Parametric study of transport aircraft systems cost and weight

The results of a NASA study to develop production cost estimating relationships (CERs) and weight estimating relationships (WERs) for commercial and military transport aircraft at the system level are presented. The systems considered correspond to the standard weight groups defined in Military Standard 1374 and are listed. These systems make up a complete aircraft exclusive of engines. The CER for each system (or CERs in several cases) utilize weight as the key parameter. Weights may be determined from detailed weight statements, if available, or by using the WERs developed, which are based on technical and performance characteristics generally available during preliminary design. The CERs that were developed provide a very useful tool for making preliminary estimates of the production cost of an aircraft. Likewise, the WERs provide a very useful tool for making preliminary estimates of the weight of aircraft based on conceptual design information

Hierarchy of the Selberg zeta functions

We introduce a Selberg type zeta function of two variables which interpolates several higher Selberg zeta functions. The analytic continuation, the functional equation and the determinant expression of this function via the Laplacian on a Riemann surface are obtained.Comment: 14 page

Valence and Charge-transfer Optical Properties for Some Si\u3csub\u3en\u3c/sub\u3eC\u3csub\u3em\u3c/sub\u3e (m, n ≤ 12) Clusters: Comparing TD-DFT, Complete-basis-limit EOMCC, and Benchmarks from Spectroscopy

Accurate optical characterization of the closo-Si12C12 molecule is important to guide experimental efforts toward the synthesis of nano-wires, cyclic nano-arrays, and related array structures, which are anticipated to be robust and efficient exciton materials for opto-electronic devices. Working toward calibrated methods for the description of closo-Si12C12 oligomers, various electronic structure approaches are evaluated for their ability to reproduce measured optical transitions of the SiC2, Si2Cn (n = 1–3), and Si3Cn (n = 1, 2) clusters reported earlier by Steglich and Maier [Astrophys. J. 801, 119 (2015)]. Complete-basis-limit equation-of-motion coupled-cluster (EOMCC) results are presented and a comparison is made between perturbative and renormalized non-iterative triples corrections. The effect of adding a renormalized correction for quadruples is also tested. Benchmark test sets derived from both measurement and high-level EOMCC calculations are then used to evaluate the performance of a variety of density functionals within the time-dependent density functional theory (TD-DFT) framework. The best-performing functionals are subsequently applied to predict valence TD-DFT excitation energies for the lowest-energy isomers of SinC and Sin−1C7−n (n = 4–6). TD-DFT approaches are then applied to the SinCn (n = 4–12) clusters and unique spectroscopic signatures of closo-Si12C12 are discussed. Finally, various long-range corrected density functionals, including those from the CAM-QTP family, are applied to a charge-transfer excitation in a cyclic (Si4C4)4 oligomer. Approaches for gauging the extent of charge-transfer character are also tested and EOMCC results are used to benchmark functionals and make recommendations

The Decadal Climate Prediction Project (DCPP) contribution to CMIP6

The Decadal Climate Prediction Project (DCPP) is a coordinated multi-model investigation into decadal climate prediction, predictability, and variability. The DCPP makes use of past experience in simulating and predicting decadal variability and forced climate change gained from the fifth Coupled Model Intercomparison Project (CMIP5) and elsewhere. It builds on recent improvements in models, in the reanalysis of climate data, in methods of initialization and ensemble generation, and in data treatment and analysis to propose an extended comprehensive decadal prediction investigation as a contribution to CMIP6 (Eyring et al., 2016) and to the WCRP Grand Challenge on Near Term Climate Prediction (Kushnir et al., 2016). The DCPP consists of three components. Component A comprises the production and analysis of an extensive archive of retrospective forecasts to be used to assess and understand historical decadal prediction skill, as a basis for improvements in all aspects of end-to-end decadal prediction, and as a basis for forecasting on annual to decadal timescales. Component B undertakes ongoing production, analysis and dissemination of experimental quasi-real-time multi-model forecasts as a basis for potential operational forecast production. Component C involves the organization and coordination of case studies of particular climate shifts and variations, both natural and naturally forced (e.g. the "hiatus", volcanoes), including the study of the mechanisms that determine these behaviours. Groups are invited to participate in as many or as few of the components of the DCPP, each of which are separately prioritized, as are of interest to them.The Decadal Climate Prediction Project addresses a range of scientific issues involving the ability of the climate system to be predicted on annual to decadal timescales, the skill that is currently and potentially available, the mechanisms involved in long timescale variability, and the production of forecasts of benefit to both science and society

Interface carbon defects at 4H-SiC(0001)/SiO2 interfaces studied by electron-spin-resonance spectroscopy

