5,402 research outputs found
Ultrafast dynamics of a magnetic antivortex - Micromagnetic simulations
The antivortex is a fundamental magnetization structure which is the
topological counterpart of the well-known magnetic vortex. We study here the
ultrafast dynamic behavior of an isolated antivortex in a patterned Permalloy
thin-film element. Using micromagnetic simulations we predict that the
antivortex response to an ultrashort external field pulse is characterized by
the production of a new antivortex as well as of a temporary vortex, followed
by an annihilation process. These processes are complementary to the recently
reported response of a vortex and, like for the vortex, lead to the reversal of
the orientation of the antivortex core region. In addition to its fundamental
interest, this dynamic magnetization process could be used for the generation
and propagation of spin waves for novel logical circuits.Comment: 4 pages, 4 figures. To be published in Physical Review B (R
Correction to: Ten years malaria trend at Arjo-Didessa sugar development site and its vicinity, Southwest Ethiopia: a retrospective study.
Following publication of the original article [1], it came to the authors' attention that unfortunately the last name of one of the authors is spelled incorrectly in the published article
A contact formulation based on a volumetric potential: Application to isogeometric simulations of atrioventricular valves
This work formulates frictionless contact between solid bodies in terms of a repulsive potential energy term and illustrates how numerical integration of the resulting forces is computationally similar to the “pinball algorithm” proposed and studied by Belytschko and collaborators in the 1990s. We thereby arrive at a numerical approach that has both the theoretical advantages of a potential-based formulation and the algorithmic simplicity, computational efficiency, and geometrical versatility of pinball contact. The singular nature of the contact potential requires a specialized nonlinear solver and an adaptive time stepping scheme to ensure reliable convergence of implicit dynamic calculations. We illustrate the effectiveness of this numerical method by simulating several benchmark problems and the structural mechanics of the right atrioventricular (tricuspid) heart valve. Atrioventricular valve closure involves contact between every combination of shell surfaces, edges of shells, and cables, but our formulation handles all contact scenarios in a unified manner. We take advantage of this versatility to demonstrate the effects of chordal rupture on tricuspid valve coaptation behavior
Green Building Rating Systems and Construction Waste in High Density Urban Environment: The Case Study of Hong Kong
Hong Kong, as many other countries, is currently facing a waste management crisis with the shortage of reclamation sites and landfill space. Examination of construction waste management (CWM) criteria within Hong Kong’s BEAM Plus is limited and lacking. In this paper, CWM criteria were assessed and a case study was conducted on a recent project, pursuing BEAM Plus, to assess the effectiveness of CWM criteria to facilitate waste reduction. The findings revealed that the overall impact of BEAM Plus on construction waste reduction is negligible. The case study showed that the reasons material/waste-related credits are not commonly attempted is due to the lack of minimum thresholds and a low weighting relative to credits in other categories. In the case study, waste generated per constructed floor area was 0.21 tons/m2. This paper also makes recommendations to improve CWM criteria in BEAM Plus in order to promote a more sustainable building industry
1-(4-Methylphenyldiazoniumyl)-2-naphtholate
In the title compound, C17H14N2O, the dihedral angle between the benzene ring and naphthalene ring system is 11.0 (3)°. The azo group adopts an anti configuration and an intramolecular N—H⋯O hydrogen bond exists. Molecules are packed by π–π interactions between adjacent molecule (closest approach between centroids of benzene and naphthalene rings of 3.501 Å)
The impact of long-lasting microbial larvicides in reducing malaria transmission and clinical malaria incidence: study protocol for a cluster randomized controlled trial.
BACKGROUND: The massive scale-up of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) has led to a substantial increase in malaria vector insecticide resistance as well as in increased outdoor transmission, both of which hamper the effectiveness and efficiency of ITN and IRS. Long-lasting microbial larvicide can be a cost-effective new supplemental intervention tool for malaria control. METHODS/DESIGN: We will implement the long-lasting microbial larvicide intervention in 28 clusters in two counties in western Kenya. We will test FourStar controlled release larvicide (6 % by weight Bacillus thuringiensis israelensis and 1 % Bacillus sphaerius) by applying FourStar controlled release granule formulation, 90-day briquettes, and 180-day briquettes in different habitat types. The primary endpoint is clinical malaria incidence rate and the secondary endpoint is malaria vector abundance and transmission intensity. The intervention will be conducted as a two-step approach. First, we will conduct a four-cluster trial (two clusters per county, with one of the two clusters randomly assigned to the intervention arm) to optimize the larvicide application scheme. Second, we will conduct an open-label, cluster-randomized trial to evaluate the effectiveness and cost-effectiveness of the larvicide. Fourteen clusters in each county will be assigned to intervention (treatment) or no intervention (control) by a block randomization on the basis of clinical malaria incidence, vector density, and human population size per site. We will treat each treatment cluster with larvicide for three rounds at 4-month intervals, followed by no treatment for the following 8 months. Next, we will switch the control and treatment sites. The former control sites will receive three rounds of larvicide treatment at appropriate time intervals, and former treatment sites will receive no larvicide. We will monitor indoor and outdoor vector abundance using CO2-baited CDC light traps equipped with collection bottle rotators. Clinical malaria data will be aggregated from government-run malaria treatment centers. DISCUSSION: Since current first-line vector intervention methods do not target outdoor transmission and will select for higher insecticide resistance, new methods beyond bed nets and IRS should be considered. Long-lasting microbial larviciding represents a promising new tool that can target both indoor and outdoor transmission and alleviate the problem of pyrethroid resistance. It also has the potential to diminish costs by reducing larvicide reapplications. If successful, it could revolutionize malaria vector control in Africa, just as long-lasting bed nets have done. TRIAL REGISTRATION: U.S. National Institute of Health, study ID NCT02392832 . Registered on 3 February 2015
Resonance in modulation instability from non-instantaneous nonlinearities
To explore resonance phenomena in the nonlinear region, we show by
experimental measurements and theoretical analyses that resonance happens in
modulation instability (MI) from non-instantaneous nonlinearities in
photorefractive crystals. With a temporally periodic modulation in the external
bias voltage, corresponding to a modulation in the nonlinear strength, an
enhancement in the visibility of MI at resonant frequency is reported through
spontaneous optical pattern formations. Modeled by such temporally periodic
nonlinear driving force to the system, theoretical curves obtained from a
nonlinear non-instantaneous Schr\"{o}dinger equation give good agreement to
experimental data. As MI is a universal signature of symmetry-breaking
phenomena, our observation on the resonance in MI may provide a control on
chaotic, solitary, and turbulence waves.Comment: 5 pages, 4 figure
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