bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collisions between protoplanets: data analysis and classification
Authors: Nouda Akiyoshi , Emori Hiroyuki , Nakazawa Kiyoshi 
Published: August 2014

Abstract
Collisions between protoplanets are common events in the later stage of the planetary formation process. Protoplanets grew into present-day planets through these collisional events. It is therefore necessary to obtain information about redistribution of mass and angular momentum between colliding two bodies in order to study the growth rates of planets and the origin of their spin. We have started a series of systematic studies on this theme, and this is our first report. Here, we concentrate on the impact between one protoplanet, which has one Earth mass, and another protoplanet with 0.06 Earth mass. The motion of two bodies are pursued numerically by the SPH simulation method. We change the minimum distance between the two bodies as the variable parameter to specify their orbital angular momentum. For each value of the parameter, we repeat the numerical simulations and obtain final states of bodies. Such various final states are examined by criteria developed to distinguish some clusters formed by many SPH particles. We determine instantaneous orbital elements for relative motion between central protoplanet and each cluster. From this information, we forecast the destiny of each cluster, for example, to be merged into the target body or trapped. Then we determine the initial conditions that result in final characteristic states. The 5 states are the merging state in which the impactor is absorbed to the target, the multiple impact state in which the impactor collides with the target again and again, the disruption escaping state in which the impactor is tidally disrupted and a large part of the impactor escapes from the target, the trapping state in which the impactor is trapped by the target, and the passing state in which the impactor passes through as it is.
A study on the evaluation of the geoid-quasigeoid separation term over Pakistan with a solution of first and second order height terms
Authors: Sadiq Muhammad , Ahmad Zulfiqar , Akhter Gulraiz 
Published: August 2014

Abstract
An attempt has been made to evaluate the geoid-quasigeoid separation term over Pakistan by using solutions of terms involving first and second order terrain heights. The first term, involving the Bouguer anomaly, has a significant value and requires being incorporated in any case for determination of the geoid from the quasigoidal solution. The results of the study show that the second term of separation, which involves the vertical gravity anomaly gradient, is significant only in areas with very high terrain elevations and reaches a maximum value of 2–3 cm. The integration radius of 18 km for the evaluation of the vertical gravity anomaly gradient was found to be adequate for the near zone contribution in the case of the vertical gravity anomaly gradient. The Earth Gravity Model EGM96 height anomaly gradient terms were evaluated to assess the magnitude of the model dependent part of the separation term. The density of the topographic masses was estimated with the linear operator of vertical gravity anomaly gradient using the complete Bouguer anomaly data with an initial arbitrary density of 2.67 g/cm3 to study the effect of variable Bouguer density on the geoid-quasigeoid separation. The density estimates seem to be reasonable except in the area of very high relief in the northern parts. The effect of variable density is significant in the value of the Bouguer anomaly-dependent geoid-quasigeoid separation and needs to be incorporated for its true applicability in the geoid-quasigeoid separation determination. The geoid height (N) was estimated from the geoid-quasigeoid separation term plus global part of height anomaly and terrain-dependant correction terms. The results were compared with the separation term computed from EGM96-derived gravity anomalies and terrain heights to estimate its magnitude and the possible amount of commission and omission effects.
The large tsunami of 26 December 2004: Field observations and eyewitnesses accounts from Sri Lanka, Maldives Is. and Thailand
Authors: Papadopoulos Gerassimos A. , Caputo Riccardo , McAdoo Brian , Pavlides Spyros , Karastathis Vassilios , Fokaefs Anna , Orfanogiannaki Katerina , Valkaniotis Sotiris 
Published: August 2014

