bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linking basin‐scale and pore‐scale gas hydrate distribution patterns in diffusion‐dominated marine hydrate systems
Authors: Nole Michael , Daigle Hugh , Cook Ann E. , Hillman Jess I. T. , Malinverno Alberto 
Published: February 2017

AbstractThe goal of this study is to computationally determine the potential distribution patterns of diffusion‐driven methane hydrate accumulations in coarse‐grained marine sediments. Diffusion of dissolved methane in marine gas hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse‐grained sediments over geologic time. Using one‐dimensional compositional reservoir simulations, we examine hydrate distribution patterns at the scale of individual sand layers (1–20 m thick) that are deposited between microbially active fine‐grained material buried through the gas hydrate stability zone (GHSZ). We then extrapolate to two‐dimensional and basin‐scale three‐dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including pore size distribution, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the distribution of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin gas hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges of thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. Furthermore, we find that hydrate in fine‐grained material can preserve high hydrate saturations in nearby thin sands with burial.
On the geochemical heterogeneity of rivers draining into the straits and channels of the Canadian Arctic Archipelago
Authors: Alkire Matthew B. , Jacobson Andrew D. , Lehn Gregory O. , Macdonald Robie W. , Rossi Matthew W. 
Published: February 2017

AbstractTen rivers across northern Canada and the Canadian Arctic Archipelago (CAA) were sampled during spring 2014 and summer 2015 to investigate their geochemical heterogeneity for comparison against larger North American (i.e., Mackenzie and Yukon Rivers) and Siberian rivers. In general, rivers draining the western and/or northern regions of the study area have higher solute concentrations and lower 87Sr/86Sr ratios compared to rivers draining the eastern and/or southern regions. The inorganic geochemical signatures largely reflect the bedrock geology, which is predominately carbonate in the western and/or northern regions and silicate in the eastern and/or southern regions. Riverine δ18O values primarily correlate with latitude, with only a few exceptions. Measurements of total alkalinity (TA) were combined with a regional analysis of bedrock geology and extrapolated to produce a range for the mean characteristic TA of rivers draining into the straits and channels of the CAA (628–819 µeq kg−1). Combining this estimate with contributions from the Mackenzie River yields a revised North American river runoff TA of 935–1182 µeq kg−1, which is much lower than that of the Mackenzie River (1540 µeq kg−1). This lower concentration suggests that TA may not be used to distinguish between North American and Siberian river contributions in regions such as Davis Strait.
Pore‐scale modeling of wettability alteration during primary drainage
Authors: Kallel W. , van Dijke M. I. J. , Sorbie K. S. , Wood R. 
Published: February 2017

AbstractWhile carbonate reservoirs are recognized to be weakly‐to‐moderately oil‐wet at the core‐scale, pore‐scale wettability distributions remain poorly understood. In particular, the wetting state of micropores (pores <5 µm in radius) is crucial for assessing multiphase flow processes, as microporosity can determine overall pore‐space connectivity. While oil‐wet micropores are plausible, it is unclear how this may have occurred without invoking excessively high capillary pressures. Here we develop a novel mechanistic wettability alteration scenario that evolves during primary drainage, involving the release of small polar non‐hydrocarbon compounds from the oil‐phase into the water‐phase. We implement a diffusion/adsorption model for these compounds that triggers a wettability alteration from initially water‐wet to intermediate‐wet conditions. This mechanism is incorporated in a quasi‐static pore‐network model to which we add a notional time‐dependency of the quasi‐static invasion percolation mechanism. The model qualitatively reproduces experimental observations where an early rapid wettability alteration involving these small polar species occurred during primary drainage. Interestingly, we could invoke clear differences in the primary drainage patterns by varying both the extent of wettability alteration and the balance between the processes of oil invasion and wetting change. Combined, these parameters dictate the initial water saturation for waterflooding. Indeed, under conditions where oil invasion is slow compared to a fast and relatively strong wetting change, the model results in significant non‐zero water saturations. However, for relatively fast oil invasion or small wetting changes, the model allows higher oil saturations at fixed maximum capillary pressures, and invasion of micropores at moderate capillary pressures.
The relationship between loading history and proximal femoral diaphysis cross‐sectional geometry
Authors: Niinimäki Sirpa , Narra Nathaniel , Härkönen Laura , Abe Shinya , Nikander Riku , Hyttinen Jari , Knüsel Christopher , Sievänen Harri 
Published: February 2017

