bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oil Slick Observation at Low Incidence Angles in Ku‐Band
Authors: Panfilova M. A. , Karaev V. Y. , Guo Jie 
Published: February 2018

AbstractOn the 20 April 2010 the oil platform Deep Water Horizon in the Gulf of Mexico suffered an explosion during the final phases of drilling an exploratory well. As a result, an oil film covered the sea surface area of several thousand square kilometers. In the present paper the data of the Ku‐band Precipitation Radar, which operates at low incidence angles, were used to explore the oil spill event. The two‐scale model of the scattering surface was used to describe radar backscatter from the sea surface. The algorithm for retrieval of normalized radar cross section at nadir and the total slope variance of large‐scale waves compared to the wavelength of electromagnetic wave (22 mm) was developed for the Precipitation Radar swath. It is shown that measurements at low incidence angles can be used for oil spill detection. This is the first time that the dependence of mean square slope of large‐scale waves on wind speed has been obtained for oil slicks from Ku‐band data, and compared to mean square slope obtained by Cox and Munk from optical data.
Strip‐Bark Morphology and Radial Growth Trends in Ancient Pinus sibirica Trees From Central Mongolia
Authors: Leland Caroline , Cook Edward R. , Andreu‐Hayles Laia , Pederson Neil , Hessl Amy , Anchukaitis Kevin J. , Byambasuren Oyunsanaa , Nachin Baatarbileg , Davi Nicole , D'Arrigo Rosanne , Griffin Kevin , Bishop Daniel A. , Rao Mukund Palat 
Published: February 2018

AbstractSome of the oldest and most important trees used for dendroclimatic reconstructions develop strip‐bark morphology, in which only a portion of the stem contains living tissue. Yet the ecophysiological factors initiating strip bark and the potential effect of cambial dieback on annual ring widths and tree‐ring estimates of past climate remain poorly understood. Using a combination of field observations and tree‐ring data, we investigate the causes and timing of cambial dieback events in Pinus sibirica strip‐bark trees from central Mongolia and compare the radial growth rates and trends of strip‐bark and whole‐bark trees over the past 515 years. Results indicate that strip bark is more common on the southern aspect of trees, and dieback events were most prevalent in the 19th century, a cold and dry period. Further, strip‐bark and whole‐bark trees have differing centennial trends, with strip‐bark trees exhibiting notably large increases in ring widths at the beginning of the 20th century. We find a steeper positive trend in the strip‐bark chronology relative to the whole‐bark chronology when standardizing with age‐dependent splines. We hypothesize that localized warming on the southern side of stems due to solar irradiance results in physiological damage and dieback and leads to increasing tree‐ring increment along the living portion of strip‐bark trees. Because the impact of cambial dieback on ring widths likely varies depending on species and site, we suggest conducting a comparison of strip‐bark and whole‐bark ring widths before statistically treating ring‐width data for climate reconstructions.
Time‐Variable Transit Time Distributions in the Hyporheic Zone of a Headwater Mountain Stream
Authors: Ward Adam S. , Schmadel Noah M. , Wondzell Steven M. 
Published: February 2018

AbstractExchange of water between streams and their hyporheic zones is known to be dynamic in response to hydrologic forcing, variable in space, and to exist in a framework with nested flow cells. The expected result of heterogeneous geomorphic setting, hydrologic forcing, and between‐feature interaction is hyporheic transit times that are highly variable in both space and time. Transit time distributions (TTDs) are important as they reflect the potential for hyporheic processes to impact biogeochemical transformations and ecosystems. In this study we simulate time‐variable transit time distributions based on dynamic vertical exchange in a headwater mountain stream with observed, heterogeneous step‐pool morphology. Our simulations include hyporheic exchange over a 600 m river corridor reach driven by continuously observed, time‐variable hydrologic conditions for more than 1 year. We found that spatial variability at an instance in time is typically larger than temporal variation for the reach. Furthermore, we found reach‐scale TTDs were marginally variable under all but the most extreme hydrologic conditions, indicating that TTDs are highly transferable in time. Finally, we found that aggregation of annual variation in space and time into a “master TTD” reasonably represents most of the hydrologic dynamics simulated, suggesting that this aggregation approach may provide a relevant basis for scaling from features or short reaches to entire networks.
Turbulent Kinetic Energy in Submerged Model Canopies Under Oscillatory Flow
Authors: Zhang Yinghao , Tang Caihong , Nepf Heidi 
Published: February 2018

