bluuebunny/crossref_metadata_2025_split huggingface dataset:
Airborne GPS radio occultation refractivity profiles observed in tropical storm environments
Authors: Murphy B. J. , Haase J. S. , Muradyan P. , Garrison J. L. , Wang K.‐N. 
Published: February 2015

AbstractAirborne GPS radio occultation (ARO) data have been collected during the 2010 PRE‐Depression Investigation of Cloud systems in the Tropics (PREDICT) experiment. GPS signals received by the airborne Global Navigation Satellite System Instrument System for Multistatic and Occultation Sensing (GISMOS) are used to retrieve vertical profiles of refractivity in the neutral atmosphere. The system includes a conventional geodetic GPS receiver component for straightforward validation of the analysis method in the middle to upper troposphere, and a high‐sample rate (10 MHz) GPS recorder for postprocessing complex signals that probe the lower troposphere. The results from the geodetic receivers are presented here. The retrieved ARO profiles consistently agree within ~2% of refractivity profiles calculated from the European Center for Medium‐Range Weather Forecasting model Interim reanalyses as well as from nearby dropsondes and radiosondes. Changes in refractivity obtained from ARO data over the 5 days leading to the genesis of tropical storm Karl are consistent with moistening in the vicinity of the storm center. An open‐loop tracking method was implemented in a test case to analyze GPS signals from the GISMOS 10 MHz recording system for comparison with geodetic receiver data. The open‐loop mode successfully tracked ~2 km deeper into the troposphere than the conventional receiver and can also track rising occultations, illustrating the benefit from the high‐rate recording system. Accurate refractivity retrievals are an important first step toward the future goal of assimilating moisture profiles to improve forecasting of developing storms using this new GPS occultation technique.
Formation of Two Homo‐chromophoric H‐Aggregates in DNA‐Assembled Alternating Dye Stacks
Authors: Winiger Christian B. , Langenegger Simon M. , Calzaferri Gion , Häner Robert 
Published: February 2015

AbstractThe understanding and description of collectively excited multichromophores is of crucial importance for many areas of basic and applied research. DNA has been used for the construction of well‐defined heterochromophoric stacks. Electronic coupling among non‐adjacent chromophores of the same type leads to the co‐existence of PDI and pyrene H‐aggregates in hybrids composed of alternating chromophore stacks.
Aktive Zentren und Mechanismen der direkten Oxidation von Benzol zu Phenol an Kohlenstoffkatalysatoren
Authors: Wen Guodong , Wu Shuchang , Li Bo , Dai Chunli , Su Dang Sheng 
Published: February 2015

AbstractDie direkte Oxidation von Benzol zu Phenol mit H2O2 als Oxidationsmittel gilt als umweltfreundlicher Prozess und verläuft sehr effizient an Kohlenstoffkatalysatoren. Es gibt jedoch kontroverse Ansichten bezüglich der Rolle des Kohlenstoffkatalysators und der aktiven Zentren. Hier führen wir eine grundlegende Betrachtung möglicher Reaktionsmechanismen für diese Oxidationsreaktion an niedermolekularen Modellkatalysatoren durch. Unsere Schlussfolgerungen sind auf Raman‐Spektren, statische Sekundärionen‐Massenspektrometrie (SIMS), DFT‐Rechnungen, ATR‐ und UV‐Spektren gestützt. Es wird gefunden, dass Defektstrukturen, welche die Bildung aktiver Sauerstoffspezies begünstigen, die aktiven Zentren darstellen. Ein spezifischer Defekt, der hierbei identifiziert werden konnte, ist die Armchair‐Konfiguration.
Asymmetric Dearomatization of Indoles through a Michael/Friedel–Crafts‐Type Cascade To Construct Polycyclic Spiroindolines
Authors: Zhao Xiaohu , Liu Xiaohua , Mei Hongjiang , Guo Jing , Lin Lili , Feng Xiaoming 
Published: February 2015

