bluuebunny/crossref_metadata_2025 huggingface dataset:
An Analytical Model of the Conveying Behaviour of Closely Intermeshing Co-rotating Twin Screw Extruders
Authors: Michaeli W. , Grefenstein A.
Published: December 2013

Closely intermeshing, co-rotating, twin-screw extruders are increasingly being used for polymer preparation and reactive extrusion. For a theoretical description of these processes, not only the mechanism of reaction kinetics but also aspects of heat transfer and in particular the conveying behaviour of modular twin-screw extruders must be taken into account. Using practical examples, this work sets out to evaluate the possibility of predicting process parameters such as melt temperature, drive power, degree of filling and pressure build-up as functions of screw geometry. To this end, trials with two twin-screw extruders of different size were carried out.
Viscoelastic Simulations of Stratified Bicomponent Extrusion through Slit Dies
Authors: Barakos G. , Mitsoulis E.
Published: December 2013

Numerical simulations have been performed of viscoelastic flow in double-layer coextrusion of polymer melts. The constitutive equation used is a realistic integral model of the K-BKZ type, which can describe the viscoelastic memory of polymer melts. In particular, coextrusion of a typical PS/HDPE system through a slit die has been simulated. The model constants have been determined using experimental data available in the literature. The simulation results reveal bending of the extrudate. The occurrence of bending can be justified using the relative values of the rheological properties of the melts. Bending can be eliminated for certain extrusion rate regions while it is dominant in others.
Modelling of a Viscous Non-Newtonian Polymer Melt in a List/Buss Kneader and Comparison to Experiment
Authors: Lyu M.-Y. , White J. L.
Published: December 2013

A theoretical and experimental study of the behavior of a viscous non-Newtonian polymer melt in a List/Buss Kneader is presented. The modelling study for viscous non-Newtonian behavior considers the dynamics of flow including the influences of screw oscillations and interrupted screw flights. Calculations are made using different methods for various individual Kneader elements which consider (i) pumping capabilities, (ii) leakage flows through the slices in interrupted flights, (iii) pressure distributions and flow fluxes. Predictions of pressure profiles, fill factors, and positions of starvation in modular machines are made. An experimental study which uses polypropylene considers the distributions of polymer in modular screws with different screw configurations. The experimental results are compared to the flow simulation.
The Extensional Flow Mixer, EFM
Authors: Luciani A. , Utracki L. A.
Published: December 2013

There are several reports indicating that deformation and breakup of dispersed drops is easier in extensional flow field than that in shear. This is particularly true for the systems containing the dispersed phase significantly more viscous than the matrix, e.g., blends in which the viscosity ratio λ – ηdisp/ηmatrix≥3.8. These reports led to development of an extensional flow mixer, EFM, a device in which multicomponent, multiphase system [e.g., polymer alloys, blends, master-batches, filled systems] can be hydrodynamically mixed by flowing through a series of convergent/divergent regions of increasing intensity To be effective, EFM must be attached to a machine capable of melting and pressurizing the compound, preferably a single-screw extruder, SSE.

In this paper efficiency of two compounding systems is compared, the first is made of a SSE and an EFM, while the second is a twin-screw extruder, TSE To evaluate the efficiency three types of blends, all characterized by high viscosity ratio, λ ≥ 3.8, were used: (i) high density polyethylene dispersed in polystyrene, HDPE/PS (ii) polypropylene impact-modified by addition of an ethylene-propylene elastomer, EPR/PP, and (iii) ultrahigh molecular weight polyethylene added to high density polyethylene, UHMWPE/HDPE System (i) was used to study the effect of compounding on blend's morphology – the dispersion from the SSE + EFM compounding unit was significantly finer than that from TSE. System (ii) was selected to examine usefulness of EFM for impact modification. The results demonstrated that SSE + EFM provided milder compounding conditions that less shear-degraded PP than TSE The impact strength of specimens prepared in SSE + EFM was superior to that of blends compounded in TSE. The system (iii) was studied to examine the relative merit of SSE + EFM over TSE to produce a finer dispersion of the UHMWPE domains that in turn would result in better dissolution of this ultrahigh molecular weight fraction. Again in this case the SSE + EFM compounder outperformed TSE – the dissolution of UHMWPE was significantly better without parallel degradation of the resin.
A Study on the Reactive Compatibilization of a PBT/LCP Blend: Catalyst Effect
Authors: Lee J. Y. , Jang J. , Hong S. M. , Hwnag S. S. , Seo Y. , Kim K. U.
Published: December 2013

The in situ compatibilization of poly(butylene terephthalate) (PBT) with liquid crystalline polymer (LCP) via catalyzed transesterification reaction was examined through thermal, rheological, morphological and mechanical studies. The addition of catalyst, dibutyltindilaurate, was found to promote the transesterification between PBT and LCP. Maintenance of high vacuum environment was required to produce the high molecular weight copolymers in the reactor, which, acting at the interface, diminished the size of the dispersed phase (LCP) and enhanced interfacial adhesion that led to an early increase of the flexural strength. Flexural strength was reduced after long time reaction due to the chain scission. Transesterification confirmed by NMR spectroscopic analysis played a major role in the interchange process.
Rheology of Layered Thermoplastic Matrix Composites during Compression Molding
Authors: Leterrier Y. , G'Sell C.
Published: December 2013

