bluuebunny/crossref_metadata_2025_split huggingface dataset:
From connected pathway flow to ganglion dynamics
Authors: Rücker M. , Berg S. , Armstrong R. T. , Georgiadis A. , Ott H. , Schwing A. , Neiteler R. , Brussee N. , Makurat A. , Leu L. , Wolf M. , Khan F. , Enzmann F. , Kersten M. 
Published: May 2015

AbstractDuring imbibition, initially connected oil is displaced until it is trapped as immobile clusters. While initial and final states have been well described before, here we image the dynamic transient process in a sandstone rock using fast synchrotron‐based X‐ray computed microtomography. Wetting film swelling and subsequent snap off, at unusually high saturation, decreases nonwetting phase connectivity, which leads to nonwetting phase fragmentation into mobile ganglia, i.e., ganglion dynamics regime. We find that in addition to pressure‐driven connected pathway flow, mass transfer in the oil phase also occurs by a sequence of correlated breakup and coalescence processes. For example, meniscus oscillations caused by snap‐off events trigger coalescence of adjacent clusters. The ganglion dynamics occurs at the length scale of oil clusters and thus represents an intermediate flow regime between pore and Darcy scale that is so far dismissed in most upscaling attempts.
Earthward and tailward flows in the plasma sheet
Authors: Zhang L. Q. , Wang J. Y. , Baumjohann W. , Rème H. , Dunlop M. W. 
Published: May 2015

AbstractUtilizing C3/Cluster satellite observations from the year of 2001 to 2006, we investigated the earthward flow (EF) and tailward flow (TF) at Bz > 0 in the plasma sheet. We found that the EF and the TF have similar spatial distributions. Both characteristics are independent of the distance beyond 14 RE. Both flows are deflected while closer to the Earth. Statistical results further showed that the EF/TF occur in the central plasma sheet as well as the plasma sheet boundary layer and can be observed during quiet times and periods of geomagnetic activity. A typical event reveals that the EF and the TF have different plasma population. A transition region (TR) can be formed at the interface between the EF and TF. Very significant duskward components appeared in bulk velocities for both populations. It appears that the vortical‐like structure can be formed near the TR. The magnetic field within the TR is twisted and strongly fluctuates. No clear magnetic flux pileups are observed inside the TR.
Solar zenith angle‐dependent asymmetries in Venusian bow shock location revealed by Venus Express
Authors: Chai Lihui , Wan Weixing , Fraenz Markus , Zhang Tielong , Dubinin Eduard , Wei Yong , Li Yi , Rong Zhaojin , Zhong Jun , Han Xiuhong , Futaana Yoshifumi 
Published: May 2015

AbstractIt has been long known that the Venusian bow shock (BS) location is asymmetric from the observations of the long‐lived Pioneer Venus Orbiter mission. The Venus Express (VEX) mission crossed BS near perpendicularly not only in the terminator region but also in the near‐subsolar and tail regions. Taking the advantage of VEX orbit geometry, we examined a large data set of BS crossings observed during the long‐lasting solar minimum between solar cycles 23 and 24 and found that the Venusian BS asymmetries exhibit dependence of solar zenith angle. In the terminator and tail regions, both the magnetic pole‐equator and north‐south asymmetries are observed in Venusian BS location, which is similar to the Pioneer Venus Orbiter (PVO) observation near terminator. However, in the near‐subsolar region, only the magnetic north‐south is observed; i.e., the BS shape is indented inward over magnetic south pole and bulged outward over magnetic north pole. The absence of the magnetic pole‐equator asymmetry in the near‐subsolar region suggests that the magnetic pole‐equator asymmetry is mainly caused by the asymmetric wave propagation rather than the ion pickup process. The evident magnetic north‐south asymmetry in solar minimum, which is not observed by PVO, suggests that even during the low long‐lasting solar minimum, the ion pickup process is very important in Venusian space environment.
Mechanical instability induced by water weakening in laboratory fluid injection tests
Authors: David C. , Dautriat J. , Sarout J. , Delle Piane C. , Menéndez B. , Macault R. , Bertauld D. 
Published: May 2015

