15,298 research outputs found
Assessing Ageing Condition of Mineral Oil-Paper Insulation by Polarization/Depolarization Current
Accurately assessing the ageing status of oil-paper insulation in transformer is essential and important. Polarization and Depolarization Current (PDC) technique is effective in assessing the condition of oil-paper insulation system. Though the PDC behaviour of mineral oil-paper insulation has been widely investigated, there is no report about how to make the quantitative analysis of mineral oil-paper insulation ageing condition by PDC. The PDC characteristics of mineral oil-paper insulation samples were investigated over the ageing period at 110°C. A new method for assessing the ageing condition of mineral oil-paper insulation by calculating the depolarization charge quantity was proposed. Results show that the depolarization charge quantity of mineral oil-paper insulation sample is very sensitive to its ageing condition. The stable depolarization charge quantity could be used to predict the ageing condition of mineral oil-paper insulation
Localized Control of Curie Temperature in Perovskite Oxide Film by Capping-layer- induced Octahedral Distortion
With reduced dimensionality, it is often easier to modify the properties of
ultra-thin films than their bulk counterparts. Strain engineering, usually
achieved by choosing appropriate substrates, has been proven effective in
controlling the properties of perovskite oxide films. An emerging alternative
route for developing new multifunctional perovskite is by modification of the
oxygen octahedral structure. Here we report the control of structural oxygen
octahedral rotation in ultra-thin perovskite SrRuO3 films by the deposition of
a SrTiO3 capping layer, which can be lithographically patterned to achieve
local control. Using a scanning Sagnac magnetic microscope, we show increase in
the Curie temperature of SrRuO3 due to the suppression octahedral rotations
revealed by the synchrotron x-ray diffraction. This capping-layer-based
technique may open new possibilities for developing functional oxide materials.Comment: Main-text 5 pages, SI 6 pages. To appear in Physical Review Letter
High-capacity wave energy conversion by multi-floats, multi-PTO, control and prediction: generalised state-space modelling with linear optimal control and arbitrary headings
Wave energy converters with capacity similar to, or greater than, wind turbines are desirable for the supply of electricity to the grid. It is shown that this may be provided by multiple floats in a hinged raft-type configuration with multimode forcing. The case analysed has 8 floats and 4 power take off (PTO) units. Analysis is based on linear diffraction-radiation modelling, validated in wave basin experiments with a smaller number of floats. Control is desirable to improve energy capture, mainly demonstrated for point absorbers, but this has not previously been applied to such a complex problem with many freedoms. The linear hydrodynamic model in a state-space form makes it possible to implement advanced control algorithms in real time. Linear non-causal optimal control (LNOC) is applied with wave force prediction from auto-regression. For the design case with zero heading, as the configuration heads naturally into the wave direction, energy capture is improved by between 21% and 83%. The energy capture is about 62% the maximum possible from idealised analyses. Off-design, non-zero headings are also analysed to indicate how energy capture can be reduced; this is again improved by control, by several times at 90 degrees heading
Plant regeneration system from cotyledons-derived calluses cultures of Stylosanthes guianensis cv. âReyan 2â
The objective of this study was to successfully establish plant regeneration system with cotyledons of Stylosanthes guianensis Sw. cv. âReyan 2â as explants. In this study, the following results were obtained; (1) the highest rates of callus induction on medium MS with 3.0 mg L-1 2, 4-D with cotyledons as explants were 74%. The above medium of formulation was adopted for subculture; (2) the highest rates of callus differentiation medium MS with 3.0 mg L-1 6-BA with cotyledons as explants was 66%; (3) the optimum medium of shoot growth was MS medium plus 1.0 mg L-1 6-BA, 0.5 mg L-1 NAA and 0.4 mg L-1 GA; (4) the rooting rate was 60% on optimum rooting medium with 0.2 mg L-1 NAA; (5) the survival rate of plant transplanting was 70% after transferred to pots with garden soil. In conclusion, the efficient plant regeneration system developed here will be helpful for rapid micropropagation and further genetic improvement in S. guianensis Sw. cv. âReyan 2â.Key words: Stylosanthes guianensis Sw. cv. Reyan 2, callus, cotyledons, plant regeneration
Static Potentials and the Magnetic Component of QCD Plasma near
Static quark-anti-quark potential encodes important information on the
chromodynamical interaction between color charges, and recent lattice results
show its very nontrivial behavior near the deconfinement temperature . In
this paper we study such potential in the framework of the ``magnetic
scenario'' for the near Tc QCD plasma, and particularly focus on the linear
part (as quantified by its slope, the tension) in the potential as well as the
strong splitting between the free energy and internal energy. By using an
analytic ``ellipsoidal bag'' model, we will quantitatively relate the free
energy tension to the magnetic condensate density and relate the internal
energy tension to the thermal monopole density. By converting the lattice
results for static potential into density for thermal monopoles we find the
density to be very large around Tc and indicate at quantum coherence, in good
agreement with direct lattice calculation of such density. A few important
consequences for heavy ion collisions phenomenology will also be discussed.Comment: 10 pages, 6 figure
Distributed parameter estimation in unreliable sensor networks via broadcast gossip algorithms