We study an electron-spin-resonance (ESR) signal of carbon dangling-bond defects at 4H-SiC(0001)/SiO2 interfaces, which we call an “interface carbon defect.” The ESR signal is close to a c-axial type of the PbC centers (interfacial carbon dangling bonds) that have originally been found in porous-SiC/SiO2 interfaces. The interface carbon defects were always formed with an areal density of 3–4 × 1012 cm−2 after the standard dry oxidation of 4H-SiC(0001) surfaces. They act as electron traps and decrease the amount of free electrons in the channel region, consequently reducing the field-effect mobility of Si-face 4H-SiC MOSFETs. They were eliminated by optimum post-oxidation anneals (POAs) in either NO or POCl3 environment. Furthermore, POCl3 POAs at 1000 °C introduced a high density (1.7 × 1012 cm−2) of phosphorus donors into the channel region, increasing the free-carrier density as compared with the case of NO POAs.This work was supported by the Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), and “Next-generation power electronics” (funding agency: NEDO). This work was also partly supported by a Grant-in-Aid (Grant No. 17H02781) from the Ministry of Education, Culture, Sports, Science and Technology of Japan

Mountain torques and atmospheric oscillations

Theoretical work and general circulation model (GCM) experiments suggest that the midlatitude jet stream's interaction with large‐scale topography can drive intraseasonal oscillations in large‐scale atmospheric circulation patterns. In support of this theory, we present new observational evidence that mountain‐induced torques play a key role in 15–30‐day oscillations of the Northern Hemisphere circulation's dominant patterns. The affected patterns include the Arctic Oscillation (AO) and the Pacific‐North‐American (PNA) pattern. Positive torques both accelerate and anticipate the midlatitude westerly winds at these periodicities. Moreover, torque anomalies anticipate the onsets of weather regimes over the Pacific, as well as the break‐ups of hemispheric‐scale regimes

The Shocking Properties of Supersonic Flows: Dependence of the Thermal Overstability on M, alpha, and T_c/T_0

We investigate the Mach number dependence of the radiative overstability of shocks. We find that the stability of radiative shocks increases with decreasing Mach number, with the result that M=2 shocks require cooling exponents < -1.2 to be overstable. The frequency of oscillation of the fundamental mode has a strong Mach number dependence. We find that feedback between the cooling region and the cold dense layer (CDL) further downstream is a function of Mach number, with stronger feedback and oscillation of the boundary between the CDL and the cooling region occuring at lower Mach numbers. This feedback can be quantified in terms of the reflection coefficient of sound waves. An interesting finding is that the stability properties of low Mach number shocks can be dramatically altered if the shocked gas is able to cool to temperatures less than the pre-shock value, and it is probable that low Mach number astrophysical shocks will be overstable in a variety of situations. The results of this work are relevant to astrophysical shocks with low Mach numbers, such as supernova remnants (SNRs) immersed in a hot interstellar medium (e.g., within a starburst region), and shocks in molecular clouds, where time-dependent chemistry can lead to overstability. (Abridged)Comment: 12 pages, 12 figures, accepted by A&

Language vs individuals in cross-linguistic corpus typology

Published as a special publication of Language Documentation & Conservation (No. 25).Peer reviewe

Disinhibitory involvement of the anterior cingulate cortex in the descending antinociceptive effect induced by electroacupuncture simulation in rats

The present study was conducted to clarify the role of the anterior cingulate cortex(ACCX) in acupuncture analgesia. Experiments were performed on 35 female Wistar albino rats weighing about 300 g. Single unit recordings were made from ACCXneurons with a tungsten microelectrode. Descending ACCX neurons were identified byantidromic activation from electrical shocks applied to the ventral part of the ipsilateral PAG through a concentric needle electrode. Cathodal electroacupuncture stimulation of Ho-Ku (0.1 ms in duration, 45 Hz) for 15 min was done by inserting stainless steel needles bilaterally. An anodal silver-plate electrode (30 mm x 30 mm) was placed on the center of the abdomen. Naloxone (1.0 mg/kg, i.v.) was used to test whether changes of ACCX activities were induced by the endogenous opioid system or not. Data were collected from a total of 73 ACCX neurons. Forty-seven neurons had descending projection to the PAG, and 26 had no projections to the PAG. A majority of descending ACCX neurons were inhibited by electroacupuncture stimulation. By contrast, non-projection ACCX neurons were mainly unaffected by electroacupuncture. Naloxone did not reverse acupuncture effects on the changes of ACCX neuronal activities. Acupuncture stimulation had predominantly inhibitory effects on the activities of descending ACCX neurons. Since the functional connection between ACCX and 3/21 PAG is inhibitory, electroacupuncture caused disinhibition of PAG neurons, whose activity is closely related to descending antinociception to the spinal cord. Thisdisinhibitory effect elicited by acupuncture stimulation is thought to play a significant role in acupuncture analgesia

Correction: Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and Condition

Correction: Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and ConditionPostprint4,411