In view of optimizing the industrial compression molding process of thermoplastic composites, the rheological and microstructural behavior of a polypropylene/glass fiber composite is investigated in model squeeze-flow geometries. The overall stress / strain behavior of the material at various compression rates is recorded and the induced orientation of the fibers is investigated by means of a special electron microscopic characterization method. By contrast to pure polypropylene, it is shown that in the high speed range, the macroscopic flow process is controlled by both the viscous extension and the relative sliding of parallel fibrous layers, the latter becoming unstable when the flow undergoes a rapid transition from divergent to convergent. Under high pressure, voids are dissolved in the polymer melt. In the case of non-isothermal compression, the rheology of the composite is not significantly affected by the cooling of the surface layers. The multilayer plug-flow model based on the sliding mechanism of viscous layers is found to reproduce correctly the experimental stress/strain behavior.
Chaotic Features of Flow in Polymer Processing Equipment-Relevance to Distributive Mixing
Authors: Cheng H. , Manas-Zloczower I.
Published: December 2013

The dominant distributive mixing mechanism in polymer processing is convection. Convection, involving movement of fluid elements from one spatial location in the system to another, results in the creation of interfacial area. Length stretch distributions can be used as a measure of distributive mixing efficiency. We have studied the dynamics of distributive mixing in single and tangential twin screw extruders by means of tracking the evolution of particles originally gathered as clusters. Length stretch distributions and the dynamics of the average length stretch indicate that the tangential twin screw extruder is a better mixing device by comparison with the single screw extruder. The chaotic features of flow in these devices, studied by means of Poincaré sections and Lyapunov exponents, correlate well with the distributive mixing efficiency of the equipment.
Continuous Mixing of Low Viscosity and High Viscosity Polymer Melts in a Modular Co-Rotating Twin Screw Extruder
Authors: Lee S.-H. , White J. L.
Published: December 2013

Modular self-wiping co-rotating twin screw extruders have been widely used in polymer blending and compounding over the past four decades since they were first commercialized by Werner and Pfleiderer [1]. Despite its importance in the polymer processing industry, studies of the initial mixing process in a modular co-rotating twin screw extruder of binary polymer blends have received little attention until the last three years [2 to 9]. Among the various factors controlling the mixing of thermoplastic blends, the viscosity characteristics are a major determinant the degree of deformation of a disperse phase domain depends greatly upon the viscosity ratio. When one component of the mixing system has a very low viscosity, and there is an extremely large viscosity ratio, it is well known to be very difficult to mix [10 to 12].
Flow Field Analysis of Both the Trilobal Element and Mixing Disc Zones within a Closely Intermeshing, Co-Rotating Twin-Screw Extruder
Authors: Bruce D. , Wilson M. , Generalis S.
Published: December 2013

Of the different mixing modules contained within the closely intermeshing, co-rotating twin-screw extruder (CICo-TSE), the trilobal elements and mixing discs are of major importance to the mixing efficiency. These two types of mixing element impose contrasting mixing behaviour on the viscous melt and are thus used selectively to perform differing mixing tasks. Problems encountered when solving the flow problem within these two mixing element zones arise from both the complex 3D geometry and the time dependent flow boundaries as each respective element type rotates about its fixed axes. Following on from the 2D results reported, the computational fluid dynamics package, Polyflow, was employed to investigate the mixing mechanisms exhibited by both a set of three trilobe element pairs and by a pair of staggered mixing discs, as utilised within the Betol BTS40 CICo-TSE. The flow fields were simulated using the ideal rheological properties of polypropylene and characterised in terms of velocity vectors, shear stresses generated and a mixing parameter λ, which quantifies the elongational and rotational flow components. Each flow field exhibited different characteristics for the configurations investigated and it has been found that the average flow field parameter values for the trilobe elements change periodically, whereas minimal changes are observed as the mixing discs rotate.
Temperature Rise in the Extrusion of Highly Viscous Composite Materials
Authors: Sbarski I. , Kosior E. , Bhattacharya S. N.
Published: December 2013

In this paper a model has been developed for the approximate evaluation of the temperature rise in the extrusion of filled plastic materials. The model developed in this paper considers the influence of thermal and rheological properties of extrudate, operating conditions of extrusion and geometry of screw channel on the temperature of extrudate. The optimal parameters of screw channel in terms of productivity and temperature build-up are discussed. The model was tested by experimental studies in which filled plastic material was produced using ground rubber tyre particles dispersed in LDPE. The agreement between the model prediction and the experimental data is discussed.
Simulation of Free Surface Flow in Partially Filled Internal Mixers
Authors: Nassehi V. , Ghoreishy M. H. R.
Published: December 2013