In this paper, we present an asynchronous algorithm to estimate the unknown parameter under an unreliable network which allows new sensors to join and old sensors to leave, and can tolerate link failures. Each sensor has access to partially informative measurements when it is awakened. In addition, the proposed algorithm can avoid the interference among messages and effectively reduce the accumulated measurement and quantization errors. Based on the theory of stochastic approximation, we prove that our proposed algorithm almost surely converges to the unknown parameter. Finally, we present a numerical example to assess the performance and the communication cost of the algorithm.This work was supported in part by the National Natural Science Foundation of China under Grant 61503308 and Grant 61472331, in part by the Natural Science Foundation Project of Chongqing CSTC 2015jcyjA40043, and in part by Fundamental Research Funds for the Central Universities under Grant SWU114036. This publication was made possible by NPRP grant #4-1162-1-181 from the Qatar National Research Fund (a member of Qatar Foundation)
Documentation of a new hypotrich species in the family Amphisiellidae, Lamtostyla gui n. sp. (Protista, Ciliophora) using a multidisciplinary approach
An integrated approach considering both morphologic and molecular data is now required to improve biodiversity estimations and provide more robust systematics interpretations in hypotrichs, a highly differentiated group of ciliates. In present study, we document a new hypotrich species, Lamtostyla gui n. sp., collected from Chongming wetland, Shanghai, China, based on investigations using living observation, protargol staining, scanning and transmission electron microscopy, and gene sequencing. The new species is mainly recognized by having a short amphisiellid median cirral row composed of four cirri, three frontoventral cirri, three dorsal kinetids, four to eight macronuclear nodules, and small colorless cortical granules distributed as rosettes around dorsal bristles. Transmission electron microscope observation finds the associated microtubules of cirri and pharyngeal discs of L. gui are distinct from those in other hypotrichs. Morphogenesis of this species indicates that parental adoral membranelles retained intact or partial renewed is a potential feature to separate Lamtostyla granulifera-group and Lamtostyla lamottei-group. Phylogenetic analysis based on small subunit ribosomal RNA (rRNA) gene shows that this molecular marker is not useful to resolve phylogenetic relationships of the genus Lamtostyla, as well as many other hypotrichous taxa. We additionally characterize the internal transcribed spacers (ITS) region and the almost complete large subunit rRNA, which will be essential for future studies aimed at solving phylogenetic problems of Lamtostyla, or even the family Amphisiellidae. As a final remark, the critical screening of GenBank using ITS genes of our organism allows us to recognize a large amount of hypotrichous sequences have been misclassified as fungi. This observation suggests that hypotrichs could be frequently found in fungi-rich environment and overlooked by fungal specialists
L-Monomethyl-arginine decreases apoptosis of chondrocytes by altering Bax and Bcl-2 expression in osteoarthritis of rabbit knee
Previous studies found that NG-monomethyl-L-arginine (L-NMMA) treatment inhibits progression of osteoarthritis. Here, we aimed to explore the effects of L-NMMA on chondrocyte apoptosis and Bax and Bcl-2 mRNA expression in rabbits with knee osteoarthritis. Knee osteoarthritis was induced in 24 healthy rabbits by Hulth method, and rabbits were randomly divided into control (n = 12) and experimental (n = 12) groups. Once weekly, knee joints of control rabbits were injected with saline solution, while knees of experimental rabbits were injected with L-NMMA. Knee joint samples were collected after 6 weeks of treatment. Apoptosis of chondrocytes was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and Bax and Bcl-2 mRNA expression by in situ hybridization. The results show that the mean rate of chondrocyte apoptosis in knees of the experimental rabbits was significantly lower than that of the control rabbits (P<0.05). Additionally, Bax expression decreased and Bcl-2 expression increased in the experimental group (P<0.05). In brief, LNMMA can inhibit apoptosis of joint chondrocytes through changes in the expression of apoptosisrelated genes. Thus, this molecule offers the potential for treating osteoarthritis.Key words: NG-Monomethyl-L-arginine, knee osteoarthritis, chondrocyte, apoptosis-related regulatory gene
Optimal velocity loss threshold for inducing post activation potentiation in track and field athletes
The aim of this study was to determine the optimal velocity loss (VL) threshold that maximises the post activation potentiation (PAP) stimulus for achieving larger and more consistent performance gains in track and field athletes. Twenty-two athletes from athletics participated in four back squat PAP tests with four different VL threshold (5%, 10%, 15% and 20% VL) at an intensity of 85% 1RM. Countermovement jump (CMJ) height, power, and momentum were assessed before, and 10s, 4, 8, 12, 16 minutes after the PAP condition. Repetitions of the squat in all the PAP conditions were also recorded. Only the 5% VL condition produced significant improvements in height (ES=0.73, P=0.038), peak power output (ES=0.73, P=0.038) and momentum (ES=0.72, P=0.041) of CMJ, and these changes appeared 8 minutes after the condition. The total number of repetitions during the 5% VL condition was significantly lower than that observed in the 15% (P=0.003) and 20% VL (PïŒ0.001) trials. The results from this study indicate that 5%VL during the 2 sets preconditioning squat at 85%1RM was optimal for eliciting PAP in a CMJ exercise, and resulted in significant increases at the 8-min recovery period. The same squat condition also had the least number of repetitions. However, considering the efficiency in practice, athletes can also choose the rest time of 4-min, which can also achieve similar results
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