AbstractTo assess water‐weakening effects in reservoir rocks, previous experimental studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks fully saturated either with water or with inert fluids. So far, little attention has been paid to the mechanical behavior during fluid injection under conditions similar to enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behavior of the weakly consolidated Sherwood sandstone in laboratory experiments. Our specimens were instrumented with 16 ultrasonic P wave transducers for both passive and active acoustic monitoring during loading and fluid injection to record the acoustic signature of fluid migration in the pore space and the development of damage. Calibration triaxial tests were conducted on three samples saturated with air, water, or oil. In a second series of experiments, water and inert oil were injected into samples critically loaded up to 80% or 70% of the dry or oil‐saturated compressive strength, respectively, to assess the impact of fluid migration on mechanical strength and elastic properties. The fluids were injected with a low back pressure to minimize effective stress variations during injection. Our observations show that creep takes place with a much higher strain rate for water injection compared to oil injection. The most remarkable difference is that water injection in both dry and oil‐saturated samples triggers mechanical instability (macroscopic failure) within half an hour whereas oil injection does not after several hours. The analysis of X‐ray computed tomography images of postmortem samples revealed that the mechanical instability was probably linked to loss of cohesion in the water‐invaded region.
Modeling flood dynamics along the superelevated channel belt of the Yellow River over the last 3000 years
Authors: Chen Yunzhen , Overeem Irina , Kettner Albert J. , Gao Shu , Syvitski James P. M. 
Published: May 2015

AbstractThe Yellow River, China, experienced >1000 levee breaches during the last 3000 years. A reduced‐complexity model is developed in this study to explore the effects of climate change and human activity on flood levels, levee breaches, and river avulsions. The model integrates yearly morphological change along a channel belt with daily river fluxes and hourly evolution of levee breaches. Model sensitivity analysis reveals that under natural conditions, superelevation of the channel belt dominates flood frequency. When there is significant human‐accelerated basin erosion and breach repair, the dominant factors shift to a combination of mean annual precipitation, superelevation, critical shear stress of weak channel banks, and the time interval between breach initiation and its repair. The effect of precipitation on flood frequency is amplified by land use changes in the hinterland, particularly in the erodible Loess Plateau. Uncertainty analysis estimates the most likely values of the dominant factors for six historical periods between 850 B.C. and A.D. 1839, which are used to quantitatively reconstruct flood dynamics. During 850 B.C. to A.D. 1839, when the sediment load increased fourfold, the breach recurrence interval was shortened from more than 500 years to less than 6 years, and the breach outflow rate increased ~27 times. River management practices during A.D. 1579 to A.D. 1839 focused on levees and triggered a severe positive feedback of increased levee heights and flood hazard exacerbation. Raising the levee heights proved to be ineffective for sustainable flood management.
Impact of global SST gradients on the Mediterranean runoff changes across the Plio‐Pleistocene transition
Authors: Colleoni Florence , Cherchi Annalisa , Masina Simona , Brierley Christopher M. 
Published: May 2015

AbstractThis work explores the impact of the development of global meridional and zonal sea surface temperature (SST) gradients on the Mediterranean runoff variability during the Plio‐Pleistocene transition, about 3 Ma. Results show that total annual mean Pliocene Mediterranean runoff is about 40% larger than during the preindustrial period due to more increased extratropical specific humidity. As a consequence of a weakened and extended Hadley cell, the Pliocene northwest Africa hydrological network produces a discharge 30 times larger than today. Our results support the conclusion that during the Pliocene, the Mediterranean water deficit was reduced relative to today due to a larger river discharge. By means of a stand‐alone atmospheric general circulation model, we simulate the separate impact of extratropical and equatorial SST cooling on the Mediterranean runoff. While cooling the equatorial SST does not imply significant changes to the Pliocene Mediterranean hydrological budget, the extratropical SST cooling increases the water deficit due to a decrease in precipitation and runoff. Consequently, river discharge from this area reduces to preindustrial levels. The main teleconnections acting upon the Mediterranean area today, i.e., the North Atlantic Oscillation during winter and the “monsoon‐desert” mechanism during summer already have a large influence on the climate of our Pliocene simulations. Finally, our results also suggest that in a climate state significantly warmer than today, changes of the Hadley circulation could potentially lead to increased water resources in northwest Africa.
Neutron Stars
Authors: Schaffner‐Bielich Jürgen 
Published: May 2015

