bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved aerostructural performance via aeroservoelastic tailoring of a composite wing
Authors: Krupa Eduardo P. , Cooper Jonathan E. , Pirrera Alberto , Nangia Raj 
Published: June 2018

ABSTRACTThis paper investigates the synergies and trade-offs between passive aeroelastic tailoring and adaptive aeroelastic deformation of a transport composite wing for fuel burn minimisation. This goal is achieved by optimising thickness and stiffness distributions of constitutive laminates, jig-twist shape and distributed control surface deflections through different segments of a nominal “cruise-climb” mission. Enhanced aerostructural efficiency is sought both passively and adaptively as a means of aerodynamic load redistribution, which, in turn, is used for manoeuvre load relief and minimum drag dissipation. Passive shape adaptation is obtained by embedding shear-extension and bend-twist couplings in the laminated wing skins. Adaptive camber changes are provided via full-span trailing-edge flaps. Optimised design solutions are found using a bi-level approach that integrates gradient-based and particle swarm optimisations in order to tailor structural properties at rib-bay level and retrieve blended stacking sequences. Performance benefits from the combination of passive aeroelastic tailoring with adaptive control devices are benchmarked in terms of fuel burn and a payload-range efficiency. It is shown that the aeroservoelastically tailored composite design allows for significant weight and fuel burn improvements when compared to a similar all-metallic wing. Additionally, the trailing-edge flap augmentation can extend the aircraft performance envelope and improve the overall cruise span efficiency to nearly optimal lift distributions.
On Immanent Critique in Hegel’s Phenomenology
Authors: Becker Michael A. 
Published: June 2018

AbstractI begin by identifying an ambiguity in the post-Hegelian literature on Immanent Critique, distinguishing two possible definitions: (a) judging an object against its ‘internal’ norms; and (b) accounting for one’s own standpoint with reference to the object. I then claim that both definitions are represented in Hegel’s Phenomenology, and develop extended interpretations of material from the Introduction in order to clarify and substantiate this thesis. This yields revisionist readings of the famous ‘internal criteria’ and ‘self examination’ tropes. My discussion builds towards elucidating the relation between the two definitions of Immanent Critique I have distinguished, as it is developed in the Phenomenology.
LIFTINGN-DIMENSIONAL GALOIS REPRESENTATIONS TO CHARACTERISTIC ZERO
Authors: MANOHARMAYUM JAYANTA 
Published: June 2018

AbstractLetFbe a number field, letN≥ 3 be an integer, and letkbe a finite field of characteristic ℓ. We show that ifρ:GF→GLN(k) is a continuous representation with image ofρcontainingSLN(k) then, under moderate conditions at primes dividing ℓ∞, there is a continuous representation ρ:GF→GLN(W(k)) unramified outside finitely many primes withρ~ρ mod ℓ. Stronger results are presented forρ:Gℚ→GL3(k).
The Natural Laws of Good Manners: Hobbes, Glory, and Early Modern Civility
Authors: Mark Clifton 
Published: June 2018

AbstractAccording to Hobbes, glory causes conflict in two ways: by causing competition over comparative recognition, and by making men violently sensitive to insult. Interpreters have generally depicted the sensitivity to insult as a manifestation of the desire for comparative recognition. This reading raises two problems. First, the two ways in which Hobbes uses glory are inconsistent. Second, if the problem with glory is comparison, then the law of nature enjoining the acknowledgment of equality should lead to war rather than peace. This paper illuminates these obscurities by placing Hobbes in the context of the contemporary literature on honor and civility. These sources reveal two concepts of honor which correspond to the two ways in which Hobbes writes about glory. Hobbes draws heavily from these sources, but intentionally elides the two concepts of honor in order to undermine an ideology of honor that was used to justify disobedience and unlawful violence.
A plan of capital injections based on the claims frequency
Authors: Xu Ran , Woo Jae-Kyung , Han Xixuan , Yang Hailiang 
Published: June 2018