Abstract
Post-event field surveys were conducted and measurements were taken in Sri Lanka and Maldives about two weeks after the catastrophic Indian Ocean tsunami of 26 December 2004. The measurements taken were cross-checked after interviewing with local people. In the southwest, south and east coastal zones of Sri Lanka maximum water levels ranging from h = 3 m to h = 11 m a.m.s.l. were estimated. The highest values observed were in the south of the island: Galle h ∼ 10 m, Hambantota h ∼ 11m. Maximum inundation of d ∼ 2 km was observed in Hambantota. The heavy destruction and thousands of victims caused in coastal communities, buildings and infrastructure, like railways and bridges, is attributed not only to physical parameters, like the strength of the tsunami hydrodynamic flow, coastal geomorphology and the wave erosional action in soil, but also to anthropogenic factors including the increased vulnerability of the non-RC buildings and the high population density. Local people usually described the tsunami as a series of three main waves. The leading wave phase was only a silent sea level rise of h ≤ 1.5 m and d ≤ 150 m, while the second wave was the strongest one. The first two waves occurred between 09:00 and 09:30 local time, depending on the locality. It is well documented that near Galle, southern part, the strong wave arrived at 09:25:30. In the west coast the third wave was a late arrival which possibly represents reflection phases. In Maldives, three waves were also reported to arrive between 09:00 and 09:30 local time. Maximum water level was only h ∼ 3 m in Laamu Atoll, which is interpreted by the wave amplitude damping by the coral reef to the east of the island complex as well as to that the tsunami did not arrived at high tide time. Damage was observed in several islands of Maldives but this was minimal as compared to the heavy destruction observed in Sri Lanka. About 25 Greek eyewitnesses, who happened to experience the tsunami attack in Padong and Blue Lagoon Port of Phuket island as well as in Maya Bay, Phi-Phi islands, Thailand, were interviewed on the basis of a standard questionnaire. The first sea motion was a retreat of at least 100 m. Then, two main waves arrived, the first being the strong one occurring at about 09:55–10:05 local time, with h ∼ 6m in Padong causing significant destruction and human victims. The collected information clearly indicates that the tsunami propagated as the leading crest wave to the west side, e.g. in Sri Lanka and Maldives, and as the leading trough wave to the east, e.g. in Thailand.
Mitarbeiterführung in einer monopolistischen Kultur
Authors: Bartlakowski Katja 
Published: August 2014

Zusammenfassung:
Für manche Vorgesetzte im Bibliothekswesen mag in der beziehungsorientierten Mitarbeiterführung keine besondere Herausforderung liegen. So verwundert es nicht, dass Führungsthemen in der bibliothekarischen Literatur häufig auf der aufgabenbezogenen Ebene behandelt werden. Doch gerade die nicht aufgabenbezogenen Führungsthemen haben es in sich. Wer glaubt, Mitarbeiter etwa fördern und weiterentwickeln zu können, ohne die kulturellen Bedingungen des öffentlichen Dienstes zu verstehen, wird nicht selten erstaunt darüber sein, wie vielfältig die Abwehrmechanismen sein können. Häufig ist dann die Rede von Demotivation und Minderleistung auf Seiten der Mitarbeiter. Und wer glaubt, kulturelle Veränderungen und Organisationsentwicklungen vornehmen zu können, ohne die Spielregeln des öffentlichen Dienstes zu berücksichtigen, wird mitunter über die Hartnäckigkeit der Beharrungskräfte verblüfft sein, die am Traditionellen festhalten. Wie funktioniert der öffentliche Dienst und wie kann Mitarbeiterführung in einer monopolistischen Verwaltungskultur gelingen?
Sm based initiators for the ring-opening polymerization of L-lactide
Authors: Agarwal Seema , Karl Marc , Dehnicke Kurt , Greiner Andreas 
Published: August 2014

AbstractRing-opening polymerizations of L-lactide were carried out in the presence of Sm(II) (SmI2/Sm) and the Sm(III) complex [Sm(m-Cl){N(SiMe3)2}2(THF)]2 (Me: CH3, THF: tetrahydrofuran). The polymerizations were performed using different mole ratios of monomer to initiator and for different time intervals. The complexes were found to be active polymerization catalysts and led to the synthesis of semicrystalline, optically active poly(L-lactide) retaining about 95.5% of the optical activity. This shows that - with the initiator systems used - polymerization proceeds with the retention of configuration at the chiral carbon atom.
Molecular weight control and end group functionalization of polynorbornene by Ni(II)-initiated polymerization of norbornene in the presence of ethylene and ɑ-olefins
Authors: Mast Christian , Krieger Matthias , Dehnicke Kurt , Greiner Andreas 
Published: August 2014