Internal mixers used in rubber processing and other industries are always partially filled. This results in the establishment of multiple random free surfaces in the flow field generated inside these mixers. Therefore successful mathematical modelling of internal mixing process depends on the development of efficient techniques for the reliable simulation of complex free surface flows. Various interface tracking and boundary capturing methods have been used in the past to model this kind of flow regimes. In particular, in recent years the well-known volume of fluid (VOF) method has been frequently used to model a variety of processes involving free surface and moving boundary flows. Both Eulerian and Lagrangian frameworks can be adopted in the VOF scheme to simulate free surface regimes. Under realistic flow conditions, however, the straightforward application of the technique in both frameworks may yield inaccurate results unless elaborate solution strategies are used to avoid errors. In many cases the use of such elaborate schemes requires excessive computational costs and effort or the solution scheme becomes complex and inflexible. In this paper we describe a relatively simple free surface tracking method based on the application of the VOF method in an Eulerian framework. In this scheme the flow field inside a partially filled internal mixer is treated as a two-phase system consisting of incompressible and compressible phases. The sections filled with the fluid which is being mixed are always regarded as an incompressible phase. The parts which are filled with air (or voids in some applications) form the second phase in the present two-phase flow analysis. The latter phase is treated as a compressible or an incompressible fluid (or pseudo fluid in the case of voids) depending on the value of the pressure calculated at each time step for the sections which contain it. We show that free surface flow of highly viscous fluids in partially filled internal mixers can be very successfully simulated by this method.
Injection Moulding of Rubber Compounds1
Authors: Karam S. , Vincent M. , De Zelicourt Y.
Published: December 2013

The aim of this study is to show the relevant physical parameters related to rubber injection moulding, and especially compressibility, vulcanisation and wall slippage. Three materials are studied: an SBR compound, without and with a lubricant, and an EPDM compound. The viscosity is determined by capillary rheometry. The modified SBR exhibits wall slippage. Rheological vulcanisation kinetics are determined with a Moving Die Rheometer. Precise moulding experiments are carried out with an injection moulding machine and a mould equipped with pressure and temperature transducers. At low flow rate, the influence of the curing reaction on the pressure appears clearly especially for the fast curing EPDM. The conditions in which surface scorch defects appear are determined. The SBR with lubricant needs a lower pressure to fill the cavity than without lubircant. A model of mould filling is developed. The material is purely viscous, with a state of cure dependence of the viscosity. A Norton friction law is introduced to take into account a possible slippage at the cavity walls. A compressible calculation in the injection chamber allows a realistic evaluation of the flow rate at the entry of the cavity. The comparison with the experimental data confirms the importance of the compressibility, and the influence of the vulcanisation on the viscosity at low flow rate. In moulding conditions for which vulcanisation is not activated during the filling stage, despite uncertainties on the friction law parameters appropriate to the cavity wall roughness, the agreement with experiments is better when wall slippage is taken into account.
Fluid Mechanics of Intermeshing Counter-Rotating Twin Screw Extruders
Authors: Hong M.-H. , White J. L.
Published: December 2013

A simulation is presented of the flow and pumping behavior of an intermeshing counter-rotating twin screw extruder. The problem of incorporating the positive displacement characteristics of moving machine parts in a cylindrical coordinate Flow Analysis Network (FAN) analysis is presented. Screw pumping characteristic curves were determined for various elements of the Leistritz GG modular counter-rotating twin screw extruder for a Newtonian fluid. We discuss the analysis of composite modular counter-rotating twin screw extruders using these screw pumping characteristics.
Consistency and Generalization Bounds for Maximum Entropy Density Estimation
Authors: Wang Shaojun , Greiner Russell , Wang Shaomin
Published: December 2013

We investigate the statistical properties of maximum entropy density estimation, both for the complete data case and the incomplete data case. We show that under certain assumptions, the generalization error can be bounded in terms of the complexity of the underlying feature functions. This allows us to establish the universal consistency of maximum entropy density estimation.
Structural Patterns in Complex Systems Using Multidendrograms
Authors: Gómez Sergio , Fernández Alberto , Granell Clara , Arenas Alex
Published: December 2013

Complex systems are usually represented as an intricate set of relations between their components forming a complex graph or network. The understanding of their functioning and emergent properties are strongly related to their structural properties. The finding of structural patterns is of utmost importance to reduce the problem of understanding the structure–function relationships. Here we propose the analysis of similarity measures between nodes using hierarchical clustering methods. The discrete nature of the networks usually leads to a small set of different similarity values, making standard hierarchical clustering algorithms ambiguous. We propose the use of multidendrograms, an algorithm that computes agglomerative hierarchical clusterings implementing a variable-group technique that solves the non-uniqueness problem found in the standard pair-group algorithm. This problem arises when there are more than two clusters separated by the same maximum similarity (or minimum distance) during the agglomerative process. Forcing binary trees in this case means breaking ties in some way, thus giving rise to different output clusterings depending on the criterion used. Multidendrograms solves this problem by grouping more than two clusters at the same time when ties occur.
The Evolutionary Puzzle of Suicide
Authors: Aubin Henri-Jean , Berlin Ivan , Kornreich Charles
Published: December 2013