AbstractIn this work, we propose a capital injection strategy which is periodically implemented based on the number of claims in the classical Poisson risk model. Especially, capital injection decisions are made at a predetermined accumulated number of claim instants, if the surplus is lower than a minimum required level. There appears to be a similar problem found in reliability theory such that preventive maintenance policies are performed at certain shock numbers. Assuming a combination of exponentials for the claim severities, we first derive an explicit expression for the discounted density of the surplus level after a certain number of claims if ruin has not yet occurred. Utilising this result, we study the expected total discounted capital injection until the first ruin time. To solve the differential equation associated with this quantity, we analyse an extended Lundberg’s fundamental equation. Similarly, an expression for the Laplace transform of the time to ruin is also explicitly found. Finally, we illustrate the applicability of the present capital injection strategy and methodologies through various numerical examples. In particular, for exponential claim severities, some optimal capital injection strategy which minimises the expected capital spending per unit time is numerically studied.
Using Multibeam Backscatter Data to Investigate Sediment‐Acoustic Relationships
Authors: Huang Zhi , Siwabessy Justy , Cheng Heqin , Nichol Scott 
Published: June 2018

AbstractSediment properties are known to influence acoustic backscatter intensity. This sediment‐acoustic relationship has been investigated previously through using physical geoacoustic models and empirical methods and found to be complex and nonlinear. Here we employ a robust machine‐learning statistical model (random forest decision tree) to investigate the most likely nonlinear sediment‐backscatter relationships. The analysis uses colocated sediment and acoustic backscatter data (collected from a 300‐kHz multibeam sonar system) for 564 locations in four different areas on the Australian margin. Seven sediment grain size properties (%gravel, %sand, %mud, mean grain size, sorting, skewness, and kurtosis) were used to predict the acoustic backscatter responses at individual incidence angles. The modeling results demonstrate the effectiveness of this multivariate predictive approach for the investigation of sediment‐acoustic relationship. Thus, we find that for incidence angles between 1° and 41°, the sediment variables explain around 70% of variance in the backscatter intensity. Sediment mud content was found to be the most important sediment variable in the model and has a significant negative relationship with backscatter intensity. Mean grain size was the second ranked sediment variable and found to have a positive relationship with backscatter intensity. The results also show that sediment mud content plays a key role in sorting‐backscatter and sand‐backscatter relationships. Using only two sediment properties, mud content and mean grain size, together it was possible to largely explain the sediment‐acoustic relationship. The strongest backscatter return occurred with medium sediment mud content and large mean grain sizes (or muddy coarse sand).
Effects of Wind Direction on Variations in Friction Velocity With Wind Speed Under Conditions of Strong Onshore Wind
Authors: Fang Pingzhi , Zhao Bingke , Zeng Zhihua , Yu Hui , Lei Xiaotu , Tan Jianguo 
Published: June 2018

AbstractThe effects of wind direction on variations in friction velocity with wind speed are studied under moderate (≥9 m/s) to strong (≥22 m/s) onshore wind conditions using 20‐Hz ultrasonic wind data from a coastal tower at three different heights. The effects of different averaging time intervals of 20, 10, 2, and 1 min on the variations are also investigated. Three typhoons passed by the tower during the 150 hr of observations. Regardless of wind direction, friction velocity increases with increasing wind speed, and linear regression shows that the rate of increase is ~50% less than previously reported. However, a leveling‐off or decrease in friction velocity with increasing wind speed is found under strong wind conditions using a bin‐averaged method. Wind direction affects the variations in friction velocity with wind speed. Friction velocity increases with increasing wind speed at a similar growth rate to that of previously published results, with a leveling‐off or decrease at wind speeds higher than 22 m/s when the wind blows roughly normal to the shoreline. Form drag induced by sea waves with longer wavelengths is suggested to be responsible for the effects of wind direction on the variations in friction velocity with wind speed. An averaging time interval of 1 min yields representative variations in friction velocity with wind speed using the observations described in this study.
On the Forward Modeling of Radar Doppler Spectrum Width From LES: Implications for Model Evaluation
Authors: Chen Y.‐S. , Verlinde J. , Clothiaux E. E. , Ackerman A. S. , Fridlind A. M. , Chamecki M. , Kollias P. , Kirkpatrick M. P. , Chen B.‐C. , Yu G. , Avramov A. 
Published: June 2018

