bluuebunny/crossref_metadata_2025_split huggingface dataset:
Velocity‐dependent frictional weakening of large rock avalanche basal facies: Implications for rock avalanche hypermobility?
Authors: Wang Y. F. , Dong J. J. , Cheng Q. G. 
Published: March 2017

AbstractTo characterize the hypermobility mechanism of rock avalanches, a series of rotary shear tests at different shearing velocities (Veq) ranging from 0.07 m/s to 1.31 m/s and at a normal stress of 1.47 MPa were carried out on soil sampled from the basal facies of the Yigong rock avalanche that occurred in the Tibetan plateau in China. Through conducting these tests, the macroscale and microscale features of the deformed samples were analyzed in detail with the following valuable conclusions being reached: (1) soil subjected to rotary shear exhibits a clear velocity‐dependent weakening characteristic with an apparent steady state friction of 0.13 being reached at Veq ≥ 0.61 m/s, (2) high‐temperature rises and layers with high porosity were observed in the samples sheared at Veq ≥ 0.61 m/s, and (3) the cooperation of thermal pressurization and moisture fluidization induced by friction heating plays an important role in explaining the marked frictional weakening of the soil. In addition, the appearance of nanoparticles due to particle fragmentation should facilitate the weakening of the soil but is not the key reason for the marked frictional weakening.
Rock anelasticity due to patchy saturation and fabric heterogeneity: A double double‐porosity model of wave propagation
Authors: Ba Jing , Xu Wenhao , Fu Li‐Yun , Carcione José M. , Zhang Lin 
Published: March 2017

AbstractHeterogeneity of rock's fabric can induce heterogeneous distribution of immiscible fluids in natural reservoirs, since the lithological variations (mainly permeability) may affect fluid migration in geological time scales, resulting in patchy saturation of fluids. Therefore, fabric and saturation inhomogeneities both affect wave propagation. To model the wave effects (attenuation and velocity dispersion), we introduce a double double‐porosity model, where pores saturated with two different fluids overlap with pores having dissimilar compressibilities. The governing equations are derived by using Hamilton's principle based on the potential energy, kinetic energy, and dissipation functions, and the stiffness coefficients are determined by gedanken experiments, yielding one fast P wave and four slow Biot waves. Three examples are given, namely, muddy siltstones, clean dolomites, and tight sandstones, where fabric heterogeneities at three different spatial scales are analyzed in comparison with experimental data. In muddy siltstones, where intrapore clay and intergranular pores constitute a submicroscopic double‐porosity structure, wave anelasticity mainly occurs in the frequency range (104–107 Hz), while in pure dolomites with microscopic heterogeneity of grain contacts and tight sandstones with mesoscopic heterogeneity of less consolidated sands, it occurs at 103–107 Hz and 101–103 Hz (seismic band), respectively. The predicted maximum quality factor of the fast compressional wave for the sandstone is the lowest (approximately 8), and that of the dolomite is the highest. The results of the diffusive slow waves are affected by the strong friction effects between solids and fluids. The model describes wave propagation in patchy‐saturated rocks with fabric heterogeneity at different scales, and the relevant theoretical predictions agree well with the experimental data in fully and partially saturated rocks.
Effect of capillary and viscous force on CO2 saturation and invasion pattern in the microfluidic chip
Authors: Zheng Xianglei , Mahabadi Nariman , Yun Tae Sup , Jang Jaewon 
Published: March 2017

AbstractCarbon dioxide sequestration into geological formations has been identified as an alternative to mitigate the global climate change. The CO2 invasion pattern is dependent on various factors such as fluid viscosity, interfacial tension, injection rate, and the characteristics of porous media. Among these variables, we provide a systematic experimental study on the influence of the injection rate and the phase of CO2 invading into a brine‐saturated microfluidic chip in order to quantitatively assess the displacement ratio. Interfacial tension and contact angle are accurately measured under the temperature and pressure conditions relevant to in situ conditions. The injection rate varies 3 orders of magnitude for gaseous, liquid, supercritical CO2, and CO2‐water foam invasion. The capillary number and the viscosity ratio are calculated for each experimental condition, and the displacement ratio (CO2 saturation) is obtained after CO2 invasion. The results show that the saturation of injected CO2 is controlled by manipulating the injection rate and the phase of invading fluid, which can be used to optimize the in situ storage capacity. Especially, the CO2‐water foam displaces almost all brine out of the microfluidic chip, but the increase in CO2 saturation is 23% ~ 53% compared to pure gaseous CO2 injection due to the water initially mixed in the CO2‐water foam. The potential advantages of using CO2‐water foam in the geological CO2 sequestration were also discussed.
Onset of solid‐state mantle convection and mixing during magma ocean solidification
Authors: Maurice Maxime , Tosi Nicola , Samuel Henri , Plesa Ana‐Catalina , Hüttig Christian , Breuer Doris 
Published: March 2017

