247 research outputs found
HMAP Dataset 15: Galapagos Marine Reserve, Ecuador III
Catch and effort statistics, sea cucumber, spiny lobster and finfish fisheries since 1961
New records of biting midges of the genus Culicoides Latreille from Mexico (Diptera: Ceratopogonidae)
We provide the first records of six species of biting midges (Diptera: Ceratopogonidae) in the genus
Culicoides Latreille from Mexico: C. baueri Hoffman, C. castillae Fox, C. debilipalpis Lutz, C. iriartei Fox, C. leoni
Barbosa and C. pusilloides Wirth and Blanton. In addition, C. leopoldoi Ortiz is confirmed from Mexico, and new
records are included for 25 other species previously recorded in Mexico: C. arubae Fox and Hoffman, C. blantoni Vargas
and Wirth, C. crepuscularis Malloch, C. daedalus Macfie, C. diabolicus Hoffman, C. foxi Ortiz, C. furens (Poey), C.
gabaldoni Ortiz, C. haematopotus Malloch, C. hylas Macfie, C. insignis Lutz, C. jamaicensis Edwards, C. luteovenus
Root and Hoffman, C. neopulicaris Wirth, C. nigrigenus Wirth and Blanton, C. pampoikilus Macfie, C. panamensis
Barbosa, C. paraensis (Goeldi), C. phlebotomus (Williston), C. poikilonotus Macfie, C. pusillus Lutz, C. stigmalis Wirth,
and all three species in the C. (Monoculicoides) variipennis complex, C. variipennis (Coquillett), C. occidentalis Wirth
and Jones, and C. sonorensis Wirth and Jones
HMAP Dataset 14: Galapagos Marine Reserve, Ecuador II
Catch and effort statistics, sea cucumber, spiny lobster and finfish fisheries since 1961
HMAP Dataset 13: Galapagos Marine Reserve, Ecuador I
Catch and effort statistics, sea cucumber, spiny lobster and finfish fisheries since 1961
Controlled cavity collapse: scaling laws of drop formation
The formation of transient cavities at liquid interfaces occurs in an immense variety of natural processes, among which the bursting of surface bubbles and the impact of a drop on a liquid pool are salient. The collapse of a surface liquid cavity is a well documented natural process that leads to the ejection of a thin and fast jet. Droplets generated through this process can be one order of magnitude smaller than the cavity's aperture, and they are consequently of interest in drop on demand inkjet applications. In this work, the controlled formation and collapse of a liquid cavity is analyzed, and the conditions for minimizing the resulting size and number of ejected drops are determined. The experimental and numerical models are simple and consist of a liquid reservoir, a nozzle plate with the discharge orifice, and a moving piston actuated by single half-sine-shaped pull-mode pulses. The size of the jetted droplet is described by a physical model resulting in a scaling law that is numerically and experimentally validatedRoyal Society (UF120319, URF\R\180016, and RGF\EA\180061)John Fell Oxford University Press Research Fund (0005176)EPSRC – UK (EP/P024173/1)Ministerio de Economía y Competitividad, Plan Estatal 2013–2016 Retos, project DPI2013-46485-C3-1-
It's Harder to Splash on Soft Solids
Droplets splash when they impact dry, flat substrates above a critical
velocity that depends on parameters such as droplet size, viscosity and air
pressure. By imaging ethanol drops impacting silicone gels of different
stiffnesses we show that substrate stiffness also affects the splashing
threshold. Splashing is reduced or even eliminated: droplets on the softest
substrates need over 70\% more kinetic energy to splash than they do on rigid
substrates. We show that this is due to energy losses caused by deformations of
soft substrates during the first few microseconds of impact. We find that
solids with Young's moduli kPa reduce splashing, in agreement
with simple scaling arguments. Thus materials like soft gels and elastomers can
be used as simple coatings for effective splash prevention. Soft substrates
also serve as a useful system for testing splash-formation theories and
sheet-ejection mechanisms, as they allow the characteristics of ejection sheets
to be controlled independently of the bulk impact dynamics of droplets.Comment: 5 pages, 4 figure
Plethora of transitions during breakup of liquid filaments.