AbstractHigh-molecular-weight vinyl-type polynorbornene (PN) was obtained in high yields by a highly active nickel-based phosphorane iminato complex in the presence of methylaluminoxane. Termination of norbornene polymerization by functionalized ɑ-olefins yielded soluble end group functionalized polynorbornenes of controlled molecular weight. The impact of the ɑ-olefins on yield and Mn depends significantly on the sterical situation at the olefins. No proof for the incorporation of the olefin at any other position than the chain end was observed. Considerations based on yields and Mn suggest that the Ni hydride species, which is most likely formed upon β-H elimination reaction in the scheme of olefin addition to the growing PN chain, initiates a new PN chain; in other words, chain transfer occurs through β-H elimination reaction.
Bis(η5-cyclopentadienyl)bistriphenylsilanolatozirconium( IV): a new precursor for ethylene polymerization catalysis
Authors: Altomare Angelina , Candian Roberta , Michelotti Marco , Pampaloni Guido , Ciardelli Francesco 
Published: August 2014

AbstractTrialkylsilanols were reported to modify and also to improve the catalytic performance in ethylene polymerization when added to zirconocene/methylaluminoxane (MAO) systems. In order to obtain more information about the chemistry involved, a new stable catalytic precursor was investigated in this work. The precursor bis(h5-cyclopentadienyl)bistriphenylsilanolatozirconium(IV) [ZrCp2(OSiPh3)2] was compared to ZrCp2(CH3)2 and ZrCp4, which can generate ZrCp2(OSiPh3)2 in situ on triphenylsilanol addition. In ethylene polymerization, ZrCp2(OSiPh3)2 exibits a comparable activity and a larger stability than dicyclopentadienylzirconium complexes. On addition of triphenylsilanol to zirconocenes, the productivity increased and the molecular weight sharply decreased, thus suggesting the occurrence of ligand substitution in solution. The reported results are discussed with reference to the proposed mechanism of ethylene polymerization with the conventional ZrCp2Cl2/MAO system.
Kinetic and Monte-Carlo modelling of hyperbranched polymerisation
Authors: Galina Henryk , Lechowicz Jaromir B. 
Published: August 2014

AbstractAfter some comments on the size and conformation of dendrimer molecules, models of the polymerisation of AB2 monomers that leads to hyperbranched polymers are reviewed. The models are (i) a kinetic one that takes into account changes in the reactivity of B groups as well as intramolecular reactions, and (ii) the equivalent Monte-Carlo model. The results of application of the kinetic model to the polymerisation system AB2 + B3 are also presented.
Reactions of polystyrene radicals in a monomer-free atom transfer radical polymerization system
Authors: Yoshikawa Chiaki , Goto Atsushi , Fukuda Takeshi 
Published: August 2014

AbstractPolystyrene radicals (PS•) were produced in high concentration using ω-bromopolystyrene (PS-Br) and α,ω-dibromopolystyrene (Br-PS-Br) in conjunction with Cu(I)Br following the atom transfer technique. A proper choice of the activator system led the PS-Br adduct to a maximum extent of coupling (by recombination), qmax = 0.91, as estimated by gel permeation chromatography. On the other hand, the fraction of chains terminated by disproportionation was estimated to be 0.07 ± 0.04 by 1H NMR. When the radical concentration [PS•] was not high enough, the chain transfer reaction competed with termination, and qmax remained low. For the bifunctional adduct Br-PS-Br, the coupling reaction produced ‘polymers’ of a variety of chain lengths, whose distribution obeyed the theory of random coupling, when q was lower than about 0.5. The high extent of coupling (qmax ≈ 0.9) achievable in short time (< 10 min) suggests practical applicability of this reaction.
Time-resolved FTIR/FTNIR spectroscopy: powerful tools to investigate diffusion processes in polymeric films and membranes
Authors: Musto Pellegrino , Ragosta Giuseppe , Mensitieri Giuseppe 
Published: August 2014

AbstractThe application of time-resolved FTIR spectroscopy to investigate diffusion processes in polymers is described. Two thermosetting systems have been studied: a tetrafunctional epoxy resin cured with an aromatic diamine hardener, and a ternary formulation comprising the above components plus a bismaleimide co-monomer. Spectroscopic monitoring of water diffusion, both in the Mid and in the Near IR frequency ranges, yielded accurate and reproducible kinetic curves from which it was possible to evaluate the absolute parameters of diffusion (diffusivity and activation energy). These were found to compare favourably with the values obtained by conventional gravimetric methods. The molecular interactions between the penetrant molecules and the polymer networks were also investigated and it was shown that, in the system containing the bismaleimide component, the fraction of water molecules hydrogen-bonded to the network decreases significantly.
pH-Dependence of the morphology of micelles formed by poly(2-vinylpyridine)-block-poly(ethylene oxide) copolymers in water
Authors: Gohy Jean-François , Mores Sandrine , Varshney Sunil K. , Zhang Jian-Xin , Jérôme Robert 
Published: August 2014