AbstractThe energy sources involved in the early stages of the formation of terrestrial bodies can induce partial or even complete melting of the mantle, leading to the emergence of magma oceans. The fractional crystallization of a magma ocean can cause the formation of a compositional layering that can play a fundamental role for the subsequent long‐term dynamics of the interior and for the evolution of geochemical reservoirs. In order to assess to what extent primordial compositional heterogeneities generated by magma ocean solidification can be preserved, we investigate the solidification of a whole‐mantle Martian magma ocean, and in particular the conditions that allow solid‐state convection to start mixing the mantle before solidification is completed. To this end, we performed 2‐D numerical simulations in a cylindrical geometry. We treat the liquid magma ocean in a parameterized way while we self‐consistently solve the conservation equations of thermochemical convection in the growing solid cumulates accounting for pressure‐, temperature‐, and, where it applies, melt‐dependent viscosity. By testing the effects of different cooling rates and convective vigor, we show that for a lifetime of the liquid magma ocean of 1 Myr or longer, the onset of solid‐state convection prior to complete mantle crystallization is likely and that a significant part of the compositional heterogeneities generated by fractionation can be erased by efficient mantle mixing. We discuss the consequences of our findings in relation to the formation and evolution of compositional reservoirs on Mars and on the other terrestrial bodies of the solar system.
Comment on “Most computational hydrology is not reproducible, so is it really science?” by Christopher Hutton et al.
Authors: Añel Juan A. 
Published: March 2017

AbstractNowadays, the majority of the scientific community is not aware of the risks and problems associated with an inadequate use of computer systems for research, mostly for reproducibility of scientific results. Such reproducibility can be compromised by the lack of clear standards and insufficient methodological description of the computational details involved in an experiment. In addition, the inappropriate application or ignorance of copyright laws can have undesirable effects on access to aspects of great importance of the design of experiments and therefore to the interpretation of results.
Tuning the Solid Electrolyte Interphase for Selective Li‐ and Na‐Ion Storage in Hard Carbon
Authors: Soto Fernando A. , Yan Pengfei , Engelhard Mark H. , Marzouk Asma , Wang Chongmin , Xu Guiliang , Chen Zonghai , Amine Khalil , Liu Jun , Sprenkle Vincent L. , El‐Mellouhi Fedwa , Balbuena Perla B. , Li Xiaolin 
Published: March 2017

Solid‐electrolyte interphase (SEI) films with controllable properties are highly desirable for improving battery performance. In this paper, a combined experimental and theoretical approach is used to study SEI films formed on hard carbon in Li‐ and Na‐ion batteries. It is shown that a stable SEI layer can be designed by precycling an electrode in a desired Li‐ or Na‐based electrolyte, and that ionic transport can be kinetically controlled. Selective Li‐ and Na‐based SEI membranes are produced using Li‐ or Na‐based electrolytes, respectively. The Na‐based SEI allows easy transport of Li ions, while the Li‐based SEI shuts off Na‐ion transport. Na‐ion storage can be manipulated by tuning the SEI layer with film‐forming electrolyte additives, or by preforming an SEI layer on the electrode surface. The Na specific capacity can be controlled to < 25 mAh g−1; ≈ 1/10 of the normal capacity (250 mAh g−1). Unusual selective/preferential transport of Li ions is demonstrated by preforming an SEI layer on the electrode surface and corroborated with a mixed electrolyte. This work may provide new guidance for preparing good ion‐selective conductors using electrochemical approaches.
Palladium‐Catalyzed Cyclization of Free Hydroxyalkenoic Acids: Regio‐ and Chemoselective Access to Methylene Lactones
Authors: Mostinski Yelena , Kotikalapudi Ramesh , Valerio Viviana , Nataf Riva , Tsvelikhovsky Dmitry 
Published: March 2017