AbstractObjectivesWe investigated the relationship between loading history and bone biomechanical properties used in physical activity reconstructions. These bone properties included bone bending and torsional strength (J), cortical area (CA), the direction of the major axis (theta angle), and element shape ratios determined from cross sections of standardized bone length. In addition, we explored the applicability of anatomically determined cross sections.MethodsOur material consisted of hip and proximal thigh magnetic resonance images of Finnish female athletes (N = 91) engaged in high‐jump, triple‐jump, endurance running, swimming, power‐lifting, soccer and squash; along with a group of active non‐athlete individuals (N = 20). We used regression analysis for size‐adjustment, and the extracted residuals were then used to compare differences in the bone properties between groups.ResultsWe found that triple‐jumpers, soccer players, and squash players had the greatest values in CA and J, swimmers and non‐athletes had the smallest, whereas high‐jumpers, power‐lifters, and endurance runners exhibited interim values. No between‐the‐group differences in element shape ratios or theta angles were found. We found that influences of activity were similar regardless of whether standardized length or anatomically determined cross sections were used.ConclusionsExtreme (triple‐jump) and directionally inconsistent loading (soccer and squash) necessitate a more robust skeleton compared to directionally consistent loading (high‐jump, power‐lifting, and endurance running) or non‐impact loading (swimming and non‐athletes). However, not all of these relationships were statistically significant. Thus, information gained about physical activity using bone properties is informative but limited. Accounting for the limitations, the method is applicable on fragmented skeletal material as anatomically determined cross sections can be used.
Copper‐Catalyzed Synthesis of Tetrasubstituted Allenes from Quaternary Ammonium Salts and Grignard Reagents
Authors: Ma Shengming , Liu Qi , Tang Xinjun , Cai Yujuan 
Published: February 2017

AbstractAlthough the synthesis of allenes has made considerable progress, methods for tetrasubstituted allenes are still limited. In this paper, the CuBr2‐catalyzed cross‐coupling reaction of Grignard reagents and propargylic ammonium salts in tetrahydrofuran at 60 °C under argon delivered tetrasubstituted allenes in good to excellent yields. The reaction is thought to proceed by an SN2′ pathway.
Study on the Photoinduced Nitric‐Oxide‐Releasing Ability of 4‐Alkoxy Furoxans
Authors: Matsubara Ryosuke , Takazawa Saori , Ando Akihiro , Hayashi Masahiko , Tohda Rei , Tsubaki Motonari 
Published: February 2017

AbstractNitric oxide (NO) has a range of biological activities in living systems. Because NO is a gaseous and short‐lived molecule, the development of methods to enable a temporally and spatially resolved NO supply has been a challenging task. Herein, 3‐aryl‐4‐alkoxy furoxan is revealed as a potent photoinduced NO donor. Whilst negligible levels of NO release were observed under ambient fluorescent light, a significant amount of NO was released under UV irradiation (λ=300–400 nm). A thiol mediator that contains a pendant amino group was found to be indispensable for NO release from aryl alkoxy furoxans. Analysis of the NO‐releasing mechanism of aryl alkoxy furoxan revealed that the main co‐product was the corresponding aryl nitrile, which was derived from fragmentation of the furoxan ring. Based on these results, we have proposed a plausible mechanism for photoinduced NO release, in which the key steps are nucleophilic attack of the thiol at the 3‐position of the furoxan, thereby leading to fragmentation of the furoxan ring, and the formation of a tetrahydrothiazole that contains a C‐nitroso group. A comparison of fluorofuroxan and alkoxy furoxan is also discussed.
Quantifying the impact of µCT‐scanning of human fossil teeth on ESR age results
Authors: Duval Mathieu , Martín‐Francés Laura 
Published: February 2017