AbstractA highly efficient asymmetric dearomatization of indoles was realized through a cascade reaction between 2‐isocyanoethylindole and alkylidene malonates catalyzed by a chiral N,N′‐dioxide/MgII catalyst. Fused polycyclic indolines containing three stereocenters were afforded in good yields with excellent diastereo‐ and enantioselectivities through a Michael/Friedel–Crafts/Mannich cascade. When 2‐substituted 2‐isocyanoethylindoles were used, spiroindoline derivatives were obtained through a Michael/Friedel–Crafts reaction.
Comparison of the degradation and release behaviors of poly(lactide‐co‐glycolide)–methoxypoly(ethylene glycol) microspheres prepared with single‐ and double‐emulsion evaporation methods
Authors: Feng Shuibin , Lu Feng , Wang Yan , Suo Jinping 
Published: February 2015

ABSTRACTThe purpose of this study was to compare the degradation and release behaviors of poly(lactide‐co‐glycolide) (PLGA)–methoxypoly(ethylene glycol) microspheres fabricated by the single‐emulsion evaporation method (DEEM) and double‐emulsion evaporation methods (DEEM). Vancomycin and mizolastine were used as the hydrophilic and hydrophobic model drugs, and they were encapsulated into microspheres through DEEM and SEEM, respectively. The two types of microspheres were similar in size distribution, but the mizolastine‐loaded microspheres showed a much higher encapsulation efficiency than those loaded with vancomycin. Scanning electron microscopy, size, and molecular weight (Mw) analyses during the degradation revealed that the microspheres fabricated by DEEM underwent a bulk degradation process and showed a faster MW reduction rate during the early degradation period than the microspheres fabricated by SEEM, which exhibited a surface‐to‐bulk degradation process according to the Mw and morphological changes. The mass loss rates of the two types of microspheres were similar, but the mean size decrease rates showed a little difference. The mizolastine‐loaded microspheres exhibited an approximately linear release profile after the initial burst release, whereas the vancomycin‐loaded microspheres showed a more severe burst release, a faster release rate, and thus, a shorter time to full release. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41943.
Production of recycled cellulose fibers from waste paper via ultrasonic wave processing
Authors: Guo Xiuyan , Jiang Zhengwu , Li Haoxin , Li Wenting 
Published: February 2015

ABSTRACTRecycling waste paper can be considered as a means to displace the use of natural cellulose fibers applied in building materials, because it is composed mostly of cellulose. The water absorption and special surface area of cellulose fibers are the key properties for their use in building materials. The objective of this article was to study the production of recycled cellulose fibers from waste paper using ultrasonic wave processing. The physical and chemical properties of recycled cellulose fibers, such as water absorption, specific surface area and pore characteristics, etc., were investigated with various testing methods. The results indicated that the ultrasonic cavitation effect was feasible for the preparation of the secondary fibers. When the ultrasonic treatment time lasted for 10 min, the water absorptions of both newsprint fibers and kraft fibers increased significantly and reached the highest values of 12.5 g/g and 11.2 g/g, respectively, which were nearly two times than that of fibers without ultrasonic treatment. With a pretreatment of 20 min, the average length and fineness of recycled cellulose fibers decreased by 4% and 25%, respectively, and the length‐diameter ratio of the recycled cellulose fibers was 1.28 times than that of the untreated fibers, which greatly increased the special surface area of the recycled cellulose fibers. This work also determined that NaOH was useful to improve the physical properties of the recycled cellulose fibers. Because the recycled cellulose fibers after processing, fulfilled several technical indexes, they can be considered as a filling material for used in cement‐based materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41962.
Structural, rheological, and mechanical properties of PA6/SAN/SEBS ternary blend/organoclay nanocomposites
Authors: Babaei Amir , Arefazar Ahmad 
Published: February 2015

ABSTRACTThe aim of this study was to investigate the effect of nanoclay addition on the morphological and mechanical properties of PA6/SAN/SEBS ternary blend. Two different nanoclays with different modifiers and two different mixing sequences were used to investigate the role of thermodynamic and kinetic, respectively, in the nanoclays localization. XRD, SEM, TEM, melt rheology, tensile and Izod impact tests were used to characterize the nanocomposites. Results of characterization of nanocomposites showed that clay localization is a very influential parameter to determine the type of morphology and, consequently, mechanical properties of ternary/clay nanocomposites. It was demonstrated that presence of nanoclay in the matrix results in the increase of stiffness, while localization of nanoclay at the interface improves the toughness and tensile strength. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41969.
Failure process of acrylic polyurethane coating under alternate wetting and drying condition
Authors: Zuo Yu , Zhang Liang , Zhao Xuhui , Tang Yuming , Zhang Xiaofeng 
Published: February 2015