AbstractLaboratory experiments measured the velocity inside a model meadow of submerged, flexible vegetation under 1 and 2 s period waves. The model plant consisted of a rigid stem and strap‐like blades, similar to the seagrass Zostera marina and the freshwater eelgrass Vallisneria Americana. The ratio of wave excursion (Aw) to stem spacing (S) determined whether, or not, plant‐generated turbulence enhanced the turbulence level within the meadow, compared to bare bed. Specifically, near‐bed turbulence was enhanced for conditions with Aw/S > 0.5, and for these conditions the turbulence (TKE) normalized by the RMS wave velocity squared, TKE/Uw,RMS2, increased monotonically with the plant solid volume fraction, ϕ. The plant‐generated turbulence was greater in the stem region than in the blade region, and this was attributed to the greater relative motion between the waves and rigid stem, compared to the flexible blades. A model previously developed to predict TKE in unidirectional flow through a rigid emergent canopy was modified by replacing the time‐mean current with the RMS wave velocity. With a fitted scale coefficient, the modified model predicts TKE as a function of RMS wave velocity in the meadow, stem and blade geometry, and solid volume fraction. Wave decay was also measured and shown to have a linear correlation with the measured TKE within the canopy, providing a second method to predict meadow TKE in the field.
Assessment of CO2 Storage Potential in Naturally Fractured Reservoirs With Dual‐Porosity Models
Authors: March Rafael , Doster Florian , Geiger Sebastian 
Published: February 2018

AbstractNaturally Fractured Reservoirs (NFR's) have received little attention as potential CO2 storage sites. Two main facts deter from storage projects in fractured reservoirs: (1) CO2 tends to be nonwetting in target formations and capillary forces will keep CO2 in the fractures, which typically have low pore volume; and (2) the high conductivity of the fractures may lead to increased spatial spreading of the CO2 plume. Numerical simulations are a powerful tool to understand the physics behind brine‐CO2 flow in NFR's. Dual‐porosity models are typically used to simulate multiphase flow in fractured formations. However, existing dual‐porosity models are based on crude approximations of the matrix‐fracture fluid transfer processes and often fail to capture the dynamics of fluid exchange accurately. Therefore, more accurate transfer functions are needed in order to evaluate the CO2 transfer to the matrix. This work presents an assessment of CO2 storage potential in NFR's using dual‐porosity models. We investigate the impact of a system of fractures on storage in a saline aquifer, by analyzing the time scales of brine drainage by CO2 in the matrix blocks and the maximum CO2 that can be stored in the rock matrix. A new model to estimate drainage time scales is developed and used in a transfer function for dual‐porosity simulations. We then analyze how injection rates should be limited in order to avoid early spill of CO2 (lost control of the plume) on a conceptual anticline model. Numerical simulations on the anticline show that naturally fractured reservoirs may be used to store CO2.
The State of U.S. Urban Water: Data and the Energy‐Water Nexus
Authors: Chini Christopher M. , Stillwell Ashlynn S. 
Published: February 2018

AbstractData on urban water resources are scarce, despite a majority of the U.S. population residing in urban environments. Further, information on the energy required to facilitate the treatment, distribution, and collection of urban water are even more limited. In this study, we evaluate the energy‐for‐water component of the energy‐water nexus by providing and analyzing a unique primary database consisting of drinking water and wastewater utility flows and energy. These anthropogenic fluxes of water through the urban environment are used to assess the state of the U.S. urban energy‐water nexus at over 160 utilities. The average daily per person water flux is estimated at 560 L of drinking water and 500 L of wastewater. Drinking water and wastewater utilities require 340 kWh/1,000 m3 and 430 kWh/1,000 m3 of energy, respectively, to treat these resources. The total national energy demand for water utilities accounts for 1.0% of the total annual electricity consumption of the United States. Additionally, the water and embedded energy loss associated with non‐revenue water accounts for 9.1 × 109 m3 of water and 3,100 GWh, enough electricity to power 300,000 U.S. households annually. Finally, the water flux and embedded energy fluctuated monthly in many cities. As the nation's water resources become increasingly scarce and unpredictable, it is essential to have a set of empirical data for continuous evaluation and updates on the state of the U.S. urban energy‐water nexus.
Fabrication of Nickel–Cobalt Bimetal Phosphide Nanocages for Enhanced Oxygen Evolution Catalysis
Authors: Qiu Bocheng , Cai Lejuan , Wang Yang , Lin Ziyuan , Zuo Yunpeng , Wang Mengye , Chai Yang 
Published: February 2018