Thinning and breakup of liquid filaments are central to dripping of leaky faucets, inkjet drop formation, and raindrop fragmentation. As the filament radius decreases, curvature and capillary pressure, both inversely proportional to radius, increase and fluid is expelled with increasing velocity from the neck. As the neck radius vanishes, the governing equations become singular and the filament breaks. In slightly viscous liquids, thinning initially occurs in an inertial regime where inertial and capillary forces balance. By contrast, in highly viscous liquids, initial thinning occurs in a viscous regime where viscous and capillary forces balance. As the filament thins, viscous forces in the former case and inertial forces in the latter become important, and theory shows that the filament approaches breakup in the final inertial-viscous regime where all three forces balance. However, previous simulations and experiments reveal that transition from an initial to the final regime either occurs at a value of filament radius well below that predicted by theory or is not observed. Here, we perform new simulations and experiments, and show that a thinning filament unexpectedly passes through a number of intermediate transient regimes, thereby delaying onset of the inertial-viscous regime. The new findings have practical implications regarding formation of undesirable satellite droplets and also raise the question as to whether similar dynamical transitions arise in other free-surface flows such as coalescence that also exhibit singularities.The authors thank Dr. Pankaj Doshi for several insightful discussions. This work was supported by the Basic Energy Sciences program of the US Department of Energy (DE-FG02-96ER14641), Procter & Gamble USA, the Chevron Corporation, the UK Engineering and Physical Sciences Research Council (Grant EP/H018913/1), the John Fell Oxford University Press Research Fund, and the Royal Society.This is the final published version. It first appeared via PNAS at http://dx.doi.org/10.1073/pnas.141854111
New records of biting midges of the genus \u3ci\u3eCulicoides\u3c/i\u3e Latreille from Mexico (Diptera: Ceratopogonidae)
We provide the first records of six species of biting midges (Diptera: Ceratopogonidae) in the genus Culicoides Latreille from Mexico: C. baueri Hoffman, C. castillae Fox, C. debilipalpis Lutz, C. iriartei Fox, C. leoni Barbosa and C. pusilloides Wirth and Blanton. In addition, C. leopoldoi Ortiz is confirmed from Mexico, and new records are included for 25 other species previously recorded in Mexico: C. arubae Fox and Hoffman, C. blantoni Vargas and Wirth, C. crepuscularis Malloch, C. daedalus Macfie, C. diabolicus Hoffman, C. foxi Ortiz, C. furens (Poey), C. gabaldoni Ortiz, C. haematopotus Malloch, C. hylas Macfie, C. insignis Lutz, C. jamaicensis Edwards, C. luteovenus Root and Hoffman, C. neopulicaris Wirth, C. nigrigenus Wirth and Blanton, C. pampoikilus Macfie, C. panamensis Barbosa, C. paraensis (Goeldi), C. phlebotomus (Williston), C. poikilonotus Macfie, C. pusillus Lutz, C. stigmalis Wirth, and all three species in the C. (Monoculicoides) variipennis complex, C. variipennis (Coquillett), C. occidentalis Wirth and Jones, and C. sonorensis Wirth and Jones
Effect of antimony content on electrical and structural properties of 0.98(K0.48Na0.52)0.95Li0.05Nb1−Sb O3–0.02Ba0.5(Bi0.5Na0.5)0.5ZrO3 ceramics
Lead-free 0.98(K0.48Na0.52)0.95Li0.05Nb1−xSbxO3–0.02Ba0.5(Bi0.5Na0.5)0.5ZrO3 (KNLNSx–BBNZ)solid solution with 0.04 < x < 0.08 was prepared by traditional solid-state process. Sampleswere sintered using a conventional method at 1120 ◦C for 4h. The effect of Sb5+ content onthe phase structure, microstructure, ferroelectric, dielectric and piezoelectric properties ofthe KNLNSx–BBNZ ceramics was studied. The phase transition of the ceramic was determined by the temperature dependence of the dielectric properties, while the structuralproperties, like the phase coexistence, were studied by X-ray diffraction. It was found thatceramics in the composition range of 0.06 < x < 0.08 possess an orthorhombic (Amm2) andtetragonal (P4mm) phases coexistence. The best piezoelectric properties were obtained inthe ceramics with x = 0.07: d33 = 282 pC/N, −d31 = 103 pC/N, kp = 46%, εr = 1820, tanı = 3% andTc = 271 ◦C. Furthermore, this composition exhibited a good thermal stability, up to 200 ◦C ond33 piezoelectric constant, indicating that this material have great potential for applicationfrom room temperature until this temperature limit
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