AbstractLarge‐eddy simulations of an observed single‐layer Arctic mixed‐phase cloud are analyzed to study the value of forward modeling of profiling millimeter wave cloud radar Doppler spectral width for model evaluation. Individual broadening terms and their uncertainties are quantified for the observed spectral width and compared to modeled broadening terms. Modeled turbulent broadening is narrower than the observed values when the turbulent kinetic energy dissipation rate from the subgrid scale model is used in the forward model. The total dissipation rates, estimated with the subgrid scale dissipation rates and the numerical dissipation rates, agree much better with both the retrieved dissipation rates and those inferred from the power spectra of the simulated vertical air velocity. The comparison of the microphysical broadening provides another evaluative measure of the ice properties in the simulation. To accurately retrieve dissipation rates as well as each broadening term from the observations, we suggest a few modifications to previously presented techniques. First, we show that the inertial subrange spectrum filtered with the radar sampling volume is a better underlying model than the unfiltered −5/3 law for the retrieval of the dissipation rate from the power spectra of the mean Doppler velocity. Second, we demonstrate that it is important to filter out turbulence and remove the layer‐mean reflectivity‐weighted mean fall speed from the observed mean Doppler velocity to avoid overestimation of shear broadening. Finally, we provide a method to quantify the uncertainty in the retrieved dissipation rates, which eventually propagates to the uncertainty in the microphysical broadening.
Anomalous Glacier Changes in the Southeast of Tuomuer‐Khan Tengri Mountain Ranges, Central Tianshan
Authors: Li Zhi‐wei , Li Jia , Ding Xiao‐li , Wu Li‐xin , Ke Ling‐hong , Hu Jun , Xu Bing , Peng Fen 
Published: June 2018

AbstractCentral Tianshan (CTS) plays a prominent role in maintaining the vulnerable ecosystem in Central Asia. Rivers originating from it have high proportions of the runoffs contributed by glacier meltwater. In this study, the glacier mass balance in the catchments of Muzart and Karayulun rivers, CTS, was estimated by a geodetic method based on Advanced Land Observing Satellite/Panchromatic Remote‐sensing Instrument for Stereo Mapping images and Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM). The results revealed that at the west and east glacial centers in the study area, the 2000–2011 mass loss rates were −0.03 ± 0.17 and −0.06 ± 0.17 m w.e./a, respectively, considerably lower than other CTS zones. In order to ascertain this stable glacier state, we also performed a geodetic measurement based on TerraSAR‐X add‐on for Digital Elevation Measurement (TanDEM‐X) images and SRTM DEM (2000–2012), and the results are similar (0.01 ± 0.17 and −0.04 ± 0.17 m w.e./a, respectively). The glacier thickness change around the regional snowline was close to zero. The strong capability of cold storage and the temperature drop in the early 21st century may account for the anomalous mass changes. Despite slight overall mass changes, obvious thinning was observed on many exposed glacier feet. This study indicates that the glacier melting can be effectively controlled if the rising trend of temperatures is reversed; furthermore, the land surface hydrological model should be calibrated with geodetic glacier mass balance measurement when it is used to simulate the streamflow trend in the headwater basin.
Secondary Organic Aerosol Formation From Isoprene Epoxides in the Pearl River Delta, South China: IEPOX‐ and HMML‐Derived Tracers
Authors: He Quan‐Fu , Ding Xiang , Fu Xiao‐Xin , Zhang Yu‐Qing , Wang Jun‐Qi , Liu Ye‐Xin , Tang Ming‐Jin , Wang Xin‐Ming , Rudich Yinon 
Published: June 2018