Mechanisms of self-destruction are difficult to reconcile with evolution’s first rule of thumb: survive and reproduce. However, evolutionary success ultimately depends on inclusive fitness. The altruistic suicide hypothesis posits that the presence of low reproductive potential and burdensomeness toward kin can increase the inclusive fitness payoff of self-removal. The bargaining hypothesis assumes that suicide attempts could function as an honest signal of need. The payoff may be positive if the suicidal person has a low reproductive potential. The parasite manipulation hypothesis is founded on the rodent—Toxoplasma gondii host-parasite model, in which the parasite induces a “suicidal” feline attraction that allows the parasite to complete its life cycle. Interestingly, latent infection by T. gondii has been shown to cause behavioral alterations in humans, including increased suicide attempts. Finally, we discuss how suicide risk factors can be understood as nonadaptive byproducts of evolved mechanisms that malfunction. Although most of the mechanisms proposed in this article are largely speculative, the hypotheses that we raise accept self-destructive behavior within the framework of evolutionary theory.
Analysis of the Binding Sites of Porcine Sialoadhesin Receptor with PRRSV
Authors: Jiang Yibo , Khan Faheem , Pandupuspitasari Nuruliarizki , Kadariya Ishwari , Cheng Zhangrui , Ren Yuwei , Chen Xing , Zhou Ao , Yang Liguo , Kong Dexin , Zhang Shujun
Published: December 2013

Porcine reproductive and respiratory syndrome virus (PRRSV) can infect pigs and cause enormous economic losses to the pig industry worldwide. Porcine sialoadhesin (pSN) and CD163 have been identified as key viral receptors on porcine alveolar macrophages (PAM), a main target cell infected by PRRSV. In this study, the protein structures of amino acids 1–119 from the pSN and cSN (cattle sialoadhesin) N-termini (excluding the 19-amino acid signal peptide) were modeled via homology modeling based on mSN (mouse sialoadhesin) template structures using bioinformatics tools. Subsequently, pSN and cSN homology structures were superposed onto the mSN protein structure to predict the binding sites of pSN. As a validation experiment, the SN N-terminus (including the wild-type and site-directed-mutant-types of pSN and cSN) was cloned and expressed as a SN-GFP chimera protein. The binding activity between SN and PRRSV was confirmed by WB (Western blotting), FAR-WB (far Western blotting), ELISA (enzyme-linked immunosorbent assay) and immunofluorescence assay. We found that the S107 amino acid residue in the pSN N-terminal played a crucial role in forming a special cavity, as well as a hydrogen bond for enhancing PRRSV binding during PRRSV infection. S107 may be glycosylated during PRRSV infection and may also be involved in forming the cavity for binding PRRSV along with other sites, including W2, Y44, S45, R97, R105, W106 and V109. Additionally, S107 might also be important for pSN binding with PRRSV. However, the function of these binding sites must be confirmed by further studies.
N-Terminal Protease Gene Phylogeny Reveals the Potential for Novel Cyanobactin Diversity in Cyanobacteria
Authors: Martins Joana , Leão Pedro , Ramos Vitor , Vasconcelos Vitor
Published: December 2013

Cyanobactins are a recently recognized group of ribosomal cyclic peptides produced by cyanobacteria, which have been studied because of their interesting biological activities. Here, we have used a PCR-based approach to detect the N-terminal protease (A) gene from cyanobactin synthetase gene clusters, in a set of diverse cyanobacteria from our culture collection (Laboratory of Ecotoxicology, Genomics and Evolution (LEGE) CC). Homologues of this gene were found in Microcystis and Rivularia strains, and for the first time in Cuspidothrix, Phormidium and Sphaerospermopsis strains. Phylogenetic relationships inferred from available A-gene sequences, including those obtained in this work, revealed two new groups of phylotypes, harboring Phormidium, Sphaerospermopsis and Rivularia LEGE isolates. Thus, this study shows that, using underexplored cyanobacterial strains, it is still possible to expand the known genetic diversity of genes involved in cyanobactin biosynthesis.
The Pattern and Process of Adoption and Scaling up: Variation in Project Outcome Reveals the Importance of Multilevel Collaboration in Agroforestry Development
Authors: Johansson Karl-Erik , Axelsson Robert , Kimanzu Ngolia , Sassi Samuel , Bwana Eliza , Otsyina Robert
Published: December 2013

Agroforestry is considered a subsistence system that balances the urgent need for food and income of small scale farmers with restoration and conservation of ecosystem services, and climate change adaptation and mitigation. The Vi Agroforestry Program aims to implement agroforestry as a means to alleviate poverty and increase resilience among the poorest smallholders. After seven years, the Vi Agroforestry Project in the Mara Region of Tanzania had an inter-village variation in the proportion of households with tangible surviving agroforestry trees ranging from 10%–90%. Using a multiple methods approach, this variation was analysed in relation to changes and differences among administrative districts and project zones regarding perceived barriers to agroforestry adoption, project interventions, governance and the chronology of the process. In districts and zones where collaboration among the project staff, government counterparts and other stakeholders had been established at multiple levels, more agroforestry trees survived and a larger proportion of households practiced agroforestry. The established collaboration made it possible to discover and consider opportunities and barriers to agroforestry development such as diverse stakeholder interests and perceptions. As a result, potential conflicts could be avoided and socially robust solutions developed, adapted and integrated into the local subsistence systems.
Effect of Symmetry Breaking on Electronic Band Structure: Gap Opening at the High Symmetry Points
Authors: Vasseur Guillaume , Fagot-Revurat Yannick , Kierren Bertrand , Sicot Muriel , Malterre Daniel
Published: December 2013