AbstractFossil human teeth are nowadays systematically CT‐scanned by palaeoanthropologists prior to any further analysis. It has been recently demonstrated that this noninvasive technique has, in most cases, virtually no influence on ancient DNA preservation. However, it may have nevertheless an impact on other techniques, like Electron Spin Resonance (ESR) dating, by artificially ageing the apparent age of the sample. To evaluate this impact, we µCT‐scanned several modern enamel fragments following the standard analytical procedures employed by the Dental Anthropology Group at CENIEH, Spain, and then performed ESR dose reconstruction for each of them. The results of our experiment demonstrate that the systematic high‐resolution µCT‐scanning of fossil hominin remains introduces a nonnegligible X‐ray dose into the tooth enamel, equivalent to 15–30 Gy depending on the parameters used. This dose may be multiplied by a factor of ∼8 if no metallic filter is used. However, this dose estimate cannot be universally extrapolated to any µCT‐scan experiment but has instead to be specifically assessed for each device and set of parameters employed. The impact on the ESR age results is directly dependent on the magnitude of the geological dose measured in fossil enamel but could potentially lead to an age overestimation up to 40% in case of Late Pleistocene samples, if not taken into consideration.
Combined Phosphoramidite‐Phosphodiester Reagents for the Synthesis of Methylene Bisphosphonates
Authors: Engelsma Sander B. , Meeuwenoord Nico J. , Overkleeft Hermen S. , van der Marel Gijsbert A. , Filippov Dmitri V. 
Published: February 2017

AbstractA new class of phosphanylmethylphosphonate reagents has been developed to enable the controlled synthesis of methylene bisphosphonate mono‐ and diesters. Condensation of such reagents with an alcohol of choice through azole‐mediated phosphoramidite chemistry followed by in situ oxidation provides orthogonally protected methylene bisphosphonate tetraesters. Global deprotection of the tetraester leads to terminal methylene bisphosphonates. Alternatively, selective deprotection at the terminal phosphonate followed by a condensation between the acquired methylene bisphosphonate triester and a second alcohol leads to methylene bisphosphonates diesters.
Double Concave Cesium Encapsulation by Two Charged Sumanenyl Bowls
Authors: Spisak Sarah N. , Wei Zheng , Rogachev Andrey Yu. , Amaya Toru , Hirao Toshikazu , Petrukhina Marina A. 
Published: February 2017

AbstractThe controlled reaction of Na and Cs, two alkali metals of different ionic sizes and binding abilities, with sumanene (C21H12) affords a novel type of organometallic sandwich [Cs(C21H11−)2]−, which crystallized as a solvent‐separated ion pair with a [Na(18‐crown‐6)(THF)2]+ cation (where THF=tetrahydrofuran). The unprecedented double concave encapsulation of a metal ion by two bowl‐shaped sumanenyl anions in [Cs(C21H11−)2]− was revealed crystallographically. Evaluation of bonding and energetics of the remarkable product was accomplished computationally (B2PLYP‐D/TZVP/ZORA), providing insights into its formation.
Nanostructured Materials for Heterogeneous Electrocatalytic CO2 Reduction and their Related Reaction Mechanisms
Authors: Zhang Lei , Zhao Zhi‐Jian , Gong Jinlong 
Published: February 2017

AbstractThe gradually increased concentration of carbon dioxide (CO2) in the atmosphere has been recognized as the primary culprit for the rise of the global mean temperature. In recent years, development of routes for highly efficient conversion of CO2 has received much attention. This Review describes recent progress on the design and synthesis of solid‐state catalysts for the electrochemical reduction of CO2. The significance of this catalytic conversion is presented, followed by the general parameters for CO2 electroreduction and a summary of the reaction apparatus. We also discuss various types of solid catalysts based on their CO2 conversion mechanisms. We summarize the crucial factors (particle size, surface structure, composition, etc.) determining the performance for electroreduction.
NiII Coordination to an Al‐Based Metal–Organic Framework Made from 2‐Aminoterephthalate for Photocatalytic Overall Water Splitting
Authors: An Yang , Liu Yuanyuan , An Pengfei , Dong Juncai , Xu Benyan , Dai Ying , Qin Xiaoyan , Zhang Xiaoyang , Whangbo Myung‐Hwan , Huang Baibiao 
Published: February 2017