Abstract

The role of nuclear physics is outlined for the properties of neutron stars. The outer crust of a neutron star consists of a lattice of neutron‐rich nuclei immersed in a sea of electrons, which extends up to the neutron dripline. Beyond the neutron‐drip density, a neutron superfluid forms within a lattice of nuclei, which can build up geometric phases, the nuclear pasta of the crust. The equation of state of the outer core of a neutron star, which consists of neutrons, protons, and leptons only, can be constrained by modern calculations of pure neutron matter. The inner core of a neutron star can harbor exotic dense‐matter phases with strangeness, which can be explored by studying massive pulsars. There emerges a growing interplay of the observations of neutron star properties with the study of the nuclear equation of state and the
quantum chromodynamics
(
QCD
)‐ phase diagram by relativistic heavy‐ion collisions.
Cancer Therapy with Ion Beams
Authors: Kraft Gerhard 
Published: May 2015

Abstract
The main purpose of any radiation therapy is to deliver a dose high enough to kill all tumor cells but to spare the normal tissue around to a maximum extent. In conventional therapy, the tolerance of the normal tissue around the target limits the maximum possible dose to the tumor because of the depth dose profile of photons depositing the highest dose close to the surface. In contrast, all ions are characterized by an inverse depth dose profile with a dose maximum (Bragg maximum) at the end of the range. Therefore, a greater ion dose can be given to a deep‐seated target volume than using X‐rays. In addition, the heavier ions, such as carbon, have a smaller lateral scattering and an increased biological effectiveness at the end of the range that can be restricted to the tumor. Heavy ion beams are therefore more precise and can deliver a greater and biologically more efficient dose to the target volume than any other radiation.
Monitoring the coincident γ‐decay of a few positron‐emitting nuclear fragments, the primary beam can be followed inside the patient's body without any additional radiation burden. But the treatment planning for the high‐precision ion‐beam therapy is more complex than that in conventional photon therapy.
Fundamentals of Controlled Nuclear Fission and Essential Characteristics of Pressurized‐Water Reactors
Authors: Lauer Hartmut 
Published: May 2015

AbstractAmong the nuclear power plants of large capacity currently operating worldwide, the light‐water reactor (LWR) is the dominating technology either as boiling‐water reactors (BWR) or as pressurized‐water reactors (PWR), with the latter being the most frequently operated design. The fundamentals of controlled nuclear fission and the essential characteristics of a nuclear reactor are explained in the chapter. Design, function, and safety concepts of a nuclear power plant are explained taking aPWRas the example.
A numerically stable, finite memory, fast array recursive least squares filter for broadband active noise control
Authors: van Ophem S. , Berkhoff A. P. 
Published: May 2015

SummaryFor broadband active noise control applications with a rapidly changing primary path, it is desirable to find algorithms with a rapid convergence, a fast tracking performance, and a low computational cost. Recently, a promising algorithm has been presented, called the fast‐array Kalman filter, which uses rotation matrices to calculate the filter parameters. However, when this algorithm is implemented, it can show unstable behavior because of finite precision error propagation. In this paper, a novel algorithm is presented, which exhibits the fast convergence and tracking properties and the linear calculation complexity of the fast‐array Kalman filter but does not suffer from the mentioned numerical problems. This is accomplished by running two finite length growing memory recursive least squares filters in parallel and using a convex combination of the two filters when the control signal is calculated. A reset of the filter parameters with proper re‐initialization is enforced periodically. The mixing parameters will be chosen in such a way that the total available information used for the calculation of the control signal will be approximately equal at every time instance. The performance of the filter is shown in numerical simulations and real‐time lab experiments. The numerical experiments show that the algorithm performs better numerically than the fast‐array sliding window recursive least squares filter, while achieving a comparable convergence rate and tracking performance. The real‐time lab experiments confirm the behavior shown in the simulations. Copyright © 2015 John Wiley & Sons, Ltd.
A simplified kinetics model of natural and iron complex catalysed hydrogen peroxide oxidation of starch
Authors: Kumoro Andri Cahyo , Ratnawati R. , Retnowati Diah Susetyo 
Published: May 2015