Some characteristic features of band structures, like the band degeneracy at high symmetry points or the existence of energy gaps, usually reflect the symmetry of the crystal or, more precisely, the symmetry of the wave vector group at the relevant points of the Brillouin zone. In this paper, we will illustrate this property by considering two-dimensional (2D)-hexagonal lattices characterized by a possible two-fold degenerate band at the K points with a linear dispersion (Dirac points). By combining scanning tunneling spectroscopy and angle-resolved photoemission, we study the electronic properties of a similar system: the Ag/Cu(111) interface reconstruction characterized by a hexagonal superlattice, and we show that the gap opening at the K points of the Brillouin zone of the reconstructed cell is due to the symmetry breaking of the wave vector group.
Preclinical and Clinical Development of a YFV 17 D-Based Chimeric Vaccine against West Nile Virus
Authors: Dayan Gustavo , Pugachev Konstantin , Bevilacqua Joan , Lang Jean , Monath Thomas
Published: December 2013

Substantial success has been achieved in the development and implementation of West Nile (WN) vaccines for horses; however, no human WN vaccines are approved. This review focuses on the construction, pre-clinical and clinical characterization of ChimeriVax-WN02 for humans, a live chimeric vaccine composed of a yellow fever (YF) 17D virus in which the prM-E envelope protein genes are replaced with the corresponding genes of the WN NY99 virus. Pre-clinical studies demonstrated that ChimeriVax-WN02 was significantly less neurovirulent than YF 17D in mice and rhesus and cynomolgus monkeys. The vaccine elicited neutralizing antibody titers after inoculation in hamsters and monkeys and protected immunized animals from lethal challenge including intracerebral inoculation of high dose of WN NY99 virus. Safety, viremia and immunogenicity of ChimeriVax-WN02 were assessed in one phase I study and in two phase II clinical trials. No safety signals were detected in the three clinical trials with no remarkable differences in incidence of adverse events (AEs) between vaccine and placebo recipients. Viremia was transient and the mean viremia levels were low. The vaccine elicited strong and durable neutralizing antibody and cytotoxic T cell responses. WN epidemiology impedes a classical licensure pathway; therefore, innovative licensure strategies should be explored.
Lateral and medial tibial plateau angles in normal dogs
Authors: Ocal M. K. , Sabanci S. S.
Published: December 2013

To measure lateral and medial tibial plateau angle values in isolated canine tibiae and to compare lateral and medial tibial plateau angle values between dogs based on sex and breed.

Tibiae of 90 dogs from 24 different breeds were used. Photographs were taken of the medial and lateral aspects of the tibiae for measurement of the medial and lateral tibial plateau angles. Additionally, the medial tibial plateau angle was measured from radiographs of the tibiae. Two-way analysis of variance was used to test the effects of side, sex and breed on the medial and lateral tibial plateau angles as measured from photographs as well as the medial tibial plateal angles as measured from radiographs. The photographic and radiographic medial tibial plateau angles were compared by paired t-test, whereas the medial and lateral photographic tibial plateau angles were compared by t-test.

When all dogs were included in the analysis, the difference between the mean medial tibial plateau angle (24.0 ± 3.19°) and the mean lateral tibial plateau angle (25.5 ± 3.84°) as measured from photographs was significant (p <0.05). The difference in the photographic medial tibial plateau angle between male and female dogs was significant (p <0.05), whereas the difference in the photographic lateral tibial plateau angle between sexes was not significant. There was a significant difference between the medial and lateral tibial plateau angles as measured from photographs in male dogs (p <0.05) but not in female dogs. Breed comparisons also showed significant differences for the photographic lateral tibial plateau angle (p <0.05).

The axial rotation of the femoral condyles on the tibial plateau is probably affected by the discrepancy between the medial and lateral tibial plateau angles, and this difference in certain breeds might influence the prevalence of cranial cruciate ligament disease.
Rapid prototyping to design a customized locking plate for pancarpal arthrodesis in a giant breed dog
Authors: Nicetto T. , Petazzoni M.
Published: December 2013

This report describes the treatment of traumatic carpal hyperextension in a giant breed dog by pancarpal arthrodesis using a custom- made Fixin locking plate, created with the aid of a three-dimensional plastic model of the bones of the antebrachium produced by rapid prototyping technology.

A three-year-old 104 kg male Mastiff dog was admitted for treatment of carpal hyperextension injury. After diagnosis of carpal instability, surgery was recommended. Computed tomography images were used to create a life-size three-dimensional plastic model of the forelimb. The model was used as the basis for constructing a customized 12-hole Fixin locking plate. The plate was used to attain successful pancarpal arthrodesis in the animal.