AbstractA general and collective synthesis of medium‐sized methylene lactones via controlled cyclizations of easily accessible collective precursors is described. The rapid composition of key–hydroxyalkenoic acid scaffold yields an assembly of oxocanones, oxepanones, and pyranones in a regioselective and stereodirected fashion via palladium‐catalyzed cyclization.magnified image
Chemoselective, Isomerization‐Free Synthesis of N‐Acylketimines from N–H Imines
Authors: Kwon Yearang , Rhee Young Ho , Park Jaiwook 
Published: March 2017

AbstractN‐Acylketimines were synthesized through a ruthenium‐catalyzed generation of N–H ketimines from secondary azides and subsequent acylation with mixed anhydrides under mild conditions. The synthetic scope was broad to give N‐acylimines having various functional groups, including those with aliphatic groups that are prone to tautomerization to the corresponding enamides. In addition, various acyl moieties were accommodated. The synthetic utility of this chemoselective imine generation was illustrated by a highly diastereoselective nucleophilic addition of a Grignard reagent to a cyclic N‐acylimine.magnified image
Synthesis of Thiosulfonates via CuI‐Catalyzed Reductive Coupling of Arenesulfonyl Chlorides Using Na2SO3 or NaHSO3 as Reductants
Authors: Zhao Xuna , Liu Tong‐Xin , Zhang Guisheng 
Published: March 2017

AbstractA mild and efficient method for the synthesis of thiosulfonates has been developed through a CuI‐catalyzed reductive coupling of arenesulfonyl chlorides using Na2SO3 or NaHSO3 as the terminal reductant under a nitrogen atmosphere at room temperature. A broad scope of thiosulfonates was obtained in high to excellent yields via this simple, practical and economical transformation. The ease of handling, the use of low‐cost and readily available reaction materials at room temperature, and the efficiency on a large scale, make this method attractive in both organic synthesis and industrial applications.
Polymerbasierte Halogenbrückendonoren mit selbstheilenden Eigenschaften in Filmen
Authors: Tepper Ronny , Bode Stefan , Geitner Robert , Jäger Michael , Görls Helmar , Vitz Jürgen , Dietzek Benjamin , Schmitt Michael , Popp Jürgen , Hager Martin D. , Schubert Ulrich S. 
Published: March 2017

AbstractDieser Beitrag beschreibt die Synthese einer systematischen Reihe polymerbasierter Anionenrezeptoren und deren umfassende Charakterisierung sowohl in Lösung als auch im Polymerfilm. Erstmals wurden hierbei polymerbasierte Halogenbrückendonoren mittels isothermer kalorimetrischer Titration vermessen, um die Abhängigkeit der Anionenaffinität von verschiedenen Parametern (d. h. monomerbasiert gegenüber polymerbasiert, Halogenbrücken im Vergleich zu Wasserstoffbrücken sowie Ladungsassistenz) zu beurteilen. Durch die Kombination dieser Donorsysteme mit einem carboxylathaltigem Copolymer konnten supramolekulare Polymernetzwerke mit ausgezeichnetem intrinsischem Selbstheilungsverhalten hergestellt werden. FT‐Raman‐Spektroskopie und Nanoindentierungsmessungen der durch die Halogenbrücken vernetzten Polymerfilme dienten zur Aufklärung des thermisch induzierten Selbstheilungsmechanismus. Diese selbstheilenden Polymere basierend auf Halogenbrücken ebnen den Weg für neue Anwendungsgebiete der Halogenbrückendonoren.
Yttrium‐Catalyzed Intramolecular Hydroalkoxylation/Claisen Rearrangement Sequence: Efficient Synthesis of Medium‐Sized Lactams
Authors: Zhou Bo , Li Long , Zhu Xin‐Qi , Yan Juan‐Zhu , Guo Yi‐Lin , Ye Long‐Wu 
Published: March 2017

AbstractAn efficient yttrium‐catalyzed intramolecular hydroalkoxylation/Claisen rearrangement sequence has been achieved, thus enabling facile access to a diverse array of valuable medium‐sized lactams. Furthermore, a mechanistic rationale for this novel cascade reaction is well supported by a variety of control experiments.
One‐Pot Transformation of Simple Furans into Octahydroindole Scaffolds
Authors: Kalaitzakis Dimitris , Triantafyllakis Myron , Ioannou Georgios I. , Vassilikogiannakis Georgios 
Published: March 2017