AbstractThe aluminum‐based metal–organic framework (MOF) made from 2‐aminoterephthalate is a photocatalyst for oxygen evolution. This MOF can be modified by incorporating Ni2+ cations into the pores through coordination to the amino groups, and the resulting MOF is an efficient photocatalyst for overall water splitting.
Influence of propylene‐based elastomer on stress‐whitening for impact copolymer
Authors: Lu Ying , Sun Yingying , Li Lan , Men Yongfeng 
Published: February 2017

ABSTRACTTwo pure impact copolymer polypropylenes (ICP), one pure homo‐polypropylene (HPP) and their compounds with different type and fraction of Vistamaxx™ propylene‐based elastomer (“Vistamaxx”) were used to investigate the stress whitening activated in the impact processes via ultra‐small‐angle X‐ray scattering technique. The whitening presented in ICP is confirmed to be caused by the interfaces existed between ethylene‐propylene (EP) rubber and polypropylene matrix, such kind whitening is apparently unlike the one initiated in the crystal phase of HPP. In this study, Vistamaxx with high crystallinity can adjust the compatibility of EP rubber and PP matrix which results in a reduction of interfaces, thus, a phenomenon of reduced stress whitening can be observed in blends of ICP with Vistamaxx. However, the enhancement of stress whitening can be found in blends of ICP with Vistamaxx which occupied low crystallinity. Such behaviors can be assigned to the poor compatibility between Vistamaxx and PP matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44747.
Processing‐structure‐property relationship in rigid polyurethane foams
Authors: Kabakci Elif , Sayer Göksin , Suvaci Ender , Uysal Oktay , Güler İhsan , Kaya Metin 
Published: February 2017

ABSTRACTRigid polyurethane (PU) foam is used as a thermal insulating and supporting material in domestic refrigerator/freezers and it is produced by reaction injection molding (RIM) process. There is a need to improve the thermal property of rigid PU foam but this is still a challenging problem. Accordingly, this work investigates the RIM process parameters to evaluate their effects on rigid PU foam's structure and hence property. It has been found that mold temperature is a key parameter whereas curing time has negligible effect on structure of PU foam. Cell size, strut thickness, and foam density have been found very critical in controlling the thermal and mechanical properties. Upper and lower values of 30 to 32 kg/m3 density are critical to observe contribution of radiation and solid conductivity separately. Finally, PU foam with 160 µm average cell size, 16 µm strut thickness, below 10% open cell content, and 30 to 32 kg/m3 density allow obtaining better thermal insulation without significant reducing in the compressive strength. The presented work provides a better understanding of processing‐structure‐property relationship to gain knowledge on producing high‐quality rigid PU foams with improved properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44870.
Resorcinol in high solid phenol−formaldehyde resins for foams production
Authors: Liu Juan , Chen Ri‐Qing , Xu Yu‐Zhi , Wang Chun‐Peng , Chu Fu‐Xiang 
Published: February 2017

ABSTRACTThe acid curing agent content and foaming temperature could be reduced by improving the resol reactivity. In this study, highly active and solid phenol−resorcinol−formaldehyde copolymer resins (PRFRs) with different resorcinol/phenol (R/P) molar ratios and formaldehyde/(phenol + resorcinol) [F/(P + R)] molar ratios were synthesized through the copolymerization of resorcinol, formaldehyde, and phenol. Phenol−resorcinol−formaldehyde foams (PRFFs) were prepared with synthetic PRFRs. The results showed that PRFR‐2 exhibited higher reactivity, faster curing speed, and better thermal stability. In addition, the foam produced with the PRFR‐2 had improved mechanical and flame retardation properties and a compressive strength of 0.18 MPa, a flexural strength of 0.25 MPa, and a limited oxygen index (LOI) greater than 37%. The increased reactivity of the PRFRs correlated with the changing mechanical properties of PRFFs because of the effects of resorcinol and the molar ratio of formaldehyde to phenol and resorcinol. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44881.
Effects of the chain‐extender content on the structure and performance of poly(lactic acid)–poly(butylene succinate)–microcrystalline cellulose composites
Authors: Cao Zheng , Lu Ying , Zhang Cheng , Zhang Qian , Zhou An , Hu Yanchao , Wu Dun , Tao Guoliang , Gong Fanghong , Ma Wenzhong , Liu Chunlin 
Published: February 2017