AbstractReplacement of precious metals with earth‐abundant electrocatalysts for oxygen evolution reaction (OER) holds great promise for realizing practically viable water‐splitting systems. It still remains a great challenge to develop low‐cost, highly efficient, and durable OER catalysts. Here, the composition and morphology of Ni–Co bimetal phosphide nanocages are engineered for a highly efficient and durable OER electrocatalyst. The nanocage structure enlarges the effective specific area and facilitates the contact between catalyst and electrolyte. The as‐prepared Ni–Co bimetal phosphide nanocages show superior OER performance compared with Ni2P and CoP nanocages. By controlling the molar ratio of Ni/Co atoms in Ni–Co bimetal hydroxides, the Ni0.6Co1.4P nanocages derived from Ni0.6Co1.4(OH)2 nanocages exhibit remarkable OER catalytic activity (η = 300 mV at 10 mA cm−2) and long‐term stability (10 h for continuous test). The density‐functional‐theory calculations suggest that the appropriate Co doping concentration increases density of states at the Fermi level and makes the d‐states more close to Fermi level, giving rise to high charge carrier density and low intermedia adsorption energy than those of Ni2P and CoP. This work also provides a general approach to optimize the catalysis performance of bimetal compounds.
Redox‐Stability of Alkoxy‐BDT Copolymers and their Use for Organic Bioelectronic Devices
Authors: Giovannitti Alexander , Thorley Karl J. , Nielsen Christian B. , Li Jun , Donahue Mary J. , Malliaras George G. , Rivnay Jonathan , McCulloch Iain 
Published: February 2018

AbstractOrganic semiconductors can be employed as the active layer in accumulation mode organic electrochemical transistors (OECTs), where redox stability in aqueous electrolytes is important for long‐term recordings of biological events. It is observed that alkoxy‐benzo[1,2‐b:4,5‐b′]dithiophene (BDT) copolymers can be extremely unstable when they are oxidized in aqueous solutions. The redox stability of these copolymers can be improved by molecular design of the copolymer where it is observed that the electron rich comonomer 3,3′‐dimethoxy‐2,2′‐bithiophene (MeOT2) lowers the oxidation potential and also stabilizes positive charges through delocalization and resonance effects. For copolymers where the comonomers do not have the same ability to stabilize positive charges, irreversible redox reactions are observed with the formation of quinone structures, being detrimental to performance of the materials in OECTs. Charge distribution along the copolymer from density functional theory calculations is seen to be an important factor in the stability of the charged copolymer. As a result of the stabilizing effect of the comonomer, a highly stable OECT performance is observed with transconductances in the mS range. The analysis of the decomposition pathway also raises questions about the general stability of the alkoxy‐BDT unit, which is heavily used in donor–acceptor copolymers in the field of photovoltaics.
Elemental Ferroelectricity and Antiferroelectricity in Group‐V Monolayer
Authors: Xiao Chengcheng , Wang Fang , Yang Shengyuan A. , Lu Yunhao , Feng Yuanping , Zhang Shengbai 
Published: February 2018

AbstractFerroelectricity is usually found in compound materials composed by different elements. Here, based on first‐principles calculations, spontaneous electric polarization and ferroelectricity in 2D elemental group‐V (As, Sb, and Bi) monolayer with the puckered lattice structure similar to phosphorene is revealed. These are the first example of elemental ferroelectric materials. The polarization is due to the spontaneous lattice distortion with atomic layer buckling and has quite sizable values, comparable or even larger than that recently found in 2D monolayer compound SnTe. Interestingly, for Bi monolayer, apart from the ferroelectric phase, it is found that it can also host an antiferroelectric phase. The Curie temperatures of these elemental materials can be higher than room temperature, making them promising for realizing ultrathin ferroelectric devices of broad interest. A general model is constructed to understand and search for 2D ferroelectric and antiferroelectric materials in future studies.
Transparent, Anisotropic Biofilm with Aligned Bacterial Cellulose Nanofibers
Authors: Wang Sha , Li Tian , Chen Chaoji , Kong Weiqing , Zhu Shuze , Dai Jiaqi , Diaz Alfredo J. , Hitz Emily , Solares Santiago D. , Li Teng , Hu Liangbing 
Published: February 2018