AbstractA highly efficient and general singlet‐oxygen‐initiated one‐pot transformation of readily accessible furans into octahydroindole scaffolds has been developed.
Coordination Polymer Framework Based On‐Chip Micro‐Supercapacitors with AC Line‐Filtering Performance
Authors: Yang Chongqing , Schellhammer Karl Sebastian , Ortmann Frank , Sun Sai , Dong Renhao , Karakus Melike , Mics Zoltán , Löffler Markus , Zhang Fan , Zhuang Xiaodong , Cánovas Enrique , Cuniberti Gianaurelio , Bonn Mischa , Feng Xinliang 
Published: March 2017

AbstractOn‐chip micro‐supercapacitors (MSCs) are important Si‐compatible power‐source backups for miniaturized electronics. Despite their tremendous advantages, current on‐chip MSCs require harsh processing conditions and typically perform like resistors when filtering ripples from alternating current (AC). Herein, we demonstrated a facile layer‐by‐layer method towards on‐chip MSCs based on an azulene‐bridged coordination polymer framework (PiCBA). Owing to the good carrier mobility (5×10−3 cm2 V−1 s−1) of PiCBA, the permanent dipole moment of azulene skeleton, and ultralow band gap of PiCBA, the fabricated MSCs delivered high specific capacitances of up to 34.1 F cm−3 at 50 mV s−1 and a high volumetric power density of 1323 W cm−3. Most importantly, such MCSs exhibited AC line‐filtering performance (−73° at 120 Hz) with a short resistance–capacitance constant of circa 0.83 ms.
Enantioselective Iridium‐Catalyzed Allylic Substitution with 2‐Methylpyridines
Authors: Liu Xi‐Jia , You Shu‐Li 
Published: March 2017

AbstractAn enantioselective iridium‐catalyzed allylic substitution with a set of highly unstabilized nucleophiles generated in situ from 2‐methylpyridines is described. Enantioenriched 2‐substituted pyridines, which are frequently encountered in natural products and pharmaceuticals, could be easily constructed by this simple method in good yields and excellent enantioselectivity. The synthetic utility of the pyridine products is demonstrated through the synthesis of a key intermediate of a reported Na+/H+ exchanger inhibitor and the total synthesis of (−)‐lycopladine A.
Physicochemical stability of calcium alginate beads immobilizing TiO2 nanoparticles for removal of cationic dye under UV irradiation
Authors: Lam Weng‐Hoong , Chong Meng Nan , Horri Bahman Amini , Tey Beng‐Ti , Chan Eng‐Seng 
Published: March 2017

ABSTRACTRecently, there have been considerable interests to immobilize photocatalyst in alginate beads for removing pollutants from water sources. However, the feasibility of using alginate beads in industry largely depends on its long‐term stability during operation. This study investigated the physicochemical stability of alginate/titanium dioxide beads (Alg/TiO2) when exposed to UV irradiation in aqueous environment. The degradation of Alg/TiO2 beads was evident because the diameter and mass of the beads was reduced by 12% and 40%, respectively, after 120 h of irradiation. A substantial amount of TiO2 was leached into the external medium. Consequently, the removal efficiency of model cationic dye was found to reduce after every process cycle. Morphological analysis showed the formation of cavities on the surface of the Alg/TiO2 beads. Interestingly, the blank alginate beads degraded more rapidly than the Alg/TiO2 beads, confirming the UV‐shielding effect of TiO2. Nevertheless, this study reveals the need to improve the UV stability of alginate‐based beads before they can be considered for practical application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45002.
Poly(urethane acrylate)‐based gel polymer films for mechanically stable, transparent, and highly conductive polymer electrolyte applications
Authors: Lee Eun‐Jin , Park Kyung‐Hun , Lee Young‐Hee , Kim Kyung‐Geun , Jeong Yeon Uk , Kim Sung Yeol , Kim Han‐Do 
Published: March 2017

ABSTRACTPolymer electrolytes are attractive for the applications in conventional electrochemical devices and emerging flexible devices. In this study, we developed a poly(urethane acrylate)‐based gel polymer electrolyte with excellent mechanical stability, optical transparency, and a high ionic conductivity. These polymer electrolytes showed excellent dimensional stability and an elastomer‐like behavior with a Shore A hardness in the range of 20–40. The optical transmittance values of these polymers films were over 80% in the visible range. Their ionic conductivities were controlled via changes in the concentration of the linker, dimethylol propionic acid (DMPA), and the lithium salt incorporated into the polymer. The maximum ionic conductivity reached 3.7 mS/cm at room temperature (∼23 °C) when the DMPA/poly(ethylene glycol) molar ratio was 0.25, and the ionic conductivity was found to be proportional to the salt concentration. We believe that these polymer electrolytes will be useful in various electrochemical applications where flexibility, high ionic conductivity, and transparency in the electrolytes are necessary. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45009.
Small dams need consideration in riverscape conservation assessments
Authors: Mantel Sukhmani Kaur , Rivers‐Moore Nick , Ramulifho Pfananani 
Published: March 2017

