputs found
History and development of non-intrusive electrical testing and assessment of DC traction motor armature condition and reliability during overhaul
The test regime has proven highly successful for QR over the past five years, being initially driven from the commercial view point of preventing costly operational failures of traction machines. The benefits of this policy are now starting to be realised, however, it has been a long process. Such developments are highly dependent on a detailed knowledge of the motor insulation and coil structure. This process of developing nonintrusive test indicators of traction machines is now also being applied to the stator windings of the newer three-phase asynchronous traction machines now starting service in QR. This basis for cost effective maintenance and minimisation of operational failures within QR continues. There is ongoing research into the development of these indicators, and the training QR staff and contractors in testing for these indicators, and observing unusual machine behaviour and deviation from normal operation
Greater belief in science predicts mask-wearing behavior during COVID-19
Coronavirus disease (COVID-19) pandemic impacted both the physical and psychological aspects of people\u27s lives. Personality traits are one of the factors that explain the diverse responses to stressful situations. This study aimed to investigate whether five-factor and maladaptive personality traits are associated with depressive and anxiety symptoms, suicide risk, self-reported COVID-19 symptoms, and preventive behaviors during the COVID-19 pandemic, comprehensively
Stiffness and strength of metal bridge deck forms
Light gauge metal sheeting is often utilized in the building and bridge industries for concrete formwork. Although the in-plane stiffness and strength of the metal forms are commonly relied upon for stability bracing in buildings, the forms are generally not considered for bracing in steel bridge construction. The primary difference between the forming systems in the two industries is the method of connection between the forms and girders. In bridge construction, an eccentric support angle is incorporated into the connection details to achieve a uniform slab thickness along the girder length. While the eccentric connection is a benefit for slab construction, the flexible connection limits the amount of bracing provided by the forms. This paper presents results from the first phase of a research study investigating the bracing behavior of metal bridge deck forms. Shear diaphragm tests were conducted to determine the shear stiffness and strength of bridge deck forms, and modified connection details were developed that substantially improve the bracing behavior of the forms. The measured stiffness and strength of diaphragms with the modified connection often met or exceeded the values of diaphragms with conventional noneccentric connections. The experimental results for the diaphragms with the modified connection details dramatically improve the potential for bracing of steel bridge girders by metal deck forms
Absolute Maximal Entanglement and Quantum Secret Sharing
We study the existence of absolutely maximally entangled (AME) states in
quantum mechanics and its applications to quantum information. AME states are
characterized by being maximally entangled for all bipartitions of the system
and exhibit genuine multipartite entanglement. With such states, we present a
novel parallel teleportation protocol which teleports multiple quantum states
between groups of senders and receivers. The notable features of this protocol
are that (i) the partition into senders and receivers can be chosen after the
state has been distributed, and (ii) one group has to perform joint quantum
operations while the parties of the other group only have to act locally on
their system. We also prove the equivalence between pure state quantum secret
sharing schemes and AME states with an even number of parties. This equivalence
implies the existence of AME states for an arbitrary number of parties based on
known results about the existence of quantum secret sharing schemes.Comment: 5 pages, 2 figure
Longitudinal Eigenvibration of Multilayer Colloidal Crystals and the Effect of Nanoscale Contact Bridges
Longitudinal contact-based vibrations of colloidal crystals with a controlled
layer thickness are studied. These crystals consist of 390 nm diameter
polystyrene spheres arranged into close packed, ordered lattices with a
thickness of one to twelve layers. Using laser ultrasonics, eigenmodes of the
crystals that have out-of-plane motion are excited. The particle-substrate and
effective interlayer contact stiffnesses in the colloidal crystals are
extracted using a discrete, coupled oscillator model. Extracted stiffnesses are
correlated with scanning electron microscope images of the contacts and atomic
force microscope characterization of the substrate surface topography after
removal of the spheres. Solid bridges of nanometric thickness are found to
drastically alter the stiffness of the contacts, and their presence is found to
be dependent on the self-assembly process. Measurements of the eigenmode
quality factors suggest that energy leakage into the substrate plays a role for
low frequency modes but is overcome by disorder- or material-induced losses at
higher frequencies. These findings help further the understanding of the
contact mechanics, and the effects of disorder in three-dimensional micro- and
nano-particulate systems, and open new avenues to engineer new types of micro-
and nanostructured materials with wave tailoring functionalities via control of
the adhesive contact properties
Final Science Reports of the US Experiments Flown on the Russian Biosatellite Cosmos 2229
Cosmos 2229 was launched on December 29, 1992, containing a biological payload including two young male rhesus monkeys, insects, amphibians, and cell cultures. The biosatellite was launched from the Plesetsk Cosmodrome in Russia for a mission duration of 11.5 days. The major research objectives were: (1) Study of adaptive response mechanisms of mammals during flight; and (2) Study of physiological mechanisms underlying vestibular, motor system and brain function in primates during early and later adaptation phases. American scientists and their Russian collaborators conducted 11 experiments on this mission which included extensive preflight and postflight studies with rhesus monkeys. Biosamples and data were subsequently transferred to the United States. The U.S. responsibilities for this flight included the development of experiment protocols, the fabrication of some flight instrumentation and experiment-specific ground-based hardware, the conducting of preflight and postflight testing and the analysis of biospecimens and data for the U.S. experiments. A description of the Cosmos 2229 mission is presented in this report including preflight, on-orbit and postflight activities. The flight and ground-based bioinstrumentation which was developed by the U.S. and Russia is also described, along with the associated preflight testing ot the U.S. hardware. Final Science Reports for the experiments are also included
Vigor, vitality and seed dormancy of Avena sativa cultivars in a long-term experiment
Vigor, vitality and seed dormancy of 14 Finnish cultivars of Avena sativa in room temperature were studied in a 22-year laboratory experiment. These parameters were studied by measuring morphological and physical characteristics of seeds and by basic germination and enzymatic tests 1, 4, 6, 11, 16, 21 and 22 years after seed harvesting in 1989. Methylene blue, Congo red and 2,3,5-triphenyltetrazolium chloride (TZ) tests were used to estimate seed quality and changes in vitality over time. Seed vitality clearly decreased in all cultivars during the experiment. The mean vitality declined from 96.3% (one year after harvest) to zero at the end. Vitality according to the TZ test was higher than indicated by the basic germination test. The mean vitality loss was 4.6% per year, but there were clear differences between cultivars. The decrease in vitality correlated with loss in seed weight. Clear signs of deepening dormancy were observed. Seed age is an important factor infl uencing vitality and dormancy. Vitality loss of seeds led to deep dormancy. The appearance, water uptake and imbibition of the seeds remained normal until the end. Ageing, vitality loss and dormancy are concluded to be expressions of genes. It is possible that in the future electronic simulation methods will be developed that will enable accurate estimation of oat seed quality without laboratory tests
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