AbstractAtmospheric photooxidation of isoprene forms isoprene epoxydiols (IEPOX) and hydroxymethel‐methyl‐α‐lactone (HMML) via hydroperoxyl radical (HO2) channel and NO/NO2 channel, respectively. Reactive uptake of these epoxides onto particles produces isoprene secondary organic aerosols (iSOA). Currently, there is little information regarding these two epoxides during iSOA formation in polluted regions. In this study, iSOA tracers from IEPOX and HMML were measured from summer to fall in the heavily polluted Pearl River Delta (PRD) region. The total concentration of the iSOA tracers ranged from 5.77 to 466 ng m−3. Isoprene SOA tracers correlated well with sulfate (p < 0.01), indicating that the abundant sulfate in the PRD plays an important role in iSOA formation. A kinetic model of IEPOX loss showed that 58% of IEPOX could undergo ring‐opening reactions under the polluted PRD conditions in summer. This leads to high levels of IEPOX‐derived SOA tracers in the PRD. High temperature in the PRD (>22 °C) suppresses the production of HMML, likely as a result of fast decomposition of HMML's precursor under high temperatures. Thus, the HMML‐derived tracers had lower levels than the IEPOX‐derived SOA tracers during the whole campaign. The ratios of the IEPOX‐derived tracers to the HMML‐derived SOA tracers in summer were ~3 times higher than those in fall. This seasonal trend may be explained by the relative high isoprene/NOx ratio, temperature, and fast heterogeneous reaction of IEPOX in summer. Our study shows that in highly polluted regions like PRD, reduction in SO2 emission can significantly reduce iSOA formation.
Influence of Stream‐Subsurface Exchange Flux and Bacterial Biofilms on Oxygen Consumption Under Nutrient‐Rich Conditions
Authors: De Falco N. , Boano F. , Bogler A. , Bar‐Zeev E. , Arnon S. 
Published: June 2018

AbstractThe lack of a complete understanding of the complex reciprocal interactions between hydrological processes and the structure and function of microbial communities limits our ability to improve the predictions of microbial metabolism in streams. We report here on how overlying water velocity and losing and gaining flux interact with bacterial community structure and its activity to control oxygen consumption in a sandy streambed under high nutrient levels. We used an experimental flume packed with natural sediment and measured the bacterial biomass distribution and oxygen profiles in the streambed and across bed forms. Local oxygen consumption rates were calculated with a 1‐D numerical model (GRADIENT). Bacterial abundance and production rates varied across the bed form within 1 order of magnitude, while their taxonomic classes were similar across bed forms despite variations in flow conditions and sediment disturbance events. However, bacterial production rates were not directly correlated with bacterial abundance. On the other hand, oxygen consumption rates ranged over 4 orders of magnitude across the bed forms and were highly correlated with the vertical exchange flux between the water and the streambed. The results strongly suggest that under high nutrient levels, the system is, in general, transport limited and that predicting oxygen consumption rates depends on local vertical exchange fluxes.
Monte Carlo Simulations of the Interaction of Fast Proton and Hydrogen Atoms With the Martian Atmosphere and Comparison With In Situ Measurements
Authors: Bisikalo D. V. , Shematovich V. I. , Gérard J.‐C. , Hubert B. 
Published: June 2018

AbstractWe present model results of the interaction of proton and hydrogen atom precipitation with the Martian atmosphere. We use a kinetic Monte Carlo model developed earlier for the analysis of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA‐3) Mars Express data. With the availability of Mars Atmosphere and Volatile Evolution Mission in situ measurements, not only the flux of protons incident on the atmosphere but also their degradation along the orbit may now be described. The comparison of the simulations with data collected with the Solar Wind Ion Analyzer shows that the Monte Carlo model reproduces some of the measured features. The results of comparison between simulations and measurements of the proton fluxes at low altitudes make it possible to infer the efficiency of charge exchange between solar wind and the extended hydrogen corona if the value of the magnetic field is measured simultaneously. We also find that the induced magnetic field plays a very important role in the formation of the backscattered flux and strongly controls its magnitude. At the same time, discrepancies between the modeled and the measured energy spectra of the backscattered protons are pointed out. We suggest that some of the physical processes controlling the upward flux are not fully understood or that the data processing of the measured backscattered proton flux should be improved.
Modeled Gravity Wave‐Like Perturbations in the Brightness of Far Ultraviolet Emissions for the GOLD Mission
Authors: Greer K. R. , England S. L. , Becker E. , Rusch D. , Eastes R. 
Published: June 2018