AbstractThe morphology of micelles formed by two poly(2-vinylpyridine)-blockpoly( ethylene oxide) (P2VP-b-PEO) copolymers has been studied in phosphatebuffered water by dynamic light scattering and transmission electron microscopy. Spherical micelles are observed when the P2VP block is the minor component of the diblock copolymer. When P2VP dominates the composition, transition from spheres-to-rods-to-vesicles takes place in a narrow pH range that straddles the pKa of P2VP. This transition is controlled by the degree of protonation of the P2VP blocks. At high pH, the copolymer precipitates from the solution.
Interpenetrating polydicyclopentadiene/polyacrylate networks obtained by simultaneous non-interfering frontal polymerization
Authors: Fiori Stefano , Mariani Alberto , Ricco Laura , Russo Saverio 
Published: August 2014

AbstractInterpenetrating polymer networks made of dicyclopentadiene and methyl methacrylate or tri(ethylene glycol) dimethacrylate have been successfully prepared by non-interfering frontal polymerization. The role of catalyst and free radical initiator relative amounts, as well as of monomer ratio, has been thoroughly studied. The conditions under which a pure frontal polymerization occurs, and the related values of both front velocity and maximum temperature reached by the reaction, are presented and discussed.
Three-dimensional radical polymerization
Authors: Korolev Gennadii V. , Bubnova Maria L. 
Published: August 2014

AbstractThis is an analytical review on kinetics and mechanism of threedimensional radical polymerization (TDRP) of multifunctional vinyl monomers (oligomers) having two or more double bonds per molecule. The period (1960 - 1977) of establishing the fundamental kinetic law of TDRP and the principal characteristics of its mechanism, i.e., microheterogeneity, is briefly described. New intense progress in the field of TDRP (during the recent decade) resulting from the development of new technologies based on this technique (fiber-optic engineering, information technology, etc.) has received much consideration. The methodological peculiarities of investigations on TDRP kinetics and mechanism, which are a result of the complex conditions of highly structured reaction media inherent in TDRP processes, are described. Particular attention is given to techniques of structuralphysical investigation (a consistent complex of methods including ESR, NMR, diffusion and radiation probing, mechanics and thermomechanics) sensitive to structural microheterogeneity in the range 10-6 - 10-4 cm. The perspectives of macromolecular design based on TDRP data are analyzed including latest approaches as the employment of a ‘living’ chain mode. This review covers three monographs in Russian, reflecting three sequential stages of TDRP development from 1960 till 1995 using acrylic oligomers as an example (most of the investigations were carried out at the Institute of Chemical Physics RAS). The bibliography includes 197 references.
Direct interchain exchange reaction in a polymer blend: evolution of the block weight distribution
Authors: Kudryavtsev Yaroslav V. , Govorun Elena N. 
Published: August 2014

AbstractThe kinetics of an interchain exchange reaction in homogeneous polymer blends is studied theoretically. A set of kinetic equations describing the evolution of the block weight distribution is derived. It is demonstrated that the process may be divided into a fast and a slow stage. The former results in the almost full disappearance of homopolymer chains. Simultaneously, the block weight distribution becomes close to the Flory distribution. In the course of the slow stage, the average block lengths decrease to values typical of a completely random copolymer. It is explicitly shown that for an initial blend of homopolymers characterized by the Flory distribution, the transient block weight distribution takes the Flory form starting from the onset of the reaction. The copolymer composition is proved to change in the course of the fast stage of the process. Previous attempts to address the problem are discussed.
Novel unsaturated ε-caprolactone polymerizable by ringopening and ring-opening metathesis mechanisms
Authors: Lou Xudong , Detrembleur Christophe , Lecomte Philippe , Jérôme Robert 
Published: August 2014

