Mineralogy and petrology of comet 81P/wild 2 nucleus samples

The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Polymer Light-Emitting Electrochemical Cell Blends Based on Selection of Lithium Salts, LiX [X = Trifluoromethanesulfonate, Hexafluorophosphate, and Bis(trifluoromethylsulfonyl)imide] with Low Turn-On Voltage

Light-emitting electrochemical cell (LEEC) performance is drastically affected by the selection of suitable electrolyte. With the limited n-type doping in MEH-PPV near the cathodic interface, we hypothesized that anions in the electrolyte are critical to attain a higher conductivity p-doped area. Poly­(ethylene oxide)-lithium salts electrolyte systems have been investigated in the LEEC devices to determine the influence of anions on device turn-on voltage and operation. The TFSI^– anions showed higher resonance states, low turn-on voltages near the optical bandgap of the emissive conjugated polymer, high ionic conductivity in solid state (1.05 × 10^–4 S cm^–1), and larger electrochemical stability window compared to conventional CF₃SO₃^– anion. Device maximal brightness (∼100 cd/m²) can be achieved. Modulated differential scanning calorimetry (mDSC) studies of the polymer blend films correlate the thermal stability and doping effectiveness during operation and delineate the onset of degradation that entails burnout of the devices

Green synthesis of nanobelt-membrane hybrid structured vanadium oxide with high electrochromic contrast

Vanadium oxide with a nanobelt-membrane hybrid structure is synthesized under the structural directing effect from tannic acid, a green extract from plants. The electrochromic property of the resultant film was investigated and revealed a high contrast of 62% at the wavelength of 700 nm. Furthermore, with linear polyethylenimine (LPEI) surface treatment on ITO glass, the stability of the drop-casted film is greatly enhanced with only 18.6% reduction in transmission after 100 cycles.Published Versio