Radiographic examination after 74 and 140 days revealed signs of osseous union of the arthrodesis. Further clinical and radiographic follow-up examination three years later did not reveal any changes in implant position or complications.
N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation
Authors: Fischer Julian , Millan Simon , Ritter Helmut
Published: December 2013

N-alkylation of N,N'-(hexane-1,6-diyl)bis(4-methylbenzenesulfonamide) with allyl bromide and subsequent Prilezhaev reaction with m-chloroperbenzoic acid to give N,N'-(hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide) is described. This twofold alkylation was performed in aqueous solution, whereby α-, and randomly methylated β-cyclodextrin were used as adequate phase transfer catalysts and the cyclodextrin–guest complexes were characterized by 1H NMR and 2D NMR ROESY spectroscopy. Finally, the curing properties of the diepoxide with lysine-based α-amino-ε-caprolactam were analyzed by rheological measurements.
The Gentlemen’s Club: An innovation to improve HIV counselling and testing uptake at a South African university campus
Authors: Matlala Sogo F. , Mokono Selokela J. , Tsotetsi Pontsho
Published: December 2013

Background: Many university students were found to be engaging in high HIV risk practiceson campuses which then necessitated discovering their HIV status by participating in HIVcounselling and testing (HCT) campaigns. HCT is an entry point into a comprehensivecontinuum of prevention, treatment, care and support services for HIV infection and AIDS.However, it was also found that many students, mostly males, did not take regular HIV teststo discover their HIV status and receive the necessary counselling and support.Objectives: The innovative Gentlemen’s Club was therefore implemented at a universitycampus to increase HCT uptake.The club was formed to motivate male students on behaviourand lifestyle changes so that they could become responsible men.Method: To join the club, a student was required to take a confidential HIV test and as amember he was expected to follow rules of good and responsible behaviour as prescribed bythe club.Results: Club membership and attendance for meetings showed an increase after the launchof the club in 2010 because of its appeal, and there was also a notable increase in the numberof male students attending HCT campaigns. Women have formed a similar club to motivateother women to take regular HIV tests as well.Conclusion: The Gentlemen’s Club was an innovative idea that increased HCT uptake by malestudents and served as vehicle to address health and social issues facing university students.
A new vehicle emission inventory for China with high spatial and temporal resolution
Authors: Zheng B. , Huo H. , Zhang Q. , Yao Z. L. , Wang X. T. , Yang X. F. , Liu H. , He K. B.
Published: December 2013

Abstract. This study is the first in a series of papers that aim to develop high-resolution emission databases for different anthropogenic sources in China. Here we focus on on-road transportation. Because of the increasing impact of on-road transportation on regional air quality, developing an accurate and high-resolution vehicle emission inventory is important for both the research community and air quality management. This work proposes a new inventory methodology to improve the spatial and temporal accuracy and resolution of vehicle emissions in China. We calculate, for the first time, the monthly vehicle emissions (CO, NMHC, NOx, and PM2.5) for 2008 in 2364 counties (an administrative unit one level lower than city) by developing a set of approaches to estimate vehicle stock and monthly emission factors at county-level, and technology distribution at provincial level. We then introduce allocation weights for the vehicle kilometers traveled to assign the county-level emissions onto 0.05° × 0.05° grids based on the China Digital Road-network Map (CDRM). The new methodology overcomes the common shortcomings of previous inventory methods, including neglecting the geographical differences between key parameters and using surrogates that are weakly related to vehicle activities to allocate vehicle emissions. The new method has great advantages over previous methods in depicting the spatial distribution characteristics of vehicle activities and emissions. This work provides a better understanding of the spatial representation of vehicle emissions in China and can benefit both air quality modeling and management with improved spatial accuracy.
Modelling complex geological angular data with the Projected Normal distribution and mixtures of von Mises distributions
Authors: Lark R. M. , Clifford D. , Waters C. N.
Published: December 2013

Abstract. Angular data are commonly encountered in the earth sciences and statistical descriptions and inferences about such data are necessary in structural geology. In this paper we compare two statistical distributions appropriate for complex angular data sets: the mixture of von Mises and the projected normal distribution. We show how the number of components in a mixture of von Mises distribution may be chosen, and how one may chose between the projected normal distribution and mixture of von Mises for a particular data set. We illustrate these methods with some structural geological data, showing how the fitted models can complement geological interpretation and permit statistical inference. One of our data sets suggests a special case of the projected normal distribution which we discuss briefly.
Importance of basal processes in simulations of a surging Svalbard outlet glacier
Authors: Gladstone R. , Schäfer M. , Zwinger T. , Gong Y. , Strozzi T. , Moore J. , Mottram R. , Boberg F.
Published: December 2013

Abstract. The outlet glacier of Basin 3 (B3) of Austfonna icecap, Svalbard, is one of the fastest outlet glaciers in Svalbard, and shows dramatic changes since 1995. In addition to previously observed seasonal summer speed up associated with the melt season, the winter speed of B3 has accelerated approximately five fold since 1995. We use the Elmer/Ice full Stokes model for ice dynamics to infer spatial distributions of basal drag for the winter seasons of 1995, 2008 and 2011. This "inverse" method is based on minimising discrepancy between modelled and observed surface velocities, using satellite remotely sensed velocity fields. We generate steady state temperature distributions for the three time periods. Frictional heating caused by basal sliding contributes significantly to basal temperatures of the B3 outlet glacier, which exhibits a uniform steady state basal temperature at pressure melting point in all three cases. We present a sensitivity experiment consisting of transient simulations under present day forcing to demonstrate that using a temporally fixed basal drag field obtained through inversion can lead to thickness change errors of the order of 2 m per year. Hence it is essential to incorporate the evolution of basal processes in future projections of the basin. Informed by a combination of our inverse method results and previous studies, we hypothesize a system of processes and feedbacks involving till deformation and basal hydrology to explain both the seasonal accelerations and the ongoing inter-annual speed up, and speculate on the wider relevance of deformable till mechanics to non-surging glaciers.
Considerações sobre alguns aspectos hidrogeológicos da Formação Bauru
Authors: Carvalho Moacyr de
Published: December 2013