AbstractThe NASA Global‐scale Observations of Limb and Disk (GOLD) mission will study the coupling of the thermosphere with the lower atmosphere through an examination of temperature and composition, allowing the study of atmospheric waves. A key mechanism of energy and momentum transport between atmospheric regions is gravity waves. GOLD is an imaging spectrograph that will measure Earth's airglow emissions (both nightglow and dayglow) in the far ultraviolet range from 132 to 162 nm, including the atomic oxygen doublet at 135.6 nm and molecular nitrogen Lyman‐Birge‐Hopfield bands. GOLD will be the first instrument to make such measurements from the perspective of a geostationary orbit, which creates unique challenges and opportunities for observing atmospheric waves. Here we model the ability of the GOLD imager to detect a gravity wave‐like perturbation from the emergent brightness variations using a combination of a general circulation model and a model of the thermospheric airglow in the far ultraviolet. A 10% perturbation in temperature (±59 K at 150 km) and constituent densities is introduced into the vertical columns of the atmosphere, which results in a ±1.5 Rayleigh perturbation to the brightness of both spectral features, with the same wave period as the introduced perturbation. For the expected total signal, particle background counts, and chosen spectral feature, signal‐to‐noise calculations indicate that integration for several minutes will allow gravity wave perturbations to be observed in brightness perturbations on a single pixel of an image.
Response of Different Ion Species to Local Magnetic Dipolarization Inside Geosynchronous Orbit
Authors: Motoba T. , Ohtani S. , Gkioulidou M. , Ukhorskiy A. Y. , Mitchell D. G. , Takahashi K. , Lanzerotti L. J. , Kletzing C. A. , Spence H. E. , Wygant J. R. 
Published: June 2018

AbstractThis paper examines how hydrogen, helium, and oxygen (H, He, and O) ion fluxes at 1–1,000 keV typically respond to local magnetic dipolarization inside geosynchronous orbit. We extracted 144 dipolarizations that occurred at magnetic inclination >30° from the 2012–2016 tail seasons' observations of the Van Allen Probes spacecraft and then defined typical flux changes of these ion species by performing a superposed epoch analysis. On average, the dipolarization inside geosynchronous orbit is accompanied by a precursory transient decrease in the northward magnetic field component, transient impulsive enhancement in the westward electric field component, and decrease (increase) in the proton density (temperature). The coincident ion species experience an energy‐dependent flux change, consisting of enhancement (depression) at energies above (below) ~50 keV. These properties morphologically resemble those around dipolarization fronts (or fast flows) in the near‐Earth tail. A distinction among the ion species is the average energy of the flux ratio peak, being at 200–400 keV (100–200 keV) for He (H and O) ions. The flux ratio peaks at different energies likely reflect the different charge states of injected ionospheric and/or solar wind origin ion species. The ion spectra become harder for sharp dipolarizations, suggesting the importance of accompanying electric field in transporting and/or energizing the ions efficiently. Interestingly, the average flux ratio peak does not differ significantly among the ion species for ~2 min after onset, which implies that mass‐dependent acceleration process is less important in the initial stage of dipolarization.
Closed‐Form Expressions of Seismic Deformation in a Homogeneous Maxwell Earth Model
Authors: Tang He , Sun Wenke 
Published: June 2018

AbstractEarthquake activities involve coseismic and postseismic deformations, and these seismic deformations can be computed using corresponding dislocation theories. However, conventional dislocation theories are usually given using numerical dislocation Love numbers and numerical Green's functions. In this study, we present explicit expressions of the time‐dependent dislocation Love numbers for a point source in a homogeneous viscoelastic (Maxwell rheology) spherical Earth model and the displacement Green's functions. Other surface variables, such as tilt and strain, can be obtained in a similar manner. The analytical Green's functions are derived from the degenerate deformation system without considering self‐gravitation. The Green's functions can be applied to efficiently compute viscoelastic seismic and volcanic deformations in an approximate manner.