ABSTRACTThe failure process of an acrylic polyurethane coating in simulated sea water under a wet‐dry cyclic condition and immersion condition was studied with the methods of electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FT‐IR), and scanning electron microscope (SEM). The results show that the failure rate of acrylic polyurethane coating under the condition of wet‐dry alternation is obviously greater than that under complete immersion. Under wet‐dry condition, both the porosity and the water absorptivity of the coating are also greater than those under complete immersion condition. Owing to the physical effect of wet‐dry alternation, the fillers in the coating surface layer may fall off and result in micro‐pores, which could multiply the defects in the coating and accelerate the coating degradation. FT‐IR analysis shows that the isocyanate group in the coating not only participates in the curing of coating, but also hydrolyzes with water molecule. The C‐O bonds fracture partly due to hydrolysis of the main molecule chains, which is one reason of the coating failure. The failure process for acrylic polyurethane coating under a wet‐dry cyclic condition is discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41989.
Time‐Dependent Aggregation‐Induced Enhanced Emission, Absorption Spectral Broadening, and Aggregation Morphology of a Novel Perylene Derivative with a Large D–π–A Structure
Authors: Yang Long , Yu Yuyan , Zhang Jin , Ge Feijie , Zhang Jianling , Jiang Long , Gao Fang , Dan Yi 
Published: February 2015

AbstractStrong aggregation‐caused quenching of perylene diimides (PDI) is changed successfully by simple chemical modification with two quinoline moieties through CC at the bay positions to obtain aggregation‐induced enhanced emission (AIEE) of a perylene derivative (Cya‐PDI) with a large π‐conjugation system. Cya‐PDI is weakly luminescent in the well‐dispersed CH3CN or THF solutions and exhibits an evident time‐dependent AIEE and absorption spectra broadening in the aggregated state. In addition, morphological inspection demonstrates that the morphology of the aggregated form of Cya‐PDI molecules changed from plate‐shaped to rod‐like aggregates under the co‐effects of time and water. An edge‐to‐face arrangement of aggregation was proposed and discussed. The fact that the Cya‐PDI aggregates show a broad absorption covering the whole visible‐light range and strong intermolecular interaction through π–π stacking in the solid state makes them promising materials for optoelectric applications.
Recent Progresses in Ceramic Hollow‐Fiber Membranes
Authors: Dashti Amir , Asghari Morteza 
Published: February 2015

AbstractMembrane technology is one of the most important aspects in separation processes. Hollow fibers are one of the emerging technologies that had a new growth spurt during the past decades. Ceramic membranes have outstanding stability at high temperatures (> 100 °C), at extreme pH, and in fouling environments. In this article, recent progresses on ceramic hollow‐fiber membranes are discussed. The characterizations of membranes, particularly by different methods, are reported. New ceramics, especially perovskites and composites of ceramics, and new techniques are introduced in making high performance hollow fibers. New applications of ceramic hollow fibers are also discussed in detail.
Morphology Control of Polysulfone Membranes in Filtration Processes: a Critical Review
Authors: Abdelrasoul Amira , Doan Huu , Lohi Ali , Cheng Chil‐Hung 
Published: February 2015

AbstractPolysulfone (PSU) membranes have been widely applied in microfiltration and ultrafiltration processes due to their excellent properties, such as chemical inertness across the entire pH range, compressive strength, and thermal stability. Despite these advantages, the application of PSU membranes in filtration processes has often been restricted due to their hydrophobic nature, which results in serious membrane fouling and a reduced permeate flux. Moreover, PSU membranes suffer from several disadvantages, including bulky structure, low binding force between fibers, and poor mechanical properties. The key factor in the development and application of polymeric membranes is the control of its polymeric morphology due to the significant influence of membrane morphology on the membrane performance. Effective techniques of controlling PSU membrane morphology are accessed, and the effects of the morphological control on mechanical properties, chemical stability, membrane performance, and membrane fouling are investigated. Findings from various individual studies were analyzed and discussed in order to provide a critical review of this subject. The results emphasized that the membrane pore size and surface porosity mostly governs PSU membrane morphology, which enhances membrane performance and reduces membrane fouling.
Mixed Carbonates as Useful Substrates for a Fluorogenic Assay for Lipases and Esterases
Authors: Zadlo Anna , Koszelewski Dominik , Borys Filip , Ostaszewski Ryszard 
Published: February 2015