A finalidade deste trabalho é tecer algumas considerações sobre. alguns aspectos hidrogeológicos da "Formação Bauru" e a possibilidade da existência de uma rede de comunicações hidráulicas entre as Formações "Bauru" e "Botucatu", através da barreira de derrames basálticos que as separa. Esta barreira é conhecida como "Formação Serra Geral". Os poços tubulares perfurados pelo Instituto Geológico têm freqüentemente atingido e mesmo penetrado o piso basáltico sobre o qual repousa a "Formação Bauru". Este fato tem influenciado o comportamento hidráulico desses poços, comportamento este que pode ser sentido na análise do conjunto de 91 poços considerados neste trabalho. A hipótese de recarga inferior da "Formação Bauru" através da "Formação Botucatu" se baseia em alguns fatos ligados a aspectos geológicos e hidrogeológicos conhecidos. Acredita-se que, do ponto de vista hidrogeológico, ambas as Formações deveriam ser estudadas em conjunto, devido a possível existência de uma dinâmica de águas subterrâneas abrangendo ambas as Formações
Um método para avaliação aproximada de coeficientes de permeabilidade em aquíferos
Authors: Carvalho Moacyr de
Published: December 2013

o presente trabalho é uma tentativa para a obtenção de valores aproximados de coeficiente de permeabilidade de aqüíferos em cuja estrutura' ocorrem camadas .ou estratos diversos de sedimentos. O método consiste na essência, partindo de certas condições restritivas, no estabelecimento de um sistema de equações lineares utilizando-se de dados conhecidos de poços tubulares numa área limitada, sob a hipótese de que cada estrato doaqüífero se· comporte como um aqüífero individual de lençol livre. Um exemplo de aplicação é apresentado com dados retirados de 3 poços tubulares da cidade de Catanduva, porém com estratificações sedimentares imaginárias devido a inexistência de uma descrição adequada dos perfís geológicos. Observamos também que tais poços não obedecem as condições restritivas impostas no método, por receberem contribuições de rochas fraturadas subjacentes, provavelmente de água proveniente da Formação Botucatu.
Interpretação geocronológica preliminar da Bacia do Paraná
Authors: Vieira Percy Corrêa
Published: December 2013

Os dados geocronológicos obtidos para as Formações, Ponta Grossa, Rio Bonito, Irati, Estrada Nova, Rio do Rasto e Pirambóia, contidos no método proposto no boletim da American Association of Petroleum Geologists (AAPG), bem como o modelo de evolução tectônica do sudeste e sul do Brasil proposto na Série Projeto Remac, mostram que no Permo-Triássico (talvez antes) teve origem longo estágio de arqueamento gonduânico com soerguimento crustal, o qual provocou o surgimento de área dômica no sudeste do Brasil, cujo auge deu-se no Triássico-Jurássico (há cerca de cento e oitenta milhões de anos). Esse evento provocou rehomogeneização isotópica do estrôncio nas Formações, Ponta Grossa, Irati, Estrada Nova e talvez Rio do Rasto, do centro norte do Estado de Santa Catarina ao centro oeste do Estado de São Paulo. Por essa época a Formação Pirambóia encontrava-se recém-sedimentada ou em sedimentação, ou ainda a sedimentar-se e assim só veio a sentir os efeitos rehomogeneizantes provocados pelo derramamento basáltico juro-cretáceo de cerca de cento e trinta milhões de anos atrás, fruto de manifestação téctono-magmática
Subprovíncias hidrogeológicas do Grupo Bauru na região norte-ocidental do estado de São Paulo
Authors: Barcha Samir Felício , Arid Fahad Moysés , Mezzalira Sérgio
Published: December 2013

Face à crescente demanda de água para fins industrial, agrícola e urbano, estão sendo construídos numerosos poços profundos na região norte-ocidental do Estado de São Paulo, visando a captação de água subterrânea contida nos aquíferos dos sedimentos do Grupo Bauru. Estes poços têm revelado substanciais diferenças em suas vazões, consequência não apenas de suas características técnicas de construção, mas especialmente devidas a fatores geológicos. Os dados obtidos permitiram estabelecer, como causas fundamentais desta variação, a porosidade e a permeabilidade, as quais variam em função da textura, do teor e do comportamento do cimento carbonático. Verificou-se também que a variação na produtividade tem significação regional, isto é, apresenta valores diversos em diferentes áreas. Baseados neste fato, os autores puderam estabelecer a existência de, pelo menos, três subprovíncias hidrogeológicas na região estudada, delimitando, ainda que de forma preliminar, áreas mais e menos promissoras para a exploração de água subterrânea.
Geologia do município de Santa Rita do Passa Quatro, SP
Authors: Massoli Marcos
Published: December 2013