AbstractCellulose nanofibrils are attractive as building blocks for advanced photonic, optoelectronic, microfluidic, and bio‐based devices ranging from transistors and solar cells to fluidic and biocompatible injectable devices. For the first time, an ultrastrong and ultratough cellulose film, which is composed of densely packed bacterial cellulose (BC) nanofibrils with hierarchical fibril alignments, is successfully demonstrated. The molecular level alignment stems from the intrinsic parallel orientation of crystalline cellulose molecules produced by Acetobacter xylinum. These aligned long‐chain cellulose molecules form subfibrils with a diameter of 2–4 nm, which are further aligned to form nanofibril bundles. The BC film yields a record‐high tensile strength (≈1.0 GPa) and toughness (≈25 MJ m−3). Being ultrastrong and ultratough, yet the BC film is also highly flexible and can be folded into desirable shapes. The BC film exhibits a controllable manner of alignment and is highly transparent with modulated optical properties, paving the way to enabling new functionalities in mechanical, electrical, fluidic, photonics, and biocompatible applications.
Oxide Thin‐Film Electronics using All‐MXene Electrical Contacts
Authors: Wang Zhenwei , Kim Hyunho , Alshareef Husam N. 
Published: February 2018

Abstract2D MXenes have shown great promise in electrochemical and electromagnetic shielding applications. However, their potential use in electronic devices is significantly less explored. The unique combination of metallic conductivity and hydrophilic surface suggests that MXenes can also be promising in electronics and sensing applications. Here, it is shown that metallic Ti3C2 MXene with work function of 4.60 eV can make good electrical contact with both zinc oxide (ZnO) and tin monoxide (SnO) semiconductors, with negligible band offsets. Consequently, both n‐type ZnO and p‐type SnO thin‐film transistors (TFTs) have been fabricated entirely using large‐area MXene (Ti3C2) electrical contacts, including gate, source, and drain. The n‐ and p‐type TFTs show balanced performance, including field‐effect mobilities of 2.61 and 2.01 cm2 V−1 s−1 and switching ratios of 3.6 × 106 and 1.1 × 103, respectively. Further, complementary metal oxide semiconductor (CMOS) inverters are demonstrated. The CMOS inverters show large voltage gain of 80 and excellent noise margin of 3.54 V, which is 70.8% of the ideal value. Moreover, the operation of CMOS inverters is shown to be very stable under a 100 Hz square waveform input. The current results suggest that MXene (Ti3C2) can play an important role as contact material in nanoelectronics.
Bendamustine‐based conditioning prior to autologous stem cell transplantation (ASCT): Results of a French multicenter study of 474 patients from LYmphoma Study Association (LYSA) centers
Authors: Chantepie Sylvain P. , Garciaz Sylvain , Tchernonog Emmanuelle , Peyrade Frederic , Larcher Marie‐Virginie , Diouf Momar , Fornecker Luc‐Mathieu , Houot Roch , Gastinne Thomas , Soussain Carole , Malak Sandra , Lemal Richard , Delette Caroline , Ibrahim Ahmad , Gac Anne‐Claire , Reboursière Emilie , Vilque Jean‐Pierre , Bekadja Mohamed‐Amine , Casasnovas Rene‐Olivier , Gressin Remy , Guidez Stéphanie , Coso Diane , Herbaux Charles , Yakoub‐Agha Ibrahim , Bouabdallah Krimo , Durot Eric , Damaj Gandhi 
Published: February 2018

