Evaluating the Environmental Performance of the U.S. Next Generation Air Transportation System

The environmental impacts of several possible U.S. Next Generation Air Transportation scenarios have been quantitatively evaluated for noise, air-quality, fuel-efficiency, and CO2 impacts. Three principal findings have emerged. (1) 2025 traffic levels about 30% higher than 2006 are obtained by increasing traffic according to FAA projections while also limiting traffic at each airport using reasonable ratios of demand to capacity. NextGen operational capabilities alone enable attainment of an additional 10-15% more flights beyond that 2025 baseline level with negligible additional noise, air-quality, and fuel-efficiency impacts. (2) The addition of advanced engine and airframe technologies provides substantial additional reductions in noise and air-quality impacts, and further improves fuel efficiency. 2025 environmental goals based on projected system-wide improvement rates of about 1% per year for noise and fuel-efficiency (an air-quality goal is not yet formulated) are achieved using this new vehicle technology. (3) Overall air-transport "product", as measured by total flown distance or total payload distance, increases by about 50% relative to 2006, but total fuel consumption and CO2 production increase by only about 40% using NextGen operational capabilities. With the addition of advanced engine/airframe technologies, the increase in total fuel consumption and CO2 production can be reduced to about 30%

High-field magnetotransport studies of surface-conducting diamonds

The observation of a strong and tunable spin-orbit interaction (SOI) in surface-conducting diamond opens up a new avenue for building diamond-based spintronics. Herein we provide a comprehensive method to analyze the magnetotransport behavior of surface-conducting hydrogen-terminated diamond (H-diamond) Hall bar devices and Al/Al2O3/V2O5/H-diamond metal-oxide semiconductor field-effect transistors, respectively. By adopting a significantly improved theoretical magnetotransport model, the reduced magnetoconductance can be accurately explained both within and outside the quantum diffusive regime. The model is valid for all doping strategies of surface-conducting diamond tested. From this analysis, we find that the orbital magnetoresistance, a classical effect distinct from the SOI, dominates the magnetotransport in surface-conducting diamond at high magnetic fields. Furthermore, local hole mobilities as high as 1000-3000cm2/Vs have been observed in this work, indicating the possibility of diamond-based electronics with ultrahigh hole mobilities at cryogenic temperatures.</p

Engineering the spin–orbit interaction in surface conducting diamond with a solid-state gate dielectric

Hydrogen-terminated (H-terminated) diamond, when surface transfer doped, can support a sub-surface two-dimensional (2D) hole band that possesses a strong Rashba-type spin–orbit interaction. By incorporating a V2O5/Al2O3 bilayer gate dielectric in a diamond-based metal–oxide–semiconductor architecture, metallic surface conductivity can be maintained at low temperature, avoiding the carrier freeze out exhibited by devices with an Al2O3 gate dielectric alone. Hole densities of up to 2.5 × 1013 cm−2 are achieved by the electrostatic gating of the device, and the spin–orbit interaction strength can be tuned from 3.5 ± 0.5 meV to 8.4 ± 0.5 meV, with a concurrent reduction in the spin coherence length from 40 ± 1 nm to 27 ± 1 nm. The demonstration of a gated device architecture on the H-terminated that avoids the need to cycle the temperature, as is required for ionic liquid gating protocols, opens a pathway to engineering practical devices for the study and application of spin transport in diamond

Low-noise diamond-based D.C. nano-SQUIDs

Nanoscale superconducting quantum interference devices (nano-SQUIDs) with Dayem bridge junctions and a physical loop size of 50 nm have been engineered in boron-doped nanocrystalline diamond films using precision Ne-ion beam milling. In an unshunted device, the nonhysteretic operation can be maintained in an applied field exceeding 0.1 T with a high flux-to-voltage transfer function, giving a low flux noise at 1 kHz and a concurrent spin sensitivity of . At elevated magnetic fields, up to 2 T, flux modulation of the nano-SQUID output voltage is maintained but with an increase in period, attributed to an additional phase bias induced on the nano-SQUID loop by up to 16 vortices per period penetrating the nano-SQUID electrodes

Strong spin-orbit interaction induced by transition metal oxides at the surface of hydrogen-terminated diamond

Hydrogen-terminated diamond possesses an intriguing p-type surface conductivity which is induced via thermodynamically driven electron transfer from the diamond surface into surface acceptors such as atmospheric adsorbates, a process called surface transfer doping. High electron affinity transition metal oxides (TMOs) including MoO3 and V2O5 have been shown to be highly effective solid-state surface acceptors for diamond, giving rise to a sub-surface two-dimensional (2D) hole layer with metallic conduction. In this work, low temperature magnetotransport is used as a tool to show the presence of a Rashba-type spin-orbit interaction with a high spin-orbit coupling of 19.9 meV for MoO3 doping and 22.9 meV for V2O5 doping, respectively, through the observation of a transition in the phase-coherent backscattering transport from weak localization to weak antilocalization at low temperature. Surface transfer doping of diamond with TMOs provides a 2D hole system with spin-orbit coupling that is over two times larger than that reported for diamond surfaces with atmospheric acceptors, opening up possibilities to study and engineer spin transport in a carbon material system.</p

High-electron-affinity oxide V2O5 enhances surface transfer doping on hydrogen-terminated diamond

Diamond exhibits many desirable properties that could benefit the development of future carbon-based electronic devices. Its hydrogen-terminated surface, in conjunction with a suitable surface acceptor, develops a two-dimensional (2D) p-type surface conductivity through the surface transfer doping mechanism which can then be harvested for constructing functional devices. In this study, we have revisited the surface transfer doping of diamond by a high electron affinity (EA) transition metal oxide, V2O5. Through a combination of in-situ electrical measurements, Hall effect measurements and first-principles density functional theory (DFT) calculations, we explicitly show the intrinsic surface transfer doping behavior of V2O5, with doping performance superior to other competing TMOs such as MoO3. The metallic surface conduction of diamond induced by V2O5 is persistent down to 250 mK; this when coupled with the high hole density exceeding 7 × 1013 cm−2 offers a promising platform for the development of advanced diamond surface electronics exploiting many interesting quantum transport properties of the 2D hole layer of diamond

Patient Complications after Interscalene Block: A Retrospective Comparison of Liposomal Bupivacaine to Nonliposomal Bupivacaine

Background. The purpose of this study was to investigate if the addition of liposome bupivacaine (LB) to an interscalene block (ISB) had an effect on the number of patients with surgical- or block-related complications. Methods. This was a single-center retrospective chart view performed by identifying patients who received an ISB from January 1, 2014, through April 26, 2018, at the University of Minnesota. 1,518 patients were identified who received an ISB (LB = 784, nonliposomal bupivacaine = 734). Patients were divided into two groups those who did receive liposome bupivacaine in their ISB and those who did not receive liposome bupivacaine in their ISB. Medical records were individually reviewed for surgical procedure, block medications, complications related to the block or surgical procedure, phone calls to the healthcare system for issues related to opioids or pain within 3 and within 30 days, readmissions within 30 days, and emergency room visits for complications within 3 and 30 days. Results. There was no significant difference in the number of patients with surgical or anesthetic complications. Only phone calls for pain within 3 days were significantly different. The LB group had 3.2% of patients call compared to 5.6% in the nonliposomal bupivacaine group (aOR = 1.71 (95% CI: 1.04–2.87), p=0.036). We found no significant difference in any of the other secondary outcomes. Conclusions. The use of LB in an ISB demonstrated no significant difference compared to nonliposomal bupivacaine in numbers of complications, emergency room visits, and readmissions