88 research outputs found
«Mit dem Pflanzen von Bäumen halten wir den Klimawandel nicht auf»
Es gebe in Schweizer Städten gute Projekte zur Anpassung an den Klimawandel, sagt William Fuhrer, Professor für Urbane Entwicklung und Mobilität. Allerdings brauche es grössere Anstrengungen, um seine Ursachen zu bekämpfen. «Dazu müssten Prozesse in der Raumplanung vereinfacht und verkürzt werden.
Princess and the Pea at the nanoscale: Wrinkling and delamination of graphene on nanoparticles
Thin membranes exhibit complex responses to external forces or geometrical
constraints. A familiar example is the wrinkling, exhibited by human skin,
plant leaves, and fabrics, resulting from the relative ease of bending versus
stretching. Here, we study the wrinkling of graphene, the thinnest and stiffest
known membrane, deposited on a silica substrate decorated with silica
nanoparticles. At small nanoparticle density monolayer graphene adheres to the
substrate, detached only in small regions around the nanoparticles. With
increasing nanoparticle density, we observe the formation of wrinkles which
connect nanoparticles. Above a critical nanoparticle density, the wrinkles form
a percolating network through the sample. As the graphene membrane is made
thicker, global delamination from the substrate is observed. The observations
can be well understood within a continuum elastic model and have important
implications for strain-engineering the electronic properties of graphene.Comment: 11 pages, 8 figures. Accepted for publication in Physical Review
Composite intersection reinforcement
An assembly and method for manufacturing a composite reinforcement for unitizing a structure are provided. According to one embodiment, the assembly includes a base having a plurality of pins extending outwardly therefrom to define a structure about which a composite fiber is wound to define a composite reinforcement preform. The assembly also includes a plurality of mandrels positioned adjacent to the base and at least a portion of the composite reinforcement preform, and a cap that is positioned over at least a portion of the plurality of mandrels. The cap is configured to engage each of the mandrels to support the mandrels and the composite reinforcement preform during a curing process to form the composite reinforcement
Composite Intersection Reinforcement
An assembly and method for manufacturing a composite reinforcement for unitizing a structure are provided. According to one embodiment, the assembly includes a base having a plurality of pins extending outwardly therefrom to define a structure about which a composite fiber is wound to define a composite reinforcement preform. The assembly also includes a plurality of mandrels positioned adjacent to the base and at least a portion of the composite reinforcement preform, and a cap that is positioned over at least a portion of the plurality of mandrels. The cap is configured to engage each of the mandrels to support the mandrels and the composite reinforcement preform during a curing process to form the composite reinforcement
High-fidelity conformation of graphene to SiO2 topographic features
Strain engineering of graphene through interaction with a patterned substrate
offers the possibility of tailoring its electronic properties, but will require
detailed understanding of how graphene's morphology is determined by the
underlying substrate. However, previous experimental reports have drawn
conflicting conclusions about the structure of graphene on SiO2. Here we show
that high-resolution non-contact atomic force microscopy of SiO2 reveals
roughness at the few-nm length scale unresolved in previous measurements, and
scanning tunneling microscopy of graphene on SiO2 shows it to be slightly
smoother than the supporting SiO2 substrate. Quantitative analysis of the
competition between bending rigidity of the graphene and adhesion to the
substrate explains the observed roughness of monolayer graphene on SiO2 as
extrinsic, and provides a natural, intuitive description in terms of highly
conformal adhesion. The analysis indicates that graphene adopts the
conformation of the underlying substrate down to the smallest features with
nearly 99% fidelity.Comment: 13 pages, 3 figures plus supplemental informatio
Ebola virus disease in West Africa — the first 9 Months of the epidemic and forward projections
BACKGROUND
On March 23, 2014, the World Health Organization (WHO) was notified of an outbreak of Ebola virus disease (EVD) in Guinea. On August 8, the WHO declared the epidemic to be a "public health emergency of international concern."
METHODS
By September 14, 2014, a total of 4507 probable and confirmed cases, including 2296 deaths from EVD (Zaire species) had been reported from five countries in West Africa - Guinea, Liberia, Nigeria, Senegal, and Sierra Leone. We analyzed a detailed subset of data on 3343 confirmed and 667 probable Ebola cases collected in Guinea, Liberia, Nigeria, and Sierra Leone as of September 14.
RESULTS
The majority of patients are 15 to 44 years of age (49.9% male), and we estimate that the case fatality rate is 70.8% (95% confidence interval [CI], 69 to 73) among persons with known clinical outcome of infection. The course of infection, including signs and symptoms, incubation period (11.4 days), and serial interval (15.3 days), is similar to that reported in previous outbreaks of EVD. On the basis of the initial periods of exponential growth, the estimated basic reproduction numbers (R-0) are 1.71 (95% CI, 1.44 to 2.01) for Guinea, 1.83 (95% CI, 1.72 to 1.94) for Liberia, and 2.02 (95% CI, 1.79 to 2.26) for Sierra Leone. The estimated current reproduction numbers (R) are 1.81 (95% CI, 1.60 to 2.03) for Guinea, 1.51 (95% CI, 1.41 to 1.60) for Liberia, and 1.38 (95% CI, 1.27 to 1.51) for Sierra Leone; the corresponding doubling times are 15.7 days (95% CI, 12.9 to 20.3) for Guinea, 23.6 days (95% CI, 20.2 to 28.2) for Liberia, and 30.2 days (95% CI, 23.6 to 42.3) for Sierra Leone. Assuming no change in the control measures for this epidemic, by November 2, 2014, the cumulative reported numbers of confirmed and probable cases are predicted to be 5740 in Guinea, 9890 in Liberia, and 5000 in Sierra Leone, exceeding 20,000 in total.
CONCLUSIONS
These data indicate that without drastic improvements in control measures, the numbers of cases of and deaths from EVD are expected to continue increasing from hundreds to thousands per week in the coming months
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