AbstractMixed carbonates of 7‐hydroxy‐4‐methylcoumarin were shown to be a new class of probe for fluorogenic assays. They are promising substrates for fingerprinting enzyme hydrolytic activity, and proved particularly useful because of the low level of nonspecific degradation and ease of synthesis. They are highly relevant for screening lipase and esterase libraries. These advantages make umbelliferyl carbonates highly suitable substrates for high‐throughput screening. Moreover, we report the use of chiral fluorogenic carbonates as enantiopreference probes.
Controlled Surface Segregation Leads to Efficient Coke‐Resistant Nickel/Platinum Bimetallic Catalysts for the Dry Reforming of Methane
Authors: Li Lidong , Zhou Lu , Ould‐Chikh Samy , Anjum Dalaver H. , Kanoun Mohammed B. , Scaranto Jessica , Hedhili Mohamed N. , Khalid Syed , Laveille Paco V. , D'Souza Lawrence , Clo Alain , Basset Jean‐Marie 
Published: February 2015

AbstractSurface composition and structure are of vital importance for heterogeneous catalysts, especially for bimetallic catalysts, which often vary as a function of reaction conditions (known as surface segregation). The preparation of bimetallic catalysts with controlled metal surface composition and structure is very challenging. In this study, we synthesize a series of Ni/Pt bimetallic catalysts with controlled metal surface composition and structure using a method derived from surface organometallic chemistry. The evolution of the surface composition and structure of the obtained bimetallic catalysts under simulated reaction conditions is investigated by various techniques, which include CO‐probe IR spectroscopy, high‐angle annular dark‐field scanning transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, extended X‐ray absorption fine structure analysis, X‐ray absorption near‐edge structure analysis, XRD, and X‐ray photoelectron spectroscopy. It is demonstrated that the structure of the bimetallic catalyst is evolved from Pt monolayer island‐modified Ni nanoparticles to core–shell bimetallic nanoparticles composed of a Ni‐rich core and a Ni/Pt alloy shell upon thermal treatment. These catalysts are active for the dry reforming of methane, and their catalytic activities, stabilities, and carbon formation vary with their surface composition and structure.
Numerical Simulation of Single‐Bubble Dynamics in High‐Viscosity Ionic Liquids Using the Level‐Set Method
Authors: Carvajal Danilo , Carlesi Carlos , Meléndez‐Vejar Victor , Vásquez‐Sandoval Dreidy , Monteverde‐Videla Alessandro H. A. , Bensaid Samir 
Published: February 2015

AbstractTwo numerical models for studying the dynamics of formation and rise of single bubbles in high‐viscosity ionic liquids were implemented using the level‐set method. The models describe two stages of bubble dynamics: bubble formation at the inlet nozzle and bubble displacement across the column. The models were experimentally validated through a laboratory‐scale bubble column using water‐glycerol mixtures and two imidazolium‐type ionic liquids. The models were consistent with the experimental tests for Reynolds numbers < 5. Outside this range, the models tend to underestimate the bubble terminal velocity, which can be explained by the effect of the high velocity and pressure gradients close to the gas‐liquid interface. The models also predicted the velocity and pressure fields near the bubble surface before and after detachment.
Size, Charge, and Stability of Fully Serine‐Based Catanionic Vesicles: Towards Versatile Biocompatible Nanocarriers
Authors: Silva Sandra G. , Vale M. Luísa C. do , Marques Eduardo F. 
Published: February 2015