Este trabalho teve por finalidade a obtenção do mapa geológico do Município de Santa Rita do Passa Quatro, Estado de São Paulo, até então não existente na literatura geológica. Foram mapeadas as formações: Corumbataí, Pirambóia, Botucatu, Serra Geral e Santa Rita do Passa Quatro, além dos depósitos quaternários.
The difficult, the dangerous, and the catastrophic: Managing the spectrum of climate risks
Authors: Luers Amy L. , Sklar Leonard S.
Published: December 2013

The notion of a threshold of dangerous climate change has been central to national and international efforts to address climate risks. However, the focus on a single target has now become an obstacle because it reinforces three key problems: it frames climate change as a distant abstract threat, it impedes integration of mitigation and adaptation, and it fails to recognize the diversity of values and risk perceptions of people around the globe. We present an alternative framework that considers both biophysical science and social values in characterizing the broad spectrum of climate risks. The framework also presents the options for managing these risks within four quadrants defined by the inherent limits to mitigation and adaptation. This quadrant‐based approach to managing the spectrum of climate risks restructures the climate change problem from avoiding a distant catastrophe to minimizing collective suffering.
Herpes simplex virus encephalitis is a trigger of brain autoimmunity
Authors: Armangue Thaís , Leypoldt Frank , Málaga Ignacio , Raspall‐Chaure Miquel , Marti Itxaso , Nichter Charles , Pugh John , Vicente‐Rasoamalala Monica , Lafuente‐Hidalgo Miguel , Macaya Alfons , Ke Michael , Titulaer Maarten J. , Höftberger Romana , Sheriff Heather , Glaser Carol , Dalmau Josep
Published: December 2013

In 5 prospectively diagnosed patients with relapsing post–herpes simplex encephalitis (HSE), N‐methyl‐D‐aspartate receptor (NMDAR) antibodies were identified. Antibody synthesis started 1 to 4 weeks after HSE, preceding the neurological relapse. Three of 5 patients improved postimmunotherapy, 1 spontaneously, and 1 has started to improve. Two additional patients with NMDAR antibodies, 9 with unknown neuronal surface antibodies, and 1 with NMDAR and unknown antibodies, were identified during retrospective assessment of 34 HSE patients; the frequency of autoantibodies increased over time (serum, p = 0.004; cerebrospinal fluid, p = 0.04). The 3 retrospectively identified NMDAR antibody–positive patients also had evidence of relapsing post‐HSE. Overall, these findings indicate that HSE triggers NMDAR antibodies and potentially other brain autoimmunity. Ann Neurol 2014;75:317–323
The Witkop Cyclization: A Photoinduced CH Activation of the Indole System
Authors: Gritsch Philipp J. , Leitner Christian , Pfaffenbach Magnus , Gaich Tanja
Published: December 2013

Investigations of excited‐state redox processes have an exceptional impact on the field of organic photochemistry and its application to the synthesis of complex target molecules. In such a photochemical process a single‐electron transfer takes place to produce ion‐radical intermediates, if the reduction and oxidation potentials, as well as excited‐state energies of electron donors and acceptors are chosen appropriately. The Witkop cyclization constitutes an intramolecular variant of such a process, typically with an indole heterocycle as an electron donor. The specific synthetic value of this reaction lies in a CC bond formation without requiring any prefunctionalization of the indole system. Although this photoreaction has been applied to the total synthesis of natural products, it has still not been used to its full capacity. The following review details synthetic efforts using the Witkop cyclization, and aims to incite further applications of reaction in the synthesis of complex molecular architectures.
Fabrication and processing of polypropylene ‐ paraffin compounds with enhanced thermal and processing properties: Impact penetration and thermal characterization
Authors: Saleem Anjum , Frormann Lars , Koltermann Jan , Reichelt Claudia
Published: December 2013

The compounds of polypropylene (PP) with paraffin wax (PR) as phase change material were fabricated by extrusion melt compounding. The compounds of PR and PP were brittle and showed PR leakage within its melting point range. The maximum 60 weight percent content of the PR was compounded with the polymer. The high amount of paraffin in the polymer plasticized and significantly decreased the melting point of the polymer. The addition of a linear triblock copolymer based on styrene and ethylene/butylene noticeably ameliorated the workability, impact penetration and paraffin retention properties of the compounds. The compounds were further reinforced by carbon fibers and carbon nanotubes that led to an enhancement of their thermal conductivity and heat transfer efficiency. The material structure and thermophysical properties were studied by microscopy and various characterization techniques. The compounds of polymer with PR show phase change effect due to the solid–liquid phase transition of PR within its melting point range. The experimental time vs. temperature curves of the compounds were recorded within the melting range of PR. The experimental curves were compared with the theoretical calculated results. The results were in agreement except small difference that can be attributed to the experimental errors and the assumptions made during theoretical calculations. The manuscript describes the fabrication of shape enduring compounds, with improved thermal, physical, and mechanical properties and their processing by standard techniques, such as extrusion and blow molding. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40164.