AbstractCarmustine shortage has led to an increase use of alternative conditioning regimens prior to autologous stem cell transplantation for the treatment of lymphoma, including Bendamustine‐based (BeEAM). The aim of this study was to evaluate the safety of the BeEAM regimen in a large cohort of patients. A total of 474 patients with a median age of 56 years were analyzed. The majority of patients had diffuse large B‐cell lymphoma (43.5%). Bendamustine was administered at a median dose of 197 mg/m2/day (50‐250) on days‐7 and −6. The observed grade 1‐4 toxicities included mucositis (83.5%), gastroenteritis (53%), skin toxicity (34%), colitis (29%), liver toxicity (19%), pneumonitis (5%), and cardiac rhythm disorders (4%). Nonrelapse mortality (NRM) was reported in 3.3% of patients. Acute renal failure (ARF) was reported in 132 cases (27.9%) (G ≥2; 12.3%). Organ toxicities and death were more frequent in patients with post conditioning renal failure. In a multivariate analysis, pretransplant chronic renal failure, bendamustine dose >160 mg/m2 and age were independent prognostic factors for ARF. Pretransplant chronic renal failure, hyperhydration volume, duration of hyperhydration, and etoposide dose were predictive factors of NRM. A simple, four‐point scoring system can stratify patients by levels of risk for ARF and may allow for a reduction in the bendamustine dose to avoid toxicity. Drugs shortage may have dangerous consequences. Prospective, comparative studies are needed to confirm the toxicity/efficacy extents from this conditioning regimen compared to other types of high dose therapy.
Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes
Authors: McGrath Kate , El‐Zaatari Sireen , Guatelli‐Steinberg Debbie , Stanton Margaret A. , Reid Donald J. , Stoinski Tara S. , Cranfield Michael R. , Mudakikwa Antoine , McFarlin Shannon C. 
Published: February 2018

AbstractObjectiveLinear enamel hypoplasia (LEH) is a condition marked by localized reductions in enamel thickness, resulting from growth disruptions during dental development. We use quantitative criteria to characterize the depth of LEH defects and “normal” perikymata in great apes. We test the hypothesis that mountain gorillas have shallow defects compared to other taxa, which may have led to their underestimation in previous studies.Materials and MethodsPrevious attempts to characterize LEH morphology quantitatively have been limited in sample size and scope. We generated digital elevation models using optical profilometry (Sensofar PLu Neox) and extracted 2D coordinates using ImageJ to quantify depths in canines from three great ape genera (N = 75 perikymata; 255 defects).ResultsAll defect depths fall outside the distribution of perikymata depths. Mountain gorilla defects are significantly shallower than those of other great ape taxa examined, including western lowland gorillas. Females have significantly deeper defects than males in all taxa. The deepest defect belongs to a wild‐captured zoo gorilla. Virunga mountain gorilla specimens collected by Dian Fossey exhibit deeper defects than those collected recently.DiscussionShallow defect morphology in mountain gorillas may have led to an underestimation of LEH prevalence in past studies. Defect depth is used as a proxy for insult severity, but depth might be influenced by inter‐ and intra‐specific variation in enamel growth. Future studies should test whether severe insults are associated with deeper defects, as might be the case with Haloko, a wild‐captured gorilla. Ongoing histologic studies incorporating associated behavioral records will test possible factors that underlie differences in defect morphology.
Temperature and frequency‐dependent creep and recovery studies on PVDF‐HFP/organo‐modified layered double hydroxides nanocomposites
Authors: Shojaei Leila , Goodarzi Vahabodin , Otadi Maryam , Khonakdar Hossein Ali , Jafari Seyed Hassan , Asghari Gholam hossein , Reuter Uta 
Published: February 2018

ABSTRACTA series of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) loaded with various contents of layered double hydroxides (LDHs) nanoparticles were prepared via a melt mixing method. Detailed investigations on LDH dispersion state in the polymeric matrix conducted by TEM revealed intercalated/exfoliated, and agglomerated structures at low (1 wt %) and high (>3 wt %) loadings of LDH contents, respectively. Wide angle X‐ray scattering and DSC results showed that incorporation of LDH into PVDF‐HFP matrix reduced its overall crystallinity and helped to form polar crystallites, while the crystal size at 020 crystallographic directions was found to be most affected by presence and dispersion state of LDH in the matrix. TGA results showed LDH improved thermal stability of matrix however, unlike many other nanomaterials it significantly reduced the residual mass which highlights catalytic role of LDH in degradation of residual carbon char. Detailed analysis on creep and recovery data over wide range of selected temperatures revealed that the creep compliance of nanocomposites are basically controlled by crystallinity and presence of LDH at low and high temperatures, respectively. Based on obtained storage modulus and creep compliance master curves it was also found that the influence of LDH on decreasing the creep compliance and improving viscoelastic properties of PVDF‐HFP over long time period and over high frequency ranges becomes more pronounced. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46352.