AbstractVesicles based on mixed cationic and anionic surfactants (catanionic vesicles) offer a number of advantageous colloidal features over conventional lipid‐based vesicles, namely spontaneity in formation, long‐term stability, and easy modulation of size and charge. If biocompatibility is added through rational design of the chemical components, the potential for biorelated applications further emerges. Here, we report for the first time on two catanionic vesicle systems in which both ionic amphiphiles are derivatized from the same amino acid—serine—with the goal of enhancing aggregate biocompatibility. Phase behavior maps for a mixture with chain length symmetry, 12Ser/12‐12Ser, and another with asymmetry, 16Ser/8‐8Ser, are presented, for which regions of vesicles, micelles, and coexisting aggregates are identified. For the asymmetric mixture, detailed phase behavior and microstructure characterization have been carried out based on surface tension, light microscopy, cryo‐SEM, cryo‐TEM, and dynamic light scattering analysis. Vesicles are found with tunable mean size, pH, and zeta potential. Changes in aggregate shape with varying composition and the effect of preparation methods and aging on vesicle features and stability have been investigated in detail. The results are discussed in the light of self‐assembly models and related catanionic systems reported before. A versatile system of robust vesicles is thus presented for potential applications.
Mechanistic Insights into the Luminescent Sensing of Organophosphorus Chemical Warfare Agents and Simulants Using Trivalent Lanthanide Complexes
Authors: Dennison Genevieve H. , Johnston Martin R. 
Published: February 2015

AbstractOrganophosphorus chemical warfare agents (OP CWAs) are potent acetylcholinesterase inhibitors that can cause incapacitation and death within minutes of exposure, and furthermore are largely undetectable by the human senses. Fast, efficient, sensitive and selective detection of these compounds is therefore critical to minimise exposure. Traditional molecular‐based sensing approaches have exploited the chemical reactivity of the OP CWAs, whereas more recently supramolecular‐based approaches using non‐covalent interactions have gained momentum. This is due, in part, to the potential development of sensors with second‐generation properties, such as reversibility and multifunction capabilities. Supramolecular sensors also offer opportunities for incorporation of metal ions allowing for the exploitation of their unique properties. In particular, trivalent lanthanide ions are being increasingly used in the OP CWA sensing event and their use in supramolecular sensors is discussed in this Minireview. We focus on the fundamental interactions of simple lanthanide systems with OP CWAs and simulants, along with the development of more elaborate and complex systems including those containing nanotubes, polymers and gold nanoparticles. Whilst literature investigations into lanthanide‐based OP CWA detection systems are relatively scarce, their unique and versatile properties provide a promising platform for the development of more efficient and complex sensing systems into the future.
Synthesis, Characterisation and Crystal Structures of Two Bi‐oxadiazole Derivatives Featuring the Trifluoromethyl Group
Authors: Kettner Marcos A. , Klapötke Thomas M. , Witkowski Tomasz G. , von Hundling Felix 
Published: February 2015

AbstractThe synthesis, characterisation, and crystal structure determination of the closely related compounds 3,3′‐bi‐(5‐trifluoromethyl‐1,2,4‐oxadiazole) and 5,5′‐bi‐(2‐ trifluoromethyl‐1,3,4‐oxadiazole) are reported. These two compounds are known for their bioactivity; however, in this study they serve as model compounds to evaluate the suitability of the heterocyclic oxadiazole ring system for energetic materials when the fluorine atoms in the exocyclic CF3 groups are substituted successively by nitro groups. Quantum chemical calculations for the bi‐1,3,4‐ oxadiazole derivatives with difluoronitromethyl, fluorodinitromethyl, and trinitromethyl groups have been carried out and predict promising energetic performances for both explosive and propulsive applications.
Hydrogen Spillover Enhanced Hydroxyl Formation and Catalytic Activity Toward CO Oxidation at the Metal/Oxide Interface
Authors: Jin Yuekang , Sun Guanghui , Xiong Feng , Ding Liangbing , Huang Weixin 
Published: February 2015

AbstractH2‐promoted catalytic activity of oxide‐supported metal catalysts in low‐temperature CO oxidation is of great interest but its origin remains unknown. Employing an FeO(111)/Pt(111) inverse model catalyst, we herewith report direct experimental evidence for the spillover of H(a) adatoms on the Pt surface formed by H2 dissociation to the PtFeO interface to form hydroxyl groups that facilely oxidize CO(a) on the neighboring Pt surface to produce CO2. Hydroxyl groups and coadsorbed water play a crucial role in the occurrence of hydrogen spillover. These results unambiguously identify the occurrence of hydrogen spillover from the metal surface to the noble metal/metal oxide interface and the resultant enhanced catalytic activity of the metal/oxide interface in low‐temperature CO oxidation, which provides a molecular‐level understanding of both H2‐promoted catalytic activity of metal/oxide ensembles in low‐temperature CO oxidation and hydrogen spillover.