AbstractRing-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) of an unsaturated ε-caprolactone, 6,7-dihydro-2(3H)-oxepinone (DHO2), are alternative routes to produce unsaturated aliphatic polyesters with the same molecular structure. Polymerization of DHO2 initiated by Al isopropoxide in toluene at room temperature or at 0°C proceeds by a coordination-insertion mechanism, although intramolecular transesterification takes place beyond complete monomer conversion. The molecular weight distribution is narrow as long as monomer conversion does not exceed 90%. Ring-opening metathesis polymerization of DHO2 initiated by Schrock’s Mo-based catalyst, 1, at 60°C allows higher molecular weight unsaturated polyester to be prepared, even though an intramolecular side reaction also operates. The structure of poly(DHO2) synthesized by ROP and ROMP is the same, as confirmed by 1H, 13C NMR, and FT-IR spectra. Copolymers of DHO2 with norbornene, cis-cyclooctene, and 1,5-cyclooctadiene have been successfully prepared.
Continuous metathesis reactions by molybdenum carbene complexes supported on inorganic carriers
Authors: Preishuber-Pflügl Peter , Eder Elisabeth , Stelzer Franz 
Published: August 2014

AbstractMolybdenum carbene complexes supported on Al2O3/methylaluminoxane/ diol based carriers were tested in continuous metathesis reactions. For investigations on the stability of the heterogenized complexes, a small tubular reactor filled with catalyst powder was used. When mixing cyclic monomers with chain-transfer agents, we were able to run ring-opening metathesis polymerization (ROMP) via the supported carbenes in a continuous process. Furthermore, continuous acyclic metathesis reaction (ACM) and ring-closing metathesis reaction (RCM) were investigated. Results show that the stability of these molybdenum carbene complexes depends on the concentration of methylidene carbenes formed during the reactions.
Synthesis of rodlike ruthenium(II) coordination polymers having metal-nitrogen and metal-carbon bonds in their main chains
Authors: Schmelz Oliver , Rehahn Matthias 
Published: August 2014

AbstractWell-defined coordination polymers are described whose main chains are held together by pseudo-octahedral ruthenium(II) complexes in which five ligands are nitrogen and one ligand is carbon. In the first step of polymer synthesis, the bis-tridentate ligand 4,4''-bis[4'-(2,2':6',2''-terpyridine)]-2',5'-dihexyl-p-terphenyl is treated with two equivalents of ruthenium(III) chloride. The resulting dinuclear metal-monomer is subsequently activated by exchanging the remaining three chloro ligands at each ruthenium center by acetone as a more easily substitutable ligand. The activated metal monomer is treated with equimolar amounts of 4,4''- bis[4'-(6'-phenyl-2,2'-bipyridine)]-2',5'-dihexyl-p-terphenyl as a bis-tridentate ligand monomer. During this conversion, rodlike chains grow through the formation of two further metal-nitrogen bonds and one carbon-nitrogen bond at every ruthenium center. The homogeneous constitution of the readily soluble polymers is proven, and their degrees of polycondensation are roughly estimated to be Pn ≥ 20, using 1H and 13C NMR spectroscopy. UV-vis absorption spectra show the polymers to behave like chains of electronically independent metal complexes. Due to the carbon-ruthenium bond, however, λmax appears at a longer wavelength (approx. 530 nm) than in the related coordination compounds with only nitrogen-ruthenium bonds. There, λmax is around 500 nm.
Two-dimensional chromatography of complex polymers. 3. Full analysis of polystyrene-poly(methyl methacrylate) diblock copolymers
Authors: Pasch Harald , Mequanint Kibret , Jörg Adrian 
Published: August 2014

AbstractPoly(styrene-block-methyl methacrylate)s were fully analyzed by liquid chromatography at the critical point of adsorption (LC-CC) and two-dimensional chromatography. Operating at chromatographic conditions corresponding to the critical points of the homopolymers polystyrene and poly(methyl methacrylate), the block lengths distributions for the different blocks of the block copolymers were determined quantitatively. Information on the amounts and molar mass distributions of homopolymers and coupling products that were identified in the samples as by-products was obtained by on-line coupled 2D chromatography. It was shown that a complete picture of the molecular heterogeneity of block copolymers can be obtained only when information from different chromatographic experiments is combined. Size exclusion chromatography alone is inappropriate for evaluating the molecular heterogeneity of such samples.