ABSTRACTComposites of poly(lactic acid) (PLA) with poly(butylene succinate) (PBS) and microcrystalline cellulose (MCC) as reinforcements of the polymer matrix were prepared by melt blending to improve the brittleness of PLA. As a reactive compatibilizer, a chain extender was used in an attempt to solve the composites’ interfacial problems and to improve their mechanical properties; Fourier transform infrared spectroscopy indicated that the chain extender functionally reacted with PLA, PBS, and MCC mainly through end carboxyls or end hydroxyls. Scanning electron microscopy indicated that the chain extender significantly improved the cohesive interfacial forces. Differential scanning calorimetry and X‐ray diffraction showed that the chain extender inhibited crystallization, and these effects were greater when its percentage was increased. The addition of chain extender improved the tensile and impact strength of the composites, and this improvement was proportional to the chain‐extender percentage. However, the elongation at break decreased when the chain‐extender percentage was over 0.5% because of mild crosslinking within the resin matrix. Rheology indicated that the complex viscosity and storage and loss moduli of the composites increased with increasing amount of chain extender; this indicated that the addition of chain extender improved the melt strength and processability of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44895.
Preparation of chitin‐CdTe quantum dots films and antibacterial effect on Staphylococcus aureus and Pseudomonas aeruginosa
Authors: Wansapura Poorna Tharaka , Dassanayake Rohan Suranga , Hamood Abdul , Tran Phat , Moussa Hanna , Abidi Noureddine 
Published: February 2017

ABSTRACTNovel chitin–cadmium‐tellurium quantum dot (Chitin‐CdTeQD) hybrid films combining chitin and CdTe quantum dots (CdTeQDs) were prepared via a facile aqueous synthesis route at room temperature. Films were characterized by high‐resolution field emission scanning electron microscopy (HR‐FESEM) and energy dispersive X‐ray (EDX) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and X‐ray diffraction analysis (XRD). Antibacterial activity was studied on both Gram‐positive (Staphylococcus aureus) and Gram‐negative (Pseudomonas aeruginosa) bacteria. Antibacterial properties were investigated with agar diffusion testing assay and with confocal laser scanning microscopic image analysis. Chitin–CdTeQD films exhibited an excellent antibacterial activity against both Gram‐positive and Gram‐negative bacteria. Chitin–CdTeQD films might be a desirable antibacterial material for wide range of biomedical applications including wound dressing, burn treatment, drug delivery systems, packaging, ophthalmology, and implants. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44904.
“Europe” in Greece: Lay constructions of Europe in the context of Greek immigration debates
Authors: Andreouli Eleni , Figgou Lia , Kadianaki Irini , Sapountzis Antonis , Xenitidou Maria 
Published: February 2017

AbstractIn this paper, we analyse discourses about Europe in Greek debates about immigration and citizenship and highlight the complexities of “Europeanness” as a symbolic resource for argumentation in these debates. Our data consist of lay discourses from 2 rounds of online public deliberation (2009–2010 and 2015) about a controversial new citizenship law in Greece. Our analysis shows that Europe is an ambivalent category. On the one hand, Europe symbolises progress, but, on the other hand, it is also constructed in terms of decline and “contamination” by multiculturalism. Further, our analysis shows that the category of Europe can be mobilised in contradictory ways, in order to support arguments for and against citizenship rights for migrants. The paper concludes with a discussion of the ways in which constructions of Europe are implicated in processes of othering and inclusion in the context of current immigration debates. Copyright © 2017 John Wiley & Sons, Ltd.