35,289 research outputs found
Seasonal Flight Patterns of Miridae (Hemiptera) in a Southern Illinois Black Walnut Plantation
The seasonal flight patterns of 92 species of Miridae collected in window traps in a southern Illinois black walnut plantation are compared with similar data from a North Carolina black walnut plantation. Flying height distributions and seasonal flight activities of Amblytylus nasutus, Deraeocoris nebulosus, Leptopterna dolabrata, Lopidea heidemanni, Lygus lineolaris, and Plagiognathus politus are considered in detail. Six species are newly recorded for Illinois
Tropidosteptes forestierae (Hemiptera: Heteroptera: Miridae: Mirinae): a new species of Plant Bug injuring ornamental Florida Swampprivet, Forestiera segregata (Oleaceae), in South Florida
The mirine plant bug Tropidosteptes forestierae, new species (Hemiptera: Miridae) is described from
Collier County, Florida, where it was found causing serious injury to an extensive ornamental hedge of Florida swampprivet, Forestiera segregata (Jacq.) Krug and Urb. (Oleaceae). Adult male and female, fifth instar, and egg are described. Color images of the adults, nymph, egg, and injury; scanning photomicrographs of selected adult structures; and illustrations of male genitalia are provided. A key to help distinguish the 16 species of Tropidosteptes known to occur in the southeastern United States is given
The Stellar Activity - Rotation Relationship
Using a new catalog of 824 solar and late-type stars with X-ray luminosities
and rotation periods we have studied the relationship between rotation and
stellar activity. From an unbiased subset of this sample the power law slope of
the unsaturated regime, , is fit as
. This is inconsistent with the canonical slope
to a confidence of 5 and argues for an interface-type dynamo.
Super-saturation is observed for the fastest rotators in our sample and its
parametric dependencies are explored. Significant correlations are found with
both the corotation radius and the excess polar updraft, the latter theory
being supported by other observations. We also present a new X-ray population
synthesis model of the mature stellar component of our Galaxy and use it to
reproduce deep observations of a high Galactic latitude field. The model,
XStar, can be used to test models of stellar spin-down and dynamo decay, as
well as for estimating stellar X-ray contamination rates for non-stellar
studies.Comment: 4 pages, 4 figures. To appear in the proceedings of Cool Stars 17:
17th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, AN 334,
1-2, Eds Klaus Strassmeier and Mercedes Lopez-Morale
Flight test results for a separate surface stability augmented Beech model 99
A flight evaluation of a Beech model 99 equipped with an attitude command control system incorporating separate surface stability augmentation (SSSA) was conducted to determine whether an attitude command control system could be implemented using separate surface controls, and to determine whether the handling and ride qualities of the aircraft were improved by the SSSA attitude command system. The results of the program revealed that SSSA is a viable approach to implementing attitude command and also that SSSA has the capability of performing less demanding augmentation tasks such as yaw damping, wing leveling, and pitch damping. The program also revealed that attitude command did improve the pilot rating and ride qualities of the airplane while flying an IFR mission in turbulence. Some disadvantages of the system included the necessity of holding aileron force in a banked turn and excessive stiffness in the pitch axis
Steric engineering of metal-halide perovskites with tunable optical band gaps
Owing to their high energy-conversion efficiency and inexpensive fabrication
routes, solar cells based on metal-organic halide perovskites have rapidly
gained prominence as a disruptive technology. An attractive feature of
perovskite absorbers is the possibility of tailoring their properties by
changing the elemental composition through the chemical precursors. In this
context, rational in silico design represents a powerful tool for mapping the
vast materials landscape and accelerating discovery. Here we show that the
optical band gap of metal-halide perovskites, a key design parameter for solar
cells, strongly correlates with a simple structural feature, the largest
metal-halide-metal bond angle. Using this descriptor we suggest continuous
tunability of the optical gap from the mid-infrared to the visible. Precise
band gap engineering is achieved by controlling the bond angles through the
steric size of the molecular cation. Based on these design principles we
predict novel low-gap perovskites for optimum photovoltaic efficiency, and we
demonstrate the concept of band gap modulation by synthesising and
characterising novel mixed-cation perovskites.Comment: This manuscript was submitted for publication on March 6th, 2014.
Many of the results presented in this manuscript were presented at the
International Conference on Solution processed Semiconductor Solar Cells,
held in Oxford, UK, on 10-12 September 2014. The manuscript is 37 pages long
and contains 8 figure
Identification of the X-ray pulsar in Hercules: A new optical pulsar
A series of photographic, photoelectric, and spectroscopic observations beginning June 1, 1972 has led to the optical identification of Her X-1 (2U 1705 + 34), a pulsed X-ray source in an eclipsing binary system, with the thirteenth magnitude blue variable star HZ Herculis. The detection of optical pulses at the frequency of the X-ray pulsar on three nights makes the identification conclusive and establishes HZ Her as the second known optical pulsar. The strength of the optical pulses may be correlated with the orbital phase but is not obviously related to the high or low intensity states of the X-ray source
Late diagenetic indicators of buried oil and gas. 2: Direct detection experiment at Cement and Garza fields, Oklahoma and Texas, using enhanced LANDSAT 1 and 2 images
The author has identified the following significant results. The Cement oil field, Oklahoma, was a test site for an experiment designed to evaluate LANDSAT's capability to detect an alteration zone in surface rocks caused by hydrocarbon microseepage. Loss of iron and impregnation of sandstone by carbonate cements and replacement of gypsum by calcite were the major alteration phenomena at Cement. The bedrock alterations were partially masked by unaltered overlying beds, thick soils, and dense natural and cultivated vegetation. Interpreters, biased by detailed ground truth, were able to map the alteration zone subjectively using a magnified, filtered, and sinusoidally stretched LANDSAT composite image; other interpreters, unbiased by ground truth data, could not duplicate that interpretation
Evaluation of directionally solidified eutectic superalloys for turbine blade applications
Alloys from the following systems were selected for property evaluation: (1) gamma/gamma-Mo (Ni-base, rods of Mo); (2) gamma-beta (Ni-base, lamellae or rods of (Ni, Fe/Co Al); and (3) gamma-gamma (Ni-base rods of Ni3Al gamma). The three alloys were subjected to longitudinal and transverse tensile and rupture tests from 750 C to 1100 C, longitudinal shear strength was measured at several temperatures, resistance to thermal cycling to 1150 C was determined, cyclic oxidation resistance was evaluated at 750 C and 1100 C, and each system was directionally solidified in an alumina shell mold turbine shape to evaluate mold/metal reactivity. The gamma/gamma Mo system has good rupture resistance, transverse properties and processability, and is a high potential system for turbine blades. The gamma-beta system has good physical properties and oxidation resistance, and is a potential system for turbine vanes. The gamma-gamma system has good high temperature rupture resistance and requires further exploratory research
Role of the surface in the measurement of the Leidenfrost temperature
Role of surfaces in measuring Leidenfrost temperatur
- …