Abstract

Small, off‐channel dams are generally ignored in impact assessments owing to limited information and spatial resolution issues. Previous research on South African rivers showed correlative links between high density of small dams and associated reductions in low flows, poorer water quality, and impoverished aquatic macroinvertebrate communities that were dominated by opportunistic taxa instead of specialist groups.
Since small dams are usually associated with catchment transformation (for example, vineyards, stock farming and exotic timber plantations), they are convenient surrogates of the impacts of catchment transformation on river functionality. Here, an index of cumulative small dams for South Africa, Lesotho and Swaziland is presented and evaluated.
Fifty‐two per cent of the water management catchments in the study region exceeded the threshold for the cumulative small dams density (SDD) index above which river functionality is compromised. This estimate of potentially affected catchments is considered to be conservative for reasons discussed.
The index results are compared with a recent systematic biodiversity planning exercise for setting biodiversity targets for freshwater areas of South Africa. Although the systematic planning included in‐stream small dams within 50 m of a river, analysis showed that 36% of all quaternaries that have high SDD score overlap with river reaches classified as ‘natural’ or ‘largely natural’.
Disregarding dams outside the 50 m buffer area equates to ignoring the majority of small dams (94%) in South Africa, and it is recommended that aquatic conservation assessments include the SDD index as a cost layer for prioritizing rivers for rehabilitation and conservation.
Water Solubilization of Fullerene Derivatives by β‐(1,3‐1,6)‐d‐Glucan and Their Photodynamic Activities toward Macrophages
Authors: Ikeda Atsushi , Iizuka Tatsuya , Maekubo Naotake , Nobusawa Kazuyuki , Sugikawa Kouta , Koumoto Kazuya , Suzuki Toshio , Nagasaki Takeshi , Akiyama Motofusa 
Published: March 2017

AbstractAnionic and neutral fullerene derivatives were dissolved in water by using β‐(1,3‐1,6)‐d‐glucan (β‐1,3‐glucan) as a solubilizing agent. In the water‐solubilized complexes, the concentrations of fullerene derivatives were ≈0.30 mm and the average particle sizes were ≈90 nm. The β‐1,3‐glucan‐complexed fullerene derivative with a carboxylic acid was found to have higher photodynamic activity toward macrophages under visible‐light irradiation (λ>610 nm) than other β‐1,3‐glucan‐complexed fullerene derivatives. This result suggests that carboxylic acid moieties in the complex enhance the binding affinity with β‐1,3‐glucan receptors on the surface of macrophages when the β‐1,3‐glucan is recognized. In contrast, all β‐1,3‐glucan‐complexed fullerene derivatives showed no photodynamic activity toward HeLa cells under the same conditions.
Queue discharge patterns at signalized intersections with green signal countdown device and long cycle length
Authors: Tang Keshuang , Dong Keran , Chung Edward 
Published: March 2017

SummaryTwo apparent features that prevail at signalized intersections in China are green signal countdown device and long cycle lengths. The objective of this study is to investigate the impacts of green signal countdown device and long cycle length on queue discharge patterns and to discuss its implications on capacity estimation in the context of China's traffic. At five typical large intersections in Shanghai and Tianjin, 11 through lanes were observed, and 9251 saturation headways were obtained as valid samples. Statistical analyses indicate that the discharge process of queuing vehicles can be divided into three distinct stages according to the discharge flow rate: a start‐up stage, a steady stage, and a rush stage. The average time for queuing vehicles to reach a stationary saturation flow rate, that is, the start‐up stage, was found to be approximately 20–30 seconds; the rush stage usually occurs during the phase transition period. The finding is contrary to the conventional assumption that the discharge rate reaches a maximum value after the fourth vehicle is discharged and then remains constant during the green time until the queue is completely dissolved. The capacity estimation errors that might arise from the conventional methods are discussed through a comparative study and a sensitivity analysis that are based on the identified queue discharge patterns. In addition, a piecewise linear regression method was proposed in order to reduce such errors. The proposed method can be used for capacity estimation at signalized intersections with the identified queue discharge patterns. Copyright © 2017 John Wiley & Sons, Ltd.