AbstractHydrogen peroxide is well known as one of environmentally benign reagents for the oxidation of starch. The aim of this work was to develop a simplified model for the describing of mass transfer and reaction kinetics phenomena of non‐catalytic and iron complex catalysed starch oxidation using hydrogen peroxide under alkaline condition. The model was composed based on hydrogen peroxide consumptions for its decomposition and reaction with starch molecules as well as mass transfer between liquid–solid reactants. Effects of starch‐water ratio (S/L), catalyst concentration and pH were evaluated. The results show that both non‐catalytic and iron complex catalysed hydrogen peroxide starch oxidation follows pseudo‐first‐order reaction with respect to hydrogen peroxide concentration. The proposed model satisfactorily describes the overall reaction, where very good agreement with experimental data was obtained. Mass transfer between liquid–solid reactants was likely to be the controlling step for the iron complex catalysed starch oxidation using hydrogen peroxide. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Synergistic effect of organoclay fillers based on fluorinated surfmers for preparation of polystyrene nanocomposites
Authors: Benbayer Chahinez , Saidi‐Besbes Salima , Taffin de Givenchy Elisabeth , Amigoni Sonia , Guittard Frédéric , Derdour Aicha 
Published: May 2015

ABSTRACTNovel fluorinated reactive surfactants were used for the organic modification of monmorillonite clays. These organoclays were used for the preparation of polystyrene−clay nanocomposites by in‐situ free radical polymerization. Reference systems based on hydrocarbon homologous surfmer and nonpolymerizable surfactants were also used to deduce the effect of the fluorine moiety and the polymerizable function on the morphology and thermal stability of the prepared nanocomposites. Different structural parameters of the surfactants were investigated and modulated for the clay modification including: the nature of surfactant (surfmer/classical surfactant, fluorinated, or hydrocarbonated), the length of the fluorinated chain as well as the length of the hydrocarbon spacers linking the ammonium head to the fluorine chain or the polymerizable acrylic function. Wide angle‐X‐ray scattering (WAXD), thermogravimetric analysis (TGA), and electronic microcopies (TEM and SEM) were used to establish a structure‐morphology, thermal properties relationships, and to highlight the key parameters governing the exfoliation process. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42347.
Polyaniline self‐assembled with DTPA: Facilely tuned morphology and properties
Authors: Gibreel Mohammed , Jing Xinli , Li Yu , Liu Yongzhong 
Published: May 2015

ABSTRACTThe effects of pH profile and “soft template” during aniline chemical oxidative polymerization (COP) were investigated and evaluated simultaneously with diethylene triamine pentaacetic acid (DTPA) as a structural directing agent. Formation of PANI nanotubes and nanoparticles, smooth microspheres, and urchin‐like microspheres were illustrated by evaluating the pH profile during aniline COP while considering the “soft template” effects of DTPA. PANI nanosheets with two semicurled edges were found in the system producing nanotubes, which provides an evidence for the “curling mechanism” of PANI nanotube formation. With different pH profiles, chemical structures and aggregation structures of the as‐synthesized PANI micro/nanostructures are similar, whereas their conductivity, wettability, Cr (VI) adsorption, and electrochemical behaviors are distinct. The present study indicates that if properly conducted, pH profile adjustment is more effective than “soft template” to control the morphology and to optimize the performance of PANI micro/nanostructures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42403.
Dielectric studies of composite paper reinforced with polypyrrole coated pulp fibers from wasted egg holders
Authors: Razaq Aamir , Idrees Muhammad , Malik Adeel , Mushtaq Nafeesa , Nadeem Muhammad , Hussain Irshad , Yar Muhammad 
Published: May 2015

ABSTRACTDevelopment of thin, flexible, light‐weight, renewable, low‐cost, and environmentally friendly electrode materials are highly feasible in era of modern disposable electronic technology. This article presents the synthesis and dielectric studies of polypyrrole (PPy) coated pulp fibers, directly collected from wasted egg holder's tray. PPy coated pulp fibers converted into compact sheet for the development of potential renewable and low‐cost electrode materials. The morphology, chemical structure, and thermal stability of naked and PPy coated pulp fibril sheets were investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA), respectively. PPy coated pulp fibers revealed better thermal stability and compactness of sheet morphology. Impedance measurements showed a high value of dielectric constant of 1.15 × 106 at 0.5 Hz and conductivity of 7.45 × 10−4 S/cm at room temperature for PPy coated pulp fibril sheet. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42422.
Increasing mechanical strength of electrospun gelatin nanofibers by the addition of aluminum potassium sulfate
Authors: Siimon Kaido , Mõisavald Karol , Siimon Hele , Järvekülg Martin 
Published: May 2015

ABSTRACTIncreasing mechanical strength of gelatin‐based materials is required to expand the range of their applications, which is desirable because of biocompatibility, biodegradability, and low cost of gelatin. The effect of aluminum potassium sulfate on preparation and properties of nanofibrous gelatin were investigated. Samples were electrospun from 10M aqueous acetic acid and analyzed by scanning electron microscopy (SEM), Fourier transform infrared microscopy (FTIR), energy‐dispersive x‐ray analysis (EDX), and tensile test. The addition of AlK(SO4)2 considerably increases the elastic modulus of the material up to about 10% salt content. The elastic modulus of electrospun gelatin meshes prepared as described in the present work increased from 20 MPa to 70 MPa and the elastic modulus of the fiber material increased from 150 MPa to 620 MPa as the salt content in the fibers increased from 0% to 9.6%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42431.
Investigations on the interactions between naphthalimide‐based anti‐tumor drugs and human serum albumin by spectroscopic and molecular modeling methods
Authors: Cheng Huiyuan , Zou Ting , Xu Yongliang , Wang Ying , Wu Aibin , Dai Jie , Zhang Yezhong , Liu Yi 
Published: May 2015

AbstractThe interactions between the three kinds of naphthalimide‐based anti‐tumor drugs (NADA, NADB, NADC) and human serum albumin (HSA) under simulated physiological conditions were investigated by fluorescence spectroscopy, circular dichroism spectroscopy and molecular modeling. The results of the fluorescence quenching spectroscopy showed that the quenching mechanisms for different drugs were static and their affinity was in a descending order of NADA > NADB > NADC. The relative thermodynamic parameters indicated that hydrophobic force was the predominant intermolecular force in the binding of NAD to HSA, while van der Waals interactions and hydrogen bonds could not be ignored. The results of site marker competitive experiment confirmed that the binding site of HSA primarily took place in site I. Furthermore, the molecular modeling study was consistent with these results. The study of circular dichroism spectra demonstrated that the presence of NADs decreased the α‐helical content of HSA and induced the change of the secondary structure of HSA. Copyright © 2015 John Wiley & Sons, Ltd.
Impact of the MLL1 morphemes on codon utilization and preservation in CpG Islands
Authors: Bina Minou , Wyss Phillip 
Published: May 2015

ABSTRACTPrevious studies have shown that Mixed Lineage Leukemia 1 (MLL1 or MLL) binds a group of CpG‐rich motifs known as morphemes. To examine whether occurrences of MLL1 morphemes in genomic DNA may influence codon utilization, we analyzed the frequency of various 9‐mers in human cDNAs and in total human genomic DNA. We uncovered preferential utilization of GGC for Gly, GCG for Ala, CCG for Pro, and TCG for Ser, in coding sequences (CDSs) that included MLL1 morphemes. We also examined weighted occurrences of CDS 9‐mers in a 30‐base window that moved along each human chromosome. In plots, we observed peaks with fluctuating intensities. High intensity peaks appeared within promoter and exons localized in CpG islands, encompassing sequences that included MLL1 morphemes. High intensity peaks included CCG/GGC repeats, whose expansion may cause neurological disorders and congenital malformations. Such repeats are generated from overlap of a morpheme (CGCCG/CGGCG), which depending on reading frame and orientation would produce runs of Ala, Gly, or Pro in proteins. Overall, our results point to a role for morpheme occurrences on synonymous codon utilization in human genomic DNA and indicate that regulatory instructions are dispersed not only in promoters but also in exons of human genes. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 480–490, 2015.